WorldWideScience

Sample records for surface ocean ph

  1. Characterisation and deployment of an immobilised pH sensor spot towards surface ocean pH measurements.

    Science.gov (United States)

    Clarke, Jennifer S; Achterberg, Eric P; Rérolle, Victoire M C; Abi Kaed Bey, Samer; Floquet, Cedric F A; Mowlem, Matthew C

    2015-10-15

    The oceans are a major sink for anthropogenic atmospheric carbon dioxide, and the uptake causes changes to the marine carbonate system and has wide ranging effects on flora and fauna. It is crucial to develop analytical systems that allow us to follow the increase in oceanic pCO2 and corresponding reduction in pH. Miniaturised sensor systems using immobilised fluorescence indicator spots are attractive for this purpose because of their simple design and low power requirements. The technology is increasingly used for oceanic dissolved oxygen measurements. We present a detailed method on the use of immobilised fluorescence indicator spots to determine pH in ocean waters across the pH range 7.6-8.2. We characterised temperature (-0.046 pH/°C from 5 to 25 °C) and salinity dependences (-0.01 pH/psu over 5-35), and performed a preliminary investigation into the influence of chlorophyll on the pH measurement. The apparent pKa of the sensor spots was 6.93 at 20 °C. A drift of 0.00014 R (ca. 0.0004 pH, at 25 °C, salinity 35) was observed over a 3 day period in a laboratory based drift experiment. We achieved a precision of 0.0074 pH units, and observed a drift of 0.06 pH units during a test deployment of 5 week duration in the Southern Ocean as an underway surface ocean sensor, which was corrected for using certified reference materials. The temperature and salinity dependences were accounted for with the algorithm, R=0.00034-0.17·pH+0.15·S(2)+0.0067·T-0.0084·S·1.075. This study provides a first step towards a pH optode system suitable for autonomous deployment. The use of a short duration low power illumination (LED current 0.2 mA, 5 μs illumination time) improved the lifetime and precision of the spot. Further improvements to the pH indicator spot operations include regular application of certified reference materials for drift correction and cross-calibration against a spectrophotometric pH system. Desirable future developments should involve novel

  2. Geoengineering impact of open ocean dissolution of olivine on atmospheric CO2, surface ocean pH and marine biology

    International Nuclear Information System (INIS)

    Köhler, Peter; Abrams, Jesse F; Völker, Christoph; Hauck, Judith; Wolf-Gladrow, Dieter A

    2013-01-01

    Ongoing global warming induced by anthropogenic emissions has opened the debate as to whether geoengineering is a ‘quick fix’ option. Here we analyse the intended and unintended effects of one specific geoengineering approach, which is enhanced weathering via the open ocean dissolution of the silicate-containing mineral olivine. This approach would not only reduce atmospheric CO 2 and oppose surface ocean acidification, but would also impact on marine biology. If dissolved in the surface ocean, olivine sequesters 0.28 g carbon per g of olivine dissolved, similar to land-based enhanced weathering. Silicic acid input, a byproduct of the olivine dissolution, alters marine biology because silicate is in certain areas the limiting nutrient for diatoms. As a consequence, our model predicts a shift in phytoplankton species composition towards diatoms, altering the biological carbon pumps. Enhanced olivine dissolution, both on land and in the ocean, therefore needs to be considered as ocean fertilization. From dissolution kinetics we calculate that only olivine particles with a grain size of the order of 1 μm sink slowly enough to enable a nearly complete dissolution. The energy consumption for grinding to this small size might reduce the carbon sequestration efficiency by ∼30%. (letter)

  3. Dissolved inorganic carbon, pH, oxygen, and other variables collected from surface discrete and surface underway observations using flow-through pump from NOAA Ship Gordon Gunter off the U.S. East Coast during the East Coast Ocean Acidification (ECOA) Cruise from 2015-06-19 to 2015-07-24 (NCEI Accession 0157485)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains dissolved inorganic carbon, pH, oxygen, and other variables collected from surface discrete and surface underway observations during...

  4. Dissolved inorganic carbon, total alkalinity, pH, and other variables collected from surface discrete observations using flow through pump and other instruments from Explorer of the Seas (ID: 33KF) in the Caribbean Sea and North Atlantic ocean during the Ocean Acidification Cruise EX1507 from 2015-02-14 to 2015-02-15 (NCEI Accession 0154385)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains surface discrete measurements of dissolved inorganic carbon, total alkalinity, pH in the Caribbean Sea. Increasing amounts of...

  5. Climatological Distributions of pH, pCO2, Total CO2, Alkalinity, and CaCO3 Saturation in the Global Surface Ocean (NCEI accession 01645680) (NCEI Accession 0164568)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Climatological mean monthly distributions of pH in the total H+ scale, total CO2 concentration (TCO2), and the degree of CaCO3 saturation for the global surface...

  6. OW CCMP Ocean Surface Wind

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Cross-Calibrated Multi-Platform (CCMP) Ocean Surface Wind Vector Analyses (Atlas et al., 2011) provide a consistent, gap-free long-term time-series of monthly...

  7. OW ASCAT Ocean Surface Winds

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Advanced Scatterometer (ASCAT) sensor onboard the EUMETSAT MetOp polar-orbiting satellite provides ocean surface wind observations by means of radar...

  8. Dissolved inorganic carbon, total alkalinity, pH, and other variables collected from surface and discrete observations using flow-through pump and other instruments from M/V Equinox in the North Atlantic ocean (east coast of Miami, FL, Bahamas, and Turks and Caicos Islands) from 2015-03-07 to 2015-03-09 (NCEI Accession 0154382)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains surface discrete measurements of dissolved inorganic carbon, total alkalinity, and pH from the east coast of Florida to Puerto Rico....

  9. Dissolved inorganic carbon, total alkalinity, pH, nutrients and other variables collected from surface discrete sampling using flow through pump and other instruments from NOAA Ship Gordon Gunter in the U.S. East Coast during the East Coast Ocean Acidification (GU-15-04 ECOA1) from 2015-06-20 to 2015-07-23 (NCEI Accession 0157389)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains dissolved inorganic carbon, total alkalinity, pH, nutrients and other variables collected from surface discrete sampling using flow...

  10. Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, pH, temperature, salinity and SEA SURFACE TEMPERATURE collected from Surface underway observations using automated Multi-parameter Inorganic Carbon Analyzer (MICA) for autonomous measurement of pH, carbon dioxide (CO2) and dissolved inorganic carbon (DIC) and other instruments from THOMAS G. THOMPSON in the Gulf of Alaska, North Pacific Ocean and South Pacific Ocean from 2006-02-13 to 2006-03-30 (NCEI Accession 0157411)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157411 includes Surface underway, chemical and physical data collected from THOMAS G. THOMPSON in the Gulf of Alaska, North Pacific Ocean and South...

  11. Empirical algorithms to estimate water column pH in the Southern Ocean

    Science.gov (United States)

    Williams, N. L.; Juranek, L. W.; Johnson, K. S.; Feely, R. A.; Riser, S. C.; Talley, L. D.; Russell, J. L.; Sarmiento, J. L.; Wanninkhof, R.

    2016-04-01

    Empirical algorithms are developed using high-quality GO-SHIP hydrographic measurements of commonly measured parameters (temperature, salinity, pressure, nitrate, and oxygen) that estimate pH in the Pacific sector of the Southern Ocean. The coefficients of determination, R2, are 0.98 for pH from nitrate (pHN) and 0.97 for pH from oxygen (pHOx) with RMS errors of 0.010 and 0.008, respectively. These algorithms are applied to Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) biogeochemical profiling floats, which include novel sensors (pH, nitrate, oxygen, fluorescence, and backscatter). These algorithms are used to estimate pH on floats with no pH sensors and to validate and adjust pH sensor data from floats with pH sensors. The adjusted float data provide, for the first time, seasonal cycles in surface pH on weekly resolution that range from 0.05 to 0.08 on weekly resolution for the Pacific sector of the Southern Ocean.

  12. A New Desalination Pump Helps Define the pH of Ocean Worlds

    Science.gov (United States)

    Levi, A.; Sasselov, D.

    2018-04-01

    We study ocean exoplanets, for which the global surface ocean is separated from the rocky interior by a high-pressure ice mantle. We describe a mechanism that can pump salts out of the ocean, resulting in oceans of very low salinity. Here we focus on the H2O–NaCl system, though we discuss the application of this pump to other salts as well. We find our ocean worlds to be acidic, with a pH in the range of 2–4. We discuss and compare between the conditions found within our studied oceans and the conditions in which polyextremophiles were discovered. This work focuses on exoplanets in the super-Earth mass range (∼2 M ⊕), with water composing at least a few percent of their mass. However, the principle of the desalination pump might extend beyond this mass range.

  13. Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from Surface underway, discrete sample and profile observations using CTD, Carbon dioxide (CO2) gas analyzer and other instruments from MAURICE EWING in the North Atlantic Ocean and South Atlantic Ocean from 1994-01-04 to 1994-03-21 (NODC Accession 0115157)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0115157 includes Surface underway, discrete sample and profile data collected from MAURICE EWING in the North Atlantic Ocean and South Atlantic Ocean...

  14. Changing noise levels in a high CO2/lower pH ocean

    Science.gov (United States)

    Brewer, P. G.; Hester, K. C.; Peltzer, E. T.; Kirkwood, W. J.

    2008-12-01

    We show that ocean acidification from fossil fuel CO2 invasion and from increased respiration/reduced ventilation, has significantly reduced ocean sound absorption and thus increased ocean noise levels in the kHz frequency range. Below 10 kHz, sound absorption occurs due to well known chemical relaxations in the B(OH)3/B(OH)4- and HCO3-/CO32- systems. The pH dependence of these chemical relaxations results in decreased sound absorption (α = dB/km) as the ocean becomes more acidic from increased CO2 levels. The scale of surface ocean pH change today from the +105 ppmv change in atmospheric CO2 is about - 0.12 pH, resulting in frequency dependent decreases in sound absorption that now exceed 12% over pre- industrial. Under reasonable projections of future fossil fuel CO2 emissions and other sources a pH change of 0.3 units or more can be anticipated by mid-century, resulting in a decrease in α by almost 40%. Increases in water temperature have a smaller effect but also contribute to decreased sound absorption. Combining a lowering of 0.3 pH units with an increase of 3°C, α will decrease further to almost 45%. Ambient noise levels in the ocean within the auditory range critical for environmental, military, and economic interests are set to increase significantly due to the combined effects of decreased absorption and increasing sources from mankind's activities. Incorporation of sound absorption in modeling future ocean scenarios (R. Zeebe, personal communication) and long-term monitoring possibly with the aid of modern cabled observatories can give insights in how ocean noise will continue to change and its effect on groups such as marine mammals which communicate in the affected frequency range.

  15. Ocean Health X-Prize testing of a Simplified Spectrophotometric pH Sensor

    Science.gov (United States)

    Darlington, R. C.; DeGrandpre, M. D.; Spaulding, R. S.; Beck, J. C.

    2016-02-01

    Since the Industrial Revolution, the world's oceans have absorbed increasing amounts of CO2, resulting in a >0.1 reduction in the pH of surface waters. This acidification of the oceans has many far reaching impacts on marine life. There is, therefore, great need of quality instrumentation to assess and follow the changing carbonate system. To address this need, we have developed a simplified spectrophotometric pH sensor with accuracy and precision suitable for sea surface measurements with special emphasis on reduced size and cost. The reduced size will allow deployment of sensors on a much wider variety of platforms than are currently possible, and the reduced cost will make the instruments available to a broader research community. This prototype pH instrument was entered into the Wendy Schmidt Ocean Health X-Prize, an incentivized global competition to spur innovation in sensors to monitor ocean acidification's impact on marine ecosystems. Results from the three phases of competition which explored accuracy, precision, and stability culminating in a one month field trial are detailed. The prototype proved to be highly accurate (+/-0.009), with good precision (+/-0.004) and stability showing drift indistinguishable from that of the validation measurements. The innovations that enabled this sensor to succeed in the competition could allow for deployment of spectrophotometric sensors on new platforms such as NOAAs Global Drifter Program, a network of non-recovered surface drifting buoys, which would greatly extend the spatial and temporal resolution of ocean acidification measurements.

  16. Breaking of ocean surface waves

    International Nuclear Information System (INIS)

    Babanin, A.V.

    2009-01-01

    Wind-generated waves are the most prominent feature of the ocean surface, and so are breaking waves manifested by the appearance of sporadic whitecaps. Such breaking represents one of the most interesting and most challenging problems for both fluid mechanics and physical oceanography. It is an intermittent random process, very fast by comparison with other processes in the wave breaking on the water surface is not continuous, but its role in maintaining the energy balance within the continuous wind-wave field is critical. Ocean wave breaking also plays the primary role in the air-sea exchange of momentum, mass and heat, and it is of significant importance for ocean remote sensing, coastal and maritime engineering, navigation and other practical applications. Understanding the wave breaking its occurrence, the breaking rates and even ability to describe its onset has been hindered for decades by the strong non-linearity of the process, together with its irregular and ferocious nature. Recently, this knowledge has significantly advanced, and the review paper is an attempt to summarise the facts into a consistent, albeit still incomplete picture of the phenomenon. In the paper, variety of definitions related to the were breaking are discussed and formulated and methods for breaking detection and measurements are examined. Most of attention is dedicated to the research of wave breaking probability and severity. Experimental, observational, numerical and statistical approaches and their outcomes are reviewed. Present state of the wave-breaking research and knowledge is analysed and main outstanding problems are outlined (Authors)

  17. Dissolved inorganic carbon, total alkalinity, pH, and other variables collected from surface discrete observations using Flow through pump and other instruments from M/V Skogafoss in the Northeastern U.S. continental shelf and off the southern coast of Greenland during the ocean acidification cruise SKO0313, SKO0406, SKO0410, SKO0414, SKO0510, SKO0604, SKO0611, SKO0721, SKO_1406, SKO_1501, SKO_1506, SKO_1509, SKO_1604 from 2003-12-06 to 2016-04-01 (NCEI Accession 0154380)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains surface measurements of dissolved inorganic carbon, total alkalinity, pH in the North Atlantic Ocean. Increasing amounts of...

  18. Low pH Springs - A Natural Laboratory for Ocean Acidification

    Science.gov (United States)

    Derse, E.; Rebolledo-Vieyra, M.; Potts, D. C.; Paytan, A.

    2009-12-01

    Recent increases in atmospheric carbon dioxide of 40% above pre-industrial levels has resulted in rising aqueous CO2 concentrations that lower the pH of the oceans. Currently, the surface ocean has an average pH between 8.1 and 8.2: it is estimated that over the next 100 years this value will decrease by ~0.4 pH units. Previous studies have highlighted the negative impacts that changes in pH (and the resulting CaCO3 saturation state) have on marine organisms; however, to date, very little is known about the long-term impacts of ocean acidification on ecosystems as a whole. The Yucatán Peninsula of Quintana Roo, Mexico, represents an ecosystem where naturally low pH groundwater (7.25-8.07) has been discharging offshore at highly localized points (called ojos) since the last deglaciation. We present preliminary chemical and biological data on a selection of ojos from lagoon sites in Puerto Morelos, Mexico. We address the potential long-term implications of low pH waters on marine ecosystems.

  19. Generalised expressions for the response of pH to changes in ocean chemistry

    Science.gov (United States)

    Hagens, Mathilde; Middelburg, Jack J.

    2016-08-01

    The extent to which oceans are capable of buffering chemical changes resulting from the uptake of carbon dioxide (CO2) or other acidifying processes can be quantified using buffer factors. Here, we present general expressions describing the sensitivity of pH and concentrations of CO2 and other acid-base species to a change in ocean chemistry. These expressions can include as many acid-base systems as desirable, making them suitable for application to, e.g., upwelling regions or nutrient-rich coastal waters. We show that these expressions are fully consistent with previously derived expressions for the Revelle factor and other buffer factors, which only included the carbonate and borate acid-base systems, and provide more accurate values. We apply our general expressions to contemporary global ocean surface water and possible changes therein by the end of the 21st century. These results show that most sensitivities describing a change in pH are of greater magnitude in a warmer, high-CO2 ocean, indicating a decreased seawater buffering capacity. This trend is driven by the increase in CO2 and slightly moderated by the warming. Respiration-derived carbon dioxide may amplify or attenuate ocean acidification due to rising atmospheric CO2, depending on their relative importance. Our work highlights that, to gain further insight into current and future pH dynamics, it is crucial to properly quantify the various concurrently acting buffering mechanisms.

  20. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from Surface underway, discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from MIRAI in the Bering Sea, North Pacific Ocean and South Pacific Ocean from 2007-10-08 to 2007-12-26 (NODC Accession 0108123)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0108123 includes Surface underway, discrete sample and profile data collected from MIRAI in the Bering Sea, North Pacific Ocean and South Pacific...

  1. pH (on total scale) and other variables collected from surface undewray observations using Durafet pH electrode and Chloride Ion Selective Electrode and other instruments from NOAA Ship Ronald H. Brown in the North Atlantic Ocean and South Atnaltic Ocean from during the CLIVAR/GO-SHIP Repeat Section A13.5_2010 (EXPOCODE 33RO20100308) from 2010-03-08 to 2010-04-17 (NCEI Accession 0162231)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — An automated underway pH system was operated in the hydro lab of NOAA Ship Ronald H. Brown during the CLIVAR/GO-SHIP Repeat Section A13.5 cruise in 2010. pH was...

  2. Simulation Tool for GNSS Ocean Surface Reflections

    DEFF Research Database (Denmark)

    Høeg, Per; von Benzon, Hans-Henrik; Durgonics, Tibor

    2015-01-01

    GNSS coherent and incoherent reflected signals have the potential of deriving large scale parameters of ocean surfaces, as barotropic variability, eddy currents and fronts, Rossby waves, coastal upwelling, mean ocean surfaceheights, and patterns of the general ocean circulation. In the reflection...... zone the measurements may deriveparameters as sea surface roughness, winds, waves, heights and tilts from the spectral measurements. Previous measurements from the top of mountains and airplanes have shown such results leading.The coming satellite missions, CYGNSS, COSMIC-2, and GEROS...

  3. Dynamic regulation of gastric surface pH by luminal pH

    OpenAIRE

    Chu, Shaoyou; Tanaka, Shin; Kaunitz, Jonathan D.; Montrose, Marshall H.

    1999-01-01

    In vivo confocal imaging of the mucosal surface of rat stomach was used to measure pH noninvasively under the mucus gel layer while simultaneously imaging mucus gel thickness and tissue architecture. When tissue was superfused at pH 3, the 25 μm adjacent to the epithelial surface was relatively alkaline (pH 4.1 ± 0.1), and surface alkalinity was enhanced by topical dimethyl prostaglandin E2 (pH 4.8 ± 0.2). Luminal pH was changed from pH 3 to pH 5 to mimic the fasted-to-fed transition in intra...

  4. Glacial--interglacial stability of ocean pH inferred from foraminifer dissolution rates.

    Science.gov (United States)

    Anderson, David M; Archer, David

    2002-03-07

    The pH of the ocean is controlled by the chemistry of calcium carbonate. This system in turn plays a large role in regulating the CO2 concentration of the atmosphere on timescales of thousands of years and longer. Reconstructions of ocean pH and carbonate-ion concentration are therefore needed to understand the ocean's role in the global carbon cycle. During the Last Glacial Maximum (LGM), the pH of the whole ocean is thought to have been significantly more basic, as inferred from the isotopic composition of boron incorporated into calcium carbonate shells, which would partially explain the lower atmospheric CO2 concentration at that time. Here we reconstruct carbonate-ion concentration--and hence pH--of the glacial oceans, using the extent of calcium carbonate dissolution observed in foraminifer faunal assemblages as compiled in the extensive global CLIMAP data set. We observe decreased carbonate-ion concentrations in the glacial Atlantic Ocean, by roughly 20 micromolkg-1, while little change occurred in the Indian and Pacific oceans relative to today. In the Pacific Ocean, a small (5 micromolkg-1) increase occurred below 3,000m. This rearrangement of ocean pH may be due to changing ocean circulation from glacial to present times, but overall we see no evidence for a shift in the whole-ocean pH as previously inferred from boron isotopes.

  5. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample, profile and underway - surface observations using Alkalinity titrator, CTD and other instruments from the MIRAI in the Bismarck Sea, North Pacific Ocean and South Pacific Ocean from 2005-05-25 to 2005-07-02 (NODC Accession 0108081)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0108081 includes chemical, discrete sample, physical, profile and underway - surface data collected from MIRAI in the Bismarck Sea, North Pacific...

  6. Turf algal epiphytes metabolically induce local pH increase, with implications for underlying coralline algae under ocean acidification

    DEFF Research Database (Denmark)

    Short, J.A.; Pedersen, Ole; Kendrick, G.A.

    2015-01-01

    The presence of epiphytic turf algae may modify the effects of ocean acidification on coralline algal calcification rates by altering seawater chemistry within the diffusive boundary layer (DBL) above coralline algal crusts. We used microelectrodes to measure the effects of turf algal epiphytes...... on seawater pH and the partial pressure of oxygen (pO2) within the DBL at the surface of Hydrolithoideae coralline algal crusts under ambient (36 Pa) CO2 and an ocean acidification scenario with elevated CO2 (200 Pa). Turf algae significantly increased the mean diel amplitude of pH and pO2, and this effect...... was more pronounced under elevated CO2. We suggest that increases in seawater CO2 under ocean acidification conditions may drive an increase in the abundance of epiphytic turf algae, consequently modifying the chemistry within the DBL. Thus, the effect of epiphytic turf algae on microscale pH is striking...

  7. Constraints on Europa's Ocean Composition Imposed by Its Surface Composition

    Science.gov (United States)

    Johnson, P. V.; Hodyss, R. P.; Vu, T. H.; Choukroun, M.

    2017-12-01

    Of the non-terrestrial environments within our Solar System, Europa's global liquid water ocean is arguably the most likely to be habitable. As such, understanding the habitability of Europa's ocean is of great interest to astrobiology and is the focus of missions currently being considered for further exploration of Europa. However, direct analysis of the ocean is unlikely in the foreseeable future. As such, our best means of constraining the subsurface ocean composition and its subsequent habitability currently is by further study of Europa's surface chemical composition. Recently, there has been a body of work published that looks at the chemistry of frozen brines representing putative ocean compositions. Here we take a simplified model of a four ionic component (Na, Mg, SO4, Cl) solution and map out what minerals are formed upon freezing as a function of relative ionic concentration, pH, etc. A `flow-chart' of the freezing sequence was developed based on both published and recently acquired experimental results. In performing this exercise, we are able to begin making meaningful links between observations of the surface chemistry and the chemical environment of the internal ocean.

  8. Natural variability in the surface ocean carbonate ion concentration

    Directory of Open Access Journals (Sweden)

    N. S. Lovenduski

    2015-11-01

    Full Text Available We investigate variability in the surface ocean carbonate ion concentration ([CO32−] on the basis of a~long control simulation with an Earth System Model. The simulation is run with a prescribed, pre-industrial atmospheric CO2 concentration for 1000 years, permitting investigation of natural [CO32−] variability on interannual to multi-decadal timescales. We find high interannual variability in surface [CO32−] in the tropical Pacific and at the boundaries between the subtropical and subpolar gyres in the Northern Hemisphere, and relatively low interannual variability in the centers of the subtropical gyres and in the Southern Ocean. Statistical analysis of modeled [CO32−] variance and autocorrelation suggests that significant anthropogenic trends in the saturation state of aragonite (Ωaragonite are already or nearly detectable at the sustained, open-ocean time series sites, whereas several decades of observations are required to detect anthropogenic trends in Ωaragonite in the tropical Pacific, North Pacific, and North Atlantic. The detection timescale for anthropogenic trends in pH is shorter than that for Ωaragonite, due to smaller noise-to-signal ratios and lower autocorrelation in pH. In the tropical Pacific, the leading mode of surface [CO32−] variability is primarily driven by variations in the vertical advection of dissolved inorganic carbon (DIC in association with El Niño–Southern Oscillation. In the North Pacific, surface [CO32−] variability is caused by circulation-driven variations in surface DIC and strongly correlated with the Pacific Decadal Oscillation, with peak spectral power at 20–30-year periods. North Atlantic [CO32−] variability is also driven by variations in surface DIC, and exhibits weak correlations with both the North Atlantic Oscillation and the Atlantic Multidecadal Oscillation. As the scientific community seeks to detect the anthropogenic influence on ocean carbonate chemistry, these results

  9. Natural variability in the surface ocean carbonate ion concentration

    Science.gov (United States)

    Lovenduski, N. S.; Long, M. C.; Lindsay, K.

    2015-11-01

    We investigate variability in the surface ocean carbonate ion concentration ([CO32-]) on the basis of a~long control simulation with an Earth System Model. The simulation is run with a prescribed, pre-industrial atmospheric CO2 concentration for 1000 years, permitting investigation of natural [CO32-] variability on interannual to multi-decadal timescales. We find high interannual variability in surface [CO32-] in the tropical Pacific and at the boundaries between the subtropical and subpolar gyres in the Northern Hemisphere, and relatively low interannual variability in the centers of the subtropical gyres and in the Southern Ocean. Statistical analysis of modeled [CO32-] variance and autocorrelation suggests that significant anthropogenic trends in the saturation state of aragonite (Ωaragonite) are already or nearly detectable at the sustained, open-ocean time series sites, whereas several decades of observations are required to detect anthropogenic trends in Ωaragonite in the tropical Pacific, North Pacific, and North Atlantic. The detection timescale for anthropogenic trends in pH is shorter than that for Ωaragonite, due to smaller noise-to-signal ratios and lower autocorrelation in pH. In the tropical Pacific, the leading mode of surface [CO32-] variability is primarily driven by variations in the vertical advection of dissolved inorganic carbon (DIC) in association with El Niño-Southern Oscillation. In the North Pacific, surface [CO32-] variability is caused by circulation-driven variations in surface DIC and strongly correlated with the Pacific Decadal Oscillation, with peak spectral power at 20-30-year periods. North Atlantic [CO32-] variability is also driven by variations in surface DIC, and exhibits weak correlations with both the North Atlantic Oscillation and the Atlantic Multidecadal Oscillation. As the scientific community seeks to detect the anthropogenic influence on ocean carbonate chemistry, these results will aid the interpretation of trends

  10. Field Performance of ISFET based Deep Ocean pH Sensors

    Science.gov (United States)

    Branham, C. W.; Murphy, D. J.

    2017-12-01

    Historically, ocean pH time series data was acquired from infrequent shipboard grab samples and measured using labor intensive spectrophotometry methods. However, with the introduction of robust and stable ISFET pH sensors for use in ocean applications a paradigm shift in the methods used to acquire long-term pH time series data has occurred. Sea-Bird Scientific played a critical role in the adoption this new technology by commercializing the SeaFET pH sensor and float pH Sensor developed by the MBARI chemical sensor group. Sea-Bird Scientific continues to advance this technology through a concerted effort to improve pH sensor accuracy and reliability by characterizing their performance in the laboratory and field. This presentation will focus on calibration of the ISFET pH sensor, evaluate its analytical performance, and validate performance using recent field data.

  11. Merged Land and Ocean Surface Temperature, Version 3.5

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The historical Merged Land-Ocean Surface Temperature Analysis (MLOST) is derived from two independent analyses, an Extended Reconstructed Sea Surface Temperature...

  12. Atmosphere-surface interactions over polar oceans and heterogeneous surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Vihma, T.

    1995-12-31

    Processes of interaction between the atmospheric boundary layer and the planetary surface have been studied with special emphasis on polar ocean surfaces: the open ocean, leads, polynyas and sea ice. The local exchange of momentum, heat and moisture has been studied experimentally both in the Weddell Sea and in the Greenland Sea. Exchange processes over heterogeneous surfaces are addressed by modelling studies. Over a homogeneous surface, the local turbulent fluxes can be reasonably well estimated using an iterative flux-profile scheme based on the Monin-Obukhov similarity theory. In the Greenland Sea, the near-surface air temperature and the generally small turbulent fluxes over the open ocean were affected by the sea surface temperature fronts. Over the sea ice cover in the Weddell Sea, the turbulent sensible heat flux was generally downwards, and together with an upward oceanic heat flux through the ice it compensated the heat loss from the surface via long-wave radiation. The wind dominated on time scales of days, while the current became important on longer time scales. The drift dynamics showed apparent spatial differences between the eastern and western regions, as well as between the Antarctic Circumpolar Current and the rest of the Weddell Sea. Inertial motion was present in regions of low ice concentration. The surface heterogeneity, arising e.g. from roughness or temperature distribution, poses a problem for the parameterization of surface exchange processes in large-scale models. In the case of neutral flow over a heterogeneous terrain, an effective roughness length can be used to parameterize the roughness effects

  13. Atmosphere-surface interactions over polar oceans and heterogeneous surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Vihma, T

    1996-12-31

    Processes of interaction between the atmospheric boundary layer and the planetary surface have been studied with special emphasis on polar ocean surfaces: the open ocean, leads, polynyas and sea ice. The local exchange of momentum, heat and moisture has been studied experimentally both in the Weddell Sea and in the Greenland Sea. Exchange processes over heterogeneous surfaces are addressed by modelling studies. Over a homogeneous surface, the local turbulent fluxes can be reasonably well estimated using an iterative flux-profile scheme based on the Monin-Obukhov similarity theory. In the Greenland Sea, the near-surface air temperature and the generally small turbulent fluxes over the open ocean were affected by the sea surface temperature fronts. Over the sea ice cover in the Weddell Sea, the turbulent sensible heat flux was generally downwards, and together with an upward oceanic heat flux through the ice it compensated the heat loss from the surface via long-wave radiation. The wind dominated on time scales of days, while the current became important on longer time scales. The drift dynamics showed apparent spatial differences between the eastern and western regions, as well as between the Antarctic Circumpolar Current and the rest of the Weddell Sea. Inertial motion was present in regions of low ice concentration. The surface heterogeneity, arising e.g. from roughness or temperature distribution, poses a problem for the parameterization of surface exchange processes in large-scale models. In the case of neutral flow over a heterogeneous terrain, an effective roughness length can be used to parameterize the roughness effects

  14. Ocean acidification reverses the positive effects of seawater pH fluctuations on growth and photosynthesis of the habitat-forming kelp, Ecklonia radiata.

    Science.gov (United States)

    Britton, Damon; Cornwall, Christopher E; Revill, Andrew T; Hurd, Catriona L; Johnson, Craig R

    2016-05-27

    Ocean acidification (OA) is the reduction in seawater pH due to the absorption of human-released CO2 by the world's oceans. The average surface oceanic pH is predicted to decline by 0.4 units by 2100. However, kelp metabolically modifies seawater pH via photosynthesis and respiration in some temperate coastal systems, resulting in daily pH fluctuations of up to ±0.45 units. It is unknown how these fluctuations in pH influence the growth and physiology of the kelp, or how this might change with OA. In laboratory experiments that mimicked the most extreme pH fluctuations measured within beds of the canopy-forming kelp Ecklonia radiata in Tasmania, the growth and photosynthetic rates of juvenile E. radiata were greater under fluctuating pH (8.4 in the day, 7.8 at night) than in static pH treatments (8.4, 8.1, 7.8). However, pH fluctuations had no effect on growth rates and a negative effect on photosynthesis when the mean pH of each treatment was reduced by 0.3 units. Currently, pH fluctuations have a positive effect on E. radiata but this effect could be reversed in the future under OA, which is likely to impact the future ecological dynamics and productivity of habitats dominated by E. radiata.

  15. Coralline algae elevate pH at the site of calcification under ocean acidification.

    Science.gov (United States)

    Cornwall, Christopher E; Comeau, Steeve; McCulloch, Malcolm T

    2017-10-01

    Coralline algae provide important ecosystem services but are susceptible to the impacts of ocean acidification. However, the mechanisms are uncertain, and the magnitude is species specific. Here, we assess whether species-specific responses to ocean acidification of coralline algae are related to differences in pH at the site of calcification within the calcifying fluid/medium (pH cf ) using δ 11 B as a proxy. Declines in δ 11 B for all three species are consistent with shifts in δ 11 B expected if B(OH) 4 - was incorporated during precipitation. In particular, the δ 11 B ratio in Amphiroa anceps was too low to allow for reasonable pH cf values if B(OH) 3 rather than B(OH) 4 - was directly incorporated from the calcifying fluid. This points towards δ 11 B being a reliable proxy for pH cf for coralline algal calcite and that if B(OH) 3 is present in detectable proportions, it can be attributed to secondary postincorporation transformation of B(OH) 4 - . We thus show that pH cf is elevated during calcification and that the extent is species specific. The net calcification of two species of coralline algae (Sporolithon durum, and Amphiroa anceps) declined under elevated CO 2 , as did their pH cf . Neogoniolithon sp. had the highest pH cf , and most constant calcification rates, with the decrease in pH cf being ¼ that of seawater pH in the treatments, demonstrating a control of coralline algae on carbonate chemistry at their site of calcification. The discovery that coralline algae upregulate pH cf under ocean acidification is physiologically important and should be included in future models involving calcification. © 2017 John Wiley & Sons Ltd.

  16. Late Archean Surface Ocean Oxygenation (Invited)

    Science.gov (United States)

    Kendall, B.; Reinhard, C.; Lyons, T. W.; Kaufman, A. J.; Anbar, A. D.

    2009-12-01

    Oxygenic photosynthesis must have evolved by 2.45-2.32 Ga, when atmospheric oxygen abundances first rose above 0.001% present atmospheric level (Great Oxidation Event; GOE). Biomarker evidence for a time lag between the evolution of cyanobacterial oxygenic photosynthesis and the GOE continues to be debated. Geochemical signatures from sedimentary rocks (redox-sensitive trace metal abundances, sedimentary Fe geochemistry, and S isotopes) represent an alternative tool for tracing the history of Earth surface oxygenation. Integrated high-resolution chemostratigraphic profiles through the 2.5 Ga Mt. McRae Shale (Pilbara Craton, Western Australia) suggest a ‘whiff’ of oxygen in the surface environment at least 50 M.y. prior to the GOE. However, the geochemical data from the Mt. McRae Shale does not uniquely constrain the presence or extent of Late Archean ocean oxygenation. Here, we present high-resolution chemostratigraphic profiles from 2.6-2.5 Ga black shales (upper Campbellrand Subgroup, Kaapvaal Craton, South Africa) that provide the earliest direct evidence for an oxygenated ocean water column. On the slope beneath the Campbellrand - Malmani carbonate platform (Nauga Formation), a mildly oxygenated water column (highly reactive iron to total iron ratios [FeHR/FeT] ≤ 0.4) was underlain by oxidizing sediments (low Re and Mo abundances) or mildly reducing sediments (high Re but low Mo abundances). After drowning of the carbonate platform (Klein Naute Formation), the local bottom waters became anoxic (FeHR/FeT > 0.4) and intermittently sulphidic (pyrite iron to highly reactive iron ratios [FePY/FeHR] > 0.8), conducive to enrichment of both Re and Mo in sediments, followed by anoxic and Fe2+-rich (ferruginous) conditions (high FeT, FePY/FeHR near 0). Widespread surface ocean oxygenation is suggested by Re enrichment in the broadly correlative Klein Naute Formation and Mt. McRae Shale, deposited ~1000 km apart in the Griqualand West and Hamersley basins

  17. High-frequency dynamics of ocean pH: a multi-ecosystem comparison.

    Directory of Open Access Journals (Sweden)

    Gretchen E Hofmann

    Full Text Available The effect of Ocean Acidification (OA on marine biota is quasi-predictable at best. While perturbation studies, in the form of incubations under elevated pCO(2, reveal sensitivities and responses of individual species, one missing link in the OA story results from a chronic lack of pH data specific to a given species' natural habitat. Here, we present a compilation of continuous, high-resolution time series of upper ocean pH, collected using autonomous sensors, over a variety of ecosystems ranging from polar to tropical, open-ocean to coastal, kelp forest to coral reef. These observations reveal a continuum of month-long pH variability with standard deviations from 0.004 to 0.277 and ranges spanning 0.024 to 1.430 pH units. The nature of the observed variability was also highly site-dependent, with characteristic diel, semi-diurnal, and stochastic patterns of varying amplitudes. These biome-specific pH signatures disclose current levels of exposure to both high and low dissolved CO(2, often demonstrating that resident organisms are already experiencing pH regimes that are not predicted until 2100. Our data provide a first step toward crystallizing the biophysical link between environmental history of pH exposure and physiological resilience of marine organisms to fluctuations in seawater CO(2. Knowledge of this spatial and temporal variation in seawater chemistry allows us to improve the design of OA experiments: we can test organisms with a priori expectations of their tolerance guardrails, based on their natural range of exposure. Such hypothesis-testing will provide a deeper understanding of the effects of OA. Both intuitively simple to understand and powerfully informative, these and similar comparative time series can help guide management efforts to identify areas of marine habitat that can serve as refugia to acidification as well as areas that are particularly vulnerable to future ocean change.

  18. Generalised expressions for the response of pH to changes in ocean chemistry

    NARCIS (Netherlands)

    Hagens, M.; Middelburg, J.B.M.

    2016-01-01

    The extent to which oceans are capable of buffering chemical changes resulting from the uptake of carbon dioxide (CO2) or other acidifying processes can be quantified using buffer factors. Here, we present general expressions describing the sensitivity of pH and concentrations of CO2 and other

  19. Ka-band Doppler Scatterometer for Measurements of Ocean Vector Winds and Surface Currents

    Data.gov (United States)

    National Aeronautics and Space Administration — Ocean surface currents impact heat transport, surface momentum and gas fluxes, ocean productivity and marine biological communities. Ocean currents also have social...

  20. Empirical Algorithms to Predict pH and Aragonite Saturation State on SOCCOM Biogeochemical Argo Floats in the Pacific Sector of the Southern Ocean

    Science.gov (United States)

    Williams, N. L.; Juranek, L. W.; Feely, R. A.; Johnson, K. S.; Russell, J. L.

    2016-02-01

    The Southern Ocean plays a major role in the global uptake, transport, and storage of both heat and carbon, yet it remains one of the least-sampled regions of the ocean. The Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) project aims to fill the observational gaps by deploying over 200 autonomous profiling floats in the Southern Ocean over the next several years. Initial float deployments have greatly expanded our observational capability to include wintertime measurements as well as under-ice measurements, and many of these floats include novel biogeochemical sensors (pH, nitrate, oxygen). Here we present empirical algorithms that can be used to predict pH and ΩAragonite from other float-measured parameters (temperature, salinity, pressure, nitrate, oxygen). These algorithms were trained using bottle measurements from high-quality repeat hydrographic GO-SHIP cruises. We obtained R2 values of 0.98 (pH) and 0.99 (ΩAragonite) and RMS errors of 0.007 (pH) and 0.052 (ΩAragonite) for data between 100-1500 m. These algorithms will allow us to both validate pH data from these sensors, as well as predict ΩAragonite and pH on floats that do not have pH sensors. Here we present estimated pH and ΩAragonite over 20 months of deployment for several SOCCOM floats in the Pacific Sector of the Southern Ocean. The results show seasonal ranges in surface pH and ΩAragonite of 0.05 and 0.1, respectively.

  1. Breaking Waves on the Ocean Surface

    Science.gov (United States)

    Schwendeman, Michael S.

    In the open ocean, breaking waves are a critical mechanism for the transfer of energy, momentum, and mass between the atmosphere and the ocean. Despite much study, fundamental questions about wave breaking, such as what determines whether a wave will break, remain unresolved. Measurements of oceanic breakers, or "whitecaps," are often used to validate the hypotheses derived in simplified theoretical, numerical, or experimental studies. Real-world measurements are also used to improve the parameterizations of wave-breaking in large global models, such as those forecasting climate change. Here, measurements of whitecaps are presented using ship-based cameras, from two experiments in the North Pacific Ocean. First, a method for georectifying the camera imagery is described using the distant horizon, without additional instrumentation. Over the course of the experiment, this algorithm correctly identifies the horizon in 92% of images in which it is visible. In such cases, the calculation of camera pitch and roll is accurate to within 1 degree. The main sources of error in the final georectification are from mislabeled horizons due to clouds, rain, or poor lighting, and from vertical "heave" motions of the camera, which cannot be calculated with the horizon method. This method is used for correcting the imagery from the first experiment, and synchronizing the imagery from the second experiment to an onboard inertial motion package. Next, measurements of the whitecap coverage, W, are shown from both experiments. Although W is often used in models to represent whitecapping, large uncertainty remains in the existing parameterizations. The data show good agreement with recent measurements using the wind speed. Although wave steepness and dissipation are hypothesized to be more robust predictors of W, this is shown to not always be the case. Wave steepness shows comparable success to the wind parameterizations only when using a mean-square slope variable calculated over the

  2. Ocean acidification and kelp development: Reduced pH has no negative effects on meiospore germination and gametophyte development of Macrocystis pyrifera and Undaria pinnatifida.

    Science.gov (United States)

    Leal, Pablo P; Hurd, Catriona L; Fernández, Pamela A; Roleda, Michael Y

    2017-06-01

    The absorption of anthropogenic CO 2 by the oceans is causing a reduction in the pH of the surface waters termed ocean acidification (OA). This could have substantial effects on marine coastal environments where fleshy (non-calcareous) macroalgae are dominant primary producers and ecosystem engineers. Few OA studies have focused on the early life stages of large macroalgae such as kelps. This study evaluated the effects of seawater pH on the ontogenic development of meiospores of the native kelp Macrocystis pyrifera and the invasive kelp Undaria pinnatifida, in south-eastern New Zealand. Meiospores of both kelps were released into four seawater pH treatments (pH T 7.20, extreme OA predicted for 2300; pH T 7.65, OA predicted for 2100; pH T 8.01, ambient pH; and pH T 8.40, pre-industrial pH) and cultured for 15 d. Meiospore germination, germling growth rate, and gametophyte size and sex ratio were monitored and measured. Exposure to reduced pH T (7.20 and 7.65) had positive effects on germling growth rate and gametophyte size in both M. pyrifera and U. pinnatifida, whereas, higher pH T (8.01 and 8.40) reduced the gametophyte size in both kelps. Sex ratio of gametophytes of both kelps was biased toward females under all pH T treatments, except for U. pinnatifida at pH T 7.65. Germling growth rate under OA was significantly higher in M. pyrifera compared to U. pinnatifida but gametophyte development was equal for both kelps under all seawater pH T treatments, indicating that the microscopic stages of the native M. pyrifera and the invasive U. pinnatifida will respond similarly to OA. © 2017 Phycological Society of America.

  3. Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample, profile and underway - surface observations using Alkalinity titrator, CTD and other instruments from the MIRAI in the Coral Sea, North Pacific Ocean and others from 2009-04-10 to 2009-07-03 (NODC Accession 0108084)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0108084 includes chemical, discrete sample, meteorological, physical, profile and underway - surface data collected from MIRAI in the Coral Sea, North...

  4. Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample, profile and underway - surface observations using CTD, Carbon dioxide (CO2) gas analyzer and other instruments from the METEOR in the South Atlantic Ocean from 1992-12-27 to 1993-01-31 (NODC Accession 0115173)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115173 includes chemical, discrete sample, meteorological, physical, profile and underway - surface data collected from METEOR in the South Atlantic...

  5. Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, pH, alkalinity, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from Benguela Stream in the Caribbean Sea, English Channel and North Atlantic Ocean from 2011-01-08 to 2011-12-29 (NCEI Accession 0157237)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157237 includes Surface underway, biological, chemical, meteorological, optical and physical data collected from Benguela Stream in the Caribbean...

  6. Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, pH, alkalinity, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from Benguela Stream in the Caribbean Sea, English Channel and North Atlantic Ocean from 2012-01-07 to 2012-09-03 (NCEI Accession 0157312)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157312 includes Surface underway, biological, chemical, meteorological, optical and physical data collected from Benguela Stream in the Caribbean...

  7. Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, pH, alkalinity, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from Benguela Stream in the Caribbean Sea, English Channel and North Atlantic Ocean from 2013-09-18 to 2014-01-05 (NCEI Accession 0157352)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157352 includes Surface underway, biological, chemical, meteorological, optical and physical data collected from Benguela Stream in the Caribbean...

  8. Advancing Ocean Acidification Biology Using Durafet® pH Electrodes

    Directory of Open Access Journals (Sweden)

    Lydia Kapsenberg

    2017-10-01

    Full Text Available Research assessing the biological impacts of global ocean change often requires a burdensome characterization of seawater carbonate chemistry. For laboratory-based ocean acidification research, this impedes the scope of experimental design. Honeywell Durafet® III pH electrodes provide precise and continuous seawater pH measurements. In addition to use in oceanographic sensor packages, Durafets can also be used in the laboratory to track and control seawater treatments via Honeywell Universal Dual Analyzers (UDAs. Here we provide performance data, instructions, and step-by-step recommendations for use of multiple UDA-Durafets. Durafet pH measurements were within ±0.005 units pHT of spectrophotometric measurements and agreement among eight Durafets was better than ±0.005 units pHT. These results indicate equal performance to Durafets in oceanographic sensor packages, but methods for calibration and quality control differ. Use of UDA-Durafets vastly improves time-course documentation of experimental conditions and reduces person-hours dedicated to this activity. Due to the versatility of integrating Durafets in laboratory seawater systems, this technology opens the door to advance the scale of questions that the ocean acidification research community aims to address.

  9. Near-shore Antarctic pH variability has implications for the design of ocean acidification experiments

    Science.gov (United States)

    Kapsenberg, Lydia; Kelley, Amanda L.; Shaw, Emily C.; Martz, Todd R.; Hofmann, Gretchen E.

    2015-01-01

    Understanding how declining seawater pH caused by anthropogenic carbon emissions, or ocean acidification, impacts Southern Ocean biota is limited by a paucity of pH time-series. Here, we present the first high-frequency in-situ pH time-series in near-shore Antarctica from spring to winter under annual sea ice. Observations from autonomous pH sensors revealed a seasonal increase of 0.3 pH units. The summer season was marked by an increase in temporal pH variability relative to spring and early winter, matching coastal pH variability observed at lower latitudes. Using our data, simulations of ocean acidification show a future period of deleterious wintertime pH levels potentially expanding to 7–11 months annually by 2100. Given the presence of (sub)seasonal pH variability, Antarctica marine species have an existing physiological tolerance of temporal pH change that may influence adaptation to future acidification. Yet, pH-induced ecosystem changes remain difficult to characterize in the absence of sufficient physiological data on present-day tolerances. It is therefore essential to incorporate natural and projected temporal pH variability in the design of experiments intended to study ocean acidification biology.

  10. Warming and surface ocean acidification over the last deglaciation: implications for foraminiferal assemblages

    Science.gov (United States)

    Dyez, K. A.; Hoenisch, B.; deMenocal, P. B.

    2017-12-01

    Although plankton drift with ocean currents, their presence and relative abundance varies across latitudes and environmental seawater conditions (e.g. temperature, pH, salinity). While earlier studies have focused on temperature as the primary factor for determining the regional species composition of planktic foraminiferal communities, evidence has recently been presented that foraminiferal shell thickness varies with ocean pH, and it remains unclear whether ongoing ocean acidification will cause ecological shifts within this plankton group. The transition from the last glacial maximum (LGM; 19,000-23,000 years B.P.) to the late Holocene (0-5,000 years B.P.) was characterized by both warming and acidification of the surface ocean, and thus provides an opportunity to study ecosystem shifts in response to these environmental changes. Here we provide new δ11B, Mg/Ca, and δ18O measurements from a suite of global sediment cores spanning this time range. We use these geochemical data to reconstruct ocean temperature, pH and salinity and pair the new data with previously published analyses of planktic foraminifera assemblages to study the respective effects of ocean warming and acidification on the foraminiferal habitat. At most open-ocean sample locations, our proxies indicate warming and acidification similar to previously published estimates, but in some marginal seas and coastal locations pH changes little between over the glacial termination. At face value, these observations suggest that warming is generally more important for ecosystem changes than acidification, at least over the slow rates of warming and ocean acidification in this time period. While geochemical data collection is being completed, we aim to include these data in an ecological model of foraminiferal habitat preferences.

  11. Coral calcifying fluid pH dictates response to ocean acidification.

    Science.gov (United States)

    Holcomb, M; Venn, A A; Tambutté, E; Tambutté, S; Allemand, D; Trotter, J; McCulloch, M

    2014-06-06

    Ocean acidification driven by rising levels of CO2 impairs calcification, threatening coral reef growth. Predicting how corals respond to CO2 requires a better understanding of how calcification is controlled. Here we show how spatial variations in the pH of the internal calcifying fluid (pHcf) in coral (Stylophora pistillata) colonies correlates with differential sensitivity of calcification to acidification. Coral apexes had the highest pHcf and experienced the smallest changes in pHcf in response to acidification. Lateral growth was associated with lower pHcf and greater changes with acidification. Calcification showed a pattern similar to pHcf, with lateral growth being more strongly affected by acidification than apical. Regulation of pHcf is therefore spatially variable within a coral and critical to determining the sensitivity of calcification to ocean acidification.

  12. Transcriptomic responses to ocean acidification in larval sea urchins from a naturally variable pH environment.

    Science.gov (United States)

    Evans, Tyler G; Chan, Francis; Menge, Bruce A; Hofmann, Gretchen E

    2013-03-01

    Some marine ecosystems already experience natural declines in pH approximating those predicted with future anthropogenic ocean acidification (OA), the decline in seawater pH caused by the absorption of atmospheric CO2 . The molecular mechanisms that allow organisms to inhabit these low pH environments, particularly those building calcium carbonate skeletons, are unknown. Also uncertain is whether an enhanced capacity to cope with present day pH variation will confer resistance to future OA. To address these issues, we monitored natural pH dynamics within an intertidal habitat in the Northeast Pacific, demonstrating that upwelling exposes resident species to pH regimes not predicted to occur elsewhere until 2100. Next, we cultured the progeny of adult purple sea urchins (Strongylocentrotus purpuratus) collected from this region in CO2 -acidified seawater representing present day and near future ocean scenarios and monitored gene expression using transcriptomics. We hypothesized that persistent exposure to upwelling during evolutionary history will have selected for increased pH tolerance in this population and that their transcriptomic response to low pH seawater would provide insight into mechanisms underlying pH tolerance in a calcifying species. Resulting expression patterns revealed two important trends. Firstly, S. purpuratus larvae may alter the bioavailability of calcium and adjust skeletogenic pathways to sustain calcification in a low pH ocean. Secondly, larvae use different strategies for coping with different magnitudes of pH stress: initiating a robust transcriptional response to present day pH regimes but a muted response to near future conditions. Thus, an enhanced capacity to cope with present day pH variation may not translate into success in future oceans. © 2013 Blackwell Publishing Ltd.

  13. The timescales of global surface-ocean connectivity.

    Science.gov (United States)

    Jönsson, Bror F; Watson, James R

    2016-04-19

    Planktonic communities are shaped through a balance of local evolutionary adaptation and ecological succession driven in large part by migration. The timescales over which these processes operate are still largely unresolved. Here we use Lagrangian particle tracking and network theory to quantify the timescale over which surface currents connect different regions of the global ocean. We find that the fastest path between two patches--each randomly located anywhere in the surface ocean--is, on average, less than a decade. These results suggest that marine planktonic communities may keep pace with climate change--increasing temperatures, ocean acidification and changes in stratification over decadal timescales--through the advection of resilient types.

  14. An Optimization Method for Virtual Globe Ocean Surface Dynamic Visualization

    Directory of Open Access Journals (Sweden)

    HUANG Wumeng

    2016-12-01

    Full Text Available The existing visualization method in the virtual globe mainly uses the projection grid to organize the ocean grid. This special grid organization has the defects in reflecting the difference characteristics of different ocean areas. The method of global ocean visualization based on global discrete grid can make up the defect of the projection grid method by matching with the discrete space of the virtual globe, so it is more suitable for the virtual ocean surface simulation application.But the available global discrete grids method has many problems which limiting its application such as the low efficiency of rendering and loading, the need of repairing grid crevices. To this point, we propose an optimization for the global discrete grids method. At first, a GPU-oriented multi-scale grid model of ocean surface which develops on the foundation of global discrete grids was designed to organize and manage the ocean surface grids. Then, in order to achieve the wind-drive wave dynamic rendering, this paper proposes a dynamic wave rendering method based on the multi-scale ocean surface grid model to support real-time wind field updating. At the same time, considering the effect of repairing grid crevices on the system efficiency, this paper presents an efficient method for repairing ocean surface grid crevices based on the characteristics of ocean grid and GPU technology. At last, the feasibility and validity of the method are verified by the comparison experiment. The experimental results show that the proposed method is efficient, stable and fast, and can compensate for the lack of function of the existing methods, so the application range is more extensive.

  15. Ocean surface partitioning strategies using ocean colour remote Sensing: A review

    Science.gov (United States)

    Krug, Lilian Anne; Platt, Trevor; Sathyendranath, Shubha; Barbosa, Ana B.

    2017-06-01

    The ocean surface is organized into regions with distinct properties reflecting the complexity of interactions between environmental forcing and biological responses. The delineation of these functional units, each with unique, homogeneous properties and underlying ecosystem structure and dynamics, can be defined as ocean surface partitioning. The main purposes and applications of ocean partitioning include the evaluation of particular marine environments; generation of more accurate satellite ocean colour products; assimilation of data into biogeochemical and climate models; and establishment of ecosystem-based management practices. This paper reviews the diverse approaches implemented for ocean surface partition into functional units, using ocean colour remote sensing (OCRS) data, including their purposes, criteria, methods and scales. OCRS offers a synoptic, high spatial-temporal resolution, multi-decadal coverage of bio-optical properties, relevant to the applications and value of ocean surface partitioning. In combination with other biotic and/or abiotic data, OCRS-derived data (e.g., chlorophyll-a, optical properties) provide a broad and varied source of information that can be analysed using different delineation methods derived from subjective, expert-based to unsupervised learning approaches (e.g., cluster, fuzzy and empirical orthogonal function analyses). Partition schemes are applied at global to mesoscale spatial coverage, with static (time-invariant) or dynamic (time-varying) representations. A case study, the highly heterogeneous area off SW Iberian Peninsula (NE Atlantic), illustrates how the selection of spatial coverage and temporal representation affects the discrimination of distinct environmental drivers of phytoplankton variability. Advances in operational oceanography and in the subject area of satellite ocean colour, including development of new sensors, algorithms and products, are among the potential benefits from extended use, scope and

  16. Variability in larval gut pH regulation defines sensitivity to ocean acidification in six species of the Ambulacraria superphylum.

    Science.gov (United States)

    Hu, Marian; Tseng, Yung-Che; Su, Yi-Hsien; Lein, Etienne; Lee, Hae-Gyeong; Lee, Jay-Ron; Dupont, Sam; Stumpp, Meike

    2017-10-11

    The unusual rate and extent of environmental changes due to human activities may exceed the capacity of marine organisms to deal with this phenomenon. The identification of physiological systems that set the tolerance limits and their potential for phenotypic buffering in the most vulnerable ontogenetic stages become increasingly important to make large-scale projections. Here, we demonstrate that the differential sensitivity of non-calcifying Ambulacraria (echinoderms and hemichordates) larvae towards simulated ocean acidification is dictated by the physiology of their digestive systems. Gastric pH regulation upon experimental ocean acidification was compared in six species of the superphylum Ambulacraria. We observed a strong correlation between sensitivity to ocean acidification and the ability to regulate gut pH. Surprisingly, species with tightly regulated gastric pH were more sensitive to ocean acidification. This study provides evidence that strict maintenance of highly alkaline conditions in the larval gut of Ambulacraria early life stages may dictate their sensitivity to decreases in seawater pH. These findings highlight the importance of identifying and understanding pH regulatory systems in marine larval stages that may contribute to substantial energetic challenges under near-future ocean acidification scenarios. © 2017 The Author(s).

  17. Evaluation of OSCAR ocean surface current product in the tropical ...

    Indian Academy of Sciences (India)

    Next, the evaluation has been carried out by comparing the OSCAR currents with currents measured by moored buoys ... measurements, to derive the surface current prod- uct, known ... ogy of surface currents based on drifter data. The ... and prediction (RAMA). ..... of satellite derived forcings on numerical ocean model sim-.

  18. Indian Ocean surface winds from NCMRWF analysis as compared

    Indian Academy of Sciences (India)

    The quality of the surface wind analysis at the National Centre for Medium Range Weather Forecasts (NCMRWF), New Delhi over the tropical Indian Ocean and its improvement in 2001 are examined by comparing it with in situ buoy measurements and satellite derived surface winds from NASA QuikSCAT satellite (QSCT) ...

  19. The influence of Southern Ocean surface buoyancy forcing on glacial-interglacial changes in the global deep ocean stratification

    OpenAIRE

    Sun, S; Eisenman, I; Stewart, AL

    2016-01-01

    ©2016. American Geophysical Union. All Rights Reserved. Previous studies have suggested that the global ocean density stratification below ∼3000 m is approximately set by its direct connection to the Southern Ocean surface density, which in turn is constrained by the atmosphere. Here the role of Southern Ocean surface forcing in glacial-interglacial stratification changes is investigated using a comprehensive climate model and an idealized conceptual model. Southern Ocean surface forcing is f...

  20. Ocean Surface Current Vectors from MODIS Terra/Aqua Sea Surface Temperature Image Pairs, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Satellites that record imagery of the same sea surface area, at times separated by a few hours, can be used to estimate ocean surface velocity fields based on the...

  1. Surface wind mixing in the Regional Ocean Modeling System (ROMS)

    Science.gov (United States)

    Robertson, Robin; Hartlipp, Paul

    2017-12-01

    Mixing at the ocean surface is key for atmosphere-ocean interactions and the distribution of heat, energy, and gases in the upper ocean. Winds are the primary force for surface mixing. To properly simulate upper ocean dynamics and the flux of these quantities within the upper ocean, models must reproduce mixing in the upper ocean. To evaluate the performance of the Regional Ocean Modeling System (ROMS) in replicating the surface mixing, the results of four different vertical mixing parameterizations were compared against observations, using the surface mixed layer depth, the temperature fields, and observed diffusivities for comparisons. The vertical mixing parameterizations investigated were Mellor- Yamada 2.5 level turbulent closure (MY), Large- McWilliams- Doney Kpp (LMD), Nakanishi- Niino (NN), and the generic length scale (GLS) schemes. This was done for one temperate site in deep water in the Eastern Pacific and three shallow water sites in the Baltic Sea. The model reproduced the surface mixed layer depth reasonably well for all sites; however, the temperature fields were reproduced well for the deep site, but not for the shallow Baltic Sea sites. In the Baltic Sea, the models overmixed the water column after a few days. Vertical temperature diffusivities were higher than those observed and did not show the temporal fluctuations present in the observations. The best performance was by NN and MY; however, MY became unstable in two of the shallow simulations with high winds. The performance of GLS nearly as good as NN and MY. LMD had the poorest performance as it generated temperature diffusivities that were too high and induced too much mixing. Further observational comparisons are needed to evaluate the effects of different stratification and wind conditions and the limitations on the vertical mixing parameterizations.

  2. Perfluoroalkylated substances in the global tropical and subtropical surface oceans.

    Science.gov (United States)

    González-Gaya, Belén; Dachs, Jordi; Roscales, Jose L; Caballero, Gemma; Jiménez, Begoña

    2014-11-18

    In this study, perfluoroalkylated substances (PFASs) were analyzed in 92 surface seawater samples taken during the Malaspina 2010 expedition which covered all the tropical and subtropical Atlantic, Pacific and Indian oceans. Nine ionic PFASs including C6-C10 perfluoroalkyl carboxylic acids (PFCAs), C4 and C6-C8 perfluoroalkyl sulfonic acids (PFSAs) and two neutral precursors perfluoroalkyl sulfonamides (PFASAs), were identified and quantified. The Atlantic Ocean presented the broader range in concentrations of total PFASs (131-10900 pg/L, median 645 pg/L, n = 45) compared to the other oceanic basins, probably due to a better spatial coverage. Total concentrations in the Pacific ranged from 344 to 2500 pg/L (median = 527 pg/L, n = 27) and in the Indian Ocean from 176 to 1976 pg/L (median = 329, n = 18). Perfluorooctanesulfonic acid (PFOS) was the most abundant compound, accounting for 33% of the total PFASs globally, followed by perfluorodecanoic acid (PFDA, 22%) and perfluorohexanoic acid (PFHxA, 12%), being the rest of the individual congeners under 10% of total PFASs, even for perfluorooctane carboxylic acid (PFOA, 6%). PFASAs accounted for less than 1% of the total PFASs concentration. This study reports the ubiquitous occurrence of PFCAs, PFSAs, and PFASAs in the global ocean, being the first attempt, to our knowledge, to show a comprehensive assessment in surface water samples collected in a single oceanic expedition covering tropical and subtropical oceans. The potential factors affecting their distribution patterns were assessed including the distance to coastal regions, oceanic subtropical gyres, currents and biogeochemical processes. Field evidence of biogeochemical controls on the occurrence of PFASs was tentatively assessed considering environmental variables (solar radiation, temperature, chlorophyll a concentrations among others), and these showed significant correlations with some PFASs, but explaining small to moderate percentages of variability

  3. The Proposed Surface Water and Ocean Topography (SWOT) Mission

    Science.gov (United States)

    Fu, Lee-Lueng; Alsdorf, Douglas; Rodriguez, Ernesto; Morrow, Rosemary; Mognard, Nelly; Vaze, Parag; Lafon, Thierry

    2012-01-01

    A new space mission concept called Surface Water and Ocean Topography (SWOT) is being developed jointly by a collaborative effort of the international oceanographic and hydrological communities for making high-resolution measurement of the water elevation of both the ocean and land surface water to answer the questions about the oceanic submesoscale processes and the storage and discharge of land surface water. The key instrument payload would be a Ka-band radar interferometer capable of making high-resolution wide-swath altimetry measurement. This paper describes the proposed science objectives and requirements as well as the measurement approach of SWOT, which is baselined to be launched in 2019. SWOT would demonstrate this new approach to advancing both oceanography and land hydrology and set a standard for future altimetry missions.

  4. View-Dependent Tessellation and Simulation of Ocean Surfaces

    Directory of Open Access Journals (Sweden)

    Anna Puig-Centelles

    2014-01-01

    Full Text Available Modeling and rendering realistic ocean scenes have been thoroughly investigated for many years. Its appearance has been studied and it is possible to find very detailed simulations where a high degree of realism is achieved. Nevertheless, among the solutions to ocean rendering, real-time management of the huge heightmaps that are necessary for rendering an ocean scene is still not solved. We propose a new technique for simulating the ocean surface on GPU. This technique is capable of offering view-dependent approximations of the mesh while maintaining coherence among the extracted approximations. This feature is very important as most solutions previously presented must retessellate from the initial mesh. Our solution is able to use the latest extracted approximation when refining or coarsening the mesh.

  5. Iridium Oxide pH Sensor Based on Stainless Steel Wire for pH Mapping on Metal Surface

    Science.gov (United States)

    Shahrestani, S.; Ismail, M. C.; Kakooei, S.; Beheshti, M.; Zabihiazadboni, M.; Zavareh, M. A.

    2018-03-01

    A simple technique to fabricate the iridium oxide pH sensor is useful in several applications such as medical, food processing and engineering material where it is able to detect the changes of pH. Generally, the fabrication technique can be classified into three types: electro-deposition iridium oxide film (EIrOF), activated iridium oxide film (AIROF) and sputtering iridium oxide film (SIROF). This study focuses on fabricating electrode, calibration and test. Electro-deposition iridium oxide film is a simple and effective method of fabricating this kind of sensor via cyclic voltammetry process. The iridium oxide thick film was successfully electrodeposited on the surface of stainless steel wire with 500 cycles of sweep potential. A further analysis under FESEM shows detailed image of iridium oxide film which has cauliflower-liked microstructure. EDX analysis shows the highest element present are iridium and oxygen which concluded that the process is successful. The iridium oxide based pH sensor has shown a good performance in comparison to conventional glass pH sensor when it is being calibrated in buffer solutions with 2, 4, 7 and 9 pH values. The iridium oxide pH sensor is specifically designed to measure the pH on the surface of metal plate.

  6. Dynamic patterns and ecological impacts of declining ocean pH in a high-resolution multi-year dataset.

    Science.gov (United States)

    Wootton, J Timothy; Pfister, Catherine A; Forester, James D

    2008-12-02

    Increasing global concentrations of atmospheric CO(2) are predicted to decrease ocean pH, with potentially severe impacts on marine food webs, but empirical data documenting ocean pH over time are limited. In a high-resolution dataset spanning 8 years, pH at a north-temperate coastal site declined with increasing atmospheric CO(2) levels and varied substantially in response to biological processes and physical conditions that fluctuate over multiple time scales. Applying a method to link environmental change to species dynamics via multispecies Markov chain models reveals strong links between in situ benthic species dynamics and variation in ocean pH, with calcareous species generally performing more poorly than noncalcareous species in years with low pH. The models project the long-term consequences of these dynamic changes, which predict substantial shifts in the species dominating the habitat as a consequence of both direct effects of reduced calcification and indirect effects arising from the web of species interactions. Our results indicate that pH decline is proceeding at a more rapid rate than previously predicted in some areas, and that this decline has ecological consequences for near shore benthic ecosystems.

  7. Sea surface microlayer in a changing ocean – A perspective

    Directory of Open Access Journals (Sweden)

    Oliver Wurl

    2017-06-01

    Full Text Available The sea surface microlayer (SML is the boundary interface between the atmosphere and ocean, covering about 70% of the Earth’s surface. With an operationally defined thickness between 1 and 1000 μm, the SML has physicochemical and biological properties that are measurably distinct from underlying waters. Recent studies now indicate that the SML covers the ocean to a significant extent, and evidence shows that it is an aggregate-enriched biofilm environment with distinct microbial communities. Because of its unique position at the air-sea interface, the SML is central to a range of global biogeochemical and climate-related processes. The redeveloped SML paradigm pushes the SML into a new and wider context that is relevant to many ocean and climate sciences.

  8. Reduction in Surface Ocean Carbon Storage across the Middle Miocene

    Science.gov (United States)

    Babila, T. L.; Sosdian, S. M.; Foster, G. L.; Lear, C. H.

    2017-12-01

    During the Middle Miocene, Earth underwent a profound climate shift from the warmth of the Miocene Climatic Optimum (MCO; 14-17 Ma) to the stable icehouse of today during the Middle Miocene Climate transition (MMCT). Elevated atmospheric carbon dioxide concentrations (pCO2) revealed by boron isotope records (δ11B) link massive volcanic outputs of Columbia River Flood Basalts to the general warmth of MCO. Superimposed on the long-term cooling trend (MMCT) is a gradual pCO2 decline and numerous positive carbon isotope (δ13C) excursions that indicate dynamic variations in the global carbon cycle. Enhanced organic carbon burial via marine productivity, increased silicate weathering and volcanic emission cessation are each invoked to explain the drawdown of pCO2. To better constrain the oceanic role in carbon sequestration over the Middle Miocene detailed records of carbonate chemistry are needed. We present high resolution Boron/Calcium (B/Ca) and δ13C records in planktonic foraminifer T.trilobus spanning 12-17 Ma at ODP 761 (tropical eastern Indian Ocean) to document changes in surface ocean carbonate chemistry. An overall 30% increase in B/Ca ratios is expressed as two stepwise phases occurring at 14.7 and 13 Ma. Cyclic B/Ca variations are coherent with complimentary δ13C records suggesting a tight coupling between ocean carbonate chemistry parameters. Lower resolution B/Ca data at DSDP 588 (Pacific) and ODP 926 (Atlantic) corroborate the trends observed at ODP 761. We employ a paired approach that combines B/Ca (this study) to δ11B (Foster et al., 2012) and an ad hoc calibration to estimate changes in surface ocean dissolved inorganic carbon (DIC). We estimate a substantial decrease in surface ocean DIC spanning the Middle Miocene that culminates with modern day like values. This gradual decline in surface ocean DIC is coeval with existing deep-ocean records which together suggests a whole ocean reduction in carbon storage. We speculate that enhanced weathering

  9. Deterministic chaos at the ocean surface: applications and interpretations

    Directory of Open Access Journals (Sweden)

    A. J. Palmer

    1998-01-01

    Full Text Available Ocean surface, grazing-angle radar backscatter data from two separate experiments, one of which provided coincident time series of measured surface winds, were found to exhibit signatures of deterministic chaos. Evidence is presented that the lowest dimensional underlying dynamical system responsible for the radar backscatter chaos is that which governs the surface wind turbulence. Block-averaging time was found to be an important parameter for determining the degree of determinism in the data as measured by the correlation dimension, and by the performance of an artificial neural network in retrieving wind and stress from the radar returns, and in radar detection of an ocean internal wave. The correlation dimensions are lowered and the performance of the deterministic retrieval and detection algorithms are improved by averaging out the higher dimensional surface wave variability in the radar returns.

