On the influence of simulated SST warming on rainfall projections in the Indo-Pacific domain: an AGCM study

Science.gov (United States)

Zhang, Huqiang; Zhao, Y.; Moise, A.; Ye, H.; Colman, R.; Roff, G.; Zhao, M.

2018-02-01

Significant uncertainty exists in regional climate change projections, particularly for rainfall and other hydro-climate variables. In this study, we conduct a series of Atmospheric General Circulation Model (AGCM) experiments with different future sea surface temperature (SST) warming simulated by a range of coupled climate models. They allow us to assess the extent to which uncertainty from current coupled climate model rainfall projections can be attributed to their simulated SST warming. Nine CMIP5 model-simulated global SST warming anomalies have been super-imposed onto the current SSTs simulated by the Australian climate model ACCESS1.3. The ACCESS1.3 SST-forced experiments closely reproduce rainfall means and interannual variations as in its own fully coupled experiments. Although different global SST warming intensities explain well the inter-model difference in global mean precipitation changes, at regional scales the SST influence vary significantly. SST warming explains about 20-25% of the patterns of precipitation changes in each of the four/five models in its rainfall projections over the oceans in the Indo-Pacific domain, but there are also a couple of models in which different SST warming explains little of their precipitation pattern changes. The influence is weaker again for rainfall changes over land. Roughly similar levels of contribution can be attributed to different atmospheric responses to SST warming in these models. The weak SST influence in our study could be due to the experimental setup applied: superimposing different SST warming anomalies onto the same SSTs simulated for current climate by ACCESS1.3 rather than directly using model-simulated past and future SSTs. Similar modelling and analysis from other modelling groups with more carefully designed experiments are needed to tease out uncertainties caused by different SST warming patterns, different SST mean biases and different model physical/dynamical responses to the same underlying

SST and OLR relationship during Indian summer monsoon: a coupled climate modelling perspective

Science.gov (United States)

Chaudhari, Hemantkumar S.; Hazra, Anupam; Pokhrel, Samir; Chakrabarty, Chandrima; Saha, Subodh Kumar; Sreenivas, P.

2018-04-01

The study mainly investigates sea surface temperature (SST) and outgoing longwave radiation (OLR) relationships in coupled climate model. To support the analysis, high-level cloud and OLR relationship is also investigated. High-level cloud and OLR relationship depicts significant negative correlation over the entire monsoon regime. Coupled climate model is able to produce the same. SST and OLR relationship in observation also depicts significant negative relationship, in particular, over the Equatorial Eastern Indian Ocean (EIO) region. Climate Forecast System version 2 (CFSv2) is able to portray the negative relationship over EIO region; however, it is underestimated as compared to observation. Significant negative correlations elucidate that local SSTs regulate the convection and further it initiates Bjerknes feedback in the central Indian Ocean. It connotes that SST anomalies during monsoon period tend to be determined by oceanic forcing. The heat content of the coastal Bay of Bengal shows highest response to EIO SST by a lag of 1 month. It suggests that the coastal region of the Bay of Bengal is marked by coastally trapped Kelvin waves, which might have come from EIO at a time lag of 1 month. Sea surface height anomalies, depth at 20 °C isotherms and depth at 26 isotherms also supports the above hypothesis. Composite analysis based on EIO index and coupled climate model sensitivity experiments also suggest that the coastal Bay of Bengal region is marked by coastally trapped Kelvin waves, which are propagated from EIO at a time lag of 1 month. Thus, SST and OLR relationship pinpoints that the Bay of Bengal OLR (convection) is governed by local ocean-atmospheric coupling, which is influenced by the delayed response from EIO brought forward through oceanic planetary waves at a lag of 1 month. These results have utmost predictive value for seasonal and extended range forecasting. Thus, OLR and SST relationship can constitute a pivotal role in investigating the

Tropical impacts of SST forcing: A case study for 1987 versus 1988

Science.gov (United States)

Druyan, Leonard M.; Hastenrath, Stefan

1994-01-01

The response of the NASA/Goddard Institute for Space Studies general circulation model (GCM) to large tropical sea surface temperature (SST) anomalies is investigated by evaluating model simulations of the particularly contrasting summer monsoon seasons 1987 and 1988. These years are representative of the warm and cold phases, respectively, of a recent El Nino-Southern Oscillation (ENSO) event. An ensemble averaging the results of three simulations was considered for each season, using monthly mean observed SST anomalies for June-August 1987 and 1988 as lower boundary forcing. Consistent with the European Center for Medium Weather Forecast (ECMWF)-analyzed winds, the simulations based on 1988 as compared to 1987 SST exhibit stronger upper-tropospheric irrotational circulation between the monsoon regions and the Southern Hemispheric sub-tropical anticyclones, a stronger Pacific Walker cell and a weaker subtropical westerly jet over the South Pacific. In the same vein, the modeled precipitation, indicating a more northerly position of the Pacific Inter-Tropical Convergence Zone (ITCZ) in 1988 compared with 1987, is supported by satellite observations of outgoing longwave radiation and highly reflective clouds.

OceanXtremes: Scalable Anomaly Detection in Oceanographic Time-Series

Science.gov (United States)

Wilson, B. D.; Armstrong, E. M.; Chin, T. M.; Gill, K. M.; Greguska, F. R., III; Huang, T.; Jacob, J. C.; Quach, N.

2016-12-01

The oceanographic community must meet the challenge to rapidly identify features and anomalies in complex and voluminous observations to further science and improve decision support. Given this data-intensive reality, we are developing an anomaly detection system, called OceanXtremes, powered by an intelligent, elastic Cloud-based analytic service backend that enables execution of domain-specific, multi-scale anomaly and feature detection algorithms across the entire archive of 15 to 30-year ocean science datasets.Our parallel analytics engine is extending the NEXUS system and exploits multiple open-source technologies: Apache Cassandra as a distributed spatial "tile" cache, Apache Spark for in-memory parallel computation, and Apache Solr for spatial search and storing pre-computed tile statistics and other metadata. OceanXtremes provides these key capabilities: Parallel generation (Spark on a compute cluster) of 15 to 30-year Ocean Climatologies (e.g. sea surface temperature or SST) in hours or overnight, using simple pixel averages or customizable Gaussian-weighted "smoothing" over latitude, longitude, and time; Parallel pre-computation, tiling, and caching of anomaly fields (daily variables minus a chosen climatology) with pre-computed tile statistics; Parallel detection (over the time-series of tiles) of anomalies or phenomena by regional area-averages exceeding a specified threshold (e.g. high SST in El Nino or SST "blob" regions), or more complex, custom data mining algorithms; Shared discovery and exploration of ocean phenomena and anomalies (facet search using Solr), along with unexpected correlations between key measured variables; Scalable execution for all capabilities on a hybrid Cloud, using our on-premise OpenStack Cloud cluster or at Amazon. The key idea is that the parallel data-mining operations will be run "near" the ocean data archives (a local "network" hop) so that we can efficiently access the thousands of files making up a three decade time

ESA STSE “SST Diurnal Variability: Regional Extend - Implications in Atmospheric Modelling”

DEFF Research Database (Denmark)

Karagali, Ioanna

The diurnal variability of SST, driven by the coincident occurrence of low enough wind and solar heating, has been observed in various regions of the global ocean [4, 5, 6]. Atmospheric, oceanic and climate models are not adequately resolving the daily SST cycle, resulting in biases of the total...

Caribbean Sea rainfall variability during the rainy season and relationship to the equatorial Pacific and tropical Atlantic SST

Energy Technology Data Exchange (ETDEWEB)

Wu, Renguang [Institute of Global Environment and Society, Center for Ocean-Land-Atmosphere Studies, Calverton, MD (United States); Kirtman, Ben P. [University of Miami, Rosenstiel School of Marine and Atmospheric Sciences, Miami, FL (United States)

2011-10-15

The present study investigates the Caribbean Sea rainfall variability during the early and late rainy seasons and its association with sea surface temperature (SST) and air-sea interaction based on observational estimates, the NCEP Climate Forecast System (CFS) and Global Forecast System (GFS) simulations, and the CFS retrospective forecasts. Analysis of the observational estimates indicates that air-sea interaction is important over the Caribbean Sea, whereas the atmospheric forcing of SST dominates over the Gulf of Mexico. The CFS simulation captures the basic elements of this observed air-sea relationship. The GFS simulation produces spurious SST forcing of the atmosphere over the Gulf of Mexico largely due to prescribing SST. The CFS forecasts capture the air-sea relationship in the late rainy season (August-October), but cannot reproduce the SST forcing of atmosphere over the Caribbean Sea in the early rainy season (May-July). An empirical orthogonal function (EOF) analysis indicates that the leading modes of percent anomalies of the rainy season precipitation have the largest loading in the southern Caribbean Sea in observations. The model simulations and forecasts skillfully reproduce the spatial pattern, but not the temporal evolution. The Caribbean Sea rainfall variability in the early rainy season is mainly due to the tropical North Atlantic (TNA) SST anomalies in observations, is contributed by both the TNA and eastern equatorial Pacific (EEP) SST anomalies in the CFS simulation, and has an overly large impact from the EEP SST anomalies in the GFS simulation and the CFS forecasts. The observed Caribbean Sea rainfall variability in the late rainy season has a leading impact from the EEP SST anomalies, with a secondary contribution from the TNA SST anomalies. In comparison, the model simulations and forecasts overestimate the impacts of the EEP SST anomalies due to an earlier development and longer duration of the El Nino-Southern Oscillation in the CFS

South Asian Summer Monsoon Rainfall Variability and Trend: Its Links to Indo-Pacific SST Anomalies and Moist Processes

Science.gov (United States)

Prasanna, V.

2016-06-01

The warm (cold) phase of El Niño (La Niña) and its impact on all Indian Summer Monsoon rainfall (AISMR) relationship is explored for the past 100 years. The 103-year (1901-2003) data from the twentieth century reanalysis datasets (20CR) and other major reanalysis datasets for southwest monsoon season (JJAS) is utilized to find out the simultaneous influence of the El Niño Southern Oscillation (ENSO)-AISMR relationship. Two cases such as wet, dry monsoon years associated with ENSO(+) (El Niño), ENSO(-) (La Niña) and Non-ENSO (neutral) events have been discussed in detail using observed rainfall and three-dimensional 20CR dataset. The dry and wet years associated with ENSO and Non-ENSO periods show significant differences in the spatial pattern of rainfall associated with three-dimensional atmospheric composite, the 20CR dataset has captured the anomalies quite well. During wet (dry) years, the rainfall is high (low), i.e. 10 % above (below) average from the long-term mean and this wet or dry condition occur both during ENSO and Non-ENSO phases. The Non-ENSO year dry or wet composites are also focused in detail to understand, where do the anomalous winds come from unlike in the ENSO case. The moisture transport is coherent with the changes in the spatial pattern of AISMR and large-scale feature in the 20CR dataset. Recent 50-year trend (1951-2000) is also analyzed from various available observational and reanalysis datasets to see the influence of Indo-Pacific SST and moist processes on the South Asian summer monsoon rainfall trend. Apart from the Indo-Pacific sea surface temperatures (SST), the moisture convergence and moisture transport among India (IND), Equatorial Indian Ocean (IOC) and tropical western pacific (WNP) is also important in modifying the wet or dry cycles over India. The mutual interaction among IOC, WNP and IND in seasonal timescales is significant in modifying wet and dry cycles over the Indian region and the seasonal anomalies.

Analysis of Pathfinder SST algorithm for global and regional conditions

Indian Academy of Sciences (India)

SST algorithms to improve the present accuracy of surface temperature measurements ... regions, except in the North Atlantic and adjacent seas, where the residuals are always positive. ..... the stratosphere causing significant contamination of.

Spring Soil Temperature Anomalies over Tibetan Plateau and Summer Droughts/Floods in East Asia

Science.gov (United States)

Xue, Y.; Li, W.; LI, Q.; Diallo, I.; Chu, P. C.; Guo, W.; Fu, C.

2017-12-01

Recurrent extreme climate events, such as droughts and floods, are important features of the climate of East Asia, especially over the Yangtze River basin. Many studies have attributed these episodes to variability and anomaly of global sea surface temperatures (SST) anomaly. In addition, snow in the Tibetan Plateau has also been considered as one of the factors affecting the Asian monsoon variability. However, studies have consistently shown that SST along is unable to explain the extreme climate events fully and snow has difficulty to use as a predictor. Remote effects of observed large-scale land surface temperature (LST) and subsurface temperature variability in Tibetan Plateau (TP) on East Asian regional droughts/floods, however, have been largely ignored. We conjecture that a temporally filtered response to snow anomalies may be preserved in the LST anomaly. In this study, evidence from climate observations and model simulations addresses the LST/SUBT effects. The Maximum Covariance Analysis (MCA) of observational data identifies that a pronounce spring LST anomaly pattern over TP is closely associated with precipitation anomalies in East Asia with a dipole pattern, i.e., negative/positive TP spring LST anomaly is associated with the summer drought/flood over the region south of the Yangtze River and wet/dry conditions to the north of the Yangtze River. Climate models were used to demonstrate a causal relationship between spring cold LST anomaly in the TP and the severe 2003 drought over the southern part of the Yangtze River in eastern Asia. This severe drought resulted in 100 x 106 kg crop yield losses and an economic loss of 5.8 billion Chinese Yuan. The modeling study suggests that the LST effect produced about 58% of observed precipitation deficit; while the SST effect produced about 32% of the drought conditions. Meanwhile, the LST and SST effects also simulated the observed flood over to the north of the Yangtze River. This suggests that inclusion of

The relationship between sea surface temperature anomalies and atmospheric circulation in general circulation model experiments

International Nuclear Information System (INIS)

Kharin, V.V.

1994-01-01

Several multi-year integrations of the Hamburg version of the ECMWF/T21 general circulation model driven by the sea surface temperature (SST) observed in the period 1970-1988 were examined to study the extratropical response of the atmospheric circulation to SST anomalies in the Northern Hemisphere in winter. In the first 19-years run SST anomalies were prescribed globally (GAGO run), and in two others SST variability was limited to extratropical regions (MOGA run) and to tropics (TOGA run), respectively. A canonical correlation analysis was applied to the monthly means to find the best correlated patterns of SST anomalies in the Atlantic and Pacific Oceans and the Northern Hemisphere atmospheric flow. Contrary to expectation, the extratropical response in the GAGO run is not equal to the linear combination of the responses in the MOGA and TOGA runs. In the GAGO integration with globally prescribed SST the best correlated atmospheric pattern is global and is characterized by dipole structures of the same polarity in the North Atlantic and the North Pacific sectors. In the MOGA and TOGA experiments the atmospheric response is more local with main centers in the North Atlantic and North Pacific, respectively. The atmospheric modes found by the CCA were compared with the normal modes of the barotropic vorticity equation linearized about the 500 mb winter climate of the control integration driven by the climatological SST. The normal modes with smallest eigenvalues are similar to the canonical patterns of 500 mb geopotential height. The corresponding eigenvectors of the adjoint operator, which represent an external forcing optimal for exciting normal modes, have a longitudinal structure with maxima in regions characterized by enhanced high frequency baroclinic activity over both oceans. It was suggested that variability of storm tracks could play an important role in variability of the barotropic normal modes. (orig.)

The effects of sea surface temperature anomalies on oceanic coral reef systems in the southwestern tropical Atlantic

Science.gov (United States)

Ferreira, B. P.; Costa, M. B. S. F.; Coxey, M. S.; Gaspar, A. L. B.; Veleda, D.; Araujo, M.

2013-06-01

In 2010, high sea surface temperatures that were recorded in several parts of the world and caused coral bleaching and coral mortality were also recorded in the southwest Atlantic Ocean, between latitudes 0°S and 8°S. This paper reports on coral bleaching and diseases in Rocas Atoll and Fernando de Noronha archipelago and examines their relationship with sea surface temperature (SST) anomalies recorded by PIRATA buoys located at 8°S30°W, 0°S35°W, and 0°S23°W. Adjusted satellite data were used to derive SST climatological means at buoy sites and to derive anomalies at reef sites. The whole region was affected by the elevated temperature anomaly that persisted through 2010, reaching 1.67 °C above average at reef sites and 1.83 °C above average at buoys sites. A significant positive relationship was found between the percentage of coral bleaching that was observed on reef formations and the corresponding HotSpot SST anomaly recorded by both satellite and buoys. These results indicate that the warming observed in the ocean waters was followed by a warming at the reefs. The percentage of bleached corals persisting after the subsidence of the thermal stress, and disease prevalence increased through 2010, after two periods of thermal stress. The in situ temperature anomaly observed during the 2009-2010 El Niño event was equivalent to the anomaly observed during the 1997-1998 El Niño event, explaining similar bleaching intensity. Continued monitoring efforts are necessary to further assess the relationship between bleaching severity and PIRATA SST anomalies and improve the use of this new dataset in future regional bleaching predictions.

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

Interannual to Decadal SST Variability in the Tropical Indian Ocean

Science.gov (United States)

Wang, G.; Newman, M.; Han, W.

2017-12-01

The Indian Ocean has received increasing attention in recent years for its large impacts on regional and global climate. However, due mainly to the close interdependence of the climate variation within the Tropical Pacific and the Indian Ocean, the internal sea surface temperature (SST) variability within the Indian Ocean has not been studied extensively on longer time scales. In this presentation we will show analysis of the interannual to decadal SST variability in the Tropical Indian Ocean in observations and Linear Inverse Model (LIM) results. We also compare the decoupled Indian Ocean SST variability from the Pacific against fully coupled one based on LIM integrations, to test the factors influence the features of the leading SST modes in the Indian Ocean. The result shows the Indian Ocean Basin (IOB) mode, which is strongly related to global averaged SST variability, passively responses to the Pacific variation. Without tropical Indo-Pacific coupling interaction, the intensity of IOB significantly decreases by 80%. The Indian Ocean Dipole (IOD) mode demonstrates its independence from the Pacific SST variability since the IOD does not change its long-term characteristics at all without inter-basin interactions. The overall SSTA variance decreases significantly in the Tropical Indian Ocean in the coupling restricted LIM runs, especially when the one-way impact from the Pacific to the Indian Ocean is turned off, suggesting that most of the variability in the Indian Ocean comes from the Pacific influence. On the other hand, the Indian Ocean could also transport anomalies to the Pacific, making the interaction a complete two-way process.

Mechanisms of northeastern Brazil rainfall anomalies due to Southern Tropical Atlantic variability

Science.gov (United States)

Neelin, J.; Su, H.

2004-05-01

Observational studies have shown that the rainfall anomalies in eastern equatorial South America, including Nordeste Brazil, have a positive correlation with tropical southern Atlantic sea surface temperature (SST) anomalies. Such relationships are reproduced in model simulations with the quasi-equilibrium tropical circulation model (QTCM), which includes a simple land model. A suite of model ensemble experiments is analysed using observed SST over the tropical oceans, the tropical Atlantic and the tropical southern Atlantic (30S-0), respectively (with climatological SST in the remainder of the oceans). Warm tropical south Atlantic SST anomalies yield positive precipitation anomalies over the Nordeste and the southern edge of the Atlantic marine intertropical convergence zone (ITCZ). Mechanisms associated with moisture variations are responsible for the land precipitation changes. Increases in moisture over the Atlantic cause positive anomalies in moisture advection, spreading increased moisture downwind. Where the basic state is far from the convective stability threshold, moisture changes have little effect, but the margins of the climatological convection zone are affected. The increased moisture supply due to advection is enhanced by increases in low-level convergence required by moist static energy balances. The moisture convergence term is several times larger, but experiments altering the moisture advection confirm that the feedback is initiated by wind acting on moisture gradient. This mechanism has several features in common with the recently published "upped-ante" mechanism for El Nino impacts on this region. In that case, the moisture gradient is initiated by warm free tropospheric temperature anomalies increasing the typical value of low-level moisture required to sustain convection in the convection zones. Both mechanisms suggest the usefulness of coordinating ocean and land in situ observations of boundary layer moisture.

Climatic anomaly affects the immune competence of California sea lions.

Directory of Open Access Journals (Sweden)

Marina Banuet-Martínez

Full Text Available The past decades have been characterized by a growing number of climatic anomalies. As these anomalies tend to occur suddenly and unexpectedly, it is often difficult to procure empirical evidence of their effects on natural populations. We analysed how the recent sea surface temperature (SST anomaly in the northeastern Pacific Ocean affects body condition, nutritional status, and immune competence of California sea lion pups. We found that pup body condition and blood glucose levels of the pups were lower during high SST events, although other biomarkers of malnutrition remained unchanged, suggesting that pups were experiencing early stages of starvation. Glucose-dependent immune responses were affected by the SST anomaly; specifically, pups born during high SST events had lower serum concentrations of IgG and IgA, and were unable to respond to an immune challenge. This means that not only were pups that were born during the SST anomaly less able to synthesize protective antibodies; they were also limited in their ability to respond rapidly to nonspecific immune challenges. Our study provides empirical evidence that atypical climatic conditions can limit energetic reserves and compromise physiological responses that are essential for the survival of a marine top predator.

Evaporation/SST Sensitivity Over the Tropical Oceans During ENSO Events as Estimated from the da Silva, Young, Levitus Surface Marine Data Set

Science.gov (United States)

Robertson, F. R.; Fitzjarrald, D. E.; Sohn, B.-J.; Arnold, James E. (Technical Monitor)

2001-01-01

The da Silva, Young and Levitus Surface Marine Atlas, based on observations from the Comprehensive Ocean Atmosphere Data Set (COADS) Release 1, has been used to investigate the relationship between evaporation and sea-surface temperature (SST) over the global oceans. For the period 1950 to 1987 SST, surface latent heat flux, and other related variables have been filtered to minimize data uncertainties and to focus upon interannual variations associated with warm (El Nino) and cold (La Nina) ENSO events. Compositing procedures have enabled identification of systematic variations in latent heat fluxes accompanying these events and the relationship to spatial anomalies in ocean surface wind speed and humidity. The evaporation response associated with ENSO sea surface temperature (SST) variability is systematic in nature and composed of offsetting contributions from the surface wind and humidity variations. During warm events exceeding 1.0 S.D. delta SST, increases in the surface humidity deficit, delta(qs-qa), between the surface and 2m height dominate regions of positive SST anomalies and lead to increases in evaporation of almost 2 Wm (exp -2) at deltaSST = 0.23 K. Despite the increases in specific humidity, relative humidity decreases slightly in regions of elevated SSTs. For the most part, variations in wind speed are consistent with previous investigations. Weakening of the equatorial easterlies (and generation of westerlies) between 160 degrees E and 140 degrees W dominates during the early phases of warm events. Elevated wind speeds in adjacent subtropical regions and in the eastern equatorial Pacific subsequently develop too. The net contribution of these winds, which reflect adjustments in Hadley and Walker circulation components is toward reduced evaporation. Results for cold periods are approximately similar, but opposite in sign to warm events, though evidence of different temporal evolution is noted.

The relative importance of ENSO and tropical Atlantic sea surface temperature anomalies for seasonal precipitation over South America: a numerical study

Science.gov (United States)

Pezzi, L. P.; Cavalcanti, I. F. A.

The role of tropical Atlantic sea surface temperature (SST) anomalies during ENSO episodes over northeast Brazil (Nordeste) is investigated using the CPTEC/COLA Atmospheric General Circulation Model (AGCM). Four sets of integrations are performed using SST in El Niño and La Niña (ENSO) episodes, changing the SST of the Atlantic Ocean. A positive dipole (SST higher than normal in the tropical North Atlantic and below normal in the tropical South Atlantic) and a negative dipole (opposite conditions), are set as the boundary conditions of SST in the Atlantic Ocean. The four experiments are performed using El Niño or La Niña SST in all oceans, except in the tropical Atlantic where the two phases of the SST dipole are applied. Five initial conditions were integrated in each case in order to obtain four ensemble results. The positive SST dipole over the tropical Atlantic Ocean and El Niño conditions over the Pacific Ocean resulted in dry conditions over the Nordeste. When the negative dipole and El Niño conditions over the Pacific Ocean were applied, the results showed precipitation above normal over the north of Nordeste. When La Niña conditions over Pacific Ocean were tested together with a negative dipole, positive precipitation anomalies occurred over the whole Nordeste. Using the positive dipole over the tropical Atlantic, the precipitation over Nordeste was below average. During La Niña episodes, the Atlantic Ocean conditions have a larger effect on the precipitation of Nordeste than the Pacific Ocean. In El Niño conditions, only the north region of Nordeste is affected by the Atlantic SST. Other tropical areas of South America show a change only in the intensity of anomalies. Central and southeast regions of South America are affected by the Atlantic conditions only during La Niña conditions, whereas during El Niño these regions are influenced only by conditions in the Pacific Ocean.

U.S. West Coast MODIS Aqua High Resolution SST Climatology Fields (July 2002 - March 2014)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This suite of CHLA and SST climatology and anomaly data products are derived from daily, 0.0125 degree x 0.0125 degree, MODIS Aqua CHLA and SST fields that cover the...

G1SST, 1km blended SST

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A daily, global Sea Surface Temperature (SST) data set is produced at 1-km (also known as ultra-high resolution) by the JPL ROMS (Regional Ocean Modeling System)...

Decadal-scale teleconnection between South Atlantic SST and southeast Australia surface air temperature in austral summer

Science.gov (United States)

Xue, Jiaqing; Li, Jianping; Sun, Cheng; Zhao, Sen; Mao, Jiangyu; Dong, Di; Li, Yanjie; Feng, Juan

2018-04-01

Austral summer (December-February) surface air temperature over southeast Australia (SEA) is found to be remotely influenced by sea surface temperature (SST) in the South Atlantic at decadal time scales. In austral summer, warm SST anomalies in the southwest South Atlantic induce concurrent above-normal surface air temperature over SEA. This decadal-scale teleconnection occurs through the eastward propagating South Atlantic-Australia (SAA) wave train triggered by SST anomalies in the southwest South Atlantic. The excitation of the SAA wave train is verified by forcing experiments based on both linear barotropic and baroclinic models, propagation pathway and spatial scale of the observed SAA wave train are further explained by the Rossby wave ray tracing analysis in non-uniform basic flow. The SAA wave train forced by southwest South Atlantic warming is characterized by an anomalous anticyclone off the eastern coast of the Australia. Temperature diagnostic analyses based on the thermodynamic equation suggest anomalous northerly flows on western flank of this anticyclone can induce low-level warm advection anomaly over SEA, which thus lead to the warming of surface air temperature there. Finally, SST-forced atmospheric general circulation model ensemble experiments also demonstrate that SST forcing in the South Atlantic is associated with the SAA teleconnection wave train in austral summer, this wave train then modulate surface air temperature over SEA on decadal timescales. Hence, observations combined with numerical simulations consistently demonstrate the decadal-scale teleconnection between South Atlantic SST and summertime surface air temperature over SEA.

Moisture dynamics of the northward and eastward propagating boreal summer intraseasonal oscillations: possible role of tropical Indo-west Pacific SST and circulation

Science.gov (United States)

Pillai, Prasanth A.; Sahai, A. K.

2016-08-01

Boreal summer intraseasonal oscillation (BSISO) has complex spatial structure due to the co-existence of equatorial eastward and off-equatorial northward propagation in the equatorial Indian Ocean. As a result, equatorial Indian Ocean convection has simultaneous northward and eastward (NE), northward only (N-only) and eastward only (E-only) propagations. It is well established that the convection propagates in the direction of increasing moist static energy (MSE). The moisture and MSE budget analysis reveals that the horizontal advection of anomalous MSE contributes to positive MSE tendency, which is in agreement with the horizontal advection of column integrated moisture anomaly. Northward movement of warm SST and the anomalous moisture advected by zonal wind are the major initiative for the northward propagation of convection from the equatorial Indian Ocean in both NE and N-only category. At the same time warm SST anomaly in the equatorial west Pacific along with moisture advection caused by anomalous meridional wind is important for the equatorial eastward branch of NE propagation. As these anomalies in the west Pacific moves northward, equatorial Indian Ocean convection establishes over the equatorial west Pacific. The absence of these processes confines the BSISO in northward direction for N-only category. In the case of E-only movement, warm SST anomaly and moisture advection by zonal component of wind causes the eastward propagation of convection. Boundary layer moisture convergence always remains east of convection center in E-only propagation, while it coincides with convection centre in other two categories. Thus the present study concludes that the difference in underlying SST and atmospheric circulation in tropical Indo-west Pacific oceanic regions encourage the differential propagation of BSISO convection through moisture dynamics.

Relationship of boreal summer 10-20-day and 30-60-day intraseasonal oscillation intensity over the tropical western North Pacific to tropical Indo-Pacific SST

Science.gov (United States)

Wu, Renguang; Cao, Xi

2017-06-01

The present study contrasts interannual variations in the intensity of boreal summer 10-20-day and 30-60-day intraseasonal oscillations (ISOs) over the tropical western North Pacific and their factors. A pronounced difference is found in the relationship of the two ISOs to El Niño-Southern Oscillation. The 10-20-day ISO intensity is enhanced during El Niño developing summer, whereas the 30-60-day ISO intensity is enhanced during La Niña decaying summer. The above different relationship is interpreted as follows. The equatorial central and eastern Pacific SST anomalies modify vertical wind shear, lower-level moisture, and vertical motion in a southeast-northwest oriented band from the equatorial western Pacific to the tropical western North Pacific where the 10-20-day ISOs originate and propagate. These background field changes modulate the amplitude of 10-20-day ISOs. Preceding equatorial central and eastern Pacific SST anomalies induce SST anomalies in the North Indian Ocean in summer, which in turn modify vertical wind shear and vertical motion over the tropical western North Pacific. The modified background fields influence the amplitude of the 30-60-day ISOs when they reach the tropical western North Pacific from the equatorial region. A feedback of ISO intensity on local SST change is identified in the tropical western North Pacific likely due to a net effect of ISOs on surface heat flux anomalies. This feedback is more prominent from the 10-20-day than the 30-60-day ISO intensity change.

Predictability experiments for the Asian summer monsoon: impact of SST anomalies on interannual and intraseasonal variability

International Nuclear Information System (INIS)

Molteni, Franco; Corti, Susanna; Ferranti, Laura; Slingo, Julia M.

2003-07-01

The effects of SST anomalies on the interannual and intraseasonal variability of the Asian summer monsoon have been studied by multivariate statistical analyses of 850-hPa wind and rainfall fields simulated in a set of ensemble integrations of the ECMWF atmospheric GCM, referred to as the PRISM experiments. The simulations used observed SSTs (PRISM-O), covering 9 years characterised by large variations of the ENSO phenomenon in the 1980's and the early 1990's. A parallel set of simulations was also performed with climatological SSTs (PRISM-C), thus enabling the influence of SST forcing on the modes of interannual and intraseasonal variability to be investigated. As in observations, the model's interannual variability is dominated by a zonally-oriented mode which describes the north-south movement of the tropical convergence zone (TCZ). This mode appears to be independent of SST forcing and its robustness between the PRISM-O and PRISM-C simulations suggests that it is driven by internal atmospheric dynamics. On the other hand, the second mode of variability, which again has a good correspondence with observed patterns, shows a clear relationship with the ENSO cycle. Since the mode related to ENSO accounts for only a small part of the total variance, the notion of a quasi-linear superposition of forced and unforced modes of variability may not provide an appropriate interpretation of monsoon interannual variability. Consequently, the possibility of a non-linear influence has been investigated by exploring the relationship between interannual and intraseasonal variability. As in other studies, a common mode of interannual and intraseasonal variability has been found, in this case describing the north-south transition of the TCZ associated with monsoon active/break cycles. Although seasonal-mean values of the Principal Component (PC) timeseries associated with the leading intraseasonal mode shows no significant correlation with ENSO, the 2-dimensional probability

Predictability experiments for the Asian summer monsoon: Impact of SST anomalies on interannual and intraseasonal variability

International Nuclear Information System (INIS)

Molteni, F.; Corti, S.; Ferranti, L.; Slingo, J.M.

2002-04-01

The effects of SST anomalies on the interannual and intraseasonal variability of the Asian summer monsoon have been studied by multivariate statistical analyses of 850-hPa wind and rainfall yields simulated in a set of ensemble integrations of the ECMWF atmospheric GCM, referred to as the PRISM experiments. The simulations used observed SSTs (PRISM-O), covering 9 years characterised by large variations of the ENSO phenomenon in the 1980's and the early 1990's. A parallel set of simulations was also performed with climatological SSTs (PRISM-C), thus enabling the influence of SST forcing on the modes of interannual and intraseasonal variability to be investigated. As in observations, the model's interannual variability is dominated by a zonally-oriented mode which describes the north-south movement of the tropical convergence zone (TCZ). This mode appears to be independent of SST forcing and its robustness between the PRISM-O and PRISM-C simulations suggests that it is driven by internal atmospheric dynamics. On the other hand, the second mode of variability, which again has a good correspondence with observed patterns, shows a clear relationship with the ENSO cycle. Since the mode related to ENSO accounts for only a small part of the total variance, the notion of a quasi-linear superposition of forced and unforced modes of variability may not provide an appropriate interpretation of monsoon interannual variability. Consequently, the possibility of a non-linear influence has been investigated by exploring the relationship between interannual and intraseasonal variability. As in other studies, a common mode of interannual and intraseasonal variability has been found, in this case describing the north-south transition of the TCZ associated with monsoon active/break cycles. Although seasonal-mean values of the Principal Component (PC) timeseries associated with the leading intraseasonal mode shows no significant correlation with ENSO, the 2-dimensional probability

Role of sea surface temperature anomalies in the tropical Indo-Pacific region in the northeast Asia severe drought in summer 2014: month-to-month perspective

Science.gov (United States)

Xu, Zhiqing; Fan, Ke; Wang, HuiJun

2017-09-01

The severe drought over northeast Asia in summer 2014 and the contribution to it by sea surface temperature (SST) anomalies in the tropical Indo-Pacific region were investigated from the month-to-month perspective. The severe drought was accompanied by weak lower-level summer monsoon flow and featured an obvious northward movement during summer. The mid-latitude Asian summer (MAS) pattern and East Asia/Pacific teleconnection (EAP) pattern, induced by the Indian summer monsoon (ISM) and western North Pacific summer monsoon (WNPSM) rainfall anomalies respectively, were two main bridges between the SST anomalies in the tropical Indo-Pacific region and the severe drought. Warming in the Arabian Sea induced reduced rainfall over northeast India and then triggered a negative MAS pattern favoring the severe drought in June 2014. In July 2014, warming in the tropical western North Pacific led to a strong WNPSM and increased rainfall over the Philippine Sea, triggering a positive EAP pattern. The equatorial eastern Pacific and local warming resulted in increased rainfall over the off-equatorial western Pacific and triggered an EAP-like pattern. The EAP pattern and EAP-like pattern contributed to the severe drought in July 2014. A negative Indian Ocean dipole induced an anomalous meridional circulation, and warming in the equatorial eastern Pacific induced an anomalous zonal circulation, in August 2014. The two anomalous cells led to a weak ISM and WNPSM, triggering the negative MAS and EAP patterns responsible for the severe drought. Two possible reasons for the northward movement of the drought were also proposed.

Regional magnetic anomaly constraints on continental rifting

Science.gov (United States)

Vonfrese, R. R. B.; Hinze, W. J.; Olivier, R.; Bentley, C. R.

1985-01-01

Radially polarized MAGSAT anomalies of North and South America, Europe, Africa, India, Australia and Antarctica demonstrate remarkably detailed correlation of regional magnetic lithospheric sources across rifted margins when plotted on a reconstruction of Pangea. These major magnetic features apparently preserve their integrity until a superimposed metamorphoric event alters the magnitude and pattern of the anomalies. The longevity of continental scale magnetic anomalies contrasts markedly with that of regional gravity anomalies which tend to reflect predominantly isostatic adjustments associated with neo-tectonism. First observed as a result of NASA's magnetic satellite programs, these anomalies provide new and fundamental constraints on the geologic evolution and dynamics of the continents and oceans. Accordingly, satellite magnetic observations provide a further tool for investigating continental drift to compliment other lines of evidence in paleoclimatology, paleontology, paleomagnetism, and studies of the radiometric ages and geometric fit of the continents.

Enhanced Influence of the Tropical Atlantic SST on the Western North Pacific Subtropical High after late 1970s

Science.gov (United States)

Hong, C. C.

2015-12-01

The western North Pacific subtropical high (WNPSH) in boreal summer shows a remarkable enhancement after the late 1970s. Whereas the sea surface temperature (SST) in the North Indian Ocean (NIO) and the equatorial eastern Pacific (EEP) had been noted to have remarkable local or remote effects on enhancing the WNPSH, the influence of the Atlantic SST, so far, is hardly explored. This article reports a new finding: enhanced relationship between the tropical Atlantic (TA)-SST and the WNPSH after the late 1970s. Regression study suggests that the warm TA-SST produced a zonally overturning circulation anomaly, with descending over the central equatorial Pacific and ascending over the tropical Atlantic/eastern Pacific. The anomalous descending over the central equatorial Pacific likely induced low-level anticyclonic anomaly to the west and therefore enhanced the WNPSH. One implication of this new finding is for predictability. The well-known "spring predictability barrier" (i.e., the influence of El Niño and Southern Oscillation (ENSO) falls dramatically during boreal spring) does not apply to the TA-SST/WNPSH relationship. Conversely, the TA-SST shows consistently high correlation starting from boreal spring when the ENSO influence continues declining. The TA-SST pushes the predictability of the WNPSH in boreal summer approximately one season earlier to boreal spring.

Characterisation and quantification of regional diurnal SST cycles from SEVIRI

DEFF Research Database (Denmark)

Karagali, Ioanna; Høyer, J.L.

2014-01-01

seas. Six years of SST fields from SEVIRI are validated against the Advanced Along-Track Scanning Radiometer (AATSR) Reprocessed for Climate (ARC) data set. The overall SEVIRI–AATSR bias is −0.07 K, and the standard deviation is 0.51 K, based on more than 53×106 matchups. Identification of the diurnal...... in the tropics. Longer diurnal warming duration is identified in the high latitudes compared to the tropics. The maximum monthly mean diurnal signal can be up to 0.5K in specific regions....

Leading El-Niño SST Oscillations around the Southern South American Continent

Directory of Open Access Journals (Sweden)

Yu-Chen Hsu

2018-05-01

Full Text Available The inter-annual variations in the sea surface temperatures (SSTs of the tropical and subtropical Pacific Ocean have been widely investigated, largely due to their importance in achieving the sustainable development of marine ecosystems under a changing climate. The El Niño-Southern Oscillation (ENSO is a widely recognized variability. In the subpolar region in the southern hemisphere, the Antarctic Circumpolar Current (ACC is one of the main sources of the Peru Current. A change in the SST in the Southern Ocean may change the physical properties of the seawater in the tropical and subtropical Pacific Ocean. However, the variations in the SST in the Southern Ocean have rarely been addressed. This study uses a 147-year (1870–2016 dataset from the Met Office Hadley Centre to show that the SST anomalies (SSTAs in the oceans west and east of South America and the Antarctic Peninsula have strong positive (R = 0.56 and negative (R = −0.67 correlations with the Niño 3.4 SSTA, respectively. Such correlations are likely related to the changes in circulations of the ACC. We further show that, statistically, the temporal variations in the SSTAs of the ACC lead the Niño 3.4 SSTA by four to six months. Such findings imply that change in the strength of ENSO or circulation under the changing climate could change the climate in regions at higher latitudes as well.

A dipole-like SST trend in the Somalia region during the monsoon season

Science.gov (United States)

Santos, F.; Gómez-Gesteira, M.; deCastro, M.; Días, J. M.

2015-02-01

SST trends measured in the Somalia region during the southwest monsoon season over the period 1982-2013 have shown the existence of a warming-cooling dipole. The positive spot, with a warming trend on the order of 0.37°C dec-1, is centered around 5.1°N-50.3°E and the negative one, with a trend on the order of -0.43°C dec-1, around 11.1°N-52.2°E. The migration of the Great Whirl (GW) over the last three decades at a speed of -0.3°C dec-1 in longitude and -0.6°C dec-1 in latitude was considered as the possible origin of the SST dipole. The displacement of the GW produces changes in the geostrophic currents which, in turn, generate changes in the amount of advected water from and to coast.

On the differences between early and middle winter atmospheric responses to sea surface temperature anomalies in the northwest Atlantic

International Nuclear Information System (INIS)

Peng, S.; Mysak, L.A.; Derome, J.; Ritchie, H.; Dugas, B.

1994-01-01

Using an atmospheric global spectral model at RPN with T42 horizontal resolution, we have shown that the winter atmosphere in the mid-latitude is capable of reacting to the SST anomalies prescribed in the northwest Atlantic with two different responses. The nature of the response is determined by the climatological conditions of the winter system. Experiments are conducted using either the perpetual November or January conditions, with or without the SST anomalies prescribed. Six 50-day integrations, with positive (or negative) SST anomalies prescribed, initialized from independent November analyses and similarly, four runs initialized from January analyses, have been examined in comparison with their control runs

The first experiments in SST-1

Science.gov (United States)

Pradhan, S.; Khan, Z.; Tanna, V. L.; Sharma, A. N.; Doshi, K. J.; Prasad, U.; Masand, H.; Kumar, Aveg; Patel, K. B.; Bhandarkar, M. K.; Dhongde, J. R.; Shukla, B. K.; Mansuri, I. A.; Varadarajulu, A.; Khristi, Y. S.; Biswas, P.; Gupta, C. N.; Sharma, D. K.; Raval, D. C.; Srinivasan, R.; Pandya, S. P.; Atrey, P. K.; Sharma, P. K.; Patel, P. J.; Patel, H. S.; Santra, P.; Parekh, T. J.; Dhanani, K. R.; Paravastu, Y.; Pathan, F. S.; Chauhan, P. K.; Khan, M. S.; Tank, J. K.; Panchal, P. N.; Panchal, R. N.; Patel, R. J.; George, S.; Semwal, P.; Gupta, P.; Mahesuriya, G. I.; Sonara, D. P.; Jayswal, S. P.; Sharma, M.; Patel, J. C.; Varmora, P. P.; Patel, D. J.; Srikanth, G. L. N.; Christian, D. R.; Garg, A.; Bairagi, N.; Babu, G. R.; Panchal, A. G.; Vora, M. M.; Singh, A. K.; Sharma, R.; Raju, D.; Kulkarni, S. V.; Kumar, M.; Manchanda, R.; Joisa, S.; Tahiliani, K.; Pathak, S. K.; Patel, K. M.; Nimavat, H. D.; Shah, P. R.; Chudasma, H. H.; Raval, T. Y.; Sharma, A. L.; Ojha, A.; Parghi, B. R.; Banaudha, M.; Makwana, A. R.; Chowdhuri, M. B.; Ramaiya, N.; kumar, A.; Raval, J. V.; Gupta, S.; Purohit, S.; Kaur, R.; Adhiya, A. N.; Jha, R.; Kumar, S.; Nagora, U. C.; Siju, V.; Thomas, J.; Chaudhari, V. R.; Patel, K. G.; Ambulkar, K. K.; Dalakoti, S.; Virani, C. G.; Parmar, P. R.; Thakur, A. L.; Das, A.; Bora, D.; the SST-1 Team

2015-10-01

A steady state superconducting tokamak (SST-1) has been commissioned after the successful experimental and engineering validations of its critical sub-systems. During the ‘engineering validation phase’ of SST-1; the cryostat was demonstrated to be leak-tight in all operational scenarios, 80 K thermal shields were demonstrated to be uniformly cooled without regions of ‘thermal runaway and hot spots’, the superconducting toroidal field magnets were demonstrated to be cooled to their nominal operational conditions and charged up to 1.5 T of the field at the major radius. The engineering validations further demonstrated the assembled SST-1 machine shell to be a graded, stress-strain optimized and distributed thermo-mechanical device, apart from the integrated vacuum vessel being validated to be UHV compatible etc. Subsequently, ‘field error components’ in SST-1 were measured to be acceptable towards plasma discharges. A successful breakdown in SST-1 was obtained in SST-1 in June 2013 assisted with electron cyclotron pre-ionization in the second harmonic mode, thus marking the ‘first plasma’ in SST-1 and the arrival of SST-1 into the league of contemporary steady state devices. Subsequent to the first plasma, successful repeatable plasma start-ups with E ˜ 0.4 V m-1, and plasma current in excess of 70 kA for 400 ms assisted with electron cyclotron heating pre-ionization at a field of 1.5 T have so far been achieved in SST-1. Lengthening the plasma pulse duration with lower hybrid current drive, confinement and transport in SST-1 plasmas and magnetohydrodynamic activities typical to large aspect ratio SST-1 discharges are presently being investigated in SST-1. In parallel, SST-1 has uniquely demonstrated reliable cryo-stable high field operation of superconducting TF magnets in the two-phase cooling mode, operation of vapour-cooled current leads with cold gas instead of liquid helium and an order less dc joint resistance in superconducting magnet winding

The role of SST on the South American atmospheric circulation during January, February and March 2001

Science.gov (United States)

Drumond, Anita Rodrigues De Moraes; Ambrizzi, Tércio

2005-06-01

Precipitation deficits were observed over southeastern, northeastern and Central Brazil during the 2001 Austral Summer. They contributed to the worsening of the energy crisis that was occurring in the country. A low-level anomalous anticyclonic circulation observed over eastern Brazil enhanced the deviation of moisture transport that usually occurs from the Amazon Basin to southeastern Brazil and inhibited the occurrence of South Atlantic Convergence Zone events in that period. However, an anomalous low-level northerly moisture flux was observed over the La Plata Basin, and positive precipitation anomalies occurred over Bolivia, Paraguay, northeastern Argentina and southern Brazil. Using the ensemble technique, a numerical study was carried out to investigate the role of different sea surface temperature (SST) forcings observed over this anomalous South American atmospheric circulation. Reynolds SST monthly means were used as boundary conditions to study the influence of South Atlantic, South Indian, South Pacific and Equatorial Pacific oceans. The simulations were run from September 2000 to April 2001 using the Community Climate Model version 3.6 General Circulation Model. Ten integrations using different initial conditions were done to each experiment. Numerical experiments suggested that the combined influence of South Pacific and Equatorial Pacific oceans could be responsible for the drought observed over Central Brazil. These experiments simulated the low-level anticyclonic anomaly observed over eastern Brazil. However, both experiments have poorly reproduced the intensity of the anomalous low-level northerly moisture flux observed over the La Plata Basin. Therefore, the intensity of the simulated precipitation anomalies over the subtropical regions was much weaker than observed.

Global atmospheric response to specific linear combinations of the main SST modes. Part I: numerical experiments and preliminary results

Directory of Open Access Journals (Sweden)

S. Trzaska

1996-10-01

Full Text Available This article investigates through numerical experiments the controversial question of the impact of El Niño-Southern Oscillation (ENSO phenomena on climate according to large-scale and regional-scale interhemispheric thermal contrast. Eight experiments (two considering only inversed Atlantic thermal anomalies and six combining ENSO warm phase with large-scale interhemispheric contrast and Atlantic anomaly patterns were performed with the Météo-France atmospheric general circulation model. The definition of boundary conditions from observed composites and principal components is presented and preliminary results concerning the month of August, especially over West Africa and the equatorial Atlantic are discussed. Results are coherent with observations and show that interhemispheric and regional scale sea-surface-temperature anomaly (SST patterns could significantly modulate the impact of ENSO phenomena: the impact of warm-phase ENSO, relative to the atmospheric model intercomparison project (AMIP climatology, seems stronger when embedded in global and regional SSTA patterns representative of the post-1970 conditions [i.e. with temperatures warmer (colder than the long-term mean in the southern hemisphere (northern hemisphere]. Atlantic SSTAs may also play a significant role.

The role of potential vorticity anomalies in the Somali Jet on Indian Summer Monsoon Intraseasonal Variability

Science.gov (United States)

Rai, P.; Joshi, M.; Dimri, A. P.; Turner, A. G.

2018-06-01

The climate of the Indian subcontinent is dominated by rainfall arising from the Indian summer monsoon (ISM) during June to September. Intraseasonal variability during the monsoon is characterized by periods of heavy rainfall interspersed by drier periods, known as active and break events respectively. Understanding and predicting such events is of vital importance for forecasting human impacts such as water resources. The Somali Jet is a key regional feature of the monsoon circulation. In the present study, we find that the spatial structure of Somali Jet potential vorticity (PV) anomalies varies considerably during active and break periods. Analysis of these anomalies shows a mechanism whereby sea surface temperature (SST) anomalies propagate north/northwestwards through the Arabian Sea, caused by a positive feedback loop joining anomalies in SST, convection, modification of PV by diabatic heating and mixing in the atmospheric boundary layer, wind-stress curl, and ocean upwelling processes. The feedback mechanism is consistent with observed variability in the coupled ocean-atmosphere system on timescales of approximately 20 days. This research suggests that better understanding and prediction of monsoon intraseasonal variability in the South Asian monsoon may be gained by analysis of the day-to-day dynamical evolution of PV in the Somali Jet.

The role of potential vorticity anomalies in the Somali Jet on Indian Summer Monsoon Intraseasonal Variability

Science.gov (United States)

Rai, P.; Joshi, M.; Dimri, A. P.; Turner, A. G.

2017-08-01

The climate of the Indian subcontinent is dominated by rainfall arising from the Indian summer monsoon (ISM) during June to September. Intraseasonal variability during the monsoon is characterized by periods of heavy rainfall interspersed by drier periods, known as active and break events respectively. Understanding and predicting such events is of vital importance for forecasting human impacts such as water resources. The Somali Jet is a key regional feature of the monsoon circulation. In the present study, we find that the spatial structure of Somali Jet potential vorticity (PV) anomalies varies considerably during active and break periods. Analysis of these anomalies shows a mechanism whereby sea surface temperature (SST) anomalies propagate north/northwestwards through the Arabian Sea, caused by a positive feedback loop joining anomalies in SST, convection, modification of PV by diabatic heating and mixing in the atmospheric boundary layer, wind-stress curl, and ocean upwelling processes. The feedback mechanism is consistent with observed variability in the coupled ocean-atmosphere system on timescales of approximately 20 days. This research suggests that better understanding and prediction of monsoon intraseasonal variability in the South Asian monsoon may be gained by analysis of the day-to-day dynamical evolution of PV in the Somali Jet.

68Ga-DOTATOC PET/CT and somatostatin receptor (sst1-sst5) expression in normal human tissue: correlation of sst2 mRNA and SUVmax

International Nuclear Information System (INIS)

Boy, Christian; Poeppel, Thorsten D.; Jentzen, Walter; Brandau, Wolfgang; Bockisch, Andreas; Heusner, Till A.; Antoch, Gerald; Redmann-Bischofs, Anja; Unger, Nicole; Mann, Klaus; Petersenn, Stephan

2011-01-01

By targeting somatostatin receptors (sst) radiopeptides have been established for both diagnosis and therapy. For physiologically normal human tissues the study provides a normative database of maximum standardized uptake value (SUV max ) and sst mRNA. A total of 120 patients were subjected to diagnostic 68 Ga-DOTATOC positron emission tomography (PET)/CT (age range 19-83 years). SUV max values were measured in physiologically normal tissues defined by normal morphology, absence of surgical intervention and absence of metastatic spread during clinical follow-up. Expression of sst subtypes (sst1-sst5) was measured independently in pooled adult normal human tissue by real-time reverse transcriptase polymerase chain reaction (RT-PCR). SUV max revealed a region-specific pattern (e.g., mean ± SD, spleen 31.1 ± 10.9, kidney 16.9 ± 5.3, liver 12.8 ± 3.6, stomach 7.0 ± 3.1, head of pancreas 6.2 ± 2.3, small bowel 4.8 ± 1.8, thyroid 4.7 ± 2.2, bone 3.9 ± 1.3, large bowel 2.9 ± 0.8, muscle 2.1 ± 0.5, parotid gland 1.9 ± 0.6, axillary lymph node 0.8 ± 0.3 and lung 0.7 ± 0.3). SUV max was age independent. Gender differences were evident within the thyroid (female/male: 3.7 ± 1.6/5.5 ± 2.4, p max values exclusively correlated with sst2 expression (r = 0.846, p max with the expression of the other four subtypes. In normal human tissues 68 Ga-DOTATOC imaging has been related to the expression of sst2 at the level of mRNA. The novel normative database may improve diagnostics, monitoring and therapy of sst-expressing tumours or inflammation on a molecular basis. (orig.)

Impacts of SST Patterns on Rapid Intensification of Typhoon Megi (2010)

Science.gov (United States)

Kanada, Sachie; Tsujino, Satoki; Aiki, Hidenori; Yoshioka, Mayumi K.; Miyazawa, Yasumasa; Tsuboki, Kazuhisa; Takayabu, Izuru

2017-12-01

Typhoon Megi (2010), a very intense tropical cyclone with a minimum central pressure of 885 hPa, was characterized by especially rapid intensification. We investigated this intensification process by a simulation experiment using a high-resolution (0.02° × 0.02°) three-dimensional atmosphere-ocean coupled regional model. We also performed a sensitivity experiment with a time-fixed sea surface temperature (SST). The coupled model successfully simulated the minimum central pressure of Typhoon Megi, whereas the fixed SST experiment simulated an excessively low minimum central pressure of 839 hPa. The simulation results also showed a close relationship between the radial SST profiles and the rapid intensification process. Because the warm sea increased near-surface water vapor and hence the convective available potential energy, the high SST in the eye region facilitated tall and intense updrafts inside the radius of maximum wind speed and led to the start of rapid intensification. In contrast, high SST outside this radius induced local secondary updrafts that inhibited rapid intensification even if the mean SST in the core region exceeded 29.0°C. These secondary updrafts moved inward and eventually merged with the primary eyewall updrafts. Then the storm intensified rapidly when the high SST appeared in the eye region. Thus, the changes in the local SST pattern around the storm center strongly affected the rapid intensification process by modulating the radial structure of core convection. Our results also show that the use of a high-resolution three-dimensional atmosphere-ocean coupled model offers promise for improving intensity forecasts of tropical cyclones.

The Pacific SST response to volcanic eruptions over the past millennium based on the CESM-LME

Science.gov (United States)

Man, W.; Zuo, M.

2017-12-01

The impact of the northern hemispheric, tropical and southern hemispheric volcanic eruptions on the Pacific sea surface temperature (SST) and its mechanism are investigated using the Community Earth System Model Last Millennium Ensemble. Analysis of the simulations indicates that the Pacific SST features a significant El Niño-like pattern a few months after the northern hemispheric and tropical eruptions, and with a weaker such tendency after the southern hemispheric eruptions. Furthermore, the Niño3 index peaks lagging one and a half years after the northern hemispheric and tropical eruptions. Two years after all three types of volcanic eruptions, a La Niña-like pattern over the equatorial Pacific is observed, which seems to form an El Niño-Southern Oscillation (ENSO) cycle. In addition, the westerly anomalies at 850 hPa over the western-to-central Pacific appear ahead of the warm SST; hence, the El Niño-like warming over the eastern Pacific can be attributed to the weakening of the trade winds. We further examined the causes of westerly anomalies and find that a shift of the intertropical convergence zone (ITCZ) can explain the El Niño-like response to the northern hemispheric eruptions, which is not applicable for tropical or southern hemispheric eruptions. Instead, the reduction in the zonal equatorial SST gradient through the ocean dynamical thermostat mechanism, combined with the land-sea thermal contrast between the Maritime Continent (MC) and the surrounding ocean and the divergent wind induced by the decreased precipitation over the MC, can trigger the westerly anomalies over the equatorial Pacific, which is applicable for all three types of eruptions.

El Niño indices based on subareas of SST in Pacific

Science.gov (United States)

Song, Wanjiao; Dong, Qing; Xue, Cunjin; Hou, Xueyan; Qin, Lijuan

2014-11-01

El Niño continues the most important coupled ocean-atmosphere phenomenon to cause global climate variability on seasonal to inter annual time scales. The first independent spatial mode which carried out by EOF analysis of tropical and north Pacific sea surface temperature (SST) for the period of 1985-2009 in AVHRR dataset is found to be associated with well-known regional climate phenomena: the El Niño. This paper addresses the need for a reliable El Niño index that allows for the historical definition of El Niño events in the instrumental record back to 1985-2009 with a new perspective. For quantitative purposes, possible definitions are explored that match the El Niño identified historically in 1985-2009, and it is suggested that an El Niño can be said to occur if difference of sea surface temperature (SST) anomalies between the tropical and north Pacific exceeds 0.6 times standard deviation for 5 months or more. An advantage of such a definition is that it combines the characteristics between tropical and north Pacific. Through seasonal analysis of SST in El Niño event, we found that the El Niño events are almost beginning in boreal spring or perhaps boreal summer and peak from November to February. It provides a more complete and flexible description of the El Niño phenomenon than single area in tropical Pacific.

Remote and Local Influences in Forecasting Pacific SST: a Linear Inverse Model and a Multimodel Ensemble Study

Science.gov (United States)

Faggiani Dias, D.; Subramanian, A. C.; Zanna, L.; Miller, A. J.

2017-12-01

Sea surface temperature (SST) in the Pacific sector is well known to vary on time scales from seasonal to decadal, and the ability to predict these SST fluctuations has many societal and economical benefits. Therefore, we use a suite of statistical linear inverse models (LIMs) to understand the remote and local SST variability that influences SST predictions over the North Pacific region and further improve our understanding on how the long-observed SST record can help better guide multi-model ensemble forecasts. Observed monthly SST anomalies in the Pacific sector (between 15oS and 60oN) are used to construct different regional LIMs for seasonal to decadal prediction. The forecast skills of the LIMs are compared to that from two operational forecast systems in the North American Multi-Model Ensemble (NMME) revealing that the LIM has better skill in the Northeastern Pacific than NMME models. The LIM is also found to have comparable forecast skill for SST in the Tropical Pacific with NMME models. This skill, however, is highly dependent on the initialization month, with forecasts initialized during the summer having better skill than those initialized during the winter. The forecast skill with LIM is also influenced by the verification period utilized to make the predictions, likely due to the changing character of El Niño in the 20th century. The North Pacific seems to be a source of predictability for the Tropics on seasonal to interannual time scales, while the Tropics act to worsen the skill for the forecast in the North Pacific. The data were also bandpassed into seasonal, interannual and decadal time scales to identify the relationships between time scales using the structure of the propagator matrix. For the decadal component, this coupling occurs the other way around: Tropics seem to be a source of predictability for the Extratropics, but the Extratropics don't improve the predictability for the Tropics. These results indicate the importance of temporal

Tropical cyclone cooling combats region-wide coral bleaching.

Science.gov (United States)

Carrigan, Adam D; Puotinen, Marji

2014-05-01

Coral bleaching has become more frequent and widespread as a result of rising sea surface temperature (SST). During a regional scale SST anomaly, reef exposure to thermal stress is patchy in part due to physical factors that reduce SST to provide thermal refuge. Tropical cyclones (TCs - hurricanes, typhoons) can induce temperature drops at spatial scales comparable to that of the SST anomaly itself. Such cyclone cooling can mitigate bleaching across broad areas when well-timed and appropriately located, yet the spatial and temporal prevalence of this phenomenon has not been quantified. Here, satellite SST and historical TC data are used to reconstruct cool wakes (n=46) across the Caribbean during two active TC seasons (2005 and 2010) where high thermal stress was widespread. Upon comparison of these datasets with thermal stress data from Coral Reef Watch and published accounts of bleaching, it is evident that TC cooling reduced thermal stress at a region-wide scale. The results show that during a mass bleaching event, TC cooling reduced thermal stress below critical levels to potentially mitigate bleaching at some reefs, and interrupted natural warming cycles to slow the build-up of thermal stress at others. Furthermore, reconstructed TC wave damage zones suggest that it was rare for more reef area to be damaged by waves than was cooled (only 12% of TCs). Extending the time series back to 1985 (n = 314), we estimate that for the recent period of enhanced TC activity (1995-2010), the annual probability that cooling and thermal stress co-occur is as high as 31% at some reefs. Quantifying such probabilities across the other tropical regions where both coral reefs and TCs exist is vital for improving our understanding of how reef exposure to rising SSTs may vary, and contributes to a basis for targeting reef conservation. © 2014 John Wiley & Sons Ltd.

Changes in the interannual SST-forced signals on West African rainfall. AGCM intercomparison

Energy Technology Data Exchange (ETDEWEB)

Mohino, Elsa [LOCEAN/IPSL, Universite Pierre et Marie Curie, Paris Cedex 05 (France); Universidad de Sevilla, Sevilla (Spain); Rodriguez-Fonseca, Belen [Universidad Complutense de Madrid, Dpto. Geofisica y Meteorologia, Madrid (Spain); Instituto de Geociencias (CSIC-UCM), Madrid (Spain); Losada, Teresa [Universidad Complutense de Madrid, Dpto. Geofisica y Meteorologia, Madrid (Spain); Gervois, Sebastien [LOCEAN/IPSL, Universite Pierre et Marie Curie, Paris Cedex 05 (France); Janicot, Serge [LOCEAN/IPSL, IRD, Universite Pierre et Marie Curie, Paris (France); Bader, Juergen [Bjerknes Centre for Climate Research, Bergen (Norway); Ruti, Paolo [Progetto Speciale Clima Globale, Ente Nazionale per le Nuove Tecnologie, l' Energia e l' Ambiente, Rome (Italy); Chauvin, Fabrice [GAME/CNRM, Meteo-France/CNRS, Toulouse (France)

2011-11-15

Rainfall over West Africa shows strong interannual variability related to changes in Sea Surface Temperature (SST). Nevertheless, this relationship seem to be non-stationary. A particular turning point is the decade of the 1970s, which witnessed a number of changes in the climatic system, including the climate shift of the late 1970s. The first aim of this study is to explore the change in the interannual variability of West African rainfall after this shift. The analysis indicates that the dipolar features of the rainfall variability over this region, related to changes in the Atlantic SST, disappear after this period. Also, the Pacific SST variability has a higher correlation with Guinean rainfall in the recent period. The results suggest that the current relationship between the Atlantic and Pacific El Nino phenomena is the principal responsible for these changes. A fundamental goal of climate research is the development of models simulating a realistic current climate. For this reason, the second aim of this work is to test the performance of Atmospheric General Circulation models in simulating rainfall variability over West Africa. The models have been run with observed SSTs for the common period 1957-1998 as part of an intercomparison exercise. The results show that the models are able to reproduce Guinean interannual variability, which is strongly related to SST variability in the Equatorial Atlantic. Nevertheless, problems in the simulation of the Sahelian interannual variability appear: not all models are able to reproduce the observed negative link between rainfall over the Sahel and El Nino-like anomalies in the Pacific, neither the positive correlation between Mediterranean SSTs and Sahelian rainfall. (orig.)

The role of SST variability in the simulation of the MJO

Science.gov (United States)

Stan, Cristiana

2017-12-01

The sensitivity of the Madden-Julian Oscillation to high-frequency variability (period 1-5 days) of sea surface temperature (SST) is investigated using numerical experiments with the super-parameterized Community Climate System Model. The findings of this study emphasize the importance of air-sea interactions in the simulation of the MJO, and stress the necessity of an accurate representation of ocean variability on short time scales. Eliminating 1-5-day variability of surface boundary forcing reduces the intraseasonal variability (ISV) of the tropics during the boreal winter. The ISV spectrum becomes close to the red noise background spectrum. The variability of atmospheric circulation shifts to longer time scales. In the absence of high-frequency variability of SST the MJO power gets confined to wavenumbers 1-2 and the magnitude of westward power associated with Rossby waves increases. The MJO convective activity propagating eastward from the Indian Ocean does not cross the Maritime Continent, and convection in the western Pacific Ocean is locally generated. In the Indian Ocean convection tends to follow the meridional propagation of SST anomalies. The response of the MJO to 1-5-day variability in the SST is through the charging and discharging mechanisms contributing to the atmospheric column moist static energy before and after peak MJO convection. Horizontal advection and surface fluxes show the largest sensitivity to SST perturbations.

Investigating the sensitivity of hurricane intensity and trajectory to sea surface temperatures using the regional model WRF

Directory of Open Access Journals (Sweden)

Cevahir Kilic

2013-12-01

Full Text Available The influence of sea surface temperature (SST anomalies on the hurricane characteristics are investigated in a set of sensitivity experiments employing the Weather Research and Forecasting (WRF model. The idealised experiments are performed for the case of Hurricane Katrina in 2005. The first set of sensitivity experiments with basin-wide changes of the SST magnitude shows that the intensity goes along with changes in the SST, i.e., an increase in SST leads to an intensification of Katrina. Additionally, the trajectory is shifted to the west (east, with increasing (decreasing SSTs. The main reason is a strengthening of the background flow. The second set of experiments investigates the influence of Loop Current eddies idealised by localised SST anomalies. The intensity of Hurricane Katrina is enhanced with increasing SSTs close to the core of a tropical cyclone. Negative nearby SST anomalies reduce the intensity. The trajectory only changes if positive SST anomalies are located west or north of the hurricane centre. In this case the hurricane is attracted by the SST anomaly which causes an additional moisture source and increased vertical winds.

