WorldWideScience

Sample records for atmospheric precipitations

  1. Parameterization of ionization induced in the atmosphere by precipitating particles

    Science.gov (United States)

    Artamonov, Anton; Usoskin, Ilya; Kovaltsov, Gennady

    We present a physical model to calculate ionization induced in the atmosphere by precipitating particles. This model is based on the Bethe-Bloch equation applied for precipitating particles such as: electrons, alpha-particles and protons. The energy range of precipitating particles is up to 5MeV and 80MeV/nuc respectively. This model provides an easy implementation with a robust realization of model calculations for a wide range of incident energies of precipitating particles. This method is limited to the upper-middle atmosphere. An ionization yield function [see, Usoskin and Kovaltsov, 2006; Usoskin, Kovaltsov, Mironova, 2010] can be also used in this model, making it possible to calculate the atmospheric ionization effect of precipitating particles for the entire atmosphere, dawn to the ground.

  2. Sampling of Atmospheric Precipitation and Deposits for Analysis of Atmospheric Pollution

    OpenAIRE

    J. Namieśnik; K. Skarżyńska; Ż Polkowska

    2006-01-01

    This paper reviews techniques and equipment for collecting precipitation samples from the atmosphere (fog and cloud water) and from atmospheric deposits (dew, hoarfrost, and rime) that are suitable for the evaluation of atmospheric pollution. It discusses the storage and preparation of samples for analysis and also presents bibliographic information on the concentration ranges of inorganic and organic compounds in the precipitation and atmospheric deposit samples.

  3. Satellite Estimates of Precipitation-Induced Dissipation in the Atmosphere

    Science.gov (United States)

    Pauluis, Olivier; Dias, Juliana

    2012-02-01

    A substantial amount of frictional dissipation in the atmosphere occurs in the microphysical shear zones surrounding falling precipitation. The dissipation rate is computed here from recently available satellite retrieval from the Tropical Rainfall Measurement Missions and is found to average 1.8 watts per square meter between 30°S and 30°N. The geographical distribution of the precipitation-induced dissipation is closely tied to that of precipitation but also reveals a stronger dissipation rate for continental convection than for maritime convection. Because the precipitation-induced dissipation is of the same magnitude as the turbulent dissipation of the kinetic energy in the atmosphere, changes in the hydrological cycle could potentially have a direct impact on the amount of kinetic energy generated and dissipated by the atmospheric circulation.

  4. Isotopic composition of precipitation during different atmospheric circulation patterns

    Science.gov (United States)

    Brenčič, Mihael; Kononova, Nina; Vreča, Polona

    2016-04-01

    Precipitation generating processes depend on atmospheric circulation patterns and consequently it is expected that its water stable isotopic composition of hydrogen and oxygen is related to them. Precipitation generated at similar atmospheric circulation patterns should have similar empirical distribution of δ2H and δ18O values. There are several approaches in which atmospheric circulation patterns are classified as elementary air circulation mechanisms - ECM; in our approach we have applied Dzerdzeevskii classification. Two types of models of relation between ECM and isotopic composition of precipitation are proposed; first is based on the linear combination of δ2H and δ18O values with precipitation amount weighted average (Brenčič et al., 2015) and the second new one is based on the multiple regression approach. Both approaches make possible also to estimate empirical distributions' dispersion parameters. Application of the models is illustrated on the precipitation records from Ljubljana and Portorož GNIP stations, Slovenia. Estimated values of the parameters for empirical distributions of δ2H and δ18O of each ECM subtype have shown that calculated estimates are reasonable. Brenčič, M., Kononova, N.K., Vreča, P., 2015: Relation between isotopic composition of precipitation and atmospheric circulation patterns. Journal of Hydrology 529, 1422-1432: doi: 10.1016/j.jhydrol.2015.08.040

  5. Relation between isotopic composition of precipitation and atmospheric circulation patterns

    Science.gov (United States)

    Brenčič, Mihael; Kononova, Nina K.; Vreča, Polona

    2015-10-01

    Precipitation generating processes depend on atmospheric circulation patterns and consequently it is expected that its water stable isotopic composition of hydrogen and oxygen is related to them. Precipitation generated at similar atmospheric circulation patterns should have similar empirical distribution of δ2H and δ18O values. Mathematical model based on the linear combination of δ2H and δ18O values and on precipitation amount weighted average related to elementary air circulation mechanisms - ECM is proposed. The model enables estimation of average δ2H and δ18O values and their standard deviation for the precipitation generated at distinctive atmospheric circulation patterns. Approach in which atmospheric circulation patterns were classified as ECM based on the Dzerdzeevskii classification was applied. Application of the model is illustrated on the long term precipitation record from Ljubljana GNIP station Slovenia. Estimated values of the parameters for empirical distributions of δ2H and δ18O of each ECM subtype have shown that calculated estimates are reasonable. Further applications of the proposed model enable new insight into the understanding of isotopes spatial and temporal distribution in precipitation important also for better understanding of climate proxies.

  6. Precipitating Condensation Clouds in Substellar Atmospheres

    CERN Document Server

    Ackerman, A S; Ackerman, Andrew S; Marley, Mark S.

    2001-01-01

    We present a method to calculate vertical profiles of particle size distributions in condensation clouds of giant planets and brown dwarfs. The method assumes a balance between turbulent diffusion and sedimentation in horizontally uniform cloud decks. Calculations for the Jovian ammonia cloud are compared with results from previous methods. An adjustable parameter describing the efficiency of sedimentation allows the new model to span the range of predictions made by previous models. Calculations for the Jovian ammonia cloud are consistent with observations. Example calculations are provided for water, silicate, and iron clouds on brown dwarfs and on a cool extrasolar giant planet. We find that precipitating cloud decks naturally account for the characteristic trends seen in the spectra and colors of L- and T-type ultracool dwarfs.

  7. Scavenging of radon daughters by precipitation from the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Fujinami, Naoto [Kyoto Prefectural Inst. of Hygienic and Environmental Sciences (Japan)

    1997-02-01

    By the continuous measurement of the radon daughters concentration in the rain and snow water and atmosphere and the data analysis, the following results were obtained. The radon daughters concentration was almost constant in the rain and snow water in spite of the length during weather without precipitation. It has not tendency to show the high concentration of radon daughters in precipitation and snow during beginning of them. When the precipitation intensity is constant, it`s concentration does not change during precipitation and snowfall. The concentration does not depend on the amount of precipitation, but on the precipitation intensity. We did not observe a correlation between the radon daughters concentration in the rain and snow water and that in the surface air. The atmospheric concentration was decreased by precipitation and snowfall, but that of rain and snow water did not decrease. The above results seems to show that the contribution of washout under the cloud to radon daughters in rain and snow water is small and that of rainout in the cloud is large. This result is agreement with the Jacob`s experimental results. (S.Y.)

  8. Martian Atmospheric Dust Mitigation for ISRU Intakes via Electrostatic Precipitation

    Science.gov (United States)

    Phillips, James R., III; Pollard, Jacob R. S.; Johansen, Michael R.; Mackey, Paul J.; Clements, Sid; Calle, Carlos I.

    2016-01-01

    This document is the presentation to be given at the 2016 American Society of Civil Engineers Earth and Space Conference to examine the concept of using electrostatic precipitation for Martian atmospheric dust mitigation of the intakes of in-situ resource utilization reactors.

  9. Characterization of extreme precipitation within atmospheric river events over California

    Science.gov (United States)

    Jeon, S.; Prabhat; Byna, S.; Gu, J.; Collins, W. D.; Wehner, M. F.

    2015-11-01

    Atmospheric rivers (ARs) are large, spatially coherent weather systems with high concentrations of elevated water vapor. These systems often cause severe downpours and flooding over the western coastal United States - and with the availability of more atmospheric moisture in the future under global warming we expect ARs to play an important role as potential causes of extreme precipitation changes. Therefore, we aim to investigate changes in extreme precipitation properties correlated with AR events in a warmer climate, which are large-scale meteorological patterns affecting the weather and climate of California. We have recently developed the TECA (Toolkit for Extreme Climate Analysis) software for automatically identifying and tracking features in climate data sets. Specifically, we can now identify ARs that make landfall on the western coast of North America. Based on this detection procedure, we can investigate the impact of ARs by exploring the spatial extent of AR precipitation using climate model (CMIP5) simulations and characterize spatial patterns of dependence for future projections between AR precipitation extremes under climate change within the statistical framework. Our results show that AR events in the future RCP (Representative Concentration Pathway)8.5 scenario (2076-2100) tend to produce heavier rainfall with higher frequency and longer days than events from the historical run (1981-2005). We also find that the dependence between extreme precipitation events has a shorter spatial range, within localized areas in California, under the high future emissions scenario than under the historical run.

  10. Lead in atmospheric precipitation: Analysis of atmospheric precipitation pollution monitoring data for location “Kamenički vis”, Serbia

    Directory of Open Access Journals (Sweden)

    Ćosović Aleksandar R.

    2013-01-01

    Full Text Available In this paper an overview of data collected during monitoring of lead content in atmospheric precipitation on GAW/EMEP (Global Atmosphere Watch/European Monitoring and Evaluation Programme station “Kamenicki Vis”, Serbia from 2000 to 2010 is given. Annual arithmetic mean concentrations, weighted arithmetic mean concentrations, and median of week samples are presented. Obtained data was compared with results of analysis of atmospheric precipitation collected on experimental EMEP station “Zeleno brdo“, Serbia and discussed in scope of European average levels of lead content in precipitation and air. Significant increase of average annual lead content in precipitation was observed in 2003 and 2007. Observed peaks can not be seen on average European trends thus lead to conclusion that recorded increases are characteristic for local region. In order to further discuss nature and direction of possible sources of detected lead pollution short analysis of lead emission data was performed. An effort was made to gather data from the counties that lay in directions from which dominant winds blow as well as for Serbia. For this purpose total national emissions from LRTAP (Long-range transboudary air pollution Convention emission inventory report and EMEP emission inventory were used as well as data published by relevant national authorities. According to these emission levels, majority of surrounding countries couldn’t have contributed much to the recorded increases of lead content in precipitation. However, several possible sources were revealed. In all studied countries emission levels steadily dropped during the analyzed period, whereas only for Serbia different trend was observed. Presented data leads to conclusion that recorded increase of lead content in precipitation in 2003 probably originates from trans-boundary contributions, while increases in 2007 and onwards may come from Serbia’s own emissions. [Projekat Ministarstva nauke

  11. Martian Atmospheric Dust Mitigation for ISRU Intakes via Electrostatic Precipitation

    Science.gov (United States)

    Phillips, James R., III; Pollard, Jacob R. S.; Johansen, Michael R.; Mackey, Paul J.; Clements, J. Sid; Calle, Carlos I.

    2016-01-01

    The Mars 2020 and Mars Sample Return missions expected to fly to Mars within the next ten years will each include an In Situ Resource Utilization (ISRU) system. They convert carbon dioxide in the Martian atmosphere into consumable oxygen at 1% and 20% of the rate required by a full scale human exploration Mars mission, respectively. The ISRU systems will need to draw in the surrounding atmosphere at a rate of 110L/min and 550L/min, respectively, in order to meet their oxygen production goals. Over the duration of each respective mission, a total atmospheric dust mass of 4.86g and 243g will be drawn into each system, respectively. Ingestion of large quantities of dust may interfere with ISRU operations, so a dust mitigation device will be required. The atmospheric volume and dust mass flow rates above will be utilized to simulate Martian environmental conditions in a laboratory electrostatic precipitator being developed to provide active dust mitigation support for atmospheric ISRU systems such as these.

  12. Tritium in atmospheric precipitations and water systems of Belarus

    International Nuclear Information System (INIS)

    Experimental and literature data concerning analysis of tritium in atmospheric precipitation and natural waters of Belarus including the lakes near the Ignalina NPP are compared and analyzed. It is concluded that the maximum of the curve 'amount of the samples - their activity' is shifted to the higher activity in the period 1994-2000 in comparison with 1980-1989. This increasing of the concentration of tritium in water can not be explained definitely by the Chernobyl accident. Consumption of drinking water with maximum registered tritium concentration in natural waters (10 Bq/l) will produce accumulation of dose equal 1,3·10-3 of public permissible dose limit (authors)

  13. Wet precipitation scavenging of soluble atmospheric trace gases due to chemical absorption in inhomogeneous atmosphere

    Science.gov (United States)

    Elperin, Tov; Fominykh, Andrew; Krasovitov, Boris

    2016-04-01

    We analyze the effects of irreversible chemical reactions of the first and higher orders and aqueous-phase dissociation reactions on the rate of trace gas scavenging by rain in the atmosphere with non-uniform concentration and temperature. We employ an one-dimensional model of precipitation scavenging of chemically active soluble gaseous pollutants that is valid for small gradients of temperature and concentration in the atmosphere. It is demonstrated that transient altitudinal distribution of concentration under the influence of rain is determined by the partial hyperbolic differential equation of the first order. Scavenging coefficients are calculated for wet removal of chlorine, nitrogen dioxide and sulfur dioxide for the exponential and linear initial altitudinal distributions of trace gases concentration in the atmosphere and linear and uniform altitudinal temperature distributions. Theoretical predictions of the dependence of the magnitude of the scavenging coefficient on rain intensity for sulfur dioxide are in a good agreement with the available atmospheric measurements.

  14. Hydrochemical and isotopic investigation of atmospheric precipitation in Beijing, China

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Yuanzheng, E-mail: diszyz@163.com [College of Water Sciences, Beijing Normal University, Beijing 100875 (China); Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education of China, Beijing 100875 (China); Wang, Jinsheng, E-mail: wangjs@bnu.edu.cn [College of Water Sciences, Beijing Normal University, Beijing 100875 (China); Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education of China, Beijing 100875 (China); Zhang, Yang [College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049 (China); Teng, Yanguo; Zuo, Rui; Huan, Huan [College of Water Sciences, Beijing Normal University, Beijing 100875 (China); Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education of China, Beijing 100875 (China)

    2013-07-01

    vapor and the physical and chemical processes occurred along the migration paths of water vapor from sources to the aimed precipitation area. Temporal change of {sup 3}H was only influenced by the nuclear testing in the early 1960s worldwide and the natural yield of {sup 3}H in the upper atmosphere intrinsically. {sup 3}H had nearly approached to the natural levels, which would bring difficulty if not invalidation to groundwater dating using {sup 3}H technique. - Highlights: • Precipitation in Beijing was analyzed for hydrochemical and isotopic composition. • The changes of hydrochemical and isotopic composition from 1979 to 2009 were analyzed. • The origins of major ions of precipitation were identified. • The LMWL was obtained based on the data of 1979, 1980, 2007, 2008, and 2009. • Temporal change of {sup 3}H in precipitation and its influencing factors were revealed.

  15. Evaluation of OTT PLUVIO Precipitation Gage versus Belfort Universal Precipitation Gage 5-780 for the National Atmospheric Deposition Program

    Science.gov (United States)

    Tumbusch, Mary L.

    2003-01-01

    The National Atmospheric Deposition Program, a cooperative effort supported by Federal, State, and local agencies, and Indian Tribes, was established in 1977 to study atmospheric deposition and its impact on the environment. The program's National Trends Network now includes wet-deposition networks at more than 250 sites across the United States, Canada, Puerto Rico, and the Virgin Islands. Precipitation amounts are currently measured using a Belfort Universal Precipitation Gage 5-780, which involves technology that is more than 50 years old. In 1999, a three-phase study was begun to evaluate several weighing, all-weather precipitation gages to find a possible replacement for the Belfort Universal Precipitation Gage 5-780. One gage that performed consistently well in phase I and II testing was the OTT PLUVIO Precipitation Gage. Phase III of the study, discussed herein, was to determine the accuracy and comparability of the data sets collected by the OTT PLUVIO Precipitation Gages and the existing Belfort Universal Precipitation Gage 5-780. Seven OTT PLUVIO Precipitation Gages were installed at six National Trends Network sites across the country for a data-collection period of approximately 18 months. The NovaLynx Model 260-2510 Standard Rain and Snow Gage also was used, as a reference, at two of the sites. Paired t-tests analysis showed no significant differences in precipitation measurements between the Belfort Universal Precipitation Gage 5-780 and the OTT PLUVIO Precipitation Gages at three of the six sites. When the false positives were removed from the precipitation-event data sets, the gages at all sites were in agreement and the paired t-tests showed the gage measurements were not significantly different. A false positive is defined as a zero response from the Belfort Universal Precipitation Gage 5-780 concurrent with a recorded response from the OTT PLUVIO Precipitation Gage.

  16. Main features associated to the precipitation in Madeira and the Atmospheric rivers in the winter seasons.

    OpenAIRE

    Couto, Flavio; Salgado, Rui; Costa, Maria João

    2015-01-01

    This study presents the main features about 10-year daily accumulated precipitation analysis over the Madeira's highlands, as well as the relationships between this precipitation and the meridional water vapor transport occurring in narrow corridors, also known as atmospheric rivers (ARs). The ARs were visually identified in the total precipitable water vapor field extracted from the Atmospheric Infrared Sounder (AIRS) data, and over a domain covering the North Atlantic Ocean. When needed,...

  17. Source of atmospheric moisture and precipitation over China's major river basins

    Science.gov (United States)

    Zhao, Tongtiegang; Zhao, Jianshi; Hu, Hongchang; Ni, Guangheng

    2016-03-01

    Oceanic evaporation via the East Asian Monsoon (EAM) has been regarded as the major source of precipitation over China, but a recent study estimated that terrestrial evaporation might contribute up to 80% of the precipitation in the country. To explain the contradiction, this study presents a comprehensive analysis of the contribution of oceanic and terrestrial evaporation to atmospheric moisture and precipitation in China's major river basins. The results show that from 1980 to 2010, the mean annual atmospheric moisture (precipitable water) over China was 13.7 mm, 39% of which originates from oceanic evaporation and 61% from terrestrial evaporation. The mean annual precipitation was 737 mm, 43% of which originates from oceanic evaporation and 57% from terrestrial evaporation. Oceanic evaporation makes a greater contribution to atmospheric moisture and precipitation in the East Asian Monsoon Region in South and East China than terrestrial evaporation does. Particularly, for the Pearl River and southeastern rivers, oceanic evaporation contributes approximately 65% of annual precipitation and more than 70% of summer precipitation. Meanwhile, terrestrial evaporation contributes more precipitation in northwest China due to the westerly wind. For the northwestern rivers, terrestrial evaporation from the Eurasian continents contributes more than 70% of precipitation. There is a linear relation between mean annual precipitation and the contribution of oceanic evaporation to precipitation, with a correlation coefficient of 0.92, among the ten major river basins in China.

  18. Source of atmospheric moisture and precipitation over China's major river basins

    Institute of Scientific and Technical Information of China (English)

    Tongtiegang ZHAO; Jianshi ZHAO; Hongchang HU; Guangheng NI

    2016-01-01

    Oceanic evaporation via the East Asian Monsoon (EAM) has been regarded as the major source of precipitation over China,but a recent study estimated that terrestrial evaporation might contribute up to 80% of the precipitation in the country.To explain the contradiction,this study presents a comprehensive analysis of the contribution of oceanic and terrestrial evaporation to atmospheric moisture and precipitation in China's major river basins.The results show that from 1980 to 2010,the mean annual atmospheric moisture (precipitable water) over China was 13.7 mm,39% of which originates from oceanic evaporation and 61% from terrestrial evaporation.The mean annual precipitation was 737 mm,43% of which originates from oceanic evaporation and 57% from terrestrial evaporation.Oceanic evaporation makes a greater contribution to atmospheric moisture and precipitation in the East Asian Monsoon Region in South and East China than terrestrial evaporation does.Particularly,for the Pearl River and southeastern rivers,oceanic evaporation contributes approximately 65% of annual precipitation and more than 70% of summer precipitation.Meanwhile,terrestrial evaporation contributes more precipitation in northwest China due to the westerly wind.For the northwestern rivers,terrestrial evaporation from the Eurasian continents contributes more than 70% of precipitation.There is a linear relation between mean annual precipitation and the contribution of oceanic evaporation to precipitation,with a correlation coefficient of 0.92,among the ten major river basins in China.

  19. Evaluating the extreme precipitation events using a mesoscale atmosphere model and satellite based precipitation product

    Directory of Open Access Journals (Sweden)

    I. Yucel

    2013-12-01

    Full Text Available Quantitative precipitation estimates are obtained with more uncertainty under the influence of changing climate variability and complex topography from numerical weather prediction (NWP models. On the other hand, hydrologic model simulations depend heavily on the availability of reliable precipitation estimates. Difficulties in estimating precipitation impose an important limitation on the possibility and reliability of hydrologic forecasting and early warning systems. This study examines the performance of the Weather Research and Forecasting (WRF model and the Multi Precipitation Estimates (MPE algorithm in producing the temporal and spatial characteristics of the number of extreme precipitation events observed in the West Black Sea Region of Turkey. Precipitations derived from WRF model with and without three-dimensional variational (3-DVAR data assimilation scheme and MPE algorithm at high spatial resolution (4 km are compared with gauge precipitation. WRF-derived precipitation showed capabilities in capturing the timing of precipitation extremes and in some extent the spatial distribution and magnitude of the heavy rainfall events wheras MPE showed relatively weak skills in these aspects. WRF skills in estimating such precipitation characteristics are enhanced with the application of 3-DVAR scheme. Direct impact of data assimilation on WRF precipitation reached to 12% and at some points there exists quantitative match for heavy rainfall events, which are critical for hydrological forecast.

  20. Atmospheric ionization induced by precipitating electrons: Comparison of CRAC:EPII model with parametrization model

    CERN Document Server

    Artamonov, A A; Usoskin, I G

    2016-01-01

    A new model CRAC:EPII (Cosmic Ray Atmospheric Cascade: Electron Precipitation Induced Ionization) is presented. The CRAC:EPII is based on Monte Carlo simulation of precipitating electrons propagation and interaction with matter in the Earth atmosphere. It explicitly considers energy deposit: ionization, pair production, Compton scattering, generation of Bremsstrahlung high energy photons, photo-ionization and annihilation of positrons, multiple scattering as physical processes accordingly. The propagation of precipitating electrons and their interactions with atmospheric molecules is carried out with the GEANT4 simulation tool PLANETOCOSMICS code using NRLMSISE 00 atmospheric model. The ionization yields is compared with an analytical parametrization for various energies of incident precipitating electron, using a flux of mono-energetic particles. A good agreement between the two models is achieved. Subsequently, on the basis of balloon-born measured spectra of precipitating electrons at 30.10.2002 and 07.01....

  1. Downscaling atmospheric patterns to multi-site precipitation amounts in southern Scandinavia

    DEFF Research Database (Denmark)

    Gelati, Emiliano; Christensen, O.B.; Rasmussen, P.F.;

    2010-01-01

    A non-homogeneous hidden Markov model (NHMM) is applied for downscaling atmospheric synoptic patterns to winter multi-site daily precipitation amounts. The implemented NHMM assumes precipitation to be conditional on a hidden weather state that follows a Markov chain, whose transition probabilities......-varying with precipitation. We assume the common hidden weather state process to completely account for the temporal structure of precipitation. Given the current weather state, the multivariate probability distribution of precipitation occurrences is approximated using a Chow-Liu tree dependence structure, involving...

  2. Retrieving Atmospheric Precipitable Water Vapor Using Artificial Neural Network Approach

    Directory of Open Access Journals (Sweden)

    Wang Xin

    2013-07-01

    Full Text Available Discussing of water vapor and its variation is the important issue for synoptic meteorology and meteorology. In physical Atmospheric, the moisture content of the earth atmosphere is one of the most important parameters, it is hard to represent water vapor because of its space-time variation. High-spectral resolution Atmospheric Infrared Sounder (AIRS data can be used to retrieve the small scale vertical structure of air temperature, which provided a more accurate and good initial field for the numerical forecasting and the large-scale weather analysis. This paper proposes an artificial neural network to retrieve the clear sky atmospheric radiation data from AIRS and comparing with the AIRS Level-2 standard product, and gain a good inversion results.

  3. Future changes in atmospheric circulation types and related precipitation extremes in Central Europe

    Science.gov (United States)

    Homann, Markus; Jacobeit, Jucundus; Beck, Christoph; Philipp, Andreas

    2016-04-01

    The statistical evaluation of the relationships between atmospheric circulation types and areal precipitation events took place in the context of an international project called WETRAX (Weather patterns, storm tracks and related precipitation extremes). The aim of the project was to estimate the regional flooding potential in Central Europe under enhanced climate change conditions. For parts of southern Central Europe, a gridded daily precipitation set with 6km horizontal resolution has been generated for the period 1951-2006 by the Austrian Zentralanstalt für Meteorologie und Geodynamik (ZAMG). To determine regions with similar precipitation variability, a S-mode principal component analysis has been applied. Extreme precipitation events are defined by the 95% percentile, based on regional arithmetic means of daily precipitation. Large-scale atmospheric circulation types have been derived by different statistical methods and variables using the COST733 classification software and gridded daily NCEP1 reanalysis data. To evaluate the performance of a particular circulation type classification with respect to regional precipitation extremes, multiple regression models have been derived between the circulation type frequencies as predictor variables and monthly frequencies of extreme precipitation as well as monthly rainfall amounts from these events. To estimate the regional flooding potential in Central Europe under enhanced climate change conditions, multiple regression models are applied to different projected GCM predictor data. Thus, future changes in circulation type occurrence frequencies are transferred into assessments of future changes in precipitation extremes on a regional scale.

  4. Precipitation of Energetic Neutral Atoms and Induced Non-Thermal Escape Fluxes from the Martian Atmosphere

    CERN Document Server

    Lewkow, Nicholas

    2014-01-01

    The precipitation of energetic neutral atoms (ENAs), produced through charge exchange (CX) collisions between solar wind (SW) ions and thermal atmospheric gases, is investigated. Subsequent induced non-thermal escape fluxes have been carried out for the Martian atmosphere. Detailed modeling of the ENA energy input and determination of connections between parameters of precipitating ENAs and resulting escape fluxes, reflection coefficients of fast atoms from the Mars atmosphere, and altitude dependent ENA energy distributions are established using Monte Carlo (MC) simulations of the precipitation process with accurate quantum mechanical (QM) cross sections. Detailed descriptions of secondary hot (SH) atoms and molecules induced by ENAs have been obtained for a better understanding of the mechanisms responsible for atmospheric escape and evolution. The effects of using isotropic hard sphere (HS) cross sections as compared to realistic, anisotropic quantum cross sections are examined for energy-deposition profil...

  5. Precipitation of energetic neutral atoms and induced non-thermal escape fluxes from the Martian atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Lewkow, N. R.; Kharchenko, V. [Department of Physics, University of Connecticut, Storrs, CT 06269 (United States)

    2014-08-01

    The precipitation of energetic neutral atoms, produced through charge exchange collisions between solar wind ions and thermal atmospheric gases, is investigated for the Martian atmosphere. Connections between parameters of precipitating fast ions and resulting escape fluxes, altitude-dependent energy distributions of fast atoms and their coefficients of reflection from the Mars atmosphere, are established using accurate cross sections in Monte Carlo (MC) simulations. Distributions of secondary hot (SH) atoms and molecules, induced by precipitating particles, have been obtained and applied for computations of the non-thermal escape fluxes. A new collisional database on accurate energy-angular-dependent cross sections, required for description of the energy-momentum transfer in collisions of precipitating particles and production of non-thermal atmospheric atoms and molecules, is reported with analytic fitting equations. Three-dimensional MC simulations with accurate energy-angular-dependent cross sections have been carried out to track large ensembles of energetic atoms in a time-dependent manner as they propagate into the Martian atmosphere and transfer their energy to the ambient atoms and molecules. Results of the MC simulations on the energy-deposition altitude profiles, reflection coefficients, and time-dependent atmospheric heating, obtained for the isotropic hard sphere and anisotropic quantum cross sections, are compared. Atmospheric heating rates, thermalization depths, altitude profiles of production rates, energy distributions of SH atoms and molecules, and induced escape fluxes have been determined.

  6. Effect of atmospheric precipitation on the dissolved loads of the Dongjiang River,China

    Institute of Scientific and Technical Information of China (English)

    LI Jing-ying; ZHANG Jing

    2004-01-01

    The atmospheric precipitation plays an important role in influencing the river chemistry of the Dongjiang River. The atmospheric contribution to river water is estimated by reference to Cl concentration called Clref. The Clref of 41.97 μmol/L represents the highest chloride concentration of the rainwater inputs to river water, thus sea salts are responsible for total Cl concentration of the Dongjiang River. According to the principal compositions of precipitation and river water, we propose two approaches-sea salt correction and precipitation correction in order to correct the contribution proportions of atmospheric precipitation on the solutes and to calculate chemical weathering rate. The results reflected that the atmospheric contribution ratios fluctuate from ~5% to ~20% of TDS(total dissolved solids) in the Dongjiang River. As compared with the other world watersheds, the lower dissolved ion contents and high runoff may result in the obvious influence of precipitation on river chemistry in the Dongjiang basin. The major elemental chemistry is mainly controlled by silicate weathering, with the anion HCO3- and cation Ca2+ and Na+ dominating the major compositions in this basin. The estimated chemical weathering rate of 15.78-23.48 t/(km2·a) is only 40%-60% of a global average in the Dongjiang basin. Certainly, the estimated results are still under correction gradually because the effect of human activities on the precipitation chemistry has never been quantified in detail.

  7. Precipitation in Madeira island and atmospheric rivers in the winter seasons

    Science.gov (United States)

    Couto, Flavio T.; Salgado, Rui; João Costa, Maria; Prior, Victor

    2016-04-01

    This study aims to analyse the distribution of the daily accumulated precipitation in the Madeira's highlands over a 10-year period, as well as the main characteristics associated with atmospheric rivers (ARs) affecting the island during 10 winter seasons, and their impact in the rainfall amounts recorded near the mountain crest in the south-eastern part of the island. The period between September 2002 and November 2012 is considered for the analysis. The ARs have been identified from the total precipitable water vapour field extracted from the Atmospheric Infrared Sounder (AIRS). The AIRS observations were downloaded for a domain covering large part of the North Atlantic Ocean. The precipitable water vapour field from the European Centre for Medium-range Weather Forecasts (ECMWF) analysis was also used aiming to support the AIRS data when there was no satellite information over the island. The daily accumulated precipitation at surface showed generally drier summers, while the highest accumulated precipitation are recorded mainly during the winter, although some significant events may occur also in autumn and spring seasons. The patterns of the precipitable water vapour field when ARs reach the island were investigated, and even if great part of the atmospheric rivers reaches the island in a dissipation stage, some rivers are heavy enough to reach the Madeira Island. In this situation, the water vapour transport could be observed in two main configurations and transporting significant water vapour amounts toward the Madeira from the tropical region. This study lead to conclude that the atmospheric rivers, when associated to high values of precipitable water vapour over the island can provide favourable conditions to the development of precipitation, sometimes associated with high amounts. However, it was also found that many cases of high to extreme accumulated precipitation at the surface were not associated to this kind of moisture transport.

  8. Changes in precipitation extremes projected by a 20-km mesh global atmospheric model

    Directory of Open Access Journals (Sweden)

    Akio Kitoh

    2016-03-01

    Full Text Available High-resolution modeling is necessary to project weather and climate extremes and their future changes under global warming. A global high-resolution atmospheric general circulation model with grid size about 20 km is able to reproduce climate fields as well as regional-scale phenomena such as monsoonal rainfall, tropical and extratropical cyclones, and heavy precipitation. This 20-km mesh model is applied to project future changes in weather and climate extremes at the end of the 21st century with four different spatial patterns in sea surface temperature (SST changes: one with the mean SST changes by the 28 models of the Coupled Model Intercomparison Project Phase 5 (CMIP5 under the Representative Concentration Pathways (RCP-8.5 scenario, and the other three obtained from a cluster analysis, in which tropical SST anomalies derived from the 28 CMIP5 models were grouped. Here we focus on future changes in regional precipitation and its extremes. Various precipitation indices averaged over the Twenty-two regional land domains are calculated. Heavy precipitation indices (maximum 5-day precipitation total and maximum 1-day precipitation total increase in all regional domains, even where mean precipitation decrease (Southern Africa, South Europe/Mediterranean, Central America. South Asia is the domain of the largest extreme precipitation increase. In some domains, different SST patterns result in large precipitation changes, possibly related to changes in large-scale circulations in the tropical Pacific.

  9. Uniform amorphous lactose microspheres formed in simultaneous convective and dehydration antisolvent precipitation under atmospheric conditions.

    Science.gov (United States)

    Mansouri, S; Fu, N; Woo, M W; Chen, X D

    2012-10-01

    A simultaneous convection-dehydration and antisolvent precipitation approach has been shown to produce uniform microsized lactose particles from aqueous droplet at atmospheric pressure. Microparticles with high uniformity having diameters of between 1.0 and 2.4 μm have been obtained. The precipitation of the microparticles is driven by a unique self-assembly mechanism that cannot be fully elucidated by supersaturation alone. Further analysis suggests that structural changes in the solvent/antisolvent mixture, due to hydrophobic hydration, could play a role in the precipitation process observed. PMID:22950653

  10. Interannual variability of the atmospheric CO2 growth rate: roles of precipitation and temperature

    Science.gov (United States)

    Wang, Jun; Zeng, Ning; Wang, Meirong

    2016-04-01

    The interannual variability (IAV) in atmospheric CO2 growth rate (CGR) is closely connected with the El Niño-Southern Oscillation. However, sensitivities of CGR to temperature and precipitation remain largely uncertain. This paper analyzed the relationship between Mauna Loa CGR and tropical land climatic elements. We find that Mauna Loa CGR lags precipitation by 4 months with a correlation coefficient of -0.63, leads temperature by 1 month (0.77), and correlates with soil moisture (-0.65) with zero lag. Additionally, precipitation and temperature are highly correlated (-0.66), with precipitation leading by 4-5 months. Regression analysis shows that sensitivities of Mauna Loa CGR to temperature and precipitation are 2.92 ± 0.20 PgC yr-1 K-1 and -0.46 ± 0.07 PgC yr-1 100 mm-1, respectively. Unlike some recent suggestions, these empirical relationships favor neither temperature nor precipitation as the dominant factor of CGR IAV. We further analyzed seven terrestrial carbon cycle models, from the TRENDY project, to study the processes underlying CGR IAV. All models capture well the IAV of tropical land-atmosphere carbon flux (CFTA). Sensitivities of the ensemble mean CFTA to temperature and precipitation are 3.18 ± 0.11 PgC yr-1 K-1 and -0.67 ± 0.04 PgC yr-1 100 mm-1, close to Mauna Loa CGR. Importantly, the models consistently show the variability in net primary productivity (NPP) dominates CGR, rather than heterotrophic respiration. Because previous studies have proved that NPP is largely driven by precipitation in tropics, it suggests a key role of precipitation in CGR IAV despite the higher CGR correlation with temperature. Understanding the relative contribution of CO2 sensitivity to precipitation and temperature has important implications for future carbon-climate feedback using such ''emergent constraint''.

  11. Atmospheric controls on Puerto Rico precipitation using artificial neural networks

    Science.gov (United States)

    Ramseyer, Craig A.; Mote, Thomas L.

    2016-01-01

    The growing need for local climate change scenarios has given rise to a wide range of empirical climate downscaling techniques. One of the most critical decisions in these methodologies is the selection of appropriate predictor variables for the downscaled surface predictand. A systematic approach to selecting predictor variables should be employed to ensure that the most important variables are utilized for the study site where the climate change scenarios are being developed. Tropical study areas have been far less examined than mid- and high-latitudes in the climate downscaling literature. As a result, studies analyzing optimal predictor variables for tropics are limited. The objectives of this study include developing artificial neural networks for six sites around Puerto Rico to develop nonlinear functions between 37 atmospheric predictor variables and local rainfall. The relative importance of each predictor is analyzed to determine the most important inputs in the network. Randomized ANNs are produced to determine the statistical significance of the relative importance of each predictor variable. Lower tropospheric moisture and winds are shown to be the most important variables at all sites. Results show inter-site variability in u- and v-wind importance depending on the unique geographic situation of the site. Lower tropospheric moisture and winds are physically linked to variability in sea surface temperatures (SSTs) and the strength and position of the North Atlantic High Pressure cell (NAHP). The changes forced by anthropogenic climate change in regional SSTs and the NAHP will impact rainfall variability in Puerto Rico.

  12. Precipitation characteristics for the Slovak republic and their link to the atmospheric circulation

    Science.gov (United States)

    Pokorná, Lucie; Pecho, Jozef; Faško, Pavol

    2013-04-01

    Slovak Republic is situated in the centre of Europe. Its terrain is rugged and altitude increases from the southern lowlands to mountains in the northeastern and northern parts of the region where it reaches more than 2000 m a. s. l. Precipitation in this region is affected by atmospheric systems coming from the Atlantic ocean (western direction) on one hand and from the Mediterranean on the other hand (southern direction). However cyclones passing the Baltic Sea play a significant role determining precipitation occurrence and amounts as well. All these factors together with local effects lead to three different precipitation regimes in Slovakia: (i) Continental (with low precipitation in winter and the highest in summer), (ii) Atlantic (with equally distributed precipi¬tation all year round) and (iii) Mediterranean (with highest pre¬cipitation in June or May and secon¬dary maximum in October-December). The Mediterranean regime is more pronounced in the southern part of Central Slovakia while the Continental in the northeastern Slovakia. In the contribution we focus on distribution of precipitation amounts during the year and on trends in occurrence of extreme precipitation and droughts. Series from 50 meteorological stations in the Slovak Republic from the period 1951, resp. 1961-2010, are used. The sub-regions with typical annual courses of precipitation are identified using cluster analysis. The temporal behaviour of mean precipitation totals during the second half of the 20th century is characterized by a significant decrease until the mid-1990s followed by an increase up to the present. The increase of precipitation totals is registered mainly in winter, and partly also in spring and autumn. Nevertheless the increase is not regular; short periods with heavy precipi-tation as well as longer and more severe drought spells have occurred more frequently in two recent decades. In the second part of this work, the influence of atmospheric circulation on

  13. Precipitation recycling in West Africa - regional modeling, evaporation tagging and atmospheric water budget analysis

    Science.gov (United States)

    Arnault, Joel; Kunstmann, Harald; Knoche, Hans-Richard

    2015-04-01

    Many numerical studies have shown that the West African monsoon is highly sensitive to the state of the land surface. It is however questionable to which extend a local change of land surface properties would affect the local climate, especially with respect to precipitation. This issue is traditionally addressed with the concept of precipitation recycling, defined as the contribution of local surface evaporation to local precipitation. For this study the West African monsoon has been simulated with the Weather Research and Forecasting (WRF) model using explicit convection, for the domain (1°S-21°N, 18°W-14°E) at a spatial resolution of 10 km, for the period January-October 2013, and using ERA-Interim reanalyses as driving data. This WRF configuration has been selected for its ability to simulate monthly precipitation amounts and daily histograms close to TRMM (Tropical Rainfall Measuring Mission) data. In order to investigate precipitation recycling in this WRF simulation, surface evaporation tagging has been implemented in the WRF source code as well as the budget of total and tagged atmospheric water. Surface evaporation tagging consists in duplicating all water species and the respective prognostic equations in the source code. Then, tagged water species are set to zero at the lateral boundaries of the simulated domain (no inflow of tagged water vapor), and tagged surface evaporation is considered only in a specified region. All the source terms of the prognostic equations of total and tagged water species are finally saved in the outputs for the budget analysis. This allows quantifying the respective contribution of total and tagged atmospheric water to atmospheric precipitation processes. The WRF simulation with surface evaporation tagging and budgets has been conducted two times, first with a 100 km2 tagged region (11-12°N, 1-2°W), and second with a 1000 km2 tagged region (7-16°N, 6°W -3°E). In this presentation we will investigate hydro-atmospheric

  14. Laser-assisted water condensation in the atmosphere: a step towards modulating precipitation?

    International Nuclear Information System (INIS)

    We review the recent results about laser-induced condensation based on self-guided filaments generated by ultrashort laser pulses. After recalling the physico-chemistry of cloud particle formation in the atmosphere and the physics of laser filamentation, we discuss experimental results on laser-induced condensation and its relevance for modulating precipitation. (topical review)

  15. A comparison of Lagrangian precipitation statistics computed with two regional-scale atmospheric transport models

    Energy Technology Data Exchange (ETDEWEB)

    Dittenhoefer, A.C.; Ferullo, A.F.

    1984-01-01

    In an earlier paper the authors pointed out that air mass trajectories computed from winds on an isobaric surface or winds averaged throughout a fixed layer were inappropriate for regional-scale acid deposition studies. This is because isobaric and fixed layer models do not adequately treat vertical motions and wind shears that occur during long range transport associated with precipitation. To improve the vertical resolution of regional-scale transport simulations and to more accurately account for large-scale vertical motions and wind shears during thermodynamically stable atmospheric conditions, they developed the enviroplan dual-mode regional air back-trajector model (EDRAB). In this paper they compute Lagrangian precipitation statistics for an entire year of precipitation events at Whiteface Mountain, New York using EDRAB and the widely used NOAA air resources laboratories atmospheric transport and dispersion model (ARL-ATAD).

  16. Sampling of Atmospheric Aerosols by Electrostatic Precipitation for Direct Analyses. Part 1

    CERN Document Server

    Hermann, G; Matz, R; Trenin, A; Moritz, W; Hermann, Gerd; Lasnitschka, Georg; Matz, Rudolf; Trenin, Alexander; Moritz, Walter

    2002-01-01

    A novel system for aerosol sampling by electrostatic precipitation using graphite platforms as sample collector is presented. Employing standard platforms for commercial analytical instruments, the conception allows fast solid sampling direct element analysis with ETAAS, ETV-ICP-MS/OES, and ETACFS without any wet digestive pre-treatment. Other advantages are: highly efficient electrostatic particle collection (>99% for d = 10e-9 m - 10e-6 m), reusable sample collectors, omission of filters and chemical reagents. On this basis, an electrostatic precipitator is constructed aiming at a small, relatively uncomplicated instrument. Ten precipitators are arranged in a multi-sampling apparatus for outdoor operation, which simultaneously collect ten samples on same or different collectors for instrumental element analyses, or for microscopic investigations of the collected particles. The precipitator is tested with different model aerosols as well as with atmospheric sampling. Element analysis is carried out with the ...

  17. Sampling of Atmospheric Aerosols by Electrostatic Precipitation for Direct Analyses. Part 2

    CERN Document Server

    Hermann, G; Matz, R; Trenin, A; Moritz, W; Hermann, Gerd; Lasnitschka, Georg; Matz, Rudolf; Trenin, Alexander; Moritz, Walter

    2002-01-01

    A novel system for aerosol sampling by electrostatic precipitation using graphite platforms as sample collector is presented. Employing standard platforms for commercial analytical instruments, the conception allows fast solid sampling direct element analysis with ETAAS, ETV-ICP-MS/OES, and ETACFS without any wet digestive pre-treatment. Other advantages are: highly efficient electrostatic particle collection (>99% for d = 10e-9 m - 10e-6 m), reusable sample collectors, omission of filters and chemical reagents. On this basis, an electrostatic precipitator is constructed aiming at a small, relatively uncomplicated instrument. Ten precipitators are arranged in a multi-sampling apparatus for outdoor operation, which simultaneously collect ten samples on same or different collectors for instrumental element analyses, or for microscopic investigations of the collected particles. The precipitator is tested with different model aerosols as well as with atmospheric sampling. Element analysis is carried out with the ...

  18. Trends in atmospheric patterns conducive to seasonal precipitation and temperature extremes in California.

    Science.gov (United States)

    Swain, Daniel L; Horton, Daniel E; Singh, Deepti; Diffenbaugh, Noah S

    2016-04-01

    Recent evidence suggests that changes in atmospheric circulation have altered the probability of extreme climate events in the Northern Hemisphere. We investigate northeastern Pacific atmospheric circulation patterns that have historically (1949-2015) been associated with cool-season (October-May) precipitation and temperature extremes in California. We identify changes in occurrence of atmospheric circulation patterns by measuring the similarity of the cool-season atmospheric configuration that occurred in each year of the 1949-2015 period with the configuration that occurred during each of the five driest, wettest, warmest, and coolest years. Our analysis detects statistically significant changes in the occurrence of atmospheric patterns associated with seasonal precipitation and temperature extremes. We also find a robust increase in the magnitude and subseasonal persistence of the cool-season West Coast ridge, resulting in an amplification of the background state. Changes in both seasonal mean and extreme event configurations appear to be caused by a combination of spatially nonuniform thermal expansion of the atmosphere and reinforcing trends in the pattern of sea level pressure. In particular, both thermal expansion and sea level pressure trends contribute to a notable increase in anomalous northeastern Pacific ridging patterns similar to that observed during the 2012-2015 California drought. Collectively, our empirical findings suggest that the frequency of atmospheric conditions like those during California's most severely dry and hot years has increased in recent decades, but not necessarily at the expense of patterns associated with extremely wet years. PMID:27051876

  19. Regional atmospheric circulation over Europe during the Last Glacial Maximum and its links to precipitation

    Science.gov (United States)

    Ludwig, Patrick; Schaffernicht, Erik J.; Shao, Yaping; Pinto, Joaquim G.

    2016-03-01

    The Last Glacial Maximum (LGM) exhibits different large-scale atmospheric conditions compared to present-day climate due to altered boundary conditions. The regional atmospheric circulation and associated precipitation patterns over Europe are characterized for the first time with a weather typing approach (circulation weather types, CWT) for LGM paleoclimate simulations. The CWT approach is applied to four representative regions across Europe. While the CWTs over Western Europe are prevailing westerly for both present-day and LGM conditions, considerable differences are identified elsewhere: Southern Europe experienced more frequent westerly and cyclonic CWTs under LGM conditions, while Central and Eastern Europe was predominantly affected by southerly and easterly flow patterns. Under LGM conditions, rainfall is enhanced over Western Europe but is reduced over most of Central and Eastern Europe. These differences are explained by changing CWT frequencies and evaporation patterns over the North Atlantic Ocean. The regional differences of the CWTs and precipitation patterns are linked to the North Atlantic storm track, which was stronger over Europe in all considered models during the LGM, explaining the overall increase of the cyclonic CWT. Enhanced evaporation over the North Atlantic leads to higher moisture availability over the ocean. Despite the overall cooling during the LGM, this explains the enhanced precipitation over southwestern Europe, particularly Iberia. This study links large-scale atmospheric dynamics to the regional circulation and associated precipitation patterns and provides an improved regional assessment of the European climate under LGM conditions.

  20. Mechanisms Controlling the Annual Cycle of Precipitation in the Tropical Atlantic Sector in an Atmospheric GCM(.

    Science.gov (United States)

    Biasutti, M.; Battisti, D. S.; Sarachik, E. S.

    2004-12-01

    A set of AGCM experiments is used to study the annual cycle of precipitation in the region surrounding the tropical Atlantic Ocean. The experiments are designed to reveal the relative importance of insolation over land and the (uncoupled) SST on the annual cycle of precipitation over the tropical Atlantic Ocean, Africa, and the tropical Americas.SST variations impact the position of the maritime ITCZ by forcing the hydrostatic adjustment of the atmospheric boundary layer and changes in surface pressure and low-level convergence. The condensation heating released in the ITCZ contributes substantially to the surface circulation and the maintenance of the SST-induced ITCZ anomalies.The remote influence of SST is felt in equatorial coastal areas and the Sahel. The circulation driven by condensation heating in the maritime ITCZ extends to the coastal regions, thus communicating the SST signal onshore. Conversely, the Sahel responds to variations in SST through boundary layer processes that do not involve the maritime ITCZ. The atmospheric response to changes in subtropical SST is advected inland and forces changes in sea level pressure and low-level convergence across a large part of tropical Africa.The impact of local insolation on continental precipitation can be explained by balancing net energy input at the top of the atmospheric column with the export of energy by the divergent circulation that accompanies convection. Increased insolation reduces the stability of the atmosphere in the main continental convection centers, but not in monsoon regions.Insolation over land impacts the intensity of the maritime ITCZ via its influence on precipitation in Africa and South America. Reduced land precipitation induces the cooling of the Atlantic upper troposphere and the enhancement of convective available potential energy in the maritime ITCZ.

  1. Precipitation-climate sensitivity to initial conditions in an atmospheric general circulation model

    Energy Technology Data Exchange (ETDEWEB)

    Covey, C., LLNL

    1997-03-01

    Atmospheric climate, in contrast to weather, is traditionally considered to be determined by boundary conditions such as sea surface temperature (SST). To test this hypothesis, we examined annual mean precipitation from an ensemble of 20 general circulation model (GCM) simulations. Ensemble members were forced with identical 10-year series of SST and sea ice, but they began with slightly differing initial conditions. A surprisingly small proportion of the variance in the output is attributable to the effects of boundary forcing. This result-and similar evidence from smaller ensembles of other GCM simulations-implies that long-term precipitation variations are mostly unpredictable, even if SST forecasts are `perfect.`

  2. Quantifying Future Changes in Extreme Precipitation Events Based on Resolved Synoptic Atmospheric Patterns

    Science.gov (United States)

    Gao, X.; Schlosser, C. A.; Monier, E.; Entekhabi, D.

    2012-12-01

    An important question for climate change science is possible shifts in the extremes of regional water cycle, especially changes in patterns, intensity and/or frequency of extreme precipitation events. In this study, an analogue method is developed to help detect extreme precipitation events and their potential changes under future climate regimes without relying on the highly uncertain modeled precipitation. Our approach is based on the use of composite maps to identify the distinct synoptic and large-scale atmospheric conditions that lead to extreme precipitation events at local scales. The analysis of extreme daily precipitation events, exemplified in the south-central United States, is carried out using 62-yr (1948-2010) CPC gridded station data and NASA's Modern Era Retrospective-analysis for Research and Applications (MERRA). Various aspects of the daily extremes are examined, including their historical ranking, associated common circulation features at upper and lower levels of the atmosphere, and moisture plumes. The scheme is first evaluated for the multiple climate model simulations of the 20th century from Coupled Model Intercomparison Project Phase 5 (CMIP5) archive to determine whether the statistical nature of modeled precipitation events (i.e. the numbers of occurrences over each season) could well correspond to that of the observed. Further, the approach will be applied to the CMIP5 multi-model projections of various climate change scenarios (i.e. Representative Concentration Pathways (RCP) scenarios) in the next century to assess the potential changes in the probability of extreme precipitation events. The research results from this study should be of particular significance to help society develop adaptive strategies and prevent catastrophic losses.

  3. The response of oxygen isotope ratios in precipitation to changes in global atmospheric circulation

    International Nuclear Information System (INIS)

    Full text: Stable isotopes of oxygen and hydrogen present in water are known to undergo fractionation at phase transitions, with heavy isotopes tending to evaporate less readily and to undergo condensation more readily than lighter isotopes. The combination of fractionation processes for a given air parcel therefore produces the known relationships between precipitation amount, surface temperature and the isotopic ratio in precipitation. An additional factor in determining the isotopic ratio is the effect of changes in vapour source region and vapour path due to changes in atmospheric circulation. In order to explore the effect of changes in circulation related to El Nino/Southern Oscillation (ENSO) events, an atmospheric general circulation model fitted with a diagnostic module to predict the stable isotopic ratios of meteoric water (both HDO and H218O) is used to investigate the effect of warm sea surface temperature (SST) anomalies on moisture transport and hence on isotopic ratios in precipitation. Observed isotopic ratios obtained from the Global Network of Isotopes in Precipitation (GNIP) are also correlated with Troup SOI values and compared with the model results. Copyright (1999) Geological Society of Australia

  4. ATMOSPHERIC TRANSPORT TO THE GAW REGIONAL STATION AT ZAVIŽAN AND RELATED PRECIPITATION CHEMISTRY

    OpenAIRE

    Bajić, Alica

    2001-01-01

    Abstract: A study on the connection between the state of the atmosphere, as represented by cluster-mean trajectories, and the chemical composition of precipitation at the Croatian GAW regional station of Zavižan is presented. The trajectory cluster analysis has been done on the basis of daily backward trajectories calculated for 1996, using the HYSPLIT_4 trajectory model. The seasonal cluster analysis indicates four major flow directions in the region: 1) fast W-NW flow, 2) strong SW flow,...

  5. Quantifying the relationship between atmospheric transport and the chemical composition of precipitation on Bermuda

    OpenAIRE

    Moody, Jennie L.; Galloway, James N.

    2011-01-01

    In an effort to investigate the influence of different atmospheric flow patterns on thecomposition of precipitation on the island of Bermuda, a cluster analysis of atmospherictrajectories was performed to identify periods of similar transport. The cluster analysistechnique represents a relatively objective alternative to the more subjective method ofclassifying trajectories according to compass sector. Data were stratified into two broadseasons, defined as a warm (April-September) and a cool ...

  6. Features of the flux of gamma-radiation in the lower atmosphere during precipitation

    International Nuclear Information System (INIS)

    We are carrying out observations and studies of increases of gamma radiation intensity in a ground atmosphere layer during precipitations. Measurements have been carried out in two high-altitude points: Apatity (Murmansk) and Barentsburg (Spitsbergen). Scintillation detectors on the basis of NaI(Tl) crystals are used. Continuous radiation detection is made as the count rate in integral channels with threshold values >20 keV, >100 keV. There are more than 500 events of increase in gamma-ray background during precipitation. Average profiles of X-ray radiation increases in a ground level and the related with them increases of intensity of precipitations for stations in Apatity and Barentsburg have been built up. In Apatity the average increase profile in the gamma-ray flux and accompanying with profile of precipitations rate have been obtained. A time gap between peaks of precipitation and increase one is 30-40 minutes. A barometric coefficient of each component of radiation has been calculated. The barometric coefficient has a zero value on gamma-ray. The charged component of the secondary cosmic rays has a typical value ∼0.18 %/mB. The lack of the barometric effect on gamma-ray indicates on the local origin of this radiation.

  7. Atmospheric circulation controls on the inter-annual variability in precipitation isotope ratio in Japan

    Directory of Open Access Journals (Sweden)

    N. Kurita

    2014-10-01

    Full Text Available This study explored the primary driver of variations of precipitation isotopes at multiple temporal scales (event, seasonal and inter-annual scales to provide a greater depth of interpretation for isotope proxy records in Japan. A one-year record of the isotopic composition of event-based precipitation at Nagoya in central Japan showed less seasonal variation, but there is large isotopic variability on a storm-to-storm basis. In the summer, southerly flows transport isotopically enriched moisture from subtropical marine regions with the result that the rainfall produced by the subtropical air, or warm rainfall, was relatively enriched in heavy isotopes in comparison with the other rainfall events. In the winter, storm tracks are the dominant driver of storm-to-storm isotopic variation, and relatively lower isotopic values occurred when northerly winds in association with extratropical cyclones passing off the south coast of Japan (Nangan cyclone brings cold precipitation. Using the historical 17 year record of monthly isotopes in precipitation at Tokyo station, we explored if the factors controlling event-scale isotopic variability can account for inter-annual isotopic variability. The relatively higher isotopes in summer precipitation were attributed to the higher contribution of the warm rainfall to the total summer precipitation. On the other hand, year-to-year variation of isotopic values in winter precipitation was negatively correlated with the relative ratio of the Nangan cyclone rainfall to the total winter precipitation. The 17 year precipitation history demonstrates that event-scale isotopic variability related to changes in meridional moisture transport is the primary driver of inter-annual isotopic variability in winter and summer precipitation. The meridional moisture transport to central Japan is likely linked to the activity of the western North Pacific subtropical high in summer and the intensity of the East Asian winter monsoon

  8. Atmospheric response to Indian Ocean Dipole forcing: changes of Southeast China winter precipitation under global warming

    Science.gov (United States)

    Zhang, Ling; Sielmann, Frank; Fraedrich, Klaus; Zhi, Xiefei

    2016-05-01

    To investigate the relationship between autumn Indian Ocean Dipole (IOD) events and the subsequent winter precipitation in Southeast China (SEC), observed fields of monthly precipitation, sea surface temperature (SST) and atmospheric circulation are subjected to a running and a maximum correlation analysis. The results show a significant change of the relevance of IOD for the early modulation of SEC winter precipitation in the 1980s. After 1980, positive correlations suggest prolonged atmospheric responses to IOD forcing, which are linked to an abnormal moisture supply initiated in autumn and extended into the subsequent winter. Under global warming two modulating factors are relevant: (1) an increase of the static stability has been observed suppressing vertical heat and momentum transports; (2) a positive (mid-level) cloud-radiation feedback jointly with the associated latent heating (apparent moisture sink Q2) explains the prolongation of positive as well as negative SST anomalies by conserving the heating (apparent heat source Q1) in the coupled atmosphere-ocean system. During the positive IOD events in fall (after 1980) the dipole heating anomalies in the middle and lower troposphere over the tropical Indian Ocean are prolonged to winter by a positive mid-level cloud-radiative feedback with latent heat release. Subsequently, thermal adaptation leads to an anticyclonic anomaly over Eastern India overlying the anomalous cooling SST of the tropical Eastern Indian Ocean enhancing the moisture flow from the tropical Indian Ocean through the Bay of Bengal into South China, following the northwestern boundary of the anticyclonic circulation anomaly over east India, thereby favoring abundant precipitation in SEC.

  9. Synoptic patterns of atmospheric circulation associated with intense precipitation events over the Brazilian Amazon

    Science.gov (United States)

    Santos, Eliane Barbosa; Lucio, Paulo Sérgio; Santos e Silva, Cláudio Moisés

    2015-12-01

    The objective of this study is to characterize the atmospheric patterns associated with the occurrence of intense precipitation events (IPE) in different sub-regions of the Brazilian Amazon. Intense rainfall cases over six sub-regions were selected from a precipitation data set for the period from 1983 to 2012. The composition technique was used to characterize the prevailing atmospheric patterns for the occurrence of IPE. In the south of the Amazon, the composition fields showed a favorable configuration for the formation of the South Atlantic Convergence Zone (SACZ). Along the coast, the intense precipitation events must be associated with mesoscale systems, such as squall lines. In the northwest, they are apparently associated with the Intertropical Convergence Zone (ITCZ) and/or local convection. The results reveal the complexity of the synoptic environment associated with the formation and development of weather systems that produce heavy rainfall in the Amazon Basin. Several factors can interfere as conditions in large-scale, local conditions and thermodynamic factors.

  10. Variability of Summer Atmospheric Moisture Flux and Its Effect on Precipitation over East China

    Institute of Scientific and Technical Information of China (English)

    JIANG Ying; ZHAI ranmao; WANG Qiyi

    2005-01-01

    Using the in-situ precipitation and NCEP/NCAR daily reanalysis data, we found by studies of change of moisture flux and its effect that the northward water vapor transport represented by moisture flux in East China tends to retreat southward, and the eastward water vapor transport tends to weaken with weakening of the intensity of moisture flux. The north boundary of meridional moisture flux (50 kg m-1s-1) retreats 2.8 degrees in latitude per decade during 1968-2003. The weakening of water vapor transport implies the weakening and southward retreat of East Asian monsoon, which leads to the tendency of decrease in moisture flux convergence over North China and the middle and lower reaches of the Yellow River, and the tendency of decrease in precipitation over those regions, but on the contrary the enhanced water vapor transport convergence over the middle and lower reaches of the Yangtze River implies the tendency of increase in precipitation to some extent. Indeed the long-term variability of precipitation in East China has a close relation with that of atmospheric moisture flux.

  11. Daily precipitation extreme events for the Iberian Peninsula and its association with Atmospheric Rivers

    Science.gov (United States)

    Ramos, Alexandre M.; Trigo, Ricardo M.; Liberato, Margarida LR

    2014-05-01

    Extreme precipitation events in the Iberian Peninsula during the extended winter months have major socio-economic impacts such as floods, landslides, extensive property damage and life losses. These events are usually associated with low pressure systems with Atlantic origin, although some extreme events in summer/autumn months can be linked to Mediterranean low pressure systems. Quite often these events are evaluated on a casuistic base and making use of data from relatively few stations. An objective method for ranking daily precipitation events is presented here based on the extensive use of the most comprehensive database of daily gridded precipitation available for the Iberian Peninsula (IB02) and spanning from 1950 to 2008, with a resolution of 0.2° (approximately 16 x 22 km at latitude 40°N), for a total of 1673 pixels. This database is based on a dense network of rain gauges, combining two national data sets, 'Spain02' for peninsular Spain and Balearic islands, and 'PT02' for mainland Portugal, with a total of more than two thousand stations over Spain and four hundred stations over Portugal, all quality-controlled and homogenized. Through this objective method for ranking daily precipitation events the magnitude of an event is obtained after considering the area affected as well as its intensity in every grid point and taking into account the daily precipitation normalised departure from climatology. Different precipitation rankings are presented considering the entire Iberian Peninsula, Portugal and also the six largest river basins in the Iberian Peninsula. Atmospheric Rivers (AR) are the water vapour (WV) core section of the broader warm conveyor belt occurring over the oceans along the warm sector of extra-tropical cyclones. They are usually W-E oriented steered by pre-frontal low level jets along the trailing cold front and subsequently feed the precipitation in the extra-tropical cyclones. They are relatively narrow regions of concentrated WV

  12. Use of POES SEM-2 observations to examine radiation belt dynamics and energetic electron precipitation into the atmosphere

    OpenAIRE

    Rodger, Craig J.; Clilverd, Mark A.; Green, Janet C.; Lam, Mai Mai

    2010-01-01

    The coupling of the Van Allen radiation belts to the Earth's atmosphere through precipitating particles is an area of intense scientific interest. Currently, there are significant uncertainties surrounding the precipitating characteristics of medium energy electrons (> 20 keV), and even more uncertainties for relativistic electrons. In this paper we examine roughly 10 years of measurements of trapped and precipitating electrons available from the Polar Orbiting Environmental Satellites (POES)...

  13. Middle atmospheric electrodynamic modification by particle precipitation at the South Atlantic magnetic anomaly

    Science.gov (United States)

    Gonzalez, W. D.; Dutra, S. L. G.; Pinto, O., Jr.

    1987-01-01

    Evidence for a localized middle atmospheric electrodynamic modification at low latitudes (southern Brazilian coast) of the South Atlantic Magnetic Anomaly (SAMA), in association with enhanced geomagnetic activity, are presented in a unified way combining recent observational efforts and related numerical studies. They involve a distortion effect in the fair weather electric field at balloon altitudes. This effect is attributed to a local intensification of energetic electron precipitation through a related middle atmospheric ionization enhancement and is elucidated by numeric simulation. From the electric field measurements and the numeric simulation, the intensification of precipitation is considered to occur in fairly narrow regions at the observed low L values (around L = 1.13) of the SAMA, with horizontal extensions of the order of a few hundred kilometers. A physical mechanism that could be responsible for this sort of intensification is suggested. Furthermore, a comparison of the phenomenon of middle atmospheric electrodynamic modification at the SAMA with a similar one at auroral latitudes, in response to enhanced solar and geomagnetic activity, is also given.

  14. POES SEM-2 observations of radiation belt dynamics and energetic electron precipitation in to the atmosphere

    International Nuclear Information System (INIS)

    Complete text of publication follows. The coupling of the Van Allen radiation belts to the Earth's atmosphere through the effects of precipitating particles is an area of intense scientific interest. Currently, there are significant uncertainties surrounding the precipitating characteristics of medium energy electrons (>20 keV), and even more uncertainties for relativistic electrons. In this paper we examine roughly ten-years of measurements of trapped and precipitating electrons available from the Polar Orbiting Environmental Satellites (POES)/Space Environment Monitor (SEM-2) which has provided long-term global data in this energy range. Relativistic electron increases are associated with both interplanetary Coronal Mass Ejections (ICMEs) and periodic high speed solar wind streams (HSSWS). The processes triggered by ICMEs are roughly twice as effective at enhancing POES-observed electrons to relativistic energies as the processes triggered by HSSWS. We find that ICME-associated increases can extend down to L∼2, while other enhancements are generally limited to L>3.5. Finally, during HSSWS conditions there is an energy-dependent time delay observed in the POES/SEM-2 observations, with the >800 keV relativistic electron enhancement delayed by ∼1-week relative to the >30 keV electron enhancement, probably due to the timescales of the acceleration processes. One possible interpretation of this is a two-stage process, where relatively rapid acceleration initially takes place near the geomagnetic equator as predicted by theory and observed experimentally. This is followed by a much slower process, where the relativistic electrons scatter towards the atmosphere loss cone at a rate which is energy dependent. Such large delays should have consequences for the timing of the atmospheric impact of HSSWS-triggered geomagnetic storms.

  15. Mean pH values of atmospheric precipitations in the selected countries in 1988 - 1992; 1 : 40 000 000; Mean pH values of atmospheric precipitations in the selected countries in 1995; 1 : 40 000 000

    International Nuclear Information System (INIS)

    The pH value of 5.6 corresponds to the natural acidity of precipitation water (equilibrium with the atmospheric CO2). In periods of the highest emissions of sulphur and nitrogen oxides (1980 - 1985) in Europe, the pH of precipitations in central and north-western Europe in average declined to 4. Sporadically extreme acid precipitations with pH of 3 occurred. Parallel to the decline of the European emissions, mainly in central and north-western Europe the decline of acidity of precipitation waters is observed. The return to the normal values in central and north-western Europe is expected before 2010. (author)

  16. Central-north China precipitation as reconstructed from the Qing dynasty: Signal of the Antarctic Atmospheric Oscillation

    Science.gov (United States)

    Wang, Huijun; Fan, Ke

    2005-12-01

    Based on the long-term Central-north China precipitation (CNCP) time series reconstructed from the Qing Dynasty Official Document, the relationship between CNCP and the Antarctic Atmospheric Oscillation (AAO) in June-July is examined. The analysis yields a (significant) negative correlation of -0.22. The signal of AAO in CNCP is further studied through analyses of the atmospheric general circulation variability related to AAO. It follows that AAO-related variability of convergence and convection over the tropical western Pacific can exert impact on the circulation condition and precipitation in north China (actually, the precipitation in the Yangtze River Valley as well) through atmospheric teleconnection known as the East Asia-Pacific (or Pacific-Japan) teleconnection wave pattern. There is also an AAO-connected wave train in the vorticity field at high troposphere over Eurasia, providing an anti-cyclonic circulation in central-north China favorable to the decline of precipitation in positive phase of AAO.