  10. Circulation of the surface waters in the north Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Varadachari, V.V.R.; Sharma, G.S.

    The circulation pattern of the surface waters in the North Indian Ocean for different months of the year is discussed. In order to arrive at a reliable and detailed picture of the circulation pattern, streamlines are drawn using the isogon technique...

  11. Auto-correlation analysis of ocean surface wind vectors

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    time series data of surface winds measured in situ by a deep water buoy in the Indian Ocean has been carried out. ... A case study using the TRMM Microwave Imager (TMI) and ... parameter is essential when the values of the parameter ...

  12. Phase spectral composition of wind generated ocean surface waves

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J.

    A study of the composition of the phase spectra of wind generated ocean surface waves is carried out using wave records collected employing a ship borne wave recorder. It is found that the raw phase spectral estimates could be fitted by the Uniform...

  13. Monitoring of ocean surface algal blooms in coastal and oceanic waters around India.

    Digital Repository Service at National Institute of Oceanography (India)

    Tholkapiyan, M.; Shanmugam, P.; Suresh, T.

    of the MODIS-Aqua-derived OSABI (ocean surface algal bloom index) and its seasonal composite images report new information and comprehensive pictures of these blooms and their evolution stages in a wide variety of events occurred at different times of the years...

  14. NOAA Climate Data Record (CDR) of Ocean Near Surface Atmospheric Properties, Version 2

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Ocean Surface Bundle (OSB) Climate Data Record (CDR) consist of three parts: sea surface temperature; near-surface wind speed, air temperature, and specific...

  15. Natural variability in the surface ocean carbonate ion concentration

    OpenAIRE

    N. S. Lovenduski; M. C. Long; K. Lindsay

    2015-01-01

    We investigate variability in the surface ocean carbonate ion concentration ([CO32−]) on the basis of a long control simulation with a fully-coupled Earth System Model. The simulation is run with a prescribed, pre-industrial atmospheric CO2 concentration for 1000 years, permitting investigation of natural [CO32−] variability on interannual to multi-decadal timescales. We find high interannual variability in surface [CO32−] in the tropical...

  16. Natural variability in the surface ocean carbonate ion concentration

    OpenAIRE

    Lovenduski, N. S.; Long, M. C.; Lindsay, K.

    2015-01-01

    We investigate variability in the surface ocean carbonate ion concentration ([CO32−]) on the basis of a~long control simulation with an Earth System Model. The simulation is run with a prescribed, pre-industrial atmospheric CO2 concentration for 1000 years, permitting investigation of natural [CO32−] variability on interannual to multi-decadal timescales. We find high interannual variability in surface [CO32−] in the tropical Pacific and ...

  17. Airborne Optical Remote Sensing of Ocean Surface Current Variability

    Science.gov (United States)

    Anderson, S. P.; Zuckerman, S.; Stuart, G.

    2016-02-01

    Accurate and timely knowledge of open ocean surface currents are needed for a variety of engineering and emergency missions, as well as for improving scientific understanding of ocean dynamics. This paper presents surface current observations from a new airborne current measurement capability called the Remote Ocean Current Imaging System (ROCIS). ROCIS exploits space-time processing of airborne ocean wave imagery to produce real-time maps of surface currents every 1 km along the flight track. Post-processing of the data allows for more in depth sensitivity studies than can be undertaken with the real-time measurements alone, providing swaths of current retrievals at higher spatial resolutions. Currents can be calculated on scales down to 100 m, across swaths 3 km wide, along the entire flight path. Here, we report on results for multiple ROCIS data collection flights over the Gulf of Mexico conducted in 2012, 2014 and 2015. We show comparisons to in situ current measurements, explore performance as a function of altitude, dwell, wind speed, and wave height, and discuss sources of error. We present examples of current retrievals revealing mesoscale and submesoscale variability. Lastly, we present horizontal kinetic energy spectra from select flights covering a range of spatial scales from hundreds of meters to hundreds of kilometers.

  18. Local pH at the surface of hen egg white lysozyme

    Science.gov (United States)

    Otosu, Takuhiro; Kobayashi, Kaito; Yamaguchi, Shoichi

    2018-02-01

    The microenvironment at the surface of hen-egg-white lysozyme (HEWL) was examined by analyzing the change in pKa of fluorescein isothiocyanate (FITC) upon binding to the N-terminus of HEWL. The result showed that the local pH at the HEWL surface is higher than the bulk pH. Furthermore, the data showed that the difference between the local and bulk pH becomes larger with decreasing pH, suggesting HEWL repels more protons at lower pH. Because the local pH affects the protonation states of functional amino-acids at the protein surface, the results provide the fundamental insight into the microenvironment at the protein surface.

  19. Clinical Study Monitoring the pH on Tooth Surfaces in Patients with and without Erosion

    OpenAIRE

    Lussi, Adrian; von Salis-Marincek, Maya; Ganss, Carolina; Hellwig, Elmar; Cheaib, Zeinab; Jaeggi, Thomas

    2012-01-01

    The aim of this study was to compare tooth surface pH after drinking orange juice or water in 39 patients with dental erosion and in 17 controls. The following investigations were carried out: measurement of pH values on selected tooth surfaces after ingestion of orange juice followed by ingestion of water (acid clearance), measurement of salivary flow rate and buffering capacity. Compared with the controls, patients with erosion showed significantly greater decreases in pH after drinking ora...

  20. The impact of low pH, low aragonite saturation state on calcifying corals: an in-situ study of ocean acidification from the "ojos" of Puerto Morelos, Mexico

    Science.gov (United States)

    Crook, E. D.; Paytan, A.; Potts, D. C.; Hernandez Terrones, L.; Rebolledo-Vieyra, M.

    2010-12-01

    Recent increases in atmospheric carbon dioxide have resulted in rising aqueous CO2 concentrations that lower the pH of the oceans (Caldeira and Wickett 2003, 2005, Doney et al., 2009). It is estimated that over the next 100 years, the pH of the surface oceans will decrease by ~0.4 pH units (Orr et al., 2005), which is expected to hinder the calcifying capabilities of numerous marine organisms. Previous field work (Hall-Spencer et al., 2008) indicates that ocean acidification will negatively impact calcifying species; however, to date, very little is known about the long-term impacts of ocean acidification from the in-situ study of coral reef ecosystems. The Yucatán Peninsula of Quintana Roo, Mexico, represents an ecosystem where naturally low pH groundwater (7.14-8.07) has been discharging offshore at highly localized points (called ojos) for millennia. We present preliminary chemical and biological data on a selection of ojos from lagoon sites in Puerto Morelos, Mexico. Our findings indicate a decrease in species richness and size with proximity to the low pH waters. We address the potential long-term implications of low pH, low aragonite saturation state on coral reef ecosystems.

  1. Microwave Remote Sensing Modeling of Ocean Surface Salinity and Winds Using an Empirical Sea Surface Spectrum

    Science.gov (United States)

    Yueh, Simon H.

    2004-01-01

    Active and passive microwave remote sensing techniques have been investigated for the remote sensing of ocean surface wind and salinity. We revised an ocean surface spectrum using the CMOD-5 geophysical model function (GMF) for the European Remote Sensing (ERS) C-band scatterometer and the Ku-band GMF for the NASA SeaWinds scatterometer. The predictions of microwave brightness temperatures from this model agree well with satellite, aircraft and tower-based microwave radiometer data. This suggests that the impact of surface roughness on microwave brightness temperatures and radar scattering coefficients of sea surfaces can be consistently characterized by a roughness spectrum, providing physical basis for using combined active and passive remote sensing techniques for ocean surface wind and salinity remote sensing.

  2. Intraseasonal sea surface warming in the western Indian Ocean by oceanic equatorial Rossby waves

    Science.gov (United States)

    2017-05-09

    USA, 2Naval Research Laboratory, Ocean Dynamics and Prediction Branch, Stennis Space Center, Hancock County, Mississippi, USA, 3Department of Physics ...IO and predominantly located south of the equator. The intraseasonal currents associated with downwelling ER waves act on the temperature gradient to...yield warm anomalies in the western IO, even in the presence of cooling by surface fluxes. The SST gradient is unique to the western IO and likely

  3. Potential controls of isoprene in the surface ocean

    Science.gov (United States)

    Hackenberg, S. C.; Andrews, S. J.; Airs, R.; Arnold, S. R.; Bouman, H. A.; Brewin, R. J. W.; Chance, R. J.; Cummings, D.; Dall'Olmo, G.; Lewis, A. C.; Minaeian, J. K.; Reifel, K. M.; Small, A.; Tarran, G. A.; Tilstone, G. H.; Carpenter, L. J.

    2017-04-01

    Isoprene surface ocean concentrations and vertical distribution, atmospheric mixing ratios, and calculated sea-to-air fluxes spanning approximately 125° of latitude (80°N-45°S) over the Arctic and Atlantic Oceans are reported. Oceanic isoprene concentrations were associated with a number of concurrently monitored biological variables including chlorophyll a (Chl a), photoprotective pigments, integrated primary production (intPP), and cyanobacterial cell counts, with higher isoprene concentrations relative to all respective variables found at sea surface temperatures greater than 20°C. The correlation between isoprene and the sum of photoprotective carotenoids, which is reported here for the first time, was the most consistent across all cruises. Parameterizations based on linear regression analyses of these relationships perform well for Arctic and Atlantic data, producing a better fit to observations than an existing Chl a-based parameterization. Global extrapolation of isoprene surface water concentrations using satellite-derived Chl a and intPP reproduced general trends in the in situ data and absolute values within a factor of 2 between 60% and 85%, depending on the data set and algorithm used.

  4. Constraining the climate and ocean pH of the early Earth with a geological carbon cycle model

    Science.gov (United States)

    Krissansen-Totton, Joshua; Arney, Giada N.; Catling, David C.

    2018-04-01

    The early Earth’s environment is controversial. Climatic estimates range from hot to glacial, and inferred marine pH spans strongly alkaline to acidic. Better understanding of early climate and ocean chemistry would improve our knowledge of the origin of life and its coevolution with the environment. Here, we use a geological carbon cycle model with ocean chemistry to calculate self-consistent histories of climate and ocean pH. Our carbon cycle model includes an empirically justified temperature and pH dependence of seafloor weathering, allowing the relative importance of continental and seafloor weathering to be evaluated. We find that the Archean climate was likely temperate (0–50 °C) due to the combined negative feedbacks of continental and seafloor weathering. Ocean pH evolves monotonically from 6.6‑0.4+0.6 (2σ) at 4.0 Ga to 7.0‑0.5+0.7 (2σ) at the Archean–Proterozoic boundary, and to 7.9‑0.2+0.1 (2σ) at the Proterozoic–Phanerozoic boundary. This evolution is driven by the secular decline of pCO2, which in turn is a consequence of increasing solar luminosity, but is moderated by carbonate alkalinity delivered from continental and seafloor weathering. Archean seafloor weathering may have been a comparable carbon sink to continental weathering, but is less dominant than previously assumed, and would not have induced global glaciation. We show how these conclusions are robust to a wide range of scenarios for continental growth, internal heat flow evolution and outgassing history, greenhouse gas abundances, and changes in the biotic enhancement of weathering.

  5. Constraining the climate and ocean pH of the early Earth with a geological carbon cycle model.

    Science.gov (United States)

    Krissansen-Totton, Joshua; Arney, Giada N; Catling, David C

    2018-04-17

    The early Earth's environment is controversial. Climatic estimates range from hot to glacial, and inferred marine pH spans strongly alkaline to acidic. Better understanding of early climate and ocean chemistry would improve our knowledge of the origin of life and its coevolution with the environment. Here, we use a geological carbon cycle model with ocean chemistry to calculate self-consistent histories of climate and ocean pH. Our carbon cycle model includes an empirically justified temperature and pH dependence of seafloor weathering, allowing the relative importance of continental and seafloor weathering to be evaluated. We find that the Archean climate was likely temperate (0-50 °C) due to the combined negative feedbacks of continental and seafloor weathering. Ocean pH evolves monotonically from [Formula: see text] (2σ) at 4.0 Ga to [Formula: see text] (2σ) at the Archean-Proterozoic boundary, and to [Formula: see text] (2σ) at the Proterozoic-Phanerozoic boundary. This evolution is driven by the secular decline of pCO 2 , which in turn is a consequence of increasing solar luminosity, but is moderated by carbonate alkalinity delivered from continental and seafloor weathering. Archean seafloor weathering may have been a comparable carbon sink to continental weathering, but is less dominant than previously assumed, and would not have induced global glaciation. We show how these conclusions are robust to a wide range of scenarios for continental growth, internal heat flow evolution and outgassing history, greenhouse gas abundances, and changes in the biotic enhancement of weathering. Copyright © 2018 the Author(s). Published by PNAS.

  6. Macroalgae may mitigate ocean acidification effects on mussel calcification by increasing pH and its fluctuations

    KAUST Repository

    Wahl, M.; Schneider Covachã , S.; Saderne, Vincent; Hiebenthal, C.; Mü ller, J. D.; Pansch, C.; Sawall, Y.

    2017-01-01

    Ocean acidification (OA) is generally assumed to negatively impact calcification rates of marine organisms. At a local scale however, biological activity of macrophytes may generate pH fluctuations with rates of change that are orders of magnitude larger than the long-term trend predicted for the open ocean. These fluctuations may in turn impact benthic calcifiers in the vicinity. Combining laboratory, mesocosm and field studies, such interactions between OA, the brown alga Fucus vesiculosus, the sea grass Zostera marina and the blue mussel Mytilus edulis were investigated at spatial scales from decimetres to 100s of meters in the western Baltic. Macrophytes increased the overall mean pH of the habitat by up to 0.3 units relative to macrophyte-free, but otherwise similar, habitats and imposed diurnal pH fluctuations with amplitudes ranging from 0.3 to more than 1 pH unit. These amplitudes and their impact on mussel calcification tended to increase with increasing macrophyte biomass to bulk water ratio. At the laboratory and mesocosm scales, biogenic pH fluctuations allowed mussels to maintain calcification even under acidified conditions by shifting most of their calcification activity into the daytime when biogenic fluctuations caused by macrophyte activity offered temporal refuge from OA stress. In natural habitats with a low biomass to water body ratio, the impact of biogenic pH fluctuations on mean calcification rates of M. edulis was less pronounced. Thus, in dense algae or seagrass habitats, macrophytes may mitigate OA impact on mussel calcification by raising mean pH and providing temporal refuge from acidification stress.

  7. Macroalgae may mitigate ocean acidification effects on mussel calcification by increasing pH and its fluctuations

    KAUST Repository

    Wahl, M.

    2017-06-26

    Ocean acidification (OA) is generally assumed to negatively impact calcification rates of marine organisms. At a local scale however, biological activity of macrophytes may generate pH fluctuations with rates of change that are orders of magnitude larger than the long-term trend predicted for the open ocean. These fluctuations may in turn impact benthic calcifiers in the vicinity. Combining laboratory, mesocosm and field studies, such interactions between OA, the brown alga Fucus vesiculosus, the sea grass Zostera marina and the blue mussel Mytilus edulis were investigated at spatial scales from decimetres to 100s of meters in the western Baltic. Macrophytes increased the overall mean pH of the habitat by up to 0.3 units relative to macrophyte-free, but otherwise similar, habitats and imposed diurnal pH fluctuations with amplitudes ranging from 0.3 to more than 1 pH unit. These amplitudes and their impact on mussel calcification tended to increase with increasing macrophyte biomass to bulk water ratio. At the laboratory and mesocosm scales, biogenic pH fluctuations allowed mussels to maintain calcification even under acidified conditions by shifting most of their calcification activity into the daytime when biogenic fluctuations caused by macrophyte activity offered temporal refuge from OA stress. In natural habitats with a low biomass to water body ratio, the impact of biogenic pH fluctuations on mean calcification rates of M. edulis was less pronounced. Thus, in dense algae or seagrass habitats, macrophytes may mitigate OA impact on mussel calcification by raising mean pH and providing temporal refuge from acidification stress.

  8. Community production modulates coral reef pH and the sensitivity of ecosystem calcification to ocean acidification

    Science.gov (United States)

    DeCarlo, Thomas M.; Cohen, Anne L.; Wong, George T. F.; Shiah, Fuh-Kwo; Lentz, Steven J.; Davis, Kristen A.; Shamberger, Kathryn E. F.; Lohmann, Pat

    2017-01-01

    Coral reefs are built of calcium carbonate (CaCO3) produced biogenically by a diversity of calcifying plants, animals, and microbes. As the ocean warms and acidifies, there is mounting concern that declining calcification rates could shift coral reef CaCO3 budgets from net accretion to net dissolution. We quantified net ecosystem calcification (NEC) and production (NEP) on Dongsha Atoll, northern South China Sea, over a 2 week period that included a transient bleaching event. Peak daytime pH on the wide, shallow reef flat during the nonbleaching period was ˜8.5, significantly elevated above that of the surrounding open ocean (˜8.0-8.1) as a consequence of daytime NEP (up to 112 mmol C m-2 h-1). Diurnal-averaged NEC was 390 ± 90 mmol CaCO3 m-2 d-1, higher than any other coral reef studied to date despite comparable calcifier cover (25%) and relatively high fleshy algal cover (19%). Coral bleaching linked to elevated temperatures significantly reduced daytime NEP by 29 mmol C m-2 h-1. pH on the reef flat declined by 0.2 units, causing a 40% reduction in NEC in the absence of pH changes in the surrounding open ocean. Our findings highlight the interactive relationship between carbonate chemistry of coral reef ecosystems and ecosystem production and calcification rates, which are in turn impacted by ocean warming. As open-ocean waters bathing coral reefs warm and acidify over the 21st century, the health and composition of reef benthic communities will play a major role in determining on-reef conditions that will in turn dictate the ecosystem response to climate change.

  9. Global biogeography of Prochlorococcus genome diversity in the surface ocean.

    Science.gov (United States)

    Kent, Alyssa G; Dupont, Chris L; Yooseph, Shibu; Martiny, Adam C

    2016-08-01

    Prochlorococcus, the smallest known photosynthetic bacterium, is abundant in the ocean's surface layer despite large variation in environmental conditions. There are several genetically divergent lineages within Prochlorococcus and superimposed on this phylogenetic diversity is extensive gene gain and loss. The environmental role in shaping the global ocean distribution of genome diversity in Prochlorococcus is largely unknown, particularly in a framework that considers the vertical and lateral mechanisms of evolution. Here we show that Prochlorococcus field populations from a global circumnavigation harbor extensive genome diversity across the surface ocean, but this diversity is not randomly distributed. We observed a significant correspondence between phylogenetic and gene content diversity, including regional differences in both phylogenetic composition and gene content that were related to environmental factors. Several gene families were strongly associated with specific regions and environmental factors, including the identification of a set of genes related to lower nutrient and temperature regions. Metagenomic assemblies of natural Prochlorococcus genomes reinforced this association by providing linkage of genes across genomic backbones. Overall, our results show that the phylogeography in Prochlorococcus taxonomy is echoed in its genome content. Thus environmental variation shapes the functional capabilities and associated ecosystem role of the globally abundant Prochlorococcus.

  10. Evaluation of Scaling Approaches for the Oceanic Dissipation Rate of Turbulent Kinetic Energy in the Surface Ocean

    Science.gov (United States)

    Esters, L. T.; Ward, B.; Sutherland, G.; Ten Doeschate, A.; Landwehr, S.; Bell, T. G.; Christensen, K. H.

    2016-02-01

    The air-sea exchange of heat, gas and momentum plays an important role for the Earth's weather and global climate. The exchange processes between ocean and atmosphere are influenced by the prevailing surface ocean dynamics. This surface ocean is a highly turbulent region where there is enhanced production of turbulent kinetic energy (TKE). The dissipation rate of TKE (ɛ) in the surface ocean is an important process for governing the depth of both the mixing and mixed layers, which are important length-scales for many aspects of ocean research. However, there exist very limited observations of ɛ under open ocean conditions and consequently our understanding of how to model the dissipation profile is very limited. The approaches to model profiles of ɛ that exist, differ by orders of magnitude depending on their underlying theoretical assumption and included physical processes. Therefore, scaling ɛ is not straight forward and requires open ocean measurements of ɛ to validate the respective scaling laws. This validated scaling of ɛ, is for example required to produce accurate mixed layer depths in global climate models. Errors in the depth of the ocean surface boundary layer can lead to biases in sea surface temperature. Here, we present open ocean measurements of ɛ from the Air-Sea Interaction Profiler (ASIP) collected during several cruises in different ocean basins. ASIP is an autonomous upwardly rising microstructure profiler allowing undisturbed profiling up to the ocean surface. These direct measurements of ɛ under various types of atmospheric and oceanic conditions along with measurements of atmospheric fluxes and wave conditions allow us to make a unique assessment of several scaling approaches based on wind, wave and buoyancy forcing. This will allow us to best assess the most appropriate ɛ-based parameterisation for air-sea exchange.

  11. Contrasting self-aggregation over land and ocean surfaces

    Science.gov (United States)

    Inda Diaz, H. A.; O'Brien, T. A.

    2017-12-01

    The spontaneous organization of convection into clusters, or self-aggregation, demonstrably changes the nature and statistics of precipitation. While there has been much recent progress in this area, the processes that control self-aggregation are still poorly understood. Most of the work to date has focused on self-aggregation over ocean-like surfaces, but it is particularly pressing to understand what controls convective aggregation over land, since the associated change in precipitation statistics—between non-aggregated and aggregated convection—could have huge impacts on society and infrastructure. Radiative-convective equilibrium (RCE), has been extensively used as an idealized framework to study the tropical atmosphere. Self-aggregation manifests in numerous numerical models of RCE, nevertheless, there is still a lack of understanding in how it relates to convective organization in the observed world. Numerous studies have examined self-aggregation using idealized Cloud Resolving Models (CRMs) and General Circulation Models over the ocean, however very little work has been done on RCE and self-aggregation over land. Idealized models of RCE over ocean have shown that aggregation is sensitive to sea surface temperature (SST), more intense precipitation occurs in aggregated systems, and a variety of feedbacks—such as surface flux, cloud radiative, and upgradient moisture transport— contribute to the maintenance of aggregation, however it is not clear if these results apply over land. Progress in this area could help relate understanding of self-aggregation in idealized simulations to observations. In order to explore the behavior of self-aggregation over land, we use a CRM to simulate idealized RCE over land. In particular, we examine the aggregation of convection and how it compares with aggregation over ocean. Based on previous studies, where a variety of different CRMs exhibit a SST threshold below which self-aggregation does not occur, we hypothesize

  12. Arctic Ocean surface geostrophic circulation 2003–2014

    Directory of Open Access Journals (Sweden)

    T. W. K. Armitage

    2017-07-01

    Full Text Available Monitoring the surface circulation of the ice-covered Arctic Ocean is generally limited in space, time or both. We present a new 12-year record of geostrophic currents at monthly resolution in the ice-covered and ice-free Arctic Ocean derived from satellite radar altimetry and characterise their seasonal to decadal variability from 2003 to 2014, a period of rapid environmental change in the Arctic. Geostrophic currents around the Arctic basin increased in the late 2000s, with the largest increases observed in summer. Currents in the southeastern Beaufort Gyre accelerated in late 2007 with higher current speeds sustained until 2011, after which they decreased to speeds representative of the period 2003–2006. The strength of the northwestward current in the southwest Beaufort Gyre more than doubled between 2003 and 2014. This pattern of changing currents is linked to shifting of the gyre circulation to the northwest during the time period. The Beaufort Gyre circulation and Fram Strait current are strongest in winter, modulated by the seasonal strength of the atmospheric circulation. We find high eddy kinetic energy (EKE congruent with features of the seafloor bathymetry that are greater in winter than summer, and estimates of EKE and eddy diffusivity in the Beaufort Sea are consistent with those predicted from theoretical considerations. The variability of Arctic Ocean geostrophic circulation highlights the interplay between seasonally variable atmospheric forcing and ice conditions, on a backdrop of long-term changes to the Arctic sea ice–ocean system. Studies point to various mechanisms influencing the observed increase in Arctic Ocean surface stress, and hence geostrophic currents, in the 2000s – e.g. decreased ice concentration/thickness, changing atmospheric forcing, changing ice pack morphology; however, more work is needed to refine the representation of atmosphere–ice–ocean coupling in models before we can fully

  13. Near-surface eddy dynamics in the Southern Ocean

    Directory of Open Access Journals (Sweden)

    Marilisa Trani

    2011-12-01

    Full Text Available The Antarctic Circumpolar Current (ACC is a crucial component of the global ocean conveyor belt, acting as a zonal link among the major ocean basins but, to some extent, limiting meridional exchange and tending to isolate the ocean south of it from momentum and heat income. In this work we investigate one of the most important mechanisms contributing to the poleward transfer of properties in the Southern Ocean, that is the eddy component of the dynamics. For this particular purpose, observations obtained from near-surface drifters have been used: they represent a very useful data set to analyse the eddy field because of their ability to catch a large number of scales of motion while providing a quasi-synoptic coverage of the investigated area. Estimates of the eddy heat and momentum fluxes are carried out using data taken from the Global Drifter Program databank; they refer to Surface Velocity Program drifter trajectories collected in the area south of 35°S between 1995 and 2006. Eddy kinetic energies, variance ellipses, momentum and heat fluxes have been calculated using the pseudo-Eulerian method, showing patterns in good agreement with those present in the literature based on observational and model data, although there are some quantitative differences. The eddy fluxes have been separated into their rotational and divergent portions, the latter being responsible for the meridional transports. The associated zonal and depth-exponentially integrated meridional heat transport exhibits values spanning over a range between -0.4 PW and –1.1 PW in the ACC region, consistent with previous estimates.

  14. Surface pH controls purple-to-blue transition of bacteriorhodopsin. A theoretical model of purple membrane surface

    OpenAIRE

    Szundi, I.; Stoeckenius, W.

    1989-01-01

    We have developed a surface model of purple membrane and applied it in an analysis of the purple-to-blue color change of bacteriorhodopsin which is induced by acidification or deionization. The model is based on dissociation and double layer theory and the known membrane structure. We calculated surface pH, ion concentrations, charge density, and potential as a function of bulk pH and concentration of mono- and divalent cations. At low salt concentrations, the surface pH is significantly lowe...

  15. Narrow pH Range of Surface Water Bodies Receiving Pesticide Input in Europe.

    Science.gov (United States)

    Bundschuh, Mirco; Weyers, Arnd; Ebeling, Markus; Elsaesser, David; Schulz, Ralf

    2016-01-01

    Fate and toxicity of the active ingredients (AI's) of plant protection products in surface waters is often influenced by pH. Although a general range of pH values is reported in literature, an evaluation targeting aquatic ecosystems with documented AI inputs is lacking at the larger scale. Results show 95% of European surface waters (n = 3075) with a documented history of AI exposure fall within a rather narrow pH range, between 7.0 and 8.5. Spatial and temporal variability in the data may at least be partly explained by the calcareous characteristics of parental rock material, the affiliation of the sampling site to a freshwater ecoregion, and the photosynthetic activity of macrophytes (i.e., higher pH values with photosynthesis). Nonetheless, the documented pH range fits well with the standard pH of most ecotoxicological test guidelines, confirming the fate and ecotoxicity of AIs are usually adequately addressed.

  16. The validation of ocean surface heat fluxes in AMIP

    International Nuclear Information System (INIS)

    Gleckler, P.J.; Randall, D.A.

    1993-09-01

    Recent intercomparisons of Atmospheric General Circulation Models (AGCMS) constrained with sea-surface temperatures have shown that while there are substantial differences among various models (with each other and available observations), overall the differences between them have been decreasing. The primary goal of AMIP is to enable a systematic intercomparison and validation of state-of-the- art AGCMs by supporting in-depth diagnosis of and interpretation of the model results. Official AMIP simulations are 10 years long, using monthly mean Sea-Surface Temperatures (SSTs) and sea ice conditions which are representative of the 1979--1988 decade. Some model properties are also dictated by the design of AMIP such as the solar constant, the atmospheric CO 2 concentration, and the approximate horizontal resolution. In this paper, some of the preliminary results of AMIP Subproject No. 5 will be summarized. The focus will be on the intercomparison and validation of ocean surface heat fluxes of the AMIP simulations available thus far

  17. Sea surface temperature and salinity from the Global Ocean Surface Underway Data (GOSUD) from 1980-01-03 to present

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This collection contains the Global Ocean Surface Underway Data (GOSUD) from 1980-01-03 to present as submitted to NOAA/NCEI. The data includes information about sea...

  18. Satellite Remote Sensing of Ocean Winds, Surface Waves and Surface Currents during the Hurricanes

    Science.gov (United States)

    Zhang, G.; Perrie, W. A.; Liu, G.; Zhang, L.

    2017-12-01

    Hurricanes over the ocean have been observed by spaceborne aperture radar (SAR) since the first SAR images were available in 1978. SAR has high spatial resolution (about 1 km), relatively large coverage and capability for observations during almost all-weather, day-and-night conditions. In this study, seven C-band RADARSAT-2 dual-polarized (VV and VH) ScanSAR wide images from the Canadian Space Agency (CSA) Hurricane Watch Program in 2017 are collected over five hurricanes: Harvey, Irma, Maria, Nate, and Ophelia. We retrieve the ocean winds by applying our C-band Cross-Polarization Coupled-Parameters Ocean (C-3PO) wind retrieval model [Zhang et al., 2017, IEEE TGRS] to the SAR images. Ocean waves are estimated by applying a relationship based on the fetch- and duration-limited nature of wave growth inside hurricanes [Hwang et al., 2016; 2017, J. Phys. Ocean.]. We estimate the ocean surface currents using the Doppler Shift extracted from VV-polarized SAR images [Kang et al., 2016, IEEE TGRS]. C-3PO model is based on theoretical analysis of ocean surface waves and SAR microwave backscatter. Based on the retrieved ocean winds, we estimate the hurricane center locations, maxima wind speeds, and radii of the five hurricanes by adopting the SHEW model (Symmetric Hurricane Estimates for Wind) by Zhang et al. [2017, IEEE TGRS]. Thus, we investigate possible relations between hurricane structures and intensities, and especially some possible effects of the asymmetrical characteristics on changes in the hurricane intensities, such as the eyewall replacement cycle. The three SAR images of Ophelia include the north coast of Ireland and east coast of Scotland allowing study of ocean surface currents respond to the hurricane. A system of methods capable of observing marine winds, surface waves, and surface currents from satellites is of value, even if these data are only available in near real-time or from SAR-related satellite images. Insight into high resolution ocean winds

  19. SWOT, The Surface Water and Ocean Topography Satellite Mission (Invited)

    Science.gov (United States)

    Alsdorf, D.; Andreadis, K.; Bates, P. D.; Biancamaria, S.; Clark, E.; Durand, M. T.; Fu, L.; Lee, H.; Lettenmaier, D. P.; Mognard, N. M.; Moller, D.; Morrow, R. A.; Rodriguez, E.; Shum, C.

    2009-12-01

    Surface fresh water is essential for life, yet we have surprisingly poor knowledge of its variability in space and time. Similarly, ocean circulation fundamentally drives global climate variability, yet the ocean current and eddy field that affects ocean circulation and heat transport at the sub-mesoscale resolution and particularly near coastal and estuary regions, is poorly known. About 50% of the vertical exchange of water properties (nutrients, dissovled CO2, heat, etc) in the upper ocean is taking place at the sub-mesoscale. Measurements from the Surface Water and Ocean Topography satellite mission (SWOT) will make strides in understanding these processes and improving global ocean models for studying climate change. SWOT is a swath-based interferometric-altimeter designed to acquire elevations of ocean and terrestrial water surfaces at unprecedented spatial and temporal resolutions. The mission will provide measurements of storage changes in lakes, reservoirs, and wetlands as well as estimates of discharge in rivers. These measurements are important for global water and energy budgets, constraining hydrodynamic models of floods, carbon evasion through wetlands, and water management, especially in developing nations. Perhaps most importantly, SWOT measurements will provide a fundamental understanding of the spatial and temporal variations in global surface waters, which for many countries are the primary source of water. An on-going effort, the “virtual mission” (VM) is designed to help constrain the required height and slope accuracies, the spatial sampling (both pixels and orbital coverage), and the trade-offs in various temporal revisits. Example results include the following: (1) Ensemble Kalman filtering of VM simulations recover water depth and discharge, reducing the discharge RMSE from 23.2% to 10.0% over an 84-day simulation period, relative to a simulation without assimilation. (2) Ensemble-based data assimilation of SWOT like measurements yields

  20. Surface pH controls purple-to-blue transition of bacteriorhodopsin. A theoretical model of purple membrane surface.

    Science.gov (United States)

    Szundi, I; Stoeckenius, W

    1989-08-01

    We have developed a surface model of purple membrane and applied it in an analysis of the purple-to-blue color change of bacteriorhodopsin which is induced by acidification or deionization. The model is based on dissociation and double layer theory and the known membrane structure. We calculated surface pH, ion concentrations, charge density, and potential as a function of bulk pH and concentration of mono- and divalent cations. At low salt concentrations, the surface pH is significantly lower than the bulk pH and it becomes independent of bulk pH in the deionized membrane suspension. Using an experimental acid titration curve for neutral, lipid-depleted membrane, we converted surface pH into absorption values. The calculated bacteriohodopsin color changes for acidification of purple, and titrations of deionized blue membrane with cations or base agree well with experimental results. No chemical binding is required to reproduce the experimental curves. Surface charge and potential changes in acid, base and cation titrations are calculated and their relation to the color change is discussed. Consistent with structural data, 10 primary phosphate and two basic surface groups per bacteriorhodopsin are sufficient to obtain good agreement between all calculated and experimental curves. The results provide a theoretical basis for our earlier conclusion that the purple-to-blue transition must be attributed to surface phenomena and not to cation binding at specific sites in the protein.

  1. Visible-infrared remote-sensing model and applications for ocean waters. Ph.D. Thesis

    Science.gov (United States)

    Lee, Zhongping

    1994-01-01

    Remote sensing has become important in the ocean sciences, especially for research involving large spatial scales. To estimate the in-water constituents through remote sensing, whether carried out by satellite or airplane, the signal emitted from beneath the sea surface, the so called water-leaving radiance (L(w)), is of prime importance. The magnitude of L(w) depends on two terms: one is the intensity of the solar input, and the other is the reflectance of the in-water constituents. The ratio of the water-leaving radiance to the downwelling irradiance (E(d)) above the sear surface (remote-sensing reflectance, R(sub rs)) is independent of the intensity of the irradiance input, and is largely a function of the optical properties of the in-water constituents. In this work, a model is developed to interpret r(sub rs) for ocean water in the visible-infrared range. In addition to terms for the radiance scattered from molecules and particles, the model includes terms that describe contributions from bottom reflectance, fluorescence of gelbstoff or colored dissolved organic matter (CDOM), and water Raman scattering. By using this model, the measured R(sub rs) of waters from the West Florida Shelf to the Mississippi River plume, which covered a (concentration of chlorophyll a) range of 0.07 - 50 mg/cu m, were well interpreted. The average percentage difference (a.p.d.) between the measured and modeled R(sub rs) is 3.4%, and, for the shallow waters, the model-required water depth is within 10% of the chart depth. Simple mathematical simulations for the phytoplankton pigment absorption coefficient (a(sub theta)) are suggested for using the R(sub rs) model. The inverse problem of R(sub rs), which is to analytically derive the in-water constituents from R(sub rs) data alone, can be solved using the a(sub theta) functions without prior knowledge of the in-water optical properties. More importantly, this method avoids problems associated with a need for knowledge of the shape

  2. Diurnal variability of surface fluxes at an oceanic station in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, Y.V.B.; Rao, D.P.

    Diurnal variability of the surface fluxes and ocean heat content was studied using the time-series data on marine surface meteorological parameters and upper ocean temperature collected at an oceanic station in the Bay of Bengal during 1st to 8th...

  3. Climate change feedbacks on future oceanic acidification

    International Nuclear Information System (INIS)

    McNeil, Ben I.; Matear, Richard J.

    2007-01-01

    Oceanic anthropogenic CO 2 uptake will decrease both the pH and the aragonite saturation state (Oarag) of seawater leading to an oceanic acidification. However, the factors controlling future changes in pH and Oarag are independent and will respond differently to oceanic climate change feedbacks such as ocean warming, circulation and biological changes. We examine the sensitivity of these two CO 2 -related parameters to climate change feedbacks within a coupled atmosphere-ocean model. The ocean warming feedback was found to dominate the climate change responses in the surface ocean. Although surface pH is projected to decrease relatively uniformly by about 0.3 by the year 2100, we find pH to be insensitive to climate change feedbacks, whereas Oarag is buffered by ∼15%. Ocean carbonate chemistry creates a situation whereby the direct pH changes due to ocean warming are almost cancelled by the pH changes associated with dissolved inorganic carbon concentrations changes via a reduction in CO 2 solubility from ocean warming. We show that the small climate change feedback on future surface ocean pH is independent to the amount of ocean warming. Our analysis therefore implies that future projections of surface ocean acidification only need to consider future atmospheric CO 2 levels, not climate change induced modifications in the ocean

  4. A Genetically Encoded pH Sensor for Tracking Surface Proteins through Endocytosis**

    OpenAIRE

    Grover, Anmol; Schmidt, Brigitte F.; Salter, Russell D.; Watkins, Simon C.; Waggoner, Alan S.; Bruchez, Marcel P.

    2012-01-01

    We have combined our fluorogen activating peptide[1] with a new tandem dye molecule to develop a biosensor that labels a cell-surface protein and displays an easily detectable pH dependent emission color change by efficient intramolecular Förster resonant energy transfer. This probe has demonstrated pH variations in β2-adrenergic receptor trafficking and revealed a process of surface to endosome inter-cellular transfer in dendritic cells with potential significance in antigen transfer.

  5. Abiotic versus biotic drivers of ocean pH variation under fast sea ice in McMurdo Sound, Antarctica.

    Science.gov (United States)

    Matson, Paul G; Washburn, Libe; Martz, Todd R; Hofmann, Gretchen E

    2014-01-01

    Ocean acidification is expected to have a major effect on the marine carbonate system over the next century, particularly in high latitude seas. Less appreciated is natural environmental variation within these systems, particularly in terms of pH, and how this natural variation may inform laboratory experiments. In this study, we deployed sensor-equipped moorings at 20 m depths at three locations in McMurdo Sound, comprising deep (bottom depth>200 m: Hut Point Peninsula) and shallow environments (bottom depth ∼25 m: Cape Evans and New Harbor). Our sensors recorded high-frequency variation in pH (Hut Point and Cape Evans only), tide (Cape Evans and New Harbor), and water mass properties (temperature and salinity) during spring and early summer 2011. These collective observations showed that (1) pH differed spatially both in terms of mean pH (Cape Evans: 8.009±0.015; Hut Point: 8.020±0.007) and range of pH (Cape Evans: 0.090; Hut Point: 0.036), and (2) pH was not related to the mixing of two water masses, suggesting that the observed pH variation is likely not driven by this abiotic process. Given the large daily fluctuation in pH at Cape Evans, we developed a simple mechanistic model to explore the potential for biotic processes--in this case algal photosynthesis--to increase pH by fixing carbon from the water column. For this model, we incorporated published photosynthetic parameters for the three dominant algal functional groups found at Cape Evans (benthic fleshy red macroalgae, crustose coralline algae, and sea ice algal communities) to estimate oxygen produced/carbon fixed from the water column underneath fast sea ice and the resulting pH change. These results suggest that biotic processes may be a primary driver of pH variation observed under fast sea ice at Cape Evans and potentially at other shallow sites in McMurdo Sound.

  6. Abiotic versus biotic drivers of ocean pH variation under fast sea ice in McMurdo Sound, Antarctica.

    Directory of Open Access Journals (Sweden)

    Paul G Matson

    Full Text Available Ocean acidification is expected to have a major effect on the marine carbonate system over the next century, particularly in high latitude seas. Less appreciated is natural environmental variation within these systems, particularly in terms of pH, and how this natural variation may inform laboratory experiments. In this study, we deployed sensor-equipped moorings at 20 m depths at three locations in McMurdo Sound, comprising deep (bottom depth>200 m: Hut Point Peninsula and shallow environments (bottom depth ∼25 m: Cape Evans and New Harbor. Our sensors recorded high-frequency variation in pH (Hut Point and Cape Evans only, tide (Cape Evans and New Harbor, and water mass properties (temperature and salinity during spring and early summer 2011. These collective observations showed that (1 pH differed spatially both in terms of mean pH (Cape Evans: 8.009±0.015; Hut Point: 8.020±0.007 and range of pH (Cape Evans: 0.090; Hut Point: 0.036, and (2 pH was not related to the mixing of two water masses, suggesting that the observed pH variation is likely not driven by this abiotic process. Given the large daily fluctuation in pH at Cape Evans, we developed a simple mechanistic model to explore the potential for biotic processes--in this case algal photosynthesis--to increase pH by fixing carbon from the water column. For this model, we incorporated published photosynthetic parameters for the three dominant algal functional groups found at Cape Evans (benthic fleshy red macroalgae, crustose coralline algae, and sea ice algal communities to estimate oxygen produced/carbon fixed from the water column underneath fast sea ice and the resulting pH change. These results suggest that biotic processes may be a primary driver of pH variation observed under fast sea ice at Cape Evans and potentially at other shallow sites in McMurdo Sound.

  7. Sea level: measuring the bounding surfaces of the ocean

    Science.gov (United States)

    Tamisiea, Mark E.; Hughes, Chris W.; Williams, Simon D. P.; Bingley, Richard M.

    2014-01-01

    The practical need to understand sea level along the coasts, such as for safe navigation given the spatially variable tides, has resulted in tide gauge observations having the distinction of being some of the longest instrumental ocean records. Archives of these records, along with geological constraints, have allowed us to identify the century-scale rise in global sea level. Additional data sources, particularly satellite altimetry missions, have helped us to better identify the rates and causes of sea-level rise and the mechanisms leading to spatial variability in the observed rates. Analysis of all of the data reveals the need for long-term and stable observation systems to assess accurately the regional changes as well as to improve our ability to estimate future changes in sea level. While information from many scientific disciplines is needed to understand sea-level change, this review focuses on contributions from geodesy and the role of the ocean's bounding surfaces: the sea surface and the Earth's crust. PMID:25157196

  8. Sea level: measuring the bounding surfaces of the ocean.

    Science.gov (United States)

    Tamisiea, Mark E; Hughes, Chris W; Williams, Simon D P; Bingley, Richard M

    2014-09-28

    The practical need to understand sea level along the coasts, such as for safe navigation given the spatially variable tides, has resulted in tide gauge observations having the distinction of being some of the longest instrumental ocean records. Archives of these records, along with geological constraints, have allowed us to identify the century-scale rise in global sea level. Additional data sources, particularly satellite altimetry missions, have helped us to better identify the rates and causes of sea-level rise and the mechanisms leading to spatial variability in the observed rates. Analysis of all of the data reveals the need for long-term and stable observation systems to assess accurately the regional changes as well as to improve our ability to estimate future changes in sea level. While information from many scientific disciplines is needed to understand sea-level change, this review focuses on contributions from geodesy and the role of the ocean's bounding surfaces: the sea surface and the Earth's crust. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  9. The Impacts of Daily Surface Forcing in the Upper Ocean over Tropical Pacific: A Numerical Study

    Science.gov (United States)

    Sui, C.-H.; Rienecker, Michele M.; Li, Xiaofan; Lau, William K.-M.; Laszlo, Istvan; Pinker, Rachel T.

    2001-01-01

    Tropical Pacific Ocean is an important region that affects global climate. How the ocean responds to the atmospheric surface forcing (surface radiative, heat and momentum fluxes) is a major topic in oceanographic research community. The ocean becomes warm when more heat flux puts into the ocean. The monthly mean forcing has been used in the past years since daily forcing was unavailable due to the lack of observations. The daily forcing is now available from the satellite measurements. This study investigates the response of the upper ocean over tropical Pacific to the daily atmospheric surface forcing. The ocean surface heat budgets are calculated to determine the important processes for the oceanic response. The differences of oceanic responses between the eastern and western Pacific are intensively discussed.

  10. Ocean Surface Topography Mission (OSTM) /Jason-3: Orbital Information, 2015- (NODC Accession 0122598)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Jason-3 is the fourth mission in U.S.-European series of satellite missions that measure the height of the ocean surface. Scheduled to launch in 2015, the mission...

  11. Ocean Surface Topography Mission (OSTM) /Jason-3: Telemetry, 2015- (NODC Accession 0122599)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Jason-3 is the fourth mission in U.S.-European series of satellite missions that measure the height of the ocean surface. Scheduled to launch in 2015, the mission...

  12. Ocean Surface Topography Mission (OSTM) /Jason-3: Auxiliary Files, 2015- (NODC Accession 0122597)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Jason-3 is the fourth mission in U.S.-European series of satellite missions that measure the height of the ocean surface. Scheduled to launch in 2015, the mission...

  13. Ocean Surface Topography Mission (OSTM) /Jason-3: Ancillary Files, 2015- (NCEI Accession 0122596)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Jason-3 is the fourth mission in U.S.-European series of satellite missions that measure the height of the ocean surface. Scheduled to launch in 2015, the mission...

  14. Surface Ocean CO2 Atlas Database Version 5 (SOCATv5) (NCEI Accession 0163180)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Surface Ocean CO2 Atlas (SOCAT, www.socat.info) is a synthesis activity by the international marine carbon research community and has more than 100 contributors...

  15. Baseline monitoring of the western Arctic Ocean estimates 20% of Canadian basin surface waters are undersaturated with respect to aragonite.

    Directory of Open Access Journals (Sweden)

    Lisa L Robbins

    Full Text Available Marine surface waters are being acidified due to uptake of anthropogenic carbon dioxide, resulting in surface ocean areas of undersaturation with respect to carbonate minerals, including aragonite. In the Arctic Ocean, acidification is expected to occur at an accelerated rate with respect to the global oceans, but a paucity of baseline data has limited our understanding of the extent of Arctic undersaturation and of regional variations in rates and causes. The lack of data has also hindered refinement of models aimed at projecting future trends of ocean acidification. Here, based on more than 34,000 data records collected in 2010 and 2011, we establish a baseline of inorganic carbon data (pH, total alkalinity, dissolved inorganic carbon, partial pressure of carbon dioxide, and aragonite saturation index for the western Arctic Ocean. This data set documents aragonite undersaturation in ≈ 20% of the surface waters of the combined Canada and Makarov basins, an area characterized by recent acceleration of sea ice loss. Conservative tracer studies using stable oxygen isotopic data from 307 sites show that while the entire surface of this area receives abundant freshwater from meteoric sources, freshwater from sea ice melt is most closely linked to the areas of carbonate mineral undersaturation. These data link the Arctic Ocean's largest area of aragonite undersaturation to sea ice melt and atmospheric CO2 absorption in areas of low buffering capacity. Some relatively supersaturated areas can be linked to localized biological activity. Collectively, these observations can be used to project trends of ocean acidification in higher latitude marine surface waters where inorganic carbon chemistry is largely influenced by sea ice meltwater.

  16. Molecular biogeochemical provinces in the Atlantic Surface Ocean

    Science.gov (United States)

    Koch, B. P.; Flerus, R.; Schmitt-Kopplin, P.; Lechtenfeld, O. J.; Bracher, A.; Cooper, W.; Frka, S.; Gašparović, B.; Gonsior, M.; Hertkorn, N.; Jaffe, R.; Jenkins, A.; Kuss, J.; Lara, R. J.; Lucio, M.; McCallister, S. L.; Neogi, S. B.; Pohl, C.; Roettgers, R.; Rohardt, G.; Schmitt, B. B.; Stuart, A.; Theis, A.; Ying, W.; Witt, M.; Xie, Z.; Yamashita, Y.; Zhang, L.; Zhu, Z. Y.; Kattner, G.

    2010-12-01

    One of the most important aspects to understand marine organic carbon fluxes is to resolve the molecular mechanisms which convert fresh, labile biomolecules into semi-labile and refractory dissolved and particulate organic compounds in the ocean. In this interdisciplinary project, which was performed on a cruise with RV Polarstern, we carried out a detailed molecular characterisation of dissolved organic matter (DOM) on a North-South transect in the Atlantic surface ocean in order to relate the data to different biological, climatic, oceanographic, and meteorological regimes as well as to terrestrial input from riverine and atmospheric sources. Our goal was to achieve a high resolution data set for the biogeochemical characterisation of the sources and reactivity of DOM. We applied ultrahigh resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS), nutrient, trace element, amino acid, and lipid analyses and other biogeochemical measurements for 220 samples from the upper water column (0-200m) and eight deep profiles. Various spectroscopic techniques were applied continuously in a constant sample water flow supplied by a fish system and the moon pool. Radiocarbon dating enabled assessing DOC residence time. Bacterial abundance and production provided a metabolic context for the DOM characterization work and pCO2 concentrations. Combining molecular organic techniques and inductively coupled plasma mass spectrometry (ICP-MS) established an important link between organic and inorganic biogeochemical studies. Multivariate statistics, primarily based on FT-ICR-MS data for 220 samples, allowed identifying geographical clusters which matched ecological provinces proposed previously by Longhurst (2007). Our study demonstrated that marine DOM carries molecular information reflecting the “history” of ocean water masses. This information can be used to define molecular biogeochemical provinces and to improve our understanding of element fluxes in

  17. Application of SMAP Data for Ocean Surface Remote Sensing

    Science.gov (United States)

    Fore, A.; Yueh, S. H.; Tang, W.; Stiles, B. W.; Hayashi, A.

    2017-12-01

    The Soil Moisture Active Passive (SMAP) mission was launched January 31st, 2015. It is designed to measure the soil moisture over land using a combined active / passive L-band system. Due to the Aquarius mission, L-band model functions for ocean winds and salinity are mature and are directly applicable to the SMAP mission. In contrast to Aquarius, the higher resolution and scanning geometry of SMAP allow for wide-swath ocean winds and salinities to be retrieved. In this talk we present the SMAP Sea Surface Salinity (SSS) and extreme winds dataset and its performance. First we discuss the heritage of SMAP SSS algorithms, showing that SMAP and Aquarius show excellent agreement in the ocean surface roughness correction. Then, we give an overview of some newly developed algorithms that are only relevant to the SMAP system; a new galaxy correction and land correction enabling SSS retrievals up to 40 km from coast. We discuss recent improvements to the SMAP data processing for version 4.0. Next we compare the performance of the SMAP SSS to in-situ salinity measurements obtained from ARGO floats, tropical moored buoys, and ship-based data. SMAP SSS has accuracy of 0.2 PSU on a monthly basis compared to ARGO gridded data in tropics and mid-latitudes. In tropical oceans, time series comparison of salinity measured at 1 m depth by moored buoys indicates SMAP can track large salinity changes within a month. Synergetic analysis of SMAP, SMOS, and Argo data allows us to identify and exclude erroneous buoy data from assessment of SMAP SSS. The resulting SMAP-buoy matchup analysis gives a mean standard deviation (STD) of 0.22 PSU and correlation of 0.73 on weekly scale; at monthly scale the mean STD decreased to 0.17 PSU and the correlation increased to 0.8. In addition to SSS, SMAP provides a view into tropical cyclones having much higher sensitivity than traditional scatterometers. We validate the high-winds using collocations with SFMR during tropical cyclones as well as

  18. Estimating the Ocean Flow Field from Combined Sea Surface Temperature and Sea Surface Height Data

    Science.gov (United States)

    Stammer, Detlef; Lindstrom, Eric (Technical Monitor)

    2002-01-01

    This project was part of a previous grant at MIT that was moved over to the Scripps Institution of Oceanography (SIO) together with the principal investigator. The final report provided here is concerned only with the work performed at SIO since January 2000. The primary focus of this project was the study of the three-dimensional, absolute and time-evolving general circulation of the global ocean from a combined analysis of remotely sensed fields of sea surface temperature (SST) and sea surface height (SSH). The synthesis of those two fields was performed with other relevant physical data, and appropriate dynamical ocean models with emphasis on constraining ocean general circulation models by a combination of both SST and SSH data. The central goal of the project was to improve our understanding and modeling of the relationship between the SST and its variability to internal ocean dynamics, and the overlying atmosphere, and to explore the relative roles of air-sea fluxes and internal ocean dynamics in establishing anomalies in SST on annual and longer time scales. An understanding of those problems will feed into the general discussion on how SST anomalies vary with time and the extend to which they interact with the atmosphere.

  19. On the interaction between ocean surface waves and seamounts

    Science.gov (United States)

    Sosa, Jeison; Cavaleri, Luigi; Portilla-Yandún, Jesús

    2017-12-01

    Of the many topographic features, more specifically seamounts, that are ubiquitous in the ocean floor, we focus our attention on those with relatively shallow summits that can interact with wind-generated surface waves. Among these, especially relatively long waves crossing the oceans (swells) and stormy seas are able to affect the water column up to a considerable depth and therefore interact with these deep-sea features. We quantify this interaction through numerical experiments using a numerical wave model (SWAN), in which a simply shaped seamount is exposed to waves of different length. The results show a strong interaction that leads to significant changes in the wave field, creating wake zones and regions of large wave amplification. This is then exemplified in a practical case where we analyze the interaction of more realistic sea conditions with a very shallow rock in the Yellow Sea. Potentially important for navigation and erosion processes, mutatis mutandis, these results are also indicative of possible interactions with emerged islands and sand banks in shelf seas.

  20. Volcanic ash as fertiliser for the surface ocean

    Directory of Open Access Journals (Sweden)

    B. Langmann

    2010-04-01

    Full Text Available Iron is a key limiting micro-nutrient for marine primary productivity. It can be supplied to the ocean by atmospheric dust deposition. Volcanic ash deposition into the ocean represents another external and so far largely neglected source of iron. This study demonstrates strong evidence for natural fertilisation in the iron-limited oceanic area of the NE Pacific, induced by volcanic ash from the eruption of Kasatochi volcano in August 2008. Atmospheric and oceanic conditions were favourable to generate a massive phytoplankton bloom in the NE Pacific Ocean which for the first time strongly suggests a connection between oceanic iron-fertilisation and volcanic ash supply.

  1. Reconciling surface ocean productivity, export fluxes and sediment composition in a global biogeochemical ocean model

    Directory of Open Access Journals (Sweden)

    M. Gehlen

    2006-01-01

    Full Text Available This study focuses on an improved representation of the biological soft tissue pump in the global three-dimensional biogeochemical ocean model PISCES. We compare three parameterizations of particle dynamics: (1 the model standard version including two particle size classes, aggregation-disaggregation and prescribed sinking speed; (2 an aggregation-disaggregation model with a particle size spectrum and prognostic sinking speed; (3 a mineral ballast parameterization with no size classes, but prognostic sinking speed. In addition, the model includes a description of surface sediments and organic carbon early diagenesis. Model output is compared to data or data based estimates of ocean productivity, pe-ratios, particle fluxes, surface sediment bulk composition and benthic O2 fluxes. Model results suggest that different processes control POC fluxes at different depths. In the wind mixed layer turbulent particle coagulation appears as key process in controlling pe-ratios. Parameterization (2 yields simulated pe-ratios that compare well to observations. Below the wind mixed layer, POC fluxes are most sensitive to the intensity of zooplankton flux feeding, indicating the importance of zooplankton community composition. All model parameters being kept constant, the capability of the model to reproduce yearly mean POC fluxes below 2000 m and benthic oxygen demand does at first order not dependent on the resolution of the particle size spectrum. Aggregate formation appears essential to initiate an intense biological pump. At great depth the reported close to constant particle fluxes are most likely the result of the combined effect of aggregate formation and mineral ballasting.

  2. Retrieval of sea surface air temperature from satellite data over Indian Ocean: An empirical approach

    Digital Repository Service at National Institute of Oceanography (India)

    Sathe, P.V.; Muraleedharan, P.M.

    the sea surface air temperature from satellite derived sea surface humidity in the Indian Ocean. Using the insitu data on surface met parameters collected on board O.R.V. Sagar Kanya in the Indian Ocean over a period of 15 years, the relationship between...

  3. Ocean Physicochemistry versus Climate Change

    OpenAIRE

    Góralski, Bogdan

    2014-01-01

    It is the dwindling ocean productivity which leaves dissolved carbon dioxide in the seawater. Its solubility is diminished by the rise in ocean water temperature (by one degree Celsius since 1910, according to IPCC). Excess carbon dioxide is emitted into the atmosphere, while its growing concentration in seawater leads to ocean acidification. Ocean acidification leading to lowering pH of surface ocean water remains an unsolved problem of science. My today’s lecture will mark an attempt at ...

  4. Regulation of arsenic mobility on basaltic glass surfaces by speciation and pH.

    Science.gov (United States)

    Sigfusson, Bergur; Meharg, Andrew A; Gislason, Sigurdur R

    2008-12-01

    The importance of geothermal energy as a source for electricity generation and district heating has increased over recent decades. Arsenic can be a significant constituent of the geothermal fluids pumped to the surface during power generation. Dissolved As exists in different oxidation states, mainly as As(III) and As(V), and the charge of individual species varies with pH. Basaltic glass is one of the most important rock types in many high-temperature geothermal fields. Static batch and dynamic column experiments were combined to generate and validate sorption coefficients for As(III) and As(V) in contact with basaltic glass at pH 3-10. Validation was carried out by two empirical kinetic models and a surface complexation model (SCM). The SCM provided a better fit to the experimental column data than kinetic models at high pH values. However, in certain circumstances, an adequate estimation of As transport in the column could not be attained without incorporation of kinetic reactions. The varying mobility with pH was due to the combined effects of the variable charge of the basaltic glass with the pH point of zero charge at 6.8 and the individual As species as pH shifted, respectively. The mobility of As(III) decreased with increasing pH. The opposite was true for As(V), being nearly immobile at pH 3 to being highly mobile at pH 10. Incorporation of appropriate sorption constants, based on the measured pH and Eh of geothermal fluids, into regional groundwater-flow models should allow prediction of the As(III) and As(V) transport from geothermal systems to adjacent drinking water sources and ecosystems.

  5. REGRESSION ANALYSIS OF SEA-SURFACE-TEMPERATURE PATTERNS FOR THE NORTH PACIFIC OCEAN.

    Science.gov (United States)

    SEA WATER, *SURFACE TEMPERATURE, *OCEANOGRAPHIC DATA, PACIFIC OCEAN, REGRESSION ANALYSIS , STATISTICAL ANALYSIS, UNDERWATER EQUIPMENT, DETECTION, UNDERWATER COMMUNICATIONS, DISTRIBUTION, THERMAL PROPERTIES, COMPUTERS.

  6. National Coral Reef Monitoring Program: Dissolved inorganic carbon, total alkalinity, pH and other variables collected from surface discrete observations using infrared dissolved inorganic carbon analyzer, alkalinity titrator and other instruments from the North Atlantic Ocean near Key West, Florida (Class III climate monitoring sites) from 2012-03-23 to 2014-12-11 (NCEI Accession 0132022)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains data collected to monitor changes to coral reef carbonate chemistry over time, at US affiliated coral reef sites, through quantifying...

  7. The causes of alkalinity variations in the global surface ocean

    OpenAIRE

    Fry, Claudia Helen

    2016-01-01

    Human activities have caused the atmospheric concentration of carbon dioxide (CO2) to increase by 120 ppmv from pre-industrial times to 2014. The ocean takes up approximately a quarter of the anthropogenic CO2, causing ocean acidification (OA). Therefore it is necessary to study the ocean carbonate system, including alkalinity, to quantify the flux of CO2 into the ocean and understand OA. Since the 1970s, carbonate system measurements have been undertaken which can be analyzed to quantify the...

  8. A cell-surface-anchored ratiometric fluorescent probe for extracellular pH sensing.

    Science.gov (United States)

    Ke, Guoliang; Zhu, Zhi; Wang, Wei; Zou, Yuan; Guan, Zhichao; Jia, Shasha; Zhang, Huimin; Wu, Xuemeng; Yang, Chaoyong James

    2014-09-10

    Accurate sensing of the extracellular pH is a very important yet challenging task in biological and clinical applications. This paper describes the development of an amphiphilic lipid-DNA molecule as a simple yet useful cell-surface-anchored ratiometric fluorescent probe for extracellular pH sensing. The lipid-DNA probe, which consists of a hydrophobic diacyllipid tail and a hydrophilic DNA strand, is modified with two fluorescent dyes; one is pH-sensitive as pH indicator and the other is pH-insensitive as an internal reference. The lipid-DNA probe showed sensitive and reversible response to pH change in the range of 6.0-8.0, which is suitable for most extracellular studies. In addition, based on simple hydrophobic interactions with the cell membrane, the lipid-DNA probe can be easily anchored on the cell surface with negligible cytotoxicity, excellent stability, and unique ratiometric readout, thus ensuring its accurate sensing of extracellular pH. Finally, this lipid-DNA-based ratiometric pH indicator was successfully used for extracellular pH sensing of cells in 3D culture environment, demonstrating the potential applications of the sensor in biological and medical studies.

  9. Metrological challenges for measurements of key climatological observables: oceanic salinity and pH, and atmospheric humidity. Part 1: overview

    Science.gov (United States)

    Feistel, R.; Wielgosz, R.; Bell, S. A.; Camões, M. F.; Cooper, J. R.; Dexter, P.; Dickson, A. G.; Fisicaro, P.; Harvey, A. H.; Heinonen, M.; Hellmuth, O.; Kretzschmar, H.-J.; Lovell-Smith, J. W.; McDougall, T. J.; Pawlowicz, R.; Ridout, P.; Seitz, S.; Spitzer, P.; Stoica, D.; Wolf, H.

    2016-02-01

    Water in its three ambient phases plays the central thermodynamic role in the terrestrial climate system. Clouds control Earth’s radiation balance, atmospheric water vapour is the strongest ‘greenhouse’ gas, and non-equilibrium relative humidity at the air-sea interface drives evaporation and latent heat export from the ocean. On climatic time scales, melting ice caps and regional deviations of the hydrological cycle result in changes of seawater salinity, which in turn may modify the global circulation of the oceans and their ability to store heat and to buffer anthropogenically produced carbon dioxide. In this paper, together with three companion articles, we examine the climatologically relevant quantities ocean salinity, seawater pH and atmospheric relative humidity, noting fundamental deficiencies in the definitions of those key observables, and their lack of secure foundation on the International System of Units, the SI. The metrological histories of those three quantities are reviewed, problems with their current definitions and measurement practices are analysed, and options for future improvements are discussed in conjunction with the recent seawater standard TEOS-10. It is concluded that the International Bureau of Weights and Measures, BIPM, in cooperation with the International Association for the Properties of Water and Steam, IAPWS, along with other international organizations and institutions, can make significant contributions by developing and recommending state-of-the-art solutions for these long standing metrological problems in climatology.

  10. Spiraling pathways of global deep waters to the surface of the Southern Ocean

    OpenAIRE

    Tamsitt, Veronica; Drake, Henri F.; Morrison, Adele K.; Talley, Lynne D.; Dufour, Carolina O.; Gray, Alison R.; Griffies, Stephen M.; Mazloff, Matthew R.; Sarmiento, Jorge L.; Wang, Jinbo; Weijer, Wilbert

    2017-01-01

    Upwelling of global deep waters to the sea surface in the Southern Ocean closes the global overturning circulation and is fundamentally important for oceanic uptake of carbon and heat, nutrient resupply for sustaining oceanic biological production, and the melt rate of ice shelves. However, the exact pathways and role of topography in Southern Ocean upwelling remain largely unknown. Here we show detailed upwelling pathways in three dimensions, using hydrographic observations and particle trac...

  11. Tests of Parameterized Langmuir Circulation Mixing in the Oceans Surface Mixed Layer II

    Science.gov (United States)

    2017-08-11

    inertial oscillations in the ocean are governed by three-dimensional processes that are not accounted for in a one-dimensional simulation , and it was...Unlimited 52 Paul Martin (228) 688-5447 Recent large-eddy simulations (LES) of Langmuir circulation (LC) within the surface mixed layer (SML) of...used in the Navy Coastal Ocean Model (NCOM) and tested for (a) a simple wind-mixing case, (b) simulations of the upper ocean thermal structure at Ocean

  12. Adsorption of cadmium by activated carbon cloth: influence of surface oxidation and solution pH.

    Science.gov (United States)

    Rangel-Mendez, J R; Streat, M

    2002-03-01

    The surface of activated carbon cloth (ACC), based on polyacrylonitrile fibre as a precursor, was oxidised using nitric acid, ozone and electrochemical oxidation to enhance cadmium ion exchange capacity. Modified adsorbents were physically and chemically characterised by pH titration, direct titration, X-ray photoelectron spectroscopy, elemental analysis, surface area and porosimetry, and scanning electron microscopy. BET surface area decreased after oxidation, however, the total ion exchange capacity increased by a factor of approximately 3.5 compared to the commercial as-received ACC. A very significant increase in cadmium uptake, by a factor of 13, was observed for the electrochemically oxidised ACC. Equilibrium sorption isotherms were determined at pH 4, 5 and 6 and these showed that cadmium uptake increased with increasing pH. There was clear evidence of physical damage to ozone-oxidised fibre, however, acid and electrochemically oxidised samples were completely stable.

  13. Unraveling the Reaction Chemistry of Icy Ocean World Surfaces

    Science.gov (United States)

    Hudson, R.; Loeffler, M. J.; Gerakines, P.

    2017-12-01

    The diverse endogenic chemistry of ocean worlds can be divided among interior, surface, and above-surface process, with contributions from exogenic agents such as solar, cosmic, and magnetospheric radiation. Bombardment from micrometeorites to comets also can influence chemistry by both delivering new materials and altering pre-existing ones, and providing energy to drive reactions. Geological processes further complicate the chemistry by transporting materials from one environment to another. In this presentation the focus will be on some of the thermally driven and radiation-induced changes expected from icy materials, primarily covalent and ionic compounds. Low-temperature conversions of a few relatively simple molecules into ions possessing distinct infrared (IR) features will be covered, with an emphasis on such features as might be identified through either orbiting spacecraft or landers. The low-temperature degradation of a few bioorganic molecules, such as DNA nucleobases and some common amino acids, will be used as examples of the more complex, and potentially misleading, chemistry expected for icy moons of the outer solar system. This work was supported by NASA's Emerging Worlds and Outer Planets Research programs, as well as the NASA Astrobiology Institute's Goddard Center for Astrobiology.

  14. Dissolved inorganic carbon, total alkalinity, pH, and other variables collected from surface discrete observations using spectrophotometer and other instruments from NOAA Ship Henry B. Bigelow off the Northeastern coast of the United States from 2014-09-10 to 2014-11-05 (NCEI Accession 0138983)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains surface measurements of dissolved inorganic, total alkalinity, pH measurements off the Northeastern coast of the United States....

  15. Dissolved inorganic carbon, total alkalinity, pH, nutrients, and other variables collected from surface discrete observations using Niskin bottle and other instruments from R/V F. G. Walton Smith in the west coast of Florida within Gulf of Mexico from 2015-09-23 to 2015-09-24 (NCEI Accession 0157025)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains the surface discrete measurements of dissolved inorganic carbon, total alkalinity, pH and nutrients in the west coast of Florida near...

  16. Dissolved inorganic carbon, total alkalinity, pH, and other variables collected from surface and discrete observations using Niskin bottle, flow-through pump and other instruments from F.G. Walton Smith in the Gulf of Mexico (east coast of Florida near the Keys) from 2014-12-03 to 2014-12-04 (NCEI Accession 0154383)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains surface discrete measurement of dissolved inorganic carbon, total alkalinity, pH, dissolved oxygen and nutrients from a transect off...

  17. Dissolved inorganic carbon, total alkalinity, pH, nutrients, and other variables collected from surface discrete observations using flow-through pump and other instruments from NOAA Ship Henry B. Bigelow on the Northeast U.S. Shelf (Gulf of Maine and Mid-Atlantic Bight) from 2013-03-17 to 2013-05-09 (NCEI Accession 0154386)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains surface discrete measurements of dissolved inorganic carbon, total alkalinity, pH and nutrients in the Mid-Atlantic Bight and Gulf of...

