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Sample records for air temperature sea

  1. Antarctic Sea ice variations and seasonal air temperature relationships

    NASA Technical Reports Server (NTRS)

    Weatherly, John W.; Walsh, John E.; Zwally, H. J.

    1991-01-01

    Data through 1987 are used to determine the regional and seasonal dependencies of recent trends of Antarctic temperature and sea ice. Lead-lag relationships involving regional sea ice and air temperature are systematically evaluated, with an eye toward the ice-temperature feedbacks that may influence climatic change. Over the 1958-1087 period the temperature trends are positive in all seasons. For the 15 years (l973-l987) for which ice data are available, the trends are predominantly positive only in winter and summer, and are most strongly positive over the Antarctic Peninsula. The spatially aggregated trend of temperature for this latter period is small but positive, while the corresponding trend of ice coverage is small but negative. Lag correlations between seasonal anomalies of the two variables are generally stronger with ice lagging the summer temperatures and with ice leading the winter temperatures. The implication is that summer temperatures predispose the near-surface waters to above-or below-normal ice coverage in the following fall and winter.

  2. Sea surface temperature anomalies, planetary waves, and air-sea feedback in the middle latitudes

    NASA Technical Reports Server (NTRS)

    Frankignoul, C.

    1985-01-01

    Current analytical models for large-scale air-sea interactions in the middle latitudes are reviewed in terms of known sea-surface temperature (SST) anomalies. The scales and strength of different atmospheric forcing mechanisms are discussed, along with the damping and feedback processes controlling the evolution of the SST. Difficulties with effective SST modeling are described in terms of the techniques and results of case studies, numerical simulations of mixed-layer variability and statistical modeling. The relationship between SST and diabatic heating anomalies is considered and a linear model is developed for the response of the stationary atmosphere to the air-sea feedback. The results obtained with linear wave models are compared with the linear model results. Finally, sample data are presented from experiments with general circulation models into which specific SST anomaly data for the middle latitudes were introduced.

  3. Robust comparison of climate models with observations using blended land air and ocean sea surface temperatures

    NASA Astrophysics Data System (ADS)

    Cowtan, Kevin; Hausfather, Zeke; Hawkins, Ed; Jacobs, Peter; Mann, Michael E.; Miller, Sonya K.; Steinman, Byron A.; Stolpe, Martin B.; Way, Robert G.

    2015-08-01

    The level of agreement between climate model simulations and observed surface temperature change is a topic of scientific and policy concern. While the Earth system continues to accumulate energy due to anthropogenic and other radiative forcings, estimates of recent surface temperature evolution fall at the lower end of climate model projections. Global mean temperatures from climate model simulations are typically calculated using surface air temperatures, while the corresponding observations are based on a blend of air and sea surface temperatures. This work quantifies a systematic bias in model-observation comparisons arising from differential warming rates between sea surface temperatures and surface air temperatures over oceans. A further bias arises from the treatment of temperatures in regions where the sea ice boundary has changed. Applying the methodology of the HadCRUT4 record to climate model temperature fields accounts for 38% of the discrepancy in trend between models and observations over the period 1975-2014.

  4. Robust Comparison of Climate Models with Observations Using Blended Land Air and Ocean Sea Surface Temperatures

    NASA Astrophysics Data System (ADS)

    Hausfather, Z.; Jacobs, P.; Cowtan, K.; Hawkins, E.; Mann, M. E.; Miller, S. K.; Steinman, B. A.; Way, R. G.; Stolpe, M.

    2015-12-01

    Model-observation comparisons provide an important test of climate models' ability to realistically simulate the transient evolution of the system. A great deal of attention has recently focused on the so-called "hiatus" period of the past ~15 years, when estimates of recent surface temperature evolution fall at the lower end of climate model projections. This work quantifies a systematic bias in model-observation comparisons arising from differential warming rates between sea surface temperatures and surface air temperatures over oceans. Global mean temperatures from climate model simulations are typically calculated using surface air temperatures, while the corresponding observations are based on a blend of air and sea surface temperatures. A further bias arises from the treatment of temperatures in regions where the sea ice boundary has changed. We discuss the magnitude of these biases, and their implications for the evaluation of climate model performance over the "hiatus" period and the full instrumental record.

  5. GSOD Based Daily Global Mean Surface Temperature and Mean Sea Level Air Pressure (1982-2011)

    SciTech Connect

    Xuan Shi, Dali Wang

    2014-05-05

    This data product contains all the gridded data set at 1/4 degree resolution in ASCII format. Both mean temperature and mean sea level air pressure data are available. It also contains the GSOD data (1982-2011) from NOAA site, contains station number, location, temperature and pressures (sea level and station level). The data package also contains information related to the data processing methods

  6. Combined land/sea surface-air-temperature trends, 1949-1972

    SciTech Connect

    Chen, R.S.

    1982-04-01

    A major deficiency in most previous studies of fluctuations in the earth's climate based on air temperature records has been the dearth of data from oceanic areas and the Southern Hemisphere. This study analyzes a unique collection of ship-based observations of surface air temperature assembled by the UK Meteorological Office in parallel with the station-based dataset developed by the National Center for Atmospheric Research from the publications World Weather Records and Monthly Climatic Data for the World. Based on this much more geographically comprehensive database, it is concluded that, during the 24-year period 1949 to 1972, no statistically significant warming or cooling trends were evident in the time series of globally averaged surface air temperature measurements. However, temperature trends did vary latitudinally, with significant cooling in northern extra-tropical latitudes, no trend in equatorial latitudes, and significant but not homogeneous warming in southern extra-tropical latitudes. Time series of air temperatures over land and sea exhibited qualitatively similar behavior over the period 1949 to 1972, indicative of both the comparable quality of the two datasets and the probable lack of significant widespread bias in the land-based measurements due to urban development. The results of this study underscore the need for dense and geographically comprehensive measurements from both land and ocean areas and from both hemispheres in analyzing the global behavior of the earth's climate.

  7. Air-sea temperature decoupling in western Europe during the last interglacial-glacial transition

    NASA Astrophysics Data System (ADS)

    Sánchez Goñi, María Fernanda; Bard, Edouard; Landais, Amaelle; Rossignol, Linda; D'Errico, Francesco

    2013-10-01

    A period of continental ice growth between about 80,000 and 70,000 years ago was controlled by a decrease in summer insolation, and was among the four largest ice expansions of the past 250,000 years. The moisture source for this ice sheet expansion, known as the Marine Isotope Stage (MIS) 5a/4 transition, has been proposed to be the warm subpolar and northern subtropical Atlantic Ocean. However, the mechanism by which glaciers kept growing through three suborbital cooling events within this period, which were associated with iceberg discharge in the North Atlantic and cooling over Greenland, is unclear. Here we reconstruct parallel records of sea surface and air temperatures from marine microfossil and pollen data, respectively, from two sediment cores collected within the northern subtropical gyre. The thermal gradient between the cold air and warmer sea increased throughout the MIS5a/4 transition, and was marked by three intervals of even more pronounced thermal gradients associated with the C20, C19 and C18' cold events. We argue that the warm ocean surface along the western European margin provided a source of moisture that was transported, through northward-tracking storms, to feed ice sheets in colder Greenland, northern Europe and the Arctic.

  8. Characteristics of easterly-induced snowfall in Yeongdong and its relationship to air-sea temperature difference

    NASA Astrophysics Data System (ADS)

    Nam, Hyoung-Gu; Kim, Byung-Gon; Han, Sang-Ok; Lee, Chulkyu; Lee, Seoung-Soo

    2014-08-01

    Characteristics of snowfall episodes have been investigated for the past ten years in order to study its association with lowlevel stability and air-sea temperature difference over the East Sea. In general, the selected snowfall episodes have similar synoptic setting such as the Siberian High extended to northern Japan along with the Low passing by the southern Korean Peninsula, eventually resulting in the easterly flow in the Yeongdong region. Especially in the heavy snowfall episodes, convective unstable layers have been identified over the East sea due to relatively warm sea surface temperature (SST) about 8˜10°C and specifically cold pool around 1˜2 km above the surface level (ASL), which can be derived from Regional Data Assimilation and Prediction System (RDAPS), but that have not been clearly exhibited in the weak snowfall episodes. The basic mechanism to initiate snowfall around Yeongdong seems to be similar to that of lake-effect snowstorms around Great Lakes in the United States (Kristovich et al., 2003). Difference of equivalent potential temperature ( θ e ) between 850 hPa and surface as well as difference between air and sea temperatures altogether gradually began to increase in the pre-snowfall period and reached their maximum values in the course of the period, whose air (850 hPa) — sea temperature difference and snowfall intensity in case of the heavy snowfall episodes are almost larger than 20°C and 6 tims greater than the weak snowfall episodes, respectively. Interestingly, snowfall appeared to begin in case of an air-sea temperature difference exceeding over 15°C. The current analysis is overall consistent with the previous finding (Lee et al., 2012) that an instabilityinduced moisture supply to the lower atmosphere from the East sea, being cooled and saturated in the lower layer, so to speak, East Sea-Effect Snowfall (SES), would make a low-level ice cloud which eventually moves inland by the easterly flow. In addition, a longlasting

  9. Biases in the air-sea flux of CO2 resulting from ocean surface temperature gradients

    NASA Astrophysics Data System (ADS)

    Ward, B.; Wanninkhof, R.; McGillis, W. R.; Jessup, A. T.; Degrandpre, M. D.; Hare, J. E.; Edson, J. B.

    2004-08-01

    The difference in the fugacities of CO2 across the diffusive sublayer at the ocean surface is the driving force behind the air-sea flux of CO2. Bulk seawater fugacity is normally measured several meters below the surface, while the fugacity at the water surface, assumed to be in equilibrium with the atmosphere, is measured several meters above the surface. Implied in these measurements is that the fugacity values are the same as those across the diffusive boundary layer. However, temperature gradients exist at the interface due to molecular transfer processes, resulting in a cool surface temperature, known as the skin effect. A warm layer from solar radiation can also result in a heterogeneous temperature profile within the upper few meters of the ocean. Here we describe measurements carried out during a 14-day study in the equatorial Pacific Ocean (GasEx-2001) aimed at estimating the gradients of CO2 near the surface and resulting flux anomalies. The fugacity measurements were corrected for temperature effects using data from the ship's thermosalinograph, a high-resolution profiler (SkinDeEP), an infrared radiometer (CIRIMS), and several point measurements at different depths on various platforms. Results from SkinDeEP show that the largest cool skin and warm layer biases occur at low winds, with maximum biases of -4% and +4%, respectively. Time series ship data show an average CO2 flux cool skin retardation of about 2%. Ship and drifter data show significant CO2 flux enhancement due to the warm layer, with maximums occurring in the afternoon. Temperature measurements were compared to predictions based on available cool skin parameterizations to predict the skin-bulk temperature difference, along with a warm layer model.

  10. Relationships Between the Bulk-Skin Sea Surface Temperature Difference, Wind, and Net Air-Sea Heat Flux

    NASA Technical Reports Server (NTRS)

    Emery, William J.; Castro, Sandra L.; Lindstrom, Eric (Technical Monitor)

    2002-01-01

    The primary purpose of this project was to evaluate and improve models for the bulk-skin temperature difference to the point where they could accurately and reliably apply under a wide variety of environmental conditions. To accomplish this goal, work was conducted in three primary areas. These included production of an archive of available data sets containing measurements of the skin and bulk temperatures and associated environmental conditions, evaluation of existing skin layer models using the compiled data archive, and additional theoretical work on the development of an improved model using the data collected under diverse environmental conditions. In this work we set the basis for a new physical model of renewal type, and propose a parameterization for the temperature difference across the cool skin of the ocean in which the effects of thermal buoyancy, wind stress, and microscale breaking are all integrated by means of the appropriate renewal time scales. Ideally, we seek to obtain a model that will accurately apply under a wide variety of environmental conditions. A summary of the work in each of these areas is included in this report. A large amount of work was accomplished under the support of this grant. The grant supported the graduate studies of Sandra Castro and the preparation of her thesis which will be completed later this year. This work led to poster presentations at the 1999 American Geophysical Union Fall Meeting and 2000 IGARSS meeting. Additional work will be presented in a talk at this year's American Meteorological Society Air-Sea Interaction Meeting this May. The grant also supported Sandra Castro during a two week experiment aboard the R/P Flip (led by Dr. Andrew Jessup of the Applied Physics Laboratory) to help obtain additional shared data sets and to provide Sandra with a fundamental understanding of the physical processes needed in the models. In a related area, the funding also partially supported Dr. William Emery and Daniel

  11. Sensitivity of Global Sea-Air CO2 Flux to Gas Transfer Algorithms, Climatological Wind Speeds, and Variability of Sea Surface Temperature and Salinity

    NASA Technical Reports Server (NTRS)

    McClain, Charles R.; Signorini, Sergio

    2002-01-01

    Sensitivity analyses of sea-air CO2 flux to gas transfer algorithms, climatological wind speeds, sea surface temperatures (SST) and salinity (SSS) were conducted for the global oceans and selected regional domains. Large uncertainties in the global sea-air flux estimates are identified due to different gas transfer algorithms, global climatological wind speeds, and seasonal SST and SSS data. The global sea-air flux ranges from -0.57 to -2.27 Gt/yr, depending on the combination of gas transfer algorithms and global climatological wind speeds used. Different combinations of SST and SSS global fields resulted in changes as large as 35% on the oceans global sea-air flux. An error as small as plus or minus 0.2 in SSS translates into a plus or minus 43% deviation on the mean global CO2 flux. This result emphasizes the need for highly accurate satellite SSS observations for the development of remote sensing sea-air flux algorithms.

  12. Low-frequency variability of surface air temperature over the Barents Sea: causes and mechanisms

    NASA Astrophysics Data System (ADS)

    van der Linden, Eveline C.; Bintanja, Richard; Hazeleger, Wilco; Graversen, Rune G.

    2016-08-01

    The predominant decadal to multidecadal variability in the Arctic region is a feature that is not yet well-understood. It is shown that the Barents Sea is a key region for Arctic-wide variability. This is an important topic because low-frequency changes in the ocean might lead to large variations in the sea-ice cover, which then cause massive changes in the ocean-atmosphere heat exchanges. Here we describe the mechanism driving surface temperatures and heat fluxes in the Barents Sea based primarily on analyzes of one global coupled climate model. It is found that the ocean drives the low-frequency changes in surface temperature, whereas the atmosphere compensates the oceanic transport anomalies. The seasonal dependence and the role of individual components of the ocean-atmosphere energy budget are analyzed in detail, showing that seasonally-varying climate mechanisms play an important role. Herein, sea ice is governing the seasonal response, by acting as a lid that opens and closes during warm and cold periods, respectively, thereby modulating the surface heat fluxes.

  13. The Relation Between Wind Speed and Air-Sea Temperature Difference in the Marine Atmospheric Boundary Layer off Northwest Europe

    NASA Astrophysics Data System (ADS)

    Kettle, A. J.

    2014-12-01

    Wind speed and atmospheric stability have an important role in determining the turbulence in the marine atmospheric boundary layer (MABL) as well as the surface wave field. The understanding of MABL dynamics in northwest Europe is complicated by fetch effects, the proximity of coastlines, shallow topography, and larger scale circulation patterns (e.g., cold air outbreaks). Numerical models have difficulty simulating the marine atmospheric boundary layer in coastal areas and partially enclosed seas, and this is partly due to spatial resolution problems at coastlines. In these offshore environments, the boundary layer processes are often best understood directly from time series measurements from fixed platforms or buoys, in spite of potential difficulties from platform flow distortion as well as the spatial sparseness of the data sets. This contribution presents the results of time series measurements from offshore platforms in the North Sea and Norwegian Sea in terms of a summary diagnostic - wind speed versus air-sea temperature difference (U-ΔT) - with important implications for understanding atmospheric boundary layer processes. The U-ΔT diagram was introduced in earlier surveys of data from coastal (Sletringen; O.J. Andersen and J. Løvseth, J. Wind Eng. Ind. Aerodyn., 57, 97-109, 1995) and offshore (Statfjord A; K.J. Eidsvik, Boundary-Layer Meteorol., 32, 103-132, 1985) sites in northwest Europe to summarize boundary layer conditions at a given location. Additional information from a series of measurement purpose-built offshore measurement and oil/gas production platforms from the southern North Sea to the Norwegian Sea illustrates how the wind characteristics vary spatially over large distances, highlighting the influence of cold air outbreaks, in particular. The results are important for the offshore wind industry because of the way that wind turbines accrue fatigue damage in different conditions of atmospheric stability and wind speed.

  14. Coral Sr/Ca-based sea surface temperature and air temperature variability from the inshore and offshore corals in the Seribu Islands, Indonesia.

    PubMed

    Cahyarini, Sri Yudawati; Zinke, Jens; Troelstra, Simon; Suharsono; Aldrian, Edvin; Hoeksema, B W

    2016-09-30

    The ability of massive Porites corals to faithfully record temperature is assessed. Porites corals from Kepulauan Seribu were sampled from one inshore and one offshore site and analyzed for their Sr/Ca variation. The results show that Sr/Ca of the offshore coral tracked SST, while Sr/Ca variation of the inshore coral tracked ambient air temperature. In particular, the inshore SST variation is related to air temperature anomalies of the urban center of Jakarta. The latter we relate to air-sea interactions modifying inshore SST associated with the land-sea breeze mechanism and/or monsoonal circulation. The correlation pattern of monthly coral Sr/Ca with the Niño3.4 index and SEIO-SST reveals that corals in the Seribu islands region respond differently to remote forcing. An opposite response is observed for inshore and offshore corals in response to El Niño onset, yet similar to El Niño mature phase (December to February). SEIO SSTs co-vary strongly with SST and air temperature variability across the Seribu island reef complex. The results of this study clearly indicate that locations of coral proxy record in Indonesia need to be chosen carefully in order to identify the seasonal climate response to local and remote climate and anthropogenic forcing. PMID:27181035

  15. Stress induced by hooking, net towing, elevated sea water temperature and air in sablefish: Lack of concordance between mortality and physiological measures of stress

    USGS Publications Warehouse

    Davis, M.W.; Olla, B.L.; Schreck, C.B.

    2001-01-01

    In a series of laboratory studies designed to simulate bycatch processes, sablefish Anoplopoma fimbria were either hooked for up to 24 h or towed in a net for 4 h and then subjected to an abrupt transfer to elevated sea water temperature and air. Mortality did not result from hooking or net towing followed by exposure to air, but increased for both capture methods as fish were exposed to elevated temperatures, reflecting the magnifying effect of elevated temperature on mortality. Hooking and exposure to air resulted in increased plasma cortisol and lactate concentrations, while the combination of hooking and exposure to elevated temperature and air resulted in increased lactate and potassium concentrations. In fish that were towed in a net and exposed to air, cortisol, lactate, potassium and sodium concentrations increased, but when subjected to elevated temperature and air, no further increases occurred above the concentrations induced by net towing and air, suggesting a possible maximum of the physiological stress response. The results suggest that caution should be exercised when using physiological measures to quantify stress induced by capture and exposure to elevated temperature and air, that ultimately result in mortality, since the connections between physiological stress and mortality in bycatch processes remain to be fully understood.