  17. THE QUANTITATIVE COMPONENT’S DIAGNOSIS OF THE ATMOSPHERIC PRECIPITATION CONDITION IN BAIA MARE URBAN AREA

    Directory of Open Access Journals (Sweden)

    S. ZAHARIA

    2012-12-01

    Full Text Available The atmospheric precipitation, an essential meteorological element for defining the climatic potential of a region, presents through its general and local particularities a defining influence for the evolution of the other climatic parameters, conditioning the structure of the overall geographic landscape. Their quantitative parameters sets up the regional natural setting and differentiation of water resources, soil, vegetation and fauna, in the same time influencing the majority of human activities’ aspects, through the generated impact over the agriculture, transportation, construction, for tourism etc. Especially, through the evolution of the related climatic parameters (production type, quantity, duration, frequency, intensity and their spatial and temporal fluctuations, the pluviometric extremes set out the maxim manifestation of the energy gap of the hydroclimatic hazards/risks which induce unfavourable or even damaging conditions for the human activities’ progress. Hence, the production of atmospheric precipitation surpluses conditions the triggering, or reactivation of some intense erosion processes, landslides, and last but not least, floods. Just as dangerous are the adverse amounts of precipitation or their absence on longer periods, determining the appearance of droughts, aridity phenomena, which if associated with the sharp anthropic pressure over the environment, favours the expansion of desertification, with the whole process of the arising negative effects. In this context, this paper aims to perform the diagnosis of atmospheric precipitation condition in Baia Mare urban area, through its quantitative component, in multiannual condition (1971-2007, underlining through the results of the analyzed climatic data and their interpretation, the main characteristics that define it. The data bank from Baia Mare station from the National Meteorological Administration network, representative for the chosen study area, was used. Baia

  18. Electric fields, electron precipitation, and VLF radiation during a simultaneous magnetospheric substorm and atmospheric thunderstorm

    International Nuclear Information System (INIS)

    A balloon payload instrumented with a double-probe electric field detector and an X ray scintillation counter was launched from Roberval, Quebec, Canada (L=4.1) at 0828 UT (0328 LT) on July 9, 1975. A magnetospheric substorm was observed locally between 0815 and 1100 UT, which produced a maximum ΔB of approx.500 nT at approx.0930 UT. A single-cell atmospheric thunderstorm developed northeast of Roberval beginning around 0925 UT which was most intense from approx.1000 to 1035 UT. Detailed study of the electrical properties of the thunderstorm, the X ray precipitation data, and VLF spheric data leads to three conclusions. First, the electrical coupling from the thunderstorm to the magnetosphere increases with frequency from dc to the VLF; for the observed storm the amplitude at the ionosphere of thunderstorm produced electric fields was not significant at frequencies below 0.1 Hz. Second, the atmospheric conductivity above the thunderstorm was observed to be about one-half the fair weather value prior to 1000 UT; decreased to about one-quarter the fair weather value at about 1000 UT; and remained depressed after the end of the thunderstorm. This result was contrary to that expected on the basis of previous work and is one which merits considerably more investigation. Third, the data show a high probability that half-hop whistlers initiated by sferics from the thunderstorm triggered energetic electron precipitation from the magnetosphere

  19. Atmospheric water vapor transport: Estimation of continental precipitation recycling and parameterization of a simple climate model. M.S. Thesis

    Science.gov (United States)

    Brubaker, Kaye L.; Entekhabi, Dara; Eagleson, Peter S.

    1991-01-01

    The advective transport of atmospheric water vapor and its role in global hydrology and the water balance of continental regions are discussed and explored. The data set consists of ten years of global wind and humidity observations interpolated onto a regular grid by objective analysis. Atmospheric water vapor fluxes across the boundaries of selected continental regions are displayed graphically. The water vapor flux data are used to investigate the sources of continental precipitation. The total amount of water that precipitates on large continental regions is supplied by two mechanisms: (1) advection from surrounding areas external to the region; and (2) evaporation and transpiration from the land surface recycling of precipitation over the continental area. The degree to which regional precipitation is supplied by recycled moisture is a potentially significant climate feedback mechanism and land surface-atmosphere interaction, which may contribute to the persistence and intensification of droughts. A simplified model of the atmospheric moisture over continents and simultaneous estimates of regional precipitation are employed to estimate, for several large continental regions, the fraction of precipitation that is locally derived. In a separate, but related, study estimates of ocean to land water vapor transport are used to parameterize an existing simple climate model, containing both land and ocean surfaces, that is intended to mimic the dynamics of continental climates.

  20. Atmospheric instability analysis and its relationship to precipitation patterns over the western Iberian Peninsula

    Directory of Open Access Journals (Sweden)

    S. Queralt

    2007-01-01

    Full Text Available Thermodynamic and dynamic atmospheric stability indices will be analysed in order to classify the rainfall types occurred in western Iberia and provide information about the associated meteorological phenomena and preferred regional instability sources. In this work, instability sources over the western Iberian Peninsula will be characterised by means of radiosonde station data and reanalysis data sets from the European Centre for Medium-Range Weather Forecasts (ECMWF, for the period 1971–2002. Dynamic stability indices such as the Q vector divergence (dQ or the potential vorticity anomaly in the 330 K isentropic surface (PV have been calculated with the aim of establishing different atmospheric stability scenarios. Furthermore, thermodynamic atmospheric stability contribution has been also evaluated with Total Totals index (TT and moisture availability was inferred from circulation weather types (CWTs. The first results of this work assess the combined dynamic-thermodynamic preferred conditions, synoptic situations and humidity sources, leading to precipitation events over the western Iberian Peninsula and prove the essential role of CWT patterns on the rainfall genesis.

  1. Energetic electron precipitation into the middle atmosphere - Constructing the loss cone fluxes from MEPED POES

    CERN Document Server

    Tyssøy, H Nesse; Ødegaard, L -K G; Stadsnes, J; Aasnes, A; Zawedde, A E

    2016-01-01

    The impact of energetic electron precipitation (EEP) on the chemistry of the middle atmosphere (50-90 km) is still an outstanding question as accurate quantification of EEP is lacking due to instrumental challenges and insufficient pitch angle coverage of current particle detectors. The Medium Energy Proton and Electron Detectors (MEPED) instrument on board the NOAA/Polar Orbiting Environmental Satellites(POES) and MetOp spacecraft has two sets of electron and proton telescopes pointing close to zenith ($0\\,^{\\circ}$) and in the horizontal plane ($90\\,^{\\circ}$). Using measurements from either the $0\\,^{\\circ}$ or $90\\,^{\\circ}$ telescope will underestimate or overestimate the bounce loss cone flux, respectively, as the energetic electron fluxes are often strongly anisotropic with decreasing fluxes toward the center of the loss cone. By combining the measurements from both telescopes with electron pitch angle distributions from theory of wave-particle interactions in the magnetosphere, a complete bounce loss ...

  2. Soil frost-induced soil moisture precipitation feedback and effects on atmospheric states

    Science.gov (United States)

    Hagemann, Stefan; Blome, Tanja; Ekici, Altug; Beer, Christian

    2016-04-01

    land atmosphere feedback to precipitation over the high latitudes, which reduces the model's wet biases in precipitation and evapotranspiration during the summer. This is noteworthy as soil moisture - atmosphere feedbacks have previously not been in the research focus over the high latitudes. These results point out the importance of high latitude physical processes at the land surface for the regional climate.

  3. The continuous detection of gamma (X-ray) spectra registered during atmospheric precipitations

    International Nuclear Information System (INIS)

    Monitoring of a gamma radiation in a ground atmosphere layer has revealed systematic increases during precipitations (rains, snowfalls). We have designed the instrument for the continuous detecting of differential spectra of a gamma radiation on the basis of spectrometers with sizes of scintillation crystals (Ø62×20 mm) and (Ø150× 100 mm). Registration of spectra of a gamma radiation is made with high resolution by means of the 4096-channel pulse-height analyzer over the energy range from 200 keV up to 4 MeV. Responses of crystals (effectiveness of detecting) to entering radiation have been calculated with the help of GEANT4 package. Instruments posed on the continuous registration of differential spectra of a gamma-ray background. In the present paper the preliminary results of observations carried out by the new instrument are presented. Measuring of spectra during increases of the gamma (X-rays) happening during precipitations, has shown absence in the spectra the characteristic lines of any radio nuclides in all the effective range. Spectra of a X-ray radiation over the range 20-400 keV, obtained earlier on the basis of crystal Ø63×20 mm, are well compounded with the data obtained with the crystal Ø150×100 mm and simulations by GEANT4 package. Joining of two detectors gives a possibility to study spectra of a gamma (X – ray) background and their variations from 20 keV up to 4 MeV.

  4. Seasonal Variations of Heavy Metals in Atmospheric Precipitation in the Area of Sarajevo Canton

    Directory of Open Access Journals (Sweden)

    Šehbajraktarević, K.

    2012-01-01

    Full Text Available Trace metals are natural components of the environment but they have become a matter of great concern because of the continuous increase in the concentrations of these metals in our environment. Atmospheric deposition is considered a major source of toxic metals such as Hg, Cd, Pb and several others in the ecosystem. The increasing use of rainwater as an alternative household water source has led to the increased interest in the monitoring of rainwater quality. The heavy metal (Cu, Cr, Cd, Mn, Ni and Hg in samples of atmospheric precipitation was determined in order to assess possible contamination of rainwater. The samples were collected continuously during three seasons (winter, spring and summer in the period from December 2009 to June 2010. The sampling was conducted at two sites of the Sarajevo Canton: Bjelave (urban area and Ivan Sedlo (rural area. The results showed that heavy metal contents (except copper and cadmium were higher in samples from Bjelave. The results showed levels of metals in all samples as: 0.52 – 19.08 μg L-1 (Cu, 0.007 – 2.55 μg L,-1 (Ni, 0.006 – 0.26 μg L-1 (Cr, 0.02 – 3.86 μg L-1 (Cd, 0.13 – 21.59 μg L-1 (Mn and 0.02 – 4.02 μg L-1 (Hg. The mean metal concentrations were below WHO’s limits for good quality drinking water. For most investigated metals, the highest content was obtained in precipitation sampled during spring/summer.

  5. Acceptable yearly precipitation and concentration of radioactive substances in atmospheric air

    International Nuclear Information System (INIS)

    The acceptable concentration of radionuclides in atmospheric air for the general population, taking into account only internal irradiation via inhalation, is presented in the radiation safety standards NRC-76/87. For most radionuclides this path is not critical. For this reason different derivative standards, which adequately account for other possible irradiation paths and can be measured, must be developed. In so doing, the following two circumstances must be taken into consideration: the expected irradiation dose is not related uniquely to the volume activity of radionuclides in air because during transport of a cloud of emissions in the atmosphere the aerosol particle-size spectrum becomes deformed and the average rate of precipitation of the aerosol changes (large particles settle near the emission location and the finely dispersed aerosol can be transported over a large distance); the foods consumed and all types of agroclimatic conditions under which agricultural crops are grown and the regional phenological characteristics of the crops are extremely diverse. The authors consider some features of the irradiation dose to the population from gas-aerosol emissions of radioactive substances. The irradiation dose to local residents from radioactive gas-aerosol emissions can be represented as the sum of contributions from different sources. The main sources are: external irradiation by the gas-aerosol emission cloud (primarily radioactive inert gases); internal irradiation from inhaled radionuclides; external irradiation from the track of radionuclides precipitated from the emission cloud onto the soils, and internal irradiation due to the consumption of local food products contaminated by the fallout

  6. An Overview of Energetic Particle Precipitation Effects on the Earth's Atmosphere and (Potentially) Climate

    Science.gov (United States)

    Jackman, Charles H.

    2012-01-01

    Energetic precipitating particles (EPPs) can cause significant constituent changes in the polar mesosphere and stratosphere (middle atmosphere) during certain periods. Both protons and electrons can influence the polar middle atmosphere through ionization and dissociation processes. EPPs can enhance HOx (H, OH, HO2) through the formation of positive ions followed by complex ion chemistry and NOx (N, NO, NO2) through the dissociation of molecular nitrogen. The solar EPP-created HOx increases can lead to ozone destruction in the mesosphere and upper stratosphere via several catalytic loss cycles. Such middle atmospheric HOx-caused ozone loss is rather short-lived due to the relatively short lifetime (hours) of the HOx constituents. The HOx-caused ozone depletion of greater than 30% has been observed during several large solar proton events (SPEs) in the past 50 years. HOx enhancements due to SPEs were confirmed by observations in solar cycle 23. A number of modeling studies have been undertaken over this time period that show predictions of enhanced HOx accompanied by decreased ozone due to energetic particles. The solar EPP-created NOx family has a longer lifetime than the HOx family and can also lead to catalytic ozone destruction. EPP-caused enhancements of the NOx family can affect ozone promptly, if produced in the stratosphere, or subsequently, if produced in the lower thermosphere or mesosphere and transported to the stratosphere. NOx enhancements due to auroral electrons, medium and high energy electrons, relativistic electron precipitation (REP) events, and SPEs have been measured and/or modeled for decades. Model predictions and measurements show that certain years have significant winter-time meteorological events, which result in the transport of EPP-caused NOx enhancements in the upper mesosphere and lower thermosphere to lower altitudes. The NOx-caused ozone depletion has also been observed during several solar proton events (SPEs) in the past 50 years

  7. THE SEASONAL DISTRIBUTION OF ATMOSPHERIC PRECIPITATIONS IN THE KHABAROVSK TERRITORY IN CONNECTION WITH FOREST FIRES

    OpenAIRE

    TELITSYN G.P.

    2009-01-01

    Our analysis of the relationship between sums of summer precipitations and sums of winter precipitations based on the data of three weather stations in the Khabarovsk territory for the years of 1974-2008 demonstrated that in 80 % of cases low sums (lower than the yearly average) of winter precipitations were followed by low sums of precipitations of the posterior summer, and vice versa.

  8. Interannual Variability of Autumn Precipitation over South China and its Relation to Atmospheric Circulation and SST Anomalies

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The interannual variability of autumn precipitation over South China and its relationship with atmospheric circulation and SST anomalies are examined using the autumn precipitation data of 160 stations in China and the NCEP-NCAR reanalysis dataset from 1951 to 2004. Results indicate a strong interannual variability of autumn precipitation over South China and its positive correlation with the autumn western Pacific subtropical high (WPSH). In the flood years, the WPSH ridge line lies over the south of South China and the strengthened ridge over North Asia triggers cold air to move southward. Furthermore, there exists a significantly anomalous updraft and cyclone with the northward stream strengthened at 850 hPa and a positive anomaly center of meridional moisture transport strengthening the northward warm and humid water transport over South China. These display the reverse feature in drought years. The autumn precipitation interannual variability over South China correlates positively with SST in the western Pacific and North Pacific, whereas a negative correlation occurs in the South Indian Ocean in July. The time of the strongest lag-correlation coefficients between SST and autumn precipitation over South China is about two months, implying that the SST of the three ocean areas in July might be one of the predictors for autumn precipitation interannual variability over South China. Discussion about the linkage among July SSTs in the western Pacific, the autumn WPSH and autumn precipitation over South China suggests that SST anomalies might contribute to autumn precipitation through its close relation to the autumn WPSH.

  9. Evaluation of candidate rain gages for upgrading precipitation measurement tools for the National Atmospheric Deposition Program

    Science.gov (United States)

    Gordon, John D.

    2003-01-01

    The National Atmospheric Deposition Program (NADP) was established in 1977 to investigate atmospheric deposition and its effects on the environment. Since its establishment, precipitation records have been obtained at all NADP sites using a gage developed approximately 50 years ago-the Belfort 5-780 mechanical rain gage. In 1998 and 1999, a study was done by the U.S. Geological Survey to evaluate four recently developed, technologically advanced rain gages as possible replacement candidates for the mechanical gage currently (2002) in use by the NADP. The gage types evaluated were the Belfort 3200, Geonor T-200, ETI Noah II, and the OTT PLUVIO. The Belfort 5-780 was included in the study to compare the performance of the rain gage currently (2002) used by NADP to the performance of the more recently developed gages. As a reference gage, the NovaLynx Model 260-2510 National Weather Service type stick gage also was included in the study. Two individual gages of each type were included in the study to evaluate precision between gages of the same type. A two-phase evaluation was completed. Phase I consisted of indoor bench tests with known amounts of simulated rainfall applied in 20 individual tests. Phase II consisted of outdoor testing by collecting precipitation during a 26-week period near Bay St. Louis, Mississippi. The ETI Noah II, OTT PLUVIO, and NovaLynx stick gages consistently recorded depths more commensurate with the amounts of applied simulated rainfall in Phase I testing than the Geonor T-200, Belfort 5-780, and Belfort 3200 gages. Gages where both the median difference between the measured and applied simulated rainfall and the interquartile range of all of their measured minus applied simulated rainfall differences were small (less than or equal to 0.01 inch) were judged to have performed very well in Phase I testing. The median and interquartile-range values were 0.01 inch or less for each of the ETI Noah II gages, OTT PLUVIO gages, and NovaLynx stick

  10. Impact of Atmospheric Infrared Sounder (AIRS) Thermodynamic Profiles on Regional Precipitation Forecasting

    Science.gov (United States)

    Chou, S.-H.; Zavodsky, B. T.; Jedloved, G. J.

    2010-01-01

    In data sparse regions, remotely-sensed observations can be used to improve analyses and lead to better forecasts. One such source comes from the Atmospheric Infrared Sounder (AIRS), which together with the Advanced Microwave Sounding Unit (AMSU), provides temperature and moisture profiles in clear and cloudy regions with accuracy which approaches that of radiosondes. The purpose of this paper is to describe an approach to assimilate AIRS thermodynamic profile data into a regional configuration of the Advanced Research WRF (ARW) model using WRF-Var. Quality indicators are used to select only the highest quality temperature and moisture profiles for assimilation in clear and partly cloudy regions, and uncontaminated portions of retrievals above clouds in overcast regions. Separate error characteristics for land and water profiles are also used in the assimilation process. Assimilation results indicate that AIRS profiles produce an analysis closer to in situ observations than the background field. Forecasts from a 37-day case study period in the winter of 2007 show that AIRS profile data can lead to improvements in 6-h cumulative precipitation forecasts resulting from improved thermodynamic fields. Additionally, in a convective heavy rainfall event from February 2007, assimilation of AIRS profiles produces a more unstable boundary layer resulting in enhanced updrafts in the model. These updrafts produce a squall line and precipitation totals that more closely reflect ground-based observations than a no AIRS control forecast. The location of available high-quality AIRS profiles ahead of approaching storm systems is found to be of paramount importance to the amount of impact the observations will have on the resulting forecasts.

  11. Electrostatic precipitation of dust in the Martian atmosphere: Implications for the utilization of resources during future manned exploration missions

    International Nuclear Information System (INIS)

    Future human missions to Mars will require the utilization of local resources for oxygen, fuel, and water. The In Situ Resource Utilization (ISRU) project is an active research endeavor at NASA to develop technologies that can enable cost effective ways to live off the land. The extraction of oxygen from the Martian atmosphere, composed primarily of carbon dioxide, is one of the most important goals of the Mars ISRU project. The main obstacle is the relatively large amount of dust present in the Martian atmosphere. This dust must be efficiently removed from atmospheric gas intakes for ISRU processing chambers. A common technique to achieve this removal on earth is by electrostatic precipitation, where large electrostatic fields are established in a localized region to charge, precipitate and collect dust particles. This technique is difficult to adapt to the Martian environment, with an atmospheric pressure of about one-hundredth of the terrestrial atmosphere. At these low pressures, the corona discharges required to implant an electrostatic charge to the particles to be collected is extremely difficult to sustain and the corona easily transitions to a glow/streamer discharge, which is unsuitable for particle charging. In this paper, we report on our successful efforts to establish a stable corona under Martian simulated conditions. We also present results on dust collecting efficiencies with an electrostatic precipitator prototype that could be effectively used on a future mission to the red planet.

  12. Electrostatic Precipitation of Dust in the Martian Atmosphere: Implications for the Utilization of Resources During Future Manned Exploration Missions

    Science.gov (United States)

    Calle, Carlos I.; Clements, Judson S.; Thompson, Samuel M.; Cox, Nathan D.; Hogue, Michael D.; Johansen, Michael R.; Williams, Blakeley S.

    2011-01-01

    Future human missions to Mars will require the utilization of local resources for oxygen, fuel. and water. The In Situ Resource Utilization (ISRU) project is an active research endeavor at NASA to develop technologies that can enable cost effective ways to live off the land. The extraction of oxygen from the Martian atmosphere. composed primarily of carbon dioxide, is one of the most important goals of the Mars ISRU project. The main obstacle is the relatively large amount of dust present in the Martian atmosphere. This dust must be efficiently removed from atmospheric gas intakes for ISRU processing chambers. A common technique to achieve this removal on earth is by electrostatic precipitation, where large electrostatic fields are established in a localized region to precipitate and collect previously charged dust particles. This technique is difficult to adapt to the Martian environment, with an atmospheric pressure of about one-hundredth of the terrestrial atmosphere. At these low pressures. the corona discharges required to implant an electrostatic charge to the particles to be collected is extremely difficult to sustain and the corona easily becomes biopolar. which is unsuitable for particle charging. In this paper, we report on our successful efforts to establish a stable corona under Martian simulated conditions. We also present results on dust collecting efficiencies with an electrostatic precipitator prototype that could be effectively used on a future mission to the red planet

  13. A CloudSat Perspective of the Atmospheric Water Cycle and Precipitation: Recent Progress and Grand Challenges

    Science.gov (United States)

    Stephens, Graeme L.; Im, Eastwood; Vane, Deborah

    2012-01-01

    Summary Global - mean precipitation - is controlled by Earth's energy balance and is a quantifiable consequence of the water vapor feedback. Predictability rests on the degree to which the water vapor feedback is predictable. Regional scale - to a significant extent, changes are shaped by atmospheric circulation changes but we do not know the extent to which regional scale changes are predictable. The impacts of changes to atmospheric circulation on regional scale water cycle changes can be dramatic. Process - scale - significant biases to the CHARACTER of precipitation (frequency and intensity) is related to how the precipitation process is parameterized in models. Aerosol - We still do not know the extent to which the water cycle is influenced by aerosol but anecdotal evidence is building. The character of precipitation is affected by the way aerosol influence clouds and thus affects the forcing of the climate system through the albedo effect. Observations - we still have a way to go and need to approach the problem in a more integrated way (tie clouds, aerosol and precipitation together and then link to soil moisture, etc). Globally our capabilities seriously lag behind the science and model development.

  14. Spatial analysis of extreme precipitation deficit as an index for atmospheric drought in Belgium

    Science.gov (United States)

    Zamani, Sepideh; Van De Vyver, Hans; Gobin, Anne

    2014-05-01

    The growing concern among the climate scientists is that the frequency of weather extremes will increase as a result of climate change. European society, for example, is particularly vulnerable to changes in the frequency and intensity of extreme events such as heat waves, heavy precipitation, droughts, and wind storms, as seen in recent years [1,2]. A more than 50% of the land is occupied by managed ecosystem (agriculture, forestry) in Belgium. Moreover, among the many extreme weather conditions, drought counts to have a substantial impact on the agriculture and ecosystem of the affected region, because its most immediate consequence is a fall in crop production. Besides the technological advances, a reliable estimation of weather conditions plays a crucial role in improving the agricultural productivity. The above mentioned reasons provide a strong motivation for a research on the drought and its impacts on the economical and agricultural aspects in Belgium. The main purpose of the presented work is to map atmospheric drought Return-Levels (RL), as first insight for agricultural drought, employing spatial modelling approaches. The likelihood of future drought is studied on the basis of precipitation deficit indices for four vegetation types: water (W), grass (G), deciduous (D) and coniferous forests (C) is considered. Extreme Value Theory (EVT) [3,4,5] as a branch of probability and statistics, is dedicated to characterize the behaviour of extreme observations. The tail behaviour of the EVT distributions provide important features about return levels. EVT distributions are applicable in many study areas such as: hydrology, environmental research and meteorology, insurance and finance. Spatial Generalized Extreme Value (GEV) distributions, as a branch of EVT, are applied to annual maxima of drought at 13 hydro-meteorological stations across Belgium. Superiority of the spatial GEV model is that a region can be modelled merging the individual time series of

  15. Carbonate precipitation in artificial soils as a sink for atmospheric carbon dioxide

    International Nuclear Information System (INIS)

    Turnover of C in soils is the dominant flux in the global C cycle and is responsible for transporting 20 times the quantity of anthropogenic emissions each year. This paper investigates the potential for soils to be modified with Ca-rich materials (e.g. demolition waste or basic slag) to capture some of the transferred C as geologically stable CaCO3. To test this principal, artificial soil known to contain Ca-rich minerals (Ca silicates and portlandite) was analysed from two sites across NE England, UK. The results demonstrate an average C content of 30 ± 15.3 Kg C m-2 stored as CaCO3, which is three times the expected organic C content and that it has accumulated at a rate of 25 ± 12.8 t C ha-1 a-1 since 1996. Isotopic analysis of the carbonates gave values between -6.4 per mille and -27.5 per mille for δ13C and -3.92 per mille and -20.89 per mille for δ18O, respectively (against V-PDB), which suggests that a combination of carbonate formation mechanisms are operating including the hydroxylation of gaseous CO2 in solution, and the sequestration of degraded organic C with minor remobilisation/precipitation of lithogenic carbonates. This study implies that construction/development sites may be designed with a C capture function to sequester atmospheric C into the soil matrix with a maximum global potential of 290 Mt C a-1.

  16. Determining precipitable water in the atmosphere of Iran based on GPS zenith tropospheric delays

    Directory of Open Access Journals (Sweden)

    Elaheh Sadeghi

    2014-08-01

    Full Text Available Precipitable water (PW is considered as one of the most important weather parameters in meteorology. Moreover, moisture affects the propagation of the Global Positioning System’s (GPS signals. Using four different models, the current paper tries to identify the best relationship between the atmospheric error known as zenith wet delay (ZWD and PW. For that matter, based on 54,330 radiosonde profiles from 11 stations, two different models i.e. linear and quadratic have been derived for Iran. For analyzing the accuracy of these models, ZWDs of three permanent GPS stations located in the cities of Tehran, Ahvaz and Tabriz have been used. Applying the aforementioned models as well as those already developed for Europe and the U.S., PWs are derived at the position of these stations in Iran. Further, in this research, root mean square error (RMSE and bias are the measures for selecting the optimal model. Here, the bias and the RMSE (between GPS and radiosonde derived PWs for the proposed linear model for Iran is 1.44 mm and 4.42 mm, and for quadratic model 2.18 mm and 4.74 mm respectively while, the bias and the RMSE for Bevis’ linear model is 2.63 mm and 4.98 mm and for Emardson and Derk’s quadratic models are 2.80 mm and 5.08 mm respectively. As such, it is observed that the bias of the proposed linear model for Iran is 1.19 mm and 1.36 mm less than the Bevis’ and Emardson and Derk’s models. In addition, the RMSE of the proposed linear model is 0.56 and 0.66 mm less than the RMSE of the later ones. This emphasizes that the estimation of the model coefficients must be based on regional meteorological measurements.

  17. Influence of Large-scale Climate Modes on Atmospheric Rivers That Drive Regional Precipitation Extremes

    Science.gov (United States)

    Guan, B.; Molotch, N. P.; Waliser, D. E.; Fetzer, E. J.; Neiman, P. J.

    2014-12-01

    Atmospheric rivers (ARs) are narrow channels of enhanced meridional water vapor transport between the tropics and extratropics that drive precipitation extremes in the west coast areas of North America and other continents. The influence of large-scale climate modes on ARs is analyzed in terms of modulation on AR frequency and AR-related snow water equivalent (SWE) anomalies, with a focus on understanding the causes of the anomalously snowy winter season of 2010/2011 in California's Sierra Nevada. Mean SWE on 1 April 2011 was ~70% above normal averaged over 100 snow sensors. AR occurrence was anomalously high during the season, with 20 AR dates from November to March and 14 dates in the month of December 2010, compared to the mean occurrence of 9 dates per season. Most of the season's ARs occurred during negative phases of the Arctic Oscillation (AO) and the Pacific-North American (PNA) teleconnection pattern. Analysis of all winter ARs in California during water years 1998-2011 indicates more ARs occur during the negative phase of AO and PNA, with the increase between positive and negative phases being ~90% for AO, and ~50% for PNA. The circulation pattern associated with concurrent negative phases of AO and PNA, characterized by cyclonic anomalies centered northwest of California, provides a favorable dynamical condition for ARs. The analysis suggests that the massive Sierra Nevada snowpack during the 2010/2011 winter season is primarily related to anomalously high frequency of ARs favored by the joint phasing of -AO and -PNA, and that a secondary contribution is from increased snow accumulation during these ARs favored by colder air temperatures associated with -AO, -PNA and La Niña. The results have implications for subseasonal-to-seasonal predictability of AR activities and related weather and water extremes.

  18. Comparison of precipitation chemistry measurements obtained by the Canadian Air and Precipitation Monitoring Network and National Atmospheric Deposition Program for the period 1995-2004

    Science.gov (United States)

    Wetherbee, Gregory A.; Shaw, Michael J.; Latysh, Natalie E.; Lehmann, Christopher M.B.; Rothert, Jane E.

    2010-01-01

    Precipitation chemistry and depth measurements obtained by the Canadian Air and Precipitation Monitoring Network (CAPMoN) and the US National Atmospheric Deposition Program/National Trends Network (NADP/NTN) were compared for the 10-year period 1995–2004. Colocated sets of CAPMoN and NADP instrumentation, consisting of precipitation collectors and rain gages, were operated simultaneously per standard protocols for each network at Sutton, Ontario and Frelighsburg, Ontario, Canada and at State College, PA, USA. CAPMoN samples were collected daily, and NADP samples were collected weekly, and samples were analyzed exclusively by each network’s laboratory for pH, H + , Ca2+  , Mg2+  , Na + , K + , NH+4 , Cl − , NO−3 , and SO2−4 . Weekly and annual precipitation-weighted mean concentrations for each network were compared. This study is a follow-up to an earlier internetwork comparison for the period 1986–1993, published by Alain Sirois, Robert Vet, and Dennis Lamb in 2000. Median weekly internetwork differences for 1995–2004 data were the same to slightly lower than for data for the previous study period (1986–1993) for all analytes except NO−3 , SO2−4 , and sample depth. A 1994 NADP sampling protocol change and a 1998 change in the types of filters used to process NADP samples reversed the previously identified negative bias in NADP data for hydrogen-ion and sodium concentrations. Statistically significant biases (α = 0.10) for sodium and hydrogen-ion concentrations observed in the 1986–1993 data were not significant for 1995–2004. Weekly CAPMoN measurements generally are higher than weekly NADP measurements due to differences in sample filtration and field instrumentation, not sample evaporation, contamination, or analytical laboratory differences.

  19. Atmospheric conditions associated with heavy precipitation events in comparison to seasonal means in the western mediterranean region

    Science.gov (United States)

    Khodayar, Samiro; Kalthoff, Norbert; Kottmeier, Christoph

    2016-03-01

    The autumn atmospheric conditions associated with Heavy Precipitation Events (HPEs) in the western mediterranean region and differences with respect to the seasonal-mean conditions are investigated. Seasonal high-resolution simulations from the regional climate model COSMO-CLM covering the autumn periods of 2011 and 2012 are used. Atmospheric conditions at five different subdomains surrounding the western Mediterranean are considered, namely France, Italy (North and South), Spain, and North Africa. During HPEs, moisture and instability sources are located generally upstream of the target area over the sea, being transported by fast low-level winds towards the HPE areas. Concentration of high humidity over land and initiation of convection are highly related to the orography in the area. Stronger convective precipitation events occur at mid-level elevations rather than at higher altitudes. The significant increase in atmospheric moisture and instability, identified prior to HPEs, builds up in two different time lengths: atmospheric moisture increase could be traced back to at least 6-24 h before the initiation stage of the event, whereas an increase of Convective Available Potential Energy (CAPE) is detected in the hours prior to the event during the mature stage. The most intense HPEs are in general associated with higher values of integrated water vapour, CAPE, and low-level and mid-tropospheric wind speed. During HPEs in all subdomains, the dominant precipitation peak occurs between 1200 and 1800 UTC suggesting that convective precipitation prevails in most HPEs. The diurnal cycle of integrated water vapour during the mature stage of HPEs shows that the atmosphere remains wetter than average for most of the period and that only a decrease is seen after the afternoon precipitation peak. Negligible CAPE characterizes mean-seasonal conditions while the classical diurnal cycle with the peak in the early afternoon and much higher mean values occur during HPE events

  20. Influence of land-atmosphere feedbacks on temperature and precipitation extremes in the GLACE-CMIP5 ensemble

    Science.gov (United States)

    Lorenz, Ruth; Argüeso, Daniel; Donat, Markus G.; Pitman, Andrew J.; Hurk, Bart; Berg, Alexis; Lawrence, David M.; Chéruy, Frédérique; Ducharne, Agnès.; Hagemann, Stefan; Meier, Arndt; Milly, P. C. D.; Seneviratne, Sonia I.

    2016-01-01

    We examine how soil moisture variability and trends affect the simulation of temperature and precipitation extremes in six global climate models using the experimental protocol of the Global Land-Atmosphere Coupling Experiment of the Coupled Model Intercomparison Project, Phase 5 (GLACE-CMIP5). This protocol enables separate examinations of the influences of soil moisture variability and trends on the intensity, frequency, and duration of climate extremes by the end of the 21st century under a business-as-usual (Representative Concentration Pathway 8.5) emission scenario. Removing soil moisture variability significantly reduces temperature extremes over most continental surfaces, while wet precipitation extremes are enhanced in the tropics. Projected drying trends in soil moisture lead to increases in intensity, frequency, and duration of temperature extremes by the end of the 21st century. Wet precipitation extremes are decreased in the tropics with soil moisture trends in the simulations, while dry extremes are enhanced in some regions, in particular the Mediterranean and Australia. However, the ensemble results mask considerable differences in the soil moisture trends simulated by the six climate models. We find that the large differences between the models in soil moisture trends, which are related to an unknown combination of differences in atmospheric forcing (precipitation, net radiation), flux partitioning at the land surface, and how soil moisture is parameterized, imply considerable uncertainty in future changes in climate extremes.

  1. An analytical model for dispersion of material in the atmospheric planetary boundary layer in presence of precipitation

    International Nuclear Information System (INIS)

    An analytical model for the dispersion of particulates and finely divided material released into the atmosphere near the ground is presented. The possible precipitation when the particles are dense enough and large enough to have deposition velocity, is taken into consideration. The model is derived analytically in the mixing layer or Ekman boundary layer where the mixing process is a direct consequence of turbulent and convective motions generated in the boundary layer. (author)

  2. A PV-gradient related quantity in moist atmosphere and its application in the diagnosis of heavy precipitation

    Science.gov (United States)

    Li, Na; Gao, Shouting; Ran, Lingkun

    2016-01-01

    In this paper, a PV-gradient related parameter-the second-order potential vorticity (SPV) is generalized into a non-uniformly saturated atmosphere to involve the PV-gradient into precipitation diagnosis, assuming that PV gradient is more capable of describing the whole structure of the air mass boundaries than other single element gradients. The newly derived second-order moist potential vorticity (SMPV), which is defined as the dot product of the generalized vorticity vector and three-dimensional gradient of a conserved form of generalized potential vorticity (GPV), keeps the conserved property as SPV in the frictionless, moist adiabatic atmosphere. Nevertheless, due to the complex calculation of SMPV, a non-conservative form of SMPV (NSMPV) is subtracted from SMPV, which is defined as the dot product of vorticity vector and three-dimensional gradient of GPV by involving the baroclinic vorticity. The capability of the NSMPV on diagnosing and detecting heavy precipitation is examined for a heavy rainfall case, with GPV as a comparison. A typical scale analyses in this case shows that GPV is mainly a coupling of static stability and vertical vorticity, while NSMPV contains static stability, vorticity enstrophy and their vertically inhomogeneity. Due to these information, both GPV and NSMPV show strong anomalies over the precipitation region, by reflecting the cyclonic shear and large vertical variations of temperature and humidity in the lower troposphere. However, GPV also appears strong, wide anomalies out of the precipitation region while NSMPV does not. In addition, due to the vertical gradient of vorticity enstrophy and static stability contained in NSMPV, it also has a reflection on the invasion of cold, dry air in the near-surface layer, which is seen to be a triggering mechanism of the strong precipitation. This indicates that NSMPV perform better than GPV in detecting heavy rainfall and are powerful on distinguishing between precipitation and non-precipitation

  3. Inter-annual temperature and precipitation variations over the Litani Basin in response to atmospheric circulation patterns

    Science.gov (United States)

    Ramadan, H. H.; Ramamurthy, A. S.; Beighley, R. E.

    2012-05-01

    This study examines the sensitivity of a mid-size basin's temperature and precipitation response to different global and regional climate circulation patterns. The implication of the North Atlantic Oscillation (NAO), El Niño Southern Oscillation (ENSO), Indian Monsoon and ten other teleconnection patterns of the Northern Hemisphere are investigated. A methodology to generate a basin-scale, long-term monthly surface temperature and precipitation time series has been established using different statistical tests. The Litani River Basin is the focus of this study. It is located in Lebanon, east of the Mediterranean Basin, which is known to have diverse geophysical and environmental characteristics. It was selected to explore the influence of the diverse physical and topographical features on its hydroclimatological response to global and regional climate patterns. We also examine the opportunity of conducting related studies in areas with limited long-term measured climate and/or hydrological data. Litani's monthly precipitation and temperature data have been collected and statistically extrapolated using remotely sensed data products from satellites and as well as in situ gauges. Correlations between 13 different teleconnection indices and the basin's precipitation and temperature series are investigated. The study shows that some of the annual and seasonal temperature and precipitation variance can be partially associated with many atmospheric circulation patterns. This would give the opportunity to relate the natural climate variability with the watershed's hydroclimatology performance and thus differentiate it from other anthropogenic induced climate change outcomes.

  4. Precipitation efficiency derived from isotope ratios in water vapor distinguishes dynamical and microphysical influences on subtropical atmospheric constituents

    Science.gov (United States)

    Bailey, A.; Nusbaumer, J.; Noone, D.

    2015-09-01

    With water vapor and clouds expected to effect significant feedbacks on climate, moisture transport through convective processes has important implications for future temperature change. The precipitation efficiency—the ratio of the rates at which precipitation and condensation form (e = P/C)—is useful for characterizing how much boundary layer moisture recycles through precipitation versus mixes into the free troposphere through cloud detrainment. Yet it is a difficult metric to constrain with traditional observational techniques. This analysis characterizes the precipitation efficiency of convection near the Big Island of Hawaii, USA, using a novel tracer: isotope ratios in water vapor. The synoptic circulation patterns associated with high and low precipitation efficiency are identified, and the importance of large-scale dynamics and local convective processes in regulating vertical distributions of atmospheric constituents important for climate is evaluated. The results suggest that high e days are correlated with plume-like transport originating from the relatively clean tropics, while low e days are associated with westerly transport, generated by a branching of the jet stream. Differences in transport pathway clearly modify background concentrations of water vapor and other trace gases measured at Mauna Loa Observatory; however, local convective processes appear to regulate aerosols there. Indeed, differences between observed and simulated diurnal cycles of particle number concentration indicate that precipitation scavenges aerosols and possibly facilitates new particle formation when e is high. As measurements of isotope ratios in water vapor expand across the subtropics, the techniques presented here can further our understanding of how synoptic weather, precipitation processes, and climate feedbacks interrelate.

  5. The use of high-resolution atmospheric simulations over mountainous terrain for deriving error correction functions of satellite precipitation products

    Science.gov (United States)

    Bartsotas, Nikolaos S.; Nikolopoulos, Efthymios I.; Anagnostou, Emmanouil N.; Kallos, George

    2015-04-01

    Mountainous regions account for a significant part of the Earth's surface. Such areas are persistently affected by heavy precipitation episodes, which induce flash floods and landslides. The limitation of inadequate in-situ observations has put remote sensing rainfall estimates on a pedestal concerning the analyses of these events, as in many mountainous regions worldwide they serve as the only available data source. However, well-known issues of remote sensing techniques over mountainous areas, such as the strong underestimation of precipitation associated with low-level orographic enhancement, limit the way these estimates can accommodate operational needs. Even locations that fall within the range of weather radars suffer from strong biases in precipitation estimates due to terrain blockage and vertical rainfall profile issues. A novel approach towards the reduction of error in quantitative precipitation estimates lies upon the utilization of high-resolution numerical simulations in order to derive error correction functions for corresponding satellite precipitation data. The correction functions examined consist of 1) mean field bias adjustment and 2) pdf matching, two procedures that are simple and have been widely used in gauge-based adjustment techniques. For the needs of this study, more than 15 selected storms over the mountainous Upper Adige region of Northern Italy were simulated at 1-km resolution from a state-of-the-art atmospheric model (RAMS/ICLAMS), benefiting from the explicit cloud microphysical scheme, prognostic treatment of natural pollutants such as dust and sea-salt and the detailed SRTM90 topography that are implemented in the model. The proposed error correction approach is applied on three quasi-global and widely used satellite precipitation datasets (CMORPH, TRMM 3B42 V7 and PERSIANN) and the evaluation of the error model is based on independent in situ precipitation measurements from a dense rain gauge network (1 gauge / 70 km2

  6. Atmospheric residence times from transpiration and evaporation to precipitation: An age-weighted regional evaporation tagging approach

    Science.gov (United States)

    Wei, Jianhui; Knoche, Hans Richard; Kunstmann, Harald

    2016-06-01

    The atmospheric water residence time is a fundamental descriptor that provides information on the timescales of evaporation and precipitation. In this study, a regional climate model-based evaporation tagging algorithm is extended with an age tracer approach to calculate moisture residence times, defined as time between the original evaporation and the returning of water masses to the land surface as precipitation. Our case study addresses how long this time is for the transpired and for the direct evaporated moisture. Our study region is the Poyang Lake region in Southeast China, the largest freshwater lake in the country. We perform simulations covering the period from October 2004 to December 2005. In 2005, 11% of direct evaporated water (10% of transpired water) precipitates locally. Direct evaporated water accounts for 64% and transpired water for 36% of the total tagged moisture with a mean age of around 36 h for both. Considering precipitation, a large proportion (69%) originates from direct evaporated water with a mean atmospheric residence time of 6.6 h and a smaller amount from transpired water with a longer residence time of 10.7 h. Modulated by the East Asian monsoon, the variation of the meteorological conditions, the magnitude of the partitioned moisture, and the corresponding residence time patterns change seasonally and spatially and reveal the different fate of transpired and direct evaporated water in the atmospheric hydrological cycle. We conclude that our methodological approach has the potential to be used for addressing how timescales of the hydrological cycle changes regionally under global warming.

  7. Land-total and Ocean-total Precipitation and Evaporation from a Community Atmosphere Model version 5 Perturbed Parameter Ensemble

    Energy Technology Data Exchange (ETDEWEB)

    Covey, Curt [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lucas, Donald D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Trenberth, Kevin E. [National Center for Atmospheric Research, Boulder, CO (United States)

    2016-03-02

    This document presents the large scale water budget statistics of a perturbed input-parameter ensemble of atmospheric model runs. The model is Version 5.1.02 of the Community Atmosphere Model (CAM). These runs are the “C-Ensemble” described by Qian et al., “Parametric Sensitivity Analysis of Precipitation at Global and Local Scales in the Community Atmosphere Model CAM5” (Journal of Advances in Modeling the Earth System, 2015). As noted by Qian et al., the simulations are “AMIP type” with temperature and sea ice boundary conditions chosen to match surface observations for the five year period 2000-2004. There are 1100 ensemble members in addition to one run with default inputparameter values.

  8. Quantitative balance and interception of atmospheric precipitation in the climax oak ecosystem

    International Nuclear Information System (INIS)

    This paper deals with the results of research of precipitation balance in oak ecosystem. Research is carried out in the National Nature Reserve Boky in Kremnica hills. It deals with the influence of the forest on rainfall volume under the top of oak, which we compare with the free country or under-top area of beech. In this study, we also compared the foliage aspects in connection with interception and relation of partial precipitation capture in tree-tops. (author)

  9. Effects of precipitation on sonic anemometer measurements of turbulent fluxes in the atmospheric surface layer

    Science.gov (United States)

    Zhang, Rongwang; Huang, Jian; Wang, Xin; Zhang, Jun A.; Huang, Fei

    2016-06-01

    Effects caused by precipitation on the measurements of three-dimensional sonic anemometer are analyzed based on a field observational experiment conducted in Maoming, Guangdong Province, China. Obvious fluctuations induced by precipitation are observed for the outputs of sonic anemometer-derived temperature and wind velocity components. A technique of turbulence spectra and cospectra normalized in the framework of similarity theory is utilized to validate the measured variables and calculated fluxes. It is found that the sensitivity of sonic anemometer-derived temperature to precipitation is significant, compared with that of the wind velocity components. The spectra of wind velocity and cospectra of momentum flux resemble the standard universal shape with the slopes of the spectra and cospectra at the inertial subrange, following the -2/3 and -4/3 power law, respectively, even under the condition of heavy rain. Contaminated by precipitation, however, the spectra of temperature and cospectra of sensible heat flux do not exhibit a universal shape and have obvious frequency loss at the inertial subrange. From the physical structure and working principle of sonic anemometer, a possible explanation is proposed to describe this difference, which is found to be related to the variations of precipitation particles. Corrections for errors of sonic anemometer-derived temperature under precipitation is needed, which is still under exploration.

  10. Development of an Electrostatic Precipitator to Remove Martian Atmospheric Dust from ISRU Gas Intakes During Planetary Exploration Missions

    Science.gov (United States)

    Clements, J. Sidney; Thompson, Samuel M.; Cox, Nathan D.; Johansen, Michael R.; Williams, Blakeley S.; Hogue, Michael D.; Lowder, M. Loraine; Calle, Carlos I.

    2011-01-01

    Manned exploration missions to Mars will need dependable in situ resource utilization (ISRU) for the production of oxygen and other commodities. One of these resources is the Martian atmosphere itself, which is composed of carbon dioxide (95.3%), nitrogen (2.7%), argon (1.6%), oxygen (0.13%), carbon monoxide (0.07%), and water vapor (0.03%), as well as other trace gases. However, the Martian atmosphere also contains relatively large amounts of dust, uploaded by frequent dust devils and high Winds. To make this gas usable for oxygen extraction in specialized chambers requires the removal of most of the dust. An electrostatic precipitator (ESP) system is an obvious choice. But with an atmospheric pressure just one-hundredth of Earth's, electrical breakdown at low voltages makes the implementation of the electrostatic precipitator technology very challenging. Ion mobility, drag forces, dust particle charging, and migration velocity are also affected because the low gas pressure results in molecular mean free paths that are approximately one hundred times longer than those at Earth .atmospheric pressure. We report here on our efforts to develop this technology at the Kennedy Space Center, using gases with approximately the same composition as the Martian atmosphere in a vacuum chamber at 9 mbars, the atmospheric pressure on Mars. We also present I-V curves and large particle charging data for various versions of wire-cylinder and rod-cylinder geometry ESPs. Preliminary results suggest that use of an ESP for dust collection on Mars may be feasible, but further testing with Martian dust simulant is required.

  11. Observational constraints on atmospheric and oceanic cross-equatorial heat transports: revisiting the precipitation asymmetry problem in climate models

    Science.gov (United States)

    Loeb, Norman G.; Wang, Hailan; Cheng, Anning; Kato, Seiji; Fasullo, John T.; Xu, Kuan-Man; Allan, Richard P.

    2016-05-01

    Satellite based top-of-atmosphere (TOA) and surface radiation budget observations are combined with mass corrected vertically integrated atmospheric energy divergence and tendency from reanalysis to infer the regional distribution of the TOA, atmospheric and surface energy budget terms over the globe. Hemispheric contrasts in the energy budget terms are used to determine the radiative and combined sensible and latent heat contributions to the cross-equatorial heat transports in the atmosphere (AHTEQ) and ocean (OHTEQ). The contrast in net atmospheric radiation implies an AHTEQ from the northern hemisphere (NH) to the southern hemisphere (SH) (0.75 PW), while the hemispheric difference in sensible and latent heat implies an AHTEQ in the opposite direction (0.51 PW), resulting in a net NH to SH AHTEQ (0.24 PW). At the surface, the hemispheric contrast in the radiative component (0.95 PW) dominates, implying a 0.44 PW SH to NH OHTEQ. Coupled model intercomparison project phase 5 (CMIP5) models with excessive net downward surface radiation and surface-to-atmosphere sensible and latent heat transport in the SH relative to the NH exhibit anomalous northward AHTEQ and overestimate SH tropical precipitation. The hemispheric bias in net surface radiative flux is due to too much longwave surface radiative cooling in the NH tropics in both clear and all-sky conditions and excessive shortwave surface radiation in the SH subtropics and extratropics due to an underestimation in reflection by clouds.

  12. A one-way coupled atmospheric-hydrological modeling system with combination of high-resolution and ensemble precipitation forecasting

    Science.gov (United States)

    Wu, Zhiyong; Wu, Juan; Lu, Guihua

    2015-11-01

    Coupled hydrological and atmospheric modeling is an effective tool for providing advanced flood forecasting. However, the uncertainties in precipitation forecasts are still considerable. To address uncertainties, a one-way coupled atmospheric-hydrological modeling system, with a combination of high-resolution and ensemble precipitation forecasting, has been developed. It consists of three high-resolution single models and four sets of ensemble forecasts from the THORPEX Interactive Grande Global Ensemble database. The former provides higher forecasting accuracy, while the latter provides the range of forecasts. The combined precipitation forecasting was then implemented to drive the Chinese National Flood Forecasting System in the 2007 and 2008 Huai River flood hindcast analysis. The encouraging results demonstrated that the system can clearly give a set of forecasting hydrographs for a flood event and has a promising relative stability in discharge peaks and timing for warning purposes. It not only gives a deterministic prediction, but also generates probability forecasts. Even though the signal was not persistent until four days before the peak discharge was observed in the 2007 flood event, the visualization based on threshold exceedance provided clear and concise essential warning information at an early stage. Forecasters could better prepare for the possibility of a flood at an early stage, and then issue an actual warning if the signal strengthened. This process may provide decision support for civil protection authorities. In future studies, different weather forecasts will be assigned various weight coefficients to represent the covariance of predictors and the extremes of distributions.

  13. Diagnosing Atmospheric Influences on the Interannual 18O/16O Variations in Western U.S. Precipitation

    Directory of Open Access Journals (Sweden)

    Kei Yoshimura

    2013-07-01

    Full Text Available Many climate proxies in geological archives are dependent on the isotopic content of precipitation (δ18Op, which over sub-annual timescales has been linked to temperature, condensation height, atmospheric circulation, and post-condensation exchanges in the western U.S. However, many proxies do not resolve temporal changes finer than interannual-scales. This study explores causes of the interannual variations in δ18Op within the western U.S. Simulations with the Isotope-incorporated Global Spectral Model (IsoGSM revealed an amplifying influence of post-condensation exchanges (i.e., raindrop evaporation and vapor equilibration on interannual δ18Op variations throughout the western U.S. Mid-latitude and subtropical vapor tagging simulations showed that the influence of moisture advection on δ18Op was relatively strong in the Pacific Northwest, but weak over the rest of the western U.S. The vapor tags correlated well with interannual variations in the 18O/16O composition of vapor, an indication that isotopes in vapor trace atmospheric circulation. However, vertical-tagging simulations revealed a strong influence of condensation height on δ18Op in California. In the interior of the western U.S., a strong temperature effect was found only after annual mean temperatures were weighted by monthly precipitation totals. These multiple influences on δ18Op complicate interpretations of western U.S. climate proxies that are derived from isotopes in precipitation.

  14. The role of atmospheric precipitation in introducing contaminants to the surface waters of the Fuglebekken catchment, Spitsbergen

    Directory of Open Access Journals (Sweden)

    Katarzyna Kozak

    2015-11-01

    Full Text Available Although the Svalbard Archipelago is located at a high latitude, far from potential contaminant sources, it is not free from anthropogenic impact. Towards the Fuglebekken catchment, in the southern part of Spitsbergen, north of Hornsund fjord, contaminants can be transported from mainland pollution sources. In the precipitation and surface water collected in the catchment, the following elements were detected and quantified: Ag, Al, As, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Cs, Mo, Ni, Pb, Sb, Se, Sr, Tl, U, V and Zn. Additionally, pH, electrical conductivity and total organic carbon (TOC were determined in those samples. The acidic reaction of precipitation waters was identified as an important factor intensifying the metal migration in this Arctic tundra environment. The air mass trajectory, surprisingly, explained the variability of only a small fraction of trace elements in precipitation water. The air mass origin area was correlated only with the concentrations of As, V and Cr. Wind directions were helpful in explaining the variability of Mn, U and Ba concentrations (east–north-easterly wind and the contents of B, As, Rb, Se, Sr and Li in precipitation (south-westerly wind, which may indicate the local geological source of those. Atmospheric deposition was found to play a key role in the transport of contaminants into the Fuglebekken catchment; however, the surface water composition was modified by its pH and TOC content.

  15. Response in atmospheric circulation and sources of Greenland precipitation to glacial boundary conditions

    DEFF Research Database (Denmark)

    Langen, Peter Lang; Vinther, Bo Møllesøe

    cooler tropics and less sea ice. The occurrence of such a shift depends chiefly on the SST reconstruction and not on the existence of the large northern hemisphere glacial ice sheets. The influence of these circulation changes on important factors for ice core interpretation such as precipitation...

  16. Interdecadal Variations of Precipitation and Temperature in China Around the Abrupt Change of Atmospheric Circulation in 1976

    Institute of Scientific and Technical Information of China (English)

    LI Chunhui; WAN Qilin; LIN Ailan; GU Dejun; ZHENG Bin

    2009-01-01

    The interdecadal characteristics of rainfall and temperature in China before and after the abrupt change of the general circulation in 1976 are analyzed using the global 2.5°×2.5° monthly mean reanalysis data from the National Centers for Environmental Prediction of US and the precipitation and temperature data at the 743 stations of China from the National Climate Center of China. The results show that after 1976, springtime precipitation and temperature were anomalously enhanced and reduced respectively in South China, while the reverse was true in the western Yangtze River basin. In summer, precipitation was anomalously less in South China, more in the Yangtze River basin, less again in North China and more again in Northeast China, showing a distribution pattern alternating with negative and positive anomalies ("-, +, -, +"). Meanwhile, temperature shows a distribution of warming in South China, cooling in the Yangtze and Huaihe River basins, and warming again in northern China. In autumn, precipitation tended to decrease and temperature tended to increase in most parts of the country. In winter, precipitation increased moderately in South China and warming was the trend across all parts of China. The interdecadal decline of mean temperature in spring and summer in China was mainly due to the daily maximum temperature variation, while the interdecadal increase was mainly the result of the minimum temperature change. The overall warming in autumn (winter) was mostly influenced by the minimum (maximum) temperature variation. These changes were closely related to the north-south shifts of the ascending and descending branches of the Hadley cell, the strengthening and north-south progression of the westerly jet stream, and the atmospheric stratification and water vapor transport conditions.

  17. The key physical parameters governing frictional dissipation in a precipitating atmosphere

    CERN Document Server

    Makarieva, Anastassia M; Nefiodov, Andrei V; Sheil, Douglas; Nobre, Antonio; Bunyard, Peter; Li, Bai-Lian

    2012-01-01

    Precipitation generates small-scale turbulent air flows the energy of which ultimately dissipates to heat. The power of this process has previously been estimated to be around 2-4 W m-2 in the tropics: a value comparable in magnitude to the dynamic power of the global circulation. Here we suggest that this previous power estimate is approximately double the true figure. Our result reflects a revised evaluation of the mean precipitation path length Hp. We investigate the dependence of Hp on surface temperature,relative humidity,temperature lapse rate and degree of condensation in the ascending air. We find that the degree of condensation,defined as the relative change of the saturated water vapor mixing ratio in the region of condensation, is a major factor determining Hp. We estimate from theory that the mean large-scale rate of frictional dissipation associated with total precipitation in the tropics lies between 1 and 2 W m-2 and show that our estimate is supported by empirical evidence. We show that under ...

  18. Five-year record of atmospheric precipitation chemistry in urban Beijing, China

    Directory of Open Access Journals (Sweden)

    F. Yang

    2011-10-01

    Full Text Available Precipitation samples on an event basis were collected from March 2001 through August 2005 at an urban location in Beijing. Ionic species in the samples were measured with ion chromatography to understand the long-term changes in the precipitation chemistry and their causes. Most precipitation samples had an intermediate pH (6.1–7.3 and 16% were acidic. As the major ions, SO42− plus NO3, and NH4+ plus Ca2+ comprised more than 80% of anionic and cationic mass, respectively. Different from their more or less reductions of gaseous precursors, the counterintuitive features of much less than expected decrease in SO42− levels and unexpected increase in NO3 concentrations in the precipitations are likely due to the combination of enhanced conversion of gaseous precursors to acid compounds, and increased regional transport. The average ratio of neutralizing to acidifying potential (i.e. NP/AP was as high as 1.2 but it exhibited a significant decline pattern, indicative of a long-term increasing trend in the acidifying potential of the wet depositions. This is mainly ascribed to reduced input of two major alkaline agents – NH4+ and Ca2+ – over increased input of a minor alkaline agent – Mg2+ – according to the magnitudes of their neutralization factors. The equivalent mass ratio of NO3 to nss-SO42− presented an evident increasing trend with a still low mean value of 0.37 ± 0.11. This indicates that the relative contribution of NO3 to the wet deposition acidity was strengthened in recent years while the precipitation acidity in Beijing was still overwhelmingly from sulfur but not nitrogen.

  19. Data Assimilation of AIRS Water Vapor Profiles: Impact on Precipitation Forecasts for Atmospheric River Cases Affecting the Western of the United States

    Science.gov (United States)

    Blankenship, Clay; Zavodsky, Bradley; Jedlovec, Gary; Wick, Gary; Neiman, Paul

    2013-01-01

    Atmospheric rivers are transient, narrow regions in the atmosphere responsible for the transport of large amounts of water vapor. These phenomena can have a large impact on precipitation. In particular, they can be responsible for intense rain events on the western coast of North America during the winter season. This paper focuses on attempts to improve forecasts of heavy precipitation events in the Western US due to atmospheric rivers. Profiles of water vapor derived from from Atmospheric Infrared Sounder (AIRS) observations are combined with GFS forecasts by a three-dimensional variational data assimilation in the Gridpoint Statistical Interpolation (GSI). Weather Research and Forecasting (WRF) forecasts initialized from the combined field are compared to forecasts initialized from the GFS forecast only for 3 test cases in the winter of 2011. Results will be presented showing the impact of the AIRS profile data on water vapor and temperature fields, and on the resultant precipitation forecasts.

  20. Extreme precipitation and climate gradients in Patagonia revealed by high-resolution regional atmospheric climate modeling

    NARCIS (Netherlands)

    Lenaerts, J.T.M.; van den Broeke, M.R.; van Wessem, J.M.; van de Berg, W.J.; van Meijgaard, E.; van Ulft, L.H.; Schaefer, M.

    2014-01-01

    This study uses output of a high-resolution (5.5 km) regional atmospheric climate model to describe the present-day (1979–2012) climate of Patagonia, with a particular focus on the surface mass balance (SMB) of the Patagonian ice fields. Through a comparison with available in situ observations, it i

  1. Diagnosing the possible dynamics controlling Sahel precipitation in the short-range ensemble community atmospheric model hindcasts

    Science.gov (United States)

    Tseng, Yu-heng; Lin, Yen-heng; Lo, Min-hui; Yang, Shu-chih

    2016-01-01

    The actual dynamics and physical mechanisms affecting the Sahel precipitation pattern and amplitude in the climate models remain under debate due to the inconsistent drying and rainfall variability/pattern among them. We diagnose the boreal summer rainfall pattern in the Sahel and its possible causes using short-range ensemble hindcasts based on NCAR community atmospheric model with the local ensemble transform Kalman filter (CAM-LETKF) data assimilation. The CAM-LETKF assimilation was conducted using 64 ensemble members with an assimilation cycle of 6-h. By comparing the superior and inferior groups within these 64 ensembles, we confirmed the influence of the Atlantic in the West Sahel rainfall (a robust feature in the ensembles) and a severe model bias resulting from erroneously modeled locations and magnitudes of low-level Sahara heat low (SHL) and African easterly jet (AEJ). This bias is highly related to atmospheric jet dynamics as shown in recent studies and local wave instability triggered mainly by the boundary-layer temperature gradient and amplified by land-atmosphere interactions. In particular, our results demonstrated that more accurate divergence and convergence fields resulting from improved SHL and AEJ in the superior groups enabled more accurate rainbelt patterns to be discerned, thus improving the ensemble mean model hindcast prediction by more than 25 % in precipitation and 16 % in temperature. We concluded that the use of low-resolution climate models to project future rainfall in the Sahel requires caution because the model hindcasts may quickly diverge even the same boundary conditions and forcings are applied. The model bias may easily grow up within a few months in the short-range CAM-LETKF hindcast, let along the free model centennial simulations. Unconstrained future climate model projections for the Sahel must more effectively capture the short-term key boundary-layer dynamics in the boreal summer to be credible regardless model dynamics

  2. Acid Rain Examination and Chemical Composition of Atmospheric Precipitation in Tehran, Iran

    Directory of Open Access Journals (Sweden)

    Mohsen Saeedi

    2012-01-01

    Full Text Available Air pollution is one of the most important environmental problems in metropolitan cities like Tehran. Rain and snow, as natural events, may dissolve and absorb contaminants of the air and direct them onto the land or surface waters which become polluted. In the present study, precipitation samples were collected from an urbanized area of Tehran. They were analyzed for NO3-, PO43-, SO42-, pH, turbidity, Electrical Conductivity (EC, Cu, Fe, Zn, Pb, Ni, Cr, and Al. We demonstrate that snow samples were often more polluted and had lower pH than those from the rain, possibly as an effect of adsorption capability of snow flakes. Volume weighted average concentrations were calculated and compared with some other studies. Results revealed that Tehran's precipitations are much more polluted than those reported from other metropolitan cities. Cluster analysis revealed that studied parameters such as metals and acidity originated from the same sources, such as fuel combustion in residential and transportation sectors of Tehran.

  3. Diagnosing links between atmospheric moisture and extreme daily precipitation over the UK

    OpenAIRE

    Richard P Allan; Lavers, David A.; Champion, Adrian J.

    2016-01-01

    Atmospheric moisture characteristics associated with the heaviest 1% of daily rainfall events affecting regions of the British Isles are analysed over the period 1997–2008. A blended satellite/rain-gauge data set (GPCP-1DD) and regionally averaged daily rain-gauge observations (HadUKP) are combined with the ERA Interim reanalysis. These are compared with simulations from the HadGEM2-A climate model which applied observed sea surface temperature and realistic radiative forcings. Median extreme...

  4. Assessment of sources and pathways of atmospheric contaminants in precipitation over central Bohemia

    Czech Academy of Sciences Publication Activity Database

    Vach, Marek; Fišák, Jaroslav; Skřivan, Petr

    2004-01-01

    Roč. 68, 11S (2004), A461-A461. ISSN 0046-564X. [Annual V. M. Goldschmidt Conference /14./. 05.06.2004-11.06.2004, Copenhagen] R&D Projects: GA ČR(CZ) GA205/04/0060 Institutional research plan: CEZ:AV0Z3013912; CEZ:AV0Z3042911 Keywords : atmosphere * deposition * chemistry Subject RIV: DD - Geochemistry

  5. Atmospheric and precipitation sounding with polarimetric radio-occultations aboard PAZ LEO

    Science.gov (United States)

    Padulles, Ramon; Cardellach, Estel; Tomás, Sergio; Oliveras, Santi; Rius, Antonio; de la Torre, Manuel; Turk, Joseph; Ao, Chi; Kursinski, Robert; Shreiner, Bill; Ector, Dave; Cucurull, Lidia; Wickert, Jens

    2015-04-01

    The Radio Occultation and Heavy Precipitation experiment aboard the PAZ Low Earth Orbiter (ROHP-PAZ) is a mission of opportunity: The Spanish Ministry of Science and Innovation (MICINN) approved in 2009 a proposal to include a polarimetric Global Navigation Satellite System (GNSS) Radio-Occultation (RO) payload on board of the Spanish Earth Observation satellite PAZ. This will be a new technique that has never been tested before, that aims to improve the knowledge of the precipitation through simultaneous thermodynamic and vertical rain profiles. The concept is similar to that used in some polarimetric weather radars: to measure the differential phase shift between the two polarimetric antennas, although here we will use the forward scattering geometry instead of the backscattering.The depolarization effect increases as the propagation line aligns with the plane of the drops' flattening (nominally perpendicular to the local gravity, i.e., parallel to the local horizon). The RO signals cross the lower troposphere tangentially, i.e., along the local horizon, which should maximize the depolarization effect. The satellite launch is scheduled for March 2015, and it will be followed by a 6-month commissioning phase period and has an expected life of 7 years, with a goal of 10 years. A sensitivity analysis have been performed, showing that we should be able to detect the 90% of all the events with along-ray averaged rain rate higher than 5 mm/h. Also, a ground field campaign has been conducted prior to the launch of the satellite. Results from the campaign also show a good correlation between phase shifts increases and heavy rain events. We will present here the status of the mission, which will have been launched few weeks before the EGU, together with some preliminary data analysis from both the actual satellite data and the prior-to-launch work.

  6. Chemistry of atmospheric precipitation in the north-central united states: Influence of sulfate, nitrate, ammonia and calcareous soil particulates

    Science.gov (United States)

    Munger, James William

    The supply of alkaline soil dust and gaseous NH 3 available to neutralize anthropogenic acids in the atmosphere controls the acidity of precipitation in the north-central United States. Major ions and trace metals were determined in precipitation-event and snow-core samples from sites along a 600 km transect from the North Dakota prairie to the forests of northeastern Minnesota, collected during the period April 1978-June 1979. Acidity increased 4-fold from west to east as the effect of alkaline dust and NH 3 decreased with increasing distance from the cultivated prairie; calcium and Mg 2+ decreased 2 to 3-fold across the transect. However, minimum concentrations of NH 4+ and SO 42- were observed at Itasca, the central site. Natural emissions of these elements were important in the west, while anthropogenic emissions were responsible for the higher concentrations in the east. Wet deposition of H + decreased 8-fold and deposition of NO 3- and SO 42- decreased 1.5 to 2-fold from Hovland in the east to Tewaukon in the west. Wet deposition of the metal cations increased from Hovland to Tewaukon. Dry deposition followed a similar trend. Winter snow cover and freezing temperatures, which decreased airborne soil dust and the evolution of NH 3 from the prairie soils, led to an increase in precipitation acidity at all sites. The acid increase was accompanied by a decrease in alkaline metal cations, especially Ca 2+, and in NH 4+. At Hovland SO 42- and NO 3- also increased during the winter. The occurrence of snow events at Tewaukon that were appreciably more acid than the snowpack accumulated there indicates that snow was neutralized after it fell by alkaline dust entrained in resuspended snow, or deposited separately. Winter inputs of acid are especially important because they are released during a short period in the spring. Over half of the acid input at Hovland occurred during the winter. Precipitation inputs of P and N probably benefit nutrient-poor ecosystems in the

  7. Estimating precipitation on early Mars using a radiative-convective model of the atmosphere and comparison with inferred runoff from geomorphology

    CERN Document Server

    von Paris, P; Grenfell, J L; Hauber, E; Breuer, D; Jaumann, R; Rauer, H; Tirsch, D

    2014-01-01

    We compare estimates of atmospheric precipitation during the Martian Noachian-Hesperian boundary 3.8 Gyr ago as calculated in a radiative-convective column model of the atmosphere with runoff values estimated from a geomorphological analysis of dendritic valley network discharge rates. In the atmospheric model, we assume CO2-H2O-N2 atmospheres with surface pressures varying from 20 mb to 3 bar with input solar luminosity reduced to 75% the modern value. Results from the valley network analysis are of the order of a few mm d-1 liquid water precipitation (1.5-10.6 mm d-1, with a median of 3.1 mm d-1). Atmospheric model results are much lower, from about 0.001-1 mm d-1 of snowfall (depending on CO2 partial pressure). Hence, the atmospheric model predicts a significantly lower amount of precipitated water than estimated from the geomorphological analysis. Furthermore, global mean surface temperatures are below freezing, i.e. runoff is most likely not directly linked to precipitation. Therefore, our results strong...

  8. Millimeter-wave imaging radiometer for cloud, precipitation and atmospheric water vapor studies

    Science.gov (United States)

    Racette, P. E.; Dod, L. R.; Shiue, J. C.; Adler, R. F.; Jackson, D. M.; Gasiewski, A. J.; Zacharias, D. S.