  18. The Ocean Surface Topography Sentinel-6/Jason-CS Mission

    Science.gov (United States)

    Giulicchi, L.; Cullen, R.; Donlon, C.; Vuilleumier@esa int, P.

    2016-12-01

    The Sentinel-6/Jason-CS mission consists of two identical satellites flying in sequence and designed to provide operational measurements of sea surface height significant wave high and wind speed to support operational oceanography and climate monitoring. The mission will be the latest in a series of ocean surface topography missions that will span nearly three decades. They follow the altimeters on- board TOPEX/Poseidon through to Jason-3 (launched in January 2016). Jason-CS will continue to fulfil objectives of the reference series whilst introducing a major enhancement in capability providing the operational and science oceanographic community with the state of the art in terms of spacecraft, measurement instrumentation design thus securing optimal operational and science data return. As a secondary objective the mission will also include Radio Occultation user services. Each satellite will be launched sequentially into the Jason orbit (up to 66 latitude) respectively in 2020 and 2025. The principle payload instrument is a high precision Ku/C band radar altimeter with retrieval of geophysical parameters (surface elevation, wind speed and SWH) from the altimeter data require supporting measurements: a DORIS receiver for Precise Orbit Determination; The Climate Quality Advanced Microwave Radiometer (AMR-C) for high stability path delay correction. Orbit tracking data are also provided by GPS & LRA. An additional GPS receiver will be dedicated to radio-occultation measurements. The programme is a part of the European Community Copernicus initiative, whose objective is to support Europe's goals regarding sustainable development and global governance of the environment by providing timely and quality data, information, services and knowledge. The Sentinel-6/Jason-CS in particular is a cooperative mission with contributions from NASA, NOAA, EUMETSAT, ESA, CNES and the European Union.

  19. Ocean current surface measurement using dynamic elevations obtained by the GEOS-3 radar altimeter

    Science.gov (United States)

    Leitao, C. D.; Huang, N. E.; Parra, C. G.

    1977-01-01

    Remote Sensing of the ocean surface from the GEOS-3 satellite using radar altimeter data has confirmed that the altimeter can detect the dynamic ocean topographic elevations relative to an equipotential surface, thus resulting in a reliable direct measurement of the ocean surface. Maps of the ocean dynamic topography calculated over a one month period and with 20 cm contour interval are prepared for the last half of 1975. The Gulf Stream is observed by the rapid slope change shown by the crowding of contours. Cold eddies associated with the current are seen as roughly circular depressions.

  20. Organelle-targeting surface-enhanced Raman scattering (SERS) nanosensors for subcellular pH sensing.

    Science.gov (United States)

    Shen, Yanting; Liang, Lijia; Zhang, Shuqin; Huang, Dianshuai; Zhang, Jing; Xu, Shuping; Liang, Chongyang; Xu, Weiqing

    2018-01-25

    The pH value of subcellular organelles in living cells is a significant parameter in the physiological activities of cells. Its abnormal fluctuations are commonly believed to be associated with cancers and other diseases. Herein, a series of surface-enhanced Raman scattering (SERS) nanosensors with high sensitivity and targeting function was prepared for the quantification and monitoring of pH values in mitochondria, nucleus, and lysosome. The nanosensors were composed of gold nanorods (AuNRs) functionalized with a pH-responsive molecule (4-mercaptopyridine, MPy) and peptides that could specifically deliver the AuNRs to the targeting subcellular organelles. The localization of our prepared nanoprobes in specific organelles was confirmed by super-high resolution fluorescence imaging and bio-transmission electron microscopy (TEM) methods. By the targeting ability, the pH values of the specific organelles can be determined by monitoring the vibrational spectral changes of MPy with different pH values. Compared to the cases of reported lysosome and cytoplasm SERS pH sensors, more accurate pH values of mitochondria and nucleus, which could be two additional intracellular tracers for subcellular microenvironments, were disclosed by this SERS approach, further improving the accuracy of discrimination of related diseases. Our sensitive SERS strategy can also be employed to explore crucial physiological and biological processes that are related to subcellular pH fluctuations.

  1. Surface currents in the equatorial Indian Ocean during spring and fall - An altimetry based analysis

    Digital Repository Service at National Institute of Oceanography (India)

    Antony, M.K.; Somayajulu, Y.K.

    This communication presents the results of a study aimed at investigating the nature and variability of surface currents in the equatorial Indian Ocean between 5 degrees N and 5 degrees S during spring and fall seasons. Geostrophic surface currents...

  2. Formation and maintenance of high-nitrate, low pH layers in the eastern Indian Ocean and the role of nitrogen fixation

    Directory of Open Access Journals (Sweden)

    A. M. Waite

    2013-08-01

    Full Text Available We investigated the biogeochemistry of low dissolved oxygen high-nitrate (LDOHN layers forming against the backdrop of several interleaving regional water masses in the eastern Indian Ocean, off northwest Australia adjacent to Ningaloo Reef. These water masses, including the forming Leeuwin Current, have been shown directly to impact the ecological function of Ningaloo Reef and other iconic coastal habitats downstream. Our results indicate that LDOHN layers are formed from multiple subduction events of the Eastern Gyral Current beneath the Leeuwin Current (LC; the LC originates from both the Indonesian Throughflow and tropical Indian Ocean. Density differences of up to 0.025 kg m−3 between the Eastern Gyral Current and the Leeuwin Current produce sharp gradients that can trap high concentrations of particles (measured as low transmission along the density interfaces. The oxidation of the trapped particulate matter results in local depletion of dissolved oxygen and regeneration of dissolved nitrate (nitrification. We document an associated increase in total dissolved carbon dioxide, which lowers the seawater pH by 0.04 units. Based on isotopic measurements (δ15N and δ18O of dissolved nitrate, we determine that ~ 40–100% of the nitrate found in LDOHN layers is likely to originate from nitrogen fixation, and that, regionally, the importance of N-fixation in contributing to LDOHN layers is likely to be highest at the surface and offshore.

  3. An update to the Surface Ocean CO2 Atlas (SOCAT version 2)

    NARCIS (Netherlands)

    Bakker, D.C.E.; Pfeil, B.; Smith, K.; Hankin, S.; Olsen, A.; Alin, S. R.; Cosca, C.; Harasawa, S.; Kozyr, A.; Nojiri, Y.; O'Brien, K. M.; Schuster, U.; Telszewski, M.; Tilbrook, B.; Wada, C.; Akl, J.; Barbero, L.; Bates, N. R.; Boutin, J.; Bozec, Y.; Cai, W. -J.; Castle, R. D.; Chavez, F. P.; Chen, L.; Chierici, M.; Currie, K.; de Baar, H. J. W.; Evans, W.; Feely, R. A.; Fransson, A.; Gao, Z.; Hales, B.; Hardman-Mountford, N. J.; Hoppema, M.; Huang, W. -J.; Hunt, C. W.; Huss, B.; Ichikawa, T.; Johannessen, T.; Jones, E. M.; Jones, S. D.; Jutterstrom, S.; Kitidis, V.; Koertzinger, A.; Landschuetzer, P.; Lauvset, S. K.; Lefevre, N.; Manke, A. B.; Mathis, J. T.; Merlivat, L.; Metzl, N.; Murata, A.; Newberger, T.; Omar, A. M.; Ono, T.; Park, G. -H.; Paterson, K.; Pierrot, D.; Rios, A. F.; Sabine, C. L.; Saito, S.; Salisbury, J.; Sarma, V. V. S. S.; Schlitzer, R.; Sieger, R.; Skjelvan, I.; Steinhoff, T.; Sullivan, K. F.; Sun, H.; Sutton, A. J.; Suzuki, T.; Sweeney, C.; Takahashi, T.; Tjiputra, J.; Tsurushima, N.; van Heuven, S. M. A. C.; Vandemark, D.; Vlahos, P.; Wallace, D. W. R.; Wanninkhof, R.; Watson, A.J.

    2014-01-01

    The Surface Ocean CO2 Atlas (SOCAT), an activity of the international marine carbon research community, provides access to synthesis and gridded fCO(2) (fugacity of carbon dioxide) products for the surface oceans. Version 2 of SOCAT is an update of the previous release (version 1) with more data

  4. Surface Ocean CO2 Atlas (SOCAT) gridded data products

    Digital Repository Service at National Institute of Oceanography (India)

    Sabine, C.L.; Hankin, S.; Koyuk, H.; Bakker, D.C.E.; Pfeil, B.; Olsen, A; Metzl, N.; Kozyr, A; Fassbender, A; Manke, A; Malczyk, J.; Akl, J.; Alin, S.R.; Bellerby, R.G.J.; Borges, A; Boutin, J.; Brown, P.J.; Cai, W.-J.; Chavez, F.P.; Chen, A.; Cosca, C.; Feely, R.A.; Gonzalez-Davila, M.; Goyet, C.; Hardman-Mountford, N.; Heinze, C.; Hoppema, M.; Hunt, C.W.; Hydes, D.; Ishii, M.; Johannessen, T.; Key, R.M.; Kortzinger, A.; Landschutzer, P.; Lauvset, S.K.; Lefevre, N.; Lenton, A.; Lourantou, A.; Merlivat, L.; Midorikawa, T.; Mintrop, L.; Miyazaki, C.; Murata, A.; Nakadate, A.; Nakano, Y.; Nakaoka, S.; Nojiri, Y.; Omar, A.M.; Padin, X.A.; Park, G.-H.; Paterson, K.; Perez, F.F.; Pierrot, D.; Poisson, A.; Rios, A.F.; Salisbury, J.; Santana-Casiano, J.M.; Sarma, V.V.S.S.; et al.

    As a response to public demand for a well-documented, quality controlled, publically available, global surface ocean carbon dioxide (CO2) data set, the international marine carbon science community developed the Surface Ocean CO2...

  5. From Urey To The Ocean's Glacial Ph: News From The Boron-11 Paleo-acidimetry.

    Science.gov (United States)

    Zeebe, R. E.; Wolf-Gladrow, D. A.; Bijma, J.

    Boron paleo-acidimetry is based on the stable boron isotope composition of foraminiferal shells which has been shown to be a function of seawater pH. It is cur- rently one of the most promising paleo-carbonate chemistry proxies. One important parameter of the proxy is the equilibrium fractionation between the dissolved boron species B(OH)3 and B(OH)- which was calculated to be 19 per mil at 25C by Kak- 4 ihana and Kotaka (1977), based on Urey's theory. The calculated equilibrium frac- tionation, however, depends on the vibrational frequencies of the molecules for which different values have been reported in the literature. We have recalculated the equilib- rium fractionation and find that it may be distinctly different from 19 per mil (this is the bad news). The good news is that - theoretically - the use of 11B as a paleo-pH indicator is not compromised through vital effects in planktonic foraminifera. We de- rive this conclusion by the use of a diffusion-reaction model that calculates pH profiles and 11B values in the vicinity of a foraminifer.

  6. Scaling and diffusion of oil spills in the Ocean Surface

    Science.gov (United States)

    Tarquis, A. M.; Platonov, A.; Grau, J.; Sekula, E.

    2010-05-01

    The region of the Gulf of Lions at the northwestern Mediterranean Sea has been studied within a ten-year period from December 1996 until November 2006. More than 1000 synthetic aperture radar (SAR) images, which have been acquired by the Second European Remote Sensing Satellite (ERS 1/2) as well as from ENVISAT. We present statistical results of the structure of several features revealed by SAR such as oil spills and tensioactive slicks dynamic. We compare oil splils obtained from the projects Clean Seas,ENVA4/CT/0334, RC2003/005700, ESP2005/07551 and ESA/AO/IP2240. Since natural (caused by plankton, fish, etc.) slicks as well as man-made oil slicks dampen the small-scale surface waves, which are responsible for the radar backscattering from the ocean surface, both types of effects may be confused and give look/alike false oil spill detections. The early SAR images were processed at a resolution of 1 pixel=200m and were provided by the RApid Information Dissemination System (RAIDS) SAR processing facility in West Freugh, UK. Recent ENVISAT images directly from ESA allow a higher resolution of 1 pixel = 26 m, improving the detected turbulent scaling range. The occurrence of marine oil pollution as well as several dynamic features near Barcelona (frames 8-10, 19, 20; 200 SAR images)is itself a random multi-scale process. The use of different multifractal techniques, both using limits to the smallest and largest available scales, show that the scaling laws are very complex and depend strongly on intermittency of the assumed turbulent cascade, the shapes of the multifractal spectra functions are seen to deviate from an homogeneous multifractal and depend both on the initial conditions of the spill or slick, and on the transit time that the spill has been subjected to the local turbulence.

  7. The Surface Radiation Budget over Oceans and Continents.

    Science.gov (United States)

    Garratt, J. R.; Prata, A. J.; Rotstayn, L. D.; McAvaney, B. J.; Cusack, S.

    1998-08-01

    An updated evaluation of the surface radiation budget in climate models (1994-96 versions; seven datasets available, with and without aerosols) and in two new satellite-based global datasets (with aerosols) is presented. All nine datasets capture the broad mean monthly zonal variations in the flux components and in the net radiation, with maximum differences of some 100 W m2 occurring in the downwelling fluxes at specific latitudes. Using long-term surface observations, both from land stations and the Pacific warm pool (with typical uncertainties in the annual values varying between ±5 and 20 W m2), excess net radiation (RN) and downwelling shortwave flux density (So) are found in all datasets, consistent with results from earlier studies [for global land, excesses of 15%-20% (12 W m2) in RN and about 12% (20 W m2) in So]. For the nine datasets combined, the spread in annual fluxes is significant: for RN, it is 15 (50) W m2 over global land (Pacific warm pool) in an observed annual mean of 65 (135) W m2; for So, it is 25 (60) W m2 over land (warm pool) in an annual mean of 176 (197) W m2.The effects of aerosols are included in three of the authors' datasets, based on simple aerosol climatologies and assumptions regarding aerosol optical properties. They offer guidance on the broad impact of aerosols on climate, suggesting that the inclusion of aerosols in models would reduce the annual So by 15-20 W m2 over land and 5-10 W m2 over the oceans. Model differences in cloud cover contribute to differences in So between datasets; for global land, this is most clearly demonstrated through the effects of cloud cover on the surface shortwave cloud forcing. The tendency for most datasets to underestimate cloudiness, particularly over global land, and possibly to underestimate atmospheric water vapor absorption, probably contributes to the excess downwelling shortwave flux at the surface.

  8. A cell-surface-anchored ratiometric i-motif sensor for extracellular pH detection.

    Science.gov (United States)

    Ying, Le; Xie, Nuli; Yang, Yanjing; Yang, Xiaohai; Zhou, Qifeng; Yin, Bincheng; Huang, Jin; Wang, Kemin

    2016-06-14

    A FRET-based sensor is anchored on the cell surface through streptavidin-biotin interactions. Due to the excellent properties of the pH-sensitive i-motif structure, the sensor can detect extracellular pH with high sensitivity and excellent reversibility.

  9. Improving NOAA's NWLON Through Enhanced Data Inputs from NASA's Ocean Surface Topography

    Science.gov (United States)

    Guest, DeNeice C.

    2010-01-01

    This report assesses the benefit of incorporating NASA's OSTM (Ocean Surface Topography Mission) altimeter data (C- and Ku-band) into NOAA's (National Oceanic and Atmospheric Administration) NWLON (National Water Level Observation Network) DSS (Decision Support System). This data will enhance the NWLON DSS by providing additional inforrnation because not all stations collect all meteorological parameters (sea-surface height, ocean tides, wave height, and wind speed over waves). OSTM will also provide data where NWLON stations are not present. OSTM will provide data on seasurface heights for determining sea-level rise and ocean circulation. Researchers and operational users currently use satellite altimeter data products with the GSFCOO NASA data model to obtain sea-surface height and ocean circulation inforrnation. Accurate and tirnely inforrnation concerning sea-level height, tide, and ocean currents is needed to irnprove coastal tidal predictions, tsunarni and storm surge warnings, and wetland restoration.

  10. Surface wave effect on the upper ocean in marine forecast

    Science.gov (United States)

    Wang, Guansuo; Qiao, Fangli; Xia, Changshui; Zhao, Chang

    2015-04-01

    An Operational Coupled Forecast System for the seas off China and adjacent (OCFS-C) is constructed based on the paralleled wave-circulation coupled model, which is tested with comprehensive experiments and operational since November 1st, 2007. The main feature of the system is that the wave-induced mixing is considered in circulation model. Daily analyses and three day forecasts of three-dimensional temperature, salinity, currents and wave height are produced. Coverage is global at 1/2 degreed resolution with nested models up to 1/24 degree resolution in China Sea. Daily remote sensing sea surface temperatures (SST) are taken to relax to an analytical product as hot restarting fields for OCFS-C by the Nudging techniques. Forecasting-data inter-comparisons are performed to measure the effectiveness of OCFS-C in predicting upper-ocean quantities including SST, mixed layer depth (MLD) and subsurface temperature. The variety of performance with lead time and real-time is discussed as well using the daily statistic results for SST between forecast and satellite data. Several buoy observations and many Argo profiles are used for this validation. Except the conventional statistical metrics, non-dimension skill scores (SS) is taken to estimate forecast skill. Model SST comparisons with more one year-long SST time series from 2 buoys given a large SS value (more than 0.90). And skill in predicting the seasonal variability of SST is confirmed. Model subsurface temperature comparisons with that from a lot of Argo profiles indicated that OCFS-C has low skill in predicting subsurface temperatures between 80m and 120m. Inter-comparisons of MLD reveal that MLD from model is shallower than that from Argo profiles by about 12m. QCFS-C is successful and steady in predicting MLD. The daily statistic results for SST between 1-d, 2-d and 3-d forecast and data is adopted to describe variability of Skill in predicting SST with lead time or real time. In a word QCFS-C shows reasonable

  11. Investigating the Potential Impact of the Surface Water and Ocean Topography (SWOT) Altimeter on Ocean Mesoscale Prediction

    Science.gov (United States)

    Carrier, M.; Ngodock, H.; Smith, S. R.; Souopgui, I.

    2016-02-01

    NASA's Surface Water and Ocean Topography (SWOT) satellite, scheduled for launch in 2020, will provide sea surface height anomaly (SSHA) observations with a wider swath width and higher spatial resolution than current satellite altimeters. It is expected that this will help to further constrain ocean models in terms of the mesoscale circulation. In this work, this expectation is investigated by way of twin data assimilation experiments using the Navy Coastal Ocean Model Four Dimensional Variational (NCOM-4DVAR) data assimilation system using a weak constraint formulation. Here, a nature run is created from which SWOT observations are sampled, as well as along-track SSHA observations from simulated Jason-2 tracks. The simulated SWOT data has appropriate spatial coverage, resolution, and noise characteristics based on an observation-simulator program provided by the SWOT science team. The experiment is run for a three-month period during which the analysis is updated every 24 hours and each analysis is used to initialize a 96 hour forecast. The forecasts in each experiment are compared to the available nature run to determine the impact of the assimilated data. It is demonstrated here that the SWOT observations help to constrain the model mesoscale in a more consistent manner than traditional altimeter observations. The findings of this study suggest that data from SWOT may have a substantial impact on improving the ocean model analysis and forecast of mesoscale features and surface ocean transport.

  12. 3-D Surface Visualization of pH Titration "Topos": Equivalence Point Cliffs, Dilution Ramps, and Buffer Plateaus

    Science.gov (United States)

    Smith, Garon C.; Hossain, Md Mainul; MacCarthy, Patrick

    2014-01-01

    3-D topographic surfaces ("topos") can be generated to visualize how pH behaves during titration and dilution procedures. The surfaces are constructed by plotting computed pH values above a composition grid with volume of base added in one direction and overall system dilution on the other. What emerge are surface features that…

  13. Metal release from contaminated coastal sediments under changing pH conditions: Implications for metal mobilization in acidified oceans.

    Science.gov (United States)

    Wang, Zaosheng; Wang, Yushao; Zhao, Peihong; Chen, Liuqin; Yan, Changzhou; Yan, Yijun; Chi, Qiaoqiao

    2015-12-30

    To investigate the impacts and processes of CO2-induced acidification on metal mobilization, laboratory-scale experiments were performed, simulating the scenarios where carbon dioxide was injected into sediment-seawater layers inside non-pressurized chambers. Coastal sediments were sampled from two sites with different contamination levels and subjected to pre-determined pH conditions. Sediment samples and overlying water were collected for metal analysis after 10-days. The results indicated that CO2-induced ocean acidification would provoke increased metal mobilization causing adverse side-effects on water quality. The mobility of metals from sediment to the overlying seawater was correlated with the reduction in pH. Results of sequential extractions of sediments illustrated that exchangeable metal forms were the dominant source of mobile metals. Collectively, our data revealed that high metal concentrations in overlying seawater released from contaminated sediments under acidic conditions may strengthen the existing contamination gradients in Maluan Bay and represent a potential risk to ecosystem health in coastal environments. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. pH Mapping on Tooth Surfaces for Quantitative Caries Diagnosis Using Micro Ir/IrOx pH Sensor.

    Science.gov (United States)

    Ratanaporncharoen, Chindanai; Tabata, Miyuki; Kitasako, Yuichi; Ikeda, Masaomi; Goda, Tatsuro; Matsumoto, Akira; Tagami, Junji; Miyahara, Yuji

    2018-04-03

    A quantitative diagnostic method for dental caries would improve oral health, which directly affects the quality of life. Here we describe the preparation and application of Ir/IrOx pH sensors, which are used to measure the surface pH of dental caries. The pH level is used as an indicator to distinguish between active and arrested caries. After a dentist visually inspected and defined 18 extracted dentinal caries at various positions as active or arrested caries, the surface pH values of sound and caries areas were directly measured with an Ir/IrOx pH sensor with a diameter of 300 μm as a dental explorer. The average pH values of the sound root, the arrested caries, and active caries were 6.85, 6.07, and 5.30, respectively. The pH obtained with an Ir/IrOx sensor was highly correlated with the inspection results by the dentist, indicating that the types of caries were successfully categorized. This caries testing technique using a micro Ir/IrOx pH sensor provides an accurate quantitative caries evaluation and has potential in clinical diagnosis.

  15. Evaluation of Oceanic Surface Observation for Reproducing the Upper Ocean Structure in ECHAM5/MPI-OM

    Science.gov (United States)

    Luo, Hao; Zheng, Fei; Zhu, Jiang

    2017-12-01

    Better constraints of initial conditions from data assimilation are necessary for climate simulations and predictions, and they are particularly important for the ocean due to its long climate memory; as such, ocean data assimilation (ODA) is regarded as an effective tool for seasonal to decadal predictions. In this work, an ODA system is established for a coupled climate model (ECHAM5/MPI-OM), which can assimilate all available oceanic observations using an ensemble optimal interpolation approach. To validate and isolate the performance of different surface observations in reproducing air-sea climate variations in the model, a set of observing system simulation experiments (OSSEs) was performed over 150 model years. Generally, assimilating sea surface temperature, sea surface salinity, and sea surface height (SSH) can reasonably reproduce the climate variability and vertical structure of the upper ocean, and assimilating SSH achieves the best results compared to the true states. For the El Niño-Southern Oscillation (ENSO), assimilating different surface observations captures true aspects of ENSO well, but assimilating SSH can further enhance the accuracy of ENSO-related feedback processes in the coupled model, leading to a more reasonable ENSO evolution and air-sea interaction over the tropical Pacific. For ocean heat content, there are still limitations in reproducing the long time-scale variability in the North Atlantic, even if SSH has been taken into consideration. These results demonstrate the effectiveness of assimilating surface observations in capturing the interannual signal and, to some extent, the decadal signal but still highlight the necessity of assimilating profile data to reproduce specific decadal variability.

  16. The impact of changing surface ocean conditions on the dissolution of aerosol iron

    Science.gov (United States)

    Fishwick, Matthew P.; Sedwick, Peter N.; Lohan, Maeve C.; Worsfold, Paul J.; Buck, Kristen N.; Church, Thomas M.; Ussher, Simon J.

    2014-11-01

    The proportion of aerosol iron (Fe) that dissolves in seawater varies greatly and is dependent on aerosol composition and the physicochemical conditions of seawater, which may change depending on location or be altered by global environmental change. Aerosol and surface seawater samples were collected in the Sargasso Sea and used to investigate the impact of these changing conditions on aerosol Fe dissolution in seawater. Our data show that seawater temperature, pH, and oxygen concentration, within the range of current and projected future values, had no significant effect on the dissolution of aerosol Fe. However, the source and composition of aerosols had the most significant effect on the aerosol Fe solubility, with the most anthropogenically influenced samples having the highest fractional solubility (up to 3.2%). The impact of ocean warming and acidification on aerosol Fe dissolution is therefore unlikely to be as important as changes in land usage and fossil fuel combustion. Our experimental results also reveal important changes in the size distribution of soluble aerosol Fe in solution, depending on the chemical conditions of seawater. Under typical conditions, the majority (77-100%) of Fe released from aerosols into ambient seawater existed in the colloidal (0.02-0.4 µm) size fraction. However, in the presence of a sufficient concentration of strong Fe-binding organic ligands (10 nM) most of the aerosol-derived colloidal Fe was converted to soluble Fe (<0.02 µm). This finding highlights the potential importance of organic ligands in retaining aerosol Fe in a biologically available form in the surface ocean.

  17. Comparison of the ocean surface vector winds over the Nordic Seas and their application for ocean modeling

    Science.gov (United States)

    Dukhovskoy, Dmitry; Bourassa, Mark

    2017-04-01

    Ocean processes in the Nordic Seas and northern North Atlantic are strongly controlled by air-sea heat and momentum fluxes. The predominantly cyclonic, large-scale atmospheric circulation brings the deep ocean layer up to the surface preconditioning the convective sites in the Nordic Seas for deep convection. In winter, intensive cooling and possibly salt flux from newly formed sea ice erodes the near-surface stratification and the mixed layer merges with the deeper domed layer, exposing the very weakly stratified deep water mass to direct interaction with the atmosphere. Surface wind is one of the atmospheric parameters required for estimating momentum and turbulent heat fluxes to the sea ice and ocean surface. In the ocean models forced by atmospheric analysis, errors in surface wind fields result in errors in air-sea heat and momentum fluxes, water mass formation, ocean circulation, as well as volume and heat transport in the straits. The goal of the study is to assess discrepancies across the wind vector fields from reanalysis data sets and scatterometer-derived gridded products over the Nordic Seas and northern North Atlantic and to demonstrate possible implications of these differences for ocean modeling. The analyzed data sets include the reanalysis data from the National Center for Environmental Prediction Reanalysis 2 (NCEPR2), Climate Forecast System Reanalysis (CFSR), Arctic System Reanalysis (ASR) and satellite wind products Cross-Calibrated Multi-Platform (CCMP) wind product version 1.1 and recently released version 2.0, and Remote Sensing Systems QuikSCAT data. Large-scale and mesoscale characteristics of winds are compared at interannual, seasonal, and synoptic timescales. Numerical sensitivity experiments are conducted with a coupled ice-ocean model forced by different wind fields. The sensitivity experiments demonstrate differences in the net surface heat fluxes during storm events. Next, it is hypothesized that discrepancies in the wind vorticity

  18. Marine isoprene production and consumption in the mixed layer of the surface ocean - a field study over two oceanic regions

    Science.gov (United States)

    Booge, Dennis; Schlundt, Cathleen; Bracher, Astrid; Endres, Sonja; Zäncker, Birthe; Marandino, Christa A.

    2018-02-01

    Parameterizations of surface ocean isoprene concentrations are numerous, despite the lack of source/sink process understanding. Here we present isoprene and related field measurements in the mixed layer from the Indian Ocean and the eastern Pacific Ocean to investigate the production and consumption rates in two contrasting regions, namely oligotrophic open ocean and the coastal upwelling region. Our data show that the ability of different phytoplankton functional types (PFTs) to produce isoprene seems to be mainly influenced by light, ocean temperature, and salinity. Our field measurements also demonstrate that nutrient availability seems to have a direct influence on the isoprene production. With the help of pigment data, we calculate in-field isoprene production rates for different PFTs under varying biogeochemical and physical conditions. Using these new calculated production rates, we demonstrate that an additional significant and variable loss, besides a known chemical loss and a loss due to air-sea gas exchange, is needed to explain the measured isoprene concentration. We hypothesize that this loss, with a lifetime for isoprene between 10 and 100 days depending on the ocean region, is potentially due to degradation or consumption by bacteria.

  19. Transgenerational exposure of North Atlantic bivalves to ocean acidification renders offspring more vulnerable to low pH and additional stressors.

    Science.gov (United States)

    Griffith, Andrew W; Gobler, Christopher J

    2017-09-12

    While early life-stage marine bivalves are vulnerable to ocean acidification, effects over successive generations are poorly characterized. The objective of this work was to assess the transgenerational effects of ocean acidification on two species of North Atlantic bivalve shellfish, Mercenaria mercenaria and Argopecten irradians. Adults of both species were subjected to high and low pCO 2 conditions during gametogenesis. Resultant larvae were exposed to low and ambient pH conditions in addition to multiple, additional stressors including thermal stress, food-limitation, and exposure to a harmful alga. There were no indications of transgenerational acclimation to ocean acidification during experiments. Offspring of elevated pCO 2 -treatment adults were significantly more vulnerable to acidification as well as the additional stressors. Our results suggest that clams and scallops are unlikely to acclimate to ocean acidification over short time scales and that as coastal oceans continue to acidify, negative effects on these populations may become compounded and more severe.

  20. The Ocean Surface Topography SENTINEL-6/JASON-CS Mission

    Science.gov (United States)

    Cullen, R.

    2015-12-01

    The Sentinel-6/Jason-CS mission will consist of 2 spacecraft and will be the latest in a series of ocean surface topography missions that will span nearly three decades. They follow the altimeters on- board TOPEX/Poseidon through to Jason-3 (expected March 2015). Jason-CS will continue to fulfil objectives of the reference series whilst introducing a major enhancement in capability providing the operational and science oceanographic community with the state of the art in terms of platform, measurement instrumentation design thus securing optimal operational and science data return. The programme is a part of the EC Copernicus initiative, whose objective is to support Europe's goals regarding sustainable development and global governance of the environment by providing timely and quality data, information, services and knowledge. The programme brings together: ESA for development, procurement & early orbit activities; EUMETSAT for mission management, ground segment, flight ops, contributing funding of the 1st satellite and participation in funding for the 2nd satellite; NASA for the US payload and launcher procurement in addition to funding US science opportunities; EC for funding the operations and participation in funding (with EUMETSAT) for the 2nd satellite; NOAA are expected to provide US ground stations & operations services; CNES for mission expertise and provision of the POD service. The consortium plan to procure 2 satellites with the 1st planned for launch readiness in the 1st half of 2020 with the 2nd satellite 5 years later. The first major commitment to funding was given by the ESA member states that approved the programme in June 2014 and in addition the European Commission funding is also fully secure. The design is based on a platform derived from CryoSat-2 adjusted to the specific requirements of the higher orbit. The principle payload instrument is a high precision Ku/C band radar altimeter with retrieval of geophysical parameters (surface

  1. The Ocean Surface Topography JASON-CS/SENTINEL-6 Mission

    Science.gov (United States)

    Cullen, R.; Francis, R.

    2014-12-01

    The Jason-CS/Sentinel-6 programme will consist of 2 spacecraft and will be the latest in a series of ocean surface topography missions that will span nearly three decades. They follow the altimeters on-board TOPEX/Poseidon through to Jason-3 (expected March 2015). Jason-CS will continue to fulfil objectives of the reference series whilst introducing a major enhancement in capability providing the operational and science oceanographic community with the state of the art in terms of platform, measurement instrumentation design thus securing optimal operational and science data return. The programme is a part of the EC Copernicus initiative, whose objective is to support Europe's goals regarding sustainable development and global governance of the environment by providing timely and quality data, information, services and knowledge. The programme brings together: ESA for development, procurement & early orbit activities; EUMETSAT for mission management, ground segment, flight ops, contributing funding of the 1st satellite and participation in funding for the 2nd satellite; NOAA for US payload instruments, launcher, ground stations & operations; NASA for developing the US payload, launcher procurement and funding US science; EU for funding the operations and participation in funding (with EUMETSAT) for the 2nd satellite; CNES for mission expertise and provision of POD. The consortium plan to procure 2 satellites with the 1st planned for launch readiness in the 1st half of 2020 with the 2nd satellite 5 years later. The first major commitment to funding was given by the ESA member states that approved the programme in June 2014 and in addition the European Union funding is also secure. The design will be based on a platform derived from CryoSat-2 but adjusted to the specific requirements of the higher orbit. The principle payload instrument is a high precision Ku/C band radar altimeter with retrieval of geophysical parameters (surface elevation, wind speed and SWH) from

  2. Transport and scavenging of Pu in surface waters of the Southern Hemisphere Oceans

    DEFF Research Database (Denmark)

    Gastaud, J.; Povinec, P.P.; Aoyama, M.

    2011-01-01

    The distribution of 239Pu in Atlantic and Indian Ocean waters about four decades after their main injection from atmospheric nuclear weapons tests is discussed. Recent data obtained in the framework of the SHOTS (Southern Hemisphere Ocean Tracer Studies) projects are evaluated and compared...... with previous investigations. Seawater samples were collected during the round the globe BEAGLE2003 (Blue Ocean Global Expedition) along the 30°S transect in the Atlantic and the 20°S transect in the Indian Ocean. The results indicate transport of surface waters labelled with 239Pu from the western North...... Pacific via the Indonesian Seas to the South Indian Ocean and then to the South Atlantic Ocean. Along the whole BEAGLE2003 sampling route, the Atlantic Ocean has the lowest 239Pu content due to its particle scavenging on the long way from the western North Pacific. On the other hand, concentrations...

  3. Iodine isotopes species fingerprinting environmental conditions in surface water along the northeastern Atlantic Ocean

    DEFF Research Database (Denmark)

    He, Peng; Hou, Xiaolin; Aldahan, Ala

    2013-01-01

    Concentrations and species of iodine isotopes (127I and 129I) provide vital information about iodine geochemistry, environmental conditions and water masses exchange in oceans. Despite extensive investigations of anthropogenic 129I in the Arctic Ocean and the Nordic Seas, concentrations of the is...... 129I in ocean environments and impact on climate at the ocean boundary layer.......Concentrations and species of iodine isotopes (127I and 129I) provide vital information about iodine geochemistry, environmental conditions and water masses exchange in oceans. Despite extensive investigations of anthropogenic 129I in the Arctic Ocean and the Nordic Seas, concentrations...... of the isotope in the Atlantic Ocean are, however, still unknown. We here present first data on 129I and 127I, and their species (iodide and iodate) in surface water transect along the northeastern Atlantic between 30° and 50°N. The results show iodate as the predominant species in the analyzed marine waters...

  4. Turbulence Scaling Comparisons in the Ocean Surface Boundary Layer

    Science.gov (United States)

    Esters, L.; Breivik, Ø.; Landwehr, S.; ten Doeschate, A.; Sutherland, G.; Christensen, K. H.; Bidlot, J.-R.; Ward, B.

    2018-03-01

    Direct observations of the dissipation rate of turbulent kinetic energy, ɛ, under open ocean conditions are limited. Consequently, our understanding of what chiefly controls dissipation in the open ocean, and its functional form with depth, is poorly constrained. In this study, we report direct open ocean measurements of ɛ from the Air-Sea Interaction Profiler (ASIP) collected during five different cruises in the Atlantic Ocean. We then combine these data with ocean-atmosphere flux measurements and wave information in order to evaluate existing turbulence scaling theories under a diverse set of open ocean conditions. Our results do not support the presence of a "breaking" or a "transition layer," which has been previously suggested. Instead, ɛ decays as |z|-1.29 over the depth interval, which was previously defined as "transition layer," and as |z|-1.15 over the mixing layer. This depth dependency does not significantly vary between nonbreaking or breaking wave conditions. A scaling relationship based on the friction velocity, the wave age, and the significant wave height describes the observations best for daytime conditions. For conditions during which convection is important, it is necessary to take buoyancy forcing into account.

  5. How well-connected is the surface of the global ocean?

    OpenAIRE

    Froyland, G; Stuart, RM; van Sebille, E

    2014-01-01

    The Ekman dynamics of the ocean surface circulation is known to contain attracting regions such as the great oceanic gyres and the associated garbage patches. Less well-known are the extents of the basins of attractions of these regions and how strongly attracting they are. Understanding the shape and extent of the basins of attraction sheds light on the question of the strength of connectivity of different regions of the ocean, which helps in understanding the flow of buoyant material like p...

  6. Respiration of new and old carbon in the surface ocean: Implications for estimates of global oceanic gross primary productivity

    Science.gov (United States)

    Carvalho, Matheus C.; Schulz, Kai G.; Eyre, Bradley D.

    2017-06-01

    New respiration (Rnew, of freshly fixated carbon) and old respiration (Rold, of storage carbon) were estimated for different regions of the global surface ocean using published data on simultaneous measurements of the following: (1) primary productivity using 14C (14PP); (2) gross primary productivity (GPP) based on 18O or O2; and (3) net community productivity (NCP) using O2. The ratio Rnew/GPP in 24 h incubations was typically between 0.1 and 0.3 regardless of depth and geographical area, demonstrating that values were almost constant regardless of large variations in temperature (0 to 27°C), irradiance (surface to 100 m deep), nutrients (nutrient-rich and nutrient-poor waters), and community composition (diatoms, flagellates, etc,). As such, between 10 and 30% of primary production in the surface ocean is respired in less than 24 h, and most respiration (between 55 and 75%) was of older carbon. Rnew was most likely associated with autotrophs, with minor contribution from heterotrophic bacteria. Patterns were less clear for Rold. Short 14C incubations are less affected by respiratory losses. Global oceanic GPP is estimated to be between 70 and 145 Gt C yr-1.Plain Language SummaryHere we present a comprehensive coverage of ocean new and old respiration. Our results show that nearly 20% of oceanic gross primary production is consumed in the first 24 h. However, most (about 60%) respiration is of older carbon fixed at least 24 h before its consumption. Rates of new respiration relative to gross primary production were remarkably constant for the entire ocean, which allowed a preliminary estimation of global primary productivity as between 70 and 145 gt C yr-1.

  7. Targeting diseased tissues by pHLIP insertion at low cell surface pH

    Directory of Open Access Journals (Sweden)

    Oleg A. Andreev

    2014-03-01

    Full Text Available The discovery of the pH Low Insertion Peptides (pHLIPs provides an opportunity to develop imaging and drug delivery agents targeting extracellular acidity. Extracellular acidity is associated with many pathological states, such as those in cancer, ischemic stroke, neurotrauma, infection, lacerations and others. The metabolism of cells in injured or diseased tissues often results in the acidification of the extracellular environment, so acidosis might be useful as a general marker for the imaging and treatment of diseased states if an effective targeting method can be developed. The molecular mechanism of a pHLIP peptide is based on pH-dependent membrane-associated folding. pHLIPs, being moderately hydrophobic peptides, have high affinities for cellular membranes at normal pH, but fold and insert across membranes at low pH, allowing them to sense pH at the surfaces of cells in diseased tissues, where it is the lowest. Here we discuss the main principles of pHLIP interactions with membrane lipid bilayers at neutral and low pHs, the possibility of tuning the folding and insertion pH by peptide sequence variation, and potential applications of pHLIPs for imaging, therapy and image-guided interventions.

  8. Targeting diseased tissues by pHLIP insertion at low cell surface pH.

    Science.gov (United States)

    Andreev, Oleg A; Engelman, Donald M; Reshetnyak, Yana K

    2014-01-01

    The discovery of the pH Low Insertion Peptides (pHLIPs®) provides an opportunity to develop imaging and drug delivery agents targeting extracellular acidity. Extracellular acidity is associated with many pathological states, such as those in cancer, ischemic stroke, neurotrauma, infection, lacerations, and others. The metabolism of cells in injured or diseased tissues often results in the acidification of the extracellular environment, so acidosis might be useful as a general marker for the imaging and treatment of diseased states if an effective targeting method can be developed. The molecular mechanism of a pHLIP peptide is based on pH-dependent membrane-associated folding. pHLIPs, being moderately hydrophobic peptides, have high affinities for cellular membranes at normal pH, but fold and insert across membranes at low pH, allowing them to sense pH at the surfaces of cells in diseased tissues, where it is the lowest. Here we discuss the main principles of pHLIP interactions with membrane lipid bilayers at neutral and low pHs, the possibility of tuning the folding and insertion pH by peptide sequence variation, and potential applications of pHLIPs for imaging, therapy and image-guided interventions.

  9. Variability of the reflectance coefficient of skylight from the ocean surface and its implications to ocean color.

    Science.gov (United States)

    Gilerson, Alexander; Carrizo, Carlos; Foster, Robert; Harmel, Tristan

    2018-04-16

    The value and spectral dependence of the reflectance coefficient (ρ) of skylight from wind-roughened ocean surfaces is critical for determining accurate water leaving radiance and remote sensing reflectances from shipborne, AERONET-Ocean Color and satellite observations. Using a vector radiative transfer code, spectra of the reflectance coefficient and corresponding radiances near the ocean surface and at the top of the atmosphere (TOA) are simulated for a broad range of parameters including flat and windy ocean surfaces with wind speeds up to 15 m/s, aerosol optical thicknesses of 0-1 at 440nm, wavelengths of 400-900 nm, and variable Sun and viewing zenith angles. Results revealed a profound impact of the aerosol load and type on the spectral values of ρ. Such impacts, not included yet in standard processing, may produce significant inaccuracies in the reflectance spectra retrieved from above-water radiometry and satellite observations. Implications for satellite cal/val activities as well as potential changes in measurement and data processing schemes are discussed.

  10. Stratum corneum hydration and skin surface pH in patients with atopic dermatitis.

    Science.gov (United States)

    Knor, Tanja; Meholjić-Fetahović, Ajša; Mehmedagić, Aida

    2011-01-01

    Atopic dermatitis (AD) is a chronically relapsing skin disease with genetic predisposition, which occurs most frequently in preschool children. It is considered that dryness and pruritus, which are always present in AD, are in correlation with degradation of the skin barrier function. Measurement of hydration and pH value of the stratum corneum is one of the noninvasive methods for evaluation of skin barrier function. The aim of the study was to assess skin barrier function by measuring stratum corneum hydration and skin surface pH of the skin with lesions, perilesional skin and uninvolved skin in AD patients, and skin in a healthy control group. Forty-two patients were included in the study: 21 young and adult AD patients and 21 age-matched healthy controls. Capacitance, which is correlated with hydration of stratum corneum and skin surface pH were measured on the forearm in the above areas by SM810/CM820/pH900 combined units (Courage AND Khazaka, Germany). The mean value of water capacitance measured in AD patients was 44.1 ± 11.6 AU (arbitrary units) on the lesions, 60.2 ± 12.4 AU on perilesional skin and 67.2 ± 8.8 AU on uninvolved skin. In healthy controls, the mean value was 74.1 ± 9.2 AU. The mean pH value measured in AD patients was 6.13 ± 0.52 on the lesions, 5.80 ± 0.41 on perilesional skin, and 5.54 ± 0.49 on uninvolved skin. In control group, the mean pH of the skin surface was 5.24 ± 0.40. The values of both parameters measured on lesional skin were significantly different (capacitance decreased and pH increased) from the values recorded on perilesional skin and uninvolved skin. The same held for the relation between perilesional and uninvolved skin. According to study results, the uninvolved skin of AD patients had significantly worse values of the measured parameters as compared with control group. The results of this study suggested the skin barrier function to be degraded in AD patients, which is specifically expressed in lesional skin.

  11. On-chip surface modified nanostructured ZnO as functional pH sensors

    International Nuclear Information System (INIS)

    Zhang, Qing; Liu, Wenpeng; Sun, Chongling; Zhang, Hao; Pang, Wei; Zhang, Daihua; Duan, Xuexin

    2015-01-01

    Zinc oxide (ZnO) nanostructures are promising candidates as electronic components for biological and chemical applications. In this study, ZnO ultra-fine nanowire (NW) and nanoflake (NF) hybrid structures have been prepared by Au-assisted chemical vapor deposition (CVD) under ambient pressure. Their surface morphology, lattice structures, and crystal orientation were investigated by scanning electron microscopy (SEM), x-ray diffraction (XRD), and transmission electron microscopy (TEM). Two types of ZnO nanostructures were successfully integrated as gate electrodes in extended-gate field-effect transistors (EGFETs). Due to the amphoteric properties of ZnO, such devices function as pH sensors. We found that the ultra-fine NWs, which were more than 50 μm in length and less than 100 nm in diameter, performed better in the pH sensing process than NW–NF hybrid structures because of their higher surface-to-volume ratio, considering the Nernst equation and the Gouy–Chapman–Stern model. Furthermore, the surface coating of (3-Aminopropyl)triethoxysilane (APTES) protects ZnO nanostructures in both acidic and alkaline environments, thus enhancing the device stability and extending its pH sensing dynamic range. (paper)

  12. Satellite-based Calibration of Heat Flux at the Ocean Surface

    Science.gov (United States)

    Barron, C. N.; Dastugue, J. M.; May, J. C.; Rowley, C. D.; Smith, S. R.; Spence, P. L.; Gremes-Cordero, S.

    2016-02-01

    Model forecasts of upper ocean heat content and variability on diurnal to daily scales are highly dependent on estimates of heat flux through the air-sea interface. Satellite remote sensing is applied to not only inform the initial ocean state but also to mitigate errors in surface heat flux and model representations affecting the distribution of heat in the upper ocean. Traditional assimilation of sea surface temperature (SST) observations re-centers ocean models at the start of each forecast cycle. Subsequent evolution depends on estimates of surface heat fluxes and upper-ocean processes over the forecast period. The COFFEE project (Calibration of Ocean Forcing with satellite Flux Estimates) endeavors to correct ocean forecast bias through a responsive error partition among surface heat flux and ocean dynamics sources. A suite of experiments in the southern California Current demonstrates a range of COFFEE capabilities, showing the impact on forecast error relative to a baseline three-dimensional variational (3DVAR) assimilation using Navy operational global or regional atmospheric forcing. COFFEE addresses satellite-calibration of surface fluxes to estimate surface error covariances and links these to the ocean interior. Experiment cases combine different levels of flux calibration with different assimilation alternatives. The cases may use the original fluxes, apply full satellite corrections during the forecast period, or extend hindcast corrections into the forecast period. Assimilation is either baseline 3DVAR or standard strong-constraint 4DVAR, with work proceeding to add a 4DVAR expanded to include a weak constraint treatment of the surface flux errors. Covariance of flux errors is estimated from the recent time series of forecast and calibrated flux terms. While the California Current examples are shown, the approach is equally applicable to other regions. These approaches within a 3DVAR application are anticipated to be useful for global and larger

  13. Genetically encoded pH sensor for tracking surface proteins through endocytosis.

    Science.gov (United States)

    Grover, Anmol; Schmidt, Brigitte F; Salter, Russell D; Watkins, Simon C; Waggoner, Alan S; Bruchez, Marcel P

    2012-05-14

    Traffic cam: a tandem dye prepared from a FRET acceptor and a fluorogenic donor functions as a cell surface ratiometric pH indicator, which upon internalization serves to follow protein trafficking during endocytosis. This sensor was used to analyze agonist-dependent internalization of β(2)-adrenergic receptors. It was also used as a surrogate antigen to reveal direct surface-to-endosome antigen transfer between dendritic cells (not shown). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Using the Regional Ocean Modelling System (ROMS to improve the sea surface temperature predictions of the MERCATOR Ocean System

    Directory of Open Access Journals (Sweden)

    Pedro Costa

    2012-09-01

    Full Text Available Global models are generally capable of reproducing the observed trends in the globally averaged sea surface temperature (SST. However, the global models do not perform as well on regional scales. Here, we present an ocean forecast system based on the Regional Ocean Modelling System (ROMS, the boundary conditions come from the MERCATOR ocean system for the North Atlantic (1/6° horizontal resolution. The system covers the region of the northwestern Iberian Peninsula with a horizontal resolution of 1/36°, forced with the Weather Research and Forecasting Model (WRF and the Soil Water Assessment Tool (SWAT. The ocean model results from the regional ocean model are validated using real-time SST and observations from the MeteoGalicia, INTECMAR and Puertos Del Estado real-time observational networks. The validation results reveal that over a one-year period the mean absolute error of the SST is less than 1°C, and several sources of measured data reveal that the errors decrease near the coast. This improvement is related to the inclusion of local forcing not present in the boundary condition model.

  15. Annual mean statistics of the surface fluxes of the tropical Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    RameshKumar, M.R.; Rao, L.V.G.

    MEAN STATISTICS OF THE SURFACE FLUXES OF THE TROPICAL INDIAN OCEAN (Research Note) M. R. RAMESH KUMAR and L. V. GANGADHARA RAO Physical Oceanography Division, National Institute of Oceanography, Dona Paula, 403004, Goa, India (Received in final...

  16. Extreme diving behaviour in devil rays links surface waters and the deep ocean

    KAUST Repository

    Thorrold, Simon R.; Afonso, Pedro; Fontes, Jorge; Braun, Camrin D.; Santos, Ricardo S.; Skomal, Gregory B.; Berumen, Michael L.

    2014-01-01

    Ecological connections between surface waters and the deep ocean remain poorly studied despite the high biomass of fishes and squids residing at depths beyond the euphotic zone. These animals likely support pelagic food webs containing a suite

  17. Influence of cutting data on surface quality when machining 17-4 PH stainless steel

    Science.gov (United States)

    Popovici, T. D.; Dijmărescu, M. R.

    2017-08-01

    The aim of the research presented in this paper is to analyse the cutting data influence upon surface quality for 17-4 PH stainless steel milling machining. The cutting regime parameters considered for the experiments were established using cutting regimes from experimental researches or from industrial conditions as basis, within the recommended ranges. The experimental program structure was determined by taking into account compatibility and orthogonality conditions, minimal use of material and labour. The machined surface roughness was determined by measuring the Ra roughness parameter, followed by surface profile registration in the form of graphics which were saved on a computer with MarSurf PS1Explorer software. Based on Ra roughness parameter, maximum values were extracted from these graphics and the influence charts of the cutting regime parameters upon surface roughness were traced using Microsoft Excel software. After a thorough analysis of the resulting data, relevant conclusions were drawn, presenting the interdependence between the surface roughness of the machined 17-4 PH samples and the cutting data variation.

  18. Pathways of upwelling deep waters to the surface of the Southern Ocean

    Science.gov (United States)

    Tamsitt, Veronica; Drake, Henri; Morrison, Adele; Talley, Lynne; Dufour, Carolina; Gray, Alison; Griffies, Stephen; Mazloff, Matthew; Sarmiento, Jorge; Wang, Jinbo; Weijer, Wilbert

    2017-04-01

    Upwelling of Atlantic, Indian and Pacific deep waters to the sea surface in the Southern Ocean closes the global overturning circulation and is fundamentally important for oceanic uptake of anthropogenic carbon and heat, nutrient resupply for sustaining oceanic biological production, and the melt rate of ice shelves. Here we go beyond the two-dimensional view of Southern Ocean upwelling, to show detailed Southern Ocean upwelling pathways in three dimensions, using hydrographic observations and particle tracking in high-resolution ocean and climate models. The northern deep waters enter the Antarctic Circumpolar Current (ACC) via narrow southward currents along the boundaries of the three ocean basins, before spiraling southeastward and upward through the ACC. Upwelling is greatly enhanced at five major topographic features, associated with vigorous mesoscale eddy activity. Deep water reaches the upper ocean predominantly south of the southern ACC boundary, with a spatially nonuniform distribution, regionalizing warm water supply to Antarctic ice shelves and the delivery of nutrient and carbon-rich water to the sea surface. The timescale for half of the deep water to upwell from 30°S to the mixed layer is on the order of 60-90 years, which has important implications for the timescale for signals to propagate through the deep ocean. In addition, we quantify the diabatic transformation along particle trajectories, to identify where diabatic processes are important along the upwelling pathways.

  19. Geochemistry of the Congo and Amazon river systems. Boron isotopic geochemistry in corals. Continental erosion and ocean pH

    International Nuclear Information System (INIS)

    Gaillardet, J.

    1995-01-01

    Two main geological processes control the CO 2 concentration in the atmosphere at a geological time scale: CO 2 outgasing from the interior of the Earth and CO 2 consumption by continental weathering. In the thesis, we initiate two different directions that can be useful to constraint the past climate evolution models. The first one is the extensive study of the largest rivers of the world using the classical geochemical analyses (major and trace elements, Sr-Nd-Pb isotopes) and modelling approaches. The study case of this thesis are the Congo and Amazon Basin. In particular, the coupling between chemical and physical erosion is examined and related to the hydrologic and tectonic parameters. Relief, thus tectonics appear to best control CO 2 consumption by rock weathering. The second part of the work is devoted to the measurement of boron isotopic ratio in corals because it may be used as a proxy for paleo-ocean pH. It could thus bring important pieces of information on the global C cycle and climate evolution. The technical part is extensively described and the method applied to the corals from the last interglacial period. Our conclusion is that corals are likely to be influence by early diagenetic changes that modify the boron isotopic composition of corals. We thus propose a test to select the samples. (author)

  20. Impact of including surface currents on simulation of Indian Ocean variability with the POAMA coupled model

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Mei; Wang, Guomin; Hendon, Harry H.; Alves, Oscar [Bureau of Meteorology, Centre for Australian Weather and Climate Research, Melbourne (Australia)

    2011-04-15

    Impacts on the coupled variability of the Indo-Pacific by including the effects of surface currents on surface stress are explored in four extended integrations of an experimental version of the Bureau of Meteorology's coupled seasonal forecast model POAMA. The first pair of simulations differs only in their treatment of momentum coupling: one version includes the effects of surface currents on the surface stress computation and the other does not. The version that includes the effect of surface currents has less mean-state bias in the equatorial Pacific cold tongue but produces relatively weak coupled variability in the Tropics, especially that related to the Indian Ocean dipole (IOD) and El Nino/Southern Oscillation (ENSO). The version without the effects of surface currents has greater bias in the Pacific cold tongue but stronger IOD and ENSO variability. In order to diagnose the role of changes in local coupling from changes in remote forcing by ENSO for causing changes in IOD variability, a second set of simulations is conducted where effects of surface currents are included only in the Indian Ocean and only in the Pacific Ocean. IOD variability is found to be equally reduced by inclusion of the local effects of surface currents in the Indian Ocean and by the reduction of ENSO variability as a result of including effects of surface currents in the Pacific. Some implications of these results for predictability of the IOD and its dependence on ENSO, and for ocean subsurface data assimilation are discussed. (orig.)

  1. Retrieval of sea surface velocities using sequential Ocean Colour

    Indian Academy of Sciences (India)

    The Indian remote sensing satellite, IRS-P4 (Oceansat-I) launched on May 26th, 1999 carried two sensors on board, i.e., the Ocean Colour Monitor (OCM) and the Multi-frequency Scanning Microwave Radiometer (MSMR) dedicated for oceanographic research. Sequential data of IRS-P4 OCM has been analysed over parts ...

  2. Sea surface salinity variability in the tropical Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Subrahmanyam, B; Murty, V.S.N.; Heffner, D.M.

    (EIO: 5 degrees S- 5 degrees N, 90 degrees-95 degrees E) and Southeastern Arabian Sea (SEAS: 5 degrees-9 degrees N, 72 degrees-76 degrees E) and to compare with the HYbrid Coordinate Ocean Model (HYCOM) simulated SSS for the period from January 2002...

  3. Influence of pH, bleaching agents, and acid etching on surface wear of bovine enamel

    Science.gov (United States)

    Soares, Ana Flávia; Bombonatti, Juliana Fraga Soares; Alencar, Marina Studart; Consolmagno, Elaine Cristina; Honório, Heitor Marques; Mondelli, Rafael Francisco Lia

    2016-01-01

    ABSTRACT Development of new materials for tooth bleaching justifies the need for studies to evaluate the changes in the enamel surface caused by different bleaching protocols. Objective The aim of this study was to evaluate the bovine dental enamel wear in function of different bleaching gel protocols, acid etching and pH variation. Material and Methods Sixty fragments of bovine teeth were cut, obtaining a control and test areas. In the test area, one half received etching followed by a bleaching gel application, and the other half, only the bleaching gel. The fragments were randomly divided into six groups (n=10), each one received one bleaching session with five hydrogen peroxide gel applications of 8 min, activated with hybrid light, diode laser/blue LED (HL) or diode laser/violet LED (VHL) (experimental): Control (C); 35% Total Blanc Office (TBO35HL); 35% Lase Peroxide Sensy (LPS35HL); 25% Lase Peroxide Sensy II (LPS25HL); 15% Lase Peroxide Lite (LPL15HL); and 10% hydrogen peroxide (experimental) (EXP10VHL). pH values were determined by a pHmeter at the initial and final time periods. Specimens were stored, subjected to simulated brushing cycles, and the superficial wear was determined (μm). ANOVA and Tukey´s tests were applied (α=0.05). Results The pH showed a slight decrease, except for Group LPL15HL. Group LPS25HL showed the highest degree of wear, with and without etching. Conclusion There was a decrease from the initial to the final pH. Different bleaching gels were able to increase the surface wear values after simulated brushing. Acid etching before bleaching increased surface wear values in all groups. PMID:27008254

  4. The Wave Glider°: A New Autonomous Surface Vehicle to Augment MBARI's Growing Fleet of Ocean Observing Systems

    Science.gov (United States)

    Tougher, B. B.

    2011-12-01

    Monterey Bay Aquarium Research Institute's (MBARI) evolving fleet of ocean observing systems has made it possible to collect information and data about a wide variety of ocean parameters, enabling researchers to better understand marine ecosystems. In collaboration with Liquid Robotics Inc, the designer of the Wave Glider autonomous surface vehicle (ASV), MBARI is adding a new capability to its suite of ocean observing tools. This new technology will augment MBARI research programs that use satellites, ships, moorings, drifters, autonomous underwater vehicles (AUVs) and remotely operated vehicles (ROVs) to improve data collection of temporally and spatially variable oceanographic features. The Wave Glider ASV derives its propulsion from wave energy, while sensors and communications are powered through the use of two solar panels and batteries, enabling it to remain at sea indefinitely. Wave Gliders are remotely controlled via real-time Iridium burst communications, which also permit real-time data telemetry. MBARI has developed Ocean Acidification (OA) moorings to continuously monitor the chemical and physical changes occurring in the ocean as a result of increased levels of atmospheric carbon dioxide (CO2). The moorings are spatially restricted by being anchored to the seafloor, so during the summer of 2011 the ocean acidification sensor suite designed for moorings was integrated into a Wave Glider ASV to increase both temporal and spatial ocean observation capabilities. The OA sensor package enables the measurement of parameters essential to better understanding the changing acidity of the ocean, specifically pCO2, pH, oxygen, salinity and temperature. The Wave Glider will also be equipped with a meteorological sensor suite that will measure air temperature, air pressure, and wind speed and direction. The OA sensor integration into a Wave Glider was part of MBARI's 2011 summer internship program. This project involved designing a new layout for the OA sensors

  5. PH sensor

    OpenAIRE

    Artero, C.; Nogueras Cervera, Marc; Manuel Lázaro, Antonio

    2012-01-01

    This paper presents a design of a marine instrument for the measurement of pH in seawater. The measurement system consists of a pH electrode connected to the underwater observatory OBSEA. The extracted data are useful for scientists researching ocean acidification. Peer Reviewed

  6. Surface chemistry of PH 3, PF 3 and PCl 3 on Ru(0001)

    Science.gov (United States)

    Tao, H.-S.; Diebold, U.; Shinn, N. D.; Madey, T. E.

    1994-06-01

    The adsorption, desorption and decomposition of PH 3, PF 3 and PCl 3 on Ru(0001) have been studied by soft X-ray photoelectron spectroscopy (SXPS) using synchrotron radiation. Due to large chemical shifts in the P 2p core levels, different phosphorus containing surface species can be identified. We find that PF 3 adsorbs molecularly on Ru(0001) at 80 and 300 K. At 80 K, PH 3 saturates the surface with one layer of atomic hydrogen, elemental phosphorus, subhydride (i.e., PHx (0 PH 3, with a total phosphorus coverage of 0.4 ML. At 300 K, PH 3 decomposes into atomic hydrogen and elemental phosphorus with a phosphorus coverage of 0.8 ML. At 80 K, PCl 3 adsorbs dissociatively into atomic chlorine, elemental phosphorus, PCl and possibly PCl 2 and PCl 3 in the first monolayer. Formation of multilayers of PCl 3 is observed at 80 K. At 300 K, PCl 3 adsorbs dissociatively as atomic chlorine and elemental phosphorus with a saturation phosphorus coverage of 0.1 ML. The variation in total phosphorus uptake at 300 K from PX3 ( X = H, FandCl) adsorption is a result of competition between site blocking by dissociation fragments and displacement reactions. Annealing surfaces with adsorbed phosphorus to 1000 K results in formation of RuzP ( z = 1 or 2), which is manifested by the chemical shifts in the P2p core level, as well as the P LVV Auger transition. The recombination of adsorbed phosphorus and adsorbed X ( = H, FandCl) from decomposition is also observed, but is a minor reaction channel on the surface. Thermochemical data are used to analyze the different stabilities of PX 3 at 300 K, namely, PF 3 adsorbs molecularly and PH 3 and PCl 3 dissociate completely. First, we compare the heat of molecular adsorption and the heat of dissociative adsorption of PX 3 on Ru(0001), using an enthalpy approach, and find results consistent with experimental observations. Second, we compare the total bond energy difference between molecular adsorption and complete dissociation of PX 3 on Ru

  7. Latitudinal and seasonal capacity of the surface oceans as a reservoir of polychlorinated biphenyls

    International Nuclear Information System (INIS)

    Jurado, Elena; Lohmann, Rainer; Meijer, Sandra; Jones, Kevin C.; Dachs, Jordi

    2004-01-01

    The oceans play an important role as a global reservoir and ultimate sink of persistent organic pollutants (POPs) such as polychlorinated biphenyls congeners (PCBs). However, the physical and biogeochemical variables that affect the oceanic capacity to retain PCBs show an important spatial and temporal variability which have not been studied in detail, so far. The objective of this paper is to assess the seasonal and spatial variability of the ocean's maximum capacity to act as a reservoir of atmospherically transported and deposited PCBs. A level I fugacity model is used which incorporates the environmental variables of temperature, phytoplankton biomass, and mixed layer depth, as determined from remote sensing and from climatological datasets. It is shown that temperature, phytoplankton biomass and mixed layer depth influence the potential PCB reservoir of the oceans, being phytoplankton biomass specially important in the oceanic productive regions. The ocean's maximum capacities to hold PCBs are estimated. They are compared to a budget of PCBs in the surface oceans derived using a level III model that assumes steady state and which incorporates water column settling fluxes as a loss process. Results suggest that settling fluxes will keep the surface oceanic reservoir of PCBs well below its maximum capacity, especially for the more hydrophobic compounds. The strong seasonal and latitudinal variability of the surface ocean's storage capacity needs further research, because it plays an important role in the global biogeochemical cycles controlling the ultimate sink of PCBs. Because this modeling exercise incorporates variations in downward fluxes driven by phytoplankton and the extent of the water column mixing, it predicts more complex latitudinal variations in PCBs concentrations than those previously suggested. - Model calculations estimate the latitudinal and seasonal storage capacity of the surface oceans for PCBs

  8. Effects of Sea-Surface Waves and Ocean Spray on Air-Sea Momentum Fluxes

    Science.gov (United States)

    Zhang, Ting; Song, Jinbao

    2018-04-01

    The effects of sea-surface waves and ocean spray on the marine atmospheric boundary layer (MABL) at different wind speeds and wave ages were investigated. An MABL model was developed that introduces a wave-induced component and spray force to the total surface stress. The theoretical model solution was determined assuming the eddy viscosity coefficient varied linearly with height above the sea surface. The wave-induced component was evaluated using a directional wave spectrum and growth rate. Spray force was described using interactions between ocean-spray droplets and wind-velocity shear. Wind profiles and sea-surface drag coefficients were calculated for low to high wind speeds for wind-generated sea at different wave ages to examine surface-wave and ocean-spray effects on MABL momentum distribution. The theoretical solutions were compared with model solutions neglecting wave-induced stress and/or spray stress. Surface waves strongly affected near-surface wind profiles and sea-surface drag coefficients at low to moderate wind speeds. Drag coefficients and near-surface wind speeds were lower for young than for old waves. At high wind speeds, ocean-spray droplets produced by wind-tearing breaking-wave crests affected the MABL strongly in comparison with surface waves, implying that wave age affects the MABL only negligibly. Low drag coefficients at high wind caused by ocean-spray production increased turbulent stress in the sea-spray generation layer, accelerating near-sea-surface wind. Comparing the analytical drag coefficient values with laboratory measurements and field observations indicated that surface waves and ocean spray significantly affect the MABL at different wind speeds and wave ages.

  9. Effect of Ocean Acidification and pH Fluctuations on the Growth and Development of Coralline Algal Recruits, and an Associated Benthic Algal Assemblage.

    Directory of Open Access Journals (Sweden)

    Michael Y Roleda

    Full Text Available Coralline algae are susceptible to the changes in the seawater carbonate system associated with ocean acidification (OA. However, the coastal environments in which corallines grow are subject to large daily pH fluctuations which may affect their responses to OA. Here, we followed the growth and development of the juvenile coralline alga Arthrocardia corymbosa, which had recruited into experimental conditions during a prior experiment, using a novel OA laboratory culture system to simulate the pH fluctuations observed within a kelp forest. Microscopic life history stages are considered more susceptible to environmental stress than adult stages; we compared the responses of newly recruited A. corymbosa to static and fluctuating seawater pH with those of their field-collected parents. Recruits were cultivated for 16 weeks under static pH 8.05 and 7.65, representing ambient and 4× preindustrial pCO2 concentrations, respectively, and two fluctuating pH treatments of daily [Formula: see text] (daytime pH = 8.45, night-time pH = 7.65 and daily [Formula: see text] (daytime pH = 8.05, night-time pH = 7.25. Positive growth rates of new recruits were recorded in all treatments, and were highest under static pH 8.05 and lowest under fluctuating pH 7.65. This pattern was similar to the adults' response, except that adults had zero growth under fluctuating pH 7.65. The % dry weight of MgCO3 in calcite of the juveniles was reduced from 10% at pH 8.05 to 8% at pH 7.65, but there was no effect of pH fluctuation. A wide range of fleshy macroalgae and at least 6 species of benthic diatoms recruited across all experimental treatments, from cryptic spores associated with the adult A. corymbosa. There was no effect of experimental treatment on the growth of the benthic diatoms. On the community level, pH-sensitive species may survive lower pH in the presence of diatoms and fleshy macroalgae, whose high metabolic activity may raise the pH of the local microhabitat.

  10. Effect of Ocean Acidification and pH Fluctuations on the Growth and Development of Coralline Algal Recruits, and an Associated Benthic Algal Assemblage

    Science.gov (United States)

    Roleda, Michael Y.; Cornwall, Christopher E.; Feng, Yuanyuan; McGraw, Christina M.; Smith, Abigail M.; Hurd, Catriona L.

    2015-01-01

    Coralline algae are susceptible to the changes in the seawater carbonate system associated with ocean acidification (OA). However, the coastal environments in which corallines grow are subject to large daily pH fluctuations which may affect their responses to OA. Here, we followed the growth and development of the juvenile coralline alga Arthrocardia corymbosa, which had recruited into experimental conditions during a prior experiment, using a novel OA laboratory culture system to simulate the pH fluctuations observed within a kelp forest. Microscopic life history stages are considered more susceptible to environmental stress than adult stages; we compared the responses of newly recruited A. corymbosa to static and fluctuating seawater pH with those of their field-collected parents. Recruits were cultivated for 16 weeks under static pH 8.05 and 7.65, representing ambient and 4× preindustrial pCO2 concentrations, respectively, and two fluctuating pH treatments of daily x~ = 8.05 (daytime pH = 8.45, night-time pH = 7.65) and daily x~ = 7.65 (daytime pH = 8.05, night-time pH = 7.25). Positive growth rates of new recruits were recorded in all treatments, and were highest under static pH 8.05 and lowest under fluctuating pH 7.65. This pattern was similar to the adults’ response, except that adults had zero growth under fluctuating pH 7.65. The % dry weight of MgCO3 in calcite of the juveniles was reduced from 10% at pH 8.05 to 8% at pH 7.65, but there was no effect of pH fluctuation. A wide range of fleshy macroalgae and at least 6 species of benthic diatoms recruited across all experimental treatments, from cryptic spores associated with the adult A. corymbosa. There was no effect of experimental treatment on the growth of the benthic diatoms. On the community level, pH-sensitive species may survive lower pH in the presence of diatoms and fleshy macroalgae, whose high metabolic activity may raise the pH of the local microhabitat. PMID:26469945

  11. Mapping Global Ocean Surface Albedo from Satellite Observations: Models, Algorithms, and Datasets

    Science.gov (United States)

    Li, X.; Fan, X.; Yan, H.; Li, A.; Wang, M.; Qu, Y.