  16. MODIS Global Sea Surface Temperature

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Every day the Moderate-resolution Imaging Spectroradiometer (MODIS) measures sea surface temperature over the entire globe with high accuracy. This false-color image shows a one-month composite for May 2001. Red and yellow indicates warmer temperatures, green is an intermediate value, while blues and then purples are progressively colder values. The new MODIS sea surface temperature product will be particularly useful in studies of temperature anomalies, such as El Nino, as well as research into how air-sea interactions drive changes in weather and climate patterns. In the high resolution image, notice the amazing detail in some of the regional current patterns. For instance, notice the cold water currents that move from Antarctica northward along South America's west coast. These cold, deep waters upwell along an equatorial swath around and to the west of the Galapagos Islands. Note the warm, wide currents of the Gulf Stream moving up the United States' east coast, carrying Caribbean warmth toward Newfoundland and across the Atlantic toward Western Europe. Note the warm tongue of water extending from Africa's east coast to well south of the Cape of Good Hope. MODIS was launched in December 1999 aboard NASA's Terra satellite. For more details on this and other MODIS data products, please see NASA Unveils Spectacular Suite of New Global Data Products from MODIS. Image courtesy MODIS Ocean Group, NASA GSFC, and the University of Miami

  17. Error estimations of dry deposition velocities of air pollutants using bulk sea surface temperature under common assumptions

    NASA Astrophysics Data System (ADS)

    Lan, Yung-Yao; Tsuang, Ben-Jei; Keenlyside, Noel; Wang, Shu-Lun; Arthur Chen, Chen-Tung; Wang, Bin-Jye; Liu, Tsun-Hsien

    2010-07-01

    It is well known that skin sea surface temperature (SSST) is different from bulk sea surface temperature (BSST) by a few tenths of a degree Celsius. However, the extent of the error associated with dry deposition (or uptake) estimation by using BSST is not well known. This study tries to conduct such an evaluation using the on-board observation data over the South China Sea in the summers of 2004 and 2006. It was found that when a warm layer occurred, the deposition velocities using BSST were underestimated within the range of 0.8-4.3%, and the absorbed sea surface heat flux was overestimated by 21 W m -2. In contrast, under cool skin only conditions, the deposition velocities using BSST were overestimated within the range of 0.5-2.0%, varying with pollutants and the absorbed sea surface heat flux was underestimated also by 21 W m -2. Scale analysis shows that for a slightly soluble gas (e.g., NO 2, NO and CO), the error in the solubility estimation using BSST is the major source of the error in dry deposition estimation. For a highly soluble gas (e.g., SO 2), the error in the estimation of turbulent heat fluxes and, consequently, aerodynamic resistance and gas-phase film resistance using BSST is the major source of the total error. In contrast, for a medium soluble gas (e.g., O 3 and CO 2) both the errors from the estimations of the solubility and aerodynamic resistance are important. In addition, deposition estimations using various assumptions are discussed. The largest uncertainty is from the parameterizations for chemical enhancement factors. Other important areas of uncertainty include: (1) various parameterizations for gas-transfer velocity; (2) neutral-atmosphere assumption; (3) using BSST as SST, and (4) constant pH value assumption.

  18. On the calculation of air-sea fluxes of CO2 in the presence of temperature and salinity gradients

    NASA Astrophysics Data System (ADS)

    Woolf, D. K.; Land, P. E.; Shutler, J. D.; Goddijn-Murphy, L. M.; Donlon, C. J.

    2016-02-01

    The presence of vertical temperature and salinity gradients in the upper ocean and the occurrence of variations in temperature and salinity on time scales from hours to many years complicate the calculation of the flux of carbon dioxide (CO2) across the sea surface. Temperature and salinity affect the interfacial concentration of aqueous CO2 primarily through their effect on solubility with lesser effects related to saturated vapor pressure and the relationship between fugacity and partial pressure. The effects of temperature and salinity profiles in the water column and changes in the aqueous concentration act primarily through the partitioning of the carbonate system. Climatological calculations of flux require attention to variability in the upper ocean and to the limited validity of assuming "constant chemistry" in transforming measurements to climatological values. Contrary to some recent analysis, it is shown that the effect on CO2 fluxes of a cool skin on the sea surface is large and ubiquitous. An opposing effect on calculated fluxes is related to the occurrence of warm layers near the surface; this effect can be locally large but will usually coincide with periods of low exchange. A salty skin and salinity anomalies in the upper ocean also affect CO2 flux calculations, though these haline effects are generally weaker than the thermal effects.

  19. A diagram of wind speed versus air-sea temperature difference to understand the dynamics of the marine atmospheric boundary layer off northwest Europe

    NASA Astrophysics Data System (ADS)

    Kettle, Anthony

    2015-04-01

    Wind speed and atmospheric stability have an important role in determining the turbulence in the marine atmospheric boundary layer (MABL) as well as the surface wave field. The understanding of MABL dynamics in northwest Europe is complicated by fetch effects, the proximity of coastlines, shallow topography, and larger scale circulation patterns (e.g., cold air outbreaks). Numerical models have difficulty simulating the marine atmospheric boundary layer in coastal areas and partially enclosed seas, and this is partly due to spatial resolution problems at land-sea coastline discontinuities. In these offshore environments, the boundary layer processes are often best understood directly from time series measurements from measurement platforms or buoys, in spite of potential difficulties from platform flow distortion as well as the spatial sparseness of the data sets. This contribution presents updated results of measurements from offshore platforms in the North Sea and Norwegian Sea in terms of a summary diagnostic - wind speed versus air-sea temperature difference (U-ΔT) - with important implications for understanding atmospheric boundary layer processes. The U-ΔT diagram was introduced in earlier surveys of data from coastal and offshore sites in northwest Europe to summarize boundary layer conditions at a given location. Additional information from a series of measurement purpose-built offshore measurement and oil/gas production platforms from the North Sea illustrates how the wind characteristics vary spatially over large distances. The results are important for the offshore wind industry because of the way that wind turbines accrue fatigue damage in different conditions of atmospheric stability and wind speed.

  20. The Relation between Indian Monsoon Rainfall, the Southern Oscillation, and Hemispheric Air and Sea Temperature: 1884-1984.

    NASA Astrophysics Data System (ADS)

    Elliott, W. P.; Angell, J. K.

    1987-08-01

    Correlations between the June-September Indian monsoon rainfall and Santiago minus Darwin pressure, Tahiti minus Darwin pressure, and Wright's Southern Oscillation index, as well as the individual station pressure deviations themselves, show that the monsoon rainfall anticipates the Southern Oscillation Indices and the individual pressure deviations with the exception of the pressure at Santiago. Monsoon rainfall is also negatively correlated with sea surface temperatures in the eastern equatorial Pacific one to two seasons later. The correlations suggest that above average monsoon rainfall is associated with below average Southern Hemisphere temperatures two to three seasons later, whereas above average Northern Hemisphere winter temperatures-particularly continental temperatures-anticipate above average rainfall. The correlations with hemispheric temperatures are significant only since about 1947, however. A strong negative correlation (0.64) between the seasonal change in Darwin's pressure deviation from December-February to March-May prior to the monsoon, and monsoon rainfall is found in the period 1947-84, but only weakly in the period before 1947.

  1. Annual sea ice. An air-sea gas exchange moderator

    SciTech Connect

    Gosink, T.A.; Kelley, J.J.

    1982-01-01

    Arctic annual sea ice, particularly when it is relatively warm (> -15/sup 0/C) permits significant gas exchange between the sea and air throughout the entire year. Sea ice, particularly annual sea ice, differs from freshwater ice with respect to its permeability to gases. The presence of brine allows for significant air-sea-ice exchange of CO/sub 2/ throughout the winter, which may significantly affect the global carbon dioxide balance. Other trace gases are also noted to be enriched in sea ice, but less is known about their importance to air-sea-interactions at this time. Both physical and biological factors cause and modify evolution of gases from the surface of sea ice. Quantitative and qualitative descriptions of the nature and physical behavior of sea ice with respect to brine and gases are discussed.

  2. Separating the influence of projected changes in air temperature and wind on patterns of sea level change and ocean heat content

    NASA Astrophysics Data System (ADS)

    Saenko, Oleg A.; Yang, Duo; Gregory, Jonathan M.; Spence, Paul; Myers, Paul G.

    2015-08-01

    We present ocean model sensitivity experiments aimed at separating the influence of the projected changes in the "thermal" (near-surface air temperature) and "wind" (near-surface winds) forcing on the patterns of sea level and ocean heat content. In the North Atlantic, the distribution of sea level change is more due to the "thermal" forcing, whereas it is more due to the "wind" forcing in the North Pacific; in the Southern Ocean, the "thermal" and "wind" forcing have a comparable influence. In the ocean adjacent to Antarctica the "thermal" forcing leads to an inflow of warmer waters on the continental shelves, which is somewhat attenuated by the "wind" forcing. The structure of the vertically integrated heat uptake is set by different processes at low and high latitudes: at low latitudes it is dominated by the heat transport convergence, whereas at high latitudes it represents a small residual of changes in the surface flux and advection of heat. The structure of the horizontally integrated heat content tendency is set by the increase of downward heat flux by the mean circulation and comparable decrease of upward heat flux by the subgrid-scale processes; the upward eddy heat flux decreases and increases by almost the same magnitude in response to, respectively, the "thermal" and "wind" forcing. Regionally, the surface heat loss and deep convection weaken in the Labrador Sea, but intensify in the Greenland Sea in the region of sea ice retreat. The enhanced heat flux anomaly in the subpolar Atlantic is mainly caused by the "thermal" forcing.

  3. Interannual and seasonal variabilities in air-sea CO2 fluxes along the U.S. eastern continental shelf and their sensitivity to increasing air temperatures and variable winds

    NASA Astrophysics Data System (ADS)

    Cahill, Bronwyn; Wilkin, John; Fennel, Katja; Vandemark, Doug; Friedrichs, Marjorie A. M.

    2016-02-01

    Uncertainty in continental shelf air-sea CO2 fluxes motivated us to investigate the impact of interannual and seasonal variabilities in atmospheric forcing on the capacity of three shelf regions along the U.S. eastern continental shelf to act as a sink or source of atmospheric CO2. Our study uses a coupled biogeochemical-circulation model to simulate scenarios of "present-day" and "future-perturbed" mesoscale forcing variability. Overall, the U.S. eastern continental shelf acts as a sink for atmospheric CO2. There is a clear gradient in air-sea CO2 flux along the shelf region, with estimates ranging from -0.6 Mt C yr-1 in the South Atlantic Bight (SAB) to -1.0 Mt C yr-1 in the Mid-Atlantic Bight (MAB) and -2.5 Mt C yr-1 in the Gulf of Maine (GOM). These fluxes are associated with considerable interannual variability, with the largest interannual signal exhibited in the Gulf of Maine. Seasonal variability in the fluxes is also evident, with autumn and winter being the strongest CO2 sink periods and summer months exhibiting some outgassing. In our future-perturbed scenario spatial differences tend to cancel each other out when the fluxes are integrated over the MAB and GOM, resulting in only minor differences between future-perturbed and present-day air-sea CO2 fluxes. This is not the case in the SAB where the position of the along-shelf gradient shifts northward and the SAB becomes a source of CO2 to the atmosphere (0.7 Mt C yr-1) primarily in response to surface warming. Our results highlight the importance of temperature in regulating air-sea CO2 flux variability.

  4. Air-sea interactions during strong winter extratropical storms

    NASA Astrophysics Data System (ADS)

    Nelson, Jill; He, Ruoying; Warner, John C.; Bane, John

    2014-09-01

    A high-resolution, regional coupled atmosphere-ocean model is used to investigate strong air-sea interactions during a rapidly developing extratropical cyclone (ETC) off the east coast of the USA. In this two-way coupled system, surface momentum and heat fluxes derived from the Weather Research and Forecasting model and sea surface temperature (SST) from the Regional Ocean Modeling System are exchanged via the Model Coupling Toolkit. Comparisons are made between the modeled and observed wind velocity, sea level pressure, 10 m air temperature, and sea surface temperature time series, as well as a comparison between the model and one glider transect. Vertical profiles of modeled air temperature and winds in the marine atmospheric boundary layer and temperature variations in the upper ocean during a 3-day storm period are examined at various cross-shelf transects along the eastern seaboard. It is found that the air-sea interactions near the Gulf Stream are important for generating and sustaining the ETC. In particular, locally enhanced winds over a warm sea (relative to the land temperature) induce large surface heat fluxes which cool the upper ocean by up to 2 °C, mainly during the cold air outbreak period after the storm passage. Detailed heat budget analyses show the ocean-to-atmosphere heat flux dominates the upper ocean heat content variations. Results clearly show that dynamic air-sea interactions affecting momentum and buoyancy flux exchanges in ETCs need to be resolved accurately in a coupled atmosphere-ocean modeling framework.

  5. Linking phytoplankton community size composition with temperature, plankton food web structure and sea-air CO 2 flux

    NASA Astrophysics Data System (ADS)

    Hilligsøe, Karen Marie; Richardson, Katherine; Bendtsen, Jørgen; Sørensen, Lise-Lotte; Nielsen, Torkel Gissel; Lyngsgaard, Maren Moltke

    2011-08-01

    Data collected at open water stations (depth>400 m) in all major ocean basins in 2006-2008 are used to examine the relationship between the size structure of the phytoplankton community (determined by size fractionated chlorophyll filtration), temperature and inorganic nutrient availability. A significant relationship ( p<0.0005) was found between community size structure and temperature, with the importance of large cells in the community decreasing with increase in temperature. Although weaker than the temperature relationship, significant relationships were also noted between community cell size and DIN (nitrate, nitrite and ammonium: p=0.034) and phosphate ( p=0.031) concentrations. When the data were divided into two groups of equal size, representing the samples with the highest and lowest DIN/phosphate concentrations, respectively, no difference could be identified between the slopes of the lines representing the relationship between size structure and temperature. There was, however, a difference in the intercepts between the two groups. If the relationship between size and temperature was only a response to nutrient availability, we would expect that the response would be the strongest in the groups with the lowest nutrient concentrations. These results suggest that, in addition to a nutrient effect, temperature may also directly influence the size structure of phytoplankton communities. The size structure of the phytoplankton community in this study correlated to the magnitude of primary production, export production (determined after Laws et al., 2000) and integrated water column chlorophyll. Significant relationships were also found between mesozooplankton production (determined using the proxy of calanoid+cyclopoid nauplii abundance as a percentage of the total number of these copepods) and both temperature and phytoplankton size, with production being the lowest in the warmest waters where phytoplankton were the smallest. In the North Atlantic, export

  6. Atlantic Air-Sea Interaction Revisited

    NASA Astrophysics Data System (ADS)

    Rodwell, M. J.

    INTRODUCTION DATA AND MODELS THE ANALYSIS METHOD ATMOSPHERIC FORCING OF NORTH ATLANTIC SEA SURFACE TEMPERATURES NORTH ATLANTIC SEA SURFACE TEMPERATURE FORCING OF THE ATMOSPHERE Observational Evidence Model Results POTENTIAL SEASONAL PREDICTABILITY BASED ON THE ATMOSPHERE GENERAL - CIRCULATION MODEL CONCLUSIONS AND DISCUSSION REFERENCES

  7. Sea surface temperature - Observations from geostationary satellites

    NASA Technical Reports Server (NTRS)

    Bates, J. J.; Smith, W. L.

    1985-01-01

    Multispectral image data acquired from the VISSR atmospheric sounder (VAS) on the geostationary GOES satellites were used to estimate sea surface temperatures (SST). A procedure was developed to screen VAS visible and infrared data for cloud-free regions for estimation of SST from the clear infrared radiances. A data set of matches between the VAS radiances and high quality buoy estimates of SST was produced. A linear regression analysis of these matches was performed to generate an empirical algorithm relating the VAS window channel brightness temperatures to the estimates of SST recorded by NOAA fixed environment buoys. Daily maps of SST during Hurricanes Alicia (1983) and Debbie (1982) demonstrated the ability of VAS to monitor air-sea interactions at high temporal and spatial scales.

  8. Air-sea interactions during strong winter extratropical storms

    USGS Publications Warehouse

    Nelson, Jill; He, Ruoying; Warner, John C.; Bane, John

    2014-01-01

    A high-resolution, regional coupled atmosphere–ocean model is used to investigate strong air–sea interactions during a rapidly developing extratropical cyclone (ETC) off the east coast of the USA. In this two-way coupled system, surface momentum and heat fluxes derived from the Weather Research and Forecasting model and sea surface temperature (SST) from the Regional Ocean Modeling System are exchanged via the Model Coupling Toolkit. Comparisons are made between the modeled and observed wind velocity, sea level pressure, 10 m air temperature, and sea surface temperature time series, as well as a comparison between the model and one glider transect. Vertical profiles of modeled air temperature and winds in the marine atmospheric boundary layer and temperature variations in the upper ocean during a 3-day storm period are examined at various cross-shelf transects along the eastern seaboard. It is found that the air–sea interactions near the Gulf Stream are important for generating and sustaining the ETC. In particular, locally enhanced winds over a warm sea (relative to the land temperature) induce large surface heat fluxes which cool the upper ocean by up to 2 °C, mainly during the cold air outbreak period after the storm passage. Detailed heat budget analyses show the ocean-to-atmosphere heat flux dominates the upper ocean heat content variations. Results clearly show that dynamic air–sea interactions affecting momentum and buoyancy flux exchanges in ETCs need to be resolved accurately in a coupled atmosphere–ocean modeling framework.

  9. Air-sea interactions and precipitation over the tropical oceans

    NASA Technical Reports Server (NTRS)

    Gautier, C.

    1992-01-01

    In this lecture, the author principally discusses air-sea exchanges that are relevant to climate and global problems. The processes of interest are those acting over time scales of months to decades, which in some instances are influenced by smaller-time-scale processes, down to the diurnal time scale. The repsective influence of these processes varies with regions, seasons and scales over which they occur and, because these processes are mostly nonlinear, scale interactions can be quite complex. Owing to the breadth of the topic addressed, the discussion is mostly focused on the tropical regions where air-sea interactions and precipitation processes eventually affect the entire globe. This allows a look in more detail at some air-sea processes, such as those associated with the El Nino southern oscillation (ENSO). This oscillation, which affects the climate of the entire globe, acts over periods of a year or longer and is caused, primarily, by sea surface temperature (SST) variations in the tropical Pacific. As a result, SST variability is often used as an indicator of coupled ocean-atmosphere low-frequency variability. Global or basin scale processes can uniquely be observed from space-born instruments with the coverage required. Space based techniques have been developed during the last decade which can now be used to illustrate the scientific issues presented and the presentation concludes with an overview of some Earth Observing System (EOS) capabilities for addressing air-sea interactions and hydrology issues.