U.S. West Coast MODIS Aqua High Resolution CHLA Anomaly Fields (July 2002 - March 2014)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This suite of CHLA and SST climatology and anomaly data products are derived from daily, 0.0125 degree x 0.0125 degree, MODIS Aqua CHLA and SST fields that cover the...

Global Monitoring RSEM System for Crop Production by Incorporating Satellite-based Photosynthesis Rates and Anomaly Data of Sea Surface Temperature

Science.gov (United States)

Kaneko, D.; Sakuma, H.

2014-12-01

The first author has been developing RSEM crop-monitoring system using satellite-based assessment of photosynthesis, incorporating meteorological conditions. Crop production comprises of several stages and plural mechanisms based on leaf photosynthesis, surface energy balance, and the maturing of grains after fixation of CO2, along with water exchange through soil vegetation-atmosphere transfer. Grain production in prime countries appears to be randomly perturbed regionally and globally. Weather for crop plants reflects turbulent phenomena of convective and advection flows in atmosphere and surface boundary layer. It has been difficult for scientists to simulate and forecast weather correctly for sufficiently long terms to crop harvesting. However, severely poor harvests related to continental events must originate from a consistent mechanism of abnormal energetic flow in the atmosphere through both land and oceans. It should be remembered that oceans have more than 100 times of energy storage compared to atmosphere and ocean currents represent gigantic energy flows, strongly affecting climate. Anomalies of Sea Surface Temperature (SST), globally known as El Niño, Indian Ocean dipole, and Atlantic Niño etc., affect the seasonal climate on a continental scale. The authors aim to combine monitoring and seasonal forecasting, considering such mechanisms through land-ocean biosphere transfer. The present system produces assessments for all continents, specifically monitoring agricultural fields of main crops. Historical regions of poor and good harvests are compared with distributions of SST anomalies, which are provided by NASA GSFC. Those comparisons fairly suggest that the Worst harvest in 1993 and the Best in 1994 relate to the offshore distribution of low temperature anomalies and high gaps in ocean surface temperatures. However, high-temperature anomalies supported good harvests because of sufficient solar radiation for photosynthesis, and poor harvests because

Congenital anomalies in Primorsky region.

Science.gov (United States)

Kiku, P; Voronin, S; Golokhvast, K

2015-01-01

According to WHO hereditary diseases and congenital malformations contribute significantly to the health of population. Thus, the problems of epidemiology, clinical presentation, diagnosis and treatment of congenital abnormalities are of interest for many researchers [2]. In addition, the dynamic accounting for the incidence of congenital malformations and hereditary diseases allows the researchers to assess the ecological situation in the region [1]. The occurrence of congenital anomalies in the world varies; it depends heavily on how carefully the data is collected [4]. Multifactorial or polygenic diseases develop under the influence of environmental factors in the presence of defective genes. They can constitute up to 90% of all chronic pathology [2-5]. To determine the incidence of congenital anomalies under the influence of environmental factors. The study used the methodology of system evaluation of congenital anomalies incidence in Primorsky region, depending on bio-climatic and environmental conditions. The authors used health statistics for the period from 2000 to 2014, F.12 class for congenital abnormalities in adolescents and children that were compared in geographical and temporal aspects with environmental factors of 33 settlements in Primorsky region. The environment is represented by nature and climate (6 factor modules) and sanitation (7 factor modules) blocks of factors. When formalizing the information database of the environment a specially developed 10-point assessment scale was used. Statistical processing of the information was carried out using Pearson's chi-squared test and multiple regression method from SSPS application program package. The study found that over the 15-year period the level of congenital abnormalities in children increased by 27.5% and in adolescents - by 35.1%, and in 2014 it amounted to 1687.6 and 839.3 per 100 000 people, respectively. The predictive model shows a steady further growth of this pathology. The incidence

Air-sea heat fluxes associated to mesoscale eddies in the Southwestern Atlantic Ocean and their dependence on different regional conditions

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Leyba, Inés M.; Saraceno, Martín; Solman, Silvina A.

2017-10-01

Heat fluxes between the ocean and the atmosphere largely represent the link between the two media. A possible mechanism of interaction is generated by mesoscale ocean eddies. In this work we evaluate if eddies in Southwestern Atlantic (SWA) Ocean may significantly affect flows between the ocean and the atmosphere. Atmospherics conditions associated with eddies were examined using data of sea surface temperature (SST), sensible (SHF) and latent heat flux (LHF) from NCEP-CFSR reanalysis. On average, we found that NCEP-CFSR reanalysis adequately reflects the variability expected from eddies in the SWA, considering the classical eddy-pumping theory: anticyclonic (cyclonic) eddies cause maximum positive (negative) anomalies with maximum mean anomalies of 0.5 °C (-0.5 °C) in SST, 6 W/m2 (-4 W/m2) in SHF and 12 W/m2 (-9 W/m2) in LHF. However, a regional dependence of heat fluxes associated to mesoscale cyclonic eddies was found: in the turbulent Brazil-Malvinas Confluence (BMC) region they are related with positive heat flux anomaly (ocean heat loss), while in the rest of the SWA they behave as expected (ocean heat gain). We argue that eddy-pumping do not cool enough the center of the cyclonic eddies in the BMC region simply because most of them trapped very warm waters when they originate in the subtropics. The article therefore concludes that in the SWA: (1) a robust link exists between the SST anomalies generated by eddies and the local anomalous heat flow between the ocean and the atmosphere; (2) in the BMC region cyclonic eddies are related with positive heat anomalies, contrary to what is expected.

Sensitive study of the climatological SST by using ATSR global SST data sets

Science.gov (United States)

Xue, Yong; Lawrence, Sean P.; Llewellyn-Jones, David T.

1995-12-01

Climatological sea surface temperature (SST) is an initial step for global climate processing monitoring. A comparison has been made by using Oberhuber's SST data set and two years monthly averaged SST from ATSR thermal band data to force the OGCM. In the eastern Pacific Ocean, these make only a small difference to model SST. In the western Pacific Ocean, the use of Oberhuber's data set gives higher climatological SST than that using ATSR data. The SSTs were also simulated for 1992 using climatological SSTs from two years monthly averaged ATSR data and Oberhuber data. The forcing with SST from ATSR data was found to give better SST simulation than that from Oberhuber's data. Our study has confirmed that ATSR can provide accurate monthly averaged global SST for global climate processing monitoring.

Shallow Drilling In The Salton Sea Region, The Thermal Anomaly

Energy Technology Data Exchange (ETDEWEB)

Newmark, R. L.; Kasameyer, P. W.; Younker, L. W.

1987-01-01

During two shallow thermal drilling programs, thermal measurements were obtained in 56 shallow (76.2 m) and one intermediate (457.3 m) depth holes located both onshore and offshore along the southern margin of the Salton Sea in the Imperial Valley, California. These data complete the surficial coverage of the thermal anomaly, revealing the shape and lateral extent of the hydrothermal system. The thermal data show the region of high thermal gradients to extend only a short distance offshore to the north of the Quaternary volcanic domes which are exposed along the southern shore of the Salton Sea. The thermal anomaly has an arcuate shape, about 4 km wide and 12 km long. Across the center of the anomaly, the transition zone between locations exhibiting high thermal gradients and those exhibiting regional thermal gradients is quite narrow. Thermal gradients rise from near regional (0.09 C/m) to extreme (0.83 C/m) in only 2.4 km. The heat flow in the central part of the anomaly is >600 mW/m{sup 2} and in some areas exceeds 1200 mW/m{sup 2}. The shape of the thermal anomaly is asymmetric with respect to the line of volcanoes previously thought to represent the center of the field, with its center line offset south of the volcanic buttes. There is no broad thermal anomaly associated with the magnetic high that extends offshore to the northeast from the volcanic domes. These observations of the thermal anomaly provide important constraints for models of the circulation of the hydrothermal system. Thermal budgets based on a simple model for this hydrothermal system indicate that the heat influx rate for local ''hot spots'' in the region may be large enough to account for the rate of heat flux from the entire Salton Trough.

Roles of tropical SST patterns during two types of ENSO in modulating wintertime rainfall over southern China

Science.gov (United States)

Xu, Kang; Huang, Qing-Lan; Tam, Chi-Yung; Wang, Weiqiang; Chen, Sheng; Zhu, Congwen

2018-03-01

The impacts of the eastern-Pacific (EP) and central-Pacific (CP) El Niño-Southern Oscillation (ENSO) on the southern China wintertime rainfall (SCWR) have been investigated. Results show that wintertime rainfall over most stations in southern China is enhanced (suppressed) during the EP (CP) El Niño, which are attributed to different atmospheric responses in the western North Pacific (WNP) and South China Sea (SCS) during two types of ENSO. When EP El Niño occurs, an anomalous low-level anticyclone is present over WNP/the Philippines region, resulting in stronger-than-normal southwesterlies over SCS. Such a wind branch acts to suppress East Asian winter monsoon (EAWM) and enhance moisture supply, implying surplus SCWR. During CP El Niño, however, anomalous sinking and low-level anticyclonic flow are found to cover a broad region in SCS. These circulation features are associated with moisture divergence over the northern part of SCS and suppressed SCWR. General circulation model experiments have also been conducted to study influence of various tropical sea surface temperature (SST) patterns on the EAWM atmospheric circulation. For EP El Niño, formation of anomalous low-level WNP anticyclone is jointly attributed to positive/negative SST anomalies (SSTA) over the central-to-eastern/ western equatorial Pacific. However, both positive and negative CP Niño-related-SSTA, located respectively over the central Pacific and WNP/SCS, offset each other and contribute a weak but broad-scale anticyclone centered at SCS. These results suggest that, besides the vital role of SST warming, SST cooling over SCS/WNP during two types of El Niño should be considered carefully for understanding the El Niño-EAWM relationship.

Intraseasonal variability in the far-east pacific: investigation of the role of air-sea coupling in a regional coupled model

Energy Technology Data Exchange (ETDEWEB)

Small, R.J. [Naval Research Laboratory, Jacobs Technology, Stennis Space Center, MS (United States); University of Hawaii, International Pacific Research Center, POST 401, Honolulu, HI (United States); Xie, Shang-Ping [University of Hawaii, International Pacific Research Center, POST 401, Honolulu, HI (United States); University of Hawaii, Department of Meteorology, School of Ocean and Earth Science and Technology, Honolulu, HI (United States); Maloney, Eric D. [Colorado State University, Department of Atmospheric Science, Fort Collins, CO (United States); Szoeke, Simon P. de [Oregon State University, College of Oceanic and Atmospheric Sciences, Corvallis, OR (United States); Miyama, Toru [Frontier Research for Global Change, Yokohama (Japan)

2011-03-15

Intraseasonal variability in the eastern Pacific warm pool in summer is studied, using a regional ocean-atmosphere model, a linear baroclinic model (LBM), and satellite observations. The atmospheric component of the model is forced by lateral boundary conditions from reanalysis data. The aim is to quantify the importance to atmospheric deep convection of local air-sea coupling. In particular, the effect of sea surface temperature (SST) anomalies on surface heat fluxes is examined. Intraseasonal (20-90 day) east Pacific warm-pool zonal wind and outgoing longwave radiation (OLR) variability in the regional coupled model are correlated at 0.8 and 0.6 with observations, respectively, significant at the 99% confidence level. The strength of the intraseasonal variability in the coupled model, as measured by the variance of outgoing longwave radiation, is close in magnitude to that observed, but with a maximum located about 10 further west. East Pacific warm pool intraseasonal convection and winds agree in phase with those from observations, suggesting that remote forcing at the boundaries associated with the Madden-Julian oscillation determines the phase of intraseasonal convection in the east Pacific warm pool. When the ocean model component is replaced by weekly reanalysis SST in an atmosphere-only experiment, there is a slight improvement in the location of the highest OLR variance. Further sensitivity experiments with the regional atmosphere-only model in which intraseasonal SST variability is removed indicate that convective variability has only a weak dependence on the SST variability, but a stronger dependence on the climatological mean SST distribution. A scaling analysis confirms that wind speed anomalies give a much larger contribution to the intraseasonal evaporation signal than SST anomalies, in both model and observations. A LBM is used to show that local feedbacks would serve to amplify intraseasonal convection and the large-scale circulation. Further

The interdecadal change in the intensity of interannual variation of spring precipitation over southern China and its relationship with the SST anomaly

Science.gov (United States)

Qiao, Y.; Xu, C.

2017-12-01

Based on the observed precipitation data from 756 China stations, ERA-interim reanalysis dataset, and HadISST dataset for 1979-2014, this paper investigates the intensity of interannual variation (IIV) of spring precipitation over southern China during 1979-2014 and related large-scale atmospheric and oceanic signal through empirical orthogonal function (EOF) method and other statistical analysis methods. The results show that the IIV of spring precipitation over South China (SC) was stronger during 1979-1994, which is related to the spring western Pacific (WP) sea surface temperature anomaly (SSTA) and the previous winter South Pacific tripole (SPT) pattern of SSTA. Anomalous cooler (warmer) WP SSTA triggers anomalous descending (ascending) motion and lower-level anticyclone (cyclone), which in turn induces anomalous ascent (descent) over SC through an anomalous vertical circulation. The SPT can influence the spring precipitation over SC by impacting WP SST. The stronger IIV of WP SST and SPT led to an intensified IIV of spring rainfall over SC. The IIV of spring precipitation over middle and lower reaches of the Yangtze River (YZR) was more intense during 1995-2006. The intensified interannual variability of spring rainfall over YZR is interrelated with the increase in the amplitude of the spring southern Indian Ocean dipole (SIOD) in early 1990s. During the positive (negative) SIOD, the western Pacific subtropical high (WPSH) is stronger (weaker), which is favorable (unfavorable) for the transportation of vapor from Pacific to YZR. At the same time, the pressure ridge over Siberia and East Asian trough is weaker (stronger), enhancing (weakening) the spring precipitation over YZR.

The Mg - SST relationship in mollusc shells: is there a rule? Examples from three tropical species

Science.gov (United States)

Lazareth, C. E.; Guzmán, N.; Lecornec, F.; Cabioch, G.; Ortlieb, L.

2009-04-01

carried out on the external aragonitic shell layer of T. squamosa showed that, over 14 months of growth, Mg and SST are well conversely correlated but the seasonal cycle is interrupted by a Mg peak that corresponds to a shell growth anomaly. Additional studies, especially dedicated on anomalies-related Mg increases, must be performed to validate the T. squamosa shell as a reliable SST proxy. Considering previous works and the results presented here, one can definitively conclude that, at least, calibration procedures are indispensable before using Mg as a SST proxy in mollusc shells. In addition, further work specifically directed towards the role of the metabolism on the incorporation of Mg in mollusc shells could be the key to understand, and thus to use, this proxy for which, at the present time, no single rule is applicable to molluscs. Contribution of the CONCHAS (PNEDC), CENSOR (6th PCRD) and BioCalc (ESF) projects. "This study was financed and conducted in the frame of the EU-project CENSOR (Climate variability and El Nino Southern Oscillation: Impacts for natural resources and management, contract 511071) and is CENSOR publication 0375".

Pattern Analysis of El Nino and La Nina Phenomenon Based on Sea Surface Temperature (SST) and Rainfall Intensity using Oceanic Nino Index (ONI) in West Java Area

Science.gov (United States)

Prasetyo, Yudo; Nabilah, Farras

2017-12-01

Climate change occurs in 1998-2016 brings significant alteration in the earth surface. It is affects an extremely anomaly temperature such as El Nino and La Nina or mostly known as ENSO (El Nino Southern Oscillation). West Java is one of the regions in Indonesia that encounters the impact of this phenomenon. Climate change due to ENSO also affects food production and other commodities. In this research, processing data method is conducted using programming language to process SST data and rainfall data from 1998 to 2016. The data are sea surface temperature from NOAA satellite, SST Reynolds (Sea Surface Temperature) and daily rainfall temperature from TRMM satellite. Data examination is done using analysis of rainfall spatial pattern and sea surface temperature (SST) where is affected by El Nino and La Nina phenomenon. This research results distribution map of SST and rainfall for each season to find out the impacts of El Nino and La Nina around West Java. El Nino and La Nina in Java Sea are occurring every August to February. During El Nino, sea surface temperature is between 27°C - 28°C with average temperature on 27.71°C. Rainfall intensity is 1.0 mm/day - 2.0 mm/day and the average are 1.63 mm/day. During La Nina, sea surface temperature is between 29°C - 30°C with average temperature on 29.06°C. Rainfall intensity is 9.0 mm/day - 10 mm/day, and the average is 9.74 mm/day. The correlation between rainfall and SST is 0,413 which is expresses a fairly strong correlation between parameters. The conclusion is, during La Nina SST and rainfall increase. While during El Nino SST and rainfall decrease. Hopefully this research could be a guideline to plan disaster mitigation in West Java region that is related extreme climate change.

A Tropical View of Atlantic Multidecadal SST Variability over the Last Two Millennia

Science.gov (United States)

Wurtzel, J. B.; Black, D. E.; Thunell, R.; Peterson, L. C.; Tappa, E. J.; Rahman, S.

2011-12-01

Instrumental and proxy-reconstructions show the existence of a 60-80 year periodicity in Atlantic sea surface temperature (SST), known as the Atlantic Multidecadal Oscillation (AMO). The AMO is correlated with circum-tropical Atlantic climate phenomena such as Sahel and Nordeste rainfall, as well as Atlantic hurricane patterns. Though it has been suggested that the AMO is controlled by thermohaline circulation, much debate exists as to whether the SST fluctuations are a result of anthropogenic forcing or natural climate variability. Our ability to address this issue has been limited by instrumental SST records that rarely extend back more than 50-100 years and proxy reconstructions that are largely terrestrial-based. Here we present a high-resolution marine sediment-derived reconstruction of seasonal tropical Atlantic SSTs from the Cariaco Basin spanning the past two millennia that is correlated with instrumental SSTs and the AMO for the period of overlap. The full record demonstrates that seasonality is largely controlled by variations in winter/spring SST. Wavelet analysis of the proxy data suggest that variability in the 60-80 year band evolved 250 years ago, while 40-60 year periodicities dominate earlier parts of the record. At least over the last millennia, multidecadal- and centennial- scale SST variability in the tropical Atlantic appears related to Atlantic meridional overturning circulation (AMOC) fluctuations and its associated northward heat transport that in turn may be driven by solar variability. An inverse correlation between the tropical proxy annual average SST record and Δ14C indicates that the tropics experienced positive SST anomalies during times of reduced solar activity, possibly as a result of decreased AMOC strength (Figure 1).

Coupled ocean-atmosphere surface variability and its climate impacts in the tropical Atlantic region

Science.gov (United States)

Fontaine, B.; Janicot, Serge; Roucou, P.

This study examines time evolution and statistical relationships involving the two leading ocean-atmosphere coupled modes of variability in the tropical Atlantic and some climate anomalies over the tropical 120°W-60°W region using selected historical files (75-y near global SSTs and precipitation over land), more recent observed data (30-y SST and pseudo wind stress in the tropical Atlantic) and reanalyses from the US National Centers for Environmental Prediction (NCEP/NCAR) reanalysis System on the period 1968-1997: surface air temperature, sea level pressure, moist static energy content at 850 hPa, precipitable water and precipitation. The first coupled mode detected through singular value decomposition of the SST and pseudo wind-stress data over the tropical Atlantic (30°N-20°S) expresses a modulation in the thermal transequatorial gradient of SST anomalies conducted by one month leading wind-stress anomalies mainly in the tropical north Atlantic during northern winter and fall. It features a slight dipole structure in the meridional plane. Its time variability is dominated by a quasi-decadal signal well observed in the last 20-30 ys and, when projected over longer-term SST data, in the 1920s and 1930s but with shorter periods. The second coupled mode is more confined to the south-equatorial tropical Atlantic in the northern summer and explains considerably less wind-stress/SST cross-covariance. Its time series features an interannual variability dominated by shorter frequencies with increased variance in the 1960s and 1970s before 1977. Correlations between these modes and the ENSO-like Nino3 index lead to decreasing amplitude of thermal anomalies in the tropical Atlantic during warm episodes in the Pacific. This could explain the nonstationarity of meridional anomaly gradients on seasonal and interannual time scales. Overall the relationships between the oceanic component of the coupled modes and the climate anomaly patterns denote thermodynamical

Interdecadal change in the summer SST-precipitation relationship around the late 1990s over the South China Sea

Science.gov (United States)

Chen, Jiepeng; Wang, Xin; Zhou, Wen; Wen, Zhiping

2017-11-01

An interdecadal change in the air-sea interaction over the South China Sea (SCS) after the late 1990s has been identified using a local contemporaneous precipitation-sea surface temperature (SST) and precipitation-SST tendency relationship. During 1979-1998, there is a negative precipitation-SST relationship over the SCS, with a larger magnitude over the northeastern SCS (NESCS) than over the southwestern SCS (SWSCS). The remote effect of warmer SST over the tropical Indian Ocean plays a crucial role in a strong anticyclone and suppressed rainfall over the SCS and western North Pacific. Due to greater mixed-layer depth over the SWSCS than over the NESCS, entrainment heat flux makes a larger contribution to a positive precipitation-SST tendency over the SWSCS than over the NESCS. The cloud-radiation effect has a dominant and positive contribution to the SST tendency over the NESCS, whereas it has a negative contribution to SST tendency over the SWSCS. In contrast, the precipitation-SST correlation becomes weakly negative over the NESCS and significantly positive over the SWSCS during 1999-2013. The CESM-CAM5 model demonstrates that cooler SST over the tropical central-eastern Pacific (TCEP) triggers a weak anticyclone, slightly suppressing rainfall over the SCS. The cloud-radiation effect still contributes mostly to a positive SST tendency over the NESCS. Warmer SST over the SWSCS induces an increase in surface evaporation and low-level moisture convergence and causes enhanced rainfall. That offsets the remote effect of TCEP SST and results in a negative precipitation-SST tendency with negative cloud-radiation feedback. The interdecadal change in remote forcing to SCS rainfall around the late 1990s is related to the evolution of TCEP SST anomalies from the preceding winter to summer, which is possibly modulated by the phase of the Pacific Decadal Oscillation.

Probing the earth's gravity field using Satellite-to-Satellite Tracking (SST)

Science.gov (United States)

Vonbun, F. O.

1976-01-01

Satellite-to-Satellite (SST) tests, namely: (a) the ATS-6/GEOS-3 and (b) the ATS-6/Apollo-Soyuz experiment and some of the results obtained are described. The main purpose of these two experiments was first to track via ATS-6 the GEOS-3 as well as the Apollo-Soyuz and to use these tracking data to determine (a) both orbits, that is, ATS-6, GEOS-3 and/or the Apollo-Soyuz orbits at the same time; (b) each of these orbits alone; and (c) test the ATS-6/GEOS-3 and/or Apollo-Soyuz SST link to study local gravity anomalies; and, second, to test communications, command, and data transmission from the ground via ATS-6 to these spacecraft and back again to the ground. The Apollo-Soyuz Geodynamics Experiment is discussed in some detail.

Penentuan Anomali Gayaberat Regional dan Residual Menggunakan Filter Gaussian Daerah Mamuju Sulawesi Barat

Directory of Open Access Journals (Sweden)

Adhika Junara Karunianto

2017-11-01

Full Text Available Gravity method is a geophysical method that has been frequently used in prospecting mineral resources. The parameter of searched object is based on variations of gravity acceleration measurements on the surface due to variations in sub-surface geological changes. Research area is located in Mamuju Area of West Sulawesi Province where tectonically a complex geological region, which is at a meeting of three large plates, the Pacific plate, the Indo-Australian plate and the Eurasian plate and the smaller Philippine plate. In addition, Mamuju is an area with a high radioactivity dose rate that has potency to radioactive minerals resources. The purpose of the research is to obtain gravity anomalies by using qualitative separation and interpretation of regional and residual gravity anomalies. Complete Bouguer Anomaly (CBA value of the research area obtained from the measurements was 46.0 – 115.7 mGal. Based on the CBA map, the separation process of regional gravity anomalies and residual using Gaussian filtering technique conducted. This filtering technique works based on spectral analysis of gravity amplitude changes in spatial where the result is a cutoff wave number of 1.1736 x 10-3/meter and a wavelength of 5373.45 m. The regional and residual gravity anomalies range from 51.8 to 102 mGal and -10.4 to 14.8 mGal respectively. The depth of influence of each anomaly is calculated based on their spectral wavelengths, resulting 970.97 m and 100.21 m for regional and residual anomalies respectively. There are five zones based on the residual anomaly map, which are zones A, B, C, D and E. The heaviest positive gravity anomaly is found in zone A and B, which is predicted to be influenced by Adang lava with relative north – south distribution.

LUMBAR: association between cutaneous infantile hemangiomas of the lower body and regional congenital anomalies.

Science.gov (United States)

Iacobas, Ionela; Burrows, Patricia E; Frieden, Ilona J; Liang, Marilyn G; Mulliken, John B; Mancini, Anthony J; Kramer, Daniela; Paller, Amy S; Silverman, Robert; Wagner, Annette M; Metry, Denise W

2010-11-01

To define the clinical spectrum of regional congenital anomalies associated with large cutaneous hemangiomas of the lower half of the body, clarify risk for underlying anomalies on the basis of hemangioma location, and provide imaging guidelines for evaluation. We conducted a multi-institutional, retrospective case analysis of 24 new patients and review of 29 published cases. Hemangiomas in our series tended to be "segmental" and often "minimal growth" in morphology. Such lesions were often extensive, covering the entire leg. Extensive limb hemangiomas also showed potential for extracutaneous anomalies, including underlying arterial anomalies, limb underdevelopment, and ulceration. The cutaneous hemangioma and underlying anomalies demonstrated regional correlation. Myelopathies were the most common category of associated anomalies. We propose the acronym "LUMBAR" to describe the association of Lower body hemangioma and other cutaneous defects, Urogenital anomalies, Ulceration, Myelopathy, Bony deformities, Anorectal malformations, Arterial anomalies, and Renal anomalies. There are many similarities between LUMBAR and PHACE syndrome, which might be considered regional variations of the same. Although guidelines for imaging are suggested, prospective studies will lead to precise imaging recommendations and help determine true incidence, risk and long-term outcomes. Copyright © 2010 Mosby, Inc. All rights reserved.

Quantifying uncertainty in coral Sr/Ca-based SST estimates from Orbicella faveolata: A basis for multi-colony SST reconstructions

Science.gov (United States)

Richey, J. N.; Flannery, J. A.; Toth, L. T.; Kuffner, I. B.; Poore, R. Z.

2017-12-01

The Sr/Ca in massive corals can be used as a proxy for sea surface temperature (SST) in shallow tropical to sub-tropical regions; however, the relationship between Sr/Ca and SST varies throughout the ocean, between different species of coral, and often between different colonies of the same species. We aimed to quantify the uncertainty associated with the Sr/Ca-SST proxy due to sample handling (e.g., micro-drilling or analytical error), vital effects (e.g., among-colony differences in coral growth), and local-scale variability in microhabitat. We examine the intra- and inter-colony reproducibility of Sr/Ca records extracted from five modern Orbicella faveolata colonies growing in the Dry Tortugas, Florida, USA. The average intra-colony absolute difference (AD) in Sr/Ca of the five colonies during an overlapping interval (1997-2008) was 0.055 ± 0.044 mmol mol-1 (0.96 ºC) and the average inter-colony Sr/Ca AD was 0.039 ± 0.01 mmol mol-1 (0.51 ºC). All available Sr/Ca-SST data pairs from 1997-2008 were combined and regressed against the HadISST1 gridded SST data set (24 ºN and 82 ºW) to produce a calibration equation that could be applied to O. faveolata specimens from throughout the Gulf of Mexico/Caribbean/Atlantic region after accounting for the potential uncertainties in Sr/Ca-derived SSTs. We quantified a combined error term for O. faveolata using the root-sum-square (RMS) of the analytical, intra-, and inter-colony uncertainties and suggest that an overall uncertainty of 0.046 mmol mol-1 (0.81 ºC, 1σ), should be used to interpret Sr/Ca records from O. faveolata specimens of unknown age or origin to reconstruct SST. We also explored how uncertainty is affected by the number of corals used in a reconstruction by iteratively calculating the RMS error for composite coral time-series using two, three, four, and five overlapping coral colonies. Our results indicate that maximum RMS error at the 95% confidence interval on mean annual SST estimates is 1.4 º

Two-dimensional finite difference model to study temperature distribution in SST regions of human limbs immediately after physical exercise in cold climate

Science.gov (United States)

Kumari, Babita; Adlakha, Neeru

2015-02-01

Thermoregulation is a complex mechanism regulating heat production within the body (chemical thermoregulation) and heat exchange between the body and the environment (physical thermoregulation) in such a way that the heat exchange is balanced and deep body temperatures are relatively stable. The external heat transfer mechanisms are radiation, conduction, convection and evaporation. The physical activity causes thermal stress and poses challenges for this thermoregulation. In this paper, a model has been developed to study temperature distribution in SST regions of human limbs immediately after physical exercise under cold climate. It is assumed that the subject is doing exercise initially and comes to rest at time t = 0. The human limb is assumed to be of cylindrical shape. The peripheral region of limb is divided into three natural components namely epidermis, dermis and subdermal tissues (SST). Appropriate boundary conditions have been framed based on the physical conditions of the problem. Finite difference has been employed for time, radial and angular variables. The numerical results have been used to obtain temperature profiles in the SST region immediately after continuous exercise for a two-dimensional unsteady state case. The results have been used to analyze the thermal stress in relation to light, moderate and vigorous intensity exercise.

Expanding the spectrum of human ganglionic eminence region anomalies on fetal magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Righini, Andrea; Parazzini, Cecilia; Izzo, Giana [Children' s Hospital ' ' V. Buzzi' ' , Department of Radiology and Neuroradiology, Milan (Italy); Cesaretti, Claudia [Children' s Hospital ' ' V. Buzzi' ' , Department of Radiology and Neuroradiology, Milan (Italy); Ospedale Maggiore Policlinico, Medical Genetics Unit, Fondazione I.R.C.C.S. Ca' Granda, Milan (Italy); Conte, Giorgio [Children' s Hospital ' ' V. Buzzi' ' , Department of Radiology and Neuroradiology, Milan (Italy); University of Milan, Department of Health Sciences, Milan (Italy); Frassoni, Carolina; Inverardi, Francesca [Fondazione I.R.C.C.S. Istituto Neurologico ' ' C. Besta' ' , Clinical Epileptology and Experimental Neurophysiology Unit, Milan (Italy); Bulfamante, Gaetano; Avagliano, Laura [San Paolo Hospital, Division of Human Pathology, Milan (Italy); Rustico, Mariangela [Children' s Hospital ' ' V. Buzzi' ' , Department of Obstetrics and Gynaecology, Prenatal Diagnosis, Milan (Italy)

2016-03-15

Ganglionic eminence (GE) is a transient fetal brain structure that harvests a significant amount of precursors of cortical GABA-ergic interneurons. Prenatal magnetic resonance (MR) imaging features of GE anomalies (i.e., cavitations) have already been reported associated with severe micro-lissencephaly. The purpose of this report was to illustrate the MR imaging features of GE anomalies in conditions other than severe micro-lissencephalies. Among all the fetuses submitted to prenatal MR imaging at our center from 2005 to 2014, we collected eight cases with GE anomalies and only limited associated brain anomalies. The median gestational age at the time of MR imaging was 21 weeks ranging from 19 to 29 weeks. Two senior pediatric neuroradiologists categorized the anomalies of the GE region in two groups: group one showing cavitation in the GE region and group two showing enlarged GE region. For each fetal case, associated cranial anomalies were also reported. Five out of the eight cases were included in group one and three in group two. Besides the GE region abnormality, all eight cases had additional intracranial anomalies, such as mild partial callosal agenesis, vermian hypoplasia and rotation, cerebellar hypoplasia, ventriculomegaly, enlarged subarachnoid spaces, molar tooth malformation. Ultrasound generally detected most of the associated intracranial anomalies, prompting the MR investigation; on the contrary in none of the cases, GE anomalies had been detected by ultrasound. Our observation expands the spectrum of human GE anomalies, demonstrating that these may take place also without associated severe micro-lissencephalies. (orig.)

Expanding the spectrum of human ganglionic eminence region anomalies on fetal magnetic resonance imaging

International Nuclear Information System (INIS)

Righini, Andrea; Parazzini, Cecilia; Izzo, Giana; Cesaretti, Claudia; Conte, Giorgio; Frassoni, Carolina; Inverardi, Francesca; Bulfamante, Gaetano; Avagliano, Laura; Rustico, Mariangela

2016-01-01

Ganglionic eminence (GE) is a transient fetal brain structure that harvests a significant amount of precursors of cortical GABA-ergic interneurons. Prenatal magnetic resonance (MR) imaging features of GE anomalies (i.e., cavitations) have already been reported associated with severe micro-lissencephaly. The purpose of this report was to illustrate the MR imaging features of GE anomalies in conditions other than severe micro-lissencephalies. Among all the fetuses submitted to prenatal MR imaging at our center from 2005 to 2014, we collected eight cases with GE anomalies and only limited associated brain anomalies. The median gestational age at the time of MR imaging was 21 weeks ranging from 19 to 29 weeks. Two senior pediatric neuroradiologists categorized the anomalies of the GE region in two groups: group one showing cavitation in the GE region and group two showing enlarged GE region. For each fetal case, associated cranial anomalies were also reported. Five out of the eight cases were included in group one and three in group two. Besides the GE region abnormality, all eight cases had additional intracranial anomalies, such as mild partial callosal agenesis, vermian hypoplasia and rotation, cerebellar hypoplasia, ventriculomegaly, enlarged subarachnoid spaces, molar tooth malformation. Ultrasound generally detected most of the associated intracranial anomalies, prompting the MR investigation; on the contrary in none of the cases, GE anomalies had been detected by ultrasound. Our observation expands the spectrum of human GE anomalies, demonstrating that these may take place also without associated severe micro-lissencephalies. (orig.)

Observed Local Soil Moisture-Atmosphere Feedbacks within the Context of Remote SST Anomalies: Lessons From Recent Droughts

Science.gov (United States)

Tawfik, A. B.; Dirmeyer, P.; Lawrence, D. M.

2015-12-01

The existence and possible transition from positive to negative soil moisture-atmosphere feedbacks is explored in this presentation using collocated flux tower measurements (Ameriflux) and atmospheric profiles from reanalysis. The focus is on the series of physical processes that lead to these local feedbacks connecting remote sea surface temperature changes (SST anomalies) to local soil moisture and boundary layer responses. Seasonal and Agricultural droughts are particularly useful test beds for examining these feedback processes because they are typically characterized by prolonged stretches of rain-free days followed by some termination condition. To quantify the full process-chain across these distinct spatial scales, complimentary information from several well-established land-atmosphere coupling metrics are used including, but not limited to, Mixing Diagram approaches, Soil Moisture Memory, and the Heated Condensation Framework. Preliminary analysis shows that there may be transitions from negative and positive soil moisture-atmosphere feedbacks as droughts develop. This is largely instigated by persistent atmospheric forcing that initially promotes increased surface latent heat flux, which limits boundary layer depth and dry air entrainment. However, if stagnant synoptic conditions continue eventually soil moisture is depleted to the point of shutting off surface latent heat flux producing deep boundary layers and increased dry air entrainment thus deepening drought stress. A package of standardized Fortran 90 modules called the Coupling Metrics Toolkit (CoMeT; https://github.com/abtawfik/coupling-metrics) used to calculate these land-atmosphere coupling metrics is also briefly presented.

Improved VIIRS and MODIS SST Imagery

Directory of Open Access Journals (Sweden)

Irina Gladkova

2016-01-01

Full Text Available Moderate Resolution Imaging Spectroradiometers (MODIS and Visible Infrared Imaging Radiometer Suite (VIIRS radiometers, flown onboard Terra/Aqua and Suomi National Polar-orbiting Partnership (S-NPP/Joint Polar Satellite System (JPSS satellites, are capable of providing superior sea surface temperature (SST imagery. However, the swath data of these multi-detector sensors are subject to several artifacts including bow-tie distortions and striping, and require special pre-processing steps. VIIRS additionally does two irreversible data reduction steps onboard: pixel aggregation (to reduce resolution changes across the swath and pixel deletion, which complicate both bow-tie correction and destriping. While destriping was addressed elsewhere, this paper describes an algorithm, adopted in the National Oceanic and Atmospheric Administration (NOAA Advanced Clear-Sky Processor for Oceans (ACSPO SST system, to minimize the bow-tie artifacts in the SST imagery and facilitate application of the pattern recognition algorithms for improved separation of ocean from cloud and mapping fine SST structure, especially in the dynamic, coastal and high-latitude regions of the ocean. The algorithm is based on a computationally fast re-sampling procedure that ensures a continuity of corresponding latitude and longitude arrays. Potentially, Level 1.5 products may be generated to benefit a wide range of MODIS and VIIRS users in land, ocean, cryosphere, and atmosphere remote sensing.

Impact of Air Temperature and SST Variability on Cholera Incidence in Southeastern Africa, 1971-2006

Science.gov (United States)

Paz, Shlomit

2010-05-01

The most important climatic parameter related to cholera outbreaks is the temperature, especially of the water bodies and the aquatic environment. This factor governs the survival and growth of V. cholerae, since it has a direct influence on its abundance in the environment, or alternatively, through its indirect influence on other aquatic organisms to which the pathogen is found to attach. Thus, the potential for cholera outbreaks may rise, parallel to the increase in ocean surface temperature. Indeed, recent studies indicate that global warming might create a favorable environment for V. cholerae and increase its incidence in vulnerable areas. Africa is vulnerable to climate variability. According to the recent IPCC report on Africa, the air temperature has indicated a significant warming trend since the 1960s. In recent years, most of the research into disease vectors in Africa related to climate variability has focused on malaria. The IPCC indicated that the need exists to examine the vulnerabilities and impacts of climatic factors on cholera in Africa. In light of this, the study uses a Poisson Regression Model to analyze the possible association between the cholera rates in southeastern Africa and the annual variability of air temperature and sea surface temperature (SST) at regional and hemispheric scales, for the period 1971-2006. Data description is as follows: Number of cholera cases per year in Uganda, Kenya, Rwanda, Burundi, Tanzania, Malawi, Zambia and Mozambique. Source: WHO Global Health Atlas - cholera. Seasonal and annual temperature time series: Regional scale: a) Air temperature for southeastern Africa (30° E-36° E, 5° S-17° S), source: NOAA NCEP-NCAR; b) Sea surface temperature, for the western Indian Ocean (0-20° S, 40° E-45° E), source: NOAA, Kaplan SST dataset. Hemispheric scale (for the whole Southern Hemisphere): a) Air temperature anomaly; b) Sea surface temperature anomaly. Source: CRU, University of East Anglia. The following

Characteristics of isostatic gravity anomaly in Sichuan-Yunnan region, China

Directory of Open Access Journals (Sweden)

Bingcheng Liu

2017-07-01

Full Text Available Sichuan-Yunnan region in China, a tectonic transition belt where earthquakes occurred frequently and intensely, has a distinct variation characteristic of gradient zone of Bouguer gravity anomaly (BGA. Many deep faults and epicenters of severe earthquake scatter along the BGA gradient zones. Here we apply two forward models (Airy model and Vening Meinesz model of isostatic gravity mechanisms (local versus regional in this region to calculated the isostatic gravity anomaly (IGA. Afterwards, the relationship between IGA and distribution of faults as well as seismicity is also illustrated. The IGA results show that the two models are similar and most parts of the study area are in an isostatic state. Most featured faults are distributed along the steep anomaly gradient zones; earthquakes tend to occur in the non-isostatic area and steep gradient belt of IGA. The distribution of root thickness based on regional mechanism can be associated with the main trend of BGA variation. The regional mechanism is more plausible and closer to the reality because of its relatively further consideration of the horizontal forces derived from adjacent particles in the crust. Then we analyze the effect of isostasy on the tectonic movements and find that the isostatic adjustment is not the main cause of the continuous uplift process of Longmenshan Mountain fault zone, which is due to the Indian-Eurasian continental collision.

A change in the relationship between tropical central Pacific SST variability and the extratropical atmosphere around 1990

International Nuclear Information System (INIS)

Yu, Jin-Yi; Kim, Seon Tae; Lu, Mong-Ming

2012-01-01

A newly released reanalysis dataset covering the period 1979–2009 is analyzed to show that the sea surface temperature (SST) variability in the tropical central Pacific is more closely related to the SST variability in the tropical eastern Pacific before 1990 but more closely related to sea level pressure (SLP) variations associated with the North Pacific Oscillation (NPO) after 1990. Only during the period after 1990 can the NPO excite large SST variability in the tropical central Pacific. Related to this change, El Niño Southern Oscillation (ENSO) SST anomalies tend to spread from the eastern to central tropical Pacific before 1990 in a pattern resembling that associated with the Eastern Pacific (EP) type of ENSO, but are more closely connected to SST variability in the subtropical north Pacific after 1990 with a pattern resembling that of the Central Pacific (CP) type of ENSO. This study concludes that the increased influence of the NPO on the tropical Pacific is a likely reason for the increasing occurrence of the CP type of ENSO since 1990. An analysis of the mean atmospheric circulation during these two periods suggests that the increased NPO influence is associated with a strengthening Hadley circulation after 1990. (letter)

Trends in the number of extreme hot SST days along the Canary Upwelling System due to the influence of upwelling

Directory of Open Access Journals (Sweden)

Xurxo Costoya

2014-07-01

Full Text Available Trends in the number of extreme hot days (days with SST anomalies higher than the 95% percentile were analyzed along the Canary Upwelling Ecosystem (CUE over the period 1982- 2012 by means of SST data retrieved from NOAA OI1/4 Degree. The analysis will focus on the Atlantic Iberian sector and the Moroccan sub- region where upwelling is seasonal (spring and summer are permanent, respectively. Trends were analyzed both near coast and at the adjacent ocean where the increase in the number of extreme hot days is higher. Changes are clear at annual scale with an increment of 9.8±0.3 (9.7±0.1 days dec-1 near coast and 11.6±0.2 (13.5±0.1 days dec-1 at the ocean in the Atlantic Iberian sector (Moroccan sub-region. The differences between near shore and ocean trends are especially patent for the months under intense upwelling conditions. During that upwelling season the highest differences in the excess of extreme hot days between coastal and ocean locations (Δn(#days dec-1 occur at those regions where coastal upwelling increase is high. Actually, Δn and upwelling trends have shown to be significantly correlated in both areas, R=0.88 (p<0.01 at the Atlantic Iberian sector and R=0.67 (p<0.01 at the Moroccan sub-region.

Regional seasonal warming anomalies and land-surface feedbacks

Science.gov (United States)

Coffel, E.; Horton, R. M.

2017-12-01

Significant seasonal variations in warming are projected in some regions, especially central Europe, the southeastern U.S., and central South America. Europe in particular may experience up to 2°C more warming during June, July, and August than in the annual mean, enhancing the risk of extreme summertime heat. Previous research has shown that heat waves in Europe and other regions are tied to seasonal soil moisture variations, and that in general land-surface feedbacks have a strong effect on seasonal temperature anomalies. In this study, we show that the seasonal anomalies in warming are also due in part to land-surface feedbacks. We find that in regions with amplified warming during the hot season, surface soil moisture levels generally decline and Bowen ratios increase as a result of a preferential partitioning of incoming energy into sensible vs. latent. The CMIP5 model suite shows significant variability in the strength of land-atmosphere coupling and in projections of future precipitation and soil moisture. Due to the dependence of seasonal warming on land-surface processes, these inter-model variations influence the projected summertime warming amplification and contribute to the uncertainty in projections of future extreme heat.

Measurements of additional X-ray flux in South Atlantic magnetic anomaly region

International Nuclear Information System (INIS)

Martin, I.M.

1968-01-01

The purpose of this study is the calculation of the additional X-ray flux (20 - 150 KeV), produced by electron precipitation in the South Atlantic anomaly region. The kind of detector and the technique employed in the observations of this flux, utilizing stratospheric balloons as a means of transport of the payload across the anomaly region, are described. The results of two balloon launchins in Sao Jose dos Campos in July 1968, with the expected flux, are compared. (author) [pt

ANALYSIS OF SST IMAGES BY WEIGHTED ENSEMBLE TRANSFORM KALMAN FILTER

OpenAIRE

Sai , Gorthi; Beyou , Sébastien; Memin , Etienne

2011-01-01

International audience; This paper presents a novel, efficient scheme for the analysis of Sea Surface Temperature (SST) ocean images. We consider the estimation of the velocity fields and vorticity values from a sequence of oceanic images. The contribution of this paper lies in proposing a novel, robust and simple approach based onWeighted Ensemble Transform Kalman filter (WETKF) data assimilation technique for the analysis of real SST images, that may contain coast regions or large areas of ...

Vessel eddy current characteristics in SST-1 tokamak

Energy Technology Data Exchange (ETDEWEB)

Jana, Subrata; Pradhan, Subrata, E-mail: pradhan@ipr.res.in; Dhongde, Jasraj; Masand, Harish

2016-11-15

Highlights: • Eddy current distribution in the SST-1 vacuum vessel. • Circuit model analysis of eddy current. • A comparison of the field lines with and without the plasma column in identical conditions. • The influence of eddy current in magnetic NULL dynamics. - Abstract: Eddy current distribution in the vacuum vessel of the Steady state superconducting (SST-1) tokamak has been determined from the experimental data obtained using an array of internal voltage loops (flux loop) installed inside the vacuum vessel. A simple circuit model has been employed. The model takes into account the geometric and constructional features of SST-1 vacuum vessel. SST-1 vacuum vessel is a modified ‘D’ shaped vessel having major axis of 1.285 m and minor axis of 0.81 m and has been manufactured from non-magnetic stainless steel. The Plasma facing components installed inside the vacuum vessel are graphite blocks mounted on Copper Chromium Zirconium (CuCrZr) heat sink plates on inconel supports. During discharge of the central solenoid, eddy currents get generated in the vacuum vessel and passive supports on it. These eddy currents influence the early magnetic NULL dynamics and plasma break-down and start-up characteristics. The computed results obtained from the model have been benchmarked against experimental data obtained in large number of SST-1 plasma shots. The results are in good agreement. Once bench marked, the calculated eddy current based on flux loop signal and circuit equation model has been extended to the reconstruction of the overall B- field contours of SST-1 tokamak in the vessel region. A comparison of the field lines with and without the plasma column in identical conditions of the central solenoid and equilibrium field profiles has also been done with an aim to quantify the diagnostics responses in vacuum shots.

The Relationships between Tropical Pacific and Atlantic SST and Northeast Brazil Monthly Precipitation.

Science.gov (United States)

Bertacchi Uvo, Cintia; Repelli, Carlos A.; Zebiak, Stephen E.; Kushnir, Yochanan

1998-04-01

The monthly patterns of northeast Brazil (NEB) precipitation are analyzed in relation to sea surface temperature (SST) in the tropical Pacific and Atlantic Oceans, using singular value decomposition. It is found that the relationships between precipitation and SST in both basins vary considerably throughout the rainy season (February-May). In January, equatorial Pacific SST is weakly correlated with precipitation in small areas of southern NEB, but Atlantic SST shows no significant correlation with regional precipitation. In February, Pacific SST is not well related to precipitation, but south equatorial Atlantic SST is positively correlated with precipitation over the northern Nordeste, the latter most likely reflecting an anomalously early (or late) southward migration of the ITCZ precipitation zone. During March, equatorial Pacific SST is negatively correlated with Nordeste precipitation, but no consistent relationship between precipitation and Atlantic SST is found. Atlantic SST-precipitation correlations for April and May are the strongest found among all months or either ocean. Precipitation in the Nordeste is positively correlated with SST in the south tropical Atlantic and negatively correlated with SST in the north tropical Atlantic. These relationships are strong enough to determine the structure of the seasonal mean SST-precipitation correlations, even though the corresponding patterns for the earlier months of the season are quite different. Pacific SST-precipitation correlations for April and May are similar to those for March. Extreme wet (dry) years for the Nordeste occur when both Pacific and Atlantic SST patterns for April and May occur simultaneously. A separate analysis reinforces previous findings in showing that SST in the tropical Pacific and the northern tropical Atlantic are positively correlated and that tropical Pacific-south Atlantic correlations are negligible.Time-lagged analyses show the potential for forecasting either seasonal mean

Tropical Ocean Evaporation/SST Sensitivity and It's Link to Water and Energy Budget Variations During ENSO

Science.gov (United States)

Robertson, Franklin R.; Marshall, Susan; Oglesby, Robert; Roads, John; Sohn, Byung-Ju; Arnold, James E. (Technical Monitor)

2001-01-01

The continuing debate over feedback mechanisms governing tropical sea surface temperatures (SSTs) and tropical climate in general has highlighted the diversity of potential checks and balances within the climate system. Competing feedbacks due to changes in surface evaporation, water vapor, and cloud long- and shortwave radiative properties each may serve critical roles in stabilizing or destabilizing the climate system. It is also intriguing that even those climate variations having origins internal to the climate system - changes in ocean heat transport for example, apparently require complementary equilibrating effects by changes in atmospheric energy fluxes. Perhaps the best observational evidence of this is the relatively invariant nature of tropically averaged net radiation exiting the top-of-atmosphere (TOA) as measured by broadband satellite sensors over the past two decades. Thus, analyzing how these feedback mechanisms are operating within the context of current interannual variability may offer considerable insight for anticipating future climate change. In this paper we focus primarily on interannual variations of ocean evaporative fluxes and their significance for coupled water and energy cycles within the tropical climate system. In particular, we use both the da Silva estimates of surface fluxes (based on the Comprehensive Ocean Atmosphere Data Set, COADS) and numerical simulations from several global climate models to examine evaporation sensitivity to perturbations in SST associated with warm and cold ENSO events. The specific questions we address are as follows: (1) What recurring patterns of surface wind and humidity anomalies are present during ENSO and how do they combine to yield systematic evaporation anomalies?, (2) What is the resulting tropical ocean mean evaporation-SST sensitivity associated with this climate perturbation?, and (3) What role does this evaporation play in tropical heat and water balance over tropical oceanic regions? We

Southern Indian Ocean SST as a modulator for the progression of Indian summer monsoon

Science.gov (United States)

Shahi, Namendra Kumar; Rai, Shailendra; Mishra, Nishant

2018-01-01

This study explores the possibility of southern Indian Ocean (SIO) sea surface temperature (SST) as a modulator for the early phase of Indian summer monsoon and its possible physical mechanism. A dipole-like structure is obtained from the empirical orthogonal function (EOF) analysis which is similar to an Indian Ocean subtropical dipole (IOSD) found earlier. A subtropical dipole index (SDI) is defined based on the SST anomaly over the positive and negative poles. The regression map of rainfall over India in the month of June corresponding to the SDI during 1983-2013 shows negative patterns along the Western Ghats and Central India. However, the regression pattern is insignificant during 1952-1982. The multiple linear regression models and partial correlation analysis also indicate that the SDI acts as a dominant factor to influence the rainfall over India in the month of June during 1983-2013. The similar result is also obtained with the help of composite rainfall over the land points of India in the month of June for positive (negative) SDI events. It is also observed that the positive (negative) SDI delays (early) the onset dates of Indian monsoon over Kerala during the time domain of our study. The study is further extended to identify the physical mechanism of this impact, and it is found that the heating (cooling) in the region covering SDI changes the circulation pattern in the SIO and hence impacts the progression of monsoon in India.

SST algorithms in ACSPO reanalysis of AVHRR GAC data from 2002-2013

Science.gov (United States)

Petrenko, B.; Ignatov, A.; Kihai, Y.; Zhou, X.; Stroup, J.

2014-05-01

In response to a request from the NOAA Coral Reef Watch Program, NOAA SST Team initiated reprocessing of 4 km resolution GAC data from AVHRRs flown onboard NOAA and MetOp satellites. The objective is to create a longterm Level 2 Advanced Clear-Sky Processor for Oceans (ACSPO) SST product, consistent with NOAA operations. ACSPO-Reanalysis (RAN) is used as input in the NOAA geo-polar blended Level 4 SST and potentially other Level 4 SST products. In the first stage of reprocessing (reanalysis 1, or RAN1), data from NOAA-15, -16, -17, -18, -19, and Metop-A and -B, from 2002-present have been processed with ACSPO v2.20, and matched up with quality controlled in situ data from in situ Quality Monitor (iQuam) version 1. The ~12 years time series of matchups were used to develop and explore the SST retrieval algorithms, with emphasis on minimizing spatial biases in retrieved SSTs, close reproduction of the magnitudes of true SST variations, and maximizing temporal, spatial and inter-platform stability of retrieval metrics. Two types of SST algorithms were considered: conventional SST regressions, and recently developed incremental regressions. The conventional equations were adopted in the EUMETSAT OSI-SAF formulation, which, according to our previous analyses, provide relatively small regional biases and well-balanced combination of precision and sensitivity, in its class. Incremental regression equations were specifically elaborated to automatically correct for model minus observation biases, always present when RTM simulations are employed. Improved temporal stability was achieved by recalculation of SST coefficients from matchups on a daily basis, with a +/-45 day window around the current date. This presentation describes the candidate SST algorithms considered for the next round of ACSPO reanalysis, RAN2.

Global 1-km Sea Surface Temperature (G1SST)

Data.gov (United States)

National Aeronautics and Space Administration — JPL OurOcean Portal: A daily, global Sea Surface Temperature (SST) data set is produced at 1-km (also known as ultra-high resolution) by the JPL ROMS (Regional Ocean...

Concurrent Sr/Ca Ratios and Bomb Test 14C Records from a Porites evermanni Colony on Kure Atoll: SST, Climate Change, Ocean Circulation and Management Applications

Science.gov (United States)

Covarrubias, S.; Potts, D.; Siciliano, D.; Andrews, A.; Franks, R.

2013-12-01

Coral reefs near their latitudinal and ecological limits may be affected disproportionately by global climate changes, especially by changing sea surface temperatures (SST's). One such reef is Kure Atoll, the northernmost reef in the Hawaiian chain. Kure Atoll experiences dramatic temperature and seasonal differences throughout the year. Tracking these fluctuations is important for understanding recent physical forces affecting coral growth in such marginal reefs, and for predicting likely responses to future climate and oceanic changes. We used Sr/Ca ratios of a 50cm Porites evermanni coral core collected in Kure (September 2002) as a SST proxy for reconstructing a temperature timescale spanning the length of the core (~62 years). After cutting a 5 mm thick slab through the center growth axis and X-raying it to identify annual density banding, we extracted 4 equally-spaced samples from each annual increment to quantify, seasonal, inter-annual, and decadal SST patterns. We measured Sr and Ca concentrations by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). We then converted Sr/Ca ratios (mmol/mol) to SST using published equations, and calibrated the more recent SST estimates against satellite-based SST imagery and instrumental records from Midway Atoll (ca. 90 km to SE). We coupled the ICP-OES data with Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) scans along the core to provide higher temporal resolution for interpreting intra-seasonal and inter-seasonal trends. Higher resolution of temperature dating can help us interpret strong inter-seasonal changes not readily seen with low resolution measurements, giving us the ability to track temperature anomalies at interannual and decadal timescales, such as El Niño/Southern Oscillation or La Niña/North Pacific Decadal Oscillation. Further, the SST signature from the Sr/Ca analyses are being used in conjunction with bomb radiocarbon signals in order to establish a complete

Correlation and SVD Analysis of Anomalous Spring Precipitation in Northwest China and Sea Surface Temperature in Key Region in Recent 50 Years

Institute of Scientific and Technical Information of China (English)

无

2011-01-01

[Objective] The aim was to study the relationship between spring precipitation anomaly in Northwest China and sea surface temperature anomaly (SSTA) in Key region in recent 50 years. [Method] Based on monthly average precipitation in Northwest China and global monthly sea surface temperature (SST) grid data, the effects of SSTA in equatorial central and eastern Pacific on spring precipitation in Northwest China were discussed by means of correlation and SVD analysis. [Result] For spring precipitation in Nor...

About the nature of regional thermal anomaly in the Semipalatinsk Test Site region revealed basing on remote space sensing data

International Nuclear Information System (INIS)

Melent'ev, M.I.; Velikanov, A.E.

2003-01-01

A thermal anomaly, (more than 20,000 sq. km) discovered in the Semipalatinsk Test Site region in the pictures from space, is observed every year on certain days mainly in winter-spring season. Appearance of the thermal anomaly often coincides with days of intensive fall of atmospheric precipitation and possible thawing of snow cover together with decreasing of ozone concentration in atmosphere. The explanation of thermal anomaly in the Semipalatinsk Test Site region due to nuclear reaction caused by the energy of radionuclide radioactive decay deposited in a soil layer after ground and air nuclear explosions and radiolysis processes in soil solutions is given in this article. (author)

Impact of the Gulf of California SST on simulating precipitation and crop productivity in the Southwestern United States

Science.gov (United States)

Kim, S.; Kim, J.; Prasad, A. K.; Stack, D. H.; El-Askary, H. M.; Kafatos, M.

2012-12-01

Like other ecosystems, agricultural productivity is substantially affected by climate factors. Therefore, accurate climatic data (i.e. precipitation, temperature, and radiation) is crucial to simulating crop yields. In order to understand and anticipate climate change and its impacts on agricultural productivity in the Southwestern United States, the WRF regional climate model (RCM) and the Agricultural Production Systems sIMulator (APSIM) were employed for simulating crop production. 19 years of WRF RCM output show that there is a strong dry bias during the warm season, especially in Arizona. Consequently, the APSIM crop model indicates very low crop yields in this region. We suspect that the coarse resolution of reanalysis data could not resolve the relatively warm Sea Surface Temperature (SST) in the Gulf of California (GC), causing the SST to be up to 10 degrees lower than the climatology. In the Southwestern United States, a significant amount of precipitation is associated with North American Monsoon (NAM). During the monsoon season, the low-level moisture is advected to the Southwestern United States via the GC, which is known to be the dominant moisture source. Thus, high-resolution SST data in the GC is required for RCM simulations to accurately represent a reasonable amount of precipitation in the region, allowing reliable evaluation of the impacts on regional ecosystems.and evaluate impacts on regional ecosystems. To evaluate the influence of SST on agriculture in the Southwestern U.S., two sets of numerical simulations were constructed: a control, using unresolved SST of GC, and daily updated SST data from the MODIS satellite sensor. The meteorological drivers from each of the 6 year RCM runs were provided as input to the APSIM model to determine the crop yield. Analyses of the simulated crop production, and the interannual variation of the meteorological drivers, demonstrate the influence of SST on crop yields in the Southwestern United States.

Immunohistochemical detection of somatostatin receptor subtypes sst1 and sst2A in human somatostatin receptor positive tumors

NARCIS (Netherlands)

L.J. Hofland (Leo); Q. Liu; P.M. van Koetsveld (Peter); J. Zuijderwijk; F. van der Ham (Frieda); R.R. de Krijger (Ronald); A. Schonbrunn; S.W.J. Lamberts (Steven)

1999-01-01

textabstractAlthough in situ hybridization has been used to examine the distribution of messenger RNA for somatostatin receptor subtypes (sst) in human tumors, the cellular localization of sst1 and sst2A receptors has not been reported. In this study, we describe the

Impact assessment of El Nino and La Nina episodes on local/regional monsoon rainfall in India

International Nuclear Information System (INIS)

Singh, Sureuder; Rao, V.U.M.; Shigh, Diwan

2002-08-01

Large scale atmospheric circulation's and climatic anomalies have been shown to have a significant impact on seasonal weather over many parts of the world. In the present paper an attempt has been made to examine regional monsoon dynamics in relation with El Nino and La Nina episodes. The investigation was earned out for the meteorological sub- division's comprising the areas of Haryana, Delhi and Chandigarh in India. The monthly monsoon rainfall data of different locations in the region and corresponding data on El Nino and La Nina episodes for the period of 30 years (1970-99) were used for this investigation. During the El Nino episodes, various locations experienced excess rainfall in monsoon ranged between 11 and 22 percent. Under the influence of La Nina episodes, the probability of excess monsoon rainfall at different locations in the sub-division ranged between 13 and 25 percent. However, many locations viz., Hisar, Bhiwani, Gurgaon, Delhi and Chandigarh received deficient monsoon rainfall which was contrary to the global belief of the association between SST anomalies and rainfall distribution. No significant association was observed between El Nino and La Nina and monsoon rainfall at different locations in the entire sub-division. However, there was a strong relationship between these SST anomalies and all India monsoon rainfall over the period under study (1970-99). (author)

Operation of SST-1 TF power supply during SST-1 campaigns

International Nuclear Information System (INIS)

Sharma, Dinesh Kumar; Vora, Murtuza M.; Ojha, Amit; Singh, Akhilesh Kumar; Bhavsar, Chirag

2015-01-01

Highlights: • SST-1 TF power supply is 12 pulse SCR converter circuit. • TF power supply protection, measurement and control scheme are explained. • Quench, emergency and normal shot process is explained and results of SST-1 campaigns are shown. • Dynamic control of TF current. • The paper shows the results of last ten SST-1 campaigns. - Abstract: SST-1 TF power supply provides the direct current for the required magnetic field of TF coil. TF power supply includes transformer, 12-pulse converter, bus bar, water-cooled cable, protection and measuring equipments, and isolator, VME DAC system and GUI software. TF power supply is operated through GUI software built in TCL/Tk. VME DAC system monitors the parameters, provides On/Off commands, voltage and current references and initiates predefined reference to emergency shutdown. The emergency shutdown is hardwired to TF power supply from central control. During quench power supply converter opens DCCB and dump resistor is connected in the circuit and VME DAC system acquires bus bar voltage, dump voltage and dump current. Operation of TF power supply also requires monitoring of SCR and transformer temperature and water flow rate of water-cooled cable during high current long pulse shot. Before start up of TF power supply a quench simulation is performed to check the readiness of protection. This paper describes pre startup operation, normal shot operation, emergency and quench process, dynamic control and complete shutdown operation of TF power supply.

Operation of SST-1 TF power supply during SST-1 campaigns

Energy Technology Data Exchange (ETDEWEB)

Sharma, Dinesh Kumar, E-mail: dinesh@ipr.res.in; Vora, Murtuza M.; Ojha, Amit; Singh, Akhilesh Kumar; Bhavsar, Chirag

2015-10-15

Highlights: • SST-1 TF power supply is 12 pulse SCR converter circuit. • TF power supply protection, measurement and control scheme are explained. • Quench, emergency and normal shot process is explained and results of SST-1 campaigns are shown. • Dynamic control of TF current. • The paper shows the results of last ten SST-1 campaigns. - Abstract: SST-1 TF power supply provides the direct current for the required magnetic field of TF coil. TF power supply includes transformer, 12-pulse converter, bus bar, water-cooled cable, protection and measuring equipments, and isolator, VME DAC system and GUI software. TF power supply is operated through GUI software built in TCL/Tk. VME DAC system monitors the parameters, provides On/Off commands, voltage and current references and initiates predefined reference to emergency shutdown. The emergency shutdown is hardwired to TF power supply from central control. During quench power supply converter opens DCCB and dump resistor is connected in the circuit and VME DAC system acquires bus bar voltage, dump voltage and dump current. Operation of TF power supply also requires monitoring of SCR and transformer temperature and water flow rate of water-cooled cable during high current long pulse shot. Before start up of TF power supply a quench simulation is performed to check the readiness of protection. This paper describes pre startup operation, normal shot operation, emergency and quench process, dynamic control and complete shutdown operation of TF power supply.

Climate Prediction Center (CPC)Area-averaged 850-hPa Western Pacific Trade Wind Anomalies

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This is one of the CPC?s Monthly Atmospheric and SST Indices. It is the 850-hPa trade wind anomalies averaged over the area 5oN ? 5oS, 135oE-180o (western equatorial...

Climate Prediction Center (CPC)Area-averaged 850-hPa Eastern Pacific Trade Wind Anomalies

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This is one of the CPC?s Monthly Atmospheric and SST Indices. It is the 850-hPa trade wind anomalies averaged over the area 5oN ? 5oS, 135oW-120oW (eastern...

Climate Prediction Center (CPC)Area-averaged 850-hPa Central Pacific Trade Wind Anomalies

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This is one of the CPC?s Monthly Atmospheric and SST Indices. It is the 850-hPa trade wind anomalies averaged over the area 5oN ? 5oS, 175oW-140oW (central...