    1992-01-01

    A millimeter-wave imaging radiometer (MIR) developed by NASA Goddard Space Flight Center is described. The MIR is a nine-channel total power radiometer developed for atmospheric research. Three dual-pass band channels are centered about the strongly opaque 183-GHz water vapor absorption line; the frequencies are 183 +/- 1, +/- 3, and +/- 7 GHz. Another channel is located on the wing of this band at 150 GHz. These four channels have varying degrees of opacity from which the water vapor profile can be inferred. The design and salient characteristics of this instrument are discussed, together with its expected benefits.

  9. Neptunium oxide precipitation kinetics in aqueous systems at elevated temperatures. Part I: Colloidal, temperature, inert atmosphere, and ionic strength measurements

    International Nuclear Information System (INIS)

    We evaluate the proposed NpO2+(aq)-NpO2(cr) reduction-precipitation system at elevated temperatures to obtain primary information on the effects of temperature, ionic strength, O2 and CO2. Experiments conducted on unfiltered solutions at 10-4 M NpO2+(aq), neutral pH, and 200 C indicated that solution colloids strongly affect precipitation kinetics. Subsequent experiments on filtered solutions at 200, 212, and 225 C showed consistent and distinctive temperature-dependent behavior at reaction times (le) 800 hours. At longer times, the 200 C experiments showed unexpected dissolution of neptunium solids, but experiments at 212 C and 225 C demonstrated quasi steady-state neptunium concentrations of 3 x 10-6 M and 6 x 10-6 M, respectively. Solids from a representative experiment analyzed by X-ray diffraction were consistent with NpO2(cr). A 200 C experiment with a NaCl concentration of 0.05 M showed a dramatic increase in the rate of neptunium loss. A 200 C experiment in an argon atmosphere resulted in nearly complete loss of aqueous neptunium. Previously proposed NpO2+(aq)-NpO2(cr) reduction-precipitation mechanisms in the literature specified a 1:1 ratio of neptunium loss and H+ production in solution over time. However, all experiments demonstrated ratios of approximately 0.4 to 0.5. Carbonate equilibria can account for only about 40% of this discrepancy, leaving an unexpected deficit in H+ production that suggests that additional chemical processes are occurring.

  10. Lagged effects of the Mistral wind on heavy precipitation through ocean-atmosphere coupling in the region of Valencia (Spain)

    Science.gov (United States)

    Berthou, Ségolène; Mailler, Sylvain; Drobinski, Philippe; Arsouze, Thomas; Bastin, Sophie; Béranger, Karine; Lebeaupin Brossier, Cindy

    2016-05-01

    The region of Valencia in Spain has historically been affected by heavy precipitation events (HPEs). These HPEs are known to be modulated by the sea surface temperature (SST) of the Balearic Sea. Using an atmosphere-ocean regional climate model, we show that more than 70 % of the HPEs in the region of Valencia present a SST cooling larger than the monthly trend in the Northwestern Mediterranean before the HPEs. This is linked to the breaking of a Rossby wave preceding the HPEs: a ridge-trough pattern at mid-levels centered over western France associated with a low-level depression in the Gulf of Genoa precedes the generation of a cut-off low over southern Spain with a surface depression over the Alboran Sea in the lee of the Atlas. This latter situation is favourable to the advection of warm and moist air towards the Mediterranean Spanish coast, possibly leading to HPEs. The depression in the Gulf of Genoa generates intense northerly (Mistral) to northwesterly (Tramontane/Cierzo) winds. In most cases, these intense winds trigger entrainment at the bottom of the oceanic mixed layer which is a mechanism explaining part of the SST cooling in most cases. Our study suggests that the SST cooling due to this strong wind regime then persists until the HPEs and reduces the precipitation intensity.

  11. Sensitivity of precipitation to parameter values in the community atmosphere model version 5

    Energy Technology Data Exchange (ETDEWEB)

    Johannesson, Gardar [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lucas, Donald [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Qian, Yun [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Swiler, Laura Painton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wildey, Timothy Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-03-01

    One objective of the Climate Science for a Sustainable Energy Future (CSSEF) program is to develop the capability to thoroughly test and understand the uncertainties in the overall climate model and its components as they are being developed. The focus on uncertainties involves sensitivity analysis: the capability to determine which input parameters have a major influence on the output responses of interest. This report presents some initial sensitivity analysis results performed by Lawrence Livermore National Laboratory (LNNL), Sandia National Laboratories (SNL), and Pacific Northwest National Laboratory (PNNL). In the 2011-2012 timeframe, these laboratories worked in collaboration to perform sensitivity analyses of a set of CAM5, 2° runs, where the response metrics of interest were precipitation metrics. The three labs performed their sensitivity analysis (SA) studies separately and then compared results. Overall, the results were quite consistent with each other although the methods used were different. This exercise provided a robustness check of the global sensitivity analysis metrics and identified some strongly influential parameters.

  12. Aerosol optical properties and precipitable water vapor column in the atmosphere of Norway.

    Science.gov (United States)

    Muyimbwa, Dennis; Frette, Øyvind; Stamnes, Jakob J; Ssenyonga, Taddeo; Chen, Yi-Chun; Hamre, Børge

    2015-02-20

    Between February 2012 and April 2014, we measured and analyzed direct solar radiances at a ground-based station in Bergen, Norway. We discovered that the spectral aerosol optical thickness (AOT) and precipitable water vapor column (PWVC) retrieved from these measurements have a seasonal variation with highest values in summer and lowest values in winter. The highest value of the monthly median AOT at 440 nm of about 0.16 was measured in July and the lowest of about 0.04 was measured in December. The highest value of the monthly median PWVC of about 2.0 cm was measured in July and the lowest of about 0.4 cm was measured in December. We derived Ångström exponents that were used to deduce aerosol particle size distributions. We found that coarse-mode aerosol particles dominated most of the time during the measurement period, but fine-mode aerosol particles dominated during the winter seasons. The derived Ångström exponent values suggested that aerosols containing sea salt could have been dominating at this station during the measurement period. PMID:25968219

  13. Interaction of Convective Organization and Monsoon Precipitation, Atmosphere, Surface and Sea (INCOMPASS)

    Science.gov (United States)

    Turner, Andrew; Bhat, Gs; Evans, Jonathan; Marsham, John; Martin, Gill; Parker, Douglas; Taylor, Chris; Bhattacharya, Bimal; Madan, Ranju; Mitra, Ashis; Mrudula, Gm; Muddu, Sekhar; Pattnaik, Sandeep; Rajagopal, En; Tripathi, Sachida

    2015-04-01

    The monsoon supplies the majority of water in South Asia, making understanding and predicting its rainfall vital for the growing population and economy. However, modelling and forecasting the monsoon from days to the season ahead is limited by large model errors that develop quickly, with significant inter-model differences pointing to errors in physical parametrizations such as convection, the boundary layer and land surface. These errors persist into climate projections and many of these errors persist even when increasing resolution. At the same time, a lack of detailed observations is preventing a more thorough understanding of monsoon circulation and its interaction with the land surface: a process governed by the boundary layer and convective cloud dynamics. The INCOMPASS project will support and develop modelling capability in Indo-UK monsoon research, including test development of a new Met Office Unified Model 100m-resolution domain over India. The first UK detachment of the FAAM research aircraft to India, in combination with an intensive ground-based observation campaign, will gather new observations of the surface, boundary layer structure and atmospheric profiles to go with detailed information on the timing of monsoon rainfall. Observations will be focused on transects in the northern plains of India (covering a range of surface types from irrigated to rain-fed agriculture, and wet to dry climatic zones) and across the Western Ghats and rain shadow in southern India (including transitions from land to ocean and across orography). A pilot observational campaign is planned for summer 2015, with the main field campaign to take place during spring/summer 2016. This project will advance our ability to forecast the monsoon, through a programme of measurements and modelling that aims to capture the key surface-atmosphere feedback processes in models. The observational analysis will allow a unique and unprecedented characterization of monsoon processes that

  14. Comparative Experimental Investigation of Titan's Atmospheric Chemistry Driven by Solar EUV Radiation and Energetic Electron Precipitation

    Science.gov (United States)

    Imanaka, Hiroshi; Lavvas, P.; Yelle, R. V.; Smith, M. A.

    2010-10-01

    The observations by the Cassini Ion Neutral Mass Spectrometer (INMS) and the Cassini Plasma Spectrometer (CAPS) clearly demonstrate the importance of complex organic chemistry in the upper atmosphere of Titan; a complex coupling of neutral and ion chemistry for organic aerosol generation induced by EUV photons and Saturn's magnetospheric charged particles. To understand the dominant energy source for aerosol formation and its formation chemistry, we comparatively investigate the chemical mechanism in N2/CH4 gas mixtures resulting from EUV-VUV synchrotron radiation (50-150 nm) and tunable mono-energetic electron beam irradiation (5 eV - 2000 eV). These excitation energy sources cover the dominant energy source available in Titan's upper atmosphere. Our previous study of the EUV-VUV photolysis of N2/CH4 gas mixtures revealed the unique role of nitrogen photoionization in the catalytic formation of complex hydrocarbons and in the major nitrogen fixation process in Titan's upper atmosphere (Imanaka and Smith, 2007, 2009, 2010). However, relative roles of ion-molecule reactions and radical/neutral reactions in such complex chemistry remain to be determined. We characterized the electron energy distribution by conducting the Langmuir probe measurements. Degradation of the primary photoelectron from N2 photoionization at 20.6 eV photons is clearly observed, and the electron density rapidly decreases down to 109-10 cm-3, which suggests the complex coupling of ion-molecular reactions and dissociative ion-electron recombination reactions for the observed development of complex organic molecules. The electron beam irradiation experiments at energy larger than 200 eV shows distinct gaseous product distribution with nitrogenated gaseous species from those with EUV irradiation products. The generation of secondary electrons and multiple inelastic collisions of fast electrons might increases the nitrogen fixation efficiency. The much less stringent spin selection rules could

  15. Study on the changes in the East Asian precipitation in the mid-1990s using a high-resolution global downscaled atmospheric data set

    Science.gov (United States)

    Chang, Eun-Chul; Yeh, Sang-Wook; Hong, Song-You; Kim, Jung-Eun; Wu, Renguang; Yoshimura, Kei

    2014-03-01

    A high-resolution global atmospheric data set (DA126) is used to understand the East Asian summer precipitation variability. It is found that a fine resolution of the DA126 precipitation data is able to reveal the detailed structures of the rainfall variability over East Asia and southern China in comparison with global analysis precipitation data sets such as the Climate Prediction Center Merged Analysis of Precipitation (CMAP). The first two empirical orthogonal functions (EOFs) of the DA126 precipitation data over East Asia accurately reflect a decadal shift in rainfall over southern China in the mid-1990s. Furthermore, the first EOF-related precipitation of the DA126 is related to the tropical Pacific sea surface temperature (SST) variability (i.e., El Niño/Southern Oscillation), and the second EOF-related precipitation is associated with the Indian Ocean SST variability. Consequently, the tropical Pacific and the Indian Ocean SSTs have different associations with the East Asian monsoon precipitation variability. However, it is difficult to find such a relationship in the first two EOFs of the CMAP data set over East Asia. Using the DA126 precipitation data set, our further analysis indicates that warming of both the tropical Pacific and the Indian Ocean causes an increase in the rainfall anomaly over southern China after the mid-1990s, which results in a decadal shift in the rainfall anomaly after the mid-1990s. In addition, the first EOF-related precipitation is associated with both the Pacific-Japan-like (PJ-like) pattern and the Eurasian-like pattern. In contrast, the second EOF-related precipitation is only associated with the PJ-like wave trains from the western Pacific to East Asia.

  16. Changes in precipitation intensity over East Asia during the 20th and 21st centuries simulated by a global atmospheric model with a 60 km grid size

    Science.gov (United States)

    Kusunoki, Shoji; Mizuta, Ryo

    2013-10-01

    We conducted three-member ensemble simulations using a global atmospheric model with a high horizontal resolution of a 60 km grid size for the period 1872-2099 (228 years). Between 1872 and 2005, the model was forced with observed historical sea surface temperatures (SST), while between 2006 and 2099, the boundary SST data were estimated using the multimodel ensemble of the Coupled Model Intercomparison Project Phase 3 models and assuming A1B emission scenario. Annual mean precipitation (PAVE), the Simple Daily Precipitation Intensity Index (SDII), and the maximum 5 day precipitation total (R5d) averaged over East Asia increase almost monotonically through the 21st century. The statistically significant area of precipitation intensity increase is larger for 2080-2099 than for 2046-2065. In particular, intense rainfall will increase over northern and southern China during 2080-2099. The conversion rate from water vapor to precipitation per 1°C rise in surface air temperature for SDII and R5D is much larger than that for PAVE during the 21st century. This suggests that extreme rainfall events will occur more frequently than moderate rainfall events even if the amount of temperature rise is same. Future changes in the horizontal transport of water vapor also lead to more intense precipitation over East Asia. In particular, the increase in clockwise water vapor transport due to intensification of the subtropical high contributes to increased intense precipitation over southern China.

  17. Orographic cyclogenesis in a saturated atmosphere and intense precipitation: baroclinic modal solutions under the joint action of localized mountains and humidity

    Directory of Open Access Journals (Sweden)

    A. Speranza

    1997-06-01

    Full Text Available In this paper we analyse the nature of orographic cyclogenesis in a saturated atmosphere by means of a simplified model based on the analysis of linear modal solutions.The space structure of fastest growing modal solutions suggests that three different scales of axtratropical atmospheric motion may simultaneously be activated in a single, growing, unstable mode: the orographic modulation of growing baroclinic modes extending, as we know from the classical modal theory of orographic cyclogenesis, from the scale typical of the primary, extra-tropical cyclone to the scale of the secondary, orographic cyclone, is also characterized by the (smaller scale associated with strong ascending motion in a saturated atmosphere. Since ascending motion can be associated with intense precipitation, this result is important in view of its potential consequences both on the ability to achieve a good forecast of intense precipitation events in the Mediterranean and on the refinement of the theory of orographic cyclogenesis.

  18. The global distribution of natural tritium in precipitation simulated with an Atmospheric General Circulation Model and comparison with observations

    Science.gov (United States)

    Cauquoin, A.; Jean-Baptiste, P.; Risi, C.; Fourré, É.; Stenni, B.; Landais, A.

    2015-10-01

    The description of the hydrological cycle in Atmospheric General Circulation Models (GCMs) can be validated using water isotopes as tracers. Many GCMs now simulate the movement of the stable isotopes of water, but here we present the first GCM simulations modelling the content of natural tritium in water. These simulations were obtained using a version of the LMDZ General Circulation Model enhanced by water isotopes diagnostics, LMDZ-iso. To avoid tritium generated by nuclear bomb testing, the simulations have been evaluated against a compilation of published tritium datasets dating from before 1950, or measured recently. LMDZ-iso correctly captures the observed tritium enrichment in precipitation as oceanic air moves inland (the so-called continental effect) and the observed north-south variations due to the latitudinal dependency of the cosmogenic tritium production rate. The seasonal variability, linked to the stratospheric intrusions of air masses with higher tritium content into the troposphere, is correctly reproduced for Antarctica with a maximum in winter. LMDZ-iso reproduces the spring maximum of tritium over Europe, but underestimates it and produces a peak in winter that is not apparent in the data. This implementation of tritium in a GCM promises to provide a better constraint on: (1) the intrusions and transport of air masses from the stratosphere, and (2) the dynamics of the modelled water cycle. The method complements the existing approach of using stable water isotopes.

  19. THE ASSESSMENT OF ATMOSPHERIC DROUGHT DURING VEGETATION SEASON (ACCORDING TO STANDARDIZED PRECIPITATION INDEX SPI IN CENTRAL-EASTERN POLAND

    Directory of Open Access Journals (Sweden)

    Elżbieta Radzka

    2014-12-01

    Full Text Available The paper presents an assessment of atmospheric drought during vegetation season defined on the basis of standardized precipitation index (SPI. The data used in this paper come from nine IMWM stations from central-eastern region of Poland, and they were registered in 1971–2005. The frequency of occurrence of vegetation season’s months was determined in particular drought classes. Spatial distribution of SPI index values was shown in all of the vegetation season’s months on the area examined. The direction and significance of values changes tendency of the analyzed index during the vegetation season were also defined. It was noticed that extreme droughts appeared four times less frequently than the normal months. Very dry months were noted most frequently in September while moderately dry – in August. The analysis of the frequency of spatial distribution of particular drought classes showed that extreme dry and very dry months occurred most frequently in western part of the area examined, while the moderately dry months also in south-eastern part. On the basis of the linear trend analysis it can be said that the SPI index values were slightly decreasing year by year.

  20. Precipitation, atmospheric deposition, streamflow, and water-quality data from selected sites in the city of Charlotte and Mecklenburg County, North Carolina, 1997-98

    Science.gov (United States)

    Sarver, Kathleen M.; Hazell, W.F.; Robinson, J.B.

    1999-01-01

    Precipitation data were collected at 46 precipitation sites and 3 atmospheric deposition sites, and hydrologic data were collected at 6 stream sites in the vicinity of Charlotte and Mecklenburg County, North Carolina, from July 1997 through September 1998. Data were collected to identify the type, concentration, and amount of nonpoint- source stormwater runoff in the study area. The data collected include measurements of precipitation; streamflow; physical characteristics, such as water temperature, pH, specific conductance, biochemical oxygen demand, oil and grease, and suspended-sediment concentrations; and concentrations of nutrients, metals and minor constituents, and organic compounds. These data will provide information needed for (1) planned watershed simulation models, (2) estimates of nonpoint-source constituent loadings to the Catawba River, and (3) characterization of water quality in relation to basin conditions. Streamflow and rainfall data have been used to provide early warnings of possible flooding.

  1. Atmospheric balance of the humidity and estimate of the precipitation recycled in Colombia according to the re-analysis NCEP/NCAR

    International Nuclear Information System (INIS)

    The magnitudes of the entrance humidity flows and exit are considered and the amount of precipitable water at different levels from the atmospheric column on Colombia. The water balance is quantified in the Colombian atmosphere; the regions and the atmospheric levels of entrance and exit of humidity are identified. The hypothesis that in the long term the net atmospheric humidity influence must be equal to the average of long term of the net run-off is verified. In addition, the percentage of recycled precipitation is considered on the Colombian territory. The variability during the two phases of the ENSO is analyzed. The calculations are made with the information of the climatic project Reanalysis developed by the National Center for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR), with the collaboration of the National Oceanic and Atmospheric Administration (NOAA)/National Environmental Satellite of the U.S.A. For this work it was counted on monthly information of 41 years between 1958-1998. The hydrological information was obtained from the project Balances Hidrologicos de Colombia, 1999, made by the Posgrado de Recursos Hidraulicos, de la Universidad Nacional, with the support of COLCIENCIAS and the Unidad de Planeacion Minero Energetica-UPME. The results showed the average value of the net influence of humidity to the atmosphere of Colombia is of 5716 mm/year, with a great variability in both phases of the ENSO. The greater humidity advection towards Colombia occurs in the low levels of pressure (between 1000 and 850 hPa), and originating of all the directions, mainly of trade winds of the east and trade winds of the west. Also one was that the greater humidity transport towards Colombia occurs in trimesters DJF and MAM, with average values 505,1 and 606,6 mm/year, respectively. It was observed that the hypothesis that in the long term, the net atmospheric flux, is equal to the net terrestrial run-off, reasonably is adapted for

  2. Impact of horizontal resolution on simulation of precipitation extremes in an aqua-planet version of the Community Atmosphere Model (CAM)

    Energy Technology Data Exchange (ETDEWEB)

    Li, F.; Collins, W.D.; Wehner, M.F.; Williamson, D.L.; Olson, J.G.; Algieri, C.

    2011-03-01

    One key question regarding current climate models is whether the projection of climate extremes converges to a realistic representation as the spatial and temporal resolutions of the model are increased. Ideally the model extreme statistics should approach a fixed distribution once the resolutions are commensurate with the characteristic length and time scales of the processes governing the formation of the extreme phenomena of interest. In this study, a series of AGCM runs with idealized 'aquaplanet-steady-state' boundary conditions have been performed with the Community Atmosphere Model CAM3 to investigate the effect of horizontal resolution on climate extreme simulations. The use of the aquaplanet framework highlights the roles of model physics and dynamics and removes any apparent convergence in extreme statistics due to better resolution of surface boundary conditions and other external inputs. Assessed at a same large spatial scale, the results show that the horizontal resolution and time step have strong effects on the simulations of precipitation extremes. The horizontal resolution has a much stronger impact on precipitation extremes than on mean precipitation. Updrafts are strongly correlated with extreme precipitation at tropics at all the resolutions, while positive low-tropospheric temperature anomalies are associated with extreme precipitation at mid-latitudes.

  3. Spring soil moisture-precipitation feedback in the Southern Great Plains: How is it related to large-scale atmospheric conditions?

    KAUST Repository

    Su, Hua

    2014-02-22

    The Southern Great Plains (SGP) has been shown as a region of significant soil moisture-precipitation (S-P) coupling. However, how strong evapotranspiration (ET) can affect regional precipitation remains largely unclear, impeding a full grasp of the S-P feedback in that area. The current study seeks to unravel, in a spring month (April), the potential role played by large-scale atmospheric conditions in shaping S (ET)-P feedback. Our regional climate modeling experiments demonstrate that the presence of anomalous low (high) pressure and cyclonic (anticyclonic) flows at the upper/middle troposphere over the relevant areas is associated with strongest (minimum) positive S-P feedback in the SGP. Their impacts are interpreted in terms of large-scale atmospheric dynamical disturbance, including the intensity and location of synoptic eddies. Further analyses of the vertical velocity fields corroborate these interpretations. In addition, the relationship between lower tropospheric moisture conditions (including winds) and feedback composites is evaluated. Key Points The S-P feedback strength in SGP in April varies inter-annually The atmospheric dynamic features affect significantly the feedback strength composite moisture conditions are related to atmospheric circulation structure ©2014. American Geophysical Union. All Rights Reserved.

  4. The groundwater buffering effect on heat waves and precipitation: coupled groundwater-atmosphere simulations over Europe and North America with a WRF-LEAFHYDRO system.

    Science.gov (United States)

    Miguez-Macho, Gonzalo; Gómez, Breogán; Regueiro-Sanfiz, Sabela; Georgescu, Matei

    2016-04-01

    We present coupled atmosphere-hydrology simulations with the WRF regional climate model and the LEAFHYDRO LSM, including groundwater dynamics. Simulations are carried out for the coupled system for the growing season (February to October) over Europe at 2.5km resolution over land and 20km over the atmosphere. Initial conditions for the land surface, groundwater and rivers are from 10 year off-line simulations, performed continuously over the same domain and period, forced by atmospheric data from the Earth2Observe FP7 project. We show that the presence of a shallow water table over portions of the European continent enhances evapotranspiration in dry periods under increasing atmospheric demand. The impact of the coupling between groundwater and the soil vegetation system on land surface fluxes results in decreases in air temperature and an increase in low level mixing ratios, which under certain convective regimes induces more precipitation. We illustrate for the heat wave of 2003 that models that do not include this groundwater buffering effect may enhance significantly the intensity of such temperature extreme cases. The effect on precipitation is mostly seen over inland areas where warm season convection is important. We show with results of additional simulations over North America, where summer convection over the interior of the continent is very relevant, that the effect of groundwater-enhanced evapotranspiration may have a sizeable impact on climate at the global scale.

  5. Long Lead-Time Forecasting of Snowpack and Precipitation in the Upper Snake River Basin using Pacific Oceanic-Atmospheric Variability

    Science.gov (United States)

    Anderson, S.; Tootle, G.; Parkinson, S.; Holbrook, P.; Blestrud, D.

    2012-12-01

    Water managers and planners in the western United States are challenged with managing resources for various uses, including hydropower. Hydropower is especially important throughout the Upper Snake River Basin, where a series of hydropower projects provide a low cost renewable energy source to the region. These hydropower projects include several dams that are managed by Idaho Power Company (IPC). Planners and managers rely heavily on forecasts of snowpack and precipitation to plan for hydropower availability and the need for other generation sources. There is a pressing need for improved snowpack and precipitation forecast models in the Upper Snake River Basin. This research investigates the ability of Pacific oceanic-atmospheric data and climatic variables to provide skillful long lead-time (three to nine months) forecasts of snowpack and precipitation, and examines the benefits of segregating the warm and cold phases of the Pacific Decadal Oscillation (PDO) to reduce the temperature variability within the target dataset. Singular value decomposition (SVD) was used to identify regions of Pacific Ocean sea surface temperatures (SST) and 500mbar geopotential heights (Z500) for various lead times (three, six, and nine months) that were teleconnected with snowpack and precipitation stations in Upper Snake River Basin headwaters. The identified Pacific Ocean SST and Z500 regions were used to create indices that became predictors in a non-parametric forecasting model. The majority of forecasts resulted in positive statistical skill, which indicated an improvement of the forecast over the climatology forecast (no-skill forecast). The results from the forecasts models indicated that derived indices from the SVD analysis resulted in improved forecast skill when compared to forecasts using established climate indices. Segregation of the cold phase PDO years resulted in the identification of different regions in the Pacific Ocean and vastly improved skill for the nine month

  6. Reconstructions of spring/summer precipitation for the Eastern Mediterranean from tree-ring widths and its connection to large-scale atmospheric circulation

    Energy Technology Data Exchange (ETDEWEB)

    Touchan, Ramzi; Funkhouser, Gary; Hughes, Malcolm K. [The University of Arizona, Laboratory of Tree-Ring Research, Tucson, AZ (United States); Xoplaki, Elena; Luterbacher, Juerg [University of Bern, Institute of Geography and NCCR Climate, Bern (Switzerland); Erkan, Nesat [Southwest Anatolia Forest Research Institute (SAFRI), Antalya (Turkey); Akkemik, Uenal [University of Istanbul, Faculty of Forestry, Department of Forest Botany, Bahcekoey-Istanbul (Turkey); Stephan, Jean [Ministry of Agriculture, Forestry Department, Beirut (Lebanon)

    2005-07-01

    This study represents the first large-scale systematic dendroclimatic sampling focused on developing chronologies from different species in the eastern Mediterranean region. Six reconstructions were developed from chronologies ranging in length from 115 years to 600 years. The first reconstruction (1885-2000) was derived from principal components (PCs) of 36 combined chronologies. The remaining five, 1800-2000, 1700-2000, 1600-2000, 1500-2000 and 1400-2000 were developed from PCs of 32, 18, 14, 9, and 7 chronologies, respectively. Calibration and verification statistics for the period 1931-2000 show good levels of skill for all reconstructions. The longest period of consecutive dry years, defined as those with less than 90% of the mean of the observed May-August precipitation, was 5 years (1591-1595) and occurred only once during the last 600 years. The longest reconstructed wet period was 5 years (1601-1605 and 1751-1755). No long term trends were found in May-August precipitation during the last few centuries. Regression maps are used to identify the influence of large-scale atmospheric circulation on regional precipitation. In general, tree-ring indices are influenced by May-August precipitation, which is driven by anomalous below (above) normal pressure at all atmospheric levels and by convection (subsidence) and small pressure gradients at sea level. These atmospheric conditions also control the anomaly surface air temperature distribution which indicates below (above) normal values in the southern regions and warmer (cooler) conditions north of around 40 N. A compositing technique is used to extract information on large-scale climate signals from extreme wet and dry summers for the second half of the twentieth century and an independent reconstruction over the last 237 years. Similar main modes of atmospheric patterns and surface air temperature distribution related to extreme dry and wet summers were identified both for the most recent 50 years and the last

  7. Influence of SST from Pacific and Atlantic Ocean and atmospheric circulation in the precipitation regime of basin from Brazilian SIN

    Science.gov (United States)

    Custodio, M. D.; Ramos, C. G.; Madeira, P.; de Macedo, A. L.

    2013-12-01

    The South American climate presents tropical, subtropical and extratropical features because of its territorial extension, being influenced by a variety of dynamical systems with different spatial and temporal scales which result in different climatic regimes in their subregions. Furthermore, the precipitation regime in South America is influenced by low-frequency phenomena as El Niño-Southern Oscillation (ENSO), the Atlantic dipole and the Madden Julian Oscilation (MJO), in other words, is directly influenced by variations of the Sea Surface Temperature (SST). Due to the importance of the precipitation for many sectors including the planning of productive activities, such as agriculture, livestock and hydropower energy, many studies about climate variations in Brazil have tried to determine and explain the mechanisms that affect the precipitation regime. However, because of complexity of the climate system, and consequently of their impacts on the global precipitation regime, its interactions are not totally understood and therefore misrepresented in numerical models used to forecast climate. The precipitation pattern over hydrographic basin which form the Brasilian National Interconnected System (Sistema Interligado Nacional-SIN) are not yet known and therefore the climate forecast of these regions still presents considerable failure that need to be corrected due to its economic importance. In this context, the purpose here is to determine the precipitation patterns on the Brazilian SIN, based on SST and circulation observed data. In a second phase a forecast climate model for these regions will be produced. In this first moment 30 years (1983 to 2012) of SST over Pacific and Atlantic Ocean were analyzed, along with wind in 850 and 200 hPa and precipitation observed data. The precipitation patterns were analyzed through statistical analyses for interannual (ENSO) and intraseasonal (MJO) anomalies for these variables over the SIN basin. Subsequently, these

  8. A Projection of Changes in Landfilling Atmospheric River Frequency and Extreme Precipitation over Western North America from the Large Ensemble CESM Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Hagos, Samson M.; Leung, Lai-Yung R.; Yoon, Jin-Ho; Lu, Jian; Gao, Yang

    2016-02-06

    Simulations from the Community Earth System Model Large Ensemble project are analyzed to investigate the impact of global warming on atmospheric rivers (ARs). The model has notable biases in simulating the subtropical jet position and the relationship between extreme precipitation and moisture transport. After accounting for these biases, the model projects an ensemble mean increase of 35% in the number of landfalling AR days between the last twenty years of the 20th and 21st centuries. However, the number of AR associated extreme precipitation days increases only by 28% because the moisture transport required to produce extreme precipitation also increases with warming. Internal variability introduces an uncertainty of ±8% and ±7% in the projected changes in AR days and associated extreme precipitation days. In contrast, accountings for model biases only change the projected changes by about 1%. The significantly larger mean changes compared to internal variability and to the effects of model biases highlight the robustness of AR responses to global warming.

  9. Low-frequency variations in surface atmospheric humidity, temperature, and precipitation: Inferences from reanalyses and monthly gridded observational data sets

    Science.gov (United States)

    Simmons, A. J.; Willett, K. M.; Jones, P. D.; Thorne, P. W.; Dee, D. P.

    2010-01-01

    Evidence is presented of a reduction in relative humidity over low-latitude and midlatitude land areas over a period of about 10 years leading up to 2008, based on monthly anomalies in surface air temperature and humidity from comprehensive European Centre for Medium-Range Weather Forecasts reanalyses (ERA-40 and ERA-Interim) and from Climatic Research Unit and Hadley Centre analyses of monthly station temperature data (CRUTEM3) and synoptic humidity observations (HadCRUH). The data sets agree well for both temperature and humidity variations for periods and places of overlap, although the average warming over land is larger for the fully sampled ERA data than for the spatially and temporally incomplete CRUTEM3 data. Near-surface specific humidity varies similarly over land and sea, suggesting that the recent reduction in relative humidity over land may be due to limited moisture supply from the oceans, where evaporation has been limited by sea surface temperatures that have not risen in concert with temperatures over land. Continental precipitation from the reanalyses is compared with a new gauge-based Global Precipitation Climatology Centre (GPCC) data set, with the combined gauge and satellite products of the Global Precipitation Climatology Project (GPCP) and the Climate Prediction Center (CPC), Merged Analysis of Precipitation (CMAP), and with CPC's independent gauge analysis of precipitation over land (PREC/L). The reanalyses agree best with the new GPCC and latest GPCP data sets, with ERA-Interim significantly better than ERA-40 at capturing monthly variability. Shifts over time in the differences among the precipitation data sets make it difficult to assess their longer-term variations and any link with longer-term variations in humidity.

  10. Energetic particle precipitation in ECHAM5/MESSy1 – Part 1: Downward transport of upper atmospheric NOx produced by low energy electrons

    Directory of Open Access Journals (Sweden)

    C. Brühl

    2008-12-01

    Full Text Available The atmospheric chemistry general circulation model ECHAM5/MESSy1 has been extended by processes that parameterize particle precipitation. Several types of particle precipitation that directly affect NOy and HOx concentrations in the middle atmosphere are accounted for and discussed in a series of papers. In the companion paper, the ECHAM5/MESSy1 solar proton event parameterization is discussed, while in the current paper we focus on low energy electrons (LEE that produce NOx in the upper atmosphere. For the flux of LEE NOx into the top of the model domain a novel technique which can be applied to most atmospheric chemistry general circulation models has been developed and is presented here. The technique is particularly useful for models with an upper boundary between the stratopause and mesopause and therefore cannot directly incorporate upper atmospheric NOx production. The additional NOx source parametrization is based on a measure of geomagnetic activity, the Ap index, which has been shown to be a good proxy for LEE NOx interannual variations. HALOE measurements of LEE NOx that has been transported into the stratosphere are used to develop a scaling function which yields a flux of NOx that is applied to the model top. We describe the implementation of the parameterization as the submodel SPACENOX in ECHAM5/MESSy1 and discuss the results from test simulations. The NOx enhancements and associated effects on ozone are shown to be in good agreement with independent measurements. Ap index data is available for almost one century, thus the parameterization is suitable for simulations of the recent climate.

  11. CalWater Field Studies Designed to Quantify the Roles of Atmospheric Rivers and Aerosols in Modulating U.S. West Coast Precipitation in a Changing Climate

    Energy Technology Data Exchange (ETDEWEB)

    Ralph, F. M.; Prather, Kimberly A.; Cayan, Dan; Spackman, J. R.; DeMott, Paul J.; Dettinger, M.; Fairall, C.; Leung, Lai-Yung R.; Rosenfeld, Daniel; Rutledge, Steven A.; Waliser, D.; White, A. B.; Cordeira, J.; Martin, A.; Helly, J.; Intrieri, J.

    2016-08-22

    The variability of precipitation and water supply along the U.S. West Coast creates major challenges to the region’s economy and environment, as evidenced by the recent California drought. This variability is strongly influenced by atmospheric rivers (AR), which deliver much of the precipitation along the U.S. West Coast and can cause flooding, and by aerosols (from local sources and transported from remote continents and oceans) that modulate clouds and precipitation. A better understanding of these processes is needed to reduce uncertainties in weather predictions and climate projections of droughts and floods, both now and under changing climate conditions.To address these gaps a group of meteorologists, hydrologists, climate scientists, atmospheric chemists, and oceanographers have created an interdisciplinary research effort, with support from multiple agencies. From 2009-2011 a series of field campaigns (CalWater 1) collected atmospheric chemistry, cloud microphysics and meteorological measurements in California and associated modeling and diagnostic studies were carried out. Based on remaining gaps, a vision was developed to extend these studies offshore over the Eastern North Pacific and to enhance land based measurements from 2014-2018 (CalWater 2). The data set and selected results from CalWater 1 are summarized here. The goals of CalWater-2, and measurements to date, are then described. CalWater is producing new findings and exploring new technologies to evaluate and improve global climate models and their regional performance and to develop tools supporting water and hydropower management. These advances also have potential to enhance hazard mitigation by improving near-term weather prediction and subseasonal and seasonal outlooks.

  12. Instructional guidelines on sampling of water, atmospheric precipitations, sewage and other liquids, their packing, marking, transportation, preparation to investigations and storage

    International Nuclear Information System (INIS)

    Instructional guidelines was elaborated in the frame of International Scientific Technic Centre project T-1082.3 and directed on arrangement of radiation environment investigations on the territory of the Republic waste disposal site. Instructional guidelines put requirements on sampling of water, atmospheric precipitations, sewage and other liquids, their packing, marking, transportation, preparation of samples to investigation and storage of samples in laboratory conditions. The aim of investigations is revelation of polluted objects on the territory of the Republic waste disposal site, determination of pollution intensity level, pollution dynamics, determination of pollution impact and elaboration measures in order to eliminate their harmful effect on human body and environment.

  13. Long-term precipitation forecast for drought relief using atmospheric circulation factors: a study on the Maharloo Basin in Iran

    Science.gov (United States)

    Sigaroodi, S. K.; Chen, Q.; Ebrahimi, S.; Nazari, A.; Choobin, B.

    2014-05-01

    Long-term precipitation forecasts can help to reduce drought risk through proper management of water resources. This study took the saline Maharloo Lake, which is located in the north of Persian Gulf, southern Iran, and is continuously suffering from drought disaster, as a case to investigate the relationships between climatic indices and precipitation. Cross-correlation in combination with stepwise regression technique was used to determine the best variables among 40 indices and identify the proper time lag between dependent and independent variables for each month. The monthly precipitation was predicted using an artificial neural network (ANN) and multi-regression stepwise methods, and results were compared with observed rainfall data. Initial findings indicated that climate indices such as NAO (North Atlantic Oscillation), PNA (Pacific North America) and El Niño are the main indices to forecast drought in the study area. According to R2, root mean square error (RMSE) and Nash-Sutcliffe efficiency, the ANN model performed better than the multi-regression model, which was also confirmed by classification results. Moreover, the model accuracy to forecast the rare rainfall events in dry months (June to October) was higher than the other months. From the findings it can be concluded that there is a relationship between monthly precipitation anomalies and climatic indices in the previous 10 months in Maharloo Basin. The highest and lowest accuracy of the ANN model were in September and March, respectively. However, these results are subject to some uncertainty due to a coarse data set and high system complexity. Therefore, more research is necessary to further elucidate the relationship between climatic indices and precipitation for drought relief. In this regard, consideration of other climatic and physiographic factors (e.g., wind and physiography) can be helpful.

  14. Interannual variability of a precipitation gradient along the semi-arid catchment areas for the metropolitan region of Lima- Peru in relation to atmospheric circulation at the mesoscale

    Science.gov (United States)

    Otto, Marco; Seidel, Jochen; Trachte, Katja

    2013-04-01

    following questions. How is the interannual variability of the observed precipitation gradient related to atmospheric circulation east (Amazon basin) and west (south-east Pacific) of the study region? If those relations are quantifiable, are there any forecast potentials for the characteristics of the precipitation gradient during the raining season? The results of the study provide valuable information needed to understand the generation of rainfall in the frame of a case study for the largest metropolitan area that is located at the arid Pacific coast of Peru. This information may also be useful for local managers in order to optimise water resource management and land use strategies.

  15. The influence of the limestone-quarry Čertovy schody on the precipitation chemistry and atmospheric deposition

    Czech Academy of Sciences Publication Activity Database

    Špičková, Jitka; Dobešová, Irena; Vach, Marek; Skřivan, Petr; Burian, Miloš

    Prague: Ministry of the Environment CR ; Czech Hydrometeorological Institute; Charles University Environment Center; Czech Geological Survey, 2005 - (Hůnová, I.). s. 132-132 ISBN 80-86690-25-3. [ Acid Rain 2005. International Conference on Acid Deposition /7./. 12.06.2005-17.06.2005, Prague] R&D Projects: GA ČR(CZ) GA205/04/0060 Institutional research plan: CEZ:AV0Z30130516 Keywords : precipitation chemistry * Bohemian Karst * trace metals Subject RIV: DD - Geochemistry

  16. Historical changes and future projections of precipitation and its extremes in the 20th and 21st century simulation by a 60-km mesh global atmospheric model

    Science.gov (United States)

    Kitoh, A.; Kamiguchi, K.; Arakawa, O.; Kusunoki, S.

    2010-12-01

    Climate of the 20th century simulation was conducted with a 60-km mesh global atmospheric model (MRI-AM60km) from year 1872 to the present, forced with observed historical sea surface temperature and sea ice (HadISST1). Time variations of global and hemisphere average land surface air temperatures are reasonably well simulated in the 20th century. The number of simulated tropical cyclone in the whole globe has decreasing trend throughout the 20th century. Precipitation of the Monsoon Asia region is evaluated against the newly created daily gridded precipitation data set (APHRODITE), which improves topographic features in mountainous regions. The observed data set indicates a delay of the East Asian early summer rainy season (Baiu) in recent decades. The MRI-AM60km well reproduces this feature, but also shows multi-decadal variability. The same model is used for the future climate projections throughout the 21st century. Changes in mountainous precipitaion as well as extreme precipitation are also investigated.

  17. Ground-Based Cloud and Atmospheric Boundary Layer Observations for the Project: High Definition Clouds and Precipitation for Advancing Climate Prediction, HD(CP)2

    Science.gov (United States)

    Hirsikko, A.; Ebell, K.; Ulrich, U.; Schween, J. H.; Bohn, B.; Görsdorf, U.; Leinweber, R.; Päschke, E.; Baars, H.; Seifert, P.; Klein Baltink, H.

    2014-12-01

    The German research initiative ''High Definition Clouds and Precipitation for advancing Climate Prediction, HD(CP)2'' aims for an improved representation of clouds and precipitation in climate models. Model development and its evaluation require comprehensive observational datasets. A specific work package was established to create uniform and documented observational datasets for the HD(CP)2 data base. Datasets included ground-based remote-sensing (Doppler lidars, ceilometers, microwave radiometers, and cloud radars) and in-situ (meteorological and radiation sensors) measurements. Four supersites (Jülich ObservatorY for Cloud Evolution (JOYCE), Lindenberg Meteorological Observatory - Richard Assmann Observatory (RAO), and Leipzig Aerosol and Cloud Remote Observations System (LACROS) in Germany, and Cabauw experimental site for atmospheric research (Cesar) in the Netherlands) are finalizing the operational procedures to provide quality controlled (and calibrated if possible) remote-sensing and in-situ observations, retrievals on atmospheric boundary layer state (e.g. winds, mixing layer height, humidity and temperature), and cloud macro and micro physical properties with uncertainty estimations or at least quality flags. During the project new processing and retrieval methods were developed if no commonly agreed or satisfying methods were available. Especially, large progress was made concerning uncertainty estimation and automated quality control. Additionally, the data from JOYCE are used in a radiative closure studies under cloudy conditions to evaluate retrievals of cloud properties. The current status of work progress will be presented.

  18. Precipitation rates and atmospheric heat transport during the Cenomanian greenhouse warming in North America: Estimates from a stable isotope mass-balance model

    Science.gov (United States)

    Ufnar, David F.; Ludvigson, Greg A.; Gonzalez, L.; Grocke, D.R.

    2008-01-01

    correlate with a mean annual average heat loss of 48??W/m2 at 10??N paleolatitude (present, 8??W/m2 at 15??N). The increased precipitation flux and moisture surplus in the mid-latitudes corresponds to a mean average annual heat gain of 180??W/m2 at 50??N paleolatitude (present, 17??W/m2 at 50??N). The Cenomanian low-latitude moisture deficit is similar to that of the Albian, however the mid-latitude (40-60??N) precipitation flux values and precipitation rates are significantly higher (Albian: 2200??mm/yr at 45??N; Cenomanian: 3600??mm/yr at 45??N). Furthermore, the heat transferred to the atmosphere via latent heat of condensation was approximately 10.6?? that of the present at 50??N. The intensified hydrologic cycle of the mid-Cretaceous greenhouse warming may have played a significant role in the poleward transfer of heat and more equable global conditions. Paleoclimatological reconstructions from multiple time periods during the mid-Cretaceous will aid in a better understanding of the dynamics of the hydrologic cycle and latent heat flux during greenhouse world conditions.

  19. Multi-scale analysis of the impact of increased spatial resolution of soil moisture and atmospheric water vapour on convective precipitation

    Science.gov (United States)

    Khodayar, S.; Schaedler, G.; Kalthoff, N.

    2010-09-01

    The distribution of water vapour in the planetary boundary layer (PBL) and its development over time is one of the most important factors affecting precipitation processes. Despite the dense radiosonde network deployed during the Convective and Orographically-induced Precipitation Study (COPS), the high spatial variability of the water vapour field was not well resolved with respect to the detection of the initiation of convection. The first part of this investigation focuses on the impact of an increased resolution of the thermodynamics and dynamics of the PBL on the detection of the initiation of convection. The high spatial resolution was obtained using the synergy effect of data from the networks of radiosondes, automatic weather stations, synoptic stations, and especially Global Positioning Systems (GPSs). A method is introduced to combine GPS and radiosonde data to obtain a higher resolution representation of atmospheric water vapour. The gained spatial resolution successfully improved the representations of the areas where deep convection likelihood was high. Location and timing of the initiation of convection were critically influenced by the structure of the humidity field in the boundary-layer. The availability of moisture for precipitation is controlled by a number of processes including land surface processes, the latter are strongly influenced by spatially variable fields of soil moisture (SM) and land use. Therefore, an improved representation of both fields in regional model systems can be expected to produce better agreement between modelled and measured surface energy fluxes, boundary layer structure and precipitation. SM is currently one of the least assessed quantities with almost no data from operational monitoring networks available. However, during COPS an innovative measurement approach using a very high number of different SM sensors was introduced. The network consisted of newly developed low-cost SM sensors installed at 43 stations. Each

  20. Midwestern streamflow, precipitation, and atmospheric vorticity influenced by Pacific sea-surface temperatures and total solar-irradiance variations

    Science.gov (United States)

    Perry, C.A.

    2006-01-01

    A solar effect on streamflow in the Midwestern United States is described and supported in a six-step physical connection between total solar irradiance (TSI), tropical sea-surface temperatures (SSTs), extratropical SSTs, jet-stream vorticity, surface-layer vorticity, precipitation, and streamflow. Variations in the correlations among the individual steps indicate that the solar/hydroclimatic mechanism is complex and has a time element (lag) that may not be constant. Correct phasing, supported by consistent spectral peaks between 0.092 and 0.096 cycles per year in all data sets within the mechanism is strong evidence for its existence. A significant correlation exists between total solar irradiance and the 3-year moving average of annual streamflow for Iowa (R = 0.67) and for the Mississippi River at St Louis, Missouri (R = 0.60), during the period 1950-2000. Published in 2005 by John Wiley & Sons, Ltd.

  1. Hourly Precipitation Data (HPD) Publication

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hourly Precipitation Data (HPD) Publication is archived and available from the National Climatic Data Center (NCDC). This publication contains hourly precipitation...

  2. Use of Total Precipitable Water Classification of A Priori Error and Quality Control in Atmospheric Temperature and Water Vapor Sounding Retrieval

    Institute of Scientific and Technical Information of China (English)

    Eun-Han KWON; Jun LI; Jinlong LI; B. J. SOHN; Elisabeth WEISZ

    2012-01-01

    This study investigates the use of dynamic a priori error information according to atmospheric moistness and the use of quality controls in temperature and water vapor profile retrievals from hyperspectral infrared (IR) sounders.Temperature and water vapor profiles are retrieved from Atmospheric InfraRed Sounder (AIRS) radiance measurements by applying a physical iterative method using regression retrieval as the first guess. Based on the dependency of first-guess errors on the degree of atmospheric moistness,the a priori first-guess errors classified by total precipitable water (TPW) are applied in the AIRS physical retrieval procedure.Compared to the retrieval results from a fixed a priori error,boundary layer moisture retrievals appear to be improved via TPW classification of a priori first-guess errors.Six quality control (QC)tests,which check non-converged or bad retrievals,large residuals,high terrain and desert areas,and large temperature and moisture deviations from the first guess regression retrieval,are also applied in the AIRS physical retrievals.Significantly large errors are found for the retrievals rejected by these six QCs,and the retrieval errors are substantially reduced via QC over land,which suggest the usefulness and high impact of the QCs,especially over land.In conclusion,the use of dynamic a priori error information according to atmospheric moistness,and the use of appropriate QCs dealing with the geographical information and the deviation from the first-guess as well as the conventional inverse performance are suggested to improve temperature and moisture retrievals and their applications.

  3. Coupled atmosphere ocean climate model simulations in the Mediterranean region: effect of a high-resolution marine model on cyclones and precipitation

    Directory of Open Access Journals (Sweden)

    A. Sanna

    2013-06-01

    Full Text Available In this study we investigate the importance of an eddy-permitting Mediterranean Sea circulation model on the simulation of atmospheric cyclones and precipitation in a climate model. This is done by analyzing results of two fully coupled GCM (general circulation models simulations, differing only for the presence/absence of an interactive marine module, at very high-resolution (~ 1/16°, for the simulation of the 3-D circulation of the Mediterranean Sea. Cyclones are tracked by applying an objective Lagrangian algorithm to the MSLP (mean sea level pressure field. On annual basis, we find a statistically significant difference in vast cyclogenesis regions (northern Adriatic, Sirte Gulf, Aegean Sea and southern Turkey and in lifetime, giving evidence of the effect of both land–sea contrast and surface heat flux intensity and spatial distribution on cyclone characteristics. Moreover, annual mean convective precipitation changes significantly in the two model climatologies as a consequence of differences in both air–sea interaction strength and frequency of cyclogenesis in the two analyzed simulations.

  4. Temporal complexity of daily precipitation records from different atmospheric environments: Chaotic and Lévy stable parameters

    Science.gov (United States)

    Millán, H.; Rodríguez, J.; Ghanbarian-Alavijeh, B.; Biondi, R.; Llerena, G.

    2011-09-01

    Rainfall events are very erratic at short and large temporal and spatial scales. The main objectives of the present study were (i) to describe different time series of daily precipitation records using both chaos theory and stable distribution methods and (ii) to search for potential relationships between chaotic and Lévy-stable parameters. We studied eight time series of daily rainfall from different latitudes around the world. Each rainfall signal spanned nine years (1997-2005). We used methods derived from chaos theory (embedding delays, spectrum of Lyapunov exponents, determinism tests and others) and parameters computed after fitting a stable distribution model to each differenced time series of rainfall data. All the rainfall signals showed chaotic structures with two positive Lyapunov exponents. The stability index was α < 2 which accounts for the scale-free behavior of rainfall dynamics. There were found latent statistical relationships between chaotic and Lévy stable parameters. That represents a potential connection between chaotic behavior, sub-Gaussian statistics and rainfall dynamics. Future research should deal with the connection between chaotic invariants, stable parameters and rainfall phenomenology.

  5. Storage Gage Precipitation Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A storage gage is a precipitation gage that requires reading and maintenance only monthly or seasonal intervals. This library includes reports from such gages,...

  6. WPA Precipitation Tabulations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hourly precipitation data tabulated under the Work Projects Administration (WPA), a New Deal program created to reduce unemployment during the Great Depression....

  7. The impact of data assimilation of ground-based GPS precipitable water vapor to numerical weather prediction model on estimation of ray-traced atmospheric slant delays

    Science.gov (United States)

    Ichikawa, R.; Hobiger, T.; Shoji, Y.; Miyauchi, Y.

    2012-12-01

    The ''KAshima RAytracing Tools (KARAT)'' is capable of calculating total slant delays and ray-bending angles considering real atmospheric phenomena. One advantage of KARAT is that the reduction of atmospheric path delay will become more accurate each time the numerical weather model is improved. On October 27, 2009 the JMA started data assimilation of zenith wet delays obtained by the GPS Earth Observation Network System (GEONET) operated by Geospatial Information Authority of Japan (GSI) for meso-scale NWP model. The improved NWP model data assimilating the GPS PWV data has the potential to correct the atmospheric path delay more precisely. Meteorological Research Institute (MRI) of Japan has evaluated the impact of ground-based GPS precipitable water vapor (GPS PWV) derived from the GEONET on meso-scale NWP model under the localized heavy rainfall event in Tokyo, Japan on 5 August 2008. A terrific thunderstorm occurred across the Kanto area of Japan, and it caused flooding in downtown Tokyo. During the event, the rainfall intensity increased to over 100 mm per hour within thirty minutes. We have assessed the impacts of GPS PWV assimilation into the NWP model on the KARAT correction by comparisons of the precise point positioning (PPP) solutions. In the nationwide scale of Japan, the short time repeatability of the PPP results for both horizontal and height positions applying KARAT correction through the MRI NWP model with GPS PWV assimilation are about several percent better than that through the conventional MRI NPW model w/o GPS PWV assimilation. In addition we are now investigating the impact of GPS PWV data assimilation in more detail. We will present the updated results of the comparison study.

  8. Study of total column atmospheric aerosol optical depth, ozone and precipitable water content over Bay of Bengal during BOBMEX-99

    Indian Academy of Sciences (India)

    K K Dani; R S Maheskumar; P C S Devara

    2003-06-01

    The spatial and temporal variations in aerosols and precursor gases over oceanic regions have special importance in the estimation of radiative forcing parameters and thereby in the refinement of general circulation models. Extensive observations of the columnar aerosol optical depth (AOD), total column ozone (TCO) and precipitable water content (PWC) have been carried out using the on-line, multi-band solar radiometers onboard ORV Sagar Kanya (Cruise#SK 147B) over Bay of Bengal during 11th-28th August 1999. Aerosol optical and physical properties (optical depth and angstrom parameter) have been estimated at six wavelengths covering from UV to NIR (380-1020 nm) while TCO and PWC have been determined using the UV band around 300nm and NIR band around 940 nm, respectively. Added, concurrent meteorological and satellite observations during this field phase of BOBMEX-99 have been utilized to investigate spectral-temporal variations of AOD, TCO and PWC in marine environment. The results indicate lower AODs (around 0.4 at characteristic wavelength of 500 nm) and size distributions with abundance of coarse-mode particles as compared to those aerosols of typical land origin. An interesting result that is found in the present study is the significant reduction in AOD at all wavelengths from initial to later part of observation period due to cloud-scavenging and rain-washout effects as well as signature of coastal aerosol loading. The clear-sky daytime diurnal variation of TCO shows gradual increase during post-sunrise hours, broad maximum during afternoon hours and gradual decrease during pre-sunset hours, which is considered to be due to photochemical reactions. The diurnal variation curve of PWC showed maximum (∼4cm) during morning hours and gradual decrease (∼3.5cm) towards evening hours, which are found to be greater as compared to typical values over land. Another interesting feature observed is that although the PWC values are very high, there was no proportionate

  9. Atmosphere

    Science.gov (United States)

    Ghosh, D.; Mitra, S. K.

    2014-05-01

    This paper investigates the high-temperature corrosion behavior of microstructurally different regions of the weldment of 9 Cr-1 Mo steel used in thermal power plant boiler in SO2 + O2 environment. The weldment is produced by tungsten inert gas welding method, and the different regions of the weldment (weld metal, heat-affected zone, and base metal) are exposed in SO2 + O2 (ratio 2:1) environment at 973 K for 120 h. The reaction kinetics and corrosion growth rate of different regions of weldment in isothermal condition are evaluated. The post corroded scales of the different specimens are studied in SEM, EDS, and XRD. The results indicate that the weld metal shows higher corrosion rate followed by HAZ and base metal. The higher rate of corrosion of weldmetal is mainly attributed to the least protective inner scale of Cr2O3 with minimum Cr Content. This is due to the formation of delta ferrite, which leads to the precipitation of the Cr-based secondary phases and depletes the free Cr from the matrix. The thermal cycles during welding at high temperature are favorable for the formation of delta ferrite. On the other hand, in absence of delta ferrite, the base metal and HAZ regions of the weldment show lower corrosion rate than weld metal. The difference in corrosion rate in the three regions of the weldment is supplemented by post-corroded scale characterizations.

  10. The magnetic and oxidation behavior of bare and silica-coated iron oxide nanoparticles synthesized by reverse co-precipitation of ferrous ion (Fe2+) in ambient atmosphere

    International Nuclear Information System (INIS)

    The synthesis of iron oxide nanoparticles, i.e., magnetite was attempted by using only ferrous ion (Fe2+) as a magnetite precursor, under an ambient atmosphere. The room temperature reverse co-precipitation method was used, by applying two synthesis protocols. The freshly prepared iron oxide was also immediately coated with Stöber silica (SiO2) layer, forming the coreshell structure. The phase, stoichiometry, crystallite and the particle size of the synthesized powders were determined by using X-ray diffraction (XRD) and transmission electron microscope (TEM), while the magnetic and oxidation behaviors were studied by using the vibrating sample magnetometer (VSM) and Mössbauer spectroscopy. Based on the results, the bare iron oxide nanoparticles are in the stoichiometry between the magnetite and the maghemite stoichiometry, i.e., oxidation occurs. This oxidation is depending on the synthesis protocols used. With the silica coating, the oxidation can be prevented, as suggested by the fits of Mössbauer spectra and low temperature magnetic measurement. - Highlights: • Synthesis of magnetite was attempted by using ferrous ion (Fe2+) in air. • The synthesized particle has a stoichiometry in between magnetite and maghemite. • Silica shell partly prevented the oxidation as suggested by magnetic and Mössbauer study

  11. Variability in warm-season atmospheric circulation and precipitation patterns over subtropical South America: relationships between the South Atlantic convergence zone and large-scale organized convection over the La Plata basin

    Science.gov (United States)

    Mattingly, Kyle S.; Mote, Thomas L.

    2016-03-01

    Warm-season precipitation variability over subtropical South America is characterized by an inverse relationship between the South Atlantic convergence zone (SACZ) and precipitation over the central and western La Plata basin of southeastern South America. This study extends the analysis of this "South American Seesaw" precipitation dipole to relationships between the SACZ and large, long-lived mesoscale convective systems (LLCSs) over the La Plata basin. By classifying SACZ events into distinct continental and oceanic categories and building a logistic regression model that relates LLCS activity across the region to continental and oceanic SACZ precipitation, a detailed account of spatial variability in the out-of-phase coupling between the SACZ and large-scale organized convection over the La Plata basin is provided. Enhanced precipitation in the continental SACZ is found to result in increased LLCS activity over northern, northeastern, and western sections of the La Plata basin, in association with poleward atmospheric moisture flux from the Amazon basin toward these regions, and a decrease in the probability of LLCS occurrence over the southeastern La Plata basin. Increased oceanic SACZ precipitation, however, was strongly related to reduced atmospheric moisture and decreased probability of LLCS occurrence over nearly the entire La Plata basin. These results suggest that continental SACZ activity and large-scale organized convection over the northern and eastern sections of the La Plata basin are closely tied to atmospheric moisture transport from the Amazon basin, while the warm coastal Brazil Current may also play an important role as an evaporative moisture source for LLCSs over the central and western La Plata basin.

  12. Future changes and uncertainties in Asian precipitation simulated by multiphysics and multi-sea surface temperature ensemble experiments with high-resolution Meteorological Research Institute atmospheric general circulation models (MRI-AGCMs)

    Science.gov (United States)

    Endo, Hirokazu; Kitoh, Akio; Ose, Tomoaki; Mizuta, Ryo; Kusunoki, Shoji

    2012-08-01

    This study focuses on projecting future changes in mean and extreme precipitation in Asia, and discusses their uncertainties. Time-slice experiments using a 20-km-mesh atmospheric general circulation (AGCM) were performed both in the present-day (1979-2003) and the future (2075-2099). To assess the uncertainty of the projections, 12 ensemble projections (i.e., combination of 3 different cumulus schemes and 4 different sea surface temperature (SST) change patterns) were conducted using 60-km-mesh AGCMs. For the present-day simulations, the models successfully reproduced the pattern and amount of mean and extreme precipitation, although the model with the Arakawa-Schubert (AS) cumulus scheme underestimated the amount of extreme precipitation. For the future climate simulations, in South Asia and Southeast Asia, mean and extreme precipitation generally increase, but their changes show marked differences among the projections, suggesting some uncertainty in their changes over these regions. In East Asia, northwestern China and Bangladesh, in contrast, mean and extreme precipitation show consistent increases among the projections, suggesting their increases are reliable for this model framework. Further investigation by analysis of variance (ANOVA) revealed that the uncertainty in the precipitation changes in South Asia and Southeast Asia are derived mainly from differences in the cumulus schemes, with an exception in the Maritime Continent where the uncertainty originates mainly from the differences in the SST pattern.

  13. Air mass patterns and temporal variation of the isotopic composition of atmospheric water vapour and precipitation over central Turkey and groundwater recharge

    International Nuclear Information System (INIS)

    Water vapour and event precipitation have been collected within the program of coordinated research project about isotopic composition of precipitation in the Mediterranean basin in relation to air circulation patterns and climate at Ankara since January 2001. The purpose of this study is the determination of the interaction between climate conditions, chemical composition and isotopic composition (oxygen 18 and deuterium) of precipitation and water vapor in Turkey. For this purpose we have been collecting samples at Ankara station to understand the variation of daily/event and seasonal isotopic values of precipitation and water vapor. The study focuses on the systematic collection of basic data on isotope content of precipitation and water vapor in Ankara, Turkey to determine temporal variations of environmental isotopes in precipitation and consequently to provide basic isotopic data for the use of environmental isotopes in hydrological investigations within the scope of water resources inventory, planning and development

  14. U.S. 15 Minute Precipitation Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — U.S. 15 Minute Precipitation Data is digital data set DSI-3260, archived at the National Climatic Data Center (NCDC). This is precipitation data. The primary source...

  15. Precipitation Reconstruction (PREC)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The PREC data set is an analysis of monthly precipitation constructed on a 2.5(o)lat/lon grid over the global for the period from 1948 to the present. The land...

  16. Hourly and Daily Precipitation Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Precipitation reports submitted on many form types, including tabular and autographic charts. Reports are almost exclusively from the US Cooperative Observer Network.

  17. Climate Prediction Center (CPC) Global Precipitation Time Series

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The global precipitation time series provides time series charts showing observations of daily precipitation as well as accumulated precipitation compared to normal...

  18. Numerical simulation of heavy precipitation events using mesoscale weather forecast models. Validation with radar data and diagnosis of the atmospheric moisture budget; Numerische Simulation von Starkniederschlagsereignissen mit mesoskaligen Wettervorhersagemodellen. Ueberpruefung mit Radar-Daten und Diagnose der atmosphaerischen Wasserbilanz

    Energy Technology Data Exchange (ETDEWEB)

    Keil, C.

    2000-07-01

    Convective precipitation systems contribute substantially to the summertime rainfall maximum in the northern Alpine region. The capability of mesoscale weather forecast models in capturing such heavy precipitation events is investigated. The complementary application of so far hardly used areal radar data and conventional rain gauge observations enables a case-study-type evaluation of summertime precipitation episodes. Different rainfall episodes are simulated with the former operational model (DM, meshsize 14 km) of Deutscher Wetterdienst (DWD). The influence of the horizontal resolution and the parameterization of moist convection is subsequently studied with a higher resolution atmospheric model (MC2, meshsize 2 km). Diagnostic studies on the atmospheric water budget regarding the rainfall episode, which instigated the Oder-flood in summer 1997, allow an examination of the origin of the moisture and the genesis of the copious precipitation. (orig.) [German] Konvektive Niederschlagssysterne tragen im Nordalpenraum wesentlich zum sommerlichen Niederschlagsmaximum bei. Die Faehigkeit mesoskaliger Wettervorhersagemodelle, solche Starkniederschlagsereignisse zu erfassen, wird in dieser Arbeit untersucht. Durch den komplementaeren Gebrauch von, bisher kaum genutzten, flaechendeckenden Radardaten und konventionellen Niederschlagsmessungen des Bodenmessnetzes werden Modellergebnisse sommerlicher Niederschlagssysteme fallstudienhaft detailliert ueberprueft. Fuer verschiedene Starkniederschlagsereignisse werden dazu Modellsimulationen mit dem in den 90er Jahren operationellen Modell (DM, Maschenweite 14 km) des Deutschen Wetterdienstes (DWD) durchgefuehrt. Zur Untersuchung des Einflusses der horizontalen Maschenweite und der Niederschlagsparametrisierung werden ferner numerische Simulationen mit einem hoeher aufloesdenden Atmosphaerenmodell (MC2, Maschenweite 2 km) behandelt. Anhand diagnostischer Untersuchungen der atmosphaerischen Wasserbilanz laesst sich ausserdem die

  19. Air mass patterns and temporal variation of the isotopic composition of atmospheric water vapour and precipitation over Central Turkey and groundwater recharge

    International Nuclear Information System (INIS)

    Full text: Water vapour and event precipitation have been collected within the program of coordinated research project about isotopic composition of precipitation in the Mediterranean basin in relation to air circulation patterns and climate at Ankara since January 2001. The purpose of this study is the determination of the interaction between climate conditions, chemical composition and isotopic composition (δ18O, δ2H) of precipitation and water vapor in Turkey. For this purpose we have been collecting samples at Ankara station to understand the variation of daily/event and seasonal isotopic values of precipitation and water vapor. The study focuses on the systematic collection of basic data on isotope content of precipitation and water vapor in Ankara, Turkey to determine temporal variations of environmental isotopes in precipitation and consequently to provide basic isotopic data for the use of environmental isotopes in hydrological investigations within the scope of water resources inventory, planning and development. Sampling of rain water and water vapor have been carried out in Ankara Turkey, from January 2001 to December 2001, by means of a pluviometer, water vapor sampling system respectively. The relation between the isotopic composition of precipitation and synoptic parameters is examined. The rain samples can be separated into three group based on 'deuterium excess' for year 2001 and long term observation of Ankara, Antalya and Adana stations of Turkey. The majority of the samples have a 'deuterium excess' between 10 and 22 per mille and other has values less than 10 per mille and greater than 22. The rains with a 'deuterium excess' of more than 22 per mille, between 10 and 22 and less than 10 are associated with air masses which comes from East Mediterranean (SW), North Atlantic (N, NW) and Central Atlantic (W, SW) respectively. Although it is not possible to derive the isotopic composition of the water vapor from isotopic composition of

  20. Composition Changes After the "Halloween" Solar Proton Event: The High-Energy Particle Precipitation in the Atmosphere (HEPPA) Model Versus MIPAS Data Intercomparison Study

    Science.gov (United States)

    Funke, B.; Baumgaertner, A.; Calisto, M.; Egorova, T.; Jackman, C. H.; Kieser, J.; Krivolutsky, A.; Lopez-Puertas, M.; Marsh. D. R.; Reddmann, T.; Rozanov, E.; Salmi, S.-M.; Sinnhuber, M.; Stiller, G. P.; Verronen, P. T.; Versick, S.; vonClarmann, T.; Vyushkova, T. Y.; Wieters, N.; Wissing, J. M.

    2010-01-01

    We have compared composition changes of NO, NO2, H2O2,O3, N2O, HNO3 , N2O5, HNO4, ClO, HOCl, and ClONO2 as observed by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on Envisat in the aftermath of the "Halloween" solar proton event (SPE) in October/November 2003 at 25-0.01 hPa in the Northern hemisphere (40-90 N) and simulations performed by the following atmospheric models: the Bremen 2D model (B2dM) and Bremen 3D Chemical Transport Model (B3dCTM), the Central Aerological Observatory (CAO) model, FinROSE, the Hamburg Model of the Neutral and Ionized Atmosphere (HAMMONIA), the Karlsruhe Simulation Model of the Middle Atmosphere (KASIMA), the ECHAM5/MESSY Atmospheric Chemistry (EMAC) model, the modeling tool for SO1ar Climate Ozone Links studies (SOCOL and SOCOLi), and the Whole Atmosphere Community Climate Model (WACCM4). The large number of participating models allowed for an evaluation of the overall ability of atmospheric models to reproduce observed atmospheric perturbations generated by SPEs, particularly with respect to NOS, and ozone changes. We have further assessed the meteorological conditions and their implications on the chemical response to the SPE in both the models and observations by comparing temperature and tracer (CH4 and CO) fields. Simulated SPE-induced ozone losses agree on average within 5% with the observations. Simulated NO(y) enhancements around 1 hPa, however, are typically 30% higher than indicated by the observations which can be partly attributed to an overestimation of simulated electron-induced ionization. The analysis of the observed and modeled NO(y) partitioning in the aftermath of the SPE has demonstrated the need to implement additional ion chemistry (HNO3 formation via ion-ion recombination and water cluster ions) into the chemical schemes. An overestimation of observed H2O2 enhancements by all models hints at an underestimation of the OH/HO2 ratio in the upper polar stratosphere during the SPE. The

  1. ROE Precipitation

    Data.gov (United States)

    U.S. Environmental Protection Agency — This polygon dataset represents the rate of change in precipitation across the United States in terms of percent change per century. The map shows National Oceanic...