  10. Impact of Sea Spray on Air-Sea Fluxes

    NASA Astrophysics Data System (ADS)

    Veron, Fabrice; Mueller, James

    2013-11-01

    The contributions of sea spray drops to the total air-sea exchanges of momentum, heat, and mass remain an open question. A number of factors obscure any simple quantification of their contribution: the number of drops formed at the ocean surface and the per-drop contribution to the fluxes. To estimate these per-droplet fluxes, we present results from a large number of drop trajectories, which are simulated with a recently developed Lagrangian Stochastic model adapted for the heavy drop transport and evaporation within the marine boundary layer. Then, using commonly accepted spray generation functions we present estimates of spray fluxes which account for the mediating feedback effects from the droplets on the atmosphere. The results suggest that common simplifications in previous sea spray models, such as the residence time in the marine boundary layer, may not be appropriate. We further show that the spray fluxes may be especially sensitive to the size distribution of the drops. The total effective air-sea fluxes lead to drag and enthalpy coefficients that increase modestly with wind speed. The rate of increase for the drag coefficient is greatest at moderate wind speeds, while the rate of increase for the enthalpy coefficient is greatest at higher wind speeds. Funded by grants OCE-0850663 and OCE-0748767 from the National Science Foundation.

  11. Climatic impacts of stochastic fluctuations in air-sea fluxes

    NASA Astrophysics Data System (ADS)

    Williams, Paul D.

    2012-05-01

    Air-sea fluxes vary partly on scales that are too small or fast to be resolved explicitly by global climate models. This paper proposes a nonlinear physical mechanism by which stochastic fluctuations in the air-sea buoyancy flux may modify the mean climate. The paper then demonstrates the mechanism in climate simulations with a comprehensive coupled general circulation model. Significant changes are detected in the time-mean oceanic mixed-layer depth, sea-surface temperature, atmospheric Hadley circulation, and net upward water flux at the sea surface. Also, El Niño Southern Oscillation (ENSO) variability is significantly increased. The findings demonstrate that noise-induced drift and noise-enhanced variability, which are familiar concepts from simple climate models, continue to apply in comprehensive climate models with millions of degrees of freedom. The findings also suggest that the lack of representation of sub-grid variability in air-sea fluxes may contribute to some of the biases exhibited by contemporary climate models.

  12. New satellite record of sea surface temperature

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2013-02-01

    Sea surface temperature is one of the key variables scientists track in studying climate changes; it is also important to meteorology and oceanography. Merchant et al. describe a new 20-year record of sea surface temperature. The record was created using infrared imagery from the Along-Track Scanning Radiometers (ATSR) as part of the ATSR Reprocessing for Climate (ARC) project.

  13. Temperature impacts on deep-sea biodiversity.

    PubMed

    Yasuhara, Moriaki; Danovaro, Roberto

    2016-05-01

    Temperature is considered to be a fundamental factor controlling biodiversity in marine ecosystems, but precisely what role temperature plays in modulating diversity is still not clear. The deep ocean, lacking light and in situ photosynthetic primary production, is an ideal model system to test the effects of temperature changes on biodiversity. Here we synthesize current knowledge on temperature-diversity relationships in the deep sea. Our results from both present and past deep-sea assemblages suggest that, when a wide range of deep-sea bottom-water temperatures is considered, a unimodal relationship exists between temperature and diversity (that may be right skewed). It is possible that temperature is important only when at relatively high and low levels but does not play a major role in the intermediate temperature range. Possible mechanisms explaining the temperature-biodiversity relationship include the physiological-tolerance hypothesis, the metabolic hypothesis, island biogeography theory, or some combination of these. The possible unimodal relationship discussed here may allow us to identify tipping points at which on-going global change and deep-water warming may increase or decrease deep-sea biodiversity. Predicted changes in deep-sea temperatures due to human-induced climate change may have more adverse consequences than expected considering the sensitivity of deep-sea ecosystems to temperature changes. PMID:25523624

  14. Analysis of sea level and sea surface temperature changes in the Black Sea

    NASA Astrophysics Data System (ADS)

    Betul Avsar, Nevin; Jin, Shuanggen; Kutoglu, Hakan; Erol, Bihter

    2016-07-01

    The Black Sea is a nearly closed sea with limited interaction with the Mediterranean Sea through the Turkish Straits. Measurement of sea level change will provide constraints on the water mass balance and thermal expansion of seawaters in response to climate change. In this paper, sea level changes in the Black Sea are investigated between January 1993 and December 2014 using multi-mission satellite altimetry data and sea surface temperature (SST) data. Here, the daily Maps of Sea Level Anomaly (MSLA) gridded with a 1/8°x1/8° spatial resolution from AVISO and the NOAA 1/4° daily Optimum Interpolation Sea Surface Temperature (OISST) Anomaly data set are used. The annual cycles of sea level and sea surface temperature changes reach the maximum values in November and January, respectively. The trend is 3.16±0.77 mm/yr for sea level change and -0.06±0.01°C/yr for sea surface temperature during the same 22-year period. The observed sea level rise is highly correlated with sea surface warming for the same time periods. In addition, the geographical distribution of the rates of the Black Sea level and SST changes between January 1993 and December 2014 are further analyzed, showing a good agreement in the eastern Black Sea. The rates of sea level rise and sea surface warming are larger in the eastern part than in the western part except in the northwestern Black Sea. Finally, the temporal correlation between sea level and SST time series are presented based on the Empirical Orthogonal Function (EOF) analysis.

  15. Air and sea rescue via satellite systems

    NASA Astrophysics Data System (ADS)

    Scales, W. C.; Swanson, R.

    1984-03-01

    Two approaches to a satellite system for air and sea rescue to be put into use by the 1990s, one employing polar-orbiting satellites and the other using fixed geosynchronous satellites over the equator, are discussed. A battery-powered transmitter on a ship or aircraft would be activated in an accident to emit a low-power omnidirectional signal that would be relayed by a satellite to an earth station. The polar-orbiting approach, now being evaluated on a small-scale with the Cospas-Sarsat system, allows complete coverage of the earth, including the poles, and provides a fix on the origin of the distress signals by means of the Doppler shift. A parallel effort for the testing of geostationary satellites to measure system sensitivity to various interference sources, to optimize design, and to measure land and sea performance is reviewed.

  16. Joint Air Sea Interaction (JASIN) experiment, Northwest coast of Scotland

    NASA Technical Reports Server (NTRS)

    Businger, J. A.

    1981-01-01

    The joint air sea interaction (JASIN) experiment took place off the Northwest coast of Scotland. Sea surface and boundary layer parameters were measured. The JASIN data was used as ground truth for various sensors on the SEASAT satellite.

  17. Air-sea interaction and spatial variability of the surface evaporation duct in a coastal environment

    NASA Astrophysics Data System (ADS)

    Brooks, Ian M.

    Aircraft observations are presented of the horizontal variability in the depth of the surface evaporation duct and the relationship with the mesoscale structure of air-sea interaction processes. The 2-dimensional fields of near-surface wind, stress, wind-stress curl, air and sea-surface temperature are measured directly for flow around a headland. The sea surface temperature field indicates cold upwelling driven by the wind-stress curl. Boundary-layer stability responds rapidly to the spatial changes in surface temperature. These changes result in modification of the evaporation duct, which decreases significantly in depth over the cooler upwelling water.

  18. In calm seas, precipitation drives air-sea gas exchange

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2012-05-01

    In a series of experiments run in what resembles a heavily instrumented fish tank, Harrison et al. investigated the interwoven roles of wind and rain on air-sea gas exchange rates. Working with a 42-meterlong, 1-meter-wide, and 1.25-meter-tall experimental pool, the authors were able to control the wind speed, rainfall rate, water circulation speed, and other parameters, which they used to assess the effect of 24 different wind speed-rainfall rate combinations on the gas exchange rate of sulfur hexafuoride, a greenhouse gas. In trials that lasted up to 3 hours, the authors collected water samples from the tank at regular intervals, tracking the concentration of the dissolved gas.

  19. High Lapse Rates in AIRS Retrieved Temperatures in Cold Air Outbreaks

    NASA Technical Reports Server (NTRS)

    Fetzer, Eric J.; Kahn, Brian; Olsen, Edward T.; Fishbein, Evan

    2004-01-01

    The Atmospheric Infrared Sounder (AIRS) experiment, on NASA's Aqua spacecraft, uses a combination of infrared and microwave observations to retrieve cloud and surface properties, plus temperature and water vapor profiles comparable to radiosondes throughout the troposphere, for cloud cover up to 70%. The high spectral resolution of AIRS provides sensitivity to important information about the near-surface atmosphere and underlying surface. A preliminary analysis of AIRS temperature retrievals taken during January 2003 reveals extensive areas of superadiabatic lapse rates in the lowest kilometer of the atmosphere. These areas are found predominantly east of North America over the Gulf Stream, and, off East Asia over the Kuroshio Current. Accompanying the high lapse rates are low air temperatures, large sea-air temperature differences, and low relative humidities. Imagery from a Visible / Near Infrared instrument on the AIRS experiment shows accompanying clouds. These lines of evidence all point to shallow convection in the bottom layer of a cold air mass overlying warm water, with overturning driven by heat flow from ocean to atmosphere. An examination of operational radiosondes at six coastal stations in Japan shows AIRS to be oversensitive to lower tropospheric lapse rates due to systematically warm near-surface air temperatures. The bias in near-surface air temperature is seen to be independent of sea surface temperature, however. AIRS is therefore sensitive to air-sea temperature difference, but with a warm atmospheric bias. A regression fit to radiosondes is used to correct AIRS near-surface retrieved temperatures, and thereby obtain an estimate of the true atmosphere-ocean thermal contrast in five subtropical regions across the north Pacific. Moving eastward, we show a systematic shift in this air-sea temperature differences toward more isothermal conditions. These results, while preliminary, have implications for our understanding of heat flow from ocean to

  20. Global sea level linked to global temperature

    PubMed Central

    Vermeer, Martin; Rahmstorf, Stefan

    2009-01-01

    We propose a simple relationship linking global sea-level variations on time scales of decades to centuries to global mean temperature. This relationship is tested on synthetic data from a global climate model for the past millennium and the next century. When applied to observed data of sea level and temperature for 1880–2000, and taking into account known anthropogenic hydrologic contributions to sea level, the correlation is >0.99, explaining 98% of the variance. For future global temperature scenarios of the Intergovernmental Panel on Climate Change's Fourth Assessment Report, the relationship projects a sea-level rise ranging from 75 to 190 cm for the period 1990–2100. PMID:19995972

  1. Long-term changes in sea surface temperatures

    SciTech Connect

    Parker, D.E.

    1994-12-31

    Historical observations of sea surface temperature since 1856 have been improved by applying corrections to compensate for the predominant use of uninsulated or partly insulated buckets until the Second World War. There are large gaps in coverage in the late nineteenth century and around the two world wars, but a range of statistical techniques suggest that these gaps do not severely prejudice estimates of global and regional climatic change. Nonetheless, to improve the analysis on smaller scales, many unused historical data are to be digitized and incorporated. For recent years, satellite-based sea surface temperatures have improved the coverage, after adjustments for their biases relative to in situ data. An initial version of a nominally globally complete sea ice and interpolated sea surface temperature data set, beginning in 1871, has been created for use in numerical simulations of recent climate. Long time series of corrected regional, hemispheric, and global sea surface temperatures are mostly consistent with corresponding night marine air temperature series, and confirm the regionally specific climatic changes portrayed in the Scientific Assessments of the intergovernmental Panel on Climate Change. The observations also show an El Nino-like oscillation on bidecadal and longer time scales.

  2. Tropical Cyclone Induced Air-Sea Interactions Over Oceanic Fronts

    NASA Astrophysics Data System (ADS)

    Shay, L.

    2012-04-01

    Recent severe tropical cyclones underscore the inherent importance of warm background ocean fronts and their interactions with the atmospheric boundary layer. Central to the question of heat and moisture fluxes from the ocean to the atmosphere, the amount of heat available to the tropical cyclone is predicated by the initial depth of the mixed layer and strength of the stratification level that set the level of entrainment mixing at the base of the oceanic mixed layer. For example in oceanic regimes where the ocean mixed layers are thin, shear-induced mixing tends to cool the upper ocean (and sea surface temperatures) quickly which reduces the air-sea fluxes. This is an example of negative feedback from the ocean to the atmosphere. By contrast, in regimes where the ocean mixed layers are deep (usually along the western part of the gyres), warm water advection by the nearly steady currents reduces the levels of turbulent mixing by shear instabilities. As these strong near-inertial shears are arrested, more heat and moisture is available through the sea surface. When tropical cyclones move into favorable or neutral atmospheric conditions (low vertical shear, anticyclonic circulation aloft), tropical cyclones have a tendency to rapidly intensify as observed over the Gulf of Mexico during Isidore and Lili in 2002, Katrina and Rita in 2005, Dean and Felix in 2007 in the Caribbean Sea, and Earl in 2010 just north of the Caribbean Islands. To predict these tropical cyclone deepening (as well as weakening) cycles, coupled models must have ocean models with realistic ocean conditions and accurate air-sea and vertical mixing parameterizations. These effects and possible impact on TC deepening and weakening underscores the necessity of having complete 3-D ocean measurements juxtaposed with atmospheric profiler measurements.

  3. Surface Temperature variability from AIRS.

    NASA Astrophysics Data System (ADS)

    Ruzmaikin, A.; Dang, V. T.; Aumann, H. H.

    2015-12-01

    To address the existence and possible causes of the climate hiatus in the Earth's global temperature we investigate the trends and variability in the surface temperature using retrievals obtained from the measurements by the Atmospheric Infrared Sounder (AIRS) and its companion instrument, the Advanced Microwave Sounding Unit (AMSU), onboard of Aqua spacecraft in 2002-2014for the day and night conditions. The data used are L3 monthly means on a 1x1degree spatial grid. We separate the land and ocean temperatures, as well as temperatures in Artic, Antarctic and desert regions. We compare the satellite data with the new surface data produced by Karl et al. (2015) who denies the reality of the climate hiatus. The difference in the regional trends can help to explain why the global surface temperature remains almost unchanged but the frequency of occurrence of the extreme events increases under rising anthropogenic forcing. The day-night difference is an indicator of the anthropogenic trend. This work was supported by the Jet Propulsion Laboratory of the California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  4. Air--Sea CO2 Cycling in the Southeastern Beaufort Sea

    NASA Astrophysics Data System (ADS)

    Else, Brent Gordon Thomas

    During the fourth International Polar Year, an interdisciplinary study was conducted to examine the couplings between sea ice, ocean, atmosphere, and ecosystem in the southeastern Beaufort Sea. This thesis examines components of the system that control the air-sea exchange of carbon dioxide. Using eddy covariance measurements, we found enhanced CO2 exchange associated with new ice formation in winter flaw leads. This exchange was typically directed towards the surface, although we also measured one instance of outgassing. Sea surface dissolved CO2 measurements (pCO 2sw) in Amundsen Gulf showed significant undersaturation with respect to the atmosphere at freeze-up, followed by a slow increase over the winter until spring phytoplankton blooms caused strong undersaturation at break-up. Over the summer, pCO2sw increased until becoming slightly supersaturated due to surface warming. Along the southern margins of Amundsen Gulf and on the Mackenzie Shelf we found pCO2sw supersaturations in the fall due to wind-driven coastal upwelling. In the spring, this upwelling occurred along the landfast ice edges of Amundsen Gulf. By combining observations of enhanced winter gas exchange with observations of pCO 2sw in Amundsen Gulf, we derived an annual budget of air-sea CO2 exchange for the region. This exercise showed that uptake through the winter season was as important as the open water season, making the overall annual uptake of CO2 about double what had previously been calculated. Prior to this work, the prevailing paradigm of airsea CO2 cycling in Arctic polynya regions posited that strong CO2 absorption occurs in the open water seasons, and that a potential outgassing during the winter is inhibited by the sea ice cover. As a new paradigm, we propose that the spatial and temporal variability of many processes---including phytoplankton blooms, sea surface temperature and salinity changes, upwelling, river input, continental shelf processes, and the potential for high rates

  5. Sea surface temperature and torrential rains in the Valencia region: modelling the role of recharge areas

    NASA Astrophysics Data System (ADS)

    Pastor, Francisco J.

    2016-04-01

    Heavy rain events are frequently recorded in the Western Mediterranean causing economic and human losses. A main factor in the development of torrential rains is ocean-atmosphere exchange of heat and moisture that can destabilize air masses travelling over the sea. The study of air mass trajectories previous to the rain event permits the identification of sea areas that could probably contribute to the development or intensification of rainfall. From a Mediterranean sea surface temperature climatology, its spatio-temporal distribution patterns have been studied showing two main distribution modes in winter and summer and transitional regimes in spring and autumn. Hence, three heavy precipitation events, for such winter and summer sea temperature regimes and for fall transition, affecting the Valencia region have been selected to study the effect of sea surface temperature in torrential rains. Simulations with perturbed sea surface temperature in different areas along the air mass path were run to compare results with unperturbed simulation. The variation of sea surface temperature in certain areas caused significant changes in model accumulated values and its spatial distribution. Therefore, the existence of areas that at a greater extent favour air-sea interaction leading to the development of torrential rainfall in the Valencia region is shown. This methodology could be extended to other Mediterranean regions to look for such potential recharge areas. The identification of sea areas that contribute to the development or intensification of heavy rain events in the Mediterranean countries could be a useful prognosis and/or monitoring tool.

  6. The potential role of sea spray droplets in facilitating air-sea gas transfer

    NASA Astrophysics Data System (ADS)

    Andreas, E. L.; Vlahos, P.; Monahan, E. C.

    2016-05-01

    For over 30 years, air-sea interaction specialists have been evaluating and parameterizing the role of whitecap bubbles in air-sea gas exchange. To our knowledge, no one, however, has studied the mirror image process of whether sea spray droplets can facilitate air-sea gas exchange. We are therefore using theory, data analysis, and numerical modeling to quantify the role of spray on air-sea gas transfer. In this, our first formal work on this subject, we seek the rate-limiting step in spray-mediated gas transfer by evaluating the three time scales that govern the exchange: τ air , which quantifies the rate of transfer between the atmospheric gas reservoir and the surface of the droplet; τ int , which quantifies the exchange rate across the air-droplet interface; and τ aq , which quantifies gas mixing within the aqueous solution droplet.

  7. Atmospheric variability and air-sea interaction

    NASA Technical Reports Server (NTRS)

    Middleton, J. W.; Reiter, E. R.

    1980-01-01

    The topics studied include: (1) processing of Northern Hemispheric precipitation data, in order to fill in the transition seasons to provide a continuous 40 year data base on the variability of continental precipitation; (2) comparison of seasonally averaged fields of sea surface temperature obtained from ship observations in the North Atlantic and North Pacific in 1970 with the corresponding fields inferred from satellite observations; (3) estimation of seasonal average of total precipitable water at those admittedly few oceanic stations where repeated vertical soundings were made in 1970 and comparison with corresponding values inferred from satellite measurements; (4) comparison of seasonally averaged evaporation fields determined from ground based observations in 1970 with the field of divergence of the seasonal total horizontal water vapor flux inferred from satellite total water measurements and NMC wind data for the lower troposphere; (5) examination of meaning of convection-inversion index.