    2018-04-01

    Ocean surface albedo (OSA) is one of the important parameters in surface radiation budget (SRB). It is usually considered as a controlling factor of the heat exchange among the atmosphere and ocean. The temporal and spatial dynamics of OSA determine the energy absorption of upper level ocean water, and have influences on the oceanic currents, atmospheric circulations, and transportation of material and energy of hydrosphere. Therefore, various parameterizations and models have been developed for describing the dynamics of OSA. However, it has been demonstrated that the currently available OSA datasets cannot full fill the requirement of global climate change studies. In this study, we present a literature review on mapping global OSA from satellite observations. The models (parameterizations, the coupled ocean-atmosphere radiative transfer (COART), and the three component ocean water albedo (TCOWA)), algorithms (the estimation method based on reanalysis data, and the direct-estimation algorithm), and datasets (the cloud, albedo and radiation (CLARA) surface albedo product, dataset derived by the TCOWA model, and the global land surface satellite (GLASS) phase-2 surface broadband albedo product) of OSA have been discussed, separately.

  12. Statistical fluctuations of an ocean surface inferred from shoes and ships

    Science.gov (United States)

    Lerche, Ian; Maubeuge, Frédéric

    1995-12-01

    This paper shows that it is possible to roughly estimate some ocean properties using simple time-dependent statistical models of ocean fluctuations. Based on a real incident, the loss by a vessel of a Nike shoes container in the North Pacific Ocean, a statistical model was tested on data sets consisting of the Nike shoes found by beachcombers a few months later. This statistical treatment of the shoes' motion allows one to infer velocity trends of the Pacific Ocean, together with their fluctuation strengths. The idea is to suppose that there is a mean bulk flow speed that can depend on location on the ocean surface and time. The fluctuations of the surface flow speed are then treated as statistically random. The distribution of shoes is described in space and time using Markov probability processes related to the mean and fluctuating ocean properties. The aim of the exercise is to provide some of the properties of the Pacific Ocean that are otherwise calculated using a sophisticated numerical model, OSCURS, where numerous data are needed. Relevant quantities are sharply estimated, which can be useful to (1) constrain output results from OSCURS computations, and (2) elucidate the behavior patterns of ocean flow characteristics on long time scales.

  13. Ocean Acidification in the Surface Waters of the Pacific-Arctic Boundary Regions

    Science.gov (United States)

    Mathis, J. T.; Cross, J. N.; Evans, W.; Doney, S. C.

    2016-02-01

    The continental shelves of the Pacific-Arctic Region (PAR) are especially vulnerable to the effects of ocean acidification (OA) because the intrusion of anthropogenic CO2 is not the only process that can reduce pH and carbonate mineral saturation states for aragonite (ΩArag). Enhanced sea-ice melt, respiration of organic matter, upwelling and riverine inputs have been shown to exacerbate CO2-driven ocean acidification in high-latitude regions. Additionally, the indirect effect of changing sea-ice coverage is providing a positive feedback to OA as more open water will allow for greater uptake of atmospheric CO2. Here, we compare model-based outputs from the Community Earth System Model with a subset of recent ship-based observations, and take an initial look at future model projections of surface water ΩArag in the Bering, Chukchi and Beaufort Seas. We then use the model outputs to define benchmark years when biological impacts are likely to result from reduced ΩArag. Each of the three continental shelf seas in the PAR will become undersaturated with respect to aragonite at approximately 30-year intervals, indicating that aragonite undersaturations gradually progress upstream along the flow path of the waters as they move north from the Pacific Ocean. However, naturally high variability in ΩArag may indicate higher resilience of the Bering Sea ecosystem to these low-ΩArag conditions than the Chukchi and the Beaufort Seas. Based on our initial results, we have determined that the annual mean for ΩArag will pass below the current range of natural variability in 2025 for the Beaufort Sea and 2027 for the Chukchi Sea. Because of the higher range of natural variability, the annual mean for ΩArag for the Bering Sea does not pass out of the natural variability range until 2044. As ΩArag in these shelf seas slips below the present-day range of large seasonal variability by midcentury, it could put tremendous pressure on the diverse ecosystems that support some of

  14. Trans-life cycle acclimation to experimental ocean acidification affects gastric pH homeostasis and larval recruitment in the sea star Asterias rubens.

    Science.gov (United States)

    Hu, Marian Y; Lein, Etienne; Bleich, Markus; Melzner, Frank; Stumpp, Meike

    2018-04-16

    Experimental simulation of near-future ocean acidification (OA) has been demonstrated to affect growth and development of echinoderm larval stages through energy allocation towards ion and pH compensatory processes. To date, it remains largely unknown how major pH regulatory systems and their energetics are affected by trans-generational exposure to near-future acidification levels. Here we used the common sea star Asterias rubens in a reciprocal transplant experiment comprising different combinations of OA scenarios, in order to study trans-generational plasticity using morphological and physiological endpoints. Acclimation of adults to pH T 7.2 (pCO 2 3500μatm) led to reductions in feeding rates, gonad weight, and fecundity. No effects were evident at moderate acidification levels (pH T 7.4; pCO 2 2000μatm). Parental pre-acclimation to pH T 7.2 for 85 days reduced developmental rates even when larvae were raised under moderate and high pH conditions, whereas pre-acclimation to pH T 7.4 did not alter offspring performance. Microelectrode measurements and pharmacological inhibitor studies carried out on larval stages demonstrated that maintenance of alkaline gastric pH represents a substantial energy sink under acidified conditions that may contribute up to 30% to the total energy budget. Parental pre-acclimation to acidification levels that are beyond the pH that is encountered by this population in its natural habitat (e.g. pH T 7.2) negatively affected larval size and development, potentially through reduced energy transfer. Maintenance of alkaline gastric pH and reductions in maternal energy reserves probably constitute the main factors for a reduced juvenile recruitment of this marine keystone species under simulated OA. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  15. pH and redox responsive polymer for antifouling surface coating

    International Nuclear Information System (INIS)

    Lee, Kang Seok; In, Insik; Park, Sung Young

    2014-01-01

    Graphical abstract: Dual responsive surface with highly fouling resistance with the formation of a pH-dependent benzoic imine and redox-sensitive disulfide bond has been developed using a catechol/benzoic acid conjugated polymer and disulfide containing amine end-capped Pluronic. - Highlights: • Stimuli-responsive antifouling surface was prepared by layer-by-layer method. • The surface contact angle showed responsive behavior via pH and redox environments. • Simply coated polymer completely prevented cell adhesion onto surfaces. - Abstract: A dual environmentally responsive polymer with a highly fouling-resistant surface has been developed using poly[(hydroxyethyl methacrylate-g-benzoic acid)-co-(dimethylaminoethyl methacrylate-g-2-chloro-3′, 4′-dihydroxyacetophenone)] [poly[(HEMA-BA)-co-(DMAEMA-CCDP)], P1] as a coating material. The redox-sensitive disulfide containing amine end-capped Pluronic [(Plu-S-S-NH 2 ), P2] was then introduced over the P1 surface via the formation of a pH-dependent benzoic imine bond, where the polyethylene glycol (PEG) acts as an antifouling agent. The successful adhesion of P1 and the deposition of P2 onto the P1-coated substrate were ascertained with X-ray photoelectron spectroscopy (XPS). In vitro cell adhesion followed by scanning electron microscopy (SEM) indicated an excellent antifouling nature of the P2 layer. Consequently, the reattachment of Hela cells was strongly observed when P2 layered on P1-coated substrates (P1–P2) was pretreated at lower pH and high redox conditions. The P1–P2 bilayer-coated substrate has exhibited a great advantage in its effective antifouling behaviors with well-tuned cell attachment and detachment

  16. pH and redox responsive polymer for antifouling surface coating

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kang Seok [Department of Chemical and Biological Engineering, Korea National University of Transportation, Chungju, 380-702 (Korea, Republic of); In, Insik, E-mail: in1@ut.ac.kr [Department of Polymer Science and Engineering, Korea National University of Transportation, Chungju, 380-702 (Korea, Republic of); Department of IT Convergence, Korea National University of Transportation, Chungju, 380-702 (Korea, Republic of); Park, Sung Young, E-mail: parkchem@ut.ac.kr [Department of Chemical and Biological Engineering, Korea National University of Transportation, Chungju, 380-702 (Korea, Republic of); Department of IT Convergence, Korea National University of Transportation, Chungju, 380-702 (Korea, Republic of)

    2014-09-15

    Graphical abstract: Dual responsive surface with highly fouling resistance with the formation of a pH-dependent benzoic imine and redox-sensitive disulfide bond has been developed using a catechol/benzoic acid conjugated polymer and disulfide containing amine end-capped Pluronic. - Highlights: • Stimuli-responsive antifouling surface was prepared by layer-by-layer method. • The surface contact angle showed responsive behavior via pH and redox environments. • Simply coated polymer completely prevented cell adhesion onto surfaces. - Abstract: A dual environmentally responsive polymer with a highly fouling-resistant surface has been developed using poly[(hydroxyethyl methacrylate-g-benzoic acid)-co-(dimethylaminoethyl methacrylate-g-2-chloro-3′, 4′-dihydroxyacetophenone)] [poly[(HEMA-BA)-co-(DMAEMA-CCDP)], P1] as a coating material. The redox-sensitive disulfide containing amine end-capped Pluronic [(Plu-S-S-NH{sub 2}), P2] was then introduced over the P1 surface via the formation of a pH-dependent benzoic imine bond, where the polyethylene glycol (PEG) acts as an antifouling agent. The successful adhesion of P1 and the deposition of P2 onto the P1-coated substrate were ascertained with X-ray photoelectron spectroscopy (XPS). In vitro cell adhesion followed by scanning electron microscopy (SEM) indicated an excellent antifouling nature of the P2 layer. Consequently, the reattachment of Hela cells was strongly observed when P2 layered on P1-coated substrates (P1–P2) was pretreated at lower pH and high redox conditions. The P1–P2 bilayer-coated substrate has exhibited a great advantage in its effective antifouling behaviors with well-tuned cell attachment and detachment.

  17. The Ocean's Vital Skin: Toward an Integrated Understanding of the Sea Surface Microlayer

    Directory of Open Access Journals (Sweden)

    Anja Engel

    2017-05-01

    Full Text Available Despite the huge extent of the ocean's surface, until now relatively little attention has been paid to the sea surface microlayer (SML as the ultimate interface where heat, momentum and mass exchange between the ocean and the atmosphere takes place. Via the SML, large-scale environmental changes in the ocean such as warming, acidification, deoxygenation, and eutrophication potentially influence cloud formation, precipitation, and the global radiation balance. Due to the deep connectivity between biological, chemical, and physical processes, studies of the SML may reveal multiple sensitivities to global and regional changes. Understanding the processes at the ocean's surface, in particular involving the SML as an important and determinant interface, could therefore provide an essential contribution to the reduction of uncertainties regarding ocean-climate feedbacks. This review identifies gaps in our current knowledge of the SML and highlights a need to develop a holistic and mechanistic understanding of the diverse biological, chemical, and physical processes occurring at the ocean-atmosphere interface. We advocate the development of strong interdisciplinary expertise and collaboration in order to bridge between ocean and atmospheric sciences. Although this will pose significant methodological challenges, such an initiative would represent a new role model for interdisciplinary research in Earth System sciences.

  18. Surface wave effects in the NEMO ocean model: Forced and coupled experiments

    Science.gov (United States)

    Breivik, Øyvind; Mogensen, Kristian; Bidlot, Jean-Raymond; Balmaseda, Magdalena Alonso; Janssen, Peter A. E. M.

    2015-04-01

    The NEMO general circulation ocean model is extended to incorporate three physical processes related to ocean surface waves, namely the surface stress (modified by growth and dissipation of the oceanic wavefield), the turbulent kinetic energy flux from breaking waves, and the Stokes-Coriolis force. Experiments are done with NEMO in ocean-only (forced) mode and coupled to the ECMWF atmospheric and wave models. Ocean-only integrations are forced with fields from the ERA-Interim reanalysis. All three effects are noticeable in the extratropics, but the sea-state-dependent turbulent kinetic energy flux yields by far the largest difference. This is partly because the control run has too vigorous deep mixing due to an empirical mixing term in NEMO. We investigate the relation between this ad hoc mixing and Langmuir turbulence and find that it is much more effective than the Langmuir parameterization used in NEMO. The biases in sea surface temperature as well as subsurface temperature are reduced, and the total ocean heat content exhibits a trend closer to that observed in a recent ocean reanalysis (ORAS4) when wave effects are included. Seasonal integrations of the coupled atmosphere-wave-ocean model consisting of NEMO, the wave model ECWAM, and the atmospheric model of ECMWF similarly show that the sea surface temperature biases are greatly reduced when the mixing is controlled by the sea state and properly weighted by the thickness of the uppermost level of the ocean model. These wave-related physical processes were recently implemented in the operational coupled ensemble forecast system of ECMWF.

  19. Ocean acidification affects parameters of immune response and extracellular pH in tropical sea urchins Lytechinus variegatus and Echinometra luccunter.

    Science.gov (United States)

    Leite Figueiredo, Débora Alvares; Branco, Paola Cristina; Dos Santos, Douglas Amaral; Emerenciano, Andrews Krupinski; Iunes, Renata Stecca; Shimada Borges, João Carlos; Machado Cunha da Silva, José Roberto

    2016-11-01

    The rising concentration of atmospheric CO 2 by anthropogenic activities is changing the chemistry of the oceans, resulting in a decreased pH. Several studies have shown that the decrease in pH can affect calcification rates and reproduction of marine invertebrates, but little attention has been drawn to their immune response. Thus this study evaluated in two adult tropical sea urchin species, Lytechinus variegatus and Echinometra lucunter, the effects of ocean acidification over a period of 24h and 5days, on parameters of the immune response, the extracellular acid base balance, and the ability to recover these parameters. For this reason, the phagocytic capacity (PC), the phagocytic index (PI), the capacity of cell adhesion, cell spreading, cell spreading area of phagocytic amebocytes in vitro, and the coelomic fluid pH were analyzed in animals exposed to a pH of 8.0 (control group), 7.6 and 7.3. Experimental pH's were predicted by IPCC for the future of the two species. Furthermore, a recovery test was conducted to verify whether animals have the ability to restore these physiological parameters after being re-exposed to control conditions. Both species presented a significant decrease in PC, in the pH of coelomic fluid and in the cell spreading area. Besides that, Echinometra lucunter showed a significant decrease in cell spreading and significant differences in coelomocyte proportions. The recovery test showed that the PC of both species increased, also being below the control values. Even so, they were still significantly higher than those exposed to acidified seawater, indicating that with the re-establishment of the pH value the phagocytic capacity of cells tends to restore control conditions. These results demonstrate that the immune system and the coelomic fluid pH of these animals can be affected by ocean acidification. However, the effects of a short-term exposure can be reversible if the natural values ​​are re-established. Thus, the effects of

  20. System for Monitoring, Determining, and Reporting Directional Spectra of Ocean Surface Waves in Near Realtime from a Moored Buoy

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A moored buoy floating at the ocean surface and anchored to the seafloor precisely measures acceleration, pitch, roll, and Earth's magnetic flux field of the buoy...

  1. Carbon dioxide from surface underway survey in global oceans from 1968 to 2006 (Version 1.0) (NODC Accession 0040205)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — More than 3 million measurements of surface water partial pressure of CO2 obtained over the global oceans during 1968 to 2006 are listed in the Lamont-Doherty Earth...

  2. Indian Ocean surface winds from NCMRWF analysis as compared to ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    The quality of the surface wind analysis at the National Centre for Medium Range Weather Fore- casts (NCMRWF), New .... mization of a generalized cost function using the. Spectral ... power from a given location on the sea surface at multiple ...

  3. Sea surface temperature predictions using a multi-ocean analysis ensemble scheme

    Science.gov (United States)

    Zhang, Ying; Zhu, Jieshun; Li, Zhongxian; Chen, Haishan; Zeng, Gang

    2017-08-01

    This study examined the global sea surface temperature (SST) predictions by a so-called multiple-ocean analysis ensemble (MAE) initialization method which was applied in the National Centers for Environmental Prediction (NCEP) Climate Forecast System Version 2 (CFSv2). Different from most operational climate prediction practices which are initialized by a specific ocean analysis system, the MAE method is based on multiple ocean analyses. In the paper, the MAE method was first justified by analyzing the ocean temperature variability in four ocean analyses which all are/were applied for operational climate predictions either at the European Centre for Medium-range Weather Forecasts or at NCEP. It was found that these systems exhibit substantial uncertainties in estimating the ocean states, especially at the deep layers. Further, a set of MAE hindcasts was conducted based on the four ocean analyses with CFSv2, starting from each April during 1982-2007. The MAE hindcasts were verified against a subset of hindcasts from the NCEP CFS Reanalysis and Reforecast (CFSRR) Project. Comparisons suggested that MAE shows better SST predictions than CFSRR over most regions where ocean dynamics plays a vital role in SST evolutions, such as the El Niño and Atlantic Niño regions. Furthermore, significant improvements were also found in summer precipitation predictions over the equatorial eastern Pacific and Atlantic oceans, for which the local SST prediction improvements should be responsible. The prediction improvements by MAE imply a problem for most current climate predictions which are based on a specific ocean analysis system. That is, their predictions would drift towards states biased by errors inherent in their ocean initialization system, and thus have large prediction errors. In contrast, MAE arguably has an advantage by sampling such structural uncertainties, and could efficiently cancel these errors out in their predictions.

  4. Vertical eddy diffusion as a key mechanism for removing perfluorooctanoic acid (PFOA) from the global surface oceans

    International Nuclear Information System (INIS)

    Lohmann, Rainer; Jurado, Elena; Dijkstra, Henk A.; Dachs, Jordi

    2013-01-01

    Here we estimate the importance of vertical eddy diffusion in removing perfluorooctanoic acid (PFOA) from the surface Ocean and assess its importance as a global sink. Measured water column profiles of PFOA were reproduced by assuming that vertical eddy diffusion in a 3-layer ocean model is the sole cause for the transport of PFOA to depth. The global oceanic sink due to eddy diffusion for PFOA is high, with accumulated removal fluxes over the last 40 years of 660 t, with the Atlantic Ocean accounting for 70% of the global oceanic sink. The global oceans have removed 13% of all PFOA produced to a depth greater than 100 m via vertical eddy diffusion; an additional 4% has been removed via deep water formation. The top 100 m of the surface oceans store another 21% of all PFOA produced (∼1100 t). Highlights: •Eddy diffusion has removed ∼660 t of PFOA from surface oceans over the last 40 years. •Atlantic Ocean accounts for 70% of the global oceanic sink of PFOA. •Vertical eddy diffusion has moved ∼13% of PFOA to oceans deeper than 100 m. •Around 4% of PFOA has been removed via deep water formation. •The top 100 m of global oceans contain ∼21% of historical PFOA production. -- Vertical eddy diffusion is an important removal process for hydrophilic organic pollutants such as PFOA from the surface ocean

  5. UV sensitivity of planktonic net community production in ocean surface waters

    OpenAIRE

    Regaudie de Gioux, Aurore; Agustí, Susana; Duarte, Carlos M.

    2014-01-01

    The net plankton community metabolism of oceanic surface waters is particularly important as it more directly affects the partial pressure of CO2 in surface waters and thus the air-sea fluxes of CO2. Plankton communities in surface waters are exposed to high irradiance that includes significant ultraviolet blue (UVB, 280-315 nm) radiation. UVB radiation affects both photosynthetic and respiration rates, increase plankton mortality rates, and other metabolic and chemical processes. Here we tes...

  6. Out of Thin Air: Microbial Utilization of Atmospheric Gaseous Organics in the Surface Ocean

    KAUST Repository

    Arrieta, J M; Duarte, Carlos M.; Sala, M. Montserrat; Dachs, Jordi

    2016-01-01

    Volatile and semi-volatile gas-phase organic carbon (GOC) is a largely neglected component of the global carbon cycle, with poorly resolved pools and fluxes of natural and anthropogenic GOC in the biosphere. Substantial amounts of atmospheric GOC are exchanged with the surface ocean, and subsequent utilization of specific GOC compounds by surface ocean microbial communities has been demonstrated. Yet, the final fate of the bulk of the atmospheric GOC entering the surface ocean is unknown. Our data show experimental evidence of efficient use of atmospheric GOC by marine prokaryotes at different locations in the NE Subtropical Atlantic, the Arctic Ocean and the Mediterranean Sea. We estimate that between 2 and 27% of the prokaryotic carbon demand was supported by GOC with a major fraction of GOC inputs being consumed within the mixed layer. The role of the atmosphere as a key vector of organic carbon subsidizing marine microbial metabolism is a novel link yet to be incorporated into the microbial ecology of the surface ocean as well as into the global carbon budget.

  7. Out of Thin Air: Microbial Utilization of Atmospheric Gaseous Organics in the Surface Ocean

    KAUST Repository

    Arrieta, Jesus

    2016-01-20

    Volatile and semi-volatile gas-phase organic carbon (GOC) is a largely neglected component of the global carbon cycle, with poorly resolved pools and fluxes of natural and anthropogenic GOC in the biosphere. Substantial amounts of atmospheric GOC are exchanged with the surface ocean, and subsequent utilization of specific GOC compounds by surface ocean microbial communities has been demonstrated. Yet, the final fate of the bulk of the atmospheric GOC entering the surface ocean is unknown. Our data show experimental evidence of efficient use of atmospheric GOC by marine prokaryotes at different locations in the NE Subtropical Atlantic, the Arctic Ocean and the Mediterranean Sea. We estimate that between 2 and 27% of the prokaryotic carbon demand was supported by GOC with a major fraction of GOC inputs being consumed within the mixed layer. The role of the atmosphere as a key vector of organic carbon subsidizing marine microbial metabolism is a novel link yet to be incorporated into the microbial ecology of the surface ocean as well as into the global carbon budget.

  8. Out of Thin Air: Microbial Utilization of Atmospheric Gaseous Organics in the Surface Ocean.

    Science.gov (United States)

    Arrieta, Jesús M; Duarte, Carlos M; Sala, M Montserrat; Dachs, Jordi

    2015-01-01

    Volatile and semi-volatile gas-phase organic carbon (GOC) is a largely neglected component of the global carbon cycle, with poorly resolved pools and fluxes of natural and anthropogenic GOC in the biosphere. Substantial amounts of atmospheric GOC are exchanged with the surface ocean, and subsequent utilization of specific GOC compounds by surface ocean microbial communities has been demonstrated. Yet, the final fate of the bulk of the atmospheric GOC entering the surface ocean is unknown. Our data show experimental evidence of efficient use of atmospheric GOC by marine prokaryotes at different locations in the NE Subtropical Atlantic, the Arctic Ocean and the Mediterranean Sea. We estimate that between 2 and 27% of the prokaryotic carbon demand was supported by GOC with a major fraction of GOC inputs being consumed within the mixed layer. The role of the atmosphere as a key vector of organic carbon subsidizing marine microbial metabolism is a novel link yet to be incorporated into the microbial ecology of the surface ocean as well as into the global carbon budget.

  9. Out of thin air: Microbial utilization of atmospheric gaseous organics in the surface ocean

    Directory of Open Access Journals (Sweden)

    Jesus M Arrieta

    2016-01-01

    Full Text Available Volatile and semi-volatile gas-phase organic carbon (GOC is a largely neglected component of the global carbon cycle, with poorly resolved pools and fluxes of natural and anthropogenic GOC in the biosphere. Substantial amounts of atmospheric GOC are exchanged with the surface ocean, and subsequent utilization of specific GOC compounds by surface ocean microbial communities has been demonstrated. Yet, the final fate of the bulk of the atmospheric GOC entering the surface ocean is unknown. Our data show experimental evidence of efficient use of atmospheric GOC by marine prokaryotes at different locations in the NE Subtropical Atlantic, the Arctic Ocean and the Mediterranean Sea. We estimate that between 2 to 27% of the prokaryotic carbon demand was supported by GOC with a major fraction of GOC inputs being consumed within the mixed layer. The role of the atmosphere as a key vector of organic carbon subsidising marine microbial metabolism is a novel link yet to be incorporated into the microbial ecology of the surface ocean as well as into the global carbon budget.

  10. Multi-mission mean sea surface and geoid models for ocean monitoring within the GOCINA project

    Science.gov (United States)

    Andersen, O. B.; Knudsen, P.; Anne, V. L.

    2004-05-01

    A major goal of the EU project GOCINA (Geoid and Ocean Circulation In the North Atlantic) is to develop tools for ocean monitoring using satellite altimetry combined with satellite gravimetry. Furthermore, the project will determine an accurate geoid in the region between Greenland and the UK and, hereby, create a platform for validation of future GOCE Level 2 data and higher order scientific products. The central quantity bridging the geoid and the ocean circulation is the mean dynamic topography, which is the difference between the mean sea surface and the geoid. The mean dynamic topography provides the absolute reference surface for the ocean circulation. The improved determination of the mean circulation will advance the understanding of the role of the ocean mass and heat transport in climate change. To calculate the best possible synthetic mean dynamic topographies a new mean sea surface (KMS03) has been derived from nine years of altimetric data (1993-2001). The regional geoid has furthermore being updated using GRACE and gravimetric data from a recent airborne survey. New synthetic mean dynamic topography models have been computed from the best available geoid models (EGM96, GRACE, GOCINA) and the present mean sea surface models (i.e. CLS01, GSFC00, KMS03). These models will be compared with state of the art hydrodynamic mean dynamic topography models in the North Atlantic GOCINA area. An extended comparison in the Artic Ocean will also be presented to demonstrate the impact of improved geoid and mean sea surface modeling. Particularly using the GRACE derived geoid models, and the KMS03 mean sea surface.

  11. Baseline monitoring of the western Arctic Ocean estimates 20% of the Canadian Basin surface waters are undersaturated with respect to aragonite

    Science.gov (United States)

    Robbins, Lisa L.; Wynn, Jonathan G.; Lisle, John T.; Yates, Kimberly K.; Knorr, Paul O.; Byrne, Robert H.; Liu, Xuewu; Patsavas, Mark C.; Azetsu-Scott, Kumiko; Takahashi, Taro

    2013-01-01

    Marine surface waters are being acidified due to uptake of anthropogenic carbon dioxide, resulting in surface ocean areas of undersaturation with respect to carbonate minerals, including aragonite. In the Arctic Ocean, acidification is expected to occur at an accelerated rate with respect to the global oceans, but a paucity of baseline data has limited our understanding of the extent of Arctic undersaturation and of regional variations in rates and causes. The lack of data has also hindered refinement of models aimed at projecting future trends of ocean acidification. Here, based on more than 34,000 data records collected in 2010 and 2011, we establish a baseline of inorganic carbon data (pH, total alkalinity, dissolved inorganic carbon, partial pressure of carbon dioxide, and aragonite saturation index) for the western Arctic Ocean. This data set documents aragonite undersaturation in ~20% of the surface waters of the combined Canada and Makarov basins, an area characterized by recent acceleration of sea ice loss. Conservative tracer studies using stable oxygen isotopic data from 307 sites show that while the entire surface of this area receives abundant freshwater from meteoric sources, freshwater from sea ice melt is most closely linked to the areas of carbonate mineral undersaturation. These data link the Arctic Ocean’s largest area of aragonite undersaturation to sea ice melt and atmospheric CO2 absorption in areas of low buffering capacity. Some relatively supersaturated areas can be linked to localized biological activity. Collectively, these observations can be used to project trends of ocean acidification in higher latitude marine surface waters where inorganic carbon chemistry is largely influenced by sea ice meltwater.

  12. Wave-Breaking Turbulence in the Ocean Surface Layer

    Science.gov (United States)

    2016-06-01

    2004) used direct numerical simulation ( DNS ) to show that a single breaking wave can energize the surface layer for more than 50 wave periods, and...1941: Dissipation of energy in the locally isotropic turbulence. Dokl. Akad. Nauk SSR, 30, 301–305. Kukulka, T., and K. Brunner, 2015: Passive

  13. Oceanic whitecaps: Sea surface features detectable via satellite that ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    experiments that the air-sea gas transfer coefficient for each of a wide range of gases, including carbon dioxide and .... generators with which the basin was equipped, the .... whitecaps in air-sea gas exchange; Gas Transfer at Water. Surfaces ...

  14. Intercomparison of oceanic and atmospheric forced and coupled mesoscale simulations. Part I: Surface fluxes

    Science.gov (United States)

    Josse, P.; Caniaux, G.; Giordani, H.; Planton, S.

    1999-04-01

    A mesoscale non-hydrostatic atmospheric model has been coupled with a mesoscale oceanic model. The case study is a four-day simulation of a strong storm event observed during the SEMAPHORE experiment over a 500 × 500 km2 domain. This domain encompasses a thermohaline front associated with the Azores current. In order to analyze the effect of mesoscale coupling, three simulations are compared: the first one with the atmospheric model forced by realistic sea surface temperature analyses; the second one with the ocean model forced by atmospheric fields, derived from weather forecast re-analyses; the third one with the models being coupled. For these three simulations the surface fluxes were computed with the same bulk parametrization. All three simulations succeed well in representing the main oceanic or atmospheric features observed during the storm. Comparison of surface fields with in situ observations reveals that the winds of the fine mesh atmospheric model are more realistic than those of the weather forecast re-analyses. The low-level winds simulated with the atmospheric model in the forced and coupled simulations are appreciably stronger than the re-analyzed winds. They also generate stronger fluxes. The coupled simulation has the strongest surface heat fluxes: the difference in the net heat budget with the oceanic forced simulation reaches on average 50 Wm-2 over the simulation period. Sea surface-temperature cooling is too weak in both simulations, but is improved in the coupled run and matches better the cooling observed with drifters. The spatial distributions of sea surface-temperature cooling and surface fluxes are strongly inhomogeneous over the simulation domain. The amplitude of the flux variation is maximum in the coupled run. Moreover the weak correlation between the cooling and heat flux patterns indicates that the surface fluxes are not responsible for the whole cooling and suggests that the response of the ocean mixed layer to the atmosphere is

  15. Helicopter-based lidar system for monitoring the upper ocean and terrain surface

    International Nuclear Information System (INIS)

    Lee, Kwi Joo; Park, Youngsik; Bunkin, Alexey; Pershin, Serguei; Voliak, Konstantin; Nunes, Raul

    2002-01-01

    A compact helicopter-based lidar system is developed and tested under laboratory and field conditions. It is shown that the lidar can measure concentrations of chlorophyll a and dissolved organic matter at the surface of water bodies, detect fluorescence spectra of ground vegetation at a distance of up to 530 m, and determine the vertical profile of light-scattering particle concentration in the upper ocean. The possibilities of the lidar system are demonstrated by detection of polluted areas at the ocean surface, by online monitoring of three-dimensional distribution of light-scattering layers, and by recognition of plant types and physiological states

  16. Spiraling pathways of global deep waters to the surface of the Southern Ocean.

    Science.gov (United States)

    Tamsitt, Veronica; Drake, Henri F; Morrison, Adele K; Talley, Lynne D; Dufour, Carolina O; Gray, Alison R; Griffies, Stephen M; Mazloff, Matthew R; Sarmiento, Jorge L; Wang, Jinbo; Weijer, Wilbert

    2017-08-02

    Upwelling of global deep waters to the sea surface in the Southern Ocean closes the global overturning circulation and is fundamentally important for oceanic uptake of carbon and heat, nutrient resupply for sustaining oceanic biological production, and the melt rate of ice shelves. However, the exact pathways and role of topography in Southern Ocean upwelling remain largely unknown. Here we show detailed upwelling pathways in three dimensions, using hydrographic observations and particle tracking in high-resolution models. The analysis reveals that the northern-sourced deep waters enter the Antarctic Circumpolar Current via southward flow along the boundaries of the three ocean basins, before spiraling southeastward and upward through the Antarctic Circumpolar Current. Upwelling is greatly enhanced at five major topographic features, associated with vigorous mesoscale eddy activity. Deep water reaches the upper ocean predominantly south of the Antarctic Circumpolar Current, with a spatially nonuniform distribution. The timescale for half of the deep water to upwell from 30° S to the mixed layer is ~60-90 years.Deep waters of the Atlantic, Pacific and Indian Oceans upwell in the Southern Oceanbut the exact pathways are not fully characterized. Here the authors present a three dimensional view showing a spiralling southward path, with enhanced upwelling by eddy-transport at topographic hotspots.

  17. SWOT: The Surface Water and Ocean Topography Mission. Wide- Swath Altimetric Elevation on Earth

    Science.gov (United States)

    Fu, Lee-Lueng (Editor); Alsdorf, Douglas (Editor); Morrow, Rosemary; Rodriguez, Ernesto; Mognard, Nelly

    2012-01-01

    The elevation of the surface of the ocean and freshwater bodies on land holds key information on many important processes of the Earth System. The elevation of the ocean surface, called ocean surface topography, has been measured by conventional nadirlooking radar altimeter for the past two decades. The data collected have been used for the study of large-scale circulation and sea level change. However, the spatial resolution of the observations has limited the study to scales larger than about 200 km, leaving the smaller scales containing substantial kinetic energy of ocean circulation that is responsible for the flux of heat, dissolved gas and nutrients between the upper and the deep ocean. This flux is important to the understanding of the ocean's role in regulatingfuture climate change.The elevation of the water bodies on land is a key parameter required for the computation of storage and discharge of freshwater in rivers, lakes, and wetlands. Globally, the spatial and temporal variability of water storage and discharge is poorly known due to the lack of well-sampled observations. In situ networks measuring river flows are declining worldwide due to economic and political reasons. Conventional altimeter observations suffers from the complexity of multiple peaks caused by the reflections from water, vegetation canopy and rough topography, resulting in much less valid data over land than over the ocean. Another major limitation is the large inter track distance preventing good coverage of rivers and other water bodies.This document provides descriptions of a new measurement technique using radar interferometry to obtain wide-swath measurement of water elevation at high resolution over both the ocean and land. Making this type of measurement, which addresses the shortcomings of conventional altimetry in both oceanographic and hydrologic applications, is the objective of a mission concept called Surface Water and Ocean Topography (SWOT), which was recommended by

  18. Sea surface temperature trends in the coastal ocean

    OpenAIRE

    Amos, C.L.; Al-Rashidi, Thamer B.; Rakha, Karim; El-Gamily, Hamdy; Nicholls, R.J.

    2013-01-01

    Sea surface temperature (SST) trends in the coastal zone are shown to be increasing at rates that exceed the global trends by up to an order of magnitude. This paper compiles some of the evidence of the trends published in the literature. The evidence suggests that urbanization in the coastal hinterland is having a direct effect on SST through increased temperatures of river and lake waters, as well as through heated run-off and thermal effluent discharges from coastal infrastructure. These l...

  19. Ocean surface waves in Hurricane Ike (2008) and Superstorm Sandy (2012): Coupled model predictions and observations

    Science.gov (United States)

    Chen, Shuyi S.; Curcic, Milan

    2016-07-01

    Forecasting hurricane impacts of extreme winds and flooding requires accurate prediction of hurricane structure and storm-induced ocean surface waves days in advance. The waves are complex, especially near landfall when the hurricane winds and water depth varies significantly and the surface waves refract, shoal and dissipate. In this study, we examine the spatial structure, magnitude, and directional spectrum of hurricane-induced ocean waves using a high resolution, fully coupled atmosphere-wave-ocean model and observations. The coupled model predictions of ocean surface waves in Hurricane Ike (2008) over the Gulf of Mexico and Superstorm Sandy (2012) in the northeastern Atlantic and coastal region are evaluated with the NDBC buoy and satellite altimeter observations. Although there are characteristics that are general to ocean waves in both hurricanes as documented in previous studies, wave fields in Ike and Sandy possess unique properties due mostly to the distinct wind fields and coastal bathymetry in the two storms. Several processes are found to significantly modulate hurricane surface waves near landfall. First, the phase speed and group velocities decrease as the waves become shorter and steeper in shallow water, effectively increasing surface roughness and wind stress. Second, the bottom-induced refraction acts to turn the waves toward the coast, increasing the misalignment between the wind and waves. Third, as the hurricane translates over land, the left side of the storm center is characterized by offshore winds over very short fetch, which opposes incoming swell. Landfalling hurricanes produce broader wave spectra overall than that of the open ocean. The front-left quadrant is most complex, where the combination of windsea, swell propagating against the wind, increasing wind-wave stress, and interaction with the coastal topography requires a fully coupled model to meet these challenges in hurricane wave and surge prediction.

  20. Climate change in the sea: the implications of increasing the carbon dioxide inputs to the surface ocean

    Energy Technology Data Exchange (ETDEWEB)

    Pfister, Cathy [University of Chicago

    2012-12-23

    The oceans are estimated to be absorbing one-third of the fossil fuel carbon released into the atmosphere, a process that is expected to change ocean carbon chemistry. I will present data from the Washington coast showing ocean pH declines and changes to the shell chemistry of bivalves. I will discuss implications of carbon cycle changes for marine species, including insights from a coastal area where I have worked for more than 24 years. I will summarize what we know to date about this process of “ocean acidification”.

  1. A small autonomous surface vehicle for ocean color remote sensing

    Digital Repository Service at National Institute of Oceanography (India)

    Desa, E.S.; Maurya, P.; Pereira, A.; Pascoal, A.M.; Desai, R.G.P.; Mascarenhas, A.A.M.Q.; Desa, E.; Madhan, R.; Matondkar, S.G.P.; Navelkar, G.S.; Prabhudesai, S.; Afzulpurkar, S.

    -assisted navigation and guidance using a conventional line-of-sight (LOS) strategy has been implemented on ROSS for different geometrical patterns of mission tracks. ROSS was then used at sea where it executed a square maneuver while measuring surface chlorophyll. A... described previously has been tested on the ASV using a VHF modem operating at 115 kb/s and has worked sat- isfactorily within a range of up to 5 km with both devices within line of sight (LOS). VI. ROSS MC PROGRAM ROSS can be controlled and programmed...

  2. Impulse exchange at the surface of the ocean and the fractal dimension of drifter trajectories

    Directory of Open Access Journals (Sweden)

    D. M. Summers

    2002-01-01

    Full Text Available An impulse-based model is developed to represent a coupling between turbulent flow in the atmosphere and turbulent flow in the ocean. In particular, it is argued that the atmosphere flowing horizontally over the ocean surface generates a velocity fluctuation field in the latter's near-surface flow. The mechanism for this can be understood kinematically in terms of an exchange of tangentially-oriented fluid impulse at the air-sea interface. We represent this exchange numerically through the creation of Lagrangian elements of impulse density. An indication of the efficacy of such a model would lie in its ability to predict the observed fractal dimension of lateral trajectories of submerged floats set adrift in the ocean. To this end, we examine the geometry of lateral tracer-paths determined from the present model.

  3. A pH dependent Raman and surface enhanced Raman spectroscopic studies of citrazinic acid aided by theoretical calculations

    Science.gov (United States)

    Sarkar, Sougata; Chowdhury, Joydeep; Dutta, Soumen; Pal, Tarasankar

    2016-12-01

    A pH dependent normal Raman scattering (NRS) and surface enhanced Raman scattering (SERS) spectral patterns of citrazinic acid (CZA), a biologically important molecule, have been investigated. The acid, with different pKa values ( 4 and 11) for the two different functional groups (-COOH and -OH groups), shows interesting range of color changes (yellow at pH 14 and brown at pH 2) with the variation in solution pH. Thus, depending upon the pH of the medium, CZA molecule can exist in various protonated and/or deprotonated forms. Here we have prescribed the existence different possible forms of CZA at different pH (Forms ;C;, ;H; and ;Dprot; at pH 14 and Forms ;A;, ;D;, and ;P; at pH 2 respectively). The NRS spectra of these solutions and their respective SERS spectra over gold nanoparticles were recorded. The spectra clearly differ in their spectral profiles. For example the SERS spectra recorded with the CZA solution at pH 2 shows blue shift for different bands compared to its NRS window e.g. 406 to 450 cm- 1, 616 to 632 cm- 1, 1332 to 1343 cm- 1 etc. Again, the most enhanced peak at 1548 cm- 1 in NRS while in the SERS window this appears at 1580 cm- 1. Similar observation was also made for CZA at pH 14. For example, the 423 cm- 1 band in the NRS profile experience a blue shift and appears at 447 cm- 1 in the SERS spectrum as well as other bands at 850, 1067 and 1214 cm- 1 in the SERS window are markedly enhanced. It is also worth noting that the SERS spectra at the different pH also differ from each other. These spectral differences indicate the existence of various adsorptive forms of the CZA molecule depending upon the pH of the solution. Therefore based on the experimental findings we propose different possible molecular forms of CZA at different pH (acidic and alkaline) conditions. For example forms 'A', 'D' and 'P' existing in acidic pH (pH 2) and three other deprotonated forms 'C', 'H' and 'Dprot' in alkaline pH (pH 14). The DFT calculations for these

  4. Binding of chloroquine to ionic micelles: Effect of pH and micellar surface charge

    Energy Technology Data Exchange (ETDEWEB)

    Souza Santos, Marcela de, E-mail: marcelafarmausp77@gmail.com [Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, s/n, Ribeirão Preto, São Paulo 14040-903 (Brazil); Perpétua Freire de Morais Del Lama, Maria, E-mail: mpemdel@fcfrp.usp.br [Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, s/n, Ribeirão Preto, São Paulo 14040-903 (Brazil); Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Departamento de Química Analítica, Universidade Estadual de Campinas, Cidade Universitária Zeferino Vaz, s/n, Campinas, São Paulo 13083-970 (Brazil); Siuiti Ito, Amando, E-mail: amandosi@ffclrp.usp.br [Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, São Paulo 14040-901 (Brazil); and others

    2014-03-15

    The pharmacological action of chloroquine relies on its ability to cross biological membranes in order to accumulate inside lysosomes. The present work aimed at understanding the basis for the interaction between different chloroquine species and ionic micelles of opposite charges, the latter used as a simple membrane model. The sensitivity of absorbance and fluorescence of chloroquine to changes in its local environment was used to probe its interaction with cetyltrimethylammonium micelles presenting bromide (CTAB) and sulfate (CTAS) as counterions, in addition to dodecyl sulfate micelles bearing sodium (SDS) and tetramethylammonium (TMADS) counterions. Counterion exchange was shown to have little effect on drug–micelle interaction. Chloroquine first dissociation constant (pKa{sub 1}) shifted to opposite directions when anionic and cationic micelles were compared. Chloroquine binding constants (K{sub b}) revealed that electrostatic forces mediate charged drug–micelle association, whereas hydrophobic interactions allowed neutral chloroquine to associate with anionic and cationic micelles. Fluorescence quenching studies indicated that monoprotonated chloroquine is inserted deeper into the micelle surface of anionic micelles than its neutral form, the latter being less exposed to the aqueous phase when associated with cationic over anionic assemblies. The findings provide further evidence that chloroquine–micelle interaction is driven by a tight interplay between the drug form and the micellar surface charge, which can have a major effect on the drug biological activity. -- Highlights: • Chloroquine (CQ) pKa{sub 1} increased for SDS micelles and decreased for CTAB micelles. • CQ is solubilized to the surface of both CTAB and SDS micelles. • Monoprotonated CQ is buried deeper into SDS micelles than neutral CQ. • Neutral CQ is less exposed to aqueous phase in CTAB over SDS micelles. • Local pH and micellar surface charge mediate interaction of CQ with

  5. Operational use of ocean surface drifters for tracking spilled oil

    International Nuclear Information System (INIS)

    Aamo, O. M.; Jensen, H.

    1997-01-01

    The use of Argos-positioned surface drifters by Norwegian engineers to monitor oil slicks in the North Sea was discussed. The system that was tested in June 1996 during the Norwegian Clean Seas Association oil-on-water exercise consisted of several GPS-positioned Argos drift trackers, an Argos receiver, a GPS navigator for the ship's position, and a PC with software for logging and displaying positions. Results of the field trial have been positive in that the system worked as expected. The range of direct transmission of signals from the buoys to the ship was about three nautical miles. The degree of accuracy of the relative positioning between the buoy GPS and the ship-borne GPS navigator was similar to the absolute positioning of single buoys. For best results, a minimum of two buoys and the use of lithium cells to increase battery capacity, were recommended. 3 refs., 5 figs

  6. Surface temperature of the equatorial Pacific Ocean and the Indian rainfall

    Digital Repository Service at National Institute of Oceanography (India)

    Gopinathan, C.K.

    The time variation of the monthly mean surface temperature of the equatorial Pacific Ocean during 1982-1987 has been studied in relation to summer monsoon rainfall over India The ENSO events of 1982 and 1987 were related to a significant reduction...

  7. Probing Earth’s conductivity structure beneath oceans by scalar geomagnetic data: autonomous surface vehicle solution

    DEFF Research Database (Denmark)

    Kuvshinov, Alexey; Matzka, Jürgen; Poedjono, Benny

    2016-01-01

    to the conductivity structure beneath the ocean. We conclude that the sensitivity, depending on the bathymetry gradient, is typically largest near the coast offshore. We show that such sea-surface marine induction surveys can be performed with the Wave Glider, an easy-to-deploy, autonomous, energy-harvesting floating...

  8. Spatio-temporal Variability in Surface Ocean pCO2 Inferred from Observations

    OpenAIRE

    Jones, Steve

    2012-01-01

    The variability of surface ocean pCO2 is examined on multiple spatial and temporal scales. Temporal autocorrelation analysis is used to examine pCO2 variability over multiple years. Spatial autocorrelation analysis describes pCO2 variability over multiple spatial scales. Spatial autocorrelation lengths range between

  9. The warmer the ocean surface, the shallower the mixed layer. How much of this is true?

    Science.gov (United States)

    Somavilla, R; González-Pola, C; Fernández-Diaz, J

    2017-09-01

    Ocean surface warming is commonly associated with a more stratified, less productive, and less oxygenated ocean. Such an assertion is mainly based on consistent projections of increased near-surface stratification and shallower mixed layers under global warming scenarios. However, while the observed sea surface temperature (SST) is rising at midlatitudes, the concurrent ocean record shows that stratification is not unequivocally increasing nor is MLD shoaling. We find that while SST increases at three study areas at midlatitudes, stratification both increases and decreases, and MLD deepens with enhanced deepening of winter MLDs at rates over 10 m  decade-1. These results rely on the estimation of several MLD and stratification indexes of different complexity on hydrographic profiles from long-term hydrographic time-series, ocean reanalysis, and Argo floats. Combining this information with estimated MLDs from buoyancy fluxes and the enhanced deepening/attenuation of the winter MLD trends due to changes in the Ekman pumping, MLD variability involves a subtle interplay between circulation and atmospheric forcing at midlatitudes. Besides, it is highlighted that the density difference between the surface and 200 m, the most widely used stratification index, should not be expected to reliably inform about changes in the vertical extent of mixing.

  10. Photo-oxidation: Major sink of oxygen in the ocean surface layer

    NARCIS (Netherlands)

    Gieskes, W.W.C.; Laane, R.W.P.M.; Ruardij, P.

    2015-01-01

    Evidence is presented that the oxygen demand associated with photochemical processes in the surface layer of oceans and seas worldwide is of the same order of magnitude as the amount of oxygen released by photosynthesis of the world's marine phytoplankton. Both estimates are of necessity quite rough

  11. Photo-oxidation : Major sink of oxygen in the ocean surface layer

    NARCIS (Netherlands)

    Gieskes, W. W. C.; Laane, R. W. P. M.; Ruardij, P.

    2015-01-01

    Evidence is presented that the oxygen demand associated with photochemical processes in the surface layer of oceans and seas worldwide is of the same order of magnitude as the amount of oxygen released by photosynthesis of the world's marine phytoplankton. Both estimates are of necessity quite rough

  12. Surface currents in the Bohai Sea derived from the Korean Geostationary Ocean Color Imager (GOCI)

    Science.gov (United States)

    Jiang, L.; Wang, M.

    2016-02-01

    The first geostationary ocean color satellite sensor, the Geostationary Ocean Color Imager (GOCI) onboard the Korean Communication, Ocean, and Meteorological Satellite can monitor and measure ocean phenomena over an area of 2500 × 2500 km2 around the western Pacific region centered at 36°N and 130°E. Hourly measurements during the day around 9:00 to 16:00 local time are a unique capability of GOCI to monitor ocean features of higher temporal variability. In this presentation, we show some recent results of GOCI-derived ocean surface currents in the Bohai Sea using the Maximum Cross-Correlation (MCC) feature tracking method and compare the results with altimetry-inversed tidal current observations produced from Oregon State University (OSU) Tidal Inversion Software (OTIS). The performance of the GOCI-based MCC method is assessed and the discrepancies between the GOCI- and OTIS-derived currents are evaluated. A series of sensitivity studies are conducted with images from various satellite products and of various time differences, MCC adjustable parameters, and influence from other forcings such as wind, to find the best setups for optimal MCC performance. Our results demonstrate that GOCI can effectively provide real-time monitoring of not only water optical, biological, and biogeochemical variability, but also the physical dynamics in the region.

  13. UV sensitivity of planktonic net community production in ocean surface waters

    Science.gov (United States)

    Regaudie-de-Gioux, Aurore; Agustí, Susana; Duarte, Carlos M.

    2014-05-01

    The net plankton community metabolism of oceanic surface waters is particularly important as it more directly affects the partial pressure of CO2 in surface waters and thus the air-sea fluxes of CO2. Plankton communities in surface waters are exposed to high irradiance that includes significant ultraviolet blue (UVB, 280-315 nm) radiation. UVB radiation affects both photosynthetic and respiration rates, increase plankton mortality rates, and other metabolic and chemical processes. Here we test the sensitivity of net community production (NCP) to UVB of planktonic communities in surface waters across contrasting regions of the ocean. We observed here that UVB radiation affects net plankton community production at the ocean surface, imposing a shift in NCP by, on average, 50% relative to the values measured when excluding partly UVB. Our results show that under full solar radiation, the metabolic balance shows the prevalence of net heterotrophic community production. The demonstration of an important effect of UVB radiation on NCP in surface waters presented here is of particular relevance in relation to the increased UVB radiation derived from the erosion of the stratospheric ozone layer. Our results encourage design future research to further our understanding of UVB effects on the metabolic balance of plankton communities.

  14. Ikaite crystals in melting sea ice - implications for pCO2 and pH levels in Arctic surface waters

    Science.gov (United States)

    Rysgaard, S.; Glud, R. N.; Lennert, K.; Cooper, M.; Halden, N.; Leakey, R. J. G.; Hawthorne, F. C.; Barber, D.

    2012-08-01

    A major issue of Arctic marine science is to understand whether the Arctic Ocean is, or will be, a source or sink for air-sea CO2 exchange. This has been complicated by the recent discoveries of ikaite (a polymorph of CaCO3·6H2O) in Arctic and Antarctic sea ice, which indicate that multiple chemical transformations occur in sea ice with a possible effect on CO2 and pH conditions in surface waters. Here, we report on biogeochemical conditions, microscopic examinations and x-ray diffraction analysis of single crystals from a melting 1.7 km2 (0.5-1 m thick) drifting ice floe in the Fram Strait during summer. Our findings show that ikaite crystals are present throughout the sea ice but with larger crystals appearing in the upper ice layers. Ikaite crystals placed at elevated temperatures disintegrated into smaller crystallites and dissolved. During our field campaign in late June, melt reduced the ice floe thickness by 0.2 m per week and resulted in an estimated 3.8 ppm decrease of pCO2 in the ocean surface mixed layer. This corresponds to an air-sea CO2 uptake of 10.6 mmol m-2 sea ice d-1 or to 3.3 ton km-2 ice floe week-1. This is markedly higher than the estimated primary production within the ice floe of 0.3-1.3 mmol m-2 sea ice d-1. Finally, the presence of ikaite in sea ice and the dissolution of the mineral during melting of the sea ice and mixing of the melt water into the surface oceanic mixed layer accounted for half of the estimated pCO2 uptake.

  15. Ikaite crystals in melting sea ice – implications for pCO2 and pH levels in Arctic surface waters

    Directory of Open Access Journals (Sweden)

    R. J. G. Leakey

    2012-08-01

    Full Text Available A major issue of Arctic marine science is to understand whether the Arctic Ocean is, or will be, a source or sink for air–sea CO2 exchange. This has been complicated by the recent discoveries of ikaite (a polymorph of CaCO3·6H2O in Arctic and Antarctic sea ice, which indicate that multiple chemical transformations occur in sea ice with a possible effect on CO2 and pH conditions in surface waters. Here, we report on biogeochemical conditions, microscopic examinations and x-ray diffraction analysis of single crystals from a melting 1.7 km2 (0.5–1 m thick drifting ice floe in the Fram Strait during summer. Our findings show that ikaite crystals are present throughout the sea ice but with larger crystals appearing in the upper ice layers. Ikaite crystals placed at elevated temperatures disintegrated into smaller crystallites and dissolved. During our field campaign in late June, melt reduced the ice floe thickness by 0.2 m per week and resulted in an estimated 3.8 ppm decrease of pCO2 in the ocean surface mixed layer. This corresponds to an air–sea CO2 uptake of 10.6 mmol m−2 sea ice d−1 or to 3.3 ton km−2 ice floe week−1. This is markedly higher than the estimated primary production within the ice floe of 0.3–1.3 mmol m−2 sea ice d−1. Finally, the presence of ikaite in sea ice and the dissolution of the mineral during melting of the sea ice and mixing of the melt water into the surface oceanic mixed layer accounted for half of the estimated pCO2 uptake.

  16. Engaging the Applications Community of the future Surface Water and Ocean Topography (SWOT) Mission

    Science.gov (United States)

    Srinivasan, M.; Andral, A.; Dejus, M.; Hossain, F.; Peterson, C.; Beighley, E.; Pavelsky, T.; Chao, Y.; Doorn, B.; Bronner, E.; Houpert, L.

    2015-04-01

    NASA and the French space agency, CNES, with contributions from the Canadian Space Agency (CSA) and United Kingdom Space Agency (UKSA) are developing new wide swath altimetry technology that will cover most of the world's ocean and surface freshwater bodies. The proposed Surface Water and Ocean Topography (SWOT) mission will have the capability to make observations of surface water (lakes, rivers, wetland) heights and measurements of ocean surface topography with unprecedented spatial coverage, temporal sampling, and spatial resolution compared to existing technologies. These data will be useful for monitoring the hydrologic cycle, flooding, and characterizing human impacts on a changing environment. The applied science community is a key element in the success of the SWOT mission, demonstrating the high value of the science and data products in addressing societal issues and needs. The SWOT applications framework includes a working group made up of applications specialists, SWOT science team members, academics and SWOT Project members to promote applications research and engage a broad community of potential SWOT data users. A defined plan and a guide describing a program to engage early adopters in using proxies for SWOT data, including sophisticated ocean and hydrology simulators, an airborne analogue for SWOT (AirSWOT), and existing satellite datasets, are cornerstones for the program. A user survey is in development and the first user workshop was held in 2015, with annual workshops planned. The anticipated science and engineering advances that SWOT will provide can be transformed into valuable services to decision makers and civic organizations focused on addressing global disaster risk reduction initiatives and potential science-based mitigation activities for water resources challenges of the future. With the surface water measurements anticipated from SWOT, a broad range of applications can inform inland and coastal managers and marine operators of

  17. Global relationships of total alkalinity with salinity and temperature in surface waters of the world's oceans. (NCEI Accession 0157795)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Surface Total Alkalinity fields were estimated from five regional TA relationships presented in Lee et al. 2006, using monthly mean sea surface temperature and...

  18. Intercomparison of oceanic and atmospheric forced and coupled mesoscale simulations Part I: Surface fluxes

    Directory of Open Access Journals (Sweden)

    P. Josse

    1999-04-01

    Full Text Available A mesoscale non-hydrostatic atmospheric model has been coupled with a mesoscale oceanic model. The case study is a four-day simulation of a strong storm event observed during the SEMAPHORE experiment over a 500 × 500 km2 domain. This domain encompasses a thermohaline front associated with the Azores current. In order to analyze the effect of mesoscale coupling, three simulations are compared: the first one with the atmospheric model forced by realistic sea surface temperature analyses; the second one with the ocean model forced by atmospheric fields, derived from weather forecast re-analyses; the third one with the models being coupled. For these three simulations the surface fluxes were computed with the same bulk parametrization. All three simulations succeed well in representing the main oceanic or atmospheric features observed during the storm. Comparison of surface fields with in situ observations reveals that the winds of the fine mesh atmospheric model are more realistic than those of the weather forecast re-analyses. The low-level winds simulated with the atmospheric model in the forced and coupled simulations are appreciably stronger than the re-analyzed winds. They also generate stronger fluxes. The coupled simulation has the strongest surface heat fluxes: the difference in the net heat budget with the oceanic forced simulation reaches on average 50 Wm-2 over the simulation period. Sea surface-temperature cooling is too weak in both simulations, but is improved in the coupled run and matches better the cooling observed with drifters. The spatial distributions of sea surface-temperature cooling and surface fluxes are strongly inhomogeneous over the simulation domain. The amplitude of the flux variation is maximum in the coupled run. Moreover the weak correlation between the cooling and heat flux patterns indicates that the surface fluxes are not responsible for the whole cooling and suggests that the response of the ocean mixed layer

  19. Intercomparison of oceanic and atmospheric forced and coupled mesoscale simulations Part I: Surface fluxes

    Directory of Open Access Journals (Sweden)

    H. Giordani

    Full Text Available A mesoscale non-hydrostatic atmospheric model has been coupled with a mesoscale oceanic model. The case study is a four-day simulation of a strong storm event observed during the SEMAPHORE experiment over a 500 × 500 km2 domain. This domain encompasses a thermohaline front associated with the Azores current. In order to analyze the effect of mesoscale coupling, three simulations are compared: the first one with the atmospheric model forced by realistic sea surface temperature analyses; the second one with the ocean model forced by atmospheric fields, derived from weather forecast re-analyses; the third one with the models being coupled. For these three simulations the surface fluxes were computed with the same bulk parametrization. All three simulations succeed well in representing the main oceanic or atmospheric features observed during the storm. Comparison of surface fields with in situ observations reveals that the winds of the fine mesh atmospheric model are more realistic than those of the weather forecast re-analyses. The low-level winds simulated with the atmospheric model in the forced and coupled simulations are appreciably stronger than the re-analyzed winds. They also generate stronger fluxes. The coupled simulation has the strongest surface heat fluxes: the difference in the net heat budget with the oceanic forced simulation reaches on average 50 Wm-2 over the simulation period. Sea surface-temperature cooling is too weak in both simulations, but is improved in the coupled run and matches better the cooling observed with drifters. The spatial distributions of sea surface-temperature cooling and surface fluxes are strongly inhomogeneous over the simulation domain. The amplitude of the flux variation is maximum in the coupled run. Moreover the weak correlation between the cooling and heat flux patterns indicates that the surface fluxes are not responsible for the whole cooling and suggests that the response of the ocean mixed layer

  20. Investigation of pH response and photo-control of wettability on spiropyran-derivatized surfaces

    Science.gov (United States)

    Park, Choong-Do

    2009-12-01

    One promising method to control a liquid drop on a surface for microfluidic devices is to use the surface tension gradient on a photo-responsive surface by light irradiation. A photo-switchable spiropyran monolayer was prepared on smooth glass or silicon wafers via 3-aminopropylmethyldiethoxysilane linkages. The pH response of the surface-bound spiropyran was investigated by measuring contact angle as a function of pH, since the pH value of the liquids applied to a microfluidic system can vary widely. Based on the contact angle titration and UV-Vis spectroscopic data, a protonation and deprotonation mechanism of the surface-bound spiropyran was proposed. The advancing contact angles under UV and under visible light irradiation at high pH values were about 100 smaller than those at low pH values. The decrease in contact angle under UV light with decreasing pH value was assigned to the protonation of open merocyanine (MC) to MC-OH+. Meanwhile, the decrease in contact angle under visible light was attributed to the protonation of the closed spiropryan (SP), generating a mixed state of MC-OH+ in equilibrium with N-protonated SP-NH+. In order to examine the possibility of light-induced liquid drop motion on the spiropyran-derivatized smooth surfaces, the light-induced surface tension change between SP and MC was estimated using the contact angle hysteresis (CAH) and the Lifshitz---van der Waals/Acid-Base (LWAB) approaches based on the contact angle data. The average light-induced surface energy change between the two isomers under UV and visible light exposure was 1.4 mJ/m 2, implying that the small change in surface tension is not sufficient to move a liquid droplet on the surface. Liquid drop motion requires that the light-induced switching angle be greater than the contact angle hysteresis. However, the light-induced switching angle of the spiropyran-derivatized surface was significantly smaller than the hysteresis. Thus, in order to achieve liquid drop motion on the

  1. Ocean Heat Uptake Slows 21st Century Surface Warming Driven by Extratropical Cloud Feedbacks

    Science.gov (United States)

    Frey, W.; Maroon, E.; Pendergrass, A. G.; Kay, J. E.

    2017-12-01

    Equilibrium climate sensitivity (ECS), the warming in response to instantaneously doubled CO2, has long been used to compare climate models. In many models, ECS is well correlated with warming produced by transient forcing experiments. Modifications to cloud phase at high latitudes in a state-of-the-art climate model, the Community Earth System Model (CESM), produce a large increase in ECS (1.5 K) via extratropical cloud feedbacks. However, only a small surface warming increase occurs in a realistic 21st century simulation including a full-depth dynamic ocean and the "business as usual" RCP8.5 emissions scenario. In fact, the increase in surface warming is only barely above the internal variability-generated range in the CESM Large Ensemble. The small change in 21st century warming is attributed to subpolar ocean heat uptake in both hemispheres. In the Southern Ocean, the mean-state circulation takes up heat while in the North Atlantic a slowdown in circulation acts as a feedback to slow surface warming. These results show the importance of subpolar ocean heat uptake in controlling the pace of warming and demonstrate that ECS cannot be used to reliably infer transient warming when it is driven by extratropical feedbacks.

  2. Origin, dynamics and evolution of ocean garbage patches from observed surface drifters

    International Nuclear Information System (INIS)

    Van Sebille, Erik; England, Matthew H; Froyland, Gary

    2012-01-01

    Much of the debris in the near-surface ocean collects in so-called garbage patches where, due to convergence of the surface flow, the debris is trapped for decades to millennia. Until now, studies modelling the pathways of surface marine debris have not included release from coasts or factored in the possibilities that release concentrations vary with region or that pathways may include seasonal cycles. Here, we use observational data from the Global Drifter Program in a particle-trajectory tracer approach that includes the seasonal cycle to study the fate of marine debris in the open ocean from coastal regions around the world on interannual to centennial timescales. We find that six major garbage patches emerge, one in each of the five subtropical basins and one previously unreported patch in the Barents Sea. The evolution of each of the six patches is markedly different. With the exception of the North Pacific, all patches are much more dispersive than expected from linear ocean circulation theory, suggesting that on centennial timescales the different basins are much better connected than previously thought and that inter-ocean exchanges play a large role in the spreading of marine debris. This study suggests that, over multi-millennial timescales, a significant amount of the debris released outside of the North Atlantic will eventually end up in the North Pacific patch, the main attractor of global marine debris. (letter)

  3. Arctic Sea Ice Basal Melt Onset Variability and Associated Ocean Surface Heating

    Science.gov (United States)

    Merrick, R. A.; Hutchings, J. K.

    2015-12-01

    The interannual and regional variability in Arctic sea ice melt has previously been characterized only in terms of surface melting. A focus on the variability in the onset of basal melt is additionally required to understand Arctic melt patterns. Monitoring basal melt provides a glimpse into the importance of ocean heating to sea ice melt. This warming is predominantly through seawater exposure due to lead opening and the associated solar warming at the ocean's surface. We present the temporal variability in basal melt onset observed by ice mass balance buoys throughout the Arctic Ocean since 2003, providing a different perspective than the satellite microwave data used to measure the onset of surface melt. We found that melt onset varies greatly, even for buoys deployed within 100km of each other. Therefore large volumes of data are necessary to accurately estimate the variability of basal melt onset. Once the variability of basal melt onset has been identified, we can investigate how this range has been changing as a response to atmospheric and oceanic warming, changes in ice morphology as well as the intensification of the ice albedo feedback.

  4. Extreme diving behaviour in devil rays links surface waters and the deep ocean

    KAUST Repository

    Thorrold, Simon R.

    2014-07-01

    Ecological connections between surface waters and the deep ocean remain poorly studied despite the high biomass of fishes and squids residing at depths beyond the euphotic zone. These animals likely support pelagic food webs containing a suite of predators that include commercially important fishes and marine mammals. Here we deploy pop-up satellite archival transmitting tags on 15 Chilean devil rays (Mobula tarapacana) in the central North Atlantic Ocean, which provide movement patterns of individuals for up to 9 months. Devil rays were considered surface dwellers but our data reveal individuals descending at speeds up to 6.0 ms-1 to depths of almost 2,000 m and water temperatures <4 C. The shape of the dive profiles suggests that the rays are foraging at these depths in deep scattering layers. Our results provide evidence of an important link between predators in the surface ocean and forage species occupying pelagic habitats below the euphotic zone in ocean ecosystems. 2014 Macmillan Publishers Limited. All rights reserved.

  5. Influence of molecular weight and pH on adsorption of chitosan at the surface of large and giant vesicles.

    Science.gov (United States)

    Quemeneur, Francois; Rinaudo, Marguerite; Pépin-Donat, Brigitte

    2008-01-01

    This paper describes the mechanisms of adsorption of chitosan, a positively charged polyelectrolyte, on the DOPC lipid membrane of large and giant unilamellar vesicles (respectively, LUVs and GUVs). We observe that the variation of the zeta potential of LUVs as a function of chitosan concentration is independent on the chitosan molecular weight (Mw). This result is interpreted in terms of electrostatic interactions, which induce a flat adsorption of the chitosan on the surface of the membrane. The role of electrostatic interactions is further studied by observing the variation of the zeta potential as a function of the chitosan concentration for two different charge densities tuned by the pH. Results show a stronger chitosan-membrane affinity at pH 6 (lipids are negatively charged, and 40% chitosan amino groups are protonated) than at pH 3.4 (100% of protonated amino groups but zwitterionic lipids are positively charged) which confirms that adsorption is of electrostatic origin. Then, we investigate the stability of decorated LUVs and GUVs in a large range of pH (6.0 pH variation of the zeta potential as a function of the pH (2.0 pH pH pH > 10.0, in the absence of chitosan, the vesicles present complex shapes, contrary to the chitosan-decorated vesicles which remain spherical, confirming thus that chitosan remains adsorbed on vesicles in basic conditions up to pH = 12.0. These results, in addition with our previous data, show that the chitosan-decorated vesicles are stable over a very broad range of pH (2.0 pH < 12.0), which holds promise for their in vivo applications. Finally, the quantification of the chitosan adsorption on a LUV membrane is performed by zeta potential and fluorescence measurements. The fraction of membrane surface covered by chitosan is estimated to be lower than 40 %, which corresponds to the formation of a flat layer of chitosan on the membrane surface on an electrostatic basis.