Initial results in SST-1 after up-gradation

Science.gov (United States)

Pradhan, S.; Khan, Z.; Tanna, V. L.; Prasad, U.; Paravastu, Y.; Raval, D. C.; Masand, H.; Kumar, Aveg; Dhongde, J. R.; Jana, S.; Kakati, B.; Patel, K. B.; Bhandarkar, M. K.; Shukla, B. K.; Ghosh, D.; Patel, H. S.; Parekh, T. J.; Mansuri, I. A.; Dhanani, K. R.; Varadharajulu, A.; Khristi, Y. S.; Biswas, P.; Gupta, C. N.; George, S.; Semwal, P.; Sharma, D. K.; Gulati, H. K.; Mahajan, K.; Praghi, B. R.; Banaudha, M.; Makwana, A. R.; Chudasma, H. H.; Kumar, M.; Manchanda, R.; Joisa, Y. S.; Asudani, K.; Pandya, S. N.; Pathak, S. K.; Banerjee, S.; Patel, P. J.; Santra, P.; Pathan, F. S.; Chauhan, P. K.; Khan, M. S.; Thankey, P. L.; Prakash, A.; Panchal, P. N.; Panchal, R. N.; Patel, R. J.; Mahsuria, G. I.; Sonara, D. P.; Patel, K. M.; Jayaswal, S. P.; Sharma, M.; Patel, J. C.; Varmora, P.; Srikanth, G. L. N.; Christian, D. R.; Garg, A.; Bairagi, N.; Babu, G. R.; Panchal, A. G.; Vora, M. M.; Singh, A. K.; Sharma, R.; Nimavat, H. D.; Shah, P. R.; Purwar, G.; Raval, T. Y.; Sharma, A. L.; Ojha, A.; Kumar, S.; Ramaiya, N. K.; Siju, V.; Gopalakrishna, M. V.; Kumar, A.; Sharma, P. K.; Atrey, P. K.; Kulkarni, SV; Ambulkar, K. K.; Parmar, P. R.; Thakur, A. L.; Raval, J. V.; Purohit, S.; Mishra, P. K.; Adhiya, A. N.; Nagora, U. C.; Thomas, J.; Chaudhari, V. K.; Patel, K. G.; Dalakoti, S.; Virani, C. G.; Gupta, S.; Kumar, Ajay; Chaudhari, B.; Kaur, R.; Srinivasan, R.; Raju, D.; Kanabar, D. H.; Jha, R.; Das, A.; Bora, D.

2017-04-01

SST-1 Tokamak has recently completed the 1st phase of up-gradation with successful installation and integration of all its First Wall components. The First Wall of SST-1 comprises of ∼ 3800 high heat flux compatible graphite tiles being assembled and installed on 132 CuCrZr heat sink back plates engraved with ∼ 4 km of leak tight baking and cooling channels in five major sub groups equipped with ∼ 400 sensors and weighing ∼ 6000 kg in total in thirteen isolated galvanic and six isolated hydraulic circuits. The phase-1 up-gradation spectrum also includes addition of Supersonic Molecular Beam Injection (SMBI) both on the in-board and out-board side, installation of fast reciprocating probes, adding some edge plasma probe diagnostics in the SOL region, installation and integration of segmented and up-down symmetric radial coils aiding/controlling plasma rotations, introduction of plasma position feedback and density controls etc. Post phase-I up-gradation spanning from Nov 2014 till June 2016, initial plasma experiments in up-graded SST-1 have begun since Aug 2016 after a brief engineering validation period in SST-1. The first experiments in SST-1 have revealed interesting aspects on the ‘eddy currents in the First Wall support structures’ influencing the ‘magnetic Null evolution dynamics’ and the subsequent plasma start-up characteristics after the ECH pre-ionization, the influence of the first walls on the ‘field errors’ and the resulting locked modes observed, the magnetic index influencing the evolution of the equilibrium of the plasma column, low density supra-thermal electron induced discharges and normal ohmic discharges etc. Presently; repeatable ohmic discharges regimes in SST-1 having plasma currents in excess of 65 KA (qa ∼ 3.8, BT = 1.5 T) with a current ramp rates ∼ 1.2 MA/s over a duration of ∼ 300 ms with line averaged densities ∼ 0.8 × 1019 and temperatures ∼ 200 eV with copious MHD signatures have been experimentally

Variations of Sea Surface Temperature, Wind Stress, and Rainfall over the Tropical Atlantic and South America.

Science.gov (United States)

Nobre, Paulo; Srukla, J.

1996-10-01

Empirical orthogonal functions (E0Fs) and composite analyses are used to investigate the development of sea surface temperature (SST) anomaly patterns over the tropical Atlantic. The evolution of large-scale rainfall anomaly patterns over the equatorial Atlantic and South America are also investigated. 71e EOF analyses revealed that a pattern of anomalous SST and wind stress asymmetric relative to the equator is the dominant mode of interannual and longer variability over the tropical Atlantic. The most important findings of this study are as follows.Atmospheric circulation anomalies precede the development of basinwide anomalous SST patterns over the tropical Atlantic. Anomalous SST originate off the African coast simultaneously with atmospheric circulation anomalies and expand westward afterward. The time lag between wind stress relaxation (strengthening) and maximum SST warming (cooling) is about two months.Anomalous atmospheric circulation patterns over northern tropical Atlantic are phase locked to the seasonal cycle. Composite fields of SLP and wind stress over northern tropical Atlantic can be distinguished from random only within a few months preceding the March-May (MAM) season. Observational evidence is presented to show that the El Niño-Southern Oscillation phenomenon in the Pacific influences atmospheric circulation and SST anomalies over northern tropical Atlantic through atmospheric teleconnection patterns into higher latitudes of the Northern Hemisphere.The well-known droughts over northeastern Brazil (Nordeste) are a local manifestation of a much larger-scale rainfall anomaly pattern encompassing the whole equatorial Atlantic and Amazon region. Negative rainfall anomalies to the south of the equator during MAM, which is the rainy season for the Nordeste region, are related to an early withdrawal of the intertropical convergence zone toward the warm SST anomalies over the northern tropical Atlantic. Also, it is shown that precipitation anomalies

Gas Fuelling System for SST-1Tokamak

Science.gov (United States)

Dhanani, Kalpesh; Raval, D. C.; Khan, Ziauddin; Semwal, Pratibha; George, Siju; Paravastu, Yuvakiran; Thankey, Prashant; Khan, M. S.; Pradhan, Subrata

2017-04-01

SST-1 Tokamak, the first Indian Steady-state Superconducting experimental device is at present under operation in the Institute for Plasma Research. For plasma break down & initiation, piezoelectric valve based gas feed system is implemented as a primary requirement due to its precise control, easy handling, low construction and maintenance cost and its flexibility in the selection of the working gas. Hydrogen gas feeding with piezoelectric valve is used in the SST-1 plasma experiments. The piezoelectric valves used in SST-1 are remotely driven by a PXI based platform and are calibrated before each SST-1 plasma operation with precise control. This paper will present the technical development and the results of the gas fuelling system of SST-1.

Seasonal predictions of equatorial Atlantic SST in a low-resolution CGCM with surface heat flux correction

Science.gov (United States)

Dippe, Tina; Greatbatch, Richard; Ding, Hui

2016-04-01

The dominant mode of interannual variability in tropical Atlantic sea surface temperatures (SSTs) is the Atlantic Niño or Zonal Mode. Akin to the El Niño-Southern Oscillation in the Pacific sector, it is able to impact the climate both of the adjacent equatorial African continent and remote regions. Due to heavy biases in the mean state climate of the equatorial-to-subtropical Atlantic, however, most state-of-the-art coupled global climate models (CGCMs) are unable to realistically simulate equatorial Atlantic variability. In this study, the Kiel Climate Model (KCM) is used to investigate the impact of a simple bias alleviation technique on the predictability of equatorial Atlantic SSTs. Two sets of seasonal forecasting experiments are performed: An experiment using the standard KCM (STD), and an experiment with additional surface heat flux correction (FLX) that efficiently removes the SST bias from simulations. Initial conditions for both experiments are generated by the KCM run in partially coupled mode, a simple assimilation technique that forces the KCM with observed wind stress anomalies and preserves SST as a fully prognostic variable. Seasonal predictions for both sets of experiments are run four times yearly for 1981-2012. Results: Heat flux correction substantially improves the simulated variability in the initialization runs for boreal summer and fall (June-October). In boreal spring (March-May), however, neither the initialization runs of the STD or FLX-experiments are able to capture the observed variability. FLX-predictions show no consistent enhancement of skill relative to the predictions of the STD experiment over the course of the year. The skill of persistence forecasts is hardly beat by either of the two experiments in any season, limiting the usefulness of the few forecasts that show significant skill. However, FLX-forecasts initialized in May recover skill in July and August, the peak season of the Atlantic Niño (anomaly correlation

Gas fueling system for SST-1

International Nuclear Information System (INIS)

Dhanani, Kalpeshkumar R.; Khan, Ziauddin; Raval, Dilip; Semwal, Pratibha; George, Siju; Paravastu, Yuvakiran; Thankey, Prashant; Khan, Mohammad Shoaib; Pradhan, Subrata

2015-01-01

SST-1 Tokamak, the first Indian Steady-state Superconducting experimental device is at present under operation in Institute for Plasma Research. For plasma break down and initiation, the piezoelectric valve based gas feed system is implemented as primary requirement due to its precise control, easy handling, low costs for both construction and maintenance and its flexibility in working gas selection. The main functions of SST-1 gas feed system are to feed the required amount of ultrahigh purity hydrogen gas for specified period into the vessel during plasma operation and ultrahigh helium gas for glow discharge cleaning. In addition to these facilities, the gas feed system is used to feed a mixture gas of hydrogen and helium as well as other gases like nitrogen and Argon during divertor cooling etc. The piezoelectric valves used in SST-1 are remotely driven by a PXI based platform and are calibrated before the plasma operation during each SST-1 plasma operation with precise control. This paper will present the technical development and the results of gas fueling in SST-1. (author)

Response of the Arabian Sea to global warming and associated regional climate shift

Digital Repository Service at National Institute of Oceanography (India)

PrasannaKumar, S.; Roshin, R.P.; Narvekar, J.; DineshKumar, P.K.; Vivekanandan, E.

-Atmosphere Data Set (ICOADS) (Woodruff et al., 2005) (http://www.cdc.noaa.gov/cdc/data.coads.1deg.html), (2) NOAA SST data (Reynolds et al., 2002) and (3) Kaplan SST data (Kaplan et al., 1998), both provided by the NOAA/OAR/ERSL PSD, Boulder, Colorado, USA... from their website http://www.cdc.noaa.gov/in (Reynolds et al., 2002). From the monthly mean SST annual mean SST anomaly was computed for further analysis. The strong El Nino years (1972-73, 1982-83, 1991-92 and 1997- 98) (see http...

Detection of a weak meddy-like anomaly from high-resolution satellite SST maps

Directory of Open Access Journals (Sweden)

Mikhail Emelianov

2012-09-01

Full Text Available Despite the considerable impact of meddies on climate through the long-distance transport of properties, a consistent observation of meddy generation and propagation in the ocean is rather elusive. Meddies propagate at about 1000 m below the ocean surface, so satellite sensors are not able to detect them directly and finding them in the open ocean is more fortuitous than intentional. However, a consistent census of meddies and their paths is required in order to gain knowledge about their role in transporting properties such as heat and salt. In this paper we propose a new methodology for processing high-resolution sea surface temperature maps in order to detect meddy-like anomalies in the open ocean on a near-real-time basis. We present an example of detection, involving an atypical meddy-like anomaly that was confirmed as such by in situ measurements.

Major congenital anomalies in a Danish region

DEFF Research Database (Denmark)

Garne, Ester; Hansen, Anne Vinkel; Birkelund, Anne Sofie

2014-01-01

INTRODUCTION: This study describes the prevalence of congenital anomalies and changes over time in birth outcome, mortality and chronic maternal diseases. MATERIAL AND METHODS: This study was based on population data from the EUROCAT registry covering the Funen County, Denmark, 1995...... mortality decreased significantly over time for cases with major congenital anomalies (p congenital anomaly cases, 8% had a registration of one of these chronic maternal diseases......: diabetes, epilepsy, mental disorder, thyroid disease, asthma, or inflammatory bowel disease. Medication for these conditions accounted for 46% of maternal drug use. CONCLUSION: Maternal morbidity and use of potentially teratogenic medication have increased among congenital anomaly cases. Foetal and infant...

Decadal climate predictability in the southern Indian Ocean captured by SINTEX-F using a simple SST-nudging scheme.

Science.gov (United States)

Morioka, Yushi; Doi, Takeshi; Behera, Swadhin K

2018-01-26

Decadal climate variability in the southern Indian Ocean has great influences on southern African climate through modulation of atmospheric circulation. Although many efforts have been made to understanding physical mechanisms, predictability of the decadal climate variability, in particular, the internally generated variability independent from external atmospheric forcing, remains poorly understood. This study investigates predictability of the decadal climate variability in the southern Indian Ocean using a coupled general circulation model, called SINTEX-F. The ensemble members of the decadal reforecast experiments were initialized with a simple sea surface temperature (SST) nudging scheme. The observed positive and negative peaks during late 1990s and late 2000s are well reproduced in the reforecast experiments initiated from 1994 and 1999, respectively. The experiments initiated from 1994 successfully capture warm SST and high sea level pressure anomalies propagating from the South Atlantic to the southern Indian Ocean. Also, the other experiments initiated from 1999 skillfully predict phase change from a positive to negative peak. These results suggest that the SST-nudging initialization has the essence to capture the predictability of the internally generated decadal climate variability in the southern Indian Ocean.

Regional monitoring of environmental physics climate related anomalies

Science.gov (United States)

El-Askary, Hesham

2004-11-01

Scientific communities have been working in creating and enhancing scientific research programs in which in situ and satellite data as well as remote sensing (RS) technologies are being applied to regional environmental issues. These issues include the effects of climate change on regional flooding, droughts and the impact of human activities as they relate to feedbacks on the global climate. More specifically, one needs to evaluate the potential impact of climatological variability on social, economic, and human activities. In addition, the study of their effects on agriculture, forests, local natural ecosystems and water climate-related resources, is most important. Finally, dust storms and other natural events such as droughts can have great local impacts. Approximately half of the dust in today's atmosphere may be the result of changes to the environment caused by human activities, including agriculture, overgrazing, and deforestation. Climate variability may lead to the occurrence of some severe environmental phenomena like dust storms, hurricanes, tornadoes, floods and droughts. Under normal conditions we can detect different dust effects associated with the movement of storms as well as different rain patterns that do not affect much of the surrounding environment either at regional or global scales. On the other hand, under abnormal climatological conditions, high anomalies of precipitation might occur due to the presence of hurricanes or other events, leading to severe flooding events. In this dissertation, we apply time series analysis techniques to remote sensing and in situ data to detect precipitation and dust storm anomalies and study their behavior on regional scales. The first application is the detection and monitoring of dust storms events over parts of the Middle East and Asia. Dust storms cause health and economic hazards. In this thesis dust storms development is examined based on using remote sensing. It utilizes a combination of optical

Overview of data acquisition system for SST-1 diagnostics

International Nuclear Information System (INIS)

Sharma, Manika; Mansuri, Imran; Raval, Tushar; Sharma, A.L; Pradhan, S.

2016-01-01

Highlights: • An account of architecture and data acquisition activities of SST-1 data acquisition system (DAS) for SST-1 diagnostics and subsystems. • PXI based Data acquisition system and CAMAC based Data acquisition system for slow and fast plasma diagnostics. • SST-1 DAS interface and its communication with SST-1 central control system. Integration of SST-1 DAS with timing system. • SST-1 DAS data archival and data analysis. - Abstract: The recent first phase operations of SST-1 in short pulse mode have provided an excellent opportunity for the essential initial tests and benchmark of the SST-1 Data Acquisition System. This paper describes the SST-1 Data Acquisition systems (DAS), which with its heterogeneous composition and distributed architecture, aims to cover a wide range of slow to fast channels interfaced with a large set of diagnostics. The DAS also provides the essential user interface for data acquisition to cater both on and off-line data usage. The central archiving and retrieval service is based on a dual step architecture involving a combination of Network Attached Server (NAS) and a Storage Area Network (SAN). SST-1 Data Acquisition Systems have been reliably operated in the SST-1 experimental campaigns. At present different distributed DAS caters the need of around 130 channels from different SST-1 diagnostics and its subsystems. PXI based DAS and CAMAC based DAS have been chosen to cater the need, with sampling rates varying from 10Ksamples/sec to 1Msamples/sec. For these large sets of channels acquiring from individual diagnostics and subsystems has been a combined setup, subjected to a gradual phase of optimization and tests resulting into a series of improvisations over the recent operations. In order to facilitate a reliable data acquisition, the model further integrates the objects of the systems with the Central Control System of SST-1 using the TCP/IP communication. The associated DAS software essentially addresses the

Overview of data acquisition system for SST-1 diagnostics

Energy Technology Data Exchange (ETDEWEB)

Sharma, Manika, E-mail: bithi@ipr.res.in; Mansuri, Imran; Raval, Tushar; Sharma, A.L; Pradhan, S.

2016-11-15

Highlights: • An account of architecture and data acquisition activities of SST-1 data acquisition system (DAS) for SST-1 diagnostics and subsystems. • PXI based Data acquisition system and CAMAC based Data acquisition system for slow and fast plasma diagnostics. • SST-1 DAS interface and its communication with SST-1 central control system. Integration of SST-1 DAS with timing system. • SST-1 DAS data archival and data analysis. - Abstract: The recent first phase operations of SST-1 in short pulse mode have provided an excellent opportunity for the essential initial tests and benchmark of the SST-1 Data Acquisition System. This paper describes the SST-1 Data Acquisition systems (DAS), which with its heterogeneous composition and distributed architecture, aims to cover a wide range of slow to fast channels interfaced with a large set of diagnostics. The DAS also provides the essential user interface for data acquisition to cater both on and off-line data usage. The central archiving and retrieval service is based on a dual step architecture involving a combination of Network Attached Server (NAS) and a Storage Area Network (SAN). SST-1 Data Acquisition Systems have been reliably operated in the SST-1 experimental campaigns. At present different distributed DAS caters the need of around 130 channels from different SST-1 diagnostics and its subsystems. PXI based DAS and CAMAC based DAS have been chosen to cater the need, with sampling rates varying from 10Ksamples/sec to 1Msamples/sec. For these large sets of channels acquiring from individual diagnostics and subsystems has been a combined setup, subjected to a gradual phase of optimization and tests resulting into a series of improvisations over the recent operations. In order to facilitate a reliable data acquisition, the model further integrates the objects of the systems with the Central Control System of SST-1 using the TCP/IP communication. The associated DAS software essentially addresses the

New gravity anomaly map of Taiwan and its surrounding regions with some tectonic interpretations

Science.gov (United States)

Doo, Wen-Bin; Lo, Chung-Liang; Hsu, Shu-Kun; Tsai, Ching-Hui; Huang, Yin-Sheng; Wang, Hsueh-Fen; Chiu, Shye-Donq; Ma, Yu-Fang; Liang, Chin-Wei

2018-04-01

In this study, we compiled recently collected (from 2005 to 2015) and previously reported (published and open access) gravity data, including land, shipborne and satellite-derived data, for Taiwan and its surrounding regions. Based on the cross-over error analysis, all data were adjusted; and, new Free-air gravity anomalies were obtained, shedding light on the tectonics of the region. To obtain the Bouguer gravity anomalies, the densities of land terrain and marine sediments were assumed to be 2.53 and 1.80 g/cm3, respectively. The updated gravity dataset was gridded with a spacing of one arc-minute. Several previously unnoticed gravity features are revealed by the new maps and can be used in a broad range of applications: (1) An isolated gravity high is located between the Shoushan and the Kaoping Canyon off southwest Taiwan. (2) Along the Luzon Arc, both Free-air and Bouguer gravity anomaly maps reveal a significant gravity discontinuity feature at the latitude of 21°20‧N. (3) In the southwestern Okinawa Trough, the NE-SW trending cross-back-arc volcanic trail (CBVT) marks the low-high gravity anomaly (both Free-air and Bouguer) boundary.

The prevalence of dental anomalies in the Western region of saudi arabia.

Science.gov (United States)

Afify, Ahmed R; Zawawi, Khalid H

2012-01-01

Objective. The aim of this cross-sectional study was to investigate the prevalence of dental anomalies that could be a cause of malocclusion in the western region of Saudi Arabia. Materials and Methods. A retrospective study of 878 digital orthopantomograms (OPGs) taken of patients, age ranging between 12 and 30 years, who presented to treatment at the Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia between 2002 and 2011. The OPGs and dental records were reviewed for congenitally missing teeth, supernumerary teeth, impactions, ectopic eruption, transposition, germination, fusion, dilacerations, taurodontism, dens in dent, and any other unusual conditions that can be assessed with OPG. Results. The prevalence of patient that exhibited at least one dental anomaly was 396 (45.1%) patients. The prevalence of congenitally missing teeth was 226 (25.7%), impacted teeth 186 (21.1%), dilacerated teeth 10 (1.1%), supernumerary teeth 3 (0.3%), odontoma 1 (0.1%), and taurodontism was also 1 case (0.1%) of the total radiographs reviewed. Conclusions. Congenitally missing teeth were found to be the most prevalent anomaly (25.7%), and the second frequent anomaly was impacted teeth (21.1%), whereas root dilacerations, supernumerary teeth, and taurodontism were the least frequent anomalies (1.1%, 0.3% and 0.1%, resp.).

Predictable patterns of the May-June rainfall anomaly over East Asia

Science.gov (United States)

Xing, Wen; Wang, Bin; Yim, So-Young; Ha, Kyung-Ja

2017-02-01

During early summer (May-June, MJ), East Asia (EA) subtropical front is a defining feature of Asian monsoon, which produces the most prominent precipitation band in the global subtropics. Here we show that dynamical prediction of early summer EA (20°N-45°N, 100°E-130°E) rainfall made by four coupled climate models' ensemble hindcast (1979-2010) yields only a moderate skill and cannot be used to estimate predictability. The present study uses an alternative, empirical orthogonal function (EOF)-based physical-empirical (P-E) model approach to predict rainfall anomaly pattern and estimate its potential predictability. The first three leading modes are physically meaningful and can be, respectively, attributed to (a) the interaction between the anomalous western North Pacific subtropical high and underlying Indo-Pacific warm ocean, (b) the forcing associated with North Pacific sea surface temperature (SST) anomaly, and (c) the development of equatorial central Pacific SST anomalies. A suite of P-E models is established to forecast the first three leading principal components. All predictors are 0 month ahead of May, so the prediction here is named as a 0 month lead prediction. The cross-validated hindcast results demonstrate that these modes may be predicted with significant temporal correlation skills (0.48-0.72). Using the predicted principal components and the corresponding EOF patterns, the total MJ rainfall anomaly was hindcasted for the period of 1979-2015. The time-mean pattern correlation coefficient (PCC) score reaches 0.38, which is significantly higher than dynamical models' multimodel ensemble skill (0.21). The estimated potential maximum attainable PCC is around 0.65, suggesting that the dynamical prediction models may have large rooms to improve. Limitations and future work are discussed.

Relation between Ocean SST Dipoles and Downwind Continental Croplands Assessed for Early Management Using Satellite-based Photosynthesis Models

Science.gov (United States)

Kaneko, Daijiro

2015-04-01

Crop-monitoring systems with the unit of carbon-dioxide sequestration for environmental issues related to climate adaptation to global warming have been improved using satellite-based photosynthesis and meteorological conditions. Early management of crop status is desirable for grain production, stockbreeding, and bio-energy providing that the seasonal climate forecasting is sufficiently accurate. Incorrect seasonal forecasting of crop production can damage global social activities if the recognized conditions are unsatisfied. One cause of poor forecasting related to the atmospheric dynamics at the Earth surface, which reflect the energy budget through land surface, especially the oceans and atmosphere. Recognition of the relation between SST anomalies (e.g. ENSO, Atlantic Niño, Indian dipoles, and Ningaloo Niño) and crop production, as expressed precisely by photosynthesis or the sequestrated-carbon rate, is necessary to elucidate the mechanisms related to poor production. Solar radiation, surface air temperature, and water stress all directly affect grain vegetation photosynthesis. All affect stomata opening, which is related to the water balance or definition by the ratio of the Penman potential evaporation and actual transpiration. Regarding stomata, present data and reanalysis data give overestimated values of stomata opening because they are extended from wet models in forests rather than semi-arid regions commonly associated with wheat, maize, and soybean. This study applies a complementary model based on energy conservation for semi-arid zones instead of the conventional Penman-Monteith method. Partitioning of the integrated Net PSN enables precise estimation of crop yields by modifying the semi-closed stomata opening. Partitioning predicts production more accurately using the cropland distribution already classified using satellite data. Seasonal crop forecasting should include near-real-time monitoring using satellite-based process crop models to avoid

Preliminary results from the ESA STSE project on SST diurnal variability, its regional extent and implications in atmospheric modelling (SSTDV:R.EX.–IM.A.M.)

DEFF Research Database (Denmark)

Karagali, Ioanna; Hasager, Charlotte Bay; Høyer, Jacob L.

2013-01-01

This study presents some preliminary results of the ESA Support To Science Element (STSE) funded project on the Diurnal Variability of the Sea Surface Temperature, regarding its Regional Extend and Implications in Atmospheric Modelling (SSTDV:R.EX.–IM.A.M.). Comparisons of SEVIRI SST with AATSR...

Performance Evaluation of CRW Reef-Scale and Broad-Scale SST-Based Coral Monitoring Products in Fringing Reef Systems of Tobago

Directory of Open Access Journals (Sweden)

Shaazia S. Mohammed

2015-12-01

Full Text Available Satellite-derived sea surface temperature (SST is used to monitor coral bleaching through the National Oceanic and Atmospheric Administration’s Coral Reef Watch (CRW Decision Support System (DSS. Since 2000, a broad-scale 50 km SST was used to monitor thermal stress for coral reefs globally. However, some discrepancies were noted when applied to small-scale fringing coral reefs. To address this, CRW created a new DSS, specifically targeted at or near reef scales. Here, we evaluated the new reef-scale (5 km resolution products using in situ temperature data and coral bleaching surveys which were also compared with the heritage broad-scale (50 km for three reefs (Buccoo Reef, Culloden and Speyside of the southern Caribbean island of Tobago. Seasonal and annual biases indicated the new 5 km SST generally represents the conditions at these reefs more accurately and more consistently than the 50 km SST. Consistency between satellite and in situ temperature data influences the performance of anomaly-based predictions of bleaching: the 5 km DHW product showed better consistency with bleaching observations than the 50 km product. These results are the first to demonstrate the improvement of the 5 km products over the 50 km predecessors and support their use in monitoring thermal stress of reefs in the southern Caribbean.

Seismic yield verification and a regional M/sub s/ vs m/sub b/ anomaly

International Nuclear Information System (INIS)

Rodean, H.C.

1976-01-01

The surface-wave magnitude (M/sub s/) and body-wave magnitude (m/sub b/) data for explosions in the western United States are anomalous with respect to such data for the Aleutians, the Sahara, and the USSR. The degree of this anomaly is such that it has significant implications with respect to using magnitude vs yield data from the Nevada Test Site to estimate the yields of explosions in other parts of the world. This report presents the results of a literature survey of seismic and other geophysical evidence relating to this anomaly. The geology and geophysics of three regions are considered: (1) the Basin and Range province in the western United States, (2) the Baikal rift zone in the USSR, and (3) central Kazakhstan in the USSR. Complete geophysical models, which would be of value in explaining the M/sub s/ vs m/sub b/ anomaly, have not been developed for any of these regions

NOAA Optimum Interpolation (OI) SST V2

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The optimum interpolation (OI) sea surface temperature (SST) analysis is produced weekly on a one-degree grid. The analysis uses in situ and satellite SST's plus...

Geophysical Global Modeling for Extreme Crop Production Using Photosynthesis Models Coupled to Ocean SST Dipoles

Science.gov (United States)

Kaneko, D.

2016-12-01

Climate change appears to have manifested itself along with abnormal meteorological disasters. Instability caused by drought and flood disasters is producing poor harvests because of poor photosynthesis and pollination. Fluctuations of extreme phenomena are increasing rapidly because amplitudes of change are much greater than average trends. A fundamental cause of these phenomena derives from increased stored energy inside ocean waters. Geophysical and biochemical modeling of crop production can elucidate complex mechanisms under seasonal climate anomalies. The models have progressed through their combination with global climate reanalysis, environmental satellite data, and harvest data on the ground. This study examined adaptation of crop production to advancing abnormal phenomena related to global climate change. Global environmental surface conditions, i.e., vegetation, surface air temperature, and sea surface temperature observed by satellites, enable global modeling of crop production and monitoring. Basic streams of the concepts of modeling rely upon continental energy flow and carbon circulation among crop vegetation, land surface atmosphere combining energy advection from ocean surface anomalies. Global environmental surface conditions, e.g., vegetation, surface air temperature, and sea surface temperature observed by satellites, enable global modeling of crop production and monitoring. The method of validating the modeling relies upon carbon partitioning in biomass and grains through carbon flow by photosynthesis using carbon dioxide unit in photosynthesis. Results of computations done for this study show global distributions of actual evaporation, stomata opening, and photosynthesis, presenting mechanisms related to advection effects from SST anomalies in the Pacific, Atlantic, and Indian oceans on global and continental croplands. For North America, climate effects appear clearly in severe atmospheric phenomena, which have caused drought and forest fires

Coral Records of 20th Century Central Tropical Pacific SST and Salinity: Signatures of Natural and Anthropogenic Climate Change

Science.gov (United States)

Nurhati, I. S.; Cobb, K.; Di Lorenzo, E.

2011-12-01

Accurate forecasts of regional climate changes in many regions of the world largely depend on quantifying anthropogenic trends in tropical Pacific climate against its rich background of interannual to decadal-scale climate variability. However, the strong natural climate variability combined with limited instrumental climate datasets have obscured potential anthropogenic climate signals in the region. Here, we present coral-based sea-surface temperature (SST) and salinity proxy records over the 20th century (1898-1998) from the central tropical Pacific - a region sensitive to El Niño-Southern Oscillation (ENSO) whose variability strongly impacts the global climate. The SST and salinity proxy records are reconstructed via coral Sr/Ca and the oxygen isotopic composition of seawater (δ18Osw), respectively. On interannual (2-7yr) timescales, the SST proxy record tracks both eastern- and central-Pacific flavors of ENSO variability (R=0.65 and R=0.67, respectively). Interannual-scale salinity variability in our coral record highlights profound differences in precipitation and ocean advections during the two flavors of ENSO. On decadal (8yr-lowpassed) timescales, the central tropical Pacific SST and salinity proxy records are controlled by different sets of dynamics linked to the leading climate modes of North Pacific climate variability. Decadal-scale central tropical Pacific SST is highly correlated to the recently discovered North Pacific Gyre Oscillation (NPGO; R=-0.85), reflecting strong dynamical links between the central Pacific warming mode and extratropical decadal climate variability. Whereas decadal-scale salinity variations in the central tropical Pacific are significantly correlated with the Pacific Decadal Oscillation (PDO; R=0.54), providing a better understanding on low-frequency salinity variability in the region. Having characterized natural climate variability in this region, the coral record shows a +0.5°C warming trend throughout the last century

Impacts of the leading modes of tropical Indian Ocean sea surface temperature anomaly on sub-seasonal evolution of the circulation and rainfall over East Asia during boreal spring and summer

Science.gov (United States)

Liu, Senfeng; Duan, Anmin

2017-02-01

The two leading modes of the interannual variability of the tropical Indian Ocean (TIO) sea surface temperature (SST) anomaly are the Indian Ocean basin mode (IOBM) and the Indian Ocean dipole mode (IODM) from March to August. In this paper, the relationship between the TIO SST anomaly and the sub-seasonal evolution of the circulation and rainfall over East Asia during boreal spring and summer is investigated by using correlation analysis and composite analysis based on multi-source observation data from 1979 to 2013, together with numerical simulations from an atmospheric general circulation model. The results indicate that the impacts of the IOBM on the circulation and rainfall over East Asia vary remarkably from spring to summer. The anomalous anticyclone over the tropical Northwest Pacific induced by the warm IOBM is closely linked with the Pacific-Japan or East Asia-Pacific teleconnection pattern, which persists from March to August. In the upper troposphere over East Asia, the warm phase of the IOBM generates a significant anticyclonic response from March to May. In June and July, however, the circulation response is characterized by enhanced subtropical westerly flow. A distinct anomalous cyclone is found in August. Overall, the IOBM can exert significant influence on the western North Pacific subtropical high, the South Asian high, and the East Asian jet, which collectively modulate the precipitation anomaly over East Asia. In contrast, the effects of the IODM on the climate anomaly over East Asia are relatively weak in boreal spring and summer. Therefore, studying the impacts of the TIO SST anomaly on the climate anomaly in East Asia should take full account of the different sub-seasonal response during boreal spring and summer.

Why were cool SST anomalies absent in the Bay of Bengal during the 1997 Indian Ocean Dipole event?

Digital Repository Service at National Institute of Oceanography (India)

Rao, S.A.; Gopalakrishna, V.V.; Shetye, S.R.; Yamagata, T.

surface temperature anomalies (C176C) (middle row) and NCEP outgoing longwave radiation anomalies (watts.m C02 ) (bottom row) during September 1997 (first column), November 1997 (middle column) and January 1998 (right column). XBT lines (in pink) whose...

Nitrogen Gas Heating and Supply System for SST-1 Tokamak

International Nuclear Information System (INIS)

Khan, Ziauddin; Pathan, Firozkhan; Paravastu, Yuvakiran; George, Siju; Ramesh, Gattu; Bindu, Hima; Raval, Dilip C.; Thankey, Prashant; Dhanani, Kalpesh; Pradhan, Subrata

2013-01-01

Steady State Tokamak (SST-1) vacuum vessel baking as well as baking of the first wall components of SST-1 are essential to plasma physics experiments. Under a refurbishment spectrum of SST-1, the nitrogen gas heating and supply system has been fully refurbished. The SST-1 vacuum vessel consists of ultra-high vacuum (UHV) compatible eight modules and eight sectors. Rectangular baking channels are embedded on each of them. Similarly, the SST-1 plasma facing components (PFC) are comprised of modular graphite diverters and movable graphite based limiters. The nitrogen gas heating and supply system would bake the plasma facing components at 350°C and the SST-1 vacuum vessel at 150°C over an extended duration so as to remove water vapour and other absorbed gases. An efficient PLC based baking facility has been developed and implemented for monitoring and control purposes. This paper presents functional and operational aspects of a SST-1 nitrogen gas heating and supply system. Some of the experimental results obtained during the baking of SST-1 vacuum modules and sectors are also presented here. (fusion engineering)

The Coral Reef Temperature Anomaly Database (CoRTAD) - Global, 4 km, Sea Surface Temperature and Related Thermal Stress Metrics for 1985-2005 (NODC Accession 0044419)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Coral Reef Temperature Anomaly Database (CoRTAD) is a collection of sea surface temperature (SST) and related thermal stress metrics, developed specifically for...

The 2014-2015 Warming Anomaly in the Southern California Current System: Glider Observations

Science.gov (United States)

Zaba, K. D.; Rudnick, D. L.

2016-02-01

During 2014-2015, basin-wide patterns of oceanic and atmospheric anomalies affected surface waters throughout the North Pacific Ocean. We present regional physical and biological effects of the warming, as observed by our autonomous underwater gliders in the southern California Current System (SCCS). Established in 2006, the California Glider Network provides sustained subsurface observations for monitoring the coastal effects of large-scale climate variability. Along repeat sections that extend to 350-500 km in offshore distance and 500 m in depth, Spray gliders have continuously occupied CalCOFI lines 66.7, 80, and 90 for nearly nine years. Following a sawtooth trajectory, the gliders complete each dive in approximately 3 hours and over 3 km. Measured variables include pressure, temperature, salinity, chlorophyll fluorescence, and velocity. For each of the three lines, a comprehensive climatology has been constructed from the multiyear timeseries. The ongoing surface-intensified warming anomaly, which began locally in early 2014 and persists through present, is unprecedented in the glider climatology. Reaching up to 5°C, positive temperature anomalies have been generally confined to the upper 50 m and persistent for over 20 months. The timing of the warming was in phase along each glider line but out of phase with equatorial SST anomalies, suggesting a decoupling of tropical and mid-latitude dynamics. Concurrent physical oceanographic anomalies included a depressed thermocline and high stratification. An induced biological response was apparent in the deepening of the subsurface chlorophyll fluorescence maximum. Ancillary atmospheric data from the NCEP North American Mesoscale (NAM) model indicate that a combination of surface forcing anomalies, namely high downward heat flux and weak wind stress magnitude, caused the unusual warm, downwelling conditions. With a strong El Niño event in the forecast for winter 2015-2016, our sustained glider network will

Saliency U-Net: A regional saliency map-driven hybrid deep learning network for anomaly segmentation

Science.gov (United States)

Karargyros, Alex; Syeda-Mahmood, Tanveer

2018-02-01

Deep learning networks are gaining popularity in many medical image analysis tasks due to their generalized ability to automatically extract relevant features from raw images. However, this can make the learning problem unnecessarily harder requiring network architectures of high complexity. In case of anomaly detection, in particular, there is often sufficient regional difference between the anomaly and the surrounding parenchyma that could be easily highlighted through bottom-up saliency operators. In this paper we propose a new hybrid deep learning network using a combination of raw image and such regional maps to more accurately learn the anomalies using simpler network architectures. Specifically, we modify a deep learning network called U-Net using both the raw and pre-segmented images as input to produce joint encoding (contraction) and expansion paths (decoding) in the U-Net. We present results of successfully delineating subdural and epidural hematomas in brain CT imaging and liver hemangioma in abdominal CT images using such network.

Interannual tropical Pacific sea surface temperature anomalies teleconnection to Northern Hemisphere atmosphere in November

Science.gov (United States)

King, Martin P.; Herceg-Bulić, Ivana; Kucharski, Fred; Keenlyside, Noel

2018-03-01

We investigate the Northern Hemisphere atmospheric circulation anomalies associated to the sea surface temperature (SST) anomalies that are related to the eastern-Pacific and central-Pacific El Nino-Southern Oscillations in the late autumn (November). This research is motivated by the need for improving understanding of the autumn climate conditions which can impact on winter climate, as well as the relative lack of study on the boreal autumn climate processes compared to winter. Using reanalysis and SST datasets available from the late nineteenth century through the recent years, we found that there are two major atmospheric responses; one is a hemispheric-wide wave number-4 pattern, another has a more annular pattern. Both of these project on the East Atlantic pattern (southward-shifted North Atlantic Oscillation) in the Atlantic sector. Which of the patterns is active is suggested to depend on the background mean flow, with the annular anomaly active in the most recent decades, while the wave-4 pattern in the decades before. This switch is associated with a change of correlation sign in the North Pacific. We discuss the robustness of this finding. The ability of two atmospheric general circulation models (ICTP-AGCM and ECHAM-AGCM) to reproduce the teleconnections is also examined. Evidence provided shows that the wave-4 pattern and the East Atlantic pattern signals can be reproduced by the models, while the shift from this to an annular response for the recent years is not found conclusively.

Effects of Northern Hemisphere Sea Surface Temperature Changes on the Global Air Quality

Science.gov (United States)

Yi, K.; Liu, J.

2017-12-01

The roles of regional sea surface temperature (SST) variability on modulating the climate system and consequently the air quality are investigated using the Community Earth System Model (CESM). Idealized, spatially uniform SST anomalies of +/- 1 °C are superimposed onto the North Pacific, North Atlantic, and North Indian Oceans individually. Ignoring the response of natural emissions, our simulations suggest large seasonal and regional variability of surface O3 and PM2.5 concentrations in response to SST anomalies, especially during boreal summers. Increasing the SST by 1 °C in one of the oceans generally decreases the surface O3 concentrations from 1 to 5 ppbv while increases the anthropogenic PM2.5 concentrations from 0.5 to 3 µg m-3. We implement the integrated process rate (IPR) analysis in CESM and find that meteorological transport in response to SST changes is the key process causing air pollutant perturbations in most cases. During boreal summers, the increase in tropical SST over different ocean basins enhances deep convection, which significantly increases the air temperature over the upper troposphere and trigger large-scale subsidence over nearby and remote regions. These processes tend to increase tropospheric stability and suppress rainfall at lower mid-latitudes. Consequently, it reduces the vertical transport of O3 to the surface while facilitating the accumulation of PM2.5 concentrations over most regions. In addition, this regional SST warming may also considerably suppress intercontinental transport of air pollution as confirmed with idealized CO-like tracers. Our findings indicate a robust linkage between basin-scale SST variability and regional air quality, which can help local air quality management.

Design and thermal-hydraulic analysis of PFC baking for SST-1 Tokamak

International Nuclear Information System (INIS)

Chaudhuri, Paritosh; Reddy, D. Chenna; Khirwadkar, S.; Prakash, N. Ravi; Santra, P.; Saxena, Y.C.

2001-01-01

The Steady-State Superconducting Tokamak (SST-1) is a medium-size tokamak with super-conducting magnetic field coils. Plasma facing components (PFC) of the SST-1, consisting of divertors, passive stabilisers, baffles, and poloidal limiters, are designed to be compatible for steady-state operation. Except for the poloidal limiters, all other PFC are structurally continuous in the toroidal direction. As SST-1 is designed to run double-null divertor plasmas, these components also have up-down symmetry. A closed divertor configuration is chosen to produce high recycling and high pumping speed in the divertor region. The passive stabilisers are located close to the plasma to provide stability against the vertical instability of the elongated plasma. The main consideration in the design of the PFC is the steady-state heat removal of up to 1 MW/m 2 . In addition to removing high heat fluxes, the PFC are also designed to be compatible for baking at 350 deg. C. Different flow parameters and various tube layouts have been examined to select the optimum thermal-hydraulic parameters and tube layout for different PFC of SST-1. Thermal response of the PFC during baking has been performed analytically (using a Fortran code) and two-dimensional finite element analysis using ANSYS. The detailed thermal hydraulics and thermal responses of PFC baking is presented in this paper

Design and thermal-hydraulic analysis of PFC baking for SST-1 Tokamak

Energy Technology Data Exchange (ETDEWEB)

Chaudhuri, Paritosh E-mail: paritosh@ipr.res.in; Reddy, D. Chenna; Khirwadkar, S.; Prakash, N. Ravi; Santra, P.; Saxena, Y.C

2001-09-01

The Steady-State Superconducting Tokamak (SST-1) is a medium-size tokamak with super-conducting magnetic field coils. Plasma facing components (PFC) of the SST-1, consisting of divertors, passive stabilisers, baffles, and poloidal limiters, are designed to be compatible for steady-state operation. Except for the poloidal limiters, all other PFC are structurally continuous in the toroidal direction. As SST-1 is designed to run double-null divertor plasmas, these components also have up-down symmetry. A closed divertor configuration is chosen to produce high recycling and high pumping speed in the divertor region. The passive stabilisers are located close to the plasma to provide stability against the vertical instability of the elongated plasma. The main consideration in the design of the PFC is the steady-state heat removal of up to 1 MW/m{sup 2}. In addition to removing high heat fluxes, the PFC are also designed to be compatible for baking at 350 deg. C. Different flow parameters and various tube layouts have been examined to select the optimum thermal-hydraulic parameters and tube layout for different PFC of SST-1. Thermal response of the PFC during baking has been performed analytically (using a Fortran code) and two-dimensional finite element analysis using ANSYS. The detailed thermal hydraulics and thermal responses of PFC baking is presented in this paper.

Isostatic and Decompensative Gravity Anomalies of the Arabian Plate and Surrounding Regions: a Key for the Crustal Structure

Science.gov (United States)

Kaban, M. K.; El Khrepy, S.; Al-Arifi, N. S.

2016-12-01

The isostatic anomalies are often considered as one of the most useful correction of the gravity field for investigation of the upper crust structure in many practical applications. By applying this correction, a substantial part of the effect of deep density heterogeneity, which dominates in the Bouguer gravity anomaly, can be removed. With this approach, it is not even necessary to know the deep density structure of the crust and upper mantle in details; it is sufficient to prescribe some type of compensation (regional vs. local) and a compensation depth. However, even when all the parameters are chosen correctly, this reduction of the gravity field does not show the full gravity effect of unknown anomalies in the crust. The last ones should be also compensated to some extent; therefore their impact is substantially reduced by the isostatic compensation. Long ago (Cordell et al., 1991), it was suggested a so-called decompensative correction of the isostatic anomalies, which provides a possibility to separate these effects. However, the decompensative correction is very sensitive to the parameters of the compensation scheme. In the present study we analyse the ways to choose these parameters and extend this approach by assuming a possibility for the regional compensation via elastic deformations of the lithosphere. Based on this technique, we estimate the isostatic and decompensative anomalies for the Arabian plate and surrounding regions. The parameters of the isostatic model are chosen based on previous studies. It was demonstrated that the decompensative correction is very significant at the mid-range wavelengths and may exceed 100 mGal, therefore ignoring this effect would lead to wrong conclusions about the upper crust structure. The total amplitude of the decompensative anomalies reaches ±250 mGal, evidencing for both, large density anomalies of the upper crust (including sediments) and strong isostatic disturbances of the lithosphere. These results improve

The Coral Reef Temperature Anomaly Database (CoRTAD) Version 3 - Global, 4 km Sea Surface Temperature and Related Thermal Stress Metrics for 1982-2009 (NODC Accession 0068999)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Coral Reef Temperature Anomaly Database (CoRTAD) is a collection of sea surface temperature (SST) and related thermal stress metrics, developed specifically for...

The Coral Reef Temperature Anomaly Database (CoRTAD) Version 2 - Global, 4 km Sea Surface Temperature and Related Thermal Stress Metrics for 1982-2008 (NODC Accession 0054501)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Coral Reef Temperature Anomaly Database (CoRTAD) is a collection of sea surface temperature (SST) and related thermal stress metrics, developed specifically for...

The Coral Reef Temperature Anomaly Database (CoRTAD) Version 1 - Global, 4 km, Sea Surface Temperature and Related Thermal Stress Metrics for 1985-2005 (NODC Accession 0044419)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Coral Reef Temperature Anomaly Database (CoRTAD) is a collection of sea surface temperature (SST) and related thermal stress metrics, developed specifically for...

How El-Nino affects Ethiopian summer rainfall

Science.gov (United States)

Gleixner, Stephanie; Keenlyside, Noel; Viste, Ellen

2016-04-01

Ethiopian economy and society are strongly dependent on agriculture and therefore rainfall. Reliable forecasts for the rainy seasons are important to allow for agricultural planning and drought preparations. The operational seasonal forecasts for Ethiopia are based on analogue methods relying mainly on sea surface temperature (SST) indices. A better understanding of the physical links between Ethiopian rainfall and SST may help to improve forecasts. The highest rainfall rates are observed in the Kiremt season (defined as JJAS), which is the rainy season in Central and Northwestern Ethiopia. Kiremt rainfall shows clear negative correlation with Central Pacific SST, linking dry Ethiopian summers with ENSO-like warm SST anomalies. We use the atmosphere general circulation model Echam5.3 to investigate the physical link between Pacific SST anomalies and Kiremt rainfall. We compare a historical simulation with a T106 horizontal resolution (~ 1.125°), forced with reconstructed SST data, to gauge-based rainfall observations for the time period of 1961 to 2009. Composite analysis for model and observations show warm SST anomalies in the Central Pacific and a corresponding large-scale circulation anomaly with subsidence over Ethiopia in dry Kiremt seasons. Horizontal wind fields show a slow-down of the whole Indian monsoon system with a weaker Tropical Easterly Jet (TEJ) and a weaker East African Low-Level Jet (EALLJ) in these summers. We conducted a sensitivity experiment with El Nino like SST anomalies in the Central Pacific with the same Echam version. Its results show that warm Pacific SST anomalies cause dry summer conditions over Ethiopia. While the large-scale subsidence over East Africa is present in the experiment, there is no significant weakening of the Indian monsoon system. We rather find an anomalous circulation cell over Northern Africa with westerlies at 100-200 hPa and easterlies below 500 hPa. The anomalous easterly flow in the lower and middle

Hydroclimatic variability in the Lake Mondsee region and its relationships with large-scale climate anomaly patterns

Science.gov (United States)

Rimbu, Norel; Ionita, Monica; Swierczynski, Tina; Brauer, Achim; Kämpf, Lucas; Czymzik, Markus

2017-04-01

Flood triggered detrital layers in varved sediments of Lake Mondsee, located at the northern fringe of the European Alps (47°48'N,13°23'E), provide an important archive of regional hydroclimatic variability during the mid- to late Holocene. To improve the interpretation of the flood layer record in terms of large-scale climate variability, we investigate the relationships between observational hydrological records from the region, like the Mondsee lake level, the runoff of the lake's main inflow Griesler Ache, with observed precipitation and global climate patterns. The lake level shows a strong positive linear trend during the observational period in all seasons. Additionally, lake level presents important interannual to multidecadal variations. These variations are associated with distinct seasonal atmospheric circulation patterns. A pronounced anomalous anticyclonic center over the Iberian Peninsula is associated with high lake levels values during winter. This center moves southwestward during spring, summer and autumn. In the same time, a cyclonic anomaly center is recorded over central and western Europe. This anomalous circulation extends southwestward from winter to autumn. Similar atmospheric circulation patterns are associated with river runoff and precipitation variability from the region. High lake levels are associated with positive local precipitation anomalies in all seasons as well as with negative local temperature anomalies during spring, summer and autumn. A correlation analysis reveals that lake level, runoff and precipitation variability is related to large-scale sea surface temperature anomaly patterns in all seasons suggesting a possible impact of large-scale climatic modes, like the North Atlantic Oscillation and Atlantic Multidecadal Oscillation on hydroclimatic variability in the Lake Mondsee region. The results presented in this study can be used for a more robust interpretation of the long flood layer record from Lake Mondsee sediments

Cleft palate with/without cleft lip in French children: radiographic evaluation of prevalence, location and coexistence of dental anomalies inside and outside cleft region.

Science.gov (United States)

Mangione, Francesca; Nguyen, Laure; Foumou, Nathalie; Bocquet, Emmanuelle; Dursun, Elisabeth

2018-03-01

Prevalence of dental anomalies in cleft patients is higher than that in general population. The objectives of this study were to assess the prevalence of dental anomalies and their coexistence in French children with cleft and, then, to investigate the relation between the dental anomalies and the cleft type. Seventy-four non-syndromic cleft patients (6-16 years old) from Lille Regional University and Mondor-Chenevier Hospitals (France) were included. Clefts were classified as right/left unilateral cleft lip and palate (UCLP), bilateral cleft lip and palate (BCLP) and cleft palate (CP). Dental anomalies were investigated on panoramic radiographs and categorized as agenesis, supernumerary teeth, incisor rotations, impacted canines and shape anomalies. Prevalence and gender distribution of dental anomalies, mean number of affected teeth per patient, agenesis occurrence and location, and coexistence of dental anomalies were analysed by cleft type. 96.0% of patients presented at least one dental anomaly (agenesis 83.8%, incisor rotations 25.7%, shape anomalies 21.6%, impacted canines 18.9%, supernumerary teeth 8.1%). BCLP patients had a higher number of affected teeth, and left UCLP patients had a higher one compared to right UCLP patients. Distribution of inside (45.3%) and outside (54.7%) cleft region agenesis was similar. Adjacent (31.8%) and not adjacent (33.3%) combined dental anomalies were often encountered. Dental anomalies were localized inside as well as outside cleft region and were often associated with each other. BCLP patients were more affected. Early radiographic evaluation allows a comprehensive diagnosis of inside and outside cleft region anomalies, required for the multidisciplinary dental treatment.

Assessment of Global Forecast Ocean Assimilation Model (FOAM) using new satellite SST data

Science.gov (United States)

Ascione Kenov, Isabella; Sykes, Peter; Fiedler, Emma; McConnell, Niall; Ryan, Andrew; Maksymczuk, Jan

2016-04-01

There is an increased demand for accurate ocean weather information for applications in the field of marine safety and navigation, water quality, offshore commercial operations, monitoring of oil spills and pollutants, among others. The Met Office, UK, provides ocean forecasts to customers from governmental, commercial and ecological sectors using the Global Forecast Ocean Assimilation Model (FOAM), an operational modelling system which covers the global ocean and runs daily, using the NEMO (Nucleus for European Modelling of the Ocean) ocean model with horizontal resolution of 1/4° and 75 vertical levels. The system assimilates salinity and temperature profiles, sea surface temperature (SST), sea surface height (SSH), and sea ice concentration observations on a daily basis. In this study, the FOAM system is updated to assimilate Advanced Microwave Scanning Radiometer 2 (AMSR2) and the Spinning Enhanced Visible and Infrared Imager (SEVIRI) SST data. Model results from one month trials are assessed against observations using verification tools which provide a quantitative description of model performance and error, based on statistical metrics, including mean error, root mean square error (RMSE), correlation coefficient, and Taylor diagrams. A series of hindcast experiments is used to run the FOAM system with AMSR2 and SEVIRI SST data, using a control run for comparison. Results show that all trials perform well on the global ocean and that largest SST mean errors were found in the Southern hemisphere. The geographic distribution of the model error for SST and temperature profiles are discussed using statistical metrics evaluated over sub-regions of the global ocean.

A conceptual prediction model for seasonal drought processes using atmospheric and oceanic standardized anomalies: application to regional drought processes in China

Science.gov (United States)

Liu, Zhenchen; Lu, Guihua; He, Hai; Wu, Zhiyong; He, Jian

2018-01-01

Reliable drought prediction is fundamental for water resource managers to develop and implement drought mitigation measures. Considering that drought development is closely related to the spatial-temporal evolution of large-scale circulation patterns, we developed a conceptual prediction model of seasonal drought processes based on atmospheric and oceanic standardized anomalies (SAs). Empirical orthogonal function (EOF) analysis is first applied to drought-related SAs at 200 and 500 hPa geopotential height (HGT) and sea surface temperature (SST). Subsequently, SA-based predictors are built based on the spatial pattern of the first EOF modes. This drought prediction model is essentially the synchronous statistical relationship between 90-day-accumulated atmospheric-oceanic SA-based predictors and SPI3 (3-month standardized precipitation index), calibrated using a simple stepwise regression method. Predictor computation is based on forecast atmospheric-oceanic products retrieved from the NCEP Climate Forecast System Version 2 (CFSv2), indicating the lead time of the model depends on that of CFSv2. The model can make seamless drought predictions for operational use after a year-to-year calibration. Model application to four recent severe regional drought processes in China indicates its good performance in predicting seasonal drought development, despite its weakness in predicting drought severity. Overall, the model can be a worthy reference for seasonal water resource management in China.

Dental anomalies inside the cleft region in individuals with nonsyndromic cleft lip with or without cleft palate.

Science.gov (United States)

Sá, Jamile; Araújo, Luana; Guimarães, Laís; Maranhão, Samário; Lopes, Gabriela; Medrado, Alena; Coletta, Ricardo; Reis, Silvia

2016-01-01

Individuals with nonsyndromic cleft lip with or without cleft palate (NSCL±P) present high frequency of dental anomalies, which may represent complicating factors for dental treatment. The aim of this study was to investigate the prevalence of dental anomalies inside cleft area in a group of Brazilians with NSCL±P. Retrospective analysis of 178 panoramic radiographs of patients aged from 12 to 45 years old and without history of tooth extraction or orthodontic treatment was performed. Association between cleft type and the prevalence of dental anomalies was assessed by chi-square test with a significance level set at p≤ 0.05. Dental anomalies were found in 88.2% (n=157) of the patients. Tooth agenesis (47.1%), giroversion (20%) and microdontia (15.5%) were the most common anomalies. Individuals with unilateral complete cleft lip and palate (CLP, pdental anomalies inside cleft region in NSCL±P patients, and further demonstrated that patients with unilateral complete CLP and bilateral incomplete CLP were frequently more affected by dental anomalies. Moreover, our results demonstrate that dental anomalies should be considered during dental treatment planning of individuals affected by NSCL±P.

Interannual variability of sea surface temperature and circulation in ...

African Journals Online (AJOL)

Local surface heat flux exchanges driven by the anomalous shortwave radiation dominated the interannual SST variability in the Tanzanian shelf region, with some contribution by the advection of heat anomalies from the North-East Madagascar Current. Farther offshore, the interannual variability of the SST was dominated ...

The Coral Reef Temperature Anomaly Database (CoRTAD) Version 2 - Global, 4 km Sea Surface Temperature and Related Thermal Stress Metrics for 1982-2008 (NODC Accession Number 0054501)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Coral Reef Temperature Anomaly Database (CoRTAD) is a collection of sea surface temperature (SST) and related thermal stress metrics, developed specifically for...

3-D lithospheric structure and regional/residual Bouguer anomalies in the Arabia-Eurasia collision (Iran)

Science.gov (United States)

Jiménez-Munt, I.; Fernãndez, M.; Saura, E.; Vergés, J.; Garcia-Castellanos, D.

2012-09-01

The aim of this work is to propose a first-order estimate of the crustal and lithospheric mantle geometry of the Arabia-Eurasia collision zone and to separate the measured Bouguer anomaly into its regional and local components. The crustal and lithospheric mantle structure is calculated from the geoid height and elevation data combined with thermal analysis. Our results show that Moho depth varies from ˜42 km at the Mesopotamian-Persian Gulf foreland basin to ˜60 km below the High Zagros. The lithosphere is thicker beneath the foreland basin (˜200 km) and thinner underneath the High Zagros and Central Iran (˜140 km). Most of this lithospheric mantle thinning is accommodated under the Zagros mountain belt coinciding with the suture between two different mantle domains on the Sanandaj-Sirjan Zone. The regional gravity field is obtained by calculating the gravimetric response of the 3-D crustal and lithospheric mantle structure obtained by combining elevation and geoid data. The calculated regional Bouguer anomaly differs noticeably from those obtained by filtering or just isostatic methods. The residual gravity anomaly, obtained by subtraction of the regional components to the measured field, is analyzed in terms of the dominating upper crustal structures. Deep basins and areas with salt deposits are characterized by negative values (˜-20 mGal), whereas the positive values are related to igneous and ophiolite complexes and shallow basement depths (˜20 mGal).

Are we near the predictability limit of tropical Indo-Pacific sea surface temperatures?

Science.gov (United States)

Newman, Matthew; Sardeshmukh, Prashant D.

2017-08-01

The predictability of seasonal anomalies worldwide rests largely on the predictability of tropical sea surface temperature (SST) anomalies. Tropical forecast skill is also a key metric of climate models. We find, however, that despite extensive model development, the tropical SST forecast skill of the operational North American Multi-Model Ensemble (NMME) of eight coupled atmosphere-ocean models remains close both regionally and temporally to that of a vastly simpler linear inverse model (LIM) derived from observed covariances of SST, sea surface height, and wind fields. The LIM clearly captures the essence of the predictable SST dynamics. The NMME and LIM skills also closely track and are only slightly lower than the potential skill estimated using the LIM's forecast signal-to-noise ratios. This suggests that the scope for further skill improvement is small in most regions, except in the western equatorial Pacific where the NMME skill is currently much lower than the LIM skill.

Impacts of winter NPO on subsequent winter ENSO: sensitivity to the definition of NPO index

Science.gov (United States)

Chen, Shangfeng; Wu, Renguang

2018-01-01

This study investigates the linkage between boreal winter North Pacific Oscillation (NPO) and subsequent winter El Niño-Southern Oscillation (ENSO) based on seven different NPO indices. Results show that the influence of winter NPO on the subsequent winter El Niño is sensitive to how the NPO is defined. A significant NPO-El Niño connection is obtained when the NPO-related anomalous cyclone over the subtropical North Pacific extends to near-equatorial regions. The anomalous cyclone induces warm sea surface temperature (SST) anomalies through modulating surface heat fluxes. These warm SST anomalies are able to maintain into the following spring and summer through an air-sea coupled process and in turn induce significant westerly wind anomalies over the tropical western Pacific. In contrast, the NPO-El Niño relationship is unclear when the NPO-related anomalous cyclone over the subtropical North Pacific is confined to off-equatorial regions and cannot induce significant warm SST anomalies over the subtropical North Pacific. The present study suggests that definitions of NPO should be taken into account when using NPO to predict ENSO. In particular, we recommend defining the NPO index based on the empirical orthogonal function technique over appropriate region that does not extend too far north.

Sensitivity of Horn of Africa Rainfall to Regional Sea Surface Temperature Forcing

Directory of Open Access Journals (Sweden)

Zewdu T. Segele

2015-05-01

Full Text Available The Abdus Salam International Center for Theoretical Physics (ICTP version 4.4 Regional Climate Model (RegCM4 is used to investigate the rainfall response to cooler/warmer sea surface temperature anomaly (SSTA forcing in the Indian and Atlantic Oceans. The effect of SSTA forcing in a specific ocean basin is identified by ensemble, averaging 10 individual simulations in which a constant or linearly zonally varying SSTA is prescribed in individual basins while specifying the 1971–2000 monthly varying climatological sea surface temperature (SST across the remaining model domain. The nonlinear rainfall response to SSTA amplitude also is investigated by separately specifying +1K, +2K, and +4K SSTA forcing in the Atlantic and Indian Oceans. The simulation results show that warm SSTs over the entire Indian Ocean produce drier conditions across the larger Blue Nile catchment, whereas warming ≥ +2K generates large positive rainfall anomalies exceeding 10 mm·day−1 over drought prone regions of Northeastern Ethiopia. However, the June–September rainy season tends to be wetter (drier when the SST warming (cooling is limited to either the Northern or Southern Indian Ocean. Wet rainy seasons generally are characterized by deepening of the monsoon trough, east of 40°E, intensification of the Mascarene high, strengthening of the Somali low level jet and the tropical easterly jet, enhanced zonal and meridional vertically integrated moisture fluxes, and steeply vertically decreasing moist static energy. The opposite conditions hold for dry monsoon seasons.

Using EVT for Geological Anomaly Design and Its Application in Identifying Anomalies in Mining Areas

Directory of Open Access Journals (Sweden)

Feilong Qin

2016-01-01

Full Text Available A geological anomaly is the basis of mineral deposit prediction. Through the study of the knowledge and characteristics of geological anomalies, the category of extreme value theory (EVT to which a geological anomaly belongs can be determined. Associating the principle of the EVT and ensuring the methods of the shape parameter and scale parameter for the generalized Pareto distribution (GPD, the methods to select the threshold of the GPD can be studied. This paper designs a new algorithm called the EVT model of geological anomaly. These study data on Cu and Au originate from 26 exploration lines of the Jiguanzui Cu-Au mining area in Hubei, China. The proposed EVT model of the geological anomaly is applied to identify anomalies in the Jiguanzui Cu-Au mining area. The results show that the model can effectively identify the geological anomaly region of Cu and Au. The anomaly region of Cu and Au is consistent with the range of ore bodies of actual engineering exploration. Therefore, the EVT model of the geological anomaly can effectively identify anomalies, and it has a high indicating function with respect to ore prospecting.

Changing characteristics of streamflow in the Midwest and its relation to oceanic-atmospheric oscillations

Science.gov (United States)

Thakur, B.; Pathak, P.; Kalra, A.; Ahmad, S.

2016-12-01

The identification of primary drivers of streamflow may prove beneficial in forecasting streamflow in the Midwestern U.S. In the past researches, streamflow in the region have been strongly correlated with El Niño-Southern Oscillation (ENSO), Atlantic Multidecadal Oscillation (AMO) and Pacific Decadal Oscillation (PDO). The present study takes in to account the pre-defined Pacific and Atlantic Ocean regions (e.g., ENSO, PDO, AMO) along with new regions with an intent to identify new significantly correlated regions. This study assesses the interrelationship between sea surface temperatures (SST) anomalies in the Pacific and Atlantic Ocean and seasonal streamflow in the Midwestern U.S. Average Pacific and Atlantic Ocean SST anomalies, were calculated for 2 different 3 month series: September-November and December-February so as to create a lead time varying from 3 to 9 months. Streamflow were averaged for three seasons: spring (April-June), spring-summer (April-August) and summer (June-August). The correlation between streamflow and SST is analyzed using singular value decomposition for a period of 1960-2013. The result of the study showed several regions-other than the known Pacific and Atlantic Ocean regions- that were significantly correlated with streamflow stations. Higher correlation between the climate indices and streamflow were observed as the lead time decreased. The identification of the associations between SST and streamflow and significant SST regions in the Pacific and Atlantic Ocean may enhance the skill of streamflow predictability and water management in the region.

The Coral Reef Temperature Anomaly Database (CoRTAD) Version 5 - Global, 4 km Sea Surface Temperature and Related Thermal Stress Metrics for 1982-2012 (NCEI Accession 0126774)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Version 5 of the Coral Reef Temperature Anomaly Database (CoRTAD) is a global, 4 km, sea surface temperature (SST) and related thermal stress metrics dataset for...

GHRSST Level 4 REMO_OI_SST_5km Regional Foundation Sea Surface Temperature Analysis (GDS version 2)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature (SST) analysis produced daily on an operational basis by the...