  8. Twentieth-Century Sea Surface Temperature Trends

    PubMed

    Cane; Clement; Kaplan; Kushnir; Pozdnyakov; Seager; Zebiak; Murtugudde

    1997-02-14

    An analysis of historical sea surface temperatures provides evidence for global warming since 1900, in line with land-based analyses of global temperature trends, and also shows that over the same period, the eastern equatorial Pacific cooled and the zonal sea surface temperature gradient strengthened. Recent theoretical studies have predicted such a pattern as a response of the coupled ocean-atmosphere system to an exogenous heating of the tropical atmosphere. This pattern, however, is not reproduced by the complex ocean-atmosphere circulation models currently used to simulate the climatic response to increased greenhouse gases. Its presence is likely to lessen the mean 20th-century global temperature change in model simulations. PMID:9020074

  9. Lasers as probes for air and sea

    NASA Astrophysics Data System (ADS)

    Svanberg, S.

    1980-12-01

    The rapid development of quantum electronics has permitted the introduction of efficient remote-sensing techniques for air and sea, based on applied laser spectroscopy. In this paper basic interactions between laser light and molecules are discussed as a background for a description of laser probing of the atmosphere and the hydrosphere. For the atmosphere both meteorological parameters and pollution levels can be measured. Long-path absorption and lidar (laser radar) techniques yield average or range-resolved values for several environmental parameters. Tropospheric and stratospheric measurements of particles and gaseous pollutants are described. Laser light can be used for marine probing within the blue-green optical window of water. Much of the effort in this field aims at the development of airborne measuring systems. Bathymetric experiments and the detection of schools of fish are discussed. Laser-induced fluorescence can be used for airborne monitoring of pollutants like mineral oils and pulp-mill wastes. Accurate laboratory measurements of spectral 'signatures' of different materials are important.

  10. Sea-air boundary meteorological sensor

    NASA Astrophysics Data System (ADS)

    Barbosa, Jose G.

    2015-05-01

    The atmospheric environment can significantly affect radio frequency and optical propagation. In the RF spectrum refraction and ducting can degrade or enhance communications and radar coverage. Platforms in or beneath refractive boundaries can exploit the benefits or suffer the effects of the atmospheric boundary layers. Evaporative ducts and surface-base ducts are of most concern for ocean surface platforms and evaporative ducts are almost always present along the sea-air interface. The atmospheric environment also degrades electro-optical systems resolution and visibility. The atmospheric environment has been proven not to be uniform and under heterogeneous conditions substantial propagation errors may be present for large distances from homogeneous models. An accurate and portable atmospheric sensor to profile the vertical index of refraction is needed for mission planning, post analysis, and in-situ performance assessment. The meteorological instrument used in conjunction with a radio frequency and electro-optical propagation prediction tactical decision aid tool would give military platforms, in real time, the ability to make assessments on communication systems propagation ranges, radar detection and vulnerability ranges, satellite communications vulnerability, laser range finder performance, and imaging system performance predictions. Raman lidar has been shown to be capable of measuring the required atmospheric parameters needed to profile the atmospheric environment. The atmospheric profile could then be used as input to a tactical decision aid tool to make propagation predictions.

  11. Overview of the Frontal Air-Sea Interaction Experiment (FASINEX) - A study of air-sea interaction in a region of strong oceanic gradients

    NASA Technical Reports Server (NTRS)

    Weller, Robert A.

    1991-01-01

    From 1984 to 1986 the cooperative Frontal Air-Sea Interaction Experiment (FASINEX) was conducted in the subtropical convergence zone southwest of Bermuda. The overall objective of the experiment was to study air-sea interaction on 1- to 100-km horizontal scales in a region of the open ocean characterized by strong horizontal gradients in upper ocean and sea surface properties. Ocean fronts provided both large spatial gradients in sea surface temperature and strong jetlike flows in the upper ocean. The motivation for and detailed objectives of FASINEX are reviewed. Then the components of the field program are summarized. Finally, selected results are presented in order to provide an overview of the outcome of FASINEX.

  12. Infrared propagation in the air-sea boundary layer

    NASA Astrophysics Data System (ADS)

    Larsen, R.; Preedy, K. A.; Drake, G.

    1990-03-01

    Over the oceans and other large bodies of water the structure of the lowest layers of the atmosphere is often strongly modified by evaporation of water vapor from the water surface. At radio wavelengths this layer will usually be strongly refracting or ducting, and the layer is commonly known as the evaporation duct. However, the refractive index of air at infrared wavelengths differs from that at radio wavelengths, and the effects of the marine boundary layer on the propagation of infrared radiation are examined. Meteorological models of the air-sea boundary layer are used to compute vertical profiles of temperature and water-vapor pressure. From these are derived profiles of atmospheric refractive index at radio wavelengths and at infrared wavelengths in the window regions of low absorption. For duct propagation to occur it is necessary that the refractivity of air decreases rapidly with increasing height above the surface. At radio wavelengths this usually occurs when there is a strong lapse of water vapor pressure with increasing height. By contrast, at infrared wavelengths the refractive index is almost independent of water vapor pressure, and it is found that an infrared duct is formed only when there is a temperature inversion.

  13. Symmetric scaling properties in global surface air temperature anomalies

    NASA Astrophysics Data System (ADS)

    Varotsos, Costas A.; Efstathiou, Maria N.

    2015-08-01

    We have recently suggested "long-term memory" or internal long-range correlation within the time-series of land-surface air temperature (LSAT) anomalies in both hemispheres. For example, an increasing trend in the LSAT anomalies is followed by another one at a different time in a power-law fashion. However, our previous research was mainly focused on the overall long-term persistence, while in the present study, the upward and downward scaling dynamics of the LSAT anomalies are analysed, separately. Our results show that no significant fluctuation differences were found between the increments and decrements in LSAT anomalies, over the whole Earth and over each hemisphere, individually. On the contrary, the combination of land-surface air and sea-surface water temperature anomalies seemed to cause a departure from symmetry and the increments in the land and sea surface temperature anomalies appear to be more persistent than the decrements.

  14. An empirically derived inorganic sea spray source function incorporating sea surface temperature

    NASA Astrophysics Data System (ADS)

    Salter, M. E.; Zieger, P.; Acosta Navarro, J. C.; Grythe, H.; Kirkevåg, A.; Rosati, B.; Riipinen, I.; Nilsson, E. D.

    2015-10-01

    We have developed an inorganic sea spray source function that is based upon state-of-the-art measurements of sea spray aerosol production using a temperature-controlled plunging jet sea spray aerosol chamber. The size-resolved particle production was measured between 0.01 and 10 μm dry diameter. Particle production decreased non-linearly with increasing seawater temperature (between -1 and 30 °C) similar to previous findings. In addition, we observed that the particle effective radius, as well as the particle surface, particle volume and particle mass, increased with increasing seawater temperature due to increased production of particles with dry diameters greater than 1 μm. By combining these measurements with the volume of air entrained by the plunging jet we have determined the size-resolved particle flux as a function of air entrainment. Through the use of existing parameterisations of air entrainment as a function of wind speed, we were subsequently able to scale our laboratory measurements of particle production to wind speed. By scaling in this way we avoid some of the difficulties associated with defining the "white area" of the laboratory whitecap - a contentious issue when relating laboratory measurements of particle production to oceanic whitecaps using the more frequently applied whitecap method. The here-derived inorganic sea spray source function was implemented in a Lagrangian particle dispersion model (FLEXPART - FLEXible PARTicle dispersion model). An estimated annual global flux of inorganic sea spray aerosol of 5.9 ± 0.2 Pg yr-1 was derived that is close to the median of estimates from the same model using a wide range of existing sea spray source functions. When using the source function derived here, the model also showed good skill in predicting measurements of Na+ concentration at a number of field sites further underlining the validity of our source function. In a final step, the sensitivity of a large-scale model (NorESM - the

  15. Crowdsourcing urban air temperatures from smartphone battery temperatures

    NASA Astrophysics Data System (ADS)

    Overeem, Aart; Robinson, James C. R.; Leijnse, Hidde; Steeneveld, Gert-Jan; Horn, Berthold K. P.; Uijlenhoet, Remko

    2014-05-01

    Accurate air temperature observations in urban areas are important for meteorology and energy demand planning. They are indispensable to study the urban heat island effect and the adverse effects of high temperatures on human health. However, the availability of temperature observations in cities is often limited. Here we show that relatively accurate air temperature information for the urban canopy layer can be obtained from an alternative, nowadays omnipresent source: smartphones. In this study, battery temperatures were collected by an Android application for smartphones. It has been shown that a straightforward heat transfer model can be employed to estimate daily mean air temperatures from smartphone battery temperatures for eight major cities around the world. The results demonstrate the enormous potential of this crowdsourcing application for real-time temperature monitoring in densely populated areas. Battery temperature data were collected by users of an Android application for cell phones (opensignal.com). The application automatically sends battery temperature data to a server for storage. In this study, battery temperatures are averaged in space and time to obtain daily averaged battery temperatures for each city separately. A regression model, which can be related to a physical model, is employed to retrieve daily air temperatures from battery temperatures. The model is calibrated with observed air temperatures from a meteorological station of an airport located in or near the city. Time series of air temperatures are obtained for each city for a period of several months, where 50% of the data is for independent verification. The methodology has been applied to Buenos Aires, London, Los Angeles, Paris, Mexico City, Moscow, Rome, and Sao Paulo. The evolution of the retrieved air temperatures often correspond well with the observed ones. The mean absolute error of daily air temperatures is less than 2 degrees Celsius, and the bias is within 1 degree

  16. Future Arctic sea ice loss reduces severity of cold air outbreaks in midlatitudes

    NASA Astrophysics Data System (ADS)

    Ayarzagüena, Blanca; Screen, James A.

    2016-03-01

    The effects of Arctic sea ice loss on cold air outbreaks (CAOs) in midlatitudes remain unclear. Previous studies have defined CAOs relative to the present-day climate, but changes in CAOs, defined in such a way, may reflect changes in mean climate and not in weather variability, and society is more sensitive to the latter. Here we revisit this topic but applying changing temperature thresholds relating to climate conditions of the time. CAOs do not change in frequency or duration in response to projected sea ice loss. However, they become less severe, mainly due to advection of warmed polar air, since the dynamics associated with the occurrence of CAOs are largely not affected. CAOs weaken even in midlatitude regions where the winter mean temperature decreases in response to Arctic sea ice loss. These results are robustly simulated by two atmospheric models prescribed with differing future sea ice states and in transient runs where external forcings are included.

  17. Observational Studies of Parameters Influencing Air-sea Gas Exchange

    NASA Astrophysics Data System (ADS)

    Schimpf, U.; Frew, N. M.; Bock, E. J.; Hara, T.; Garbe, C. S.; Jaehne, B.

    A physically-based modeling of the air-sea gas transfer that can be used to predict the gas transfer rates with sufficient accuracy as a function of micrometeorological parameters is still lacking. State of the art are still simple gas transfer rate/wind speed relationships. Previous measurements from Coastal Ocean Experiment in the Atlantic revealed positive correlations between mean square slope, near surface turbulent dis- sipation, and wind stress. It also demonstrated a strong negative correlation between mean square slope and the fluorescence of surface-enriched colored dissolved organic matter. Using heat as a proxy tracer for gases the exchange process at the air/water interface and the micro turbulence at the water surface can be investigated. The anal- ysis of infrared image sequences allow the determination of the net heat flux at the ocean surface, the temperature gradient across the air/sea interface and thus the heat transfer velocity and gas transfer velocity respectively. Laboratory studies were carried out in the new Heidelberg wind-wave facility AELOTRON. Direct measurements of the Schmidt number exponent were done in conjunction with classical mass balance methods to estimate the transfer velocity. The laboratory results allowed to validate the basic assumptions of the so called controlled flux technique by applying differ- ent tracers for the gas exchange in a large Schmidt number regime. Thus a modeling of the Schmidt number exponent is able to fill the gap between laboratory and field measurements field. Both, the results from the laboratory and the field measurements should be able to give a further understanding of the mechanisms controlling the trans- port processes across the aqueous boundary layer and to relate the forcing functions to parameters measured by remote sensing.

  18. Antarctic sea ice and temperature variations

    SciTech Connect

    Walsh, J.E.; Zwally, H.J.; Weatherly, J.W.

    1992-03-01

    Monthly antarctic station temperatures are used in conjunction with grids of sea ice coverage in order to evaluate temporal trends and the strength of associations between the two variables at lags of up to several seasons. The trends of temperature are predominantly positive in winter and summer, but predominantly negative in spring. The spatially aggregated trend of temperature is small but positive, while the corresponding trend of ice coverage is small but negative. Cross-correlations between concurrent anomalies of the two variables are negative over most of the continent and are strongest over the Antarctic Peninsula, especially in winter. In regions other than the Antarctic Peninsula, lag correlations between seasonal anomalies are generally stronger with ice lagging the summer temperatures and with ice leading the winter temperatures.

  19. Bayesian Hierarchical Air-Sea Interaction Modeling: Application to the Labrador Sea

    NASA Technical Reports Server (NTRS)

    Niiler, Pearn P.

    2002-01-01

    The objectives are to: 1) Organize data from 26 MINIMET drifters in the Labrador Sea, including sensor calibration and error checking of ARGOS transmissions. 2) Produce wind direction, barometer, and sea surface temperature time series. In addition, provide data from historical file of 150 SHARP drifters in the Labrador Sea. 3) Work with data interpretation and data-modeling assimilation issues.

  20. Air-sea transfer of gas phase controlled compounds

    NASA Astrophysics Data System (ADS)

    Yang, M.; Bell, T. G.; Blomquist, B. W.; Fairall, C. W.; Brooks, I. M.; Nightingale, P. D.

    2016-05-01

    Gases in the atmosphere/ocean have solubility that spans several orders of magnitude. Resistance in the molecular sublayer on the waterside limits the air-sea exchange of sparingly soluble gases such as SF6 and CO2. In contrast, both aerodynamic and molecular diffusive resistances on the airside limit the exchange of highly soluble gases (as well as heat). Here we present direct measurements of air-sea methanol and acetone transfer from two open cruises: the Atlantic Meridional Transect in 2012 and the High Wind Gas Exchange Study in 2013. The transfer of the highly soluble methanol is essentially completely airside controlled, while the less soluble acetone is subject to both airside and waterside resistances. Both compounds were measured concurrently using a proton-transfer-reaction mass spectrometer, with their fluxes quantified by the eddy covariance method. Up to a wind speed of 15 m s-1, observed air-sea transfer velocities of these two gases are largely consistent with the expected near linear wind speed dependence. Measured acetone transfer velocity is ∼30% lower than that of methanol, which is primarily due to the lower solubility of acetone. From this difference we estimate the “zero bubble” waterside transfer velocity, which agrees fairly well with interfacial gas transfer velocities predicted by the COARE model. At wind speeds above 15 m s-1, the transfer velocities of both compounds are lower than expected in the mean. Air-sea transfer of sensible heat (also airside controlled) also appears to be reduced at wind speeds over 20 m s-1. During these conditions, large waves and abundant whitecaps generate large amounts of sea spray, which is predicted to alter heat transfer and could also affect the air-sea exchange of soluble trace gases. We make an order of magnitude estimate for the impacts of sea spray on air-sea methanol transfer.

  1. Biopolymers form a gelatinous microlayer at the air-sea interface when Arctic sea ice melts

    NASA Astrophysics Data System (ADS)

    Galgani, Luisa; Piontek, Judith; Engel, Anja

    2016-07-01

    The interface layer between ocean and atmosphere is only a couple of micrometers thick but plays a critical role in climate relevant processes, including the air-sea exchange of gas and heat and the emission of primary organic aerosols (POA). Recent findings suggest that low-level cloud formation above the Arctic Ocean may be linked to organic polymers produced by marine microorganisms. Sea ice harbors high amounts of polymeric substances that are produced by cells growing within the sea-ice brine. Here, we report from a research cruise to the central Arctic Ocean in 2012. Our study shows that microbial polymers accumulate at the air-sea interface when the sea ice melts. Proteinaceous compounds represented the major fraction of polymers supporting the formation of a gelatinous interface microlayer and providing a hitherto unrecognized potential source of marine POA. Our study indicates a novel link between sea ice-ocean and atmosphere that may be sensitive to climate change.

  2. Variability patterns of the general circulation and sea water temperature in the North Sea

    NASA Astrophysics Data System (ADS)

    Mathis, M.; Elizalde, A.; Mikolajewicz, U.; Pohlmann, T.

    2015-06-01

    This study investigates patterns of spatio-temporal variability in the North Sea and their major driving mechanisms. Leading variability modes of the general circulation and sea water temperature are extracted from model results by means of Empirical Orthogonal Functions (EOF) analysis. The model results originate from an uncoupled simulation with the global ocean model MPIOM, forced with ERA40 reanalysis data at the air-sea interface. For this regional model study, MPIOM has been run with a stretched grid configuration enabling higher horizontal resolution in the Northwest European Shelf and North Atlantic ocean. The analysis is applied to interannual variabilities of winter and summer separately. The results indicate that on seasonal scales the leading variability mode of the general circulation affects the entire North Sea, accompanied by significant inflow anomalies through the Fair-Isle Passage. Correlations of the corresponding Principal Component (PC) with wind density functions reveal the circulation anomalies to coincide with westerly and south-westerly wind anomalies. The second mode describes circulation anomalies along the Norwegian Trench and English Channel, which correlate with north-westerly wind anomalies caused by variations in large-scale atmospheric pressure areas centered over the British Isles. For sea water temperature, distinct variability patterns are induced by variable surface heat fluxes, vertical mixing, and variable advective heat fluxes. The first mode of both the general circulation and water temperature in winter mainly represents the response to atmospheric variations in the North Atlantic Oscillation (NAO). However, the higher modes account for such variabilities that cannot be explained by the NAO. As a consequence of the integrated effects of the different variability modes on the circulation system and heat content, local correlations of the NAO with volume transports and water temperature are weakened in the regions of

  3. Developments in Airborne Oceanography and Air-Sea Interaction

    NASA Astrophysics Data System (ADS)

    Melville, W. K.

    2014-12-01

    , just as aircraft carriers "project force". Now we can measure winds, waves, temperatures, currents, radiative transfer, images and air-sea fluxes from aircraft over the ocean.I will review some of the history of airborne oceanography and present examples of how it can extend our knowledge and understanding of air-sea interaction.

  4. Diagnosing Air-Sea Interactions on Intraseasonal Timescales

    NASA Astrophysics Data System (ADS)

    DeMott, C. A.

    2014-12-01

    What is the role of ocean coupling in the Madden Julian Oscillation (MJO)? Consensus thinking holds that the essential physics of the MJO involve interactions between convection, atmospheric wave dynamics, and boundary layer and free troposphere moisture. However, many modeling studies demonstrate improved MJO simulation when an atmosphere-only general circulation model (AGCM) is coupled to an ocean model, so feedbacks from the ocean are probably not negligible. Assessing the importance and processes of these feedbacks is challenging for at least two reasons. First, observations of the MJO only sample the fully coupled ocean-atmosphere system; there is no "uncoupled" MJO in nature. Second, the practice of analyzing the MJO in uncoupled and coupled GCMs (CGCMs) involves using imperfect tools to study the problem. Although MJO simulation is improving in many models, shortcomings remain in both AGCMs and CGCMs, making it difficult to determine if changes brought about through coupling reflect critical air-sea interactions or are simply part of the collective idiosyncracies of a given model. For the atmosphere, ocean feedbacks from intraseasonal sea surface temperature (SST) variations are communicated through their effects on surface fluxes of heat and moisture. This presentation suggests a set of analysis tools for diagnosing the impact of an interactive ocean on surface latent and sensible heat fluxes, including their mean, variance, spectral characteristics, and phasing with respect to wind, SST, and MJO convection. The diagnostics are demonstrated with application to several CMIP5 models, and reveal a variety of responses to coupled ocean feedbacks.