  6. Aerosol indirect effects on the nighttime Arctic Ocean surface from thin, predominantly liquid clouds

    Directory of Open Access Journals (Sweden)

    L. M. Zamora

    2017-06-01

    Full Text Available Aerosol indirect effects have potentially large impacts on the Arctic Ocean surface energy budget, but model estimates of regional-scale aerosol indirect effects are highly uncertain and poorly validated by observations. Here we demonstrate a new way to quantitatively estimate aerosol indirect effects on a regional scale from remote sensing observations. In this study, we focus on nighttime, optically thin, predominantly liquid clouds. The method is based on differences in cloud physical and microphysical characteristics in carefully selected clean, average, and aerosol-impacted conditions. The cloud subset of focus covers just ∼ 5 % of cloudy Arctic Ocean regions, warming the Arctic Ocean surface by ∼ 1–1.4 W m−2 regionally during polar night. However, within this cloud subset, aerosol and cloud conditions can be determined with high confidence using CALIPSO and CloudSat data and model output. This cloud subset is generally susceptible to aerosols, with a polar nighttime estimated maximum regionally integrated indirect cooling effect of ∼ −0.11 W m−2 at the Arctic sea ice surface (∼ 8 % of the clean background cloud effect, excluding cloud fraction changes. Aerosol presence is related to reduced precipitation, cloud thickness, and radar reflectivity, and in some cases, an increased likelihood of cloud presence in the liquid phase. These observations are inconsistent with a glaciation indirect effect and are consistent with either a deactivation effect or less-efficient secondary ice formation related to smaller liquid cloud droplets. However, this cloud subset shows large differences in surface and meteorological forcing in shallow and higher-altitude clouds and between sea ice and open-ocean regions. For example, optically thin, predominantly liquid clouds are much more likely to overlay another cloud over the open ocean, which may reduce aerosol indirect effects on the surface. Also, shallow clouds over

  7. ENSO signals on sea-surface salinity in the eastern tropical pacific ocean

    Directory of Open Access Journals (Sweden)

    1998-01-01

    Full Text Available SIGNAUX DE L’ENSO SUR LA SALINITE DE LA SURFACE DE LA MER DANS L’OCEAN PACIFIQUE TROPICAL ORIENTAL. Nous présentons les variations de la température et de la salinité de surface. Des navires de commerce ont été récemment équipés de thermosalinographes automatiques qui permettent d’échantillonner en continu et de localiser le front de salinité le long de la ligne Panama-Tahiti, séparant les masses d’eaux du golfe de Panama et celles du Pacifique central sud. La variation en latitude de la position du front halin suit la position de la zone de convergence intertropicale des vents du Pacifique. La salinité donne ainsi des informations supplémentaires sur le développement du phénomène El Niño dans le Pacifique tropical. La future transmission par satellite de la salinité de surface permettra de suivre en temps réel la distribution de la salinité de surface qui est étroitement liée aux échanges entre l’océan et l’atmosphère. SEÑALES DEL ENSO SOBRE LA SALINIDAD DE LA SUPERFICIE DEL OCÉANO PACÍFICO ORIENTAL. Presentamos las variaciones de la temperatura y de la salinidad de superficie. Barcos de comercio fueron recientemente equipados con termo-saliógrafos automáticos, los cuales permiten observar un muestreo continuo y ubicar el frente de salinidad en la recta Panamá-Tahiti, la cual separa las masas de agua del golfo de Panamá con las del Pacífico centro Sur. La variación en latitud de la ubicación del frente halino acompaña a la posición de la Zona de Convergencia Intertropical de los vientos del Pacífico. La salinidad proporciona también informaciones adicionales sobre el desarrollo del Fenómeno El Niño en el Pacífico tropical. La futura transmisión por satélite de la salinidad de superficie permitirá el monitoreo en tiempo real de la distribución en tiempo real de la salinidad de superficie, la cual está estrechamente vinculada con los intercambios entre el océano y la atmósfera. Various data

  8. Observations of Near-Surface Current Shear Help Describe Oceanic Oil and Plastic Transport

    Science.gov (United States)

    Laxague, Nathan J. M.; Ö-zgökmen, Tamay M.; Haus, Brian K.; Novelli, Guillaume; Shcherbina, Andrey; Sutherland, Peter; Guigand, Cédric M.; Lund, Björn; Mehta, Sanchit; Alday, Matias; Molemaker, Jeroen

    2018-01-01

    Plastics and spilled oil pose a critical threat to marine life and human health. As a result of wind forcing and wave motions, theoretical and laboratory studies predict very strong velocity variation with depth over the upper few centimeters of the water column, an observational blind spot in the real ocean. Here we present the first-ever ocean measurements of the current vector profile defined to within 1 cm of the free surface. In our illustrative example, the current magnitude averaged over the upper 1 cm of the ocean is shown to be nearly four times the average over the upper 10 m, even for mild forcing. Our findings indicate that this shear will rapidly separate pieces of marine debris which vary in size or buoyancy, making consideration of these dynamics essential to an improved understanding of the pathways along which marine plastics and oil are transported.

  9. Role of sea surface wind stress forcing on transport between Tropical Pacific and Indian Ocean

    Science.gov (United States)

    Zhao, Q.

    Using an Indian-Pacific Ocean Circulation Model (IPOM) a simulation study on the Transports of between Tropical Pacific and Indian Ocean such as Indonesian Through flow (ITF) has been done. IPOM covered the area 25°E-70°W, 35°S-60°N. There are 31 levels in the vertical with 22 levels upper 400m in it. The horizontal resolution is 1/3° lat x 1.5° lon between 10°S and 10°N. The coastline and ocean topography of IPOM is prepared from Scripps topography data on 1x1°grid. Forcing IPOM with monthly observational wind stress in 1990-1999 the interannual variation of sea temperature has been reproduced well, not only on El Nino in the Pacific but also on Indian Ocean Dipole (IOD). Therefore, the oceanic circulations in the tropical ocean are reasonable. The analyses of the oceanic circulations from the simulations suggest that the transport southward through Makassar Strait is the primary route of thermocline water masses from the North Pacific to the Indonesian sea. The transport westward through Bali-Western Australian Transect (BWAT, at 117.5E) can be thought as the final output of ITF through the archipelago to Indian Ocean. The transport westward through BWAT is in 8-12S above 150m, its core centered near surface 10S, which looks like a jet. The westward velocity is more than 50 cm/s. The transport shows significant seasonal and interannual variations. The maximum is in Jul-Oct, minimum in Jan-Mar. These results are consistent with some observation basically. The correlation analyses indict that the variations of transport westward is related with the southeasterly anomaly in the east tropical Indian ocean. The transport variation lags wind anomaly about 3 months. The correlation coefficient is more than 0.6. The transport is strong during IOD, for example in 1994 and 1997. The variations are also related with the northwesterly anomaly in the center equatorial Pacific and the easterly in the eastern equatorial Pacific. The transport is strong in most ENSO

  10. Importance of 3D Processes Near the Ocean's Surface for Material Transport

    Science.gov (United States)

    Ozgokmen, T. M.

    2014-12-01

    There are a number of practical problems that demand an accurate knowledge of ocean currents near the surface of the ocean. It is known that oceanic coherent features transport heat and carry out vertical exchange of biogeochemical tracers. Ocean currents can affect biological primary production, air-sea gas exchanges and global tracer budgets. Ocean currents are also important for the dispersion of substances that pose a danger to society, economy and human health. Examples of such events include algal blooms, the Fukushima nuclear plant incident in the Pacific Ocean in 2011, and repeated large oil spills in the Gulf of Mexico, namely the IXTOC in 1978 and the Deepwater Horizon event in 2010. Such incidents demand accurate answers to questions such as ``where will the pollutant go?", ``how fast will it get there?" and ``how much pollutant will arrive there?", and in some instances ``where did the pollutant come from?". The answers to these questions are critical to the allocation of limited response resources, and in determining the overall impact of the events. We will summarize the efforts by the Consortium for Advanced Research on Transport of Hydrocarbon in the Environment (CARTHE). One of the primary objectives of CARTHE is to improve predictive modeling capability for flows near the air-sea interface. In particular, two large experiments, Grand Lagrangian Deployment (GLAD) and Surf-zone and Coastal Oil Pathways Experiment (SCOPE), coordinated with real-time modeling were instructive on processes influencing near-surface material transport. Findings on submesoscale flows as well as model deficiencies to capture processes relevant to transport will be discussed. Insight into future modeling and observational plans will be provided.

  11. Single molecule force measurements delineate salt, pH and surface effects on biopolymer adhesion

    International Nuclear Information System (INIS)

    Pirzer, T; Geisler, M; Hugel, T; Scheibel, T

    2009-01-01

    In this paper we probe the influence of surface properties, pH and salt on the adhesion of recombinant spider silk proteins onto solid substrates with single molecule force spectroscopy. A single engineered spider silk protein (monomeric C 16 or dimeric (QAQ) 8 NR3) is covalently bound with one end to an AFM tip, which assures long-time measurements for hours with one and the same protein. The tip with the protein is brought into contact with various substrates at various buffer conditions and then retracted to desorb the protein. We observe a linear dependence of the adhesion force on the concentration of three selected salts (NaCl, NaH 2 PO 4 and NaI) and a Hofmeister series both for anions and cations. As expected, the more hydrophobic C 16 shows a higher adhesion force than (QAQ) 8 NR3, and the adhesion force rises with the hydrophobicity of the substrate. Unexpected is the magnitude of the dependences—we never observe a change of more than 30%, suggesting a surprisingly well-regulated balance between dispersive forces, water-structure-induced forces as well as co-solute-induced forces in biopolymer adhesion

  12. Single molecule force measurements delineate salt, pH and surface effects on biopolymer adhesion

    Science.gov (United States)

    Pirzer, T.; Geisler, M.; Scheibel, T.; Hugel, T.

    2009-06-01

    In this paper we probe the influence of surface properties, pH and salt on the adhesion of recombinant spider silk proteins onto solid substrates with single molecule force spectroscopy. A single engineered spider silk protein (monomeric C16 or dimeric (QAQ)8NR3) is covalently bound with one end to an AFM tip, which assures long-time measurements for hours with one and the same protein. The tip with the protein is brought into contact with various substrates at various buffer conditions and then retracted to desorb the protein. We observe a linear dependence of the adhesion force on the concentration of three selected salts (NaCl, NaH2PO4 and NaI) and a Hofmeister series both for anions and cations. As expected, the more hydrophobic C16 shows a higher adhesion force than (QAQ)8NR3, and the adhesion force rises with the hydrophobicity of the substrate. Unexpected is the magnitude of the dependences—we never observe a change of more than 30%, suggesting a surprisingly well-regulated balance between dispersive forces, water-structure-induced forces as well as co-solute-induced forces in biopolymer adhesion.

  13. CAROLS: A New Airborne L-Band Radiometer for Ocean Surface and Land Observations

    Directory of Open Access Journals (Sweden)

    Ernesto Lopez-Baeza

    2011-01-01

    Full Text Available The “Cooperative Airborne Radiometer for Ocean and Land Studies” (CAROLS L-Band radiometer was designed and built as a copy of the EMIRAD II radiometer constructed by the Technical University of Denmark team. It is a fully polarimetric and direct sampling correlation radiometer. It is installed on board a dedicated French ATR42 research aircraft, in conjunction with other airborne instruments (C-Band scatterometer—STORM, the GOLD-RTR GPS system, the infrared CIMEL radiometer and a visible wavelength camera. Following initial laboratory qualifications, three airborne campaigns involving 21 flights were carried out over South West France, the Valencia site and the Bay of Biscay (Atlantic Ocean in 2007, 2008 and 2009, in coordination with in situ field campaigns. In order to validate the CAROLS data, various aircraft flight patterns and maneuvers were implemented, including straight horizontal flights, circular flights, wing and nose wags over the ocean. Analysis of the first two campaigns in 2007 and 2008 leads us to improve the CAROLS radiometer regarding isolation between channels and filter bandwidth. After implementation of these improvements, results show that the instrument is conforming to specification and is a useful tool for Soil Moisture and Ocean Salinity (SMOS satellite validation as well as for specific studies on surface soil moisture or ocean salinity.

  14. Effect of ocean acidification on the benthic foraminifera

    NARCIS (Netherlands)

    Keul, N.; Langer, G.; de Nooijer, L.J.; Bijma, J.

    2013-01-01

    About 30% of the anthropogenically released CO2 is taken up by the oceans; such uptake causes surface ocean pH to decrease and is commonly referred to as ocean acidification (OA). Foraminifera are one of the most abundant groups of marine calcifiers, estimated to precipitate ca. 50 % of biogenic

  15. VOPcPhO:P3HT composite micro-structures with nano-porous surface morphology

    Energy Technology Data Exchange (ETDEWEB)

    Azmer, Mohamad Izzat [Low Dimensional Materials Research Centre (LDMRC), Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Ahmad, Zubair, E-mail: zubairtarar@qu.edu.qa [Center for Advanced Materials (CAM), Qatar University, P. O. Box 2713, Doha (Qatar); Sulaiman, Khaulah, E-mail: khaulah@um.edu.my [Low Dimensional Materials Research Centre (LDMRC), Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Touati, Farid [Department of Electrical Engineering, College of Engineering, Qatar University, P. O. Box 2713, Doha (Qatar); Bawazeer, Tahani M. [Department of Chemistry, Faculty of Applied Science, Umm Al-Qura University, Makkah (Saudi Arabia); Alsoufi, Mohammad S. [Mechanical Engineering Department, College of Engineering and Islamic Architecture, Umm Al-Qura University, Makkah (Saudi Arabia)

    2017-03-31

    Highlights: • VOPcPhO:P3HT micro-structures with nano-porous surface morphology have been formed. • Multidimensional structures have been formed by electro-spraying technique. • The electro-sprayed films are very promising for the humidity sensors. - Abstract: In this paper, composite micro-structures of Vanadyl 2,9,16,23-tetraphenoxy-29H,31H-phthalocyanine) (VOPcPhO) and Poly (3-hexylthiophene-2,5-diyl) (P3HT) complex with nano-porous surface morphology have been developed by electro-spraying technique. The structural and morphological characteristics of the VOPcPhO:P3HT composite films have been studied by field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The multidimensional VOPcPhO:P3HT micro-structures formed by electro-spraying with nano-porous surface morphology are very promising for the humidity sensors due to the pore sizes in the range of micro to nano-meters scale. The performance of the VOPcPhO:P3HT electro-sprayed sensor is superior in term of sensitivity, hysteresis and response/recovery times as compared to the spin-coated one. The electro-sprayed humidity sensor exhibits ∼3 times and 0.19 times lower hysteresis in capacitive and resistive mode, respectively, as compared to the spin-coated humidity sensor.

  16. Limitations in the use of low pH extraction to distinguish internalized from cell surface-bound radiolabeled antibody

    International Nuclear Information System (INIS)

    Ong, Gaik Lin; Mattes, M. Jules

    2000-01-01

    Internalization by cells of radiolabeled protein ligands bound to the cell surface is frequently analyzed by extraction of the cells with low pH buffers. This treatment supposedly strips the ligands from the cell surface, and remaining molecules are considered to be internalized. However, we show herein that: (1) low molecular weight catabolic products that are trapped within lysosomes (residualizing radiolabels) are efficiently extracted by low pH buffers, under the same conditions used to remove cell surface-bound material, and (2) low pH treatment lyses the majority of the cells, as shown with both a nonadherent and an adherent cell line, with the release of most of a 51 Cr label. Still, low pH extraction was effective at demonstrating Ab internalization, as has been demonstrated many times. These effects of low pH treatment may be attributed to the fixative properties of these buffers. Regardless of the mechanism, these data must be taken into consideration in interpreting the results of such experiments

  17. Northerly surface winds over the eastern North Pacific Ocean in spring and summer

    Science.gov (United States)

    Taylor, S.V.; Cayan, D.R.; Graham, N.E.; Georgakakos, K.P.

    2008-01-01

    Persistent spring and summer northerly surface winds are the defining climatological feature of the western coast of North America, especially south of the Oregon coast. Northerly surface winds are important for upwelling and a vast array of other biological, oceanic, and atmospheric processes. Intermittence in northerly coastal surface wind is characterized and wind events are quantitatively defined using coastal buoy data south of Cape Mendocino on the northern California coast. The defined wind events are then used as a basis for composites in order to explain the spatial evolution of various atmospheric and oceanic processes. Wind events involve large-scale changes in the three-dimensional atmospheric circulation including the eastern North Pacific subtropical anticyclone and southeast trade winds. Composites of QSCAT satellite scatterometer wind estimates from 1999 to 2005 based on a single coastal buoy indicate that wind events typically last 72-96 h and result in anomalies in surface wind and Ekman pumping that extend over 1000 kin from the west coast of North America. It may be useful to consider ocean circulation and dependent ecosystem dynamics and the distribution of temperature, moisture, and aerosols in the atmospheric boundary layer in the context of wind events defined herein. Copyright 2008 by the American Geophysical Union.

  18. Sea Surface Temperature and Ocean Color Variability in the South China Sea

    Science.gov (United States)

    Conaty, A. P.

    2001-12-01

    The South China Sea is a marginal sea in the Southeast Asian region whose surface circulation is driven by monsoons and whose surface currents have complex seasonal patterns. Its rich natural resources and strategic location have made its small islands areas of political dispute among the neighboring nations. This study aims to show the seasonal and interannual variability of sea surface temperature and ocean color in South China Sea. It makes use of NOAA's Advanced Very High Resolution Radiometer (AVHRR) satellite data sets on sea surface temperature for the period 1981-2000 and NASA's Nimbus-7 Coastal Zone Color Scanner (CZCS) and Sea-viewing Wide Field-of-view Sensor (SeaWiFS) satellite data sets on pigment concentration (ocean color) for the period 1981-1996 and 1997-2000, respectively. Transect lines were drawn along several potential hotspot areas to show the variability in sea surface temperature and pigment concentration through time. In-situ data on sea surface temperature along South China Sea were likewise plotted to see the variability with time. Higher seasonal variability in sea surface temperature was seen at higher latitudes. Interannual variability was within 1-3 Kelvin. In most areas, pigment concentration was higher during northern hemisphere winter and autumn, after the monsoon rains, with a maximum of 30 milligrams per cubic meter.

  19. The artificial object detection and current velocity measurement using SAR ocean surface images

    Science.gov (United States)

    Alpatov, Boris; Strotov, Valery; Ershov, Maksim; Muraviev, Vadim; Feldman, Alexander; Smirnov, Sergey

    2017-10-01

    Due to the fact that water surface covers wide areas, remote sensing is the most appropriate way of getting information about ocean environment for vessel tracking, security purposes, ecological studies and others. Processing of synthetic aperture radar (SAR) images is extensively used for control and monitoring of the ocean surface. Image data can be acquired from Earth observation satellites, such as TerraSAR-X, ERS, and COSMO-SkyMed. Thus, SAR image processing can be used to solve many problems arising in this field of research. This paper discusses some of them including ship detection, oil pollution control and ocean currents mapping. Due to complexity of the problem several specialized algorithm are necessary to develop. The oil spill detection algorithm consists of the following main steps: image preprocessing, detection of dark areas, parameter extraction and classification. The ship detection algorithm consists of the following main steps: prescreening, land masking, image segmentation combined with parameter measurement, ship orientation estimation and object discrimination. The proposed approach to ocean currents mapping is based on Doppler's law. The results of computer modeling on real SAR images are presented. Based on these results it is concluded that the proposed approaches can be used in maritime applications.

  20. Oceanic Transport of Surface Meltwater from the Southern Greenland Ice Sheet

    Science.gov (United States)

    Luo, Hao; Castelao, Renato M.; Rennermalm, Asa K.; Tedesco, Marco; Bracco, Annalisa; Yager, Patricia L.; Mote, Thomas L.

    2016-01-01

    The Greenland ice sheet has undergone accelerating mass losses during recent decades. Freshwater runoff from ice melt can influence fjord circulation and dynamic1 and the delivery of bioavailable micronutrients to the ocean. It can also have climate implications, because stratification in the adjacent Labrador Sea may influence deep convection and the strength of the Atlantic meridional overturning circulation. Yet, the fate of the meltwater in the ocean remains unclear. Here, we use a high-resolution ocean model to show that only 1-15% of the surface meltwater runoff originating from southwest Greenland is transported westwards. In contrast, up to 50-60% of the meltwater runoff originating from southeast Greenland is transported westwards into the northern Labrador Sea, leading to significant salinity and stratification anomalies far from the coast. Doubling meltwater runoff, as predicted in future climate scenarios, results in a more-than-double increase in anomalies offshore that persists further into the winter. Interannual variability in offshore export of meltwater is tightly related to variability in wind forcing. The new insight that meltwaters originating from the west and east coasts have different fates indicates that future changes in mass loss rates and surface runoff will probably impact the ocean differently, depending on their Greenland origins.

  1. Near Surface Ocean Experimental Technology Workshop Proceedings Held at Naval Ocean Research and Development Activity, NSTL Station, Mississippi on 6-8 November 1979,

    Science.gov (United States)

    1980-02-01

    have been made by Sippican Corporation of Marion, Massachusetts. An example of our use was a survey in ,June 1978 around the 2 km high Caryn Seamount ...Sound. McGraw-Hill, New York, 384 pp. 8. Wishner, K. F., 1979, The biomass and ecology of the deep-sea benthopelagic (near-bottom) zooplankton, Ph.D...COMPONENT PART NOTICE THIS PAPER IS A COMPONENT PART OF THE FOLLOWING COMPILATION REPORT: (TITLE): Near Sarface Ocean Experimental Technology Workshop

  2. Relationship between plants in Europe and surface temperatures of the Atlantic Ocean during the glacial maximum

    Energy Technology Data Exchange (ETDEWEB)

    Van Campo, M

    1984-01-01

    In Europe and North America, the deciduous forest, whether or not mixed with conifers, prevails within boundaries which coincide with the 12 and 18/sup 0/C isotherms of Ocean surface temperatures in August; within Europe this forest points to the limit of the Atlantic influence and bevels out as it is squeezed between coniferous forest to the NE (thermic boundary) and steppe to the SE (hydric boundary). During the glacial age this forest disappeared from its main European area and remained only in mountain refuges. Thus, the temperature of the eastern Atlantic surface waters, off Europe, control the nature of its vegetation. Variations in the pollen curve of pines, birches, Artemisia, Chenopodiaceae and Ephedra are accounted for by the climatic variations in southern Europe before 13,000 yr BP. It is seen that a very arid climate culminated at about 15,000 yr BP. It corresponds to the most active iceberg calving which considerably lowered the Ocean surface temperature far to the south. In spite of the increasing summer temperatures, this temperature remained as cold as it was during the glacial maximum. The result is the lowest evaporation from the Ocean hence a minimum of clouds and a minimum of rain. The end of the first phase of the deglaciation at +/- 13,000 yr BP corresponds to a warming up of the Ocean surface bringing about increased evaporation, hence rains over the continent. The evolution of the vegetation in Europe at the end of the glacial times from south of the ice sheet down to the Mediterranean, depends as much, if not more, on rains than on temperatures.

  3. Molecular layer deposition of APTES on silicon nanowire biosensors: Surface characterization, stability and pH response

    International Nuclear Information System (INIS)

    Liang, Yuchen; Huang, Jie; Zang, Pengyuan; Kim, Jiyoung; Hu, Walter

    2014-01-01

    Graphical abstract: - Abstract: We report the use of molecular layer deposition (MLD) for depositing 3-aminopropyltriethoxysilane (APTES) on a silicon dioxide surface. The APTES monolayer was characterized using spectroscopic ellipsometry, contact angle goniometry, and atomic force microscopy. Effects of reaction time of repeating pulses and simultaneous feeding of water vapor with APTES were tested. The results indicate that the synergistic effects of water vapor and reaction time are significant for the formation of a stable monolayer. Additionally, increasing the number of repeating pulses improved the APTES surface coverage but led to saturation after 10 pulses. In comparing MLD with solution-phase deposition, the APTES surface coverage and the surface quality were nearly equivalent. The hydrolytic stability of the resulting films was also studied. The results confirmed that the hydrolysis process was necessary for MLD to obtain stable surface chemistry. Furthermore, we compared the pH sensing results of Si nanowire field effect transistors (Si NWFETs) modified by both the MLD and solution methods. The highly repeatable pH sensing results reflected the stability of APTES monolayers. The results also showed an improved pH response of the sensor prepared by MLD compared to the one prepared by the solution treatment, which indicated higher surface coverage of APTES

  4. Molecular layer deposition of APTES on silicon nanowire biosensors: Surface characterization, stability and pH response

    Science.gov (United States)

    Liang, Yuchen; Huang, Jie; Zang, Pengyuan; Kim, Jiyoung; Hu, Walter

    2014-12-01

    We report the use of molecular layer deposition (MLD) for depositing 3-aminopropyltriethoxysilane (APTES) on a silicon dioxide surface. The APTES monolayer was characterized using spectroscopic ellipsometry, contact angle goniometry, and atomic force microscopy. Effects of reaction time of repeating pulses and simultaneous feeding of water vapor with APTES were tested. The results indicate that the synergistic effects of water vapor and reaction time are significant for the formation of a stable monolayer. Additionally, increasing the number of repeating pulses improved the APTES surface coverage but led to saturation after 10 pulses. In comparing MLD with solution-phase deposition, the APTES surface coverage and the surface quality were nearly equivalent. The hydrolytic stability of the resulting films was also studied. The results confirmed that the hydrolysis process was necessary for MLD to obtain stable surface chemistry. Furthermore, we compared the pH sensing results of Si nanowire field effect transistors (Si NWFETs) modified by both the MLD and solution methods. The highly repeatable pH sensing results reflected the stability of APTES monolayers. The results also showed an improved pH response of the sensor prepared by MLD compared to the one prepared by the solution treatment, which indicated higher surface coverage of APTES.

  5. KARIN: The Ka-Band Radar Interferometer for the Proposed Surface Water and Ocean Topography (SWOT) Mission

    Science.gov (United States)

    Esteban-Fernandez, Daniel; Peral, Eva; McWatters, Dalia; Pollard, Brian; Rodriguez, Ernesto; Hughes, Richard

    2013-01-01

    Over the last two decades, several nadir profiling radar altimeters have provided our first global look at the ocean basin-scale circulation and the ocean mesoscale at wavelengths longer than 100 km. Due to sampling limitations, nadir altimetry is unable to resolve the small wavelength ocean mesoscale and sub-mesoscale that are responsible for the vertical mixing of ocean heat and gases and the dissipation of kinetic energy from large to small scales. The proposed Surface Water and Ocean Topography (SWOT) mission would be a partnership between NASA, CNES (Centre National d'Etudes Spaciales) and the Canadian Space Agency, and would have as one of its main goals the measurement of ocean topography with kilometer-scale spatial resolution and centimeter scale accuracy. In this paper, we provide an overview of all ocean error sources that would contribute to the SWOT mission.

  6. Unveiling the role and life strategies of viruses from the surface to the dark ocean

    KAUST Repository

    Lara, Elena; Vaqué , Dolors; Sà , Elisabet Laia; Boras, Julia A.; Gomes, Ana; Borrull, Encarna; Dí ez-Vives, Cristina; Teira, Eva; Pernice, Massimo C.; Garcia, Francisca C.; Forn, Irene; Castillo, Yaiza M.; Peiró , Aida; Salazar, Guillem; Moran, Xose Anxelu G.; Massana, Ramon; Catalá , Teresa S.; Luna, Gian Marco; Agusti, Susana; Estrada, Marta; Gasol, Josep M M; Duarte, Carlos M.

    2017-01-01

    Viruses are a key component of marine ecosystems, but the assessment of their global role in regulating microbial communities and the flux of carbon is precluded by a paucity of data, particularly in the deep ocean. We assessed patterns in viral abundance and production and the role of viral lysis as a driver of prokaryote mortality, from surface to bathypelagic layers, across the tropical and subtropical oceans. Viral abundance showed significant differences between oceans in the epipelagic and mesopelagic, but not in the bathypelagic, and decreased with depth, with an average power-law scaling exponent of −1.03 km−1 from an average of 7.76 × 106 viruses ml−1 in the epipelagic to 0.62 × 106 viruses ml−1 in the bathypelagic layer with an average integrated (0 to 4000 m) viral stock of about 0.004 to 0.044 g C m−2, half of which is found below 775 m. Lysogenic viral production was higher than lytic viral production in surface waters, whereas the opposite was found in the bathypelagic, where prokaryotic mortality due to viruses was estimated to be 60 times higher than grazing. Free viruses had turnover times of 0.1 days in the bathypelagic, revealing that viruses in the bathypelagic are highly dynamic. On the basis of the rates of lysed prokaryotic cells, we estimated that viruses release 145 Gt C year−1 in the global tropical and subtropical oceans. The active viral processes reported here demonstrate the importance of viruses in the production of dissolved organic carbon in the dark ocean, a major pathway in carbon cycling.

  7. Unveiling the role and life strategies of viruses from the surface to the dark ocean

    KAUST Repository

    Lara, Elena

    2017-09-07

    Viruses are a key component of marine ecosystems, but the assessment of their global role in regulating microbial communities and the flux of carbon is precluded by a paucity of data, particularly in the deep ocean. We assessed patterns in viral abundance and production and the role of viral lysis as a driver of prokaryote mortality, from surface to bathypelagic layers, across the tropical and subtropical oceans. Viral abundance showed significant differences between oceans in the epipelagic and mesopelagic, but not in the bathypelagic, and decreased with depth, with an average power-law scaling exponent of −1.03 km−1 from an average of 7.76 × 106 viruses ml−1 in the epipelagic to 0.62 × 106 viruses ml−1 in the bathypelagic layer with an average integrated (0 to 4000 m) viral stock of about 0.004 to 0.044 g C m−2, half of which is found below 775 m. Lysogenic viral production was higher than lytic viral production in surface waters, whereas the opposite was found in the bathypelagic, where prokaryotic mortality due to viruses was estimated to be 60 times higher than grazing. Free viruses had turnover times of 0.1 days in the bathypelagic, revealing that viruses in the bathypelagic are highly dynamic. On the basis of the rates of lysed prokaryotic cells, we estimated that viruses release 145 Gt C year−1 in the global tropical and subtropical oceans. The active viral processes reported here demonstrate the importance of viruses in the production of dissolved organic carbon in the dark ocean, a major pathway in carbon cycling.

  8. Remote sensing of ocean surface currents: a review of what is being observed and what is being assimilated

    Science.gov (United States)

    Isern-Fontanet, Jordi; Ballabrera-Poy, Joaquim; Turiel, Antonio; García-Ladona, Emilio

    2017-10-01

    Ocean currents play a key role in Earth's climate - they impact almost any process taking place in the ocean and are of major importance for navigation and human activities at sea. Nevertheless, their observation and forecasting are still difficult. First, no observing system is able to provide direct measurements of global ocean currents on synoptic scales. Consequently, it has been necessary to use sea surface height and sea surface temperature measurements and refer to dynamical frameworks to derive the velocity field. Second, the assimilation of the velocity field into numerical models of ocean circulation is difficult mainly due to lack of data. Recent experiments that assimilate coastal-based radar data have shown that ocean currents will contribute to increasing the forecast skill of surface currents, but require application in multidata assimilation approaches to better identify the thermohaline structure of the ocean. In this paper we review the current knowledge in these fields and provide a global and systematic view of the technologies to retrieve ocean velocities in the upper ocean and the available approaches to assimilate this information into ocean models.

  9. Phylogeography and pigment type diversity of Synechococcus cyanobacteria in surface waters of the northwestern pacific ocean.

    Science.gov (United States)

    Xia, Xiaomin; Partensky, Frédéric; Garczarek, Laurence; Suzuki, Koji; Guo, Cui; Yan Cheung, Shun; Liu, Hongbin

    2017-01-01

    The widespread unicellular cyanobacteria Synechococcus are major contributors to global marine primary production. Here, we report their abundance, phylogenetic diversity (as assessed using the RNA polymerase gamma subunit gene rpoC1) and pigment diversity (as indirectly assessed using the laterally transferred cpeBA genes, encoding phycoerythrin-I) in surface waters of the northwestern Pacific Ocean, sampled over nine distinct cruises (2008-2015). Abundance of Synechococcus was low in the subarctic ocean and South China Sea, intermediate in the western subtropical Pacific Ocean, and the highest in the Japan and East China seas. Clades I and II were by far the most abundant Synechococcus lineages, the former dominating in temperate cold waters and the latter in (sub)tropical waters. Clades III and VI were also fairly abundant in warm waters, but with a narrower distribution than clade II. One type of chromatic acclimater (3dA) largely dominated the Synechococcus communities in the subarctic ocean, while another (3dB) and/or cells with a fixed high phycourobilin to phycoerythrobilin ratio (pigment type 3c) predominated at mid and low latitudes. Altogether, our results suggest that the variety of pigment content found in most Synechococcus clades considerably extends the niches that they can colonize and therefore the whole genus habitat. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  10. Chemical equilibrium modeling of organic acids, pH, aluminum, and iron in Swedish surface waters.

    Science.gov (United States)

    Sjöstedt, Carin S; Gustafsson, Jon Petter; Köhler, Stephan J

    2010-11-15

    A consistent chemical equilibrium model that calculates pH from charge balance constraints and aluminum and iron speciation in the presence of natural organic matter is presented. The model requires input data for total aluminum, iron, organic carbon, fluoride, sulfate, and charge balance ANC. The model is calibrated to pH measurements (n = 322) by adjusting the fraction of active organic matter only, which results in an error of pH prediction on average below 0.2 pH units. The small systematic discrepancy between the analytical results for the monomeric aluminum fractionation and the model results is corrected for separately for two different fractionation techniques (n = 499) and validated on a large number (n = 3419) of geographically widely spread samples all over Sweden. The resulting average error for inorganic monomeric aluminum is around 1 µM. In its present form the model is the first internally consistent modeling approach for Sweden and may now be used as a tool for environmental quality management. Soil gibbsite with a log *Ks of 8.29 at 25°C together with a pH dependent loading function that uses molar Al/C ratios describes the amount of aluminum in solution in the presence of organic matter if the pH is roughly above 6.0.

  11. Vertical eddy diffusion as a key mechanism for removing perfluorooctanoic acid (PFOA) from the global surface oceans

    NARCIS (Netherlands)

    Lohmann, R.; Jurado Cojo, E.|info:eu-repo/dai/nl/325788227; Dijkstra, H.A.|info:eu-repo/dai/nl/073504467; Dachs, J.

    2013-01-01

    Here we estimate the importance of vertical eddy diffusion in removing perfluorooctanoic acid (PFOA) from the surface Ocean and assess its importance as a global sink. Measured water column profiles of PFOA were reproduced by assuming that vertical eddy diffusion in a 3-layer ocean model is the sole

  12. Fluorine uptake into the human enamel surface from fluoride-containing sealing materials during cariogenic pH cycling

    Science.gov (United States)

    Yasuhiro, Matsuda; Katsushi, Okuyama; Hiroko, Yamamoto; Hisanori, Komatsu; Masashi, Koka; Takahiro, Sato; Naoki, Hashimoto; Saiko, Oki; Chiharu, Kawamoto; Hidehiko, Sano

    2015-04-01

    To prevent the formation of caries and reduce dentin hypersensitivity, sealing materials, either with or without fluoride, are generally applied on the tooth in clinical practice. Application of fluoride-free sealing materials results in the formation of an acid-resistant layer on the tooth surface. On the other hand, fluoride-containing sealing materials might not only form an acid-resistant layer but could possibly further provide fluoride to enhance remineralization and reduce demineralization. In this study, the demineralization prevention ability and fluorine uptake rate in human enamel of fluoride-containing sealing materials ["MS coats F" (MSF)] and fluoride-free sealing materials ("hybrid coats 2" [HI]) were evaluated using an automatic pH cycling system. Each material was applied to the original tooth surface, the cut surfaces were covered with sticky wax, and the automatic pH-cycling system simulated daily acid changes (pH 6.8-4.5) occurring in the oral cavity for 4 weeks. Caries progression was analyzed using transverse microradiography (TMR) taken pre and post the 4 weeks of pH cycling. The fluorine and calcium distributions in the carious lesion in each specimen were evaluated using the proton-induced gamma emission (PIGE) and proton-induced X-ray (PIXE) techniques, respectively. TMR analysis showed that both MSF and HI had a caries-preventing effect after 4 weeks of pH cycling. PIGE/PIXE analysis demonstrated that only MSF resulted in fluoride uptake in the enamel surface. Therefore, MSF can help to form an acid-resistant layer and provide fluoride to the enamel surface. The presence of fluoride on the enamel surface suggested that MSF could prevent demineralization, even if the acid-resistant layer was removed, in clinical settings. The data obtained using the PIGE and PIXE techniques are useful for understanding the benefits of the use of a fluoride-containing sealing material for preventing caries.

  13. Overview and preliminary results of the Surface Ocean Aerosol Production (SOAP campaign

    Directory of Open Access Journals (Sweden)

    C. S. Law

    2017-11-01

    Full Text Available Establishing the relationship between marine boundary layer (MBL aerosols and surface water biogeochemistry is required to understand aerosol and cloud production processes over the remote ocean and represent them more accurately in earth system models and global climate projections. This was addressed by the SOAP (Surface Ocean Aerosol Production campaign, which examined air–sea interaction over biologically productive frontal waters east of New Zealand. This overview details the objectives, regional context, sampling strategy and provisional findings of a pilot study, PreSOAP, in austral summer 2011 and the following SOAP voyage in late austral summer 2012. Both voyages characterized surface water and MBL composition in three phytoplankton blooms of differing species composition and biogeochemistry, with significant regional correlation observed between chlorophyll a and DMSsw. Surface seawater dimethylsulfide (DMSsw and associated air–sea DMS flux showed spatial variation during the SOAP voyage, with maxima of 25 nmol L−1 and 100 µmol m−2 d−1, respectively, recorded in a dinoflagellate bloom. Inclusion of SOAP data in a regional DMSsw compilation indicates that the current climatological mean is an underestimate for this region of the southwest Pacific. Estimation of the DMS gas transfer velocity (kDMS by independent techniques of eddy covariance and gradient flux showed good agreement, although both exhibited periodic deviations from model estimates. Flux anomalies were related to surface warming and sea surface microlayer enrichment and also reflected the heterogeneous distribution of DMSsw and the associated flux footprint. Other aerosol precursors measured included the halides and various volatile organic carbon compounds, with first measurements of the short-lived gases glyoxal and methylglyoxal in pristine Southern Ocean marine air indicating an unidentified local source. The application of a real-time clean sector

  14. Evaluation of fitting functions for the representation of an O(3P)+H2 potential energy surface. I

    International Nuclear Information System (INIS)

    Wagner, A.F.; Schatz, G.C.; Bowman, J.M.

    1981-01-01

    The DIM surface of Whitlock, Muckerman, and Fisher for the O( 3 P)+H 2 system is used as a test case to evaluate the usefulness of a variety of fitting functions for the representation of potential energy surfaces. Fitting functions based on LEPS, BEBO, and rotated Morse oscillator (RMO) forms are examined. Fitting procedures are developed for combining information about a small portion of the surface and the fitting function to predict where on the surface more information must be obtained to improve the accuracy of the fit. Both unbiased procedures and procedures heavily biased toward the saddle point region of the surface are investigated. Collinear quasiclassical trajectory calculations of the reaction rate constant and one and three dimensional transition state theory rate constant calculations are performed and compared for selected fits and the exact DIM test surface. Fitting functions based on BEBO and RMO forms are found to give quite accurate results

  15. Deep and surface circulation in the Northwest Indian Ocean from Argo, surface drifter, and in situ profiling current observations

    Science.gov (United States)

    Stryker, S. A.; Dimarco, S. F.; Stoessel, M. M.; Wang, Z.

    2010-12-01

    The northwest Indian Ocean is a region of complex circulation and atmospheric influence. The Persian (Arabian) Gulf and Red Sea contribute toward the complexity of the region. This study encompasses the surface and deep circulation in the region ranging from 0°N-35°N and 40°E-80°E from January 2002-December 2009. Emphasis is in the Persian Gulf, Oman Sea and Arabian Sea (roughly from 21°N-26°N and 56°E-63°E) using a variety of in situ and observation data sets. While there is a lot known about the Persian Gulf and Arabian Sea, little is known about the Oman Sea. Circulation in the northwest Indian Ocean is largely influenced by seasonal monsoon winds. From the winter monsoon to the summer monsoon, current direction reverses. Marginal sea inflow and outflow are also seasonally variable, which greatly impacts the physical water mass properties in the region. In situ and observation data sets include data from Argo floats (US GODAE), surface drifters (AOML) and an observation system consisting of 4 independent moorings and a cabled ocean observatory in the Oman Sea. The observing system in the Oman Sea was installed by Lighthouse R & D Enterprises, Inc. beginning in 2005, and measures current, temperature, conductivity, pressure, dissolved oxygen and turbidity, using the Aanderaa Recording Doppler Current Profiler (RDCP) 600 and the Aanderaa Recording Current Meter (RCM) 11. The cabled ocean observatory measures dissolved oxygen, temperature and salinity between 65 m and 1000 m and reports in real-time. Argo floats in the region have a parking depth range from 500 m to 2000 m. At 1000 m depth, 98% of the velocity magnitudes range from less than 1 cm/s to 20 cm/s. The Somali Current and Northeast/Southwest Monsoon Currents are present, reversing from summer to winter. At 2000 m depth, the Somali and Monsoon Currents are still present but have smaller velocities with 98% ranging from less than 1 cm/s to 13 cm/s. At both 1000 m and 2000 m, larger velocities occur

  16. Surface water carbon dioxide in the southwest Indian sector of the Southern Ocean

    International Nuclear Information System (INIS)

    Metzl, N.; Brunet, C.; Poisson, A.

    1991-01-01

    Measurements of partial pressure of carbon dioxide (pCO 2 ), total dissolved inorganic carbon (TCO 2 ), total alkalinity (TA) and chlorophyll a (Chl a) have been made in surface water in the southwestern Indian sector of the Southern Ocean (20-85 degE) in the austral summer (INDIVAT V cruise, January-February 1987). Between Antarctica and Africa, pCO 2 distribution was linked to the oceanic frontal zones and Chl a variations. The pCO 2 spatial structure was very close to that explored in summer 1967 in the same region but the pCO 2 differences between the ocean and the atmosphere were smaller in 1987 than 20 years ago. At all latitudes strongly contrasting surface pCO 2 characteristics were found between eastern (around 80 degE) and western (around 25 degE) regions; CO 2 sources were mainly in the west and CO 2 sinks in the east. South of 60 degS, the contrast could be due to biological activity. Between 60 degS and the Antarctic Polar Front, intensification of upwelling might be responsible for the higher pC) 2 values in the west.37 refs.; 4 figs

  17. High colored dissolved organic matter (CDOM) absorption in surface waters of the central-eastern Arctic Ocean: Implications for biogeochemistry and ocean color algorithms.

    Science.gov (United States)

    Gonçalves-Araujo, Rafael; Rabe, Benjamin; Peeken, Ilka; Bracher, Astrid

    2018-01-01

    As consequences of global warming sea-ice shrinking, permafrost thawing and changes in fresh water and terrestrial material export have already been reported in the Arctic environment. These processes impact light penetration and primary production. To reach a better understanding of the current status and to provide accurate forecasts Arctic biogeochemical and physical parameters need to be extensively monitored. In this sense, bio-optical properties are useful to be measured due to the applicability of optical instrumentation to autonomous platforms, including satellites. This study characterizes the non-water absorbers and their coupling to hydrographic conditions in the poorly sampled surface waters of the central and eastern Arctic Ocean. Over the entire sampled area colored dissolved organic matter (CDOM) dominates the light absorption in surface waters. The distribution of CDOM, phytoplankton and non-algal particles absorption reproduces the hydrographic variability in this region of the Arctic Ocean which suggests a subdivision into five major bio-optical provinces: Laptev Sea Shelf, Laptev Sea, Central Arctic/Transpolar Drift, Beaufort Gyre and Eurasian/Nansen Basin. Evaluating ocean color algorithms commonly applied in the Arctic Ocean shows that global and regionally tuned empirical algorithms provide poor chlorophyll-a (Chl-a) estimates. The semi-analytical algorithms Generalized Inherent Optical Property model (GIOP) and Garver-Siegel-Maritorena (GSM), on the other hand, provide robust estimates of Chl-a and absorption of colored matter. Applying GSM with modifications proposed for the western Arctic Ocean produced reliable information on the absorption by colored matter, and specifically by CDOM. These findings highlight that only semi-analytical ocean color algorithms are able to identify with low uncertainty the distribution of the different optical water constituents in these high CDOM absorbing waters. In addition, a clustering of the Arctic Ocean

  18. The effect of aluminium nanocoating and water pH value on the wettability behavior of an aluminium surface

    Science.gov (United States)

    Ali, Naser; Teixeira, Joao A.; Addali, Abdulmajid; Al-Zubi, Feras; Shaban, Ehab; Behbehani, Ismail

    2018-06-01

    Experimental investigation was performed to highlight the influence of ionic bounding and surface roughness effects on the surface wettability. Nanocoating technique via e-beam physical vapor deposition process was used to fabricate aluminium (Al) film of 50, 100, and 150 nm on the surface of an Al substrate. Microstructures of the samples before and after deposition were observed using an atomic force microscopy. A goniometer device was later on used to examine the influence of surface topography on deionised water of pH 4, 7 and 9 droplets at a temperature ranging from 10 °C to 60 °C through their contact angles with the substrate surface, for both coated and uncoated samples. It was found that, although the coated layer has reduced the mean surface roughness of the sample from 10.7 nm to 4.23 nm, by filling part of the microstructure gaps with Al nanoparticles, the wettability is believed to be effected by the ionic bounds between the surface and the free anions in the fluid. As the deionised water of pH 4, and 9 gave an increase in the average contact angles with the increase of the coated layer thickness. On the other hand, the deionised water of pH 7 has showed a negative relation with the film thickness, where the contact angle reduced as the thickness of the coated layer was increased. The results from the aforementioned approach had showed that nanocoating can endorse the hydrophobicity (unwitting) nature of the surface when associated with free ions hosted by the liquid.

  19. How do Greenhouse Gases Warm the Ocean? Investigation of the Response of the Ocean Thermal Skin Layer to Air-Sea Surface Heat Fluxes.

    Science.gov (United States)

    Wong, E.; Minnett, P. J.

    2016-12-01

    There is much evidence that the ocean is heating due to an increase in concentrations of greenhouse gases (GHG) in the atmosphere from human activities. GHGs absorbs infrared (IR) radiation and re-emits the radiation back to the ocean's surface which is subsequently absorbed resulting in a rise in the ocean heat content. However, the incoming longwave radiation, LWin, is absorbed within the top micrometers of the ocean's surface, where the thermal skin layer (TSL) exists and does not directly heat the upper few meters of the ocean. We are therefore motivated to investigate the physical mechanism between the absorption of IR radiation and its effect on heat transfer at the air-sea boundary. The hypothesis is that since heat lost through the air-sea interface is controlled by the TSL, which is directly influenced by the absorption and emission of IR radiation, the heat flow through the TSL adjusts to maintain the surface heat loss, and thus modulates the upper ocean heat content. This hypothesis is investigated through utilizing clouds to represent an increase in LWin and analyzing retrieved TSL vertical profiles from a shipboard IR spectrometer from two research cruises. The data is limited to night-time, no precipitation and low winds of heat from the absorption of the cloud infrared irradiance back into the atmosphere through processes such as evaporation. Instead, we observe the surplus energy, from absorbing increasing levels of LWin, adjusts the curvature of the TSL such that there is a lower gradient at the interface between the TSL and the mixed layer. The release of heat stored within the mixed layer is therefore hindered while the additional energy within the TSL is cycled back into the atmosphere. This results in heat beneath the TSL, which is a product of the absorption of solar radiation during the day, to be retained and cause an increase in upper ocean heat content.

  20. Arctic surface temperatures from Metop AVHRR compared to in situ ocean and land data

    Directory of Open Access Journals (Sweden)

    G. Dybkjær

    2012-11-01

    Full Text Available The ice surface temperature (IST is an important boundary condition for both atmospheric and ocean and sea ice models and for coupled systems. An operational ice surface temperature product using satellite Metop AVHRR infra-red data was developed for MyOcean. The IST can be mapped in clear sky regions using a split window algorithm specially tuned for sea ice. Clear sky conditions prevail during spring in the Arctic, while persistent cloud cover limits data coverage during summer. The cloud covered regions are detected using the EUMETSAT cloud mask. The Metop IST compares to 2 m temperature at the Greenland ice cap Summit within STD error of 3.14 °C and to Arctic drifting buoy temperature data within STD error of 3.69 °C. A case study reveals that the in situ radiometer data versus satellite IST STD error can be much lower (0.73 °C and that the different in situ measurements complicate the validation. Differences and variability between Metop IST and in situ data are analysed and discussed. An inter-comparison of Metop IST, numerical weather prediction temperatures and in situ observation indicates large biases between the different quantities. Because of the scarcity of conventional surface temperature or surface air temperature data in the Arctic, the satellite IST data with its relatively good coverage can potentially add valuable information to model analysis for the Arctic atmosphere.

  1. Biofilm three-dimensional architecture influences in situ pH distribution pattern on the human enamel surface.

    Science.gov (United States)

    Xiao, Jin; Hara, Anderson T; Kim, Dongyeop; Zero, Domenick T; Koo, Hyun; Hwang, Geelsu

    2017-06-01

    To investigate how the biofilm three-dimensional (3D) architecture influences in situ pH distribution patterns on the enamel surface. Biofilms were formed on human tooth enamel in the presence of 1% sucrose or 0.5% glucose plus 0.5% fructose. At specific time points, biofilms were exposed to a neutral pH buffer to mimic the buffering of saliva and subsequently pulsed with 1% glucose to induce re-acidification. Simultaneous 3D pH mapping and architecture of intact biofilms was performed using two-photon confocal microscopy. The enamel surface and mineral content characteristics were examined successively via optical profilometry and microradiography analyses. Sucrose-mediated biofilm formation created spatial heterogeneities manifested by complex networks of bacterial clusters (microcolonies). Acidic regions (pHinterior of microcolonies, which impedes rapid neutralization (taking more than 120 min for neutralization). Glucose exposure rapidly re-created the acidic niches, indicating formation of diffusion barriers associated with microcolonies structure. Enamel demineralization (white spots), rougher surface, deeper lesion and more mineral loss appeared to be associated with the localization of these bacterial clusters at the biofilm-enamel interface. Similar 3D architecture was observed in plaque-biofilms formed in vivo in the presence of sucrose. The formation of complex 3D architectures creates spatially heterogeneous acidic microenvironments in close proximity of enamel surface, which might correlate with the localized pattern of the onset of carious lesions (white spot like) on teeth.

  2. Response surface optimization of pH and ionic strength for emulsion characteristics of egg yolk.

    Science.gov (United States)

    Kurt, S; Zorba, O

    2009-11-01

    Effects of pH (3.5, 4.5, 6.0, 7.5, and 8.5) and ionic strength (0.05, 0.15, 0.30, 0.45, and 0.55 M NaCl) on emulsion capacity, emulsion stability (ES), apparent yield stress of emulsion (AYS), and emulsion density (ED) of egg yolk were studied by using a model system. Ionic strength and pH had significant (P emulsion characteristics of egg yolk. Their interaction effects also have been found significant on ES, AYS, and ED. Predicted solutions of ES, emulsion capacity, and ED were minimum. The critical point of ES was determined to be at pH 6.08 and an ionic strength of 0.49 (M NaCl). Predicted solution for AYS was a maximum, which was determined to be at pH 6.04 and an ionic strength of 0.29 (M NaCl). Optimum values of pH and ionic strenght were 4.61 to 7.43 and 0.10 to 0.47, respectively.

  3. An updated climatology of surface dimethlysulfide concentrations and emission fluxes in the global ocean

    Science.gov (United States)

    Lana, A.; Bell, T. G.; Simó, R.; Vallina, S. M.; Ballabrera-Poy, J.; Kettle, A. J.; Dachs, J.; Bopp, L.; Saltzman, E. S.; Stefels, J.; Johnson, J. E.; Liss, P. S.

    2011-03-01

    The potentially significant role of the biogenic trace gas dimethylsulfide (DMS) in determining the Earth's radiation budget makes it necessary to accurately reproduce seawater DMS distribution and quantify its global flux across the sea/air interface. Following a threefold increase of data (from 15,000 to over 47,000) in the global surface ocean DMS database over the last decade, new global monthly climatologies of surface ocean DMS concentration and sea-to-air emission flux are presented as updates of those constructed 10 years ago. Interpolation/extrapolation techniques were applied to project the discrete concentration data onto a first guess field based on Longhurst's biogeographic provinces. Further objective analysis allowed us to obtain the final monthly maps. The new climatology projects DMS concentrations typically in the range of 1-7 nM, with higher levels occurring in the high latitudes, and with a general trend toward increasing concentration in summer. The increased size and distribution of the observations in the DMS database have produced in the new climatology substantially lower DMS concentrations in the polar latitudes and generally higher DMS concentrations in regions that were severely undersampled 10 years ago, such as the southern Indian Ocean. Using the new DMS concentration climatology in conjunction with state-of-the-art parameterizations for the sea/air gas transfer velocity and climatological wind fields, we estimate that 28.1 (17.6-34.4) Tg of sulfur are transferred from the oceans into the atmosphere annually in the form of DMS. This represents a global emission increase of 17% with respect to the equivalent calculation using the previous climatology. This new DMS climatology represents a valuable tool for atmospheric chemistry, climate, and Earth System models.

  4. Long-term dynamics of chlorophyll concentration in the ocean surface layer (by space data)

    Science.gov (United States)

    Shevyrnogov, A.; Vysotskaya, G.

    To preserve the biosphere and to use it efficiently, it is necessary to gain a deep insight into the dynamics of the primary production process on our planet. Variability of chlorophyll concentration in the ocean is one of the most important components of this process. These investigations are, however, very labor-consuming, because of the difficulties related to the accessibility of the water surface and its large size. In this work long-term changes in chlorophyll concentration in the surface layer of the ocean have been analyzed on the basis of the CZCS data for 7.5 years from 1979 to 1986 and the SeaWiFS data from 1997 to 2004. It has been shown that the average chlorophyll concentration calculated in all investigated areas varies moderately. However, when analyzing spatially local trends, the areas have been detected that have significant rise and fall of chlorophyll concentrations. Some interesting features of the long-term dynamics of chlorophyll concentration have been found. The opposite directions of long-term trends (essential increase or decrease) cannot be explained only by large-scale hydrological phenomena in the ocean (currents, upwellings, etc.). The measured chlorophyll concentration results from the balance between production and destruction processes. Which process dominates is determined by various hydrophysical, hydrobiological, and climatic processes, leading to sharp rises or falls of the concentration. It is important to estimate the scale of the areas in which this or that process dominates. Therefore, the study addresses not only the dynamics of the mean value but also the dynamics of the areas in which the dominance of certain factors has led to a sharp fall or rise in chlorophyll concentration. Thus, the obtained results can be used to estimate long-term changes in the ocean biota.

  5. Biotic and surface catalyzed reactivity of nitrates at alkaline pH

    International Nuclear Information System (INIS)

    Rafrafi, Y.; Erable, B.; Ranaivomanana, H.; Bertron, A.; Albrecht, A.

    2015-01-01

    This study investigates the reactivity of nitrates in abiotic and biotic conditions at alkaline pH in the context of a repository for long-lived intermediate- level radioactive wastes. The work, carried out under environmental conditions closed to those prevailing in the storage: alkaline pH, no oxygen, solid materials (cement paste, steel), aims to identify the by-products of the nitrate reduction, to evaluate reaction kinetics and to determine the role of organic matter in these reactions with and without the presence of denitrifying microbial activity. This paper demonstrated that in the extreme conditions of pH in nuclear waste storage cells, nitrate reduction is a really possible scenario in the presence of microorganisms. (authors)

  6. Sea surface temperature (SST) and surface current data collected from the Mar Mostro during the around-the-world Volvo Ocean Race (VOR) from 2011-11-05 to 2012-07-12 (NCEI Accession 0130694)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Navigation, surface current, sea surface temperature, wind, and atmospheric pressure data collected by the Mar Mostro during the around-the-world Volvo Ocean Race...

  7. Manipulating and Monitoring On-Surface Biological Reactions by Light-Triggered Local pH Alterations.

    Science.gov (United States)

    Peretz-Soroka, Hagit; Pevzner, Alexander; Davidi, Guy; Naddaka, Vladimir; Kwiat, Moria; Huppert, Dan; Patolsky, Fernando

    2015-07-08

    Significant research efforts have been dedicated to the integration of biological species with electronic elements to yield smart bioelectronic devices. The integration of DNA, proteins, and whole living cells and tissues with electronic devices has been developed into numerous intriguing applications. In particular, the quantitative detection of biological species and monitoring of biological processes are both critical to numerous areas of medical and life sciences. Nevertheless, most current approaches merely focus on the "monitoring" of chemical processes taking place on the sensing surfaces, and little efforts have been invested in the conception of sensitive devices that can simultaneously "control" and "monitor" chemical and biological reactions by the application of on-surface reversible stimuli. Here, we demonstrate the light-controlled fine modulation of surface pH by the use of photoactive molecularly modified nanomaterials. Through the use of nanowire-based FET devices, we showed the capability of modulating the on-surface pH, by intensity-controlled light stimulus. This allowed us simultaneously and locally to control and monitor pH-sensitive biological reactions on the nanodevices surfaces, such as the local activation and inhibition of proteolytic enzymatic processes, as well as dissociation of antigen-antibody binding interactions. The demonstrated capability of locally modulating the on-surface effective pH, by a light stimuli, may be further applied in the local control of on-surface DNA hybridization/dehybridization processes, activation or inhibition of living cells processes, local switching of cellular function, local photoactivation of neuronal networks with single cell resolution and so forth.

  8. Possibilities of new materials surface sensibility express determination based on ZnSe-CdS system by pH isoelectric state measurements of the surface state

    Science.gov (United States)

    Kirovskaya, I. A.; Mironova, E. V.; Ushakov, O. V.; Nor, P. E.; Yureva, A. V.; Matyash, Yu I.

    2018-01-01

    A method for determining the hydrogen index of the surfaces isoelectric state (pHiso) at various gases pressures -possible components of the surrounding and technological media has been developed. With its use, changes in pH of binary and more complex semiconductors-components of the new system-ZnSe-CdS under the influence of nitrogen dioxide-have been found. The limiting sensitivity of surfaces - minimum PNO2, causing a change in pH has been estimated. The most active components of ZnSe-CdS system, recommended as materials for measuring cells of NO2, have been revealed. The relationship between the changing patterns with the composition of surface (acid-base) and bulk (in particular, theoretical calculated crystal density) properties has been established, allowing to find the most effective materials for sensor technology and for semiconductor analysis.

  9. Evaluating Surface Radiation Fluxes Observed From Satellites in the Southeastern Pacific Ocean

    Science.gov (United States)

    Pinker, R. T.; Zhang, B.; Weller, R. A.; Chen, W.

    2018-03-01

    This study is focused on evaluation of current satellite and reanalysis estimates of surface radiative fluxes in a climatically important region. It uses unique observations from the STRATUS Ocean Reference Station buoy in a region of persistent marine stratus clouds 1,500 km off northern Chile during 2000-2012. The study shows that current satellite estimates are in better agreement with buoy observations than model outputs at a daily time scale and that satellite data depict well the observed annual cycle in both shortwave and longwave surface radiative fluxes. Also, buoy and satellite estimates do not show any significant trend over the period of overlap or any interannual variability. This verifies the stability and reliability of the satellite data and should make them useful to examine El Niño-Southern Oscillation variability influences on surface radiative fluxes at the STRATUS site for longer periods for which satellite record is available.

  10. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2007-01-02 to 2007-12-20 (NCEI Accession 0148773)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0148773 includes Surface underway data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans (> 60...

  11. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2011-12-30 to 2012-12-23 (NCEI Accession 0148774)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0148774 includes Surface underway data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans (> 60...

  12. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2007-12-31 to 2008-10-27 (NCEI Accession 0148763)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0148763 includes Surface underway data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans (> 60...

  13. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2011-01-02 to 2011-12-18 (NCEI Accession 0148767)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0148767 includes Surface underway data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans (> 60...

  14. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2006-01-01 to 2006-12-27 (NCEI Accession 0144535)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144535 includes Surface underway data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans (> 60...

  15. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2014-12-30 to 2015-07-01 (NCEI Accession 0144343)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144343 includes Surface underway data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans (> 60...

  16. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2011-01-02 to 2011-12-19 (NCEI Accession 0144354)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144354 includes Surface underway data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans (> 60...

  17. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2007-12-30 to 2008-10-28 (NCEI Accession 0144348)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144348 includes Surface underway data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans (> 60...

  18. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2007-01-02 to 2007-12-22 (NCEI Accession 0144528)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144528 includes Surface underway data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans (> 60...

  19. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2002-03-07 to 2002-12-23 (NCEI Accession 0144356)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144356 includes Surface underway data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans (> 60...

  20. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2011-12-30 to 2012-12-24 (NCEI Accession 0144349)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144349 includes Surface underway data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans (> 60...

  1. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2013-12-31 to 2014-12-20 (NCEI Accession 0144532)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144532 includes Surface underway data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans (> 60...

  2. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2006-01-02 to 2006-12-26 (NCEI Accession 0148764)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0148764 includes Surface underway data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans (> 60...

  3. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2002-12-29 to 2003-11-30 (NCEI Accession 0144351)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144351 includes Surface underway data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans (> 60...

  4. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2012-12-31 to 2013-11-15 (NCEI Accession 0144529)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144529 includes Surface underway data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans (> 60...

  5. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2002-03-23 to 2002-12-23 (NCEI Accession 0148766)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0148766 includes Surface underway data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans (> 60...

  6. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2014-01-01 to 2014-12-20 (NCEI Accession 0145200)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0145200 includes Surface underway data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans (> 60...

  7. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2003-01-01 to 2003-12-29 (NCEI Accession 0148770)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0148770 includes Surface underway data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans (> 60...

  8. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2010-01-01 to 2011-12-19 (NCEI Accession 0148765)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0148765 includes Surface underway data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans (> 60...

  9. Sea surface salinity variability during the Indian Ocean Dipole and ENSO events in the tropical Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Grunseich, G.; Subrahmanyam, B.; Murty, V.S.N.; Giese, B.S.

    into the southwestern tropical Indian Ocean. The impact of concomitant La Niña with negative IOD is also large with an intense freshening in the southeastern Arabian Sea and salting off the northern Sumatra coast....

  10. Temperature, Salinity, Oxygen, Phosphate, pH and Alkalinity data collected in the North Atlantic Ocean, Baltic Sea, Barents Sea, Greenland Sea, North Sea, Norwegian Sea and White Sea from R/Vs Artemovsk, Atlantida, Okeanograf, Professor Rudovits, and ice observations, 1957 - 1995 (NODC Accession 0073674)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, Salinity, Oxygen, Phosphate, pH and Alkalinity data collected in the North Atlantic Ocean, Baltic Sea, Barents Sea, Greenland Sea, North Sea, Norwegian...

  11. Roughness and pH changes of enamel surface induced by soft drinks in vitro-applications of stylus profilometry, focus variation 3D scanning microscopy and micro pH sensor.

    Science.gov (United States)

    Fujii, Mie; Kitasako, Yuichi; Sadr, Alireza; Tagami, Junji

    2011-01-01

    This study aimed to evaluate enamel surface roughness (Ra) and pH before and after erosion by soft drinks. Enamel was exposed to a soft drink (cola, orange juice or green tea) for 1, 5 or 60 min; Ra was measured using contact-stylus surface profilometry (SSP) and non-contact focus variation 3D microscope (FVM). Surface pH was measured using a micro pH sensor. Data were analyzed at significance level of alpha=0.05. There was a significant correlation in Ra between SSP and FVM. FVM images showed no changes in the surface morphology after various periods of exposure to green tea. Unlike cola and orange juice, exposure to green tea did not significantly affect Ra or pH. A significant correlation was observed between surface pH and Ra change after exposure to the drinks. Optical surface analysis and micro pH sensor may be useful tools for non-damaging, quantitative assessment of soft drinks erosion on enamel.

  12. Adsorption of dyes by ACs prepared from waste tyre reinforcing fibre. Effect of texture, surface chemistry and pH.

    Science.gov (United States)

    Acevedo, Beatriz; Rocha, Raquel P; Pereira, Manuel F R; Figueiredo, José L; Barriocanal, Carmen

    2015-12-01

    This paper compares the importance of the texture and surface chemistry of waste tyre activated carbons in the adsorption of commercial dyes. The adsorption of two commercial dyes, Basic Astrazon Yellow 7GLL and Reactive Rifafix Red 3BN on activated carbons made up of reinforcing fibres from tyre waste and low-rank bituminous coal was studied. The surface chemistry of activated carbons was modified by means of HCl-HNO3 treatment in order to increase the number of functional groups. Moreover, the influence of the pH on the process was also studied, this factor being of great importance due to the amphoteric characteristics of activated carbons. The activated carbons made with reinforcing fibre and coal had the highest SBET, but the reinforcing fibre activated carbon samples had the highest mesopore volume. The texture of the activated carbons was not modified upon acid oxidation treatment, unlike their surface chemistry which underwent considerable modification. The activated carbons made with a mixture of reinforcing fibre and coal experienced the largest degree of oxidation, and so had more acid surface groups. The adsorption of reactive dye was governed by the mesoporous volume, whilst surface chemistry played only a secondary role. However, the surface chemistry of the activated carbons and dispersive interactions played a key role in the adsorption of the basic dye. The adsorption of the reactive dye was more favored in a solution of pH 2, whereas the basic dye was adsorbed more easily in a solution of pH 12. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Understanding the formation and evolution of rain-formed fresh lenses at the ocean surface

    Science.gov (United States)

    Drushka, Kyla; Asher, William E.; Ward, Brian; Walesby, Kieran

    2016-04-01

    Rain falling on the ocean produces a layer of buoyant fresher surface water, or "fresh lens." Fresh lenses can have significant impacts on satellite-in situ salinity comparisons and on exchanges between the surface and the bulk mixed layer. However, because these are small, transient features, relatively few observations of fresh lenses have been made. Here the Generalized Ocean Turbulence Model (GOTM) is used to explore the response of the upper few meters of the ocean to rain events. Comparisons with observations from several platforms demonstrate that GOTM can reproduce the main characteristics of rain-formed fresh lenses. Idealized sensitivity tests show that the near-surface vertical salinity gradient within fresh lenses has a linear dependence on rain rate and an inverse dependence on wind speed. Yearlong simulations forced with satellite rainfall and reanalysis atmospheric parameters demonstrate that the mean salinity difference between 0.01 and 5 m, equivalent to the measurement depths of satellite radiometers and Argo floats, is -0.04 psu when averaged over the 20°S-20°N tropical band. However, when averaged regionally, the mean vertical salinity difference exceeds -0.15 psu in the Indo-Pacific warm pool, in the Pacific and Atlantic intertropical convergence zone, and in the South Pacific convergence zone. In most of these regions, salinities measured by the Aquarius satellite instrument have a fresh bias relative to Argo measurements at 5 m depth. These results demonstrate that the fresh bias in Aquarius salinities in rainy, low-wind regions may be caused by the presence of rain-produced fresh lenses.

  14. Dependence of the cyanobacterium Prochlorococcus on hydrogen peroxide scavenging microbes for growth at the ocean's surface.