Recent predictors of Indian summer monsoon based on Indian and Pacific Ocean SST

Science.gov (United States)

Shahi, Namendra Kumar; Rai, Shailendra; Mishra, Nishant

2018-02-01

This study investigates the relationship between sea surface temperature (SST) of various geographical locations of Indian and Pacific Ocean with the Indian summer monsoon rainfall (ISMR) to identify possible predictors of ISMR. We identified eight SST predictors based on spatial patterns of correlation coefficients between ISMR and SST of the regions mentioned above during the time domain 1982-2013. The five multiple linear regression (MLR) models have been developed by these predictors in various combinations. The stability and performance of these MLR models are verified using cross-validation method and other statistical methods. The skill of forecast to predict observed ISMR from these MLR models is found to be substantially better based on various statistical verification measures. It is observed that the MLR models constructed using the combination of SST indices in tropical and extra tropical Indian and Pacific is able to predict ISMR accurately for almost all the years during the time domain of our study. We tried to propose the physical mechanism of the teleconnection through regression analysis with wind over Indian subcontinent and the eight predictors and the results are in the conformity with correlation coefficient analysis. The robustness of these models is seen by predicting the ISMR during recent independent years of 2014-2017 and found the model 5 is able to predict ISMR accurately in these years also.

Connection of the stratospheric QBO with global atmospheric general circulation and tropical SST. Part II: interdecadal variations

Energy Technology Data Exchange (ETDEWEB)

Hu, Zeng-Zhen [Climate Prediction Center (Room 605), NCEP/NWS/NOAA, Camp Springs, MD (United States); Center for Ocean-Land-Atmosphere Studies, Calverton, MD (United States); Huang, Bohua; Kinter, James L. [Center for Ocean-Land-Atmosphere Studies, Calverton, MD (United States); George Mason University, Department of Atmospheric, Oceanic, and Earth Sciences, College of Science, Fairfax, VA (United States); Wu, Zhaohua [Florida State University, Department of Earth, Ocean, and Atmospheric Science, and Center for Ocean-Atmospheric Prediction Studies, Tallahassee, FL (United States); Kumar, Arun [Climate Prediction Center (Room 605), NCEP/NWS/NOAA, Camp Springs, MD (United States)

2012-01-15

The interdecadal variation of the association of the stratospheric quasi-biennial oscillation (QBO) with tropical sea surface temperature (SST) anomalies (SSTA) and with the general circulation in the troposphere and lower stratosphere is examined using the ERA40 and NCEP/NCAR reanalyses, as well as other observation-based analyses. It is found that the relationship between the QBO and tropical SSTA changed once around 1978-1980, and again in 1993-1995. During 1966-1974, negative correlation between the QBO and NINO3.4 indices reached its maximum when the NINO3.4 index lagged the QBO by less than 6 months. Correspondingly, the positive correlations were observed when the NINO3.4 index led the QBO by about 11-13 months or lagged by about 12-18 months. However, maximum negative correlations were shifted from the NINO3.4 index lagging the QBO by about 0-6 months during 1966-1974 to about 3-12 months during 1985-1992. During 1975-1979, both the negative and positive correlations were relatively small and the QBO and ENSO were practically unrelated to each other. The phase-based QBO life cycle composites also confirm that, on average, there are two phase (6-7 months) delay in the evolution of the QBO-associated anomalous Walker circulation, tropical SST, atmospheric stability, and troposphere and lower stratosphere temperature anomalies during 1980-1994 in comparison with those in 1957-1978. The interdecadal variation of the association between the QBO and the troposphere variability may be largely due to the characteristic change of El Nino-Southern Oscillation. The irregularity of the QBO may play a secondary role in the interdecadal variation of the association. (orig.)

Response of the global surface ozone distribution to Northern Hemisphere sea surface temperature changes: implications for long-range transport

Science.gov (United States)

Yi, Kan; Liu, Junfeng; Ban-Weiss, George; Zhang, Jiachen; Tao, Wei; Cheng, Yanli; Tao, Shu

2017-07-01

The response of surface ozone (O3) concentrations to basin-scale warming and cooling of Northern Hemisphere oceans is investigated using the Community Earth System Model (CESM). Idealized, spatially uniform sea surface temperature (SST) anomalies of ±1 °C are individually superimposed onto the North Pacific, North Atlantic, and North Indian oceans. Our simulations suggest large seasonal and regional variability in surface O3 in response to SST anomalies, especially in the boreal summer. The responses of surface O3 associated with basin-scale SST warming and cooling have similar magnitude but are opposite in sign. Increasing the SST by 1 °C in one of the oceans generally decreases the surface O3 concentrations from 1 to 5 ppbv. With fixed emissions, SST increases in a specific ocean basin in the Northern Hemisphere tend to increase the summertime surface O3 concentrations over upwind regions, accompanied by a widespread reduction over downwind continents. We implement the integrated process rate (IPR) analysis in CESM and find that meteorological O3 transport in response to SST changes is the key process causing surface O3 perturbations in most cases. During the boreal summer, basin-scale SST warming facilitates the vertical transport of O3 to the surface over upwind regions while significantly reducing the vertical transport over downwind continents. This process, as confirmed by tagged CO-like tracers, indicates a considerable suppression of intercontinental O3 transport due to increased tropospheric stability at lower midlatitudes induced by SST changes. Conversely, the responses of chemical O3 production to regional SST warming can exert positive effects on surface O3 levels over highly polluted continents, except South Asia, where intensified cloud loading in response to North Indian SST warming depresses both the surface air temperature and solar radiation, and thus photochemical O3 production. Our findings indicate a robust linkage between basin-scale SST

Response of the global surface ozone distribution to Northern Hemisphere sea surface temperature changes: implications for long-range transport

Directory of Open Access Journals (Sweden)

K. Yi

2017-07-01

Full Text Available The response of surface ozone (O3 concentrations to basin-scale warming and cooling of Northern Hemisphere oceans is investigated using the Community Earth System Model (CESM. Idealized, spatially uniform sea surface temperature (SST anomalies of ±1 °C are individually superimposed onto the North Pacific, North Atlantic, and North Indian oceans. Our simulations suggest large seasonal and regional variability in surface O3 in response to SST anomalies, especially in the boreal summer. The responses of surface O3 associated with basin-scale SST warming and cooling have similar magnitude but are opposite in sign. Increasing the SST by 1 °C in one of the oceans generally decreases the surface O3 concentrations from 1 to 5 ppbv. With fixed emissions, SST increases in a specific ocean basin in the Northern Hemisphere tend to increase the summertime surface O3 concentrations over upwind regions, accompanied by a widespread reduction over downwind continents. We implement the integrated process rate (IPR analysis in CESM and find that meteorological O3 transport in response to SST changes is the key process causing surface O3 perturbations in most cases. During the boreal summer, basin-scale SST warming facilitates the vertical transport of O3 to the surface over upwind regions while significantly reducing the vertical transport over downwind continents. This process, as confirmed by tagged CO-like tracers, indicates a considerable suppression of intercontinental O3 transport due to increased tropospheric stability at lower midlatitudes induced by SST changes. Conversely, the responses of chemical O3 production to regional SST warming can exert positive effects on surface O3 levels over highly polluted continents, except South Asia, where intensified cloud loading in response to North Indian SST warming depresses both the surface air temperature and solar radiation, and thus photochemical O3 production. Our findings indicate a robust linkage

Identification of the receptors for somatostatin (SST) and cortistatin (CST) in chickens and investigation of the roles of cSST28, cSST14, and cCST14 in inhibiting cGHRH1-27NH2-induced growth hormone secretion in cultured chicken pituitary cells.

Science.gov (United States)

Meng, Fengyan; Huang, Guian; Gao, Shunyu; Li, Juan; Yan, Zhenxin; Wang, Yajun

2014-03-25

Somatostatin receptors (SSTRs) are proposed to mediate the actions of somatostatin (SST) and its related peptide, cortistatin (CST), in vertebrates. However, the identity, functionality, and tissue expression of these receptors remain largely unknown in most non-mammalian vertebrates including birds. In this study, five SSTRs (named cSSTR1, cSSTR2, cSSTR3, cSSTR4, cSSTR5) were cloned from chicken brain by RT-PCR. Using a pGL3-CRE-luciferase reporter system, we demonstrated that activation of each cSSTR expressed in CHO cells by cSST28, cSST14 and cCST14 treatment could inhibit forskolin-induced luciferase activity of CHO cells, indicating the functional coupling of all cSSTRs to Gi protein(s). Interestingly, cSSTR1-4 expressed in CHO cells could be activated by cSST28, cSST14 and cCST14 with high potencies, suggesting that they may function as the receptors common for these peptides. In contrast, cSSTR5 could be potently activated by cSST28 only, indicating that it is a cSST28-specific receptor. Using RT-PCR, wide expression of cSSTRs was detected in chicken tissues including pituitary. In accordance with their expression in pituitary, cSST28, cSST14, and cCST14 were demonstrated to inhibit basal and novel cGHRH1-27NH2-induced GH secretion in cultured chicken pituitary cells dose-dependently (0-10nM) by Western blot analysis, suggesting the involvement of cSSTR(s) common for these peptides in mediating their inhibitory actions. Collectively, our study establishes a molecular basis to elucidate the roles of SST/CST in birds and provide insights into the roles of SST/CST in vertebrates, such as their conserved actions on pituitary. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Support for global climate reorganization during the ''Medieval Climate Anomaly''

Energy Technology Data Exchange (ETDEWEB)

Graham, N.E. [Hydrologic Research Center, San Diego, CA (United States); Scripps Institution of Oceanography, La Jolla, CA (United States); Ammann, C.M. [National Center for Atmospheric Research, Boulder, CO (United States); Fleitmann, D. [University of Bern, Institute of Geological Sciences, Bern (Switzerland); University of Bern, Oeschger Centre for Climatic Change Research, Bern (Switzerland); Cobb, K.M. [Georgia Institute of Technology, Atlanta, GA (United States); Luterbacher, J. [Justus-Liebig-University, Giessen (Germany)

2011-09-15

Widely distributed proxy records indicate that the Medieval Climate Anomaly (MCA; {proportional_to}900-1350 AD) was characterized by coherent shifts in large-scale Northern Hemisphere atmospheric circulation patterns. Although cooler sea surface temperatures in the central and eastern equatorial Pacific can explain some aspects of medieval circulation changes, they are not sufficient to account for other notable features, including widespread aridity through the Eurasian sub-tropics, stronger winter westerlies across the North Atlantic and Western Europe, and shifts in monsoon rainfall patterns across Africa and South Asia. We present results from a full-physics coupled climate model showing that a slight warming of the tropical Indian and western Pacific Oceans relative to the other tropical ocean basins can induce a broad range of the medieval circulation and climate changes indicated by proxy data, including many of those not explained by a cooler tropical Pacific alone. Important aspects of the results resemble those from previous simulations examining the climatic response to the rapid Indian Ocean warming during the late twentieth century, and to results from climate warming simulations - especially in indicating an expansion of the Northern Hemisphere Hadley circulation. Notably, the pattern of tropical Indo-Pacific sea surface temperature (SST) change responsible for producing the proxy-model similarity in our results agrees well with MCA-LIA SST differences obtained in a recent proxy-based climate field reconstruction. Though much remains unclear, our results indicate that the MCA was characterized by an enhanced zonal Indo-Pacific SST gradient with resulting changes in Northern Hemisphere tropical and extra-tropical circulation patterns and hydroclimate regimes, linkages that may explain the coherent regional climate shifts indicated by proxy records from across the planet. The findings provide new perspectives on the nature and possible causes of the MCA

The accuracy of SST retrievals from AATSR: An initial assessment through geophysical validation against in situ radiometers, buoys and other SST data sets

Science.gov (United States)

Corlett, G. K.; Barton, I. J.; Donlon, C. J.; Edwards, M. C.; Good, S. A.; Horrocks, L. A.; Llewellyn-Jones, D. T.; Merchant, C. J.; Minnett, P. J.; Nightingale, T. J.; Noyes, E. J.; O'Carroll, A. G.; Remedios, J. J.; Robinson, I. S.; Saunders, R. W.; Watts, J. G.

The Advanced Along-Track Scanning Radiometer (AATSR) was launched on Envisat in March 2002. The AATSR instrument is designed to retrieve precise and accurate global sea surface temperature (SST) that, combined with the large data set collected from its predecessors, ATSR and ATSR-2, will provide a long term record of SST data that is greater than 15 years. This record can be used for independent monitoring and detection of climate change. The AATSR validation programme has successfully completed its initial phase. The programme involves validation of the AATSR derived SST values using in situ radiometers, in situ buoys and global SST fields from other data sets. The results of the initial programme presented here will demonstrate that the AATSR instrument is currently close to meeting its scientific objectives of determining global SST to an accuracy of 0.3 K (one sigma). For night time data, the analysis gives a warm bias of between +0.04 K (0.28 K) for buoys to +0.06 K (0.20 K) for radiometers, with slightly higher errors observed for day time data, showing warm biases of between +0.02 (0.39 K) for buoys to +0.11 K (0.33 K) for radiometers. They show that the ATSR series of instruments continues to be the world leader in delivering accurate space-based observations of SST, which is a key climate parameter.

The role of the SST-thermocline relationship in Indian Ocean Dipole skewness and its response to global warming

Science.gov (United States)

Ng, Benjamin; Cai, Wenju; Walsh, Kevin

2014-01-01

A positive Indian Ocean Dipole (IOD) tends to have stronger cold sea surface temperature anomalies (SSTAs) over the eastern Indian Ocean with greater impacts than warm SSTAs that occur during its negative phase. Two feedbacks have been suggested as the cause of positive IOD skewness, a positive Bjerknes feedback and a negative SST-cloud-radiation (SCR) feedback, but their relative importance is debated. Using inter-model statistics, we show that the most important process for IOD skewness is an asymmetry in the thermocline feedback, whereby SSTAs respond to thermocline depth anomalies more strongly during the positive phase than negative phase. This asymmetric thermocline feedback drives IOD skewness despite positive IODs receiving greater damping from the SCR feedback. In response to global warming, although the thermocline feedback strengthens, its asymmetry between positive and negative IODs weakens. This behaviour change explains the reduction in IOD skewness that many models display under global warming. PMID:25112717

Western tropical Pacific multidecadal variability forced by the Atlantic multidecadal oscillation

Science.gov (United States)

Kucharski, F.; Sun, C.; Li, J.; Jin, F. F.; Kang, I. S.; Ding, R.

2017-12-01

Observational analysis suggests that the western tropical Pacific (WTP) sea surface temperature (SST) shows predominant variability over multidecadal time scales, which is unlikely to be explained by the Interdecadal Pacific Oscillation. Here we show that this variability is largely explained by the remote Atlantic multidecadal oscillation (AMO). A suite of Atlantic Pacemaker experiments successfully reproduces the WTP multidecadal variability and the AMO-WTP SST connection. The AMO warm SST anomaly generates an atmospheric teleconnection to the North Pacific, which weakens the Aleutian low and subtropical North Pacific westerlies. The wind changes induce a subtropical North Pacific SST warming through wind-evaporation-SST effect, and in response to this warming, the surface winds converge towards the subtropical North Pacific from the tropics, leading to anomalous cyclonic circulation and low pressure over the WTP region. The warm SST anomaly further develops due to the SST-sea level pressure-cloud-longwave radiation positive feedback. Our findings suggest that the Atlantic Ocean acts as a key pacemaker for the western Pacific decadal climate variability.

Optimization design for SST-1 Tokamak insulators

International Nuclear Information System (INIS)

Zhang Yuanbin; Pan Wanjiang

2012-01-01

With the help of ANSYS FEA technique, high voltage and cryogenic proper- ties of the SST-1 Tokamak insulators were obtained, and the structure of the insulators was designed and modified by taking into account the simulation results. The simulation results indicate that the optimization structure has better high voltage insulating property and cryogenic mechanics property, and also can fulfill the qualification criteria of the SST-1 Tokamak insulators. (authors)

Preliminary analysis of accident in SST-1 current feeder system

International Nuclear Information System (INIS)

Roy, Swati; Kanabar, Deven; Garg, Atul; Singh, Amit; Tanna, Vipul; Prasad, Upendra; Srinivasan, R.

2017-01-01

Steady-state Tokamak-1 (SST-1) has 16 superconducting Toroidal field (TF) and 9 superconducting poloidal field (PF) coils rated for 10kA DC. All the TF are connected in series and are operated in DC condition whereas PF coils are individually operated in pulse mode during SST-1 campaigns. SST-1 current feeder system (CFS) houses 9 pairs of PF current leads and 1 pair of TF current leads. During past SST-1 campaign, there were arcing incidents within SST-1 CFS chamber which caused significant damage to PF superconducting current leads as well as its Helium cooling lines of the current leads. This paper brings out the preliminary analysis of the mentioned arcing incident, possible reasons and its investigation thereby laying out the sequence of events. From this analysis and observations, various measures to avoid such arcing incidents have also been proposed. (author)

The TaSST: Tactile Sleeve for Social Touch

NARCIS (Netherlands)

Huisman, G.; Darriba Frederiks, A.; van Dijk, B.; Heylen, D.; Kröse, B.

2013-01-01

In this paper we outline the design process of the TaSST (Tactile Sleeve for Social Touch), a touch-sensitive vibrotactile arm sleeve. The TaSST was designed to enable two people to communicate different types of touch over a distance. The touch-sensitive surface of the sleeve consists of a grid of

The TaSST: Tactile sleeve for social touch

NARCIS (Netherlands)

Huisman, Gijs; Darriba Frederiks, Aduén; van Dijk, Elisabeth M.A.G.; Heylen, Dirk K.J.; Krose, Ben

In this paper we outline the design process of the TaSST (Tactile Sleeve for Social Touch), a touch-sensitive vibrotactile arm sleeve. The TaSST was designed to enable two people to communicate different types of touch over a distance. The touch-sensitive surface of the sleeve consists of a grid of

The TaSST - Tactile Sleeve for Social Touch

NARCIS (Netherlands)

Huisman, Gijs; Darriba Frederiks, Aduén; Van Dijk, Betsy; Heylen, Dirk

2013-01-01

In this paper we outline the design process of TaSST (Tactile Sleeve for Social Touch), a touch-sensitive vibrotactile arm sleeve. The TaSST was designed to enable two people to communicate different types of touches over a distance. The touch-sensitive surface of the sleeve consists of a grid of

Variability and Predictability of West African Droughts. A Review in the Role of Sea Surface Temperature Anomalies

Science.gov (United States)

Rodriguez-Fonseca, Belen; Mohino, Elsa; Mechoso, Carlos R.; Caminade, Cyril; Biasutti, Michela; Gaetani, Marco; Garcia-Serrano, J.; Vizy, Edward K.; Cook, Kerry; Xue, Yongkang;

Seasonal anomalies in electricity intensity across Chinese regions

International Nuclear Information System (INIS)

Herrerias, M.J.

2013-01-01

Highlights: ► We analyze seasonal anomalies in electricity intensity in China. ► Regional and time dimensions are investigated from 2003 to 2009. ► Results suggest that seasonality is stochastic. ► We find four main effects: Summer, Winter, Spring and Lunar New Year effects. ► Differences are observed between northern regions and east-south of China. - Abstract: This paper provides evidence on the relevance of modeling the seasonal nature of electricity intensity across Chinese regions in a suitable manner with monthly data from 2003 to 2009. In contrast to previous works, this study relaxes the assumption of deterministic seasonality, allowing for time and regional variation in the Chinese economy. In doing so, unobserved-components models are used to analyze the type of seasonality – stochastic or deterministic – that prevails. Regional differences in the seasonal patterns and their evolution over time are also examined. Results provide new empirical evidence on the stochastic nature of electricity intensity in the majority of the provinces. In addition, we find four main effects as regards seasonal patterns: (i) Lunar New Year, (ii) Summer, (iii) Spring, and (iv) Winter effects. In the first two effects seasonality becomes positive, thus indicating that electricity intensity increases, and the last two are negative, showing improvements in the use of electricity per unit of output. However, differences are observed between northern regions and the east-south of China. In addition, once we control our estimates for temperature and prices, no significant differences are seen in the results. Conclusions from this analysis are useful for empirical modeling in the energy-economics literature, and also for designing energy policies to improve the efficiency of the use of energy resources across Chinese regions

Occurrence and multivariate exploratory analysis of the natural radioactivity anomaly in the south coastal region of Kenya

Science.gov (United States)

Kaniu, M. I.; Angeyo, K. H.; Darby, I. G.

2018-05-01

Characterized by a variety of rock formations, namely alkaline, igneous and sedimentary that contain significant deposits of monazite and pyrochlore ores, the south coastal region of Kenya may be regarded as highly heterogeneous with regard to its geochemistry, mineralogy as well as geological morphology. The region is one of the several alkaline carbonatite complexes of Kenya that are associated with high natural background radiation and therefore radioactivity anomaly. However, this high background radiation (HBR) anomaly has hardly been systematically assessed and delineated with regard to the spatial, geological, geochemical as well as anthropogenic variability and co-dependencies. We conducted wide-ranging in-situ gamma-ray spectrometric measurements in this area. The goal of the study was to assess the radiation exposure as well as determine the underlying natural radioactivity levels in the region. In this paper we report the occurrence, exploratory analysis and modeling to assess the multivariate geo-dependence and spatial variability of the radioactivity and associated radiation exposure. Unsupervised principal component analysis and ternary plots were utilized in the study. It was observed that areas which exhibit HBR anomalies are located along the south coast paved road and in the Mrima-Kiruku complex. These areas showed a trend towards enhanced levels of 232Th and 238U and low 40K. The spatial variability of the radioactivity anomaly was found to be mainly constrained by anthropogenic activities, underlying geology and geochemical processes in the terrestrial environment.

Novel sst2-selective somatostatin agonists. Three-dimensional consensus structure by NMR

Science.gov (United States)

Grace, Christy Rani R.; Erchegyi, Judit; Koerber, Steven C.; Reubi, Jean Claude; Rivier, Jean; Riek, Roland

2008-01-01

The three-dimensional NMR structures of six octapeptide agonist analogues of somatostatin (SRIF) in the free form are described. These analogues, with the basic sequence H-DPhe/Phe2-c[Cys3-Xxx7-DTrp8-Lys9-Thr10-Cys14]-Thr-NH2 (the numbering refers to the position in native SRIF), with Xxx7 being Ala/Aph, exhibit potent and highly selective binding to human SRIF type 2 (sst2) receptors. The backbone of these sst2-selective analogues have the usual type-II’ β-turn reported in the literature for sst2/3/5-subtype-selective analogues. Correlating biological results and NMR studies led to the identification of the side chains of DPhe2, DTrp8 and Lys9 as the necessary components of the sst2 pharmacophore. This is the first study to show that the aromatic ring at position 7 (Phe7) is not critical for sst2 binding and that it plays an important role in sst3 and sst5 binding. This pharmacophore is therefore different from that proposed by others for sst2/3/5 analogues. PMID:16854054

Atmosphere-Ocean Variations in the Indo-Pacific Sector during ENSO Episodes.

Science.gov (United States)

Lau, Ngar-Cheung; Nath, Mary Jo

2003-01-01

The influences of El Niño-Southern Oscillation (ENSO) events on air-sea interaction in the Indian-western Pacific (IWP) Oceans have been investigated using a general circulation model. Observed monthly sea surface temperature (SST) variations in the deep tropical eastern/central Pacific (DTEP) have been inserted in the lower boundary of this model through the 1950-99 period. At all maritime grid points outside of DTEP, the model atmosphere has been coupled with an oceanic mixed layer model with variable depth. Altogether 16 independent model runs have been conducted.Composite analysis of selected ENSO episodes illustrates that the prescribed SST anomalies in DTEP affect the surface atmospheric circulation and precipitation patterns in IWP through displacements of the near-equatorial Walker circulation and generation of Rossby wave modes in the subtropics. Such atmospheric responses modulate the surface fluxes as well as the oceanic mixed layer depth, and thereby establish a well-defined SST anomaly pattern in the IWP sector several months after the peak in ENSO forcing in DTEP. In most parts of the IWP region, the net SST tendency induced by atmospheric changes has the same polarity as the local composite SST anomaly, thus indicating that the atmospheric forcing acts to reinforce the underlying SST signal.By analyzing the output from a suite of auxiliary experiments, it is demonstrated that the SST perturbations in IWP (which are primarily generated by ENSO-related atmospheric changes) can, in turn, exert notable influences on the atmospheric conditions over that region. This feedback mechanism also plays an important role in the eastward migration of the subtropical anticyclones over the western Pacific in both hemispheres.

Tropical Atlantic Hurricanes, Easterly Waves, and West African Mesoscale Convective Systems

Directory of Open Access Journals (Sweden)

Yves K. Kouadio

2010-01-01

Full Text Available The relationship between tropical Atlantic hurricanes (Hs, atmospheric easterly waves (AEWs, and West African mesoscale convective systems (MCSs is investigated. It points out atmospheric conditions over West Africa before hurricane formation. The analysis was performed for two periods, June–November in 2004 and 2005, during which 12 hurricanes (seven in 2004, five in 2005 were selected. Using the AEW signature in the 700 hPa vorticity, a backward trajectory was performed to the African coast, starting from the date and position of each hurricane, when and where it was catalogued as a tropical depression. At this step, using the Meteosat-7 satellite dataset, we selected all the MCSs around this time and region, and tracked them from their initiation until their dissipation. This procedure allowed us to relate each of the selected Hs with AEWs and a succession of MCSs that occurred a few times over West Africa before initiation of the hurricane. Finally, a dipole in sea surface temperature (SST was observed with a positive SST anomaly within the region of H generation and a negative SST anomaly within the Gulf of Guinea. This SST anomaly dipole could contribute to enhance the continental convergence associated with the monsoon that impacts on the West African MCSs formation.

Predicting summer monsoon of Bhutan based on SST and teleconnection indices

Science.gov (United States)

Dorji, Singay; Herath, Srikantha; Mishra, Binaya Kumar; Chophel, Ugyen

2018-02-01

The paper uses a statistical method of predicting summer monsoon over Bhutan using the ocean-atmospheric circulation variables of sea surface temperature (SST), mean sea-level pressure (MSLP), and selected teleconnection indices. The predictors are selected based on the correlation. They are the SST and MSLP of the Bay of Bengal and the Arabian Sea and the MSLP of Bangladesh and northeast India. The Northern Hemisphere teleconnections of East Atlantic Pattern (EA), West Pacific Pattern (WP), Pacific/North American Pattern, and East Atlantic/West Russia Pattern (EA/WR). The rainfall station data are grouped into two regions with principal components analysis and Ward's hierarchical clustering algorithm. A support vector machine for regression model is proposed to predict the monsoon. The model shows improved skills over traditional linear regression. The model was able to predict the summer monsoon for the test data from 2011 to 2015 with a total monthly root mean squared error of 112 mm for region A and 33 mm for region B. Model could also forecast the 2016 monsoon of the South Asia Monsoon Outlook of World Meteorological Organization (WMO) for Bhutan. The reliance on agriculture and hydropower economy makes the prediction of summer monsoon highly valuable information for farmers and various other sectors. The proposed method can predict summer monsoon for operational forecasting.

The Coral Reef Temperature Anomaly Database (CoRTAD) Version 4 - Global, 4 km Sea Surface Temperature and Related Thermal Stress Metrics for 1981-10-31 to 2010-12-31 (NODC Accession 0087989)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Coral Reef Temperature Anomaly Database (CoRTAD) is a collection of sea surface temperature (SST) and related thermal stress metrics, developed specifically for...

Indian Ocean Dipole and El Niño/Southern Oscillation impacts on regional chlorophyll anomalies in the Indian Ocean

Directory of Open Access Journals (Sweden)

J. C. Currie

2013-10-01

Full Text Available The Indian Ocean Dipole (IOD and the El Niño/Southern Oscillation (ENSO are independent climate modes, which frequently co-occur, driving significant interannual changes within the Indian Ocean. We use a four-decade hindcast from a coupled biophysical ocean general circulation model, to disentangle patterns of chlorophyll anomalies driven by these two climate modes. Comparisons with remotely sensed records show that the simulation competently reproduces the chlorophyll seasonal cycle, as well as open-ocean anomalies during the 1997/1998 ENSO and IOD event. Results suggest that anomalous surface and euphotic-layer chlorophyll blooms in the eastern equatorial Indian Ocean in fall, and southern Bay of Bengal in winter, are primarily related to IOD forcing. A negative influence of IOD on chlorophyll concentrations is shown in a region around the southern tip of India in fall. IOD also depresses depth-integrated chlorophyll in the 5–10° S thermocline ridge region, yet the signal is negligible in surface chlorophyll. The only investigated region where ENSO has a greater influence on chlorophyll than does IOD, is in the Somalia upwelling region, where it causes a decrease in fall and winter chlorophyll by reducing local upwelling winds. Yet unlike most other regions examined, the combined explanatory power of IOD and ENSO in predicting depth-integrated chlorophyll anomalies is relatively low in this region, suggestive that other drivers are important there. We show that the chlorophyll impact of climate indices is frequently asymmetric, with a general tendency for larger positive than negative chlorophyll anomalies. Our results suggest that ENSO and IOD cause significant and predictable regional re-organisation of chlorophyll via their influence on near-surface oceanography. Resolving the details of these effects should improve our understanding, and eventually gain predictability, of interannual changes in Indian Ocean productivity, fisheries

A 1200 Year Alkenone-based Reconstruction of Sea Surface Temperature and Marine Productivity in the Southern California Current System from the Medieval Climate Anomaly to Present

Science.gov (United States)

O'Mara, N. A.; Kelly, C. S.; Herbert, T.

2017-12-01

Laminated sediment cores taken from the San Lazaro Basin (SLB) (25.18N, 112.66W) located off the coast of Baja California in the subtropical eastern Pacific were geochemically analyzed for alkenone and sterol biomarkers to reconstruct sea surface temperature (SST) and marine productivity from 850-1980 CE. High sedimentation rates, low bottom water dissolved oxygen, and high marine productivity in combination with the San Lazaro Basin's location within the dynamic transition zone between the tropical and subtropical eastern Pacific, make it a prime location to study variability of tropical and subtropical modes of climate variability. This study focuses on the impacts and variability of the El Niño Southern Oscillation and the Pacific Decadal Oscillation on the subtropical eastern Pacific. SST and coccolithophore productivity (n=730) for 2 mm sections of sediment corresponding to 1 measurement every 1.8 years were reconstructed using the Uk'37 unsaturation index and C37 alkenone concentration. The high resolution of this record allowed for the analysis of variability of SST and productivity on decadal timescales. Brassicasterol concentrations were calculated for a limited number of samples (n=44) to assess diatom productivity. High spectral power was found at periods of 20-30 years in SST and productivity records indicating a strong influence of the PDO on the SLB, making this the first marine based record directly relevant to PDO reconstructions that continuously spans the last millennium. Cool and productive (warm and less productive) waters were observed in the southern California Current in the Medieval Climate Anomaly 900-1200 CE (Little Ice Age 1400-1800 CE) supporting previous reconstructions that warmer (cooler) SST are linked to both reduced (enhanced) phytoplankton productivity. Additionally, cool (warm) SST were also associated with dry (wet) conditions in the American Southwest indicating that changes in the PDO has had a significant impact on drought

Quench detection electronics testing protocol for SST-1 magnets

International Nuclear Information System (INIS)

Banaudha, Moni; Varmora, Pankaj; Parghi, Bhadresh; Prasad, Upendra

2017-01-01

Quench Detection (QD) system consisting 204 signal channels has been successfully installed and working well during plasma experiment of SST-1 Tokamak. QD system requires testing, validation and maintenance in every SST-1 campaign for better reliability and maintainability of the system. Standalone test of each channel of the system is essential for hard-ware validation. The standard Testing Protocol follow in every campaign which validate each section of QD electronics as well as voltage tap signal cables which are routed inside the cryostat and then extended outside of the SST-1 machine up-to the magnet control room. Fiber link for Quench signal transmission to the SST-1 magnet power supply is also test and validate before every plasma campaign. Precise instrument used as a dummy source of quench signal and for manual quench generation to test the each channel and Master Quench Logic. Each signal Integrated with the magnet DAQ system, signal observed at 1Hz and 50Hz configuration to validate the logging data, compare with actual and previous test data. This paper describes the testing protocol follow in every campaign to validate functionality of QD electronics, limitation of testing, test results and overall integration of the quench detection system for SST-1 magnet. (author)

Genotype-Phenotype Relationship in Patients and Relatives with SHOX Region Anomalies in the French Population.

Science.gov (United States)

Auger, Julie; Baptiste, Amandine; Benabbad, Imane; Thierry, Gaëlle; Costa, Jean-Marc; Amouyal, Mélanie; Kottler, Marie-Laure; Leheup, Bruno; Touraine, Renaud; Schmitt, Sébastien; Lebrun, Marine; Cormier Daire, Valérie; Bonnefont, Jean-Paul; de Roux, Nicolas; Elie, Caroline; Rosilio, Myriam

2016-01-01

The aim of our study was to describe a large population with anomalies involving the SHOX region, responsible for idiopathic short stature and Léri-Weill dyschondrosteosis (LWD), and to identify a possible genotype/phenotype correlation. We performed a retrospective multicenter study on French subjects with a SHOX region anomaly diagnosed by multiplex ligation-dependent probe amplification or Sanger sequencing. Phenotypes were collected in each of the 7 genetic laboratories practicing this technique for SHOX analysis. Among 205 index cases and 100 related cases, 91.3% had LWD. For index cases, median age at evaluation was 11.7 (9.0; 15.9) years and mean height standard deviation score was -2.3 ± 1.1. A deletion of either SHOX or PAR1 or both was found in 74% of patients. Duplications and point mutations/indels affected 8 and 18% of the population, respectively. Genotype-phenotype correlation showed that deletions were more frequently associated with Madelung deformity and mesomelic shortening in girls, as well as with presence of radiologic anomalies, than duplications. Our results highlight genotype-phenotype relationships in the French population with a SHOX defect and provide new information showing that clinical expression is milder in cases of duplication compared to deletions. © 2016 S. Karger AG, Basel.

The possible physical mechanism for the EAP–SR co-action

KAUST Repository

Gong, Zhiqiang

2017-11-17

The anomalous characteristics of summer precipitation and atmospheric circulation in the East Asia–West Pacific Region (EA–WP) associated with the co-action of East Asia/Pacific teleconnection–Silk Road teleconnection (EAP–SR) are investigated in this study. The compositions of EAP–SR phase anomalies can be expressed as pattern I (+ +), pattern II (+ −), pattern III (− −), and pattern IV (− +) using EAP and SR indices. It is found that the spatial distribution of summer precipitation anomalies in EA–WP corresponding to pattern I (III) shows a tripole structure in the meridional direction and a zonal dipole structure in the subtropical region, while pattern II (IV) presents a tripole pattern in meridional direction with compressed and continuous anomalies in the zonal direction over the subtropical region. The similar meridional and zonal structures are also found in the geopotential height anomalies at 500-hPa, as well as wind anomalies and moisture convergence at 850-hPa. Finally, a schematic mechanism for the EAP–SR co-action upon the summer precipitation in EA–WP is built: (1) Pattern I (III) exhibits that the negative (positive) sea surface temperature (SST) anomalies over tropical East Pacific may cause the enhanced (weakened) convective activity dominating the West Pacific, trigger the positive (negative) EAP teleconnection and produce more (less) precipitation. Besides, the negative (positive) SST anomalies over the Indonesia Maritime Continent (IMC) may further weaken (strengthen) anomalous downward (upward) motion over the South China Sea (SCS), cause negative (positive) geopotential height anomalies at the middle troposphere and surrounding regions through the function of the tropical Hadley circulation. Then the negative (positive) geopotential height anomalies could motivate the positive (negative) EAP teleconnection through the northward propagation of wave-activity perturbation. Meanwhile, a positive (negative) geopotential

The possible physical mechanism for the EAP-SR co-action

Science.gov (United States)

Gong, Zhiqiang; Feng, Guolin; Dogar, Muhammad Mubashar; Huang, Gang

2017-11-01

The anomalous characteristics of summer precipitation and atmospheric circulation in the East Asia-West Pacific Region (EA-WP) associated with the co-action of East Asia/Pacific teleconnection-Silk Road teleconnection (EAP-SR) are investigated in this study. The compositions of EAP-SR phase anomalies can be expressed as pattern I (+ +), pattern II (+ -), pattern III (- -), and pattern IV (- +) using EAP and SR indices. It is found that the spatial distribution of summer precipitation anomalies in EA-WP corresponding to pattern I (III) shows a tripole structure in the meridional direction and a zonal dipole structure in the subtropical region, while pattern II (IV) presents a tripole pattern in meridional direction with compressed and continuous anomalies in the zonal direction over the subtropical region. The similar meridional and zonal structures are also found in the geopotential height anomalies at 500-hPa, as well as wind anomalies and moisture convergence at 850-hPa. Finally, a schematic mechanism for the EAP-SR co-action upon the summer precipitation in EA-WP is built: (1) Pattern I (III) exhibits that the negative (positive) sea surface temperature (SST) anomalies over tropical East Pacific may cause the enhanced (weakened) convective activity dominating the West Pacific, trigger the positive (negative) EAP teleconnection and produce more (less) precipitation. Besides, the negative (positive) SST anomalies over the Indonesia Maritime Continent (IMC) may further weaken (strengthen) anomalous downward (upward) motion over the South China Sea (SCS), cause negative (positive) geopotential height anomalies at the middle troposphere and surrounding regions through the function of the tropical Hadley circulation. Then the negative (positive) geopotential height anomalies could motivate the positive (negative) EAP teleconnection through the northward propagation of wave-activity perturbation. Meanwhile, a positive (negative) geopotential height anomalous pattern

Sea surface temperature anomalies in the Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

RameshKumar, M.R.

temperature anomalies for the above regions respectively. An analysis has shown that most of the short duration anomalies (i.e., anomalies with periods less than 4 months) are driven by the surface heat fluxes. The medium duration anomalies (i.e., anomalies...

An overview of SST-1 diagnostics and results from recent campaigns

International Nuclear Information System (INIS)

Kumar, Ajai; Adhiya, Asha N.; Joshi, Hemchandra C.

2015-01-01

SST-1 is a large aspect ratio tokomak with superconducting magnets designed to operate in steady-state mode for around 1000 seconds. All essential diagnostics for the machine operation and advance diagnostics are commissioned in SST-1 during the different phases of its operation. This report describes the various diagnostics in SST-1 and the results of recent SST-1 campaign with Plasma Facing components. The chord averaged electron density of SST-1 plasma is recorded in the range of 2-5 x 10 12 /cc and the electron temperature is estimated around 100 eV. Various spectral line emissions from plasma and temporal evolutions of some of them have been recorded by spectroscopy diagnostics to understand the impurity behaviour in the SST-1 plasma. The radiation power loss and the power deposited on limiter has been estimated using bolometry and IR thermography respectively. Plasma evolution recorded using visible imaging diagnostics. The energy distribution of non-thermal electron has been characterised using LaBr spectrometer and NaI detector. This article will also be discussing about the possible additions and modification planned for the near future. (author)

GHRSST Level 2P European Medspiration NAR16 SST:1

Data.gov (United States)

National Aeronautics and Space Administration — The EUMETSAT OSI-SAF NAR SST products are SST fields derived from NOAA/AVHRR data and available over 6 pre-defined zones, 4 times per day. After acquisition and...

GHRSST Level 2P European Medspiration NAR18 SST:1

Data.gov (United States)

National Aeronautics and Space Administration — The EUMETSAT OSI-SAF NAR SST products are SST fields derived from NOAA/AVHRR data and available over 6 pre-defined zones, 4 times per day. After acquisition and...

GHRSST Level 2P European Medspiration NAR17 SST:1

Data.gov (United States)

National Aeronautics and Space Administration — The EUMETSAT OSI-SAF NAR SST products are SST fields derived from NOAA/AVHRR data and available over 6 pre-defined zones, 4 times per day. After acquisition and...

An assessment of TropFlux and NCEP air-sea fluxes on ROMS simulations over the Bay of Bengal region

Science.gov (United States)

Dey, Dipanjan; Sil, Sourav; Jana, Sudip; Pramanik, Saikat; Pandey, P. C.

2017-12-01

This study presents an assessment of the TropFlux and the National Centers for Environmental Prediction (NCEP) reanalysis air-sea fluxes in simulating the surface and subsurface oceanic parameters over the Bay of Bengal (BoB) region during 2002-2014 using the Regional Ocean Modelling System (ROMS). The assessment has been made by comparing the simulated fields with in-situ and satellite observations. The simulated surface and subsurface temperatures in the TropFlux forced experiment (TropFlux-E) show better agreement with the Research Moored Array for African-Asian-Australian Monsoon Analysis (RAMA) and Argo observations than the NCEP forced experiment (NCEP-E). The BoB domain averaged sea surface temperature (SST) simulated in the NCEP-E is consistently cooler than the satellite SST, with a root mean square error (RMSE) of 0.79 °C. Moreover, NCEP-E shows a limitation in simulating the observed seasonal cycle of the SST due to substantial underestimation of the pre-monsoon SST peak. These limitations are mostly due to the lower values of the NCEP net heat flux. The seasonal and interannual variations of SST in the TropFlux-E are better comparable to the observations with correlations and skills more than 0.80 and 0.90 respectively. However, SST is overestimated during summer monsoon periods mainly due to higher net heat flux. The superiority of TropFlux forcing over the NCEP reanalysis can also be seen when simulating the interannual variabilities of the magnitude and vertical extent of Wyrtki jets at two equatorial RAMA buoy locations. The jet is weaker in the NCEP-E relative to the TropFlux-E and observations. The simulated sea surface height anomalies (SSHA) from both the experiments are able to capture the regions of positive and negative SSHA with respect to satellite-derived altimeter data with better performance in the TropFlux-E. The speed of the westward propagating Rossby wave along 18°N in the TropFlux-E is found to be about 4.7 cm/s, which is close to

The Prevalence of Dental Anomalies in the Western Region of Saudi Arabia

OpenAIRE

Afify, Ahmed R.; Zawawi, Khalid H.

2012-01-01

Objective. The aim of this cross-sectional study was to investigate the prevalence of dental anomalies that could be a cause of malocclusion in the western region of Saudi Arabia. Materials and Methods. A retrospective study of 878 digital orthopantomograms (OPGs) taken of patients, age ranging between 12 and 30 years, who presented to treatment at the Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia between 2002 and 2011. The OPGs and dental records were reviewed for con...

Mechanisms controlling the intra-annual mesoscale variability of SST and SPM in the southern North Sea

Science.gov (United States)

Pietrzak, Julie D.; de Boer, Gerben J.; Eleveld, Marieke A.

2011-04-01

Thermal and optical remote sensing data were used to investigate the spatial and temporal distribution of sea surface temperature (SST) and of suspended particulate matter (SPM) in the southern North Sea. Monthly SST composites showed pronounced seasonal warming of the southern North Sea and delineated the English coastal and continental coastal waters. The East-Anglia Plume is the dominant feature of the English coastal waters in the winter and autumn SPM composites, and the Rhine region of freshwater influence (ROFI), including the Flemish Banks, is the dominant feature of the continental waters. These mesoscale spatial structures are also influenced by the evolution of fronts, such as the seasonal front separating well-mixed water in the southern Bight, from the seasonally stratified central North Sea waters. A harmonic analysis of the SST and SPM images showed pronounced seasonal variability, as well as spring-neap variations in the level of tidal mixing in the East Anglia Plume, the Rhine ROFI and central North Sea. The harmonic analysis indicates the important role played by the local meteorology and tides in governing the SST and near-surface SPM concentrations in the southern North Sea. In the summer, thermal stratification affects the visibility of SPM to satellite sensors in the waters to the north of the Flamborough and Frisian Fronts. Haline stratification plays an important role in the visibility of SPM in the Rhine ROFI throughout the year. When stratified, both regions typically exhibit low surface SPM values. A numerical model study, together with the harmonic analysis, highlights the importance of tides and waves in controlling the stratification in the southern North Sea and hence the visibility of SPM.

Tasmaloum, Vanuatu Fossil Coral SST Reconstruction for 4200 YrBP

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Vanuatu Fossil Coral SST Reconstruction, 4200 YrBP. Paleobathymetry estimated at 10-15 m. SST reconstruction is based on the analysis of Sr/Ca and U/Ca ratios in...

First experiments with SST-1 tokamak

International Nuclear Information System (INIS)

Saxena, Y.C.

2005-01-01

SST-1, a steady state superconducting tokamak, is undergoing commissioning tests at the Institute for Plasma Research. The objectives of SST-1 include studying the physics of the plasma processes in a tokamak under steady state conditions and learning technologies related to the steady state operation of the tokamak. These studies are expected to contribute to the tokamak physics database for very long pulse operations. Superconducting (SC) magnets are deployed for both the toroidal and poloidal field coils in SST-1. An Ohmic transformer is provided for plasma breakdown and initial current ramp up. SST-1 deploys a fully welded ultra high vacuum vessel. Liquid nitrogen cooled radiation shield are deployed between the vacuum vessel and SC magnets as well as SC magnets and cryostat, to minimize the radiation losses at the SC magnets. The auxiliary current drive is based on 1.0 MW of Lower Hybrid current drive (LHCD) at 3.7 GHz. Auxiliary heating systems include 1 MW of Ion Cyclotron Resonance Frequency system (ICRF) at 22 MHz to 91 MHz, 0.2 MW of Electron Cyclotron Resonance heating at 84 GHz and a Neutral Beam Injection (NBI) system with peak power of 0.8 MW (at 80 keV) with variable beam energy in range of 10-80 keV. The ICRF system would also be used for initial breakdown and wall conditioning experiments. Detailed commissioning tests on the cryogenic system and experiments on the hydraulic characters and cool down features of single TF coils have been completed prior to the cool down of the entire superconducting system. Results of the single TF magnet cool down, and testing of the magnet system are presented. First experiments related to the breakdown and the current ramp up will subsequently be carried out. (author)

Overall behaviour of PFC integrated SST-1 vacuum system

Science.gov (United States)

Khan, Ziauddin; Raval, Dilip C.; Paravasu, Yuvakiran; Semwal, Pratibha; Dhanani, Kalpeshkumar R.; George, Siju; Shoaib, Mohammad; Prakash, Arun; Babu, Gattu R.; Thankey, Prashant; Pathan, Firozkhan S.; Pradhan, Subrata

2017-04-01

As a part of phase-I up-gradation of Steady-state Superconducting Tokamak (SST-1), Graphite Plasma Facing Components (PFCs) have been integrated inside SST-1 vacuum vessel as a first wall (FW) during Nov 14 and May 2015. The SST-1 FW has a total surface area of the installed PFCs exposed to plasma is ∼ 40 m2 which is nearly 50% of the total surface area of stainless steel vacuum chamber (∼75 m2). The volume of the vessel within the PFCs is ∼ 16 m3. After the integration of PFCs, the entire vessel as well as the PFC cooling/baking circuits has been qualified with an integrated helium leak tightness of baked at 250 °C for nearly 20 hours employing hot nitrogen gas to remove the absorbed water vapours. Thereafter, Helium glow discharges cleaning were carried out towards the removal of surface impurities. The pump down characteristics of SST-1 vacuum chamber and the changes in the residual gaseous impurities after the installation of the PFCs will be discussed in this paper.

The effect of scale on the interpretation of geochemical anomalies

Science.gov (United States)

Theobald, P.K.; Eppinger, R.G.; Turner, R.L.; Shiquan, S.

1991-01-01

The purpose of geochemical surveys changes with scale. Regional surveys identify areas where mineral deposits are most likely to occur, whereas intermediate surveys identify and prioritize specific targets. At detailed scales specific deposit models may be applied and deposits delineated. The interpretation of regional geochemical surveys must take into account scale-dependent difference in the nature and objectives of this type of survey. Overinterpretation of regional data should be resisted, as should recommendations to restrict intermediate or detailed follow-up surveys to the search for specific deposit types or to a too limited suite of elements. Regional surveys identify metallogenic provinces within which a variety of deposit types and metals are most likely to be found. At intermediate scale, these regional provinces often dissipate into discrete clusters of anomalous areas. At detailed scale, individual anomalous areas reflect local conditions of mineralization and may seem unrelated to each other. Four examples from arid environments illustrate the dramatic change in patterns of anomalies between regional and more detailed surveys. On the Arabian Shield, a broad regional anomaly reflects the distribution of highly differentiated anorogenic granites. A particularly prominent part of the regional anomaly includes, in addition to the usual elements related to the granites, the assemblage of Mo, W and Sn. Initial interpretation suggested potential for granite-related, stockwork Mo deposits. Detailed work identified three separate sources for the anomaly: a metal-rich granite, a silicified and stockwork-veined area with scheelite and molybdenite, and scheelite/powellite concentrations in skarn deposits adjacent to a ring-dike complex. Regional geochemical, geophysical and remote-sensing data in the Sonoran Desert, Mexico, define a series of linear features interpreted to reflect fundamental, northeast-trending fractures in the crust that served as the prime

Asymmetric Response of the Equatorial Pacific SST to Climate Warming and Cooling

Energy Technology Data Exchange (ETDEWEB)

Liu, Fukai [Physical Oceanography Laboratory/Qingdao Collaborative Innovation Center of Marine Science and Technology, Ocean University of China, and Qingdao National Laboratory for Marine Science and Technology, Qingdao, China; Luo, Yiyong [Physical Oceanography Laboratory/Qingdao Collaborative Innovation Center of Marine Science and Technology, Ocean University of China, and Qingdao National Laboratory for Marine Science and Technology, Qingdao, China; Lu, Jian [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington; Garuba, Oluwayemi [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington; Wan, Xiuquan [Physical Oceanography Laboratory/Qingdao Collaborative Innovation Center of Marine Science and Technology, Ocean University of China, and Qingdao National Laboratory for Marine Science and Technology, Qingdao, China

2017-09-01

The response of the equatorial Pacific Ocean to heat fluxes of equal amplitude but opposite sign is investigated using the Community Earth System Model (CESM). Results show a strong asymmetry in SST changes. In the eastern equatorial Pacific (EEP), the warming responding to the positive forcing exceeds the cooling to the negative forcing; while in the western equatorial Pacific (WEP), it is the other way around and the cooling surpasses the warming. This leads to a zonal dipole asymmetric structure, with positive values in the east and negative values in the west. A surface heat budget analysis suggests that the SST asymmetry is mainly resulted from the oceanic horizontal advection and vertical entrainment, with both of their linear and nonlinear components playing a role. For the linear component, its change appears to be more significant over the EEP (WEP) in the positive (negative) forcing scenario, favoring the seesaw pattern of the SST asymmetry. For the nonlinear component, its change acts to warm (cool) the EEP (WEP) in both scenarios, also favorable for the development of the SST asymmetry. Additional experiments with a slab ocean confirm the dominant role of ocean dynamical processes for this SST asymmetry. The net surface heat flux, in contrast, works to reduce the SST asymmetry through its shortwave radiation and latent heat flux components, with the former being related to the nonlinear relationship between SST and convection, and the latter being attributable to Newtonian damping and air-sea stability effects. The suppressing effect of shortwave radiation on SST asymmetry is further verified by partially coupled overriding experiments.

Engineering design and thermal hydraulics of plasma facing components of SST-1

International Nuclear Information System (INIS)

Pragash, N. Ravi; Chaudhuri, P.; Santra, P.; Chenna Reddy, D.; Khirwadkar, S.; Saxena, Y.C.

2001-01-01

SST-1 is a medium size tokamak with super conducting magnetic field coils. All the subsystems of SST-1 are designed for quasi steady state (∼1000 s) operation. Plasma Facing Components (PFCs) of SST-1 consisting of divertors, passive stabilizers, baffles and poloidal limiters are also designed to be compatible for steady state operation. As SST-1 is designed to run double null divertor plasmas, these components also have up-down symmetry. A closed divertor configuration is chosen to produce high recycling and high pumping speed in the divertor region. All the PFC are made of copper alloys (CuCrZr and CuZr) on which graphite tiles are mechanically attached. These copper alloy back plates are actively cooled with water flowing in the channels grooved on them with the main consideration in the design of PFCs as the steady state heat removal of about 1.0 MW/m 2 . In addition to be able to remove high heat fluxes, the PFCs are also designed to be compatible for baking at 350 degree sign C. Extensive studies, involving different flow parameters and various cooling layouts, have been done to select the final cooling parameters and layout. Thermal response of the PFCs and vacuum vessel during baking, has been calculated using a FORTRAN code and a 2-D finite element analysis. The PFCs and their supports are also designed to withstand large electro-magnetic forces. Finite element analysis using ANSYS software package is used in this and other PFCs design. The engineering design including thermal hydraulics for cooling and baking of all the PFCs is completed. Poloidal limiters are being fabricated. The remaining PFCs, viz. divertors, stabilizers and baffles are likely to go for fabrication in the next few months. The detailed engineering design, the finite element calculations in the structural and thermal designs are presented in this paper

AVHRR GAC SST Reanalysis Version 1 (RAN1

Directory of Open Access Journals (Sweden)

Alexander Ignatov

2016-04-01

Full Text Available In response to its users’ needs, the National Oceanic and Atmospheric Administration (NOAA initiated reanalysis (RAN of the Advanced Very High Resolution Radiometer (AVHRR Global Area Coverage (GAC; 4 km sea surface temperature (SST data employing its Advanced Clear Sky Processor for Oceans (ACSPO retrieval system. Initially, AVHRR/3 data from five NOAA and two Metop satellites from 2002 to 2015 have been reprocessed. The derived SSTs have been matched up with two reference SSTs—the quality controlled in situ SSTs from the NOAA in situ Quality Monitor (iQuam and the Canadian Meteorological Centre (CMC L4 SST analysis—and analyzed in the NOAA SST Quality Monitor (SQUAM online system. The corresponding clear-sky ocean brightness temperatures (BT in AVHRR bands 3b, 4 and 5 (centered at 3.7, 11, and 12 µm, respectively have been compared with the Community Radiative Transfer Model simulations in another NOAA online system, Monitoring of Infrared Clear-sky Radiances over Ocean for SST (MICROS. For some AVHRRs, the time series of “AVHRR minus reference” SSTs and “observed minus model” BTs are unstable and inconsistent, with artifacts in the SSTs and BTs strongly correlated. In the official “Reanalysis version 1” (RAN1, data from only five platforms—two midmorning (NOAA-17 and Metop-A and three afternoon (NOAA-16, -18 and -19—were included during the most stable periods of their operations. The stability of the SST time series was further improved using variable regression SST coefficients, similarly to how it was done in the NOAA/NASA Pathfinder version 5.2 (PFV5.2 dataset. For data assimilation applications, especially those blending satellite and in situ SSTs, we recommend bias-correcting the RAN1 SSTs using the newly developed sensor-specific error statistics (SSES, which are reported in the product files. Relative performance of RAN1 and PFV5.2 SSTs is discussed. Work is underway to improve the calibration of AVHRR/3s and

Medium frequency radiowave absorption at sunrise and sunset times in the geomagnetic anomaly region

International Nuclear Information System (INIS)

Rao, K.R.; Pardo, P.M.R.

1988-01-01

The ionosphere, at lower regions, behaves differently during sunrise and sunset times compared to the others day times. The E layer which is well formed during the day, almost disappears at these times and the effect of solar presence or absence at these altitudes is well evidenced immediately after sunrise or sunset. In the South Atlantic anomaly region, the energetic particle precipitaton complicates the phenomenon comprehension in these times. The carried out studies on presunrise and presunset absorption effects in the period from May to July, 1986, in order to understand the ionization processes in the lower ionospheric regions at these times. (M.C.K.) [pt

SST: Single-Stream Temporal Action Proposals

KAUST Repository

Buch, Shyamal; Escorcia, Victor; Shen, Chuanqi; Ghanem, Bernard; Niebles, Juan Carlos

2017-01-01

Our paper presents a new approach for temporal detection of human actions in long, untrimmed video sequences. We introduce Single-Stream Temporal Action Proposals (SST), a new effective and efficient deep architecture for the generation of temporal action proposals. Our network can run continuously in a single stream over very long input video sequences, without the need to divide input into short overlapping clips or temporal windows for batch processing. We demonstrate empirically that our model outperforms the state-of-the-art on the task of temporal action proposal generation, while achieving some of the fastest processing speeds in the literature. Finally, we demonstrate that using SST proposals in conjunction with existing action classifiers results in improved state-of-the-art temporal action detection performance.

SST: Single-Stream Temporal Action Proposals

KAUST Repository

Buch, Shyamal

2017-11-09

Our paper presents a new approach for temporal detection of human actions in long, untrimmed video sequences. We introduce Single-Stream Temporal Action Proposals (SST), a new effective and efficient deep architecture for the generation of temporal action proposals. Our network can run continuously in a single stream over very long input video sequences, without the need to divide input into short overlapping clips or temporal windows for batch processing. We demonstrate empirically that our model outperforms the state-of-the-art on the task of temporal action proposal generation, while achieving some of the fastest processing speeds in the literature. Finally, we demonstrate that using SST proposals in conjunction with existing action classifiers results in improved state-of-the-art temporal action detection performance.

Quench detection, protection and simulation studies on SST-1 magnets

International Nuclear Information System (INIS)

Sharma, Aashoo N.; Khristi, Yohan; Pradhan, Subrata; Doshi, Kalpesh; Prasad, Upendra; Banaudha, Moni; Varmora, Pankaj; Praghi, Bhadresh R.

2015-01-01

Steady-state Superconducting Tokamak-1 (SST-1) is India's first tokamak with superconducting toroidal field (TF) and Poloidal Field (PF) magnets. These magnets are made with NbTi based Cable-In-Conduit-Conductors. The quench characteristic of SST-1 CICC has been extensively studied both analytically and using simulation codes. Dedicated experiments like model coil test program, TF coil test program and laboratory experiments were conducted to fully characterize the performance of the CICC and the magnets made using this CICC. Results of quench experiments performed during these tests have been used to design the SST-1 quench detection and protection system. Simulation results of TF coil quenches and slow propagation quench of TF busbars have been used to further optimize these systems during the SST-1 tokamak operation. Redundant hydraulic based quench detection is also proposed for the TF coil quench detection. This paper will give the overview of these development and simulation activities. (author)

Cryogenic operation strategy for the SST-1 device

International Nuclear Information System (INIS)

Tanna, V.L.; Pradhan, S.

2013-01-01

The SST-1 has been operated since 2012 as part of its engineering commissioning and almost 5 experimental campaigns have been successfully completed. Before final assembling, cool-down and current excitation tests for the Toroidal field coils and PF 3 (Upper) coil were demonstrated successfully as part of validation under coils test program. These superconducting coils consist of a cable-in-conduit conductor, (CICC) is cooled by the forced-flow Two-phase flow as well as supercritical helium conditions. During the recent campaigns, hydraulic characteristics of whole superconducting magnets along with the TF case cooling were studied as an integral system. Based on the experimental observations, efforts have been made to cryo stable conditions of the SST-1 superconducting magnets system in order to produce steady state TF magnetic field of 1.5 T at the plasma center. Optimization of Helium plant related processes have been worked out and implemented to realize the successful SST-1 device operation over a week. In order to have long experimental campaign, an intermediate temperature cooling down philosophy has been adopted. The complete superconducting coils flow distribution among their cooling channels and pressure head requirements were studied from the measurements. In this paper, we will highlight the recent cool-down results, flow distribution and temperature uniformity aspects while cooling down the SST-1 magnets system. (author)

Determining the Pixel-to-Pixel Uncertainty in Satellite-Derived SST Fields

Directory of Open Access Journals (Sweden)

Fan Wu

2017-08-01

results and the less stringent preprocessing requirements, the variogram is the preferred method, although there is a suggestion that this approach overestimates the noise for high quality data in dynamically quiet regions. Finally, simulations of the impact of noise on the determination of SST gradients show that on average the gradient magnitude for typical ocean gradients will be accurately estimated with VIIRS but substantially overestimated with AVHRR.

The ASTRI SST-2M prototype for the Cherenkov Telescope Array: prototype technologies goals and strategies for the future SST

Science.gov (United States)

Marchiori, Gianpietro; Busatta, Andrea; Giacomel, Stefano; Folla, Ivan; Valsecchi, Marco; Canestrari, Rodolfo; Bonnoli, Giacomo; Cascone, Enrico; Conconi, Paolo; Fiorini, Mauro; Giro, Enrico; La Palombara, Nicola; Pareschi, Giovanni; Perri, Luca; Rodeghiero, Gabriele; Sironi, Giorgia; Stringhetti, Luca; Toso, Giorgio; Tosti, Gino; Pellicciari, Carlo

2014-07-01

The Cherenkov Telescope Array (CTA) observatory will represent the next generation of Imaging Atmospheric Cherenkov Telescope. Using a combination of large-, medium-, and small-scale telescopes (LST, MST, SST, respectively), it will explore the Very High Energy domain from a few tens of GeVup to about few hundreds of TeV with unprecedented sensitivity, angular resolution and imaging quality. In this framework, the Italian ASTRI program, led by the Italian National Institute of Astrophysics (INAF) developed a 4-meter class telescope, which will adopt an aplanatic, wide-field, double-reflection optical layout in a Schwarzschild- Couder configuration. Within this program INAF assigned to the consortium between Galbiati Group and EIE Group the construction, assembly and tests activities of the prototype named ASTRI SST-2M. On the basis of the lesson learnt from the prototype, other telescopes will be produced, starting from a re-design phase, in order to optimize performances and the overall costs and production schedule for the CTA-SST telescope. This paper will firstly give an overview of the concept for the SST prototype mount structure. In this contest, the technologies adopted for the design, manufacturing and tests of the entire system will be presented. Moreover, a specific focus on the challenges of the prototype and the strategies associated with it will be provided, in order to outline the near future performance goals for this type of Cherenkov telescopes employed for Gamma ray science.

Influence of Kuroshio SST front in the East China Sea on the climatological evolution of Meiyu rainband

Science.gov (United States)

Xu, Mimi; Xu, Haiming; Ren, Huijun

2018-02-01

The influence of Kuroshio sea surface temperature (SST) front in the East China Sea (ECS) on the temporal evolution of climatological Meiyu rainband was investigated using a suite of high-resolution satellite observations and a reanalysis dataset from 2000 to 2011. During the northward seasonal march of Meiyu rainband from the warmer flank of the SST front to the colder flank, the climatological rainband strength weakened substantially despite large-scale environment became more conducive to intensify precipitation. A sharp reduction in occurrence frequency of precipitation with relatively shallower depth and smaller intensity was responsible for the weakening of Meiyu rainband. During the northward migration of Meiyu rainband, individual precipitation events became deeper and more intensive, and the contribution of convective precipitation to the rainband was enhanced, associated with the seasonal northward extension of high convective instability region over the ECS. The characteristics of Meiyu rainband evolution were generally supported by cloud observations. When Meiyu rainband was located on the warmer flank of the SST front, local enhanced mean surface wind convergence and variance of convergence at synoptic timescale by the warm SST of the Kuroshio favored strong surface convergence that may trigger precipitation. A detailed moisture budget analysis revealed that the major part of moisture for Meiyu precipitation was supplied by low-level wind convergence, with much smaller contribution from moisture advection. The variation of climatological precipitation associated with Meiyu northward migration depended on SST modulation of both surface evaporation and low-level moisture convergence over the ECS.

Overview of data acquisition and central control system of steady state superconducting Tokamak (SST-1)

Energy Technology Data Exchange (ETDEWEB)

Pradhan, S., E-mail: pradhan@ipr.res.in; Mahajan, K.; Gulati, H.K.; Sharma, M.; Kumar, A.; Patel, K.; Masand, H.; Mansuri, I.; Dhongde, J.; Bhandarkar, M.; Chudasama, H.

2016-11-15

Highlights: • The paper gives overview on SST-1 data acquisition and central control system and future upgrade plans. • The lossless PXI based data acquisition of SST-1 is capable of acquiring around 130 channels with sampling frequency ranging from 10 KHz to 1 MHz sampling frequency. • Design, architecture and technologies used for central control system (CCS) of SST-1. • Functions performed by CCS. - Abstract: Steady State Superconducting Tokamak (SST-1) has been commissioned successfully and has been carrying out limiter assisted ohmic plasma experiments since the beginning of 2014 achieving a maximum plasma current of 75 kA at a central field of 1.5 T and the plasma duration ∼500 ms. In near future, SST-1 looks forward to carrying out elongated plasma experiments and stretching plasma pulses beyond 1 s. The data acquisition and central control system (CCS) for SST-1 are distributed, modular, hierarchical and scalable in nature The CCS has been indigenously designed, developed, implemented, tested and validated for the operation of SST-1. The CCS has been built using well proven technologies like Redhat Linux, vxWorks RTOS for deterministic control, FPGA based hardware implementation, Ethernet, fiber optics backbone for network, DSP for real-time computation & Reflective memory for high-speed data transfer etc. CCS in SST-1 controls & monitors various heterogeneous SST-1 subsystems dispersed in the same campus. The CCS consists of machine control system, basic plasma control system, GPS time synchronization system, storage area network (SAN) for centralize data storage, SST-1 networking system, real-time networks, SST-1 control room infrastructure and many other supportive systems. Machine Control System (MCS) is a multithreaded event driven system running on Linux based servers, where each thread of the software communicates to a unique subsystem for monitoring and control from SST-1 central control room through network programming. The CCS hardware

Overview of data acquisition and central control system of steady state superconducting Tokamak (SST-1)

International Nuclear Information System (INIS)

Pradhan, S.; Mahajan, K.; Gulati, H.K.; Sharma, M.; Kumar, A.; Patel, K.; Masand, H.; Mansuri, I.; Dhongde, J.; Bhandarkar, M.; Chudasama, H.