  5. Air-sea coupling in the Hawaiian Archipelago

    NASA Astrophysics Data System (ADS)

    Souza, J. M.; Powell, B.; Mattheus, D.

    2014-12-01

    A coupled numerical model is used to investigate the ocean-atmosphere interaction in the lee of the Hawaiian archipelago. The wind curl generated by the island blocking of the trade winds is known to give rise to ocean eddies; however, the impact of the sea surface temperature (SST) and velocity fronts associated with these eddies on the atmosphere is less understood. The main coupling mechanisms are: (i) changes in the near-surface stability and surface stress, (ii) vertical transfer of momentum from higher atmospheric levels to the ocean surface due to an increase of the turbulence in the boundary layer, (iii) secondary circulations associated with perturbations in the surface atmospheric pressure over the SST fronts, and (iv) the impact of the oceanic eddy currents on the net momentum transferred between the atmosphere and the ocean. To assess the relative contribution from each process, a coupled simulation between the Regional Ocean Modeling System (ROMS) and the Weather Research and Forecasting (WRF) models is conducted for the main Hawaiian Islands. The impact of the coupling, the perturbation of the mean wind pattern, and the different spatial scales involved in the air-sea exchanges of momentum and heat are explored.

  6. Unstable Air-Sea Interaction in the Extratropical North Atlantic

    NASA Technical Reports Server (NTRS)

    Hakkinen, Sirpa

    1999-01-01

    The possibility of coupled modes in the extratropical North Atlantic has fascinated the climate community since 1960's. A significant aspect of such modes is an unstable air-sea interaction, also called positive feedback, where disturbances between the atmosphere and ocean grow unbound. If a delayed response exists before the negative feedback takes effect, an oscillatory behaviour will develop. Here we explore the relationship between heat flux (positive upward) and sea surface temperature (SST). Positive feedback is characterized by a cross-correlation between the two where correlation maintains a negative sign whether SST or heat flux leads. We use model results and observations to argue that in the North Atlantic there exist regions with positive feedback. The two main locations coincide with the well-known north-south SST dipole where anomalies of opposite sign occupy areas east of Florida and north-east of Newfoundland. We show that oceanic dynamics, wave propagation and advection, give rise to oceanic anomalies in these regions. Subsequently these anomalies are amplified by atmosphere- ocean interaction: thus a positive feedback.

  7. Spatial and temporal variability of satellite-derived sea surface temperature in the Barents Sea

    NASA Astrophysics Data System (ADS)

    Stramska, Malgorzata; Jakowczyk, Mateusz

    2016-04-01

    The Barents Sea (BS) is an important region for studying climate change. This sea is located on the main pathway of the heat transported from low to high latitudes. Since oceanic conditions in the BS may influence vast areas of the Arctic Ocean, it is important to continue to monitor this region and to analyze the available oceanographic data sets. One of the important quantities that can be used to track climate change is the sea surface temperature (SST). In this study we have analyzed the 32-years (1982-2013) NOAA Optimum Interpolation SST Version 2 data for the BS. Our results indicate that the regionally averaged SST trend in the BS (~0.03 oC/year) is greater than the global trend. This trend varies spatially with the lowest values north from 76°N and the highest values (~0.06oC/year) in proximity of Svalbard and in coastal regions near the White Sea. The SST and 2-m air temperature (AT) trends are high in winter months in the open Barents Sea region located west from Novaya Zemlya. Such trends can be linked to a significant retreat of sea ice in this area in recent years. In this paper we also documented spatial patterns in the annual cycle of SST in the BS. We have shown that the interannual variability of SST is similar in different regions of the BS and well correlated with the interannual patterns in AT variability. This work was funded by the Norway Grants (NCBR contract No. 201985, project NORDFLUX). Partial support for MS comes from the Institute of Oceanology (IO PAN).

  8. Sea surface temperature and torrential rains in the Valencia region: modelling the role of recharge areas

    NASA Astrophysics Data System (ADS)

    Pastor, F.; Valiente, J. A.; Estrela, M. J.

    2015-02-01

    Heavy rain events are frequently recorded in the Western Mediterranean causing economic losses and even human casualties. The Western Mediterranean is a deep and almost closed sea surrounded by high mountain ranges and with little exchange of water with the Atlantic ocean. A main factor in the development of torrential rains are ocean-atmosphere exchanges of heat and moisture that can potentially destabilize air masses travelling over the sea. The study of air mass trajectories previous to the rain event permits the identification of sea areas that could probably contribute to the development or intensification of rainfall. From a previous Mediterranean sea surface temperature climatology, its spatio-temporal distribution patterns have been studied showing two main distribution modes in winter and summer and transitional regimes in spring and autumn. Hence, three heavy precipitation events, for such winter and summer sea temperature regimes and for fall transition, affecting the Valencia region have been selected to study the effect of sea surface temperature in torrential rains. Simulations with perturbed sea surface temperature in different areas along the air mass path were run to compare results with unperturbed simulation. The variation of sea surface temperature in certain areas caused significant changes in model accumulated values and its spatial distribution. Therefore, the existence of recharge areas where air-sea interaction favors the development of torrential rainfall in Valencia region has been shown. This methodology could be extended to the whole Mediterranean basin to look for such potential recharge areas. The identification of sea areas that contribute to the development or intensification of heavy rain events in the Mediterranean countries could be a useful prognosis and/or monitoring tool.

  9. Sea surface temperature and torrential rains in the Valencia region: modelling the role of recharge areas

    NASA Astrophysics Data System (ADS)

    Pastor, F.; Valiente, J. A.; Estrela, M. J.

    2015-07-01

    Heavy rain events are frequently recorded in the Western Mediterranean causing economic losses and even human casualties. The Western Mediterranean is a deep and almost closed sea surrounded by high mountain ranges and with little exchange of water with the Atlantic ocean. A main factor in the development of torrential rains is ocean-atmosphere exchanges of heat and moisture that can potentially destabilize air masses travelling over the sea. The study of air mass trajectories previous to the rain event permits the identification of sea areas that could probably contribute to the development or intensification of rainfall. From a previous Mediterranean sea surface temperature climatology, its spatio-temporal distribution patterns have been studied showing two main distribution modes in winter and summer and transitional regimes in spring and autumn. Hence, three heavy precipitation events, for such winter and summer sea temperature regimes and for fall transition, affecting the Valencia region have been selected to study the effect of sea surface temperature in torrential rains. Simulations with perturbed sea surface temperature in different areas along the air mass path were run to compare results with unperturbed simulation. The variation of sea surface temperature in certain areas caused significant changes in model accumulated values and its spatial distribution. Therefore, the existence of areas that at a greater extent favour air-sea interaction leading to the development of torrential rainfall in the Valencia region has been shown. This methodology could be extended to the whole Mediterranean basin to look for such potential recharge areas. The identification of sea areas that contribute to the development or intensification of heavy rain events in the Mediterranean countries could be a useful prognosis and/or monitoring tool.

  10. Satellite observations of air-sea interaction over the Kuroshio

    NASA Astrophysics Data System (ADS)

    Xie, S.; Nonaka, M.; Hafner, J.; Liu, W. T.

    2002-12-01

    Satellite microwave measurements are analyzed, revealing robust co-variability in sea surface temperature (SST) and wind speed over the Kuroshio and its Extension (KE). Ocean hydrodynamic instabilities cause the KE to meander and result into large SST variations. Increased (reduced) wind speeds are found to be associated with warm (cold) SST anomalies. This positive SST-wind correlation in KE is confirmed by in-situ buoy measurements and is consistent with a vertical shear adjustment mechanism. Namely, an increase in SST reduces the static stability of the near-surface atmosphere, intensifying the vertical turbulence mixing and bringing fast-moving air from aloft to the sea surface. South of Japan, the Kuroshio is known to vary between nearshore and offshore paths. Both paths seem semi-permanent and can persist months to years. As the Kuroshio shifts its path, coherent wind changes are detected. In particular, winds are high south of Tokyo when the Kuroshio takes the nearshore path while they are greatly reduced when this warm current leaves the coast in the offshore path. Further upstream in the East China Sea, on the warmer flank of the Kuroshio Front, there are a zone of high wind speed and a band of raining cloud due to the region's unstable atmospheric stratification near the surface. Surface wind convergence is roughly collocated with the Kuroshio Current. By increasing the baroclinicity and condensational heating, the Kuroshio Front aids the growth of the so-called Taiwan cyclone, an important winter weather phenomenon for Japan. The positive SST-wind correlation over the strong Kuroshio Current and its extension is opposite to the negative one often observed in regions of weak currents such as south of the Aleutian low that is considered to be indicative of atmosphere-to-ocean forcing.

  11. Crowdsourcing urban air temperatures from smartphone battery temperatures

    NASA Astrophysics Data System (ADS)

    Overeem, A.; Robinson, J. C. R.; Leijnse, H.; Steeneveld, G. J.; Horn, B. K. P.; Uijlenhoet, R.

    2013-08-01

    Accurate air temperature observations in urban areas are important for meteorology and energy demand planning. They are indispensable to study the urban heat island effect and the adverse effects of high temperatures on human health. However, the availability of temperature observations in cities is often limited. Here we show that relatively accurate air temperature information for the urban canopy layer can be obtained from an alternative, nowadays omnipresent source: smartphones. In this study, battery temperatures were collected by an Android application for smartphones. A straightforward heat transfer model is employed to estimate daily mean air temperatures from smartphone battery temperatures for eight major cities around the world. The results demonstrate the enormous potential of this crowdsourcing application for real-time temperature monitoring in densely populated areas.

  12. Controlled-Temperature Hot-Air Gun

    NASA Technical Reports Server (NTRS)

    Munoz, M. C.

    1986-01-01

    Materials that find applications in wind tunnels first tested in laboratory. Hot-Air Gun differs from commercial units in that flow rate and temperature monitored and controlled. With typical compressed-airsupply pressure of 25 to 38 psi (170 to 260 kPa), flow rate and maximum temperature are 34 stdft3/min (0.96 stdm3/min) and 1,090 degrees F (590 degrees C), respectively. Resembling elaborate but carefully regulated hot-air gun, setup used to apply blasts of air temperatures above 1,500 degrees F (815 degrees C) to test specimens.

  13. Climatology of upper air temperature in the Eastern Mediterranean region

    NASA Astrophysics Data System (ADS)

    Philandras, C. M.; Nastos, P. T.; Kapsomenakis, I. N.; Repapis, C. C.

    2015-01-01

    The goal of this study is to contribute to the climatology of upper air temperature in the Mediterranean region, during the period 1965-2011. For this purpose, both radiosonde recordings and gridded reanalysis datasets of upper air temperature from National Center for Environmental Prediction-National Center for Atmospheric Research (NCEP-NCAR) were used for seven barometric levels at 850 hPa, 700 hPa, 500 hPa, 300 hPa, 200 hPa, 150 hPa and 100 hPa. Trends and variability of upper air temperature were analyzed on annual and seasonal basis. Further, the impact of atmospheric circulation, by means of correlation between upper air temperature at different barometric levels and specific climatic indices such as Mediterranean Oscillation Index (MOI), North Sea Caspian Pattern Index (NCPI) and North Atlantic Oscillation Index (NAOI), was also quantified. Our findings have given evidence that air temperature is increasing at a higher rate in lower/middle troposphere against upper, and this is very likely due to increasing greenhouse gas concentrations.

  14. Air-Sea Interaction Measurements from R/P FLIP

    NASA Astrophysics Data System (ADS)

    Friehe, C. A.

    2002-12-01

    Soon after its inception, R/P FLIP was used to study the interaction of the atmosphere and ocean due to its unique stability and low flow distortion. A number of campaigns have been conducted to measure the surface fluxes of heat, water vapor and horizontal momentum of the wind with instrumentation as used over land, supported by the Office of Naval Research and the National Science Foundation. The size of FLIP allows for simultaneous ocean wave and mixed-layer measurements as well. Air-sea interaction was a prime component of BOMEX in 1968, where FLIP transited the Panama Canal. The methods used were similar to the over-land "Kansas" experiment of AFCRL in 1968. BOMEX was followed by many experiments in the north Pacific off San Diego, northern California, and Hawaii. Diverse results from FLIP include identification of the mechanism that causes erroneous fluctuating temperature measurements in the salt-aerosol-laden marine atmosphere, the role of humidity on optical refractive index fluctuations, and identification of Miles' critical layer in the air flow over waves.

  15. Sea Surface Temperature and Vegetation Index

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This is a composite MODIS image showing the 'green wave' of spring in North America and sea surface temperature in the ocean, collected over an 8-day period during the first week in April 2000. On land, the darker green pixels show where the most green foliage is being produced due to photosynthetic activity. Yellows on land show where there is little or no productivity and red is a boundary zone. In the ocean, orange and yellows show warmer waters and blues show colder values.

  16. A global monthly sea surface temperature climatology

    SciTech Connect

    Shea, D.J.; Trenberth, K.E.; Reynolds, R.W. NOAA, Climate Analysis Center, Washington, DC )

    1992-09-01

    The paper presents a new global 2 deg x 2 deg monthly sea surface temperature (SST) climatology, referred here to as the Shea-Trenberth-Reynolds (STR) climatology, which was derived by modifying a 1950-1979-based SST climatology from the Climate Analysis Center (CAC), by using data from the Comprehensive Ocean-Atmosphere Data Set to improve the SST estimates in the regions of the Kuroshio and the Gulf Stream. A comparison of the STR climatology with the Alexander and Mobley SST climatology showed that the STR climatology is warmer in the Northern Hemisphere, and colder poleward of 45 deg S. 22 refs.

  17. Air separation with temperature and pressure swing

    DOEpatents

    Cassano, Anthony A.

    1986-01-01

    A chemical absorbent air separation process is set forth which uses a temperature swing absorption-desorption cycle in combination with a pressure swing wherein the pressure is elevated in the desorption stage of the process.

  18. Air-Sea Interaction Measurements from the Controlled Towed Vehicle

    NASA Astrophysics Data System (ADS)

    Khelif, D.; Bluth, R. T.; Jonsson, H.; Barge, J.

    2014-12-01

    The Controlled Towed Vehicle (CTV) uses improved towed drone technology to actively maintain via a radar altimeter and controllable wing a user-set height that can be as low as the canonical reference height of 10 m above the sea surface. After take-off, the drone is released from the tow aircraft on a ~700-m stainless steel cable. We have instrumented the 0.23 m diameter and 2.13 m long drone with high fidelity instruments to measure the means and turbulent fluctuations of 3-D wind vector, temperature, humidity, pressure, CO2 and IR sea surface temperature. Data are recorded internally at 40 Hz and simultaneously transmitted to the tow aircraft via dedicated wireless Ethernet link. The CTV accommodates 40 kg of instrument payload and provides it with 250 W of continuous power through a ram air propeller-driven generator. Therefore its endurance is only limited by that of the tow aircraft.We will discuss the CTV development, the engineering challenges and solutions that have been successfully implemented to overcome them. We present results from recent flights as low as 9 m over the coastal ocean and comparisons of profiles and turbulent fluxes from the CTV and the tow aircraft. Manned aircraft operation at low-level boundary-layer flights is very limited. Dropsondes and UAS (Unmanned Aerial Systems) and UAS are alternates for measurements near the ocean surface. However, dropsondes have limited sensor capability and do not measure fluxes, and most present UAS vehicles do not have the payload and power capacity nor the low-flying ability in high winds over the oceans. The CTV therefore, fills a needed gap between the dropsondes, in situ aircraft, and UAS. The payload, capacity and power of the CTV makes it suitable for a variety of atmospheric research measurements. Other sensors to measure aerosol, chemistry, radiation, etc., could be readily accommodated in the CTV.

  19. The SOLAS air-sea gas exchange experiment (SAGE) 2004

    NASA Astrophysics Data System (ADS)

    Harvey, Mike J.; Law, Cliff S.; Smith, Murray J.; Hall, Julie A.; Abraham, Edward R.; Stevens, Craig L.; Hadfield, Mark G.; Ho, David T.; Ward, Brian; Archer, Stephen D.; Cainey, Jill M.; Currie, Kim I.; Devries, Dawn; Ellwood, Michael J.; Hill, Peter; Jones, Graham B.; Katz, Dave; Kuparinen, Jorma; Macaskill, Burns; Main, William; Marriner, Andrew; McGregor, John; McNeil, Craig; Minnett, Peter J.; Nodder, Scott D.; Peloquin, Jill; Pickmere, Stuart; Pinkerton, Matthew H.; Safi, Karl A.; Thompson, Rona; Walkington, Matthew; Wright, Simon W.; Ziolkowski, Lori A.

    2011-03-01

    The SOLAS air-sea gas exchange experiment (SAGE) was a multiple-objective study investigating gas-transfer processes and the influence of iron fertilisation on biologically driven gas exchange in high-nitrate low-silicic acid low-chlorophyll (HNLSiLC) Sub-Antarctic waters characteristic of the expansive subpolar zone of the southern oceans. This paper provides a general introduction and summary of the main experimental findings. The release site was selected from a pre-voyage desktop study of environmental parameters to be in the south-west Bounty Trough (46.5°S 172.5°E) to the south-east of New Zealand and the experiment was conducted between mid-March and mid-April 2004. In common with other mesoscale iron addition experiments (FeAX's), SAGE was designed as a Lagrangian study, quantifying key biological and physical drivers influencing the air-sea gas exchange processes of CO 2, DMS and other biogenic gases associated with an iron-induced phytoplankton bloom. A dual tracer SF 6/ 3He release enabled quantification of both the lateral evolution of a labelled volume (patch) of ocean and the air-sea tracer exchange at tenths of kilometer scale, in conjunction with the iron fertilisation. Estimates from the dual-tracer experiment found a quadratic dependency of the gas exchange coefficient on windspeed that is widely applicable and describe air-sea gas exchange in strong wind regimes. Within the patch, local and micrometeorological gas exchange process studies (100 m scale) and physical variables such as near-surface turbulence, temperature microstructure at the interface, wave properties and windspeed were quantified to further assist the development of gas exchange models for high-wind environments. There was a significant increase in the photosynthetic competence ( Fv/ Fm) of resident phytoplankton within the first day following iron addition, but in contrast to other FeAX's, rates of net primary production and column-integrated chlorophyll a concentrations had

  20. Effect of air-sea coupling on the frequency distribution of intense tropical cyclones over the northwestern Pacific

    NASA Astrophysics Data System (ADS)

    Ogata, Tomomichi; Mizuta, Ryo; Adachi, Yukimasa; Murakami, Hiroyuki; Ose, Tomoaki

    2015-12-01

    Effect of air-sea coupling on the frequency distribution of intense tropical cyclones (TCs) over the northwestern Pacific (NWP) region is investigated using an atmosphere and ocean coupled general circulation model (AOGCM). Monthly varying flux adjustment enables AOGCM to simulate both subseasonal air-sea interaction and realistic seasonal to interannual sea surface temperature (SST) variability. The maximum of intense TC distribution around 20-30°N in the AGCM shifts equatorward in the AOGCM due to the air-sea coupling. Hence, AOGCM reduces northward intense TC distribution bias seen in AGCM. Over the NWP, AOGCM-simulated SST variability is large around 20-30°N where the warm mixed layer becomes shallower rapidly. Active entrainment from subsurface water over this region causes stronger SST cooling, and hence, TC intensity decreases. These results suggest that air-sea coupling characterized by subsurface oceanic condition causes more realistic distribution of intense TCs over the NWP.