    Directory of Open Access Journals (Sweden)

    J Jeffrey Morris

    2011-02-01

    Full Text Available The phytoplankton community in the oligotrophic open ocean is numerically dominated by the cyanobacterium Prochlorococcus, accounting for approximately half of all photosynthesis. In the illuminated euphotic zone where Prochlorococcus grows, reactive oxygen species are continuously generated via photochemical reactions with dissolved organic matter. However, Prochlorococcus genomes lack catalase and additional protective mechanisms common in other aerobes, and this genus is highly susceptible to oxidative damage from hydrogen peroxide (HOOH. In this study we showed that the extant microbial community plays a vital, previously unrecognized role in cross-protecting Prochlorococcus from oxidative damage in the surface mixed layer of the oligotrophic ocean. Microbes are the primary HOOH sink in marine systems, and in the absence of the microbial community, surface waters in the Atlantic and Pacific Ocean accumulated HOOH to concentrations that were lethal for Prochlorococcus cultures. In laboratory experiments with the marine heterotroph Alteromonas sp., serving as a proxy for the natural community of HOOH-degrading microbes, bacterial depletion of HOOH from the extracellular milieu prevented oxidative damage to the cell envelope and photosystems of co-cultured Prochlorococcus, and facilitated the growth of Prochlorococcus at ecologically-relevant cell concentrations. Curiously, the more recently evolved lineages of Prochlorococcus that exploit the surface mixed layer niche were also the most sensitive to HOOH. The genomic streamlining of these evolved lineages during adaptation to the high-light exposed upper euphotic zone thus appears to be coincident with an acquired dependency on the extant HOOH-consuming community. These results underscore the importance of (indirect biotic interactions in establishing niche boundaries, and highlight the impacts that community-level responses to stress may have in the ecological and evolutionary outcomes for co

  15. Antagonistic Effects of Ocean Acidification and Rising Sea Surface Temperature on the Dissolution of Coral Reef Carbonate Sediments

    Directory of Open Access Journals (Sweden)

    Daniel Trnovsky

    2016-11-01

    Full Text Available Increasing atmospheric CO2 is raising sea surface temperature (SST and increasing seawater CO2 concentrations, resulting in a lower oceanic pH (ocean acidification; OA, which is expected to reduce the accretion of coral reef ecosystems. Although sediments comprise most of the calcium carbonate (CaCO3 within coral reefs, no in situ studies have looked at the combined effects of increased SST and OA on the dissolution of coral reef CaCO3 sediments. In situ benthic chamber incubations were used to measure dissolution rates in permeable CaCO3 sands under future OA and SST scenarios in a coral reef lagoon on Australia’s Great Barrier Reef (Heron Island. End of century (2100 simulations (temperature +2.7°C and pH -0.3 shifted carbonate sediments from net precipitating to net dissolving. Warming increased the rate of benthic respiration (R by 29% per 1°C and lowered the ratio of productivity to respiration (P/R; ΔP/R = -0.23, which increased the rate of CaCO3 sediment dissolution (average net increase of 18.9 mmol CaCO3 m-2 d-1 for business as usual scenarios. This is most likely due to the influence of warming on benthic P/R which, in turn, was an important control on sediment dissolution through the respiratory production of CO2. The effect of increasing CO2 on CaCO3 sediment dissolution (average net increase of 6.5 mmol CaCO3 m-2 d-1 for business as usual scenarios was significantly less than the effect of warming. However, the combined effect of increasing both SST and pCO2 on CaCO3 sediment dissolution was non-additive (average net increase of 5.6 mmol CaCO3 m-2 d-1 due to the different responses of the benthic community. This study highlights that benthic biogeochemical processes such as metabolism and associated CaCO3 sediment dissolution respond rapidly to changes in SST and OA, and that the response to multiple environmental changes are not necessarily additive.

  16. Annual and interannual variability of scatterometer ocean surface wind over the South China Sea

    DEFF Research Database (Denmark)

    Zhang, GS; Xu, Q.; Gong, Z.

    2014-01-01

    To investigate the annual and interannual variability of ocean surface wind over the South China Sea (SCS), the vector empirical orthogonal function (VEOF) method and the Hilbert-Huang transform (HHT) method were employed to analyze a set of combined satellite scatterometer wind data during.......3% of the total variance and represents the East Asian monsoon features. The second mode of VEOF corresponds to a spring-autumn oscillation which accounts for 8.3% of the total variance. To analyze the interannual variability, the annual signal was removed from the wind data set and the VEOFs of the residuals...

  17. Modeling Surface Water Transport in the Central Pacific Ocean With 129I Records From Coral Skeletons

    Science.gov (United States)

    Beck, W.; Biddulph, D. L.; Russell, J. L.; Burr, G. S.; Jull, T. J.; Correge, T.; Roeder, B.

    2008-12-01

    129I occurs naturally in extremely low abundance via cosmic ray interactions in the atmosphere as well as by spontaneous fission of uranium. Oceanic concentrations of 129I have risen by several orders of magnitude during the last half century largely from environmental pollution coming from several point-source nuclear fuel reprocessing plants. In the Pacific basin, much of the increase has apparently come from the Hanford Nuclear reprocessing plant in the United States, with iodine primarily arriving via the Columbia River. Coral skeletons preserve records of 129I concentration of the surface waters from which they were deposited, yielding records with annual resolution or better. We will present three such records from different locations in the Pacific Ocean: the Solomon Islands, Easter Island and Clipperton Atoll. For this study, drill cores from living massive coral skeletons of the species Porites Lobata were collected from these sites. 129I/127I values were measured using accelerator mass spectrometry (AMS) at the University of Arizona with an NEC 3 MV Pelletron accelerator. Results from the analysis of the corals will be compared to the distribution of other mixed-layer tracers (chloro-fluorocarbons and tritium) collected during the World Ocean Circulation Experiment cruises conducted between 1990 and 2002. The 129I/127I records observed in these corals will also be compared to tracer transit time calculations determined from a 20th century simulation of the GFDL coupled-climate passive-tracer model.

  18. Coralline algal barium as indicator for 20th century northwestern North Atlantic surface ocean freshwater variability.

    Science.gov (United States)

    Hetzinger, S; Halfar, J; Zack, T; Mecking, J V; Kunz, B E; Jacob, D E; Adey, W H

    2013-01-01

    During the past decades climate and freshwater dynamics in the northwestern North Atlantic have undergone major changes. Large-scale freshening episodes, related to polar freshwater pulses, have had a strong influence on ocean variability in this climatically important region. However, little is known about variability before 1950, mainly due to the lack of long-term high-resolution marine proxy archives. Here we present the first multidecadal-length records of annually resolved Ba/Ca variations from Northwest Atlantic coralline algae. We observe positive relationships between algal Ba/Ca ratios from two Newfoundland sites and salinity observations back to 1950. Both records capture episodical multi-year freshening events during the 20th century. Variability in algal Ba/Ca is sensitive to freshwater-induced changes in upper ocean stratification, which affect the transport of cold, Ba-enriched deep waters onto the shelf (highly stratified equals less Ba/Ca). Algal Ba/Ca ratios therefore may serve as a new resource for reconstructing past surface ocean freshwater changes.

  19. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the North Pacific Ocean, South Atlantic Ocean and others from 2004-12-30 to 2005-11-20 (NCEI Accession 0148772)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0148772 includes Surface underway data collected from LAURENCE M. GOULD in the North Pacific Ocean, South Atlantic Ocean, South Pacific Ocean and...

  20. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the North Pacific Ocean, South Atlantic Ocean and others from 2008-12-31 to 2009-12-22 (NCEI Accession 0144533)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144533 includes Surface underway data collected from LAURENCE M. GOULD in the North Pacific Ocean, South Atlantic Ocean, South Pacific Ocean and...

  1. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the North Pacific Ocean, South Atlantic Ocean and others from 2004-12-31 to 2005-12-26 (NCEI Accession 0144531)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144531 includes Surface underway data collected from LAURENCE M. GOULD in the North Pacific Ocean, South Atlantic Ocean, South Pacific Ocean and...

  2. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from LAURENCE M. GOULD in the North Pacific Ocean, South Atlantic Ocean and others from 2008-12-31 to 2009-12-21 (NCEI Accession 0148771)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0148771 includes Surface underway data collected from LAURENCE M. GOULD in the North Pacific Ocean, South Atlantic Ocean, South Pacific Ocean and...

  3. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Barometric pressure sensor, Carbon dioxide (CO2) gas analyzer and other instruments from ROGER REVELLE in the Indian Ocean, South Pacific Ocean and others from 2007-02-04 to 2007-03-16 (NCEI Accession 0144252)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144252 includes Surface underway data collected from ROGER REVELLE in the Indian Ocean, South Pacific Ocean, Southern Oceans (> 60 degrees South)...

  4. The Response of the Ocean Thermal Skin Layer to Air-Sea Surface Heat Fluxes

    Science.gov (United States)

    Wong, Elizabeth Wing-See

    There is much evidence that the ocean is heating as a result of an increase in concentrations of greenhouse gases (GHGs) in the atmosphere from human activities. GHGs absorb infrared radiation and re-emit infrared radiation back to the ocean's surface which is subsequently absorbed. However, the incoming infrared radiation is absorbed within the top micrometers of the ocean's surface which is where the thermal skin layer exists. Thus the incident infrared radiation does not directly heat the upper few meters of the ocean. We are therefore motivated to investigate the physical mechanism between the absorption of infrared radiation and its effect on heat transfer at the air-sea boundary. The hypothesis is that since heat lost through the air-sea interface is controlled by the thermal skin layer, which is directly influenced by the absorption and emission of infrared radiation, the heat flow through the thermal skin layer adjusts to maintain the surface heat loss, assuming the surface heat loss does not vary, and thus modulates the upper ocean heat content. This hypothesis is investigated through utilizing clouds to represent an increase in incoming longwave radiation and analyzing retrieved thermal skin layer vertical temperature profiles from a shipboard infrared spectrometer from two research cruises. The data are limited to night-time, no precipitation and low winds of less than 2 m/s to remove effects of solar radiation, wind-driven shear and possibilities of thermal skin layer disruption. The results show independence of the turbulent fluxes and emitted radiation on the incident radiative fluxes which rules out the immediate release of heat from the absorption of the cloud infrared irradiance back into the atmosphere through processes such as evaporation and increase infrared emission. Furthermore, independence was confirmed between the incoming and outgoing radiative flux which implies the heat sink for upward flowing heat at the air-sea interface is more

  5. DNA immobilization on polymer-modified Si surface by controlling pH

    International Nuclear Information System (INIS)

    Demirel, Goekcen Birlik; Caykara, Tuncer

    2009-01-01

    A novel approach based on polymer-modified Si surface as DNA sensor platforms is presented. The polymer-modified Si surface was prepared by using 3-(methacryloxypropyl)trimethoxysilane [γ-MPS] and poly(acrylamide) [PAAm]. Firstly, a layer of γ-MPS was formed on the hydroxylated silicon surface as a monolayer and then modified with different molecular weight of PAAm to form polymer-modified surface. The polymer-modified Si surface was used for dsDNA immobilization. All steps about formation of layer structure were characterized by ellipsometry, atomic force microscopy (AFM), attenuated total reflectance Fourier transformed infrared (ATR-FTIR), and contact angle (CA) measurements. We found that in this case the amount of dsDNA immobilized onto the surface was dictated by the electrostatic interaction between the substrate surface and the DNA. Our results thus demonstrated that DNA molecules could be immobilized differently onto the polymer-modified support surface via electrostatic interactions.

  6. Surface signature of Mediterranean water eddies in the Northeastern Atlantic: effect of the upper ocean stratification

    Directory of Open Access Journals (Sweden)

    I. Bashmachnikov

    2012-11-01

    Full Text Available Meddies, intra-thermocline eddies of Mediterranean water, can often be detected at the sea surface as positive sea-level anomalies. Here we study the surface signature of several meddies tracked with RAFOS floats and AVISO altimetry.

    While pushing its way through the water column, a meddy raises isopycnals above. As a consequence of potential vorticity conservation, negative relative vorticity is generated in the upper layer. During the initial period of meddy acceleration after meddy formation or after a stagnation stage, a cyclonic signal is also generated at the sea-surface, but mostly the anticyclonic surface signal follows the meddy.

    Based on geostrophy and potential vorticity balance, we present theoretical estimates of the intensity of the surface signature. It appears to be proportional to the meddy core radius and to the Coriolis parameter, and inversely proportional to the core depth and buoyancy frequency. This indicates that surface signature of a meddy may be strongly reduced by the upper ocean stratification. Using climatic distribution of the stratification intensity, we claim that the southernmost limit for detection in altimetry of small meddies (with radii on the order of 10–15 km should lie in the subtropics (35–45° N, while large meddies (with radii of 25–30 km could be detected as far south as the northern tropics (25–35° N. Those results agree with observations.

  7. Modeling of the integrity of machining surfaces: application to the case of 15-5 PH stainless steel finish turning

    International Nuclear Information System (INIS)

    Mondelin, A.

    2012-01-01

    During machining, extreme conditions of pressure, temperature and strain appear in the cutting zone. In this thermo-mechanical context, the link between the cutting conditions (cutting speed, lubrication, feed rate, wear, tool coating...) and the machining surface integrity represents a major scientific target. This PhD study is a part of a global project called MIFSU (Modeling of the Integrity and Fatigue resistance of Machining Surfaces) and it focuses on the finish turning of the 15-5PH (a martensitic stainless steel used for parts of helicopter rotor). Firstly, material behavior has been studied in order to provide data for machining simulations. Stress-free dilatometry tests were conducted to obtain the austenitization kinetics of 15-5PH steel for high heating rates (up to 11,000 degrees C/s). Then, parameters of Leblond metallurgical model have been calibrated. In addition, dynamic compression tests (de/dt ranging from 0.01 to 80/s and e ≥ 1) have been performed to calibrate a strain-rate dependent elasto-plasticity model (for high strains). These tests also helped to highlight the dynamic recrystallization phenomena and their influence on the flow stress of the material. Thus, recrystallization model has also been implemented.In parallel, a numerical model for the prediction of machined surface integrity has been constructed. This model is based on a methodology called 'hybrid' (developed during the PhD thesis of Frederic Valiorgue for the AISI 304L steel). The method consists in replacing tool and chip modeling by equivalent loadings (obtained experimentally). A calibration step of these loadings has been carried out using orthogonal cutting and friction tests (with sensitivity studies of machining forces, friction and heat partition coefficients to cutting parameters variations).Finally, numerical simulations predictions of microstructural changes (austenitization and dynamic recrystallization) and residual stresses have been successfully compared with

  8. Investigating the role of wind in generating surface currents over the slope area of the Laptev Sea, Arctic Ocean

    Science.gov (United States)

    Patteson, R. N.

    2017-12-01

    Mixing mechanisms of the Arctic Ocean have profound impacts on sea ice, global ocean dynamics, and arctic communities. This project used a two-year long time series of ocean current velocities collected from eight moorings located on the Eurasian basin, as well as ERA-interim wind data, to compare and assess relationships between current and wind velocities at different depths. Determining the strength of these correlations will further scientific understanding of the degree to which wind influences mixing, with implications for heat flux, diffusion, and sea ice changes. Using statistical analysis, I calculated whether a significant relationship between wind velocity and ocean currents existed beginning at the surface level ( 50m) .The final correlation values, ranging from R = 0.11 to R = 0.28, indicated a weak relationship between wind velocity and ocean currents at the surface for all eight mooring sites. The results for the surface depth imply that correlation likely decreases with increasing depths, and thus further testing of deeper depth levels was unnecessary. This finding suggests that there is another dominant factor at play in the ocean; we postulate that topography exerts a significant influence on subsurface mixing. This study highlights the need for further research of the different mechanisms and their importance in influencing the dynamic structure of the ocean.

  9. AND logic-like pH- and light-dual controlled drug delivery by surface modified mesoporous silica nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Junwei; He, Zhaoshuai; Li, Biao; Cheng, Tanyu, E-mail: tycheng@shnu.edu.cn; Liu, Guohua

    2017-04-01

    Recently, the controlled drug delivery system has become a potential platform for biomedical application. Herein, we developed a pH and light-dual controlled cargo release system exhibiting AND logic based on MCM-41 mesoporous silica nanoparticles, which was surface modified using β-cyclodextrin (β-CD) with imine bond and azobenzene derivative. The complex of β-CD and azobenzene derivative effectively blocked the cargo delivery in pH = 7.0 phosphate buffered saline (PBS) solution without 365 nm UV light irradiation. The cargo was fully released when both factors of acidic environment (pH = 5.0 PBS) and 365 nm UV light irradiation were satisfied, meanwhile only very little cargo was delivered if one factor was satisfied. The result also demonstrates that the opening/closing of the gate and the release of the cargo in small portions can be controlled. - Highlights: • A pH and light-dual controlled cargo release system exhibiting AND logic is developed. • The delivery system can release the cargo in small potions by controlling the opening/closing of the gate. • The delivery system realizes the controlled release in zebrafish.

  10. Optimization of free radical scavenging capacity and pH of Hylocereus polyrhizus peel by Response Surface Methodology

    Science.gov (United States)

    Putranto, A. W.; Dewi, S. R.; Puspitasari, Y.; Nuriah, F. A.

    2018-03-01

    Red dragon fruit (Hylocereus polyrhizus) peel, a by-product of juice processing, contains a high antioxidant that can be used for nutraceuticals. Hence, it is important to extract and investigate its antioxidant stability. The aim of this study was to optimize the free radical scavenging capacity and pH of H. polyrhizus peel extract using Central Composite Design (CCD) under Response Surface Methodology (RSM). The extraction of H. polyrhizus peel was done by using green-Pulsed Electric Field (PEF)-assisted extraction method. Factors optimized were electric field strength (kV/cm) and extraction time (seconds). The result showed that the correlation between responses (free radical-scavenging capacity and pH) and two factors was quadratic model. The optimum conditions was obtained at the electric field strength of 3.96 kV/cm, and treatment time of 31.9 seconds. Under these conditions, the actual free radical-scavenging capacity and pH were 75.86 ± 0.2 % and 4.8, respectively. The verification model showed that the actual values are in accordance with the predicted values, and have error rate values of free radical-scavenging capacity and pH responses were 0.1% and 3.98%, respectively. We suggest to extract the H. polyrhizus peel using a green and non-thermal extraction technology, PEF-assisted extraction, for research, food applications and nutraceuticals industry.

  11. Effect of concentration and pH on the surface-enhanced Raman scattering of captopril on nano-colloidal silver surface

    Science.gov (United States)

    Gao, Junxiang; Gu, Huaimin; Liu, Fangfang; Dong, Xiao; Xie, Min; Hu, Yongjun

    2011-07-01

    In this report, Raman and surface-enhanced Raman scattering (SERS) spectra of captopril are studied in detail. Herein, the Raman bands are assigned by the density functional theory (DFT) calculations and potential energy distributions (PED) based on internal coordinates of the molecule, which are found to be in good agree with the experimental values. Furthermore, the concentration and pH dependence of the SERS intensity of the molecule is discussed. By analyzing the intensities variation of SERS bands of the different concentrations of captopril solution, it can be concluded that the molecules orientation adsorbed on the silver nanoparticles surface change with the change of the concentrations. The variation of SERS spectra of captopril with the change of pH suggests that the interaction among the adsorbates with Ag cluster depend on the protonated state of the adsorbate and the aggregation of silver nanoparticles.

  12. Seasonal dynamics of surface chlorophyll concentration and sea surface temperature, as indicator of hydrological structure of the ocean (by satellite data)

    Science.gov (United States)

    Shevyrnogov, Anatoly; Vysotskaya, Galina

    Continuous monitoring of phytopigment concentrations and sea surface temperature in the ocean by space-borne methods makes possible to estimate ecological condition of biocenoses in critical areas. Unlike land vegetation, hydrological processes largely determine phytoplank-ton dynamics, which may be either recurrent or random. The types of chlorophyll concentration dynamics and sea surface temperature can manifest as zones quasistationary by seasonal dynamics, quasistationary areas (QSA). In the papers of the authors (A. Shevyrnogov, G. Vysotskaya, E. Shevyrnogov, A study of the stationary and the anomalous in the ocean surface chlorophyll distribution by satellite data. International Journal of Remote Sensing, Vol. 25, No.7-8, pp. 1383-1387, April 2004 & A. P. Shevyrnogov, G. S. Vysotskaya, J. I. Gitelson, Quasistationary areas of chlorophyll concentra-tion in the world ocean as observed satellite data Advances in Space Research, Volume 18, Issue 7, Pages 129-132, 1996) existence of zones, which are quasi-stationary with similar seasonal dynamics of chlorophyll concentration at surface layer of ocean, was shown. Results were obtained on the base of processing of time series of satellite images SeaWiFS. It was shown that fronts and frontal zones coincide with dividing lines between quasi-stationary are-as, especially in areas of large oceanic streams. To study the dynamics of the ocean for the period from 1985 through 2012 we used data on the temperature of the surface layer of the ocean and chlorophyll concentration (AVHRR, SeaWiFS and MODIS). Biota of surface oceanic layer is more stable in comparison with quickly changing surface tem-perature. It gives a possibility to circumvent influence of high-frequency component (for exam-ple, a diurnal cycle) in investigation of dynamics of spatial distribution of surface streams. In addition, an analyses of nonstable ocean productivity phenomena, stood out time series of satellite images, showed existence of areas with

  13. Effect of surface wave propagation in a four-layered oceanic crust model

    Science.gov (United States)

    Paul, Pasupati; Kundu, Santimoy; Mandal, Dinbandhu

    2017-12-01

    Dispersion of Rayleigh type surface wave propagation has been discussed in four-layered oceanic crust. It includes a sandy layer over a crystalline elastic half-space and over it there are two more layers—on the top inhomogeneous liquid layer and under it a liquid-saturated porous layer. Frequency equation is obtained in the form of determinant. The effects of the width of different layers as well as the inhomogeneity of liquid layer, sandiness of sandy layer on surface waves are depicted and shown graphically by considering all possible case of the particular model. Some special cases have been deduced, few special cases give the dispersion equation of Scholte wave and Stoneley wave, some of which have already been discussed elsewhere.

  14. Regime-Dependent Differences in Surface Freshwater Exchange Estimates Over the Ocean

    Science.gov (United States)

    Wong, Sun; Behrangi, Ali

    2018-01-01

    Differences in gridded precipitation (P), surface evaporation (E), and the resultant surface freshwater exchange (P - E) among different products over the ocean are diagnosed as functions of moisture advection (Qadvt) and moisture tendency by dynamical convergence (Qcnvg). Compared to the GPCP product, the TRMM3B42 product captures higher frequency of precipitation with larger extreme precipitation rates in regimes of deep convection and more light rain detections in regimes of frequent occurrence of boundary layer clouds. Discrepancies in E depend on moisture flux divergence, with the OAFlux product having the largest E in regimes of divergence. Discrepancies in mean P - E in deep convective regimes are highly influenced by differences in precipitation, with the TRMM3B42 product yielding P - E histograms closer to those inferred from the reanalysis moisture flux convergence. In nonconvergent regimes, observation-based P - E histograms skew toward positive values while the inferred reanalysis histograms are symmetric about the means.

  15. Modeled Oceanic Response and Sea Surface Cooling to Typhoon Kai-Tak

    Directory of Open Access Journals (Sweden)

    Yu-Heng Tseng

    2010-01-01

    Full Text Available An ocean response to typhoon Kai-Tak is simulated using an accurate fourth-order, basin-scale ocean model. The surface winds of typhoon Kai-Tak were obtained from QuikSCAT satellite images blended with the ECMWF wind fields. An intense nonlinear mesoscale eddy is generated in the northeast South China Sea (SCS with a Rossby number of O(1 and on a 50 - 100 km horizontal scale. Inertial oscillation is clearly observed. Advection dominates as a strong wind shear drives the mixed layer flows outward, away from the typhoon center, thus forcing upwelling from deep levels with a high upwelling velocity (> 30 m day-1. A drop in sea surface temperature (SST of more than 9°C is found in both observation and simulation. We attribute this significant SST drop to the influence of the slow moving typhoon, initial stratification and bathymetry-induced upwelling in the northeast of the SCS where the typhoon hovered.

  16. Lagrangian modelling of ocean surface waves and synthetic aperture radar wave measurements

    Energy Technology Data Exchange (ETDEWEB)

    Fouques, Sebastien

    2005-07-01

    The present thesis is concerned with the estimation of the ocean wave spectrum from synthetic aperture radar imaging and the modelling of ocean surface waves using the Lagrangian formalism. The first part gives a short overview of the theories of ocean surface waves and synthetic aperture radar (SAR) whereas the second part consists of five independent publications. The first two articles investigate the influence of the radar backscatter model on the SAR imaging of ocean waves. In Article I, Monte Carlo simulations of SAR images of the ocean surface are carried out using a nonlinear backscatter model that include both specular reflection and Bragg scattering and the results are compared to simulations from the classical Hasselmann integral transform (Hasselmann and Hasselmann, 1991). It is shown that nonlinearities in the backscatter model strongly influence the imaging of range-travelling waves and that the former can suppress the range-splitting effect (Bruning et al., 1988). Furthermore, in Article II a database of Envisat-ASAR Wave Mode products co-located with directional wave spectra from the numerical model WAM and which contains range-travelling wave cases only, is set up. The WAM spectra are used as input to several ocean-to-SAR integral transforms, with various real aperture radar (RAR) models and the obtained SAR image cross-spectra are compared to the Envisat-ASAR observations. A first result is that the use of a linear backscatter model leads to a high proportion of non-physical negative backscatter values in the RAR image, as suggested by Schulz-Stellenfleth (2001). Then, a comparison between the observed SAR cross-spectra and the ones simulated through Hasselmann's integral transform reveals that only twenty percents of the observations show a range-splitting effect as strong as in the simulations. A much better agreement is obtained when using the integral transform by Schulz-Stellenfleth (2003), which is based on a nonlinear hackscatter model

  17. Variable but persistent coexistence of Prochlorococcus ecotypes along temperature gradients in the ocean's surface mixed layer.

    Science.gov (United States)

    Chandler, Jeremy W; Lin, Yajuan; Gainer, P Jackson; Post, Anton F; Johnson, Zackary I; Zinser, Erik R

    2016-04-01

    The vast majority of the phytoplankton communities in surface mixed layer of the oligotrophic ocean are numerically dominated by one of two ecotypes of Prochlorococcus, eMIT9312 or eMED4. In this study, we surveyed large latitudinal transects in the Atlantic and Pacific Ocean to determine if these ecotypes discretely partition the surface mixed layer niche, or if populations exist as a continuum along key environmental gradients, particularly temperature. Transitions of dominance occurred at approximately 19-21°C, with the eMED4 ecotype dominating the colder, and eMIT9312 ecotype dominating the warmer regions. Within these zones of regional dominance, however, the minority ecotype was not competed to extinction. Rather, a robust log-linear relationship between ecotype ratio and temperature characterized this stabilized coexistence: for every 2.5°C increase in temperature, the eMIT9312:eMED4 ratio increased by an order of magnitude. This relationship was observed in both quantitative polymerase chain reaction and in pyrosequencing assays. Water column stratification also contributed to the ecotype ratio along the basin-scale transects, but to a lesser extent. Finally, instances where the ratio of the eMED4 and eMIT9312 abundances did not correlate well with temperature were identified. Such occurrences are likely due to changes in water temperatures outpacing changes in community structure. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  18. Methotrexate loading in chitosan nanoparticles at a novel pH: Response surface modeling, optimization and characterization.

    Science.gov (United States)

    Hashad, Rania A; Ishak, Rania A H; Geneidi, Ahmed S; Mansour, Samar

    2016-10-01

    The aim of this study was to assess the feasibility of employing a novel but critical formulation pH (6.2) to encapsulate an anionic model drug (methotrexate, MTX) into chitosan(Cs)-tripolyphosphate nanoparticles(NPs). A response surface methodology using a three-level full factorial design was applied studying the effects of two independent variables namely; Cs concentration and MTX concentration. The responses investigated were the entrapment efficiency (EE%), mean hydrodynamic particle size (PS), polydispersity index (PDI) and zeta potential (ZP). In order to simultaneously optimize the series of models obtained, the desirability function approach was applied with a goal to produce high percent of MTX encapsulated into highly charged Cs-TPP NPs of homogenous optimum PS. MTX-loaded CsNPs were successfully prepared at the novel pH applied. The suggested significant models were found quadratic for EE, PS and ZP responses, while 2-factor interaction model for PDI. The optimization overlay graph showed that the maximum global desirability, D=0.856, was reached when the conditions were set at high Cs and MTX concentration. Thus, the use of such optimized conditions, at this novel pH, achieved a maximum drug EE% (73.38%) into NPs characterized by optimum PS (232.6nm), small PDI value (0.195) and highly surface charged (+18.4mV). Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Fluorine uptake into the human enamel surface from fluoride-containing sealing materials during cariogenic pH cycling

    Energy Technology Data Exchange (ETDEWEB)

    Yasuhiro, Matsuda, E-mail: matsuda@den.hokudai.ac.jp [Department of Restorative Dentistry, Graduate School of Dental Medicine Hokkaido University (Japan); Katsushi, Okuyama [Department of Restorative Dentistry, Graduate School of Dental Medicine Hokkaido University (Japan); Hiroko, Yamamoto [Graduate School of Dentistry, Osaka University (Japan); Hisanori, Komatsu [Department of Restorative Dentistry, Graduate School of Dental Medicine Hokkaido University (Japan); Masashi, Koka; Takahiro, Sato [Takasaki Advanced Radiation Research Institute, JAEA (Japan); Naoki, Hashimoto; Saiko, Oki; Chiharu, Kawamoto; Hidehiko, Sano [Department of Restorative Dentistry, Graduate School of Dental Medicine Hokkaido University (Japan)

    2015-04-01

    To prevent the formation of caries and reduce dentin hypersensitivity, sealing materials, either with or without fluoride, are generally applied on the tooth in clinical practice. Application of fluoride-free sealing materials results in the formation of an acid-resistant layer on the tooth surface. On the other hand, fluoride-containing sealing materials might not only form an acid-resistant layer but could possibly further provide fluoride to enhance remineralization and reduce demineralization. In this study, the demineralization prevention ability and fluorine uptake rate in human enamel of fluoride-containing sealing materials [“MS coats F” (MSF)] and fluoride-free sealing materials (“hybrid coats 2” [HI]) were evaluated using an automatic pH cycling system. Each material was applied to the original tooth surface, the cut surfaces were covered with sticky wax, and the automatic pH-cycling system simulated daily acid changes (pH 6.8–4.5) occurring in the oral cavity for 4 weeks. Caries progression was analyzed using transverse microradiography (TMR) taken pre and post the 4 weeks of pH cycling. The fluorine and calcium distributions in the carious lesion in each specimen were evaluated using the proton-induced gamma emission (PIGE) and proton-induced X-ray (PIXE) techniques, respectively. TMR analysis showed that both MSF and HI had a caries-preventing effect after 4 weeks of pH cycling. PIGE/PIXE analysis demonstrated that only MSF resulted in fluoride uptake in the enamel surface. Therefore, MSF can help to form an acid-resistant layer and provide fluoride to the enamel surface. The presence of fluoride on the enamel surface suggested that MSF could prevent demineralization, even if the acid-resistant layer was removed, in clinical settings. The data obtained using the PIGE and PIXE techniques are useful for understanding the benefits of the use of a fluoride-containing sealing material for preventing caries.

  20. Fluorine uptake into the human enamel surface from fluoride-containing sealing materials during cariogenic pH cycling

    International Nuclear Information System (INIS)

    Yasuhiro, Matsuda; Katsushi, Okuyama; Hiroko, Yamamoto; Hisanori, Komatsu; Masashi, Koka; Takahiro, Sato; Naoki, Hashimoto; Saiko, Oki; Chiharu, Kawamoto; Hidehiko, Sano

    2015-01-01

    To prevent the formation of caries and reduce dentin hypersensitivity, sealing materials, either with or without fluoride, are generally applied on the tooth in clinical practice. Application of fluoride-free sealing materials results in the formation of an acid-resistant layer on the tooth surface. On the other hand, fluoride-containing sealing materials might not only form an acid-resistant layer but could possibly further provide fluoride to enhance remineralization and reduce demineralization. In this study, the demineralization prevention ability and fluorine uptake rate in human enamel of fluoride-containing sealing materials [“MS coats F” (MSF)] and fluoride-free sealing materials (“hybrid coats 2” [HI]) were evaluated using an automatic pH cycling system. Each material was applied to the original tooth surface, the cut surfaces were covered with sticky wax, and the automatic pH-cycling system simulated daily acid changes (pH 6.8–4.5) occurring in the oral cavity for 4 weeks. Caries progression was analyzed using transverse microradiography (TMR) taken pre and post the 4 weeks of pH cycling. The fluorine and calcium distributions in the carious lesion in each specimen were evaluated using the proton-induced gamma emission (PIGE) and proton-induced X-ray (PIXE) techniques, respectively. TMR analysis showed that both MSF and HI had a caries-preventing effect after 4 weeks of pH cycling. PIGE/PIXE analysis demonstrated that only MSF resulted in fluoride uptake in the enamel surface. Therefore, MSF can help to form an acid-resistant layer and provide fluoride to the enamel surface. The presence of fluoride on the enamel surface suggested that MSF could prevent demineralization, even if the acid-resistant layer was removed, in clinical settings. The data obtained using the PIGE and PIXE techniques are useful for understanding the benefits of the use of a fluoride-containing sealing material for preventing caries

  1. Chemistry of Frozen NaCl and MgSO4 Brines - Implications for Surface Expression of Europa's Ocean Composition

    Science.gov (United States)

    Johnson, P. V.; Hodyss, R. P.; Choukroun, M.; Vu, T. H.

    2015-12-01

    The composition of Europa's subsurface ocean is a critical determinant of its habitability, but current analysis of the ocean composition is limited to its expression on the Europan surface. While there is observational evidence indicating that ocean materials make their way to the surface, our understanding of the chemical processes that can alter this material under Europan surface conditions is limited. We present experimental data on the chemistry of mixed solutions of NaCl and MgSO4 as they are frozen to 100 K, replicating the conditions that may occur when subsurface ocean fluids are emplaced onto Europa's surface. Confocal micro-Raman spectroscopy is used to study the formation of salts during the freezing process, and the interaction of ions in the frozen brines. Our data indicate that mixed aqueous solutions of NaCl and MgSO4 form Na2SO4 and MgCl2 preferentially when frozen, rather than making NaCl and MgSO4 precipitates. The detection of epsomite (MgSO4Ÿ•7H2O) on Europa's surface may therefore imply an ocean composition relatively low in sodium, unless radiolytic chemistry converts MgCl2 to MgSO4 as suggested by Hand and Brown 2013 (ApJ 145 110). These results have important implications for the interpretation of remote sensing data of Europa's surface.

  2. Reconstructing surface ocean circulation with 129I time series records from corals.

    Science.gov (United States)

    Chang, Ching-Chih; Burr, George S; Jull, A J Timothy; Russell, Joellen L; Biddulph, Dana; White, Lara; Prouty, Nancy G; Chen, Yue-Gau; Shen, Chuan-Chou; Zhou, Weijian; Lam, Doan Dinh

    2016-12-01

    The long-lived radionuclide 129 I (half-life: 15.7 × 10 6  yr) is well-known as a useful environmental tracer. At present, the global 129 I in surface water is about 1-2 orders of magnitude higher than pre-1960 levels. Since the 1990s, anthropogenic 129 I produced from industrial nuclear fuels reprocessing plants has been the primary source of 129 I in marine surface waters of the Atlantic and around the globe. Here we present four coral 129 I time series records from: 1) Con Dao and 2) Xisha Islands, the South China Sea, 3) Rabaul, Papua New Guinea and 4) Guam. The Con Dao coral 129 I record features a sudden increase in 129 I in 1959. The Xisha coral shows similar peak values for 129 I as the Con Dao coral, punctuated by distinct low values, likely due to the upwelling in the central South China Sea. The Rabaul coral features much more gradual 129 I increases in the 1970s, similar to a published record from the Solomon Islands. The Guam coral 129 I record contains the largest measured values for any site, with two large peaks, in 1955 and 1959. Nuclear weapons testing was the primary 129 I source in the Western Pacific in the latter part of the 20th Century, notably from testing in the Marshall Islands. The Guam 1955 peak and Con Dao 1959 increases are likely from the 1954 Castle Bravo test, and the Operation Hardtack I test is the most likely source of the 1959 peak observed at Guam. Radiogenic iodine found in coral was carried primarily through surface ocean currents. The coral 129 I time series data provide a broad picture of the surface distribution and depth penetration of 129 I in the Pacific Ocean over the past 60 years. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Ocean acidification and calcium carbonate saturation states in the coastal zone of the West Antarctic Peninsula

    NARCIS (Netherlands)

    Jones, E.M.; Fenton, M.; Meredith, M.P.; Clargo, N.M.; Ossebaar, S.; Ducklow, H.W.; Venables, H.J.; De Baar, H.J.W.

    2017-01-01

    The polar oceans are particularly vulnerable to ocean acidification; the lowering of seawater pH and carbonate mineral saturation states due to uptake of atmospheric carbon dioxide (CO2). High spatial variability in surface water pH and saturation states (Ω) for two biologically-important calcium

  4. Ocean acidification and calcium carbonate saturation states in the coastal zone of the West Antarctic Peninsula

    NARCIS (Netherlands)

    Jones, Elizabeth M.; Fenton, Mairi; Meredith, Michael P.; Clargo, Nicola M.; Ossebaar, Sharyn; Ducklow, Hugh W.; Venables, Hugh J.; de Baar, Henricus

    The polar oceans are particularly vulnerable to ocean acidification; the lowering of seawater pH and carbonate mineral saturation states due to uptake of atmospheric carbon dioxide (CO2). High spatial variability in surface water pH and saturation states (Omega) for two biologically-important

  5. Ocean Surface Topography Mission (OSTM) /Jason-3: Near Real-Time Altimetry Validation System (NRTAVS) QA Reports, 2015 - (NCEI Accession 0122600)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Jason-3 is the fourth mission in U.S.-European series of satellite missions that measure the height of the ocean surface. Scheduled to launch in 2015, the mission...

  6. The Sentinel-3 Surface Topography Mission (S-3 STM): Level 2 SAR Ocean Retracker

    Science.gov (United States)

    Dinardo, S.; Lucas, B.; Benveniste, J.

    2015-12-01

    The SRAL Radar Altimeter, on board of the ESA Mission Sentinel-3 (S-3), has the capacity to operate either in the Pulse-Limited Mode (also known as LRM) or in the novel Synthetic Aperture Radar (SAR) mode. Thanks to the initial results from SAR Altimetry obtained exploiting CryoSat-2 data, lately the interest by the scientific community in this new technology has significantly increased and consequently the definition of accurate processing methodologies (along with validation strategies) has now assumed a capital importance. In this paper, we present the algorithm proposed to retrieve from S-3 STM SAR return waveforms the standard ocean geophysical parameters (ocean topography, wave height and sigma nought) and the validation results that have been so far achieved exploiting the CryoSat-2 data as well as the simulated data. The inversion method (retracking) to extract from the return waveform the geophysical information is a curve best-fitting scheme based on the bounded Levenberg-Marquardt Least-Squares Estimation Method (LEVMAR-LSE). The S-3 STM SAR Ocean retracking algorithm adopts, as return waveform’s model, the “SAMOSA” model [Ray et al, 2014], named after the R&D project SAMOSA (led by Satoc and funded by ESA), in which it has been initially developed. The SAMOSA model is a physically-based model that offers a complete description of a SAR Altimeter return waveform from ocean surface, expressed in the form of maps of reflected power in Delay-Doppler space (also known as stack) or expressed as multilooked echoes. SAMOSA is able to account for an elliptical antenna pattern, mispointing errors in roll and yaw, surface scattering pattern, non-linear ocean wave statistics and spherical Earth surface effects. In spite of its truly comprehensive character, the SAMOSA model comes with a compact analytical formulation expressed in term of Modified Bessel functions. The specifications of the retracking algorithm have been gathered in a technical document (DPM

  7. 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

  8. An atlast of XBT thermal structures and TOPEX/POSEIDON sea surface heights in the north Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Gopalakrishna, V.V.; Ali, M.M.; Araligidad, N.; Shenoi, S.S.C.; Shum, C.K.; Yi, Y.

    the Indian XBT Program were used to plot the sub-surface thermal structures of the Indian Ocean for 1993 to 2003. Since these in situ measurements are just along the ship tracks, sea surface height observations from the TOPEX altimeter were also plotted over...

  9. Analysis of the global ocean sampling (GOS) project for trends in iron uptake by surface ocean microbes.

    Science.gov (United States)

    Toulza, Eve; Tagliabue, Alessandro; Blain, Stéphane; Piganeau, Gwenael

    2012-01-01

    Microbial metagenomes are DNA samples of the most abundant, and therefore most successful organisms at the sampling time and location for a given cell size range. The study of microbial communities via their DNA content has revolutionized our understanding of microbial ecology and evolution. Iron availability is a critical resource that limits microbial communities' growth in many oceanic areas. Here, we built a database of 2319 sequences, corresponding to 140 gene families of iron metabolism with a large phylogenetic spread, to explore the microbial strategies of iron acquisition in the ocean's bacterial community. We estimate iron metabolism strategies from metagenome gene content and investigate whether their prevalence varies with dissolved iron concentrations obtained from a biogeochemical model. We show significant quantitative and qualitative variations in iron metabolism pathways, with a higher proportion of iron metabolism genes in low iron environments. We found a striking difference between coastal and open ocean sites regarding Fe(2+) versus Fe(3+) uptake gene prevalence. We also show that non-specific siderophore uptake increases in low iron open ocean environments, suggesting bacteria may acquire iron from natural siderophore-like organic complexes. Despite the lack of knowledge of iron uptake mechanisms in most marine microorganisms, our approach provides insights into how the iron metabolic pathways of microbial communities may vary with seawater iron concentrations.

  10. Inter-annual variability of sea surface temperature, wind speed and sea surface height anomaly over the tropical Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Muraleedharan, P.M.; Pankajakshan, T.; Sathe, P.V.

    Being land-locked at the north, the Indian Ocean and its surrounding atmosphere behave in such a way that the ocean-atmosphere interaction over this domain is different from that over the other oceans, exhibiting a peculiar dynamics. The sparse data...

  11. Exopolymer Particles in the Sea Surface Microlayer (SML) of the Coastal Pacific Ocean

    Science.gov (United States)

    Thornton, D. C.; Brooks, S. D.; Chen, J.

    2015-12-01

    Exchanges of matter and energy between the ocean and atmosphere occur through the sea surface microlayer (SML). The SML is biogeochemically distinct from the underlying water and overlying atmosphere in terms of physical environment, chemical composition, and biological community. We sampled the Pacific Ocean in coastal waters off the state of Oregon (United States) along a seaward transect out from the mouth of the Columbia River (3 stations) and in deeper waters beyond the shelf break (2 stations) in July 2011. SML samples were collected using the glass plate method and the underlying water was sampled using a peristaltic pump from 1, 5 and 10 m depth. The samples were analyzed for carbohydrates and exopolymer particles. Carbohydrates were significantly enriched in the SML compared with the underlying water. The concentration of polysaccharides was higher than monosaccharides at all depths. We enumerated two classes of exopolymer particles: transparent exopolymer particles (TEP) and Coomassie staining particles (CSP). TEP are composed of acid polysaccharides and CSP are formed from proteins. While TEP have been widely studied, CSP are generally overlooked, despite the biogeochemical significance of proteins. Our data showed that TEP and CSP concentrations were enriched in the SML compared with the underlying waters in most cases. The ubiquitous presence of empty diatom frustules in the samples indicates that the collapse of a diatom bloom was the source of the exopolymers. Further, we conducted image analysis of particle size and abundance, which indicated that TEP and CSP are not the same particles and form distinct populations in the ocean. Our data confirm recent observations indicating that TEP are an important component of the SML. In addition, these data show that CSP are also important components of the SML.

  12. Ikaite crystals in melting sea ice – implications for pCO2 and pH levels in Arctic surface waters

    DEFF Research Database (Denmark)

    Rysgaard, Søren; Glud, R.N.; Lennert, K.

    2012-01-01

    A major issue of Arctic marine science is to understand whether the Arctic Ocean is, or will be, a source or sink for air-sea CO 2 exchange. This has been complicated by the recent discoveries of ikaite (a polymorph of CaCO 3•6H 2O) in Arctic and Antarctic sea ice, which indicate that multiple...... chemical transformations occur in sea ice with a possible effect on CO 2 and pH conditions in surface waters. Here, we report on biogeochemical conditions, microscopic examinations and x-ray diffraction analysis of single crystals from a melting 1.7 km 2 (0.5-1 m thick) drifting ice floe in the Fram Strait...... during summer. Our findings show that ikaite crystals are present throughout the sea ice but with larger crystals appearing in the upper ice layers. Ikaite crystals placed at elevated temperatures disintegrated into smaller crystallites and dissolved. During our field campaign in late June, melt reduced...

  13. Gradient flux measurements of sea-air DMS transfer during the Surface Ocean Aerosol Production (SOAP) experiment

    Science.gov (United States)

    Smith, Murray J.; Walker, Carolyn F.; Bell, Thomas G.; Harvey, Mike J.; Saltzman, Eric S.; Law, Cliff S.

    2018-04-01

    Direct measurements of marine dimethylsulfide (DMS) fluxes are sparse, particularly in the Southern Ocean. The Surface Ocean Aerosol Production (SOAP) voyage in February-March 2012 examined the distribution and flux of DMS in a biologically active frontal system in the southwest Pacific Ocean. Three distinct phytoplankton blooms were studied with oceanic DMS concentrations as high as 25 nmol L-1. Measurements of DMS fluxes were made using two independent methods: the eddy covariance (EC) technique using atmospheric pressure chemical ionization-mass spectrometry (API-CIMS) and the gradient flux (GF) technique from an autonomous catamaran platform. Catamaran flux measurements are relatively unaffected by airflow distortion and are made close to the water surface, where gas gradients are largest. Flux measurements were complemented by near-surface hydrographic measurements to elucidate physical factors influencing DMS emission. Individual DMS fluxes derived by EC showed significant scatter and, at times, consistent departures from the Coupled Ocean-Atmosphere Response Experiment gas transfer algorithm (COAREG). A direct comparison between the two flux methods was carried out to separate instrumental effects from environmental effects and showed good agreement with a regression slope of 0.96 (r2 = 0.89). A period of abnormal downward atmospheric heat flux enhanced near-surface ocean stratification and reduced turbulent exchange, during which GF and EC transfer velocities showed good agreement but modelled COAREG values were significantly higher. The transfer velocity derived from near-surface ocean turbulence measurements on a spar buoy compared well with the COAREG model in general but showed less variation. This first direct comparison between EC and GF fluxes of DMS provides confidence in compilation of flux estimates from both techniques, as well as in the stable periods when the observations are not well predicted by the COAREG model.

  14. Comparison of several databases of downward solar daily irradiation data at ocean surface with PIRATA measurements

    Science.gov (United States)

    Trolliet, Mélodie; Wald, Lucien

    2017-04-01

    The solar radiation impinging at sea surface is an essential variable in climate system. There are several means to assess the daily irradiation at surface, such as pyranometers aboard ship or on buoys, meteorological re-analyses and satellite-derived databases. Among the latter, assessments made from the series of geostationary Meteosat satellites offer synoptic views of the tropical and equatorial Atlantic Ocean every 15 min with a spatial resolution of approximately 5 km. Such Meteosat-derived databases are fairly recent and the quality of the estimates of the daily irradiation must be established. Efforts have been made for the land masses and must be repeated for the Atlantic Ocean. The Prediction and Research Moored Array in the Tropical Atlantic (PIRATA) network of moorings in the Tropical Atlantic Ocean is considered as a reference for oceanographic data. It consists in 17 long-term Autonomous Temperature Line Acquisition System (ATLAS) buoys equipped with sensors to measure near-surface meteorological and subsurface oceanic parameters, including downward solar irradiation. Corrected downward solar daily irradiation from PIRATA were downloaded from the NOAA web site and were compared to several databases: CAMS RAD, HelioClim-1, HelioClim-3 v4 and HelioClim-3 v5. CAMS-RAD, the CAMS radiation service, combines products of the Copernicus Atmosphere Monitoring Service (CAMS) on gaseous content and aerosols in the atmosphere together with cloud optical properties deduced every 15 min from Meteosat imagery to supply estimates of the solar irradiation. Part of this service is the McClear clear sky model that provides estimates of the solar irradiation that should be observed in cloud-free conditions. The second and third databases are HelioClim-1 and HelioClim-3 v4 that are derived from Meteosat images using the Heliosat-2 method and the ESRA clear sky model, based on the Linke turbidity factor. HelioClim-3 v5 is the fourth database and differs from v4 by the

  15. Monitoring and assessment of ocean acidification in the Arctic Ocean-A scoping paper

    Science.gov (United States)

    Robbins, Lisa L.; Yates, Kimberly K.; Feely, Richard; Fabry, Victoria

    2010-01-01

    Carbon dioxide (CO2) in the atmosphere is absorbed at the ocean surface by reacting with seawater to form a weak, naturally occurring acid called carbonic acid. As atmospheric carbon dioxide increases, the concentration of carbonic acid in seawater also increases, causing a decrease in ocean pH and carbonate mineral saturation states, a process known as ocean acidification. The oceans have absorbed approximately 525 billion tons of carbon dioxide from the atmosphere, or about one-quarter to one-third of the anthropogenic carbon emissions released since the beginning of the Industrial Revolution. Global surveys of ocean chemistry have revealed that seawater pH has decreased by about 0.1 units (from a pH of 8.2 to 8.1) since the 1700s due to absorption of carbon dioxide (Raven and others, 2005). Modeling studies, based on Intergovernmental Panel on Climate Change (IPCC) CO2 emission scenarios, predict that atmospheric carbon dioxide levels could reach more than 500 parts per million (ppm) by the middle of this century and 800 ppm by the year 2100, causing an additional decrease in surface water pH of 0.3 pH units. Ocean acidification is a global threat and is already having profound and deleterious effects on the geology, biology, chemistry, and socioeconomic resources of coastal and marine habitats. The polar and sub-polar seas have been identified as the bellwethers for global ocean acidification.

  16. Transport of contaminants by Arctic sea ice and surface ocean currents

    International Nuclear Information System (INIS)

    Pfirman, S.

    1995-01-01

    Sea ice and ocean currents transport contaminants in the Arctic from source areas on the shelves, to biologically active regions often more than a thousand kilometers away. Coastal regions along the Siberian margin are polluted by discharges of agricultural, industrial and military wastes in river runoff, from atmospheric deposition and ocean dumping. The Kara Sea is of particular concern because of deliberate dumping of radioactive waste, as well as the large input of polluted river water. Contaminants are incorporated in ice during suspension freezing on the shelves, and by atmospheric deposition during drift. Ice releases its contaminant load through brine drainage, surface runoff of snow and meltwater, and when the floe disintegrates. The marginal ice zone, a region of intense biological activity, may also be the site of major contaminant release. Potentially contaminated ice from the Kara Sea is likely to influence the marginal ice zones of the Barents and Greenland seas. From studies conducted to date it appears that sea ice from the Kara Sea does not typically enter the Beaufort Gyre, and thus is unlikely to affect the northern Canadian and Alaskan margins

  17. Multidentate-Protected Colloidal Gold Nanocrystals: pH Control of Cooperative Precipitation and Surface Layer Shedding

    Science.gov (United States)

    Kairdolf, Brad A.; Nie, Shuming

    2011-01-01

    Colloidal gold nanocrystals with broad size tunability and unusual pH-sensitive properties have been synthesized by using multidentate polymer ligands. Containing both carboxylic functional groups and sterically hindered aliphatic chains, the multidentate ligands are able to both reduce gold precursors and to stabilize gold nanoclusters during nucleation and growth. The “as-synthesized” nanocrystals are protected by an inner coordinating layer and an outer polymer layer, and are soluble in water and polar solvents. When the solution pH is lowered by just 0.6 units (from pH 4.85 to 4.25), the particles undergo a dramatic cooperative transition from being soluble to insoluble, allowing rapid isolation, purification, and redispersion of the multidentate-protected nanocrystals. A surprise finding is that when a portion of the surface carboxylate groups is neutralized by protonation, the particles irreversibly shed their outer polymer layer and become soluble in nonpolar organic solvents. Further, the multidentate polymer coatings are permeable to small organic molecules, in contrast to tightly packed self-assembled monolayers of alkanethiols on gold. These insights are important towards the design of “smart” imaging and therapeutic nanoparticles that are activated by small pH changes in the tumor interstitial space or endocytic organelles. PMID:21510704

  18. Surface area and the seabed area, volume, depth, slope, and topographic variation for the world's seas, oceans, and countries.

    Science.gov (United States)

    Costello, Mark John; Cheung, Alan; De Hauwere, Nathalie

    2010-12-01

    Depth and topography directly and indirectly influence most ocean environmental conditions, including light penetration and photosynthesis, sedimentation, current movements and stratification, and thus temperature and oxygen gradients. These parameters are thus likely to influence species distribution patterns and productivity in the oceans. They may be considered the foundation for any standardized classification of ocean ecosystems and important correlates of metrics of biodiversity (e.g., species richness and composition, fisheries). While statistics on ocean depth and topography are often quoted, how they were derived is rarely cited, and unless calculated using the same spatial resolution the resulting statistics will not be strictly comparable. We provide such statistics using the best available resolution (1-min) global bathymetry, and open source digital maps of the world's seas and oceans and countries' Exclusive Economic Zones, using a standardized methodology. We created a terrain map and calculated sea surface and seabed area, volume, and mean, standard deviation, maximum, and minimum, of both depth and slope. All the source data and our database are freely available online. We found that although the ocean is flat, and up to 71% of the area has a ocean volume exceeds 1.3 billion km(3) (or 1.3 sextillion liters), and sea surface and seabed areas over 354 million km(2). We propose the coefficient of variation of slope as an index of topographic heterogeneity. Future studies may improve on this database, for example by using a more detailed bathymetry, and in situ measured data. The database could be used to classify ocean features, such as abyssal plains, ridges, and slopes, and thus provide the basis for a standards based classification of ocean topography.

  19. A statistical-dynamical scheme for reconstructing ocean forcing in the Atlantic. Part I: weather regimes as predictors for ocean surface variables

    Energy Technology Data Exchange (ETDEWEB)

    Cassou, Christophe; Minvielle, Marie; Terray, Laurent [CERFACS/CNRS, Climate Modelling and Global Change Team, Toulouse (France); Perigaud, Claire [JPL-NASA, Ocean Science Element, Pasadena, CA (United States)

    2011-01-15

    The links between the observed variability of the surface ocean variables estimated from reanalysis and the overlying atmosphere decomposed in classes of large-scale atmospheric circulation via clustering are investigated over the Atlantic from 1958 to 2002. Daily 500 hPa geopotential height and 1,000 hPa wind anomaly maps are classified following a weather-typing approach to describe the North Atlantic and tropical Atlantic atmospheric dynamics, respectively. The algorithm yields patterns that correspond in the extratropics to the well-known North Atlantic-Europe weather regimes (NAE-WR) accounting for the barotropic dynamics, and in the tropics to wind classes (T-WC) representing the alteration of the trades. 10-m wind and 2-m temperature (T2) anomaly composites derived from regime/wind class occurrence are indicative of strong relationships between daily large-scale atmospheric circulation and ocean surface over the entire Atlantic basin. High temporal correlation values are obtained basin-wide at low frequency between the observed fields and their reconstruction by multiple linear regressions with the frequencies of occurrence of both NAE-WR and T-WC used as sole predictors. Additional multiple linear regressions also emphasize the importance of accounting for the strength of the daily anomalous atmospheric circulation estimated by the combined distances to all regimes centroids in order to reproduce the daily to interannual variability of the Atlantic ocean. We show that for most of the North Atlantic basin the occurrence of NAE-WR generally sets the sign of the ocean surface anomaly for a given day, and that the inter-regime distances are valuable predictors for the magnitude of that anomaly. Finally, we provide evidence that a large fraction of the low-frequency trends in the Atlantic observed at the surface over the last 50 years can be traced back, except for T2, to changes in occurrence of tropical and extratropical weather classes. All together, our

  20. Seasonal Variations of the Earth's Gravitational Field: An Analysis of Atmospheric Pressure, Ocean Tidal, and Surface Water Excitation

    Science.gov (United States)

    Dong, D,; Gross, R.S.; Dickey, J.

    1996-01-01

    Monthly mean gravitational field parameters (denoted here as C(sub even)) that represent linear combinations of the primarily even degree zonal spherical harmonic coefficients of the Earth's gravitational field have been recovered using LAGEOS I data and are compared with those derived from gridded global surface pressure data of the National meteorological center (NMC) spanning 1983-1992. The effect of equilibrium ocean tides and surface water variations are also considered. Atmospheric pressure and surface water fluctuations are shown to be the dominant cause of observed annual C(sub even) variations. Closure with observations is seen at the 1sigma level when atmospheric pressure, ocean tide and surface water effects are include. Equilibrium ocean tides are shown to be the main source of excitation at the semiannual period with closure at the 1sigma level seen when both atmospheric pressure and ocean tide effects are included. The inverted barometer (IB) case is shown to give the best agreement with the observation series. The potential of the observed C(sub even) variations for monitoring mass variations in the polar regions of the Earth and the effect of the land-ocean mask in the IB calculation are discussed.

  1. The importance of kinetics and redox in the biogeochemical cycling of iron in the surface ocean.

    Directory of Open Access Journals (Sweden)

    Peter L. Croot

    2012-06-01

    Full Text Available It is now well established that Iron (Fe is a limiting element in many regions of the open ocean. Our current understanding of the key processes which control iron distribution in the open ocean have been largely based on thermodynamic measurements performed under the assumption of equilibrium conditions. Using this equilibrium approach, researchers have been able to detect and quantify organic complexing ligands in seawater and examine their role in increasing the overall solubility of iron. Our current knowledge about iron bioavailability to phytoplankton and bacteria is also based heavily on carefully controlled laboratory studies where it is assumed the chemical species are in equilibrium in line with the free ion association model (FIAM and/or its successor the biotic ligand model (BLM. Similarly most field work on Fe biogeochemistry generally consists of a single profile which is in essence a ‘snap-shot’ in time of the system under investigation. However it is well known that the surface ocean is an extremely dynamic environment and it is unlikely if thermodynamic equilibrium between all the iron species present is ever truly achieved. In sunlit waters this is mostly due to the daily passage of the sun across the sky leading to photoredox processes which alter Fe speciation by cycling between redox states and between inorganic and organic species. Episodic deposition events, are also important perturbations to iron cycling as they bring new iron to the system altering the equilibrium between species and phases. Over the last 20 years the mesoscale iron enrichment experiments (e.g. IronEx I /II, SOIREE, EisenEx, SOFeX, EIFeX, SAGE, SEEDS and SERIES I /II and the FeCycle (I/II experiments have provided the first insights into processes altering iron speciation and distribution which occur over temporal scales of days to weeks. Here we utilize new field data collected in the open ocean on the redox and complexation kinetics of iron in the

  2. Transport and fate of hexachlorocyclohexanes in the oceanic air and surface seawater

    Directory of Open Access Journals (Sweden)

    Z. Xie

    2011-09-01

    Full Text Available Hexachlorocyclohexanes (HCHs are ubiquitous organic pollutants derived from pesticide application. They are subject to long-range transport, persistent in the environment, and capable of accumulation in biota. Shipboard measurements of HCH isomers (α-, γ- and β-HCH in surface seawater and boundary layer atmospheric samples were conducted in the Atlantic and the Southern Ocean in October to December of 2008. ΣHCHs concentrations (the sum of α-, γ- and β-HCH in the lower atmosphere ranged from 12 to 37 pg m−3 (mean: 27 ± 11 pg m−3 in the Northern Hemisphere (NH, and from 1.5 to 4.0 pg m−3 (mean: 2.8 ± 1.1 pg m−3 in the Southern Hemisphere (SH, respectively. Water concentrations were: α-HCH 0.33–47 pg l−1, γ-HCH 0.02–33 pg l−1 and β-HCH 0.11–9.5 pg l−1. Dissolved HCH concentrations decreased from the North Atlantic to the Southern Ocean, indicating historical use of HCHs in the NH. Spatial distribution showed increasing concentrations from the equator towards North and South latitudes illustrating the concept of cold trapping in high latitudes and less interhemispheric mixing process. In comparison to concentrations measured in 1987–1999/2000, gaseous HCHs were slightly lower, while dissolved HCHs decreased by factor of 2–3 orders of magnitude. Air-water exchange gradients suggested net deposition for α-HCH (mean: 3800 pg m−2 day−1 and γ-HCH (mean: 2000 pg m−2 day−1, whereas β-HCH varied between equilibrium (volatilization: <0–12 pg m−2 day−1 and net deposition (range: 6–690 pg m−2 day−1. Climate change may significantly accelerate the release of "old" HCHs from continental storage (e.g. soil, vegetation and high mountains and drive long-range transport from sources to deposition in the open oceans. Biological productivities may

  3. Surface plasmon resonance based fiber optic pH sensor utilizing Ag/ITO/Al/hydrogel layers.

    Science.gov (United States)

    Mishra, Satyendra K; Gupta, Banshi D

    2013-05-07

    The fabrication and characterization of a surface plasmon resonance based pH sensor using coatings of silver, ITO (In2O3:SnO2), aluminium and smart hydrogel layers over an unclad core of an optical fiber have been reported. The silver, aluminium and ITO layers were coated using a thermal evaporation technique, while the hydrogel layer was prepared using a dip-coating method. The sensor works on the principle of detecting changes in the refractive index of the hydrogel layer due to its swelling and shrinkage caused by changes in the pH of the fluid surrounding the hydrogel layer. The sensor utilizes a wavelength interrogation technique and operates in a particular window of low and high pH values. Increasing the pH value of the fluid causes swelling of the hydrogel layer, which decreases its refractive index and results in a shift of the resonance wavelength towards blue in the transmitted spectra. The thicknesses of the ITO and aluminium layers have been optimized to achieve the best performance of the sensor. The ITO layer increases the sensitivity while the aluminium layer increases the detection accuracy of the sensor. The proposed sensor possesses maximum sensitivity in comparison to the sensors reported in the literature. A negligible effect of ambient temperature in the range 25 °C to 45 °C on the performance of the sensor has been observed. The additional advantages of the sensor are short response time, low cost, probe miniaturization, probe re-usability and the capability of remote sensing.

  4. Coastal zone color scanner pigment concentrations in the southern ocean and relationships to geophysical surface features

    Science.gov (United States)

    Comiso, J. C.; Mcclain, C. R.; Sullivan, C. W.; Ryan, J. P.; Leonard, C. L.

    1993-01-01

    Climatological data on the distribution of surface pigment fields in the entire southern ocean over a seasonal cycle are examined. The occurrence of intense phytoplankton blooms during austral summer months and during other seasons in different regions is identified and analyzed. The highest pigment concentrations are observed at high latitudes and over regions with water depths usually less than 600 m. Basin-scale pigment distribution shows a slightly asymmetric pattern of enhanced pigment concentrations about Antarctica, with enhanced concentrations extending to lower latitudes in the Atlantic and Indian sectors than in the Pacific sector. A general increase in pigment concentrations is evident from the low latitudes toward the Antarctic circumpolar region. Spatial relationships between pigment and archived geophysical data reveal significant correlation between pigment distributions and both bathymetry and wind stress, while general hemispheric scale patterns of pigment distributions are most coherent with the geostrophic flow of the Antarctic Circumpolar Current.

  5. Surface Ocean Dispersion Observations from the Ship-Tethered Aerostat Remote Sensing System

    DEFF Research Database (Denmark)

    Carlson, Daniel Frazier; Ozgokmen, Tamay; Novelli, Guillaume

    2018-01-01

    Oil slicks and sheens reside at the air-sea interface, a region of the ocean that is notoriously difficult to measure and, therefore, little is known about the velocity field at the sea surface. The Ship-Tethered Aerostat Remote Sensing System (STARSS) was developed to measure Lagrangian velocities...... of experiments in the northern Gulf of Mexico in January- February 2016. STARSS was equipped with a GPS and inertial navigation system (INS) that was used to directly georectify the aerial images. A relative rectification technique was developed that translates and rotates the drift cards to minimize the total...... movement of all drift cards from one frame to the next. Rectified drift card positions were used to quantify scale-dependent dispersion by computing relative dispersion, relative diffusivity, and velocity structure functions. STARSS was part of a nested observational framework, which included deployments...

  6. Correlations Between Sea-Surface Salinity Tendencies and Freshwater Fluxes in the Pacific Ocean

    Science.gov (United States)

    Li, Zhen; Adamec, David

    2007-01-01

    Temporal changes in sea-surface salinity (SSS) from 21 years of a high resolution model integration of the Pacific Ocean are correlated with the freshwater flux that was used to force the integration. The correlations are calculated on a 1 x10 grid, and on a monthly scale to assess the possibility of deducing evaporation minus precipitation (E-P) fields from the salinity measurements to be taken by the upcoming Aquarius/SAC-D mission. Correlations between the monthly mean E-P fields and monthly mean SSS temporal tendencies are mainly zonally-oriented, and are highest where the local precipitation is relatively high. Nonseasonal (deviations from the monthly mean) correlations are highest along mid-latitude storm tracks and are relatively small in the tropics. The response of the model's surface salinity to surface forcing is very complex, and retrievals of freshwater fluxes from SSS measurements alone will require consideration of other processes, including horizontal advection and vertical mixing, rather than a simple balance between the two.

  7. How well will the Surface Water and Ocean Topography (SWOT) mission observe global reservoirs?

    Science.gov (United States)

    Solander, Kurt C.; Reager, John T.; Famiglietti, James S.

    2016-03-01

    Accurate observations of global reservoir storage are critical to understand the availability of managed water resources. By enabling estimates of surface water area and height for reservoir sizes exceeding 250 m2 at a maximum repeat orbit of up to 21 days, the NASA Surface Water and Ocean Topography (SWOT) satellite mission (anticipated launch date 2020) is expected to greatly improve upon existing reservoir monitoring capabilities. It is thus essential that spatial and temporal measurement uncertainty for water bodies is known a priori to maximize the utility of SWOT observations as the data are acquired. In this study, we evaluate SWOT reservoir observations using a three-pronged approach that assesses temporal aliasing, errors due to specific reservoir spatial properties, and SWOT performance over actual reservoirs using a combination of in situ and simulated reservoir observations from the SWOTsim instrument simulator. Results indicate temporal errors to be less than 5% for the smallest reservoir sizes (100 km2). Surface area and height errors were found to be minimal (area SWOT, this study will be have important implications for future applications of SWOT reservoir measurements in global monitoring systems and models.

  8. Reconstructing extreme AMOC events through nudging of the ocean surface: a perfect model approach

    Science.gov (United States)

    Ortega, Pablo; Guilyardi, Eric; Swingedouw, Didier; Mignot, Juliette; Nguyen, Sébastien

    2017-11-01

    While the Atlantic Meridional Overturning Circulation (AMOC) is thought to be a crucial component of the North Atlantic climate, past changes in its strength are challenging to quantify, and only limited information is available. In this study, we use a perfect model approach with the IPSL-CM5A-LR model to assess the performance of several surface nudging techniques in reconstructing the variability of the AMOC. Special attention is given to the reproducibility of an extreme positive AMOC peak from a preindustrial control simulation. Nudging includes standard relaxation techniques towards the sea surface temperature and salinity anomalies of this target control simulation, and/or the prescription of the wind-stress fields. Surface nudging approaches using standard fixed restoring terms succeed in reproducing most of the target AMOC variability, including the timing of the extreme event, but systematically underestimate its amplitude. A detailed analysis of the AMOC variability mechanisms reveals that the underestimation of the extreme AMOC maximum comes from a deficit in the formation of the dense water masses in the main convection region, located south of Iceland in the model. This issue is largely corrected after introducing a novel surface nudging approach, which uses a varying restoring coefficient that is proportional to the simulated mixed layer depth, which, in essence, keeps the restoring time scale constant. This new technique substantially improves water mass transformation in the regions of convection, and in particular, the formation of the densest waters, which are key for the representation of the AMOC extreme. It is therefore a promising strategy that may help to better constrain the AMOC variability and other ocean features in the models. As this restoring technique only uses surface data, for which better and longer observations are available, it opens up opportunities for improved reconstructions of the AMOC over the last few decades.

  9. An explanation for the different climate sensitivities of land and ocean surfaces based on the diurnal cycle

    Directory of Open Access Journals (Sweden)

    A. Kleidon

    2017-09-01

    Full Text Available Observations and climate model simulations consistently show a higher climate sensitivity of land surfaces compared to ocean surfaces. Here we show that this difference in temperature sensitivity can be explained by the different means by which the diurnal variation in solar radiation is buffered. While ocean surfaces buffer the diurnal variations by heat storage changes below the surface, land surfaces buffer it mostly by heat storage changes above the surface in the lower atmosphere that are reflected in the diurnal growth of a convective boundary layer. Storage changes below the surface allow the ocean surface–atmosphere system to maintain turbulent fluxes over day and night, while the land surface–atmosphere system maintains turbulent fluxes only during the daytime hours, when the surface is heated by absorption of solar radiation. This shorter duration of turbulent fluxes on land results in a greater sensitivity of the land surface–atmosphere system to changes in the greenhouse forcing because nighttime temperatures are shaped by radiative exchange only, which are more sensitive to changes in greenhouse forcing. We use a simple, analytic energy balance model of the surface–atmosphere system in which turbulent fluxes are constrained by the maximum power limit to estimate the effects of these different means to buffer the diurnal cycle on the resulting temperature sensitivities. The model predicts that land surfaces have a 50 % greater climate sensitivity than ocean surfaces, and that the nighttime temperatures on land increase about twice as much as daytime temperatures because of the absence of turbulent fluxes at night. Both predictions compare very well with observations and CMIP5 climate model simulations. Hence, the greater climate sensitivity of land surfaces can be explained by its buffering of diurnal variations in solar radiation in the lower atmosphere.