2016-01-01

Highlights: • The paper gives overview on SST-1 data acquisition and central control system and future upgrade plans. • The lossless PXI based data acquisition of SST-1 is capable of acquiring around 130 channels with sampling frequency ranging from 10 KHz to 1 MHz sampling frequency. • Design, architecture and technologies used for central control system (CCS) of SST-1. • Functions performed by CCS. - Abstract: Steady State Superconducting Tokamak (SST-1) has been commissioned successfully and has been carrying out limiter assisted ohmic plasma experiments since the beginning of 2014 achieving a maximum plasma current of 75 kA at a central field of 1.5 T and the plasma duration ∼500 ms. In near future, SST-1 looks forward to carrying out elongated plasma experiments and stretching plasma pulses beyond 1 s. The data acquisition and central control system (CCS) for SST-1 are distributed, modular, hierarchical and scalable in nature The CCS has been indigenously designed, developed, implemented, tested and validated for the operation of SST-1. The CCS has been built using well proven technologies like Redhat Linux, vxWorks RTOS for deterministic control, FPGA based hardware implementation, Ethernet, fiber optics backbone for network, DSP for real-time computation & Reflective memory for high-speed data transfer etc. CCS in SST-1 controls & monitors various heterogeneous SST-1 subsystems dispersed in the same campus. The CCS consists of machine control system, basic plasma control system, GPS time synchronization system, storage area network (SAN) for centralize data storage, SST-1 networking system, real-time networks, SST-1 control room infrastructure and many other supportive systems. Machine Control System (MCS) is a multithreaded event driven system running on Linux based servers, where each thread of the software communicates to a unique subsystem for monitoring and control from SST-1 central control room through network programming. The CCS hardware

Superconducting magnets and cryogenics for the steady state superconducting tokamak SST-1

International Nuclear Information System (INIS)

Saxena, Y.C.

2000-01-01

SST-1 is a steady state superconducting tokamak for studying the physics of the plasma processes in tokamak under steady state conditions and to learn technologies related to the steady state operation of the tokamak. SST-1 will have superconducting magnets made from NbTi based conductors operating at 4.5 K temperature. The design of the superconducting magnets and the cryogenic system of SST-1 tokamak are described. (author)

Study of the global and regional climatic impacts of ENSO magnitude using SPEEDY AGCM

KAUST Repository

Dogar, Muhammad Mubashar; Kucharski, Fred; Azharuddin, Syed

2017-01-01

ENSO is considered as a strong atmospheric teleconnection that has pronounced global and regional circulation effects. It modifies global monsoon system, especially, Asian and African monsoons. Previous studies suggest that both the frequency and magnitude of ENSO events have increased over the last few decades resulting in a need to study climatic impacts of ENSO magnitude both at global and regional scales. Hence, to better understand the impact of ENSO amplitude over the tropical and extratropical regions focussing on the Asian and African domains, ENSO sensitivity experiments are conducted using ICTPAGCM (‘SPEEDY’). It is anticipated that the tropical Pacific SST forcing will be enough to produce ENSO-induced teleconnection patterns; therefore, the model is forced using NINO3.4 regressed SST anomalies over the tropical Pacific only. SPEEDY reproduces the impact of ENSO over the Pacific, North and South America and African regions very well. However, it underestimates ENSO teleconnection patterns and associated changes over South Asia, particularly in the Indian region, which suggests that the tropical Pacific SST forcing is not sufficient to represent ENSO-induced teleconnection patterns over South Asia. Therefore, SST forcing over the tropical Indian Ocean together with air–sea coupling is also required for better representation of ENSO-induced changes in these regions. Moreover, results obtained by this pacemaker experiment show that ENSO impacts are relatively stronger over the Inter-Tropical Convergence Zone (ITCZ) compared to extratropics and high latitude regions. The positive phase of ENSO causes weakening in rainfall activity over African tropical rain belt, parts of South and Southeast Asia, whereas, the La Niña phase produces more rain over these regions during the summer season. Model results further reveal that ENSO magnitude has a stronger impact over African Sahel and South Asia, especially over the Indian region because of its significant

Study of the global and regional climatic impacts of ENSO magnitude using SPEEDY AGCM

KAUST Repository

Dogar, Muhammad Mubashar

2017-03-09

ENSO is considered as a strong atmospheric teleconnection that has pronounced global and regional circulation effects. It modifies global monsoon system, especially, Asian and African monsoons. Previous studies suggest that both the frequency and magnitude of ENSO events have increased over the last few decades resulting in a need to study climatic impacts of ENSO magnitude both at global and regional scales. Hence, to better understand the impact of ENSO amplitude over the tropical and extratropical regions focussing on the Asian and African domains, ENSO sensitivity experiments are conducted using ICTPAGCM (‘SPEEDY’). It is anticipated that the tropical Pacific SST forcing will be enough to produce ENSO-induced teleconnection patterns; therefore, the model is forced using NINO3.4 regressed SST anomalies over the tropical Pacific only. SPEEDY reproduces the impact of ENSO over the Pacific, North and South America and African regions very well. However, it underestimates ENSO teleconnection patterns and associated changes over South Asia, particularly in the Indian region, which suggests that the tropical Pacific SST forcing is not sufficient to represent ENSO-induced teleconnection patterns over South Asia. Therefore, SST forcing over the tropical Indian Ocean together with air–sea coupling is also required for better representation of ENSO-induced changes in these regions. Moreover, results obtained by this pacemaker experiment show that ENSO impacts are relatively stronger over the Inter-Tropical Convergence Zone (ITCZ) compared to extratropics and high latitude regions. The positive phase of ENSO causes weakening in rainfall activity over African tropical rain belt, parts of South and Southeast Asia, whereas, the La Niña phase produces more rain over these regions during the summer season. Model results further reveal that ENSO magnitude has a stronger impact over African Sahel and South Asia, especially over the Indian region because of its significant

Quench characterization and thermo hydraulic analysis of SST-1 TF magnet busbar

Energy Technology Data Exchange (ETDEWEB)

Sharma, A.N., E-mail: ansharma@ipr.res.in [Institute for Plasma Research, Gandhinagar (India); Pradhan, S. [Institute for Plasma Research, Gandhinagar (India); Duchateau, J.L. [CEA Cadarache, 13108 St Paul lez Durance Cedex (France); Khristi, Y.; Prasad, U.; Doshi, K.; Varmora, P.; Tanna, V.L.; Patel, D.; Panchal, A. [Institute for Plasma Research, Gandhinagar (India)

2015-01-15

Highlights: • Details of SST-1 TF busbar quench detection. • Simulation of slow propagating normal zone. • Thermo hydraulic analyses of TF busbar in current feeder system. - Abstract: Toroidal field (TF) magnet system of steady-state superconducting tokamak-1 (SST-1) has 16 superconducting coils. TF coils are cooled with forced flow supercritical helium at 0.4 MPa, at 4.5 K and operate at nominal current of 10,000 A. Prior to TF magnet system assembly in SST-1 tokamak, each TF coil was tested individually in a test cryostat. During these tests, TF coil was connected to a pair of conventional helium vapor cooled current leads. The connecting busbar was made from the same base cable-in-conduit-conductor (CICC) of SST-1 superconducting magnet system. Quenches experimentally observed in the busbar sections of the single coil test setups have been analyzed in this paper. A steady state thermo hydraulic analysis of TF magnet busbar in actual SST-1 tokamak assembly has been done. The experimental observations of quench and results of relevant thermo hydraulic analyses have been used to predict the safe operation regime of TF magnet system busbar during actual SST-1 tokamak operational scenarios.

Sea surface temperature 1871-2099 in 38 cells in the Caribbean region.

Science.gov (United States)

Sheppard, Charles; Rioja-Nieto, Rodolfo

2005-09-01

Sea surface temperature (SST) data with monthly resolution are provided for 38 cells in the Caribbean Sea and Bahamas region, plus Bermuda. These series are derived from the HadISST1 data set for historical time (1871-1999) and from the HadCM3 coupled climate model for predicted SST (1950-2099). Statistical scaling of the forecast data sets are performed to produce confluent SST series according to a now established method. These SST series are available for download. High water temperatures in 1998 killed enormous amounts of corals in tropical seas, though in the Caribbean region the effects at that time appeared less marked than in the Indo-Pacific. However, SSTs are rising in accordance with world-wide trends and it has been predicted that temperature will become increasingly important in this region in the near future. Patterns of SST rise within the Caribbean region are shown, and the importance of sub-regional patterns within this biologically highly interconnected area are noted.

Density Anomalies in the Mantle and the Gravitational Core-Mantle Interaction

Science.gov (United States)

Kuang, Weijia; Liu, Lanbo

2003-01-01

Seismic studies suggest that the bulk of the mantle is heterogeneous, with density variations in depth as well as in horizontal directions (latitude and longitude). This density variation produces a three- dimensional gravity field throughout the Earth. On the other hand, the core density also varies in both time and space, due to convective core flow. Consequently, the fluid outer core and the solid mantle interact gravitationally due to the mass anomalies in both regions. This gravitational core-mantle interaction could play a significant role in exchange of angular momentum between the core and the mantle, and thus the change in Earth's rotation on time scales of decades and longer. Aiming at estimating the significance of the gravitational core-mantle interaction on Earth's rotation variation, we introduce in our MoSST core dynamics model a heterogeneous mantle, with a density distribution derived from seismic results. In this model, the core convection is driven by the buoyancy forces. And the density variation is determined dynamically with the convection. Numerical simulation is carried out with different parameter values, intending to extrapolate numerical results for geophysical implications.

Novel, potent, and radio-iodinatable somatostatin receptor 1 (sst1) selective analogues.

Science.gov (United States)

Erchegyi, Judit; Cescato, Renzo; Grace, Christy Rani R; Waser, Beatrice; Piccand, Véronique; Hoyer, Daniel; Riek, Roland; Rivier, Jean E; Reubi, Jean Claude

2009-05-14

The proposed sst(1) pharmacophore (J. Med. Chem. 2005, 48, 523-533) derived from the NMR structures of a family of mono- and dicyclic undecamers was used to design octa-, hepta-, and hexamers with high affinity and selectivity for the somatostatin sst(1) receptor. These compounds were tested for their in vitro binding properties to all five somatostatin (SRIF) receptors using receptor autoradiography; those with high SRIF receptor subtype 1 (sst(1)) affinity and selectivity were shown to be agonists when tested functionally in a luciferase reporter gene assay. Des-AA(1,4-6,10,12,13)-[DTyr(2),DAgl(NMe,2naphthoyl)(8),IAmp(9)]-SRIF-Thr-NH(2) (25) was radio-iodinated ((125)I-25) and specifically labeled sst(1)-expressing cells and tissues. 3D NMR structures were calculated for des-AA(1,4-6,10,12,13)-[DPhe(2),DTrp(8),IAmp(9)]-SRIF-Thr-NH(2) (16), des-AA(1,2,4-6,10,12,13)-[DAgl(NMe,2naphthoyl)(8),IAmp(9)]-SRIF-Thr-NH(2) (23), and des-AA(1,2,4-6,10,12,13)-[DAgl(NMe,2naphthoyl)(8),IAmp(9),Tyr(11)]-SRIF-NH(2) (27) in DMSO. Though the analogues have the sst(1) pharmacophore residues at the previously determined distances from each other, the positioning of the aromatic residues in 16, 23, and 27 is different from that described earlier, suggesting an induced fit mechanism for sst(1) binding of these novel, less constrained sst(1)-selective family members.

Long wavelength magnetic anomalies over continental rifts in cratonic region

Science.gov (United States)

Friedman, S. A.; Persaud, P.; Ferre, E. C.; Martín-Hernández, F.; Feinberg, J. M.

2017-12-01

New collections of unaltered mantle xenoliths shed light on potential upper mantle contributions to long wavelength magnetic anomalies (LWMA) in continental rifts in cratonic / shield areas. The new material originates from the East African Rift (Tanzania), the Rio Grande Rift (U.S.A.), the Rhine Rift (Germany), and the West Antarctic Rift (Antarctica). The xenoliths sample the uppermost ( 0.2 or Fe geotherms (>60ºC/km) that are characteristic of rifted regions preclude any contribution to LWMA at depths >10 km. Hence, only upper basalts and hypovolcanic mafic sills would constitute potential magnetic sources. In contrast, the margins of these rifted regions consist of refractory cratonic domains, often characterized by oxidized sublithospheric mantle that host significant concentrations of primary magnetite. The higher NRMs of these peridotites (up to 15 A/m, Qn > 2.5) combined with much lower geotherms (as low as 15ºC/km) allows for a 5 to 10 km layer of uppermost mantle to potentially contribute to LWMA. Assuming that Qn values in rift margins are also gradient across the rift would primarily reflect thermal equilibration over time.

Satellite monitoring temperature conditions spawning area of the Northeast Arctic cod in the Norwegian Sea and assessment its abundance

Science.gov (United States)

Vanyushin, George; Bulatova, Tatiana; Klochkov, Dmitriy; Troshkov, Anatoliy; Kruzhalov, Michail

2013-04-01

In this study, the attempt to consider the relationship between sea surface anomalies of temperature (SST anomalies °C) in spawning area of the Norwegian Arctic cod off the Lofoten islands in coastal zone of the Norwegian Sea and modern cod total stock biomass including forecasting assessment of future cod generation success. Continuous long-term database of the sea surface temperature (SST) was created on the NOAA satellites data. Mean monthly SST and SST anomalies are computed for the selected area on the basis of the weekly SST maps for the period of 1998-2012. These maps were plotted with the satellite SST data, as well as information of vessels, byoies and coastal stations. All data were classified by spawning seasons (March-April) and years. The results indicate that poor and low middle generations of cod (2001, 2006, 2007) occurred in years with negative or extremely high positive anomalies in the spawning area. The SST anomalies in years which were close to normal or some more normal significances provide conditions for appearance strong or very strong generations of cod (1998, 2000, 2002, 2004, 2005, 2006, 2008, 2009). Temperature conditions in concrete years influence on different indexes of cod directly. So, the mean temperature in spawning seasons in years 1999-2005 was ≈5,0°C and SST anomaly - +0,35°C, by the way average year significances indexes of cod were: total stock biomass - 1425,0 th.t., total spawning biomass - 460,0 th.t., recruitment (age 3+) - 535,0 mln. units and landings - 530,0 th.t. In spawning seasons 2006-2012 years the average data were following: mean SST ≈6,0°C, SST anomaly - +1,29°C, total stock biomass - 2185,0 th.t., total spawning biomass - 1211,0 th.t., recruitment (age 3+) - 821,0 mln. units and landings - 600,0 th.t. The SST and SST anomalies (the NOAA satellite data) characterize increase of decrease in input of warm Atlantic waters which form numerous eddies along the flows of the main warm currents thus creating

Interaction between Tropical Atlantic Variability and El Niño-Southern Oscillation.

Science.gov (United States)

Saravanan, R.; Chang, Ping

2000-07-01

The interaction between tropical Atlantic variability and El Niño-Southern Oscillation (ENSO) is investigated using three ensembles of atmospheric general circulation model integrations. The integrations are forced by specifying observed sea surface temperature (SST) variability over a forcing domain. The forcing domain is the global ocean for the first ensemble, limited to the tropical ocean for the second ensemble, and further limited to the tropical Atlantic region for the third ensemble. The ensemble integrations show that extratropical SST anomalies have little impact on tropical variability, but the effect of ENSO is pervasive in the Tropics. Consistent with previous studies, the most significant influence of ENSO is found during the boreal spring season and is associated with an anomalous Walker circulation. Two important aspects of ENSO's influence on tropical Atlantic variability are noted. First, the ENSO signal contributes significantly to the `dipole' correlation structure between tropical Atlantic SST and rainfall in the Nordeste Brazil region. In the absence of the ENSO signal, the correlations are dominated by SST variability in the southern tropical Atlantic, resulting in less of a dipole structure. Second, the remote influence of ENSO also contributes to positive correlations between SST anomalies and downward surface heat flux in the tropical Atlantic during the boreal spring season. However, even when ENSO forcing is absent, the model integrations provide evidence for a positive surface heat flux feedback in the deep Tropics, which is analyzed in a companion study by Chang et al. The analysis of model simulations shows that interannual atmospheric variability in the tropical Pacific-Atlantic system is dominated by the interaction between two distinct sources of tropical heating: (i) an equatorial heat source in the eastern Pacific associated with ENSO and (ii) an off-equatorial heat source associated with SST anomalies near the Caribbean

Heat flux exchange estimation by using ATSR SST data in TOGA area

Science.gov (United States)

Xue, Yong; Lawrence, Sean P.; Llewellyn-Jones, David T.

1995-12-01

The study of phenomena such as ENSO requires consideration of the dynamics and thermodynamics of the coupled ocean-atmosphere system. The dynamic and thermal properties of the atmosphere and ocean are directly affected by air-sea transfers of fluxes of momentum, heat and moisture. In this paper, we present results of turbulent heat fluxes calculated by using two years (1992 and 1993) monthly average TOGA data and ATSR SST data in TOGA area. A comparison with published results indicates good qualitative agreement. Also, we compared the results of heat flux exchange by using ATSR SST data and by using the TOGA bucket SST data. The ATSR SST data set has been shown to be useful in helping to estimate the large space scale heat flux exchange.

Mechanical design of SST-GATE, a dual-mirror telescope for the Cherenkov Telescope Array

Science.gov (United States)

Dournaux, Jean-Laurent; Huet, Jean-Michel; Amans, Jean-Philippe; Dumas, Delphine; Laporte, Philippe; Sol, Hélène; Blake, Simon

2014-07-01

The Cherenkov Telescope Array (CTA) project aims to create the next generation Very High Energy (VHE) gamma-ray telescope array. It will be devoted to the observation of gamma rays over a wide band of energy, from a few tens of GeV to more than 100 TeV. Two sites are foreseen to view the whole sky where about 100 telescopes, composed of three different classes, related to the specific energy region to be investigated, will be installed. Among these, the Small Size class of Telescopes, SSTs, are devoted to the highest energy region, to beyond 100 TeV. Due to the large number of SSTs, their unit cost is an important parameter. At the Observatoire de Paris, we have designed a prototype of a Small Size Telescope named SST-GATE, based on the dual-mirror Schwarzschild-Couder optical formula, which has never before been implemented in the design of a telescope. Over the last two years, we developed a mechanical design for SST-GATE from the optical and preliminary mechanical designs made by the University of Durham. The integration of this telescope is currently in progress. Since the early stages of mechanical design of SST-GATE, finite element method has been used employing shape and topology optimization techniques to help design several elements of the telescope. This allowed optimization of the mechanical stiffness/mass ratio, leading to a lightweight and less expensive mechanical structure. These techniques and the resulting mechanical design are detailed in this paper. We will also describe the finite element analyses carried out to calculate the mechanical deformations and the stresses in the structure under observing and survival conditions.

Evaluating the impact of sea surface temperature (SST) on spatial distribution of chlorophyll-a concentration in the East China Sea

Science.gov (United States)

Ji, Chenxu; Zhang, Yuanzhi; Cheng, Qiuming; Tsou, JinYeu; Jiang, Tingchen; Liang, X. San

2018-06-01

In this study, we analyze spatial and temporal sea surface temperature (SST) and chlorophylla (Chl-a) concentration in the East China Sea (ECS) during the period 2003-2016. Level 3 (4 km) monthly SST and Chl-a data from the Moderate Resolution Imaging Spectroradiometer Satellite (MODIS-Aqua) were reconstructed using the data interpolation empirical orthogonal function (DINEOF) method and used to evaluated the relationship between the two variables. The approaches employed included correlation analysis, regression analysis, and so forth. Our results show that certain strong oceanic SSTs affect Chl-a concentration, with particularly high correlation seen in the coastal area of Jiangsu and Zhejiang provinces. The mean temperature of the high correlated region was 18.67 °C. This finding may suggest that the SST has an important impact on the spatial distribution of Chl-a concentration in the ECS.

The effect of Congo River freshwater discharge on Eastern Equatorial Atlantic climate variability

Energy Technology Data Exchange (ETDEWEB)

Materia, Stefano [Centro Euro-Mediterraneo per i Cambiamenti Climatici, Bologna (Italy); Gualdi, Silvio; Navarra, Antonio [Centro Euro-Mediterraneo per i Cambiamenti Climatici, Bologna (Italy); Istituto Nazionale di Geofisica e Vulcanologia, Bologna (Italy); Terray, Laurent [Sciences de l' Univers au CERFACS, URA1875 CERFACS/CNRS, Toulouse (France)

2012-11-15

The surface ocean explains a considerable part of the inter-annual Tropical Atlantic variability. The present work makes use of observational datasets to investigate the effect of freshwater flow on sea surface salinity (SSS) and temperature (SST) in the Gulf of Guinea. In particular, the Congo River discharges a huge amount of freshwater into the ocean, affecting SSS in the Eastern Equatorial Atlantic (EEA) and stratifying the surface layers. The hypothesis is that an excess of river runoff emphasize stratification, influencing the ocean temperature. In fact, our findings show that SSTs in the Gulf of Guinea are warmer in summers following an anomalously high Congo spring discharge. Vice versa, when the river discharges low freshwater, a cold anomaly appears in the Gulf. The response of SST is not linear: temperature anomalies are considerable and long-lasting in the event of large freshwater flow, while in dry years they are less remarkable, although still significant. An excess of freshwater seems able to form a barrier layer, which inhibits vertical mixing and the entrainment of the cold thermocline water into the surface. Other processes may contribute to SST variability, among which the net input of atmospheric freshwater falling over EEA. Likewise the case of continental runoff from Congo River, warm anomalies occur after anomalously rainy seasons and low temperatures follow dry seasons, confirming the effect of freshwater on SST. However, the two sources of freshwater anomaly are not in phase, so that it is possible to split between atypical SST following continental freshwater anomalies and rainfall anomalies. Also, variations in air-sea fluxes can produce heating and cooling of the Gulf of Guinea. Nevertheless, atypical SSTs cannot be ascribed to fluxes, since the temperature variation induced by them is not sufficient to explain the SST anomalies appearing in the Gulf after anomalous peak discharges. The interaction processes between river runoff, sea

The Role of the Indian Ocean Sector for Prediction of the Coupled Indo-Pacific System: Impact of Atmospheric Coupling

Science.gov (United States)

Hackert, E. C.; Busalacchi, A. J.; Carton, J.; Murtugudde, R.; Arkin, P.; Evans, M. N.

2017-01-01

Indian Ocean (IO) dynamics impact ENSO predictability by influencing wind and precipitation anomalies in the Pacific. To test if the upstream influence of the IO improves ENSO validation statistics, a combination of forced ocean, atmosphere, and coupled models are utilized. In one experiment, the full tropical Indo-Pacific region atmosphere is forced by observed interannual SST anomalies. In the other, the IO is forced by climatological SST. Differences between these two forced atmospheric model experiments spotlight a much richer wind response pattern in the Pacific than previous studies that used idealized forcing and simple linear atmospheric models. Weak westerlies are found near the equator similar to earlier literature. However, at initialization strong easterlies between 30 deg. S to 10 deg. S and 0 deg. N to 25 deg. N and equatorial convergence of the meridional winds across the entire Pacific are unique findings from this paper. The large-scale equatorial divergence west of the dateline and northeasterly-to-northwesterly cross-equatorial flow converging on the equator east of the dateline in the Pacific are generated from interannual IO SST coupling. In addition, off-equatorial downwelling curl impacts large-scale oceanic waves (i.e., Rossby waves reflect as western boundary Kelvin waves). After 3 months, these downwelling equatorial Kelvin waves propagate across the Pacific and strengthen the NINO3 SST. Eventually Bjerknes feedbacks take hold in the eastern Pacific which allows this warm anomaly to grow. Coupled forecasts for NINO3 SST anomalies for 1993-2014 demonstrate that including interannual IO forcing significantly improves predictions for 3-9 month lead times.

The role of the Indian Ocean sector for prediction of the coupled Indo-Pacific system: Impact of atmospheric coupling

Science.gov (United States)

Hackert, E. C.; Busalacchi, A. J.; Carton, J.; Murtugudde, R.; Arkin, P.; Evans, M. N.

2017-04-01

Indian Ocean (IO) dynamics impact ENSO predictability by influencing wind and precipitation anomalies in the Pacific. To test if the upstream influence of the IO improves ENSO validation statistics, a combination of forced ocean, atmosphere, and coupled models are utilized. In one experiment, the full tropical Indo-Pacific region atmosphere is forced by observed interannual SST anomalies. In the other, the IO is forced by climatological SST. Differences between these two forced atmospheric model experiments spotlight a much richer wind response pattern in the Pacific than previous studies that used idealized forcing and simple linear atmospheric models. Weak westerlies are found near the equator similar to earlier literature. However, at initialization strong easterlies between 30°S-10°S and 0°N-25°N and equatorial convergence of the meridional winds across the entire Pacific are unique findings from this paper. The large-scale equatorial divergence west of the dateline and northeasterly-to-northwesterly cross-equatorial flow converging on the equator east of the dateline in the Pacific are generated from interannual IO SST coupling. In addition, off-equatorial downwelling curl impacts large-scale oceanic waves (i.e., Rossby waves reflect as western boundary Kelvin waves). After 3 months, these downwelling equatorial Kelvin waves propagate across the Pacific and strengthen the NINO3 SST. Eventually Bjerknes feedbacks take hold in the eastern Pacific which allows this warm anomaly to grow. Coupled forecasts for NINO3 SST anomalies for 1993-2014 demonstrate that including interannual IO forcing significantly improves predictions for 3-9 month lead times.

Tropical Indian Ocean warming contributions to China winter climate trends since 1960

Science.gov (United States)

Wu, Qigang; Yao, Yonghong; Liu, Shizuo; Cao, DanDan; Cheng, Luyao; Hu, Haibo; Sun, Leng; Yao, Ying; Yang, Zhiqi; Gao, Xuxu; Schroeder, Steven R.

2018-01-01

This study investigates observed and modeled contributions of global sea surface temperature (SST) to China winter climate trends in 1960-2014, including increased precipitation, warming through about 1997, and cooling since then. Observations and Atmospheric Model Intercomparison Project (AMIP) simulations with prescribed historical SST and sea ice show that tropical Indian Ocean (TIO) warming and increasing rainfall causes diabatic heating that generates a tropospheric wave train with anticyclonic 500-hPa height anomaly centers in the TIO or equatorial western Pacific (TIWP) and northeastern Eurasia (EA) and a cyclonic anomaly over China, referred to as the TIWP-EA wave train. The cyclonic anomaly causes Indochina moisture convergence and southwesterly moist flow that enhances South China precipitation, while the northern anticyclone enhances cold surges, sometimes causing severe ice storms. AMIP simulations show a 1960-1997 China cooling trend by simulating increasing instead of decreasing Arctic 500-hPa heights that move the northern anticyclone into Siberia, but enlarge the cyclonic anomaly so it still simulates realistic China precipitation trend patterns. A separate idealized TIO SST warming simulation simulates the TIWP-EA feature more realistically with correct precipitation patterns and supports the TIWP-EA teleconnection as the primary mechanism for long-term increasing precipitation in South China since 1960. Coupled Model Intercomparison Project (CMIP) experiments simulate a reduced TIO SST warming trend and weak precipitation trends, so the TIWP-EA feature is absent and strong drying is simulated in South China for 1960-1997. These simulations highlight the need for accurately modeled SST to correctly attribute regional climate trends.

Climate Prediction Center Indonesia Sea Level Pressure (1949-present)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This is one of the CPC?s Monthly Atmospheric and SST Indices. It contains standardized sea level pressure anomalies over the equatorial Indonesia region...

Single-Shell Tank (SST) Retrieval Sequence Fiscal Year 2000 Update

International Nuclear Information System (INIS)

GARFIELD, J.S.

2000-01-01

This document describes the baseline single-shell tank (SST) waste retrieval sequence for the River Protection Project (RPP) updated for Fiscal Year 2000. The SST retrieval sequence identifies the proposed retrieval order (sequence), the tank selection and prioritization rationale, and planned retrieval dates for Hanford SSTs. In addition, the tank selection criteria and reference retrieval method for this sequence are discussed

Worldwide surface temperature trends since the mid-19th century

International Nuclear Information System (INIS)

Parker, D.E.; Folland, C.K.

1990-01-01

Sea surface temperatures (SSTs) for the period 1856 to the present have been corrected to compensate for the use of uninsulated buckets prior to the early 1940s. Trends in the corrected SST are consistent with trends in independently corrected nighttime marine air temperatures (NMAT). Global-scale patterns of variation of annual anomalies of SST and NMAT, as revealed by the first three covariance eigenvectors, are also in close agreement. The corrected SST anomalies are also compared with those of nearby coastal and island land air temperatures. Global-scale agreement is good except in the early 20th century when the land data were relatively warm by up to 0.2 C. Proposed causes are the siting of thermometers in open-sided thatched sheds in tropical regions at that time, along with a marked tendency to warm westerly atmospheric circulation over Europe in winter. Combined fields of SST and land air temperature are presented. The relative overall coldness of the late 19th century land air temperatures appears to have arisen from inner-continental and high-latitude regions, especially in winter. Combined fields do not yield full global coverage even in the 1980s, so satellite-based SST data need to be blended carefully with the ship-based observations if monitoring of global climate is to be complete

Worldwide surface temperature trends since the mid-19th century

International Nuclear Information System (INIS)

Parker, D.E.; Folland, C.K.

1991-01-01

Sea surface temperatures (SSTs) for the period 1856 to the present have been corrected to compensate for the use of uninsulated buckets prior to the early 1940s. Trends in the corrected SST are consistent with trends in independently corrected nighttime marine air temperatures (NMAT). Global-scale patterns of variation of annual anomalies of SST and NMAT, as revealed by the first three covariance eigenvectors, are also in close agreement. The corrected SST anomalies are also compared with those of nearby coastal and island land air temperatures. Global-scale agreement is good except in the early 20th century when the land data were relatively warm by up to 0.2 C. Proposed causes are the siting of thermometers in open-sided thatched sheds in tropical regions at that time, along with a marked tendency to warm westerly atmospheric circulation over Europe in winter. Combined fields of SST and land air temperature are presented. The relative overall coldness of the late 19th century land air temperatures appears to have arisen from inner-continental and high-latitude regions, especially in winter. Combined fields do not yield full global coverage even in the 1980s, so satellite-based SST data need to be blended carefully with the ship-based observations if monitoring of global climate is to be complete. 32 refs.; 16 figs

Atlantic water variability on the SE Greenland continental shelf and its relationship to SST

Science.gov (United States)

Sutherland, D. A.; Straneo, F.; Rosing-Asvid, A.; Stenson, G.; Davidson, F. J.; Hammill, M.

2012-12-01

Interaction of warm, Atlantic-origin water (AW) and colder, polar origin water (PW) advecting southward in the East Greenland Current (EGC) influences the heat content of water entering Greenland's outlet glacial fjords. Here we use depth and temperature data derived from deep-diving seals to map out water mass variability across the continental shelf and to augment existing bathymetric products. We find two dominant modes in the vertical temperature structure: a cold mode, with the typical AW/PW layering observed in the EGC, and a warm mode, where AW is present throughout the water column. The prevalence of these modes varies seasonally and spatially across the continental shelf, implying distinct AW pathways. In addition, we find that satellite sea surface temperatures (SST) correlate significantly with temperatures in the upper 50 m (R=0.54), but this correlation decreases with depth (R=0.22 at 200 m), and becomes insignificant below 250 m. Thus, care must be taken in using SST as a proxy for heat content, as AW mainly resides in these deeper layers. Regional map showing the location of all seal tracks originating from Canada and Greenland (stars). Tracks passing inside (red) or outside (blue) the SE Greenland region (black) were subdivided into continental shelf regions (green boxes) near Sermilik Fjord (SF), Cape Farewell (CF) and Kangerdlugssuaq Fjord (KG). GEBCO bathymetry is contoured at 200, 1000, 2000, and 3000 m.

Future changes in tropical cyclone activity projected by multi-physics and multi-SST ensemble experiments using the 60-km-mesh MRI-AGCM

Energy Technology Data Exchange (ETDEWEB)

Murakami, Hiroyuki [Japan Agency for Marine-Earth Science and Technology (JAMSTEC)/Meteorological Research Institute (MRI), Tsukuba, Ibaraki (Japan); University of Hawaii at Manoa, International Pacific Research Center, School of Ocean and Earth Science and Technology, Honolulu, Hawaii (United States); Mizuta, Ryo; Shindo, Eiki [Meteorological Research Institute (MRI), Climate Research Department, Tsukuba, Ibaraki (Japan)

2012-11-15

Uncertainties in projected future changes in tropical cyclone (TC) activity are investigated using future (2075-2099) ensemble projections of global warming under the Intergovernmental Panel on Climate Change (IPCC) A1B scenario. Twelve ensemble experiments are performed using three different cumulus convection schemes and four different assumptions for prescribed future sea surface temperatures (SSTs). All ensemble experiments consistently project significant reductions in global and hemispheric TC genesis numbers as well as reductions in TC frequency of occurrence (TCF) and TC genesis frequency (TGF) in the western North Pacific, South Indian Ocean, and South Pacific Ocean. TCF and TGF are projected to increase over the central Pacific which is consistent with the findings of Li et al. (2010). Inter-experimental variations of projected future changes in TGF and TC genesis number are caused mainly by differences in large-scale dynamical parameters and SST anomalies. Thermodynamic parameters are of secondary importance for variations in TGF and TC genesis number. These results imply that differences in SST spatial patterns can cause substantial variations and uncertainties in projected future changes of TGF and TC numbers at ocean-basin scales. (orig.)

Modeling of self-potential anomalies near vertical dikes.

Science.gov (United States)

Fitterman, D.V.

1983-01-01

The self-potential (SP) Green's function for an outcropping vertical dike is derived from solutions for the dc resistivity problem for the same geometry. The Green's functions are numerically integrated over rectangular source regions on the contacts between the dike and the surrounding material to obtain the SP anomaly. The analysis is valid for thermoelectrical source mechanisms. Two types of anomalies can be produced by this geometry. When the two source planes are polarized in opposite directions, a monopolar anomaly is produced. This corresponds to the thermoelectrical properties of the dike being in contrast with the surrounding material. When the thermoelectric coefficients change monotonically across the dike, a dipolar anomaly is produced. In either case positive and negative anomalies are possible, and the greatest variation in potential will occur in the most resistive regions. -Author

Vertical Motion Changes Related to North-East Brazil Rainfall Variability: a GCM Simulation

Science.gov (United States)

Roucou, Pascal; Oribe Rocha de Aragão, José; Harzallah, Ali; Fontaine, Bernard; Janicot, Serge

1996-08-01

The atmospheric structure over north-east Brazil during anomalous rainfall years is studied in the 11 levels of the outputs of the Laboratoire de Météorologie Dynamique atmospheric general circulation model (LMD AGCM). Seven 19-year simulations were performed using observed sea-surface temperature (SST) corresponding to the period 1970- 1988. The ensemble mean is calculated for each month of the period, leading to an ensemble-averaged simulation. The simulated March-April rainfall is in good agreement with observations. Correlations of simulated rainfall and three SST indices relative to the equatorial Pacific and northern and southern parts of the Atlantic Ocean exhibit stronger relationships in the simulation than in the observations. This is particularly true with the SST gradient in the Atlantic (Atlantic dipole). Analyses on 200 ;hPa velocity potential, vertical velocity, and vertical integral of the zonal component of mass flux are performed for years of abnormal rainfall and positive/negative SST anomalies in the Pacific and Atlantic oceans in March-April during the rainy season over the Nordeste region. The results at 200 hPa show a convergence anomaly over Nordeste and a divergence anomaly over the Pacific concomitant with dry seasons associated with warm SST anomalies in the Pacific and warm (cold) waters in the North (South) Atlantic. During drought years convection inside the ITCZ indicated by the vertical velocity exhibits a displacement of the convection zone corresponding to a northward migration of the ITCZ. The east-west circulation depicted by the zonal divergent mass flux shows subsiding motion over Nordeste and ascending motion over the Pacific in drought years, accompanied by warm waters in the eastern Pacific and warm/cold waters in northern/southern Atlantic. Rainfall variability of the Nordeste rainfall is linked mainly to vertical motion and SST variability through the migration of the ITCZ and the east-west circulation.

Development of the Wintertime Sr/Ca-SST Record from Red Sea Corals as a Proxy for the North Atlantic Oscillation

Science.gov (United States)

Bernstein, W. N.; Hughen, K. A.

2009-12-01

The North Atlantic Oscillation (NAO) is one of the most pronounced and influential patterns in winter atmospheric circulation variability. This meridional redistribution of atmospheric mass across the Atlantic Ocean produces large changes in the intensity, number and direction of storms generated within the basin, and the regional climate of surrounding continents. The NAO exerts a significant impact on society, through influences on agriculture, fisheries, water management, energy generation and coastal development. NAO effects on climate extend from eastern North America across Europe to the eastern Mediterranean and Middle East. Changes in NAO behavior during the late 20th century have been linked to global warming; yet despite its importance, the causes and long-term patterns of NAO variability in the past remain poorly understood. In order to better predict the influence of the NAO on climate in the future, it is critical to examine multi-century NAO variability. The Red Sea is an excellent location from which to generate long NAO records for two reasons. First, patterns of wintertime sea surface temperature (SST) and salinity (SSS) in the Red Sea are highly correlated with NAO variability (Visbeck et al. 2001; Hurrell et al. 2003). Second, the tropical/subtropical Red Sea region contains fast growing long-lived massive Porites spp. corals with annually banded skeletons. These corals are ideal for generating well-dated high-resolution paleoclimatic records that extend well beyond the instrumental period. Here we present a study of winter SST and NAO variability in the Red sea region based on coral Sr/Ca data. In 2008, we collected multiple drill cores ranging in length from 1 to 4.1 meters from Porites corals at six sites spanning a large SST gradient. Sr/Ca measurements from multiple corals will be regressed against 23 years of satellite SST data, expanding the SST range over which we calibrate. A sampling resolution of 0.5mm will yield greater than bi

Experience of superconducting current feeders system of SST-1

International Nuclear Information System (INIS)

Gupta, N.C.; Garg, A.; Sonara, D.

2014-01-01

The superconducting current feeder system for SST-1 which has been installed and commissioned recently along with SST-1, felicitates to energize the SST-1. The CFS consists of ten pairs of 10,000 Ampere (A) rating helium vapor cooled conventional current leads, interconnecting Cu-SC joints, three numbers of cryo-compatible SC feeders ducts, current leads assembly chamber, hydraulic network and three numbers of joint boxes operated at different current rating to charge Toroidal Field and Poloidal Field coils separately. During the last three campaigns, it was possible to achieve a controlled cool down up to 4 K and showed its rated operational performance. Actively cooled liquid nitrogen shield showed temperature profile in the temperature range of 80-85K and the whole system was evacuated up to 6x10 -6 mbar. The measured LHe consumption rates from TF VCCL were 0.3 g/s and 0.35 g/s at zero current and 1 kA respectively. (author)

Distant Influence of Kuroshio Eddies on North Pacific Weather Patterns?

Science.gov (United States)

Ma, Xiaohui; Chang, Ping; Saravanan, R; Montuoro, Raffaele; Hsieh, Jen-Shan; Wu, Dexing; Lin, Xiaopei; Wu, Lixin; Jing, Zhao

2015-12-04

High-resolution satellite measurements of surface winds and sea-surface temperature (SST) reveal strong coupling between meso-scale ocean eddies and near-surface atmospheric flow over eddy-rich oceanic regions, such as the Kuroshio and Gulf Stream, highlighting the importance of meso-scale oceanic features in forcing the atmospheric planetary boundary layer (PBL). Here, we present high-resolution regional climate modeling results, supported by observational analyses, demonstrating that meso-scale SST variability, largely confined in the Kuroshio-Oyashio confluence region (KOCR), can further exert a significant distant influence on winter rainfall variability along the U.S. Northern Pacific coast. The presence of meso-scale SST anomalies enhances the diabatic conversion of latent heat energy to transient eddy energy, intensifying winter cyclogenesis via moist baroclinic instability, which in turn leads to an equivalent barotropic downstream anticyclone anomaly with reduced rainfall. The finding points to the potential of improving forecasts of extratropical winter cyclones and storm systems and projections of their response to future climate change, which are known to have major social and economic impacts, by improving the representation of ocean eddy-atmosphere interaction in forecast and climate models.

Response of the Asian summer monsoon to changes in El Niño properties

Science.gov (United States)

Annamalai, H.; Liu, P.

2005-04-01

stronger ISM and WNPM. During PRE76 the non-occurrence of cold SST anomalies over the Indo-Pacific warm pool reinforces El Niño's suppression on the ISM.In contrast, TIO solutions show a reduced ISM during July-August of POST76; the solutions, however, show a significant effect on the WNPM during both PRE76 and POST76 periods. It is argued that SSTs over the entire tropical Indo-Pacific region need to be considered to understand the El Niño Southern Oscillation-monsoon linkage, and to make predictions of rainfall over India and the western North Pacific.

Reconstructing Tropical Southwest Pacific Climate Variability and Mean State Changes at Vanuatu during the Medieval Climate Anomaly using Geochemical Proxies from Corals

Science.gov (United States)

Lawman, A. E.; Quinn, T. M.; Partin, J. W.; Taylor, F. W.; Thirumalai, K.; WU, C. C.; Shen, C. C.

2017-12-01

The Medieval Climate Anomaly (MCA: 950-1250 CE) is identified as a period during the last 2 millennia with Northern Hemisphere surface temperatures similar to the present. However, our understanding of tropical climate variability during the MCA is poorly constrained due to a lack of sub-annually resolved proxy records. We investigate seasonal and interannual variability during the MCA using geochemical records developed from two well preserved Porites lutea fossilized corals from the tropical southwest Pacific (Tasmaloum, Vanuatu; 15.6°S, 166.9°E). Absolute U/Th dates of 1127.1 ± 2.7 CE and 1105.1 ± 3.0 CE indicate that the selected fossil corals lived during the MCA. We use paired coral Sr/Ca and δ18O measurements to reconstruct sea surface temperature (SST) and the δ18O of seawater (a proxy for salinity). To provide context for the fossil coral records and test whether the mean state and climate variability at Vanuatu during the MCA is similar to the modern climate, our analysis also incorporates two modern coral records from Sabine Bank (15.9°S, 166.0°E) and Malo Channel (15.7°S, 167.2°E), Vanuatu for comparison. We quantify the uncertainty in our modern and fossil coral SST estimates via replication with multiple, overlapping coral records. Both the modern and fossil corals reproduce their respective mean SST value over their common period of overlap, which is 25 years in both cases. Based on over 100 years of monthly Sr/Ca data from each time period, we find that SSTs at Vanuatu during the MCA are 1.3 ± 0.7°C cooler relative to the modern. We also find that the median amplitude of the annual cycle is 0.8 ± 0.3°C larger during the MCA relative to the modern. Multiple data analysis techniques, including the standard deviation and the difference between the 95th and 5th percentiles of the annual SST cycle estimates, also show that the MCA has greater annual SST variability relative to the modern. Stable isotope data acquisition is ongoing, and when

[Births prevalence of 27 selected congenital anomalies in 7 geographic regions of Argentina].

Science.gov (United States)

Campaña, Hebe; Pawluk, Mariela S; López Camelo, Jorge S

2010-10-01

The aim of the present work was to estimate the frequency of 27 birth defects in 7 geographical regions of Argentina. Observational, cross-sectional, descriptive design. A sample of 21,844 new born with birth defects was selected, ascertained from 855,220 births, between 1994 and 2007, in 59 hospitals belonging to the ECLAMC network. In order to identify regions of high frequency a Poisson regression was used, adjusted by different hospitals from the same region. The model included a time variable to detect secular trends and 6 dummy variables for 7 predefined geographical regions: Metropolitana (MET); Pampa (PAM); Centro (CEN); Cuyo (CUY); Noroeste (NOA); Nordeste (NEA) and Patagonia (PAT). High frequencies regional analysis showed the following significant results: PAM: severe hypospadias; CEN: spina bifida, microtia, cleft lip with cleft palate, polycystic kidney, postaxial polydactyly and Down syndrome; CUY: postaxial polydactyly; NOA: omphalocele, gastroschisis, cleft lip without cleft palate, cleft lip with cleft palate, anorectal atresia/stenosis, indeterminate sex, preaxial polydactyly and pectoral agenesis; PAT: cleft lip without cleft palate. Out of the 27 congenital anomalies analyzed, fourteen showed a frequency significatively higher in one or more regions.

Test results on systems developed for SST-1 tokamak

International Nuclear Information System (INIS)

Bora, D.

2003-01-01

Steady state Superconducting Tokamak (SST-1) is a large aspect ratio tokamak, configured to run double null diverted plasmas with significant elongation (κ) and triangularity Superconducting (SC) magnets are deployed for both the toroidal and poloidal field coils in SST-1. A NbTi based cable-in-conduit conductor (CICC) has been fabricated by M/S Hitachi Cables Ltd., Japan under specification and supervision of IPR. The suitability of this CICC for the SST-1 magnets has been validated through test carried out on a model coil (MC) wound from this CICC. Toroidal and poloidal SC magnets have been fabricated and factory acceptance tests have been performed. SC magnets require liquid helium (LHe) cooled current leads, electrical isolators at LHe temperature, superconducting bus bars and LHe transfer lines. Full scale prototypes of these have been developed and tested successfully. SC magnets will be cooled to 4.5K by forced flow of supercritical Helium through the CICC. A 1 kW grade liquefier/refrigerator has been installed and is in final stages of commissioning at IPR. SST-1 deploys a fully welded ultra high vacuum vessel, made up of 16 vessel sectors having ports and 16 rings with D-shaped cross-section. To establish the fabrication methodology for this, a full scale proto-type of the vessel with two vessel sectors and three rings has been fabricated and tested successfully. Based on this the fabrication of the vessel sectors and rings is in final stage of fabrication. Liquid nitrogen cooled radiation shield are deployed between the vacuum vessel and SC magnets as well as SC magnets and cryostat, to minimize the radiation losses at the SC magnets. SST-1 will have three different high power radio frequency (RF) systems to additionally heat and non-inductively drive plasma current to sustain the plasma in steady state for a duration of up to 1000 sec. Ion cyclotron resonance frequency (ICRF) and electron cyclotron resonance frequency (ECRF) systems will primarily be

On the warm nearshore bias in Pathfinder monthly SST products over Eastern Boundary upwelling systems

CSIR Research Space (South Africa)

Dufois, F

2012-01-01

Full Text Available Using in situ sea surface temperature (SST) data and MODIS/TERRA SST, the monthly AVHRR Pathfinder (version 5.0 and 5.2) SST product was evaluated within the four main Eastern Boundary Upwelling Systems. A warm bias in the monthly Pathfinder data...

A 20 year independent record of sea surface temperature for climate from Along-Track Scanning Radiometers

Science.gov (United States)

Merchant, Christopher J.; Embury, Owen; Rayner, Nick A.; Berry, David I.; Corlett, Gary K.; Lean, Katie; Veal, Karen L.; Kent, Elizabeth C.; Llewellyn-Jones, David T.; Remedios, John J.; Saunders, Roger

2012-12-01

A new record of sea surface temperature (SST) for climate applications is described. This record provides independent corroboration of global variations estimated from SST measurements made in situ. Infrared imagery from Along-Track Scanning Radiometers (ATSRs) is used to create a 20 year time series of SST at 0.1° latitude-longitude resolution, in the ATSR Reprocessing for Climate (ARC) project. A very high degree of independence of in situ measurements is achieved via physics-based techniques. Skin SST and SST estimated for 20 cm depth are provided, with grid cell uncertainty estimates. Comparison with in situ data sets establishes that ARC SSTs generally have bias of order 0.1 K or smaller. The precision of the ARC SSTs is 0.14 K during 2003 to 2009, from three-way error analysis. Over the period 1994 to 2010, ARC SSTs are stable, with better than 95% confidence, to within 0.005 K yr-1(demonstrated for tropical regions). The data set appears useful for cleanly quantifying interannual variability in SST and major SST anomalies. The ARC SST global anomaly time series is compared to the in situ-based Hadley Centre SST data set version 3 (HadSST3). Within known uncertainties in bias adjustments applied to in situ measurements, the independent ARC record and HadSST3 present the same variations in global marine temperature since 1996. Since the in situ observing system evolved significantly in its mix of measurement platforms and techniques over this period, ARC SSTs provide an important corroboration that HadSST3 accurately represents recent variability and change in this essential climate variable.

Non-inductive current drive and RF heating in SST-1 tokamak

International Nuclear Information System (INIS)

2000-01-01

Steady state superconducting tokamak (SST-1) machine is being developed for 1000 sec operation at different operating parameters. Radio Frequency (RF) and neutral beam injection (NBI) methods are planned in SST-1 for noninductive current drive and heating. In this paper, we describe the non-inductive current drive and RF heating methods that are being developed for this purpose. SST-1 is a large aspect ratio tokamak configured to run double-null divertor plasmas with significant elongation (κ = 1.7-1.9) and triangularity (δ = 0.4-0.7). SST-1 has a major radius of 1.1 in and minor radius of 0.2 m. Circular and shaped plasma experiments would be conducted at 1.5 and 3 T toroidal magnetic field in three different phases with I p = 110 kA and 220 kA. Two main factors have been considered during the development of auxiliary systems, namely, high heat flux (1 MW/m 2 ) incident on the plasma facing antennae components and fast feedback for constant power input due to small energy confinement time (∼ 10 ms). (author)

Dental Anomalies: An Update

Directory of Open Access Journals (Sweden)

Fatemeh Jahanimoghadam

2016-01-01

Full Text Available Dental anomalies are usual congenital malformation that can happen either as isolated findings or as a part of a syndrome. Developmental anomalies influencing the morphology exists in both deciduous and permanent dentition and shows different forms such as gemination, fusion, concrescence, dilaceration, dens evaginatus (DE, enamel pearls, taurodontism or peg-shaped laterals. All These anomalies have clinical significance concerning aesthetics, malocclusion and more necessary preparing of the development of dental decays and oral diseases. Through a search in PubMed, Google, Scopus and Medline, a total of eighty original research papers during 1928-2016 were found with the keywords such as dental anomaly, syndrome, tooth and hypodontia. One hundred review titles were identified, eighty reviews were retrieved that were finally included as being relevant and of sufficient quality. In this review, dental anomalies including gemination, fusion, concrescence, dilaceration, dens invaginatus, DE, taurodontism, enamel pearls, fluorosis, peg-shaped laterals, dentinal dysplasia, regional odontodysplasia and hypodontia are discussed. Diagnosing dental abnormality needs a thorough evaluation of the patient, involving a medical, dental, familial and clinical history. Clinical examination and radiographic evaluation and in some of the cases, specific laboratory tests are also needed. Developmental dental anomalies require careful examination and treatment planning. Where one anomaly is present, clinicians should suspect that other anomalies may also be present. Moreover, careful clinical and radiographical examination is required. Furthermore, more complex cases need multidisciplinary planning and treatment.

Do three massive coral species from the same reef record the same SST signal? A test from the Dry Tortugas, Florida Keys

Science.gov (United States)

DeLong, K.L.; Poore, R.Z.; Reich, C.D.; Flannery, J.A.; Maupin, Christopher R.; Quinn, T.M.

2010-01-01

�S. siderea; >0.90 D. strigosa; >0.83 M. faveolata; p weighted linear regression of monthly coral Sr/Ca to mean monthly SST revealed that S. sidereacaptured the seasonal and interannual variability in SST (r = -0.97, -0.61 monthly and monthly anomalies, respectively, p corals have reduced correlation with monthly anomalies and do not capture the seasonal variability with the same fidelity as S. siderea. All three corals were sampled along the thecal wall following the same procedures; however, each coral species has a different skeletal structure, density, and micro-scale growth patterns. We hypothesize the thecal wall of S. siderea calcifies at a continuous rate along the time-growth axis whereas the wall of D. strigosa and M. faveolata reflects a more complex signal. Of the three species, the slow growing S. siderea provides a robust reconstruction of mean monthly SST for the Dry Tortugas thus suitable for longer centennial-scale reconstructions.

Variability of the Tropical Ocean Surface Temperatures at Decadal-Multidecadal Timescales. Part I: The Atlantic Ocean.

Science.gov (United States)

Mehta, Vikram M.

1998-09-01

Gridded time series from the Global Ocean Surface Temperature Atlas were analyzed with a variety of techniques to identify spatial structures and oscillation periods of the tropical Atlantic sea surface temperature (SST) variations at decadal timescales, and to develop physical interpretations of statistical patterns of decadal SST variations. Each time series was 110 yr (1882-1991) long. The tropical Atlantic SST variations were compared with decadal variations in a 74-yr-long (1912-85) north Nordeste Brazil rainfall time series and a 106-yr-long (1886-1991) tropical Atlantic cyclone activity index time series. The tropical Atlantic SST variations were also compared with decadal variations in the extratropical Atlantic SST.Multiyear to multidecadal variations in the cross-equatorial dipole pattern identified as a dominant empirical pattern of the tropical Atlantic SST variations in earlier and present studies are shown to be variations in the approximately north-south gradient of SST anomalies. It is also shown that there was no dynamical-thermodynamical, dipole mode of SST variations during the analysis period. There was a distinct decadal timescale (12-13 yr) of SST variations in the tropical South Atlantic, whereas no distinct decadal timescale was found in the tropical North Atlantic SST variations. Approximately 80% of the coherent decadal variance in the cross-equatorial SST gradient was `explained' by coherent decadal oscillations in the tropical South Atlantic SSTs. There were three, possibly physical, modes of decadal variations in the tropical Atlantic SSTs during the analysis period. In the more energetic mode of the North Atlantic decadal SST variations, anomalies traveled into the tropical North Atlantic from the extratropical North Atlantic along the eastern boundary of the basin. The anomalies strengthened and resided in the tropical North Atlantic for several years, then frequently traveled northward into the mid-high-latitude North Atlantic along

Using a 1-D model to reproduce diurnal SST signals

DEFF Research Database (Denmark)

Karagali, Ioanna; Høyer, Jacob L.

2014-01-01

The diurnal variability of SST has been extensively studied as it poses challenges for validating and calibrating satellite sensors, merging SST time series, oceanic and atmospheric modelling. As heat is significantly trapped close to the surface, the diurnal signal’s maximum amplitude is best...... captured by radiometers. The availability of infra-red retrievals from a geostationary orbit allows the hourly monitoring of the diurnal SST evolution. When infra-red SSTs are validated with in situ measurements a general mismatch is found, associated with the different reference depth of each type...... of measurement. A generally preferred approach to bridge the gap between in situ and remotely obtained measurements is through modelling of the upper ocean temperature. This ESA supported study focuses on the implementation of the 1 dimensional General Ocean Turbulence Model (GOTM), in order to resolve...

Design of mass flow rate measurement system for SST-1 superconducting magnet system

Energy Technology Data Exchange (ETDEWEB)

Varmora, P., E-mail: pvamora@ipr.res.in; Sharma, A.N.; Khristi, Y.; Prasad, U.; Patel, D.; Doshi, K.; Pradhan, S.

2016-11-15

Highlights: • Design of Venturi meter for SST-1 magnet system. • Details of Helium mass flow measurement system used in SST-1. • Instruments and measurement techniques for flow measurement. • VME based data acquisition system details and flow calculation and results from SST-1 campaigns. - Abstract: Superconducting Magnet System (SCMS) of Steady State Superconducting Tokamak – 1 (SST-1) is forced-flow cooled by a closed cycle 1.3 kW (at 4.5 K) class Helium Refrigerator cum Liquefier (HRL) system. An accurate measurement of helium mass flow rate in different coils is required to ensure the uniform cooling of the cold mass in the entire range of operating temperature (300 K to 4.5 K) and pressure (0.9–0.4 MPa). To meet this requirement, indigenously designed and fabricated venturi meters are installed on 27 different coils of SST-1 SCMS. A VME based Data Acquisition System (DAS) has been developed and used to acquire the flow measurement data from different flowmeters. The details of the design of venturi meter, its different measurement and signal conditioning components, the data acquisition system and the mass flow rate calculation method are described in this paper. The mass flow rate measurement data from cryogenic acceptance and SST-1 magnet commissioning experiments are also presented and discussed in this paper.

Design of mass flow rate measurement system for SST-1 superconducting magnet system

International Nuclear Information System (INIS)

Varmora, P.; Sharma, A.N.; Khristi, Y.; Prasad, U.; Patel, D.; Doshi, K.; Pradhan, S.

2016-01-01

Highlights: • Design of Venturi meter for SST-1 magnet system. • Details of Helium mass flow measurement system used in SST-1. • Instruments and measurement techniques for flow measurement. • VME based data acquisition system details and flow calculation and results from SST-1 campaigns. - Abstract: Superconducting Magnet System (SCMS) of Steady State Superconducting Tokamak – 1 (SST-1) is forced-flow cooled by a closed cycle 1.3 kW (at 4.5 K) class Helium Refrigerator cum Liquefier (HRL) system. An accurate measurement of helium mass flow rate in different coils is required to ensure the uniform cooling of the cold mass in the entire range of operating temperature (300 K to 4.5 K) and pressure (0.9–0.4 MPa). To meet this requirement, indigenously designed and fabricated venturi meters are installed on 27 different coils of SST-1 SCMS. A VME based Data Acquisition System (DAS) has been developed and used to acquire the flow measurement data from different flowmeters. The details of the design of venturi meter, its different measurement and signal conditioning components, the data acquisition system and the mass flow rate calculation method are described in this paper. The mass flow rate measurement data from cryogenic acceptance and SST-1 magnet commissioning experiments are also presented and discussed in this paper.

Interannual Variability, Global Teleconnection, and Potential Predictability Associated with the Asian Summer Monsoon

Science.gov (United States)

Lau, K. M.; Kim, K. M.; Li, J. Y.

2001-01-01

In this Chapter, aspects of global teleconnections associated with the interannual variability of the Asian summer monsoon (ASM) are discussed. The basic differences in the basic dynamics of the South Asian Monsoon and the East Asian monsoon, and their implications on global linkages are discussed. Two teleconnection modes linking ASM variability to summertime precipitation over the continental North America were identified. These modes link regional circulation and precipitation anomalies over East Asia and continental North America, via coupled atmosphere-ocean variations over the North Pacific. The first mode has a large zonally symmetrical component and appears to be associated with subtropical jetstream variability and the second mode with Rossby wave dispersion. Both modes possess strong sea surface temperature (SST) expressions in the North Pacific. Results show that the two teleconnection modes may have its origin in intrinsic modes of sea surface temperature variability in the extratropical oceans, which are forced in part by atmospheric variability and in part by air-sea interaction. The potential predictability of the ASM associated with SST variability in different ocean basins is explored using a new canonical ensemble correlation prediction scheme. It is found that SST anomalies in tropical Pacific, i.e., El Nino, is the most dominant forcing for the ASM, especially over the maritime continent and eastern Australia. SST anomalies in the India Ocean may trump the influence from El Nino in western Australia and western maritime continent. Both El Nino, and North Pacific SSTs contribute to monsoon precipitation anomalies over Japan, southern Korea, northern and central China. By optimizing SST variability signals from the world ocean basins using CEC, the overall predictability of ASM can be substantially improved.

Impact of La Niña and La Niña Modoki on Indonesia rainfall variability

Science.gov (United States)

Hidayat, R.; Juniarti, MD; Ma’rufah, U.

2018-05-01

La Niña events are indicated by cooling SST in central and eastern equatorial Pacific. While La Niña Modoki occurrences are indicated by cooling SST in central Pacific and warming SST in western and eastern equatorial Pacific. These two events are influencing rainfall variability in several regions including Indonesia. The objective of this study is to analyse the impact of La Niña and La Niña Modoki on Indonesian rainfall variability. We found the Nino 3.4 index is highly correlated (r = -0.95) with Indonesian rainfall. Positive rainfall anomalies up to 200 mm/month occurred mostly in Indonesian region during La Niña events, but in DJF several areas of Sumatera, Kalimantan and eastern Indonesia tend to have negative rainfall. During La Niña Modoki events, positive rainfall anomaly (up to 50 mm/month) occurred in Sumatera Island, Kalimantan, Java and eastern Indonesia in DJF and up to 175 mm/month occurred only in Java Island in MAM season. La Niña events have strong cooling SST in central and eastern equatorial Pacific (-1.5°C) in DJF. While La Niña Modoki events warming SST occurred in western and eastern equatorial Pacific (0.75°C) and cooling SST in central Pacific (- 0.75°C) in DJF and MAM. Walker circulation in La Niña Modoki events (on DJF and MAM) showed strong convergence in eastern Pacific, and weak convergence in western Pacific (Indonesia).

Interactions of the tropical oceans. Rev.ed.

International Nuclear Information System (INIS)

Latif, M.; Barnett, T.P.

1994-01-01

We have investigated the interactions of the tropical oceans on interannual time scales by conducting a series of uncoupled atmospheric and oceanic general circulation experiments and hybrid coupled model simulations. Our results illustrate the key role of the El Nino/Southern Oscillation (ENSO) phenomenon in generating interannual variability in all three tropical ocean basins. Sea surface temperature (SST) anomalies in the tropical Pacific force via a changed atmospheric circulation SST anomalies of the same sign in the Indian Ocean and SST anomalies of the opposite sign in the Atlantic. However, although air-sea interactions in the Indian and Atlantic Oceans are much weaker than those in the Pacific, they contribute significantly to the variability in these two regions. The role of these air-sea interactions is mainly that of an amplifyer by which the ENSO induced signals are enhanced in ocean and atmosphere. This process is particularly important in the tropical Atlantic region. We investigated also whether ENSO is part of a zonally propagating ''wave'' which travels around the globe with a time scale of several years. Consistent with observations, the upper ocean heat content in the various numerical simulations seems to propagate slowly around the globe. SST anomalies in the Pacific Ocean introduce a global atmospheric response which in turn forces variations in the other tropical oceans. Since the different oceans exhibit different response characteristics to low-frequency wind changes, the individual tropical ocean responses can add up coincidentally to look like a global wave, and that appears to be the situation. In particular, no evidence is found that the Indian Ocean can significantly affect the ENSO cycle in the Pacific. Finally, the potential for climate forecasts in the Indian and Atlantic Oceans appears to be enhanced if one includes, in a coupled way, remote influences from the Pacific. (orig.)

Effect of attractive interactions on the water-like anomalies of a core-softened model potential.

Science.gov (United States)

Pant, Shashank; Gera, Tarun; Choudhury, Niharendu

2013-12-28

It is now well established that water-like anomalies can be reproduced by a spherically symmetric potential with two length scales, popularly known as core-softened potential. In the present study we aim to investigate the effect of attractive interactions among the particles in a model fluid interacting with core-softened potential on the existence and location of various water-like anomalies in the temperature-pressure plane. We employ extensive molecular dynamic simulations to study anomalous nature of various order parameters and properties under isothermal compression. Order map analyses have also been done for all the potentials. We observe that all the systems with varying depth of attractive wells show structural, dynamic, and thermodynamic anomalies. As many of the previous studies involving model water and a class of core softened potentials have concluded that the structural anomaly region encloses the diffusion anomaly region, which in turn, encloses the density anomaly region, the same pattern has also been observed in the present study for the systems with less depth of attractive well. For the systems with deeper attractive well, we observe that the diffusion anomaly region shifts toward higher densities and is not always enclosed by the structural anomaly region. Also, density anomaly region is not completely enclosed by diffusion anomaly region in this case.

Baking of SST-1 vacuum vessel modules and sectors

International Nuclear Information System (INIS)

Pathan, Firozkhan S; Khan, Ziauddin; Yuvakiran, Paravastu; George, Siju; Ramesh, Gattu; Manthena, Himabindu; Shah, Virendrakumar; Raval, Dilip C; Thankey, Prashant L; Dhanani, Kalpesh R; Pradhan, Subrata

2012-01-01

SST-1 Tokamak is a steady state super-conducting tokamak for plasma discharge of 1000 sec duration. The plasma discharge of such long time duration can be obtained by reducing the impurities level, which will be possible only when SST-1 vacuum chamber is pumped to ultra high vacuum. In order to achieve UHV inside the chamber, the baking of complete vacuum chamber has to be carried out during pumping. For this purpose the C-channels are welded inside the vacuum vessel. During baking of vacuum vessel, these welded channels should be helium leak tight. Further, these U-channels will be in accessible under operational condition of SST-1. So, it will not possible to repair if any leak is developed during experiment. To avoid such circumstances, a dedicated high vacuum chamber is used for baking of the individual vacuum modules and sectors before assembly so that any fault during welding of the channels will be obtained and repaired. This paper represents the baking of vacuum vessel modules and sectors and their temperature distribution along the entire surface before assembly.