  1. Crowdsourcing urban air temperature measurements using smartphones

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2013-10-01

    Crowdsourced data from cell phone battery temperature sensors could be used to contribute to improved real-time, high-resolution air temperature estimates in urban areas, a new study shows. Temperature observations in cities are in some cases currently limited to a few weather stations, but there are millions of smartphone users in many cities. The batteries in cell phones have temperature sensors to avoid damage to the phone.

  2. Modern average global sea-surface temperature

    USGS Publications Warehouse

    Schweitzer, Peter N.

    1993-01-01

    The data contained in this data set are derived from the NOAA Advanced Very High Resolution Radiometer Multichannel Sea Surface Temperature data (AVHRR MCSST), which are obtainable from the Distributed Active Archive Center at the Jet Propulsion Laboratory (JPL) in Pasadena, Calif. The JPL tapes contain weekly images of SST from October 1981 through December 1990 in nine regions of the world ocean: North Atlantic, Eastern North Atlantic, South Atlantic, Agulhas, Indian, Southeast Pacific, Southwest Pacific, Northeast Pacific, and Northwest Pacific. This data set represents the results of calculations carried out on the NOAA data and also contains the source code of the programs that made the calculations. The objective was to derive the average sea-surface temperature of each month and week throughout the whole 10-year series, meaning, for example, that data from January of each year would be averaged together. The result is 12 monthly and 52 weekly images for each of the oceanic regions. Averaging the images in this way tends to reduce the number of grid cells that lack valid data and to suppress interannual variability.

  3. Stratospheric Impact of Varying Sea Surface Temperatures

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.; Nielsen, Jon E.; Waugh, Darryn; Pawson, Steven

    2004-01-01

    The Finite-Volume General Circulation Model (FVGCM) has been run in 50 year simulations with the: 1) 1949-1999 Hadley Centre sea surface temperatures (SST), and 2) a fixed annual cycle of SSTs. In this presentation we first show that the 1949-1999 FVGCM simulation produces a very credible stratosphere in comparison to an NCEP/NCAR reanalysis climatology. In particular, the northern hemisphere has numerous major and minor stratospheric warming, while the southern hemisphere has only a few over the 50-year simulation. During the northern hemisphere winter, temperatures are both warmer in the lower stratosphere and the polar vortex is weaker than is found in the mid-winter southern hemisphere. Mean temperature differences in the lower stratosphere are shown to be small (less than 2 K), and planetary wave forcing is found to be very consistent with the climatology. We then will show the differences between our varying SST simulation and the fixed SST simulation in both the dynamics and in two parameterized trace gases (ozone and methane). In general, differences are found to be small, with subtle changes in planetary wave forcing that lead to reduced temperatures in the SH and increased temperatures in the NH.

  4. Nowcasting daily minimum air and grass temperature

    NASA Astrophysics Data System (ADS)

    Savage, M. J.

    2016-02-01

    Site-specific and accurate prediction of daily minimum air and grass temperatures, made available online several hours before their occurrence, would be of significant benefit to several economic sectors and for planning human activities. Site-specific and reasonably accurate nowcasts of daily minimum temperature several hours before its occurrence, using measured sub-hourly temperatures hours earlier in the morning as model inputs, was investigated. Various temperature models were tested for their ability to accurately nowcast daily minimum temperatures 2 or 4 h before sunrise. Temperature datasets used for the model nowcasts included sub-hourly grass and grass-surface (infrared) temperatures from one location in South Africa and air temperature from four subtropical sites varying in altitude (USA and South Africa) and from one site in central sub-Saharan Africa. Nowcast models used employed either exponential or square root functions to describe the rate of nighttime temperature decrease but inverted so as to determine the minimum temperature. The models were also applied in near real-time using an open web-based system to display the nowcasts. Extrapolation algorithms for the site-specific nowcasts were also implemented in a datalogger in an innovative and mathematically consistent manner. Comparison of model 1 (exponential) nowcasts vs measured daily minima air temperatures yielded root mean square errors (RMSEs) <1 °C for the 2-h ahead nowcasts. Model 2 (also exponential), for which a constant model coefficient ( b = 2.2) was used, was usually slightly less accurate but still with RMSEs <1 °C. Use of model 3 (square root) yielded increased RMSEs for the 2-h ahead comparisons between nowcasted and measured daily minima air temperature, increasing to 1.4 °C for some sites. For all sites for all models, the comparisons for the 4-h ahead air temperature nowcasts generally yielded increased RMSEs, <2.1 °C. Comparisons for all model nowcasts of the daily grass

  5. Nowcasting daily minimum air and grass temperature.

    PubMed

    Savage, M J

    2016-02-01

    Site-specific and accurate prediction of daily minimum air and grass temperatures, made available online several hours before their occurrence, would be of significant benefit to several economic sectors and for planning human activities. Site-specific and reasonably accurate nowcasts of daily minimum temperature several hours before its occurrence, using measured sub-hourly temperatures hours earlier in the morning as model inputs, was investigated. Various temperature models were tested for their ability to accurately nowcast daily minimum temperatures 2 or 4 h before sunrise. Temperature datasets used for the model nowcasts included sub-hourly grass and grass-surface (infrared) temperatures from one location in South Africa and air temperature from four subtropical sites varying in altitude (USA and South Africa) and from one site in central sub-Saharan Africa. Nowcast models used employed either exponential or square root functions to describe the rate of nighttime temperature decrease but inverted so as to determine the minimum temperature. The models were also applied in near real-time using an open web-based system to display the nowcasts. Extrapolation algorithms for the site-specific nowcasts were also implemented in a datalogger in an innovative and mathematically consistent manner. Comparison of model 1 (exponential) nowcasts vs measured daily minima air temperatures yielded root mean square errors (RMSEs) <1 °C for the 2-h ahead nowcasts. Model 2 (also exponential), for which a constant model coefficient (b = 2.2) was used, was usually slightly less accurate but still with RMSEs <1 °C. Use of model 3 (square root) yielded increased RMSEs for the 2-h ahead comparisons between nowcasted and measured daily minima air temperature, increasing to 1.4 °C for some sites. For all sites for all models, the comparisons for the 4-h ahead air temperature nowcasts generally yielded increased RMSEs, <2.1 °C. Comparisons for all model nowcasts of the daily grass

  6. Improving Forecast Skill by Assimilation of AIRS Temperature Soundings

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Reale, Oreste

    2010-01-01

    AIRS was launched on EOS Aqua on May 4, 2002, together with AMSU-A and HSB, to form a next generation polar orbiting infrared and microwave atmospheric sounding system. The primary products of AIRS/AMSU-A are twice daily global fields of atmospheric temperature-humidity profiles, ozone profiles, sea/land surface skin temperature, and cloud related parameters including OLR. The AIRS Version 5 retrieval algorithm, is now being used operationally at the Goddard DISC in the routine generation of geophysical parameters derived from AIRS/AMSU data. A major innovation in Version 5 is the ability to generate case-by-case level-by-level error estimates delta T(p) for retrieved quantities and the use of these error estimates for Quality Control. We conducted a number of data assimilation experiments using the NASA GEOS-5 Data Assimilation System as a step toward finding an optimum balance of spatial coverage and sounding accuracy with regard to improving forecast skill. The model was run at a horizontal resolution of 0.5 deg. latitude X 0.67 deg longitude with 72 vertical levels. These experiments were run during four different seasons, each using a different year. The AIRS temperature profiles were presented to the GEOS-5 analysis as rawinsonde profiles, and the profile error estimates delta (p) were used as the uncertainty for each measurement in the data assimilation process. We compared forecasts analyses generated from the analyses done by assimilation of AIRS temperature profiles with three different sets of thresholds; Standard, Medium, and Tight. Assimilation of Quality Controlled AIRS temperature profiles significantly improve 5-7 day forecast skill compared to that obtained without the benefit of AIRS data in all of the cases studied. In addition, assimilation of Quality Controlled AIRS temperature soundings performs better than assimilation of AIRS observed radiances. Based on the experiments shown, Tight Quality Control of AIRS temperature profile performs best

  7. Sea water temperature variation east of Taiwan

    NASA Astrophysics Data System (ADS)

    Yin, Fuh

    Temperature, wave and wind data over two years off Ho Peng, Shi Ti and Jang Yuan of east Taiwan are analyzed to study their seasonal variations. A model for predicting the mixed layer thickness is developed by use of wave data. The vertical profile of temperature indicates that there are basically three layers; mixed layer, thermocline layer and deep cold layer. The surface mixed layer appears in winter and disappears in summer. While surface water is warmer in summer than in winter, water at a depth of 50 m is warmer in winter than in summer. The seasonal variation in the deep cold layer is weak. The sea surface temperature is generally higher offshore than nearshore. The surface temperature off east Taiwan is almost equal to that in Taiwan Strait in summer, but in winter it is about 4°C warmer off northeast Taiwan than in the northeast of the Taiwan Strait, if compared at the same latitude. This is an effect of the seasonal variation of the Kuroshio. A model is developed for predicting the mixed layer thickness in terms of the input wave energy. The model successfully accounts for the observed features.

  8. Temperature Tunable Air-Gap Etalon Filter

    NASA Technical Reports Server (NTRS)

    Krainak, Michael A.; Stephen, Mark A.; Lunt, David L.

    1998-01-01

    We report on experimental measurements of a temperature tuned air-gap etalon filter. The filter exhibits temperature dependent wavelength tuning of 54 pm/C. It has a nominal center wavelength of 532 nm. The etalon filter has a 27 pm optical bandpass and 600 pm free spectral range (finesse approximately 22). The experimental results are in close agreement with etalon theory.

  9. Air-sea heat exchange, an element of the water cycle

    NASA Technical Reports Server (NTRS)

    Chahine, M. T.

    1984-01-01

    The distribution and variation of water vapor, clouds and precipitation are examined. Principal driving forces for these distributions are energy exchange and evaporation at the air-sea interface, which are also important elements of air-sea interaction studies. The overall aim of air-sea interaction studies is to quantitatively determine mass, momentum and energy fluxes, with the goal of understanding the mechanisms controlling them. The results of general circulation simulations indicate that the atmosphere in mid-latitudes responds to changes in the oceanic surface conditions in the tropics. This correlation reflects the strong interaction between tropical and mid-latitude conditions caused by the transport of heat and momentum from the tropics. Studies of air-sea exchanges involve a large number of physica, chemical and dynamical processes including heat flux, radiation, sea-surface temperature, precipitation, winds and ocean currents. The fluxes of latent heat are studied and the potential use of satellite data in determining them evaluated. Alternative ways of inferring heat fluxes will be considered.

  10. Influence of Land-sea Breeze on Air Quality Over Taiwan Coastal Environment

    NASA Astrophysics Data System (ADS)

    Chang, J. S.; Chiang, C.

    2008-12-01

    Taiwan is is an island nation in western Pacific close to Mainland China. As such Land-sea breeze is a natural processes. Many major cities and industrial developments naturally developed near coastal area. As air quality in urban and industrial centers worsened impact on coastal areas increases. Land-sea breeze naturally plays an important role in transport of pollutants to and from polluted regions to the coastal environment. In this study we analyzed a full year of Taiwan EPA monitored hourly data on O3, NOx, CO, CO2, temperature, wind direction and speed to group and identify time and place with significant land-sea breeze phenomenon. We first compare coastal air quality condition with and without land-sea breeze and then use a 3-D regional-scale transport and chemistry model to provide detailed diagnostic interpretations of the coupling of pollution source regions and coastal areas. From this we can clarify when and how land-sea breeze may play a role in determining coastal air quality. Two different subregions of Taiwan are of interest in this study, Taipei and Kaoshiung environments, in the north and south of Taiwan respectively. Taipei is about 30-50 km away from its impacted coastal area while Kaoshiung is directly at and inland of its coastal shore. For Taipei region daytime upper air pollutants can be transported out to sea and then subside and return to the coastal area at night. But under summer severely polluted condition surface Taipei urban pollutants actually extend beyond the coastal area hence at night the return flow only brings back the same air mass. In contrast, Kaoshiung area is almost always under high pollution status. Its domain of influence always extends far beyond the coastal shore. Therefore, with and without land-sea breeze, coastal pollution remains about the same. We shall present detailed 2-D and 3-D data and station by station analyses in support of these findings.

  11. Satellite Sensed Skin Sea Surface Temperature

    NASA Technical Reports Server (NTRS)

    Donlon, Craig

    1997-01-01

    Quantitative predictions of spatial and temporal changes the global climate rely heavily on the use of computer models. Unfortunately, such models cannot provide the basis for climate prediction because key physical processes are inadequately treated. Consequently, fine tuning procedures are often used to optimize the fit between model output and observational data and the validation of climate models using observations is essential if model based predictions of climate change are to be treated with any degree of confidence. Satellite Sea Surface Temperature (SST) observations provide high spatial and temporal resolution data which is extremely well suited to the initialization, definition of boundary conditions and, validation of climate models. In the case of coupled ocean-atmosphere models, the SST (or more correctly the 'Skin' SST (SSST)) is a fundamental diagnostic variable to consider in the validation process. Daily global SST maps derived from satellite sensors also provide adequate data for the detection of global patterns of change which, unlike any other SST data set, repeatedly extend into the southern hemisphere extra-tropical regions. Such data are essential to the success of the spatial 'fingerprint' technique, which seeks to establish a north-south asymmetry where warming is suppressed in the high latitude Southern Ocean. Some estimates suggest that there is a greater than 80% chance of directly detecting significant change (97.5 % confidence level) after 10-12 years of consistent global observations of mean sea surface temperature. However, these latter statements should be qualified with the assumption that a negligible drift in the observing system exists and that biases between individual instruments required to derive a long term data set are small. Given that current estimates for the magnitude of global warming of 0.015 K yr(sup -1) - 0.025 K yr(sup -1), satellite SST data sets need to be both accurate and stable if such a warming trend is to

  12. A multispectral method of determining sea surface temperatures

    NASA Technical Reports Server (NTRS)

    Shenk, W. E.

    1972-01-01

    A multispectral method for determining sea surface temperatures is discussed. The specifications of the equipment and the atmospheric conditions required for successful multispectral data acquisition are described. Examples of data obtained in the North Atlantic Ocean are presented. The differences between the actual sea surface temperatures and the equivalent blackbody temperatures as determined by a radiometer are plotted.

  13. Air-sea interaction with multiple sensors - Seasat legacy

    NASA Technical Reports Server (NTRS)

    Liu, W. T.; Tang, W.

    2003-01-01

    By flying a number of ocean observing sensors together, Seasat demonstrated potential of not only sensor synergism, but also science synergism, which has illuminated the path of spacebased air-sea interaction studies in more than two decades since its demise.

  14. NASA Wallops Flight Facility Air-Sea Interaction Research Facility

    NASA Technical Reports Server (NTRS)

    Long, Steven R.

    1992-01-01

    This publication serves as an introduction to the Air-Sea Interaction Research Facility at NASA/GSFC/Wallops Flight Facility. The purpose of this publication is to provide background information on the research facility itself, including capabilities, available instrumentation, the types of experiments already done, ongoing experiments, and future plans.

  15. Geomagnetic activity and polar surface air temperature variability

    NASA Astrophysics Data System (ADS)

    Seppälä, A.; Randall, C. E.; Clilverd, M. A.; Rozanov, E.; Rodger, C. J.

    2009-10-01

    Here we use the ERA-40 and ECMWF operational surface level air temperature data sets from 1957 to 2006 to examine polar temperature variations during years with different levels of geomagnetic activity, as defined by the A p index. Previous modeling work has suggested that NO x produced at high latitudes by energetic particle precipitation can eventually lead to detectable changes in surface air temperatures (SATs). We find that during winter months, polar SATs in years with high A p index are different than in years with low A p index; the differences are statistically significant at the 2-sigma level and range up to about ±4.5 K, depending on location. The temperature differences are larger when years with wintertime Sudden Stratospheric Warmings (SSWs) are excluded. We take into account solar irradiance variations, unlike previous analyses of geomagnetic effects in ERA-40 and operational data. Although we cannot conclusively show that the polar SAT patterns are physically linked by geomagnetic activity, we conclude that geomagnetic activity likely plays a role in modulating wintertime surface air temperatures. We tested our SAT results against variation in the Quasi Biennial Oscillation, the El Niño Southern Oscillation and the Southern Annular Mode. The results suggested that these were not driving the observed polar SAT variability. However, significant uncertainty is introduced by the Northern Annular Mode, and we cannot robustly exclude a chance linkage between sea surface temperature variability and geomagnetic activity.

  16. Undulator Hall Air Temperature Fault Scenarios

    SciTech Connect

    Sevilla, J.; Welch, J.; /SLAC

    2010-11-17

    Recent experience indicates that the LCLS undulator segments must not, at any time following tuning, be allowed to change temperature by more than about {+-}2.5 C or the magnetic center will irreversibly shift outside of acceptable tolerances. This vulnerability raises a concern that under fault conditions the ambient temperature in the Undulator Hall might go outside of the safe range and potentially could require removal and retuning of all the segments. In this note we estimate changes that can be expected in the Undulator Hall air temperature for three fault scenarios: (1) System-wide power failure; (2) Heating Ventilation and Air Conditioning (HVAC) system shutdown; and (3) HVAC system temperature regulation fault. We find that for either a system-wide power failure or an HVAC system shutdown (with the technical equipment left on), the short-term temperature changes of the air would be modest due to the ability of the walls and floor to act as a heat ballast. No action would be needed to protect the undulator system in the event of a system-wide power failure. Some action to adjust the heat balance, in the case of the HVAC power failure with the equipment left on, might be desirable but is not required. On the other hand, a temperature regulation failure of the HVAC system can quickly cause large excursions in air temperature and prompt action would be required to avoid damage to the undulator system.

  17. Modeling monthly mean air temperature for Brazil

    NASA Astrophysics Data System (ADS)

    Alvares, Clayton Alcarde; Stape, José Luiz; Sentelhas, Paulo Cesar; de Moraes Gonçalves, José Leonardo

    2013-08-01

    Air temperature is one of the main weather variables influencing agriculture around the world. Its availability, however, is a concern, mainly in Brazil where the weather stations are more concentrated on the coastal regions of the country. Therefore, the present study had as an objective to develop models for estimating monthly and annual mean air temperature for the Brazilian territory using multiple regression and geographic information system techniques. Temperature data from 2,400 stations distributed across the Brazilian territory were used, 1,800 to develop the equations and 600 for validating them, as well as their geographical coordinates and altitude as independent variables for the models. A total of 39 models were developed, relating the dependent variables maximum, mean, and minimum air temperatures (monthly and annual) to the independent variables latitude, longitude, altitude, and their combinations. All regression models were statistically significant ( α ≤ 0.01). The monthly and annual temperature models presented determination coefficients between 0.54 and 0.96. We obtained an overall spatial correlation higher than 0.9 between the models proposed and the 16 major models already published for some Brazilian regions, considering a total of 3.67 × 108 pixels evaluated. Our national temperature models are recommended to predict air temperature in all Brazilian territories.