  10. Atmosphere surface storm track response to resolved ocean mesoscale in two sets of global climate model experiments

    Science.gov (United States)

    Small, R. Justin; Msadek, Rym; Kwon, Young-Oh; Booth, James F.; Zarzycki, Colin

    2018-05-01

    It has been hypothesized that the ocean mesoscale (particularly ocean fronts) can affect the strength and location of the overlying extratropical atmospheric storm track. In this paper, we examine whether resolving ocean fronts in global climate models indeed leads to significant improvement in the simulated storm track, defined using low level meridional wind. Two main sets of experiments are used: (i) global climate model Community Earth System Model version 1 with non-eddy-resolving standard resolution or with ocean eddy-resolving resolution, and (ii) the same but with the GFDL Climate Model version 2. In case (i), it is found that higher ocean resolution leads to a reduction of a very warm sea surface temperature (SST) bias at the east coasts of the U.S. and Japan seen in standard resolution models. This in turn leads to a reduction of storm track strength near the coastlines, by up to 20%, and a better location of the storm track maxima, over the western boundary currents as observed. In case (ii), the change in absolute SST bias in these regions is less notable, and there are modest (10% or less) increases in surface storm track, and smaller changes in the free troposphere. In contrast, in the southern Indian Ocean, case (ii) shows most sensitivity to ocean resolution, and this coincides with a larger change in mean SST as ocean resolution is changed. Where the ocean resolution does make a difference, it consistently brings the storm track closer in appearance to that seen in ERA-Interim Reanalysis data. Overall, for the range of ocean model resolutions used here (1° versus 0.1°) we find that the differences in SST gradient have a small effect on the storm track strength whilst changes in absolute SST between experiments can have a larger effect. The latter affects the land-sea contrast, air-sea stability, surface latent heat flux, and the boundary layer baroclinicity in such a way as to reduce storm track activity adjacent to the western boundary in the N

  11. A Novel Low-cost, Ka-band, High Altitude, Multi-Baseline Unmanned Aerial Vehicle Sensor for Surface Water Ocean Topography, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The NRC Decadal Survey recommended the Surface Water Ocean Topography (SWOT) satellite mission to address terrestrial fresh water hydrology and physical oceanography...

  12. Ocean Surface Topography Mission (OSTM) /Jason-2: Level-2 Geophysical Data Records (GDR) (NODC Accession 0043269)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — OSTM/JASON-2 is a follow-on mission continuing the TOPEX/Poseidon and Jason-1, and is designed to ensure continuity of high quality measurements for ocean science...

  13. Ocean Surface Topography Mission (OSTM) /Jason-2 Data Collection, 2008-present (NODC Accession 0118277)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — OSTM/JASON-2 is a follow-on mission continuing the TOPEX/Poseidon and Jason-1, and is designed to ensure continuity of high quality measurements for ocean science...

  14. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Micro-porous membrane equilibrator and other instruments from WAKATAKA MARU in the North Atlantic Ocean, North Pacific Ocean and South Atlantic Ocean from 2011-06-10 to 2011-12-06 (NCEI Accession 0157428)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157428 includes Surface underway, chemical, meteorological and physical data collected from WAKATAKA MARU in the North Atlantic Ocean, North Pacific...

  15. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2009-12-29 to 2010-12-20 (NCEI Accession 0156926)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0156926 includes Surface underway, chemical, meteorological and physical data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South...

  16. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from LAURENCE M. GOULD in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2012-12-31 to 2013-12-19 (NCEI Accession 0163187)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0163187 includes chemical, meteorological, physical and surface underway data collected from LAURENCE M. GOULD in the South Atlantic Ocean, South...

  17. Gradient flux measurements of sea–air DMS transfer during the Surface Ocean Aerosol Production (SOAP experiment

    Directory of Open Access Journals (Sweden)

    M. J. Smith

    2018-04-01

    Full Text Available Direct measurements of marine dimethylsulfide (DMS fluxes are sparse, particularly in the Southern Ocean. The Surface Ocean Aerosol Production (SOAP voyage in February–March 2012 examined the distribution and flux of DMS in a biologically active frontal system in the southwest Pacific Ocean. Three distinct phytoplankton blooms were studied with oceanic DMS concentrations as high as 25 nmol L−1. Measurements of DMS fluxes were made using two independent methods: the eddy covariance (EC technique using atmospheric pressure chemical ionization–mass spectrometry (API-CIMS and the gradient flux (GF technique from an autonomous catamaran platform. Catamaran flux measurements are relatively unaffected by airflow distortion and are made close to the water surface, where gas gradients are largest. Flux measurements were complemented by near-surface hydrographic measurements to elucidate physical factors influencing DMS emission. Individual DMS fluxes derived by EC showed significant scatter and, at times, consistent departures from the Coupled Ocean–Atmosphere Response Experiment gas transfer algorithm (COAREG. A direct comparison between the two flux methods was carried out to separate instrumental effects from environmental effects and showed good agreement with a regression slope of 0.96 (r2 = 0.89. A period of abnormal downward atmospheric heat flux enhanced near-surface ocean stratification and reduced turbulent exchange, during which GF and EC transfer velocities showed good agreement but modelled COAREG values were significantly higher. The transfer velocity derived from near-surface ocean turbulence measurements on a spar buoy compared well with the COAREG model in general but showed less variation. This first direct comparison between EC and GF fluxes of DMS provides confidence in compilation of flux estimates from both techniques, as well as in the stable periods when the observations are not well predicted by the COAREG

  18. Solutions Network Formulation Report: Improving NOAA's PORTS(R) Through Enhanced Data Inputs from NASA's Ocean Surface Topography Mission

    Science.gov (United States)

    Guest, DeNeice

    2007-01-01

    The Nation uses water-level data for a variety of practical purposes, including nautical charting, maritime navigation, hydrography, coastal engineering, and tsunami and storm surge warnings. Long-term applications include marine boundary determinations, tidal predictions, sea-level trend monitoring, oceanographic research, and climate research. Accurate and timely information concerning sea-level height, tide, and ocean current is needed to understand their impact on coastal management, disaster management, and public health. Satellite altimeter data products are currently used by hundreds of researchers and operational users to monitor ocean circulation and to improve scientists understanding of the role of the oceans in climate and weather. The NOAA (National Oceanic and Atmospheric Administration) National Ocean Service has been monitoring sea-level variations for many years. NOAA s PORTS (Physical Oceanographic Real-Time System) DST (decision support tool), managed by the Center for Operational Oceanographic Products and Services, supports safe and cost-efficient navigation by providing ship masters and pilots with accurate real-time information required to avoid groundings and collisions. This report assesses the capacity of NASA s satellite altimeter data to meet societal decision support needs through incorporation into NOAA s PORTS. NASA has a long heritage of collecting data for ocean research, including its current Terra and Aqua missions. Numerous other missions provide additional important information for coastal management issues, and data collection will continue in the coming decade with such missions as the OSTM (Ocean Surface Topography Mission). OSTM will provide data on sea-surface heights for determining ocean circulation, climate change, and sea-level rise. We suggest that NASA incorporate OSTM altimeter data (C- and Ku-band) into NOAA s PORTS DST in support of NASA s Coastal Management National Application with secondary support to the

  19. Near 7-day response of ocean bottom pressure to atmospheric surface pressure and winds in the northern South China Sea

    Science.gov (United States)

    Zhang, Kun; Zhu, Xiao-Hua; Zhao, Ruixiang

    2018-02-01

    Ocean bottom pressures, observed by five pressure-recording inverted echo sounders (PIESs) from October 2012 to July 2014, exhibit strong near 7-day variability in the northern South China Sea (SCS) where long-term in situ bottom pressure observations are quite sparse. This variability was strongest in October 2013 during the near two years observation period. By joint analysis with European Center for Medium-Range Weather Forecasts (ECMWF) data, it is shown that the near 7-day ocean bottom pressure variability is closely related to the local atmospheric surface pressure and winds. Within a period band near 7 days, there are high coherences, exceeding 95% significance level, of observed ocean bottom pressure with local atmospheric surface pressure and with both zonal and meridional components of the wind. Ekman pumping/suction caused by the meridional component of the wind in particular, is suggested as one driving mechanism. A Kelvin wave response to the near 7-day oscillation would propagate down along the continental slope, observed at the Qui Nhon in the Vietnam. By multiple and partial coherence analyses, we find that local atmospheric surface pressure and Ekman pumping/suction show nearly equal influence on ocean bottom pressure variability at near 7-day periods. A schematic diagram representing an idealized model gives us a possible mechanism to explain the relationship between ocean bottom pressure and local atmospheric forcing at near 7-day periods in the northern SCS.

  20. Optimization of pH sensing using silicon nanowire field effect transistors with HfO2 as the sensing surface

    International Nuclear Information System (INIS)

    Zafar, Sufi; D'Emic, Christopher; Afzali, Ali; Fletcher, Benjamin; Zhu, Y; Ning, Tak

    2011-01-01

    Silicon nanowire field effect transistor sensors with SiO 2 /HfO 2 as the gate dielectric sensing surface are fabricated using a top down approach. These sensors are optimized for pH sensing with two key characteristics. First, the pH sensitivity is shown to be independent of buffer concentration. Second, the observed pH sensitivity is enhanced and is equal to the Nernst maximum sensitivity limit of 59 mV/pH with a corresponding subthreshold drain current change of ∼ 650%/pH. These two enhanced pH sensing characteristics are attributed to the use of HfO 2 as the sensing surface and an optimized fabrication process compatible with silicon processing technology.

  1. Optimization of pH sensing using silicon nanowire field effect transistors with HfO2 as the sensing surface.

    Science.gov (United States)

    Zafar, Sufi; D'Emic, Christopher; Afzali, Ali; Fletcher, Benjamin; Zhu, Y; Ning, Tak

    2011-10-07

    Silicon nanowire field effect transistor sensors with SiO(2)/HfO(2) as the gate dielectric sensing surface are fabricated using a top down approach. These sensors are optimized for pH sensing with two key characteristics. First, the pH sensitivity is shown to be independent of buffer concentration. Second, the observed pH sensitivity is enhanced and is equal to the Nernst maximum sensitivity limit of 59 mV/pH with a corresponding subthreshold drain current change of ∼ 650%/pH. These two enhanced pH sensing characteristics are attributed to the use of HfO(2) as the sensing surface and an optimized fabrication process compatible with silicon processing technology.

  2. Non-monotonic swelling of surface grafted hydrogels induced by pH and/or salt concentration

    Science.gov (United States)

    Longo, Gabriel S.; Olvera de la Cruz, Monica; Szleifer, I.

    2014-09-01

    We use a molecular theory to study the thermodynamics of a weak-polyacid hydrogel film that is chemically grafted to a solid surface. We investigate the response of the material to changes in the pH and salt concentration of the buffer solution. Our results show that the pH-triggered swelling of the hydrogel film has a non-monotonic dependence on the acidity of the bath solution. At most salt concentrations, the thickness of the hydrogel film presents a maximum when the pH of the solution is increased from acidic values. The quantitative details of such swelling behavior, which is not observed when the film is physically deposited on the surface, depend on the molecular architecture of the polymer network. This swelling-deswelling transition is the consequence of the complex interplay between the chemical free energy (acid-base equilibrium), the electrostatic repulsions between charged monomers, which are both modulated by the absorption of ions, and the ability of the polymer network to regulate charge and control its volume (molecular organization). In the absence of such competition, for example, for high salt concentrations, the film swells monotonically with increasing pH. A deswelling-swelling transition is similarly predicted as a function of the salt concentration at intermediate pH values. This reentrant behavior, which is due to the coupling between charge regulation and the two opposing effects triggered by salt concentration (screening electrostatic interactions and charging/discharging the acid groups), is similar to that found in end-grafted weak polyelectrolyte layers. Understanding how to control the response of the material to different stimuli, in terms of its molecular structure and local chemical composition, can help the targeted design of applications with extended functionality. We describe the response of the material to an applied pressure and an electric potential. We present profiles that outline the local chemical composition of the

  3. Simulation of the Impact of New Ocean Surface Wind Measurements on H*Wind Analyses

    Science.gov (United States)

    Miller, Timothy; Atlas, Robert; Black, Peter; Chen, Shuyi; Hood, Robbie; Johnson, James; Jones, Linwood; Ruf, Chris; Uhlhorn, Eric

    2008-01-01

    The H*Wind analysis, a product of the Hurricane Research Division of NOAA's Atlantic Oceanographic and Meteorological Laboratory, brings together wind measurements from a variety of observation platforms into an objective analysis of the distribution of surface wind speeds in a tropical cyclone. This product is designed to improve understanding of the extent and strength of the wind field, and to improve the assessment of hurricane intensity. See http://www.aoml.noaa.gov/hrd/data sub/wind.html. The Hurricane Imaging Radiometer (HIRAD) is a new passive microwave remote sensor for hurricane observations that is currently under development by NASA Marshall Space Flight Center, NOAA Hurricane Research Division, the University of Central Florida and the University of Michigan. HIRAD is being designed to enhance the current real-time airborne ocean surface winds observation capabilities of NOAA and USAF Weather Squadron hurricane hunter aircraft using the operational airbome Stepped Frequency Microwave Radiometer (SFMR). Unlike SFMR, which measures wind speed and rain rate along the ground track directly beneath the aircraft, HIRAD will provide images of the surface wind and rain field over a wide swath (approximately 3 x the aircraft altitude, or approximately 2 km from space). The instrument is described in a separate paper presented at this conference. The present paper describes a set of Observing System Simulation Experiments (OSSEs) in which measurements from the new instrument as well as those from existing instruments (air, surface, and space-based) are simulated from the output of a numerical model from the University of Miami, and those results are used to construct H*Wind analyses. Evaluations will be presented on the relative impact of HIRAD and other instruments on H*Wind analyses, including the use of HIRAD from 2 aircraft altitudes and from a space-based platform.

  4. Redox properties of phenosafranine at zeolite-modified electrodes-Effect of surface modification and solution pH

    International Nuclear Information System (INIS)

    Easwaramoorthi, S.; Natarajan, P.

    2008-01-01

    Redox properties of cationic dye phenosafranine (3,7-diamino-5-phenylphenazenium chloride) (PS + ) were studied at zeolite-modified electrodes using Zeolite-Y and NaZSM-5. The peak current and peak potential of phenosafranine-adsorbed zeolite were found to be influenced by the pH of the electrolyte solution. Observation of a second redox couple is suggested to be due to formation of new species at low concentration from the reduced phenosafranine at the zeolite-modified electrodes. Titanium dioxide nanoparticles encapsulated in the cavities of the zeolite or anchored on the external surface of the zeolite do not seem to affect the redox properties of adsorbed PS + . When the cyclic voltammograms are recorded immediately after the electrode is immersed into the solution, the redox potential of PS + is found to be sensitive to the nature of the zeolite surface. The peak potential shifts towards positive region under continuous cycles as the surface hydroxyl groups get protonated in acidic electrolyte solution thereby forcing the movement of dye molecules from the zeolite surface to the zeolite electrode solution interface. The electron transfer rate constants for the adsorbed dye at the electrode are calculated to be 2.5 ± 0.2 s -1 and 3.5 ± 0.2 s -1 for the zeolite-Y electrode and the ZSM-5 electrode, respectively by the Laviron equation

  5. Effect of growth at low pH on the cell surface properties of a typical strain of Lactobacillus casei group.

    Science.gov (United States)

    Hossein Nezhad, M; Stenzel, Dj; Britz, Ml

    2010-09-01

    Although members of the Lactobacillus casei group are known to survive under acidic conditions, the underlying mechanisms of growth at acidic condition and the impact of low pH on the relative level of protein expression at the cell surface remain poorly studied. After confirming the taxonomy of L. casei strain GCRL 12 which was originally isolated from cheese and confirmed by 16S rRNA sequence analysis, the impact of acidic pH on growth rate was determined. Late log-phase cells cultured at pH 4.0 showed obvious changes in Gram staining properties while transmission electron microscopy analysis revealed evidence of structural distortions of the cell surface relative to the controls cultured at pH 6.5. When comparing cytosolic or whole cell preparations on SDS-PAGE, few changes in protein profiles were observed under the two growth conditions. However, analysis of surface protein extracted by 5M LiCl demonstrated changes in the proportions of proteins present in the molecular weight range of 10 to 80 kDa, with some proteins more dominant at pH 6.5 and other at pH 4. These data suggest that surface proteins of this strain are associated with growth and survival at low pH. The function of these proteins is subject to further investigation.

  6. Dissolved inorganic carbon, pH, temperature, salinity and other variables collected from time series and surface observations using Moored Autonomous Dissolved Inorganic Carbon (MADIC) System, Sunburst SAMI2 pH sensor, and other instruments from Kewalo Buoy near the coast of Honolulu, Hawaii from 2013-10-31 to 2014-06-15 (NCEI Accession 0132048)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To expand the number of tools available for autonomous carbonate system observations, we have developed a robust surface ocean dissolved inorganic carbon (DIC)...

  7. Damping of surface waves due to oil emulsions in application to ocean remote sensing

    Science.gov (United States)

    Sergievskaya, I.; Ermakov, S.; Lazareva, T.; Lavrova, O.

    2017-10-01

    Applications of different radar and optical methods for detection of oil pollutions based on the effect of damping of short wind waves by surface films have been extensively studied last decades. The main problem here is poor knowledge of physical characteristics of oil films, in particular, emulsified oil layers (EOL). The latter are ranged up to 70% of all pollutants. Physical characteristics of EOL which are responsible for wave damping and respectively for possibilities of their remote sensing depend on conditions of emulsification processes, e.g., mixing due to wave breaking, on percentage of water in the oil, etc. and are not well studied by now. In this paper results of laboratory studies of damping of gravity-capillary waves due to EOL on water are presented and compared to oil layers (OL). A laboratory method used previously for monomolecular films and OL, and based on measuring the damping coefficient and wavelength of parametrically generated standing waves has been applied for determination of EOL characteristics. Investigations of characteristics of crude oil, oil emulsions and crude OL and EOL have been carried out in a wide range of surface wave frequencies (from 10 to 25 Hz) and OL and EOL film thickness (from hundredths of millimeter to a few millimeters. The selected frequency range corresponds to Bragg waves for microwave, X- to Ka-band radars typically used for ocean remote sensing. An effect of enhanced wave damping due to EOL compared to non emulsified crude OL is revealed.

  8. Response of the North Atlantic surface and intermediate ocean structure to climate warming of MIS 11.

    Science.gov (United States)

    Kandiano, Evgenia S; van der Meer, Marcel T J; Schouten, Stefan; Fahl, Kirsten; Sinninghe Damsté, Jaap S; Bauch, Henning A

    2017-04-10

    Investigating past interglacial climates not only help to understand how the climate system operates in general, it also forms a vital basis for climate predictions. We reconstructed vertical stratification changes in temperature and salinity in the North Atlantic for a period some 400 ka ago (MIS11), an interglacial time analogue of a future climate. As inferred from a unique set of biogeochemical, geochemical, and faunal data, the internal upper ocean stratification across MIS 11 shows distinct depth-dependent dynamical changes related to vertical as well as lateral shifts in the upper Atlantic meridional circulation system. Importantly, transient cold events are recognized near the end of the long phase of postglacial warming at surface, subsurface, mid, and deeper water layers. These data demonstrate that MIS 11 coolings over the North Atlantic were initially triggered by freshwater input at the surface and expansion of cold polar waters into the Subpolar Gyre. The cooling signal was then transmitted downwards into mid-water depths. Since the cold events occurred after the main deglacial phase we suggest that their cause might be related to continuous melting of the Greenland ice sheet, a mechanism that might also be relevant for the present and upcoming climate.

  9. Hourly changes in sea surface salinity in coastal waters recorded by Geostationary Ocean Color Imager

    Science.gov (United States)

    Liu, Rongjie; Zhang, Jie; Yao, Haiyan; Cui, Tingwei; Wang, Ning; Zhang, Yi; Wu, Lingjuan; An, Jubai

    2017-09-01

    In this study, we monitored hourly changes in sea surface salinity (SSS) in turbid coastal waters from geostationary satellite ocean color images for the first time, using the Bohai Sea as a case study. We developed a simple multi-linear statistical regression model to retrieve SSS data from Geostationary Ocean Color Imager (GOCI) based on an in situ satellite matched-up dataset (R2 = 0.795; N = 41; Range: 26.4 to 31.9 psμ). The model was then validated using independent continuous SSS measurements from buoys, with the average percentage difference of 0.65%. The model was applied to GOCI images from the dry season during an astronomical tide to characterize hourly changes in SSS in the Bohai Sea. We found that the model provided reasonable estimates of the hourly changes in SSS and that trends in the modeled and measured data were similar in magnitude and direction (0.43 vs 0.33 psμ, R2 = 0.51). There were clear diurnal variations in the SSS of the Bohai Sea, with a regional average of 0.455 ± 0.079 psμ (0.02-3.77 psμ). The magnitude of the diurnal variations in SSS varied spatially, with large diurnal variability in the nearshore, particularly in the estuary, and small variability in the offshore area. The model for the riverine area was based on the inverse correlation between SSS and CDOM absorption. In the offshore area, the water mass of the North Yellow Sea, characterized by high SSS and low CDOM concentrations, dominated. Analysis of the driving mechanisms showed that the tidal current was the main control on hourly changes in SSS in the Bohai Sea.

  10. The pH dependent surface charging and points of zero charge. VII. Update.

    Science.gov (United States)

    Kosmulski, Marek

    2018-01-01

    The pristine points of zero charge (PZC) and isoelectric points (IEP) of metal oxides and IEP of other materials from the recent literature, and a few older results (overlooked in previous searches) are summarized. This study is an update of the previous compilations by the same author [Surface Charging and Points of Zero Charge, CRC, Boca Raton, 2009; J. Colloid Interface Sci. 337 (2009) 439; 353 (2011) 1; 426 (2014) 209]. The field has been very active, but most PZC and IEP are reported for materials, which are very well-documented already (silica, alumina, titania, iron oxides). IEP of (nominally) Gd 2 O 3 , NaTaO 3 , and SrTiO 3 have been reported in the recent literature. Their IEP were not reported in older studies. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Surface pH changes suggest a role for H+/OH- channels in salinity response of Chara australis.

    Science.gov (United States)

    Absolonova, Marketa; Beilby, Mary J; Sommer, Aniela; Hoepflinger, Marion C; Foissner, Ilse

    2018-05-01

    To understand salt stress, the full impact of salinity on plant cell physiology has to be resolved. Electrical measurements suggest that salinity inhibits the proton pump and opens putative H + /OH - channels all over the cell surface of salt sensitive Chara australis (Beilby and Al Khazaaly 2009; Al Khazaaly and Beilby 2012). The channels open transiently at first, causing a characteristic noise in membrane potential difference (PD), and after longer exposure remain open with a typical current-voltage (I/V) profile, both abolished by the addition of 1 mM ZnCl 2 , the main known blocker of animal H + channels. The cells were imaged with confocal microscopy, using fluorescein isothiocyanate (FITC) coupled to dextran 70 to illuminate the pH changes outside the cell wall in artificial fresh water (AFW) and in saline medium. In the early saline exposure, we observed alkaline patches (bright fluorescent spots) appearing transiently in random spatial distribution. After longer exposure, some of the spots became fixed in space. Saline also abolished or diminished the pH banding pattern observed in the untreated control cells. ZnCl 2 suppressed the alkaline spot formation in saline and the pH banding pattern in AFW. The osmotic component of the saline stress did not produce transient bright spots or affect banding. The displacement of H + from the cell wall charges, the H + /OH - channel conductance/density, and self-organization are discussed. No homologies to animal H + channels were found. Salinity activation of the H + /OH - channels might contribute to saline response in roots of land plants and leaves of aquatic angiosperms.

  12. Trends in Arctic Ocean bottom pressure, sea surface height and freshwater content using GRACE and the ice-ocean model PIOMAS from 2008-2012

    Science.gov (United States)

    Peralta-Ferriz, Cecilia; Morison, James; Zhang, Jinlun; Bonin, Jennifer

    2014-05-01

    The variability of ocean bottom pressure (OBP) in the Arctic is dominated by the variations in sea surface height (SSH) from daily to monthly timescales. Conversely, OBP variability is dominated by the changes in the steric pressure (StP) at inter-annual timescales, particularly off the continental shelves. The combination of GRACE-derived ocean bottom pressure and ICESat altimetry-derived sea surface height variations in the Arctic Ocean have provided new means of identifying inter-annual trends in StP (StP = OBP-SSH) and associated freshwater content (FWC) of the Arctic region (Morison et al., 2012). Morison et al. (2012) showed that from 2004 to 2008, the FWC increased in the Beaufort Gyre and decreased in the Siberian and Central Arctic, resulting in a relatively small net basin-averaged FWC change. In this work, we investigate the inter-annual trends from 2008 to 2012 in OBP from GRACE, SSH from the state-of-the-art pan-Arctic ocean model PIOMAS -validated with tide and pressure gauges in the Arctic-, and compute the trends in StP and FWC from 2008-2012. We compare these results with the previous trends from 2005-2008 described in Morison et al. (2012). Our initial findings suggest increased salinity in the entire Arctic basin (relative to the climatological seasonal variation) from 2008-2012, compared to the preceding four years (2005-2008). We also find that the trends in OBP, SSH and StP from 2008-2012 present a different behavior during the spring-summer and fall-winter, unlike 2005-2008, in which the trends were generally consistent through all months of the year. It seems since 2009, when the Beaufort Gyre relaxed and the export of freshwater from the Canada Basin into the Canadian Archipelago and Fram Strait, via the Lincoln Sea, was anomalously large (de Steur et al., 2013), the Arctic Ocean has entered a new circulation regime. The causes of such changes in the inter-annual trends of OBP, SSH and StP -hence FWC-, associated with the changes in the

  13. Sea surface height determination in the arctic ocean from Cryosat2 SAR data, the impact of using different empirical retrackers

    DEFF Research Database (Denmark)

    Jain, Maulik; Andersen, Ole Baltazar; Stenseng, Lars

    2012-01-01

    Cryosat2 Level 1B SAR data can be processed using different empirical retrackers to determine the sea surface height and its variations in the Arctic Ocean. Two improved retrackers based on the combination of OCOG (Offset Centre of Gravity), Threshold methods and Leading Edge Retrieval is used...

  14. On the role of surface heat budget parameters over the tropical Indian Ocean in relation to the summer monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    RameshKumar, M.R.; Sastry, J.S.

    This study presents the role of sea surface temperature (SST) in the Arabian Sea and Bay of Bengal, cloud motion vector winds in the Equatorial Indian Ocean, and the cold fronts in the South Africa-Malagassy region on the onset and quantum...

  15. Automated River Reach Definition Strategies: Applications for the Surface Water and Ocean Topography Mission

    Science.gov (United States)

    Frasson, Renato Prata de Moraes; Wei, Rui; Durand, Michael; Minear, J. Toby; Domeneghetti, Alessio; Schumann, Guy; Williams, Brent A.; Rodriguez, Ernesto; Picamilh, Christophe; Lion, Christine; Pavelsky, Tamlin; Garambois, Pierre-André

    2017-10-01

    The upcoming Surface Water and Ocean Topography (SWOT) mission will measure water surface heights and widths for rivers wider than 100 m. At its native resolution, SWOT height errors are expected to be on the order of meters, which prevent the calculation of water surface slopes and the use of slope-dependent discharge equations. To mitigate height and width errors, the high-resolution measurements will be grouped into reaches (˜5 to 15 km), where slope and discharge are estimated. We describe three automated river segmentation strategies for defining optimum reaches for discharge estimation: (1) arbitrary lengths, (2) identification of hydraulic controls, and (3) sinuosity. We test our methodologies on 9 and 14 simulated SWOT overpasses over the Sacramento and the Po Rivers, respectively, which we compare against hydraulic models of each river. Our results show that generally, height, width, and slope errors decrease with increasing reach length. However, the hydraulic controls and the sinuosity methods led to better slopes and often height errors that were either smaller or comparable to those of arbitrary reaches of compatible sizes. Estimated discharge errors caused by the propagation of height, width, and slope errors through the discharge equation were often smaller for sinuosity (on average 8.5% for the Sacramento and 6.9% for the Po) and hydraulic control (Sacramento: 7.3% and Po: 5.9%) reaches than for arbitrary reaches of comparable lengths (Sacramento: 8.6% and Po: 7.8%). This analysis suggests that reach definition methods that preserve the hydraulic properties of the river network may lead to better discharge estimates.

  16. Corrosion and biofouling on the non-heat-exchanger surfaces of an ocean thermal energy conversion power plant: a survey

    Energy Technology Data Exchange (ETDEWEB)

    Castelli, V.J. (ed.)

    1979-05-01

    Of the many foreseeable problems confronting economical ocean thermal energy conversion operation, two major items are the deterioration of the structural and functional components, which prevents efficient operation, and the biofouling of the surfaces, which adds excess weight to the floating ocean platform. The techniques required for effective long-term control of deterioration and corrosion have been investigated actively for many years, and successful solutions for most situations have been developed. For the most part, these solutions can be directly transferred to the ocean thermal energy conversion plant. The majority of problems in these areas are expected to be associated with scale-up and will require some advanced development due to the immensity of the ocean thermal energy conversion platform. Current antifouling control systems are not effective for long-term fouling prevention. Commercially available antifouling coatings are limited to a 3-year service life in temperate waters, and even shorter in tropical waters. However, underwater cleaning techniques and some fouling-control systems presently being used by conventional power plants may find utility on an ocean thermal energy conversion plant. In addition, some recent major advances in long-term antifouling coatings sponsored by the Navy may be applicable to ocean thermal energy conversion. 132 references.

  17. Evaluation of the Ca ion release, pH and surface apatite formation of a prototype tricalcium silicate cement.

    Science.gov (United States)

    Yamamoto, S; Han, L; Noiri, Y; Okiji, T

    2017-12-01

    To evaluate the Ca 2+ -releasing, alkalizing and apatite-like surface precipitate-forming abilities of a prototype tricalcium silicate cement, which was mainly composed of synthetically prepared tricalcium silicate and zirconium oxide radiopacifier. The prototype tricalcium silicate cement, white ProRoot MTA (WMTA) and TheraCal LC (a light-cured resin-modified calcium silicate-filled material) were examined. The chemical compositions were analysed with a wavelength-dispersive X-ray spectroscopy electron probe microanalyser with an image observation function (SEM-EPMA). The pH and Ca 2+ concentrations of water in which the set materials had been immersed were measured, and the latter was assessed with the EDTA titration method. The surface precipitates formed on the materials immersed in phosphate-buffered saline (PBS) were analysed with SEM-EPMA and X-ray diffraction (XRD). Kruskal-Wallis tests followed by Mann-Whitney U-test with Bonferroni correction were used for statistical analysis (α = 0.05). The prototype cement contained Ca, Si and Zr as major elemental constituents, whereas it did not contain some metal elements that were detected in the other materials. The Ca 2+ concentrations and pH of the immersion water samples exhibited the following order: WMTA = prototype cement > TheraCal LC (P prototype cement and WMTA. The prototype tricalcium silicate cement exhibited similar Ca 2+ -releasing, alkalizing and apatite-like precipitate-forming abilities to WMTA. The Ca 2+ -releasing, alkalizing and apatite-like precipitate-forming abilities of TheraCal LC were lower than those of the other materials. © 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  18. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Barometric pressure sensor, Carbon dioxide (CO2) gas analyzer and other instruments from L'ASTROLABE in the Indian Ocean, South Pacific Ocean and others from 2002-10-16 to 2006-12-31 (NCEI Accession 0157276)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157276 includes Surface underway, chemical, meteorological and physical data collected from L'ASTROLABE in the Indian Ocean, South Pacific Ocean,...

  19. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, thermosalinographs and other instruments from JAMES CLARK ROSS in the South Atlantic Ocean and Southern Oceans from 2009-03-11 to 2009-04-17 (NCEI Accession 0157275)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157275 includes Surface underway, chemical and physical data collected from JAMES CLARK ROSS in the South Atlantic Ocean and Southern Oceans (> 60...

  20. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, thermosalinographs and other instruments from JAMES CLARK ROSS in the South Atlantic Ocean and Southern Oceans from 2008-01-02 to 2008-02-17 (NCEI Accession 0157284)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157284 includes Surface underway, chemical and physical data collected from JAMES CLARK ROSS in the South Atlantic Ocean and Southern Oceans (> 60...

  1. Partial pressure (or fugacity) of carbon dioxide and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from POLARSTERN in the North Atlantic Ocean, South Atlantic Ocean and others from 2016-02-20 to 2016-05-08 (NCEI Accession 0160572)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0160572 includes Surface underway, chemical and meteorological data collected from POLARSTERN in the North Atlantic Ocean, South Atlantic Ocean, South...

  2. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Barometric pressure sensor, Carbon dioxide (CO2) gas analyzer and other instruments from ROGER REVELLE in the South Pacific Ocean and Southern Oceans from 2005-01-06 to 2005-02-19 (NCEI Accession 0144243)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144243 includes Surface underway data collected from ROGER REVELLE in the South Pacific Ocean and Southern Oceans (> 60 degrees South) from...

  3. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from MIRAI in the Indian Ocean, Mozambique Channel and South Atlantic Ocean from 2003-12-09 to 2004-01-24 (NCEI Accession 0144250)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144250 includes Surface underway data collected from MIRAI in the Indian Ocean, Mozambique Channel and South Atlantic Ocean from 2003-12-09 to...

  4. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from POLARSTERN in the Arctic Ocean, North Atlantic Ocean and others from 2007-12-03 to 2008-08-05 (NCEI Accession 0157407)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157407 includes Surface underway, chemical, meteorological and physical data collected from POLARSTERN in the Arctic Ocean, North Atlantic Ocean,...

  5. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from ROGER REVELLE in the Indian Ocean and Southern Oceans from 2016-02-08 to 2016-03-15 (NCEI Accession 0157333)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157333 includes Surface underway, chemical, meteorological and physical data collected from ROGER REVELLE in the Indian Ocean and Southern Oceans...

  6. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from TANGAROA in the South Pacific Ocean, Southern Oceans and Tasman Sea from 2015-01-05 to 2015-12-23 (NCEI Accession 0157326)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157326 includes Surface underway, chemical, meteorological and physical data collected from TANGAROA in the South Pacific Ocean, Southern Oceans...

  7. Partial pressure (or fugacity) of carbon dioxide, temperature, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from TANGAROA in the Indian Ocean, South Pacific Ocean and others from 1999-02-02 to 1999-02-28 (NCEI Accession 0155958)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0155958 includes Surface underway, chemical, meteorological and physical data collected from TANGAROA in the Indian Ocean, South Pacific Ocean,...

  8. NOAA AVHRR Clear-Sky Products over Oceans (ACSPO): Sea Surface Temperature, Clear Sky Radiances, and Aerosol Optical Depth for the Global Ocean, 2011 - present (NCEI Accession 0072979)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The AVHRR Clear-Sky Processor over Oceans, jointly developed between NESDIS STAR and OSDPD, produces AVHRR clear-sky products over oceans. ACSPO generates output...

  9. Measurements of total dissolved inorganic carbon (DIC), total alkalinity (TA) and pH (on total scale) and other variables collected from surface underway observations using Dissolved Inorganic Carbon Extractor (DICE), Metrohm 876 Dosimat Plus, Agilent 8453 spectrometer and other instruments from R/V Roger Revelle in the Indian Ocean during the transit time on GO-SHIP sections I08S and I09N (EXPOCODEs 33RR20160208 and 33RR20160321) from 2016-02-08 to 2016-03-24 (NCEI Accession 0162262)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Ocean Ship-based Hydrographic Investigations Program (GO-SHIP) brings together scientists with interests in physical oceanography, the carbon cycle,...

  10. Extratropical Influence of Sea Surface Temperature and Wind on Water Recycling Rate Over Oceans and Coastal Lands

    Science.gov (United States)

    Hu, Hua; Liu, W. Timothy

    1999-01-01

    Water vapor and precipitation are two important parameters confining the hydrological cycle in the atmosphere and over the ocean surface. In the extratropical areas, due to variations of midlatitude storm tracks and subtropical jetstreams, water vapor and precipitation have large variability. Recently, a concept of water recycling rate defined previously by Chahine et al. (GEWEX NEWS, August, 1997) has drawn increasing attention. The recycling rate of moisture is calculated as the ratio of precipitation to total precipitable water (its inverse is the water residence time). In this paper, using multi-sensor spacebased measurements we will study the role of sea surface temperature and ocean surface wind in determining the water recycling rate over oceans and coastal lands. Response of water recycling rate in midlatitudes to the El Nino event will also be discussed. Sea surface temperature data are derived from satellite observations from the Advanced Very High Resolution Radiometer (AVHRR) blended with in situ measurements, available for the period 1982-1998. Global sea surface wind observations are obtained from spaceborne scatterometers aboard on the European Remote-Sensing Satellite (ERS1 and 2), available for the period 1991-1998. Global total precipitable water provided by the NASA Water Vapor Project (NVAP) is available for the period 1988-1995. Global monthly mean precipitation provided by the Global Precipitation Climatology Project (GPCP) is available for the period 1987-1998.

  11. Vibrational spectroscopic study of pH dependent solvation at a Ge(100)-water interface during an electrode potential triggered surface termination transition

    Science.gov (United States)

    Niu, Fang; Rabe, Martin; Nayak, Simantini; Erbe, Andreas

    2018-06-01

    The charge-dependent structure of interfacial water at the n-Ge(100)-aqueous perchlorate interface was studied by controlling the electrode potential. Specifically, a joint attenuated total reflection infrared spectroscopy and electrochemical experiment was used in 0.1M NaClO4 at pH ≈ 1-10. The germanium surface transformation to an H-terminated surface followed the thermodynamic Nernstian pH dependence and was observed throughout the entire pH range. A singular value decomposition-based spectra deconvolution technique coupled to a sigmoidal transition model for the potential dependence of the main components in the spectra shows the surface transformation to be a two-stage process. The first stage was observed together with the first appearance of Ge-H stretching modes in the spectra and is attributed to the formation of a mixed surface termination. This transition was reversible. The second stage occurs at potentials ≈0.1-0.3 V negative of the first one, shows a hysteresis in potential, and is attributed to the formation of a surface with maximum Ge-H coverage. During the surface transformation, the surface becomes hydrophobic, and an effective desolvation layer, a "hydrophobic gap," developed with a thickness ≈1-3 Å. The largest thickness was observed near neutral pH. Interfacial water IR spectra show a loss of strongly hydrogen-bound water molecules compared to bulk water after the surface transformation, and the appearance of "free," non-hydrogen bound OH groups, throughout the entire pH range. Near neutral pH at negative electrode potentials, large changes at wavenumbers below 1000 cm-1 were observed. Librational modes of water contribute to the observed changes, indicating large changes in the water structure.

  12. Migration of the guinea pig sperm membrane protein PH-20 from one localized surface domain to another does not occur by a simple diffusion-trapping mechanism.

    Science.gov (United States)

    Cowan, A E; Myles, D G; Koppel, D E

    1991-03-01

    The redistribution of membrane proteins on the surface of cells is a prevalent feature of differentiation in a variety of cells. In most cases the mechanism responsible for such redistribution is poorly understood. Two potential mechanisms for the redistribution of surface proteins are: (1) passive diffusion coupled with trapping, and (2) active translocation. We have studied the process of membrane protein redistribution for the PH-20 protein of guinea pig sperm, a surface protein required for sperm binding to the egg zona pellucida (P. Primakoff, H. Hyatt, and D. G. Myles (1985). J. Cell Biol. 101, 2239-2244). PH-20 protein is localized to the posterior head plasma menbrane of the mature sperm cell. Following the exocytotic acrosome reaction, PH-20 protein moves into the newly incorporated inner acrosomal membrane (IAM), placing it in a position favorable for a role in binding sperm to the egg zona pellucida (D. G. Myles, and P. Primakoff (1984), J. Cell Biol. 99, 1634-1641). To analyze the mechanistic basis for this protein migration, we have used fluorescence microscopy and digital image processing to characterize PH-20 protein migration in individual cells. PH-20 protein was observed to move against a concentration gradient in the posterior head plasma membrane. This result argues strongly against a model of passive diffusion followed by trapping in the IAM, and instead suggests that an active process serves to concentrate PH-20 protein toward the boundary separating the posterior head and IAM regions. A transient gradient of PH-20 concentration observed in the IAM suggests that once PH-20 protein reaches the IAM, it is freely diffusing. Additionally, we observed that migration of PH-20 protein was calcium dependent.

  13. Simulating ocean acidification and CO2 leakages from carbon capture and storage to assess the effects of pH reduction on cladoceran Moina mongolica Daday and its progeny.

    Science.gov (United States)

    Wang, Zaosheng; Wang, Youshao; Yan, Changzhou

    2016-07-01

    In order to evaluate the effects of pH reduction in seawater as a result of increasing levels of atmospheric CO2, laboratory-scale experiments simulating the scenarios of ocean acidification (OA) and CO2 leakages of carbon capture and storage (CCS) were performed using the model organism Moina mongolica Daday. The LpH50s calculated in cladoceran toxicity tests showed that M. mongolica exhibited intermediate sensitivity to OA, which varied among species and with ontogeny, when compared with different phyla or classes of marine biota. Survival, reproduction and fecundity of parthenogenetic females were evaluated after 21-day exposures. Results showed that increased acidity significantly reduced the rate of reproduction of M. mongolica resulting in a decreased intrinsic rate of natural increase (rm) across the gradients of pH reduction. The analysis of macromolecule contents in neonates suggested that nutritional status in progeny from all broods were significantly reduced as seawater pH decreased, with increasing magnitude in latter broods, except the contents of protein from two former broods and lipids from the first brood. Our findings clearly showed that for this ecologically and economically important fish species, the negative effects of pH reduction on both "quantity" and "quality" of progeny may have far-reaching implications, providing direct evidence that OA could influence the energetic transfer of marine food web and ecosystem functions in acidified oceans in the future. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Ocean Surface Topography Mission (OSTM) /Jason-3 Data Collection, 2015- (NCEI Accession 0118278)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — OSTM/JASON-3 is a follow-on mission continuing the TOPEX/Poseidon and Jason-1/2, and is designed to ensure continuity of high quality measurements for ocean science...

  15. Physico-chemical changes of ZnO nanoparticles with different size and surface chemistry under physiological pH conditions.

    Science.gov (United States)

    Gwak, Gyeong-Hyeon; Lee, Won-Jae; Paek, Seung-Min; Oh, Jae-Min

    2015-03-01

    We studied the physico-chemical properties of ZnO nanoparticles under physiological pH conditions (gastric, intestinal and plasma) as functions of their size (20 and 70 nm) and surface chemistry (pristine, L-serine, or citrate coating). ZnO nanoparticles were dispersed in phosphate buffered saline under physiological pH conditions and aliquots were collected at specific time points (0.5, 1, 4, 10 and 24 h) for further characterization. The pH values of the aqueous ZnO colloids at each condition were in the neutral to slightly basic range and showed different patterns depending on the original size and surface chemistry of the ZnO nanoparticles. The gastric pH condition was found to significantly dissolve ZnO nanoparticles up to 18-30 wt%, while the intestinal or plasma pH conditions resulted in much lower dissolution amounts than expected. Based on the X-ray diffraction patterns and X-ray absorption spectra, we identified partial phase transition of the ZnO nanoparticles from wurtzite to Zn(OH)2 under the intestinal and plasma pH conditions. Using scanning electron microscopy, we verified that the overall particle size and morphology of all ZnO nanoparticles were maintained regardless of the pH. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Synergistic effect of wire bending and salivary pH on surface properties and mechanical properties of orthodontic stainless steel archwires.

    Science.gov (United States)

    Hobbelink, Marieke G; He, Yan; Xu, Jia; Xie, Huixu; Stoll, Richard; Ye, Qingsong

    2015-01-01

    The aim of this study was to investigate the corrosive behaviour of stainless steel archwires in a more clinically relevant way by bending and exposing to various pH. One hundred and twenty pieces of rectangular stainless steel wires (0.43 × 0.64 mm) were randomly assigned into four groups. In each group, there were 15 pieces of bent wires and 15 straight ones. Prior to measurements of the wires, as individual experimental groups (group 1, 2, and 3), the wires were exposed to artificial saliva for 4 weeks at pH 5.6, 6.6, and 7.6, respectively. A control group of wires (group 4) remained in air for the same period of time before sent for measurements. Surface roughness (Ra-value) was measured by a profilometer. Young's modulus and maximum force were determined by a four-point flexural test apparatus. Scanning electron microscopy was used to observe the surface morphology of straight wire. Differences between groups were examined using a two-way analysis of variance (ANOVA). Mean surface roughness values, flexural Young's moduli, and maximum force values of bent wires are significantly different from those of the straight wires, which was the main effect of wire bending, ignoring the influence of pH. A significant effect was found between Ra-values regarding the main effect of pH, ignoring the influence of shape. There was a significant interaction effect of bending and pH on flexural Young's moduli of stainless steel archwires, while pH did not show much impact on the maximum force values of those stainless steel wires. Bigger surface irregularities were seen on SEM images of straight wires immersed in artificial saliva at pH 5.6 compared to artificial saliva at other pH values. Surface depth (Rz) was more sensitive than Ra in revealing surface roughness, both measured from 3D reconstructed SEM images. Ra showed a comparable result of surface roughness to Ra-value measured by the profilometer. Bending has a significant influence on surface roughness and mechanical

  17. Hydroxy-Al and cell-surface negativity are responsible for the enhanced sensitivity of Rhodotorula taiwanensis to aluminum by increased medium pH.

    Science.gov (United States)

    Zhao, Xue Qiang; Bao, Xue Min; Wang, Chao; Xiao, Zuo Yi; Hu, Zhen Min; Zheng, Chun Li; Shen, Ren Fang

    2017-10-01

    Aluminum (Al) is ubiquitous and toxic to microbes. High Al 3+ concentration and low pH are two key factors responsible for Al toxicity, but our present results contradict this idea. Here, an Al-tolerant yeast strain Rhodotorula taiwanensis RS1 was incubated in glucose media containing Al with a continuous pH gradient from pH 3.1-4.2. The cells became more sensitive to Al and accumulated more Al when pH increased. Calculations using an electrostatic model Speciation Gouy Chapman Stern indicated that, the increased Al sensitivity of cells was associated with AlOH 2+ and Al(OH) 2 + rather than Al 3+ . The alcian blue (a positively charged dye) adsorption and zeta potential determination of cell surface indicated that, higher pH than 3.1 increased the negative charge and Al adsorption at the cell surface. Taken together, the enhanced sensitivity of R. taiwanensis RS1 to Al from pH 3.1-4.2 was associated with increased hydroxy-Al and cell-surface negativity.

  18. The Impact of the Assimilation of Aquarius Sea Surface Salinity Data in the GEOS Ocean Data Assimilation System

    Science.gov (United States)

    Vernieres, Guillaume Rene Jean; Kovach, Robin M.; Keppenne, Christian L.; Akella, Santharam; Brucker, Ludovic; Dinnat, Emmanuel Phillippe

    2014-01-01

    Ocean salinity and temperature differences drive thermohaline circulations. These properties also play a key role in the ocean-atmosphere coupling. With the availability of L-band space-borne observations, it becomes possible to provide global scale sea surface salinity (SSS) distribution. This study analyzes globally the along-track (Level 2) Aquarius SSS retrievals obtained using both passive and active L-band observations. Aquarius alongtrack retrieved SSS are assimilated into the ocean data assimilation component of Version 5 of the Goddard Earth Observing System (GEOS-5) assimilation and forecast model. We present a methodology to correct the large biases and errors apparent in Version 2.0 of the Aquarius SSS retrieval algorithm and map the observed Aquarius SSS retrieval into the ocean models bulk salinity in the topmost layer. The impact of the assimilation of the corrected SSS on the salinity analysis is evaluated by comparisons with insitu salinity observations from Argo. The results show a significant reduction of the global biases and RMS of observations-minus-forecast differences at in-situ locations. The most striking results are found in the tropics and southern latitudes. Our results highlight the complementary role and problems that arise during the assimilation of salinity information from in-situ (Argo) and space-borne surface (SSS) observations

  19. Surface sulfonamide modification of poly(N-isopropylacrylamide)-based block copolymer micelles to alter pH and temperature responsive properties for controlled intracellular uptake.

    Science.gov (United States)

    Cyphert, Erika L; von Recum, Horst A; Yamato, Masayuki; Nakayama, Masamichi

    2018-06-01

    Two different surface sulfonamide-functionalized poly(N-isopropylacrylamide)-based polymeric micelles were designed as pH-/temperature-responsive vehicles. Both sulfadimethoxine- and sulfamethazine-surface functionalized micelles were characterized to determine physicochemical properties, hydrodynamic diameters, zeta potentials, temperature-dependent size changes, and lower critical solution temperatures (LCST) in both pH 7.4 and 6.8 solutions (simulating both physiological and mild low pH conditions), and tested in the incorporation of a proof-of-concept hydrophobic antiproliferative drug, paclitaxel. Cellular uptake studies were conducted using bovine carotid endothelial cells and fluorescently labeled micelles to evaluate if there was enhanced cellular uptake of the micelles in a low pH environment. Both variations of micelles showed enhanced intracellular uptake under mildly acidic (pH 6.8) conditions at temperatures slightly above their LCST and minimal uptake at physiological (pH 7.4) conditions. Due to the less negative zeta potential of the sulfamethazine-surface micelles compared to sulfadimethoxine-surface micelles, and the proximity of their LCST to physiological temperature (37°C), the sulfamethazine variation was deemed more amenable for clinically relevant temperature and pH-stimulated applications. Nevertheless, we believe both polymeric micelle variations have the capacity to be implemented as an intracellular drug or gene delivery system in response to mildly acidic conditions. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1552-1560, 2018. © 2018 Wiley Periodicals, Inc.

  20. Abrupt sea surface pH change at the end of the Younger Dryas in the central sub-equatorial Pacific inferred from boron isotope abundance in corals (Porites

    Directory of Open Access Journals (Sweden)

    A. Juillet-Leclerc

    2010-08-01

    Full Text Available The "δ11B-pH" technique was applied to modern and ancient corals Porites from the sub-equatorial Pacific areas (Tahiti and Marquesas spanning a time interval from 0 to 20.720 calendar years to determine the amplitude of pH changes between the Last Glacial Period and the Holocene. Boron isotopes were measured by Multi-Collector – Inductively Coupled Plasma Mass Spectrometry (MC-ICPMS with an external reproducibility of 0.25‰, allowing a precision of about ±0.03 pH-units for pH values between 8 and 8.3. The boron concentration [B] and isotopic composition of modern samples indicate that the temperature strongly controls the partition coefficient KD for different aragonite species. Modern coral δ11B values and the reconstructed sea surface pH values for different Pacific areas match the measured pH expressed on the seawater scale and confirm the calculation parameters that were previously determined by laboratory calibration exercises. Most ancient sea surface pH reconstructions near Marquesas are higher than modern values. These values range between 8.19 and 8.27 for the Holocene and reached 8.30 at the end of the last glacial period (20.7 kyr BP. At the end of the Younger Dryas (11.50±0.1 kyr BP, the central sub-equatorial Pacific experienced a dramatic drop of up to 0.2 pH-units from the average pH of 8.2 before and after this short event. Using the marine carbonate algorithms, we recalculated the aqueous pCO2 to be 440±25 ppmV at around 11.5 kyr BP for corals at Marquesas and ~500 ppmV near Tahiti where it was assumed that pCO2 in the atmosphere was 250 ppmV. Throughout the Holocene, the difference in pCO2 between the ocean and the atmosphere at Marquesas (ΔpCO2 indicates that the surface waters behave as a moderate CO2 sink or source (−53 to 20 ppmV during El Niño-like conditions. By contrast, during the last glacial/interglacial transition, this area was a marked source of CO2 (21 to 92 ppmV for the atmosphere, highlighting

  1. Iron dissolution from volcanic ash in low-pH atmospheric water: a key control on volcanic iron input to the surface ocean?

    Science.gov (United States)

    Maters, E.; Delmelle, P.; Ayris, P. M.; Opfergelt, S.

    2012-12-01

    A low concentration of dissolved iron (Fe) limits phytoplankton growth in approximately 30% of the ocean. The input of soluble Fe to these High-Nutrient Low-Chlorophyll (HNLC) regions has the potential to boost primary production and thereby enhance the drawdown of atmospheric carbon dioxide (CO2). Over geological timescales, volcanic activity may alter the flux of Fe to the surface ocean and so contribute to modulating atmospheric CO2 concentrations, ultimately impacting the global climate. Ocean Fe fertilisation has also recently been found to contribute to century-scale carbon sequestration via the export of biomass to the seafloor. Atmospherically deposited volcanic ash is now increasingly seen as an intermittent source of Fe to the surface ocean. Understanding the process of Fe release from ash in solution is key for assessing the potential for ash, particularly that produced by large but rare explosive eruptions or during sustained periods of intense volcanism, to fertilise the marine environment. Previous studies have measured the release of Fe from ash in near-neutral pH solution, but the influence of interaction between ash and acidic cloud- or rainwater during transport on Fe release is poorly understood. In this study, seven volcanic ash samples ranging from tephrite to rhyolite (49-74 wt.% SiO2) were leached in pH 1 H2SO4 in batch reactors for 336 h, at a 1:500 ash-to-solution ratio, to investigate Fe release under acidic conditions. Major element concentrations were measured by inductively coupled plasma- atomic emission spectroscopy (ICP-AES) across a time series of ash leachates. Changes in ash surface composition induced by contact with acid solution were assessed by X-ray photoelectron spectroscopy (XPS). The Fe2+/Fe3+ ratio in ash leachates was also determined for the first time, using the Ferrozine method. The ash samples released 42 to 411 μmol m-2 of Fe over 336 h of leaching. High initial Fe release rates (>1 μmol m-2 h-1) sustained for up

  2. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, Coulometer for DIC measurement and other instruments from MIRAI in the Indian Ocean, South Pacific Ocean and Southern Oceans from 2012-11-28 to 2013-01-04 (NCEI Accession 0143950)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0143950 includes discrete sample and profile data collected from MIRAI in the Indian Ocean, South Pacific Ocean and Southern Oceans (> 60 degrees...

  3. Environmental biogeography of near-surface phytoplankton in the southeast Pacific Ocean

    Science.gov (United States)

    Hardy, John; Hanneman, Andrew; Behrenfeldt, Michael; Horner, Rita

    1996-10-01

    Biogeographic interpretation of large-scale phytoplankton distribution patterns in relation to surface hydrography is essential to understanding pelagic food web dynamics and biogeochemical processes influencing global climate. We examined the abundance and biomass of phytoplankton in relation to physical and chemical parameters in the southeast Pacific Ocean. Samples were collected along longitude 110°W, between 10°N and 60°S during late austral summer. Patterns of taxa abundance and hydrographic variables were interpreted by principal components analysis. Five distinct phytohydrographic regions were identified: (i) a north equatorial region of moderate productivity dominated by small flagellates, low nitrate and low-to-moderate pCO 2; (ii) a south equatorial region characterized by high primary productivity dominated by diatoms, high nutrient levels, and relatively high pCO 2; (iii) a central gyre region characterized by low productivity dominated by small flagellates, low nitrate, and high pCO 2; (iv) a sub-Antarctic region with moderate productivity dominated by coccolithophores, moderate nitrate concentrations, and low pCO 2; and (v) an Antarctic region with high productivity dominated by diatoms, very high nitrate, and low pCO 2. Productivity and average phytoplankton cell size were positively correlated with nitrate concentration. Total phytoplankton abundance was negatively correlated with pCO 2, photosynthetically active radiation, and ultraviolet-B radiation. The interaction between phytoplankton carbon assimilation, atmospheric CO2, and the inhibitory effect of ultraviolet radiation could have implications for the global climate. These data suggest that the effects would be greatest at southern mid-latitudes (40-50°S) where present phytoplankton production and predicted future increases in UV-B are both relatively high.

  4. Estimating the Augmented Reflectance Ratio of the Ocean Surface When Whitecaps Appear

    Directory of Open Access Journals (Sweden)

    Zhantang Xu

    2015-10-01

    Full Text Available The presence of foam influences the accuracy of satellite-derived water-leaving radiance. A model has been developed to estimate the augmented reflectance ratio (A(λ,U due to differences in the fraction of whitecap coverage (w on the ocean surface. A(λ,U can be calculated from the product of w and ρ(λ,U, where ρ(λ,U is the augmented ratio of the reflectance of background water (Rb(λ caused by the presence of whitecaps. Our results showed that the average A(400~700,U in the visible region was approximately 1.3% at U = 9 m∙s−1, 2.2% at U = 10 m∙s−1, 4.4% at U = 12 m∙s−1, 7.4% at U = 14 m∙s−1, 19% at U = 19 m∙s−1 and 37.9% at U = 24 m∙s−1, making it is necessary to consider the augmented reflectance ratio for remote sensing applications. By estimating remote sensing augmented reflectance using A(λ,U, it was found that the result was in good agreement with previous studies conducted in other areas with U from 9 to 12 m∙s−1. Since Rb(λ is temporally and spatially variable, our model considered the variation of Rb(λ, whereas existing models have assumed that Rb(λ is constant. Therefore, the proposed model is more suitable for estimating the augmented reflectance ratio due to whitecaps.

  5. Local inertial oscillations in the surface ocean generated by time-varying winds

    Science.gov (United States)

    Chen, Shengli; Polton, Jeff A.; Hu, Jianyu; Xing, Jiuxing

    2015-12-01

    A new relationship is presented to give a review study on the evolution of inertial oscillations in the surface ocean locally generated by time-varying wind stress. The inertial oscillation is expressed as the superposition of a previous oscillation and a newly generated oscillation, which depends upon the time-varying wind stress. This relationship is employed to investigate some idealized wind change events. For a wind series varying temporally with different rates, the induced inertial oscillation is dominated by the wind with the greatest variation. The resonant wind, which rotates anti-cyclonically at the local inertial frequency with time, produces maximal amplitude of inertial oscillations, which grows monotonically. For the wind rotating at non-inertial frequencies, the responses vary periodically, with wind injecting inertial energy when it is in phase with the currents, but removing inertial energy when it is out of phase. The wind rotating anti-cyclonically with time is much more favorable to generate inertial oscillations than the cyclonic rotating wind. The wind with a frequency closer to the inertial frequency generates stronger inertial oscillations. For a diurnal wind, the induced inertial oscillation is dependent on latitude and is most significant at 30 °. This relationship is also applied to examine idealized moving cyclones. The inertial oscillation is much stronger on the right-hand side of the cyclone path than on the left-hand side (in the northern hemisphere). This is due to the wind being anti-cyclonic with time on the right-hand side, but cyclonic on the other side. The inertial oscillation varies with the cyclone translation speed. The optimal translation speed generating the greatest inertial oscillations is 2 m/s at the latitude of 10 ° and gradually increases to 6 m/s at the latitude of 30 °.

  6. A rapid method for creating qualitative images indicative of thick oil emulsion on the ocean's surface from imaging spectrometer data

    Science.gov (United States)

    Kokaly, Raymond F.; Hoefen, Todd M.; Livo, K. Eric; Swayze, Gregg A.; Leifer, Ira; McCubbin, Ian B.; Eastwood, Michael L.; Green, Robert O.; Lundeen, Sarah R.; Sarture, Charles M.; Steele, Denis; Ryan, Thomas; Bradley, Eliza S.; Roberts, Dar A.; ,

    2010-01-01

    This report describes a method to create color-composite images indicative of thick oil:water emulsions on the surface of clear, deep ocean water by using normalized difference ratios derived from remotely sensed data collected by an imaging spectrometer. The spectral bands used in the normalized difference ratios are located in wavelength regions where the spectra of thick oil:water emulsions on the ocean's surface have a distinct shape compared to clear water and clouds. In contrast to quantitative analyses, which require rigorous conversion to reflectance, the method described is easily computed and can be applied rapidly to radiance data or data that have been atmospherically corrected or ground-calibrated to reflectance. Examples are shown of the method applied to Airborne Visible/Infrared Imaging Spectrometer data collected May 17 and May 19, 2010, over the oil spill from the Deepwater Horizon offshore oil drilling platform in the Gulf of Mexico.

  7. Distribution and sources of polycyclic aromatic hydrocarbons in surface sediments from the Bering Sea and western Arctic Ocean.

    Science.gov (United States)

    Zhao, Mengwei; Wang, Weiguo; Liu, Yanguang; Dong, Linsen; Jiao, Liping; Hu, Limin; Fan, Dejiang

    2016-03-15

    To analyze the distribution and sources of polycyclic aromatic hydrocarbons (PAHs) and evaluate their potential ecological risks, the concentrations of 16 PAHs were measured in 43 surface sediment samples from the Bering Sea and western Arctic Ocean. Total PAH (tPAH) concentrations ranged from 36.95 to 150.21 ng/g (dry weight). In descending order, the surface sediment tPAH concentrations were as follows: Canada Basin>northern Chukchi Sea>Chukchi Basin>southern Chukchi Sea>Aleutian Basin>Makarov Basin>Bering Sea shelf. The Bering Sea and western Arctic Ocean mainly received PAHs of pyrogenic origin due to pollution caused by the incomplete combustion of fossil fuels. The concentrations of PAHs in the sediments of the study areas did not exceed effects range low (ERL) values. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Detecting the influence of ocean process on the moisture supply for India summer monsoon from Satellite Sea Surface Salinity

    Science.gov (United States)

    Tang, W.; Yueh, S. H.; Liu, W. T.; Fore, A.; Hayashi, A.

    2016-02-01

    A strong contrast in the onset of Indian summer monsoon was observed by independent satellites: average rain rate over India subcontinent (IS) in June was more than doubled in 2013 than 2012 (TRMM); also observed are larger area of wet soil (Aquarius) and high water storage (GRACE). The difference in IS rainfall was contributed to the moisture inputs through west coast of India, estimated from ocean wind (OSCAT2) and water vapor (TMI). This is an interesting testbed for studying the role of ocean on terrestrial water cycle, in particular the Indian monsoon, which has tremendous social-economical impact. What is the source of extra moisture in 2013 or deficit in 2012 for the monsoon onset? Is it possible to quantify the contribution of ocean process that maybe responsible for redistributing the freshwater in favor of the summer monsoon moisture supply? This study aims to identify the influence of ocean processes on the freshwater exchange between air-sea interfaces, using Aquarius sea surface salinity (SSS). We found two areas in Indian Ocean with high correlation between IS rain rate and Aquarius SSS: one area is in the Arabian Sea adjacent to IS, another area is a horizontal patch from 60°E to 100°E centered around 10°S. On the other hand, E-P (OAflux, TRMM) shows no similar correlation patterns with IS rain. Based on the governing equation of the salt budget in the upper ocean, we define the freshwater flux, F, from the oceanic branch of the water cycle, including contributions from salinity tendency, advection, and subsurface process. The tendency and advection terms are estimated using Aquarius SSS and OSCAR ocean current. We will present results of analyzing the spatial and temporal variability of F and evidence of and hypothesis on how the oceanic processes may enhance the moisture supply for summer Indian monsoon onset in 2013 comparing with 2012. The NASA Soil Moisture Active Passive (SMAP) has been producing the global soil moisture (SM) every 2-3 days

  9. Decadal prediction skill in the ocean with surface nudging in the IPSL-CM5A-LR climate model

    OpenAIRE

    Mignot , Juliette; García-Serrano , Javier; Swingedouw , Didier; Germe , Agathe; Nguyen , Sébastien; Ortega , Pablo; Guilyardi , Éric; Ray , Sulagna

    2016-01-01

    International audience; Two decadal prediction ensembles, based on the same climate model (IPSL-CM5A-LR) and the same surface nudging initialization strategy are analyzed and compared with a focus on upper-ocean variables in different regions of the globe. One ensemble consists of 3-member hindcasts launched every year since 1961 while the other ensemble benefits from 9 members but with start dates only every 5 years. Analysis includes anomaly correlation coefficients and root mean square err...

  10. NOAA Climate Data Record (CDR) of Ocean Near Surface Atmospheric Properties, Version 1 (Version Superseded)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Please note, this dataset has been superseded by a newer version (see below). Users should not use this version except in rare cases (e.g., when reproducing previous...

  11. Ocean Surface Topography Mission (OSTM) /Jason-2: Ancillary Files (NODC Accession 0044982)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains the data descriptions for the OSTM/Jason-2 Ancillary data files, which is served through the NOAA/NESDIS Comprehensive Large Array-data...

  12. Ocean Surface Topography Mission (OSTM) /Jason-2: Orbital Information (NODC Accession 0044985)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains the descriptions for the OSTM/Jason-2 orbital information, which is served through the NOAA/NESDIS Comprehensive Large Array-data Stewardship...

  13. A Smart Climatology of Evaporation Duct Height and Surface Radar Propagation in the Indian Ocean

    National Research Council Canada - National Science Library

    Twigg, Katherine L

    2007-01-01

    .... We have used existing, civilian, dynamically balanced reanalysis data, for 1970 to 2006, and a state-of-the-art ED model, to produce a spatially and temporally refined EDH climatology for the Indian Ocean (10) and nearby seas...

  14. Ocean Surface Topography Mission (OSTM) /Jason-2: Telemetry (NODC Accession 0044986)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains the data descriptions for the OSTM/Jason-2 Telemetry data, which is served through the NOAA/NESDIS Comprehensive Large Array-data Stewardship...

  15. Ocean Surface Topography Mission (OSTM) /Jason-2: Auxiliary Files (NODC Accession 0044983)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains the data descriptions for the OSTM/Jason-2 Auxiliary data files, which is served through the NOAA/NESDIS Comprehensive Large Array-data...

  16. Ocean Surface Topography Mission (OSTM) - Jason-2 and Jason-3: Data Documentation Records (NCEI Accession 0118276)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — OSTM/JASON-2 and Jason-3 (scheduled for launch in 2015) are follow-on missions continuing the TOPEX/Poseidon and Jason-1 missions, and are designed to ensure...

  17. Surface water iron supplies in the Southern Ocean sustained by deep winter mixing

    CSIR Research Space (South Africa)

    Tagliabue, A

    2014-04-01

    Full Text Available Low levels of iron limit primary productivity across much of the Southern Ocean. At the basin scale, most dissolved iron is supplied to surfacewaters from subsurface reservoirs, because land inputs are spatially limited. Deep mixing in winter...

  18. Surface freshwater from Bay of Bengal runoff and Indonesian throughflow in the tropical Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Sengupta, D.; Raj, B.; Shenoi, S.S.C.

    ]); monthly evaporation from the Southampton Oceanography Centre (SOC) data (Josey et al. [1998]), and monthly 2openbulletby 2openbulletsurface currents in the tropical Indian Ocean, based on 1985-2002 trajecto- ries of drogued WOCE drifters (Shenoi et al..., Deep-Sea Re- search II, 50, 2111?2127, 2003. Josey, S. A., E. C. Kent, and P. K. Taylor, The Southampton Oceanography Centre (SOC) Ocean - Atmosphere Heat, Mo- mentum and Freshwater Flux Atlas, Tech. Rep. 6, Southamp- ton Oceanography Centre, 1998...

  19. The features of chlorophyll concentration long-standing dynamics in the ocean surface layer (comparison of czcs and seawifs data)

    Science.gov (United States)

    Shevyrnogov, A.; Vysotskaya, G.