  2. Acid Precipitation and the Forest Ecosystem

    Science.gov (United States)

    Dochinger, Leon S.; Seliga, Thomas A.

    1975-01-01

    The First International Symposium on Acid Precipitation and the Forest Ecosystem dealt with the potential magnitude of the global effects of acid precipitation on aquatic ecosystems, forest soils, and forest vegetation. The problem is discussed in the light of atmospheric chemistry, transport, and precipitation. (Author/BT)

  3. Future summer precipitation changes over CORDEX-East Asia domain downscaled by a regional ocean-atmosphere coupled model: A comparison to the stand-alone RCM

    Science.gov (United States)

    Zou, Liwei; Zhou, Tianjun

    2016-03-01

    Climate changes under the RCP8.5 scenario over the Coordinated Regional Downscaling Experiment (CORDEX)-East Asia domain downscaled by a regional ocean-atmosphere coupled model Flexible Regional Ocean-Atmosphere Land System (FROALS) are compared to those downscaled by the corresponding atmosphere-only regional climate model driven by a global climate system model. Changes in the mean and interannual variability of summer rainfall were discussed for the period of 2051-2070 with respect to the present-day period of 1986-2005. Followed by an enhanced western North Pacific subtropical high and an intensified East Asian summer monsoon, an increase in total rainfall over north China, the Korean Peninsula, and Japan but a decrease in total rainfall over southern China are observed in the FROALS projection. Homogeneous increases of extreme rainfall amounts were found over the CORDEX-East Asia domain. A predominant increase in the interannual variability was evident for both total rainfall and the extreme rainfall amount. The spatial patterns of the projected rainfall changes by FROALS were generally consistent with those from the driving global model at a broad scale due to similar projected circulation changes. In both models, the enhanced southerlies over east China increased the moisture divergences over southern China and enhanced the moisture advection over north China. However, the atmosphere-only regional climate model (RCM) exhibited responses to the underlying sea surface temperature (SST) warming anomalies that were too strong, which induced an anomalous cyclone over the north South China Sea, followed by increases (decreases) of total and extreme rainfall over southern China (central China). The differences of the projected changes in both rainfall and circulation between FROALS and the atmosphere-only RCM were partly affected by the differences in the projected SST changes. The results recommend the employment of a regional ocean-atmosphere coupled model in the

  4. Composition changes after the "Halloween" solar proton event: the High Energy Particle Precipitation in the Atmosphere (HEPPA model versus MIPAS data intercomparison study

    Directory of Open Access Journals (Sweden)

    B. Funke

    2011-09-01

    Full Text Available We have compared composition changes of NO, NO2, H2O2, O3, N2O, HNO3, N2O5, HNO4, ClO, HOCl, and ClONO2 as observed by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS on Envisat in the aftermath of the "Halloween" solar proton event (SPE in late October 2003 at 25–0.01 hPa in the Northern Hemisphere (40–90° N and simulations performed by the following atmospheric models: the Bremen 2-D model (B2dM and Bremen 3-D Chemical Transport Model (B3dCTM, the Central Aerological Observatory (CAO model, FinROSE, the Hamburg Model of the Neutral and Ionized Atmosphere (HAMMONIA, the Karlsruhe Simulation Model of the Middle Atmosphere (KASIMA, the ECHAM5/MESSy Atmospheric Chemistry (EMAC model, the modeling tool for SOlar Climate Ozone Links studies (SOCOL and SOCOLi, and the Whole Atmosphere Community Climate Model (WACCM4. The large number of participating models allowed for an evaluation of the overall ability of atmospheric models to reproduce observed atmospheric perturbations generated by SPEs, particularly with respect to NOy and ozone changes. We have further assessed the meteorological conditions and their implications for the chemical response to the SPE in both the models and observations by comparing temperature and tracer (CH4 and CO fields.

    Simulated SPE-induced ozone losses agree on average within 5 % with the observations. Simulated NOy enhancements around 1 hPa, however, are typically 30 % higher than indicated by the observations which are likely to be related to deficiencies in the used ionization rates, though other error sources related to the models' atmospheric background state and/or transport schemes cannot be excluded. The analysis of the observed and modeled NOy partitioning in the aftermath of the SPE has demonstrated the need to implement

  5. Chemornetric Analysis of Atmospheric Precipitation of Xinjiang Karamay%克拉玛依市大气降水化学的统计学分析

    Institute of Scientific and Technical Information of China (English)

    刘欣

    2011-01-01

    运用相关分析、因子分析和聚类分析等统计学分析方法,对2009—2010年新疆克拉玛依市的大气降水化学组成和分布特征进行分析。结果表明,SO4^2-、Cl^-、Ca^2+和Na^+是降水中主要离子。降水的pH值、电导率、降水量和各离子组份均呈现明显的正偏态分布,降水样品以低离子含量的样本为主,因子分析和聚类分析2种分类方法分析降水中水溶性离子主要分为3类。SO4^2-、Cl^-、Mg^2+、F^-主要来自人为活动的贡献,K^+、Ca^2+主要来源于土壤和沙尘等地壳,H^+与其他阴、阳离子间并未表现出明显的相关关系,表明研究区域的降水酸度是所有致酸离子和各种离子综合作用的结果,而不是降水中某个单一的离子组份确定的。%The characteristics and distribution of precipitation chemistry of Karamay in the central region of xinjiang province during 2009 - 2010 was analyzed by statistical methods such as regression analysis, factor analysis and duster analysis to investigate. The results indicated SO4^2- ,Cl^- and Ca^2+ and Na^+ were the major ions in the precipitation. Skewness calculations for pH, EC and all the ions had showed a positive value that indicated a right asymmetric shape of the data distribution. Precipitation samples was low ionic in the sample of mainly, the precipitation of water soluble ion divided mainly into three categories using factor analysis and cluster analysis . SO4^2- , Cl^- ,Mg^2+ . F^- mainly came from human activity, K^+ ,Ca^2+ mainly came from the soil and dust on the earth' s crust. H + with other anion and cation had no distinct correlation. It was indicated that the precipitation' s acidity was all the ions comprehensive role as a result, instead of precipitation in a single set of the components.

  6. Composition changes after the "Halloween" solar proton event: the High-Energy Particle Precipitation in the Atmosphere (HEPPA model versus MIPAS data intercomparison study

    Directory of Open Access Journals (Sweden)

    B. Funke

    2011-03-01

    Full Text Available We have compared composition changes of NO, NO2, H2O2, O3, N2O, HNO3, N2O5, HNO4, ClO, HOCl, and ClONO2 as observed by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS on Envisat in the aftermath of the "Halloween" solar proton event (SPE in October/November 2003 at 25–0.01 hPa in the Northern Hemisphere (40–90° N and simulations performed by the following atmospheric models: the Bremen 2d Model (B2dM and Bremen 3d Chemical Transport Model (B3dCTM, the Central Aerological Observatory (CAO model, FinROSE, the Hamburg Model of the Neutral and Ionized Atmosphere (HAMMONIA, the Karlsruhe Simulation Model of the Middle Atmosphere (KASIMA, the ECHAM5/MESSy Atmospheric Chemistry (EMAC model, the modeling tool for SOlar Climate Ozone Links studies (SOCOL and SOCOLi, and the Whole Atmosphere Community Climate Model (WACCM4. The large number of participating models allowed for an evaluation of the overall ability of atmospheric models to reproduce observed atmospheric perturbations generated by SPEs, particularly with respect to NOy and ozone changes. We have further assessed the meteorological conditions and their implications on the chemical response to the SPE in both the models and observations by comparing temperature and tracer (CH4 and CO fields.

    Simulated SPE-induced ozone losses agree on average within 5% with the observations. Simulated oy enhancements around 1 hPa, however, are typically 30% higher than indicated by the observations which can be partly attributed to an overestimation of simulated electron-induced ionization. The analysis of the observed and modeled NOy partitioning in the aftermath of the SPE has demonstrated the need to implement additional ion chemistry (HNO3 formation via ion-ion recombination and water cluster ions into the chemical

  7. 大气降水重金属含量特征及来源分析%Characteristics and source analysis of heavy metals in atmospheric precipitation of Boyang Lake basin

    Institute of Scientific and Technical Information of China (English)

    胡春华; 柯丽; 童乐; 周文斌

    2012-01-01

    Precipitation samples were collected from 8 cities and counties of Poyang Lake basin during January to December of 2010. Heavy metal ions (Pb, Cu, Zn, Cd, Cr and Fe) in atmospheric precipitation were detected by atomic absorption spectrophotometer to investigate the concentration and distribution characteristics of heavy metals in precipitation of Boyang Lake basin, the contamination source of these heavy metals were also analyzed. The results indicated that the annual mean concentration of Pb, Cu, Zn, Cd, Cr and Fe was 9. 53, 11. 32, 33. 73, 1. 55, 9. 09, 142. 65 μg/L, respectively. Pb, Cu, Cd and Cr were major influenced by human factors, the second and the tertiary industry were the main source of these contamination. Zn and Fe in atmospheric precipitation were little affected by the human being, Zn was mainly from natural source and Fe was originated from mix source.%于2010年1月至12月采集鄱阳湖流域8个县市的大气降水样品,用原子吸收分光光度计测定大气降水中溶解态Pb、Cu、Zn、Cd、Cr、Fe等重金属离子,阐述鄱阳湖流域大气降水中重金属含量及分布特征,并分析各种重金属来源.结果表明,Pb年际平均质量浓度为9.53 μg/L,Cu为11.32 μg/L,Zn为33.73 μg/L,Cd为1.55 μg/L,Cr为9.09 μg/L,Fe为142.65 μg/L.Pb、Cu、Cd、Cr受人为因素影响较大,主要来源于第二产业和第三产业,Zn和Fe受人类影响较小,Zn主要来源为天然源,Fe来源于混合源.

  8. Precipitation Matters

    Science.gov (United States)

    McDuffie, Thomas

    2007-01-01

    Although weather, including its role in the water cycle, is included in most elementary science programs, any further examination of raindrops and snowflakes is rare. Together rain and snow make up most of the precipitation that replenishes Earth's life-sustaining fresh water supply. When viewed individually, raindrops and snowflakes are quite…

  9. Investigation of the Large-Scale Atmospheric Moisture Field over the Midwestern United States in Relation to Summer Precipitation. Part II: Recycling of Local Evapotranspiration and Association with Soil Moisture and Crop Yields.

    Science.gov (United States)

    Zangvil, Abraham; Portis, Diane H.; Lamb, Peter J.

    2004-09-01

    The relative contributions of locally evapotranspired (i.e., recycled) moisture versus externally advected water vapor for the growing-season precipitation of the U.S. Corn Belt and surrounding areas (1.23 × 106 km2) are estimated in this paper. Four May August seasons with highly contrasting precipitation and crop yields (1975, 1976, 1979, and 1988) are investigated. A simple recycling equation—developed from the traditional atmospheric moisture budget and involving regional evapotranspiration and atmospheric water vapor inflow—is applied on daily, monthly, and seasonal time scales. Several atmospheric moisture budget components {moisture flux divergence [MFD], storage change [or change in precipitable water (dPW)], and inflow [IF]} are evaluated for 24-h periods using standard finite difference and line integral methods applied to objectively analyzed U.S. and Canadian rawinsonde data (50-hPa vertical resolution, surface to 300 hPa) for 0000 and 1200 UTC. Daily area-averaged precipitation (P) totals are derived from approximately 600 evenly distributed (but ungridded) recording rain gauges. Evapotranspiration (E) is estimated as the residual of the moisture budget equation for 24-h periods; values compare favorably with the few existing observations.Traditional budget results show the following: E is weakly related to P on monthly and seasonal time scales; there is surprising interannual constancy of seasonal E cycles and averages given the large variation in resulting crop yields; and monthly and seasonal variability of the export of the E - P surplus is determined largely by the horizontal velocity divergence component of MFD. New recycling analyses suggest that the contribution of local E to P (i.e., PE/P) is relatively small and remarkably consistent (largely 0.19 0.24) for monthly and seasonal periods, despite large P and crop yield variations. However, the monthly/seasonal averaging process is found to completely mask a striking decrease of daily PE

  10. ANALYTICAL CHARACTERIZATION OF PRECIPITATIONS

    Directory of Open Access Journals (Sweden)

    Danut Tiberiu Epure

    2011-02-01

    Full Text Available The properties of precipitation are mainly determined by solid, liquid and gaseous substances that exist in suspended or dissolved form. These substances come from many complex interactions between the atmosphere – hydrosphere – lithosphere – biota. The analytical characterization of precipitation has been based on the analysis of several chemical parameters: pH, conductivity, chloride, fluoride and ammonium ions, total hardness, alkalinity, H2S and sulphides, COD (Mn, nitrites, phosphorous, metallic ions (total iron, copper and chromium. In this purpose were collected rainwater, ice and snow from different areas (cities Năvodari, Constanţa, Buzău and Mihail Kogălniceanu during November 2007 till February 2008. This study shows that chemical characteristics of the analyzed water samples vary from one region to another depending on the mineralogical composition of zones crossed, the contact time, temperature, weather conditions, the sampling period (day or night and the nature of sample (rain, snow, ice.

  11. Precipitation Measurements from Space: The Global Precipitation Measurement Mission

    Science.gov (United States)

    Hou, Arthur Y.

    2007-01-01

    Water is fundamental to the life on Earth and its phase transition between the gaseous, liquid, and solid states dominates the behavior of the weather/climate/ecological system. Precipitation, which converts atmospheric water vapor into rain and snow, is central to the global water cycle. It regulates the global energy balance through interactions with clouds and water vapor (the primary greenhouse gas), and also shapes global winds and dynamic transport through latent heat release. Surface precipitation affects soil moisture, ocean salinity, and land hydrology, thus linking fast atmospheric processes to the slower components of the climate system. Precipitation is also the primary source of freshwater in the world, which is facing an emerging freshwater crisis in many regions. Accurate and timely knowledge of global precipitation is essential for understanding the behavior of the global water cycle, improving freshwater management, and advancing predictive capabilities of high-impact weather events such as hurricanes, floods, droughts, and landslides. With limited rainfall networks on land and the impracticality of making extensive rainfall measurements over oceans, a comprehensive description of the space and time variability of global precipitation can only be achieved from the vantage point of space. This presentation will examine current capabilities in space-borne rainfall measurements, highlight scientific and practical benefits derived from these observations to date, and provide an overview of the multi-national Global Precipitation Measurement (GPM) Mission scheduled to bc launched in the early next decade.

  12. Climate Prediction Center(CPC)Daily GOES Precipitation Index (GPI)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — GOES Precipitation Index (GPI) is a precipitation estimation algorithm. The GPI technique estimates tropical rainfall using cloud-top temperature as the sole...

  13. U.S. Hourly Precipitation Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hourly Precipitation Data (HPD) is digital data set DSI-3240, archived at the National Climatic Data Center (NCDC). The primary source of data for this file is...

  14. NESDIS Blended Total Precipitable Water (TPW) Products

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The blended Total Precipitable Water (TPW) product is derived from multiple sensors/satellites. The Percentage of TPW normal (PCT), or TPW anomaly, shows the...

  15. Precipitation Reconstruction over Land (PREC/L)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The monthly data set consists files of 3 resolutions of monthly averaged precipitation totals. The global analyses are defined by interpolation of gauge...

  16. U.S. Hourly Precipitation Data Publication

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This publication contains hourly precipitation amounts obtained from recording rain gages located at National Weather Service, Federal Aviation Administration, and...

  17. Perspectives of precipitation science: Part III

    Science.gov (United States)

    Michaelides, Silas

    2016-03-01

    This Special Issue of Atmospheric Research entitled "Perspectives of Precipitation Science: Part III" encompasses selected papers that were presented at the General Assembly of the European Geosciences Union, held in Vienna, Austria, from 27 April to 2 May 2014, within the framework of the (General) Session "Precipitation: Measurement, Climatology, Remote Sensing, and Modeling".

  18. The magnetic and oxidation behavior of bare and silica-coated iron oxide nanoparticles synthesized by reverse co-precipitation of ferrous ion (Fe{sup 2+}) in ambient atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Mahmed, N., E-mail: norsuria.mahmed@aalto.fi [Aalto University School of Chemical Technology, Department of Materials Science and Engineering, P.O. Box 16200, FI-00076 Aalto (Finland); School of Materials Engineering, Kompleks Pusat Pengajian UniMAP, Taman Muhibbah, Universiti Malaysia Perlis, 02600 Jejawi, Perlis (Malaysia); Heczko, O., E-mail: heczko@fzu.cz [Institute of Physics, Academy of Sciences, Czech Republic Na Slovance 2, CZ-182 21 Praha 8 (Czech Republic); Lancok, A., E-mail: Lancok@seznam.cz [Institute of Physics, Academy of Sciences, Czech Republic Na Slovance 2, CZ-182 21 Praha 8 (Czech Republic); Hannula, S-P., E-mail: simo-pekka.hannula@aalto.fi [Aalto University School of Chemical Technology, Department of Materials Science and Engineering, P.O. Box 16200, FI-00076 Aalto (Finland)

    2014-03-15

    The synthesis of iron oxide nanoparticles, i.e., magnetite was attempted by using only ferrous ion (Fe{sup 2+}) as a magnetite precursor, under an ambient atmosphere. The room temperature reverse co-precipitation method was used, by applying two synthesis protocols. The freshly prepared iron oxide was also immediately coated with Stöber silica (SiO{sub 2}) layer, forming the coreshell structure. The phase, stoichiometry, crystallite and the particle size of the synthesized powders were determined by using X-ray diffraction (XRD) and transmission electron microscope (TEM), while the magnetic and oxidation behaviors were studied by using the vibrating sample magnetometer (VSM) and Mössbauer spectroscopy. Based on the results, the bare iron oxide nanoparticles are in the stoichiometry between the magnetite and the maghemite stoichiometry, i.e., oxidation occurs. This oxidation is depending on the synthesis protocols used. With the silica coating, the oxidation can be prevented, as suggested by the fits of Mössbauer spectra and low temperature magnetic measurement. - Highlights: • Synthesis of magnetite was attempted by using ferrous ion (Fe{sup 2+}) in air. • The synthesized particle has a stoichiometry in between magnetite and maghemite. • Silica shell partly prevented the oxidation as suggested by magnetic and Mössbauer study.

  19. Eocene precipitation: a global monsoon?

    Science.gov (United States)

    Greenwood, D. R.; Huber, M.

    2011-12-01

    precipitation, with MAP >100cm/a, but with a significant summer peak, matching our Australian result. Much higher than present-day precipitation across much of Eocene Australia is consistent with higher atmospheric humidity in the Antarctic region in the Paleogene. High Paleogene precipitation around the globe (i.e., North and South America, Australia, Antarctica, China) is consistent with high Eocene atmospheric humidity, which would have contributed significantly to polar, and global, Eocene warming. These proxy data show a mix of match and mismatch with published model-generated estimates of precipitation for Australia and North America for the Eocene, and highlight how current models are still missing some component critical for modelling Eocene climate.

  20. Heavy Precipitation Events in Lithuania

    Science.gov (United States)

    Bukantis, A.; Rimkus, E.; Kažys, J.

    2010-09-01

    Analysis of heavy precipitation events in Lithuania is presented in this work. Research was divided into two parts. Spatial distribution and dynamic of heavy precipitation events in Lithuania during observation period (1961-2008) is presented in the first part and climate predictions for XXI century according to outputs of CCLM model are in the second. Daily data from 17 meteorological stations were used for the analysis of heavy precipitation events in Lithuania. Research covers period from 1961 to 2008. Annual and seasonal heavy precipitation values and the recurrence of extreme daily and 3-day precipitation events were analyzed. Spatial distribution of heavy precipitation events in Lithuania was determined; the trends of such precipitation recurrence were identified. Also, daily and 3-day annual maxima probabilities were calculated using the Generalized Extreme Value (GEV) distribution. 10, 30 and 100 years return period was analyzed. Finally, atmospheric circulation processes during heavy precipitation events were described using the adapted Hess & Brezowski macrocirculation form classification Predictions of changes of heavy precipitation recurrence in Lithuania are also presented in this study. Output data of the regional climate model CCLM (COSMO - Climate Limited-area Model) for the period 1971-2100 were used. Predictions were based on A1B and B1 emission scenarios. Despite of relatively small area and quite negligible differences in altitude there are significant unevenness in spatial distribution of heavy precipitation events in Lithuania. The mean annual number of cases when daily precipitation amount exceeded 10 mm fluctuates from 12.4 to 21.9 and from 5.3 to 10.5 when 3-day precipitation exceeded 20 mm. The probability of maximum precipitation amount for 10 year return period appears very familiar to spatial distribution of heavy precipitation recurrence: the highest values can be expected in the western part (55-60 mm daily and 75-85 mm in 3-days

  1. Circulation factors affecting precipitation over Bulgaria

    Science.gov (United States)

    Nojarov, Peter

    2015-09-01

    The objective of this paper is to determine the influence of circulation factors on precipitation in Bulgaria. The study succeeds investigation on the influence of circulation factors on air temperatures in Bulgaria, as the focus here is directed toward precipitation amounts. Circulation factors are represented through two circulation indices, showing west-east or south-north transport of air masses over Bulgaria and four teleconnection indices (patterns)—North Atlantic Oscillation, East Atlantic, East Atlantic/Western Russia, and Scandinavian. Omega values at 700-hPa level show vertical motions in the atmosphere. Annual precipitation trends are mixed and not statistically significant. A significant decrease of precipitation in Bulgaria is observed in November due to the strengthening of the eastward transport of air masses (strengthening of EA teleconnection pattern) and anticyclonal weather (increase of descending motions in the atmosphere). There is also a precipitation decrease in May and June due to the growing influence of the Azores High. An increase of precipitation happens in September. All this leads to a redistribution of annual precipitation course, but annual precipitation amounts remain the same. However, this redistribution has a negative impact on agriculture and winter ski tourism. Zonal circulation has a larger influence on precipitation in Bulgaria compared to meridional. Eastward transport throughout the year leads to lower than the normal precipitation, and vice versa. With regard to the four teleconnection patterns, winter precipitation in Bulgaria is determined mainly by EA/WR teleconnection pattern, spring and autumn by EA teleconnection pattern, and summer by SCAND teleconnection pattern.

  2. SMEX02 Atmospheric Aerosol Optical Properties Data

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set consists of observations of atmospheric parameters including spectral aerosol optical depths, precipitable water, sky radiance distributions and...

  3. Chemistry of United States precipitation. Final report on the national precipitation sampling network

    Energy Technology Data Exchange (ETDEWEB)

    Lodge, J.P. Jr.; Pate, J.B.; Basbergill, W.; Swanson, G.S.; Hill, K.C.; Lorange, E.; Lazrus, A.L.

    1968-01-01

    Atmospheric precipitation washes large quantities of particulate and gaseous materials from air, and thus provides a means of studying contamination of the atmosphere. The relationships between the concentration of constituents in air and their concentrations in precipitation are not known with quantitative certainty. However, it is believed that the concentration patterns of contaminants in precipitation reflect their patterns in air. Moreover, though analysis of precipitation water does not reveal absolute values for air contamination, it does provide a means of monitoring changes in contamination with time. The purposes of the project are: (1) to determine mean benchmark values of contaminants throughout the country; (2) to detect possible trends in these values over long periods of time; (3) to observe seasonal fluctuations and geographical distributions which may reveal the sources of these atmospheric contaminants. 48 references, 27 figures, 5 tables.

  4. Observation-Corrected Precipitation Estimates in GEOS-5

    Science.gov (United States)

    Reichle, Rolf H.; Liu, Qing

    2014-01-01

    Several GEOS-5 applications, including the GEOS-5 seasonal forecasting system and the MERRA-Land data product, rely on global precipitation data that have been corrected with satellite and or gauge-based precipitation observations. This document describes the methodology used to generate the corrected precipitation estimates and their use in GEOS-5 applications. The corrected precipitation estimates are derived by disaggregating publicly available, observationally based, global precipitation products from daily or pentad totals to hourly accumulations using background precipitation estimates from the GEOS-5 atmospheric data assimilation system. Depending on the specific combination of the observational precipitation product and the GEOS-5 background estimates, the observational product may also be downscaled in space. The resulting corrected precipitation data product is at the finer temporal and spatial resolution of the GEOS-5 background and matches the observed precipitation at the coarser scale of the observational product, separately for each day (or pentad) and each grid cell.

  5. Precipitation Climatology on Titan-like Exomoons.

    Science.gov (United States)

    Tokano, Tetsuya

    2015-06-01

    The availability of liquid water on the surface on Earth's continents in part relies on the precipitation of water. This implies that the habitability of exomoons has to consider not only the surface temperature and atmospheric pressure for the presence of liquid water, but also the global precipitation climatology. This study explores the sensitivity of the precipitation climatology of Titan-like exomoons to these moons' orbital configuration using a global climate model. The precipitation rate primarily depends on latitude and is sensitive to the planet's obliquity and the moon's rotation rate. On slowly rotating moons the precipitation shifts to higher latitudes as obliquity is increased, whereas on quickly rotating moons the latitudinal distribution does not strongly depend on obliquity. Stellar eclipse can cause a longitudinal variation in the mean surface temperature and surface pressure between the subplanetary and antiplanetary side if the planet's obliquity and the moon's orbital distance are small. In this particular condition the antiplanetary side generally receives more precipitation than the subplanetary side. However, precipitation on exomoons with dense atmospheres generally occurs at any longitude in contrast to tidally locked exoplanets. PMID:25796390

  6. Precipitation of Continental Origin over South America

    Science.gov (United States)

    Martinez-Agudelo, J. A.; Dominguez, F.

    2012-12-01

    The Amazon forest receives high amounts of moisture from the tropical Atlantic. A significant part of this moisture is returned back to the atmosphere by the forest, and further redistributed to the rest of the continent by the meridional flow imposed by the Andes. Thus, the land-atmosphere interaction between the Amazon forest and the large-scale flow affects not only the forest itself but also the downstream regions. We develop a method to quantify the precipitation of continental origin over South America, and identify the contribution that selected source regions make to continental precipitation. The average annual cycle of precipitation of continental origin for the five-year period 2000-2004 shows a band of high values aligned along the northwest-southeast direction, from southern Peru to northeastern Argentina. The lowest values of precipitation of continental origin occur upstream, over the northeastern coast of South America. Precipitation that originates as moisture from the Amazon forest shows maximum values over the western side of the Amazon, east of the Andes, especially over southern Peru. The Amazon forest also contributes to precipitation over La Plata River Basin (LPRB) and the Pacific coast of Colombia. During its dry season, up to 29.3% of the precipitation over LPRB originates as moisture from the Amazon forest. Throughout the year, the contributions to precipitation over LPRB by the Amazon forest and LPRB (recycled precipitation) are in the same range, but out of phase. The average contribution of the rest of the continent to precipitation over LPRB is smaller but of the same order as that of the Amazon and LPRB.

  7. Modelled Precipitation Over Greenland

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes the annual total precipitation from 1985 to 1999 and monthly total precipitation from January 1985 to December 1999. The data is derived from...

  8. Precipitation studies around Plant Bowen

    International Nuclear Information System (INIS)

    A program called METER (Meteorological Effects of Thermal Energy Releases) to investigate the atmospheric effects of the heat and moisture releases from large cooling towers and ponds, is reviewed. Results are reported from a precipitation modification study around the Plant Bowen (fossil-fuel power plant) in northwest Georgia which utilizes four natural-draft cooling towers. The study is composed of two parts: the statistical analysis of historic National Weather Service climatological data from the general area of the plant, and a field study involving, primarily, a high-density recording rain-gage network. Both parts are aimed toward obtaining quantitative estimates of potential plant-induced precipitation augmentation and storm pattern disruption

  9. Precipitation Frequency for Puerto Rico and the US Virgin Islands - NOAA Atlas 14 Volume 3

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This GIS grid atlas contains precipitation frequency estimates for Puerto Rico and the U.S. Virgin Islands is based on precipitation data collected between...

  10. Climate Prediction Center (CPC)Monthly Precipitation Reconstruction (PREC) at Spatial Resolution of 1 degree.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This global monthly precipitation analysis is called the Climate Prediction Center (CPC) Precipitation Reconstruction (PREC). This analysis consists of two...

  11. Climate Prediction Center (CPC)Monthly Precipitation Reconstruction (PREC) Spatial Resolution of 2.5 degree

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This global monthly precipitation analysis is called the Climate Prediction Center (CPC) Precipitation Reconstruction (PREC). This analysis consists of two...

  12. Precipitation Frequency for Semiarid Southwest, USA - NOAA Atlas 14 Volume 1

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This GIS grid atlas contains precipitation frequency estimates for the Semiarid Southwest based on precipitation data collected between 1893-2000. This atlas is an...

  13. Precipitation Frequency for American Samoa, Pacific Islands - NOAA Atlas 14 Volume 5

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This GIS grid atlas contains precipitation frequency estimates for the Pacific Islands that are based on precipitation data. This atlas is a new release from the...

  14. Precipitation Frequency for Pohnpei, Pacific Islands - NOAA Atlas 14 Volume 5

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This GIS grid atlas contains precipitation frequency estimates for the Pacific Islands that are based on precipitation data. This atlas is a new release from the...

  15. Precipitation Frequency for Northern Mariana Islands, Pacific Islands - NOAA Atlas 14 Volume 5

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This GIS grid atlas contains precipitation frequency estimates for the Pacific Islands that are based on precipitation data. This atlas is a new release from the...

  16. Precipitation Frequency for Palau, Pacific Islands - NOAA Atlas 14 Volume 5

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This GIS grid atlas contains precipitation frequency estimates for the Pacific Islands that are based on precipitation data. This atlas is a new release from the...

  17. Precipitation Frequency for Ohio River Basin, USA - NOAA Atlas 14 Volume 2

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This GIS grid atlas contains precipitation frequency estimates for the Ohio River Basin and Surrounding states is based on precipitation data collected between...

  18. Precipitation Frequency for Nukuoro, Pacific Islands - NOAA Atlas 14 Volume 5

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This GIS grid atlas contains precipitation frequency estimates for the Pacific Islands that are based on precipitation data. This atlas is a new release from the...

  19. Climate Prediction Center (CPC)Ensemble Canonical Correlation Analysis 90-Day Seasonal Forecast of Precipitation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Ensemble Canonical Correlation Analysis (ECCA) precipitation forecast is a 90-day (seasonal) outlook of US surface precipitation anomalies. The ECCA uses...

  20. Precipitation Frequency for Chuuk, Pacific Islands - NOAA Atlas 14 Volume 5

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This GIS grid atlas contains precipitation frequency estimates for the Pacific Islands that are based on precipitation data. This atlas is a new release from the...

  1. Global Precipitation Climatology Project (GPCP) - Pentad, Version 2.2

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Precipitation Climatology Project (GPCP) comprises a total of 27 products. The Version 2.2 Pentad product covers the period January 1979 to the present,...

  2. Precipitation Frequency Atlas of the Western United States

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Precipitation Frequency of the Western United States publication is an eleven volume set held in the archives. It was the culmination of many years of...

  3. TAO/TRITON, RAMA, and PIRATA Buoys, Daily, Precipitation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has daily Precipitation data from the TAO/TRITON (Pacific Ocean, http://www.pmel.noaa.gov/tao/), RAMA (Indian Ocean,...

  4. TAO/TRITON, RAMA, and PIRATA Buoys, Quarterly, Precipitation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has quarterly Precipitation data from the TAO/TRITON (Pacific Ocean, http://www.pmel.noaa.gov/tao/), RAMA (Indian Ocean,...

  5. Global Precipitation Climatology Project (GPCP) - Daily, Version 1.2

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Precipitation Climatology Project (GPCP) comprises a total of 27 products. The Version 1.2 Daily product covers the period October 1998 to the present,...

  6. Climate Prediction Center (CPC) U.S. Daily Precipitation Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Observational reports of daily precipitation (1200 UTC to 1200 UTC) are made by members of the NWS Automated Surface Observing Systems (ASOS) network; NWS...

  7. Global Precipitation Climatology Project (GPCP) - Monthly, Version 2.2

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Precipitation Climatology Project (GPCP) comprises a total of 27 products with the two primary products being the monthly satellite-gauge and associated...

  8. TAO/TRITON, RAMA, and PIRATA Buoys, Monthly, Precipitation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has monthly Precipitation data from the TAO/TRITON (Pacific Ocean, http://www.pmel.noaa.gov/tao/), RAMA (Indian Ocean,...

  9. An Electrostatic Precipitator System for the Martian Environment

    Science.gov (United States)

    Calle, C. I.; Mackey, P. J.; Hogue, M. D.; Johansen, M. R.; Phillips, J. R., III; Clements, J. S.

    2012-01-01

    Human exploration missions to Mars will require the development of technologies for the utilization of the planet's own resources for the production of commodities. However, the Martian atmosphere contains large amounts of dust. The extraction of commodities from this atmosphere requires prior removal of this dust. We report on our development of an electrostatic precipitator able to collect Martian simulated dust particles in atmospheric conditions approaching those of Mars. Extensive experiments with an initial prototype in a simulated Martian atmosphere showed efficiencies of 99%. The design of a second prototype with aerosolized Martian simulated dust in a flow-through is described. Keywords: Space applications, electrostatic precipitator, particle control, particle charging

  10. The study of plate-type electrostatic precipitators electrical supplies

    OpenAIRE

    Gabriel N. Popa; Corina Cunţan; Ovidiu Tirian; Dorin Roiban

    2005-01-01

    Stricter environmental legislation in many countries is producing standards governing the emission of fine particles to the atmosphere from all sources. The industrial separating particles from process streams have numerous methods with different principles. In electrostatic precipitators is used electrical charge of dust particles.There are many aspects of pollution control in both solid and liquid phase using electrostatic precipitators.The operation of plate-type electrostatic precipitator...

  11. Tensile properties of in-situ precipitated polydimethylsiloxane networks

    OpenAIRE

    Zhang, Z.; Y-L. Yue; Zhang, C.; Zhang, H.; D-H. Zhang; Chen, X.; Y-F. Chen

    2013-01-01

    Tensile propertiesof polydimethylsiloxane (PDMS) networks filled with in-situ precipitated silica were investigated. Experimental results showed that increasing the swelling time of cured rubber sheets in tetraethoxysilane (TEOS) solution or elevating the humidity and temperature of precipitation reaction atmosphere can render to a positive reinforcing effect. Moreover the in-situ precipitation method can be used to further enhance the tensile properties of fumed silica filled PDMS networks. ...

  12. Local influences on the composition of precipitation on Bermuda

    OpenAIRE

    Galloway, James N.; Tokos, Joseph J.; Knap, Anthony H.; Keene, William C.

    2011-01-01

    The understanding of atmospheric biogeochemical cycles in marine areas depends heavily on the collection and analysis of precipitation samples. However, collection of marine precipitation is difficult due to constraints on sampling locations. For example, the island of Bermuda has been used to characterize the composition of precipitation over the western north Atlantic Ocean. However, Bermuda is a small, heavily populated island and the possibility exists that local processes can influence t...

  13. The magnetic and oxidation behavior of bare and silica-coated iron oxide nanoparticles synthesized by reverse co-precipitation of ferrous ion (Fe.sup.2+./sup.) in ambient atmosphere

    Czech Academy of Sciences Publication Activity Database

    Mahmed, N.; Heczko, Oleg; Lančok, Adriana; Hannula, S.-P.

    2014-01-01

    Roč. 353, MAR (2014), s. 15-22. ISSN 0304-8853 R&D Projects: GA ČR(CZ) GAP107/11/0391 Institutional support: RVO:68378271 Keywords : reverseco-precipitation * ferrousion * magnetite * Mössbauer * silica Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.970, year: 2014 http://www.sciencedirect.com/science/article/pii/S0304885313007336

  14. Extreme precipitation events in a changing climate

    International Nuclear Information System (INIS)

    Canada's natural environment and built infrastructure are affected significantly by extreme weather events, with repercussions such as economic losses. The purpose of this presentation was to research whether these losses are due to greater societal vulnerability or climatic extremes or both, and to determine whether engineering design codes and standards need to be changed to ensure that infrastructure, such as dams, can withstand future climatic extremes. Environment Canada maintains long term climate and water observing networks and uses climate data in the development of building codes and engineering design standards and practices. Because of the variable nature of precipitation, the range of spatial scales, climate system influences and the importance of local topography on precipitation occurrence and amount, analyzing historical trends and making future projections for precipitation, particularly extremes, are challenging. This presentation discussed historical climate trends and future projections with reference to changes temperature, precipitation and precipitation extremes. In addition, extreme weather events and recent trends were discussed together with human influence on trends and projections. The presentation demonstrated how the climate in Canada has varied during the period of instrumental records. Future predictions for precipitation extremes were developed using climate models and statistical downscaling. The presentation also highlighted atmospheric hazards information under development for emergency preparedness and disaster management planning. It was concluded that future climate changes are inevitable and will likely affect the frequency of heavy precipitation events. 14 refs., 1 tab., 19 figs

  15. Comparison between POES energetic electron precipitation observations and riometer absorptions:implications for determining true precipitation fluxes

    OpenAIRE

    Rodger, Craig J.; Kavanagh, Andrew J.; Clilverd, Mark A.; Marple, Steve R.

    2013-01-01

    Energetic Electron Precipitation (EEP) impacts the chemistry of the middle atmosphere with growing evidence of coupling to surface temperatures at high latitudes. To better understand this link it is essential to have realistic observations to properly characterise precipitation and which can be incorporated into chemistry-climate models. The Polar-orbiting Operational Environmental Satellites (POES) detectors measure precipitating particles but only integral fluxes and only in a fraction of ...

  16. Strong increase in convective precipitation in response to higher temperatures

    DEFF Research Database (Denmark)

    Berg, P.; Moseley, C.; Härter, Jan Olaf Mirko

    2013-01-01

    higher temperature, faster than the rate of increase in the atmosphere's water-holding capacity, termed the Clausius-Clapeyron rate. Invigoration of convective precipitation (such as thunderstorms) has been favoured over a rise in stratiform precipitation (such as large-scale frontal precipitation) as a......Precipitation changes can affect society more directly than variations in most other meteorological observables, but precipitation is difficult to characterize because of fluctuations on nearly all temporal and spatial scales. In addition, the intensity of extreme precipitation rises markedly at...... cause for this increase , but the relative contributions of these two types of precipitation have been difficult to disentangle. Here we combine large data sets from radar measurements and rain gauges over Germany with corresponding synoptic observations and temperature records, and separate convective...

  17. Composition of Estonian atmosphere

    International Nuclear Information System (INIS)

    Atmospheric study, particularly that of its chemical composition, has a long tradition in Estonia. Since middle of this century, in addition to meteorological observations, some chemical compounds in precipitations have been regularly measured in many meteorological stations. The main aim was to acquire information about the state and dynamics of the atmosphere. Therefore, main attention was paid to monitoring chemical compounds which have a direct impact on the human environment. As energy production developed intensively and SO2 and NOx increased drastically in the atmosphere in acidic rock areas, like Scandinavia, the problem of acid rain became the most important environmental problem in Europe and North-America. As a consequence, monitoring the compounds of sulphur in precipitation was organized in Estonia. In the 1970 s, as related to large operating oil shale-based power plants, Estonia became a country , where emissions of sulphur compounds per capita were extremely high. In 1979, Estonia became a participant in the European Monitoring and Evaluation Programme - the network created to study transboundary air pollution. The aims of the precipitation chemistry study and the related problems of the formation and transformation of the atmospheric composition have varied over the years. But monitoring of pollutant (in particular, sulphur compound) loads has been a central issue. Over recent years, an attempt was made to estimate the spatial regularities of atmospheric impurities and their impact on the pH of mean monthly precipitations. Furthermore, calculations were provided to find out the origin of atmospheric impurities washed out in Estonia. Until the 1990 s, CO2, and some other greenhouse gas (GHG) emissions were not studied in Estonia. The first inventory of GHG for Estonia was provided in 1995 using the Intergovernmental Panel on Climate Change (IPCC) methodology

  18. Trends and variability in extreme precipitation indices over Maghreb countries

    Science.gov (United States)

    Tramblay, Y.; El Adlouni, S.; Servat, E.

    2013-12-01

    Maghreb countries are highly vulnerable to extreme hydrological events, such as floods and droughts, driven by the strong variability of precipitation. While several studies have analyzed the presence of trends in precipitation records for the Euro-Mediterranean basin, this study provides a regional assessment of trends on its southernmost shores. A database of 22 stations located in Algeria, Morocco and Tunisia with between 33 and 59 yr of daily precipitation records is considered. The change points and trends are analyzed for eleven climate indices, describing several features of the precipitation regime. The issue of conducting multiple hypothesis tests is addressed through the implementation of a false discovery rate procedure. The spatial and interannual variability of the precipitation indices at the different stations are analyzed and compared with large-scale atmospheric circulation patterns, including the North Atlantic Oscillation (NAO), western Mediterranean Oscillation (WEMO), Mediterranean Oscillation (MO) and El Niño-Southern Oscillation (ENSO). Results show a strong tendency towards a decrease of precipitation totals and wet days together with an increase in the duration of dry periods, mainly for Morocco and western Algeria. On the other hand, only a few significant trends are detected for heavy precipitation indices. The NAO and MO patterns are well correlated with precipitation indices describing precipitation amounts, the number of dry days and the length of wet and dry periods, whereas heavy precipitation indices exhibit a strong spatial variability and are only moderately correlated with large-scale atmospheric circulation patterns.

  19. Ground-Based Global Positioning System (GPS) Meteorology Integrated Precipitable Water Vapor (IPW)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Ground-Based Global Positioning System (GPS) Meteorology Integrated Precipitable Water Vapor (IPW) data set measures atmospheric water vapor using ground-based...

  20. Precipitation and floodiness

    Science.gov (United States)

    Stephens, E.; Day, J. J.; Pappenberger, F.; Cloke, H.

    2015-12-01

    There are a number of factors that lead to nonlinearity between precipitation anomalies and flood hazard; this nonlinearity is a pertinent issue for applications that use a precipitation forecast as a proxy for imminent flood hazard. We assessed the degree of this nonlinearity for the first time using a recently developed global-scale hydrological model driven by the ERA-Interim/Land precipitation reanalysis (1980-2010). We introduced new indices to assess large-scale flood hazard, or floodiness, and quantified the link between monthly precipitation, river discharge, and floodiness anomalies at the global and regional scales. The results show that monthly floodiness is not well correlated with precipitation, therefore demonstrating the value of hydrometeorological systems for providing floodiness forecasts for decision-makers. A method is described for forecasting floodiness using the Global Flood Awareness System, building a climatology of regional floodiness from which to forecast floodiness anomalies out to 2 weeks.

  1. Electrostatic Precipitation in Nearly Pure Gaseous Nitrogen

    Science.gov (United States)

    Buhler, Charles; Calle, Carlos; Clements, Sid; Cox, Bobby; Ritz, Mindy

    2008-01-01

    Electrostatic precipitation was performed in a nearly pure gaseous nitrogen system as a possible remedy for black dust contaminant from high pressure 6000 psi lines at the NASA Kennedy Space Center. The results of a prototype electrostatic precipitator that was built and tested using nitrogen gas at standard atmospheric pressures is presented. High voltage pulsed waveforms are generated using a rotating spark gap system at 30 Hz. A unique dust delivery system utilizing the Venturi effect was devised that supplies a given amount of dust per unit time for testing purposes.

  2. VARIATION AND SOURCE ANALYSIS OF ATMOSPHERIC ORGANIC ACIDS FROM PRECIPITATION AT DINGHU MOUNTAIN%鼎湖山降水有机酸的变化特征及影响因素分析

    Institute of Scientific and Technical Information of China (English)

    龙晓娟; 王雪梅; 朱圣洁; 王跃思; 董汉英; 黄忠良; 陈银洁; 鲍若峪; 吴志勇

    2011-01-01

    针对2009年3月至2010年2月于鼎湖山采集的大气湿沉降进行分析,旨在了解鼎湖山森林生态系统有机酸湿沉降变化特征及其影响因素.结果表明,研究期间鼎湖山甲酸、乙酸和乙二酸的当量平均浓度分别为4.12μeq.L-1、3.39μeq.L-1、2.51μeq.L-1,分别占已测定有机酸的41.1%、33.9%和25.0%;有机酸对降水酸度的总贡献为12.3%;有机酸湿沉降通量呈现湿季(4月—9月)高干季(10月—次年3月)低的季节性变化规律,湿季有机酸湿沉降通量占全年的70.8%.甲酸、乙酸和乙二酸的浓度呈显著正相关,而有机酸与无机离子的相关性不高.利用气团轨迹后推以及天气形势分析发现陆地性降水鼎湖山有机酸浓度略高于海洋性降水,陆地性降水中甲酸、乙酸和乙二酸的当量平均浓度分别为4.47μeq.L-1、3.44μeq.L-1、2.79μeq.L-1,分别是海洋性降水的1.2、1.0和1.2倍;海洋性降水中有机酸沉降负荷大,甲酸、乙酸和乙二酸沉降通量分别是陆地性降水的1.6、1.6和2.1倍.%Precipitation samples obtained from March 2009 to February 2010 at the Dinghu Mountain station,Guangdong Province,were analyzed to study wet deposition of organic acids and their origins.The results showed that the average concentrations of formic acid,acetic acid and oxalic acid were 4.12 μeq·L-1,3.39 μeq·L-1,and 2.51 μeq·L-1,respectively,which contributed to 41.1%,33.9% and 25.0% of total orgaic acids.The contribution of orgaic acids to the total free acidity of precipitation was 12.3%.Wet deposition flux of organic acids in wet seasons was higher than dry season,and contributed to 70.8% of total annual wet-deposition amount.Correlation coefficients among formic acid,acetic acid and oxalic acid were high,while the correlation coefficients with inorganic components were low.The results from back-trajectory analysis indicated that continental precipitation was the primary factor influencing organic acids in

  3. Precipitable water and vapor flux between Belem and Manaus

    International Nuclear Information System (INIS)

    The water vapor flux and precipitable water was computated over the natural Amazon forest in the stretch between Belem and Manaus for 1972. The atmospheric branch of hidrological cycle theory was applied and the most significant conclusions on an annual basis are: Atlantic Ocean water vapor contributes 52% to the regional precipitation and is significant the role played by local evapotranspiration in the precipitation in the area; there were signs of the phenomenon of water vapor recycling nearly throughout the year. Evapotranspiration contributes to 48% of the precipitations in the area studied. The real evapotranspiration estimated by this method was 1,000mm year -1

  4. A New Method for Near Real Time Precipitation Estimates Using a Derived Statistical Relationship between Precipitable Water Vapor and Precipitation

    Science.gov (United States)

    Roman, J.

    2015-12-01

    The IPCC 5th Assessment found that the predicted warming of 1oC would increase the risk of extreme events such as heat waves, droughts, and floods. Weather extremes, like floods, have shown the vulnerability and susceptibility society has to these extreme weather events, through impacts such as disruption of food production, water supply, health, and damage of infrastructure. This paper examines a new way of near-real time forecasting of precipitation. A 10-year statistical climatological relationship was derived between precipitable water vapor (PWV) and precipitation by using the NASA Atmospheric Infrared Sounder daily gridded PWV product and the NASA Tropical Rainfall Measuring Mission daily gridded precipitation total. Forecasting precipitation estimates in real time is dire for flood monitoring and disaster management. Near real time PWV observations from AIRS on Aqua are available through the Goddard Earth Sciences Data and Information Service Center. In addition, PWV observations are available through direct broadcast from the NASA Suomi-NPP ATMS/CrIS instrument, the operational follow on to AIRS. The derived climatological relationship can be applied to create precipitation estimates in near real time by utilizing the direct broadcasting capabilities currently available in the CONUS region. The application of this relationship will be characterized through case-studies by using near real-time NASA AIRS Science Team v6 PWV products and ground-based SuomiNet GPS to estimate the current precipitation potential; the max amount of precipitation that can occur based on the moisture availability. Furthermore, the potential contribution of using the direct broadcasting of the NUCAPS ATMS/CrIS PWV products will be demonstrated. The analysis will highlight the advantages of applying this relationship in near-real time for flash flood monitoring and risk management. Relevance to the NWS River Forecast Centers will be discussed.

  5. Temporal variation of extreme precipitation events in Lithuania

    Directory of Open Access Journals (Sweden)

    Egidijus Rimkus

    2011-05-01

    Full Text Available Heavy precipitation events in Lithuania for the period 1961-2008 were analysed. The spatial distribution and dynamics of precipitation extremes were investigated. Positive tendencies and in some cases statistically significant trends were determined for the whole of Lithuania. Atmospheric circulation processes were derived using Hess & Brezowski's classification of macrocirculation forms. More than one third of heavy precipitation events (37% were observed when the atmospheric circulation was zonal. The location of the central part of a cyclone (WZ weather condition subtype over Lithuania is the most common synoptic situation (27% during heavy precipitation events. Climatic projections according to outputs of the CCLM model are also presented in this research. The analysis shows that the recurrence of heavy precipitation events in the 21st century will increase significantly (by up to 22% in Lithuania.

  6. Application of MAGIC to Lake Redó (Central Pyrenees): an assessment of the effects of possible climate driven changes in atmospheric precipitation, base cation deposition, and weathering rates on lake water chemistry.

    OpenAIRE

    Ventura, Marc; Wright, Richard F.; Catalan, Jordi; Camarero, Lluís

    2004-01-01

    The process-oriented catchment-scale model MAGIC was used to simulate water chemistry at Lake Redó, a high mountain lake in the Central Pyrenees, Spain. Data on lakewater and atmospheric deposition chemistry for the period 1984-1998 were used to calibrate the model, which was then used to reconstruct past and to provide forecasts for three hypothetical future scenarios of deposition. Forecast scenarios considered several combinations of changes in S and N deposition due to abatement strategie...

  7. Cosmogenic radionuclides in the environment: 32Si in precipitation samples from the Jungfraujoch, production cross sections of 36Cl in Argon and modeling of the atmospheric 36Cl production

    International Nuclear Information System (INIS)

    The concentrations of the cosmogenic radionuclide 32Si were measured in four fresh snow samples from the Jungfraujoch in the Swiss Alps (3450 m asl.) to study the feasibility of measuring this potential dating nuclide with Accelerator Mass Spectrometry. This technique could reduce drastically the amount of material needed for measurements of 32Si concentrations in environmental samples in contrast to conventional radiometric detection. The measured 32Si concentrations in the snow samples were between 1.84 and 6.28 μBql-1. These values agree with other measurements of precipitation samples. The measured 32Si/Sitot ratios ranged from 2.5.10-17 to 2.3.10-15 and were thus below the present detection limit of about 10-14, showing that at present it is not possible to carry out AMS measurements of 32Si in precipitation samples. For the first time, experimental cross sections of the reaction 40Ar(p,X)36Cl have been determined for the proton energy range 16-590 MeV. These cross sections were measured using a gas target, a novel method which was tested successfully by irradiating nitrogen targets to confirm literature values of the N(p,X)7Be and N(p,X)10Be cross sections. In fact, good agreement was found between the obtained cross sections with those using solid targets. Production of several radionuclides in the reaction of proton with nickel were also measured. Comparison of these cross sections with literature data proved that the proton flux measurements carried out with ionization chambers were very accurate. The excitation function of the reaction 40Ar(p,X)36Cl exhibits two maxima at proton energies of 20 MeV for the (p,αn)reaction and 95 MeV for the (p,2p3n) reaction, with maximum cross sections of 105 mb and 53 mb, respectively. (author) figs., tabs., refs

  8. Thunderstorms and thunderstorm precipitations in southern Poland

    Directory of Open Access Journals (Sweden)

    Bielec-Bąkowska Zuzanna

    2014-09-01

    Full Text Available This paper addresses spatial and temporal variability in the occurrence of thunderstorms and related precipitation in southern Poland between 1951 and 2010. The analysis was based on thunderstorm observations and daily precipitation totals (broken down into the few ranges from 15 meteorological stations. It was found that precipitation accompanied an overwhelming majority of thunderstorms. The most frequent range of thunderstorm precipitation totals was 0.1–10.0 mm which accounted for 60% of all values while precipitation higher than 20.0 mm accounted only for ca. 8%. During the study period, long-term change in the number of days with thunderstorm precipitation within a certain range displayed no clear-cut trends. Exceptions included: 1 an increase in the number of days with thunderstorm precipitation in the lowest range of totals (0.1–10.0 mm at Katowice, Tarnów, Rzeszów and Lesko and decrease at Mt. Kasprowy Wierch, 2 an increase in the range 10.1–20.0 mm at Zakopane and 20.1–30.0 mm at Opole, 3 a decrease of the top range (more than 30.0 mm at Mt. Śnieżka. It was found that the heaviest thunderstorm precipitation events, i.e. totalling more than 30 mm, and those events that covered all or most of the study area, occurred at the time of air advection from the southern or eastern sectors and a passage of atmospheric fronts.

  9. Chemisorption And Precipitation Reactions

    Science.gov (United States)

    The transport and bioavailability of chemical components within soils is, in part, controlled by partitioning between solids and solution. General terms used to describe these partitioning reactions include chemisorption and precipitation. Chemisorption is inclusive of the suit...

  10. Precipitation Estimates for Hydroelectricity

    Science.gov (United States)

    Tapiador, Francisco J.; Hou, Arthur Y.; de Castro, Manuel; Checa, Ramiro; Cuartero, Fernando; Barros, Ana P.

    2011-01-01

    Hydroelectric plants require precise and timely estimates of rain, snow and other hydrometeors for operations. However, it is far from being a trivial task to measure and predict precipitation. This paper presents the linkages between precipitation science and hydroelectricity, and in doing so it provides insight into current research directions that are relevant for this renewable energy. Methods described include radars, disdrometers, satellites and numerical models. Two recent advances that have the potential of being highly beneficial for hydropower operations are featured: the Global Precipitation Measuring (GPM) mission, which represents an important leap forward in precipitation observations from space, and high performance computing (HPC) and grid technology, that allows building ensembles of numerical weather and climate models.

  11. Layer Precipitable Water (LPW) Briefing

    Science.gov (United States)

    Forsythe, John; Kidder, Stan; Fuell, Kevin; LeRoy, Anita

    2013-01-01

    Microwave Integrated Retrieval System (MIRS) provides soundings of specific humidity from a variety of instruments and is combined with AIRS infrared soundings to create a Layered Precipitable Water (LPW) composite product. The LPW provides vertical moisture information in the column instead of just upper levels via WV imagery, or a single column value via TPW products. LPW is created every 3 hours using the last 12 hours worth of data and has a delivery latency of 40 minutes. Weaknesses include discontinuities in the composite. Strengths include seeing through clouds, over land usage, and greater spatial coverage of vertical moisture profiles. Applications of LPW include analysis of horizontal and vertical moisture gradients, verification of NWP moisture, and analysis of atmospheric rivers and other moisture advection. Operational testbed is ongoing to determine viability of wider distribution.

  12. Study on Indicating Functions of the Atmospheric Circulation Indices and the Sea Surface Temperature for Annual Precipitation Forecast of Hulun Buir Region%大气环流指数和海温对呼伦贝尔地区年降水预测的指示意义

    Institute of Scientific and Technical Information of China (English)

    孙海滨; 高涛

    2012-01-01

    文章对近50a(1961—2010年)内蒙古呼伦贝尔地区的年、汛期和冬春季降水量和降水距平百分率(R%)作了统计,发现年R%和冬春季R%呈上升趋势,汛期R%略呈下降趋势;通过对年R%与大气环流指数、海温的相关分析发现:前期副热带高压(副高)、北半球极涡、大西洋欧洲环流C型、西藏高原位势高度和印缅槽(南支槽)强度指数等均与年R%密切相关,当北半球极涡收缩、强度减弱,副高扩张、强度加强,西藏高原位势高度偏高,南支槽减弱时,有利于来年呼伦贝尔地区降水,否则,相反。此外,前一年夏季北印度洋海域和赤道东太平洋海域海温对呼伦贝尔地区来年降水有显著影响,这两块海区的海温和上述环流指数可考虑作为呼伦贝尔地区年降水的预测信号使用。%The annual, rain-season and winter-spring precipitation and precipitation anomaly in percentage (R%) of Hulun Buir City (Region) in Inner Mongolia, China during the past 50 years (from 1961 to 2010) were calculated in this study. From the result of the calculation, it has been found that the annual and winter-spring R% display a significant increase trend. In opposite, the rain-season R%, however, shows a slight decrease trend during the 50-year period. Besides, it has been found in outcomes of the correlation analyses between the R% and all atmospheric circulation indices that the precious subtropical high (SH), North Polar vortex (NPV), Atlantic and Europe pattern C (Pattern-C), geopotential high of the Tibetan Plateau (GH-TP) and the India-Burma trough (IBT, also called South branch trough) have close connections with the R%. That indicates when the NPV is small and weak, the atmospheric circulation over the Atlantic and European region exhibits the Pattern-C, the GH-TP changes to higher than normal, the IBT is weak, the SH extends to north-westward and becomes strong in the previous time

  13. Processes affecting the stable isotope composition of calcite during precipitation on the surface of stalagmites: Laboratory experiments investigating the isotope exchange between DIC in the solution layer on top of a speleothem and the CO2 of the cave atmosphere

    Science.gov (United States)

    Dreybrodt, Wolfgang; Hansen, Maximilian; Scholz, Denis

    2016-02-01

    We present a theoretical derivation of the exchange time, τex, needed to establish isotopic equilibrium between atmospheric CO2 in a cave and HCO3- dissolved in a thin water film covering the surface of a speleothem. The result is τex = τredex · [HCO3-]/ (KH · pCO2 cave) , where τredex depends on the depth, a, of the water film and on temperature. [HCO3-] is the concentration of bicarbonate, pCO2 cave the partial pressure of CO2, and KH is Henry's constant. To test the theory we prepared stagnant or flowing thin films of a NaHCO3 solution and exposed them at 20 °C to an CO2 containing atmosphere of pCO2 500, 12,500, or 25,000 ppmV and defined isotope composition. The δ13C and δ18O values of the DIC in the solution were measured as a function of the exposure time. For stagnant films with depths between 0.06 and 0.2 cm the δ13C values exhibit an exponential approach towards isotope equilibrium with the atmospheric CO2 with exchange time, τex. The δ18O values first evolve towards isotopic equilibrium with atmospheric CO2, reach a minimum value and then drift away from the isotopic equilibrium with atmospheric CO2 approaching a steady state caused by isotopic exchange of oxygen with water. The experimental findings are in satisfactory agreement with the theoretical predictions. To further investigate isotope evolution in cave analogue conditions, a water film containing 5 mmol/L of NaHCO3 with a depth of 0.013 cm flowing down an inclined borosilicate glass plate was exposed to an atmosphere with pCO2 = 500 ppmV at a temperature of 20 °C. The δ13C and δ18O values were measured as a function of flow (exposure) time, t. The isotope compositions in the DIC of the water film decrease linear in time by δDIC (t) =δDIC (0) - (δDIC (0) -δDIC (∞)) · t /τex where δDIC (0) is the initial isotope composition of dissolved inorganic carbon (DIC) in the water film and δDIC (∞) its final value. From these data an exchange time τex of ca. 7000 s was obtained

  14. Localized precipitation and runoff on Mars

    OpenAIRE

    Kite, Edwin S.; Michaels, Timothy I.; Rafkin, Scot; Manga, Michael; Dietrich, William E

    2010-01-01

    We use the Mars Regional Atmospheric Modeling System (MRAMS) to simulate lake storms on Mars, finding that intense localized precipitation will occur for lake size >=10^3 km^2. Mars has a low-density atmosphere, so deep convection can be triggered by small amounts of latent heat release. In our reference simulation, the buoyant plume lifts vapor above condensation level, forming a 20km-high optically-thick cloud. Ice grains grow to 200 microns radius and fall near (or in) the lake at mean rat...

  15. Climate Prediction Center(CPC) Monthly Precipitation Reconstruction (PREC)at Spatial Resolution of 0.5 degree.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This global monthly precipitation analysis is called the Climate Prediction Center (CPC) Precipitation Reconstruction (PREC). This analysis consists of two...

  16. Climate Prediction Center (CPC) Monthly Precipitation Reconstruction of Ocean(PRECO)at Spatial Resolution of 2.5 degree.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This global monthly precipitation analysis is called the Climate Prediction Center (CPC) Precipitation Reconstruction (PREC). This analysis consists of two...

  17. Particle precipitation : effects on selected ionospheric phenomena

    OpenAIRE

    Lunde, June

    2009-01-01

    The motivation behind this thesis has been to study particle precipitation from the Sun into the Earth’s upper atmosphere and its effects on selected ionospheric phenomena. Particles from the solar wind can enter the Earth's magnetosphere through magnetic merging, either at the sub-solar point, or at higher latitudes, depending on the configuration of the interplanetary magnetic field. This interaction can be studied from the ground at Svalbard, due to its fortuitous location beneath the magn...

  18. ARM Cloud Aerosol Precipitation Experiment (ACAPEX) Science Plan

    Energy Technology Data Exchange (ETDEWEB)

    Leung, L. R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Prather, K. [Scripps Institution of Oceanography, La Jolla, CA (United States); Ralph, R. [National Oceanic and Atmospheric Administration, Washington, DC (United States); Rosenfeld, D. [The Hebrew University of Jerusalem (Israel); Spackman, R. [Science and Technology Corporation (STC), Hampton, VA (United States); DeMott, P. [Colorado State Univ., Fort Collins, CO (United States); Fairall, C. [National Oceanic and Atmospheric Administration, Washington, DC (United States); Fan, J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hagos, S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hughes, M. [National Oceanic and Atmospheric Administration, Washington, DC (United States); Long, C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rutledge, S. [Colorado State Univ., Fort Collins, CO (United States); Waliser, D. [National Aeronautics and Space Administration (NASA), Washington, DC (United States); Wang, H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-09-01

    The western U.S. receives precipitation predominantly during the cold season when storms approach from the Pacific Ocean. The snowpack that accumulates during winter storms provides about 70-90% of water supply for the region. Understanding and modeling the fundamental processes that govern the large precipitation variability and extremes in the western U.S. is a critical test for the ability of climate models to predict the regional water cycle, including floods and droughts. Two elements of significant importance in predicting precipitation variability in the western U.S. are atmospheric rivers and aerosols. Atmospheric rivers (ARs) are narrow bands of enhanced water vapor associated with the warm sector of extratropical cyclones over the Pacific and Atlantic oceans. Because of the large lower-tropospheric water vapor content, strong atmospheric winds and neutral moist static stability, some ARs can produce heavy precipitation by orographic enhancement during landfall on the U.S. West Coast. While ARs are responsible for a large fraction of heavy precipitation in that region during winter, much of the rest of the orographic precipitation occurs in post-frontal clouds, which are typically quite shallow, with tops just high enough to pass the mountain barrier. Such clouds are inherently quite susceptible to aerosol effects on both warm rain and ice precipitation-forming processes.

  19. Origins of the Earth's Diffuse Auroral Precipitation

    Science.gov (United States)

    Ni, Binbin; Thorne, Richard M.; Zhang, Xiaojia; Bortnik, Jacob; Pu, Zuyin; Xie, Lun; Hu, Ze-jun; Han, Desheng; Shi, Run; Zhou, Chen; Gu, Xudong

    2016-02-01

    The Earth's diffuse auroral precipitation provides the major source of energy input into the nightside upper atmosphere and acts as an essential linkage of the magnetosphere-ionosphere coupling. Resonant wave-particle interactions play a dominant role in the scattering of injected plasma sheet electrons, leading to the diffuse auroral precipitation. We review the recent advances in understanding the origin of the diffuse aurora and in quantifying the exact roles of various magnetospheric waves in producing the global distribution of diffuse auroral precipitation and its variability with the geomagnetic activity. Combined scattering by upper-and lower-band chorus accounts for the most intense inner magnetospheric electron diffuse auroral precipitation on the nightside. Dayside chorus can be responsible for the weaker dayside electron diffuse auroral precipitation. Pulsating auroras, the dynamic auroral structures embedded in the diffuse aurora, can be mainly caused by modulation of the excitation of lower band chorus due to macroscopic density variations in the magnetosphere. Electrostatic electron cyclotron harmonic waves are an important or even dominant cause for the nightside electron diffuse auroral precipitation beyond {˜}8Re and can also contribute to the occurrence of the pulsating aurora at high L-shells. Scattering by electromagnetic ion cyclotron waves could quite possibly be the leading candidate responsible for the ion precipitation (especially the reversed-type events of the energy-latitude dispersion) in the regions of the central plasma sheet and ring current. We conclude the review with a summary of current understanding, outstanding questions, and a number of suggestions for future research.

  20. Origins of the Earth's Diffuse Auroral Precipitation

    Science.gov (United States)

    Ni, Binbin; Thorne, Richard M.; Zhang, Xiaojia; Bortnik, Jacob; Pu, Zuyin; Xie, Lun; Hu, Ze-jun; Han, Desheng; Shi, Run; Zhou, Chen; Gu, Xudong

    2016-04-01

    The Earth's diffuse auroral precipitation provides the major source of energy input into the nightside upper atmosphere and acts as an essential linkage of the magnetosphere-ionosphere coupling. Resonant wave-particle interactions play a dominant role in the scattering of injected plasma sheet electrons, leading to the diffuse auroral precipitation. We review the recent advances in understanding the origin of the diffuse aurora and in quantifying the exact roles of various magnetospheric waves in producing the global distribution of diffuse auroral precipitation and its variability with the geomagnetic activity. Combined scattering by upper-and lower-band chorus accounts for the most intense inner magnetospheric electron diffuse auroral precipitation on the nightside. Dayside chorus can be responsible for the weaker dayside electron diffuse auroral precipitation. Pulsating auroras, the dynamic auroral structures embedded in the diffuse aurora, can be mainly caused by modulation of the excitation of lower band chorus due to macroscopic density variations in the magnetosphere. Electrostatic electron cyclotron harmonic waves are an important or even dominant cause for the nightside electron diffuse auroral precipitation beyond {˜}8Re and can also contribute to the occurrence of the pulsating aurora at high L-shells. Scattering by electromagnetic ion cyclotron waves could quite possibly be the leading candidate responsible for the ion precipitation (especially the reversed-type events of the energy-latitude dispersion) in the regions of the central plasma sheet and ring current. We conclude the review with a summary of current understanding, outstanding questions, and a number of suggestions for future research.

  1. Microbial biodiversity of the atmosphere

    Science.gov (United States)

    Klein, Ann Maureen

    Microorganisms are critical to the functioning of terrestrial and aquatic ecosystems and may also play a role in the functioning of the atmosphere. However, little is known about the diversity and function of microorganisms in the atmosphere. To investigate the forces driving the assembly of bacterial microbial communities in the atmosphere, I measured temporal variation in bacterial diversity and composition over diurnal and inter-day time scales. Results suggest that bacterial communities in the atmosphere markedly vary over diurnal time scales and are likely structured by inputs from both local terrestrial and long-distance sources. To assess the potential functions of bacteria and fungi in the atmosphere, I characterized total and potentially active communities using both RNA- and DNA-based data. Results suggest there are metabolically active microorganisms in the atmosphere that may affect atmospheric functions including precipitation development and carbon cycling. This dissertation includes previously published and unpublished co-authored material.