Thermo hydraulic and quench propagation characteristics of SST-1 TF coil

Energy Technology Data Exchange (ETDEWEB)

Sharma, A.N., E-mail: ansharma@ipr.res.in [Institute for Plasma Research, Gandhinagar (India); Pradhan, S. [Institute for Plasma Research, Gandhinagar (India); Duchateau, J.L. [CEA Cadarache, 13108 St Paul lez Durance Cedex (France); Khristi, Y.; Prasad, U.; Doshi, K.; Varmora, P.; Patel, D.; Tanna, V.L. [Institute for Plasma Research, Gandhinagar (India)

2014-02-15

Highlights: • Details of SST-1 TF coils, CICC. • Details of SST-1 TF coil cold test. • Quench analysis of TF magnet. • Flow changes following quench. • Predictive analysis of assembled magnet system. - Abstract: SST-1 toroidal field (TF) magnet system is comprising of sixteen superconducting modified ‘D’ shaped TF coils. During single coil test campaigns spanning from June 10, 2010 till January 24, 2011; the electromagnetic, thermal hydraulic and mechanical performances of each TF magnet have been qualified at its respective nominal operating current of 10,000 A in either two-phase or supercritical helium cooling conditions. During the current charging experiments, few quenches have initiated either as a consequence of irrecoverable normal zones or being induced in some of the TF magnets. Quench evolution in the TF coils have been analyzed in detail in order to understand the thermal hydraulic and quench propagation characteristics of the SST-1 TF magnets. The same were also simulated using 1D code Gandalf. This paper elaborates the details of the analyses and the quench simulation results. A predictive quench propagation analysis of 16 assembled TF magnets system has also been reported in this paper.

Conditioning of SST-1 Tokamak Vacuum Vessel by Baking and Glow Discharge Cleaning

International Nuclear Information System (INIS)

Khan, Ziauddin; George, Siju; Semwal, Pratibha; Dhanani, Kalpeshkumar R.; Pathan, Firozkhan S.; Paravastu, Yuvakiran; Raval, Dilip C.; Babu, Gattu Ramesh; Khan, Mohammed Shoaib; Pradhan, Subrata

2016-01-01

Highlights: • SST-1 Tokamak was successfully commissioned. • Vacuum vessel was pumped down to 4.5 × 10"–"8 mbar after baking and continuous GDC. • GDC reduced the water vapour by additional 57% while oxygen was reduced by 50%. • Under this condition, an initial plasma breakdown with current of 40 kA for 75 ms was achieved. - Abstract: Steady-state Superconducting Tokamak (SST-1) vacuum vessel (VV) adopts moderate baking at 110 ± 10 °C and the limiters baking at 250 ± 10 °C for ∼ 200 h followed by glow discharge cleaning in hydrogen (GDC-H) with 0.15 A/m"2 current density towards its conditioning prior to plasma discharge experiment. The baking in SST-1 reduces the water (H_2O) vapor by 95% and oxygen (O_2) by 60% whereas the GDC reduces the water vapor by an additional 57% and oxygen by another 50% as measured with residual gas analyzer. The minimum breakdown voltage for H-GDC in SST-1 tokamak was experimentally observed to 300 V at 8 mbar cm. As a result of these adherences, SST-1 VV achieves an ultimate of 4.5 × 10"−"8 mbar with two turbo-molecular pumps with effective pumping speed of 3250 l/s. In the last campaign, SST-1 has achieved successful plasma breakdown, impurity burn through and a plasma current of ∼ 40 kA for 75 ms.

Conditioning of SST-1 Tokamak Vacuum Vessel by Baking and Glow Discharge Cleaning

Energy Technology Data Exchange (ETDEWEB)

Khan, Ziauddin, E-mail: ziauddin@ipr.res.in; George, Siju; Semwal, Pratibha; Dhanani, Kalpeshkumar R.; Pathan, Firozkhan S.; Paravastu, Yuvakiran; Raval, Dilip C.; Babu, Gattu Ramesh; Khan, Mohammed Shoaib; Pradhan, Subrata

2016-02-15

Highlights: • SST-1 Tokamak was successfully commissioned. • Vacuum vessel was pumped down to 4.5 × 10{sup –8} mbar after baking and continuous GDC. • GDC reduced the water vapour by additional 57% while oxygen was reduced by 50%. • Under this condition, an initial plasma breakdown with current of 40 kA for 75 ms was achieved. - Abstract: Steady-state Superconducting Tokamak (SST-1) vacuum vessel (VV) adopts moderate baking at 110 ± 10 °C and the limiters baking at 250 ± 10 °C for ∼ 200 h followed by glow discharge cleaning in hydrogen (GDC-H) with 0.15 A/m{sup 2} current density towards its conditioning prior to plasma discharge experiment. The baking in SST-1 reduces the water (H{sub 2}O) vapor by 95% and oxygen (O{sub 2}) by 60% whereas the GDC reduces the water vapor by an additional 57% and oxygen by another 50% as measured with residual gas analyzer. The minimum breakdown voltage for H-GDC in SST-1 tokamak was experimentally observed to 300 V at 8 mbar cm. As a result of these adherences, SST-1 VV achieves an ultimate of 4.5 × 10{sup −8} mbar with two turbo-molecular pumps with effective pumping speed of 3250 l/s. In the last campaign, SST-1 has achieved successful plasma breakdown, impurity burn through and a plasma current of ∼ 40 kA for 75 ms.

Geoid and gravity anomaly data of conjugate regions of Bay of Bengal and Enderby Basin: New constraints on breakup and early spreading history between India and Antarctica

Digital Repository Service at National Institute of Oceanography (India)

Krishna, K.S.; Michael, L.; Bhattacharyya, R.; Majumdar, T.J.

the anomalies. Since the magnetic anomalies in the western Enderby Basin have lower amplitude, Gaina et al. (2007) could not identify the anomalies with confidence and found difficulty to correlate the spreading history with that of the central and eastern... Geoid and gravity anomaly data of conjugate regions of Bay of Bengal and Enderby Basin – new constraints on breakup and early spreading history between India and Antarctica K.S. Krishna*, Laju Michael National Institute of Oceanography, Council...

FLAMMABLE GAS DIFFUSION THROUGH SINGLE SHELL TANK (SST) DOMES

Energy Technology Data Exchange (ETDEWEB)

MEACHAM, J.E.

2003-11-10

This report quantified potential hydrogen diffusion through Hanford Site Single-Shell tank (SST) domes if the SSTs were hypothetically sealed airtight. Results showed that diffusion would keep headspace flammable gas concentrations below the lower flammability limit in the 241-AX and 241-SX SST. The purpose of this document is to quantify the amount of hydrogen that could diffuse through the domes of the SSTs if they were hypothetically sealed airtight. Diffusion is assumed to be the only mechanism available to reduce flammable gas concentrations. The scope of this report is limited to the 149 SSTs.

Waterlike anomalies in a two-dimensional core-softened potential

Science.gov (United States)

Bordin, José Rafael; Barbosa, Marcia C.

2018-02-01

We investigate the structural, thermodynamic, and dynamic behavior of a two-dimensional (2D) core-corona system using Langevin dynamics simulations. The particles are modeled by employing a core-softened potential which exhibits waterlike anomalies in three dimensions. In previous studies in a quasi-2D system a new region in the pressure versus temperature phase diagram of structural anomalies was observed. Here we show that for the two-dimensional case two regions in the pressure versus temperature phase diagram with structural, density, and diffusion anomalies are observed. Our findings indicate that, while the anomalous region at lower densities is due the competition between the two length scales in the potential at higher densities, the anomalous region is related to the reentrance of the melting line.

Subseasonal Reversal of East Asian Surface Temperature Variability in Winter 2014/15

Science.gov (United States)

Xu, Xinping; Li, Fei; He, Shengping; Wang, Huijun

2018-06-01

Although there has been a considerable amount of research conducted on the East Asian winter-mean climate, subseasonal surface air temperature (SAT) variability reversals in the early and late winter remain poorly understood. In this study, we focused on the recent winter of 2014/15, in which warmer anomalies dominated in January and February but colder conditions prevailed in December. Moreover, Arctic sea-ice cover (ASIC) in September-October 2014 was lower than normal, and warmer sea surface temperature (SST) anomalies occurred in the Niño4 region in winter, together with a positive Pacific Decadal Oscillation (PDO|+) phase. Using observational data and CMIP5 historical simulations, we investigated the PDO|+ phase modulation upon the winter warm Niño4 phase (autumn ASIC reduction) influence on the subseasonal SAT variability of East Asian winter. The results show that, under a PDO|+ phase modulation, warm Niño4 SST anomalies are associated with a subseasonal delay of tropical surface heating and subsequent Hadley cell and Ferrel cell intensification in January-February, linking the tropical and midlatitude regions. Consistently, the East Asian jet stream (EAJS) is significantly decelerated in January-February and hence promotes the warm anomalies over East Asia. Under the PDO|+ phase, the decrease in ASIC is related to cold SST anomalies in the western North Pacific, which increase the meridional temperature gradient and generate an accelerated and westward-shifted EAJS in December. The westward extension of the EAJS is responsible for the eastward-propagating Rossby waves triggered by declining ASIC and thereby favors the connection between ASIC and cold conditions over East Asia.

AGCM hindcasts with SST and other forcings: Responses from global to agricultural scales

Science.gov (United States)

Shah, Kathryn Pierce; Rind, David; Druyan, Leonard; Lonergan, Patrick; Chandler, Mark

2000-08-01

Multiple realizations of the 1969-1998 time period have been simulated by the GISS AGCM to explore its responsiveness to accumulated forcings, particularly over sensitive agricultural regions. A microwave radiative transfer postprocessor has produced the AGCM lower tropospheric, tropospheric, and lower stratospheric brightness temperature (Tb) time series for correlations with microwave sounding unit (MSU) time series. AGCM regional surface air temperature and precipitation were also correlated with GISTEMP temperature data and with rain gage data. Seven realizations by the AGCM were forced solely by observed sea surface temperatures. Subsequent runs hindcast January 1969 through April 1998 with an accumulation of forcings: observed sea surface temperatures (SSTs), greenhouse gases, stratospheric volcanic aerosols, stratospheric and tropospheric ozone, and tropospheric sulfate and black carbon aerosols. Lower stratospheric Tb correlations between the AGCM and the MSU for 1979-1998 reached as high as 0.93 globally given SST, greenhouse gases, volcanic aerosol, and stratospheric ozone forcings. Midtropospheric Tb correlations reached as high as 0.66 globally and 0.84 across the equatorial, 20°S-20°N band. Oceanic lower tropospheric Tb correlations were less high at 0.59 globally and 0.79 across the equatorial band. Of the sensitive agricultural areas considered, Nordeste in northeastern Brazil was simulated best with midtropospheric Tb correlations up to 0.80. The two other agricultural regions, in Africa and in the northern midlatitudes, suffered from higher levels of non-SST-induced variability. Zimbabwe had a maximum midtropospheric correlation of 0.54, while the U.S. Corn Belt reached only 0.25. Hindcast surface temperatures and precipitation were also correlated with observations, up to 0.46 and 0.63, respectively, for Nordeste. Correlations between AGCM and observed time series improved with addition of certain atmospheric forcings in zonal bands but not in

Unsteady Simulations of the Flow in a Channel Flow and a Ventilated Room Using the SST-SAS Model

DEFF Research Database (Denmark)

Davidson, Lars; Nielsen, Peter V.

The SAS model (Scale Adapted Simulation) was invented by Menter and his co-workers. The idea behind the SST-SAS model is to add an additional production term - the SAS term - in the w equation which is sensitive to resolved (i.e. unsteady) fluctuations. In regions where the flow is on the limit...

Climatic variability of river outflow in the Pantanal region and the influence of sea surface temperature

Science.gov (United States)

Silva, Carlos Batista; Silva, Maria Elisa Siqueira; Ambrizzi, Tércio

2017-07-01

This paper investigates possible linear relationships between climate, hydrology, and oceanic surface variability in the Pantanal region (in South America's central area), over interannual and interdecadal time ranges. In order to verify the mentioned relations, lagged correlation analysis and linear adjustment between river discharge at the Pantanal region and sea surface temperature were used. Composite analysis for atmospheric fields, air humidity flux divergence, and atmospheric circulation at low and high levels, for the period between 1970 and 2003, was analyzed. Results suggest that the river discharge in the Pantanal region is linearly associated with interdecadal and interannual oscillations in the Pacific and Atlantic oceans, making them good predictors to continental hydrological variables. Considering oceanic areas, 51 % of the annual discharge in the Pantanal region can be linearly explained by mean sea surface temperature (SST) in the Subtropical North Pacific, Tropical North Pacific, Extratropical South Pacific, and Extratropical North Atlantic over the period. Considering a forecast approach in seasonal scale, 66 % of the monthly discharge variance in Pantanal, 3 months ahead of SST, is explained by the oceanic variables, providing accuracy around 65 %. Annual discharge values in the Pantanal region are strongly related to the Pacific Decadal Oscillation (PDO) variability (with 52 % of linear correlation), making it possible to consider an interdecadal variability and a consequent subdivision of the whole period in three parts: 1st (1970-1977), 2nd (1978-1996), and 3rd (1997-2003) subperiods. The three subperiods coincide with distinct PDO phases: negative, positive, and negative, respectively. Convergence of humidity flux at low levels and the circulation pattern at high levels help to explain the drier and wetter subperiods. During the wetter 2nd subperiod, the air humidity convergence at low levels is much more evident than during the other two

MHD mode evolutions prior to minor and major disruptions in SST-1 plasma

Energy Technology Data Exchange (ETDEWEB)

Dhongde, Jasraj; Pradhan, Subrata, E-mail: pradhan@ipr.res.in; Bhandarkar, Manisha

2017-01-15

Highlights: • Observation of different regimes of MHD phenomena in SST-1 plasma. • MHD mode (m/n = 1/1, m/n = 2/1) evolutions prior to minor and major disruptions in SST-1 plasma. • MHD mode characteristics such as mode frequency, mode number, island width etc. in different regimes. - Abstract: Steady State Superconducting Tokamak (SST-1) is a medium size Tokamak (R{sub 0} = 1.1 m, a = 0.2 m, B{sub T} = 1.5T, Ip ∼ 110 kA) in operation at the Institute for Plasma Research, India. SST-1 uniquely experiments large aspect ratio (∼5.5) plasma in different operation regimes. In these experiments, repeatable characteristic MHD phenomena have been consistently observed. As the large aspect ratio plasma pulse progresses, these MHD phenomena display minor-major disruptions ably indicated in Mirnov oscillations, Mirnov oscillations with saw teeth and locked modes etc. Even though somewhat similar observations have been found in some other machines, these observations are found for the first time in large aspect ratio plasma of SST-1. This paper elaborates the magnetic field perturbations and mode evolutions due to MHD activities from Mirnov coils (poloidal and toroidal), Soft X-ray diagnostics, ECE diagnostics etc. This work further, for the first time reports quantitatively different regimes of MHD phenomena observed in SST-1 plasma, their details of mode evolutions characteristics as well as the subsequently observed minor, major disruptions supported with the physical explanations. This study will help developing disruption mitigation and avoidance scenarios for having better confinement plasma experiments.

Regional drought in the southern of South America: physical aspects Seca regional no sul da América do Sul: aspectos físicos

Directory of Open Access Journals (Sweden)

Juan Leonidas Minetti

2010-03-01

Full Text Available From the indices of monthly and annual climatic drought in six regions in southern South America and their associations with seventeen predictors, the probable physical causes of droughts are analyzed. These indices are used in operational climate monitoring and describe the atmospheric temperature and sea surface temperature (SST near South America. Subtropical anticyclone activity over both coasts of South America is one of the main predictors, together with its interaction with the continental depression and SST at the coast of Brazil. The highest predictability concentrates in November-December-May and the lowest in March, June and August. In the sub regional scale, the main predictors respond to atmospheric pressure anomalies in the Atlantic Ocean for Argentinean Northwest (NOA, SST in the Brazilian coast for Argentinean Northeast (NEA, anticyclonic conditions over the Pacific and Atlantic for the Central West (CO, the latter and their interaction with the continental depression for Humid Pampa (PH, anticyclonic activity over the Pacific for the Patagonia (PAT and trans cordillera circulation for Central Chile and Comahue (CHI.As causas físicas prováveis das secas em seis regiões no sul da América do Sul são analisadas, através de índices da seca climática mensal e em suas associações com dezessete preditores. Esses indices são usados no monitoramento operacional do clima, e descrevem a temperatura atmosférica e a temperatura de superfície do mar (TSM perto de América do Sul. A atividade do anticiclone subtropical sobre ambas as costas de América do Sul é um dos preditores principais, junto com sua interação com a depressão continental e a SST na costa do Brasil. A previsibilidade mais elevada concentra-se nos meses Novembro-Dezembro-Maio e a mais baixa, em março, junho e agosto. Na escala regional secundária, os principais preditores respondem às anomalias da pressão atmosférica sobre o Oceano Atlântico para

Fortnightly atmospheric tides forced by spring and neap tides in coastal waters.

Science.gov (United States)

Iwasaki, Shinsuke; Isobe, Atsuhiko; Miyao, Yasuyuki

2015-05-18

The influence of sea surface temperature (SST) on atmospheric processes over the open ocean has been well documented. However, atmospheric responses to SST in coastal waters are poorly understood. Oceanic stratification (and consequently, SST) in coastal waters largely depends on the fortnightly spring-neap tidal cycle, because of variations in vertical tidal mixing. Here we investigate how changes in SST during the fortnightly tidal cycle affect the lower-level atmosphere over the Seto Inland Sea, Japan. We use a combination of in situ measurements, satellite observations and a regional atmospheric model. We find that the SST in summer shows cool (warm) anomalies over most of the inland sea during spring (neap) tides. Additionally, surface air temperature is positively correlated with the SST as it varies during the fortnightly tidal cycle. Moreover, the fortnightly spring-neap cycle also influences the surface wind speed because the atmospheric boundary layer becomes stabilized or destabilized in response to the difference between air temperature and SST.

The role of the tropical West Pacific in the extreme northern hemisphere winter of 2013/14

Science.gov (United States)

Watson, Peter; Weisheimer, Antje; Knight, Jeff; Palmer, Tim

2016-04-01

In the 2013/14 winter, the eastern USA was exceptionally cold, the Bering Strait region was exceptionally warm, California was in the midst of drought and the UK suffered severe flooding. It has been suggested that elevated SSTs in the tropical West Pacific (TWPAC) were partly to blame due to their producing a Rossby wavetrain that propagated into the extratropics. We find that seasonal forecasts with the tropical atmosphere relaxed towards a reanalysis give 2013/14 winter-mean anomalies with strong similarities to those observed in the Northern Hemisphere, indicating that low-latitude anomalies had a role in the development of the extremes. Relaxing just the TWPAC produces a strong wavetrain over the North Pacific and North America in January, but not in the winter-mean. This suggests that anomalies in this region alone had a large influence, but cannot explain the extremes through the whole winter. We also examine the response to applying the observed TWPAC SST anomalies in two atmospheric general circulation models. We find that this does produce winter-mean anomalies in the North Pacific and North America resembling those observed, but that the tropical forcing of Rossby waves due to the applied SST anomalies appears stronger than that in reanalysis, except in January. Therefore both experiments indicate that the TWPAC influence was important, but the true strength of the TWPAC influence is uncertain. None of the experiments indicate a strong systematic impact of the TWPAC anomalies on Europe.

GRASS-SST, Fission Products Gas Release and Fuel Swelling in Steady-State and Transients

International Nuclear Information System (INIS)

Zawadzki, S.

2001-01-01

1 - Description of program or function: GRASS-SST is a comprehensive, mechanistic model for the prediction of fission-gas behaviour in UO 2 -base fuels during steady-state and transient conditions. GRASS-SST treats fission-gas release and fuel swelling on an equal basis and simultaneously treats all major mechanisms that influence fission-gas behaviour. Models are included for intra- and inter-granular fission-gas bubble behaviour as well as a mechanistic description of the role of grain-edge inter-linked porosity on fission-gas release and swelling. GRASS-SST calculations include the effects of gas production from fissioning uranium atoms, bubble nucleation, a realistic equation of state for xenon, lattice bubble diffusivities based on experimental observations, bubble migration, bubble coalescence, re-solution, temperature and temperature gradients, inter-linked porosity, and fission-gas interaction with structural defects (dislocations and grain boundaries) on both the distribution of fission-gas within the fuel and on the amount of fission-gas released from the fuel. GRASS-SST includes the effects of the degree of nonequilibrium in the UO 2 lattice on fission-gas bubble mobility and bubble coalescence and also accounts for the observed formation of grain-surface channels. GRASS-SST also includes mechanistic models for grain-growth/grain boundary sweeping and for the behaviour of fission gas during liquefaction/dissolution and fuel melting conditions. 2 - Method of solution: A system of coupled equations for the evolution of the fission-gas bubble-size distributions in the lattice, on dislocations, on grain faces, and grain edges is derived based on the GRASS-SST models. Given a set of operating conditions, GRASS-SST calculates the bubble radii for the size classes of bubbles under consideration using a realistic equation of state for xenon as well as a generalised capillary relation. 3 - Restrictions on the complexity of the problem: Maxima of : 1 axial section

Lunar Bouguer gravity anomalies - Imbrian age craters

Science.gov (United States)

Dvorak, J.; Phillips, R. J.

1978-01-01

The Bouguer gravity of mass anomalies associated with four Imbrian age craters, analyzed in the present paper, are found to differ considerably from the values of the mass anomalies associated with some young lunar craters. Of the Imbrian age craters, only Piccolomini exhibits a negative gravity anomaly (i.e., a low density region) which is characteristic of the young craters studied. The Bouguer gravity anomalies are zero for each of the remaining Imbrian age craters. Since, Piccolomini is younger, or at least less modified, than the other Imbrian age craters, it is suggested that the processes responsible for the post-impact modification of the Imbrian age craters may also be responsible for removing the negative mass anomalies initially associated with these features.

Separating the Effects of Tropical Atlantic and Pacific SST-driven Climate Variability on Amazon Carbon Exchange

Science.gov (United States)

Liptak, J.; Keppel-Aleks, G.

2016-12-01

Amazon forests store an estimated 25% percent of global terrestrial carbon per year1, 2, but the responses of Amazon carbon uptake to climate change is highly uncertain. One source of this uncertainty is tropical sea surface temperature variability driven by teleconnections. El Nino-Southern Oscillation (ENSO) is a key driver of year-to-year Amazon carbon exchange, with associated temperature and precipitation changes favoring net carbon storage in La Nina years, and net carbon release during El Nino years3. To determine how Amazon climate and terrestrial carbon fluxes react to ENSO alone and in concert with other SST-driven teleconnections such as the Atlantic Multidecadal Oscillation (AMO), we force the atmosphere (CAM5) and land (CLM4) components of the CESM(BGC) with prescribed monthly SSTs over the period 1950—2014 in a Historical control simulation. We then run an experiment (PAC) with time-varying SSTs applied only to the tropical equatorial Pacific Ocean, and repeating SST seasonal cycle climatologies elsewhere. Limiting SST variability to the equatorial Pacific indicates that other processes enhance ENSO-driven Amazon climate anomalies. Compared to the Historical control simulation, warming, drying and terrestrial carbon loss over the Amazon during El Nino periods are lower in the PAC simulation, especially prior to 1990 during the cool phase of the AMO. Cooling, moistening, and net carbon uptake during La Nina periods are also reduced in the PAC simulation, but differences are greater after 1990 during the warm phase of the AMO. By quantifying the relationships among climate drivers and carbon fluxes in the Historical and PAC simulations, we both assess the sensitivity of these relationships to the magnitude of ENSO forcing and quantify how other teleconnections affect ENSO-driven Amazon climate feedbacks. We expect that these results will help us improve hypotheses for how Atlantic and Pacific climate trends will affect future Amazon carbon carbon

Comparing soil moisture anomalies from multiple independent sources over different regions across the globe

Science.gov (United States)

Cammalleri, Carmelo; Vogt, Jürgen V.; Bisselink, Bernard; de Roo, Ad

2017-12-01

Agricultural drought events can affect large regions across the world, implying the need for a suitable global tool for an accurate monitoring of this phenomenon. Soil moisture anomalies are considered a good metric to capture the occurrence of agricultural drought events, and they have become an important component of several operational drought monitoring systems. In the framework of the JRC Global Drought Observatory (GDO, eu/gdo/" target="_blank">http://edo.jrc.ec.europa.eu/gdo/), the suitability of three datasets as possible representations of root zone soil moisture anomalies has been evaluated: (1) the soil moisture from the Lisflood distributed hydrological model (namely LIS), (2) the remotely sensed Land Surface Temperature data from the MODIS satellite (namely LST), and (3) the ESA Climate Change Initiative combined passive/active microwave skin soil moisture dataset (namely CCI). Due to the independency of these three datasets, the triple collocation (TC) technique has been applied, aiming at quantifying the likely error associated with each dataset in comparison to the unknown true status of the system. TC analysis was performed on five macro-regions (namely North America, Europe, India, southern Africa and Australia) detected as suitable for the experiment, providing insight into the mutual relationship between these datasets as well as an assessment of the accuracy of each method. Even if no definitive statement on the spatial distribution of errors can be provided, a clear outcome of the TC analysis is the good performance of the remote sensing datasets, especially CCI, over dry regions such as Australia and southern Africa, whereas the outputs of LIS seem to be more reliable over areas that are well monitored through meteorological ground station networks, such as North America and Europe. In a global drought monitoring system, the results of the error analysis are used to design a weighted-average ensemble system that exploits the advantages of

Data reduction and tying in regional gravity surveys—results from a new gravity base station network and the Bouguer gravity anomaly map for northeastern Mexico

Science.gov (United States)

Hurtado-Cardador, Manuel; Urrutia-Fucugauchi, Jaime

2006-12-01

Since 1947 Petroleos Mexicanos (Pemex) has conducted oil exploration projects using potential field methods. Geophysical exploration companies under contracts with Pemex carried out gravity anomaly surveys that were referred to different floating data. Each survey comprises observations of gravity stations along highways, roads and trails at intervals of about 500 m. At present, 265 separate gravimeter surveys that cover 60% of the Mexican territory (mainly in the oil producing regions of Mexico) are available. This gravity database represents the largest, highest spatial resolution information, and consequently has been used in the geophysical data compilations for the Mexico and North America gravity anomaly maps. Regional integration of gravimeter surveys generates gradients and spurious anomalies in the Bouguer anomaly maps at the boundaries of the connected surveys due to the different gravity base stations utilized. The main objective of this study is to refer all gravimeter surveys from Pemex to a single new first-order gravity base station network, in order to eliminate problems of gradients and spurious anomalies. A second objective is to establish a network of permanent gravity base stations (BGP), referred to a single base from the World Gravity System. Four regional loops of BGP covering eight States of Mexico were established to support the tie of local gravity base stations from each of the gravimeter surveys located in the vicinity of these loops. The third objective is to add the gravity constants, measured and calculated, for each of the 265 gravimeter surveys to their corresponding files in the Pemex and Instituto Mexicano del Petroleo database. The gravity base used as the common datum is the station SILAG 9135-49 (Latin American System of Gravity) located in the National Observatory of Tacubaya in Mexico City. We present the results of the installation of a new gravity base network in northeastern Mexico, reference of the 43 gravimeter surveys

Air-Sea Interaction in the Somali Current Region

Science.gov (United States)

Jensen, T. G.; Rydbeck, A.

2017-12-01

The western Indian Ocean is an area of high eddy-kinetic energy generated by local wind-stress curl, instability of boundary currents as well as Rossby waves from the west coast of India and the equatorial wave guide as they reflect off the African coast. The presence of meso-scale eddies and coastal upwelling during the Southwest Monsoon affects the air-sea interaction on those scales. The U.S. Navy's Coupled Ocean-Atmosphere Mesoscale Prediction System (COAMPS) is used to understand and quantify the surface flux, effects on surface waves and the role of Sea Surface Temperature anomalies on ocean-atmosphere coupling in that area. The COAMPS atmosphere model component with 9 km resolution is fully coupled to the Navy Coastal Ocean Model (NCOM) with 3.5 km resolution and the Simulating WAves Nearshore (SWAN) wave model with 10 km resolution. Data assimilation using a 3D-variational approach is included in hindcast runs performed daily since June 1, 2015. An interesting result is that a westward jet associated with downwelling equatorial Rossy waves initiated the reversal from the southward Somali Current found during the northeast monsoon to a northward flow in March 2016 more than a month before the beginning of the southwest monsoon. It is also found that warm SST anomalies in the Somali Current eddies, locally increase surface wind speed due to an increase in the atmospheric boundary layer height. This results in an increase in significant wave height and also an increase in heat flux to the atmosphere. Cold SST anomalies over upwelling filaments have the opposite impacts on air-sea fluxes.

Tropical-extratropical climate interaction as revealed in idealized coupled climate model experiments

Energy Technology Data Exchange (ETDEWEB)

Yang, Haijun [Peking University, Department of Atmospheric Science and Laboratory for Severe Storm and Flood Disasters, School of Physics, Beijing (China); Liu, Zhengyu [University of Wisconsin-Madison, Center for Climatic Research and Department of the Atmospheric and Oceanic Sciences, Madison, WI (United States)

2005-06-01

Tropical-extratropical climate interactions are studied by idealized experiments with a prescribed 2 C SST anomaly at different latitude bands in a coupled climate model. Instead of focusing on intrinsic climate variability, this work investigates the mean climate adjustment to remote external forcing. The extratropical impact on tropical climate can be as strong as the tropical impact on extratropical climate, with the remote sea surface temperature (SST) response being about half the magnitude of the imposed SST change in the forcing region. The equatorward impact of extratropical climate is accomplished by both the atmospheric bridge and the oceanic tunnel. About two-thirds of the tropical SST change comes from the atmospheric bridge, while the remaining one-third comes from the oceanic tunnel. The equatorial SST increase is first driven by the reduced latent heat flux and the weakened poleward surface Ekman transport, and then enhanced by the decrease in subtropical cells' strength and the equatorward subduction of warm anomalies. In contrast, the poleward impact of tropical climate is accomplished mainly by the atmospheric bridge, which is responsible for extratropical temperature changes in both the surface and subsurface. Sensitivity experiments also show the dominant role of the Southern Hemisphere oceans in the tropical climate change. (orig.)

Interannual SST Variability in the Japan/East Sea and Relationship with Environmental Variables

Science.gov (United States)

2006-01-01

Soya Strait (SS), and Tartar Strait (TTS). (b) Regional geography. Interannual SST Variability in the Japan/East Sea 117 200 interruptions due to...caused by differential seasonal forcing. During the summer strong solar radiation penetrates into the entire Longitude(oE) La tit ud e( o N ) 50 50 100...1988.6 1988.8 1989 1989.2 1989.4 1989.6 1989.8 1990 1990.2 -3 -2 -1 0 1 2 3 Time(year) Te m pe ra tu re (o C ) Longitude(oE) La tit ud e( o N ) (a) 5

Overview of time synchronization system of steady state superconducting tokamak SST-1

Energy Technology Data Exchange (ETDEWEB)

Kumar, A., E-mail: aveg@ipr.res.in; Masand, H.; Dhongde, J.; Patel, K.; Mahajan, K.; Gulati, H.; Bhandarkar, M.; Chudasama, H.; Pradhan, S.

2016-11-15

The Steady State Superconducting Tokamak (SST-1) consists of many distributed and heterogeneous plant/experiment systems viz. Water-Cooling, Power Supplies, Cryogenics, Vacuum, Magnets, Auxiliary-Heating sources, Diagnostics, Front End Electronics (FEE) & Data Acquisition systems, having their own data acquisition & control systems and control & monitor by Central Control System (CCS) during the machine operation. With distributed computing and interdependent systems, it is essential that all the data/event acquired must be with disciplined & precise time-base, so as to make the co-relation of the data/event from various plant and experiment systems easy. Hence it is important to have accurate and precise Time Synchronization in place. The two systems fulfill the requirement of the time synchronization in SST-1. The VME based Timing System (TS) provides synchronization amongst various experiment systems during the plasma discharges and works as discharge control system (DCS) while the GPS based Time Synchronization System (TSS) caters the requirement of synchronization during the continuous operation of various plant systems by feeding a central clock to all the plant systems. This paper presents the Time Synchronization System of SST-1, the results of the integrated testing and engineering validation with various SST-1 subsystems.

Understanding the predictability of seasonal precipitation over northeast Brazil

Science.gov (United States)

Misra, Vasubandhu

2006-05-01

Using multiple long-term simulations of the Center for Ocean-Land-Atmosphere Studies (COLA) atmospheric general circulation model (AGCM) forced with observed sea surface temperature (SST), it is shown that the model has high skill in simulating the February-March-April (FMA) rainy season over northeast Brazil (Nordeste). Separate sensitivity experiments conducted with the same model that entails suppression of all variability except for the climatological annual cycle in SST over the Pacific and Atlantic Oceans reveal that this skill over Nordeste is sensitive to SST anomalies in the tropical Atlantic Ocean. However, the spatial pattern of SST anomalies in the tropical Atlantic Ocean that correlate with FMA Nordeste rainfall are in fact a manifestation of El Niño Southern Oscillation (ENSO) phenomenon in the Pacific Ocean. This study also analyzes the failure of the COLA AGCM in capturing the correct FMA precipitation anomalies over Nordeste in several years of the simulation. It is found that this failure occurs when the SST anomalies over the northern tropical Atlantic Ocean are large and not significantly correlated with contemporaneous SST anomalies over the eastern Pacific Ocean. In two of the relatively large ENSO years when the model failed to capture the correct signal of the interannual variability of precipitation over Nordeste, it was found that the meridional gradient of SST anomalies over the tropical Atlantic Ocean was inconsistent with the canonical development of ENSO. The analysis of the probabilistic skill of the model revealed that it has more skill in predicting flood years than drought. Furthermore, the model has no skill in predicting normal seasons. These model features are consistent with the model systematic errors.

GHRSST Level 4 Denmark DMI Global SST:1

Data.gov (United States)

National Aeronautics and Space Administration — The L4 analysis is based upon nighttime GHRSST L2P subskin SST observations from several satellites and instruments such as: AMSRE, ATS_NR_2P, AVHRR18_G,...

Exploratory and spatial data analysis (EDA-SDA) for determining regional background levels and anomalies of potentially toxic elements in soils from Catorce-Matehuala, Mexico

Science.gov (United States)

Chiprés, J.A.; Castro-Larragoitia, J.; Monroy, M.G.

2009-01-01

The threshold between geochemical background and anomalies can be influenced by the methodology selected for its estimation. Environmental evaluations, particularly those conducted in mineralized areas, must consider this when trying to determinate the natural geochemical status of a study area, quantifying human impacts, or establishing soil restoration values for contaminated sites. Some methods in environmental geochemistry incorporate the premise that anomalies (natural or anthropogenic) and background data are characterized by their own probabilistic distributions. One of these methods uses exploratory data analysis (EDA) on regional geochemical data sets coupled with a geographic information system (GIS) to spatially understand the processes that influence the geochemical landscape in a technique that can be called a spatial data analysis (SDA). This EDA-SDA methodology was used to establish the regional background range from the area of Catorce-Matehuala in north-central Mexico. Probability plots of the data, particularly for those areas affected by human activities, show that the regional geochemical background population is composed of smaller subpopulations associated with factors such as soil type and parent material. This paper demonstrates that the EDA-SDA method offers more certainty in defining thresholds between geochemical background and anomaly than a numeric technique, making it a useful tool for regional geochemical landscape analysis and environmental geochemistry studies.

Long range forecasting of summer monsoon rainfall from SST in the central equatorial Indian Ocean

Digital Repository Service at National Institute of Oceanography (India)

Sadhuram, Y; Murthy, T.V.R.

of summer monsoon rainfall from SST in the central equatorial Indian ocean Y. Sadhuram and T. V. Ramana Murthy National Institute of Oceanography, Regional Centre, 176, Lawson's Bay Colony, . Visakhapatnam-530017 ABSTRACT Severalprediction tedmiques have... and droughts associated with strong and weak monsoons greatly influence the economy of the country. Most of the droughts and floods are associated with EI-Nino and La- Nina respectively (Webster andYang3 and krishna Kumar et al\\. The relationship between ENSO...

Singlet deflected anomaly/gauge mediation

International Nuclear Information System (INIS)

Blas, J. de; Delgado, A.

2012-01-01

We study an extension of the standard anomaly/gauge mediation scenario where the messenger fields have direct interactions with an extra gauge singlet. This realizes a phenomenologically viable NMSSM-like scenario free of the μ-b μ problem. Current cosmological constraints imply a small size for the anomaly-mediation contributions, unless some source of R-parity violation is permitted. In the latter case the allowed regions in the parameter space can be substantially larger than in the corresponding gauge-mediation scenario.

COBE-SST2 Sea Surface Temperature and Ice

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A new sea surface temperature (SST) analysis on a centennial time scale is presented. The dataset starts in 1850 with monthly 1x1 means and is periodically updated....

Atmospheric Simulations Using OGCM-Assimilation SST: Influence of the Wintertime Japan Sea on Monthly Precipitation

Directory of Open Access Journals (Sweden)

Masaru Yamamoto Naoki Hirose

2010-01-01

Full Text Available Temperature data for the Japan Sea obtained from ocean data assimilation modeling is applied to atmospheric simulations of monthly precipitation for January 2005. Because the volume of flow of the Tsushima Warm Current was large during the winter season, the sea surface temperature (SST and coastal precipitation were higher in comparison with those in 2003. In order to evaluate influence of SST on monthly precipitation, we use surface temperatures of the Japan Sea in 2003 and 2005 for comparative simulations of precipitation for January 2005. The precipitation in experiment C (using cool SST data in 2003 is smaller than that in experiment W (using warm SST data in 2005 in a large part of the sea area, since the small evaporation results from the low SST over the upstream area of northwesterly winter monsoon. In the domain of 33.67 - 45.82°N and 125.89 - 142.9°E, the averaged evaporation and precipitation in experiment C are 10% and 13% smaller than those in experiment W, respectively. About half of the difference between the precipitations observed for January 2003 and 2005 in a heavy snow area is equal to the difference between the two simulations. Our results show that the mesoscale SST difference between 2003 and 2005 is related to the local difference of monthly precipitation.

Regional magnetic anomalies, crustal strength, and the location of the northern Cordilleran fold-and-thrust belt

Science.gov (United States)

Saltus, R.W.; Hudson, T.L.

2007-01-01

The northern Cordilleran fold-and-thrust belt in Canada and Alaska is at the boundary between the broad continental margin mobile belt and the stable North American craton. The fold-and-thrust belt is marked by several significant changes in geometry: cratonward extensions in the central Yukon Territory and northeastern Alaska are separated by marginward re-entrants. These geometric features of the Cordilleran mobile belt are controlled by relations between lithospheric strength and compressional tectonic forces developed along the continental margin. Regional magnetic anomalies indicate deep thermal and compositional characteristics that contribute to variations in crustal strength. Our detailed analysis of one such anomaly, the North Slope deep magnetic high, helps to explain the geometry of the fold-and-thrust front in northern Alaska. This large magnetic anomaly is inferred to reflect voluminous mafic magmatism in an old (Devonian?) extensional domain. The presence of massive amounts of malic material in the lower crust implies geochemical depletion of the underlying upper mantle, which serves to strengthen the lithosphere against thermal erosion by upper mantle convection. We infer that deep-source magnetic highs are an important indicator of strong lower crust and upper mantle. This stronger lithosphere forms buttresses that play an important role in the structural development of the northern Cordilleran fold-and-thrust belt. ?? 2007 The Geological Society of America.

Maternal age-specific risk of non-chromosomal anomalies

DEFF Research Database (Denmark)

Loane, M; Dolk, H; Morris, J K

2009-01-01

OBJECTIVES: To determine the excess risk of non-chromosomal congenital anomaly (NCA) among teenage mothers and older mothers. DESIGN AND SETTING: Population-based prevalence study using data from EUROCAT congenital anomaly registers in 23 regions of Europe in 15 countries, covering a total of 1.7...

Summer monsoon circulation and precipitation over the tropical Indian Ocean during ENSO in the NCEP climate forecast system

Science.gov (United States)

Chowdary, J. S.; Chaudhari, H. S.; Gnanaseelan, C.; Parekh, Anant; Suryachandra Rao, A.; Sreenivas, P.; Pokhrel, S.; Singh, P.

2014-04-01

This study investigates the El Niño Southern Oscillation (ENSO) teleconnections to tropical Indian Ocean (TIO) and their relationship with the Indian summer monsoon in the coupled general circulation model climate forecast system (CFS). The model shows good skill in simulating the impact of El Niño over the Indian Oceanic rim during its decay phase (the summer following peak phase of El Niño). Summer surface circulation patterns during the developing phase of El Niño are more influenced by local Sea Surface Temperature (SST) anomalies in the model unlike in observations. Eastern TIO cooling similar to that of Indian Ocean Dipole (IOD) is a dominant model feature in summer. This anomalous SST pattern therefore is attributed to the tendency of the model to simulate more frequent IOD events. On the other hand, in the model baroclinic response to the diabatic heating anomalies induced by the El Niño related warm SSTs is weak, resulting in reduced zonal extension of the Rossby wave response. This is mostly due to weak eastern Pacific summer time SST anomalies in the model during the developing phase of El Niño as compared to observations. Both eastern TIO cooling and weak SST warming in El Niño region combined together undermine the ENSO teleconnections to the TIO and south Asia regions. The model is able to capture the spatial patterns of SST, circulation and precipitation well during the decay phase of El Niño over the Indo-western Pacific including the typical spring asymmetric mode and summer basin-wide warming in TIO. The model simulated El Niño decay one or two seasons later, resulting long persistent warm SST and circulation anomalies mainly over the southwest TIO. In response to the late decay of El Niño, Ekman pumping shows two maxima over the southern TIO. In conjunction with this unrealistic Ekman pumping, westward propagating Rossby waves display two peaks, which play key role in the long-persistence of the TIO warming in the model (for more than a

Estimation of regional mass anomalies from Gravity Recovery and Climate Experiment (GRACE) over Himalayan region

Science.gov (United States)

Agrawal, R.; Singh, S. K.; Rajawat, A. S.; Ajai

2014-11-01

Time-variable gravity changes are caused by a combination of postglacial rebound, redistribution of water and snow/ice on land and as well as in the ocean. The Gravity Recovery and Climate Experiment (GRACE) satellite mission, launched in 2002, provides monthly average of the spherical harmonic co-efficient. These spherical harmonic co-efficient describe earth's gravity field with a resolution of few hundred kilometers. Time-variability of gravity field represents the change in mass over regional level with accuracies in cm in terms of Water Equivalent Height (WEH). The WEH reflects the changes in the integrated vertically store water including snow cover, surface water, ground water and soil moisture at regional scale. GRACE data are also sensitive towards interior strain variation, surface uplift and surface subsidence cover over a large area. GRACE data was extracted over the three major Indian River basins, Indus, Ganga and Brahmaputra, in the Himalayas which are perennial source of fresh water throughout the year in Northern Indian Plain. Time series analysis of the GRACE data was carried out from 2003-2012 over the study area. Trends and amplitudes of the regional mass anomalies in the region were estimated using level 3 GRACE data product with a spatial resolution at 10 by 10 grid provided by Center for Space Research (CSR), University of Texas at Austin. Indus basin has shown a subtle decreasing trend from 2003-2012 however it was observed to be statistically insignificant at 95 % confidence level. Ganga and Brahmaputra basins have shown a clear decreasing trend in WEH which was also observed to be statistically significant. The trend analysis over Ganga and Brahamputra basins have shown an average annual change of -1.28 cm and -1.06 cm in terms of WEH whereas Indus basin has shown a slight annual change of -0.07 cm. This analysis will be helpful to understand the loss of mass in terms of WEH over Indian Himalayas and will be crucial for hydrological and

Plasma position control in SST1 tokamak

Indian Academy of Sciences (India)

also placed inside the vessel, however the controller would ignore fast but insignificant changes in radius arising ... poloidal cross-sectional view of the SST1 plasma along with the stabilizers are shown in figure 1 and ... [1] model which has shown excellent agreement with control experiments in TCV tokamak and also with ...

Seasonal and inter-annual variability of surface circulation in the Bay of Bengal from TOPEX/Poseidon altimetry

Digital Repository Service at National Institute of Oceanography (India)

Somayajulu, Y.K.; Murty, V.S.N.; Sarma, Y.V.B.

- west monsoon period, (Fig. 5c) reflected the Fig.3. Variation of (a) Southern Oscillation Index (SOI) and (b) SST anomaly(Del. SST) in the Western Equatorial Pacific (WEP, NINO4, 51N–51S; 1601E–1501W) during the 5-year period (January1993–December 1997.... Inter-annual variation of SSH anomalyat selected locations: (a) off Sumatra (EEIO), (b) southern bay(SB), (c) eastern bay (EB), (d) northern bay(NB), (e) western bay(WB), and (f) central bay(CB). SST anomaly(Del. SST) is shown bydashed line in (a). Y...

Characteristics of uranium geological anomaly in Northern Guangdong province

International Nuclear Information System (INIS)

Wang Xinwu; Cheng Danping

2001-01-01

The geological anomaly characteristics of uranium deposit region in northern Guangdong are discussed on the aspects of uranium source, structure and thermal activity. Uranium deposits usually occur in the uranium-rich background field. Structure activity provides favourable places for the transportation and precipitation of uranium. Uranium deposits are formed in the central and edge of frequent thermal activity. The assembled entropy anomaly field is the synthetical display for above three anomaly. The biggest assembled entropy anomaly is the most favourable space field for forming uranium deposit

Maternal age-specific risk of non-chromosomal anomalies

NARCIS (Netherlands)

Loane, M.; Dolk, H.; Morris, Joan K.

To determine the excess risk of non-chromosomal congenital anomaly (NCA) among teenage mothers and older mothers. Population-based prevalence study using data from EUROCAT congenital anomaly registers in 23 regions of Europe in 15 countries, covering a total of 1.75 million births from 2000 to 2004.

Electronics and instrumentation for the SST-1 superconducting magnet system

International Nuclear Information System (INIS)

Khristi, Yohan; Pradhan, Subrata; Varmora, Pankaj; Banaudha, Moni; Praghi, Bhadresh R.; Prasad, Upendra

2015-01-01

Steady State Superconducting Tokamak-1 (SST-1) at Institute for Plasma Research (IPR), India is now in operation phase. The SST-1 magnet system consists of sixteen superconducting (SC), D-shaped Toroidal Field (TF) coils and nine superconducting Poloidal Field (PF) coils together with a pair of resistive PF coils, inside the vacuum vessel of SST-1. The magnets were cooled down to 4.5 K using either supercritical or two-phase helium, after which they were charged up to 10 kA of transport current. Precise quench detection system, cryogenic temperature, magnetic field, strain, displacement, flow and pressure measurements in the Superconducting (SC) magnet were mandatory. The Quench detection electronics required to protect the SC magnets from the magnet Quench therefore system must be reliable and prompt to detect the quench from the harsh tokamak environment and high magnetic field interference. A ∼200 channels of the quench detection system for the TF magnet are working satisfactorily with its design criteria. Over ∼150 channels Temperature measurement system was implemented for the several locations in the magnet and hydraulic circuits with required accuracy of 0.1K at bellow 30K cryogenic temperature. Whereas the field, strain and displacement measurements were carried out at few predefined locations on the magnet. More than 55 channels of Flow and pressure measurements are carried out to know the cooling condition and the mass flow of the liquid helium (LHe) coolant for the SC Magnet system. This report identifies the different in-house modular signal conditioning electronics and instrumentation systems, calibration at different levels and the outcomes for the SST-1 TF magnet system. (author)

SST, Aqua MODIS, NPP, 0.0125 degrees, Indonesia, Daytime

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch provides SST data from NASA's Aqua Spacecraft. Measurements are gathered by the Moderate Resolution Imaging Spectroradiometer (MODIS) carried aboard...

Demonstration of SST value as EBVs descriptor in the Mediterranean Sea

Science.gov (United States)

Valentini, E.; Filipponi, F.; Nguyen Xuan, A.; Taramelli, A.

2017-12-01

Sea Surface Temperature is an Essential Climate and Ocean Variable (ECV - EOV) able to capture critical scales in the seascape warming patterns and to highlight the exceeding of thresholds. This presentation addresses the changes of the SST in the last three decades over the Mediterranean Sea, a "Large Marine Ecosystem (LME)", in order to speculate the value of such powerful variable, as proxy for the assessment of ecosystem state in terms of ecosystem structures, functions and composition key descriptor. Time series of daily SST for the period 1982-2016, estimated from multi-sensor satellite data and provided by Copernicus Marine Environment Monitoring Service (CMEMS-EU) are used to perform different statistical analysis on common fish species. Results highlight the critical conditions, the general trends as well as the spatial and temporal patterns, in terms of thermal growth, vitality and stress influence on selected fish species. Results confirm a constant increasing trend in SST with an average rise of 1.4° C in the past thirty years. The variance associated to the average trend is not constant across the entire Mediterranean Sea opening the way to multiple scenarios for fish growth and vitality in the diverse sub-basins. A major effort is oriented in addressing the cross-scale ecological interactions to assess the feasibility of using SST as descriptor for Essential Biodiversity Variables, able to prioritize areas and to feed operational tools for planning and management in the Mediterranean LME.

NOAA High-Resolution Sea Surface Temperature (SST) Analysis Products

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This archive covers two high resolution sea surface temperature (SST) analysis products developed using an optimum interpolation (OI) technique. The analyses have a...

A Spatially Constrained Multi-autoencoder Approach for Multivariate Geochemical Anomaly Recognition

Science.gov (United States)

Lirong, C.; Qingfeng, G.; Renguang, Z.; Yihui, X.

2017-12-01

Separating and recognizing geochemical anomalies from the geochemical background is one of the key tasks in geochemical exploration. Many methods have been developed, such as calculating the mean ±2 standard deviation, and fractal/multifractal models. In recent years, deep autoencoder, a deep learning approach, have been used for multivariate geochemical anomaly recognition. While being able to deal with the non-normal distributions of geochemical concentrations and the non-linear relationships among them, this self-supervised learning method does not take into account the spatial heterogeneity of geochemical background and the uncertainty induced by the randomly initialized weights of neurons, leading to ineffective recognition of weak anomalies. In this paper, we introduce a spatially constrained multi-autoencoder (SCMA) approach for multivariate geochemical anomaly recognition, which includes two steps: spatial partitioning and anomaly score computation. The first step divides the study area into multiple sub-regions to segregate the geochemical background, by grouping the geochemical samples through K-means clustering, spatial filtering, and spatial constraining rules. In the second step, for each sub-region, a group of autoencoder neural networks are constructed with an identical structure but different initial weights on neurons. Each autoencoder is trained using the geochemical samples within the corresponding sub-region to learn the sub-regional geochemical background. The best autoencoder of a group is chosen as the final model for the corresponding sub-region. The anomaly score at each location can then be calculated as the euclidean distance between the observed concentrations and reconstructed concentrations of geochemical elements.The experiments using the geochemical data and Fe deposits in the southwestern Fujian province of China showed that our SCMA approach greatly improved the recognition of weak anomalies, achieving the AUC of 0.89, compared

Comparing soil moisture anomalies from multiple independent sources over different regions across the globe

Directory of Open Access Journals (Sweden)

C. Cammalleri

2017-12-01

Full Text Available Agricultural drought events can affect large regions across the world, implying the need for a suitable global tool for an accurate monitoring of this phenomenon. Soil moisture anomalies are considered a good metric to capture the occurrence of agricultural drought events, and they have become an important component of several operational drought monitoring systems. In the framework of the JRC Global Drought Observatory (GDO, http://edo.jrc.ec.europa.eu/gdo/, the suitability of three datasets as possible representations of root zone soil moisture anomalies has been evaluated: (1 the soil moisture from the Lisflood distributed hydrological model (namely LIS, (2 the remotely sensed Land Surface Temperature data from the MODIS satellite (namely LST, and (3 the ESA Climate Change Initiative combined passive/active microwave skin soil moisture dataset (namely CCI. Due to the independency of these three datasets, the triple collocation (TC technique has been applied, aiming at quantifying the likely error associated with each dataset in comparison to the unknown true status of the system. TC analysis was performed on five macro-regions (namely North America, Europe, India, southern Africa and Australia detected as suitable for the experiment, providing insight into the mutual relationship between these datasets as well as an assessment of the accuracy of each method. Even if no definitive statement on the spatial distribution of errors can be provided, a clear outcome of the TC analysis is the good performance of the remote sensing datasets, especially CCI, over dry regions such as Australia and southern Africa, whereas the outputs of LIS seem to be more reliable over areas that are well monitored through meteorological ground station networks, such as North America and Europe. In a global drought monitoring system, the results of the error analysis are used to design a weighted-average ensemble system that exploits the advantages of each dataset.

Euro-African MAGSAT anomaly-tectonic observations

Science.gov (United States)

Hinze, W. J.; Olivier, R.; Vonfrese, R. R. B.

1985-01-01

Preliminary satellite (MAGSAT) scalar magnetic anomaly data are compiled and differentially reduced to radial polarization by equivalent point source inversion for comparison with tectonic data of Africa, Europe and adjacent marine areas. A number of associations are evident to constrain analyses of the tectonic features and history of the region. The Precambrian shields of Africa and Europe exhibit varied magnetic signatures. All shields are not magnetic highs and, in fact, the Baltic shield is a marked minimum. The reduced-to-the-pole magnetic map shows a marked tendency for northeasterly striking anomalies in the eastern Atlantic and adjacent Africa, which is coincident to the track of several hot spots for the past 100 million years. However, there is little consistency in the sign of the magnetic anomalies and the track of the hot spots. Comparison of the radially polarized anomalies of Africa and Europe with other reduced-to-the-pole magnetic satellite anomaly maps of the Western Hemisphere support the reconstruction of the continents prior to the origin of the present-day Atlantic Ocean in the Mesozoic Era.

Upgradation in SCADA and PLC of existing LN_2 control system for SST-1

International Nuclear Information System (INIS)

Panchal, Pradip; Mahesuria, Gaurang; Panchal, Rohit; Patel, Rakesh; Sonara, Dashrath; Pitroda, Dipen; Nimavat, Hiren; Tanna, Vipul; Pradhan, Subrata

2016-01-01

Highlights: • The control system of LN_2 Management System of SST-1 is designed on PLC and SCADA. • The implementation and results of up-gradation in PLC and SCADA are reported. • The up-gradation in PLC and SCADA has improved the reliability & availability of SST-1 LN_2 system. - Abstract: Helium Refrigerator/Liquefier system of Steady State Superconducting Tokamak (SST-1) incorporates Liquid Nitrogen (LN_2) pre-cooling system. LN_2 is used for 80 K thermal shields of SST-1, current feeder system and integrated flow distribution and control system. The LN_2 management system is distributed system and requires automatic control. Initially LN_2 control system had Citect based Supervisory Control and Data Acquisition (SCADA) and Koyo make Programmable Logic Controller (PLC). With the passage of time and due to unavailability of their hardware, it is being obsoleted. So, the requirements of new PLC and SCADA systems have been envisaged to make uninterruptable operation of SST-1 cryogenic system. Therefore, Wonderware SCADA and Schneider Electric make PLC is programmed to replace Citect SCADA and Koyo PLC. New control features have been added in upgraded control system for better management of LN_2 system. This upgradation of SCADA and PLC is completed, tested successfully and in operation. Operational performance highlights of the new upgraded system are presented in this paper.

Simulation of Tropical Rainfall Variability

Science.gov (United States)

Bader, J.; Latif, M.

2002-12-01

The impact of sea surface temperature (SST) - especially the role of the tropical Atlantic meridional SST gradient and the El Nino-Southern Oscillation - on precipitation is investigated with the atmospheric general circulation model ECHAM4/T42. Ensemble experiments - driven with observed SST - show that Atlantic SST has a significant influence on precipitation over West Africa and northeast Brazil. SST sensitivity experiments were performed in which the climatological SST was enhanced or decreased by one Kelvin in certain ocean areas. Changing SST in the eastern tropical Atlantic caused only significant changes along the Guinea Coast, with a positive anomaly (SSTA) increasing rainfall and a negative SSTA reducing it. The response was nearly linear. Changing SST in other ocean areas caused significant changes over West Africa, especially in the Sahel area. The response is found to be non linear, with only negative SSTA leading to significant reduction in Sahel rainfall. Also, the impact of the SSTAs from the different ocean regions was not additive with respect to the rainfall. The influence of SST on precipitation over northeast Brazil (Nordeste) was also investigated. Three experiments were performed in which the climatological SST was enhanced/decreased or decreased/enhanced by one Kelvin in the North/South Atlantic and increased by two Kelvin in the Nino3 ocean area. All experiments caused significant changes over Nordeste, with an enhanced/reduced SST gradient in the Atlantic increasing/reducing rainfall. The response was nearly linear. The main effect of the Atlantic SST gradient was a shift of the ITCZ, caused by trade wind changes. The ''El Nino'' event generates a significant reduction in Nordeste rainfall. A significant positive SLP anomaly occurs in northeast Brazil which may be associated with the descending branch of the Walker circulation. Also a significant positive SLP over the Atlantic from 30S to 10N north occurs. This results in a reduced SLP

Ionospheric Anomaly before Kyushu|Japan Earthquake

Directory of Open Access Journals (Sweden)

YANG Li

2017-05-01

Full Text Available GIM data released by IGS is used in the article and a new method of combining the Sliding Time Window Method and the Ionospheric TEC correlation analysis method of adjacent grid points is proposed to study the relationship between pre-earthquake ionospheric anomalies and earthquake. By analyzing the abnormal change of TEC in the 5 grid points around the seismic region, the abnormal change of ionospheric TEC is found before the earthquake and the correlation between the TEC sequences of lattice points is significantly affected by earthquake. Based on the analysis of the spatial distribution of TEC anomaly, anomalies of 6 h, 12 h and 6 h were found near the epicenter three days before the earthquake. Finally, ionospheric tomographic technology is used to do tomographic inversion on electron density. And the distribution of the electron density in the ionospheric anomaly is further analyzed.

Mechanisms of the intensification of the upwelling-favorable winds during El Niño 1997-1998 in the Peruvian upwelling system

Science.gov (United States)

Chamorro, Adolfo; Echevin, Vincent; Colas, François; Oerder, Vera; Tam, Jorge; Quispe-Ccalluari, Carlos

2018-01-01

The physical processes driving the wind intensification in a coastal band of 100 km off Peru during the intense 1997-1998 El Niño (EN) event were studied using a regional atmospheric model. A simulation performed for the period 1994-2000 reproduced the coastal wind response to local sea surface temperature (SST) forcing and large scale atmospheric conditions. The model, evaluated with satellite data, represented well the intensity, seasonal and interannual variability of alongshore (i.e. NW-SE) winds. An alongshore momentum budget showed that the pressure gradient was the dominant force driving the surface wind acceleration. The pressure gradient tended to accelerate the coastal wind, while turbulent vertical mixing decelerated it. A quasi-linear relation between surface wind and pressure gradient anomalies was found. Alongshore pressure gradient anomalies were caused by a greater increase in near-surface air temperature off the northern coast than off the southern coast, associated with the inhomogeneous SST warming. Vertical profiles of wind, mixing coefficient, and momentum trends showed that the surface wind intensification was not caused by the increase of turbulence in the planetary boundary layer. Moreover, the temperature inversion in the vertical mitigated the development of pressure gradient due to air convection during part of the event. Sensitivity experiments allowed to isolate the respective impacts of the local SST forcing and large scale condition on the coastal wind intensification. It was primarily driven by the local SST forcing whereas large scale variability associated with the South Pacific Anticyclone modulated its effects. Examination of other EN events using reanalysis data confirmed that intensifications of alongshore wind off Peru were associated with SST alongshore gradient anomalies, as during the 1997-1998 event.

A Time Series of Mean Global Sea Surface Temperature from the Along-Track Scanning Radiometers

Science.gov (United States)

Veal, Karen L.; Corlett, Gary; Remedios, John; Llewellyn-Jones, David

2010-12-01

A climate data set requires a long time series of consistently processed data with suitably long periods of overlap of different instruments which allows characterization of any inter-instrument biases. The data obtained from ESA's three Along-Track Scanning Radiometers (ATSRs) together comprise an 18 year record of SST with overlap periods of at least 6 months. The data from all three ATSRs has been consistently processed. These factors together with the stability of the instruments and the precision of the derived SST makes this data set eminently suitable for the construction of a time series of SST that complies with many of the GCOS requirements for a climate data set. A time series of global and regional average SST anomalies has been constructed from the ATSR version 2 data set. An analysis of the overlap periods of successive instruments was used to remove intra-series biases and align the series to a common reference. An ATSR climatology has been developed and has been used to calculate the SST anomalies. The ATSR-1 time series and the AATSR time series have been aligned to ATSR-2. The largest adjustment is ~0.2 K between ATSR-2 and AATSR which is suspected to be due to a shift of the 12 μm filter function for AATSR. An uncertainty of 0.06 K is assigned to the relative anomaly record that is derived from the dual three-channel night-time data. A relative uncertainty of 0.07 K is assigned to the dual night-time two-channel record, except in the ATSR-1 period (1994-1996) where it is larger.

Monthly SST images of Stellwagen Bank National Marine Sanctuary

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Average monthy Sea Surfact Temperature http://podaac.jpl.nasa.gov/ Naming Convention: XXXX_YYYYMM_SST.tif XXXX=location (Stell) YYYY=year MM=month Example filename:...

Prior history of Mistral and Tramontane winds modulates heavy precipitation events in southern France

Directory of Open Access Journals (Sweden)

Ségolène Berthou

2014-11-01

Full Text Available Heavy precipitation events (HPEs are frequent in southern France in autumn. An HPE results from landward transport of low-level moisture from the Western Mediterranean: large potential instability is then released by local convergence and/or orography. In the upstream zone, the sea surface temperature (SST undergoes significant variations at the submonthly time scale primarily driven by episodic highly energetic events of relatively cold outflows from the neighbouring mountain ranges (the Mistral and Tramontane winds. Here, we study the HPE of 22–23 September 1994 which is preceded by a strong SST cooling due to the Mistral and Tramontane winds. This case confirms that the location of the precipitation is modulated by the SST in the upstream zone. In fact, changes in latent and sensible heat fluxes due to SST changes induce pressure and stratification changes which affect the low-level dynamics. Using three companion regional climate simulations running from 1989 to 2009, this article statistically shows that anomalies in the HPEs significantly correlate with the SST anomalies in the Western Mediterranean, and hence with the prior history of Mistral and Tramontane winds. In such cases, the role of the ocean as an integrator of the effect of past wind events over one or several weeks does indeed have an impact on HPEs in southern France.

Extremes in East African hydroclimate and links to Indo-Pacific variability on interannual to decadal timescales

Science.gov (United States)

Ummenhofer, Caroline C.; Kulüke, Marco; Tierney, Jessica E.

2018-04-01

East African hydroclimate exhibits considerable variability across a range of timescales, with implications for its population that depends on the region's two rainy seasons. Recent work demonstrated that current state-of-the-art climate models consistently underestimate the long rains in boreal spring over the Horn of Africa while overestimating the short rains in autumn. This inability to represent the seasonal cycle makes it problematic for climate models to project changes in East African precipitation. Here we consider whether this bias also has implications for understanding interannual and decadal variability in the East African long and short rains. Using a consistent framework with an unforced multi-century global coupled climate model simulation, the role of Indo-Pacific variability for East African rainfall is compared across timescales and related to observations. The dominant driver of East African rainfall anomalies critically depends on the timescale under consideration: Interannual variations in East African hydroclimate coincide with significant sea surface temperature (SST) anomalies across the Indo-Pacific, including those associated with the El Niño-Southern Oscillation (ENSO) in the eastern Pacific, and are linked to changes in the Walker circulation, regional winds and vertical velocities over East Africa. Prolonged drought/pluvial periods in contrast exhibit anomalous SST predominantly in the Indian Ocean and Indo-Pacific warm pool (IPWP) region, while eastern Pacific anomalies are insignificant. We assessed dominant frequencies in Indo-Pacific SST and found the eastern equatorial Pacific dominated by higher-frequency variability in the ENSO band, while the tropical Indian Ocean and IPWP exhibit lower-frequency variability beyond 10 years. This is consistent with the different contribution to regional precipitation anomalies for the eastern Pacific versus Indian Ocean and IPWP on interannual and decadal timescales, respectively. In the model

Stratospheric role in interdecadal changes of El Niño impacts over Europe

Science.gov (United States)

Ayarzagüena, B.; López-Parages, J.; Iza, M.; Calvo, N.; Rodríguez-Fonseca, B.