    To preserve biosphere and make its utilization expedient makes imperative to comprehend in depth long-standing dynamics of the primary production process on our planet. Variability of chlorophyll concentration in the ocean is one of the most important components of this process. However, hard access and large size of the water surface make its investigation labor-consuming. Besides, the dependence of primary production on high variability of hydrophysical phenomena in the ocean (fluctuations of currents, frontal zones, etc.) makes the location of points for measuring the chlorophyll concentration dynamics significant. In this work the long-standing changes in chlorophyll concentration in the surface layer of the ocean have been analyzed on the basis of the CZCS data for 7.5 years and the SeaWiFS data from 1997 to 2003. It was shown that the average chlorophyll concentration calculated at all investigated area is varied moderately. However when analyzing spatially local trends, it was detected that areas exist with stable rise and fall of chlorophyll concentration. Some interesting features of the long-standing dynamics of chlorophyll concentration several interesting features were found. There are the various directions of long-term trends (constant increase or decrease) that cannot be explained only by large-scale hydrological phenomena in the ocean (currents, upwellings etc.). The next feature is a difference between the trends revealed by using the CZCS data and the trends based on the SeaWiFS data. Thus, the obtained results allow the possibility of identification of the ocean biota role in the global biospheric gas exchange.

  20. Historical temperature, salinity, oxygen, pH, and meteorological data collected from Former Soviet Union platforms Lomonosov, Murmanets, and Akademik Shokalsky in 1933 - 1962 years from Arctic Ocean, Barents Sea, Bering Sea, Chukchi Sea, East Siberian Sea, Kara Sea, and Laptev Sea (NODC Accession 0108117)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Historical temperature, salinity, oxygen, pH, and meteorological data collected from Former Soviet Union platforms Lomonosov,Murmanets, and Akademik Shokalsky in...

  1. Dissolved inorganic carbon, total alkalinity, pH, nutrients and other variables collected from profile and discrete sample observations using CTD, Niskin bottle, and other instruments from NOAA Ship Gordon Gunter off the U.S. East Coast during the East Coast Ocean Acidification (GU-15-04 ECOA1) from 2015-06-20 to 2015-07-23 (NCEI Accession 0159428)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains dissolved inorganic carbon, total alkalinity, pH, nutrients and other variables collected from profile and discrete sample...

  2. 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

  3. The SURFEXv7.2 land and ocean surface platform for coupled or offline simulation of earth surface variables and fluxes

    Directory of Open Access Journals (Sweden)

    V. Masson

    2013-07-01

    Full Text Available SURFEX is a new externalized land and ocean surface platform that describes the surface fluxes and the evolution of four types of surfaces: nature, town, inland water and ocean. It is mostly based on pre-existing, well-validated scientific models that are continuously improved. The motivation for the building of SURFEX is to use strictly identical scientific models in a high range of applications in order to mutualise the research and development efforts. SURFEX can be run in offline mode (0-D or 2-D runs or in coupled mode (from mesoscale models to numerical weather prediction and climate models. An assimilation mode is included for numerical weather prediction and monitoring. In addition to momentum, heat and water fluxes, SURFEX is able to simulate fluxes of carbon dioxide, chemical species, continental aerosols, sea salt and snow particles. The main principles of the organisation of the surface are described first. Then, a survey is made of the scientific module (including the coupling strategy. Finally, the main applications of the code are summarised. The validation work undertaken shows that replacing the pre-existing surface models by SURFEX in these applications is usually associated with improved skill, as the numerous scientific developments contained in this community code are used to good advantage.

  4. The SURFEXv7.2 land and ocean surface platform for coupled or offline simulation of earth surface variables and fluxes

    Science.gov (United States)

    Masson, V.; Le Moigne, P.; Martin, E.; Faroux, S.; Alias, A.; Alkama, R.; Belamari, S.; Barbu, A.; Boone, A.; Bouyssel, F.; Brousseau, P.; Brun, E.; Calvet, J.-C.; Carrer, D.; Decharme, B.; Delire, C.; Donier, S.; Essaouini, K.; Gibelin, A.-L.; Giordani, H.; Habets, F.; Jidane, M.; Kerdraon, G.; Kourzeneva, E.; Lafaysse, M.; Lafont, S.; Lebeaupin Brossier, C.; Lemonsu, A.; Mahfouf, J.-F.; Marguinaud, P.; Mokhtari, M.; Morin, S.; Pigeon, G.; Salgado, R.; Seity, Y.; Taillefer, F.; Tanguy, G.; Tulet, P.; Vincendon, B.; Vionnet, V.; Voldoire, A.

    2013-07-01

    SURFEX is a new externalized land and ocean surface platform that describes the surface fluxes and the evolution of four types of surfaces: nature, town, inland water and ocean. It is mostly based on pre-existing, well-validated scientific models that are continuously improved. The motivation for the building of SURFEX is to use strictly identical scientific models in a high range of applications in order to mutualise the research and development efforts. SURFEX can be run in offline mode (0-D or 2-D runs) or in coupled mode (from mesoscale models to numerical weather prediction and climate models). An assimilation mode is included for numerical weather prediction and monitoring. In addition to momentum, heat and water fluxes, SURFEX is able to simulate fluxes of carbon dioxide, chemical species, continental aerosols, sea salt and snow particles. The main principles of the organisation of the surface are described first. Then, a survey is made of the scientific module (including the coupling strategy). Finally, the main applications of the code are summarised. The validation work undertaken shows that replacing the pre-existing surface models by SURFEX in these applications is usually associated with improved skill, as the numerous scientific developments contained in this community code are used to good advantage.

  5. Detection and variability of the Congo River plume from satellite derived sea surface temperature, salinity, ocean colour and sea level

    Science.gov (United States)

    Hopkins, Jo; Lucas, Marc; Dufau, Claire; Sutton, Marion; Lauret, Olivier

    2013-04-01

    The Congo River in Africa has the world's second highest annual mean daily freshwater discharge and is the second largest exporter of terrestrial organic carbon into the oceans. It annually discharges an average of 1,250 × 109 m3 of freshwater into the southeast Atlantic producing a vast fresh water plume, whose signature can be traced hundreds of kilometres from the river mouth. Large river plumes such as this play important roles in the ocean carbon cycle, often functioning as carbon sinks. An understanding of their extent and seasonality is therefore essential if they are to be realistically accounted for in global assessments of the carbon cycle. Despite its size, the variability and dynamics of the Congo plume are minimally documented. In this paper we analyse satellite derived sea surface temperature, salinity, ocean colour and sea level anomaly to describe and quantify the extent, strength and variability of the far-field plume and to explain its behaviour in relation to winds, ocean currents and fresh water discharge. Empirical Orthogonal Function analysis reveals strong seasonal and coastal upwelling signals, potential bimodal seasonality of the Angola Current and responses to fresh water discharge peaks in all data sets. The strongest plume-like signatures however were found in the salinity and ocean colour where the dominant sources of variability come from the Congo River itself, rather than from the wider atmosphere and ocean. These two data sets are then analysed using a statistically based water mass detection technique to isolate the behaviour of the plume. The Congo's close proximity to the equator means that the influence of the earth's rotation on the fresh water inflow is relatively small and the plume tends not to form a distinct coastal current. Instead, its behaviour is determined by wind and surface circulation patterns. The main axis of the plume between November and February, following peak river discharge, is oriented northwest, driven

  6. Global Ocean Surface Water Partial Pressure of CO2 Database: Measurements Performed During 1957-2016 (LDEO Database Version 2016) (NCEI Accession 0160492)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Approximately 10.8 million measurements of surface water pCO2 made over the global oceans during 1957-2016 have been processed to make a uniform data file in this...

  7. Linking sardine recruitment in coastal areas to ocean currents using surface drifters and HF radar. A case study in the Gulf of Manfredonia, Adriatic Sea

    DEFF Research Database (Denmark)

    Sciascia, Roberta; Berta, Maristella; Carlson, Daniel Frazier

    2017-01-01

    Understanding the role of ocean currents in the recruitment of commercially and ecologically important fish is an important step towards developing sustainable resource management guidelines. To this end, we attempt to elucidate the role of surface ocean transport in supplying recruits of sardine...

  8. Molecular dynamics simulation of the effect of pH on the adsorption of rhodamine laser dyes on TiO2 hydroxylated surfaces

    OpenAIRE

    2009-01-01

    Abstract We have carried out a study of the adsorption, on the (101) surface of anatase TiO2, of two industrially relevant rhodamines molecules (rhodamine 6G and rhodamine 800) employing Molecular Dynamics. These theoretical studies have shown that Rhodamine 6G must adsorb on surfaces under basic conditions. Moreover, the adsorption of this molecule shows a strong dependence upon the pH of the system, i.e. under neutral conditions the adsorption energy is quite smaller, and under ...

  9. Surface pH of fresh beef as a parameter to validate effectiveness of lactic acid treatment against E. coli O157:H7 and Salmonella

    Science.gov (United States)

    The beef industry must provide documentation to the regulatory agency that the antimicrobial interventions implemented or any subsequent change in the process is effective under the actual conditions that apply in its operation. The main objective of this study was to determine whether surface pH af...

  10. Electrostatic Assemblies of Well-Dispersed AgNPs on the Surface of Electrospun Nanofibers as Highly Active SERS Substrates for Wide-Range pH Sensing.

    Science.gov (United States)

    Yang, Tong; Ma, Jun; Zhen, Shu Jun; Huang, Cheng Zhi

    2016-06-15

    Surface-enhanced Raman scattering (SERS) has shown high promise in analysis and bioanalysis, wherein noble metal nanoparticles (NMNPs) such as silver nanoparticles were employed as substrates because of their strong localized surface plasmon resonance (LSPR) properties. However, SERS-based pH sensing was restricted because of the aggregation of NMNPs in acidic medium or biosamples with high ionic strength. Herein, by using the electrostatic interaction as a driving force, AgNPs are assembled on the surface of ethylene imine polymer (PEI)/poly(vinyl alcohol) (PVA) electrospun nanofibers, which are then applied as highly sensitive and reproducible SERS substrate with an enhancement factor (EF) of 10(7)-10(8). When p-aminothiophenol (p-ATP) is used as an indicator with its b2 mode, a good and wide linear response to pH ranging from 2.56 to 11.20 could be available, and the as-prepared nanocomposite fibers then could be fabricated as excellent pH sensors in complicated biological samples such as urine, considering that the pH of urine could reflect the acid-base status of a person. This work not only emerges a cost-effective, direct, and convenient approach to homogeneously decorate AgNPs on the surface of polymer nanofibers but also supplies a route for preparing other noble metal nanofibrous sensing membranes.

  11. The influence of artificial salivary pH on nickel ion release and the surface morphology of stainless steel bracket-nickel-titanium archwire combinations

    Directory of Open Access Journals (Sweden)

    Ida Bagus Narmada

    2017-06-01

    Full Text Available Background: In the oral cavity, orthodontic appliances come into contact with saliva which may cause corrosion capable of changing their surface morphology due to the release of metal ions. Surface roughness can influence the effectiveness of tooth movement. One of the ions possibly released when body fluid comes into contact with brackets and archwire is nickel ion (Ni. Ni, one of the most popular components of orthodontic appliances, is, however, a toxic element that could potentially increase the likelihood of health problems such as allergic responses during treatment. Purpose: The purpose of this study was to investigate the effect of different artificial salivary pH on the ions released and the surface morphology of stainless steel (SS brackets-nickel-titanium (NiTi and archwire combinations. Methods: Brackets and archwires were analyzed by an Energy Dispersive X-Ray Detector System (EDX to determine their composition, while NiTi archwire compound was examined by means of X-ray Diffraction (XRD. The immersion test was performed at artificial salivary pH levels of 4.2; 6.5; and 7.6 at 37°C for 28 days. Ni ion release measurement was performed using an Atomic Absorption Spectroscopy (AAS. Surface morphology was analyzed by means of a Scanning Electron Microscopy (SEM. Results: The chemical composition of all orthodontic appliances contained Ni element. In addition, XRD was depicted phases not only NiTi but also Ni, Titanium, Silicon and Zinc Oleate. The immersion test showed that the highest release of Ni ions occured at a pH of 4.2, with no significant difference at various levels of pH (p=.092. There were surface morphology changes in the orthodontic appliances. It was revealed that at a pH of 4.2, the surfaces of orthodontic appliances become unhomogenous and rough compared to those at other pH concentrations. Conclusion: The reduction of pH in the artificial saliva increases the amount of released Ni ions, as well as causing changes to

  12. Improvements to the swath-level near-surface atmospheric state parameter retrievals within the NRL Ocean Surface Flux System (NFLUX)

    Science.gov (United States)

    May, J. C.; Rowley, C. D.; Meyer, H.

    2017-12-01

    The Naval Research Laboratory (NRL) Ocean Surface Flux System (NFLUX) is an end-to-end data processing and assimilation system used to provide near-real-time satellite-based surface heat flux fields over the global ocean. The first component of NFLUX produces near-real-time swath-level estimates of surface state parameters and downwelling radiative fluxes. The focus here will be on the satellite swath-level state parameter retrievals, namely surface air temperature, surface specific humidity, and surface scalar wind speed over the ocean. Swath-level state parameter retrievals are produced from satellite sensor data records (SDRs) from four passive microwave sensors onboard 10 platforms: the Special Sensor Microwave Imager/Sounder (SSMIS) sensor onboard the DMSP F16, F17, and F18 platforms; the Advanced Microwave Sounding Unit-A (AMSU-A) sensor onboard the NOAA-15, NOAA-18, NOAA-19, Metop-A, and Metop-B platforms; the Advanced Technology Microwave Sounder (ATMS) sensor onboard the S-NPP platform; and the Advanced Microwave Scannin Radiometer 2 (AMSR2) sensor onboard the GCOM-W1 platform. The satellite SDRs are translated into state parameter estimates using multiple polynomial regression algorithms. The coefficients to the algorithms are obtained using a bootstrapping technique with all available brightness temperature channels for a given sensor, in addition to a SST field. For each retrieved parameter for each sensor-platform combination, unique algorithms are developed for ascending and descending orbits, as well as clear vs cloudy conditions. Each of the sensors produces surface air temperature and surface specific humidity retrievals. The SSMIS and AMSR2 sensors also produce surface scalar wind speed retrievals. Improvement is seen in the SSMIS retrievals when separate algorithms are used for the even and odd scans, with the odd scans performing better than the even scans. Currently, NFLUX treats all SSMIS scans as even scans. Additional improvement in all of

  13. Trichodesmium blooms and warm-core ocean surface features in the Arabian Sea and the Bay of Bengal.

    Science.gov (United States)

    Jyothibabu, R; Karnan, C; Jagadeesan, L; Arunpandi, N; Pandiarajan, R S; Muraleedharan, K R; Balachandran, K K

    2017-08-15

    Trichodesmium is a bloom-forming, diazotrophic, non-heterocystous cyanobacteria widely distributed in the warmer oceans, and their bloom is considered a 'biological indication' of stratification and nitrogen limitation in the ocean surface layer. In the first part of this paper, based on the retrospective analyses of the ocean surface mesoscale features associated with 59 Trichodesmium bloom incidences recorded in the past, 32 from the Arabian Sea and the Bay of Bengal, and 27 from the rest of the world, we have showed that warm-core features have an inducing effect on bloom formation. In the second part, we have considered the environmental preferences of Trichodesmium bloom based on laboratory and field studies across the globe, and proposed a view about how warm-core features could provide an inducing pre-requisite condition for the bloom formation in the Arabian Sea and the Bay of Bengal. Proposed that the subsurface waters of warm-core features maintain more likely chances for the conducive nutrient and light conditions required for the triggering of the blooms. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. The Potential and Challenges of Using Soil Moisture Active Passive (SMAP Sea Surface Salinity to Monitor Arctic Ocean Freshwater Changes

    Directory of Open Access Journals (Sweden)

    Wenqing Tang

    2018-06-01

    Full Text Available Sea surface salinity (SSS links various components of the Arctic freshwater system. SSS responds to freshwater inputs from river discharge, sea ice change, precipitation and evaporation, and oceanic transport through the open straits of the Pacific and Atlantic oceans. However, in situ SSS data in the Arctic Ocean are very sparse and insufficient to depict the large-scale variability to address the critical question of how climate variability and change affect the Arctic Ocean freshwater. The L-band microwave radiometer on board the NASA Soil Moisture Active Passive (SMAP mission has been providing SSS measurements since April 2015, at approximately 60 km resolution with Arctic Ocean coverage in 1–2 days. With improved land/ice correction, the SMAP SSS algorithm that was developed at the Jet Propulsion Laboratory (JPL is able to retrieve SSS in ice-free regions 35 km of the coast. SMAP observes a large-scale contrast in salinity between the Atlantic and Pacific sides of the Arctic Ocean, while retrievals within the Arctic Circle vary over time, depending on the sea ice coverage and river runoff. We assess the accuracy of SMAP SSS through comparative analysis with in situ salinity data collected by Argo floats, ships, gliders, and in field campaigns. Results derived from nearly 20,000 pairs of SMAP and in situ data North of 50°N collocated within a 12.5-km radius and daily time window indicate a Root Mean Square Difference (RMSD less than ~1 psu with a correlation coefficient of 0.82 and a near unity regression slope over the entire range of salinity. In contrast, the Hybrid Coordinate Ocean Model (HYCOM has a smaller RMSD with Argo. However, there are clear systematic biases in the HYCOM for salinity in the range of 25–30 psu, leading to a regression slope of about 0.5. In the region North of 65°N, the number of collocated samples drops more than 70%, resulting in an RMSD of about 1.2 psu. SMAP SSS in the Kara Sea shows a consistent

  15. Strong relationship between DMS and the solar radiation dose over the global surface ocean.

    Science.gov (United States)

    Vallina, Sergio M; Simó, Rafel

    2007-01-26

    Marine biogenic dimethylsulfide (DMS) is the main natural source of tropospheric sulfur, which may play a key role in cloud formation and albedo over the remote ocean. Through a global data analysis, we found that DMS concentrations are highly positively correlated with the solar radiation dose in the upper mixed layer of the open ocean, irrespective of latitude, plankton biomass, or temperature. This is a necessary condition for the feasibility of a negative feedback in which light-attenuating DMS emissions are in turn driven by the light dose received by the pelagic ecosystem.

  16. 3D Dynamics of the Near-Surface Layer of the Ocean in the Presence of Freshwater Influx

    Science.gov (United States)

    Dean, C.; Soloviev, A.

    2015-12-01

    Freshwater inflow due to convective rains or river runoff produces lenses of freshened water in the near surface layer of the ocean. These lenses are localized in space and typically involve both salinity and temperature anomalies. Due to significant density anomalies, strong pressure gradients develop, which result in lateral spreading of freshwater lenses in a form resembling gravity currents. Gravity currents inherently involve three-dimensional dynamics. The gravity current head can include the Kelvin-Helmholtz billows with vertical density inversions. In this work, we have conducted a series of numerical experiments using computational fluid dynamics tools. These numerical simulations were designed to elucidate the relationship between vertical mixing and horizontal advection of salinity under various environmental conditions and potential impact on the pollution transport including oil spills. The near-surface data from the field experiments in the Gulf of Mexico during the SCOPE experiment were available for validation of numerical simulations. In particular, we observed a freshwater layer within a few-meter depth range and, in some cases, a density inversion at the edge of the freshwater lens, which is consistent with the results of numerical simulations. In conclusion, we discuss applicability of these results to the interpretation of Aquarius and SMOS sea surface salinity satellite measurements. The results of this study indicate that 3D dynamics of the near-surface layer of the ocean are essential in the presence of freshwater inflow.

  17. Energy coupling of nuclear bursts in and above the ocean surface: source region calculations and experimental validation

    International Nuclear Information System (INIS)

    Clarke, D.B.; Harben, P.E.; Rock, D.W.; White, J.W.; Piacsek, A.

    1997-01-01

    In support of the Comprehensive Test Ban, research is under way on the long range propagation of signals from nuclear explosions in deep underwater sound (SOFAR) channel. Initially our work at LLNL on signals in the source region considered explosions in or above deep ocean. We studied the variation of wave properties and source region energy coupling as a function of height or depth of burst. Initial calculations on the CALE hydrodynamics code were linked at a few hundred milliseconds to a version of NRL's weak code, NPE, which solves the nonlinear progressive wave equation. The simulation of the wave propagation was carried down to 5000 m depth and out to 10,000 m range. We have completed ten such simulations at a variety of heights and depths below the ocean surface

  18. Big Jump of Record Warm Global Mean Surface Temperature in 2014-2016 Related to Unusually Large Oceanic Heat Releases

    Science.gov (United States)

    Yin, Jianjun; Overpeck, Jonathan; Peyser, Cheryl; Stouffer, Ronald

    2018-01-01

    A 0.24°C jump of record warm global mean surface temperature (GMST) over the past three consecutive record-breaking years (2014-2016) was highly unusual and largely a consequence of an El Niño that released unusually large amounts of ocean heat from the subsurface layer of the northwestern tropical Pacific. This heat had built up since the 1990s mainly due to greenhouse-gas (GHG) forcing and possible remote oceanic effects. Model simulations and projections suggest that the fundamental cause, and robust predictor of large record-breaking events of GMST in the 21st century, is GHG forcing rather than internal climate variability alone. Such events will increase in frequency, magnitude, and duration, as well as impact, in the future unless GHG forcing is reduced.

  19. Diagnostic model of 3-D circulation in the Arabian Sea and western equatorial Indian Ocean: Results of monthly mean sea surface topography

    Digital Repository Service at National Institute of Oceanography (India)

    Bahulayan, N.; Shaji, C.

    A three-dimensional diagnostic model has been developed to compute the monthly mean circulation and sea surface topography in the Western Tropical Indian Ocean north of 20 degrees S and west of 80 degrees E. The diagnostic model equations...

  20. MERRA 2D IAU Ocean Surface Diagnostic, Single Level, Time Avg 1-hr (2/3x1/2L1) V5.2.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The MAT1NXOCN or tavg1_2d_ocn_Nx data product is the MERRA Data Assimilation System 2-Dimensional ocean surface single-level diagnostics that is time averaged...

  1. MERRA 2D IAU Ocean Surface Diagnostic, Single Level, Monthly Mean (2/3x1/2L1) V5.2.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The MATMNXOCN or tavgM_2d_ocn_Nx data product is the MERRA Data Assimilation System 2-Dimensional ocean surface single-level diagnostics that is monthly mean...

  2. MERRA 2D IAU Ocean Surface Diagnostic, Single Level, Diurnal (2/3x1/2L1) V5.2.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The MATUNXOCN or tavgU_2d_ocn_Nx data product is the MERRA Data Assimilation System 2-Dimensional ocean surface single-level diagnostics that is monthly mean...

  3. A Novel Low-cost, Ka-band, High Altitude, Multi-Baseline Unmanned Aerial Vehicle Sensor for Surface Water Ocean Topography, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal presents the Ka-band SWOT Phenomenology Airborne Radar (KaSPAR) to support the surface water ocean topography (SWOT) mission for science and algorithm...

  4. Influence of statistical surface models on dynamic scattering of high-frequency signals from the ocean surface (A)

    DEFF Research Database (Denmark)

    Bjerrum-Niese, Christian; Jensen, Leif Bjørnø

    1994-01-01

    ; the surface roughness is described by a spatial surface spectrum and the surface motion is described by the gravity-wave dispersion relation [D. Dowling and D. Jackson, J. Acoust. Soc. Am. 93, 3149–3157 (1993)]. Applying some modifications to this approach, the temporal coherence function is found...

  5. Warm mid-Cretaceous high-latitude sea-surface temperatures from the southern Tethys Ocean and cool high-latitude sea-surface temperatures from the Arctic Ocean: asymmetric worldwide distribution of dinoflagellates

    Science.gov (United States)

    Masure, Edwige; Desmares, Delphine; Vrielynck, Bruno

    2014-05-01

    Dealing with 87 articles and using a Geographical Information System, Masure and Vrielynck (2009) have mapped worldwide biogeography of 38 Late Albian dinoflagellate cysts and have demonstrated Cretaceous oceanic bioclimatic belts. For comparison 30 Aptian species derived from 49 studies (Masure et al., 2013) and 49 Cenomanian species recorded from 33 articles have been encountered. Tropical, Subtropical, Boreal, Austral, bipolar and cosmopolitan species have been identified and Cretaceous dinoflagellate biomes are introduced. Asymmetric distribution of Aptian and Late Albian/Cenomanian subtropical Tethyan species, from 40°N to 70°S, demonstrates asymmetric Aptian and Late Albian/Cenomanian Sea Surface Temperature (SST) gradients with warm water masses in high latitudes of Southern Ocean. The SST gradients were stronger in the Northern Hemisphere than in the Southern Hemisphere. We note that Aptian and Late Albian/Cenomanian dinoflagellates restricted to subtropical and subpolar latitudes met and mixed at 35-40°N, while they mixed from 30°S to 70°S and from 50°S to 70°S respectively in the Southern Hemisphere. Mixing belts extend on 5° in the Northern Hemisphere and along 40° (Aptian) and 20° (Late Albian/Cenomanian) in the Southern one. The board southern mixing belt of Tethyan and Austral dinoflagellates suggest co-occurrence of warm and cold currents. We record climatic changes such as the Early Aptian cooler period and Late Aptian and Albian warming through the poleward migration of species constrained to cool water masses. These species sensitive to temperature migrated from 35°N to 55°N through the shallow Greenland-Norwergian Seaway connecting the Central Atlantic and the Arctic Ocean. While Tethyan species did not migrate staying at 40°N. We suggest that the Greenland-Norwergian Seaway might has been a barrier until Late Albian/Cenomanian for oceanic Tethyan dinoflagellates stopped either by the shallow water column or temperature and salinity

  6. Processes controlling the surface temperature signature of the Madden-Julian oscillation in the thermocline ridge of the Indian Ocean

    Energy Technology Data Exchange (ETDEWEB)

    Jayakumar, A.; Gnanaseelan, C. [Indian Institute of Tropical Meteorology, Pune (India); Vialard, Jerome; Lengaigne, M. [CNRS, UPMC, IRD, Case 100, Universite P. et M. Curie, Laboratoire d' Oceanographie Experimentation et Approches Numeriques, LOCEAN, Paris Cedex 05 (France); National Institute of Oceanography, Goa (India); McCreary, Julian P. [University of Hawaii, International Pacific Research Centre, Hawaii (United States); Praveen Kumar, B. [National Institute of Oceanography, Goa (India)

    2011-12-15

    During boreal winter, there is a prominent maximum of intraseasonal sea-surface temperature (SST) variability associated with the Madden-Julian Oscillation (MJO) along a Thermocline Ridge located in the southwestern Indian Ocean (5 S-10 S, 60 E-90 E; TRIO region). There is an ongoing debate about the relative importance of air-sea heat fluxes and oceanic processes in driving this intraseasonal SST variability. Furthermore, various studies have suggested that interannual variability of the oceanic structure in the TRIO region could modulate the amplitude of the MJO-driven SST response. In this study, we use observations and ocean general circulation model (OGCM) experiments to quantify these two effects over the 1997-2006 period. Observational analysis indicates that Ekman pumping does not contribute significantly (on average) to intraseasonal SST variability. It is, however, difficult to quantify the relative contribution of net heat fluxes and entrainment to SST intraseasonal variability from observations alone. We therefore use a suite of OGCM experiments to isolate the impacts of each process. During 1997-2006, wind stress contributed on average only about 20% of the intraseasonal SST variability (averaged over the TRIO region), while heat fluxes contributed about 70%, with forcing by shortwave radiation (75%) dominating the other flux components (25%). This estimate is consistent with an independent air-sea flux product, which indicates that shortwave radiation contributes 68% of intraseasonal heat flux variability. The time scale of the heat-flux perturbation, in addition to its amplitude, is also important in controlling the intraseasonal SST signature, with longer periods favouring a larger response. There are also strong year-to-year variations in the respective role of heat fluxes and wind stress. Of the five strong cooling events identified in both observations and the model (two in 1999 and one in 2000, 2001 and 2002), intraseasonal-wind stress dominates

  7. Surface distribution of dissolved trace metals in the oligotrophic ocean and their influence on phytoplankton biomass and productivity

    KAUST Repository

    Pinedo-González, Paulina

    2015-10-25

    The distribution of bioactive trace metals has the potential to enhance or limit primary productivity and carbon export in some regions of the world ocean. To study these connections, the concentrations of Cd, Co, Cu, Fe, Mo, Ni, and V were determined for 110 surface water samples collected during the Malaspina 2010 Circumnavigation Expedition (MCE). Total dissolved Cd, Co, Cu, Fe, Mo, Ni, and V concentrations averaged 19.0 ± 5.4 pM, 21.4 ± 12 pM, 0.91 ± 0.4 nM, 0.66 ± 0.3 nM, 88.8 ± 12 nM, 1.72 ± 0.4 nM, and 23.4 ± 4.4 nM, respectively, with the lowest values detected in the Central Pacific and increased values at the extremes of all transects near coastal zones. Trace metal concentrations measured in surface waters of the Atlantic Ocean during the MCE were compared to previously published data for the same region. The comparison revealed little temporal changes in the distribution of Cd, Co, Cu, Fe, and Ni over the last 30 years. We utilized a multivariable linear regression model to describe potential relationships between primary productivity and the hydrological, biological, trace nutrient and macronutrient data collected during the MCE. Our statistical analysis shows that primary productivity in the Indian Ocean is best described by chlorophyll a, NO3, Ni, temperature, SiO4, and Cd. In the Atlantic Ocean, primary productivity is correlated with chlorophyll a, NO3, PO4, mixed layer depth, Co, Fe, Cd, Cu, V, and Mo. The variables salinity, temperature, SiO4, NO3, PO4, Fe, Cd, and V were found to best predict primary productivity in the Pacific Ocean. These results suggest that some of the lesser studied trace elements (e.g., Ni, V, Mo, and Cd) may play a more important role in regulating oceanic primary productivity than previously thought and point to the need for future experiments to verify their potential biological functions.

  8. Surface distribution of dissolved trace metals in the oligotrophic ocean and their influence on phytoplankton biomass and productivity

    KAUST Repository

    Pinedo-Gonzá lez, Paulina; West, A. Joshua; Tovar-Sá nchez, Antonio; Duarte, Carlos M.; Marañ ó n, Emilio; Cermeñ o, Pedro; Gonzá lez, Natalia; Sobrino, Cristina; Huete-Ortega, Marí a; Ferná ndez, Ana; Ló pez-Sandoval, Daffne C.; Vidal, Montserrat; Blasco, Dolors; Estrada, Marta; Sañ udo-Wilhelmy, Sergio A.

    2015-01-01

    The distribution of bioactive trace metals has the potential to enhance or limit primary productivity and carbon export in some regions of the world ocean. To study these connections, the concentrations of Cd, Co, Cu, Fe, Mo, Ni, and V were determined for 110 surface water samples collected during the Malaspina 2010 Circumnavigation Expedition (MCE). Total dissolved Cd, Co, Cu, Fe, Mo, Ni, and V concentrations averaged 19.0 ± 5.4 pM, 21.4 ± 12 pM, 0.91 ± 0.4 nM, 0.66 ± 0.3 nM, 88.8 ± 12 nM, 1.72 ± 0.4 nM, and 23.4 ± 4.4 nM, respectively, with the lowest values detected in the Central Pacific and increased values at the extremes of all transects near coastal zones. Trace metal concentrations measured in surface waters of the Atlantic Ocean during the MCE were compared to previously published data for the same region. The comparison revealed little temporal changes in the distribution of Cd, Co, Cu, Fe, and Ni over the last 30 years. We utilized a multivariable linear regression model to describe potential relationships between primary productivity and the hydrological, biological, trace nutrient and macronutrient data collected during the MCE. Our statistical analysis shows that primary productivity in the Indian Ocean is best described by chlorophyll a, NO3, Ni, temperature, SiO4, and Cd. In the Atlantic Ocean, primary productivity is correlated with chlorophyll a, NO3, PO4, mixed layer depth, Co, Fe, Cd, Cu, V, and Mo. The variables salinity, temperature, SiO4, NO3, PO4, Fe, Cd, and V were found to best predict primary productivity in the Pacific Ocean. These results suggest that some of the lesser studied trace elements (e.g., Ni, V, Mo, and Cd) may play a more important role in regulating oceanic primary productivity than previously thought and point to the need for future experiments to verify their potential biological functions.

  9. Diazotroph Diversity in the Sea Ice, Melt Ponds, and Surface Waters of the Eurasian Basin of the Central Arctic Ocean.

    Science.gov (United States)

    Fernández-Méndez, Mar; Turk-Kubo, Kendra A; Buttigieg, Pier L; Rapp, Josephine Z; Krumpen, Thomas; Zehr, Jonathan P; Boetius, Antje

    2016-01-01

    The Eurasian basin of the Central Arctic Ocean is nitrogen limited, but little is known about the presence and role of nitrogen-fixing bacteria. Recent studies have indicated the occurrence of diazotrophs in Arctic coastal waters potentially of riverine origin. Here, we investigated the presence of diazotrophs in ice and surface waters of the Central Arctic Ocean in the summer of 2012. We identified diverse communities of putative diazotrophs through targeted analysis of the nifH gene, which encodes the iron protein of the nitrogenase enzyme. We amplified 529 nifH sequences from 26 samples of Arctic melt ponds, sea ice and surface waters. These sequences resolved into 43 clusters at 92% amino acid sequence identity, most of which were non-cyanobacterial phylotypes from sea ice and water samples. One cyanobacterial phylotype related to Nodularia sp. was retrieved from sea ice, suggesting that this important functional group is rare in the Central Arctic Ocean. The diazotrophic community in sea-ice environments appear distinct from other cold-adapted diazotrophic communities, such as those present in the coastal Canadian Arctic, the Arctic tundra and glacial Antarctic lakes. Molecular fingerprinting of nifH and the intergenic spacer region of the rRNA operon revealed differences between the communities from river-influenced Laptev Sea waters and those from ice-related environments pointing toward a marine origin for sea-ice diazotrophs. Our results provide the first record of diazotrophs in the Central Arctic and suggest that microbial nitrogen fixation may occur north of 77°N. To assess the significance of nitrogen fixation for the nitrogen budget of the Arctic Ocean and to identify the active nitrogen fixers, further biogeochemical and molecular biological studies are needed.

  10. Diazotroph diversity in the sea ice, melt ponds and surface waters of the Eurasian Basin of the Central Arctic Ocean

    Directory of Open Access Journals (Sweden)

    Mar Fernández-Méndez

    2016-11-01

    Full Text Available The Eurasian basin of the Central Arctic Ocean is nitrogen limited, but little is known about the presence and role of nitrogen-fixing bacteria. Recent studies have indicated the occurrence of diazotrophs in Arctic coastal waters potentially of riverine origin. Here, we investigated the presence of diazotrophs in ice and surface waters of the Central Arctic Ocean in the summer of 2012. We identified diverse communities of putative diazotrophs through targeted analysis of the nifH gene, which encodes the iron protein of the nitrogenase enzyme. We amplified 529 nifH sequences from 26 samples of Arctic melt ponds, sea ice and surface waters. These sequences resolved into 43 clusters at 92% amino acid sequence identity, most of which were non-cyanobacterial phylotypes from sea ice and water samples. One cyanobacterial phylotype related to Nodularia sp. was retrieved from sea ice, suggesting that this important functional group is rare in the Central Arctic Ocean. The diazotrophic community in sea-ice environments appear distinct from other cold-adapted diazotrophic communities, such as those present in the coastal Canadian Arctic, the Arctic tundra and glacial Antarctic lakes. Molecular fingerprinting of nifH and the intergenic spacer region of the rRNA operon revealed differences between the communities from river-influenced Laptev Sea waters and those from ice-related environments pointing towards a marine origin for sea-ice diazotrophs. Our results provide the first record of diazotrophs in the Central Arctic and suggest that microbial nitrogen fixation may occur north of 77ºN. To assess the significance of nitrogen fixation for the nitrogen budget of the Arctic Ocean and to identify the active nitrogen fixers, further biogeochemical and molecular biological studies are needed.

  11. Surface Ocean Radiocarbon Reservoir Ages From Land-Sea Tephra Correlation Constrains Deglacial Chronology and Ocean Circulation in the Southeast Bering Sea

    Science.gov (United States)

    Cook, M. S.; Miller, R.; White-Nockleby, C.; Chapman, A.; Mix, A. C.

    2017-12-01

    Radiocarbon estimates of the past ocean are valuable because unlike passive tracers, radiocarbon has the potential to trace both the distribution and rate of transport of water masses. Most studies using paired radiocarbon measurements on planktonic and benthic foraminifera assume that the surface reservoir age was constant at the preindustrial value, which if incorrect, can strongly bias radiocarbon reconstructions. The subarctic Pacific is ringed by volcanic arcs, and there is great potential to use tephrochronology as a stratigraphic tool in sediments from the last glacial and deglaciation, and assign calendar ages to the marine sediment without relying on calibrated planktonic radiocarbon ages. In this study, we use major and trace element analysis of volcanic glass to match tephras between radiocarbon-dated lake cores from Sanak Island in the eastern Aleutians to marine cores from Umnak Plateau in the southeast Bering Sea. There are numerous thin tephras preserved in laminated sediments from the Bolling-Allerod and early Holocene in marine cores from depths (1000-1500 m) within the modern oxygen minimum zone. We find that trace elements are crucial in distinguishing tephras from individual eruptions. Our preliminary radiocarbon measurements suggest that the benthic-atmosphere radiocarbon differences and marine surface reservoir ages in the Bolling-Allerod are similar to pre-industrial values, supporting previously published radiocarbon reconstructions from the region.

  12. CAROLS: A New Airborne L-Band Radiometer for Ocean Surface and Land Observations

    DEFF Research Database (Denmark)

    Zribi, Mehrez; Parde, Mickael; Boutin, Jacquline

    2011-01-01

    The "Cooperative Airborne Radiometer for Ocean and Land Studies" (CAROLS) L-Band radiometer was designed and built as a copy of the EMIRAD II radiometer constructed by the Technical University of Denmark team. It is a fully polarimetric and direct sampling correlation radiometer. It is installed ...

  13. Surface and subsurface geostrophic current variability in the Indian Ocean from altimetry

    Digital Repository Service at National Institute of Oceanography (India)

    Cadden, D.D.H.; Subrahmanyam, B.; Chambers, D.P.; Murty, V.S.N.

    the World Ocean Atlas 2005. The results of this method were validated with currents measured using Acoustic Doppler Current Profilers moored along the equator at 77 degrees E, 83 degrees E, and 93 degrees E. The measured and computed currents compared...

  14. Retrieval of sea surface velocities using sequential Ocean Colour Monitor (OCM) data

    Digital Repository Service at National Institute of Oceanography (India)

    Prasad, J.S.; Rajawat, A.S.; Pradhan, Y.; Chauhan, O.S.; Nayak, S.R.

    The Indian remote sensing satellite, IRS-P4 (Oceansat-I) launched on May 26th, 1999 carried two sensors on board, i.e., the Ocean Colour Monitor (OCM) and the Multi-frequency Scanning Microwave Radiometer (MSMR) dedicated for oceanographic research...

  15. Deep-Sea Bioluminescence Blooms after Dense Water Formation at the Ocean Surface

    NARCIS (Netherlands)

    Tamburini, C.; Canals, M.; de Madron, X.D.; Houpert, L.; Lefevre, D.; Martini, V.; D'Ortenzio, F.; Robert, A.; Testor, P.; Aguilar, J.A.; Al Samarai, I.; Albert, A.; Andre, M.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; Jesus, A.C.A.; Astraatmadja, T.L.; Aubert, J.J.; Baret, B.; Basa, S.; Bertin, V.; Biagi, S.; Bigi, A.; Bigongiari, C.; Bogazzi, C.; Bou-Cabo, M.; Bouhou, B.; Bouwhuis, M.C.; Brunner, J.; Busto, J.; Camarena, F.; Capone, A.; Carloganu, C.; Carminati, G.; Carr, J.; Cecchini, S.; Charif, Z.; Charvis, P.; Chiarusi, T.; Circella, M.; Coniglione, R.; Costantini, H.; Coyle, P.; Curtil, C.; Decowski, P.; Dekeyser, I.; Deschamps, A.; Donzaud, C.; Dornic, D.; Dorosti, H.Q.; Drouhin, D.; Eberl, T.; Emanuele, U.; Ernenwein, J.P.; Escoffier, S.; Fermani, P.; Ferri, M.; Flaminio, V.; Folger, F.; Fritsch, U.; Fuda, J.L.; Galata, S.; Gay, P.; Giacomelli, G.; Giordano, V.; Gomez-Gonzalez, J.P.; Graf, K.; Guillard, G.; Halladjian, G.; Hallewell, G.; van Haren, H.; Hartman, J.; Heijboer, A.J.; Hello, Y.; Hernandez-Rey, J.J.; Herold, B.; Hossl, J.; Hsu, C.C.; De Jong, M.; Kadler, M.; Kalekin, O.; Kappes, A.; Katz, U.; Kavatsyuk, O.; Kooijman, P.; Kopper, C.; Kouchner, A.; Kreykenbohm, I.; Kulikovskiy, V.; Lahmann, R.; Lamare, P.; Larosa, G.; Lattuada, D.; Lim, G.; Lo Presti, D.; Loehner, H.; Loucatos, S.; Mangano, S.; Marcelin, M.; Margiotta, A.; Martinez-Mora, J.A.; Meli, A.; Montaruli, T.; Moscoso, L.; Motz, H.; Neff, M.; Nezri, E.N.; Palioselitis, D.; Pavalas, G.E.; Payet, K.; Payre, P.; Petrovic, J.; Piattelli, P.; Picot-Clemente, N.; Popa, V.; Pradier, T.; Presani, E.; Racca, C.; Reed, C.; Riccobene, G.; Richardt, C.; Richter, R.; Riviere, C.; Roensch, K.; Rostovtsev, A.; Ruiz-Rivas, J.; Rujoiu, M.; Russo, V.G.; Salesa, F.; Sanchez-Losa, A.; Sapienza, P.; Schock, F.; Schuller, J.P.; Schussler, F.; Shanidze, R.; Simeone, F.; Spies, A.; Spurio, M.; Steijger, J.J.M.; Stolarczyk, T.; Taiuti, M.G.F.; Toscano, S.; Vallage, B.; Van Elewyck, V.; Vannoni, G.; Vecchi, M.; Vernin, P.; Wijnker, G.; Wilms, J.; de Wolf, E.; Yepes, H.; Zaborov, D.; Zornoza, J.D.; Zuniga, J.

    2013-01-01

    The deep ocean is the largest and least known ecosystem on Earth. It hosts numerous pelagic organisms, most of which are able to emit light. Here we present a unique data set consisting of a 2.5-year long record of light emission by deep-sea pelagic organisms, measured from December 2007 to June

  16. Size, surface texture, chemical composition and mineralogy interrelations in ferromanganese nodules of central Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Banakar, V.K; Pattan, J.N.; Jauhari, P.

    Fiftyseven ferromanganese nodules, classified into 3 size class (4,4-6 and 6-8 cm diam.), from the siliceous sediments of central Indian Ocean were analysed for transition metals and representative sample from each size class for mineralogy. Smaller...

  17. Climate change and ocean deoxygenation within intensified surface-driven upwelling circulations.

    Science.gov (United States)

    Bakun, Andrew

    2017-09-13

    Ocean deoxygenation often takes place in proximity to zones of intense upwelling. Associated concerns about amplified ocean deoxygenation arise from an arguable likelihood that coastal upwelling systems in the world's oceans may further intensify as anthropogenic climate change proceeds. Comparative examples discussed include the uniquely intense seasonal Somali Current upwelling, the massive upwelling that occurs quasi-continuously off Namibia and the recently appearing and now annually recurring 'dead zone' off the US State of Oregon. The evident 'transience' in causal dynamics off Oregon is somewhat mirrored in an interannual-scale intermittence in eruptions of anaerobically formed noxious gases off Namibia. A mechanistic scheme draws the three examples towards a common context in which, in addition to the obvious but politically problematic remedy of actually reducing 'greenhouse' gas emissions, the potentially manageable abundance of strongly swimming, finely gill raker-meshed small pelagic fish emerges as a plausible regulating factor.This article is part of the themed issue 'Ocean ventilation and deoxygenation in a warming world'. © 2017 The Author(s).

  18. Citrobacter amalonaticus phytase on the cell surface of Pichia pastoris exhibits high pH stability as a promising potential feed supplement.

    Science.gov (United States)

    Li, Cheng; Lin, Ying; Huang, Yuanyuan; Liu, Xiaoxiao; Liang, Shuli

    2014-01-01

    Phytase expressed and anchored on the cell surface of Pichia pastoris avoids the expensive and time-consuming steps of protein purification and separation. Furthermore, yeast cells with anchored phytase can be used as a whole-cell biocatalyst. In this study, the phytase gene of Citrobacter amalonaticus was fused with the Pichia pastoris glycosylphosphatidylinositol (GPI)-anchored glycoprotein homologue GCW61. Phytase exposed on the cell surface exhibits a high activity of 6413.5 U/g, with an optimal temperature of 60°C. In contrast to secreted phytase, which has an optimal pH of 5.0, phytase presented on the cell surface is characterized by an optimal pH of 3.0. Moreover, our data demonstrate that phytase anchored on the cell surface exhibits higher pH stability than its secreted counterpart. Interestingly, our in vitro digestion experiments demonstrate that phytase attached to the cell surface is a more efficient enzyme than secreted phytase.

  19. Mitigation of FOD and Corrosion Fatigue Damage in 17-4 PH Stainless Steel Compressor Blades With Surface Treatment

    National Research Council Canada - National Science Library

    Prevey, Paul S; Jayaraman, N; Ravindranath, Ravi

    2004-01-01

    ... the geometrical conditions of thick section and blade leading edges of compressor blades. The FOD tolerance and corrosion fatigue performance of 17-4PH prepared by low plasticity burnishing (LPB), shot peening (SP...

  20. Characterization of the Fermi surface of BEDT-TTF4[Hg2Cl6].PhCl by electronic band structure calculations

    International Nuclear Information System (INIS)

    Veiros, L.F.; Canadell, E.

    1994-01-01

    Tight-binding band structure calculations for the room temperature structure of BEDT-TTF 4 [Hg 2 Cl 6 ]-PhCl show the existence of closed electron and hole Fermi surfaces, in agreement with the 2D metallic conductivity of this salt. It is shown that these closed Fermi surfaces result from the hybridization of two hidden 1D Fermi surfaces. However, our study also shows that a transition associated with either a usual or a hidden nesting type mechanism is unlikely. This explains why this salt retains its metallic properties without any resistivity anomaly down to 1.3 K. Our study suggests that BEDT-TTF 4 [Hg 2 Cl 6 ]-PhCl is somewhat anisotropic 2D semimetal and should exhibit Shubnikov-de Haas oscillations corresponding to a cross-sectional area of approximately 13% of the first Brillouin zone. (orig.)

  1. Effect of surface chemistry, solution pH, and ionic strength on the removal of herbicides diuron and amitrole from water by an activated carbon fiber.

    Science.gov (United States)

    Fontecha-Cámara, M A; López-Ramón, M V; Alvarez-Merino, M A; Moreno-Castilla, C

    2007-01-30

    A study was conducted on the effects of carbon surface chemistry, solution pH, and ionic strength on the removal of diuron and amitrole from aqueous solutions by adsorption on an as-received and oxidized activated carbon fiber. Results obtained were explained by the surface characteristics of the adsorbents and the characteristics of the herbicide molecules. Under the experimental conditions used, diuron uptake was much higher than that of amitrole, despite its larger molecular dimensions, due to the lesser water solubility, greater hydrophobicity, and larger dipolar moment of diuron compared with amitrole. Uptake variations associated with differences in carbon surface oxidation, solution pH, and ionic strength were explained by corresponding changes in electrostatic, hydrophobic, and van der Waals interactions.

  2. Increasing surface enhanced Raman spectroscopy effect of RNA and DNA components by changing the pH of silver colloidal suspensions.

    Science.gov (United States)

    Primera-Pedrozo, Oliva M; Rodríguez, Gabriela Del Mar; Castellanos, Jorge; Felix-Rivera, Hilsamar; Resto, Oscar; Hernández-Rivera, Samuel P

    2012-02-15

    This work focused on establishing the parameters for enhancing the Raman signals of DNA and RNA constituents: nitrogenous bases, nucleosides and nucleotides, using metallic nanoparticles as surface enhanced Raman scattering substrates. Silver nanospheres were synthesized using sodium borohydride as a reducing agent and sodium citrate as a capping agent. The prepared nanoparticles had a surface plasmon band at ∼384nm and an average size of 12±3nm. The nanoparticles' surface charge was manipulated by changing the pH of the Ag colloidal suspensions in the range of 1-13. Low concentrations as 0.7μM were detected under the experimental conditions. The optimum pH values were: 7 for adenine, 9 for AMP, 5 for adenosine, 7 for dAMP and 11 for deoxyadenosine. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. PH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from JAMES CLARK ROSS in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2015-12-17 to 2016-01-13 (NCEI Accession 0157011)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157011 includes chemical, discrete sample, physical and profile data collected from JAMES CLARK ROSS in the South Atlantic Ocean, South Pacific Ocean...

  4. Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from NOAA Ship RONALD H. BROWN in the North Pacific Ocean, South Pacific Ocean and Southern Oceans from 2007-12-15 to 2008-02-23 (NODC Accession 0109903)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0109903 includes discrete sample and profile data collected from NOAA Ship RONALD H. BROWN in the North Pacific Ocean, South Pacific Ocean and...

  5. Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from NATHANIEL B. PALMER in the South Atlantic Ocean, South Pacific Ocean and Southern Oceans from 2011-02-19 to 2011-04-23 (NODC Accession 0109933)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0109933 includes discrete sample and profile data collected from NATHANIEL B. PALMER in the South Atlantic Ocean, South Pacific Ocean and Southern...

  6. Control of the microstructure and surface chemistry of graphene aerogels via pH and time manipulation by a hydrothermal method.

    Science.gov (United States)

    García-Bordejé, E; Víctor-Román, S; Sanahuja-Parejo, O; Benito, A M; Maser, W K

    2018-02-15

    Three-dimensional graphene aerogels of controlled pore size have emerged as an important platform for several applications such as energy storage or oil-water separation. The aerogels of reduced graphene oxide are mouldable and light weight, with a porosity up to 99.9%, consisting mainly of macropores. Graphene aerogel preparation by self-assembly in the liquid phase is a promising strategy due to its tunability and sustainability. For graphene aerogels prepared by a hydrothermal method, it is known that the pH value has an impact on their properties but it is unclear how pH affects the auto-assembly process leading to the final properties. We have monitored the time evolution of the chemical and morphological properties of aerogels as a function of the initial pH value. In the hydrothermal treatment process, the hydrogel is precipitated earlier and with lower oxygen content for basic pH values (∼13 wt% O) than for acidic pH values (∼20 wt% O). Moreover, ∼7 wt% of nitrogen is incorporated on the graphene nanosheets at basic pH generated by NH 3 addition. To our knowledge, there is no precedent showing that the pH value affects the microstructure of graphene nanosheets, which become more twisted and bent for the more intensive deoxygenation occurring at basic pH. The bent nanosheets attained at pH = 11 reduce the stacking by the basal planes and they connect via the borders, hence leading eventually to higher pore volumes. In contrast, the flatter graphene nanosheets attained under acidic pH entail more stacking and higher oxygen content after a long hydrothermal treatment. The gravimetric absorption capacity of non-polar solvents scales directly with the pore volume. The aerogels have proved to be highly selective, recyclable and robust for the absorption of nonpolar solvents in water. The control of the porous structure and surface chemistry by manipulation of pH and time will also pave the way for other applications such as supercapacitors or batteries.

  7. Ocean acidification impacts bacteria – phytoplankton coupling at low-nutrient conditions

    NARCIS (Netherlands)

    Hornick, T.; Bach, L.T.; Crawfurd, K.J.; Spilling, K.; Achterberg, E.P.; Woodhouse, J.N.; Schulz, K.G.; Brussaard, C.P.D.; Riebesell, U.; Grossart, H.-P.

    2017-01-01

    The oceans absorb about a quarter of the annuallyproduced anthropogenic atmospheric carbon dioxide(CO2/, resulting in a decrease in surface water pH, aprocess termed ocean acidification (OA). Surprisingly littleis known about how OA affects the physiology of heterotrophicbacteria or the coupling of

  8. Using coral Ba/Ca records to investigate seasonal to decadal scale biogeochemical cycling in the surface and intermediate ocean.

    Science.gov (United States)

    LaVigne, M.; Cobb, K. M.; DeLong, K. L.; Freiberger, M. M.; Grottoli, A. G.; Hill, T. M.; Miller, H. R.; Nurhati, I. S.; Richey, J. N.; Serrato Marks, G.; Sherrell, R. M.

    2016-12-01

    Dissolved barium (BaSW), a bio-intermediate element, is linked to several biogeochemical processes such as the cycling and export of nutrients, organic carbon (Corg), and barite in surface and intermediate oceans. Dynamic BaSW cycling has been demonstrated in the water column on short timescales (days-weeks) while sedimentary records have documented geologic-scale changes in barite preservation driven by export production. Our understanding of how seasonal-decadal scale climate variability impacts these biogeochemical processes currently lacks robust records. Ba/Ca calibrations in surface and deep sea corals suggest barium is incorporated via cationic substitution in both aragonite and calcite. Here we demonstrate the utility of Ba/Ca for reconstructing biogeochemical variability using examples of surface and deep sea coral records. Century-long deep sea coral records from the California Current System (bamboo corals: 900-1500m) record interannual variations in Ba/Ca, likely reflecting changes in barite formation via bacterial Corg respiration or barite saturation state. A surface Porites coral Ba/Ca record from Christmas Island (central equatorial Pacific: 1978-1995) shows maxima during low productivity El Niño warm periods, suggesting that variations in BaSW are driven by biological removal via direct cellular uptake or indirectly via barite precipitation with the decomposition of large phytoplankton blooms at this location. Similarly, a sixteen-year long Siderastera siderea surface coral record from Dry Tortugas, FL (Gulf of Mexico: 1991-2007) shows seasonal Ba/Ca cycles that align with annual chlorophyll and δ13C. Taken together, these records demonstrate the linkages among Corg, nutrient cycling and BaSW in the surface and intermediate ocean on seasonal to decadal timescales. Multi-proxy paleoceanographic reconstructions including Ba/Ca have the potential to elucidate the mechanisms linking past climate, productivity, nutrients, and BaSW cycling in the past.

  9. Recent summer precipitation trends in the Greater Horn of Africa and the emerging role of Indian Ocean sea surface temperature

    Energy Technology Data Exchange (ETDEWEB)

    Williams, A.P. [Los Alamos National Laboratory, Earth and Environmental Sciences Division, Los Alamos, NM (United States); University of California, Geography Department, Santa Barbara, CA (United States); Funk, Chris [University of California, Geography Department, Santa Barbara, CA (United States); U.S. Geological Survey, Earth Resources Observation and Science (EROS), Sioux Falls, SD (United States); Michaelsen, Joel [University of California, Geography Department, Santa Barbara, CA (United States); Rauscher, Sara A. [Los Alamos National Laboratory, Theoretical Division, Los Alamos, NM (United States); Robertson, Iain; Loader, Neil J. [Swansea University, Department of Geography, College of Science, Swansea (United Kingdom); Wils, Tommy H.G. [Rotterdam University, Department of Geography, Rotterdam (Netherlands); Koprowski, Marcin [Nicolaus Copernicus University, Laboratory of Dendrochronology, Institute of Ecology and Environment Protection, Torun (Poland); Eshetu, Zewdu [Ethiopian Institute of Agricultural Research, Forestry Research Centre, Addis Ababa (Ethiopia)

    2012-11-15

    We utilize a variety of climate datasets to examine impacts of two mechanisms on precipitation in the Greater Horn of Africa (GHA) during northern-hemisphere summer. First, surface-pressure gradients draw moist air toward the GHA from the tropical Atlantic Ocean and Congo Basin. Variability of the strength of these gradients strongly influences GHA precipitation totals and accounts for important phenomena such as the 1960s-1980s rainfall decline and devastating 1984 drought. Following the 1980s, precipitation variability became increasingly influenced by the southern tropical Indian Ocean (STIO) region. Within this region, increases in sea-surface temperature, evaporation, and precipitation are linked with increased exports of dry mid-tropospheric air from the STIO region toward the GHA. Convergence of dry air above the GHA reduces local convection and precipitation. It also produces a clockwise circulation response near the ground that reduces moisture transports from the Congo Basin. Because precipitation originating in the Congo Basin has a unique isotopic signature, records of moisture transports from the Congo Basin may be preserved in the isotopic composition of annual tree rings in the Ethiopian Highlands. A negative trend in tree-ring oxygen-18 during the past half century suggests a decline in the proportion of precipitation originating from the Congo Basin. This trend may not be part of a natural cycle that will soon rebound because climate models characterize Indian Ocean warming as a principal signature of greenhouse-gas induced climate change. We therefore expect surface warming in the STIO region to continue to negatively impact GHA precipitation during northern-hemisphere summer. (orig.)

  10. Contributions of greenhouse gas forcing and the Southern Annular Mode to historical Southern Ocean surface temperature trends

    OpenAIRE

    Kostov, Yavor; Ferreira, David; Marshall, John; Armour, Kyle

    2018-01-01

    We examine the 1979-2014 Southern Ocean (SO) sea surface temperature (SST) trends simulated in an ensemble of coupled general circulation models and evaluate possible causes of the models’ inability to reproduce the observed 1979-2014 SO cooling. For each model we estimate the response of SO SST to step changes in greenhouse gas (GHG) forcing and in the seasonal indices of the Southern Annular Mode (SAM). Using these step-response functions, we skillfully reconstruct the models’ 1979-2014 SO ...

  11. Radiation processing of organics and biological materials exposed to ocean world surface conditions.

    Science.gov (United States)

    Hand, K. P.; Carlson, R. W.

    2017-12-01

    Assessing the habitability of ocean worlds, such as Europa and Enceladus, motivates a search for endogenous carbon compounds that could be indicative of a habitable, or even inhabited, subsurface liquid water environment. We have examined the role of destruction and synthesis of organic compounds via 10 keV electron bombardment of ices generated under temperature and pressure conditions comparable to Europa and Enceladus. Short-chain organics and ammonia, in combination with water, were exposed to Mrad to Grad doses and observed to evolve to a `lost' carbon fraction (CO and CO2) and a `retained' carbon fraction (consisting of a highly refractory `ocean world tholin' populated by highly radiation resistant carbonyl, aldehyde, and nitrile components). The retained fraction is of key importance as this likely represents the observable fraction for future spacecraft investigations. We also irradiated microbial spores (B. pumilis) to approximately 2 Grad and have found persistence of biomolecule fractions derived from proteins and nucleic acids.

  12. Influence of the sea surface temperature anomaly over the Indian Ocean in March on the summer rainfall in Xinjiang

    Science.gov (United States)

    Zhou, Yang; Huang, Anning; Zhao, Yong; Yang, Qing; Jiang, Jing; La, Mengke

    2015-02-01

    This study explores the relationship between the sea surface temperature over the Indian Ocean (IOSST) in March and the summer rainfall in Xinjiang. In the observations, the IOSST in March significantly correlates with the summer rainfall in Xinjiang with a correlation coefficient of about 0.49 during 1961-2007. This relationship is independent from the El Niño Southern Oscillation (ENSO), with a partial correlation coefficient of about 0.40-0.48 controlling for the ENSO indices from December to March. In addition to the observations, three sets of numerical sensitivity experiments are conducted with a regional climate model (RegCM4.3). The model results show that warm IOSST can excite a negative anomaly of geopotential height at 500 hPa over the Indian Ocean in March. This anomaly stays over the tropical Indian Ocean, and then propagates north to central Asia in June. Consequently, the anomalous wind associated with this geopotential height anomaly transports moisture from the Persian Gulf and the coast of Iran to Xinjiang, passing over Pakistan and the Tibetan Plateau. Therefore, the warm (cold) IOSST in March tends to cause the increase (decrease) of the summer rainfall over Xinjiang, especially in the Tian Shan and Kunlun Mountains.

  13. Bomb-test 90Sr in Pacific and Indian Ocean surface water as recorded by banded corals

    International Nuclear Information System (INIS)

    Toggweiler, J.R.; Trumbore, S.

    1985-01-01

    We report here measurements of bomb-test 90 Sr activity in the CaCO 3 skeletons of banded head forming corals collected from nine locations in the tropical Pacific and Indian Oceans. Density variations in skeletal carbonate demarcate annual growth bands and allow one to section individual years. Measurements of 90 Sr activity in the annual bands reconstruct the activity of the water in which the coral grew. Our oldest records date to the early years of the nuclear era and record not only fallout deposition from the major U.S. and Soviet tests of 1958-1962, but also the huge, and largely unappreciated, localized inputs from the U.S. tests at Eniwetok and Bikini atolls during 1952-1958. In the 1960's the 90 Sr activity in Indian Ocean surface water was twice as high as activity levels in the South Pacific at comparable latitudes. We suggest that substantial amounts of northern hemisphere fallout moved west and south into the Indian Ocean via passages through the Indonesian archipelago. Equatorial Pacific 90 Sr levels have remained relatively constant from the mid 1960's through the end of 1970's in spite of 90 Sr decay, reflecting a large-scale transfer of water between the temperate and tropical North Pacific. Activity levels at Fanning Is. (4 0 N, 160 0 W) appear to vary in conjunction with the 3-4 year El Nino cycle. (orig.)

  14. Spatial variations of prokaryotic communities in surface water from India Ocean to Chinese marginal seas and their underlining environmental determinants

    Directory of Open Access Journals (Sweden)

    Xiaowei eZheng

    2016-02-01

    Full Text Available To illustrate the biogeographic patterns of prokaryotic communities in surface sea water, 24 samples were systematically collected across a large distance from Indian Ocean to Chinese marginal seas, with an average distance of 453 km between two adjacent stations. A total of 841,364 quality reads was produced by the high throughput DNA sequencing of the 16S rRNA genes. Phylogenetic analysis showed that Proteobacteria were predominant in all samples, with Alphaproteobacteria and Gammaproteobacteria being the two most abundant components. Cyanobacteria represented the second largest fraction of the total quality reads, and mainly included Prochlorococcus and Synechococcus. The semi-closed marginal seas, including South China Sea (SCS and nearby regions, exhibited a transition in community composition between oceanic and coastal seas, based on the distribution patterns of Prochlorococcus and Synechococcus as well as a non-metric multidimensional scaling (NMDS analysis. Distinct clusters of prokaryotes from coastal and open seas, and from different water masses in Indian Ocean were obtained by Bray-Curtis dissimilarity analysis at the OTU level, revealing a clear spatial heterogeneity. The major environmental factors correlated with the community variation in this broad scale were identified as salinity, temperature and geographic distance. Community comparison among regions shows that anthropogenic contamination is another dominant factor in shaping the biogeographic patterns of the microorganisms. These results suggest that environmental factors involved in complex interactions between land and sea act synergistically in driving spatial variations in coastal areas.

  15. Potential of Future Hurricane Imaging Radiometer (HIRAD) Ocean Surface Wind Observations for Determining Tropical Storm Vortex Intensity and Structure

    Science.gov (United States)

    Atlas, Robert; Bailey, M. C.; Black, Peter; James, Mark; Johnson, James; Jones, Linwood; Miller, Timothy; Ruf, Christopher; Uhlhorn, Eric

    2008-01-01

    The Hurricane Imaging Radiometer (HIRAD) is an innovative technology development, which offers the potential of new and unique remotely sensed observations of both extreme oceanic wind events and strong precipitation from either UAS or satellite platforms. It is based on the airborne Stepped Frequency Microwave Radiometer (SFMR), which is a proven aircraft remote sensing technique for observing tropical cyclone ocean surface wind speeds and rain rates, including those of major hurricane intensity. The proposed HIRAD instrument advances beyond the current nadir viewing SFMR to an equivalent wide-swath SFMR imager using passive microwave synthetic thinned aperture radiometer technology. This sensor will operate over 4-7 GHz (C-band frequencies) where the required tropical cyclone remote sensing physics has been validated by both SFMR and WindSat radiometers. HIRAD incorporates a unique, technologically advanced array antenna and several other technologies successfully demonstrated by the NASA's Instrument Incubator Program. A brassboard version of the instrument is complete and has been successfully tested in an anechoic chamber, and development of the aircraft instrument is well underway. HIRAD will be a compact, lightweight, low-power instrument with no moving parts that will produce wide-swath imagery of ocean vector winds and rain during hurricane conditions when existing microwave sensors (radiometers or scatterometers) are hindered. Preliminary studies show that HIRAD will have a significant positive impact on analyses as either a new aircraft or satellite sensor.

  16. Variation with age of anisotropy under oceans, from great circle surface waves

    International Nuclear Information System (INIS)

    Journet, B.; Jobert, N.

    1982-01-01

    Global great circle measurements of regionalized mantle Love wave phase velocities are interpreted in terms of regional models. The same study had been made by J. J. Leveque (1980) for Rayleigh waves, and the resulting models for the two oceanic regions of different ages are used as a basis for comparison: the observed Love wave dispersion cannot be explained with these models if isotropic. The models obtained by inversion of Love wave data are compared with the models mentioned; the discrepancy appearing in the 250 km depth range between the velocities β/sub H/ and β/sub V/ of respectively SH and SV waves is indicative of polarization anisotropy. Moreover, we put forward a significant variation from young to old oceans: the difference between β/sub H/, and β/sub V/ is of the order of 1% for the former, compared to 3% for the latter. This variation can bring information about the behaviour of upper mantle materials in connection with the motion of oceanic plates

  17. Processes of 30-90 days sea surface temperature variability in the northern Indian Ocean during boreal summer

    Energy Technology Data Exchange (ETDEWEB)

    Vialard, J. [Univerite P. et M. Curie, Laboratoire d' Oceanographie Experimentation et Approches Numeriques (LOCEAN), Case 100, CNRS, IRD, Paris Cedex 05 (France); Jayakumar, A.; Gnanaseelan, C.; Goswami, B.N. [Indian Institute of Tropical Meteorology, Pune (India); Lengaigne, M. [Univerite P. et M. Curie, Laboratoire d' Oceanographie Experimentation et Approches Numeriques (LOCEAN), Case 100, CNRS, IRD, Paris Cedex 05 (France); CSIR, National Institute of Oceanography, Goa (India); Sengupta, D. [Indian Institute of Sciences, Centre of Atmospheric and Oceanic Sciences, Bangalore (India)

    2012-05-15

    During summer, the northern Indian Ocean exhibits significant atmospheric intraseasonal variability associated with active and break phases of the monsoon in the 30-90 days band. In this paper, we investigate mechanisms of the Sea Surface Temperature (SST) signature of this atmospheric variability, using a combination of observational datasets and Ocean General Circulation Model sensitivity experiments. In addition to the previously-reported intraseasonal SST signature in the Bay of Bengal, observations show clear SST signals in the Arabian Sea related to the active/break cycle of the monsoon. As the atmospheric intraseasonal oscillation moves northward, SST variations appear first at the southern tip of India (day 0), then in the Somali upwelling region (day 10), northern Bay of Bengal (day 19) and finally in the Oman upwelling region (day 23). The Bay of Bengal and Oman signals are most clearly associated with the monsoon active/break index, whereas the relationship with signals near Somali upwelling and the southern tip of India is weaker. In agreement with previous studies, we find that heat flux variations drive most of the intraseasonal SST variability in the Bay of Bengal, both in our model (regression coefficient, 0.9, against {proportional_to}0.25 for wind stress) and in observations (0.8 regression coefficient); {proportional_to}60% of the heat flux variation is due do shortwave radiation and {proportional_to}40% due to latent heat flux. On the other hand, both observations and model results indicate a prominent role of dynamical oceanic processes in the Arabian Sea. Wind-stress variations force about 70-100% of SST intraseasonal variations in the Arabian Sea, through modulation of oceanic processes (entrainment, mixing, Ekman pumping, lateral advection). Our {proportional_to}100 km resolution model suggests that internal oceanic variability (i.e. eddies) contributes substantially to intraseasonal variability at small-scale in the Somali upwelling region

  18. Processes of 30-90 days sea surface temperature variability in the northern Indian Ocean during boreal summer

    Science.gov (United States)

    Vialard, J.; Jayakumar, A.; Gnanaseelan, C.; Lengaigne, M.; Sengupta, D.; Goswami, B. N.

    2012-05-01

    During summer, the northern Indian Ocean exhibits significant atmospheric intraseasonal variability associated with active and break phases of the monsoon in the 30-90 days band. In this paper, we investigate mechanisms of the Sea Surface Temperature (SST) signature of this atmospheric variability, using a combination of observational datasets and Ocean General Circulation Model sensitivity experiments. In additio