  2. Scaling of precipitation extremes with temperature in the French Mediterranean region: What explains the hook shape?

    OpenAIRE

    Drobinski, Philippe; Alonzo, Bastien; Bastin, Sophie; Da Silva, Nicolas; Muller, Caroline

    2016-01-01

    International audience Expected changes to future extreme precipitation remain a key uncertainty associated with anthropogenic climate change. Extreme precipitation has been proposed to scale with the precipitable water content in the atmosphere. Assuming constant relative humidity, this implies an increase of precipitation extremes at a rate of about 7% °C−1 globally as indicated by the Clausius-Clapeyron relationship. Increases faster and slower than Clausius-Clapeyron have also been rep...

  3. ANALYSIS OF PROJECTED FREQUENCY AND INTENSITY CHANGES OF PRECIPITATION IN THE CARPATHIAN REGION

    OpenAIRE

    KIS ANNA; PONGRÁCZ RITA; BARTHOLY JUDIT

    2015-01-01

    Precipitation is the major atmospheric source of surface water, thus, in order to build appropriate adaptation strategies for various economic sections related to water resources it is essential to provide projections for precipitation tendencies as exact as possible. Extreme precipitation events are especially important from this point of view since they may result in different environmental, economical, and/or even human health damages. Excessive precipitation for instance may induce floods...

  4. From precipitation to stream

    OpenAIRE

    Peralta-Tapia, Andres

    2015-01-01

    Understanding the journey water makes from precipitation entering a catchment, traveling through soils, and the time it takes before it exits as stream water are questions of great relevance for both scientists and environmental managers. Natural stable isotopes such as δ¹⁸O and δ²H have been extensively used over the last decades to trace water through diverse catchments across the world. In this thesis I analyzed over 2500 isotope samples to create long-term time series of precipitation and...

  5. Convective and stratiform precipitation trends in the Spanish Mediterranean coast

    Science.gov (United States)

    Ruiz-Leo, A. M.; Hernández, E.; Queralt, S.; Maqueda, G.

    2013-01-01

    Eastern Iberian Peninsula is characterized by the large occurrence of convective precipitation events, which entail important economic and social damage consequences. In order to prevent and minimize its effects, a good knowledge and understanding of the meteorological processes involved are necessary to be achieved. In this regard, an algorithm for classifying convective and stratiform precipitation components has been applied to a decadal precipitation record. Dataset were provided by National Spanish Meteorological Agency (AEMET) for the period 1998-2008. Hourly precipitation records have been analyzed. The goals of this study have been: a) to classify total precipitation into its stratiform and convective components in Levante region (located in the Eastern Spanish Coast) and b) to analyze annual and seasonal trends of such components. For determining both convective and stratiform precipitation components, a suitable exponential function has been used. After a computation process, critical precipitation intensity (so-called Rc) is obtained for each year and season of the studied period. Every precipitation episode in Levante region is classified into prevailing convective or stratiform regime according to the threshold value defined by Rc. The results obtained have been compared to Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA-COARE) to verify the validity of the algorithm. First results show an annual and seasonal significant positive trend in total precipitation and stratiform component for 1998-2008 decade. Further analysis reveals that convective precipitation exhibits no significant trend. Preliminary conclusions state that the total precipitation amount in Levante Region strongly depends on the stratiform component evolution.

  6. Precipitation from Space: Advancing Earth System Science

    Science.gov (United States)

    Kucera, Paul A.; Ebert, Elizabeth E.; Turk, F. Joseph; Levizzani, Vicenzo; Kirschbaum, Dalia; Tapiador, Francisco J.; Loew, Alexander; Borsche, M.

    2012-01-01

    otherwise possible. These developments have taken place in parallel with the growth of an increasingly interconnected scientific environment. Scientists from different disciplines can easily interact with each other via information and materials they encounter online, and collaborate remotely without ever meeting each other in person. Likewise, these precipitation datasets are quickly and easily available via various data portals and are widely used. Within the framework of the NASA/JAXA Global Precipitation Measurement (GPM mission, these applications will become increasingly interconnected. We emphasize that precipitation observations by themselves provide an incomplete picture of the state of the atmosphere. For example, it is unlikely that a richer understanding of the global water cycle will be possible by standalone missions and algorithms, but must also involve some component of data, where model analyses of the physical state are constrained alongside multiple observations (e.g., precipitation, evaporation, radiation). The next section provides examples extracted from the many applications that use various high-resolution precipitation products. The final section summarizes the future system for global precipitation processing.

  7. Global precipitation measurement (GPM)

    Science.gov (United States)

    Neeck, Steven P.; Flaming, Gilbert M.; Adams, W. James; Smith, Eric A.

    2001-12-01

    The National Aeronautics and Space Administration (NASA) is studying options for future space-based missions for the EOS Follow-on Era (post 2003), building upon the measurements made by Pre-EOS and EOS First Series Missions. One mission under consideration is the Global Precipitation Measurement (GPM), a cooperative venture of NASA, Japan, and other international partners. GPM will capitalize on the experience of the highly successful Tropical Rainfall Measurement Mission (TRMM). Its goal is to extend the measurement of rainfall to high latitudes with high temporal frequency, providing a global data set every three hours. A reference concept has been developed consisting of an improved TRMM-like primary satellite with precipitation radar and microwave radiometer to make detailed and accurate estimates of the precipitation structure and a constellation of small satellites flying compact microwave radiometers to provide the required temporal sampling of highly variable precipitation systems. Considering that DMSP spacecraft equipped with SSMIS microwave radiometers, successor NPOESS spacecraft equipped with CMIS microwave radiometers, and other relevant international systems are expected to be in operation during the timeframe of the reference concept, the total number of small satellites required to complete the constellation will be reduced. A nominal plan is to begin implementation in FY'03 with launches in 2007. NASA is presently engaged in advanced mission studies and advanced instrument technology development related to the mission.

  8. Application of MAGIC to Lake Redó (Central Pyrenees: an assessment of the effects of possible climate driven changes in atmospheric precipitation, base cation deposition, and weathering rates on lake water chemistry

    Directory of Open Access Journals (Sweden)

    Marc VENTURA

    2004-02-01

    Full Text Available The process-oriented catchment-scale model MAGIC was used to simulate water chemistry at Lake Redó, a high mountain lake in the Central Pyrenees, Spain. Data on lakewater and atmospheric deposition chemistry for the period 1984-1998 were used to calibrate the model, which was then used to reconstruct past and to provide forecasts for three hypothetical future scenarios of deposition. Forecast scenarios considered several combinations of changes in S and N deposition due to abatement strategies, and in base cation deposition due to climate-induced changes in air-mass trajectories from northern Africa. Scenario 1 assumed constant deposition of base cations at the present level plus the expected decrease in S and N deposition resulting from reduced emissions; scenario 2 (best case assumed an increase in base cation deposition plus the same decrease in S and N deposition as in scenario 1; scenario 3 (worst case assumed a decrease in base cation deposition plus no decrease in S and N deposition. The hindcast indicated that during the past 140-year period changes in lake water chemistry have been significant for a remote mountain catchment, although no substantial acidification has occurred. In this regard Lake Redó can be described as a "non-sensitive lake" maintaining a reference condition. The forecasts indicated changes that do not affect this status, but the trends, even if slight, were different between scenarios. A slight decline in the surface water ANC is predicted by Scenario 3. The N budget indicates an unusually low retention in the catchment, which may result in enhanced sensitivity to further increased N deposition. Some of the discrepancy between modelled and measured Ca2+ in lake water during 1984-98 could be explained by changes in rainfall amounts and by increased weathering rates due to increases in air temperature.

  9. Meteoric precipitations and slope instability in the mediterranean environment

    OpenAIRE

    Polemio, M.; CNR-IRPI, italy

    1993-01-01

    A long and intense international research activity has by now confirmed the basic role of atmospheric precipitations on the dynamics of landslides. This paper is within the framework of such an activity and describes how solid and liquid meteoric precipitations really affect landslides. A detailed study of the empirical hydrological methods aimed at the determination of exceptional meteoric events to be correlated with landslide is performed. Finally, based on the analysis of real cases occur...

  10. Predictability of seasonal precipitation in the Nordic region

    OpenAIRE

    Feddersen, Henrik

    2011-01-01

    Predictability of seasonal precipitation in the Nordic countries (Denmark, Finland, Iceland, Norwayand Sweden) is investigated using a nine-member ensemble of atmospheric general circulation modelsimulations with prescribed sea-surface temperature from October 1950 until March 1999. The simulationsand corresponding observations from 65 stations in the Nordic countries are used to identifylarge-scale patterns of seasonal precipitation, the predictability of which is investigated. Subsequently,...

  11. Atmospheric contamination

    International Nuclear Information System (INIS)

    It is about the levels of contamination in center America, the population's perception on the problem, effects of the atmospheric contamination, effects in the environment, causes of the atmospheric contamination, possibilities to reduce the atmospheric contamination and list of Roeco Swisscontac in atmospheric contamination

  12. Stochastic downscaling of precipitation: From dry events to heavy rainfalls

    Science.gov (United States)

    Vrac, M.; Naveau, P.

    2007-07-01

    Downscaling precipitation is a difficult challenge for the climate community. We propose and study a new stochastic weather typing approach to perform such a task. In addition to providing accurate small and medium precipitation, our procedure possesses built-in features that allow us to model adequately extreme precipitation distributions. First, we propose a new distribution for local precipitation via a probability mixture model of Gamma and Generalized Pareto (GP) distributions. The latter one stems from Extreme Value Theory (EVT). The performance of this mixture is tested on real and simulated data, and also compared to classical rainfall densities. Then our downscaling method, extending the recently developed nonhomogeneous stochastic weather typing approach, is presented. It can be summarized as a three-step program. First, regional weather precipitation patterns are constructed through a hierarchical ascending clustering method. Second, daily transitions among our precipitation patterns are represented by a nonhomogeneous Markov model influenced by large-scale atmospheric variables like NCEP reanalyses. Third, conditionally on these regional patterns, precipitation occurrence and intensity distributions are modeled as statistical mixtures. Precipitation amplitudes are assumed to follow our mixture of Gamma and GP densities. The proposed downscaling approach is applied to 37 weather stations in Illinois and compared to various possible parameterizations and to a direct modeling. Model selection procedures show that choosing one GP distribution shape parameter per pattern for all stations provides the best rainfall representation amongst all tested models. This work highlights the importance of EVT distributions to improve the modeling and downscaling of local extreme precipitations.

  13. Evaluation of Uncertainty in Precipitation Datasets for New Mexico, USA

    Science.gov (United States)

    Besha, A. A.; Steele, C. M.; Fernald, A.

    2014-12-01

    Climate change, population growth and other factors are endangering water availability and sustainability in semiarid/arid areas particularly in the southwestern United States. Wide coverage of spatial and temporal measurements of precipitation are key for regional water budget analysis and hydrological operations which themselves are valuable tool for water resource planning and management. Rain gauge measurements are usually reliable and accurate at a point. They measure rainfall continuously, but spatial sampling is limited. Ground based radar and satellite remotely sensed precipitation have wide spatial and temporal coverage. However, these measurements are indirect and subject to errors because of equipment, meteorological variability, the heterogeneity of the land surface itself and lack of regular recording. This study seeks to understand precipitation uncertainty and in doing so, lessen uncertainty propagation into hydrological applications and operations. We reviewed, compared and evaluated the TRMM (Tropical Rainfall Measuring Mission) precipitation products, NOAA's (National Oceanic and Atmospheric Administration) Global Precipitation Climatology Centre (GPCC) monthly precipitation dataset, PRISM (Parameter elevation Regression on Independent Slopes Model) data and data from individual climate stations including Cooperative Observer Program (COOP), Remote Automated Weather Stations (RAWS), Soil Climate Analysis Network (SCAN) and Snowpack Telemetry (SNOTEL) stations. Though not yet finalized, this study finds that the uncertainty within precipitation estimates datasets is influenced by regional topography, season, climate and precipitation rate. Ongoing work aims to further evaluate precipitation datasets based on the relative influence of these phenomena so that we can identify the optimum datasets for input to statewide water budget analysis.

  14. Sampling problems: The small scale structure of precipitation

    Science.gov (United States)

    Crane, R. K.

    1981-01-01

    The quantitative measurement of precipitation characteristics for any area on the surface of the Earth is not an easy task. Precipitation is rather variable in both space and time, and the distribution of surface rainfall data given location typically is substantially skewed. There are a number of precipitation process at work in the atmosphere, and few of them are well understood. The formal theory on sampling and estimating precipitation appears considerably deficient. Little systematic attention is given to nonsampling errors that always arise in utilizing any measurement system. Although the precipitation measurement problem is an old one, it continues to be one that is in need of systematic and careful attention. A brief history of the presently competing measurement technologies should aid us in understanding the problem inherent in this measurement task.

  15. ARM Cloud-Aerosol-Precipitation Experiment (ACAPEX) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Leung, L Ruby [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-03-01

    The U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility’s ARM Cloud-Aerosol-Precipitation Experiment (ACAPEX) field campaign contributes to CalWater 2015, a multi-agency field campaign that aims to improve understanding of atmospheric rivers and aerosol sources and transport that influence cloud and precipitation processes. The ultimate goal is to reduce uncertainties in weather predictions and climate projections of droughts and floods in California. With the DOE G-1 aircraft and ARM Mobile Facility 2 (AMF2) well equipped for making aerosol and cloud measurements, ACAPEX focuses specifically on understanding how aerosols from local pollution and long-range transport affect the amount and phase of precipitation associated with atmospheric rivers. ACAPEX took place between January 12, 2015 and March 8, 2015 as part of CalWater 2015, which included four aircraft (DOE G-1, National Oceanic and Atmospheric Administration [NOAA] G-IV and P-3, and National Aeronautics and Space Administration [NASA] ER-2), the NOAA research ship Ron Brown, carrying onboard the AMF2, National Science Foundation (NSF)-sponsored aerosol and precipitation measurements at Bodega Bay, and the California Department of Water Resources extreme precipitation network.

  16. Chemical Composition and Potential Sources of Water-Soluble Compounds in Atmospheric Precipitation in Xi'an in Spring and Summer%西安市春、夏季大气降水的化学组成和来源分析

    Institute of Scientific and Technical Information of China (English)

    田晶; 沈振兴; 张琨; 王昕; 曹军骥; 张婷

    2011-01-01

    为了探索西安市大气降水的水溶性化学组分浓度水平及来源,在春季和夏季采集了西安市降水样品,测定了样品中的水溶性无机离子和溶解性有机碳(DOC)的浓度,并对其来源进行了初步探讨.结果显示:春、夏季降水样品的平均pH值分别为5.85和5.83,表明西安市春、夏季降水酸度偏高,但尚未达到酸雨范畴;S2-4、Ca2+、NH+4和NO-3是降水中最主要的无机离子,在春季它们分别占总离子数的35.8%、28.2%、18%、9.1%,在夏季占总离子数的34%、25%、19%、8%.利用相关分析和富集因子法对降水中水溶性化学组分的来源进行了解析,结果表明,西安市春、夏季降水中水溶性化学组分主要来自燃煤、机动车尾气、建筑活动和生物质燃烧等人为因素.So2-4、NO-3当量比值变化揭示了机动车的快速增长、能源结构和燃烧方式的改变使得NO-3对降水酸度的贡献有相对增大的趋势.%Atmospheric precipitation samples collected in Xi'an in spring and summer were analyzed to determine the concentration levels of water-soluble inorganic ions and dissolved organic carbon (DOC).The average pH values in the precipitation were 5.85 in spring and 5.83 in summer, indicating that the precipitation samples were acidic but did not form acid rain.SO42-, Ca2+ ,NH4+, and NO3- were dominant in the water-soluble ions in the precipitation samples with the ion concentration of 35.8%, 28.2%, 18%, and 9.1% in spring and 34%, 25%, 19%, and 8% in summer, respectively.The analysis on the water-soluble components with the correlations and Enrichment factor shows that they are mainly from coal burning, vehicle exhaust emissions, construction activities, and biomass burning.In addition, The variation of SO42-/NO3- ratio confirms that the contribution of NO3- to the precipitation's acidity rises with the rapid growth of motor vehicles and the changes of energy structure and combustion methods.

  17. Reduction of tropical land region precipitation variability via transpiration

    Science.gov (United States)

    Lee, Jung-Eun; Lintner, Benjamin R.; Neelin, J. David; Jiang, Xianan; Gentine, Pierre; Boyce, C. Kevin; Fisher, Joshua B.; Perron, J. Taylor; Kubar, Terence L.; Lee, Jeonghoon; Worden, John

    2012-10-01

    Tropical rainforests are known to exhibit low intraseasonal precipitation variability compared with oceanic areas with similar mean precipitation in observations and models. In the present study, the potential role of transpiration for this difference in precipitation variability is investigated using the National Center for Atmospheric Research (NCAR) atmospheric general circulation model. Comparing model results with and without transpiration shows that in the absence of transpiration, mean precipitation decreases as may be expected. However the incidence of both higher daily total column water and more intense precipitation increases without transpiration; consequently the variability of precipitation increases substantially. These results can be understood in terms of the complex interplay of local near-surface and remote moist dynamical processes with both local positive (boundary-layer drying) and large-scale negative (increased large-scale convergence) feedbacks when transpiration is disabled in the model. It is also shown that surface turbulent fluxes over tropical rainforests are highly correlated with incoming solar energy but only weakly correlated with wind speed, possibly decoupling land precipitation from large-scale disturbances like the Madden-Julian Oscillation.

  18. Analysis of precipitation teleconnections in CMIP models as a measure of model fidelity in simulating precipitation

    Science.gov (United States)

    Langenbrunner, B.; Neelin, J.; Meyerson, J.

    2011-12-01

    The accurate representation of precipitation is a recurring issue in global climate models, especially in the tropics. Poor skill in modeling the variability and climate teleconnections associated with El Niño/Southern Oscillation (ENSO) also persisted in the latest Climate Model Intercomparison Project (CMIP) campaigns. Observed ENSO precipitation teleconnections provide a standard by which we can judge a given model's ability to reproduce precipitation and dynamic feedback processes originating in the tropical Pacific. Using CMIP3 Atmospheric Model Intercomparison Project (AMIP) runs as a baseline, we compare precipitation teleconnections between models and observations, and we evaluate these results against available CMIP5 historical and AMIP runs. Using AMIP simulations restricts evaluation to the atmospheric response, as sea surface temperatures (SSTs) in AMIP are prescribed by observations. We use a rank correlation between ENSO SST indices and precipitation to define teleconnections, since this method is robust to outliers and appropriate for non-Gaussian data. Spatial correlations of the modeled and observed teleconnections are then evaluated. We look at these correlations in regions of strong precipitation teleconnections, including equatorial S. America, the "horseshoe" region in the western tropical Pacific, and southern N. America. For each region and season, we create a "normalized projection" of a given model's teleconnection pattern onto that of the observations, a metric that assesses the quality of regional pattern simulations while rewarding signals of correct sign over the region. Comparing this to an area-averaged (i.e., more generous) metric suggests models do better when restrictions on exact spatial dependence are loosened and conservation constraints apply. Model fidelity in regional measures remains far from perfect, suggesting intrinsic issues with the models' regional sensitivities in moist processes.

  19. Localized precipitation and runoff on Mars

    CERN Document Server

    Kite, Edwin S; Rafkin, Scot; Manga, Michael; Dietrich, William E

    2010-01-01

    We use the Mars Regional Atmospheric Modeling System (MRAMS) to simulate lake storms on Mars, finding that intense localized precipitation will occur for lake size >=10^3 km^2. Mars has a low-density atmosphere, so deep convection can be triggered by small amounts of latent heat release. In our reference simulation, the buoyant plume lifts vapor above condensation level, forming a 20km-high optically-thick cloud. Ice grains grow to 200 microns radius and fall near (or in) the lake at mean rates up to 1.5 mm/hr water equivalent (maximum rates up to 6 mm/hr water equivalent). Because atmospheric temperatures outside the surface layer are always well below 273K, supersaturation and condensation begin at low altitudes above lakes on Mars. In contrast to Earth lake-effect storms, lake storms on Mars involve continuous precipitation, and their vertical velocities and plume heights exceed those of tropical thunderstorms on Earth. Convection does not reach above the planetary boundary layer for lakes O(10^2) mbar. In...

  20. Scientific investigations of atmospheric processes

    Science.gov (United States)

    1994-01-01

    Research was performed in atmospheric, dynamical, and thermodynamical processes and in other disciplines necessary to accomplish the following tasks: develop procedures for combining generalized radiative transfer codes with dynamic atmospheric model codes; perform diagnostic analysis of atmospheric processes to gain a better understanding of the evolution and development of mesoscale circulation systems and their precipitation structures; and to develop algorithms and software necessary to graphically display diagnostic sets on the MSFC McIDAS and EADS to facilitate scientific study and sensor capability evaluation. Research activities during this reporting period are detailed.

  1. Modeling solid-state precipitation

    CERN Document Server

    Nebylov, AlexanderKozeschnik, Ernst

    2012-01-01

    Over recent decades, modeling and simulation of solid-state precipitation has attracted increased attention in academia and industry due to their important contributions in designing properties of advanced structural materials and in increasing productivity and decreasing costs for expensive alloying. In particular, precipitation of second phases is an important means for controlling the mechanical-technological properties of structural materials. However, profound physical modeling of precipitation is not a trivial task. This book introduces you to the classical methods of precipitation model

  2. Atmospheric Science: It's More than Meteorology.

    Science.gov (United States)

    Smith, David R.; Krockover, Gerald H.

    1988-01-01

    Indicates that atmospheric science is not just forcasting the weather. Gives an overview of current topics in meteorology including ozone depletion, acid precipitation, winter cyclones, severe local storms, the greenhouse effect, wind shear and microbursts. Outlines the Atmospheric Sciences Education Program at Purdue University to produce…

  3. Integrated Precipitation and Hydrology Experiment (IPHEx)/Orographic Precipitation Processes Study Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Barros, A. P. [Duke Univ., Durham, NC (United States); Petersen, W. [National Aeronautics and Space Administration (NASA), Washington, DC (United States); Wilson, A. M. [Duke Univ., Durham, NC (United States)

    2016-04-01

    Three Microwave Radiometers (two 3-channel and one 2-channel) were deployed in the Southern Appalachian Mountains in western North Carolina as part of the Integrated Precipitation and Hydrology Experiment (IPHEx), which was the first National Aeronautics and Space Administration (NASA) Global Precipitation Mission (GPM) Ground Validation (GV) field campaign after the launch of the GPM Core Satellite (Barros et al. 2014). The radiometers were used along with other instrumentation to estimate the liquid water content of low-level clouds and fog. Specifically, data from the radiometers were collected to help, with other instrumentation, to characterize fog formation, evolution, and dissipation in the region (by monitoring the liquid water path in the column) and observe the effect of that fog on the precipitation regime. Data were collected at three locations in the Southern Appalachians, specifically western North Carolina: a valley in the inner mountain region, a valley in the open mountain pass region, and a ridge in the inner region. This project contributes to the U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility mission by providing in situ observations designed to improve the understanding of clouds and precipitation processes in complex terrain. The end goal is to use this improved understanding of physical processes to improve remote-sensing algorithms and representations of orographic precipitation microphysics in climate and earth system models.

  4. Precipitation Indices Low Countries

    Science.gov (United States)

    van Engelen, A. F. V.; Ynsen, F.; Buisman, J.; van der Schrier, G.

    2009-09-01

    Since 1995, KNMI published a series of books(1), presenting an annual reconstruction of weather and climate in the Low Countries, covering the period AD 763-present, or roughly, the last millennium. The reconstructions are based on the interpretation of documentary sources predominantly and comparison with other proxies and instrumental observations. The series also comprises a number of classifications. Amongst them annual classifications for winter and summer temperature and for winter and summer dryness-wetness. The classification of temperature have been reworked into peer reviewed (2) series (AD 1000-present) of seasonal temperatures and temperature indices, the so called LCT (Low Countries Temperature) series, now incorporated in the Millennium databases. Recently we started a study to convert the dryness-wetness classifications into a series of precipitation; the so called LCP (Low Countries Precipitation) series. A brief outline is given here of the applied methodology and preliminary results. The WMO definition for meteorological drought has been followed being that a period is called wet respectively dry when the amount of precipitation is considerable more respectively less than usual (normal). To gain a more quantitative insight for four locations, geographically spread over the Low Countries area (De Bilt, Vlissingen, Maastricht and Uccle), we analysed the statistics of daily precipitation series, covering the period 1900-present. This brought us to the following definition, valid for the Low Countries: A period is considered as (very) dry respectively (very) wet if over a continuous period of at least 60 days (~two months) cq 90 days (~three months) on at least two out of the four locations 50% less resp. 50% more than the normal amount for the location (based on the 1961-1990 normal period) has been measured. This results into the following classification into five drought classes hat could be applied to non instrumental observations: Very wet period

  5. Halogens in the atmosphere

    Science.gov (United States)

    Cicerone, R. J.

    1981-01-01

    Atmospheric halogen measurement data are presented for: (1) inorganic and organic gaseous compounds of chlorine, fluorine, bromine and iodine; and (2) chloride, fluoride, bromide and iodine in particulate form and in precipitation. The roles that these data and other, unavailable data play in the determination of the global cycles of the halogens are discussed. It is found that the speciation of the halogen gases in the troposphere is uncertain, with the only inorganic species detected by species-specific methods being HC1 and SF6. It is shown that heterogeneous reactions, both gas-to-particle and particle-to-gas processes, precipitation removal, and sea-salt aerosol generation and fractionation processes, need quantitative investigation to allow progress in estimating halogen sources and sinks. Where practical, quantitative comparisons are made between measured and predicted concentrations.

  6. Modelling precipitation extremes in climate change scenarios

    Czech Academy of Sciences Publication Activity Database

    Kyselý, Jan; Gaál, Ladislav; Beranová, Romana; Plavcová, Eva

    Patras: University of Patras, 2010 - (Argiriou, A.; Kazantzidis, A.), s. 833-838 ISBN 978-960-99254-0-2. [International Conference of Meteorology, Climatology and Atmospheric Physics (COMECAP2010) /10./. Patras (GR), 25.05.2010-28.05.2010] R&D Projects: GA AV ČR KJB300420801 Grant ostatní: ENSEMBLES(XE) 505539 Institutional research plan: CEZ:AV0Z30420517 Keywords : precipitation extremes * region-of-influence method * regional climate models Subject RIV: DG - Athmosphere Sciences, Meteorology

  7. Why does precipitation in northwest China show a significant increasing trend from 1960 to 2010?

    Science.gov (United States)

    Li, Baofu; Chen, Yaning; Chen, Zhongsheng; Xiong, Heigang; Lian, Lishu

    2016-01-01

    Based on monthly precipitation data from 74 weather stations in the arid region of northwest China, we employed statistical methods to analyse the characteristics of precipitation and investigated the relationships between precipitation and 11 atmospheric circulations. The results showed that the precipitation in northwest China had a significantly increasing trend (P China (- 0.16 mm/year) for the same period. Annual precipitation increased markedly after 1987, but the increase in precipitation gradually declined from north to south and from west to east. We found that the precipitation variation in spring, summer, autumn, and winter plays an important role in the yearly change, accounting for 21.6%, 42.4%, 18.4%, and 17.6%, respectively. The correlation analysis indicated that the annual precipitation revealed strong and significant associations with the West Pacific Subtropical High (WPSH, R = 0.60, P China.

  8. NOAA Climate Data Record (CDR) of Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN-CDR), Version 1 Revision 1

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — PERSIANN Precipitation Climate Data Record (PERSIANN-CDR) is a daily quasi-global precipitation product for the period of 1982 to 2011. The data covers from 60...

  9. Analysis of tropical sea surface temperature and atmospheric circulation anomalies and their relationship with abnormal precipitation in Yunnan during rainy season%云南雨季降水异常的热带海温和大气环流异常分析

    Institute of Scientific and Technical Information of China (English)

    谭晶; 王彰贵; 黄荣辉; 陈幸荣; 蔡怡; 黄勇勇

    2015-01-01

    Based on seven stations’ monthly precipitation data in Yunnan and the NCEP/NCAR monthly atmospheric circulation data, as well as ERSST V3b monthly sea surface temperature (SST) data, the Indian-Pacific SST mode that impacts Yunnan precipitation during rainy season was investigated using composite and correlation analysis. Of El Niño-Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) mode, which plays a more important role on Yunnan precipitation in rainy season? Finally, the physical mechanism through which Indian-Pacific SST mode impacts Yunnan precipitation in rainy season was discussed. The results are as follows. Both ENSO and IOD have influences on Yunnan precipitation in rainy season, but the IOD plays a more important role. When the western India Ocean’s SST is warmer (positive IOD), the easterly wind appears in the tropical Indian Ocean and a cyclonic anomalous circulation is in the western Indian Ocean. The warm and moist airflow in the western Indian Ocean enters the Mainland China along the west side of the Tibet Plateau, then goes around the Tibet Plateau and from the north to the south, and finally enters the Bay of Bengal, which limits the development of the trough over the Bay of Bengal. So, the water vapor transportation to Yunnan is less. Yunnan is in the water vapor flux divergence area and has less precipitation. When the tropical Indian Ocean has lower SST (negative IOD), no easterly wind is in the tropical Indian Ocean, the trough over the Bay of Bengal is strong, and the water vapor transportation to Yunnan is more; Yunnan is in the water vapor flux convergence area and has more precipitation.%利用云南地区32个站日降水量资料、NCEP/NCAR月平均大气环流资料和ERSST V3b的海表温度资料,利用合成分析、相关分析等方法,研究了影响云南雨季降水的太平洋-印度洋海温分布模态,并讨论了 ENSO 和热带印度洋偶极子(IOD)对云南雨季降水多寡影响的相对重要性

  10. Climate Change Characteristics of Free Atmospheric Humidity and Its Relationship with Temperature and Precipitation in Northeast China%东北高空湿度变化特征及其与地面气温和降水的关系

    Institute of Scientific and Technical Information of China (English)

    刘玉英; 李宇凡; 谢今范; 张红

    2016-01-01

    利用1971~2005年探空和地面观测资料,详细分析了东北地区高空比湿和相对湿度的时空变化特征,并探讨了比湿和相对湿度与地面气温、降水量的关系.结果表明:东北地区比湿空间分布主要受到水汽来源的影响,地面由东南向西北递减,高空由南向北递减;相对湿度受水汽、海拔高度和纬度的共同影响,地面和对流层下层由南向北先减后增,对流层中层由南向北递增,赤峰向通辽延伸的西南-东北向干舌地面最明显,随高度增加逐渐减弱.1971~2005年,东北地区比湿从地面到高空均为增加趋势,对流层中下层的增加趋势更加显著;相对湿度在地面呈显著减小趋势,对流层中层呈显著增加趋势.大气比湿与地面气温在年、季尺度上存在一致的显著正相关关系,大气相对湿度与地面气温在季节尺度上存在显著负相关关系;对流层中下层相对湿度与降水量相关最显著;地面气温升高对东北气候趋于干旱化起了重要作用,高空相对湿度增加有利于降水增加,气温与比湿的相互消长,影响了气候的干、湿变化.%In accordance with the data of radio sounding data and the data of surface temperature and precipita-tion in Northeast China in 1971-2005, the temporal and spatial change characteristics of free atmospheric spe-cific humidity and relative humidity as well as the relationship between humidity and surface temperature and precipitation are analyzed. The results indicate that, the spatial distribution of specific humidity is impacted by water vapor source in Northeast China, decreased from the southeast to the northwest on the ground, and de-creasing from the south to the north at upper air. The spatial distribution of relative humidity is impacted by wa-ter vapor, altitude and latitude, decreased firstly and then increased from the south to the north from the ground to lower layer of troposphere, increased from the south to the north in

  11. Fast and Slow Precipitation Responses to Individual Climate Forcers: A PDRMIP Multimodel Study

    Science.gov (United States)

    Samset, B. H.; Myhre, G.; Forster, P.M.; Hodnebrog, O.; Andrews, T.; Faluvegi, G.; Flaschner, D.; Kasoar, M.; Kharin, V.; Kirkevag, A.; Shindell, D.; Voulgarakis, A.

    2016-01-01

    Precipitation is expected to respond differently to various drivers of anthropogenic climate change. We present the first results from the Precipitation Driver and Response Model Intercomparison Project (PDRMIP), where nine global climate models have perturbed CO2, CH4, black carbon, sulfate, and solar insolation. We divide the resulting changes to global mean and regional precipitation into fast responses that scale with changes in atmospheric absorption and slow responses scaling with surface temperature change. While the overall features are broadly similar between models, we find significant regional intermodel variability, especially over land. Black carbon stands out as a component that may cause significant model diversity in predicted precipitation change. Processes linked to atmospheric absorption are less consistently modeled than those linked to top-of-atmosphere radiative forcing. We identify a number of land regions where the model ensemble consistently predicts that fast precipitation responses to climate perturbations dominate over the slow, temperature-driven responses.

  12. The Global Precipitation Climatology Project (GPCP) Combined Precipitation Dataset

    Science.gov (United States)

    Huffman, George J.; Adler, Robert F.; Arkin, Philip; Chang, Alfred; Ferraro, Ralph; Gruber, Arnold; Janowiak, John; McNab, Alan; Rudolf, Bruno; Schneider, Udo

    1997-01-01

    The Global Precipitation Climatology Project (GPCP) has released the GPCP Version 1 Combined Precipitation Data Set, a global, monthly precipitation dataset covering the period July 1987 through December 1995. The primary product in the dataset is a merged analysis incorporating precipitation estimates from low-orbit-satellite microwave data, geosynchronous-orbit -satellite infrared data, and rain gauge observations. The dataset also contains the individual input fields, a combination of the microwave and infrared satellite estimates, and error estimates for each field. The data are provided on 2.5 deg x 2.5 deg latitude-longitude global grids. Preliminary analyses show general agreement with prior studies of global precipitation and extends prior studies of El Nino-Southern Oscillation precipitation patterns. At the regional scale there are systematic differences with standard climatologies.

  13. Martian Environment Electrostatic Precipitator

    Science.gov (United States)

    McDougall, Michael Owen

    2016-01-01

    As part of the planned manned mission to Mars, NASA has noticed that shipping oxygen as a part of life support to keep the astronauts alive continuously is overly expensive, and impractical. As such, noting that the Martian atmosphere is 95.37% CO2, NASA chemists noted that one could obtain oxygen from the Martian atmosphere. The plan, as part of a larger ISRU (in-situ resource utilization) initiative, would extract water from the regolith, or the Martian soil which can be electrolyzed by solar panel produced voltage into hydrogen and oxygen. The hydrogen can then be used in the Sabatier reaction with carbon dioxide to produce methane and water producing a net reaction that does not lose water and outputs methane and oxygen for use as rocket fuel and breathing.

  14. The study of plate-type electrostatic precipitators electrical supplies

    Directory of Open Access Journals (Sweden)

    Gabriel N. Popa

    2005-10-01

    Full Text Available Stricter environmental legislation in many countries is producing standards governing the emission of fine particles to the atmosphere from all sources. The industrial separating particles from process streams have numerous methods with different principles. In electrostatic precipitators is used electrical charge of dust particles.There are many aspects of pollution control in both solid and liquid phase using electrostatic precipitators.The operation of plate-type electrostatic precipitators is closely related to its electrical energization, to obtain high collection efficiency with low electrical energization consumption. The paper analyze the traditional direct current energization, the intermittent energization, the pulse energization and the switched mode at high frequency power supplies of plate-type electrostatic precipitators sections.

  15. Tensile properties of in-situ precipitated polydimethylsiloxane networks

    Directory of Open Access Journals (Sweden)

    Z. Zhang

    2013-10-01

    Full Text Available Tensile propertiesof polydimethylsiloxane (PDMS networks filled with in-situ precipitated silica were investigated. Experimental results showed that increasing the swelling time of cured rubber sheets in tetraethoxysilane (TEOS solution or elevating the humidity and temperature of precipitation reaction atmosphere can render to a positive reinforcing effect. Moreover the in-situ precipitation method can be used to further enhance the tensile properties of fumed silica filled PDMS networks. The reinforcement introduced by the in-situ precipitated silica gel particles can probably be attributed to the adsorption of polymer chains onto silica surface, the pinning effect of polymer chains within gel particles, and the fillerfiller gel structure among gel particles.

  16. Modes of winter precipitation variability in the North Atlantic

    Energy Technology Data Exchange (ETDEWEB)

    Zorita, E. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Hydrophysik; Saenz, J.; Fernandez, J.; Zubillaga, J. [Bilbao Univ. (Spain)

    2001-07-01

    The modes of variability of winter precipitation in the North Atlantic sector are identified by Empirical Orthogonal Functions Analysis in the NCEP/NCAR global reanalysis data sets. These modes are also present in a gridded precipitation data set over the Western Europe. The large-scale fields of atmospheric seasonal mean circulation, baroclinic activity, evaporation and humidity transport that are connected to the rainfall modes have been also analyzed in order to investigate the physical mechanisms that are causally linked to the rainfall modes. The results indicate that the leading rainfall mode is associated to the North Atlantic oscillation and represents a meridional redistribution of precipitation in the North Atlantic through displacements of the storm tracks. The second mode is related to evaporation anomalies in the Eastern Atlantic that precipitate almost entirely in the Western Atlantic. The third mode seems to be associated to meridional transport of water vapor from the Tropical Atlantic. (orig.)

  17. Climate Prediction Center (CPC) Weekly U.S. Selected Cities Precipitation Summary

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Weekly U.S. reported precipitation amounts in hundredths of inches (ex 100 is 1.00 inches) generated from the GTS metar(hourly) and synoptic(6-hourly)observations...

  18. Climate Prediction Center (CPC) NCEP-Global Forecast System (GFS) Precipitation Forecast Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Forecast System (GFS) forecast precipitation data at 37.5km resolution is created at the NOAA Climate Prediction Center for the purpose of near real-time...

  19. Gridded 5km GHCN-Daily Temperature and Precipitation Dataset, Version 1

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Gridded 5km GHCN-Daily Temperature and Precipitation Dataset (nClimGrid) consists of four climate variables derived from the GHCN-D dataset: maximum...

  20. Climate Prediction Center (CPC)Weekly U.S. Precipitation and Temperature Summary

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Weekly U.S. minimum and maximum temperatures in whole degrees Fahrenheit and reported and estimated precipitation amounts in hundredths of inches(ex 100 is 1.00...

  1. Climate Prediction Center(CPC)Daily U.S. Precipitation and Temperature Summary

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Daily U.S. minimum and maximum temperatures in whole degrees Fahrenheit and reported and estimated precipitation amounts in hundredths of inches(ex 100 is 1.00...

  2. NESDIS Microwave Integrated Retrieval System (MIRS) ATMS Precipitation and Surface Products

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains two-dimensional precipitation and surface products from the NESDIS Microwave Integrated Retrieval System (MIRS) using sensor data from the...

  3. Daily Precipitation Sums at Coastal and Island Russian Arctic Stations, 1940-1990

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains precipitation data originally recorded in log books at 65 coastal and island meteorological stations, and later digitized at the Arctic and...

  4. Guidelines for the determination of selected trace metals in aerosols and in wet precipitation

    International Nuclear Information System (INIS)

    This publication describes sampling and analytical procedures suitable for the collection and analysis of representative samples of atmospheric aerosols and wet precipitation for selected trace metals. 11 refs, 2 tabs

  5. Monthly Total Precipitation Observation for Climate Prediction Center (CPC)Forecast Divisions

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This ASCII dataset contains monthly total precipitation for 102 Forecast Divisions within the conterminous U.S. It is derived from the monthly NCDC climate division...

  6. Climate Prediction Center(CPC) Monthly U.S. Precipitation and Temperature Summary

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monthly U.S. minimum and maximum temperatures in whole degrees Fahrenheit and reported and estimated precipitation amounts in hundredths of inches(ex 100 is 1.00...

  7. Gridded Mean Monthly Temperature and Precipitation Data for Alaska, British Columbia, and Yukon

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To aid in better understanding the temperature and precipitation data of the spatially variable climate of Alaska and Northwest Canada, this dataset was created via...

  8. Climate Prediction Center (CPC) Monthly U.S. Selected Cities Precipitation Summary

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monthly U.S. reported precipitation amounts in hundredths of inches (ex 100 is 1.00 inches) generated from the GTS metar(hourly) and synoptic(6-hourly)observations...

  9. TAO/TRITON, RAMA, and PIRATA Buoys, Quarterly, Evaporation Minus Precipitation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has quarterly Evaporation Minus Precipitation data from the TAO/TRITON (Pacific Ocean, http://www.pmel.noaa.gov/tao/), RAMA (Indian Ocean,...

  10. TAO/TRITON, RAMA, and PIRATA Buoys, 5-Day, Evaporation Minus Precipitation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has 5-day Evaporation Minus Precipitation data from the TAO/TRITON (Pacific Ocean, http://www.pmel.noaa.gov/tao/), RAMA (Indian Ocean,...

  11. 72-Hour Forecast of Precipitation Amounts from the National Weather Service's National Digital Forecast Database (NDFD)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Digital Forecast Database (NDFD) contains a seamless mosaic of the National Weather Service's (NWS) digital forecasts of precipitation amounts. In...

  12. 48-Hour Forecast of Precipitation Amounts from the National Weather Service's National Digital Forecast Database (NDFD)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Digital Forecast Database (NDFD) contains a seamless mosaic of the National Weather Service's (NWS) digital forecasts of precipitation amounts. In...

  13. Climate Prediction Center (CPC) Three Month Probabilistic Precipitation Outlook for the Contiguous United States and Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Climate Prediction Center (CPC) issues a series of thirteen probabilistic three-month precipitation outlooks for the United States. CPC issues the thirteen...

  14. TAO/TRITON, RAMA, and PIRATA Buoys, Monthly, Evaporation Minus Precipitation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has monthly Evaporation Minus Precipitation data from the TAO/TRITON (Pacific Ocean, http://www.pmel.noaa.gov/tao/), RAMA (Indian Ocean,...

  15. TAO/TRITON, RAMA, and PIRATA Buoys, Daily, Evaporation Minus Precipitation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has daily Evaporation Minus Precipitation data from the TAO/TRITON (Pacific Ocean, http://www.pmel.noaa.gov/tao/), RAMA (Indian Ocean,...

  16. A study of asphaltene solubility and precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Hong E.; Paul Watkinson [University of British Columbia, Vancouver, BC (Canada). Department of Chemical and Biological Engineering

    2004-10-01

    The effects of diluent composition on asphaltene precipitation from Cold Lake vacuum residue and Athabasca atmospheric tower bottoms were determined using the hot filtration method at 60-85{sup o}C. For selected mixtures the temperature range was extended to 300{sup o}C. The diluents include pure n-alkanes, a lube oil base-stock, a heavy vacuum gas oil and a resin-enriched fraction recovered from Cold Lake vacuum residue by supercritical fluid extraction and fractionation. The latter three complex diluents were tested alone and in blends, in order to cover a range of saturates from 56 to 99.4 wt%, aromatics from 0.6 to 25 wt%, and resins from 0 to 19 wt%. The scaling equation proposed by Rassamdana et al. in which the weight percent of asphaltenes precipitated is expressed as a function of alkane to feed ratio, and the alkane molecular mass, gave good agreement with the data for the pure alkane diluents. For the more complex diluents, an extension to the scaling equation was developed with two additional variables (the density and saturate content of the diluents). This equation provided good agreement with the data over a wide range of diluent to feed ratios. By the addition of the colloidal instability index of the feed oil into the variables of the scaling equation, the precipitation data from the two different feed oils could be correlated. 13 refs., 8 figs., 3 tabs.

  17. Stationary Eddies and the Zonal Asymmetry of Net Precipitation and Ocean Freshwater Forcing

    OpenAIRE

    Wills, Robert C.; Schneider, Tapio

    2015-01-01

    Transport of water vapor in the atmosphere generates substantial spatial variability of net precipitation (precipitation minus evaporation). Over half of the total spatial variability in annual-mean net precipitation is accounted for by deviations from the zonal mean. Over land, these regional differences determine differences in surface water availability. Over oceans, they account, for example, for the Pacific–Atlantic difference in sea surface salinity, with implications for th...

  18. Exoplanet Atmospheres

    CERN Document Server

    Seager, S

    2010-01-01

    At the dawn of the first discovery of exoplanets orbiting sun-like stars in the mid-1990s, few believed that observations of exoplanet atmospheres would ever be possible. After the 2002 Hubble Space Telescope detection of a transiting exoplanet atmosphere, many skeptics discounted it as a one-object, one-method success. Nevertheless, the field is now firmly established, with over two dozen exoplanet atmospheres observed today. Hot Jupiters are the type of exoplanet currently most amenable to study. Highlights include: detection of molecular spectral features; observation of day-night temperature gradients; and constraints on vertical atmospheric structure. Atmospheres of giant planets far from their host stars are also being studied with direct imaging. The ultimate exoplanet goal is to answer the enigmatic and ancient question, "Are we alone?" via detection of atmospheric biosignatures. Two exciting prospects are the immediate focus on transiting super Earths orbiting in the habitable zone of M-dwarfs, and u...

  19. Study of Heavy Metals in the Atmospheric Deposition in Zanjan, Iran

    OpenAIRE

    A.Sh Hasanalizadeh; M.S Sekhawatju; M.R Mehrasbi; Z Farahmand kia; Z Ramezanzadeh

    2010-01-01

    "n "nBackgrounds and Objectives : Heavy metals in dust can enter to the human body through ingestion andinhalation. They can pollute the water and soil resources via atmospheric precipitation and accumulate in the plants tissue and enter human body by water and food. The aim of this study was measurement of the heavy metals in wet and dry atmospheric precipitation and effects of pollution sources at the ground surface on the concentration of heavy metals in the atmospheric precipitations."nMa...

  20. Precipitation extremes under climate change

    CERN Document Server

    O'Gorman, Paul A

    2015-01-01

    The response of precipitation extremes to climate change is considered using results from theory, modeling, and observations, with a focus on the physical factors that control the response. Observations and simulations with climate models show that precipitation extremes intensify in response to a warming climate. However, the sensitivity of precipitation extremes to warming remains uncertain when convection is important, and it may be higher in the tropics than the extratropics. Several physical contributions govern the response of precipitation extremes. The thermodynamic contribution is robust and well understood, but theoretical understanding of the microphysical and dynamical contributions is still being developed. Orographic precipitation extremes and snowfall extremes respond differently from other precipitation extremes and require particular attention. Outstanding research challenges include the influence of mesoscale convective organization, the dependence on the duration considered, and the need to...

  1. Dependence of variability in winter wheat productivity subject to air temperature and precipitation total

    OpenAIRE

    G. A. Starodvorov; I. D. Sokolov; O. A. Mostovyi

    2006-01-01

    Data of influence of the average monthly temperatures and monthly precipitation total on productivity of winter wheat in the Lugansk region for 60 years are presented. The atmospheric temperature and precipitation have decisive importance in dynamics of the winter wheat’s crop-producing power.

  2. The tritium content of precipitation and surface water in Austria in 1995

    International Nuclear Information System (INIS)

    This report includes weighted monthly 3H means from 24 precipitation sampling stations, 3H concentrations of daily precipitation samples from the station Wien-Arsenal, and 3H concentrations of monthly samples from 17 surface water sampling stations. In addition 3H concentrations of hydrogen and water vapor in the atmosphere at Vienna since 1991 are presented. (author)

  3. Pluto's atmosphere

    International Nuclear Information System (INIS)

    Airborne CCD photometer observations of Pluto's June 9, 1988 stellar occultation have yielded an occultation lightcurve, probing two regions on the sunrise limb 2000 km apart, which reveals an upper atmosphere overlying an extinction layer with an abrupt upper boundary. The extinction layer may surround the entire planet. Attention is given to a model atmosphere whose occultation lightcurve closely duplicates observations; fits of the model to the immersion and emersion lightcurves exhibit no significant derived atmosphere-structure differences. Assuming a pure methane atmosphere, surface pressures of the order of 3 microbars are consistent with the occultation data. 43 references

  4. Atmospheric electricity

    CERN Document Server

    Chalmers, J Alan

    1957-01-01

    Atmospheric Electricity brings together numerous studies on various aspects of atmospheric electricity. This book is composed of 13 chapters that cover the main problems in the field, including the maintenance of the negative charge on the earth and the origin of the charges in thunderstorms. After a brief overview of the historical developments of atmospheric electricity, this book goes on dealing with the general principles, results, methods, and the MKS system of the field. The succeeding chapters are devoted to some aspects of electricity in the atmosphere, such as the occurrence and d

  5. Altitude precipitation gradient in Serbia

    Directory of Open Access Journals (Sweden)

    Živković Nenad M.

    2004-01-01

    Full Text Available Using average annual precipitations data for period 1961-90. from all rain gauges in Serbia, southern of Sava and Danube rivers, the map of altitude precipitations gradient is constructed. 59 regions homogeneous for relation X=f(H are obtained by regression analysis method (two-dimensional type, X precipitation height and H - altitude. Some new method are applied, some limitations are shown, some regularities are found in disposition of precipitation growth and it is indicated on practical application of this method in physico-geographical research.

  6. Electrical operation of electrostatic precipitators

    CERN Document Server

    Parker, Ken

    2003-01-01

    The electrostatic precipitator remains on of the most cost effective means of controlling the emission of particulates from most industrial processes. This book will be of interest to both users and suppliers of electrostatic precipitators as well as advanced students on environmental based courses. The author identifies the physical and engineering basis for the development of electrical equipment for electrostatic precipitators and thoroughly explores the technological factors which optimize the efficiency of the precipitator and hence minimize emissions, as well as future developments in th

  7. Photochemistry of Pluto's Atmosphere

    Science.gov (United States)

    Krasnopolsky, Vladimir A.

    1999-01-01

    This work include studies of two problems: (1) Modeling thermal balance, structure. and escape processes in Pluto's upper atmosphere. This study has been completed in full. A new method, of analytic solution for the equation of hydrodynamic flow from in atmosphere been developed. It was found that the ultraviolet absorption by methane which was previously ignored is even more important in Pluto's thermal balance than the extreme ultraviolet absorption by nitrogen. Two basic models of the lower atmosphere have been suggested, with a tropopause and a planetary surface at the bottom of the stellar occultation lightcurve, respectively, Vertical profiles, of temperature, density, gas velocity, and the CH4 mixing ratio have been calculated for these two models at low, mean, and high solar activity (six models). We prove that Pluto' " s atmosphere is restricted to 3060-4500 km, which makes possible a close flyby of future spacecraft. Implication for Pluto's evolution have also been discussed. and (2) Modeling of Pluto's photochemistry. Based on the results of (1), we have made some changes in the basic continuity equation and in the boundary conditions which reflect a unique can of hydrodynamic escape and therefore have not been used in modeling of other planetary atmospheres. We model photochemistry of 44 neutral and 23 ion species. This work required solution of a set of 67 second-order nonlinear ordinary differential equations. Two models have been developed. Each model consists of the vertical profiles for 67 species, their escape and precipitation rates. These models predict the chemical structure and basic chemical processes in the current atmosphere and possible implication of these processes for evolution. This study has also been completed in full.

  8. Copper precipitates in silicon: Precipitation, dissolution and chemical state

    International Nuclear Information System (INIS)

    The precipitation and dissolution of copper impurities at oxygen precipitates and stacking faults in silicon were studied using thermal budgets commensurate with standard integrated circuit processing. Additionally, in order to develop a better understanding of the dissolution process, we have obtained results on the chemical state of the copper precipitates. The goal of this work was to determine the feasibility of removing and maintaining copper impurities away from the active device region of an integrated circuit device by use of oxygen precipitates and stacking faults in the bulk of the material. Based on our results, we provide a basis for a predictive understanding of copper precipitation and dissolution in silicon and we discuss the feasibility of copper impurity control in silicon integrated circuit devices

  9. Comparing the Degree of Land-Atmosphere Interaction in Four Atmospheric General Circulation Models

    Science.gov (United States)

    Koster, Randal D.; Dirmeyer, Paul A.; Hahmann, Andrea N.; Ijpelaar, Ruben; Tyahla, Lori; Cox, Peter; Suarez, Max J.; Houser, Paul R. (Technical Monitor)

    2001-01-01

    Land-atmosphere feedback, by which (for example) precipitation-induced moisture anomalies at the land surface affect the overlying atmosphere and thereby the subsequent generation of precipitation, has been examined and quantified with many atmospheric general circulation models (AGCMs). Generally missing from such studies, however, is an indication of the extent to which the simulated feedback strength is model dependent. Four modeling groups have recently performed a highly controlled numerical experiment that allows an objective inter-model comparison of land-atmosphere feedback strength. The experiment essentially consists of an ensemble of simulations in which each member simulation artificially maintains the same time series of surface prognostic variables. Differences in atmospheric behavior between the ensemble members then indicates the degree to which the state of the land surface controls atmospheric processes in that model. A comparison of the four sets of experimental results shows that feedback strength does indeed vary significantly between the AGCMs.

  10. The physical drivers of historical and 21st century global precipitation changes

    International Nuclear Information System (INIS)

    Historical and 21st century global precipitation changes are investigated using data from the fifth Coupled Model Intercomparison Project (CMIP5) Atmosphere-Ocean-General-Circulation-Models (AOGCMs) and a simple energy-balance model. In the simple model, precipitation change in response to a given top-of-atmosphere radiative forcing is calculated as the sum of a response to the surface warming and a direct ‘adjustment’ response to the atmospheric radiative forcing. This simple model allows the adjustment in global mean precipitation to atmospheric radiative forcing from different forcing agents to be examined separately and emulates the AOGCMs well. During the historical period the AOGCMs simulate little global precipitation change despite an increase in global temperature—at the end of the historical period, global multi-model mean precipitation has increased by about 0.03 mm day−1, while the global multi-model mean surface temperature has warmed by about 1 K, both relative to the pre-industrial control means. This is because there is a large direct effect from CO2 and black carbon atmospheric forcing that opposes the increase in precipitation from surface warming. In the 21st century scenarios, the opposing effect from black carbon declines and the increase in global precipitation due to surface warming dominates. The cause of the spread between models in the global precipitation projections (which can be up to 0.25 mm day−1) is examined and found to come mainly from uncertainty in the climate sensitivity. The spatial distribution of precipitation change is found to be dominated by the response to surface warming. It is concluded that AOGCM global precipitation projections are in line with expectations based on our understanding of how the energy and water cycles are physically linked. (letters)

  11. Global precipitation response to changing external forcings since 1870

    Directory of Open Access Journals (Sweden)

    A. Bichet

    2011-03-01

    Full Text Available Predicting and adapting to changes in the hydrological cycle is one of the major challenges for the twenty-first century. To better estimate how it will respond to future changes in climate forcings, it is crucial to understand how it has evolved in the past and why. In our study, we use an atmospheric global climate model with prescribed sea surface temperatures (SSTs to investigate how changing external climate forcings have affected global land temperature and precipitation in the period 1870–2005. We show that prescribed SSTs (encapsulating other forcings are the dominant forcing driving the decadal variability of land temperature and precipitation since 1870. On top of this SSTs forcing, we also find that the atmosphere-only response to increasing aerosol emissions is a reduction in global land temperature and precipitation by up to 0.4 °C and 30 mm year−1, respectively, between about 1930 and 2000. Similarly, the atmosphere-only response to increasing greenhouse gas concentrations is an increase in global land temperature and precipitation by up to 0.25 °C and 10 mm year−1, respectively, between about 1950 and 2000. Finally, our results also suggest that between about 1950 and 1970, increasing aerosol emissions had a larger impact on the hydrological cycle than increasing greenhouse gases concentrations.

  12. Effects of El Nino Modoki on winter precipitation in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Do-Woo [Korea Meteorological Administration, National Institute of Meteorological Research, Seoul (Korea, Republic of); Choi, Ki-Seon [Korea Meteorological Administration, National Typhoon Center, Jeju (Korea, Republic of); Byun, Hi-Ryong [Pukyong National University, Department of Environmental Atmospheric Sciences, Nam-gu, Busan (Korea, Republic of)

    2012-04-15

    This study compares the impacts of El Nino Modoki and El Nino on precipitation over Korea during the boreal winters from 1954 to 2009. Precipitation in Korea tends to be equal to or greater than the normal level during an El Nino Modoki winter, whereas there is no significant change during an El Nino winter. Greater than normal precipitation during El Nino Modoki was also found over the lower reaches of the Yangtze River, China and much of southern Japan. The latitudes of these regions are 5-10 further north than in southern China, where precipitation increases during El Nino. The following two anomalous atmospheric circulations were found to be causes that led to different precipitation distributions over East Asia. First, an atmospheric wave train in the lower troposphere, which propagated from the central tropical Pacific (cyclonic) through the southern Philippine Sea (anticyclonic) to East Asia (cyclonic), reached the southern China and northern Philippine Sea during El Nino, whereas it reached Korea and southern Japan during El Nino Modoki. Second, an anomalous local meridional circulation, which consists of air sinking in the tropics, flowing poleward in the lower troposphere, and rising in the subtropics, developed between the southern Philippine Sea and northern Philippine Sea during El Nino. During El Nino Modoki, however, this circulation expanded further to the north and was formed between the southern Philippine Sea and regions of Korea and southern Japan. (orig.)

  13. Middlemiocenemonsoon Precipitation Seasonality In Thailand Using Rhino-teethoxygenisotopes

    Science.gov (United States)

    Bentaleb, I.; Kaandorp, R.; Tafforeau, P.; Ducrocq, S.; Chaimanee, Y.; Jaeger, J. J.; Ganssen, G.

    The present climate of Thailand is controlled by the Southeast Asian Monsoon system. Different time spans have been suggested for the first monsoon occurrence or intensification, from 30 Ma to the end of the Miocene (8-6 Ma) due to different hypotheses such as (i) Paratethys ocean shrinkage, (ii) Himalayan and Tibetan plateau uplift and (iii) chemical weathering and atmospheric [CO2]. One of the most appropriate way to study the past Monsoon occurrence is to reconstruct seasonal 18 paleo-precipitation distribution. We first calibrated a modern rhino tooth enamel18? O signal with seasonal precipitation amounts in Thailand. We show that the ? O of the rhino tooth is a powerful precipitation/evaporation proxy merely because the mammal hydroxylapatite precipitates under constant body temperature (no temperature corrections are needed). We applied the same high resolution analysis to a middle Miocene Thai specimen. The results show that middle Miocene seasonality in rainfall was similar to today (ca. 3 months), although the amount of precipitation was higher, which is in agreement with atmospheric general circulation model simulations suggesting at least an early monsoon installation.

  14. Comparison between POES energetic electron precipitation observations and riometer absorptions: Implications for determining true precipitation fluxes

    Science.gov (United States)

    Rodger, Craig J.; Kavanagh, Andrew J.; Clilverd, Mark A.; Marple, Steve R.

    2013-12-01

    electron precipitation (EEP) impacts the chemistry of the middle atmosphere with growing evidence of coupling to surface temperatures at high latitudes. To better understand this link, it is essential to have realistic observations to properly characterize precipitation and which can be incorporated into chemistry-climate models. The Polar-orbiting Operational Environmental Satellite (POES) detectors measure precipitating particles but only integral fluxes and only in a fraction of the bounce loss cone. Ground-based riometers respond to precipitation from the whole bounce loss cone; they measure the cosmic radio noise absorption (CNA), a qualitative proxy with scant direct information on the energy flux of EEP. POES observations should have a direct relationship with ΔCNA and comparing the two will clarify their utility in studies of atmospheric change. We determined ionospheric changes produced by the EEP measured by the POES spacecraft in ~250 overpasses of an imaging riometer in northern Finland. The ΔCNA modeled from the POES data is 10-15 times less than the observed ΔCNA when the >30 keV flux is reported as <106 cm-2 s-1 sr-1. Above this level, there is relatively good agreement between the space-based and ground-based measurements. The discrepancy occurs mostly during periods of low geomagnetic activity, and we contend that weak diffusion is dominating the pitch angle scattering into the bounce loss cone at these times. A correction to the calculation using measurements of the trapped flux considerably reduces the discrepancy and provides further support to our hypothesis that weak diffusion leads to underestimates of the EEP.

  15. Improved ethanol precipitation of DNA.

    Science.gov (United States)

    Fregel, Rosa; González, Ana; Cabrera, Vicente M

    2010-04-01

    In this Short Communication, a shorter version of the standard DNA ethanol precipitation and purification protocol is described. It uses a mixture of 70% ethanol, 75 mM ammonium acetate and different concentrations of different carriers to perform DNA precipitation and washing in only one step. PMID:20336673

  16. Resistivity Problems in Electrostatic Precipitation

    Science.gov (United States)

    White, Harry J.

    1974-01-01

    The process of electrostatic precipitation has ever-increasing application in more efficient collection of fine particles from industrial air emissions. This article details a large number of new developments in the field. The emphasis is on high resistivity particles which are a common cause of poor precipitator performance. (LS)

  17. Precipitation in the Solar System

    Science.gov (United States)

    McIntosh, Gordon

    2007-01-01

    As an astronomy instructor, I am always looking for commonly observed Earthly experiences to help my students and me understand and appreciate similar occurrences elsewhere in the solar system. Recently I wrote a short TPT article on frost. This paper is on the related phenomena of precipitation. Precipitation, so common on most of the Earth's…

  18. Robust direct effect of carbon dioxide on tropical circulation and regional precipitation

    Science.gov (United States)

    Bony, Sandrine; Bellon, Gilles; Klocke, Daniel; Sherwood, Steven; Fermepin, Solange; Denvil, Sébastien

    2013-06-01

    Predicting the response of tropical rainfall to climate change remains a challenge. Rising concentrations of carbon dioxide are expected to affect the hydrological cycle through increases in global mean temperature and the water vapour content of the atmosphere. However, regional precipitation changes also closely depend on the atmospheric circulation, which is expected to weaken in a warmer world. Here, we assess the effect of a rise in atmospheric carbon dioxide concentrations on tropical circulation and precipitation by analysing results from a suite of simulations from multiple state-of-the-art climate models, and an operational numerical weather prediction model. In a scenario in which humans continue to use fossil fuels unabated, about half the tropical circulation change projected by the end of the twenty-first century, and consequently a large fraction of the regional precipitation change, is independent of global surface warming. Instead, these robust circulation and precipitation changes are a consequence of the weaker net radiative cooling of the atmosphere associated with higher atmospheric carbon dioxide levels, which affects the strength of atmospheric vertical motions. This implies that geo-engineering schemes aimed at reducing global warming without removing carbon dioxide from the atmosphere would fail to fully mitigate precipitation changes in the tropics. Strategies that may help constrain rainfall projections are suggested.

  19. Method of precipitating uranium peroxide

    International Nuclear Information System (INIS)

    The uranium dissolved as uranyl tricarbonate ion in an aqueous alkaline solution is precipitated out as uranium peroxide. The precipitation is carried out by acidifying a portion of the aqueous alkaline solution with excess sulfuric acid to convert the uranyl tricarbonate ion to the uranyl ion and carbon dioxide. This is followed by the addition of hydrogen peroxide to the acidified solution to convert the uranyl ion to uranium peroxide precipitate, producing additional acid. Concurrently, a different portion of the aqueous alkaline uranyl tricarbonate solution is added to the precipitating solution to elevate the pH to an acidic range which is optimum for effective reaction to uranium peroxide and for its precipitation

  20. Regions of strong coupling between soil moisture and precipitation.

    Science.gov (United States)

    Koster, Randal D; Dirmeyer, Paul A; Guo, Zhichang; Bonan, Gordon; Chan, Edmond; Cox, Peter; Gordon, C T; Kanae, Shinjiro; Kowalczyk, Eva; Lawrence, David; Liu, Ping; Lu, Cheng-Hsuan; Malyshev, Sergey; McAvaney, Bryant; Mitchell, Ken; Mocko, David; Oki, Taikan; Oleson, Keith; Pitman, Andrew; Sud, Y C; Taylor, Christopher M; Verseghy, Diana; Vasic, Ratko; Xue, Yongkang; Yamada, Tomohito

    2004-08-20

    Previous estimates of land-atmosphere interaction (the impact of soil moisture on precipitation) have been limited by a lack of observational data and by the model dependence of computational estimates. To counter the second limitation, a dozen climate-modeling groups have recently performed the same highly controlled numerical experiment as part of a coordinated comparison project. This allows a multimodel estimation of the regions on Earth where precipitation is affected by soil moisture anomalies during Northern Hemisphere summer. Potential benefits of this estimation may include improved seasonal rainfall forecasts. PMID:15326351

  1. Precipitation Extremes: Considerations for Anthropogenically-forced Future Changes

    Science.gov (United States)

    Kunkel, K.; Young, J.

    2015-12-01

    The Third National Climate Assessment states that "increases in the frequency and intensity of extreme precipitation events are projected for all U.S. regions". While that general statement was made with high confidence, the practical implications for decision-makers are much less clear. In particular, engineering design needs quantitative estimates of probable maximum precipitation (PMP) and intensity-duration-frequency (IDF) values for the future in order to optimize runoff control structures for future climate conditions. This can be realized by simply analyzing the precipitation data from global climate model simulations of the future. However, confidence in the resulting values suffers from the known issues with GCM simulation of precipitation. In addition, skepticism about the accuracy of climate models negatively affects potential adoption of revised values in the engineering design community. We contend that scientists need a multi-pronged approach to develop PMP/IDF values that can be defended, explained, and promoted in order to maximize societal benefits and avoid catastrophic events. This talk will discuss considerations that could/should form the basis for design values. While global-warming induced increases in atmospheric water vapor content are nearly certain and form the foundation for expected increases in extreme precipitation, they most likely will be modulated by changes in global atmospheric dynamics and the consequent effects on local weather system climatology. This can be seen currently in the unexplained regional variations in recent trends in extreme precipitation frequency and intensity. We need to be able to understand recent trends, when greenhouse gas forcing of the climate systems has been rapidly increasing, in order to produce confident projections of future extreme precipitation.

  2. Pacific SST influence on spring precipitation in Addis Ababa, Ethiopia

    Science.gov (United States)

    Eden, J. M.; Widmann, M.; Wild, S.; Evans, G. R.; Hughes, J. G.