2018-04-01

The European precipitation response to El Niño (EN) has been found to present interdecadal changes, with alternated periods of important or negligible EN impact in late winter. These periods are associated with opposite phases of multi-decadal sea surface temperature (SST) variability, which modifies the tropospheric background and EN teleconnections. In addition, other studies have shown how SST anomalies in the equatorial Pacific, and in particular, the location of the largest anomalous SST, modulate the stratospheric response to EN. Nevertheless, the role of the stratosphere on the stationarity of EN response has not been investigated in detail so far. Using reanalysis data, we present a comprehensive study of EN teleconnections to Europe including the role of the ocean background and the stratosphere in the stationarity of the signal. The results reveal multidecadal variability in the location of EN-related SST anomalies that determines different teleconnections. In periods with relevant precipitation signal over Europe, the EN SST pattern resembles Eastern Pacific EN and the stratospheric pathway plays a key role in transmitting the signal to Europe in February, together with two tropospheric wavetrains that transmit the signal in February and April. Conversely, the stratospheric pathway is not detected in periods with a weak EN impact on European precipitation, corresponding to EN-related SST anomalies primarily located over the central Pacific. SST mean state and its associated atmospheric background control the location of EN-related SST anomalies in different periods and modulate the establishment of the aforementioned stratospheric pathway of EN teleconnection to Europe too.

Data-Model Comparison of Pliocene Sea Surface Temperature

Science.gov (United States)

Dowsett, H. J.; Foley, K.; Robinson, M. M.; Bloemers, J. T.

2013-12-01

The mid-Piacenzian (late Pliocene) climate represents the most geologically recent interval of long-term average warmth and shares similarities with the climate projected for the end of the 21st century. As such, its fossil and sedimentary record represents a natural experiment from which we can gain insight into potential climate change impacts, enabling more informed policy decisions for mitigation and adaptation. We present the first systematic comparison of Pliocene sea surface temperatures (SST) between an ensemble of eight climate model simulations produced as part of PlioMIP (Pliocene Model Intercomparison Project) and the PRISM (Pliocene Research, Interpretation and Synoptic Mapping) Project mean annual SST field. Our results highlight key regional (mid- to high latitude North Atlantic and tropics) and dynamic (upwelling) situations where there is discord between reconstructed SST and the PlioMIP simulations. These differences can lead to improved strategies for both experimental design and temporal refinement of the palaeoenvironmental reconstruction. Scatter plot of multi-model-mean anomalies (squares) and PRISM3 data anomalies (large blue circles) by latitude. Vertical bars on data anomalies represent the variability of warm climate phase within the time-slab at each locality. Small colored circles represent individual model anomalies and show the spread of model estimates about the multi-model-mean. While not directly comparable in terms of the development of the means nor the meaning of variability, this plot provides a first order comparison of the anomalies. Encircled areas are a, PRISM low latitude sites outside of upwelling areas; b, North Atlantic coastal sequences and Mediterranean sites; c, large anomaly PRISM sites from the northern hemisphere. Numbers identify Ocean Drilling Program sites.

Satellite magnetic anomalies of the Antarctic crust

Directory of Open Access Journals (Sweden)

D. E. Alsdorf

2000-06-01

Full Text Available Spatially and temporally static crustal magnetic anomalies are contaminated by static core field effects above spherical harmonic degree 12 and dynamic, large-amplitude external fields. To extract crustal magnetic anomalies from the measurements of NASA's Magsat mission, we separate crustal signals from both core and external field effects. In particular, we define Magsat anomalies relative to the degree 11 field and use spectral correlation theory to reduce them for external field effects. We obtain a model of Antarctic crustal thickness by comparing the region's terrain gravity effects to free-air gravity anomalies derived from the Earth Gravity Model 1996 (EGM96. To separate core and crustal magnetic effects, we obtain the pseudo-magnetic effect of the crustal thickness variations from their gravity effect via Poisson's theorem for correlative potentials. We compare the pseudo-magnetic effect of the crustal thickness variations to field differences between degrees 11 and 13 by spectral correlation analysis. We thus identify and remove possible residual core field effects in the Magsat anomalies relative to the degree 11 core field. The resultant anomalies reflect possible Antarctic contrasts due both to crustal thickness and intracrustal variations of magnetization. In addition, they provide important constraints on the geologic interpretation of aeromagnetic survey data, such as are available for the Weddell Province. These crustal anomalies also may be used to correct for long wavelength errors in regional compilations of near-surface magnetic survey data. However, the validity of these applications is limited by the poor quality of the Antarctic Magsat data that were obtained during austral Summer and Fall when south polar external field activity was maximum. Hence an important test and supplement for the Antarctic crustal Magsat anomaly map will be provided by the data from the recently launched Ørsted mission, which will yield coverage

Criticality in the fabrication of ion extraction system for SST-1 neutral beam injector

International Nuclear Information System (INIS)

Jana, M.R.; Mattoo, S.K.

2008-01-01

For the heating of plasma in steady-state superconducting tokamak (SST-1) (Y.C. Saxena, SST-1 Team, Present status of the SST-1 project, Nucl. Fusion 40 (2000) 1069-1082; D. Bora, SST-1 Team, Test results on systems developed for the SST-1 tokamak, Nucl. Fusion 43 (2003) 1748-1758), a neutral beam injector is provided to raise the ion temperature to ∼1 keV. This injector has a capability of injecting hydrogen beam with the power of 0.5 MW at 30 keV. For the upgrade of SST-1, power of 1.7 MW at 55 KeV is required. Further, beam power is to be provided for a pulse length of 1000S. We have designed a neutral beam injector (S.K. Mattoo, A.K. Chakraborty, U.K. Baruah, P.K. Jayakumar, M. Bandyopadhyay, N. Bisai, Ch. Chakrapani, M.R. Jana, R. Onali, V. Prahlad, P.J. Patel, G.B. Patel, B. Prajapati, N.V.M. Rao, S. Rambabu, C. Rotti, S.K. Sharma, S. Shah, V. Sharma, M.J. Singh, Engineering design of the steady-state neutral beam injector for SST-1, Fusion Eng. Des. 56 (2001) 685-691; A.K. Chakraborty, N. Bisai, M.R. Jana, P.K. Jayakumar, U.K. Baruah, P.J. Patel, K. Rajasekar, S.K. Mattoo, Neutral beam injector for steady-state superconducting tokamak, Fusion Technol. (1996) 657-660; P.K. Jayakumar, M.R. Jana, N. Bisai, M. Bajpai, N.P. Singh, U.K. Baruah, A.K. Chakraborty, M. Bandyopadhyay, C. Chrakrapani, D. Patel, G.B. Patel, P. Patel, V. Prahlad, N.V.M. Rao, C. Rotti, V. Sreedhar, S.K. Mattoo, Engineering issues of a 1000S neutral beam ion source, Fusion Technol. 1 (1998) 419-422) satisfying the requirements for both SST-1 and its upgrade. Since intense power is to be transported to SST-1 situated at a distance of several meters from the ion source, the optical quality of the beam becomes a primary concern. This in turn, is determined by the uniformity of the ion source plasma and the extractor geometry. To obtain the desired optical quality of the beam, stringent tolerances are to be met during the fabrication of ion extractor system. SST-1 neutral beam injector is

Operational and troubleshooting experiences in the SST-1 cryogenic system

Science.gov (United States)

Mahesuria, G.; Panchal, P.; Panchal, R.; Patel, R.; Sonara, D.; Gupta, N. C.; Srikanth, G. L. N.; Christian, D.; Garg, A.; Bairagi, N.; Patel, K.; Shah, P.; Nimavat, H.; Sharma, R.; Patel, J. C.; Tank, J.; Tanna, V. L.; Pradhan, S.

2014-01-01

Recently, the cooldown and current charging campaign have been carried out towards the demonstration of the first successful plasma discharge in the steady state superconducting Tokomak (SST-1). The SST-1 machine consists of cable-in-conduit wound superconducting toroidal as well as poloidal coils, cooled using 1.3 kW at 4.5 K helium refrigerator -cum- liquefier (HRL) system. The cryo system provides the two-phase helium at 0.13 MPa at 4.5 K as well as forced-flow pressurized helium at 0.4 MPa and in addition to 7 g-s-1 liquefaction capacity required for the current leads and other cold mass at 4.5 K. The entire integrated cold masses having different thermo hydraulic resistances cooled with the SST-1 HRL in optimised process parameters. In order to maintain different levels of temperatures and to facilitate smooth and reliable cooldown, warm-up, normal operations as well as to handle abnormal events such as, quench or utilities failures etc., exergy efficient process are adopted for the helium refrigerator-cum-liquefier (HRL) with an installed equivalent capacity of 1.3 kW at 4.5 K. Using the HRL, the cold mass of about 40 tons is being routinely cooled down from ambient temperature to 4.5 K with an average cooldown rate of 0.75 - 1 K-h-1. Long-term cryogenic stable conditions were obtained within 15 days in the superconducting coils and their connecting feeders. Afterwards, all of the cold mass is warmed-up in a controlled manner to ambient temperature. In this paper, we report the recent operational results of the cryogenic system during the first plasma discharge in SST-1 as well as the troubleshooting experiences of the cryogenic plant related hardware.

Estimasi Kedalaman Dengan Spektral 1Dimensin Terhadap Data Anomali Bouguer Lengkap

OpenAIRE

Maria, Maria

2003-01-01

Telah dilakukan interpretasi terhadap data anomali gravitasi Bouguer lengkap dari data pengukuran di daerah gunng Merapi dan gunung Merbabu, untuk mengatahui kedalaman struktur lokal dan regional. Data anomali Bouguer lengkap di proyeksikan ke bidang datar pada ketinggian 4 km di atas sferoida referensi. perhitungan kedalaman struktur lokal dan regional diperolah berdasarkan analisis spektral 1-Dimensi.

Influence of Atlantic on the warming and reduction of sea ice in the Arctic

Directory of Open Access Journals (Sweden)

G. V. Alekseev

2017-01-01

Full Text Available Influence of anomalies of the sea surface temperature (SST in low latitudes of the North Atlantic on the sea ice cover and the near-surface air temperature in the marine Arctic is discussed in the article. Data on the SST in the Atlantic Ocean from the HadISST dataset, climatic series of the water temperature at the section along the Kola meridian together with mean monthly data on the sea ice extent and the air surface temperature in the Maritime Arctic and the Northern hemisphere were analyzed. Multivariate cross-correlation analysis was applied to determine the maximum correlation coefficients between the SST anomalies, climate characteristics and their corresponding delays within time limits of 33 to 38 months. Existence of intimate link had been found between changes of the Atlantic SST in low latitudes and the sea ice extent in the Arctic with correlation coefficients up to 0.90 and delays up to 3 years. A mechanism of formation of the remote influence of low-latitude SST anomalies on the sea ice anomalies in the Arctic Ocean is proposed. The interpretation of this mechanism includes into consideration the interaction between atmospheric and oceanic circulation modes.

Comparison of two Centennial-scale Sea Surface Temperature Datasets in the Regional Climate Change Studies of the China Seas

Science.gov (United States)

Qingyuan, Wang; Yanan, Wang; Yiwei, Liu

2017-08-01

Two widely used sea surface temperature (SST) datasets are compared in this article. We examine characteristics in the climate variability of SST in the China Seas.Two series yielded almost the same warming trend for 1890-2013 (0.7-0.8°C/100 years). However, HadISST1 series shows much stronger warming trends during 1961-2013 and 1981-2013 than that of COBE SST2 series. The disagreement between data sets was marked after 1981. For the hiatus period 1998-2013, the cooling trends of HadISST1 series is much lower than that of COBE SST2. These differences between the two datasets are possibly caused by the different observations which are incorporated to fill with data-sparse regions since 1982. Those findings illustrate that there are some uncertainties in the estimate of SST warming patterns in certain regions. The results also indicate that the temporal and spatial deficiency of observed data is still the biggest handicap for analyzing multi-scale SST characteristics in regional area.

Global magnetic anomaly and aurora of Neptune

International Nuclear Information System (INIS)

Cheng, A.F.

1990-01-01

The large offset and tilt of Neptune's dipole magnetic field combine to create a global magnetic anomaly, analogous to but much more important than Earth's South Atlantic Anomaly. Energetic particle precipitation loss within the Neptune anomaly creates atmospheric drift shadows within which particle fluxes are greatly reduced. The energetic particle dropout observed by Voyager near closest approach occurred near the predicted times when Voyager passed within the atmospheric drift shadow. Extremely soft, structured bursts of ions and electrons within the drift shadow may result from plasma wave-induced pitch angle scattering of trapped particles confined near the magnetic equator. The dropout does not necessarily imply that Voyager passed through an Earth-like discrete auroral zone, as earlier reported. The ion and electron fluxes observed within the dropout period correspond to particles that must precipitate to Neptune's atmosphere within the anomaly region. This anomaly precipitation can account for a major portion of the ultraviolet emissions previously identified as Neptune aurora

The 30-60-day Intraseasonal Variability of Sea Surface Temperature in the South China Sea dur1ing May-September

Science.gov (United States)

Mao, Jiangyu; Wang, Ming

2018-05-01

This study investigates the structure and propagation of intraseasonal sea surface temperature (SST) variability in the South China Sea (SCS) on the 30-60-day timescale during boreal summer (May-September). TRMM-based SST, GODAS oceanic reanalysis and ERA-Interim atmospheric reanalysis datasets from 1998 to 2013 are used to examine quantitatively the atmospheric thermodynamic and oceanic dynamic mechanisms responsible for its formation. Power spectra show that the 30-60-day SST variability is predominant, accounting for 60% of the variance of the 10-90-day variability over most of the SCS. Composite analyses demonstrate that the 30-60-day SST variability is characterized by the alternate occurrence of basin-wide positive and negative SST anomalies in the SCS, with positive (negative) SST anomalies accompanied by anomalous northeasterlies (southwesterlies). The transition and expansion of SST anomalies are driven by the monsoonal trough-ridge seesaw pattern that migrates northward from the equator to the northern SCS. Quantitative diagnosis of the composite mixed-layer heat budgets shows that, within a strong 30-60-day cycle, the atmospheric thermal forcing is indeed a dominant factor, with the mixed-layer net heat flux (MNHF) contributing around 60% of the total SST tendency, while vertical entrainment contributes more than 30%. However, the entrainment-induced SST tendency is sometimes as large as the MNHF-induced component, implying that ocean processes are sometimes as important as surface fluxes in generating the 30-60-day SST variability in the SCS.

Observations of Local Positive Low Cloud Feedback Patterns and Their Role in Internal Variability and Climate Sensitivity

Science.gov (United States)

Yuan, Tianle; Oreopoulos, Lazaros; Platnick, Steven E.; Meyer, Kerry

2018-05-01

Modeling studies have shown that cloud feedbacks are sensitive to the spatial pattern of sea surface temperature (SST) anomalies, while cloud feedbacks themselves strongly influence the magnitude of SST anomalies. Observational counterparts to such patterned interactions are still needed. Here we show that distinct large-scale patterns of SST and low-cloud cover (LCC) emerge naturally from objective analyses of observations and demonstrate their close coupling in a positive local SST-LCC feedback loop that may be important for both internal variability and climate change. The two patterns that explain the maximum amount of covariance between SST and LCC correspond to the Interdecadal Pacific Oscillation and the Atlantic Multidecadal Oscillation, leading modes of multidecadal internal variability. Spatial patterns and time series of SST and LCC anomalies associated with both modes point to a strong positive local SST-LCC feedback. In many current climate models, our analyses suggest that SST-LCC feedback strength is too weak compared to observations. Modeled local SST-LCC feedback strength affects simulated internal variability so that stronger feedback produces more intense and more realistic patterns of internal variability. To the extent that the physics of the local positive SST-LCC feedback inferred from observed climate variability applies to future greenhouse warming, we anticipate significant amount of delayed warming because of SST-LCC feedback when anthropogenic SST warming eventually overwhelm the effects of internal variability that may mute anthropogenic warming over parts of the ocean. We postulate that many climate models may be underestimating both future warming and the magnitude of modeled internal variability because of their weak SST-LCC feedback.

Daily MUR SST, Interim near-real-time (nrt) product

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A daily, global Sea Surface Temperature (SST) data set is produced at 1-km (MUR, or Multi-scale ultra-high resolution Temperature) by the JPL sciengists Drs. Mike...

GHRSST Level 2P European Medspiration SEVIRI SST:1

Data.gov (United States)

National Aeronautics and Space Administration — SST calculated from the IR channels of MSG at full resolution on a hourly basis. Remapping is made by space averaging, the production of the 3-hourly data is made by...

Type II first branchial cleft anomaly.

Science.gov (United States)

Al-Mahdi, Akmam H; Al-Khurri, Luay E; Atto, Ghada Z; Dhaher, Ameer

2013-01-01

First branchial cleft anomaly is a rare disease of the head and neck. It accounts for less than 8% of all branchial abnormalities. It is classified into type I, which is thought to arise from the duplication of the membranous external ear canal and are composed of ectoderm only, and type II that have ectoderm and mesoderm. Because of its rarity, first branchial cleft anomaly is often misdiagnosed and results in inappropriate management. A 9-year-old girl presented to us with fistula in the submandibular region and discharge in the external ear. Under general anesthesia, complete surgical excision of the fistula tract was done through step-ladder approach, and the histopathologic examination confirmed the diagnosis of type II first branchial cleft anomaly.

Development and Integration of a Data Acquisition System for SST-1 Phase-1 Plasma Diagnostics

International Nuclear Information System (INIS)

Srivastava, Amit K; Sharma, Manika; Mansuri, Imran; Sharma, Atish; Raval, Tushar; Pradhan, Subrata

2012-01-01

Long pulse (of the order of 1000 s or more) SST-1 tokamak experiments demand a data acquisition system that is capable of acquiring data from various diagnostics channels without losing useful data (and hence physics information) while avoiding unnecessary generation of a large volume data. SST-1 Phase-1 tokamak operation has been envisaged with data acquisition of several essential diagnostics channels. These channels demand data acquisition at a sampling rate ranging from 1 kilo samples per second (KSPS) to 1 mega samples per second (MSPS). Considering the technical characteristics and requirements of the diagnostics, a data acquisition system based on PXI and CAMAC has been developed for SST-1 plasma diagnostics. Both these data acquisition systems are scalable. Present data acquisition needs involving slow plasma diagnostics are catered by the PXI based data acquisition system. On the other hand, CAMAC data acquisition hardware meets all requirements of the SST-1 Phase-1 fast plasma diagnostics channels. A graphical user interface for both data acquisition systems (PXI and CAMAC) has been developed using LabVIEW application development software. The collected data on the local hard disk are directly streaming to the central server through a dedicated network for post-shot data analysis. This paper describes the development and integration of the data acquisition system for SST-1 Phase-1 plasma diagnostics. The integrated testing of the developed data acquisition system has been performed using SST-1 central control and diagnostics signal conditioning units. In the absence of plasma shots, the integrated testing of the data acquisition system for the initial diagnostics of SST-1 Phase-1 operation has been performed with simulated physical signals. The primary engineering objective of this integrated testing is to validate the performance of the developed data acquisition system under simulated conditions close to that of actual tokamak operation. The data

Thermal structural analysis of SST-1 vacuum vessel and cryostat assembly using ANSYS

International Nuclear Information System (INIS)

Santra, Prosenjit; Bedakihale, Vijay; Ranganath, Tata

2009-01-01

Steady state super-conducting tokamak-1 (SST-1) is a medium sized tokamak, which has been designed to produce a 'D' shaped double null divertor plasma and operate in quasi steady state (1000 s). SST-1 vacuum system comprises of plasma chamber (vacuum vessel, interconnecting rings, baking and cooling channels), and cryostat all made of SS 304L material designed to meet ultra high vacuum requirements for plasma generation and confinement. Prior to plasma shot and operation the vessel assembly is baked to 250/150 deg. C from room temperature and discharge cleaned to remove impurities/trapped gases from wall surfaces. Due to baking the non-uniform temperature pattern on the vessel assembly coupled with atmospheric pressure loading and self-weight give rise to high thermal-structural stresses, which needs to be analyzed in detail. In addition the vessel assembly being a thin shell vessel structure needs to be checked for critical buckling load caused by atmospheric and baking thermal loads. Considering symmetry of SST-1, 1/16th of the geometry is modeled for finite element (FE) analysis using ANSYS for different loading scenarios, e.g. self-weight, pressure loading considering normal operating conditions, and off-normal loads coupled with baking of vacuum vessel from room temperature 250 deg. C to 150 deg. C, buckling and modal analysis for future dynamic analysis. The paper will discuss details about SST-1 vacuum system/cryostat, solid and FE model of SST-1, different loading scenarios, material details and the stress codes used. We will also present the thermal structural results of FE analysis using ANSYS for various load cases being investigated and our observations under different loading conditions.

Cryogenic system of steady state superconducting Tokamak SST-1: Operational experience and controls

International Nuclear Information System (INIS)

Sarkar, B.; Tank, Jignesh; Panchal, Pradip; Sahu, A.K.; Bhattacharya, Ritendra; Phadke, Gaurang; Gupta, N.C.; Gupta, Girish; Shah, Nitin; Shukla, Pawan; Singh, Manoj; Sonara, Dasarath; Sharma, Rajiv; Saradha, S.; Patel, J.C.; Saxena, Y.C.

2006-01-01

The cryogenic system of SST-1 consists of the helium cryogenic system and the nitrogen cryogenic system. The main components of the helium cryogenic system are (a) 1.3 kW helium refrigerator/liquefier (HRL) and (b) warm gas management system (WGM), where as, the nitrogen cryogenic system called as liquid nitrogen (LN 2 ) management system consists of storage tanks and a distribution system. The helium flow distribution and control to different sub-systems is achieved by the integrated flow distribution and control (IFDC) system. The HRL has been commissioned and operated for performing a single toroidal field coil test as well as for the first commissioning of SST-1 superconducting-magnets up to 68 K. Analysis of the results shows that the compressor and turbine parameters of the HRL, namely, the speed and pressure are very stable during operation of the HRL, confirming to the reliability in control of thermo-dynamic parameters of the system. The thermal shield of the SST-1 cryostat consists of ten different types of panels, which have been cooled down to the minimum temperature of 80 K and maintained during the first commissioning of SST-1. The operation and controls of the LN2 management system have been found to be as per the design consideration

ELLERMAN BOMBS AT HIGH RESOLUTION. III. SIMULTANEOUS OBSERVATIONS WITH IRIS AND SST

Energy Technology Data Exchange (ETDEWEB)

Vissers, G. J. M.; Voort, L. H. M. Rouppe van der; Rutten, R. J.; Carlsson, M.; Pontieu, B. De, E-mail: g.j.m.vissers@astro.uio.no [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway)

2015-10-10

Ellerman bombs (EBs) are transient brightenings of the extended wings of the solar Balmer lines in emerging active regions. We describe their properties in the ultraviolet lines sampled by the Interface Region Imaging Spectrograph (IRIS), using simultaneous imaging spectroscopy in Hα with the Swedish 1-m Solar Telescope (SST) and ultraviolet images from the Solar Dynamics Observatory for Ellerman bomb detection and identification. We select multiple co-observed EBs for detailed analysis. The IRIS spectra strengthen the view that EBs mark reconnection between bipolar kilogauss fluxtubes with the reconnection and the resulting bi-directional jet located within the solar photosphere and shielded by overlying chromospheric fibrils in the cores of strong lines. The spectra suggest that the reconnecting photospheric gas underneath is heated sufficiently to momentarily reach stages of ionization normally assigned to the transition region and the corona. We also analyze similar outburst phenomena that we classify as small flaring arch filaments and ascribe to reconnection at a higher location. They have different morphologies and produce hot arches in million-Kelvin diagnostics.

Air-sea interaction in the tropical Pacific Ocean

Science.gov (United States)

Allison, L. J.; Steranka, J.; Holub, R. J.; Hansen, J.; Godshall, F. A.; Prabhakara, C.

1972-01-01

Charts of 3-month sea surface temperature (SST) anomalies in the eastern tropical Pacific Ocean were produced for the period 1949 to 1970. The anomalies along the United States and South American west coasts and in the eastern tropical Pacific appeared to be oscillating in phase during this period. Similarly, the satellite-derived cloudiness for each of four quadrants of the Pacific Ocean (130 deg E to 100 deg W, 30 deg N to 25 deg S) appeared to be oscillating in phase. In addition, a global tropical cloudiness oscillation from 30 deg N to 30 deg S was noted from 1965 to 1970, by using monthly satellite television nephanalyses. The SST anomalies were found to have a good degree of correlation both positive and negative with the following monthly geophysical parameters: (1) satellite-derived cloudiness, (2) strength of the North and South Pacific semipermanent anticyclones, (3) tropical Pacific island rainfall, and (4) Darwin surface pressure. Several strong direct local and crossequatorial relationships were noted. In particular, the high degree of correlation between the tropical island rainfall and the SST anomalies (r = +0.93) permitted the derivation of SST's for the tropical Pacific back to 1905. The close occurrence of cold tropical SST and North Pacific 700-mb positive height anomalies with central United States drought conditions was noted.

Rainfall variations over the Bay of Bengal and southern Tibetan Plateau and their connections with different tropical forcing during the early and middle summer

Science.gov (United States)

Wang, Z.; Yang, S.

2016-12-01

Strong rainfall always occurs in the South Asia region during the summer monsoon time (May-September), especially over the Bay of Bengal (BOB) and southern Tibetan Plateau (STP). The latent heating associated with such rainfall drives large-scale circulation and further influences weather and climate anomalies over the world. Few studies have focused on the intraseasonal difference of the rainfall interannual variations. Generally, two precipitation centers appear over the BOB and STP respectively, which are corresponding to the southern and northern upward branches of the South Asian summer monsoon. Our results indicate that the interannual variability of precipitation over the BOB is consistent with that over the STP during the early summer (May-June), but it is contrary during the midsummer (July-August). In early summer, precipitation over the BOB and STP is mainly regulated by the sea surface temperature (SST) anomalies in tropical eastern Pacific (corresponding to the ENSO). Warm SST anomalies in the eastern Pacific weaken upward motion and further precipitation over the BOB and STP through the modulation of zonal walker circulation. However, the tropical forcing exists over the western Maritime Continent (WMC) during midsummer, which induces the contrary variations of rainfall over the BOB and STP. Warm WMC SST anomalies lead to an anticyclone over the BOB, which is unfavourable to the BOB rainfall. While the southwesterlies at the northwest of that anticyclone favor moisture transport to the Tibetan Plateau and thus an enhancement in rainfall over the STP.

How autumn Eurasian snow anomalies affect east asian winter monsoon: a numerical study

Science.gov (United States)

Luo, Xiao; Wang, Bin

2018-03-01

Previous studies have found that snow Eurasian anomalies in autumn can affect East Asian winter monsoon (EAWM), but the mechanisms remain controversial and not well understood. The possible mechanisms by which Eurasian autumn snow anomalies affect EAWM are investigated by numerical experiments with a coupled general circulation model and its atmospheric general circulation model component. The leading empirical orthogonal function mode of the October-November mean Eurasian snow cover is characterized by a uniform anomaly over a broad region of central Eurasia (40°N-65°N, 60°E-140°E). However, the results from a 150-ensemble mean simulation with snow depth anomaly specified in October and November reveal that the Mongolian Plateau and Vicinity (MPV, 40°-55°N, 80°-120°E) is the key region for autumn snow anomalies to affect EAWM. The excessive snow forcing can significantly enhance EAWM and the snowfall over the northwestern China and along the EAWM front zone stretching from the southeast China to Japan. The physical process involves a snow-monsoon feedback mechanism. The excessive autumn snow anomalies over the MPV region can persist into the following winter, and significantly enhance winter snow anomalies, which increase surface albedo, reduce incoming solar radiation and cool the boundary layer air, leading to an enhanced Mongolian High and a deepened East Asian trough. The latter, in turn, strengthen surface northwesterly winds, cooling East Asia and increasing snow accumulation over the MPV region and the southeastern China. The increased snow covers feedback to EAWM system through changing albedo, extending its influence southeastward. It is also found that the atmosphere-ocean coupling process can amplify the delayed influence of Eurasian snow mass anomaly on EAWM. The autumn surface albedo anomalies, however, do not have a lasting "memory" effect. Only if the albedo anomalies are artificially extended into December and January, will the EAWM be

Tropical Atlantic Contributions to Strong Rainfall Variability Along the Northeast Brazilian Coast

Directory of Open Access Journals (Sweden)

G. A. Hounsou-gbo

2015-01-01

Full Text Available Tropical Atlantic (TA Ocean-atmosphere interactions and their contributions to strong variability of rainfall along the Northeast Brazilian (NEB coast were investigated for the years 1974–2008. The core rainy seasons of March-April and June-July were identified for Fortaleza (northern NEB; NNEB and Recife (eastern NEB; ENEB, respectively. Lagged linear regressions between sea surface temperature (SST and pseudo wind stress (PWS anomalies over the entire TA and strong rainfall anomalies at Fortaleza and Recife show that the rainfall variability of these regions is differentially influenced by the dynamics of the TA. When the Intertropical Convergence Zone is abnormally displaced southward a few months prior to the NNEB rainy season, the associated meridional mode increases humidity and precipitation during the rainy season. Additionally, this study shows predictive effect of SST, meridional PWS, and barrier layer thickness, in the Northwestern equatorial Atlantic, on the NNEB rainfall. The dynamical influence of the TA on the June-July ENEB rainfall variability shows a northwestward-propagating area of strong, positively correlated SST from the southeastern TA to the southwestern Atlantic warm pool (SAWP offshore of Brazil. Our results also show predictive effect of SST, zonal PWS, and mixed layer depth, in the SAWP, on the ENEB rainfall.

Edge transport and fluctuation induced turbulence characteristics in early SST-1 plasma

Energy Technology Data Exchange (ETDEWEB)

Kakati, B., E-mail: bharat.kakati@ipr.res.in; Pradhan, S., E-mail: pradhan@ipr.res.in; Dhongde, J.; Semwal, P.; Yohan, K.; Banaudha, M.

2017-02-15

Highlights: • Anomalous particle transport during the high MHD activity at SST-1. • Electrostatic turbulence is modulated by MHD activity at SST-1 tokamak. • Edge floating potential fluctuations shows poloidal long-range cross correlation. - Abstract: Plasma edge transport characteristics are known to be heavily influenced by the edge fluctuation induced turbulences. These characteristics play a critical role towards the confinement of plasma column in a Tokamak. The edge magnetic fluctuations and its subsequent effect on electrostatic fluctuations have been experimentally investigated for the first time at the edge of the SST-1 plasma column. This paper reports the correlations that exist and is experimentally been observed between the edge densities and floating potential fluctuations with the magnetic fluctuations. The edge density and floating potential fluctuations have been measured with the help of poloidally separated Langmuir probes, whereas the magnetic fluctuations have been measured with poloidally spaced Mirnov coils. Increase in magnetic fluctuations associated with enhanced MHD activities has been found to increase the floating potential and ion saturation current. These observations indicate electrostatic turbulence getting influenced with the MHD activities and reveal the edge anomalous particle transport during SST-1 tokamak discharge. Large-scale coherent structures have been observed in the floating potential fluctuations, indicating long-distance cross correlation in the poloidal directions. From bispectral analysis, a strong nonlinear coupling among the floating potential fluctuations is observed in the low-frequency range about 0–15 kHz.

Wagging the Pacific Dog by its Indian Tail? : A west Indian Ocean Precursor to El Niño

NARCIS (Netherlands)

Wieners, C.E.

2018-01-01

Cool Sea Surface Temperature (SST) anomalies tend to prevail in the Seychelles Dome region (Southwest Indian Ocean, NE of Madagascar) during the Northern hemisphere summer-autumn 1.5 years before El Niño. This West Indian Ocean precursor might potentially help to predict El Niño/Southern Oscillation

MAPS OF IMPACT ZONES OF REGION OF THE KURSK MAGNETIC ANOMALY FOR THE ECOLOGICAL ATLAS OF RUSSIA

Directory of Open Access Journals (Sweden)

O. I. Markova

2016-01-01

Full Text Available Maps of several impact zones of the Russian Federation are included in the Ecological Atlas of Russia. These zones are characterized by the high degree of the development of the mining industry and respectively by high level of the anthropogenic impact on the environment. One of these regions is the region of the Kursk Magnetic Anomaly (КМА, where the extractive industry is most developed in separate areas of Kursk and Belgorod regions. During a long time the iron ore is mined here both open and closed methods. The general map of the Kursk Magnetic Anomaly lets to see in complex all iron ore regions and deposits and to reveal most environmentally dangerous of them as well as to evaluate the significance of deposits. Large-scale maps let to consider diverse anthropogenic changes of the environment caused by the extractive industry as well as by related industries. In regions of the intensive development of the mining industry with great areas included in the process of the industrial production and the storage of wastes take place the movement of huge masses of ground, the destruction and the degradation of the vegetation cover, the destruction of the traditional structure of settlements and the disappearance of most settlements. In example of areas of impact zones processes of the disappearance of rural settlements, of the urban sprawl and of displacement of the agriculture by the extractive industry can be seen firsthand. A registration of the development of this process is very important in the planning of the development of territories, all the more so the region of the Kursk Magnetic Anomaly has fertile chernozem soils which are not very abundant in the territory of the Russian Federation. Mining complexes are surrounded by a range of related companies serving the production and livelihoods of the population. These companies also have an impact on the environment, sometimes significantly changing it. Serious changes

On the relation between ionospheric winter anomalies and solar wind

International Nuclear Information System (INIS)

Rumi, G.C.

2001-01-01

There are two different winter anomalies. A small one that appears in connection with ionization at relatively low latitudes in the bottom of the D-region of the ionosphere. There, the electron densities in the winter happen to be less than should be expected. On the other hand, the classic winter anomaly is present when in the winter the upper D-region, again at relatively low latitudes, has more ionization than should be expected. Both these effects are due to the slant compression of the geomagnetic field produced by the solar wind in the wind in the winter season (which is, of course, the summer season when reference is made to events in the other hemisphere). It is shown that the small winter anomaly is a consequence of a hemispheric imbalance in the flux of galactic cosmic rays determined by the obliquely distorted geomagnetic field. It is shown that the standard winter anomaly can be ascribed to the influx of a super solar wind, which penetrates into the Earth's polar atmosphere down to E-region, heights and, duly concentrated through a funneling action at the winter pole of the distorted geomagnetic field, slows down the winter polar vortex. An equatorward motion of the polar air with its content of nitric oxide brings about the excess of ionization in the upper D-region at lower latitudes. The experimentally observed rhythmic recurrence of the upper winter anomaly is correlated to a possible rhythmic recurrence of the super solar wind. The actual detection of the upper winter anomaly could yield some information on the velocity of the basic solar wind. A by-product of the present analysis, the determination of Γ, the coefficient of collisional detachment of the electrons from the O 2 - ions, is presented in the Appendix

On the relation between ionospheric winter anomalies and solar wind

Energy Technology Data Exchange (ETDEWEB)

Rumi, G.C. [Lecco, (Italy)

2001-06-01

There are two different winter anomalies. A small one that appears in connection with ionization at relatively low latitudes in the bottom of the D-region of the ionosphere. There, the electron densities in the winter happen to be less than should be expected. On the other hand, the classic winter anomaly is present when in the winter the upper D-region, again at relatively low latitudes, has more ionization than should be expected. Both these effects are due to the slant compression of the geomagnetic field produced by the solar wind in the wind in the winter season (which is, of course, the summer season when reference is made to events in the other hemisphere). It is shown that the small winter anomaly is a consequence of a hemispheric imbalance in the flux of galactic cosmic rays determined by the obliquely distorted geomagnetic field. It is shown that the standard winter anomaly can be ascribed to the influx of a super solar wind, which penetrates into the Earth's polar atmosphere down to E-region, heights and, duly concentrated through a funneling action at the winter pole of the distorted geomagnetic field, slows down the winter polar vortex. An equatorward motion of the polar air with its content of nitric oxide brings about the excess of ionization in the upper D-region at lower latitudes. The experimentally observed rhythmic recurrence of the upper winter anomaly is correlated to a possible rhythmic recurrence of the super solar wind. The actual detection of the upper winter anomaly could yield some information on the velocity of the basic solar wind. A by-product of the present analysis, the determination of {gamma}, the coefficient of collisional detachment of the electrons from the O{sub 2} {sup -} ions, is presented in the Appendix.

Upgradation in SCADA and PLC of existing LN{sub 2} control system for SST-1

Energy Technology Data Exchange (ETDEWEB)

Panchal, Pradip, E-mail: pradip@ipr.res.in; Mahesuria, Gaurang; Panchal, Rohit; Patel, Rakesh; Sonara, Dashrath; Pitroda, Dipen; Nimavat, Hiren; Tanna, Vipul; Pradhan, Subrata

2016-11-15

Highlights: • The control system of LN{sub 2} Management System of SST-1 is designed on PLC and SCADA. • The implementation and results of up-gradation in PLC and SCADA are reported. • The up-gradation in PLC and SCADA has improved the reliability & availability of SST-1 LN{sub 2} system. - Abstract: Helium Refrigerator/Liquefier system of Steady State Superconducting Tokamak (SST-1) incorporates Liquid Nitrogen (LN{sub 2}) pre-cooling system. LN{sub 2} is used for 80 K thermal shields of SST-1, current feeder system and integrated flow distribution and control system. The LN{sub 2} management system is distributed system and requires automatic control. Initially LN{sub 2} control system had Citect based Supervisory Control and Data Acquisition (SCADA) and Koyo make Programmable Logic Controller (PLC). With the passage of time and due to unavailability of their hardware, it is being obsoleted. So, the requirements of new PLC and SCADA systems have been envisaged to make uninterruptable operation of SST-1 cryogenic system. Therefore, Wonderware SCADA and Schneider Electric make PLC is programmed to replace Citect SCADA and Koyo PLC. New control features have been added in upgraded control system for better management of LN{sub 2} system. This upgradation of SCADA and PLC is completed, tested successfully and in operation. Operational performance highlights of the new upgraded system are presented in this paper.

SST, Aqua MODIS, NPP, 0.025 degrees, Pacific Ocean, Daytime

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch provides SST data from NASA's Aqua Spacecraft. Measurements are gathered by the Moderate Resolution Imaging Spectroradiometer (MODIS) carried aboard...

Evidence for cosmic ray modulation in temperature records from the South Atlantic Magnetic Anomaly region

Energy Technology Data Exchange (ETDEWEB)

Frigo, E. [Sao Paulo Univ. (Brazil). Dept. de Geofisica; Federal do Pampa Univ., Cacapava do Sul (Brazil); Pacca, I.G. [Sao Paulo Univ. (Brazil). Dept. de Geofisica; Pereira-Filho, A.J. [Sao Paulo Univ. (Brazil). Dept. de Ciencias Atmosfericas; Rampelloto, P.H. [Federal do Pampa Univ., Sao Gabriel (Brazil); Rigozo, N.R. [Instituto Nacional de Pesquisas Espaciais, Sao Jose dos Campos (Brazil). Div. de Geofisica Espacial

2013-11-01

Possible direct or indirect climatic effects related to solar variability and El Nino-Southern Oscillation (ENSO) were investigated in the southern Brazil region by means of the annual mean temperatures from four weather stations 2 degrees of latitude apart over the South Atlantic Magnetic Anomaly (SAMA) region. Four maximum temperature peaks are evident at all stations in 1940, 1958, 1977 and 2002. A spectral analysis indicates the occurrence of periodicities between 2 and 7 yr, most likely associated with ENSO, and periodicities of approximately 11 and 22 yr, normally associated with solar variability. Cross-wavelet analysis indicated that the signal associated with the 22 yr solar magnetic cycle was more persistent in the last decades, while the 11 yr sunspot cycle and ENSO periodicities were intermittent. Phase-angle analysis revealed that temperature variations and the 22 yr solar cycle were in anti-phase near the SAMA center. Results show an indirect indication of possible relationships between the variability of galactic cosmic rays and climate change on a regional scale.

ON THE RELATIONSHIP BETWEEN PRECIPITATION ANOMALIES IN THE FIRST RAINING SEASON (APRIL-JUNE) IN SOUTHERN CHINA AND SST OVER OFFSHORE WATERS IN CHINA

Institute of Scientific and Technical Information of China (English)

邓立平; 王谦谦

2002-01-01

Precipitation anomalies in the first raining season of southern China were analyzed,with the suggestion that there are obvious interannual variation of peak values.In the raining season,the general tendency of precipitation is not obvious and the anomalous oscillation is multi-scale.Corresponding to years of more or less precipitation in the raining season,there are sharply opposite distribution across the nation in the simultaneous periods.In addition,by studying the distribution of correlation between anomalous precipitation in southern China in the first raining season and SSTA over offshore waters of China in the preceding period (June ～August of the previous year),a sensitive zone of waters has been found that has steady effect on the precipitation of southern China in the season.Discussions are also made of the sensitive period,its simultaneous SSTA and subsequent anomalous circulation field in relation to precipitation anomalies and simultaneous circulation field in the first raining season of southern China.In the last part of the work,relationship between the SSTA in the sensitive zone and global SSTA is analyzed.A possible mechanism by which SSTA in offshore Chinese waters affects the precipitation anomalies in the first raining season of southern China is put forward.

An Entropy-Assisted Shielding Function in DDES Formulation for the SST Turbulence Model

Directory of Open Access Journals (Sweden)

Ling Zhou

2017-02-01

Full Text Available The intent of shielding functions in delayed detached-eddy simulation methods (DDES is to preserve the wall boundary layers as Reynolds-averaged Navier–Strokes (RANS mode, avoiding possible modeled stress depletion (MSD or even unphysical separation due to grid refinement. An entropy function fs is introduced to construct a DDES formulation for the k-ω shear stress transport (SST model, whose performance is extensively examined on a range of attached and separated flows (flat-plate flow, circular cylinder flow, and supersonic cavity-ramp flow. Two more forms of shielding functions are also included for comparison: one that uses the blending function F2 of SST, the other which adopts the recalibrated shielding function fd_cor of the DDES version based on the Spalart-Allmaras (SA model. In general, all of the shielding functions do not impair the vortex in fully separated flows. However, for flows including attached boundary layer, both F2 and the recalibrated fd_cor are found to be too conservative to resolve the unsteady flow content. On the other side, fs is proposed on the theory of energy dissipation and independent on from any particular turbulence model, showing the generic priority by properly balancing the need of reserving the RANS modeled regions for wall boundary layers and generating the unsteady turbulent structures in detached areas.

Characterization of NPP Visible/Infrared Imager Radiometer Suite (VIIRS) Reflective Solar Bands Dual Gain Anomaly

Science.gov (United States)

Lee, Shihyan; McIntire, Jeff; Oudari, Hassan

2012-01-01

The Visible/Infrared Imager Radiometer Suite (VIIRS) contains six dual gain bands in the reflective solar spectrum. The dual gain bands are designed to switch gain mode at pre-defined thresholds to achieve high resolution at low radiances while maintaining the required dynamic range for science. During pre-launch testing, an anomaly in the electronic response before transitioning from high to low gain was discovered and characterized. On-orbit, the anomaly was confirmed using MODIS data collected during Simultaneous Nadir Overpasses (SNOs). The analysis of the Earth scene data shows that dual gain anomaly can be determined at the orbital basis. To characterize the dual gain anomaly, the anomaly region and electronic offsets were tracked per week during the first 8 month of VIIRS operation. The temporal analysis shows the anomaly region can drift 20 DN and is impacted by detectors DC Restore. The estimated anomaly flagging regions cover 2.5 % of the high gain dynamic range and are consistent with prelaunch and on-orbit LUT. The prelaunch results had a smaller anomaly range (30-50 DN) and are likely the results of more stable electronics from the shorter data collection time. Finally, this study suggests future calibration efforts to focus on the anomaly's impact on science products and possible correction method to reduce uncertainties.

Seasonal variation of sea surface temperature in the Bay of Bengal during 1992 as derived from NOAA-AVHRR SST data

Digital Repository Service at National Institute of Oceanography (India)

Murty, V.S.N.; Subrahmanyam, B.; Rao, L.V.G.; Reddy, G.V.

. The spatial variation of Standard Deviation of SST bias was particularly high (less than 0.7) in the western Bay when compared to other parts of the Bay of Bengal. The monthly maps of AVHRR SST clearly depicted the seasonal cycle of SST showing the well known...

GHRSST Level 2P USA NAVOCEANO GOES11 SST:1

Data.gov (United States)

National Aeronautics and Space Administration — SST calculated from the IR channels of GOES-11 at full resolution on a half hourly basis. In raw satellite projection, vertically adjacent pixels averaged and read...

GHRSST Level 2P USA NAVOCEANO GOES12 SST:1

Data.gov (United States)

National Aeronautics and Space Administration — SST calculated from the IR channels of GOES-12 at full resolution on a half hourly basis. In raw satellite projection, vertically adjacent pixels averaged and read...

Climate Variability and Oceanographic Settings Associated with Interannual Variability in the Initiation of Dinophysis acuminata Blooms

Directory of Open Access Journals (Sweden)

Henrick Berger

2013-08-01

Full Text Available In 2012, there were exceptional blooms of D. acuminata in early spring in what appeared to be a mesoscale event affecting Western Iberia and the Bay of Biscay. The objective of this work was to identify common climatic patterns to explain the observed anomalies in two important aquaculture sites, the Galician Rías Baixas (NW Spain and Arcachon Bay (SW France. Here, we examine climate variability through physical-biological couplings, Sea Surface Temperature (SST anomalies and time of initiation of the upwelling season and its intensity over several decades. In 2012, the mesoscale features common to the two sites were positive anomalies in SST and unusual wind patterns. These led to an atypical predominance of upwelling in winter in the Galician Rías, and increased haline stratification associated with a southward advection of the Gironde plume in Arcachon Bay. Both scenarios promoted an early phytoplankton growth season and increased stability that enhanced D. acuminata growth. Therefore, a common climate anomaly caused exceptional blooms of D. acuminata in two distant regions through different triggering mechanisms. These results increase our capability to predict intense diarrhetic shellfish poisoning outbreaks in the early spring from observations in the preceding winter.

Design of vessel baking system and thermal radiation shields for SST-1

International Nuclear Information System (INIS)

Kumar, E.R.; Nagabhushana, S.; Pathak, H.A.; Panigrahi, S.; Nath, T.R.; Babu, A.V.S; Gangradey, R.; Patel, R.J.; Saxena, Y.C.

1998-01-01

SST-1 is a Steady State Tokamak with a major radius of 1.1 m, minor radius of 0.2 m and toroidal field of 3.0 T. The toroidal and poloidal field coils of SST-1 are superconducting. One of the main objectives of SST-1 is to demonstrate steady state particle removal and active plasma density control which states the necessity of wall conditioning. The vacuum vessel will be baked up to 525 K by passing hot nitrogen gas through the U - channels welded on the inner surface of vacuum vessel. The required mass flow rate at 5 bar is 0.712 Kg/s to maintain 525 K wall temperature in steady state. Superconducting coils operating at 4.5 K will be protected against thermal radiation from hot surfaces using liquid nitrogen cooled panels operating at 87 K. Maximum 1200 litres/hour liquid nitrogen is required during vessel baking. The design of vacuum vessel baking system and thermal radiation shields and related flow analysis are presented here. (authors)

Design of vessel baking system and thermal radiation shields for SST-1

Energy Technology Data Exchange (ETDEWEB)

Kumar, E.R.; Nagabhushana, S.; Pathak, H.A.; Panigrahi, S.; Nath, T.R.; Babu, A.V.S; Gangradey, R.; Patel, R.J.; Saxena, Y.C. [Institute for Plasma Research, Gandhinagar (India)

1998-07-01

SST-1 is a Steady State Tokamak with a major radius of 1.1 m, minor radius of 0.2 m and toroidal field of 3.0 T. The toroidal and poloidal field coils of SST-1 are superconducting. One of the main objectives of SST-1 is to demonstrate steady state particle removal and active plasma density control which states the necessity of wall conditioning. The vacuum vessel will be baked up to 525 K by passing hot nitrogen gas through the U - channels welded on the inner surface of vacuum vessel. The required mass flow rate at 5 bar is 0.712 Kg/s to maintain 525 K wall temperature in steady state. Superconducting coils operating at 4.5 K will be protected against thermal radiation from hot surfaces using liquid nitrogen cooled panels operating at 87 K. Maximum 1200 litres/hour liquid nitrogen is required during vessel baking. The design of vacuum vessel baking system and thermal radiation shields and related flow analysis are presented here. (authors)

Vertebral column anomalies in Indo-Pacific and Atlantic humpback dolphins Sousa spp.

Science.gov (United States)

Weir, Caroline R; Wang, John Y

2016-08-09

Conspicuous vertebral column abnormalities in humpback dolphins (genus Sousa) were documented for the first time during 3 photo-identification field studies of small populations in Taiwan, Senegal and Angola. Seven Taiwanese humpback dolphins S. chinensis taiwanensis with vertebral column anomalies (lordosis, kyphosis or scoliosis) were identified, along with 2 possible cases of vertebral osteomyelitis. There was evidence from several individuals photographed over consecutive years that the anomalies became more pronounced with age. Three Atlantic humpback dolphins S. teuszii were observed with axial deviations of the vertebral column (lordosis and kyphosis). Another possible case was identified in a calf, and 2 further animals were photographed with dorsal indents potentially indicative of anomalies. Vertebral column anomalies of humpback dolphins were predominantly evident in the lumbo-caudal region, but one Atlantic humpback dolphin had an anomaly in the cervico-thoracic region. Lordosis and kyphosis occurred simultaneously in several individuals. Apart from the described anomalies, all dolphins appeared in good health and were not obviously underweight or noticeably compromised in swim speed. This study presents the first descriptions of vertebral column anomalies in the genus Sousa. The causative factors for the anomalies were unknown in every case and are potentially diverse. Whether these anomalies result in reduced fitness of individuals or populations merits attention, as both the Taiwanese and Atlantic humpback dolphin are species of high conservation concern.

MAGSAT anomaly field inversion and interpretation for the US

Science.gov (United States)

Mayhew, M. A. (Principal Investigator)

1982-01-01

Long wavelength anomalies in the total magnetic field measured by MAGSAT over the United States and adjacent areas are inverted to an equivalent layer crustal magnetization distribution. The model is based on an equal area dipole grid at the Earth's surface. Model resolution, defined as the closest dipole spacing giving a solution having physical significance, is about 220 km for MAGSAT data in the elevation range 300-500 km. The magnetization contours correlate well with large scale tectonic provinces. A higher resolution (200 km) model based on relatively noise free synthetic "pseudodata" is also presented. Magnetic anomaly component data measured by MAGSAT is compared with synthetic anomaly component fields arising from an equivalent source dipole array at the Earth's surface generated from total field anomaly data alone. An excellent inverse correlation between apparent magnetization and heat flow in the western U.S. is demonstrated. A regional heat flow map which is presented and compared with published maps, predicts high heat flow in Nebraska and the Dakotas, suggesting the presence of a "blind" geothermal area of regional extent.

Indo-Pacific Variability on Seasonal to Multidecadal Time Scales. Part I: Intrinsic SST Modes in Models and Observations

Science.gov (United States)

Slawinska, Joanna; Giannakis, Dimitrios

2017-07-01

The variability of Indo-Pacific SST on seasonal to multidecadal timescales is investigated using a recently introduced technique called nonlinear Laplacian spectral analysis (NLSA). Through this technique, drawbacks associated with ad hoc pre-filtering of the input data are avoided, enabling recovery of low-frequency and intermittent modes not previously accessible via classical approaches. Here, a multiscale hierarchy of spatiotemporal modes is identified for Indo-Pacific SST in millennial control runs of CCSM4 and CM3 and in HadISST data. On interannual timescales, a mode with spatiotemporal patterns corresponding to the fundamental component of ENSO emerges, along with ENSO-modulated annual modes consistent with combination mode theory. The ENSO combination modes also feature prominent activity in the Indian Ocean, explaining significant fraction of the SST variance in regions associated with the Indian Ocean dipole. A pattern resembling the tropospheric biennial oscillation emerges in addition to ENSO and the associated combination modes. On multidecadal timescales, the dominant NLSA mode in the model data is predominantly active in the western tropical Pacific. The interdecadal Pacific oscillation also emerges as a distinct NLSA mode, though with smaller explained variance than the western Pacific multidecadal mode. Analogous modes on interannual and decadal timescales are also identified in HadISST data for the industrial era, as well as in model data of comparable timespan, though decadal modes are either absent or of degraded quality in these datasets.

The role of ocean-atmosphere interaction in Typhoon Sinlaku (2008) using a regional coupled data assimilation system

Science.gov (United States)

Wada, Akiyoshi; Kunii, Masaru

2017-05-01

For improving analyses of tropical cyclone (TC) and sea surface temperature (SST) and thereby TC simulations, a regional mesoscale strongly coupled atmosphere-ocean data assimilation system was developed with the local ensemble transform Kalman filter (LETKF) implemented with the Japan Meteorological Agency's nonhydrostatic model (NHM) coupled with a multilayer ocean model and the third-generation ocean wave model. The NHM-LETKF coupled data assimilation system was applied to Typhoon Sinlaku (2008) along with the original NHM-LETKF system to investigate the sensitivity of Sinlaku to SST assimilation with the Level 2 Pre-processed (L2P) standard product of satellite SST. SST calculated in the coupled-assimilation experiment with the coupled data assimilation system and the satellite SST (CPL) showed a better correlation with Optimally Interpolated SST than SST used in the control experiment with the original NHM-LETKF (CNTL) and SST calculated in the succession experiment with the coupled system without satellite SST (SUCC). The time series in the CPL experiment well captured the variation in the SST observed at the Kuroshio Extension Observation buoy site. In addition, TC-induced sea surface cooling was analyzed more realistically in the CPL experiment than that in the CNTL and SUCC experiments. However, the central pressure analyzed in each three experiments was overestimated compared with the Regional Specialized Meteorological Center Tokyo best-track central pressure, mainly due to the coarse horizontal resolution of 15 km. The 96 h TC simulations indicated that the CPL experiment provided more favorable initial and boundary conditions than the CNTL experiment to simulate TC tracks more accurately.

Seasonal Mean SST images of Stellwagen Bank National Marine Sanctuary

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Average seasonal sea surface temperatures http://podaac.jpl.nasa.gov/ Naming Convention: XXXX_SSSYYYY_SST.tif XXXX=location (Stell) SSS=season (FAL=fall, SPR=spring,...

DeepAnomaly: Combining Background Subtraction and Deep Learning for Detecting Obstacles and Anomalies in an Agricultural Field

Directory of Open Access Journals (Sweden)

Peter Christiansen

2016-11-01

Full Text Available Convolutional neural network (CNN-based systems are increasingly used in autonomous vehicles for detecting obstacles. CNN-based object detection and per-pixel classification (semantic segmentation algorithms are trained for detecting and classifying a predefined set of object types. These algorithms have difficulties in detecting distant and heavily occluded objects and are, by definition, not capable of detecting unknown object types or unusual scenarios. The visual characteristics of an agriculture field is homogeneous, and obstacles, like people, animals and other obstacles, occur rarely and are of distinct appearance compared to the field. This paper introduces DeepAnomaly, an algorithm combining deep learning and anomaly detection to exploit the homogenous characteristics of a field to perform anomaly detection. We demonstrate DeepAnomaly as a fast state-of-the-art detector for obstacles that are distant, heavily occluded and unknown. DeepAnomaly is compared to state-of-the-art obstacle detectors including “Faster R-CNN: Towards Real-Time Object Detection with Region Proposal Networks” (RCNN. In a human detector test case, we demonstrate that DeepAnomaly detects humans at longer ranges (45–90 m than RCNN. RCNN has a similar performance at a short range (0–30 m. However, DeepAnomaly has much fewer model parameters and (182 ms/25 ms = a 7.28-times faster processing time per image. Unlike most CNN-based methods, the high accuracy, the low computation time and the low memory footprint make it suitable for a real-time system running on a embedded GPU (Graphics Processing Unit.

Measuring the potential utility of seasonal climate predictions

Science.gov (United States)

Tippett, Michael K.; Kleeman, Richard; Tang, Youmin

2004-11-01

Variation of sea surface temperature (SST) on seasonal-to-interannual time-scales leads to changes in seasonal weather statistics and seasonal climate anomalies. Relative entropy, an information theory measure of utility, is used to quantify the impact of SST variations on seasonal precipitation compared to natural variability. An ensemble of general circulation model (GCM) simulations is used to estimate this quantity in three regions where tropical SST has a large impact on precipitation: South Florida, the Nordeste of Brazil and Kenya. We find the yearly variation of relative entropy is strongly correlated with shifts in ensemble mean precipitation and weakly correlated with ensemble variance. Relative entropy is also found to be related to measures of the ability of the GCM to reproduce observations.

Tropospheric biennial oscillation and south Asian summer monsoon rainfall in a coupled model

KAUST Repository

Konda, Gopinadh; Chowdary, Jasti S.; Srinivas, G; Gnanaseelan, C; Parekh, Anant; Attada, Raju; Rama Krishna, S S V S

2018-01-01

In this study Tropospheric Biennial Oscillation (TBO) and south Asian summer monsoon rainfall are examined in the National Centers for Environmental Prediction (NCEP) Climate Forecast System (CFSv2) hindcast. High correlation between the observations and model TBO index suggests that the model is able to capture most of the TBO years. Spatial patterns of rainfall anomalies associated with positive TBO over the south Asian region are better represented in the model as in the observations. However, the model predicted rainfall anomaly patterns associated with negative TBO years are improper and magnitudes are underestimated compared to the observations. It is noted that positive (negative) TBO is associated with La Niña (El Niño) like Sea surface temperature (SST) anomalies in the model. This leads to the fact that model TBO is El Niño-Southern Oscillation (ENSO) driven, while in the observations Indian Ocean Dipole (IOD) also plays a role in the negative TBO phase. Detailed analysis suggests that the negative TBO rainfall anomaly pattern in the model is highly influenced by improper teleconnections allied to IOD. Unlike in the observations, rainfall anomalies over the south Asian region are anti-correlated with IOD index in CFSv2. Further, summer monsoon rainfall over south Asian region is highly correlated with IOD western pole than eastern pole in CFSv2 in contrast to the observations. Altogether, the present study highlights the importance of improving Indian Ocean SST teleconnections to south Asian summer rainfall in the model by enhancing the predictability of TBO. This in turn would improve monsoon rainfall prediction skill of the model.

Tropospheric biennial oscillation and south Asian summer monsoon rainfall in a coupled model

Science.gov (United States)

Konda, Gopinadh; Chowdary, J. S.; Srinivas, G.; Gnanaseelan, C.; Parekh, Anant; Attada, Raju; Rama Krishna, S. S. V. S.

2018-06-01

In this study Tropospheric Biennial Oscillation (TBO) and south Asian summer monsoon rainfall are examined in the National Centers for Environmental Prediction (NCEP) Climate Forecast System (CFSv2) hindcast. High correlation between the observations and model TBO index suggests that the model is able to capture most of the TBO years. Spatial patterns of rainfall anomalies associated with positive TBO over the south Asian region are better represented in the model as in the observations. However, the model predicted rainfall anomaly patterns associated with negative TBO years are improper and magnitudes are underestimated compared to the observations. It is noted that positive (negative) TBO is associated with La Niña (El Niño) like Sea surface temperature (SST) anomalies in the model. This leads to the fact that model TBO is El Niño-Southern Oscillation (ENSO) driven, while in the observations Indian Ocean Dipole (IOD) also plays a role in the negative TBO phase. Detailed analysis suggests that the negative TBO rainfall anomaly pattern in the model is highly influenced by improper teleconnections allied to IOD. Unlike in the observations, rainfall anomalies over the south Asian region are anti-correlated with IOD index in CFSv2. Further, summer monsoon rainfall over south Asian region is highly correlated with IOD western pole than eastern pole in CFSv2 in contrast to the observations. Altogether, the present study highlights the importance of improving Indian Ocean SST teleconnections to south Asian summer rainfall in the model by enhancing the predictability of TBO. This in turn would improve monsoon rainfall prediction skill of the model.

Tropospheric biennial oscillation and south Asian summer monsoon rainfall in a coupled model

KAUST Repository

Konda, Gopinadh

2018-05-22

In this study Tropospheric Biennial Oscillation (TBO) and south Asian summer monsoon rainfall are examined in the National Centers for Environmental Prediction (NCEP) Climate Forecast System (CFSv2) hindcast. High correlation between the observations and model TBO index suggests that the model is able to capture most of the TBO years. Spatial patterns of rainfall anomalies associated with positive TBO over the south Asian region are better represented in the model as in the observations. However, the model predicted rainfall anomaly patterns associated with negative TBO years are improper and magnitudes are underestimated compared to the observations. It is noted that positive (negative) TBO is associated with La Niña (El Niño) like Sea surface temperature (SST) anomalies in the model. This leads to the fact that model TBO is El Niño-Southern Oscillation (ENSO) driven, while in the observations Indian Ocean Dipole (IOD) also plays a role in the negative TBO phase. Detailed analysis suggests that the negative TBO rainfall anomaly pattern in the model is highly influenced by improper teleconnections allied to IOD. Unlike in the observations, rainfall anomalies over the south Asian region are anti-correlated with IOD index in CFSv2. Further, summer monsoon rainfall over south Asian region is highly correlated with IOD western pole than eastern pole in CFSv2 in contrast to the observations. Altogether, the present study highlights the importance of improving Indian Ocean SST teleconnections to south Asian summer rainfall in the model by enhancing the predictability of TBO. This in turn would improve monsoon rainfall prediction skill of the model.

Monitoring and trend mapping of sea surface temperature (SST) from MODIS data: a case study of Mumbai coast.

Science.gov (United States)

Azmi, Samee; Agarwadkar, Yogesh; Bhattacharya, Mohor; Apte, Mugdha; Inamdar, Arun B

2015-04-01

Sea surface temperature (SST) is one of the most important parameters in monitoring ecosystem health in the marine and coastal environment. Coastal ecosystem is largely dependent on ambient temperature and temperature fronts for marine/coastal habitat and its sustainability. Hence, thermal pollution is seen as a severe threat for ecological health of coastal waters across the world. Mumbai is one of the largest metropolises of the world and faces severe domestic and industrial effluent disposal problem, of which thermal pollution is a major issue with policy-makers and environmental stakeholders. This study attempts to understand the long-term SST variation in the coastal waters off Mumbai, on the western coast of India, and to identify thermal pollution zones. Analysis of SST trends in the near-coastal waters for the pre- and post-monsoon seasons from the year 2004 to the year 2010 has been carried out using Moderate Resolution Imaging Spectro-radiometer (MODIS) Thermal Infra-red (TIR) bands. SST is calculated with the help of bands 31 and 32 using split window method. Several statistical operations were then applied to find the seasonal averages in SST and the standard deviation of SST in the study area. Maximum variation in SST was found within a perpendicular distance of 5 km from the shoreline during the study period. Also, a warm water mass was found to form consistently off coast during the winter months. Several anthropogenic sources of thermal pollution could be identified which were found to impact various locations along the coast.

Regional mantle upwelling on Venus: The Beta-Atla-Themis anomaly and correlation with global tectonic patterns

Science.gov (United States)

Crumpler, L. S.; Head, J. W.; Aubele, Jayne C.

1993-01-01

The morphology and global distribution of volcanic centers and their association with other geological characteristics offers significant insight into the global patterns of geology, tectonic style, thermal state, and interior dynamics of Venus. Magellan data permit the detailed geological interpretation necessary to address questions about interior dynamics of Venus particularly as they reflect relatively physical, chemical, and thermal conditions of the interior. This paper focuses on the distribution of anomalous concentrations of volcanic centers on Venus and regional patterns of tectonic deformation as it may relate to the identification of global internal anomalies, including mantle dynamic, petrological, or thermal patterns.

A multimodel approach to interannual and seasonal prediction of Danube discharge anomalies

Science.gov (United States)

Rimbu, Norel; Ionita, Monica; Patrut, Simona; Dima, Mihai

2010-05-01

Interannual and seasonal predictability of Danube river discharge is investigated using three model types: 1) time series models 2) linear regression models of discharge with large-scale climate mode indices and 3) models based on stable teleconnections. All models are calibrated using discharge and climatic data for the period 1901-1977 and validated for the period 1978-2008 . Various time series models, like autoregressive (AR), moving average (MA), autoregressive and moving average (ARMA) or singular spectrum analysis and autoregressive moving average (SSA+ARMA) models have been calibrated and their skills evaluated. The best results were obtained using SSA+ARMA models. SSA+ARMA models proved to have the highest forecast skill also for other European rivers (Gamiz-Fortis et al. 2008). Multiple linear regression models using large-scale climatic mode indices as predictors have a higher forecast skill than the time series models. The best predictors for Danube discharge are the North Atlantic Oscillation (NAO) and the East Atlantic/Western Russia patterns during winter and spring. Other patterns, like Polar/Eurasian or Tropical Northern Hemisphere (TNH) are good predictors for summer and autumn discharge. Based on stable teleconnection approach (Ionita et al. 2008) we construct prediction models through a combination of sea surface temperature (SST), temperature (T) and precipitation (PP) from the regions where discharge and SST, T and PP variations are stable correlated. Forecast skills of these models are higher than forecast skills of the time series and multiple regression models. The models calibrated and validated in our study can be used for operational prediction of interannual and seasonal Danube discharge anomalies. References Gamiz-Fortis, S., D. Pozo-Vazquez, R.M. Trigo, and Y. Castro-Diez, Quantifying the predictability of winter river flow in Iberia. Part I: intearannual predictability. J. Climate, 2484-2501, 2008. Gamiz-Fortis, S., D. Pozo

INITIAL SINGLE-SHELL TANK (SST) SYSTEM PERFORMANCE ASSESSMENT OF THE HANFORD SITE

International Nuclear Information System (INIS)

JARAYSI, M.N.