  18. Middle Pliocene sea surface temperature variability

    USGS Publications Warehouse

    Dowsett, H.J.; Chandler, M.A.; Cronin, T. M.; Dwyer, G.S.

    2005-01-01

    Estimates of sea surface temperature (SST) based upon foraminifer, diatom, and ostracod assemblages from ocean cores reveal a warm phase of the Pliocene between about 3.3 and 3.0 Ma. Pollen records and plant megafossils, although not as well dated, show evidence for a warmer climate at about the same time. Increased greenhouse forcing and altered ocean heat transport are the leading candidates for the underlying cause of Pliocene global warmth. Despite being a period of global warmth, this interval encompasses considerable variability. Two new SST reconstructions are presented that are designed to provide a climatological error bar for warm peak phases of the Pliocene and to document the spatial distribution and magnitude of SST variability within the mid-Pliocene warm period. These data suggest long-term stability of low-latitude SST and document greater variability in regions of maximum warming. Copyright 2005 by the American Geophysical Union.

  19. Sea surface temperatures from VAS MSI data

    NASA Technical Reports Server (NTRS)

    Bates, J. J.

    1984-01-01

    A procedure is developed for estimating sea surface temperatures from multispectral image data acquired from the VISSR atmospheric sounder on the geostationary GOES satellites. Theoretical regression equations for two and three infrared window channels are empirically tuned using clear field of view satellite radiances matched with reports of SST from NOAA fixed environmental buoys. The empirical regression equations are then used to produce daily regional analyses of SST. Monthly mean SST's for the western North Atlantic and the eastern equatorial Pacific during March and July 1982 were produced for use in the SST Intercomparison Workshop Series. Workshop results showed VAS SST's have a scatter of 0.8-1.0 C and a slight warm bias with respect to the other measurements of SST. The VAS SST's show no discernible bias in the region of El Chichon volcanic aerosol cloud.

  20. Sea surface temperature variability: patterns and mechanisms.

    PubMed

    Deser, Clara; Alexander, Michael A; Xie, Shang-Ping; Phillips, Adam S

    2010-01-01

    Patterns of sea surface temperature (SST) variability on interannual and longer timescales result from a combination of atmospheric and oceanic processes. These SST anomaly patterns may be due to intrinsic modes of atmospheric circulation variability that imprint themselves upon the SST field mainly via surface energy fluxes. Examples include SST fluctuations in the Southern Ocean associated with the Southern Annular Mode, a tripolar pattern of SST anomalies in the North Atlantic associated with the North Atlantic Oscillation, and a pan-Pacific mode known as the Pacific Decadal Oscillation (with additional contributions from oceanic processes). They may also result from coupled ocean-atmosphere interactions, such as the El Niño-Southern Oscillation phenomenon in the tropical Indo-Pacific, the tropical Atlantic Niño, and the cross-equatorial meridional modes in the tropical Pacific and Atlantic. Finally, patterns of SST variability may arise from intrinsic oceanic modes, notably the Atlantic Multidecadal Oscillation. PMID:21141660

  1. Atmospheric organochlorine pollutants and air-sea exchange of hexachlorocyclohexane in the Bering and Chukchi Seas

    USGS Publications Warehouse

    Hinckley, D.A.; Bidleman, T.F.; Rice, C.P.

    1991-01-01

    Organochlorine pesticides have been found in Arctic fish, marine mammals, birds, and plankton for some time. The lack of local sources and remoteness of the region imply long-range transport and deposition of contaminants into the Arctic from sources to the south. While on the third Soviet-American Joint Ecological Expedition to the Bering and Chukchi Seas (August 1988), high-volume air samples were taken and analyzed for organochlorine pesticides. Hexachlorocyclohexane (HCH), hexachlorobenzene, polychlorinated camphenes, and chlordane (listed in order of abundance, highest to lowest) were quantified. The air-sea gas exchange of HCH was estimated at 18 stations during the cruise. Average alpha-HCH concentrations in concurrent atmosphere and surface water samples were 250 pg m-3 and 2.4 ng L-1, respectively, and average gamma-HCH concentrations were 68 pg m-3 in the atmosphere and 0.6 ng L-1 in surface water. Calculations based on experimentally derived Henry's law constants showed that the surface water was undersaturated with respect to the atmosphere at most stations (alpha-HCH, average 79% saturation; gamma-HCH, average 28% saturation). The flux for alpha-HCH ranged from -47 ng m-2 day-1 (sea to air) to 122 ng m-2 d-1 (air to sea) and averaged 25 ng m-2 d-1 air to sea. All fluxes of gamma-HCH were from air to sea, ranged from 17 to 54 ng m-2 d-1, and averaged 31 ng m-2 d-1.

  2. Atmospheric organochlorine pollutants and air-sea exchange of hexachlorocyclohexane in the Bering and Chukchi seas

    NASA Astrophysics Data System (ADS)

    Hinckley, Daniel A.; Bidleman, Terry F.; Rice, Clifford P.

    1991-04-01

    Organochlorine pesticides have been found in Arctic fish, marine mammals, birds, and plankton for some time. The lack of local sources and remoteness of the region imply long-range transport and deposition of contaminants into the Arctic from sources to the south. While on the third Soviet-American Joint Ecological Expedition to the Bering and Chukchi Seas (August 1988), high-volume air samples were taken and analyzed for Organochlorine pesticides. Hexachlorocyclohexane (HCH), hexachlorobenzene, polychlorinated camphenes, and chlordane (listed in order of abundance, highest to lowest) were quantified. The air-sea gas exchange of HCH was estimated at 18 stations during the cruise. Average α-HCH concentrations in concurrent atmosphere and surface water samples were 250 pg m-3 and 2.4 ng L-1, respectively, and average γ-HCH concentrations were 68 pg m-3 in the atmosphere and 0.6 ng L-1 in surface water. Calculations based on experimentally derived Henry's law constants showed that the surface water was undersaturated with respect to the atmosphere at most stations (α-HCH, average 79% saturation; γ-HCH, average 28% saturation). The flux for α-HCH ranged from -47 ng m-2 day-1 (sea to air) to 122 ng m-2 d-1 (air to sea) and averaged 25 ng m-2 d-1 air to sea. All fluxes of γ-HCH were from air to sea, ranged from 17 to 54 ng m-2 d-1, and averaged 31 ng m-2 d-1.

  3. Surface heat flux parameterizations and tropical Pacific sea surface temperature simulations

    SciTech Connect

    Giese, B.S. University Corp. for Atmospheric Research, Boulder, CO ); Cayan, D.R. )

    1993-04-15

    The authors report on a study of the problem of getting good model results for the sea surface temperature in the tropical Pacific ocean. The tropical Pacific is particularly important because of its size, the large areas of warm surface temperature, its impact on global atmospheric circulation, and the fact that it serves as an indicator of climatic variations. To simulate sea surface temperature it is necessary to have an energy budget which fits into a general ocean circulation model. The main input, from solar flux, is not well known in the tropical Pacific. The authors use two different models to describe the latent flux and the radiative flux at the sea surface. Parameters of concern include the relative humidity, air-sea temperature difference, latent heat formulae, and radiative heat flux. They use these parameters in their models in different ways, and compare results with measurement sets from the Tropical Pacific.

  4. Distribution and air-sea fluxes of carbon dioxide on the Chukchi Sea shelf

    NASA Astrophysics Data System (ADS)

    Pipko, I. I.; Pugach, S. P.; Repina, I. A.; Dudarev, O. V.; Charkin, A. N.; Semiletov, I. P.

    2015-12-01

    This article presents the results of long-term studies of the dynamics of carbonate parameters and air-sea carbon dioxide fluxes on the Chukchi Sea shelf during the summer. As a result of the interaction of physical and biological factors, the surface waters on the west of Chukchi Sea were undersaturated with carbon dioxide when compared with atmospheric air; the partial pressure of CO2 varied in the range from 134 to 359 μatm. The average value of CO2 flux in the Chukchi Sea per unit area varied in the range from-2.4 to-22.0 mmol /(m2 day), which is significantly higher than the average value of CO2 flux in the World Ocean. It has been estimated that the minimal mass of C absorbed by the surface of Chukchi Sea from the atmosphere during ice-free season is 13 × 1012 g; a great part of this carbon is transported to the deeper layers of sea and isolated from the atmosphere for a long period of time. The studies of the carbonate system of the Chukchi Sea, especially of its western part, will provide some new data on the fluxes of carbon dioxide in the Arctic Ocean and their changes. Our analysis can be used for an interpretation of the satellite assessment of CO2 fluxes and dissolved CO2 distribution in the upper layers of the ocean.

  5. Sea Surface Temperature from EUMETSAT Including Sentinel-3 SLSTR

    NASA Astrophysics Data System (ADS)

    O'Carroll, Anne; Bonekamp, Hans; Montagner, Francois; Santacesaria, Vincenzo; Tomazic, Igor

    2015-12-01

    The paper gives an overview of sea surface temperature (SST) activities at EUMETSAT including information on SST planned from the Sea and Land Surface Temperature Radiometer (SLSTR). Operational oceanography activities within the Marine Applications group at EUMETSAT continue with a focus on SST, sea surface winds, sea-ice products, radiative fluxes, significant wave height and sea surface topography. These are achieved through the mandatory, optional and third-party programmes, and for some products with the EUMETSAT Ocean and Sea-Ice Satellite Application Facility (OSI SAF). Progress towards products from sea-ice surface temperature, ocean colour products, turbidity and aerosol optical depth over water continue. Information on oceanography products from EUMETSAT can be found through the product navigator (http://navigator.eumetsat.int). EUMETSAT have been collaborating with ESA for a number of years on the development of SST for SLSTR.

  6. Sea-surface temperature fronts in the Yellow and East China Seas from TRMM microwave imager data

    NASA Astrophysics Data System (ADS)

    Huang, Daji; Zhang, Tao; Zhou, Feng

    2010-06-01

    Swath data from the Tropical Rainfall Measuring Mission microwave imager of sea-surface temperatures (SST) from 1998 to 2005 have been used to analyze the climatology and seasonal variability of the SST fronts in the Yellow and East China Seas (YES). Seven fronts have been identified and placed into three categories, namely, (1) the shelf-break front (Kuroshio Front), (2) the coastal fronts (Zhe-Min, Jiangsu, Shangdong Peninsula, Western Korean, and Western Chejudo Fronts), and (3) the shelf front (Western Yellow Sea Shelf Front). The Kuroshio Front exists from December through May, with the maximum SST gradient and highest frontal probability in April. The five coastal fronts exist year-round, all with their maximum SST gradient and highest frontal probability in February. The shelf front in the western Yellow Sea exists only from January to March. Frontogenesis in winter is due to effects of both air-sea heat exchange and advection by currents. The coastal fronts in the stratified months are expressed as tidal fronts. The coastal frontal zones coincide with the major spawning grounds of fish in the YES. The overwintering fishery ground in the Yellow Sea overlaps with the narrow band of favorable water temperature in the frontal zone. The overwintering grounds in the East China Sea are broad and bounded by fronts.

  7. Sea surface temperature variability in the Colombian Basin, Caribbean Sea

    NASA Astrophysics Data System (ADS)

    Ruiz-Ochoa, Mauricio; Beier, Emilio; Bernal, Gladys; Barton, Eric Desmond

    2012-06-01

    Daily sea surface temperature (SST) data from the Advanced Very High Resolution Radiometer (AVHRR) database with ∼4 km of spatial resolution were analyzed for the period 1985-2009 in the Colombian Basin using harmonic and empirical orthogonal function (EOF) analysis. The data were compared with observational records in the Rosario Island National Park at 10 m depth (T10) from March 2003 to August 2005. SST values were higher than T10 from June to October (rainy season), but similar from December to February (dry season); both data sets have similar coefficient of variation. The mean SST distribution varies spatially, with minimum SST values in the coastal zone of La Guajira Peninsula and maximum values in the Darien and Mosquitos Gulfs. The seasonal variability explains up to 75% of the total variability in La Guajira, a high value compared with 40% in the Mosquitos Gulf. The most important feature of the splitting of SST variation into annual and semiannual harmonics in La Guajira is the relationship between their amplitudes. These are of the same order, which is not common in other ocean zones, where the semiannual component is only a small fraction of the annual dominated by the solar warming. The river water discharge, highest from August to November, produces low density surface water, reduces vertical mixing and limits the absorption of solar radiation to a thin surface layer, explaining the discrepancy between SST and T10 in the rainy season. The decomposition of the SST in EOFs indicated that the dominant mode of the basin is a uniform interannual variation in phase with the North Tropical Atlantic Index. The second mode, representing the variability of the Guajira upwelling, covaried strongly with the second mode of wind stress curl. The third mode reflected the role of the vertical atmospheric circulation cell associated with the Caribbean Low Level Jet off Central America.

  8. Observational Buoy Studies of Coastal Air-Sea Fluxes.

    NASA Astrophysics Data System (ADS)

    Frederickson, Paul A.; Davidson, Kenneth L.

    2003-02-01

    Recent advancements in measurement and analysis techniques have allowed air-sea fluxes to be measured directly from moving platforms at sea relatively easily. These advances should lead to improved surface flux parameterizations, and thus to improved coupled atmosphere-ocean modeling. The Naval Postgraduate School has developed a `flux buoy' (FB) that directly measures air-sea fluxes, mean meteorological parameters, and one-dimensional and directional wave spectra. In this study, the FB instrumentation and data analysis techniques are described, and the data collected during two U.S. east coast buoy deployments are used to examine the impact of atmospheric and surface wave properties on air-sea momentum transfer in coastal ocean regions. Data obtained off Duck, North Carolina, clearly show that, for a given wind speed, neutral drag coefficients in offshore winds are higher than those in onshore winds. Offshore wind drag coefficients observed over the wind speed range from 5 to 21 m s1 were modeled equally well by a linear regression on wind speed, and a Charnock model with a constant of 0.016. Measurements from an FB deployment off Wallops Island, Virginia, show that neutral drag coefficients in onshore winds increase as the wind-wave direction differences increase, especially beyond ±60°.

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

    NASA Technical Reports Server (NTRS)

    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.

  10. Effects of rising temperature on the viability of an important sea turtle rookery

    NASA Astrophysics Data System (ADS)

    Laloë, Jacques-Olivier; Cozens, Jacquie; Renom, Berta; Taxonera, Albert; Hays, Graeme C.

    2014-06-01

    A warming world poses challenges for species with temperature-dependent sex determination, including sea turtles, for which warmer incubation temperatures produce female hatchlings. We combined in situ sand temperature measurements with air temperature records since 1850 and predicted warming scenarios from the Intergovernmental Panel on Climate Change to derive 250-year time series of incubation temperatures, hatchling sex ratios, and operational sex ratios for one of the largest sea turtles rookeries globally (Cape Verde Islands, Atlantic). We estimate that light-coloured beaches currently produce 70.10% females whereas dark-coloured beaches produce 93.46% females. Despite increasingly female skewed sex ratios, entire feminization of this population is not imminent. Rising temperatures increase the number of breeding females and hence the natural rate of population growth. Predicting climate warming impacts across hatchlings, male-female breeding ratios and nesting numbers provides a holistic approach to assessing the conservation concerns for sea turtles in a warming world.

  11. Spatial interpolation of monthly mean air temperature data for Latvia

    NASA Astrophysics Data System (ADS)

    Aniskevich, Svetlana

    2016-04-01

    Temperature data with high spatial resolution are essential for appropriate and qualitative local characteristics analysis. Nowadays the surface observation station network in Latvia consists of 22 stations recording daily air temperature, thus in order to analyze very specific and local features in the spatial distribution of temperature values in the whole Latvia, a high quality spatial interpolation method is required. Until now inverse distance weighted interpolation was used for the interpolation of air temperature data at the meteorological and climatological service of the Latvian Environment, Geology and Meteorology Centre, and no additional topographical information was taken into account. This method made it almost impossible to reasonably assess the actual temperature gradient and distribution between the observation points. During this project a new interpolation method was applied and tested, considering auxiliary explanatory parameters. In order to spatially interpolate monthly mean temperature values, kriging with external drift was used over a grid of 1 km resolution, which contains parameters such as 5 km mean elevation, continentality, distance from the Gulf of Riga and the Baltic Sea, biggest lakes and rivers, population density. As the most appropriate of these parameters, based on a complex situation analysis, mean elevation and continentality was chosen. In order to validate interpolation results, several statistical indicators of the differences between predicted values and the values actually observed were used. Overall, the introduced model visually and statistically outperforms the previous interpolation method and provides a meteorologically reasonable result, taking into account factors that influence the spatial distribution of the monthly mean temperature.

  12. Linking air-sea energy exchanges and European anchovy potential spawning ground

    NASA Astrophysics Data System (ADS)

    Grammauta, R.; Molteni, D.; Basilone, G.; Guisande, C.; Bonanno, A.; Aronica, S.; Giacalone, G.; Fontana, I.; Zora, M.; Patti, B.; Cuttitta, A.; Buscaino, G.; Sorgente, R.; Mazzola, S.

    2008-10-01

    The physical and chemical processes of the sea greatly affect the reproductive biology of fishes, mainly influencing both the numbers of spawned eggs and the survivorship of early stages up to the recruitment period. In the central Mediterranean, the European anchovy constitutes one of the most important fishery resource. Because of its short living nature and of its recruitment variability, associated to high environmental variability, this small pelagic species undergo high interannual fluctuation in the biomass levels. Despite several efforts were addressed to characterize fishes spawning habitat from the oceanographic point of view, very few studies analyze the air-sea exchanges effects. To characterize the spawning habitat of these resources a specific technique (quotient rule analysis) was applied on air-sea heat fluxes, wind stress, sea surface temperature and turbulence data, collected in three oceanographic surveys during the summer period of 2004, 2005 and 2006. The results showed the existence of preferred values in the examined physical variables, associated to anchovy spawning areas. Namely, for heat fluxes the values were around -40 W/m2, for wind stress 0.04-0.11 N/m2, for SST 23°C, and 300 - 500 m3s-3 for wind mixing. Despite the obtained results are preliminary, this is the first relevant analysis on the air-sea exchanges and their relationship with the fish biology of pelagic species.

  13. Intense air-sea exchange and heavy rainfall: impact of the northern Adriatic SST

    NASA Astrophysics Data System (ADS)

    Stocchi, P.; Davolio, S.

    2016-02-01

    Over the northern Adriatic basin, intense air-sea interactions are often associated with heavy precipitation over the mountainous areas surrounding the basin. In this study, a high-resolution mesoscale model is employed to simulate three severe weather events and to evaluate the effect of the sea surface temperature on the intensity and location of heavy rainfall. The sensitivity tests show that the impact of SST varies among the events and it mainly involves the modification of the PBL characteristics and thus the flow dynamics and its interaction with the orography.