    2012-04-01

    In Ethiopia and other parts of East Africa, interannual variability of seasonal precipitation is dependent on variations in sea surface temperature (SST) and atmospheric circulation on both regional and global scales. The majority of research into large-scale atmospheric controls and predictability has focused on the heavier summer rains and the establishment of links to large-scale modes of climate variability such as ENSO. By contrast, relatively little work has focused on the potential for predictability of rainfall during the spring months, which is of great importance to much of southern Ethiopia. Additionally, failure of the spring rains may have important agricultural implications, particularly for crops requiring the full extent of the spring-summer growing season. Here, we analyse the links between Pacific SST and precipitation in Addis Ababa, Ethiopia for a century-long period (1900-2004). A tripole correlation pattern between spring precipitation and SST is found in the Pacific basin. We develop regression-based models to estimate spring precipitation from Pacific SST with a lead time of 2-3 months. When subject to a rigorous cross-validation, models based on principal component multiple linear regression (PC-MLR) calibrated on Pacific SST during December show good skill in reproducing observed temporal variability in Addis Ababa precipitation during February (r = 0.48) and March (r = 0.40), and the period spanning February to April (r = 0.44). Reconstructed precipitation is correlated with temperature and specific humidity in the surrounding region; estimates of heavy spring precipitation are associated with anomalously warm, moist conditions across the western Indian Ocean. Our findings suggest that inclusion of Pacific SST in predictive models may benefit drought forecasting across Ethiopia. The relationships identified provide a potential basis for forecasting models for spring rainfall and further analysis may focus on drought forecasting using ROC

  3. Impact of precipitation intermittency on NAO-temperature signals in proxy records

    Directory of Open Access Journals (Sweden)

    M. Casado

    2012-10-01

    Full Text Available In mid and high latitudes, the stable isotope ratio in precipitation is driven by changes in temperature, which controls atmospheric distillation. This relationship forms the basis for many continental paleoclimatic reconstructions using direct (e.g. ice cores or indirect (e.g. tree ring cellulose, speleothem calcite archives of past precipitation. However, the archiving process is inherently biased by precipitation intermittency. Here, we use two sets of atmospheric reanalyses (NCEP and ERA-interim to quantify this precipitation intermittency bias, by comparing seasonal (winter and summer temperatures estimated with and without precipitation weighting. We show that this bias can reach locally 6 to 10 °C and has large inter-annual variability. We then assess the impact of precipitation intermittency on the strength and stability of temporal correlations between seasonal temperatures and the North Atlantic Oscillation. Precipitation weighting reduces the correlation between winter NAO and temperature in some areas (e.g. Québec, South-East USA, East Greenland, East Siberia, Mediterranean sector but does not alter the main patterns of correlation. The importance of the precipitation intermittency bias with respect to other processes affecting precipitation isotopic composition is further analysed using outputs of an atmospheric general circulation model enabled with stable isotopes and nudged to reanalyses (LMDZiso. In winter, LMDZiso shows similar correlation values between the NAO and both the precipitation weighted temperature and precipitation δ18O, thus suggesting limited impacts of moisture origin. Correlations of comparable magnitude are obtained for the available observational evidence (GNIP and Greenland ice core data. Our findings support the use of archives of past precipitation δ18O for past NAO reconstructions.

  4. Articulating Atmospheres

    DEFF Research Database (Denmark)

    Kinch, Sofie

    2011-01-01

    This paper presents an architectural approach to designing computational interfaces by articulating the notion of atmosphere in the field of interaction design. It draws upon the concept of kinesthetic interaction and a philosophical notion on atmosphere emphasizing the importance of bodily...... experience in space, presented as middle ground experience. In the field of HCI, middle ground experiences complete the unarticulated spectrum between designing for foreground of attention or background awareness. When “Articulating Atmospheres through Middle Ground Experiences in Interaction Design......” implications and qualities of the approach are identified through concrete examples of a design case, which also investigates the qualities and implications of addressing atmospheres both as design concern and user experience....

  5. Exoplanetary Atmospheres

    CERN Document Server

    Madhusudhan, Nikku; Fortney, Jonathan; Barman, Travis

    2014-01-01

    The study of exoplanetary atmospheres is one of the most exciting and dynamic frontiers in astronomy. Over the past two decades ongoing surveys have revealed an astonishing diversity in the planetary masses, radii, temperatures, orbital parameters, and host stellar properties of exoplanetary systems. We are now moving into an era where we can begin to address fundamental questions concerning the diversity of exoplanetary compositions, atmospheric and interior processes, and formation histories, just as have been pursued for solar system planets over the past century. Exoplanetary atmospheres provide a direct means to address these questions via their observable spectral signatures. In the last decade, and particularly in the last five years, tremendous progress has been made in detecting atmospheric signatures of exoplanets through photometric and spectroscopic methods using a variety of space-borne and/or ground-based observational facilities. These observations are beginning to provide important constraints...

  6. Low-pressure systems and extreme precipitation in central India: sensitivity to temperature changes

    Science.gov (United States)

    Sørland, Silje Lund; Sorteberg, Asgeir

    2016-07-01

    Extreme rainfall events in the central Indian region are often related to the passage of synoptic scale monsoon low-pressure systems (LPS). This study uses the surrogate climate change method on ten monsoon LPS cases connected to observed extreme rainfall events, to investigate how sensitive the precipitation and runoff are to an idealized warmer and moister atmosphere. The ten cases are simulated with three different initial and lateral boundary conditions: the unperturbed control run, and two sets of perturbed runs where the atmospheric temperature is increased uniformly throughout the atmosphere, the specific humidity increased according to Clausius Clapeyron's relation, but the large-scale flow is unchanged. The difference between the control and perturbed simulations are mainly due to the imposed warming and feedback influencing the synoptic flow. The mean precipitation change with warming in the central Indian region is 18-20 %/K, with largest changes at the end of the LPS tracks. The LPS in the warmer runs are bringing more moisture further inland that is released as precipitation. In the perturbed runs the precipitation rate is increasing at all percentiles, and there is more frequent rainfall with very heavy intensities. This leads to a shift in which category that contributes most to the total precipitation: more of the precipitation is coming from the category with very heavy intensities. The runoff changes are similar to the precipitation changes, except the response in intensity of very heavy runoff, which is around twice the change in intensity of very heavy precipitation.

  7. Staging atmospheres

    DEFF Research Database (Denmark)

    Bille, Mikkel; Bjerregaard, Peter; Sørensen, Tim Flohr

    2015-01-01

    . Nevertheless, people’s experience of the environment is sought manipulated in a variety of contexts, often without offering a less ‘true’ experience of a situation than if it had not been manipulated by people. In fact, orchestrations of space are often central to sociality, politics and aesthetics. This...... introduction seeks to outline how a number of scholars have addressed the relationship between staged atmospheres and experience, and thus highlight both the philosophical, social and political aspects of atmospheres...

  8. Sensitivity of summer precipitation to tropical sea surface temperatures over East Asia in the GRIMs GMP

    Science.gov (United States)

    Chang, Eun-Chul; Yeh, Sang-Wook; Hong, Song-You; Wu, Renguang

    2013-05-01

    In this study, uncoupled atmospheric general circulation model experiments are conducted to examine the sensitivity of tropical Ocean basins from the Indian Ocean to the tropical Pacific Ocean on the summer precipitation variability over East Asia. It is remarkable that the Indian Ocean basin sea surface temperature (SST) and the tropical Pacific basin SST act on summer precipitation variability over Northeast Asia and southern China quite differently. That is, SST warming in the Indian Ocean largely contributes to the increase in the amount of summer precipitation over East Asia, which is in contrast to the warming of the western tropical Pacific Ocean. Our further analysis indicates that an altered large-scale atmospheric circulation over the western tropical Pacific contributes to contrasting atmospheric motion over East Asia due to the tropics-East Asia teleconnections, which results in changes in the amount of summer precipitation due to the warming of the Indian and western tropical Pacific Oceans.

  9. Improved Regional Climate Model Simulation of Precipitation by a Dynamical Coupling to a Hydrology Model

    DEFF Research Database (Denmark)

    Larsen, Morten Andreas Dahl; Drews, Martin; Hesselbjerg Christensen, Jens;

    - and river flow as well as land surface-atmosphere fluxes of water (evapotranspiration) and energy - significantly reduces precipitation bias compared to the regional climate model alone. For a six year simulation period (2004 – 2010) covering a 2500 km2 catchment substantial improvements in the......The complexity of precipitation processes makes it difficult for climate models to reliably simulate precipitation, particularly at sub-grid scales, where the important processes are associated with detailed land-atmosphere feedbacks like the vertical circulations driven by latent heat that affect...... convective precipitation systems. As a result climate model simulations let alone future projections of precipitation often exhibit substantial biases. Here we show that the dynamical coupling of a regional climate model to a detailed fully distributed hydrological model - including groundwater-, overland...

  10. Local biomass burning is a dominant cause of the observed precipitation reduction in southern Africa

    Science.gov (United States)

    Hodnebrog, Øivind; Myhre, Gunnar; Forster, Piers M.; Sillmann, Jana; Samset, Bjørn H.

    2016-04-01

    Observations indicate a precipitation decline over large parts of southern Africa since the 1950s. Concurrently, atmospheric concentrations of greenhouse gases and aerosols have increased due to anthropogenic activities. Here we show that local black carbon and organic carbon aerosol emissions from biomass burning activities are a main cause of the observed decline in southern African dry season precipitation over the last century. Near the main biomass burning regions, global and regional modelling indicates precipitation decreases of 20-30%, with large spatial variability. Increasing global CO2 concentrations further contribute to precipitation reductions, somewhat less in magnitude but covering a larger area. Whereas precipitation changes from increased CO2 are driven by large-scale circulation changes, the increase in biomass burning aerosols causes local drying of the atmosphere. This study illustrates that reducing local biomass burning aerosol emissions may be a useful way to mitigate reduced rainfall in the region.

  11. Precipitation products from the hydrology SAF

    Directory of Open Access Journals (Sweden)

    A. Mugnai

    2013-08-01

    Full Text Available The EUMETSAT Satellite Application Facility on Support to Operational Hydrology and Water Management (H-SAF was established by the EUMETSAT Council on 3 July 2005, starting activity on 1 September 2005. The Italian Meteorological Service serves as Leading Entity on behalf of twelve European member countries. H-SAF products include precipitation, soil moisture and snow parameters. Some products are based only on satellite observations, while other products are based on the assimilation of satellite measurements/products into numerical models. In addition to product development and generation, H-SAF includes a product validation program and a hydrological validation program that are coordinated, respectively, by the Italian Department of Civil Protection and by the Polish Institute of Meteorology and Water Management. The National Center of Aeronautical Meteorology and Climatology (CNMCA of the Italian Air Force is responsible for operational product generation and dissemination. In this paper we describe the H-SAF precipitation algorithms and products, which have been developed by the Italian Institute of Atmospheric Sciences and Climate (in collaboration with the international community and by CNMCA during the Development Phase (DP, 2005–2010 and the first Continuous Development and Operations Phase (CDOP-1, 2010–2012. The precipitation products are based on passive microwave measurements obtained from radiometers onboard different sun-synchronous low-Earth-orbiting satellites (especially, the SSM/I and SSMIS radiometers onboard DMSP satellites and the AMSU-A + AMSU-B/MHS radiometer suites onboard EPS-MetOp and NOAA-POES satellites, as well as on combined infrared/passive microwave measurements in which the passive microwave precipitation estimates are used in conjunction with SEVIRI images from the geostationary MSG satellite. Moreover, the H-SAF product generation and dissemination chain and independent product validation activities are

  12. Relations between oxygen stable isotopic ratios in precipitation and relevant meteorological factors in southwest China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The correlations of isotopic ratios in precipitation with temperature, air pressure and humidity at dif- ferent altitudes, in southwest China, are analyzed. There appear marked negative correlations for the δ 18O in precipitation with precipitation amount, vapor pressure and atmospheric precipitable water (PW) at Mengzi, Simao and Tengchong stations on synoptic timescale; the marked negative correlations between the δ 18O in precipitation and the diurnal mean temperature at 400 hPa, 500 hPa, 700 hPa and 850 hPa are different from the temperature effect in middle-high-latitude inland. Moreover, the notable positive correlation between the δ 18O in precipitation and the dew-point deficit △Td at different altitudes is found at the three stations. On annual timescale, the annual precipitation amount weighted mean δ 18O display the negative correlations not only with annual precipitation but also with annual mean temperature at 500 hPa. It can be deduced that, in the years with abnormally strong summer monsoon, more warm and wet air from low-latitude oceans is transported northward along the vapor channel located in southwest China and generates abnormally strong rainfall on the way. Meanwhile, the ab- normally strong condensation process will release more condensed latent heat into atmosphere, and lead to the rise of atmospheric temperature during rainfall, but decline of the δ 18O in precipitation. On the contrary, in the years with abnormally weak summer monsoon, the abnormally weak condensation process will release less condensed latent heat into atmosphere, and lead to the decline of atmos- pheric temperature during rainfall, but increase of the δ 18O in precipitation.

  13. South America Land-Atmosphere Coupling Strength

    Science.gov (United States)

    de Mattos, J. Z.; Goncalves, L.; Herdies, D. L.

    2013-05-01

    This study examines the land-atmosphere coupling strength during summer over subregions of the South America based on simulations made with the Atmospheric Global Circulation Model (AGCM) of the INPE/CPTEC coupled with the simplified simple biosphere model (SsiB). The coupling strength is evaluated by the ability of subsurface soil wetness to affect locally the time series of precipitation. We follow the protocols of the Global Land-Atmosphere Coupling Experiment (GLACE) to measure the strenght of the land-atmosphere coupling. Over South America are found two main regions of strong coupling: 1) the La Plata Basin and 2) the Northeastern of Brazil. Some studies suggest that this regions are hotspot due to evapotranspiration recycling. Additional experiments, with different convective parameterization and with constrains in the surface soilmoisture, in which we isolate the AGCM as the principal source of the sensitivity of precipitation to land surface states were made.

  14. Environmental Radioactivity, Temperature, and Precipitation.

    Science.gov (United States)

    Riland, Carson A.

    1996-01-01

    Reports that environmental radioactivity levels vary with temperature and precipitation and these effects are due to radon. Discusses the measurement of this environmental radioactivity and the theory behind it. (JRH)

  15. The precipitation of vanadium compounds

    International Nuclear Information System (INIS)

    The results of a study on the chemistry of the precipitation process of vanadium compounds in sulfuric media are presented, in order to recover the vanadium contained in the ore from Campo Alegre de Lourdes (Bahia-Brazil). (Author)

  16. Atrial Ectopics Precipitating Atrial Fibrillation

    OpenAIRE

    Johnson Francis

    2015-01-01

    Holter monitor tracing showing blocked atrial ectopics and atrial ectopic precipitating atrial fibrillation is being demonstrated. Initially it was coarse atrial fibrillation, which rapidly degenerated into fine atrial fibrillation.

  17. Ionospheric response to particle precipitation within aurora

    International Nuclear Information System (INIS)

    The aurora is just the visible signature of a large number of processes occurring in a planetary ionosphere as a response to energetic charged particles falling in from the near-empty space far above the planetary atmosphere. This thesis, based on measurements using the EISCAT incoherent scatter radar system in northern Scandinavia, discusses ionospheric response processes and especially a mechanism leading to atmospheric gas escape from a planet. One of the most spectacular events in the high latitude atmosphere on earth are the 'auroral arcs' - dynamic rayed sheets of light. An investigation of the conditions of the ionosphere surrounding auroral arcs shows that strong field-aligned bulk ion outflows appear in the topside ionosphere which account for a large fraction of the escape of atmospheric oxygen from earth. Four different additional ionospheric responses are closely related to this ion outflow; 1. enhanced electron temperatures of several thousand Kelvin above an altitude of about 250 km, 2. enhanced ionization around an altitude of 200 km corresponding to electron precipitation with energies of a few hundred eV, 3. the occurrence of naturally enhanced ion acoustic fluctuations seen in the radar spectrum, most likely produced by an ion-ion two-stream instability, and 4. upward directed field-aligned currents partly carried by the outflowing ions. From these observations, it is suggested that the energy dissipation into the background plasma through Joule heating, the production of a few hundred eV energetic run-away electrons, and strong ion outflows are partly produced by the simultaneous presence of ion acoustic turbulence and field-aligned currents above auroral arcs. (20 refs.) (au)

  18. Global Precipitation Measurement (GPM) implementation

    Science.gov (United States)

    Neeck, Steven P.; Kakar, Ramesh K.; Azarbarzin, Ardeshir A.; Hou, Arthur Y.

    2010-10-01

    The Global Precipitation Measurement (GPM) mission will provide enhanced space-based precipitation measurements with sufficient coverage, spatial resolution, temporal sampling, retrieval accuracy, and microphysical information to advance the understanding of Earth's water and energy cycle and to improve predictions of its climate, weather, and hydrometeorological processes. Such improvements will in turn improve decision support systems in broad societal applications (e.g. water resource management, agriculture, transportation, etc). GPM is a partnership between NASA and the Japan Aerospace Exploration Agency (JAXA), building upon their highly successful partnership on the Tropical Rainfall Measuring Mission (TRMM). The GPM architecture consists of NASA satellites operating in partnership with other earth-observing satellites and instruments to produce global precipitation science data. The current generation of multi-satellite global precipitation products based on microwave/infrared sensors from uncoordinated satellite missions has for its anchor the TRMM precipitation radar and the TRMM Microwave Imager measurements over the tropics and subtropics (+/- 35 degrees latitude), with a mean sampling time of approximately 17 hours. The GPM mission will deploy a spaceborne Core Observatory as a reference standard to unify a space constellation of research and operational microwave sensors aimed at providing uniformly calibrated precipitation measurements globally every 2-4 hours. The Core Observatory measurements will provide, for the first time, quantitative information on precipitation particle size distribution needed for improving the accuracy of precipitation estimates by microwave radiometers and radars. In addition, the GPM will also include a second microwave radiometer and a Tracking and Data Relay Satellite (TDRS) communications subsystem for near real time data relay for a future partner-provided constellation satellite. This second GPM Microwave Imager (GMI

  19. Neptunium_Oxide_Precipitation_Kinetics_AJohnsen

    Energy Technology Data Exchange (ETDEWEB)

    Johnsen, A M; Roberts, K E; Prussin, S G

    2012-06-08

    We evaluate the proposed NpO{sub 2}{sup +}(aq)-NpO{sub 2}(cr) reduction-precipitation system at elevated temperatures to obtain primary information on the effects of temperature, ionic strength, O{sub 2} and CO{sub 2}. Experiments conducted on unfiltered solutions at 10{sup -4} M NpO{sub 2}{sup +}(aq), neutral pH, and 200 C indicated that solution colloids strongly affect precipitation kinetics. Subsequent experiments on filtered solutions at 200, 212, and 225 C showed consistent and distinctive temperature-dependent behavior at reaction times {le} 800 hours. At longer times, the 200 C experiments showed unexpected dissolution of neptunium solids, but experiments at 212 C and 225 C demonstrated quasi steady-state neptunium concentrations of 3 x 10{sup -6} M and 6 x 10{sup -6} M, respectively. Solids from a representative experiment analyzed by X-ray diffraction were consistent with NpO{sub 2}(cr). A 200 C experiment with a NaCl concentration of 0.05 M showed a dramatic increase in the rate of neptunium loss. A 200 C experiment in an argon atmosphere resulted in nearly complete loss of aqueous neptunium. Previously proposed NpO{sub 2}{sup +}(aq)-NpO{sub 2}(cr) reduction-precipitation mechanisms in the literature specified a 1:1 ratio of neptunium loss and H{sup +} production in solution over time. However, all experiments demonstrated ratios of approximately 0.4 to 0.5. Carbonate equilibria can account for only about 40% of this discrepancy, leaving an unexpected deficit in H+ production that suggests that additional chemical processes are occurring.

  20. Irrigation enhances precipitation at the mountains downwind

    Directory of Open Access Journals (Sweden)

    J. Jódar

    2010-05-01

    Full Text Available Atmospheric circulation models predict an irrigation-rainfall feedback. However, actual field evidences are very weak. We present strong field evidence about an increase in rainfall at the mountains located downwind of irrigated zones. We chose two regions, located in semiarid southern Spain, where irrigation started at a well defined date, and we analyzed rainfall statistics before and after the beginning of irrigation. Analyzed statistics include the variation of (1 mean rainfall Δ P, (2 ratio of monthly precipitation to annual precipitation Δ r, and (3 number of months with minimum rainfall episodes Δ Pmin after a transition period from unirrigated to irrigated conditions. All of them show statistically significant increases. Δ P and Δ r show larger and more statistically significant variations in June and July. Their variation is proportional to the mean annual water volume applied in the neighboring upwind irrigation lands. Variations in Δ Pmin are statistically significant in the whole summer. That is, the number of months with some rain displays a relevant increase after irrigation. However, increase in rainfall while statistically significant is distributed over a broad region, so that it is of little relevance from a water resources perspective. The joint increment in Δ P and Δ Pmin after the irrigation transition period denotes a net increase in the number of months having a minimum cumulated precipitation in summer.

  1. Negative corona discharges modelling. Application to the electrostatic precipitation

    International Nuclear Information System (INIS)

    Electrostatic precipitation presents many advantages from the nuclear wastes treatment's point of view. Indeed, this kind of process can capture submicron particles without producing secondary wastes (no filter media) and without pressure looses in the exhaust circuit. The work presented in this thesis concerns the study of negative corona discharges in air at atmospheric pressure occurring in an electrostatic precipitator (ESP) developed by the CEA (Atomic Energy Committee). The aim of this study is to determine how the electrostatic precipitation dedicated phenomena, especially the specific high voltage generator, the gas temperature and the fact that particles are flowing through the gap then collapsing on the electrodes, modify the discharge to improve the efficiency of ESPs. This work is based on a fundamental experimental study of the negative corona discharge and on numerical simulations of this discharge under conditions close to those of the lab scale ESP developed by the CEA. (author)

  2. Variations of gamma radiation spectra during precipitations

    International Nuclear Information System (INIS)

    In the present paper results of prolonging studies of variations of a natural gamma (X-ray) radiation during precipitations registered at cosmic ray station in Apatity are presented. To the present time in the complex installation realizing monitoring of the near ground radiation, the detector is added on the basis of a scintillation crystal by size Ø150×100 mm. The special procedure of working out of the differential energy spectra obtained on the basis of this detector is designed. Due to this it is found, that increases are produced by an additional flux of radiation with the non-regular descending energy spectrum superimposed on a background radiation, having a power law energy spectrum. The clear upper energy limit of the additional radiation, accompanying with precipitations, is observed. It is 1.8-2.0 MeV. Any spectral lines, which could be produced by radionuclides, are not revealed in all researched gamut. It is concluded that these fluxes are produced by energetic charged particles during their passage through the atmosphere, i.e. Bremsstrahlung generation process. Based on the energy balance, the minimum field strength, which can cause a secondary increase, was performed.

  3. What controls deuterium excess in global precipitation?

    Directory of Open Access Journals (Sweden)

    S. Pfahl

    2014-04-01

    Full Text Available The deuterium excess (d of precipitation is widely used in the reconstruction of past climatic changes from ice cores. However, its most common interpretation as moisture source temperature cannot directly be inferred from present-day water isotope observations. Here, we use a new empirical relation between d and near-surface relative humidity (RH together with reanalysis data to globally predict d of surface evaporation from the ocean. The very good quantitative agreement of the predicted hemispherically averaged seasonal cycle with observed d in precipitation indicates that moisture source relative humidity, and not sea surface temperature, is the main driver of d variability on seasonal timescales. Furthermore, we review arguments for an interpretation of long-term palaeoclimatic d changes in terms of moisture source temperature, and we conclude that there remains no sufficient evidence that would justify to neglect the influence of RH on such palaeoclimatic d variations. Hence, we suggest that either the interpretation of d variations in palaeorecords should be adapted to reflect climatic influences on RH during evaporation, in particular atmospheric circulation changes, or new arguments for an interpretation in terms of moisture source temperature will have to be provided based on future research.

  4. Impact of Amazonian deforestation on atmospheric chemistry

    OpenAIRE

    Ganzeveld, L.N.; Lelieveld, J.

    2004-01-01

    A single-column chemistry and climate model has been used to study the impact of deforestation in the Amazon Basin on atmospheric chemistry. Over deforested areas, daytime ozone deposition generally decreases strongly except when surface wetness decreases through reduced precipitation, whereas nocturnal soil deposition increases. The isoprene and soil nitric oxide emissions decrease although nitrogen oxide release to the atmosphere increases due to reduced canopy deposition. Deforestation als...

  5. Auroral ion precipitation at Jupiter: Predictions for Juno

    Science.gov (United States)

    Ozak, N.; Cravens, T. E.; Schultz, D. R.

    2013-08-01

    The spatially localized and highly variable polar cap emissions at Jupiter are part of a poorly understood current system linking the ionosphere and the magnetopause region. Strong X-ray emission has been observed from the polar caps and has been explained by the precipitation of oxygen and sulfur ions of several MeV energy. The present paper presents results of an extended model of the ion precipitation process at Jupiter. Specifically, we add to a previous model a more complete treatment of ionization of the atmosphere, generation of secondary electron fluxes and their escape from the atmosphere, and generation of downward field-aligned currents. Predictions relevant to observations by the upcoming NASA Juno mission are made, namely the existence of escaping electrons with energies from a few eV up to 10 keV, auroral H2 band emission rates of 80 kR, and downward field-aligned currents of at least 2 MA.

  6. Recent changes in precipitation, ITCZ convection and northern tropical circulation over North Africa (1979-2007)

    OpenAIRE

    Fontaine, Bernard; Roucou, Pascal; Gaetani, Marco; Marteau, Romain

    2011-01-01

    This article focuses on some recent changes observed in the Tropics with special emphasis on the African monsoon region using high-resolution gridded precipitation from the Climatic Research Unit (period 1979-2002), outgoing longwave radiation at the top of the atmosphere from the National Oceanic and Atmospheric Administration and atmospheric reanalyses from the Climate Prediction Center (NCEP-DOE2, period 1979-2007). The results show a rainfall increase in North Africa since the mid-90s wit...

  7. Atmospheric thermodynamics

    CERN Document Server

    Iribarne, J V

    1973-01-01

    The thermodynamics of the atmosphere is the subject of several chapters in most textbooks on dynamic meteorology, but there is no work in English to give the subject a specific and more extensive treatment. In writing the present textbook, we have tried to fill this rather remarkable gap in the literature related to atmospheric sciences. Our aim has been to provide students of meteorology with a book that can playa role similar to the textbooks on chemical thermodynamics for the chemists. This implies a previous knowledge of general thermodynamics, such as students acquire in general physics courses; therefore, although the basic principles are reviewed (in the first four chapters), they are only briefly discussed, and emphasis is laid on those topics that will be useful in later chapters, through their application to atmospheric problems. No attempt has been made to introduce the thermodynamics of irreversible processes; on the other hand, consideration of heterogeneous and open homogeneous systems permits a...

  8. Development of precipitator of fluid film type

    International Nuclear Information System (INIS)

    The precipitator of fluid film type is developed for the determination of fuel element cladding failure of water-cooled reactor. It integrates the scrubber, precipitator and detector. The jet of element cooling water automatically circulates carrier gas and the flow water film transfers precipitates onto the surface of centre electrode. Three different types are designed. On the special test loop, the uranium sample pellets of simulating cladding failure is measured. The sensitivity of precipitators, saturated precipitation voltage, incremental speed of signal, speed of driving out precipitates and the contents of the precipitates are determined. The test shows that the precipitators are highly sensitive, reliable, cheap and easy to operate

  9. Comparing the relationship between precipitation and river geochemistry

    Science.gov (United States)

    Epp, A.; Luymes, R.; Bennett, M.; DaSilva, J.; Marsh, S. J.; Gillies, S. L.; Peucker-Ehrenbrink, B.; Voss, B.

    2013-12-01

    The geochemistry of precipitation affects the geochemistry of river water. Ideally, studies of river biogeochemistry should therefore include collection and analyses of dry and wet deposition. The Global Rivers Observatory has studied the Fraser River near Vancouver since the summer of 2009 at roughly bi-weekly resolution. The interpretation of this temporal record of river biogeochemistry, particularly the various sources of solutes, could be improved with a better understanding of atmospheric contributions. In this study precipitation and river water will be analysed from the Fraser River basin for nutrients as well as major and select trace ion concentrations. The nutrients analyzed will include ammonium (NH4), nitrate and nitrate (NO3-NO2), phosphate (PO4) and silicate (SiO4). Major ions include sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), chloride (Cl), and sulfate (SO4). Trace elements may include molybdenum, strontium, barium, uranium, rubidium, manganese and iron. Samples will be collected using the bulk method which collects both wet and dry deposition . Correlating precipitation chemistry with data on wind direction may help elucidate sources of nutrients and major ions. For instance, westerly sources may transport pollution from the City of Vancouver and agricultural lands in the Fraser delta. Such pollutants may increase the acidity of precipitation and imprint the water chemistry with a unique chemical signature . The results of this study will be helpful in correcting Fraser River water data for contributions from atmospheric deposition.

  10. Stratocumulus Precipitation and Entrainment Experiment (SPEE) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, Bruce [Univ. of Miami, Miami, FL (United States); Ghate, Virendra [Argonne National Lab. (ANL), Argonne, IL (United States); CADeddu, Maria [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-06-01

    The scientific focus of this project was to examine precipitation and entrainment processes in marine stratocumulus clouds. The entrainment studies focused on characterizing cloud turbulence at cloud top using Doppler cloud radar observations. The precipitation studies focused on characterizing the precipitation and the macroscopic properties (cloud thickness, and liquid water path) of the clouds. This project will contribute to the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s overall objective of providing the remote-sensing observations needed to improve the representation of key cloud processes in climate models. It will be of direct relevance to the components of ARM dealing with entrainment and precipitation processes in stratiform clouds. Further, the radar observing techniques that will be used in this study were developed using ARM Southern Great Plains (SGP) facility observations under Atmospheric System Research (ASR) support. The observing systems operating automatously from a site located just north of the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) aircraft hangar in Marina, California during the period of 1 May to 4 November 2015 included: 1. Microwave radiometer: ARM Microwave Radiometer, 3-Channel (MWR3C) with channels centered at 23.834, 30, and 89 GHz; supported by Dr. Maria Cadeddu. 2. Cloud Radar: CIRPAS 95 GHz Frequency Modulated Continuous Wave (FMCW) Cloud Radar (Centroid Frequency Chirp Rate [CFCR]); operations overseen by Drs. Ghate and Albrecht. 3. Ceilometer: Vaisala CK-14; operations overseen by Drs. Ghate and Albrecht.

  11. Modelling West African Total Precipitation Depth: A Statistical Approach

    OpenAIRE

    Sovoe, S.

    2015-01-01

    Even though several reports over the past few decades indicate an increasing aridity over West Africa, attempts to establish the controlling factor(s) have not been successful. The traditional belief of the position of the Inter-tropical Convergence Zone (ITCZ) as the predominant factor over the region has been refuted by recent findings. Changes in major atmospheric circulations such as African Easterly Jet (AEJ) and Tropical Easterly Jet (TEJ) are being cited as major precipitation driving ...

  12. Atmospheric Smell

    DEFF Research Database (Denmark)

    Stenslund, Anette

    awareness. Subsequently, visitor interviews revealed how a museum-staged hospital atmosphere of an art installation was directly addressed owing to its smell. Curiously, this observation speaks against prevailing literature portraying smell as the ‘mute sense’, and what is more, the museum display did not...... alter smell curatorially. Rather, smell was gestured through non-olfactory effects and it was put in words metonymically, gesturing a reversibly synaesthetic atmosphere of a hospital. Visitor conversations revealed how smell could be poignantly picked up in situ, yet not until frequenting the museum...

  13. A Global View of Large-Scale Precipitation Variability.

    Science.gov (United States)

    Rasmusson, Eugene M.; Arkin, Phillip A.

    1993-08-01

    Observational studies and model experiments make abundantly clear the need for a global perspective in order to understand the nature and causes of persistent regional precipitation anomalies. Rainfall in the deep tropics is particularly important as a forcing mechanism for the atmosphere's large-scale circulation and climate. Analysis of systematic space-based observations and surface marine data over the past three decades has vastly improved our understanding of tropical convective regimes and their relationship to surface conditions. The characteristics of the annual cycle of tropical convection and its relationship to sea surface temperature field and the general circulation of the tropics are reviewed. The hierarchal nature of tropical precipitation variability on time/space scales ranging from synoptic cloud clusters through the intraseasonal Madden-Julian Oscillation to multiyear El Niño-Southern Oscillation cycle is discussed. Links between tropical convection and extratropical precipitation on time scales ranging from synoptic to multiyear are examined, with emphasis on conditions over the North Pacific-North American sector during winter.Precipitation variability over a number of regions bordering the Atlantic basin are related to Atlantic sector modes of SST and circulation variability. Systematic modes of Atlantic variability and their relationship to regional precipitation variability are described with emphasis on the tropics.Changes in landscape characteristics (vegetative cover, soil moisture, surface roughness), whether natural or human induced, result in changes in the surface radiation balance and the fluxes of heat and moisture. Our current understanding of the role of land surface processes in sustaining or intensifying anomalous precipitation regimes is briefly discussed. Identification of an anthropogenic trend in the presence of decadal-scale natural variations in precipitation is a formidable challenge. Three examples of large

  14. Precipitation regime and stable isotopes at Dome Fuji, East Antarctica

    Science.gov (United States)

    Dittmann, Anna; Schlosser, Elisabeth; Masson-Delmotte, Valérie; Powers, Jordan G.; Manning, Kevin W.; Werner, Martin; Fujita, Koji

    2016-06-01

    A unique set of 1-year precipitation and stable water isotope measurements from the Japanese Antarctic station, Dome Fuji, has been used to study the impact of the synoptic situation and the precipitation origin on the isotopic composition of precipitation on the Antarctic Plateau. The Antarctic Mesoscale Prediction System (AMPS) archive data are used to analyse the synoptic situations that cause precipitation. These situations are investigated and divided into five categories. The most common weather situation during a precipitation event is an upper-level ridge that extends onto the Antarctic Plateau and causes strong northerly advection from the ocean. Most precipitation events are associated with an increase in temperature and wind speed, and a local maximum of δ18O. During the measurement period, 21 synoptically caused precipitation events caused 60 % of the total annual precipitation, whereas the remaining 40 % were predominantly attributed to diamond dust. By combining the synoptic analyses with 5-day back-trajectories, the moisture source regions for precipitation events were estimated. An average source region around a latitude of 55° S was found. The atmospheric conditions in the source region were used as initial conditions for running a Rayleigh-type isotopic model in order to reproduce the measured isotopic composition of fresh snow and to investigate the influence of the precipitation source region on the isotope ratios. The model represents the measured annual cycle of δ18O and the second-order isotopic parameter deuterium excess reasonably well, but yields on average too little fractionation along the transport/cooling path. While simulations with an isotopic general circulation model (GCM) (ECHAM5-wiso) for Dome Fuji are on average closer to the observations, this model cannot reproduce the annual cycle of deuterium excess. In the event-based analysis, no evidence of a correlation of the measured deuterium excess with the latitude of the

  15. A Precipitation Climatology of the Snowy Mountains, Australia

    Science.gov (United States)

    Theobald, Alison; McGowan, Hamish; Speirs, Johanna

    2014-05-01

    The precipitation that falls in the Snowy Mountains region of southeastern Australia provides critical water resources for hydroelectric power generation. Water storages in this region are also a major source of agricultural irrigation, environmental flows, and offer a degree of flood protection for some of the major river systems in Australia. Despite this importance, there remains a knowledge gap regarding the long-term, historic variability of the synoptic weather systems that deliver precipitation to the region. This research aims to increase the understanding of long-term variations in precipitation-bearing weather systems resulting in runoff into the Snowy Mountains catchments and reservoirs, and the way in which these are influenced by large-scale climate drivers. Here we present initial results on the development of a climatology of precipitation-bearing synoptic weather systems (synoptic typology), spanning a period of over 100 years. The synoptic typology is developed from the numerical weather model re-analysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF), in conjunction with regional precipitation and temperature data from a network of private gauges. Given the importance of surface, mid- and upper-air patterns on seasonal precipitation, the synoptic typing will be based on a range of meteorological variables throughout the depth of the troposphere, highlighting the importance of different atmospheric levels on the development and steering of synoptic precipitation bearing systems. The temporal and spatial variability of these synoptic systems, their response to teleconnection forcings and their contribution to inflow generation in the headwater catchments of the Snowy Mountains will be investigated. The resulting climatology will provide new understanding of the drivers of regional-scale precipitation variability at inter- and intra-annual timescales. It will enable greater understanding of how variability in synoptic scale

  16. Characterization of flood and precipitation events in Southwestern Germany and stochastic simulation of extreme precipitation (Project FLORIS-SV)

    Science.gov (United States)

    Florian, Ehmele; Michael, Kunz

    2016-04-01

    Several major flood events occurred in Germany in the past 15-20 years especially in the eastern parts along the rivers Elbe and Danube. Examples include the major floods of 2002 and 2013 with an estimated loss of about 2 billion Euros each. The last major flood events in the State of Baden-Württemberg in southwest Germany occurred in the years 1978 and 1993/1994 along the rivers Rhine and Neckar with an estimated total loss of about 150 million Euros (converted) each. Flood hazard originates from a combination of different meteorological, hydrological and hydraulic processes. Currently there is no defined methodology available for evaluating and quantifying the flood hazard and related risk for larger areas or whole river catchments instead of single gauges. In order to estimate the probable maximum loss for higher return periods (e.g. 200 years, PML200), a stochastic model approach is designed since observational data are limited in time and space. In our approach, precipitation is linearly composed of three elements: background precipitation, orographically-induces precipitation, and a convectively-driven part. We use linear theory of orographic precipitation formation for the stochastic precipitation model (SPM), which is based on fundamental statistics of relevant atmospheric variables. For an adequate number of historic flood events, the corresponding atmospheric conditions and parameters are determined in order to calculate a probability density function (pdf) for each variable. This method involves all theoretically possible scenarios which may not have happened, yet. This work is part of the FLORIS-SV (FLOod RISk Sparkassen Versicherung) project and establishes the first step of a complete modelling chain of the flood risk. On the basis of the generated stochastic precipitation event set, hydrological and hydraulic simulations will be performed to estimate discharge and water level. The resulting stochastic flood event set will be used to quantify the

  17. The transient response of global-mean precipitation to increasing carbon dioxide levels

    International Nuclear Information System (INIS)

    The transient response of global-mean precipitation to an increase in atmospheric carbon dioxide levels of 1% yr-1 is investigated in 13 fully coupled atmosphere-ocean general circulation models (AOGCMs) and compared to a period of stabilization. During the period of stabilization, when carbon dioxide levels are held constant at twice their unperturbed level and the climate left to warm, precipitation increases at a rate of ∼ 2.4% per unit of global-mean surface-air-temperature change in the AOGCMs. However, when carbon dioxide levels are increasing, precipitation increases at a smaller rate of ∼ 1.5% per unit of global-mean surface-air-temperature change. This difference can be understood by decomposing the precipitation response into an increase from the response to the global surface-temperature increase (and the climate feedbacks it induces), and a fast atmospheric response to the carbon dioxide radiative forcing that acts to decrease precipitation. According to the multi-model mean, stabilizing atmospheric levels of carbon dioxide would lead to a greater rate of precipitation change per unit of global surface-temperature change.

  18. Alarming atmospheres

    DEFF Research Database (Denmark)

    Højlund, Marie; Kinch, Sofie

    2014-01-01

    . As a response to this situation, our design artefact, the interactive furniture Kidkit, invites children to become accustomed to the alarming sounds sampled from the ward while they are waiting in the waiting room. Our design acknowledges how atmospheres emerge as temporal negotiations between the...

  19. Deficiencies in quantitative precipitation forecasts. Sensitivity studies using the COSMO model

    Energy Technology Data Exchange (ETDEWEB)

    Dierer, Silke [Federal Office of Meteorology and Climatology, MeteoSwiss, Zurich (Switzerland); Meteotest, Bern (Switzerland); Arpagaus, Marco [Federal Office of Meteorology and Climatology, MeteoSwiss, Zurich (Switzerland); Seifert, Axel [Deutscher Wetterdienst, Offenbach (Germany); Avgoustoglou, Euripides [Hellenic National Meteorological Service, Hellinikon (Greece); Dumitrache, Rodica [National Meteorological Administration, Bucharest (Romania); Grazzini, Federico [Agenzia Regionale per la Protezione Ambientale Emilia Romagna, Bologna (Italy); Mercogliano, Paola [Italian Aerospace Research Center, Capua (Italy); Milelli, Massimo [Agenzia Regionale per la Protezione Ambientale Piemonte, Torino (Italy); Starosta, Katarzyna [Inst. of Meteorology and Water Management, Warsaw (Poland)

    2009-12-15

    The quantitative precipitation forecast (QPF) of the COSMO model, like of other models, reveals some deficiencies. The aim of this study is to investigate which physical and numerical schemes have the strongest impact on QPF and, thus, have the highest potential for improving QPF. Test cases are selected that are meant to reflect typical forecast errors in different countries. The 13 test cases fall into two main groups: overestimation of stratiform precipitation (6 cases) and underestimation of convective precipitation (5 cases). 22 sensitivity experiments predominantly regarding numerical and physical schemes are performed. The area averaged 24 h precipitation sums arc evaluated. The results show that the strongest impact on QPF is caused by changes of the initial atmospheric humidity and by using the Kain-Fritsch/Bechtold convection scheme instead of the Tiedtke scheme. Both sensitivity experiments change the area averaged precipitation in the range of 30-35%. This clearly shows that improved simulation of atmospheric water vapour is of utmost importance to achieve better precipitation forecasts. Significant changes are also caused by using the Runge-Kutta time integration scheme instead of the Leapfrog scheme, by applying a modified warm rain and snow physics scheme or a modified Tiedtke convection scheme. The fore-mentioned changes result in differences of area averaged precipitation of roughly 20%. Only for Greek lest cases, which all have a strong influence from the sea, the heat and moisture exchange between surface and atmosphere is of great importance and can cause changes of up to 20%. (orig.)

  20. Precipitation recycling as a mechanism for ecoclimatological stability through local and non-local interactions

    Science.gov (United States)

    Dominguez, Francina

    This study is the first to analyze the mechanisms that drive precipitation recycling variability at the daily to intraseasonal timescale. A new Dynamic Precipitation Recycling model is developed which, unlike previous models, includes the moisture storage term in the equation of conservation of atmospheric moisture. As shown using scaling analysis, the moisture storage term is non-negligible at small time scales, so the new model enables us to analyze precipitation recycling variability at shorter timescales than traditional models. The daily to intraseasonal analysis enables us to uncover key relationships between recycling and the moisture and energy fluxes. In the second phase of this work, a spatiotemporal analysis of daily precipitation recycling is performed over two regions of North America: the Midwestern United States, and the North American Monsoon System (NAMS) region. These regions were chosen because they present contrasting land-atmosphere interactions. Different physical mechanisms drive precipitation recycling in each region. In the Midwestern United States, evapotranspiration is not significantly affected by soil moisture anomalies, and there is a high recycling ratio during periods of reduced total precipitation. The reason is that, during periods of drier atmospheric conditions, transpiration will continue to provide moisture to the overlying atmosphere and contribute to total rainfall. Consequently, precipitation recycling variability in not driven by changes in evapotranspiration. Precipitable water, sensible heat and moisture fluxes are the main drivers of recycling variability in the Midwest. However, the drier soil moisture conditions over the NAMS region limit evapotranspiration, which will drive recycling variability. In this region, evapotranspiration becomes an important contribution to precipitation after Monsoon onset when total precipitation and evapotranspiration are highest. The precipitation recycling process in the NAMS region

  1. The Global Precipitation Measurement Mission

    Science.gov (United States)

    Jackson, Gail

    2014-05-01

    The Global Precipitation Measurement (GPM) mission's Core satellite, scheduled for launch at the end of February 2014, is well designed estimate precipitation from 0.2 to 110 mm/hr and to detect falling snow. Knowing where and how much rain and snow falls globally is vital to understanding how weather and climate impact both our environment and Earth's water and energy cycles, including effects on agriculture, fresh water availability, and responses to natural disasters. The design of the GPM Core Observatory is an advancement of the Tropical Rainfall Measuring Mission (TRMM)'s highly successful rain-sensing package [3]. The cornerstone of the GPM mission is the deployment of a Core Observatory in a unique 65o non-Sun-synchronous orbit to serve as a physics observatory and a calibration reference to improve precipitation measurements by a constellation of 8 or more dedicated and operational, U.S. and international passive microwave sensors. The Core Observatory will carry a Ku/Ka-band Dual-frequency Precipitation Radar (DPR) and a multi-channel (10-183 GHz) GPM Microwave Radiometer (GMI). The DPR will provide measurements of 3-D precipitation structures and microphysical properties, which are key to achieving a better understanding of precipitation processes and improving retrieval algorithms for passive microwave radiometers. The combined use of DPR and GMI measurements will place greater constraints on possible solutions to radiometer retrievals to improve the accuracy and consistency of precipitation retrievals from all constellation radiometers. Furthermore, since light rain and falling snow account for a significant fraction of precipitation occurrence in middle and high latitudes, the GPM instruments extend the capabilities of the TRMM sensors to detect falling snow, measure light rain, and provide, for the first time, quantitative estimates of microphysical properties of precipitation particles. The GPM Core Observatory was developed and tested at NASA

  2. Dioxin in the atmosphere of Denmark

    Energy Technology Data Exchange (ETDEWEB)

    Vikelsoee, J.; Hovmand, M.F.; Andersen, Helle V.; Bossi, R.; Johansen, Elsebeth; Chrillesen, M.A.

    2006-03-15

    Occurrence and geographical distribution of dioxin was investigated in air and deposition at selected locations in Denmark, three forest sites in the background area, a city site in Copenhagen and a village site. At two sites simultaneously determination of dioxins concentrations in the ambient atmosphere and bulk precipitation were carried out during a period of three years. (au)

  3. Airborne soil organic particles generated by precipitation

    Science.gov (United States)

    Wang, Bingbing; Harder, Tristan H.; Kelly, Stephen T.; Piens, Dominique S.; China, Swarup; Kovarik, Libor; Keiluweit, Marco; Arey, Bruce W.; Gilles, Mary K.; Laskin, Alexander

    2016-06-01

    Airborne organic particles play a critical role in Earth's climate, public health, air quality, and hydrological and carbon cycles. However, sources and formation mechanisms for semi-solid and solid organic particles are poorly understood and typically neglected in atmospheric models. Laboratory evidence suggests that fine particles can be formed from impaction of mineral surfaces by droplets. Here, we use chemical imaging of particles collected following rain events in the Southern Great Plains, Oklahoma, USA and after experimental irrigation to show that raindrop impaction of soils generates solid organic particles. We find that after rain events, sub-micrometre solid particles, with a chemical composition consistent with soil organic matter, contributed up to 60% of atmospheric particles. Our irrigation experiments indicate that intensive water impaction is sufficient to cause ejection of airborne soil organic particles from the soil surface. Chemical imaging and micro-spectroscopy analysis of particle physico-chemical properties suggest that these particles may have important impacts on cloud formation and efficiently absorb solar radiation. We suggest that raindrop-induced formation of solid organic particles from soils may be a widespread phenomenon in ecosystems such as agricultural systems and grasslands where soils are exposed to strong, episodic precipitation events.

  4. Development and application of new methods to retrieve vertical structure of precipitation above the ARM CART sites from MMCR measurements

    Energy Technology Data Exchange (ETDEWEB)

    Matrosov, Sergey

    2010-12-15

    The main objective of this project was to develop, validate and apply remote sensing methods to retrieve vertical profiles of precipitation over the DOE ARM CART sites using currently available remote sensors. While the ARM Program invested very heavily into developments of remote sensing methods and instruments for water vapor and non-precipitating cloud parameter retrievals, precipitation retrievals and studies lagged behind. Precipitation, however, is a crucial part of the water cycle, and without detailed information on rainfall and snowfall, significant improvements in the atmospheric models of different scales (i.e., one of the ARM Program's main goals) is difficult to achieve. Characterization of the vertical atmospheric column above the CART sites is also incomplete without detailed precipitation information, so developments of remote sensing methods for retrievals of parameters in precipitating cloud condition was essential. Providing modelers with retrieval results was also one of the key objectives of this research project.

  5. Diagnostic study of errors in the simulation of tropical continental precipitation in general circulation models

    Directory of Open Access Journals (Sweden)

    J. Srinivasan

    Full Text Available A simple diagnostic model has been used to identify the parameters that induce large errors in the simulation of tropical precipitation in atmospheric General Circulation models (GCM. The GCM that have been considered are those developed by the National Center for Environmental Prediction (NCEP, the National Center for Atmospheric Research (NCAR and the Japanese Meteorological Agency (JMA. These models participated in the phase II of the Atmospheric Model Inter-comparison Project (AMIP II and simulated the climate for the period 1979 to 1995. The root mean-square error in the simulation of precipitation in tropical continents was larger in NCEP and NCAR simulations than in the JMA simulation. The large error in the simulation of precipitation in NCEP was due to errors in the vertical profile of water vapour. The large error in precipitation in NCAR in North Africa was due to an error in net radiation (at the top of the atmosphere. The simple diagnostic model predicts that the moisture converge is a nonlinear function of integrated water vapour. The large error in the interannual variance of rainfall in NCEP over India has been shown to be due to this nonlinearity.

    Key words. Meteorology and atmospheric dynamics (precipitation; tropical meteorology; convective processes

  6. Climate Prediction Center (CPC) 6 to 10 Day Probabilistic Precipitation Outlook for the Contiguous United States and Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Climate Prediction Center (CPC) issues 6 to 10 day probabilistic precipitation outlooks for the United States. The 6-10 day Outlook gives the confidence that a...

  7. Climate Prediction Center (CPC) 8 to 14 Day Probabilistic Precipitation Outlook for the Contiguous United States and Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Climate Prediction Center (CPC) issues 8 to 14 day probabilistic precipitation outlooks for the United States. The 8-14 day Outlook gives the confidence that a...

  8. 24-Hour Forecast of 12 Hour Probability of Precipitation from the National Weather Service's National Digital Forecast Database (NDFD)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Digital Forecast Database (NDFD) contains a seamless mosaic of the National Weather Service's (NWS) digital forecasts of precipitation probabilities....

  9. Projected changes in precipitation extremes linked to temperature over Japan

    Science.gov (United States)

    Nayak, S.; Dairaku, K.; Takayabu, I.; Suzuki-Parker, A.

    2015-12-01

    Recent studies have argued that the extreme precipitation intensities are increasing in many regions across the globe due to atmospheric warming. This argument is based on the principle of Clausius-Clapeyron relationship which states that the atmosphere can hold more moisture in warmer air temperature (~7%/°C). In our study, we have investigated the precipitation extremes linked to temperature in current climate (1981-2000) and their projected changes in late 21st century (2081-2100, RCP4.5) over Japan from multi-model ensemble downscaling experiments by three RCMs (NHRCM, NRAMS, WRF) forced by JRA25 as well as three GCMs (CCSM4, MIROC5, MRI-GCM3). To do this, the precipitation intensities of wet days (defined as ≥ 0.05 mm/d) are stratified to different bins with 1°C temperature interval. We have also identified the occurrences of precipitation extremes in different spell durations and associated peak intensities exceeding various thresholds in two climate periods. We found that extreme precipitation intensities are increased by 5 mm/d in future climate for temperatures above 21°C (Fig. 1). Precipitation extremes of higher percentiles are projected to have larger increase rates in future climate scenarios (3-5%/°C in the current climate and 4-6%/°C in the future climate scenarios). The joint probability distribution of wet hours (≥1mm/h) with various peak intensities under future climate scenarios (RCP4.5) of the late 21st century suggests an increase of long-lived (>10hr) and short-lived (1-2hr) events. On the other hand, a relatively decrease of medium-lived events (3-10hr) are noticed in future climate scenario. The increase of extreme precipitation intensities in future climate is due to the increase in temperature under RCP4.5 (~2°C). Increase in temperature causes more evapotranspiration and subsequently increases the water vapor in the atmosphere.

  10. Rising Mediterranean Sea Surface Temperatures Amplify Extreme Summer Precipitation in Central Europe.

    Science.gov (United States)

    Volosciuk, Claudia; Maraun, Douglas; Semenov, Vladimir A; Tilinina, Natalia; Gulev, Sergey K; Latif, Mojib

    2016-01-01

    The beginning of the 21st century was marked by a number of severe summer floods in Central Europe associated with extreme precipitation (e.g., Elbe 2002, Oder 2010 and Danube 2013). Extratropical storms, known as Vb-cyclones, cause summer extreme precipitation events over Central Europe and can thus lead to such floodings. Vb-cyclones develop over the Mediterranean Sea, which itself strongly warmed during recent decades. Here we investigate the influence of increased Mediterranean Sea surface temperature (SST) on extreme precipitation events in Central Europe. To this end, we carry out atmosphere model simulations forced by average Mediterranean SSTs during 1970-1999 and 2000-2012. Extreme precipitation events occurring on average every 20 summers in the warmer-SST-simulation (2000-2012) amplify along the Vb-cyclone track compared to those in the colder-SST-simulation (1970-1999), on average by 17% in Central Europe. The largest increase is located southeast of maximum precipitation for both simulated heavy events and historical Vb-events. The responsible physical mechanism is increased evaporation from and enhanced atmospheric moisture content over the Mediterranean Sea. The excess in precipitable water is transported from the Mediterranean Sea to Central Europe causing stronger precipitation extremes over that region. Our findings suggest that Mediterranean Sea surface warming amplifies Central European precipitation extremes. PMID:27573802

  11. Evaluation of Precipitation Detection over Various Surfaces from Passive Microwave Imagers and Sounders

    Science.gov (United States)

    Munchak, S. Joseph; Skofronick-Jackson, Gail

    2012-01-01

    During the middle part of this decade a wide variety of passive microwave imagers and sounders will be unified in the Global Precipitation Measurement (GPM) mission to provide a common basis for frequent (3 hr), global precipitation monitoring. The ability of these sensors to detect precipitation by discerning it from non-precipitating background depends upon the channels available and characteristics of the surface and atmosphere. This study quantifies the minimum detectable precipitation rate and fraction of precipitation detected for four representative instruments (TMI, GMI, AMSU-A, and AMSU-B) that will be part of the GPM constellation. Observations for these instruments were constructed from equivalent channels on the SSMIS instrument on DMSP satellites F16 and F17 and matched to precipitation data from NOAA's National Mosaic and QPE (NMQ) during 2009 over the continuous United States. A variational optimal estimation retrieval of non-precipitation surface and atmosphere parameters was used to determine the consistency between the observed brightness temperatures and these parameters, with high cost function values shown to be related to precipitation. The minimum detectable precipitation rate, defined as the lowest rate for which probability of detection exceeds 50%, and the detected fraction of precipitation, are reported for each sensor, surface type (ocean, coast, bare land, snow cover) and precipitation type (rain, mix, snow). The best sensors over ocean and bare land were GMI (0.22 mm/hr minimum threshold and 90% of precipitation detected) and AMSU (0.26 mm/hr minimum threshold and 81% of precipitation detected), respectively. Over coasts (0.74 mm/hr threshold and 12% detected) and snow-covered surfaces (0.44 mm/hr threshold and 23% detected), AMSU again performed best but with much lower detection skill, whereas TMI had no skill over these surfaces. The sounders (particularly over water) benefited from the use of re-analysis data (vs. climatology) to

  12. Timber Mountain Precipitation Monitoring Station

    International Nuclear Information System (INIS)

    A precipitation monitoring station was placed on the west flank of Timber Mountain during the year 2010. It is located in an isolated highland area near the western border of the Nevada National Security Site (NNSS), south of Pahute Mesa. The cost of the equipment, permitting, and installation was provided by the Environmental Monitoring Systems Initiative (EMSI) project. Data collection, analysis, and maintenance of the station during fiscal year 2011 was funded by the U.S. Department of Energy, National Nuclear Security Administration, Nevada Site Office Environmental Restoration, Soils Activity. The station is located near the western headwaters of Forty Mile Wash on the Nevada Test and Training Range (NTTR). Overland flows from precipitation events that occur in the Timber Mountain high elevation area cross several of the contaminated Soils project CAU (Corrective Action Unit) sites located in the Forty Mile Wash watershed. Rain-on-snow events in the early winter and spring around Timber Mountain have contributed to several significant flow events in Forty Mile Wash. The data from the new precipitation gauge at Timber Mountain will provide important information for determining runoff response to precipitation events in this area of the NNSS. Timber Mountain is also a groundwater recharge area, and estimation of recharge from precipitation was important for the EMSI project in determining groundwater flowpaths and designing effective groundwater monitoring for Yucca Mountain. Recharge estimation additionally provides benefit to the Underground Test Area Sub-project analysis of groundwater flow direction and velocity from nuclear test areas on Pahute Mesa. Additionally, this site provides data that has been used during wild fire events and provided a singular monitoring location of the extreme precipitation events during December 2010 (see data section for more details). This letter report provides a summary of the site location, equipment, and data collected in

  13. Magnetic filtration of precipitated magnetite

    International Nuclear Information System (INIS)

    It has been established that treatment of iron-rich alpha contaminated effluent streams by precipitating the iron as ferric floc or magnetite is an effective method of actinide removal. The work reported here shows the effect of four major parameters on the efficiency of the magnetic separation process. These are, the magnetic field strength, the structure of the matrix, the linear velocity of the magnetite suspension during filtration, and the chemical composition of the effluent stream from which magnetite is precipitated. (U.K.)

  14. The characterisation of precipitated magnetites

    International Nuclear Information System (INIS)

    Methods are described for the preparation of magnetite by precipitation from aqueous solutions of iron(II) and iron(III) salts. The magnetites have been characterised by transmission electron microscopy, chemical analysis and X-ray diffraction. Transmission Moessbauer spectroscopy has also been used to characterise precipitated magnetites and a comparison of the spectra has been made with those obtained from nickel ferrite and hydrated ferric oxides. The hydrothermal stability of magnetite at 573 K has also been investigated. This work is relevant to corrosion processes that can occur in the water coolant circuits of nuclear reactors. (author)

  15. Effects of interannual precipitation variability on ecosystem water balance and its consequences for aboveground net primary production

    Science.gov (United States)

    Climate change will result in an increase in the variability of precipitation within and among years as a result of different atmospheric phenomena. For many locations, there will be larger precipitation events interspersed with longer periods of droughts within a year, and more sequences of extreme...

  16. Atmospheric Neutrinos

    CERN Document Server

    Gaisser, Thomas K

    2016-01-01

    In view of the observation by IceCube of high-energy astrophysical neutrinos, it is important to quantify the uncertainty in the background of atmospheric neutrinos. There are two sources of uncertainty, the imperfect knowledge of the spectrum and composition of the primary cosmic rays that produce the neutrinos and the limited understanding of hadron production, including charm, at high energy. This paper is an overview of both aspects.

  17. Atmospheric deposition maps for the Rocky Mountains

    Science.gov (United States)

    Nanus, L.; Campbell, D.H.; Ingersoll, G.P.; Clow, D.W.; Mast, M.A.

    2003-01-01

    Variability in atmospheric deposition across the Rocky Mountains is influenced by elevation, slope, aspect, and precipitation amount and by regional and local sources of air pollution. To improve estimates of deposition in mountainous regions, maps of average annual atmospheric deposition loadings of nitrate, sulfate, and acidity were developed for the Rocky Mountains by using spatial statistics. A parameter-elevation regressions on independent slopes model (PRISM) was incorporated to account for variations in precipitation amount over mountainous regions. Chemical data were obtained from the National Atmospheric Deposition Program/National Trends Network and from annual snowpack surveys conducted by the US Geological Survey and National Park Service, in cooperation with other Federal, State and local agencies. Surface concentration maps were created by ordinary kriging in a geographic information system, using a local trend and mathematical model to estimate the spatial variance. Atmospheric-deposition maps were constructed at 1-km resolution by multiplying surface concentrations from the kriged grid and estimates of precipitation amount from the PRISM model. Maps indicate an increasing spatial trend in concentration and deposition of the modeled constituents, particularly nitrate and sulfate, from north to south throughout the Rocky Mountains and identify hot-spots of atmospheric deposition that result from combined local and regional sources of air pollution. Highest nitrate (2.5-3.0kg/ha N) and sulfate (10.0-12.0kg/ha SO4) deposition is found in northern Colorado.

  18. Electrostatic purification of uranium mine stope atmospheres

    International Nuclear Information System (INIS)

    Electrostatic precipitators have been and are currently being used to reduce levels of radioactive aerosols in uranium mine stope atmospheres. Historically, while the electrostatic precipitators have been reported to be successful in reducing levels of radioactive aerosols many practical problems have been encountered with their use in the underground mine environment. Electrical short circuiting appears to have been the major problem with the use of precipitators in humid underground environments. On the basis of literature reviewed for this study it seems that the problems encountered in the past can be overcome. The most likely use of a precipitator in an underground uranium mine is to treat some or all of the air immediately upstream of a work station. The possible locations and uses of a precipitator would vary from work station to work station and from mine to mine. The desirability and cost of using elctrostatic precipitators to purify the air entering a work station are application specific. SENES Consultants therefore is not recommending for or against the use of electrostatic precipitators in underground uranium mines. The information provided in this report can be used however to assist in such determinations. 72 refs

  19. Influence of precipitating systems on upper Indian Ocean stability during DYNAMO

    Science.gov (United States)

    Thompson, E. J.; Rutledge, S. A.; Moum, J. N.; Fairall, C. W.

    2014-12-01

    The 2011-2012 Dynamics of the Madden-Julian Oscillation (DYNAMO) field campaign produced collocated radar, lidar, ocean, and surface flux datasets at the Revelle research ship to study air-sea interactions related to MJO initiation in the central Indian Ocean. These data have been used to identify precipitation and atmospheric cold pool events at the ship, which appear to contribute different amounts of heat momentum, and salinity into the upper ocean. This study examines how the sequence of radar-indicated convective and stratiform precipitation elements, including their wind stress, gustiness, and rain, affect the erosion or buildup of upper ocean stability. Vertical gradients of potential density, potential temperature, and salinity as well as the resulting mixed layer depth and buoyancy flux quantify how precipitation influences the upper ocean throughout each precipitation and atmospheric cold pool event, the diurnal cycle, and two MJOs observed during DYNAMO.

  20. Mechanisms of Antarctic net precipitation climate change signals

    Science.gov (United States)

    Grieger, Jens; Leckebusch, Gregor C.; Ulbrich, Uwe

    2015-04-01

    This study investigates mechanisms leading to climate change signals of Antarctic net precipitation (E-P) simulated by three members of one CMIP3 coupled atmosphere-ocean general circulation model (AOGCM). Net precipitation is calculated with the divergence of the vertically integrated moisture flux. Generally, moisture flux changes are dominated by increased humidity in the atmosphere due to temperature increase in the future climate projections. This contribution presents an approach to distinguish between thermodynamical and dynamical influences on moisture flux. A physical interpretation of the changing flux signal due to dynamics is given by decomposing atmospheric waves into different length scales and temporal variations. Climate change of moisture transport is compared with fluctuations of geopotential height fields as well as climate signals of extra-tropical cyclones. Synoptic length scale moisture flux variability with temporal variations between 2.5 and 8 days can be assigned to the SH stormtrack, which shows a distinctive poleward shift in the future projection. This signal can also be found for extra-tropical cyclones, whereas changing wave activity can be better understood if strong cyclones separately are taken into account, which intensify especially on the Eastern Hemisphere. Changing moisture transport towards Antarctica leads to climate change signals of net precipitation inside a spherical cap around the continent. Generally, an increasing signal of net precipitation can be found whereas the dynamical part decreases. This is due to the low variability component of synoptic scale waves, which show a decreasing climate change signal, especially off-coast of West Antarctica. This is discussed to be connected to changing variability of the Amundsen-Bellingshausen Sea Low.

  1. Surface radiation governs precipitation responses in transient and equilibrium climates

    Science.gov (United States)

    Sun, Shanshan; Moyer, Elisabeth

    2014-05-01

    Changes in radiative forcing are important not only for their impact on the Earth's temperature but also for their impact on the hydrological cycle. We show that model predictions of an amplified hydrological cycle under higher-CO2 conditions are well explained by changes in the surface energy budget: increased latent heat export largely balances increased downwelling longwave radiation, primarily due to increased humidity in a warmer atmosphere (see also Wild and Liepert 2010). We demonstrate that similar fundamental radiative adjustments govern global precipitation evolution across models, using twenty different GCMs in the Coupled Model Intercomparison Project phase 5 (CMIP5), purpose-run simulations with a fully-coupled GCM (CCSM3), and a simple one-column climate model (CliMT) with no cloud feedbacks but full representations of radiation, convection, turbulence, and surface ocean-atmosphere interaction. Physically understandable surface energy balance changes explain precipitation evolution in both equilibrium and transient climates (the well-documented 'fast' and 'slow' responses), in cases with different forcing agents (solar insolation and CO2), and in geo-engineering simulations where reduced shortwave forcing compensates for increased longwave opacity. We show that the enhancement in precipitation after an increase in radiative forcing is primarily due to the radiative effects of increased water vapor, which in turn produces the similarity in precipitation evolution in solar- and CO2-forced climates. We also show that differences in precipitation evolution between GCMs are due largely to differences in model shortwave feedbacks. The results of this study suggest that changes in the Earth's hydrological cycle under climate change can best be monitored and understood with surface measurements of longwave and shortwave fluxes, especially in the tropics and subtropics that account for the majority of the global moisture supply. References Wild, M. and B

  2. Precipitation kinetics of a continuous precipitator, with application to the precipitation of ammonium polyuranate

    International Nuclear Information System (INIS)

    A mathematical model describing the kinetics of continuous precipitation was developed which accounts for crystal nucleation, crystal growth, primary coagulation, and secondary coagulation. Population density distributions, average particle sizes, dominant particle sizes, and suspension density fractions of the crystallites, primary agglomerates, and secondary agglomerates leaving the continuous precipitator can be determined. This kinetic model was applied to the continuous precipitation of ammonium polyuranate, which consists of: (1) elementary crystals, (2) clusters or primary coagulated particles, and (3) agglomerates or secondary coagulated particles. The crystallites are thin, submicron, hexagonal platelets. The clusters had an upper size limit of about 7 μ in diameter and contained numerous small voids (less than 0.3 μm) due to the packing of the crystallites. The agglomerates had an upper size limit of about 40 μm in diameter and contained large voids (approximately 1 μm). The particle size distribution and particle structure of the ammonium polyuranate precipitate can be controlled through proper regulation of the precipitation conditions. The ratio of clusters to agglomerates can be best controlled through the uranium concentration, and the cohesiveness or internal bonding strength of the particles can be controlled with the ammonium to uranium reacting feed mole ratio. These two conditions, in conjunction with the residence time, will determine the nucleation rates, growth rates, and size distributions of the particles leaving the continuous precipitator. With proper control of these physical particle characteristics, the use of pore formers, ball-milling, and powder blending can probably be eliminated from the nuclear fuel fabrication process, substantially reducing the cost

  3. Classroom Exercises Utilizing Precipitation Data.

    Science.gov (United States)

    Kohler, Fred

    Precipitation data for Macomb (Illinois) for the period 1912-1981 were the bases for developing classroom exercises that offered college students experience in collecting such data. After students collected the data, they reduced them to manageable proportions, and then examined average long-term relations which may have emerged among yearly,…

  4. Extreme precipitation: Increases all round

    Science.gov (United States)

    Ingram, William

    2016-05-01

    Globally, extreme rainfall is expected to increase with warming, but regional changes over land have been less certain. Now research shows that this intense precipitation has increased across both the wetter and the drier parts of the continents, and will continue to do so as global warming continues.

  5. Electrostatic Precipitator (ESP) TRAINING MANUAL

    Science.gov (United States)

    The manual assists engineers in using a computer program, the ESPVI 4.0W, that models all elements of an electrostatic precipitator (ESP). The program is a product of the Electric Power Research Institute and runs in the Windows environment. Once an ESP is accurately modeled, the...

  6. Recent Progresses in Atmospheric Remote Sensing Research in China-- Chinese National Report on Atmospheric Remote Sensing Research in China during 1999-2003

    Institute of Scientific and Technical Information of China (English)

    邱金桓; 陈洪滨

    2004-01-01

    Progresses of atmospheric remote sensing research in China during 1999-2003 are summarily introduced.This research includes: (1) microwave remote sensing of the atmosphere; (2) Lidar remote sensing; (3)remote sensing of aerosol optical properties; and (4) other research related to atmospheric remote sensing,including GPS remote sensing of precipitable water vapor and radiation model development.

  7. Conditional Generation of Monthly Precipitation

    Science.gov (United States)

    Kim, U.; Kaluarachchi, J. J.