2007-01-01

The ''Initial Single-Shell Tank System Performance Assessment for the Hanford Site [1] (SST PA) presents the analysis of the long-term impacts of residual wastes assumed to remain after retrieval of tank waste and closure of the SST farms at the US Department of Energy (DOE) Hanford Site. The SST PA supports key elements of the closure process agreed upon in 2004 by DOE, the Washington State Department of Ecology (Ecology), and the US Environmental Protection Agency (EPA). The SST PA element is defined in Appendix I of the ''Hanford Federal Facility Agreement and Consent Order'' (HFFACO) (Ecology et al. 1989) [2], the document that establishes the overall closure process for the SST and double-shell tank (DST) systems. The approach incorporated in the SST PA integrates substantive features of both hazardous and radioactive waste management regulations into a single analysis. The defense-in-depth approach used in this analysis defined two major engineering barriers (a surface barrier and the grouted tank structure) and one natural barrier (the vadose zone) that will be relied on to control waste release into the accessible environment and attain expected performance metrics. The analysis evaluates specific barrier characteristics and other site features that influence contaminant migration by the various pathways. A ''reference'' case and a suite of sensitivity/uncertainty cases are considered. The ''reference case'' evaluates environmental impacts assuming central tendency estimates of site conditions. ''Reference'' case analysis results show residual tank waste impacts on nearby groundwater, air resources; or inadvertent intruders to be well below most important performance objectives. Conversely, past releases to the soil, from previous tank farm operations, are shown to have groundwater impacts that re significantly above most performance objectives. Sensitivity/uncertainty cases examine single and multiple parameter variability along with plausible alternatives

[99mTc]Demotate 2 in the detection of sst2-positive tumours: a preclinical comparison with [111In]DOTA-tate

International Nuclear Information System (INIS)

Maina, Theodosia; Nock, Berthold A.; Cordopatis, Paul; Bernard, Bert F.; Breeman, Wout A.P.; Gameren, Arthur van; Berg, Ria van den; Krenning, Eric P.; Jong, Marion de; Reubi, Jean-Claude

2006-01-01

The aim of this study was to evaluate [ 99m Tc]Demotate 2 ([ 99m Tc-N 4 0-1 ,Asp 0 ,Tyr 3 ]octreotate) as a candidate for in vivo imaging of sst 2 -positive tumours and to compare it with [ 111 In]DOTA-tate ([ 111 In-DOTA 0 ,Tyr 3 ]octreotate). Labelling of Demotate 2 with 99m Tc was performed at room temperature using SnCl 2 as reductant in the presence of citrate at alkaline pH. Radiochemical analysis involved ITLC and HPLC methods. Peptide conjugate affinities for sst 2 were determined by receptor autoradiography on rat brain cortex sections using [DOTA 0 , 125 I-Tyr 3 ]octreotate as the radioligand. The affinity profile of Demotate 2 for human sst 1 -sst 5 was studied by receptor autoradiography in cell preparations using the universal somatostatin radioligand [ 125 I][Leu 8 ,(D)Trp 22 ,Tyr 25 ]somatostatin-28. The internalisation rates of [ 99m Tc]Demotate 2 and [ 111 In]DOTA-tate were compared in sst 2 -positive and -negative control cell lines. Biodistribution of radiopeptides was studied in male Lewis rats bearing CA20948 tumours. Peptide conjugates showed selectivity and a high affinity binding for sst 2 (Demotate 2 IC 50 =3.2 nM and DOTA-tate IC 50 =5.4 nM). [ 99m Tc]Demotate 2, like [ 111 In]DOTA-tate, internalised rapidly in all sst 2 -positive cells tested, but not in sst 2 -negative control cells. After injection in CA20948 tumour-bearing rats both radiopeptides showed high and specific uptake in the sst 2 -positive organs and in the implanted tumour and rapid excretion from non-target tissues via the kidneys. [ 99m Tc]Demotate 2, similarly to the known sst 2 -targeting agent [ 111 In]DOTA-tate, showed promising biological qualities for application in the scintigraphy of sst 2 -positive tumours. (orig.)

GHRSST Level 4 Denmark DMI North Sea Baltic SST:1

Data.gov (United States)

National Aeronautics and Space Administration — The L4 analysis is based upon nighttime GHRSST L2P subskin SST observations from several satellites and instruments such as: AMSRE, ATS_NR_2P, AVHRR18_G,...

Understanding the effect of an excessive cold tongue bias on projecting the tropical Pacific SST warming pattern in CMIP5 models

Science.gov (United States)

Ying, Jun; Huang, Ping; Lian, Tao; Tan, Hongjian

2018-05-01

An excessive cold tongue is a common bias among current climate models, and considered an important source of bias in projections of tropical Pacific climate change under global warming. Specifically, the excessive cold tongue bias is closely related to the tropical Pacific SST warming (TPSW) pattern. In this study, we reveal that two processes are the critical mechanisms by which the excessive cold tongue bias influences the projection of the TPSW pattern, based on 32 models from phase 5 of Coupled Model Intercomparison Projection (CMIP5). On the one hand, by assuming that the shortwave (SW) radiation to SST feedback is linearly correlated to the cold tongue SST, the excessive cold tongue bias can induce an overly weak negative SW-SST feedback in the central Pacific, which can lead to a positive SST warming bias in the central to western Pacific (around 150°E-140°W). Moreover, the overly weak local atmospheric dynamics response to SST is a key process of the overly weak SW-SST feedback, compared with the cloud response to atmospheric dynamics and the SW radiation response to cloud. On the other hand, the overly strong ocean zonal overturning circulation associated with the excessive cold tongue bias results in an overestimation of the ocean dynamical thermostat effect, with enhanced ocean stratification under global warming, leading to a negative SST warming bias in the central and eastern Pacific (around 170°W-120°W). These two processes jointly form a positive SST warming bias in the western Pacific, contributing to a La Niña-like warming bias. Therefore, we suggest a more realistic climatological cold tongue SST is needed for a more reliable projection of the TPSW pattern.

Understanding of impurity behavior in SST-1 plasmas using visible spectroscopy

International Nuclear Information System (INIS)

Manchanda, Ranjana; Ramaiya, Nilam; Chowdhuri, Malay Bikas; Banerjee, Santanu; Ghosh, Joydeep

2015-01-01

Studies of impurity behavior in SST-1 plasma have been carried out using visible spectroscopic systems installed on the tokomak. This has been carried out using a low resolution and broadband survey spectrometer covering a 350-900 nm wavelength range, 0.5 m visible spectrometer having 600 and 1200 grooves/mm grating coupled with CCD camera and interference filter and photomultiplier (PMT) tube based systems. Temporal evolution of the hydrogen (H α , H β ) and impurities emissions like, C II, C III, O I, O II, O III, O V and a visible Continuum at 536.0 nm have been monitored using the PMT based system to understand impurity charge state evolution during plasma discharges. All systems are absolutely calibrated for impurity influx and plasma parameter estimations. Observed spectral lines in the visible range have been identified to recognize the presence of various impurities in the SST-1 plasmas. Comparison of impurities emission has been made for different plasma currents and toroidal magnetic fields. An analysis has been carried out to understand the impurities activities in plasmas of SST-1 tokomak in presence and absence of installed plasma facing components (PFC). Significantly higher carbon emissions have been observed indicating higher carbon content in the plasma with graphite PFCs installed. (author)

Regimes of seasonal air-sea interaction and implications for performance of forced simulations

Energy Technology Data Exchange (ETDEWEB)

Wu, Renguang [Center for Ocean-Land-Atmosphere Studies, Calverton, MD (United States); Kirtman, Ben P. [Center for Ocean-Land-Atmosphere Studies, Calverton, MD (United States); George Mason University, School of Computational Sciences, Fairfax, VA (United States)

2007-09-15

Sea surface temperature (SST) anomalies can induce anomalous convection through surface evaporation and low-level moisture convergence. This SST forcing of the atmosphere is indicated in a positive local rainfall-SST correlation. Anomalous convection can feedback on SST through cloud-radiation and wind-evaporation effects and wind-induced oceanic mixing and upwelling. These atmospheric feedbacks are reflected in a negative local rainfall-SST tendency correlation. As such, the simultaneous rainfall-SST and rainfall-SST tendency correlations can indicate the nature of local air-sea interactions. Based on the magnitude of simultaneous rainfall-SST and rainfall-SST tendency correlations, the present study identifies three distinct regimes of local air-sea interactions. The relative importance of SST forcing and atmospheric forcing differs in these regimes. In the equatorial central-eastern Pacific and, to a smaller degree, in the western equatorial Indian Ocean, SST forcing dominates throughout the year and the surface heat flux acts mainly as a damping term. In the tropical Indo-western Pacific Ocean regions, SST forcing and atmospheric forcing dominate alternatively in different seasons. Atmospheric forcing dominates in the local warm/rainy season. SST forcing dominates with a positive wind-evaporation feedback during the transition to the cold/dry season. SST forcing also dominates during the transition to the warm/rainy season but with a negative cloud-radiation feedback. The performance of atmospheric general circulation model simulations forced by observed SST is closely linked to the regime of air-sea interaction. The forced simulations have good performance when SST forcing dominates. The performance is low or poor when atmospheric forcing dominates. (orig.)

Environmental Factors Correlated with Culturable Enterococci Concentrations in Tropical Recreational Waters: A Case Study in Escambron Beach, San Juan, Puerto Rico

Directory of Open Access Journals (Sweden)

Abdiel E. Laureano-Rosario

2017-12-01

Full Text Available Enterococci concentration variability at Escambron Beach, San Juan, Puerto Rico, was examined in the context of environmental conditions observed during 2005–2015. Satellite-derived sea surface temperature (SST, turbidity, direct normal irradiance, and dew point were combined with local precipitation, winds, and mean sea level (MSL observations in a stepwise multiple regression analyses (Akaike Information Criteria model selection. Precipitation, MSL, irradiance, SST, and turbidity explained 20% of the variation in observed enterococci concentrations based upon these analyses. Changes in these parameters preceded increases in enterococci concentrations by 24 h up to 11 days, particularly during positive anomalies of turbidity, SST, and 480–960 mm of accumulated (4 days precipitation, which relates to bacterial ecology. Weaker, yet still significant, increases in enterococci concentrations were also observed during positive dew point anomalies. Enterococci concentrations decreased with elevated irradiance and MSL anomalies. Unsafe enterococci concentrations per US EPA recreational water quality guidelines occurred when 4-day cumulative precipitation ranged 481–960 mm; irradiance < 667 W·m−2; daily average turbidity anomaly >0.005 sr−1; SST anomaly >0.8 °C; and 3-day average MSL anomaly <−18.8 cm. This case study shows that satellite-derived environmental data can be used to inform future water quality studies and protect human health.

Gravitational anomalies

Energy Technology Data Exchange (ETDEWEB)

Leutwyler, H; Mallik, S

1986-12-01

The effective action for fermions moving in external gravitational and gauge fields is analyzed in terms of the corresponding external field propagator. The central object in our approach is the covariant energy-momentum tensor which is extracted from the regular part of the propagator at short distances. It is shown that the Lorentz anomaly, the conformal anomaly and the gauge anomaly can be expressed in terms of the local polynomials which determine the singular part of the propagator. (There are no coordinate anomalies). Except for the conformal anomaly, for which we give explicit representations only in dless than or equal to4, we consider an arbitrary number of dimensions.

The extreme 2014 flood in south-western Amazon basin: the role of tropical-subtropical South Atlantic SST gradient

International Nuclear Information System (INIS)

Espinoza, Jhan Carlo; Marengo, José Antonio; Ronchail, Josyane; Carpio, Jorge Molina; Flores, Luís Noriega; Guyot, Jean Loup

2014-01-01

Unprecedented wet conditions are reported in the 2014 summer (December–March) in South-western Amazon, with rainfall about 100% above normal. Discharge in the Madeira River (the main southern Amazon tributary) has been 74% higher than normal (58 000 m 3 s −1 ) at Porto Velho and 380% (25 000 m 3 s −1 ) at Rurrenabaque, at the exit of the Andes in summer, while levels of the Rio Negro at Manaus were 29.47 m in June 2014, corresponding to the fifth highest record during the 113 years record of the Rio Negro. While previous floods in Amazonia have been related to La Niña and/or warmer than normal tropical South Atlantic, the 2014 rainfall and flood anomalies are associated with warm condition in the western Pacific-Indian Ocean and with an exceptionally warm Subtropical South Atlantic. Our results suggest that the tropical and subtropical South Atlantic SST gradient is a main driver for moisture transport from the Atlantic toward south-western Amazon, and this became exceptionally intense during summer of 2014. (letter)

Indian Academy of Sciences Conference Series | Indian Academy of ...

Indian Academy of Sciences (India)

We studied the dynamics of the sea surface temperature (SST) anomaly using a model of the temporal patterns of two sub-regions, mimicking behaviour similar to El Niño Southern Oscillations (ENSO). Specifically, we present the existence, stability, and basins of attraction of the solutions arising in the model system in the ...

Simulation study of induced EMFs and the suppression during SST-1 start-up

Energy Technology Data Exchange (ETDEWEB)

Jain, V., E-mail: vishal@ipr.res.in; Sharma, D.; Vardhrajulu, A.; Gupta, C.N.; Srinivasan, R.; Daniel, R.

2015-11-15

Highlights: • Induced EMFs study in PF coils during SST-1 start up using MATlab simulink. • Integration of wave shaping network to generate practical OT current profile. • This study would protect coil insulation with identifying RC circulating network. • Study of MOV technique for circulation of current through RC. - Abstract: Steady State Superconducting Tokamak (SST-1) comprises of various copper and superconducting coils for generating magnetic field for initiation, providing equilibrium and shaping of plasma in tokamak. In this paper, an attempt is made to study the induced EMF in superconducting poloidal field coils (PF coils) due to fast ramp down of current in ohmic transformer copper coils (OT coils) for SST-1 plasma initiation. The fast ramp down of current, from few kA to zero amperes in just 50–100 ms in OT coils, is required to achieve plasma breakdown and ramp up of plasma current in tokamak. However, it induces nearly 5 kV EMF in one of the SST-1 PF coils that can damage the coil insulation and also bias negatively the electronic switching of power supply. It is necessary to maintain induced EMF below 1 kV in all PF coils for safe operation of SST-1. The induced EMF up to 1 kV can be clamped without any need of protection and circulating current. If the induced EMF is in excess of 1 kV, then it has to allow the circulation of current through RC network for coil protection from overvoltage. These circulating currents in PF coils will affect the shaping of plasma. In this paper, the induced EMF in PF coils are simulated using MATlab simulink for a typical SST-1 current profile of OT coils. Further, this simulation study is used to design the protection system for PF coils. In this paper, the worst-case induced EMF scenario is considered by excluding the effect of passive elements like vacuum vessel and cryostat on mutual coupling parameters. However, the implementation of the EMF suppression scheme need more elaborated study with considering

South American Monsoon: Recent Droughts in the Context of Changing Global Circulation.

Science.gov (United States)

Seth, A.; Fernandes, K.; Camargo, S. J.

2016-12-01

The 2013-2015 drought in Southeast Brazil led to water shortages in São Paulo, the country's most populous city. The observed drought during austral summers of 2013/2014 and 2014/2015 and related large-scale dynamics are examined. The 2013-2014 precipitation deficits were more concentrated in the state of São Paulo, while in 2014-2015 moderate deficits were seen throughout the region. We find that a persistent warm sea surface temperature (SST) anomaly in the western tropical Pacific Ocean was an important driver of drought via atmospheric teleconnection in the two December-February seasons. The warm SST and associated convective heating initiated a wave train across the South Pacific. The resulting anticyclonic geopotential height anomaly over the southwest Atlantic expanded the westward margin of the South Atlantic high and prevented low-pressure systems from entering southeast Brazil from midlatitudes. This mechanism suggests a hemispheric symmetry to that proposed for the recent California drought. A first look at CMIP5 model projections to examine the role of large scale circulation changes to drought in the Sao Paulo region will be presented.

[Surgical treatment of first branchial cleft anomaly].

Science.gov (United States)

Xiao, Hongjun; Kong, Weijia; Gong, Shusheng; Wang, Jibao; Liu, Shiying; Shi, Hong

2005-10-01

To identify the clinical and anatomical presentations and to discuss the guidelines for surgical management of anomalies of the first branchial cleft. Twenty-one patients with first branchial cleft anomalies were treated in our department between January 1994 and December 2004, their clinical data were retrospectively analysed. Surgery was performed on all patients. Among them 13 were males and 8 females, ranging in age from 1.5 to 33 years with an average of 15 years. Anatomically, 3 types of first branchial cleft anomalies were identified: fistulas (n = 17), cysts (n = 2), and fistula combined with cyst (n = 2). Before definitive surgery, soma patients (n = 4) underwent incision and drainage for infection owing to the difficulties in diagnosing this anomaly. Methylthioninium Chloride was used in almost all cases for tracking the fistulous during operation. Wide exposure is necessary in many cases,and a standard parotidectomy incision allows adequate exposure of the anomaly and preservation of the facial nerve. Complete removal without complications depends on a good understanding of regional embryogenesis, an awareness of the different anatomical presentations, and a readiness to identify and protect the facial nerve during resection.

A three-stage hybrid model for regionalization, trends and sensitivity analyses of temperature anomalies in China from 1966 to 2015

Science.gov (United States)

Wu, Feifei; Yang, XiaoHua; Shen, Zhenyao

2018-06-01

Temperature anomalies have received increasing attention due to their potentially severe impacts on ecosystems, economy and human health. To facilitate objective regionalization and examine regional temperature anomalies, a three-stage hybrid model with stages of regionalization, trends and sensitivity analyses was developed. Annual mean and extreme temperatures were analyzed using the daily data collected from 537 stations in China from 1966 to 2015, including the annual mean, minimum and maximum temperatures (Tm, TNm and TXm) as well as the extreme minimum and maximum temperatures (TNe and TXe). The results showed the following: (1) subregions with coherent temperature changes were identified using the rotated empirical orthogonal function analysis and K-means clustering algorithm. The numbers of subregions were 6, 7, 8, 9 and 8 for Tm, TNm, TXm, TNe and TXe, respectively. (2) Significant increases in temperature were observed in most regions of China from 1966 to 2015, although warming slowed down over the last decade. This warming primarily featured a remarkable increase in its minimum temperature. For Tm and TNm, 95% of the stations showed a significant upward trend at the 99% confidence level. TNe increased the fastest, at a rate of 0.56 °C/decade, whereas 21% of the stations in TXe showed a downward trend. (3) The mean temperatures (Tm, TNm and TXm) in the high-latitude regions increased more quickly than those in the low-latitude regions. The maximum temperature increased significantly at high elevations, whereas the minimum temperature increased greatly at middle-low elevations. The most pronounced warming occurred in eastern China in TNe and northwestern China in TXe, with mean elevations of 51 m and 2098 m, respectively. A cooling trend in TXe was observed at the northwestern end of China. The warming rate in TNe varied the most among the subregions (0.63 °C/decade).

GHRSST Level 2P USA NAVOCEANO AVHRR17 Global SST:1

Data.gov (United States)

National Aeronautics and Space Administration — Multi-Channel SST retreivals generated in real-time from NOAA-17 AVHRR Global Area Coverage data. Used operationally in Navy oceanographic analyses and forecasts.

GHRSST Level 2P USA NAVOCEANO AVHRR18 Global SST:1

Data.gov (United States)

National Aeronautics and Space Administration — Multi-Channel SST retreivals generated in real-time from NOAA-18 AVHRR Global Area Coverage data. Used operationally in Navy oceanographic analyses and forecasts.

Holonomy anomalies

International Nuclear Information System (INIS)

Bagger, J.; Nemeschansky, D.; Yankielowicz, S.

1985-05-01

A new type of anomaly is discussed that afflicts certain non-linear sigma models with fermions. This anomaly is similar to the ordinary gauge and gravitational anomalies since it reflects a topological obstruction to the reparametrization invariance of the quantum effective action. Nonlinear sigma models are constructed based on homogeneous spaces G/H. Anomalies arising when the fermions are chiral are shown to be cancelled sometimes by Chern-Simons terms. Nonlinear sigma models are considered based on general Riemannian manifolds. 9 refs

Prevalence of inner ear anomalies among cochlear implant candidates.

Science.gov (United States)

Aldhafeeri, Ahmad M; Alsanosi, Abdulrahman A

2016-10-01

To determine the prevalence of inner ear anomalies and the frequency of different anomaly types among cochlear implant recipients. This study included a retrospective chart review of all patients who received cochlear implants between January 2009 and January 2013 in King Abdulaziz University Hospital cochlear implant program in Riyadh, Saudi Arabia. All subjects underwent thin-cut CT of the temporal bone and MRI. The collected data included age, gender, and CT and MRI findings regarding temporal bone anomalies. Patients with any identified congenital inner ear anomalies were included in the study.  In total, 316 patients' cases were reviewed. Inner ear malformations were identified in 24 patients, which represented a prevalence of 7.5%. Among these 24 patients, 8 (33.3%) presented with a large vestibular aqueduct (LVA), 8 (33.3%) semicircular canal (SCC) dysplasia, 7 (29.1%) classical Mondini deformity, and one (4.1%) cochlear hypoplasia. The prevalence of inner ear anomalies among cochlear implant recipients was 7.5%. This result is consistent with findings worldwide. The most common anomalies were LVA and SCC hypoplasia; by contrast, in other regions, the most common anomaly is either the Mondini deformity, or LVA.

Anomalies

International Nuclear Information System (INIS)

Bardeen, W.A.

1985-08-01

Anomalies have a diverse impact on many aspects of physical phenomena. The role of anomalies in determining physical structure from the amplitude for π 0 decay to the foundations of superstring theory will be reviewed. 36 refs

Systems Engineering Implementation Plan for Single-Shell Tanks (SST) Retrieval Projects

International Nuclear Information System (INIS)

LEONARD, M.W.; HOFFERBER, G.A.

2000-01-01

This document communicates the planned implementation of the Systems Engineering processes and products for the SST retrieval projects as defined in the Systems Engineering Management Plan for the Tank Farm Contractor

Systems Engineering Implementation Plan for Single Shell Tanks (SST) Retrieval Projects

Energy Technology Data Exchange (ETDEWEB)

LEONARD, M.W.; HOFFERBER, G.A.

2000-11-30

This document communicates the planned implementation of the Systems Engineering processes and products for the SST retrieval projects as defined in the Systems Engineering Management Plan for the Tank Farm Contractor.

SST, Aqua MODIS, NPP, 0.05 degrees, Global, Daytime, Science Quality

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch provides SST data from NASA's Aqua Spacecraft. Measurements are gathered by the Moderate Resolution Imaging Spectroradiometer (MODIS) carried aboard...

Relação entre as vazões médias mensais do rio Piancó e as anomalias de temperatura da superfície dos oceanos Atlântico e Pacífico tropical Relationhips between monthly mean stream flow for the Pianco river and tropical Atlantic and Pacific sst anomalies

Directory of Open Access Journals (Sweden)

Manoel F. Gomes Filho

2000-01-01

Full Text Available Apresenta-se, neste trabalho, uma análise estatística baseada em correlações entre as temperaturas globais da superfície do mar (TSM e as descargas do Rio Piancó, no sertão da Paraíba, principal contribuinte do reservatório de Coremas, na região. Os coeficientes globais de correlação foram obtidos entre as temperaturas médias da superfície do mar, para os trimestres de novembro a janeiro e de fevereiro a abril, e as descargas do Rio Piancó no reservatório de Coremas, para cada mês de fevereiro até maio, que compreendem a estação chuvosa na bacia hidrográfica do reservatório. Os resultados mostram correlações significativas entre as TSM das regiões NINO1+2 e NINO3 no Oceano Pacífico. Na área do Atlântico não existe um padrão de correlações bem definido.This paper presents a statistical analysis based on the correlation between the Global Sea Surface Temperatures (SST and the discharge of Piancó river the principal contributor to the Coremas reservoir in the Paraíba State. The global correlation coefficients were obtained between the mean Sea Surface Temperatures (SST for the November to January and February to April trimesters and the volume of water discharged by the Piancó river in the Coremas reservoir for each of the individual months from February to May, the rainy season in the region of the reservoir. The results show the existence of a strong negative correlation between the SST's of the Nino1+2 and Nino3 regions of the Pacific Ocean. For the Atlantic area no well defined pattern of correlation was found.

Timeslice experiments for understanding regional climate projections: applications to the tropical hydrological cycle and European winter circulation

Science.gov (United States)

Chadwick, Robin; Douville, Hervé; Skinner, Christopher B.

2017-11-01

A set of atmosphere-only timeslice experiments are described, designed to examine the processes that cause regional climate change and inter-model uncertainty in coupled climate model responses to CO_2 forcing. The timeslice experiments are able to reproduce the pattern of regional climate change in the coupled models, and are applied here to two cases where inter-model uncertainty in future projections is large: the tropical hydrological cycle, and European winter circulation. In tropical forest regions, the plant physiological effect is the largest cause of hydrological cycle change in the two models that represent this process. This suggests that the CMIP5 ensemble mean may be underestimating the magnitude of water cycle change in these regions, due to the inclusion of models without the plant effect. SST pattern change is the dominant cause of precipitation and circulation change over the tropical oceans, and also appears to contribute to inter-model uncertainty in precipitation change over tropical land regions. Over Europe and the North Atlantic, uniform SST increases drive a poleward shift of the storm-track. However this does not consistently translate into an overall polewards storm-track shift, due to large circulation responses to SST pattern change, which varies across the models. Coupled model SST biases influence regional rainfall projections in regions such as the Maritime Continent, and so projections in these regions should be treated with caution.

Analyzing Spatiotemporal Anomalies through Interactive Visualization

Directory of Open Access Journals (Sweden)

Tao Zhang

2014-06-01

Full Text Available As we move into the big data era, data grows not just in size, but also in complexity, containing a rich set of attributes, including location and time information, such as data from mobile devices (e.g., smart phones, natural disasters (e.g., earthquake and hurricane, epidemic spread, etc. We are motivated by the rising challenge and build a visualization tool for exploring generic spatiotemporal data, i.e., records containing time location information and numeric attribute values. Since the values often evolve over time and across geographic regions, we are particularly interested in detecting and analyzing the anomalous changes over time/space. Our analytic tool is based on geographic information system and is combined with spatiotemporal data mining algorithms, as well as various data visualization techniques, such as anomaly grids and anomaly bars superimposed on the map. We study how effective the tool may guide users to find potential anomalies through demonstrating and evaluating over publicly available spatiotemporal datasets. The tool for spatiotemporal anomaly analysis and visualization is useful in many domains, such as security investigation and monitoring, situation awareness, etc.

Congenital anomalies and proximity to landfill sites.

LENUS (Irish Health Repository)

Boyle, E

2004-01-01

The occurrence of congenital anomalies in proximity to municipal landfill sites in the Eastern Region (counties Dublin, Kildare, Wicklow) was examined by small area (district electoral division), distance and clustering tendancies in relation to 83 landfills, five of which were major sites. The study included 2136 cases of congenital anomaly, 37,487 births and 1423 controls between 1986 and 1990. For the more populous areas of the region 50% of the population lived within 2-3 km of a landfill and within 4-5 km for more rural areas. In the area-level analysis, the standardised prevalence ratios, empirical and full Bayesian modelling, and Kulldorff\\'s spatial scan statistic found no association between the residential area of cases and location of landfills. In the case control analysis, the mean distance of cases and controls from the nearest landfill was similar. The odds ratios of cases compared to controls for increasing distances from all landfills and major landfills showed no significant difference from the baseline value of 1. The kernel and K methods showed no tendency of cases to cluster in relationship to landfills. In conclusion, congenital anomalies were not found to occur more commonly in proximity to municipal landfills.

Anomaly-free models for flavour anomalies

Science.gov (United States)

Ellis, John; Fairbairn, Malcolm; Tunney, Patrick

2018-03-01

We explore the constraints imposed by the cancellation of triangle anomalies on models in which the flavour anomalies reported by LHCb and other experiments are due to an extra U(1)^' gauge boson Z^' . We assume universal and rational U(1)^' charges for the first two generations of left-handed quarks and of right-handed up-type quarks but allow different charges for their third-generation counterparts. If the right-handed charges vanish, cancellation of the triangle anomalies requires all the quark U(1)^' charges to vanish, if there are either no exotic fermions or there is only one Standard Model singlet dark matter (DM) fermion. There are non-trivial anomaly-free models with more than one such `dark' fermion, or with a single DM fermion if right-handed up-type quarks have non-zero U(1)^' charges. In some of the latter models the U(1)^' couplings of the first- and second-generation quarks all vanish, weakening the LHC Z^' constraint, and in some other models the DM particle has purely axial couplings, weakening the direct DM scattering constraint. We also consider models in which anomalies are cancelled via extra vector-like leptons, showing how the prospective LHC Z^' constraint may be weakened because the Z^' → μ ^+ μ ^- branching ratio is suppressed relative to other decay modes.

Carboxyl-terminal multi-site phosphorylation regulates internalization and desensitization of the human sst2 somatostatin receptor.

Science.gov (United States)

Lehmann, Andreas; Kliewer, Andrea; Schütz, Dagmar; Nagel, Falko; Stumm, Ralf; Schulz, Stefan

2014-04-25

The somatostatin receptor 2 (sst2) is the pharmacological target of somatostatin analogs that are widely used in the diagnosis and treatment of human neuroendocrine tumors. We have recently shown that the stable somatostatin analogs octreotide and pasireotide (SOM230) stimulate distinct patterns of sst2 receptor phosphorylation and internalization. Like somatostatin, octreotide promotes the phosphorylation of at least six carboxyl-terminal serine and threonine residues namely S341, S343, T353, T354, T356 and T359, which in turn leads to a robust receptor endocytosis. Unlike somatostatin, pasireotide stimulates a selective phosphorylation of S341 and S343 of the human sst2 receptor followed by a partial receptor internalization. Here, we show that exchange of S341 and S343 by alanine is sufficient to block pasireotide-driven internalization, whereas mutation of T353, T354, T356 and T359 to alanine is required to strongly inhibited both octreotide- and somatostatin-induced internalization. Yet, combined mutation of T353, T354, T356 and T359 is not sufficient to prevent somatostatin-driven β-arrestin mobilization and receptor desensitization. Replacement of all fourteen carboxyl-terminal serine and threonine residues by alanine completely abrogates sst2 receptor internalization and β-arrestin mobilization in HEK293 cells. Together, our findings demonstrate for the first time that agonist-selective sst2 receptor internalization is regulated by multi-site phosphorylation of its carboxyl-terminal tail. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Modelling the diurnal variability of SST and its vertical extent

DEFF Research Database (Denmark)

Karagali, Ioanna; Høyer, Jacob L.; Donlon, Craig J.

2014-01-01

of the water column where most of the heat is absorbed and where the exchange of heat and momentum with the atmosphere occurs. During day-time and under favourable conditions of low winds and high insolation, diurnal warming of the upper layer poses challenges for validating and calibrating satellite sensors......Sea Surface Temperature (SST) is a key variable in air-sea interactions, partly controlling the oceanic uptake of CO2 and the heat exchange between the ocean and the atmosphere, amongst others. Satellite SSTs are representative of skin and sub-skin temperature, i.e. in the upper millimetres...... and merging SST time series. When radiometer signals, typically from satellites, are validated with in situ measurements from drifting and moored buoys a general mismatch is found, associated with the different reference depth of each type of measurement. A generally preferred approach to bridge the gap...

SST, Aqua AMSR-E, 0.25 degrees, Global, Near Real Time

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NOAA OceanWatch provides sea surface temperature (SST) products derived from microwave sensors, which can measure ocean temperatures even in the presence of clouds....

Diversity in the representation of large-scale circulation associated with ENSO-Indian summer monsoon teleconnections in CMIP5 models

Science.gov (United States)

Ramu, Dandi A.; Chowdary, Jasti S.; Ramakrishna, S. S. V. S.; Kumar, O. S. R. U. B.

2018-04-01

Realistic simulation of large-scale circulation patterns associated with El Niño-Southern Oscillation (ENSO) is vital in coupled models in order to represent teleconnections to different regions of globe. The diversity in representing large-scale circulation patterns associated with ENSO-Indian summer monsoon (ISM) teleconnections in 23 Coupled Model Intercomparison Project Phase 5 (CMIP5) models is examined. CMIP5 models have been classified into three groups based on the correlation between Niño3.4 sea surface temperature (SST) index and ISM rainfall anomalies, models in group 1 (G1) overestimated El Niño-ISM teleconections and group 3 (G3) models underestimated it, whereas these teleconnections are better represented in group 2 (G2) models. Results show that in G1 models, El Niño-induced Tropical Indian Ocean (TIO) SST anomalies are not well represented. Anomalous low-level anticyclonic circulation anomalies over the southeastern TIO and western subtropical northwest Pacific (WSNP) cyclonic circulation are shifted too far west to 60° E and 120° E, respectively. This bias in circulation patterns implies dry wind advection from extratropics/midlatitudes to Indian subcontinent. In addition to this, large-scale upper level convergence together with lower level divergence over ISM region corresponding to El Niño are stronger in G1 models than in observations. Thus, unrealistic shift in low-level circulation centers corroborated by upper level circulation changes are responsible for overestimation of ENSO-ISM teleconnections in G1 models. Warm Pacific SST anomalies associated with El Niño are shifted too far west in many G3 models unlike in the observations. Further large-scale circulation anomalies over the Pacific and ISM region are misrepresented during El Niño years in G3 models. Too strong upper-level convergence away from Indian subcontinent and too weak WSNP cyclonic circulation are prominent in most of G3 models in which ENSO-ISM teleconnections are

Comparative assessment of seller's staining test (SST) and direct ...

African Journals Online (AJOL)

the only standard method. Objective: This study was designed to assess the sensitivity and specificity of the SST in relation to the 'gold standard' dFAT in diagnosis of rabies in Nigeria. Methods: A total of 88 animal specimens submitted to the Rabies National Reference Laboratory, Nigeria were routinely tested for rabies by ...

Baking and helium glow discharge cleaning of SST-1 tokamak with graphite plasma facing components

International Nuclear Information System (INIS)

Semwal, Pratibha; Khan, Ziauddin; Raval, Dilip

2015-01-01

Graphite plasma facing components (PFCs) were installed inside SST-1 vacuum vessel. Prior to installation, all the graphite tiles were baked at 1000 °C in a vacuum furnace operated below 1.0 X 10 -5 mbar. However due to the porous structure of graphite, they absorb a significant amount of water vapour from air during the installation process. Rapid desorption of water vapour requires high temperature bake-out of the PFCs at ≥ 250 °C. In SST-1 the PFCs were baked at 250 °C using hot nitrogen gas facility to remove the absorbed water vapour. Also device with large graphite surface area has the disadvantage that a large quantity of hydrogen gets trapped inside it during plasma discharges which makes density control difficult. Helium (He) glow discharge cleaning (GDC) effectively removes this stored hydrogen as well as other impurities like oxygen and hydrocarbon within few nanometers from the surface by particle induced desorption. Before plasma operation in SST-1 tokamak, both baking of PFCs and He-GDC were carried out so that these impurities were removed effectively. The mean desorption yield of hydrogen was found to be 0.48. In this paper, the results of effect of baking and He-GDC experiments of SST-1 will be presented in detail. (author)

Baking and helium glow discharge cleaning of SST-1 Tokamak with graphite plasma facing components

Science.gov (United States)

Semwal, P.; Khan, Z.; Raval, D. C.; Dhanani, K. R.; George, S.; Paravastu, Y.; Prakash, A.; Thankey, P.; Ramesh, G.; Khan, M. S.; Saikia, P.; Pradhan, S.

2017-04-01

Graphite plasma facing components (PFCs) were installed inside the SST-1 vacuum vessel. Prior to installation, all the graphite tiles were baked at 1000 °C in a vacuum furnace operated below 1.0 × 10-5 mbar. However due to the porous structure of graphite, they absorb a significant amount of water vapour from air during the installation process. Rapid desorption of this water vapour requires high temperature bake-out of the PFCs at ≥ 250 °C. In SST-1 the PFCs were baked at 250 °C using hot nitrogen gas facility to remove the absorbed water vapour. Also device with large graphite surface area has the disadvantage that a large quantity of hydrogen gets trapped inside it during plasma discharges which makes density control difficult. Helium glow discharge cleaning (He-GDC) effectively removes this stored hydrogen as well as other impurities like oxygen and hydrocarbon within few nano-meters from the surface by particle induced desorption. Before plasma operation in SST-1 tokamak, both baking of PFCs and He-GDC were carried out so that these impurities were removed effectively. The mean desorption yield of hydrogen was found to be 0.24. In this paper the results of baking and He-GDC experiments of SST-1 will be presented in detail.

Genome-Scale Analysis Reveals Sst2 as the Principal Regulator of Mating Pheromone Signaling in the Yeast Saccharomyces cerevisiae†

Science.gov (United States)

Chasse, Scott A.; Flanary, Paul; Parnell, Stephen C.; Hao, Nan; Cha, Jiyoung Y.; Siderovski, David P.; Dohlman, Henrik G.

2006-01-01

A common property of G protein-coupled receptors is that they become less responsive with prolonged stimulation. Regulators of G protein signaling (RGS proteins) are well known to accelerate G protein GTPase activity and do so by stabilizing the transition state conformation of the G protein α subunit. In the yeast Saccharomyces cerevisiae there are four RGS-homologous proteins (Sst2, Rgs2, Rax1, and Mdm1) and two Gα proteins (Gpa1 and Gpa2). We show that Sst2 is the only RGS protein that binds selectively to the transition state conformation of Gpa1. The other RGS proteins also bind Gpa1 and modulate pheromone signaling, but to a lesser extent and in a manner clearly distinct from Sst2. To identify other candidate pathway regulators, we compared pheromone responses in 4,349 gene deletion mutants representing nearly all nonessential genes in yeast. A number of mutants produced an increase (sst2, bar1, asc1, and ygl024w) or decrease (cla4) in pheromone sensitivity or resulted in pheromone-independent signaling (sst2, pbs2, gas1, and ygl024w). These findings suggest that Sst2 is the principal regulator of Gpa1-mediated signaling in vivo but that other proteins also contribute in distinct ways to pathway regulation. PMID:16467474

Seafloor spreading anomalies and crustal ages of the Clarion-Clipperton Zone

OpenAIRE

Udo Barckhausen; Meike Bagge; Douglas S. Wilson

2013-01-01

The Clarion-Clipperton Zone (CCZ) of the central Pacific is one of the few regions in the world’s oceans that are still lacking full coverage of reliable identifications of seafloor spreading anomalies. This is mainly due to the geometry of the magnetic lineations’ strike direction sub-parallel to the Earth’s magnetic field vector near the equator resulting in low amplitude magnetic anomalies, and the remoteness of the region which has hindered systematic surveying in the past. Following rece...

The high-resolution global SST forecast set of the CSIR

CSIR Research Space (South Africa)

Landman, WA

2011-09-01

Full Text Available -RESOLUTION GLOBAL SST FORECAST SET OF THE CSIR Willem A. Landman Council for Scientific and Industrial Research, P. O. Box 395, Pretoria, 0001, South Africa David G. DeWitt and Dong-Eun Lee International Research Institute for Climate and Society, Lamont...

Cool Down Experiences with the SST-1 Helium Cryogenics System before and after Current Feeders System Modification

Science.gov (United States)

Patel, R.; Panchal, P.; Panchal, R.; Tank, J.; Mahesuriya, G.; Sonara, D.; Srikanth, G. L. N.; Garg, A.; Bairagi, N.; Christian, D.; Patel, K.; Shah, P.; Nimavat, H.; Sharma, R.; Patel, J. C.; Gupta, N. C.; Prasad, U.; Sharma, A. N.; Tanna, V. L.; Pradhan, S.

The SST-1 machine comprises a superconducting magnet system (SCMS), which includes TF and PF magnets. In order to charge the SCMS, we need superconducting current feeders consisting of SC feeders and vapor cooled current leads (VCCLs). We have installed all 10 (+/-) pairs of VCCLs for the TF and PF systems. While conducting initial engineering validation of the SST-1 machine, our prime objective was to produce circular plasma using only the TF system. During the SST-1 campaign I to VI, we have to stop the PF magnets cooling in order to get the cryo- stable conditions for current charging of the TF magnets system. In that case, the cooling of the PF current leads is not essential. It has been also observed that after aborting the PF system cooling, there was a limited experimental window of TF operation. Therefore, in the recent SST-1 campaign-VII, we removed the PF current leads (9 pairs) and kept only single (+/-) pair of the 10,000 A rated VCCLs to realize the charging of the TF system for the extended window of operation. We have observed a better cryogenic stability in the TF magnets after modifications in the CFS. In this paper, we report the comparison of the cool down performance for the SST-1 machine operation before and after modifications of the current feeders system.

North-East monsoon rainfall extremes over the southern peninsular India and their association with El Niño

Science.gov (United States)

Singh, Prem; Gnanaseelan, C.; Chowdary, J. S.

2017-12-01

The present study investigates the relationship between extreme north-east (NE) monsoon rainfall (NEMR) over the Indian peninsula region and El Niño forcing. This turns out to be a critical science issue especially after the 2015 Chennai flood. The puzzle being while most El Niños favour good NE monsoon, some don't. In fact some El Niño years witnessed deficit NE monsoon. Therefore two different cases (or classes) of El Niños are considered for analysis based on standardized NEMR index and Niño 3.4 index with case-1 being both Niño-3.4 and NEMR indices greater than +1 and case-2 being Niño-3.4 index greater than +1 and NEMR index less than -1. Composite analysis suggests that SST anomalies in the central and eastern Pacific are strong in both cases but large differences are noted in the spatial distribution of SST over the Indo-western Pacific region. This questions our understanding of NEMR as mirror image of El Niño conditions in the Pacific. It is noted that the favourable excess NEMR in case-1 is due to anomalous moisture transport from Bay of Bengal and equatorial Indian Ocean to southern peninsular India. Strong SST gradient between warm western Indian Ocean (and Bay of Bengal) and cool western Pacific induced strong easterly wind anomalies during NE monsoon season favour moisture transport towards the core NE monsoon region. Further anomalous moisture convergence and convection over the core NE monsoon region supported positive rainfall anomalies in case-1. While in case-2, weak SST gradients over the Indo-western Pacific and absence of local low level convergence over NE monsoon region are mainly responsible for deficit rainfall. The ocean dynamics in the Indian Ocean displayed large differences during case-1 and case-2, suggesting the key role of Rossby wave dynamics in the Indian Ocean on NE monsoon extremes. Apart from the large scale circulation differences the number of cyclonic systems land fall for case-1 and case-2 have also contributed for

Clinical evaluation of nonsyndromic dental anomalies in Dravidian population: A cluster sample analysis.

Science.gov (United States)

Yamunadevi, Andamuthu; Selvamani, M; Vinitha, V; Srivandhana, R; Balakrithiga, M; Prabhu, S; Ganapathy, N

2015-08-01

To record the prevalence rate of dental anomalies in Dravidian population and analyze the percentage of individual anomalies in the population. A cluster sample analysis was done, where 244 subjects studying in a dental institution were all included and analyzed for occurrence of dental anomalies by clinical examination, excluding third molars from analysis. 31.55% of the study subjects had dental anomalies and shape anomalies were more prevalent (22.1%), followed by size (8.6%), number (3.2%) and position anomalies (0.4%). Retained deciduous was seen in 1.63%. Among the individual anomalies, Talon's cusp (TC) was seen predominantly (14.34%), followed by microdontia (6.6%) and supernumerary cusps (5.73%). Prevalence rate of dental anomalies in the Dravidian population is 31.55% in the present study, exclusive of third molars. Shape anomalies are more common, and TC is the most commonly noted anomaly. Varying prevalence rate is reported in different geographical regions of the world.

The prognostic value of sST2 and galectin-3 considering different aetiologies in non-ischaemic heart failure.

Science.gov (United States)

Binas, David; Daniel, Hanna; Richter, Anette; Ruppert, Volker; Schlüter, Klaus-Dieter; Schieffer, Bernhard; Pankuweit, Sabine

2018-01-01

Several studies indicate a prognostic value of sST2 and galectin-3 in heart failure (HF). While previous studies focused on ischaemic cause of HF, we investigated the role of sST2 and galectin-3 in patients with non-ischaemic dilated cardiomyopathy (DCM). sST2 and galectin-3 serum concentrations were measured in 262 subjects with DCM. Survival rates were determined for all-cause mortality (ACM) and cardiac mortality (CM). In a univariate model, sST2 as a continuous variable was a predictor of ACM (HR 1.05; 95% CI 1.03 to 1.07, PACM (HR 1.10; 95% CI 1.05 to 1.17, PACM (HR 1.04; 95% CI 1.01 to 1.07, P=0.019) was significant. In a multivariate model, the prognostic value of the sST2 main group remained intact for ACM (HR 1.04; 95% CI 1.02 to 1.07, P=0.003).Univariate and multivariate analysis of galectin-3 as continuous variable did not show any significant result. However, in a quartile model, intermediate values of galectin-3 were significantly associated with a lower event rate of ACM and CM. The study revealed that sST2 predicts ACM and CM in patients with non-ischaemic HF and could be useful especially in patients with inflammatory background. Our findings that intermediate levels of galectin-3 allow for better prognosis were new and different to other investigations. NCT03090425; Results.

PXIe based data acquisition and control system for ECRH systems on SST-1 and Aditya tokamak

Energy Technology Data Exchange (ETDEWEB)

Patel, Jatinkumar J., E-mail: jatin@ipr.res.in [Institute for Plasma Research, Bhat, Gandhinagar (India); Shukla, B.K.; Rajanbabu, N.; Patel, H.; Dhorajiya, P.; Purohit, D. [Institute for Plasma Research, Bhat, Gandhinagar (India); Mankadiya, K. [Optimized Solutions Pvt. Ltd (India)

2016-11-15

Highlights: • Data Aquisition and control system (DAQ). • PXIe hardware–(PXI–PCI bus extension for Instrumention Express). • RHVPS–Regulated High Voltage Power supply. • SST1–Steady state superconducting tokamak. - Abstract: In Steady State Superconducting (SST-1) tokamak, various RF heating sub-systems are used for plasma heating experiments. In SST-1, Two Electron Cyclotron Resonance Heating (ECRH) systems have been installed for pre-ionization, heating and current drive experiments. The 42 GHz gyrotron based ECRH system is installed and in operation with SST-1 plasma experiments. The 82.6 GHz gyrotron delivers 200 kW CW power (1000 s) while the 42 GHz gyrotron delivers 500 kW power for 500 ms duration. Each gyrotron system consists of various auxiliary power supplies, the crowbar unit and the water cooling system. The PXIe (PCI bus extension for Instrumentation Express)bus based DAC (Data Acquisition and Control) system has been designed, developed and under implementation for safe and reliable operation of the gyrotron. The Control and Monitoring Software applications have been developed using NI LabView 2014 software with real time support on windows platform.

PXIe based data acquisition and control system for ECRH systems on SST-1 and Aditya tokamak

International Nuclear Information System (INIS)

Patel, Jatinkumar J.; Shukla, B.K.; Rajanbabu, N.; Patel, H.; Dhorajiya, P.; Purohit, D.; Mankadiya, K.

2016-01-01

Highlights: • Data Aquisition and control system (DAQ). • PXIe hardware–(PXI–PCI bus extension for Instrumention Express). • RHVPS–Regulated High Voltage Power supply. • SST1–Steady state superconducting tokamak. - Abstract: In Steady State Superconducting (SST-1) tokamak, various RF heating sub-systems are used for plasma heating experiments. In SST-1, Two Electron Cyclotron Resonance Heating (ECRH) systems have been installed for pre-ionization, heating and current drive experiments. The 42 GHz gyrotron based ECRH system is installed and in operation with SST-1 plasma experiments. The 82.6 GHz gyrotron delivers 200 kW CW power (1000 s) while the 42 GHz gyrotron delivers 500 kW power for 500 ms duration. Each gyrotron system consists of various auxiliary power supplies, the crowbar unit and the water cooling system. The PXIe (PCI bus extension for Instrumentation Express)bus based DAC (Data Acquisition and Control) system has been designed, developed and under implementation for safe and reliable operation of the gyrotron. The Control and Monitoring Software applications have been developed using NI LabView 2014 software with real time support on windows platform.

Daily SST fields produced by blending infrared and microwave radiometer estimates

Digital Repository Service at National Institute of Oceanography (India)

Sreejith, O.P.; Shenoi, S.S.C.

Measurement of Sea Surface Temperature (SST) using satellite based sensors have matured during the last decade. The infrared measurements, using the AVHRR sensor, flown onboard the NOAA satellites, have been used for the generation of high...

Manifestation of two meddies in altimetry and sea-surface temperature

Directory of Open Access Journals (Sweden)

I. Bashmachnikov

2013-03-01

Full Text Available Two meddies were identified in the Iberian Basin using shipboard ADCP (Meddy 1 and Argo float (Meddy 2 in contrasting background conditions. Meddy 1 was observed while interacting with the Azores Current (AzC, while Meddy 2 was observed in a much calmer dynamical background, north from the AzC jet. In both cases the meddies formed a clear anticyclonic surface signal, detectable in altimetry as well as in sea-surface temperature (SST. Analysis of the in situ observations of the dynamic signal over Meddy 1 showed that the signal, generated by the moving meddy, dominated the AzC dynamics at least up to the base of the seasonal thermocline even at the late stages of its interaction with the jet. The centre of rotation of the surface signal was shifted south-westward from the axis of the meddy by about 18 km, and its dynamic radius was 2 times bigger than that of the meddy. In the centre of the anticyclonic surface signals of both meddies, SST was colder than that of the surrounding water, in contrast to warm SST anomalies in the cores of surface anticyclones generated by meandering surface currents. The latter difference gives ground for identification of meddies (as well as other sub-surface anticyclones in comparatively dynamically calm regions using coupled altimetry–SST remote sensing data. An identification of Meddy 1 prior to the shipboard ADCP measurements was the first successful experience. At the same time, SST anomalies over the meddies were rather weak, often unstable and statistically significant only over periods of months.

Analysis of pre-earthquake ionospheric anomalies before the global M = 7.0+ earthquakes in 2010

Directory of Open Access Journals (Sweden)

W. F. Peng

2012-03-01

Full Text Available The pre-earthquake ionospheric anomalies that occurred before the global M = 7.0+ earthquakes in 2010 are investigated using the total electron content (TEC from the global ionosphere map (GIM. We analyze the possible causes of the ionospheric anomalies based on the space environment and magnetic field status. Results show that some anomalies are related to the earthquakes. By analyzing the time of occurrence, duration, and spatial distribution of these ionospheric anomalies, a number of new conclusions are drawn, as follows: earthquake-related ionospheric anomalies are not bound to appear; both positive and negative anomalies are likely to occur; and the earthquake-related ionospheric anomalies discussed in the current study occurred 0–2 days before the associated earthquakes and in the afternoon to sunset (i.e. between 12:00 and 20:00 local time. Pre-earthquake ionospheric anomalies occur mainly in areas near the epicenter. However, the maximum affected area in the ionosphere does not coincide with the vertical projection of the epicenter of the subsequent earthquake. The directions deviating from the epicenters do not follow a fixed rule. The corresponding ionospheric effects can also be observed in the magnetically conjugated region. However, the probability of the anomalies appearance and extent of the anomalies in the magnetically conjugated region are smaller than the anomalies near the epicenter. Deep-focus earthquakes may also exhibit very significant pre-earthquake ionospheric anomalies.

Kaplan Extended V2 SST anomaly data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Data is processed at Lamont-Doherty using a optimal analysis scheme. This dataset is different than previously archived version from Nov 1981 due to a different NCEP...

Predictive value of serum sST2 in preschool wheezers for development of asthma with high FeNO.

Science.gov (United States)

Ketelaar, M E; van de Kant, K D; Dijk, F N; Klaassen, E M; Grotenboer, N S; Nawijn, M C; Dompeling, E; Koppelman, G H

2017-11-01

Wheezing is common in childhood. However, current prediction models of pediatric asthma have only modest accuracy. Novel biomarkers and definition of subphenotypes may improve asthma prediction. Interleukin-1-receptor-like-1 (IL1RL1 or ST2) is a well-replicated asthma gene and associates with eosinophilia. We investigated whether serum sST2 predicts asthma and asthma with elevated exhaled NO (FeNO), compared to the commonly used Asthma Prediction Index (API). Using logistic regression modeling, we found that serum sST2 levels in 2-3 years-old wheezers do not predict doctors' diagnosed asthma at age 6 years. Instead, sST2 predicts a subphenotype of asthma characterized by increased levels of FeNO, a marker for eosinophilic airway inflammation. Herein, sST2 improved the predictive value of the API (AUC=0.70, 95% CI 0.56-0.84), but had also significant predictive value on its own (AUC=0.65, 95% CI 0.52-0.79). Our study indicates that sST2 in preschool wheezers has predictive value for the development of eosinophilic airway inflammation in asthmatic children at school age. © 2017 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.

Characteristics and Mechanisms of Zonal Oscillation of Western Pacific Subtropical High in Summer

Science.gov (United States)

Guan, W.; Ren, X.; Hu, H.

2017-12-01

The zonal oscillation of the western Pacific subtropical high (WPSH) influences the weather and climate over East Asia significantly. This study investigates the features and mechanisms of the zonal oscillation of the WPSH during summer on subseasonal time scales. The zonal oscillation index of the WPSH is defined by normalized subseasonal geopotential height anomaly at 500hPa averaged over the WPSH's western edge (110° - 140°E, 10° - 30°N). The index shows a predominant oscillation with a period of 10-40 days. Large positive index indicates a strong anticyclonic anomaly over East Asia and its coastal region south of 30°N at both 850hPa and 500hPa. The WPSH stretches more westward accompanied by warmer SST anomalies beneath the western edge of the WPSH. Meanwhile, above-normal precipitation is seen over the Yangtze-Huaihe river basin and below-normal precipitation over the south of the Yangtze River. Negative index suggests a more eastward position of WPSH. The anomalies in circulation and SST for negative index are almost the mirror image of those for the positive index. In early summer, the zonal shift of the WPSH is affected by both the East Asia/Pacific (EAP) teleconnection pattern and the Silk road pattern (SRP). The positive (negative) phase of the EAP pattern is characterized by a low-level anticyclonic (cyclonic) anomaly over the subtropical western Pacific, indicating the western extension (eastward retreat) of the WPSH. Comparing with the EAP pattern, the SRP forms an upper-level anticyclonic (cyclonic) anomaly in mid-latitudes of East Asia, and then leads to the westward (eastward) movement of the WPSH. In late summer, the zonal shift of the WPSH is mainly affected by the EAP pattern, because the EAP pattern in late summer is stronger than that in early summer. The zonal shift of the WPSH is also influenced by the subseasonal air-sea interaction locally. During the early stage of WPSH's westward stretch, the local SST anomaly in late summer is

A possible cause of the AO polarity reversal from winter to summer in 2010 and its relation to hemispheric extreme hot summer

Science.gov (United States)

Tachibana, Yoshihiro; Otomi, Yuriko; Nakamura, Tetsu

2013-04-01

In 2010, the Northern Hemisphere, in particular Russia and Japan, experienced an abnormally hot summer characterized by record-breaking warm temperatures and associated with a strongly positive Arctic Oscillation (AO), that is, low pressure in the Arctic and high pressure in the midlatitudes. In contrast, the AO index the previous winter and spring (2009/2010) was record-breaking negative. The AO polarity reversal that began in summer 2010 can explain the abnormally hot summer. The winter sea surface temperatures (SST) in the North Atlantic Ocean showed a tripolar anomaly pattern—warm SST anomalies over the tropics and high latitudes and cold SST anomalies over the midlatitudes—under the influence of the negative AO. The warm SST anomalies continued into summer 2010 because of the large oceanic heat capacity. A model simulation strongly suggested that the AO-related summertime North Atlantic oceanic warm temperature anomalies remotely caused blocking highs to form over Europe, which amplified the positive summertime AO. Thus, a possible cause of the AO polarity reversal might be the "memory" of the negative winter AO in the North Atlantic Ocean, suggesting an interseasonal linkage of the AO in which the oceanic memory of a wintertime negative AO induces a positive AO in the following summer. Understanding of this interseasonal linkage may aid in the long-term prediction of such abnormal summer events.

A possible cause of the AO polarity reversal from winter to summer in 2010 and its relation to hemispheric extreme summer weather

Science.gov (United States)

Otomi, Yuriko; Tachibana, Yoshihiro; Nakamura, Tetsu

2013-04-01

In 2010, the Northern Hemisphere, in particular Russia and Japan, experienced an abnormally hot summer characterized by record-breaking warm temperatures and associated with a strongly positive Arctic Oscillation (AO), that is, low pressure in the Arctic and high pressure in the midlatitudes. In contrast, the AO index the previous winter and spring (2009/2010) was record-breaking negative. The AO polarity reversal that began in summer 2010 can explain the abnormally hot summer. The winter sea surface temperatures (SST) in the North Atlantic Ocean showed a tripolar anomaly pattern—warm SST anomalies over the tropics and high latitudes and cold SST anomalies over the midlatitudes—under the influence of the negative AO. The warm SST anomalies continued into summer 2010 because of the large oceanic heat capacity. A model simulation strongly suggested that the AO-related summertime North Atlantic oceanic warm temperature anomalies remotely caused blocking highs to form over Europe, which amplified the positive summertime AO. Thus, a possible cause of the AO polarity reversal might be the "memory" of the negative winter AO in the North Atlantic Ocean, suggesting an interseasonal linkage of the AO in which the oceanic memory of a wintertime negative AO induces a positive AO in the following summer. Understanding of this interseasonal linkage may aid in the long-term prediction of such abnormal summer events.

Rarotonga Sr/Ca and SST Reconstruction Data for 1726 to 1997

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A 271 year record of Sr/Ca variability in a coral from Rarotonga in the South Pacific gyre. Calibration with monthly sea surface temperature (SST) from satellite and...

Interannual Variations in the Synoptic-Scale Disturbances over the western North Pacific

Science.gov (United States)

Zhou, Xingyan; Lu, Riyu

2017-04-01

The present study investigates the interannual variation of synoptic disturbance activities over the western North Pacific (WNP) and its relationship with the large-scale circulation and tropical SST during June-November for the period 1958-2014. It is shown that the interannual variability of 850-hPa eddy kinetic energy (EKE) anomalies over the WNP could be well described by its two leading modes of EOF, i.e., northeast pattern and southwest pattern. The high value zone of former is located over the WNP, while latter around the Philippines, which just overlap a broad area of the WNP. Background flows play an important role in the formation of these two patterns, it could induce the cyclonic ( anticyclonic ) anomalies over the variation centers which favors ( disfavors) synoptic eddies to get kinetic energy from the mean flows through barotropic energy conversion. The SST anomalies of the equatorial central and eastern Pacific also contribute to these two patterns. When the SST of equatorial central and eastern Pacific above (below) the normal, a cyclonic (anticyclonic) anomaly appears in the Philippine Sea while an anticyclonic (cyclonic) anomaly happens in the South China Sea, which will induce positive (negative) EKE anomalies over the WNP but negative (positive) anomalies over the South China Sea and the Philippines.

CORBA-based solution for remote participation in SST-1 tokamak control and operation

Energy Technology Data Exchange (ETDEWEB)

Mahajan, Kirti [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382428 (India)]. E-mail: kirti@ipr.res.in; Ravikiran, M. [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382428 (India); Gulati, Hitesh [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382428 (India); Dave, H.J. [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382428 (India); Kumar, Neeraj [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382428 (India); Patel, Kirit [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382428 (India); Kumar, Aveg [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382428 (India); Raju, D. [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382428 (India); Bhandarkar, M. [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382428 (India); Chudasama, H. [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382428 (India); Kulkarni, S.V. [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382428 (India); Saxena, Y.C. [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382428 (India)

2006-07-15

The steady state superconducting tokamak (SST-1) central control system is a distributed heterogeneous process communication system built on socket programming. It consists of machine, experiment and discharge control plus timing and a database. The software controls and monitors SST-1 subsystems: water-cooling, power supplies, cryogenics and vacuum over a local area network (LAN). The SST-1 control room is the place where all the activities like session announcement, machine control, experiment control, discharge control and monitoring are performed. We have realized that, instead of having a single monitoring place, we should have multiple monitoring points and it should be made possible to control the experiment from any PC over the LAN. In order to meet such requirements for remote participation in tokamak operation, we are upgrading the existing software. The upgraded software is based on Common Object Request Broker Architecture (CORBA) technology. The software is utilizing CORBA-services such as event service, naming services, interface repository and security services. The inherent features of CORBA make the software, platform and language independent. The software supports a variety of communication paradigms including publish-subscribe, peer-to-peer, and request-reply. Based on this software, one can participate in SST-1 tokamak operation from the LAN, or a wide area network (WAN) connection anywhere on the Internet. Each user can customize plasma parameters and diagnostics data that he wants to monitor, at any time without any change in the software and a copy of these parameters will be available to him. This paper focuses on the publish-subscribe communication paradigm and its application for a machine monitoring system.

CORBA-based solution for remote participation in SST-1 tokamak control and operation

International Nuclear Information System (INIS)

Mahajan, Kirti; Ravikiran, M.; Gulati, Hitesh; Dave, H.J.; Kumar, Neeraj; Patel, Kirit; Kumar, Aveg; Raju, D.; Bhandarkar, M.; Chudasama, H.; Kulkarni, S.V.; Saxena, Y.C.

2006-01-01

The steady state superconducting tokamak (SST-1) central control system is a distributed heterogeneous process communication system built on socket programming. It consists of machine, experiment and discharge control plus timing and a database. The software controls and monitors SST-1 subsystems: water-cooling, power supplies, cryogenics and vacuum over a local area network (LAN). The SST-1 control room is the place where all the activities like session announcement, machine control, experiment control, discharge control and monitoring are performed. We have realized that, instead of having a single monitoring place, we should have multiple monitoring points and it should be made possible to control the experiment from any PC over the LAN. In order to meet such requirements for remote participation in tokamak operation, we are upgrading the existing software. The upgraded software is based on Common Object Request Broker Architecture (CORBA) technology. The software is utilizing CORBA-services such as event service, naming services, interface repository and security services. The inherent features of CORBA make the software, platform and language independent. The software supports a variety of communication paradigms including publish-subscribe, peer-to-peer, and request-reply. Based on this software, one can participate in SST-1 tokamak operation from the LAN, or a wide area network (WAN) connection anywhere on the Internet. Each user can customize plasma parameters and diagnostics data that he wants to monitor, at any time without any change in the software and a copy of these parameters will be available to him. This paper focuses on the publish-subscribe communication paradigm and its application for a machine monitoring system

GHRSST Level 2P USA NAVOCEANO AVHRR METOP-A Global SST:1

Data.gov (United States)

National Aeronautics and Space Administration — Multi-Channel SST retreivals generated in real-time from METOP-A AVHRR Global Area Coverage data. Used operationally in Navy oceanographic analyses and forecasts.

Baking and helium glow discharge cleaning of SST-1 Tokamak with graphite plasma facing components

International Nuclear Information System (INIS)

Semwal, P; Khan, Z; Raval, D C; Dhanani, K R; George, S; Paravastu, Y; Prakash, A; Thankey, P; Ramesh, G; Khan, M S; Saikia, P; Pradhan, S

2017-01-01

Graphite plasma facing components (PFCs) were installed inside the SST-1 vacuum vessel. Prior to installation, all the graphite tiles were baked at 1000 °C in a vacuum furnace operated below 1.0 × 10 -5 mbar. However due to the porous structure of graphite, they absorb a significant amount of water vapour from air during the installation process. Rapid desorption of this water vapour requires high temperature bake-out of the PFCs at ≥ 250 °C. In SST-1 the PFCs were baked at 250 °C using hot nitrogen gas facility to remove the absorbed water vapour. Also device with large graphite surface area has the disadvantage that a large quantity of hydrogen gets trapped inside it during plasma discharges which makes density control difficult. Helium glow discharge cleaning (He-GDC) effectively removes this stored hydrogen as well as other impurities like oxygen and hydrocarbon within few nano-meters from the surface by particle induced desorption. Before plasma operation in SST-1 tokamak, both baking of PFCs and He-GDC were carried out so that these impurities were removed effectively. The mean desorption yield of hydrogen was found to be 0.24. In this paper the results of baking and He-GDC experiments of SST-1 will be presented in detail. (paper)