    2006-12-01

    Monthly precipitation models can be used in basin-wide modeling to develop long-term strategies for water resources planning and management and to estimate the change of water yield due to climate change. Such precipitation models are especially important for effective management of river basins in developing countries such as the upper Blue Nile River basin of Ethiopia where the water resource utilization is limited. Many studies have been previously performed to preserve historical temporal and spatial structures when generating precipitation series. The main focus of those studies was to preserve the historical statistics. Other important factors to be considered are transition and spatial correlations. A few recent studies attempted to preserve transition as well as the statistics of historical record. These studies provided satisfactory results while showing the difficulty and complexity of computations in their methods. The conditional generation method (CGM) that can preserve both historical temporal and spatial structures is presented in this study. Because the CGM is driven from the historical conditional probabilities occurring given amounts of precipitation between two successive months or two stations, it is computationally simple and reliable, i.e., parameterization, inverse matrix, or optimum band width is not required. The CGM was applied to reproducing the precipitation pattern of the upper Blue Nile River basin in Ethiopia using monthly precipitation data of 10 stations to demonstrate its applicability. Comparing to the method of inverse transformation of cumulative distribution functions of the gamma distribution and nonparametric kernel estimator with variable band width selected from the goodness-of-fit tests, the CGM showed improved performance, especially in representing the transition characteristics. The CGM also generated the historical spatial correlations between the stations with acceptable accuracy. The results suggested that the CGM

  8. The Effects of Great Plains Irrigation on the Surface Energy Balance, Regional Circulation, and Precipitation

    OpenAIRE

    David B. Huber; Mechem, David B.; Nathaniel A. Brunsell

    2014-01-01

    Irrigation provides a needed source of water in regions of low precipitation. Adding water to a region that would otherwise see little natural precipitation alters the partitioning of surface energy fluxes, the evolution of the planetary boundary layer, and the atmospheric transport of water vapor. The effects of irrigation are investigated in this paper through the employment of the Advanced Research (ARW) Weather Research and Forecasting Model (WRF) using a pair of simulations representing ...

  9. Monitoring changes in precipitation and radiative energy using satellite data and climate models

    OpenAIRE

    Allan, R. P.; John, V. O.

    2009-01-01

    Current changes in the tropical hydrological cycle, including water vapour and precipitation, are presented over the period 1979-2008 based on a diverse suite of observational datasets and atmosphere-only climate models. Models capture the observed variability in tropical moisture while reanalyses cannot. Observed variability in precipitation is highly dependent upon the satellite instruments employed and only cursory agreement with model simulations, primarily relating to the ...

  10. An energetic perspective on the regional response of precipitation to climate change

    Science.gov (United States)

    Muller, C. J.; O'Gorman, P. A.

    2011-08-01

    Understanding and predicting the response of the hydrological cycle to climate change is a major challenge with important societal implications. Much progress has been made in understanding the response of global average precipitation by considering the energy balances of the atmosphere and the surface. This energetic perspective reveals that changes in temperature, greenhouse gases, aerosols, solar forcing and cloud feedbacks can all affect the global average rate of precipitation. Local precipitation changes have conventionally been analysed using the water vapour budget, but here we show that the energetic approach can be extended to local changes in precipitation by including changes in horizontal energy transport. In simulations of twenty-first century climate change, this energy transport accounts for much of the spatial variability in precipitation change. We show that changes in radiative and surface sensible heat fluxes are a guide to the local precipitation response over land and at large scales, but not at small scales over the ocean, where cloud and water vapour radiative feedbacks dampen the response. The energetic approach described here helps bridge the gap between our understanding of global and regional precipitation changes. It could be applied to better understand the response of regional precipitation to different radiative forcings, including geo-engineering schemes, as well as to understand the differences between the fast and slow responses of regional precipitation to such forcings.

  11. Variation and future trends in precipitation over summer and autumn across the Yunnan region

    Science.gov (United States)

    Xiao, Ziniu; Zhou, Xiuhua; Yang, Ping; Liu, Hua

    2016-09-01

    This study analyzed the changes in precipitation over summer and autumn across the Yunnan region of China, and undertook a composite analysis of the atmospheric circulations in the troposphere, which included an analysis of the interannual and interdecadal variations. This paper examines in detail the circulation backgrounds of the wet and dry periods in summer and autumn and their correlations with the sea surface temperature. The results indicated that the summer and autumn precipitation across Yunnan has significantly decreased over the past 50 years. Furthermore, since the beginning of the century, the summer and autumn precipitation cycle has been in a low precipitation phase. The overlap of two extremely low rain phases has caused frequent droughts in the region. In addition, the atmospheric circulation fields during these wet and dry periods are very different. These are mainly shown as a meridional wind anomaly in eastern China in the low atmosphere, as a cross-equatorial airflow anomaly, a tropical zonal wind anomaly over the Indian Ocean, and as a related South Asia High and Western Pacific Subtropical High. Further analysis suggested that the SST over the Indian Ocean and the Pacific warm pool critically affect the anomalous summer and autumn precipitation over Yunnan by impacting the monsoon circulations. Future projections for greenhouse gas warming suggest a potential anomalous circulation background between 2010 and 2020 which may result in less precipitation during the wet season or even drought events across the Yunnan region.

  12. Radiative impact of mineral dust on monsoon precipitation variability over West Africa

    Directory of Open Access Journals (Sweden)

    C. Zhao

    2010-11-01

    Full Text Available The radiative forcing of dust and its impact on precipitation over the West Africa monsoon (WAM region is simulated using a coupled meteorology and aerosol/chemistry model (WRF-Chem. During the monsoon season, dust is a dominant contributor to aerosol optical depth (AOD over West Africa. In the control simulation, on 24-h domain average, dust has a cooling effect (−6.11 W/m2 at the surface, a warming effect (6.94 W/m2 in the atmosphere, and a relatively small TOA forcing (0.83 W/m2. Dust modifies the surface energy budget and atmospheric diabatic heating and hence causes lower atmospheric cooling in the daytime but warming in the nighttime. As a result, atmospheric stability is increased in the daytime and reduced in the nighttime, leading to a reduction of late afternoon precipitation by up to 0.14 mm/h (25% and an increase of nocturnal and early morning precipitation by up to 0.04 mm/h (45% over the WAM region. Dust-induced reduction of diurnal precipitation variation improves the simulated diurnal cycle of precipitation when compared to measurements. However, daily precipitation is only changed by a relatively small amount (−0.17 mm/day or −4%. The dust-induced change of WAM precipitation is not sensitive to interannual monsoon variability. On the other hand, sensitivity simulations show that, from weaker to stronger absorbing dust representing the uncertainty in dust solar absorptivity, dust longwave warming effect in the nighttime surpasses its shortwave cooling effect in the daytime at the surface, leading to a less stable atmosphere associated with more convective precipitation in the nighttime. As a result, the dust-induced change of daily WAM precipitation varies from a significant reduction of −0.52 mm/day (−12%, weaker absorbing dust to a small increase of 0.03 mm/day (1%, stronger absorbing dust. This variation originates from the competition between dust impact on daytime and nighttime

  13. Global Precipitation Measurement (GPM) Mission: Overview and Status

    Science.gov (United States)

    Hou, Arthur Y.

    2012-01-01

    (SAPHIR) on the French-Indian MeghaTropiques satellite, (4) the Microwave Humidity Sounder (MHS) on the National Oceanic and Atmospheric Administration (NOAA)-19, (5) MHS instruments on MetOp satellites launched by the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT), (6) the Advanced Technology Microwave Sounder (ATMS) on the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project (NPP), and (7) ATMS instruments on the NOAA-NASA Joint Polar Satellite System (JPSS) satellites. Data from Chinese and Russian microwave radiometers may also become available through international collaboration under the auspices of the Committee on Earth Observation Satellites (CEOS) and Group on Earth Observations (GEO). The current generation of global rainfall products combines observations from a network of uncoordinated satellite missions using a variety of merging techniques. GPM will provide "next-generation" precipitation products characterized by: (1) more accurate instantaneous precipitation estimate (especially for light rain and cold-season solid precipitation), (2) intercalibrated microwave brightness temperatures from constellation radiometers within a consistent framework, and (3) unified precipitation retrievals from constellation radiometers using a common a priori hydrometeor database constrained by combined radar/radiometer measurements provided by the GPM Core Observatory. GPM is a science mission with integrated applications goals. GPM will provide a key measurement to improve understanding of global water cycle variability and freshwater availability in a changing climate. The DPR and GMI measurements will offer insights into 3-dimensional structures of hurricanes and midlatitude storms, microphysical properties of precipitating particles, and latent heat associated with precipitation processes. The GPM mission will also make data available in near realtime (within 3 hours of observations

  14. Understanding the Role of Reservoir Size on Probable Maximum Precipitation

    Science.gov (United States)

    Woldemichael, A. T.; Hossain, F.

    2011-12-01

    This study addresses the question 'Does surface area of an artificial reservoir matter in the estimation of probable maximum precipitation (PMP) for an impounded basin?' The motivation of the study was based on the notion that the stationarity assumption that is implicit in the PMP for dam design can be undermined in the post-dam era due to an enhancement of extreme precipitation patterns by an artificial reservoir. In addition, the study lays the foundation for use of regional atmospheric models as one way to perform life cycle assessment for planned or existing dams to formulate best management practices. The American River Watershed (ARW) with the Folsom dam at the confluence of the American River was selected as the study region and the Dec-Jan 1996-97 storm event was selected for the study period. The numerical atmospheric model used for the study was the Regional Atmospheric Modeling System (RAMS). First, the numerical modeling system, RAMS, was calibrated and validated with selected station and spatially interpolated precipitation data. Best combinations of parameterization schemes in RAMS were accordingly selected. Second, to mimic the standard method of PMP estimation by moisture maximization technique, relative humidity terms in the model were raised to 100% from ground up to the 500mb level. The obtained model-based maximum 72-hr precipitation values were named extreme precipitation (EP) as a distinction from the PMPs obtained by the standard methods. Third, six hypothetical reservoir size scenarios ranging from no-dam (all-dry) to the reservoir submerging half of basin were established to test the influence of reservoir size variation on EP. For the case of the ARW, our study clearly demonstrated that the assumption of stationarity that is implicit the traditional estimation of PMP can be rendered invalid to a large part due to the very presence of the artificial reservoir. Cloud tracking procedures performed on the basin also give indication of the

  15. Electrodynamical Coupling of Earth's Atmosphere and Ionosphere: An Overview

    Directory of Open Access Journals (Sweden)

    A. K. Singh

    2011-01-01

    Full Text Available Electrical processes occurring in the atmosphere couple the atmosphere and ionosphere, because both DC and AC effects operate at the speed of light. The electrostatic and electromagnetic field changes in global electric circuit arise from thunderstorm, lightning discharges, and optical emissions in the mesosphere. The precipitation of magnetospheric electrons affects higher latitudes. The radioactive elements emitted during the earthquakes affect electron density and conductivity in the lower atmosphere. In the present paper, we have briefly reviewed our present understanding of how these events play a key role in energy transfer from the lower atmosphere to the ionosphere, which ultimately results in the Earth's atmosphere-ionosphere coupling.

  16. Mass Transfer and Kinetics Study of Heterogeneous Semi-Batch Precipitation of Magnesium Carbonate

    DEFF Research Database (Denmark)

    Han, B.; Qu, H. Y.; Niemi, H.;

    2014-01-01

    Precipitation kinetics and mass transfer of magnesium carbonate (MgCO3) hydrates from a reaction of magnesium hydroxide (Mg(OH)(2)) and CO2 were analyzed. The effect of CO2 flow rate and mixing intensity on precipitation was investigated under ambient temperature and atmospheric pressure. Raman...... spectroscopy was used to determine the composition of the solids during semi-batch crystallization. The obtained spectra revealed the dissolution of Mg(OH)(2) and the formation of MgCO3. The precipitation rate increased with higher gas flow rate. The rotation speed of the stirrer had a significant effect on...... the dissolution of Mg(OH)(2). In the researched system, the main driver of the precipitation kinetics was the mass transfer of CO2. Nesquehonite (MgCO3 center dot 3H(2)O), as needle-like crystals, was precipitated as the main product. Raman spectroscopy can serve as a potential tool to monitor the...

  17. Longitude and temporal variations of energetic electron precipitation near the trapping boundary

    International Nuclear Information System (INIS)

    Electron precipitation occurring at latitudes near the midnight trapping boundary was measured remotely with a satellite-borne x ray imager (>21 keV). This investigation has demonstrated for the first time the repetitive mapping of precipitation at the trapping boundary with x rays. The satellite spin motion (5.5 second period) provided repeated scans of each scene during a single pass of the satellite. When the in situ electron precipitation, measured directly with a spectrometer (>68 keV) on the same satellite, was limited to a narrow region at the trapping boundary the precipitation inferred from the x rays was generally fairly uniform over a median longitude interval of at least 45 degree. Significant increases at certain longitudes were sometimes observed. The widespread arc patterns of the precipitation have important implications for both understanding the nature of the responsible loss mechanisms and for assessing the atmospheric effects

  18. The sensitivity of precipitation simulations to the soot aerosol presence

    Science.gov (United States)

    Palamarchuk, Iuliia; Ivanov, Sergiy; Mahura, Alexander; Ruban, Igor

    2016-04-01

    The role of aerosols in nonlinear feedbacks on atmospheric processes is in a focus of many researches. Particularly, the importance of black carbon particles for evolution of physical weather including precipitation formation and release is investigated by numerical modelling as well as observation networks. However, certain discrepancies between results obtained by different methods are remained. The increasing of complexity in numerical weather modelling systems leads to enlarging a volume of output data and promises to reveal new aspects in complexity of interactions and feedbacks. The Harmonie-38h1.2 model with the AROME physical package is used to study changes in precipitation life-cycle under black carbon polluted conditions. A model configuration includes a radar data assimilation procedure on a high resolution domain covering the Scandinavia region. Model results show that precipitation rate and distribution as well as other variables of atmospheric dynamics and physics over the domain are sensitive to aerosol concentrations. The attention should also be paid to numerical aspects, such as a list of observation types involved in assimilation. The use of high resolution radar information allows to include mesoscale features in initial conditions and to decrease the growth rate of a model error with the lead time.

  19. Precipitation of radiation belt electrons by man-made waves A comparison between theory and measurement

    Science.gov (United States)

    Inan, U. S.; Chang, H. C.; Helliwell, R. A.; Imhof, W. L.; Reagan, J. B.; Walt, M.

    1985-01-01

    The temporal and spectral shape and the absolute flux level of particle pulses precipitated by a VLF transmitter are examined from a theoretical point of view. A test-particle model of the gyroresonant wave-particle interaction is applied to the parameters of the observed cases for calculating the precipitation characteristics. The temporal shapes of the precipitation pulses are found to be controlled (1) by the pitch angle dependence of the particle distribution near the edge of the loss cone and (2) by the multiple interaction of the particles with the waves due to significant atmospheric backscatter.

  20. Stochastic convective parameterization improving the simulation of tropical precipitation variability in the NCAR CAM5

    Science.gov (United States)

    Wang, Yong; Zhang, Guang J.; Craig, George C.

    2016-06-01

    The Plant-Craig (PC) stochastic convective parameterization scheme is implemented into the National Center for Atmospheric Research Community Atmosphere Model version 5 (CAM5) to couple with the Zhang-McFarlane deterministic convection scheme. To evaluate its impact on tropical precipitation simulation, two experiments are conducted: one with the standard CAM5 and the other with the stochastic scheme incorporated. Results show that the PC stochastic parameterization decreases the frequency of weak precipitation and increases the frequency of strong precipitation, resulting in better agreement with observations. The most striking improvement is in the probability distribution function (PDF) of precipitation intensity, with the well-known too-much-drizzle problem in CAM5 largely eliminated. In the global tropical belt, the precipitation intensity PDF from the simulation agrees remarkably well with that of Tropical Rainfall Measuring Mission observations. The stochastic scheme also yields a similar magnitude of intraseasonal variability of precipitation to observations and improves the simulation of the eastward propagating intraseasonal signals of precipitation and zonal wind.

  1. CLIMATOLOGICAL VARIATION FEATURES OF TYPHOON PRECIPITATION INFLUENCING FUJIAN FOR THE PAST 46 YEARS

    Institute of Scientific and Technical Information of China (English)

    LIN Xiao-hong; REN Fu-min; LIU Ai-ming; HUANG Zhi-gang; LIAO Kuo

    2008-01-01

    The results of an analysis of the temporal and spatial distribution of typhoon precipitation influencing Fujian from 1960 to 2005 show that typhoon precipitation in Fujian province occurs from May to November, with the most in August. There has been a decreasing trend since 1960. Typhoon precipitation gradually decreases from the coastal region to the northwestern mainland of Fujian and the maximum typhoon precipitation occurs in the northeast and the south of Fujian. Typhoon torrential rain is one of the extreme rainfall events in Fujian. High frequencies of typhoon torrential rain occur in the coastal and southwest regions of the province. With the impact of Fujian's terrain, typhoon precipitation occurs more easily to the east of the mountains than to the west. Atmospheric circulation at 500 hPa over Asia and sea surface temperature anomalies of the equatorial eastern Pacific are analyzed, with the finding that they are closely connected with the anomaly of typhoon precipitation influencing Fujian, possibly mainly by modulating the northbound track of typhoons via changing the atmosphere circulation to lead to the anomaly of typhoon precipitation over the province

  2. Future Projections of Precipitation Characteristics in East Asia Simulated by the MRI CGCM2

    Institute of Scientific and Technical Information of China (English)

    Akio KITOH; Masahiro HOSAKA; Yukimasa ADACHI; Kenji KAMIGUCHI

    2005-01-01

    Projected changes in precipitation characteristics around the mid-21st century and end-of-the-century are analyzed using the daily precipitation output of the 3-member ensemble Meteorological Research Institute global ocean-atmosphere coupled general circulation model (MRI-CGCM2) simulations under the Special Report on Emissions Scenarios (SRES) A2 and B2 scenarios. It is found that both the frequency and intensity increase in about 40% of the globe, while both the frequency and intensity decrease in about 20% of the globe. These numbers differ only a few percent from decade to decade of the 21st century and between the A2 and B2 scenarios. Over the rest of the globe (about one third), the precipitation frequency decreases but its intensity increases, suggesting a shift of precipitation distribution toward more intense events by global warming. South China is such a region where the summertime wet-day frequency decreases but the precipitation intensity increases. This is related to increased atmospheric moisture content due to global warming and an intensified and more westwardly extended North Pacific subtropical anticyclone,which may be related with an El Ni(n)o-like mean sea surface temperature change. On the other hand, a decrease in summer precipitation is noted in North China, thus augmenting a south-to-north precipit ation contrast more in the future.

  3. Spatial and altitudinal variation of precipitation and the correction of gridded precipitation datasets for the Upper Indus Basin and the Hindukush-Karakoram-Himalaya

    Science.gov (United States)

    Khan, Asif; Richards, Keith S.; Parker, Geoffrey T.; McRobie, Allan; Booij, Martijn J.; Duan, Zheng; Naz, Bibi S.; Lee, Junhak; Khan, Mujahid

    2015-04-01

    Precise and accurate precipitation data (of both snow and rain) are a vital input for hydrological modeling, climatic studies and glacier mass balance analysis. This study investigates the accuracy of eight widely used gridded datasets, based on mass balance assessments, for the Upper Indus Basin (UIB) in the Himalayas-Karakoram-Hindukush (HKH) mountain region. The eight datasets are: 1) Global Precipitation Climatology Project (GPCP) v 2.2, 2) Climate Prediction Centre (CPC) Merged Analysis of Precipitation (CMAP), 3) National Centers for Environmental Prediction (NCEP) / National Center for Atmospheric Research (NCAR), 4) Global Precipitation Climatology Centre (GPCC), 5) Climatic Research Unit (CRU) v 3.2.2, 6) Asian Precipitation Highly Resolved Observational Data Integration Towards Evaluation of Water Resources (APHRODITE), 7) Tropical Rainfall Measuring Mission (TRMM) 3B33 v 7, and 8) European Reanalysis (ERA) interim data. Precipitation derived from these datasets has been compared with the sum of flow, MODIS ETact (Actual Evapo-transpiration), and glacier imbalance contribution to flows. All these datasets significantly underestimate precipitation, being 40-80% less than the measured flows, except for the NCEP/NCAR and ERA interim datasets, which only slightly underestimate precipitation. This is the case for almost all watersheds in the UIB, particularly the Gilgit, Hunza, Shigar and Astore watersheds. To provide alternative, more physically-reasonable precipitation estimates, annual and seasonal (October-May and June-September) precipitation values have been derived for the entire UIB using multiple regressions relating precipitation for 46 climate stations to the local altitude, slope, aspect, latitude and longitude. The results are distributed across the whole basin on a 1km grid, with an estimated uncertainty of 5-10%. The spatial pattern shows good agreement with the Randolph Glacier Inventory (RGI) v 3.2 data, and with previous local studies that

  4. The effects of mineral dust particles, aerosol regeneration and ice nucleation parameterizations on clouds and precipitation

    Directory of Open Access Journals (Sweden)

    A. Teller

    2012-03-01

    Full Text Available This study focuses on the effects of aerosol particles on the formation of convective clouds and precipitation in the Eastern Mediterranean sea with a special emphasis on the role of mineral dust particles in these processes. We used a new detailed numerical cloud microphysics scheme that has been implemented in the Weather Research and Forecast (WRF model in order to study aerosol-cloud interaction in 3-D configuration based on realistic meteorological data. Using a number of case studies we tested the contribution of mineral dust particles and different ice nucleation parameterizations to precipitation development. In this study we also investigated the importance of recycled (regenerated aerosols that had been released to the atmosphere following the evaporation of cloud droplets.

    The results showed that increased aerosol concentration due to the presence of mineral dust enhanced the formation of ice crystals. The dynamic evolution of the cloud system sets the time periods and regions in which heavy or light precipitation occurred in the domain. The precipitation rate, the time and duration of precipitation were affected by the aerosol properties only at small area scales (with areas of about 20 km2. Changes of the ice nucleation scheme from ice supersaturation dependent parameterization to a recent approach of aerosol concentration and temperature dependent parameterization modified the ice crystals concentrations but did not affect the total precipitation in the domain. Aerosol regeneration modified the concentration of cloud droplets at cloud base by dynamic recirculation of the aerosols but also had only a minor effect on precipitation.

    The major conclusion from this study is that the effect of mineral dust particles on clouds and total precipitation is limited by the properties of the atmospheric dynamics and the only effect of aerosol on precipitation may come from significant increase in the concentration

  5. Isotopic composition of past precipitation

    International Nuclear Information System (INIS)

    The distribution of stable isotopes in precipitation provides critical quantitative information about the global water cycle. The first PAGES/IAEA ISOMAP workshop was held at the IAEA headquarters in Vienna, 24-26 August 1998, which gathered 32 participants. The presentation and discussions demonstrated that a high level of sophistication already exists in the development of transfer functions between measured parameters and precipitation, as a result of the extensive use of water isotope tracers in paleo-environmental investigations, but a major challenge facing both producers and users of paleo-isotope data is the effective management of data and meta-data, to permit ready retrieval of raw and inferred data for comparison and reinterpretation. This will be in important goal of future ISOMAP activities. The critical need for more paleo-data from low latitudes was clearly recognized

  6. Protein recovery from surfactant precipitation.

    Science.gov (United States)

    Cheng, Shu Ian; Stuckey, David C

    2011-01-01

    The recovery of lysozyme from an aqueous solution containing precipitated lysozyme-AOT complexes formed by the direct addition of sodium bis-(2-ethylhexyl) sulfosuccinate (AOT) to a lysozyme solution was studied using both solvents, and a counterionic surfactant. Ethanol,methanol and solvent mixtures dissolved the surfactant precipitate and recovered lysozyme as a solid. Recovery efficiency and protein stability varied with the type of solvent used. An entirely different method of recovery was also evaluated using a counterionic surfactant: tri-octylmethylammonium chloride (TOMAC) which bound to AOT releasing lysozyme into solution.Complete recovery (100%) of lysozyme was achieved at a molar ratio of 2:1(TOMAC:AOT), and the original protein activity was maintained in the final aqueous phase.The recovered lysozyme retained its secondary structure as observed in circular dichroism(CD) spectra. Specific activity studies show that counterionic surfactant extraction does not alter the biological activity of the enzyme. PMID:22235487

  7. Precipitation variability and predictability in the GFDL General Circulation Model

    Science.gov (United States)

    Luo, L.; Wood, E. F.; Gordon, C. T.; Malyshev, S. L.

    2004-05-01

    The AM2P11 version of the GFDL FMS GCM is intergrated for 22 years (1979-2000) in an AMIP-type setup with 16 ensembles. The variability of annual and seasonal precipitation is studied. We have speculated that the precipitation variability can be related to several components of the climate system, including the Sea Surface Temperature(SST), the land surface and the atmosphere itself, following the work by Koster et al. (1995). A series of experiments were carried out where the variations of these components are enabled or disabled. The changes in precipitation variability from one experiment to another are considered to be directly related to the changes in the boundary conditions. We have identified regions that are sensitive to SST variations and regions where land boudary condition also plays an important role, hence there is potential predictiability of precipitation in the GFDL GCM given the SST and soil moisture information. This potential predictability study provides us guidence on where and when the land surface will help to improve the seasonal-to-interannual predictions. For regions where land surface is important, a good soil moisture initialization scheme is expected to be able to improve the seasonal prediction, in conjunction with an accurate SST forecast.

  8. Precipitation of Relativistic Electrons from the Drift Loss Cone

    Science.gov (United States)

    Lorentzen, K. R.; Looper, M. D.; Blake, J. B.; Millan, R. M.; Smith, D. M.; Lin, R. P.

    2001-12-01

    On Jan. 22, 2000, the MAXIS (MeV Auroral X-ray and Spectroscopy) experiment observed a relativistic electron precipitation event using balloon-borne X-ray detectors. The X-ray spectrum from this event is consistent with atmospheric bremsstrahlung from precipitating electrons peaked between 2 and 3 MeV. This event occurred at L =3.8 in the duskside southern hemisphere, near the western edge of the South Atlantic Anomaly. Several minutes before the start of the balloon event, the SAMPEX satellite observed an intense relativistic electron microburst event in the dawnside northern hemisphere. Tracing the mirror point of electrons observed by SAMPEX indicates that some of these microburst electrons were located in the drift loss cone, and would have precipitated near the location of the balloon measurement. We model the electron drift and scatter in order to examine how the temporal structure and energy spectrum of the precipitating particles change as they drift around the Earth. These observations have implications for quantifying the loss of relativistic electrons from the radiation belts.

  9. Modelling West African Total Precipitation Depth: A Statistical Approach

    Directory of Open Access Journals (Sweden)

    S. Sovoe

    2015-09-01

    Full Text Available Even though several reports over the past few decades indicate an increasing aridity over West Africa, attempts to establish the controlling factor(s have not been successful. The traditional belief of the position of the Inter-tropical Convergence Zone (ITCZ as the predominant factor over the region has been refuted by recent findings. Changes in major atmospheric circulations such as African Easterly Jet (AEJ and Tropical Easterly Jet (TEJ are being cited as major precipitation driving forces over the region. Thus, any attempt to predict long term precipitation events over the region using Global Circulation or Local Circulation Models could be flawed as the controlling factors are not fully elucidated yet. Successful prediction effort may require models which depend on past events as their inputs as in the case of time series models such as Autoregressive Integrated Moving Average (ARIMA model. In this study, historical precipitation data was imported as time series data structure into an R programming language and was used to build appropriate Seasonal Multiplicative Autoregressive Integrated Moving Average model, ARIMA (p, d, q*(P, D, Q. The model was then used to predict long term precipitation events over the Ghanaian segment of the Volta Basin which could be used in planning and implementation of development policies.

  10. Analysis of stability parameters in relation to precipitation associated with pre-monsoon thunderstorms over Kolkata, India

    Indian Academy of Sciences (India)

    H P Nayak; M Mandal

    2014-06-01

    The upper air RS/RW (Radio Sonde/Radio Wind) observations at Kolkata (22.65N, 88.45E) during premonsoon season March–May, 2005–2012 is used to compute some important dynamic/thermodynamic parameters and are analysed in relation to the precipitation associated with the thunderstorms over Kolkata, India. For this purpose, the pre-monsoon thunderstorms are classified as light precipitation (LP), moderate precipitation (MP) and heavy precipitation (HP) thunderstorms based on the magnitude of associated precipitation. Richardson number in non-uniformly saturated (i*) and saturated atmosphere (i); vertical shear of horizontal wind in 0–3, 0–6 and 3–7 km atmospheric layers; energy-helicity index (EHI) and vorticity generation parameter (VGP) are considered for the analysis. The instability measured in terms of Richardson number in non-uniformly saturated atmosphere (i*) well indicate the occurrence of thunderstorms about 2 hours in advance. Moderate vertical wind shear in lower troposphere (0–3 km) and weak shear in middle troposphere (3–7 km) leads to heavy precipitation thunderstorms. The wind shear in 3–7 km atmospheric layers, EHI and VGP are good predictors of precipitation associated with thunderstorm. Lower tropospheric wind shear and Richardson number is a poor discriminator of the three classified thunderstorms.

  11. "Hot Spots" of Land Atmosphere Coupling

    Science.gov (United States)

    Koster, Randal D.; Dirmeyer, Paul A.; Guo, Zhi-Chang; Bonan, Gordan; Chan, Edmond; Cox, Peter; Gordon, T. C.; Kanae, Shinjiro; Kowalczyk, Eva; Lawrence, David

    2004-01-01

    Previous estimates of land-atmosphere interaction (the impact of soil moisture on precipitation) have been limited by a severe paucity of relevant observational data and by the model-dependence of the various computational estimates. To counter this limitation, a dozen climate modeling groups have recently performed the same highly-controlled numerical experiment as part of a coordinated intercomparison project. This allows, for the first time ever, a superior multi-model approach to the estimation of the regions on the globe where precipitation is affected by soil moisture anomalies during Northern Hemisphere summer. Such estimation has many potential benefits; it can contribute, for example, to seasonal rainfall prediction efforts.

  12. Variance and Predictability of Precipitation at Seasonal-to-Interannual Timescales

    Science.gov (United States)

    Koster, Randal D.; Suarez, Max J.; Heiser, Mark

    1999-01-01

    A series of atmospheric general circulation model (AGCM) simulations, spanning a total of several thousand years, is used to assess the impact of land-surface and ocean boundary conditions on the seasonal-to-interannual variability and predictability of precipitation in a coupled modeling system. In the first half of the analysis, which focuses on precipitation variance, we show that the contributions of ocean, atmosphere, and land processes to this variance can be characterized, to first order, with a simple linear model. This allows a clean separation of the contributions, from which we find: (1) land and ocean processes have essentially different domains of influence, i.e., the amplification of precipitation variance by land-atmosphere feedback is most important outside of the regions (mainly in the tropics) that are most affected by sea surface temperatures; and (2) the strength of land-atmosphere feedback in a given region is largely controlled by the relative availability of energy and water there. In the second half of the analysis, the potential for seasonal-to-interannual predictability of precipitation is quantified under the assumption that all relevant surface boundary conditions (in the ocean and on land) are known perfectly into the future. We find that the chaotic nature of the atmospheric circulation imposes fundamental limits on predictability in many extratropical regions. Associated with this result is an indication that soil moisture initialization or assimilation in a seasonal-to-interannual forecasting system would be beneficial mainly in transition zones between dry and humid regions.

  13. Predictibility in Nowcasting of Precipitation

    Science.gov (United States)

    Zawadzki, I.; Sourcel, M.; Berenguer, M.

    2009-05-01

    Present short term precipitation forecasting is based on two methods: Lagrangian persistence (nowcasting) and numerical weather prediction (NWP). An improvement over these methods is obtained by the combination of the two. The obvious shortcoming of nowcasting is its severe limitation in capturing new development or dissipation of precipitation. NWP has the ability to predict both but very imprecisely. An attempt to correct model errors by post-processing leads to some improvement in the skill of NWP, but the improvement, although significative, is not very impressive. The goal of our effort is to take a step back and to describe, in a quantitative manner, a) the nature of the uncertainties affecting Lagrangian persistence and NWP forecasts, as well as to determineb) the physical causes of the uncertainties. We quantify the uncertainties in short term forecasting due to limitation of nowcasting algorithms and NWP to capture correctly some of the physical phenomena that determine the predictability of precipitation. The first factor considered is the diurnal cycle that appears as the one physically determined factors that limit the precision of short term prediction. We study the cycle in radar mosaics over US and compare this to nowcasts and model outputs. The seasonal and geographical dependence of the diurnal cycle is quantitatively evaluated.

  14. European climate change experiments on precipitation change

    DEFF Research Database (Denmark)

    Beier, Claus

    Presentation of European activities and networks related to experiments and databases within precipitation change......Presentation of European activities and networks related to experiments and databases within precipitation change...

  15. Reconstruction of tritium time series in precipitation of Beijing

    International Nuclear Information System (INIS)

    Human nuclear activities, especially intensive nuclear tests during the 1960s in the world, caused atmospheric tritium concentration increasing significantly, which provided convenient condition for global water cycle research, especially for tracer dating research of groundwater. However, due to the layout of monitoring sites and other reasons, most parts of the world are lack of monitoring data of tritium concentration in precipitation, which brought difficulties in determining the input function which is essential for groundwater tracer dating technique. Based on the analysis of principles and applicability of present reconstruction methods of tritium time series, the tritium time series in precipitation in Beijing during 1953-2002 was reconstructed using combined methods, including Guanbingjun method, trend surface analysis method, trigonometric interpolation method and correlation method. Furthermore, the best method and the best time series curve were elected through comparison of results of different methods. (authors)

  16. Future credible precipitation occurrences in Los Alamos, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Abeele, W.V.

    1980-09-01

    I have studied many factors thought to have influenced past climatic change. Because they might recur, they are possible suspects for future climatic alterations. Most of these factors are totally unpredictable; therefore, they cast a shadow on the validity of derived climatic predictions. Changes in atmospheric conditions and in continental surfaces, variations in solar radiation, and in the earth's orbit around the sun are among the influential mechanisms investigated. Even when models are set up that include the above parameters, their reliability will depend on unpredictable variables totally alien to the model (like volcanic eruptions). Based on climatic records, however, maximum precipitation amounts have been calculated for different probability levels. These seem to correspond well to past precipitation occurrences, derived from tree ring indices. The link between tree ring indices and local climate has been established through regression analysis.

  17. Control of particle precipitation by energy transfer from solar wind

    Science.gov (United States)

    Bremer, J.; Gernandt, H.

    1985-12-01

    The energy transfer function (epsilon), introduced by Perreault and Akasofu (1978), appears to be well suited for the description of the long-term control of the particle precipitation by interplanetary parameters. An investigation was conducted with the objective to test this control in more detail. This investigation included the calculation of hourly epsilon values on the basis of satellite-measured solar wind and IMF (interplanetary magnetic field) data. The results were compared with corresponding geomagnetic and ionospheric data. The ionospheric data had been obtained by three GDR (German Democratic Republic) teams during the 21st, 22nd, and 23rd Soviet Antarctic Expeditions in the time period from 1976 to 1979. It was found that, in high latitudes, the properties of the solar wind exercise a pronounced degree of control on the precipitation of energetic particles into the atmosphere, taking into account a time delay of about one hour due to the occurrence of magnetospheric storage processes.

  18. Effective assimilation of global precipitation: simulation experiments

    OpenAIRE

    Lien, Guo-Yuan; Kalnay, Eugenia; Miyoshi, Takemasa

    2013-01-01

    Past attempts to assimilate precipitation by nudging or variational methods have succeeded in forcing the model precipitation to be close to the observed values. However, the model forecasts tend to lose their additional skill after a few forecast hours. In this study, a local ensemble transform Kalman filter (LETKF) is used to effectively assimilate precipitation by allowing ensemble members with better precipitation to receive higher weights in the analysis. In addition, two other changes i...

  19. Precipitation of organic compounds in soils

    International Nuclear Information System (INIS)

    Precipitation samples collected in Hannover in 1990/1991 were analyzed for various organic compound classes. The following average concentrations were observed: formaldehyde (111 μg/l), acetaldehyde (12.0 μg/l), propionaldehyde (4.7 μg/l), n-alkanes from n-C18H38 to n-C33H68 (52.2 μg/l), polycyclic aromatic hydrocarbons (PAHs) (in summer 1989: 351.0 ng/l, in fall 1989: 765 ng/l) higher fatty acids from C9-C26 (24.9 μg/l), phenol (8.4 μg/l), 3-/4-methylphenol (3.3 μg/l), 2-nitrophenol (0.18 μg/l) 4-nitrophenol (6.1. μg/l) and higher alkanols. These compounds are of predominantly biogenic origin (n-alkanes, fatty acids, n-alkanols), formed by photochemical reaction in the atmosphere (aldehydes, phenols) or due to direct antropogenic sources (PAHs). (orig.)

  20. Precipitation scavenging of 7Be and 137Cs radionuclides in air

    International Nuclear Information System (INIS)

    Atmospheric depositional fluxes of the naturally occurring 7Be of cosmogenic origin and 137Cs from fallout of the Chernobyl accident were measured over a 6-year period (January 1987-December 1992) at Thessaloniki, Greece (40o38'N, 22o58'E). Total precipitation accumulation during 1987-1992 varied between 33.7 cm and 65.2 cm, reflecting a relatively dry (precipitation-free) climate. The activity concentrations of 7Be and 137Cs in rainwater depended on the precipitation rate, being higher for low precipitation rates and lesser for high precipitation rates. 137Cs was removed by rain and snow more efficiently than 7Be. Snowfall was more efficient than rainfall in removing the radionuclides from the atmosphere. The annual bulk depositional fluxes of 7Be varied between 477 and 1133 Bq m-2 y-1 and this variability was attributed to the amount of precipitation and the variations of the atmospheric concentrations of 7Be. The annual bulk depositional fluxes of 137Cs showed a significant decrease over time from 1987 to 1992, resulting in a removal half-life of 1.33 years. The presence of 137Cs in air, and therefore in rainwater and snow, long after the Chernobyl accident (26 April 1986) was mainly due to the resuspension process. The normalized depositional fluxes of both radionuclides showed maximal values during the spring season where the maximum amount of precipitation occurred. The relatively high positive correlation between 7Be and 137Cs normalized depositional fluxes indicates that the scavenging process of local precipitation controlled the fluxes of both radionuclides. The dry depositional flux of 7Be was less than 9.37% of total (wet and dry) depositional flux. The fraction of dry-to-total depositional flux of 137Cs was much higher than that of 7Be, due to the resuspended soil

  1. Climate change projections for precipitation in Portugal

    Science.gov (United States)

    Andrade, C.; Santos, J. A.

    2013-10-01

    The strong irregularity of precipitation in Portugal, which may e.g. trigger severe/extreme droughts and floods, results in a high vulnerability of the country to precipitation inter-annual variability and to its extremes. Furthermore, dryer future climates are projected for Portugal, though there has also been some growing evidence for a strengthening of precipitation extremes. Due to the central role played byprecipitation on many socio-economic sectors and environmental systems, regional climate change assessments for precipitation in Portugal are necessary. This study is focused on analyzing climate change projections for seasonal (3-month) precipitation totals and their corresponding extremes over mainland Portugal. Taking into account the strong seasonality of the precipitation regimes in Portugal, winter (DJF) and summer (JJA) are considered separately. Precipitation datasets generated by a 16-member ensemble of regional climate model experiments from the ENSEMBLES project are used. Percentile-based indices of precipitation are computed and analyzed for a recent past period (1961-2000) and for a near future period (2041-2070). Results for the R5p, R50p and R95p indices highlight significant projected changes in precipitation, with a clear distinction between northwestern Portugal and the rest of the country in both seasons. Overall, precipitation is projected to decrease in both seasons, particularly over northwestern Portugal in winter, despite some significant regional differences. Although precipitation is projected to decrease in most cases, extremely high seasonal precipitations (above the 95th percentile)areexpected to increase in winter.

  2. Photoinduced tellurium precipitation in CdTe

    Science.gov (United States)

    Sugai, Shunji

    1991-06-01

    Tellurium precipitation in CdTe is found to be induced by photoirradiation with energy higher than the energy gap at 240 W/sq cm. It is suggested that this photoinduced precipitation is related with the strong electron-phonon interactions, possibly self-trapped excitons. This irreducible tellurium precipitation may cause a serious problem for the life of semiconductor devices.

  3. An Algorithm for Retrieving Precipitable Water Vapor over Land Based on Passive Microwave Satellite Data

    OpenAIRE

    Fang-Cheng Zhou; Xiaoning Song; Pei Leng; Hua Wu; Bo-Hui Tang

    2016-01-01

    Precipitable water vapor (PWV) is one of the most variable components of the atmosphere in both space and time. In this study, a passive microwave-based retrieval algorithm for PWV over land without land surface temperature (LST) data was developed. To build the algorithm, two assumptions exist: (1) land surface emissivities (LSE) at two adjacent frequencies are equal and (2) there are simple parameterizations that relate transmittance, atmospheric effective radiating temperature, and PWV. Er...

  4. Relationship Between The East Atlantic / West Russian Pattern, NAO and Precipitation In Israel

    Science.gov (United States)

    Kishcha, P.; Krichak, S.; Alpert, P.; Barkan, J.

    Main features of composite precipitation and large-scale synoptic patterns over Israel and the adjacent areas are analyzed using both the Israel precipitation data and the gridded NCEP/NCAR reanalysis monthly data set from 1958 to 1998. The effect of East Atlantic / West Russian (EA/WR) atmospheric oscillation on precipitation is con- sidered. Results of the analysis revealed a statistically significant relationship between the decadal variations of precipitation in Israel and the EA/WR indices that can be described by linear regressions. The effect of an other main circulation regime, the North Atlantic Oscillation (NAO), has also been investigated. It was found that the precipitation in Israel is determined mainly by the EA/WR regime and to a smaller degree by the NAO regime. The precipitation was most intensive when both the NAO and EA/WR indices were positive. These results can explain the observed decadal variations of the precipitation in Israel by the processes associated with the decadal variations in the EA/WR and NAO. The changes of composite patterns of precipita- tion, sea level pressure and wind anomalies from the 41-year means were computed for several successive and partly overlapping 21-year periods. The spatial variations of the wind anomaly patterns associate with the downward long-term tendencies of precipitation in the northern part and the upward tendency in the southern part of Is- rael.

  5. Hybrid approach in statistical bias correction of projected precipitation for the frequency analysis of extreme events

    Science.gov (United States)

    Um, Myoung-Jin; Kim, Hanbeen; Heo, Jun-Haeng

    2016-08-01

    A general circulation model (GCM) can be applied to project future climate factors, such as precipitation and atmospheric temperature, to study hydrological and environmental climate change. Although many improvements in GCMs have been proposed recently, projected climate data are still required to be corrected for the biases in generating data before applying the model to practical applications. In this study, a new hybrid process was proposed, and its ability to perform bias correction for the prediction of annual precipitation and annual daily maxima, was tested. The hybrid process in this study was based on quantile mapping with the gamma and generalized extreme value (GEV) distributions and a spline technique to correct the bias of projected daily precipitation. The observed and projected daily precipitation values from the selected stations were analyzed using three bias correction methods, namely, linear scaling, quantile mapping, and hybrid methods. The performances of these methods were analyzed to find the optimal method for prediction of annual precipitation and annual daily maxima. The linear scaling method yielded the best results for estimating the annual average precipitation, while the hybrid method was optimal for predicting the variation in annual precipitation. The hybrid method described the statistical characteristics of the annual maximum series (AMS) similarly to the observed data. In addition, this method demonstrated the lowest root mean squared error (RMSE) and the highest coefficient of determination (R2) for predicting the quantiles of the AMS for the extreme value analysis of precipitation.

  6. Identifying Precipitation Types Using Dual-Polarization-Based Radar and Numerical Weather Prediction Model Data

    Science.gov (United States)

    Seo, B. C.; Bradley, A.; Krajewski, W. F.

    2015-12-01

    The recent upgrade of dual-polarization with NEXRAD radars has assisted in improving the characterization of microphysical processes in precipitation and thus has enabled precipitation estimation based on the identified precipitation types. While this polarimetric capability promises the potential for the enhanced accuracy in quantitative precipitation estimation (QPE), recent studies show that the polarimetric estimates are still affected by uncertainties arising from the radar beam geometry/sampling space associated with the vertical variability of precipitation. The authors, first of all, focus on evaluating the NEXRAD hydrometeor classification product using ground reference data (e.g., ASOS) that provide simple categories of the observed precipitation types (e.g., rain, snow, and freezing rain). They also investigate classification uncertainty features caused by the variability of precipitation between the ground and the altitudes where radar samples. Since this variability is closely related to the atmospheric conditions (e.g., temperature) at near surface, useful information (e.g., critical thickness and temperature profile) that is not available in radar observations is retrieved from the numerical weather prediction (NWP) model data such as Rapid Refresh (RAP)/High Resolution Rapid Refresh (HRRR). The NWP retrieved information and polarimetric radar data are used together to improve the accuracy of precipitation type identification at near surface. The authors highlight major improvements and discuss limitations in the real-time application.

  7. Projected Precipitation Changes within the Great Lakes Region: A Multi-scale Analysis of Precipitation Intensity and Seasonality

    Science.gov (United States)

    Basile, S.; Steiner, A. L.; Brown, D.; Bryan, A. M.

    2014-12-01

    The Great Lakes region supports a diverse network of agriculture, transportation and tourism centered on some of the largest freshwater bodies of water in the world. Precipitation affects these sectors as concerns about precipitation timing and intensity can affect the agricultural growing season, runoff, and subsequent water quality. Here, we examine precipitation projections for mid-century (2041-2065) within the Great Lakes basin (GLB) and two sub-regions using three climate model ensembles of varying resolutions to constrain and compare associated precipitation uncertainties. These include: 1. atmosphere-ocean models from the CMIP5 global simulations with the RCP 8.5 scenario (12 members, resolution ranging from ~1 to ~3 degrees), 2. dynamically downscaled regional climate models from NARCCAP with the SRES A2 scenario (4 members at ~0.5 degree resolution (50 km)), and 3. high resolution (~0.25 degree resolution (25 km)) regional climate model simulations with the RCP 8.5 scenario (RegCM (hereafter RCM3(HiRes)), 2 members). For the entire GLB, all three ensembles captured the intensity of historical events well, but with a bias in the high intensity precipitation events as compared to observed intensity, with fewer overprediction events by the NARCCAP and RCM3(HiRes) ensembles. Daily probability density functions from three model ensembles reveal consistent increases in high precipitation event probabilities for all seasons, even after accounting for wet model biases during the observation period (1980-1999). Comparing all three ensembles to the historical period for the GLB, both CMIP5 and NARCCAP ensembles capture the annual seasonal cycle with a wet bias in the winter and spring, while the RCM3(HiRes) ensemble shows a dry bias for all seasons except winter. For the Lake Michigan and Western Lake Erie basin sub-regions, the spring and winter biases remain present across ensembles, however the RCM3(HiRes) summer dry bias is reduced. Overall, the three climate

  8. 山西夏季降水年代际变化特征及其与印度洋海温和大气环流的关系%INTERDECADAL VARIATION OF SUMMER PRECIPITATION OVER SHANXI AND ITS RELATIONSHIP WITH THE INDIAN OCEAN SST AND ATMOSPHERIC CIRCULATION

    Institute of Scientific and Technical Information of China (English)

    常钢; 李丽平; 周晋红

    2012-01-01

      Based on the 1960—2011 monthly precipitation data of 65 meteorological stations in Shanxi province, NCEP/NCAR reanalysis data and NOAA monthly sea surface temperature(SST) data, the harmonic analysis, SVD method, Monte Carlo statistical test, EOF method and composite analysis method are used to study the interdecadal variation of summer precipitation in Shanxi and its relationship with the general circulation and the SST abnormalities in Indian Ocean. Results show that summer precipitation of Shanxi has a decreasing trend in the recent 52 years, and it presents a significant interdecadal variation characteristic that more precipitation happened from the early 1960's to early 1980's while less precipitation occurred from the mid-1980's to 2011. The spatial distributions of summer precipitation in Shanxi include consistent type (more or less precipitation in entire Shanxi) and north-south type(more precipitation in north(south), less precipitation in south(north)). There has significant negative correlation between summer rainfall of Shanxi and SST of key area in India ocean, when the SST is anomaly higher in last autumn and winter, this summer precipitation of Shanxi decreases, and vice versa. Before 1982, the SST was lower, the northeast cold vortex and the trough at 500 hPa over Ural Mountains and northern Qinghai-Tibet Plateau were deeper and more active, and the west Pacific subtropical high was weaker and locates more easterly, and the synchronous low-latitude westerly winds and the mid-latitude 850 hPa-southwest wind unusually strengthened and the vortex over Lake Baikal was active. After 1982, the SST was higher, from Lake Baikal to northern Qinghai-Tibet plateau are controlled by high pressure, and the intensity of the 500 hPa western Pacific subtropical high was stronger and located more western. The 850 hPa mid-latitude southwest wind was unusually weaker.%  利用山西省65个气象站1960—2011年逐月降水资料、NCEP/NCAR再分析资

  9. Climatology of Vb-cyclones, physical mechanisms and their impact on extreme precipitation over Central Europe

    Directory of Open Access Journals (Sweden)

    M. Messmer

    2015-05-01

    Full Text Available Cyclones, which develop over the western Mediterranean and move northeastward are a major source of extreme weather and known to be responsible for heavy precipitation over Central Europe and the Alps. As the relevant processes triggering these so-called Vb-events and their impact on extreme precipitation are not yet fully understood, this study focusses on gaining insight into the dynamics of past events. For this, a cyclone detection and tracking tool is applied to the ERA-Interim reanalysis (1979–2013 to identify prominent Vb-situations. Precipitation in the ERA-Interim and the E-OBS datasets is used to evaluate case-to-case precipitation amounts and to assess consistency between the two datasets. Both datasets exhibit high variability in precipitation amounts among different Vb-events. While only 23 % of all Vb-events are associated with extreme precipitation, around 15 % of all extreme precipitation days (99 percentile over the Alpine region are induced by Vb-events, although Vb-cyclones are rare events (2.3 per year. To obtain a better understanding of the variability within Vb-events, the analysis of the 10 heaviest and lowest precipitation Vb-events reveals noticeable differences in the state of the atmosphere. These differences are most pronounced in the geopotential height and potential vorticity field, indicating a much stronger cyclone for heavy precipitation events. The related differences in wind direction are responsible for the moisture transport around the Alps and the orographical lifting along the Alps. These effects are the main reasons for a disastrous outcome of Vb-events, and consequently are absent in the Vb-events associated with low precipitation. Hence, our results point out that heavy precipitation related to Vb-events is mainly related to large-scale dynamics rather than to thermodynamic processes.

  10. Global scale precipitation from monthly to centennial scales: empirical space-time scaling analysis, anthropogenic effects

    Science.gov (United States)

    de Lima, Isabel; Lovejoy, Shaun

    2016-04-01

    The characterization of precipitation scaling regimes represents a key contribution to the improved understanding of space-time precipitation variability, which is the focus here. We conduct space-time scaling analyses of spectra and Haar fluctuations in precipitation, using three global scale precipitation products (one instrument based, one reanalysis based, one satellite and gauge based), from monthly to centennial scales and planetary down to several hundred kilometers in spatial scale. Results show the presence - similarly to other atmospheric fields - of an intermediate "macroweather" regime between the familiar weather and climate regimes: we characterize systematically the macroweather precipitation temporal and spatial, and joint space-time statistics and variability, and the outer scale limit of temporal scaling. These regimes qualitatively and quantitatively alternate in the way fluctuations vary with scale. In the macroweather regime, the fluctuations diminish with time scale (this is important for seasonal, annual, and decadal forecasts) while anthropogenic effects increase with time scale. Our approach determines the time scale at which the anthropogenic signal can be detected above the natural variability noise: the critical scale is about 20 - 40 yrs (depending on the product, on the spatial scale). This explains for example why studies that use data covering only a few decades do not easily give evidence of anthropogenic changes in precipitation, as a consequence of warming: the period is too short. Overall, while showing that precipitation can be modeled with space-time scaling processes, our results clarify the different precipitation scaling regimes and further allow us to quantify the agreement (and lack of agreement) of the precipitation products as a function of space and time scales. Moreover, this work contributes to clarify a basic problem in hydro-climatology, which is to measure precipitation trends at decadal and longer scales and to

  11. Precipitation Characteristics of ISCCP Cloud Regimes for Improving Model Hydrological Budgets

    Science.gov (United States)

    Lee, D.; Oreopoulos, L.

    2011-01-01

    The key in unraveling relationships between precipitation and atmospheric circulations is their common linkage to clouds. Clouds can be described in a variety of ways and several approaches can be adopted to examine their connections to precipitation. We claim that when cloud regimes (aka weather states) from the International Satellite Cloud Climatology Project (ISCCP) are used to conditionally sample/sort and average precipitation data, useful insight and GCM-appropriate diagnostics on the origins and distribution of precipitation can be obtained. The ISCCP cloud regimes are mesoscale (2.5 ) cloud mixtures determined by cluster analysis on joint histograms of cloud optical thickness and cloud top pressure inferred from geostationary and polar orbiter satellite passive retrievals. The ISCCP cloud regime data are combined with GPCP IDD merged surface precipitation data and/or higher temporal and spatial resolution TRMM Multi-Satellite Precipitation Analysis (TMPA) data. The analysis is performed separately for three geographical zones, tropics, and northern/southern midlatitudes (for GPCP; only the tropics can be examined with TMPA data). Our presentation aspires to provide answers to the following questions: (l) What is the mean and variability of surface precipitation produced by each cloud regime at the time of regime occurrence? (2) What is the relative contribution of each cloud regime to the total precipitation within its geographical zone? (3) What is the geographical distribution of precipitation corresponding to particular cloud regime? (4) To what extent are the cloud regimes distinct in terms of their precipitation characteristics and is the regime ordering in terms of convective strength consistent with the observed precipitation intensity?

  12. Precipitation interpolation in mountainous areas

    Science.gov (United States)

    Kolberg, Sjur

    2015-04-01

    Different precipitation interpolation techniques as well as external drift covariates are tested and compared in a 26000 km2 mountainous area in Norway, using daily data from 60 stations. The main method of assessment is cross-validation. Annual precipitation in the area varies from below 500 mm to more than 2000 mm. The data were corrected for wind-driven undercatch according to operational standards. While temporal evaluation produce seemingly acceptable at-station correlation values (on average around 0.6), the average daily spatial correlation is less than 0.1. Penalising also bias, Nash-Sutcliffe R2 values are negative for spatial correspondence, and around 0.15 for temporal. Despite largely violated assumptions, plain Kriging produces better results than simple inverse distance weighting. More surprisingly, the presumably 'worst-case' benchmark of no interpolation at all, simply averaging all 60 stations for each day, actually outperformed the standard interpolation techniques. For logistic reasons, high altitudes are under-represented in the gauge network. The possible effect of this was investigated by a) fitting a precipitation lapse rate as an external drift, and b) applying a linear model of orographic enhancement (Smith and Barstad, 2004). These techniques improved the results only marginally. The gauge density in the region is one for each 433 km2; higher than the overall density of the Norwegian national network. Admittedly the cross-validation technique reduces the gauge density, still the results suggest that we are far from able to provide hydrological models with adequate data for the main driving force.

  13. Phase transitions precipitated by solitosynthesis

    CERN Document Server

    Kusenko, A

    1997-01-01

    Solitosynthesis of Q-balls in the false vacuum can result in a phase transition of a new kind. Formation and subsequent growth of Q-balls via the charge accretion proceeds until the solitons reach a critical charge, at which point it becomes energetically favorable for the Q-ball interior to expand filling space with the true vacuum phase. Solitosynthesis can destabilize a false vacuum even when the tunneling rate is negligible. In models with low-energy supersymmetry, where the Q-balls associated with baryon and lepton number conservation are generically present, solitosynthesis can precipitate transitions between the vacua with different VEV's of squarks and sleptons.

  14. Struvite Precipitation and Biological Dissolutions.

    OpenAIRE

    Ezquerro, Ander

    2010-01-01

    Struvite is a salt that is formed out of  Mg2+,NH4+ and PO43- and it crystallizes in form of MgNH4PO4.6H2O. Struvite‟s (magnesium ammonium phosphate or MAP) precipitation has recently been regarded as an interesting technique to remove phosphate and ammonium from waste water. The high elimination rates and the possibility of recycling the struvite as a direct slow release fertilizer make this process feasible and appealing. However, the costs due to the raw chemicals needed are drawbacks that...

  15. Radiation Induced Precipitation in Iron

    International Nuclear Information System (INIS)

    Foils of iron have been neutron-irradiated in the Swedish re- search reactor R2 to integrated doses in the range 1017 - 1019 nvt (> 1 MeV) and examined by transmission electron microscopy. Features have been observed having diffraction contrast similar to that of the prismatic dislocation loops formed in f.c.c. metals by the collapse of point-defect clusters. The features have been shown to be due to precipitation of impurities at radiation damage centres in the iron matrix

  16. Homogeneous oxalate precipitation of Pu(III)

    International Nuclear Information System (INIS)

    This paper reports on homogeneous oxalate precipitation using diethyl oxalate which was compared to precipitating Pu(III) oxalate with solid oxalic acid. The diethyl oxalate technique at 75 degrees C is better because it gives 50% less plutonium in the filtrate with a reasonable filtering time. Also, the procedure for the homogeneous precipitation is easier to automate because the liquid diethyl oxalate is simpler to introduce into the precipitator than solid oxalic acid. It also provides flexibility because the hydrolysis rate and therefore the precipitation rate can be controlled by varying the temperature

  17. Thermal stability of copper precipitates in silicon

    International Nuclear Information System (INIS)

    The dissolution of copper precipitates in Czochralski silicon has been studied with synchrotron-based x-ray fluorescence. Copper has been introduced and allowed to precipitate at oxygen precipitates and growth-related stacking faults. The dissolution of copper precipitates is monitored after low-temperature anneals. This study is designed to determine whether copper can be released from these precipitation sites at low temperatures such that contamination and subsequent device degradation of an integrated circuit device could occur. Our results demonstrate copper dissolution back into the silicon matrix at temperatures as low as 360oC

  18. Acidic precipitation: considerations for an air-quality standard

    Energy Technology Data Exchange (ETDEWEB)

    Evans, L.S.; Hendrey, G.R.; Stensland, G.J.; Johnson, D.W.; Francis, A.J.

    1980-01-01

    Acidic precipitation, wet or frozen deposition with a hydrogen ion concentration greatern than 2.5 ..mu..eq l/sup -1/ is a significant air pollution problem in the United States. The chief anions accounting for the hydrogen ions in rainfall are nitrate and sulfate. Agricultural systems are more likely to derive net nutritional benefits from increasing inputs of acidic rain than are forest systems when soils alone are considered. Agricultural soils may benefit because of the high N and S requirements of agricultural plants. Detrimental effects to forest soils may result if atmospheric H/sup +/ inputs significantly add to or exceed H/sup +/ production by soils. Acidification of fresh waters of southern Scandinavia, southwestern Scotland, southeastern Canada, and northeastern United States is caused by acid deposition. Areas of these regions in which this acidification occurs have in common, highly acidic precipitation with volume weighted mean annual H/sup +/ concentrations of 25 ..mu..eq l/sup -1/ or higher and slow weathering granitic or precambrian bedrock with thin soils deficient in minerals which would provide buffer capacity. Biological effects of acidification of fresh waters are detectable below pH 6.0. As lake and stream pH levels decrease below pH. 6.0, many species of plants, invertebrates, and vertebrates are progressively eliminated. Generally, fisheries are impacted below pH 5.0 and are completely destroyed below pH 4.8. There are few studies that document effects of acidic precipitation on terrestrial vegetation to establish an air quality standard. It must be demonstrated that current levels of precipitation acidity alone significantly injure terrestrial vegetation. In terms of documented damanges, current research indicates that establishing a standard for precipitation for the volume weighted annual H/sup +/ concentration at 25 ..mu..eq l/sup -1/ may protect the most sensitive areas from permanent lake acidification.

  19. Global Precipitation Climatology Centre (GPCC)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — First is the monitoring product for the period 2007 to present, based on quality-controlled data from 7,000 stations. The second is the Full Data Product (V7)for...

  20. Observed and simulated precipitation responses in wet and dry regions 1850–2100

    International Nuclear Information System (INIS)

    Global warming is expected to enhance fluxes of fresh water between the surface and atmosphere, causing wet regions to become wetter and dry regions drier, with serious implications for water resource management. Defining the wet and dry regions as the upper 30% and lower 70% of the precipitation totals across the tropics (30° S–30° N) each month we combine observations and climate model simulations to understand changes in the wet and dry regions over the period 1850–2100. Observed decreases in precipitation over dry tropical land (1950–2010) are also simulated by coupled atmosphere–ocean climate models (−0.3%/decade) with trends projected to continue into the 21st century. Discrepancies between observations and simulations over wet land regions since 1950 exist, relating to decadal fluctuations in El Niño southern oscillation, the timing of which is not represented by the coupled simulations. When atmosphere-only simulations are instead driven by observed sea surface temperature they are able to adequately represent this variability over land. Global distributions of precipitation trends are dominated by spatial changes in atmospheric circulation. However, the tendency for already wet regions to become wetter (precipitation increases with warming by 3% K−1 over wet tropical oceans) and the driest regions drier (precipitation decreases of −2% K−1 over dry tropical land regions) emerges over the 21st century in response to the substantial surface warming. (letter)

  1. Remote sensing of precipitable water over the oceans from Nimbus-7 microwave measurements

    Science.gov (United States)

    Prabhakara, C.; Change, H. D.; Chang, A. T. C.

    1981-01-01

    Global maps of precipitable water over derived from scanning multichannel microwave radiometer (SMMR) data reveal salient features associated with ocean currents and the large scale general circulation in the atmosphere. Nimbus-7 SMMR brightness temperature measurements in the 21 and 18 GHz channels are used to sense the precipitable water in the atmospheric over oceans. The difference in the brightness temperature (T sub 21 -T sub 18), both in the horizontal and vertical polarization, is found to be essentially a function of the precipitable water in the atmosphere. An equation, based on the physical consideration of the radiative transfer in the microwave region, is developed to relate the precipitable water to (T sub 21 - T sub 18). It shows that the signal (T sub 21- T sub 18) does not suffer severely from the noise introduced by variations in the sea surface temperature, surface winds, and liquid water content in non rain clouds. The rms deviation between the estimated precipitable water from SMMR data and that given by the closely coincident ship radiosondes is about 0.25 g/ sq cm

  2. Short period forecasting of catchment-scale precipitation. Part I: the role of Numerical Weather Prediction

    Directory of Open Access Journals (Sweden)

    M. A. Pedder

    2000-01-01

    Full Text Available A deterministic forecast of surface precipitation involves solving a time-dependent moisture balance equation satisfying conservation of total water substance. A realistic solution needs to take into account feedback between atmospheric dynamics and the diabatic sources of heat energy associated with phase changes, as well as complex microphysical processes controlling the conversion between cloud water (or ice and precipitation. Such processes are taken into account either explicitly or via physical parameterisation schemes in many operational numerical weather prediction models; these can therefore generate precipitation forecasts which are fully consistent with the predicted evolution of the atmospheric state as measured by observations of temperature, wind, pressure and humidity. This paper reviews briefly the atmospheric moisture balance equation and how it may be solved in practice. Solutions are obtained using the Meteorological Office Mesoscale version of its operational Unified Numerical Weather Prediction (NWP model; they verify predicted precipitation rates against catchment-scale values based on observations collected during an Intensive Observation Period (IOP of HYREX. Results highlight some limitations of an operational NWP forecast in providing adequate time and space resolution, and its sensitivity to initial conditions. The large-scale model forecast can, nevertheless, provide important information about the moist dynamical environment which could be incorporated usefully into a higher resolution, ‘storm-resolving’ prediction scheme. Keywords: Precipitation forecasting; moisture budget; numerical weather prediction

  3. Heavy precipitation episodes and cosmic rays variation

    Directory of Open Access Journals (Sweden)

    A. Mavrakis

    2006-01-01

    Full Text Available In this paper an attempt is made to investigate the possible temporal correlation between heavy precipitation episodes and cosmic rays' activity, on various time scales. Cosmic rays measurements are sparse and cover less extended periods than those of precipitation. Precipitation is largely influenced by local climatic and even physiographic conditions, while cosmic rays' distribution is far more uniform over an area. Thus, in an effort to cover a larger range of climatic characteristics, each cosmic rays station was correlated with several nearby precipitation stations. Selected statistical methods were employed for the data processing. The analysis was preformed on annual, seasonal, monthly and daily basis whenever possible. Wet and dry regions and/or seasons seem to present a different response of precipitation to cosmic rays variations. Also Forbush decreases in most cases will not lead to heavy precipitation, yet this might be sensitive to precipitable water availability.

  4. Estimating Tropical Cyclone Precipitation from Station Observations

    Institute of Scientific and Technical Information of China (English)

    REN Fumin; WANG Yongmei; WANG Xiaoling; LI Weijing

    2007-01-01

    In this paper, an objective technique for estimating the tropical cyclone (TC) precipitation from station observations is proposed. Based on a comparison between the Original Objective Method (OOM) and the Expert Subjective Method (ESM), the Objective Synoptic Analysis Technique (OSAT) for partitioning TC precipitation was developed by analyzing the western North Pacific (WNP) TC historical track and the daily precipitation datasets. Being an objective way of the ESM, OSAT overcomes the main problems in OOM,by changing two fixed parameters in OOM, the thresholds for the distance of the absolute TC precipitation (D0) and the TC size (D1), into variable parameters.Case verification for OSAT was also carried out by applying CMORPH (Climate Prediction Center MORPHing technique) daily precipitation measurements, which is NOAA's combined satellite precipitation measurement system. This indicates that OSAT is capable of distinguishing simultaneous TC precipitation rain-belts from those associated with different TCs or with middle-latitude weather systems.

  5. Precipitation in low energy helium irradiated molybdenum

    International Nuclear Information System (INIS)

    The precipitation of low energy helium injected into molybdenum has been monitored by thermal helium desorption spectrometry (THDS). Precipitates nucleating at vacancies have been studied in the range from n = 1 to n = 2500 He per precipitate. The behaviour of the growing precipitates with respect to helium trapping, self-interstitial capture and emission, and helium release is discussed against the background of results of TEM work done for precipitates with n > 500 He. Evidence is found for (i) 'trap mutation' at n = 10 He, i.e. formation of bound self-interstitials around the helium filled vacancy, and (ii) emission of at least one of these 'mutation produced self-interstitials' (MPI) at n approx. 12 He. For larger precipitates (n > 20 He) the emission of single MPI is not apparent. At n = 1000 signs of helium binding to MPI-loops punched out by the precipitates are observed in the spectra. (author)

  6. Process of molybdenum transfer in iodine atmosphere

    International Nuclear Information System (INIS)

    The process of molybdenum transfer in iodine atmosphere is studied. The dependence of the rate of molybdenum extraction in the hot zone on iodine content in ampula and temperature conditions is experimentally investigated; thermodynamic analysis of dissociation process of molybdenum diiodide is performed. It is established that in iodine atmosphere Mo is transported into the hot zone in the 920-1520 K range. Maximum rate of Mo precipitation at the thread is achieved under conditions of diiodide evaporation at 970 K and temperature of glower of 1150-1350 K. Mo separates in the process of thermal dissociation of molybdenum diiodide

  7. Hemispheric Assymeries in Auroral Precipitation

    Science.gov (United States)

    Mende, S. B.

    2014-12-01

    It is widely accepted that the space weather related electrodynamic forcing of the geospace environment acts through the high geomagnetic latitude regions. At high latitudes inter-hemispheric asymmetries are largely due to the differences in solar illumination, the direction of the solar wind and interplanetary magnetic field components and to a lesser extent, due to differences between the two hemispheric internal fields. So far most research regarding interhemispheric differences concentrated on learning about the basic magnetosphere-ionosphere coupling mechanisms. It has been well established that sunlit conditions affect the energy flux of auroral precipitation resulting from the reduction in the mean energy of the auroral electrons in the sunlit summer hemisphere. This can be explained by the partial shorting out of the particle accelerating fields by the sunlight induced conductivity. It has also been found that sunlit conditions reduce the particle fluxes and therefore the associated field aligned currents. Unless the precipitation-induced conductivities overwhelm the sunlit component of conductivity, this would imply that the magnetospheric current generator responds to the ionospheric load in a highly non-linear manner. Interhemispheric currents may also play an important role that has not been fully explored. Interhemispheric asymmetries in substorm morphology have been explored critically because conjugacy implies that substorms have a common source at equatorial latitudes. In some cases the lack of conjugacy of substorms could be explained by considering the magnitude and direction of the IMF.

  8. Radiative feedbacks on global precipitation

    International Nuclear Information System (INIS)

    The radiative kernel technique is employed to quantify twenty-first century changes to the tropospheric energy budget in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) models in order to better understand changes in global-mean precipitation. The strongest feedbacks on the tropospheric radiative cooling are found to be associated with increases in temperature and water vapor, with the water vapor feedback offsetting a significant portion (∼39%) of the increase in radiative cooling due to higher temperatures. Cloud and surface sensible heat flux feedbacks, though not as large in magnitude as the temperature and water vapor feedbacks, are important contributors to the intermodel difference in the global precipitation response to warming, or hydrological sensitivity. The direct effects of radiative forcing agents on the tropospheric energy budget are also important. Rising CO2 levels reduce tropospheric radiative cooling and hence limit the increase in global rainfall. Additionally, in some of the models, further reductions in radiative cooling occur due to increases in absorbing aerosol, suggesting that differences in aerosol forcing can explain part of the difference in hydrological sensitivity between models.

  9. Numerical simulation of asymmetric particle precipitation by pitch angle diffusion

    Science.gov (United States)

    Thorne, Richard M.; Abel, Robert W.; Summers, Danny

    1996-11-01

    A numerical simulation code is developed to evaluate the loss rate of particles trapped in a mirror magnetic field geometry with asymmetric loss cones. The one-dimensional model can accommodate particle diffusion at any prescribed rate and loss cones of any prescribed sizes, and it incorporates the important effect of atmospheric backscattering. Numerical solutions for the loss cone particle distribution function calculated for the case of equal loss cones provide an acceptable simulation of the well-known modified Bessel function solution. The code provides the first quantitative solutions for any specified rate of pitch angle scattering for the general case of arbitrary asymmetry in loss cone size. In the case of weak or moderate diffusion the ratio of particle precipitation fluxes into the two loss cones can provide a sensitive measurement of the rate of particle scattering, but to utilize this important diagnostic property, one must also have information on the fraction of particles that are backscattered from the atmosphere.

  10. Current state of studying precipitation acidification in Serbia

    Directory of Open Access Journals (Sweden)

    Talijan Radomir

    2015-01-01

    Full Text Available Basic relations between the state of air pollution and their effects on chemistry of precipitation were introduced in this paper. Changes in the composition of atmosphere were defined by numerous chemical elements and compounds different in character which also affect the phenomenon of acidification and alkaline processes. The interconnected sources of emission, relations between urban and rural, the regime of rainmeasuring system and climate elements combined as whole give us more complete image of the global phenomenon and its effects on cities as a contemporary social development first of all caused by industrialization, its dependance upon fosil sources of energy and demographic pressure. Characteristics of main pollutants were considered as well as their ability to modify atmospheric conditions, but also the influence of climate elements on those conditions, ph rainfall average value movement, seasonal and daily variations, the influence of industrial zones and agglomeration on the conditions in the area much wider than emitters.

  11. The usefulness of the Global Navigation Satellite Systems (GNSS) in the analysis of precipitation events

    Science.gov (United States)

    Bonafoni, Stefania; Biondi, Riccardo

    2016-01-01

    It is well known that the use of the Global Navigation Satellite Systems (GNSS), both with ground-based and Low Earth Orbit (LEO) receivers, allows retrieving atmospheric parameters in all the weather conditions. Ground-based GNSS technique provides the integrated precipitable water vapour (IPWV) with temporal continuity at a specific receiver station, while the GNSS LEO technique allows for Radio Occultation (RO) observations of the atmosphere, providing a detailed atmospheric profiling but without temporal continuity at a specific site. In this work, several precipitation events that occurred in Italy were analysed exploiting the potential of the two GNSS techniques (i.e. ground-based and space-based GNSS receivers). From ground-based receivers, time series of IPWV were produced at specific locations with the purpose of analysing the water vapour behaviour during precipitation events. From LEO receivers, the profiling potential was exploited to retrieve the cloud top altitude of convective events, taking into account that although GNSS RO could capture the dynamics of the atmosphere with high vertical resolution, the temporal resolution is not enough to continuously monitor such an event in a local area. Therefore, the GNSS technique can be considered as a supplemental meteorological system useful in studying precipitation events, but with very different spatial and temporal features depending on the receiver positioning.

  12. Precipitation and Obscuration Processing of Aerosol Particles at Rural Background Station

    Czech Academy of Sciences Publication Activity Database

    Zíková, Naděžda; Ondráček, Jakub; Ždímal, Vladimír

    - : -, 2014, OP38-6. ISBN N. [International Aerosol Conference 2014. Busan (KR), 28.08.2014-02.09.2014] R&D Projects: GA ČR GAP209/11/1342 Institutional support: RVO:67985858 Keywords : atmospheric aerosol * SMPS * precipitation Subject RIV: CF - Physical ; Theoretical Chemistry

  13. Precipitation and Hydrology Experiment Counter-Flow Spectrometer and Impactor Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Poellot, Michael [University of North Dakota

    2016-03-01

    The U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility Aerial Facility (ARM AAF) counter-flow spectrometer and impactor (CSI) probe was flown on the University of North Dakota Cessna Citation research aircraft during the Integrated Precipitation and Hydrology Experiment (IPHEX). The field campaign took place during May and June of 2014 over North Carolina and its coastal waters as part of a National Aeronautics and Space Administration (NASA) Global Precipitation Measurement validation campaign. The CSI was added to the Citation instrument suite to support the involvement of Jay Mace through the NASA Advanced Composition Explorer (ACE) satellite program and flights of the NASA ER-2 aircraft, which is a civilian version of the Air Force’s U2-S reconnaissance platform. The ACE program funded extra ER-2 flights to focus on clouds that are weakly precipitating, which are also of interest to the Atmospheric System Research program sponsored by DOE.

  14. FORSGC Network for isotopes in precipitation over the Monsoon Asia

    International Nuclear Information System (INIS)

    Full text: The GNIP project provides the monthly data of stable isotopes in precipitation all over the world. For the validation of atmospheric water cycle by reanalysis datasets or GCM simulations, however, there are a few stations in Asia. Also, spatial and temporal variability of the stable isotope composition of precipitation in the Asia Pacific region was discussed based on the GNIP monthly dataset, and regional climatology and atmospheric circulation patterns. However, the relationship between isotope signature of precipitation and climate in tropics is not well understood, because the daily isotopic data in precipitation is limited. Since 2000, the isotope group of the Frontier Observational Research System for Global Change (FORSGC) had been collecting the daily precipitation samples for stable isotopes over the Monsoon Asia, such as Siberia (3 stations), Tibetan Plateau (10 stations), Nepal (5 stations), Thailand (3 stations), Indonesia (5 stations), and Palau Island (1 station). In this study, we will introduce the FORSGC network for stable isotopes in precipitation database and show the short-term (monthly and daily) variability of precipitation isotopes observed in Thailand and Indonesia and so on. The daily rainfall samples were collected during August to December 2001 at ChiangMai, Bangkok and Phuket stations in Thailand. These stations showed similar monthly variability in Oxygen-18, and most ranged from -15 per mille to 0 per mille. There were increasing trends in August and November, while decreasing trend in September. Daily variability, however, showed a different trend. A depletion of early-August at ChiangMai and a sudden enrichment around 10 October at Phuket were appeared. Considering relationships between Oxygen-18 and precipitation amount, there were positive correlations in three stations by the monthly basis. In general, isotopic compositions are heavy in low precipitation and light in high precipitation caused by the amount effect. The

  15. Bulk precipitation chemistry at the forest and forest village

    Science.gov (United States)

    Gökbulak, Ferhat; Şengönül, Kamil; Serengil, Yusuf; Yurtseven, İbrahim; Uygur, Betul; Özhan, Süleyman; Özcan, Mehmet

    2013-12-01

    The objectives of this study were to characterize and compare selected physical and chemical properties of precipitation in a broadleaf mixed forest and a village located in the same forest in order to determine the influence of the village on the atmospheric environmental quality of the forest ecosystem. Bulk precipitation samples were collected weekly from October 2005 to July 2011. Precipitation samples were analyzed for pH, electrical conductivity (EC), turbidity, total suspended particles (TSP), total alkalinity (CaCO3), alkalinity (HCO3-), chloride (CI-), total hardness (CaCO3), Ca hardness (CaCO3), calcium (Ca2 +), magnesium (Mg2 +), organic matter, total nitrogen (N), sodium (Na+), potassium (K+), nitrate (NO3)-, phosphate (PO4)3 -, iron (Fe), aluminum (Al), ammonium (NH4)+, and sulfate (SO4)2 -. The precipitation samples from forest and forest village were significantly different from each other for EC, total alkalinity (CaCO3), HCO3-, Ca hardness (CaCO3), Ca2 +, total N, K+, NO3-, and NH4+. Regardless of the study sites, PO43 - and Mg2 + were dominant anion and cation, respectively. The orders of cation and anion concentrations were similar for both study sites and they were in descending order of Mg2 + > Ca2 + > Na+ > K+ > NH4+ > Fe > Al > H+ and PO43 - > HCO3- > SO42 - > CI- > NO3-, respectively. Overall average monthly values of precipitation characteristics did not show significant difference between months except for pH, EC, total alkalinity (CaCO3), and HCO3-. Significant correlations were found between SO42 - and pH, Ca2 +, NH4+ and between NO3- and NH4+ for the precipitation event at the forest site. Both study sites had pH values higher than 5.6 due to the neutralization of SO42 - and NO3- by NH4+ and Ca2 +. Significant correlation coefficients found between the study sites for the same precipitation parameter indicated that both study sites were under the influence of the same emission sources.

  16. Observations and Modeling of Tropical Planetary Atmospheres

    Science.gov (United States)

    Laraia, Anne

    2016-01-01

    This thesis is a comprised of three different projects within the topic of tropical atmospheric dynamics. First, I analyze observations of thermal radiation from Saturn's atmosphere and from them, determine the latitudinal distribution of ammonia vapor near the 1.5-bar pressure level. The most prominent feature of the observations is the high brightness temperature of Saturn's subtropical latitudes on either side of the equator. After comparing the observations to a microwave radiative transfer model, I find that these subtropical bands require very low ammonia relative humidity below the ammonia cloud layer in order to achieve the high brightness temperatures observed. We suggest that these bright subtropical bands represent dry zones created by a meridionally overturning circulation. Second, I use a dry atmospheric general circulation model to study equatorial superrotation in terrestrial atmospheres. A wide range of atmospheres are simulated by varying three parameters: the pole-equator radiative equilibrium temperature contrast, the convective lapse rate, and the planetary rotation rate. A scaling theory is developed that establishes conditions under which superrotation occurs in terrestrial atmospheres. The scaling arguments show that superrotation is favored when the off-equatorial baroclinicity and planetary rotation rates are low. Similarly, superrotation is favored when the convective heating strengthens, which may account for the superrotation seen in extreme global-warming simulations. Third, I use a moist slab-ocean general circulation model to study the impact of a zonally-symmetric continent on the distribution of monsoonal precipitation. I show that adding a hemispheric asymmetry in surface heat capacity is sufficient to cause symmetry breaking in both the spatial and temporal distribution of precipitation. This spatial symmetry breaking can be understood from a large-scale energetic perspective, while the temporal symmetry breaking requires

  17. Temporal variation of stable isotopes in precipitation at Bangkok, Thailand

    International Nuclear Information System (INIS)

    Full text: Some studies discussed spatial and temporal variability of the stable isotope composition of precipitation in the Asia Pacific region. However, the relationship between isotope signature of precipitation and climate is not well understood, because the long-term isotopic data in precipitation is limited. The purpose of this study is to understand the observed by the IAEA/GNIP network. (author) period and, on the other precipitation mechanism in Monsoon Asia region in response with El Nino/Southern Oscillation. The monthly averaged stable isotopes (Oxygen-18, Deuterium) in precipitation and meteorological data for the period of 1968 to 1995 at Bangkok (13.73 deg N, 100.5 deg E), which are provided by the Global Network for Isotopes in Precipitation. The vertically integrated precipitable water and moisture flux datasets in NCEP/NCAR global atmospheric reanalysis with 2.5 deg. x 2.5 deg. resolution are used to determine the circulation anomalies for the period of 1979 to 1995. To consider the influence of El Nino/Southern Oscillation to precipitation in Bangkok, correlations between oxygen-18 of precipitation and SST in Nino-3 region (that is ENSO index) are considered for each month. The positive correlations with statistically 95% significant level are found only May and October, which is onset and offset period of Asian Monsoon in Thailand. The correlation coefficient is 0.39 for May and 0.62 for October. The isotopic low-phase years in May are 1981, 86, 88 and 91, and isotopic high-phase years are 1979, 80, 83, 87, 92, 94 and 95. Also, the isotopic low-phase year in October are 1988, 90 and 95, and isotopic high-phase years are 1979, 80, 82, 91 and 94. The large-scale circulation fields are considered to elucidate the cause the variations of stable isotopes in precipitation and its relation to ENSO. Composite mean of precipitable water (PW) and moisture flux (UQ, VQ) anomalies for isotopic low and high phases in May and October are considered. An

  18. Eocene precipitation: How wet do greenhouse climates get? (Invited)

    Science.gov (United States)

    Greenwood, D. R.; Smith, R. Y.

    2010-12-01

    Columbia. Precipitation for western North America at mid-latitudes is also estimated as high, but a seasonally dry interior and south-east is indicated. For Australia, mesothermal climates prevailed (MAT 15-18°C), and precipitation in the south-east is estimated >120 cm/a, but the macrofloras indicate a drier interior (MAP ~60 cm/a), contradicting estimates of ~120 cm/a based on NLR analysis of pollen floras. The predicted enormous volume of freshwater entering the Arctic Ocean as a result of northward drainage of a significant region of the Northern Hemisphere under a high precipitation regime would have strongly affected Arctic Ocean salinity. Much higher than present-day precipitation across much of Eocene Australia is consistent with higher atmospheric humidity in the Antarctic region in the Paleogene. High Paleogene precipitation around the Arctic Basin is consistent with high atmospheric humidity, which would have contributed significantly to polar, and global, Eocene greenhouse warming. These proxy data show a mix of match and mismatch with published model-generated estimates of precipitation for Australia and North America for the Eocene greenhouse climate, and highlight how current models fail to reproduce the extensive wet climates of the ‘undiscovered climates’ of the Eocene.

  19. Radiation belt electron precipitation and its ionospheric effects at middle latitudes

    International Nuclear Information System (INIS)

    The role of radiation belt electron precipitation into the Earth's atmosphere at middle geomagnetic latitudes is studied. First, the process of pitch angle scattering of energetic electrons in the radiation belts is modeled, and the flux angular distributions are obtained for all pitch angles, including the atmospheric bounce loss cone. This determines the angular distribution of the precipitating fluxes. Secondly, the interaction of these fluxes with the ambient atmospheric constituents is simulated, using the Fokker-Planck method; and the rate of energy deposition in the atmosphere is calculated at any given height. This gives rise to a significant rate of ion pair production in the lower ionosphere. Thirdly, the influence of this precipitation induced ionization on the structure and composition of the ionospheric D-region is modeled. Two specific classes of electron precipitation are studied; one is the quiet time ''drizzle'' occurring in the absence of geomagnetic disturbances; the second is the storm-time precipitation during the recovery phase of major geomagnetic storms with its substantial impact on the lower ionosphere. Computations are furthermore carried out for geomagnetically quiet times, and the results indicate that the electron precipitation can provide the dominant nocturnal ionization source for the D-region in a narrow belt of geomagnetic latitudes corresponding to the inner edge of the outer radiation zone (L approximately 4 to 5; Λ approximately 600 to 650) with ion pair production rates typically between 0.1 and 1 ion pair cm-3 sec-1 from about 60 to 90 kilometers at L = 5. (U.S.)

  20. Precipitation kinetics of Si in aluminium alloys

    International Nuclear Information System (INIS)

    The precipitation kinetics of Si in an Al-1.7 wt.%Si alloy after different thermal treatments has been studied by means of transmission electron microscopy (TEM), dilatometry and differential scanning calorimetry (DSC). The results obtained are explained by a model based on simple nucleation and growth/dissolution laws and are compared with measured precipitate size distributions. The evolution of precipitates in water-quenched samples during linear heating depicts the exothermic formation of platelets and globular Si precipitates (200-300 deg. C). The endothermal dissolution of Si platelets starts at lower temperatures than that of the globular precipitates. Coarsening and finally dissolution of globular precipitates is observed with increasing temperature. Samples slowly cooled from the solution treatment temperature present mostly globular precipitates, which are nucleated during cooling. Here, an exothermal effect related to the growth of Si precipitates increasing their volume fraction is observed at relatively high temperatures (350-460 deg. C) during linear heating. The formed precipitates are stable up to ∼460 deg. C, where the modelled critical radius becomes bigger than most of the Si precipitates formed so far

  1. A Plan for Measuring Climatic Scale Global Precipitation Variability: The Global Precipitation Mission

    Science.gov (United States)

    Smith, Eric A.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The outstanding success of the Tropical Rainfall Measuring Mission (TRMM) stemmed from a near flawless launch and deployment, a highly successful measurement campaign, achievement of all original scientific objectives before the mission life had ended, and the accomplishment of a number of unanticipated but important additional scientific advances. This success and the realization that satellite rainfall datasets are now a foremost tool in the understanding of decadal climate variability has helped motivate a comprehensive global rainfall measuring mission, called 'The Global Precipitation Mission' (GPM). The intent of this mission is to address looming scientific questions arising in the context of global climate-water cycle interactions, hydrometeorology, weather prediction, the global carbon budget, and atmosphere-biosphere-cryosphere chemistry. This paper addresses the status of that mission currently planed for launch in the early 2007 time frame. The GPM design involves a nine-member satellite constellation, one of which will be an advanced TRMM-like 'core' satellite carrying a dual-frequency Ku-Ka band radar (df-PR) and a TMI-like radiometer. The other eight members of the constellation can be considered drones to the core satellite, each carrying some type of passive microwave radiometer measuring across the 10.7-85 GHz frequency range, likely based on both real and synthetic aperture antenna technology and to include a combination of new lightweight dedicated GPM drones and both co-existing operational and experimental satellites carrying passive microwave radiometers (i.e., SSM/l, AMSR, etc.). The constellation is designed to provide a minimum of three-hour sampling at any spot on the globe using sun-synchronous orbit architecture, with the core satellite providing relevant measurements on internal cloud precipitation microphysical processes. The core satellite also enables 'training' and 'calibration' of the drone retrieval process. Additional

  2. Springtime precipitation effects on the abundance of fluorescent biological aerosol particles and HULIS in Beijing

    Science.gov (United States)

    Yue, Siyao; Ren, Hong; Fan, Songyun; Sun, Yele; Wang, Zifa; Fu, Pingqing

    2016-07-01

    Bioaerosols and humic-like substances (HULIS) are important components of atmospheric aerosols, which can affect regional climate by acting as cloud condensation nuclei and some of which can damage human health. Up to date, release of bioaerosols and HULIS initiated by precipitation is still poorly understood. Here we present different release processes for bioaerosols, non-bioaerosols and HULIS during a precipitation event in Beijing, China. Large fungal-spore-like aerosols were emitted at the onset and later weak stage of precipitation, the number concentration of which increased by more than two folds, while the number concentration of bacteria-like particles doubled when the precipitation strengthened. Besides, a good correlation between protein-like substances that were measured simultaneously by on-line and off-line fluorescence techniques consolidated their applications to measure bioaerosols. Furthermore, our EEM results suggest that the relative contribution of water-soluble HULIS to microbial materials was enhanced gradually by the rain event.

  3. ANNUAL VARIATION OF AVERAGE MONTHLY PRECIPITATION AMOUNTS AT THE BOTOŞANI METEOROLOGICAL STATION

    Directory of Open Access Journals (Sweden)

    Liviu Apostol

    2011-10-01

    Full Text Available The atmospheric precipitations present a great variability and discontinuity in space and time, their distribution and regimen depending, equally,on the dynamic, physical-geographical and radiative factors. In Romania, precipitations generally have a continental character, with a maximum in June and minimum in January – February. However, from the analysis of monthly multiannual values of the precipitations quantities registered in the period 1962-2009 at the Botosani station, as a consequence of the intensification of the cyclonic activities in the months of July of the last 12 years, but also of the intensification of the thermal convection in this month, results that the highest value is registered in July(94,2 mm. The quantitative difference between this month and June is notable (9,8mm. On the other hand, the urbanization processes and human activities determined, in the last years, an increase of the number of condensation nuclei and an increase of precipitations frequency

  4. Local control on precipitation in a fully coupled climate-hydrology model

    DEFF Research Database (Denmark)

    Larsen, Morten A. D.; Christensen, Jens H.; Drews, Martin;

    2016-01-01

    simulations of precipitation often exhibit substantial biases that affect the reliability of future projections. Here we demonstrate how a regional climate model (RCM) coupled to a distributed hydrological catchment model that fully integrates water and energy fluxes between the subsurface, land surface......The ability to simulate regional precipitation realistically by climate models is essential to understand and adapt to climate change. Due to the complexity of associated processes, particularly at unresolved temporal and spatial scales this continues to be a major challenge. As a result, climate......, plant coverand the atmosphere, enables a realistic representation of local precipitation. Substantial improvements in simulated precipitation dynamics on seasonal and longer time scales is seen for a simulation period of six years and can be attributed to a more complete treatment of hydrological sub...

  5. The effect of a giant wind farm on precipitation in a regional climate model

    International Nuclear Information System (INIS)

    The Weather Research and Forecasting (WRF) model is employed as a nested regional climate model to study the effect of a giant wind farm on warm-season precipitation in the eastern two-thirds of the USA. The boundary conditions for WRF are supplied by 62 years of NCEP/NCAR (National Center for Environmental Prediction/National Center for Atmospheric Research) global reanalysis. In the model, the presence of a mid-west wind farm, either giant or small, can have an enormous impact on the weather and the amount of precipitation for one season, which is consistent with the known sensitivity of long-term weather forecasts to initial conditions. The effect on climate is less strong. In the average precipitation of 62 warm seasons, there is a statistically significant 1.0% enhancement of precipitation in a multi-state area surrounding and to the south-east of the wind farm.

  6. CMORPH 8 Km: A Method that Produces Global Precipitation Estimates from Passive Microwave and Infrared Data at High Spatial and Temporal Resolution

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A new technique is presented in which half-hourly global precipitation estimates derived from passive microwave satellite scans are propagated by motion vectors...

  7. Prediction of winter precipitation over northwest India using ocean heat fluxes

    Science.gov (United States)

    Nageswararao, M. M.; Mohanty, U. C.; Osuri, Krishna K.; Ramakrishna, S. S. V. S.

    2015-12-01

    The winter precipitation (December-February) over northwest India (NWI) is highly variable in terms of time and space. The maximum precipitation occurs over the Himalaya region and decreases towards south of NWI. The winter precipitation is important for water resources and agriculture sectors over the region and for the economy of the country. It is an exigent task to the scientific community to provide a seasonal outlook for the regional scale precipitation. The oceanic heat fluxes are known to have a strong linkage with the ocean and atmosphere. Henceforth, in this study, we obtained the relationship of NWI winter precipitation with total downward ocean heat fluxes at the global ocean surface, 15 regions with significant correlations are identified from August to November at 90 % confidence level. These strong relations encourage developing an empirical model for predicting winter precipitation over NWI. The multiple linear regression (MLR) and principal component regression (PCR) models are developed and evaluated using leave-one-out cross-validation. The developed regression models are able to predict the winter precipitation patterns over NWI with significant (99 % confidence level) index of agreement and correlations. Moreover, these models capture the signals of extremes, but could not reach the peaks (excess and deficit) of the observations. PCR performs better than MLR for predicting winter precipitation over NWI. Therefore, the total downward ocean heat fluxes at surface from August to November are having a significant impact on seasonal winter precipitation over the NWI. It concludes that these interrelationships are more useful for the development of empirical models and feasible to predict the winter precipitation over NWI with sufficient lead-time (in advance) for various risk management sectors.

  8. Land use change suppresses precipitation

    Directory of Open Access Journals (Sweden)

    W. Junkermann

    2009-05-01

    Full Text Available A feedback loop between regional scale deforestation and climate change was investigated in an experiment using novel, small size airborne platforms and instrument setups. Experiments were performed in a worldwide unique natural laboratory in Western Australia, characterized by two adjacent homogeneous observation areas with distinctly different land use characteristics. Conversion of several ten thousand square km of forests into agricultural land began more than a century ago. Changes in albedo and surface roughness and the water budget of soil and the planetary boundary layer evolved over decades. Besides different meteorology we found a significant up to now overseen source of aerosol over the agriculture. The enhanced number of cloud condensation nuclei is coupled through the hydrological groundwater cycle with deforestation. Modification of surface properties and aerosol number concentrations are key factors for the observed reduction of precipitation. The results document the importance of aerosol indirect effects on climate due to nanometer size biogenic aerosol and human impact on aerosol sources.

  9. A study of the relationship between cloud-to-ground lightning and precipitation in the convective weather system in China

    Directory of Open Access Journals (Sweden)

    Y. Zhou

    Full Text Available In this paper, the correlation between cloud-to-ground (CG lightning and precipitation has been studied by making use of the data from weather radar, meteorological soundings, and a lightning location system that includes three direction finders about 40 km apart from each other in the Pingliang area of east Gansu province in P. R. China. We have studied the convective systems that developed during two cold front processes passing over the observation area, and found that the CG lightning can be an important factor in the precipitation estimation. The regression equation between the average precipitation intensity (R and the number of CG lightning flashes (L in the main precipitation period is R = 1.69 ln (L - 0.27, and the correlation coefficient r is 0.86. The CG lightning flash rate can be used as an indicator of the formation and development of the convective weather system. Another more exhaustive precipitation estimation method has been developed by analyzing the temporal and spatial distributions of the precipitation relative to the location of the CG lightning flashes. Precipitation calculated from the CG lightning flashes is very useful, especially in regions with inadequate radar cover.

    Key words. Meteorology and atmospheric dynamics (atmospheric electricity; lightning; precipitation

  10. Variation of precipitation in Langtang Valley,Himalayas

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Xinping

    2001-01-01

    [1]Araguas-Araguas ,L Froehlich K Rozanski JK Stable isotoe composition over aSla Journal of Gepohpsicrch ,1998,103(28):721-742[2]Dansgaard W Stabnle isotopes in precipitation Tellus ,1994,16(4):436-468[3]Fricke H C O,Neil J R Thje correlation between O/O ratios of meroric water anbd surfacr temperature ,its use in inverstigating terrestiral cleimate chang over geologic time Earch and Planetary Science Letters ,1999,170:181-196[4]Rozanski ,K Araguas L Gonfiantini R R ealtion between long-term trensd of ocuyen -18 isotope compsition of pre-ciptayion and climate Scinese ,1992,258:981-985[5]Jouzel, J., Froehlich, K., Schotterer, U, Deuterium and oxyen-18 in present-day precipitation: data and modeling, Journal of Hydrological Sciences, 1997, 42(5): 747-763.[6]Zhang, X. P., Shi, Y. F., Yao, T. D., Variational features of precipitation δ 18O in Northeast Qinghai-Tibet Plateau. Science in China. Set. B, 1995,38(7): 854-864.[7]Dansgaard, W., The abundance of 18O in atmospheric water and water vapor, Tellus, 1953,5(4): 461-469.[8]Jouzel. J., Isotopes in cloud: multiphase and multistage condensation process, in Handbook of Environmental Isotope Geochemistry (2), Amsterdam-Oxford-New York: Elsevier Scientific Publishing Company, 1986, 61-112.[9]Jouzel, J., Russell, G. L., Suozzo, R. J. et al., Simulations of HDO and H218O atmospheric cycles using the NASA GISS general circulation model: the seasonal cycle for present-day conditions, Journal of Geophysical Research, 1987,92( 14):739-760.[10]Zhang, X. P., Variation of dδ 18O/dT in precipitation in the Qinghai-Xizang Plateau, Chinese Geographical Science, 1997,7: 339-346.[11]Siegenthaler, U., Oeschger, H., Correlation of 18O in precipitation with temperature and altitude, Nature, 1980, 285:314319.[12]Rozanski, K, Johnson, S. J., Schotterer, U. et al., Reconstruction of past climates from stable isotope records of palaeo-precipitation preserved in continental archives, Journal of

  11. Precipitation Efficiency in the Tropical Deep Convective Regime

    Science.gov (United States)

    Li, Xiaofan; Sui, C.-H.; Lau, K.-M.; Lau, William K. M. (Technical Monitor)

    2001-01-01

    Precipitation efficiency in the tropical deep convective regime is analyzed based on a 2-D cloud resolving simulation. The cloud resolving model is forced by the large-scale vertical velocity and zonal wind and large-scale horizontal advections derived from TOGA COARE for a 20-day period. Precipitation efficiency may be defined as a ratio of surface rain rate to sum of surface evaporation and moisture convergence (LSPE) or a ratio of surface rain rate to sum of condensation and deposition rates of supersaturated vapor (CMPE). Moisture budget shows that the atmosphere is moistened (dryed) when the LSPE is less (more) than 100 %. The LSPE could be larger than 100 % for strong convection. This indicates that the drying processes should be included in cumulus parameterization to avoid moisture bias. Statistical analysis shows that the sum of the condensation and deposition rates is bout 80 % of the sum of the surface evaporation rate and moisture convergence, which ads to proportional relation between the two efficiencies when both efficiencies are less han 100 %. The CMPE increases with increasing mass-weighted mean temperature and creasing surface rain rate. This suggests that precipitation is more efficient for warm environment and strong convection. Approximate balance of rates among the condensation, deposition, rain, and the raindrop evaporation is used to derive an analytical solution of the CMPE.

  12. Consequences of more extreme precipitation regimes for terrestrial ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, Alan [Colorado State University, Fort Collins; Beier, Claus [Riso National Laboratory, Roskilde, Denmark; Briske, David [Texas A& M University; Classen, Aimee T [ORNL; Luo, Yiqi [University of Oklahoma; Reichstein, Markus [Max Planck Institute for Biogeochemistry; Smith, Melinda D [Yale University; Smith, Stanley D [University of Nevada, Las Vegas; Bell, Jesse E [University of Oklahoma; Fay, Philip [ORNL; Heisler, Jana A [Colorado State University, Fort Collins; Leavitt, Steven W [unknown; Sherry, Rebecca [University of Oklahoma; Smith, Ben [unknown; Weng, Ensheng [University of Oklahoma, Norman; Norby, Richard J [ORNL

    2008-09-01

    Amplification of the hydrological cycle, as a consequence of global warming, is forecast to be manifest not only by alterations in total annual precipitation, but also through more extreme precipitation regimes characterized by larger rainfall events and more severe intervening drought periods. Based on past studies and theory, we present a conceptual framework for predicting the consequences of this projected change in intra-annual rainfall patterns for terrestrial ecosystems arrayed along a broad gradient in water availability. More extreme rainfall regimes are predicted to increase the occurrence of periodic soil water stress in mesic ecosystems due to prolonged dry periods between rainfall events. In contrast, xeric ecosystems may exhibit the opposite response because a shift to a greater proportion of rainfall delivered in large precipitation events will result in reduced proportional evaporative losses per storm event and greater soil water storage, alleviating soil water stress for longer periods of time. Hydric ecosystems may experience reduced periods of anoxia if intervals between rainfall events increase. This contingent effect of the overall soil water balance on ecosystem responses will likely cascade through all hierarchical levels of ecological processes and interact in ways currently unknown with related global change drivers such as elevated atmospheric temperatures and CO2 concentrations. Thus, multi-factor comparative experiments and systems modeling approaches are needed to more fully understand and forecast the potential ecological consequences of this underappreciated aspect of climate change.

  13. A global assessment of precipitation chemistry and deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity and pH, and phosphorus

    OpenAIRE

    Vet, Robert; Pienaar, Jacobus J.; Artz, Richard S.; Carou, Silvina; Shaw, Mike; Ro, Chul-Un; Aas, Wenche

    2014-01-01

    A global assessment of precipitation chemistry and deposition has been carried out under the direction of the World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) Scientific Advisory Group for Precipitation Chemistry (SAG-PC). The assessment addressed three questions: (1) what do measurements and model estimates of precipitation chemistry and wet, dry and total deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity, and phosphorus show glob...

  14. Impact of Aerosols on Convective Clouds and Precipitation

    Science.gov (United States)

    Tao, Wei-Kuo; Chen, Jen-Ping; Li, Zhanqing; Wang, Chien; Zhang, Chidong; Li, Xiaowen

    2012-01-01

    Aerosols are a critical.factor in the atmospheric hydrological cycle and radiation budget. As a major agent for clouds to form and a significant attenuator of solar radiation, aerosols affect climate in several ways. Current research suggests that aerosols have a major impact on the dynamics, microphysics, and electrification properties of continental mixed-phase convective clouds. In addition, high aerosol concentrations in urban environments could affect precipitation variability by providing a significant source of cloud condensation nuclei (CCN). Such pollution . effects on precipitation potentially have enormous climatic consequences both in terms of feedbacks involving the land surface via rainfall as well as the surface energy budget and changes in latent heat input to the atmosphere. Basically, aerosol concentrations can influence cloud droplet size distributions, the warm-rain process, the cold-rain process, cloud-top heights, the depth of the mixed-phase region, and the occurrence of lightning. Recently, many cloud resolution models (CRMs) have been used to examine the role of aerosols on mixed-phase convective clouds. These modeling studies have many differences in terms of model configuration (two- or three-dimensional), domain size, grid spacing (150-3000 m), microphysics (two-moment bulk, simple or sophisticated spectral-bin), turbulence (1st or 1.5 order turbulent kinetic energy (TKE)), radiation, lateral boundary conditions (i.e., closed, radiative open or cyclic), cases (isolated convection, tropical or midlatitude squall lines) and model integration time (e.g., 2.5 to 48 hours). Among these modeling studies, the most striking difference is that cumulative precipitation can either increase or decrease in response to higher concentrations of CCN. In this presentation, we review past efforts and summarize our current understanding of the effect of aerosols on convective precipitation processes. Specifically, this paper addresses the following topics

  15. Long-term regional precipitation disparity in northwestern China and its driving forces

    Directory of Open Access Journals (Sweden)

    H. F. Lee

    2014-08-01

    Full Text Available Subject to the unique physical setting of northwestern China (NW China, precipitation in the region is characterized by salient regional differences. Yet, the long-term regional precipitation disparity in NW China still remains insufficiently-explored. In the present study, we base on historical documentation to reconstruct the precipitation indices of two macro regions in NW China between AD580–1979 to address the following issues: (1 determine the multi-decadal to centennial regional precipitation disparity in NW China, a topic which has not been systematically examined in previous paleo-climate/paleo-environment studies; and (2 find the major driving forces behind it. Wavelet analysis, which is ideal for analyzing non-stationary systems, is applied. Our results show that there is significant regional discrepancy of precipitation change in NW China over extended period. Although there is significant association between the regional precipitation disparity in NW China and various modes of atmospheric circulation, the association is characterized by a regime shift during the transition from the Medieval Warm Period to the Little Ice Age. Most importantly, the low-frequency cycle of the El Niño–Southern Oscillation is found to be the most prominent pacemaker of regional precipitation disparity in NW China at the multi-decadal to centennial timescales. Our findings help to demonstrate which atmospheric circulation is primarily responsible for the long-term regional precipitation disparity in NW China, which may have important implications for water resource management in NW China in the near future.

  16. The impact of energetic electron precipitation on mesospheric hydroxyl during a year of solar minimum

    Science.gov (United States)

    Zawedde, Annet Eva; Nesse Tyssøy, Hilde; Hibbins, Robert; Espy, Patrick J.; Ødegaard, Linn-Kristine Glesnes; Sandanger, Marit Irene; Stadsnes, Johan

    2016-06-01

    In 2008 a sequence of geomagnetic storms occurred triggered by high-speed solar wind streams from coronal holes. Improved estimates of precipitating fluxes of energetic electrons are derived from measurements on board the NOAA/POES 18 satellite using a new analysis technique. These fluxes are used to quantify the direct impact of energetic electron precipitation (EEP) during solar minimum on middle atmospheric hydroxyl (OH) measured from the Aura satellite. During winter, localized longitudinal density enhancements in the OH are observed over northern Russia and North America at corrected geomagnetic latitudes poleward of 55°. Although the northern Russia OH enhancement is closely associated with increased EEP at these longitudes, the strength and location of the North America enhancement appear to be unrelated to EEP. This OH density enhancement is likely due to vertical motion induced by atmospheric wave dynamics that transports air rich in atomic oxygen and atomic hydrogen downward into the middle atmosphere, where it plays a role in the formation of OH. In the Southern Hemisphere, localized enhancements of the OH density over West Antarctica can be explained by a combination of enhanced EEP due to the local minimum in Earth's magnetic field strength and atmospheric dynamics. Our findings suggest that even during solar minimum, there is substantial EEP-driven OH production. However, to quantify this effect, a detailed knowledge of where and when the precipitation occurs is required in the context of the background atmospheric dynamics.

  17. Experimental study of diffuse auroral precipitations

    International Nuclear Information System (INIS)

    First chapter is devoted to low energy electron precipitation in the evening sector of the auroral magnetosphere, during quiet and disturbed magnetic periods. Four subjects are studied in detail: the latitude distribution of the varied auroral forms and their relations to external magnetosphere; the time coefficients related to precipitations, the form and the dynamic of the diffuse precipitation equatorial frontier; the precipitation effect on the ionosphere concentration. The last part of the chapter shows that the plasma convection in the magnetosphere, associated to wave-particle interactions near the equatorial accounts for the principal characteristics of the evening sector diffuse electronic precipitations. The second chapter deals with subauroral precipitations of low energy ions, after the magnetospheric substorms, in the high latitude regions of the morning sector

  18. Estimating Global Precipitation for Science and Application

    Science.gov (United States)

    Huffman, George J.

    2013-01-01

    Over the past two decades there has been vigorous development in the satellite assets and the algorithms necessary to estimate precipitation around the globe. In particular the highly successful joint NASAJAXA Tropical Rainfall Measuring Mission (TRMM) and the upcoming Global Precipitation Measurement (GPM) mission, also joint between NASA and JAXA, have driven these issues. At the same time, the long-running Global Precipitation Climatology Project (GPCP) continues to extend a stable, climate-oriented view of global precipitation. This talk will provide an overview of these projects and the wider international community of precipitation datasets, sketch plans for next-generation products, and provide some examples of the best use for the different products. One key lesson learned is that different data sets are needed to address the variety of issues that need precipitation data, including detailed 3-D views of hurricanes, flash flood forecasting, drought analysis, and global change.

  19. Radiogenic silicon precipitates in neutron irradiated aluminum

    International Nuclear Information System (INIS)

    A theory of precipitation of radiogenic Si in Al is developed. The aim of this study is to predict quantitatively the variation of microstructural parameters such as precipitates number and sizes dependently on irradiation parameters. Analogy with deposition of thin films and formation of silver halides is discussed. A model for the precipitation of radiogenic Si in Al is developed on the basis of the theory of Ostwald-ripening in precipitation processes with constant rate addition of monomers. The model predicts that after the precipitation process enters the 'late' stage, the number of precipitates depends only on the ratio between the thermal and fast neutron fluxes but not on the absolute values of flux and fluence. A quantitative interpretation of the spectral effect, suggested by Farrell [Mater. Res. Soc. Symp. Proc. 373 (1995) 165] is given. The predictions of the model are compared with experimental results

  20. Modelling monthly precipitation with circulation weather types for a dense network of stations over Iberia

    Science.gov (United States)

    Cortesi, N.; Trigo, R. M.; Gonzalez-Hidalgo, J. C.; Ramos, A. M.

    2013-02-01

    Precipitation over the Iberian Peninsula (IP) is highly variable and shows large spatial contrasts between wet mountainous regions to the north, and dry regions in the inland plains and southern areas. In this work, we modelled the relationship between atmospheric circulation weather types (WTs) and monthly precipitation for the wet half of the year (October to May) using a 10 km grid derived from a high-density dataset for the IP (3030 precipitation series, overall mean density one station each 200 km2). We detected two spatial gradients in the relationship between WTs and precipitation. The percentage of monthly precipitation explained by WTs varies from northwest (higher variance explained) to southeast (lower variance explained). Additionally, in the IP the number of WTs that contribute significantly to monthly precipitation increase systematically from east to west. Generally speaking, the model performance is better to the west than to the east where the WTs approach produce the less accurate results. We applied the WTs modelling approach to reconstruct the long-term precipitation time series for three major stations of Iberia (Lisbon, Madrid, Valencia).

  1. Projected precipitation changes in South America: a dynamical downscaling within CLARIS

    Energy Technology Data Exchange (ETDEWEB)

    Soerensson, Anna A. [Centra de Investigaciones del Mar y la Atmosfera, CONICET/UBA, Buenos Aires (Argentina); Menendez, Claudio G. [Centra de Investigaciones del Mar y la Atmosfera, CONICET/UBA, Buenos Aires (Argentina); Dept. de Ciencias de la Atmosfera y los Oceanos, FCEN, UBA, Buenos Aires (Argentina); Ruscica, Romina; Alexander, Peter [Dept. de Fisica, FCEN, UBA, Buenos Aires (Argentina); Samuelsson, Patrick; Willen, Ulrika [Rossby Centre, SMHI, Norrkoeping (Sweden)

    2010-06-15

    Responses of precipitation seasonal means and extremes over South America in a downscaling of a climate change scenario are assessed with the Rossby Centre Regional Atmospheric Model (RCA). The anthropogenic warming under A1B scenario influences more on the likelihood of occurrence of severe extreme events like heavy precipitation and dry spells than on the mean seasonal precipitation. The risk of extreme precipitation increases in the La Plata Basin with a factor of 1.5-2.5 during all seasons and in the northwestern part of the continent with a factor 1.5-3 in summer, while it decreases in central and northeastern Brazil during winter and spring. The maximum amount of 5-days precipitation increases by up to 50% in La Plata Basin, indicating risks of flooding. Over central Brazil and the Bolivian lowland, where present 5-days precipitation is higher, the increases are similar in magnitude and could cause less impacts. In southern Amazonia, northeastern Brazil and the Amazon basin, the maximum number of consecutive dry days increases and mean winter and spring precipitation decreases, indicating a longer dry season. In the La Plata Basin, there is no clear pattern of change for the dry spell duration. (orig.)

  2. A global ETCCDI based precipitation climatology from satellite and rain gauge measurements

    Science.gov (United States)

    Dietzsch, Felix; Andersson, Axel; Schröder, Marc; Ziese, Markus; Becker, Andreas

    2016-04-01

    The project framework MiKlip ("Mittelfristige Klimaprognosen") is focused onto the development of an operational forecast system for decadal climate predictions. The objective of the "Daily Precipitation Analysis for the validation of Global medium-range Climate predictions Operationalized" (DAPAGLOCO) project, is the development and operationalization of a global precipitation dataset for forecast validation of the MPI-ESM experiments used in MiKlip. The dataset is a combination of rain gauge measurement data over land and satellite-based precipitation retrievals over ocean. Over land, gauge data from the Global Precipitation Climatology Centre (GPCC) at Deutscher Wetterdienst (DWD) are used. Over ocean, retrievals from the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS) dataset are used as data source. The currently available dataset consists of 21 years of data (1988-2008) and has a spatial resolution of 1°. So far, the MiKlip forecast validation is based upon the Expert Team on Climate Change and Detection Indices (ETCCDI). These indices focus on precipitation extrema in terms of spell durations, percentiles, averaged precipitation amounts and further more. The application of these indices on the DAPAGLOCO dataset in its current state delivers insight into the global distribution of precipitation characteristics and extreme events. The resulting global patterns of these characteristics and extrema are the main objective of the presentation.

  3. Modelling monthly precipitation with circulation weather types for a dense network of stations over Iberia

    Directory of Open Access Journals (Sweden)

    N. Cortesi

    2013-02-01

    Full Text Available Precipitation over the Iberian Peninsula (IP is highly variable and shows large spatial contrasts between wet mountainous regions to the north, and dry regions in the inland plains and southern areas. In this work, we modelled the relationship between atmospheric circulation weather types (WTs and monthly precipitation for the wet half of the year (October to May using a 10 km grid derived from a high-density dataset for the IP (3030 precipitation series, overall mean density one station each 200 km2. We detected two spatial gradients in the relationship between WTs and precipitation. The percentage of monthly precipitation explained by WTs varies from northwest (higher variance explained to southeast (lower variance explained. Additionally, in the IP the number of WTs that contribute significantly to monthly precipitation increase systematically from east to west. Generally speaking, the model performance is better to the west than to the east where the WTs approach produce the less accurate results. We applied the WTs modelling approach to reconstruct the long-term precipitation time series for three major stations of Iberia (Lisbon, Madrid, Valencia.

  4. FORSGC network for isotopes in precipitation over the Monsoon Asia

    International Nuclear Information System (INIS)

    Full text: The GNIP project provides the monthly data of stable isotopes in precipitation all over the world. For the validation of atmospheric water cycle by reanalysis datasets or GCM simulations, however, there are a few stations in Asia. Also, spatial and temporal variability of the stable isotope composition of precipitation in the Asia Pacific region was discussed based on the GNIP monthly dataset. However, the relationship between isotope signature of precipitation and climate in Tropics is not well understood, because the daily isotopic data in precipitation is limited. Since 2000, the isotope group of the Frontier Observational Research System for Global Change (FORSGC) had been collecting the daily precipitation samples for stable isotopes over the Monsoon Asia, such as Siberia (3 stations), Tibetan Plateau (10 stations), Nepal (5 stations), Thailand (3 stations), Indonesia (5 stations), and Palau Island (1 station). In this study, we will introduce the FORSGC network for stable isotopes in precipitation database and show the short-term (monthly and daily) variability of precipitation isotopes observed in Thailand and Indonesia and so on. The daily rainfall samples were collected during August to December 2001 at ChiangMai, Bangkok and Phuket stations in Thailand. These stations showed similar monthly variability in Oxygen-18, and most ranged from -15 per mille to 0 per mille. There were increasing trends in August and November, while decreasing trend in September. Daily variability, however, showed a different trend. A depletion of early-August at ChiangMai and a sudden enrichment around 10 October at Phuket were appeared. Considering relationships between Oxygen-18 and precipitation amount, there were positive correlations in three stations by the monthly basis. In general, isotopic compositions are heavy in low precipitation and light in high precipitation caused by the amount effect. The precipitation was small from August to early September and large

  5. Spatial Distribution of Precipitation in Lithuania

    Directory of Open Access Journals (Sweden)

    Viktorija Grušaitė

    2011-04-01

    Full Text Available Analysis is based on a 36-year record (1971–2006 of daily precipitation at 17 meteorological stations throughout Lithuania. The obtained data was used to investigate the spatial properties of the precipitation fields of monthly decadals (10-days. The average, minimum and maximum correlation coefficients of decadals were estimated. A spatial correlation of precipitation was created among all meteorological stations in Lithuania.Article in Lithuanian

  6. Spatial Distribution of Precipitation in Lithuania

    OpenAIRE

    Viktorija Grušaitė

    2011-01-01

    Analysis is based on a 36-year record (1971–2006) of daily precipitation at 17 meteorological stations throughout Lithuania. The obtained data was used to investigate the spatial properties of the precipitation fields of monthly decadals (10-days). The average, minimum and maximum correlation coefficients of decadals were estimated. A spatial correlation of precipitation was created among all meteorological stations in Lithuania.Article in Lithuanian

  7. [Characteristics of Stable Isotopes in Precipitation and Their Moisture Sources in Mengzi Region, Southern Yunnan].

    Science.gov (United States)

    Li, Guang; Zhang, Xin-ping; Xu, You-peng; Song, Song; Wang, Yue-feng; Ji, Xiao-min; Xiang, Jie; Yang, Jie

    2016-04-15

    The δD and δ¹⁸O values in precpitation have disciplinary variations, and they have close connections with meteorological parameters and moisture sources. Based on the continuously collected precipitation samples in Mengzi from Jan. 2009 to Dec. 2011, the reanalysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF) and the National Centre for Environmental Prediction/National Centre for Atmospheric Research (NCEP/NCAR), and the Hybrid Single-Particle Lagrangian Integrated Trajectory for 4.8 (HYSPLIT_4.8) model, we analyzed the variations of δD and δ¹⁸O in precipitation at synoptic scale in Mengzi, and the relations between δ¹⁸O in precipitation and air temperature, δ¹⁸O in precipitation and amount, δ¹⁸O in precipitation and wind speed, δ¹⁸O in precipitation and moisture sources. The results showed that the variations of δD and δ¹⁸O values in precipitation exhibited remarkable seasonal variability. The stable isotopic values in precipitation were higher during dry season than those during wet season. The relations between δ¹⁸O in precipitation and air temperature, δ¹⁸O in precipitation and amount indicated significant negative correlations. However, it exhibited significant positive correlation between precipitation δ¹⁸O and wind speed at different pressure levels (300 hPa, 500 hPa, 700 hPa, and 800 hPa), and this result indicated that the wind speed was an important influencing factor for the variations of precipitation δ¹⁸O. With the increasing rainfall levels, the intercept and slope of meteoric water line also increased, and this phenomenon suggested that there was a secondary evaporation effect under sub-cloud in stable isotopes of precipitation. The backward trajectory model showed that the main moisture sources during dry season came from the westerly and the inland. However, during wet season, the remote ocean vapor was the main moisture source in Mengzi, and the δ¹⁸O values in

  8. Observation of solid precipitation using satellite gravity

    Science.gov (United States)

    Seo, K.; Waliser, D. E.; Ryu, D.; Tian, B.; Kim, B.

    2009-12-01

    Understanding hydrological processes in the arctic region and their variation are emerging and important issues in the association with global climate changes. Solid precipitation is particularly important because it plays a major role in controlling the winter hydrological cycle and spring discharge. Nevertheless, observations of winter snowfall in high latitudes is challenging due to sharply decreasing numbers of precipitation gauges and gauge measurement biases. In addition, conventional satellite methods that work well in low-latitudes are unsuitable for the high latitude conditions. In this study, we present a new method of estimating winter snowfall in the arctic region with GRACE time varying gravity measurements. In northern high latitudes, it is very cold in winter, and thus solid precipitation accumulates with very limited melting and evapotranspiration. Therefore, observed gravity increments during winter mainly result from solid precipitation. We estimate amount of solid precipitation during winter (DJF) from four major arctic basins, Mackenzie, Lena, Yenisei and Ob. New estimates using satellite gravity are compared to global satellite and reanalysis precipitation products , which are GPCP, CMAP, NCEP/NCAR, ECMWF and JCDAS. GRACE-based estimates of snowfall are very close to those of CMAP, ECMWF and JCDAS. We extend the methodology to examine spatial distribution of solid precipitation in the pan-arctic land areas, which shows a good agreement with JCDAS. This new measurement of solid precipitation can provide an altogether new form of observations for hydrological cycle research studies, model and precipitation product evaluation and data assimilation efforts.

  9. Water Vapour Content of the Atmosphere in Relation to Surface Humidity

    Directory of Open Access Journals (Sweden)

    N. C. Majumdar

    1977-10-01

    Full Text Available The theoretical relationship between precipitate water vapour in the atmosphere & surface humidity has been investigated. By introducing the concept of a lapse parameter alpha, a method has been devised for estimation of precipitable water vapour. Results have been compared for six Indian Stations for which upper air data were available.

  10. New progress of research on water cycle in atmosphere in China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    New progresses are introduced briefly about the water cycle study on atmosphere of China made in recent years. The introduction includes eight aspects as follows: 1) precipitation characteristics, 2) stability of climatic system, 3) precipitation sensitive region, 4) regional evaporation and evapotranspiration, 5) water surface evaporation, 6) vegetation transpiration, 7) cloud physics, and 8) vapor source.

  11. On the Annual Cycle of Central South-West Asia precipitation in GCMs: an Analysis of AMIP Simulation Results

    Science.gov (United States)

    Malik, K. M.; Taylor, P.; Szeto, K.

    2009-12-01

    This study evaluates simulations of precipitation patterns over the Central South-West Asia region (25-40N and 45-75E) by using results from the Atmospheric Model Inter-comparison Project (AMIP). Annual and monthly spatial precipitation fields produced by a subset of 13 currently available AMIP model experiments are evaluated for the region and compared with GPCC (Global Precipitation Climatology Centre) monthly precipitation data for the period of 1979-2001. GPCC precipitation data are available with 0.5 degree resolution and correlate with observational precipitation data with a correlation factor of 0.953. The models show large variations in their ability to capture the seasonal precipitation, although spatial correlations indicate that some of the models simulate the pattern of GPCC precipitation fields fairly well. Some models cannot capture the convective precipitation in the region that occurs during spring (March-April) and fall (Sept-Oct). Relative to the GPCC data most of the models predicted well in winter whereas some models cannot adequately capture the summer (monsoon) precipitation which enters the domain from east. On the spatial scales of the selected region, there is little consistent evidence that points to any specific feature as an indicator of model performance. None of the obvious candidates such as horizontal resolution, convective closure schemes, or land surface schemes are reliable discriminators of a models ability to simulate precipitation accurately. Horizontal resolution effects are apparent in the inter-mountain region, where high resolution models do better that low resolution models. However, there is not enough evidence to produce reliable simulation on this basis. Correlation coefficients of observed precipitation with model output can be improved by using ensemble averaged precipitation from several models.

  12. Optical Signatures of Lightning-induced Electron Precipitation (Invited)

    Science.gov (United States)

    Marshall, R. A.; Bortnik, J.; Lehtinen, N. G.

    2010-12-01

    The electromagnetic pulse (EMP) from an intense lightning discharge propagates primarily in the waveguide formed between the Earth and the ionosphere, but a fraction of its energy leaks through the ionosphere and propagates as whistler-mode waves in the inner magnetosphere. In the equatorial region, these whistlers cause pitch-angle and energy scattering of trapped energetic electrons, which may be scattered into the loss cone. On their subsequent bounce, these electrons will precipitate in the upper atmosphere, causing new ionization and optical emissions. The resulting ionization increase has been measured for decades as lightning-induced electron precipitation (LEP) events, but the optical signature has never been studied. We present model calculations to predict the intensity of these optical emissions in a number of bands and lines, including the 5577 Å and 6300 Å lines of Oxygen, and the N2 1P and N2+ 1N band systems of Nitrogen. This modeling effort involves a four-step procedure: first, the lightning impulse is ray-traced through the ionosphere and magnetosphere, and calculations of the wave-particle interaction in the equatorial region result in estimates of the precipitated flux of electrons. Next, a Monte Carlo simulation of this flux is used to determine altitude profiles of deposited energy. Third, this deposited energy is converted to altitude profiles of ionization and optical emissions; and finally, line-of-sight integration to ground- or space-based observers yields estimates of observable brightness. We find that the predicted emissions may reach as high as ~50 R in the green 5577 Å line for a 100 kA cloud-to-ground discharge, and should be observable with photometric instruments. We compare these results to those of VLF transmitter-induced precipitation, which is orders of magnitude weaker, but has the advantage of being a controllable experiment. We further investigate the effect of latitude, lightning peak current, and radiation belt and

  13. Precipitation processes as deduced by combining Doppler radar and disdrometer

    Science.gov (United States)

    Thomson, Alan Douglas

    Precipitation processes are investigated in stratiform and convective weather systems by combining Doppler radar and disdrometer measurements. Vertical scans are designed to measure the standard radar data fields and the power spectrum of the vertical Doppler velocities with high spatial and temporal resolution. A new method, based on iterative application of a disdrometer-determined Z-R relation, is developed to estimate vertical winds from the vertical scan data. Using this method, radar-based raindrop size spectra calculated near the surface in light stratiform rain compare well with simultaneous measurements from a collocated disdrometer. A full raindrop size spectrum profile is deduced for a specific steady state case. It is found that the spectrum does not vary with height, suggesting that the spectral shape is mainly controlled by the ice particles occurring above the 0oC level. Vertical scan data are also combined with volume scan data obtained by the Atmospheric Environment Service King City radar to examine the precipitation structure of a hail producing region within a severe squall line. The vertical scan shows a large variation in precipitation structure and also reveals important storm features which, in this case, are not detected by the conventional volume scans, such as a weak echo vault, a downdraught outflow, and streaks of very high downward velocity corresponding to separate hail trajectories. The power spectra were used to identify and locate hailstones, to deduce the growth of descending hailstones, and to qualitatively examine properties of raindrop size spectra. A conceptual model of hail formation is proposed by comparing the deduced storm structure and precipitation processes with the analyses of two somewhat similar storms documented in the literature.

  14. Research on the dry intrusion accompanying the low vortex precipitation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    By employing the 6.7μm satellite vapor cloud images and NCEP/NCAR 1°×1° reanalysis datasets, the characteristics and mechanism of the dry intrusion, as well as its impacts on the low vortex precipitation at the Meiyu front are explored in this paper. It is found that the formation,development and maintenance of the low vortex precipitation at the Meiyu front are closely related to the evolution of the dry intrusion. The dry intrusion is characterized by high potential vorticity (PV), low humidity and cold air. The dry intrusion exhibits as an obvious dark zone on vapor cloud images, an area in which atmospheric relative humidity is lower than 60%. However, the features of the dry intrusion on the vapor images are clearer than that of the humidity field, for the former is the digital vapor cloud images with high temporal and spatial resolution, and it can be used to explore the finer characteristics of the development, evolution and supplement of the intrusion during the development of the low vortex. The dry intrusion impacts accompanying the low vortex precipitation at the Meiyu front come from all levels of the troposphere, with the strongest intrusion located at the upper troposphere. The dry and cold air intrudes the vicinity of the low vortex from the upper isentropic surface to the lower one, slanting east-ward from lower to higher level. The low vortex precipitation region is usually situated in front of the dry intrusion where the relative humidity gradient is higher. The research also reveals that the mechanism of the dry intrusion is that the high potential vorticity descends from the upper troposphere to the lower level, therefore, the dry intrusion can be used as an important index of the high PV forcing. To the west of the low vortex precipitation, the upper level northerlies descend across the isentropic surface, then the dry cold advection can trigger the instable development in the midlow troposphere. The dry intru-sion enhances the low vortex

  15. The North Atlantic Oscillation and oceanic precipitation variability

    Energy Technology Data Exchange (ETDEWEB)

    Mariotti, Annarita [University of Maryland, Earth System Science Interdisciplinary Center (ESSIC), College Park, MD (United States); ENEA, Rome (Italy); Arkin, Phillip [University of Maryland, Earth System Science Interdisciplinary Center (ESSIC), College Park, MD (United States)

    2007-01-15

    Global North Atlantic Oscillation (NAO) oceanic precipitation features in the latter half of the twentieth century are documented based on the intercomparison of multiple state-of-the-art precipitation datasets and the analysis of the NAO atmospheric circulation and SST anomalies. Most prominent precipitation anomalies occur over the ocean in the North Atlantic, where in winter a ''quadrupole-like'' pattern is found with centers in the western tropical Atlantic, sub-tropical Atlantic, high-latitude eastern Atlantic and over the Labrador Sea. The extent of the sub-tropical and high-latitude center and the amount of explained variance (over 50%) are quite remarkable. However, the tropical Atlantic center is probably the most intriguing feature of this pattern apparently linking the NAO with ITCZ variability. In summer, the pattern is ''tripole-like'' with centers in the eastern Mediterranean Sea, the North Sea/Baltic Sea and in the sub-polar Atlantic. In the eastern Indian Ocean, the correlation is positive in winter and negative in summer, with some link to ENSO variability. The sensitivity of these patterns to the choice of the NAO index is minor in winter while quite important in summer. Interannual NAO precipitation anomalies have driven similar fresh water variations in these ''key'' regions. In the sub-tropical and high-latitude Atlantic in winter precipitation anomalies have been roughly 15 and 10% of climatology per unit change of the NAO, respectively. Decadal changes of the NAO during the last 50 years have also influenced precipitation and fresh water flux at these time-scales, with values lower (higher) than usual in the high-latitude eastern North Atlantic (Labrador Sea) in the 1960s and the late 1970s, and an opposite situation since the early 1980s; in summer the North Sea/Baltic region has been drier than usual during the period 1965-1975 when the NAO was generally positive. (orig.)

  16. Temporal variability in a stochastic precipitation field simulator

    Science.gov (United States)

    Kolberg, Sjur

    2016-04-01

    The space-time statistics of short-term precipitation is studied for two cities in northern Europe, and related to radiosonde observations. The motivation is to construct the temporally varying parameters needed to drive a stochastic short-term precipitation generator. Moments, intermittency, semivariograms, temporal covariance and advection parameters need to be characterised in order to produce realistic scenario simulations for extreme value estimation at different scales. It is hoped that the temporal variability in these parameters can be related to radiosonde data. Hourly values from 46 precipitation stations within a 100*130 km2 region around Copenhagen during the period 1979-2012 is analysed. Bi-daily radiosonde profiles are present from 1969 to 2006. These soundings (vertical profiles of temperature, dew point and wind vector) describe the atmospheric moisture content and convective potential of the current weather situation. Preliminary analysis show that some of the indices extracted from the 12h radiosonde data show good temporal autocorrelation, supporting interpolation to match the 1-hour precipitation data. The precipitation data show a rapidly decreasing temporal autocorrelation function (typically below 0.5 above approx. 12 km), indicating that there is a high variance fraction below scales that the station network is able to reveal. The second data set consists of 7.5-minute C-band radar data from Trondheim, available from June 2013 to October 2015. During the 2014 and 2015 summer seasons, around 25 tipping-bucket precipitation gauges within a 15*20 km area supply observations with temporal resolution down to minute-scale. Nearby radiosonde data are available bi-daily from 1963 to 2015. These data will be explored to provide insight in high-frequency spatial and temporal variability not detectable from the long-term Copenhagen data set. The analysis is a part of the EU-7FP project "Pearl" (http://www.pearl-fp7.eu/, Greve case study), the Norwegian

  17. Clear sky atmosphere at cm-wavelengths from climatology data

    OpenAIRE

    Lew, Bartosz; Uscka-Kowalkowska, Joanna

    2015-01-01

    We utilise ground-based, balloon-borne and satellite climatology data to reconstruct site and season-dependent vertical profiles of precipitable water vapour (PWV). We use these profiles to solve radiative transfer through the atmosphere, and derive atmospheric brightness temperature ($T_{\\rm atm}$) and optical depth ($\\tau$) at centimetre wavelengths. We validate the reconstruction by comparing the model column PWV with photometric measurements of PWV, performed in clear sky conditions point...

  18. Influence of sea ice cover on high latitude precipitation: Inferences from precipitation isotope measurements and a 2D model

    Science.gov (United States)

    Posmentier, E. S.; Faiia, A.; Feng, X.; Michel, F. A.

    2009-12-01

    The most widely cited climate feedback in the Arctic region is ice cover. Warming climate reduces the sea ice extent, which causes a lower surface albedo, resulting in more absorbed insolation and further warming - a positive feedback. Conversely, warming is also likely to result in increased Arctic evaporation and precipitation, leading to increased snow cover and a higher Arctic terrestrial albedo, which would cause cooling - a negative feedback. The balance between these feedbacks must be understood and quantified in order to predict climate response to influences such as increased greenhouse gases. Here, we use measurements of high latitude precipitation isotopes and a 2D model to investigate interannual variability in the contributions of subtropical and Arctic vapor sources to Arctic precipitation. In a previous study, we used isotopic ratios alone to investigate the sources of moisture to the Arctic. We found significant positive relationships between ice area and the d-excess of precipitation on both interannual and seasonal timescales, an expected result under the assumption that sea ice prevents evaporation from the sea surface and consequently reduces the contribution of Arctic moisture with low d-excess values to Arctic precipitation. In this work, we go a step further with an attempt to estimate the influence of sea ice cover on Arctic evaporation using a 2D model and constraining it with high latitude isotopic measurements. The 2D model is a vertical-meridional mass conservation model for H2O, HDO, and H218O with prescribed atmospheric circulation and temperatures. For each isotope, the rates of surface evaporation, sublimation, precipitation, and reevaporation of falling hydrometeors are calculated, and values of the humidity and isotopic concentrations of both vapor and hydrometeors are computed interdependently with the four process rates.. The model fractionation associated with the four processes is based primarily on the work of Jouzel and

  19. Predictability of horizontal water vapor transport relative to precipitation: Enhancing situational awareness for forecasting western U.S. extreme precipitation and flooding

    Science.gov (United States)

    Lavers, David A.; Waliser, Duane E.; Ralph, F. Martin; Dettinger, Michael D.

    2016-03-01

    The western United States is vulnerable to socioeconomic disruption due to extreme winter precipitation and floods. Traditionally, forecasts of precipitation and river discharge provide the basis for preparations. Herein we show that earlier event awareness may be possible through use of horizontal water vapor transport (integrated vapor transport (IVT)) forecasts. Applying the potential predictability concept to the National Centers for Environmental Prediction global ensemble reforecasts, across 31 winters, IVT is found to be more predictable than precipitation. IVT ensemble forecasts with the smallest spreads (least forecast uncertainty) are associated with initiation states with anomalously high geopotential heights south of Alaska, a setup conducive for anticyclonic conditions and weak IVT into the western United States. IVT ensemble forecasts with the greatest spreads (most forecast uncertainty) have initiation states with anomalously low geopotential heights south of Alaska and correspond to atmospheric rivers. The greater IVT predictability could provide warnings of impending storminess with additional lead times for hydrometeorological applications.

  20. Predictability of horizontal water vapor transport relative to precipitation: Enhancing situational awareness for forecasting western U.S. extreme precipitation and flooding

    Science.gov (United States)

    Lavers, David A.; Waliser, Duane E.; Ralph, F. Martin; Dettinger, Michael

    2016-01-01

    The western United States is vulnerable to socioeconomic disruption due to extreme winter precipitation and floods. Traditionally, forecasts of precipitation and river discharge provide the basis for preparations. Herein we show that earlier event awareness may be possible through use of horizontal water vapor transport (integrated vapor transport (IVT)) forecasts. Applying the potential predictability concept to the National Centers for Environmental Prediction global ensemble reforecasts, across 31 winters, IVT is found to be more predictable than precipitation. IVT ensemble forecasts with the smallest spreads (least forecast uncertainty) are associated with initiation states with anomalously high geopotential heights south of Alaska, a setup conducive for anticyclonic conditions and weak IVT into the western United States. IVT ensemble forecasts with the greatest spreads (most forecast uncertainty) have initiation states with anomalously low geopotential heights south of Alaska and correspond to atmospheric rivers. The greater IVT predictability could provide warnings of impending storminess with additional lead times for hydrometeorological applications.