  14. Biopolymers form a gelatinous microlayer at the air-sea interface when Arctic sea ice melts

    PubMed Central

    Galgani, Luisa; Piontek, Judith; Engel, Anja

    2016-01-01

    The interface layer between ocean and atmosphere is only a couple of micrometers thick but plays a critical role in climate relevant processes, including the air-sea exchange of gas and heat and the emission of primary organic aerosols (POA). Recent findings suggest that low-level cloud formation above the Arctic Ocean may be linked to organic polymers produced by marine microorganisms. Sea ice harbors high amounts of polymeric substances that are produced by cells growing within the sea-ice brine. Here, we report from a research cruise to the central Arctic Ocean in 2012. Our study shows that microbial polymers accumulate at the air-sea interface when the sea ice melts. Proteinaceous compounds represented the major fraction of polymers supporting the formation of a gelatinous interface microlayer and providing a hitherto unrecognized potential source of marine POA. Our study indicates a novel link between sea ice-ocean and atmosphere that may be sensitive to climate change. PMID:27435531

  15. Biopolymers form a gelatinous microlayer at the air-sea interface when Arctic sea ice melts.

    PubMed

    Galgani, Luisa; Piontek, Judith; Engel, Anja

    2016-01-01

    The interface layer between ocean and atmosphere is only a couple of micrometers thick but plays a critical role in climate relevant processes, including the air-sea exchange of gas and heat and the emission of primary organic aerosols (POA). Recent findings suggest that low-level cloud formation above the Arctic Ocean may be linked to organic polymers produced by marine microorganisms. Sea ice harbors high amounts of polymeric substances that are produced by cells growing within the sea-ice brine. Here, we report from a research cruise to the central Arctic Ocean in 2012. Our study shows that microbial polymers accumulate at the air-sea interface when the sea ice melts. Proteinaceous compounds represented the major fraction of polymers supporting the formation of a gelatinous interface microlayer and providing a hitherto unrecognized potential source of marine POA. Our study indicates a novel link between sea ice-ocean and atmosphere that may be sensitive to climate change. PMID:27435531

  16. 40 CFR 91.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must...

  17. 40 CFR 91.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must...

  18. 40 CFR 91.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must...

  19. 40 CFR 91.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must...

  20. 40 CFR 91.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must...

  1. Temporal variability of remotely sensed suspended sediment and sea surface temperature patterns in Mobile Bay, Alabama

    USGS Publications Warehouse

    Rucker, J.B.; Stumpf, R.P.; Schroeder, W.W.

    1990-01-01

    Distribution patterns of suspended sediments and sea surface temperatures in, Mobile Bay were derived from algorithms using digital data from the visible, near infrared, and infrared channels of the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-TIROS-N satellite. Closely spaced AVHRR scenes for January 20, 24, and 29, 1982, were compared with available environmental information taken during the same period. A complex interaction between river discharge, winds, and astronomical tides controlled the distribution patterns of suspended sediments. These same variables, coupled with air temperatures, also governed the distribution patterns of sea surface temperatures. ?? 1990 Estuarine Research Federation.

  2. Balloons and Bottles: Activities on Air-Sea Heat Exchange.

    ERIC Educational Resources Information Center

    Murphree, Tom

    1998-01-01

    Presents an activity designed to demonstrate how heating and cooling an air mass affects its temperature, volume, density, and pressure. Illustrates how thermal energy can cause atmospheric motion such as expansion, contraction, and winds. (Author/WRM)

  3. The role of sea ice in the temperature-precipitation feedback of glacial cycles

    NASA Astrophysics Data System (ADS)

    Gildor, Hezi; Ashkenazy, Yosef; Tziperman, Eli; Lev, Ilit

    2014-08-01

    The response of the hydrological cycle to climate variability and change is a critical open question, where model reliability is still unsatisfactory, yet upon which past climate history can shed some light. Sea ice is a key player in the climate system and in the hydrological cycle, due to its strong albedo effect and its insulating effect on local evaporation and air-sea heat flux. Using an atmospheric general circulation model with specified sea surface temperature and sea-ice distribution, the role of sea ice in the hydrological cycle is investigated under last glacial maximum (LGM) and present day conditions, and by studying its contribution to the "temperature-precipitation feedback". By conducting a set of sensitivity experiments in which the albedo and thickness of the sea ice are varied, the various effects of sea ice in the hydrological cycle are isolated. It is demonstrated that for a cold LGM like state, a warmer climate (as a result of reduced sea-ice cover) leads to an increase in snow precipitation over the ice sheets. The insulating effect of the sea ice on the hydrological cycle is found to be larger than the albedo effect. These two effects interact in a nonlinear way and their total effect is not equal to summing their separate contribution.

  4. A statistical analysis of sea temperature data. A statistical analysis of sea temperature data

    NASA Astrophysics Data System (ADS)

    Lorentzen, Torbjørn

    2015-02-01

    The paper analyzes sea temperature series measured at two geographical locations along the coast of Norway. We address the question whether the series are stable over the sample period 1936-2012 and whether we can measure any signal of climate change in the regional data. We use nonstandard supF, OLS-based CUSUM, RE, and Chow tests in combination with the Bai-Perron's structural break test to identify potential changes in the temperature. The augmented Dickey-Fuller, the KPSS, and the nonparametric Phillips-Perron tests are in addition applied in the evaluation of the stochastic properties of the series. The analysis indicates that both series undergo similar structural instabilities in the form of small shifts in the temperature level. The temperature at Lista (58° 06' N, 06° 38' E) shifts downward about 1962 while the Skrova series (68° 12' N, 14° 10' E) shifts to a lower level about 1977. Both series shift upward about 1987, and after a period of increasing temperature, both series start leveling off about the turn of the millennium. The series have no significant stochastic or deterministic trend. The analysis indicates that the mean temperature has moved upward in decadal, small steps since the 1980s. The result is in accordance with recent analyses of sea temperatures in the North Atlantic. The findings are also related to the so-called hiatus phenomenon where natural variation in climate can mask global warming processes. The paper contributes to the discussion of applying objective methods in measuring climate change.

  5. Climatic Impacts of a Stochastic Parameterization of Air-Sea Fluxes

    NASA Astrophysics Data System (ADS)

    Williams, P. D.

    2014-12-01

    The atmosphere and ocean are coupled by the exchange of fluxes across the ocean surface. Air-sea fluxes vary partly on scales that are too small and fast to be resolved explicitly in numerical models of weather and climate, making them a candidate for stochastic parameterization. This presentation proposes a nonlinear physical mechanism by which stochastic fluctuations in the air-sea buoyancy flux may modify the mean climate, even though the mean fluctuation is zero. The mechanism relies on a fundamental asymmetry in the physics of the ocean mixed layer: positive surface buoyancy fluctuations cannot undo the vertical mixing caused by negative fluctuations. The mechanism has much in common with Stommel's mixed-layer demon. The presentation demonstrates the mechanism in climate simulations with a comprehensive coupled atmosphere-ocean general circulation model (SINTEX-G). In the SINTEX-G simulations with stochastic air-sea buoyancy fluxes, significant changes are detected in the time-mean oceanic mixed-layer depth, sea-surface temperature, atmospheric Hadley circulation, and net upward water flux at the sea surface. Also, El Niño Southern Oscillation (ENSO) variability is significantly increased. The findings demonstrate that noise-induced drift and noise-enhanced variability, which are familiar concepts from simple climate models, continue to apply in comprehensive climate models with millions of degrees of freedom. The findings also suggest that the lack of representation of sub-grid variability in air-sea fluxes may contribute to some of the biases exhibited by contemporary climate models.

  6. Gulf of Mexico Air/Sea Interaction: Measurements and Initial Data Characterization

    NASA Astrophysics Data System (ADS)

    MacDonald, C.; Huang, C. H.; Roberts, P. T.; Bariteau, L.; Fairall, C. W.; Gibson, W.; Ray, A.

    2011-12-01

    Corporate, government, and university researchers collaborated to develop an atmospheric boundary layer environmental observations program on an offshore platform in the Gulf of Mexico. The primary goals of this project were to provide data to (1) improve our understanding of boundary layer processes and air-sea interaction over the Gulf of Mexico; (2) improve regional-scale meteorological and air quality modeling; and (3) provide a framework for advanced offshore measurements to support future needs such as emergency response, exploration and lease decisions, wind energy research and development, and meteorological and air quality forecasting. In October 2010, meteorological and oceanographic sensors were deployed for an extended period (approximately 12 months) on a Chevron service platform (ST 52B, 90.5W, 29N) to collect boundary layer and sea surface data sufficient to support these objectives. This project has significant importance given the large industrial presence in the Gulf, sizeable regional population nearby, and the recognized need for precise and timely pollutant forecasts. Observations from this project include surface meteorology; sodar marine boundary layer winds; microwave radiometer profiles of temperature, relative humidity, and liquid water; ceilometer cloud base heights; water temperature and current profiles; sea surface temperature; wave height statistics; downwelling solar and infrared radiation; and air-sea turbulent momentum and heat fluxes. This project resulted in the collection of an unprecedented set of boundary layer measurements over the Gulf of Mexico that capture the range of meteorological and oceanographic interactions and processes that occur over an entire year. This presentation will provide insight into the logistical and scientific issues associated with the deployment and operations of unique measurements in offshore areas and provide results from an initial data analysis of boundary layer processes over the Gulf of

  7. The Impact of Sea Surface Temperature Front on Stratus-Sea Fog over the Yellow and East China Seas

    NASA Astrophysics Data System (ADS)

    Zhang, S.; Li, M.; Liu, F.

    2013-12-01

    A stratus-sea fog event occurred on 3 June 2011 over the Yellow and East China Seas (as shown in figure) is investigated observationally and numerically. Emphasis is put on the influences of the sea surface temperature front (SSTF) and of the synoptic circulations on the transition of stratus to sea fog. The southerly winds from a synoptic high pressure transport water vapor from the East China Sea to the Yellow Sea, while the subsidence induced by the high contributes to the formation of the temperature inversion on the top of the stratus or stratocumulus that appears mainly over the warm flank of a sea surface temperature front in the East China Sea. Forced by the SSTF, there is a secondary cell within the atmospheric boundary layer (ABL), with a sinking branch on the cold flank and a rising one on the warm flank of the SSTF. This sinking branch, in phase with the synoptic subsidence, forces the stratus or stratocumulus to lower in the elevation getting close to the sea surface as these clouds move northward driven by the southerly winds. The cloud droplets can either reach to the sea surface directly or evaporate into water vapor that may condense again when coming close to the cold sea surface to form fog. In this later case, the stratus and fog may separate. The cooling effect of cold sea surface counteracts the adiabatic heating induced by the subsidence and thus helps the transition of stratus to sea fog in the southern Yellow Sea. By smoothing the SSTF in the numerical experiment, the secondary cell weakens and the sea fog patches shrink obviously over the cold flank of the SSTF though the synoptic subsidence and moist advection still exist. A conceptual model is suggested for the transition of stratus to sea fog in the Yellow and East China Seas, which is helpful for the forecast of sea fog over these areas. The satellite visible image of the stratus-fog event. The fog appears in the Yellow Sea and the stratocumulus in the East China Sea.

  8. Simultaneous measurements of skin sea surface temperature and sea surface emissivity from a single thermal imagery.

    PubMed

    Yoshimori, Kyu; Tamba, Sumio; Yokoyama, Ryuzo

    2002-08-20

    A novel method, to our knowledge, to measure simultaneously the thermal emissivity and skin temperature of a sea surface has been developed. The proposed method uses an infrared image that includes a sea surface and a reference object located near the surface. By combining this image with sky radiation temperature, we retrieve both skin sea surface temperature and sea surface emissivity from the single infrared image. Because the method requires no knowledge of thermal radiative properties of actual sea surfaces, it can be used even for a contaminated sea surface whose emissivity is hard to determine theoretically, e.g., oil slicks or slicks produced by biological wastes. Experimental results demonstrate that the estimated emissivity agrees with the theoretical prediction and, also, the recovered temperature distribution of skin sea surface has no appreciable high-temperature area that is due to reflection of the reference object. The method allows the acquisition of match-up data of radiometric sea surface temperatures that precisely correspond to the satellite observable data. PMID:12206200

  9. Air-Sea Exchange Of CO2: A Multi-Technology Approach

    NASA Astrophysics Data System (ADS)

    Tengberg, A.; Almroth, E.; Anderson, L.; Hall, P.; Hjalmarsson, S.; Lefevre, D.; Omstedt, A.; Rutgersson, A.; Sahlee, E.; Smedman, A.; Wesslander, K.

    2006-12-01

    We report on experiences and results from a multidisciplinary project in which we try to elucidate the complex processes involved in air-sea exchange of CO2. This study was performed in the Baltic Sea (off the Swedish island Gotland) and combined the following technologies: - Meteorological measurements of wind, turbulence, temperature, humidity, humidity flux, CO2 and CO2 flux at several levels from a fixed observation tower - Hourly PCO2 measurements with a moored automatic instrument - Collection of dissolved oxygen, temperature, salinity and turbidity data at different levels in the water column at 1-minute intervals - Daily light (PAR) and primary production measurements obtained with a moored automatic incubator - Daily primary production measurements using manual methods - Use of an acoustic current profiler to collect water column information on currents, turbulence, water level and waves - Repetitive water column profiles, from a ship, of dissolved inorganic carbon, oxygen, nutrients, alkalinity, pH, PAR, Chlorophyll A, salinity and temperature

  10. Air-sea interaction measurements in the west Mediterranean Sea during the Tyrrhenian Eddy Multi-Platform Observations Experiment

    SciTech Connect

    Schiano, M.E.; Santoleri, R.; Bignami, F.; Leonardi, R.M. ); Marullo, S. ); Boehm, E. )

    1993-02-15

    Measurements of radiative fluxes were carried out in the Tyrrhenian Sea in fall and winter as part of the Tyrrhenian Eddy Multi-Platform Observations Experiment (TEMPO). These measurements have supplied the first experimental radiation data set over this basin. Seasonal variation of the different components of the budget are investigated. Since data collection was carried out in an area in which a quasi-permanent eddy is present, the behavior of the radiation parameters across the frontal zone is analyzed. The most interesting result of the air-sea interaction in proximity of a marine front consists in the covariation of sea surface temperature and downwelling long-wave radiation. Contemporaneous satellite data show a clear correlation between sea surface structure and horizontal distribution of columnar atmospheric water content. Therefore this inhomogeneity clearly is one of the main factors responsible for the variation of the downwelling radiation across the front. A comparison between experimental data and results of some of the most widely used bulk formulae is carried out for both short- and long-wave radiation. The mean differnece between measured and empirical solar radiation values is less than 3%, while in the case of the net long-wave radiation budge, poor agreement is found. Indeed, a 30 W/m[sup 2] bias results from the comparison. This discrepancy is consistent with the imbalance between previous bulk calculations of total heat budget at the surface and corresponding hydrographical observations of heat exchange at Gibraltar. 30 refs., 6 figs., 9 tabs.

  11. An overview of sea state conditions and air-sea fluxes during RaDyO

    NASA Astrophysics Data System (ADS)

    Zappa, Christopher J.; Banner, Michael L.; Schultz, Howard; Gemmrich, Johannes R.; Morison, Russel P.; Lebel, Deborah A.; Dickey, Tommy

    2012-07-01

    Refining radiative-transfer modeling capabilities for light transmission through the sea surface requires a more detailed prescription of the sea surface roughness beyond the probability density function of the sea surface slope field. To meet this need, exciting new measurement methodologies now provide the opportunity to enhance present knowledge of sea surface roughness, especially at the microscale. In this context, two intensive field experiments using R/PFloating Instrument Platformwere staged within the Office of Naval Research's Radiance in a Dynamic Ocean (RaDyO) field program in the Santa Barbara Channel and in the central Pacific Ocean south of Hawaii. As part of this program, our team gathered and analyzed a comprehensive suite of sea surface roughness measurements designed to provide optimal coverage of fundamental optical distortion processes associated with the air-sea interface. This contribution describes the ensemble of instrumentation deployed. It provides a detailed documentation of the ambient environmental conditions that prevailed during the RaDyO field experiments. It also highlights exciting new sea surface roughness measurement capabilities that underpin a number of the scientific advances resulting from the RaDyO program. For instance, a new polarimetric imaging camera highlights the complex interplay of wind and surface currents in shaping the roughness of the sea surface that suggests the traditional Cox-Munk framework is not sufficient. In addition, the breaking crest length spectral density derived from visible and infrared imagery is shown to be modulated by the development of the wavefield (wave age) and alignment of wind and surface currents at the intermediate (dominant) scale of wave breaking.

  12. The role of bubbles during air-sea gas exchange

    NASA Astrophysics Data System (ADS)

    Emerson, Steven; Bushinsky, Seth

    2016-06-01

    The potential for using the air-sea exchange rate of oxygen as a tracer for net community biological production in the ocean is greatly enhanced by recent accuracy improvements for in situ measurements of oxygen on unmanned platforms. A limiting factor for determining the exchange process is evaluating the air-sea flux contributed by bubble processes produced by breaking waves, particularly during winter months under high winds. Highly accurate measurements of noble gases (Ne, Ar & Kr) and nitrogen, N2, in seawater are tracers of the importance of bubble process in the surface mixed layer. We use measured distributions of these gases in the ventilated thermocline of the North Pacific and an annual time series of N2 in the surface ocean of the NE Subarctic Pacific to evaluate four different air-water exchange models chosen to represent the range of model interpretation of bubble processes. We find that models must have an explicit bubble mechanism to reproduce concentrations of insoluble atmospheric gases, but there are periods when they all depart from observations. The recent model of Liang et al. (2013) stems from a highly resolved model of bubble plumes and categorizes bubble mechanisms into those that are small enough to collapse and larger ones that exchange gases before they resurface, both of which are necessary to explain the data.

  13. Trends in Surface Temperature from AIRS.

    NASA Astrophysics Data System (ADS)

    Ruzmaikin, A.; Aumann, H. H.

    2014-12-01

    To address possible causes of the current hiatus in the Earth's global temperature we investigate the trends and variability in the surface temperature using retrievals obtained from the measurements by the Atmospheric Infrared Sounder (AIRS) and its companion instrument, the Advanced Microwave Sounding Unit (AMSU), onboard of Aqua spacecraft in 2002-2014. The data used are L3 monthly means on a 1x1degree spatial grid. We separate the land and ocean temperatures, as well as temperatures in Artic, Antarctic and desert regions. We find a monotonic positive trend for the land temperature but not for the ocean temperature. The difference in the regional trends can help to explain why the global surface temperature remains almost unchanged but the frequency of occurrence of the extreme events increases under rising anthropogenic forcing. The results are compared with the model studies. This work was supported by the Jet Propulsion Laboratory of the California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  14. Updating Sea Spray Aerosol Emissions in the Community Multiscale Air Quality Model

    NASA Astrophysics Data System (ADS)

    Gantt, B.; Bash, J. O.; Kelly, J.

    2014-12-01

    Sea spray aerosols (SSA) impact the particle mass concentration and gas-particle partitioning in coastal environments, with implications for human and ecosystem health. In this study, the Community Multiscale Air Quality (CMAQ) model is updated to enhance fine mode SSA emissions, include sea surface temperature (SST) dependency, and revise surf zone emissions. Based on evaluation with several regional and national observational datasets in the continental U.S., the updated emissions generally improve surface concentrations predictions of primary aerosols composed of sea-salt and secondary aerosols affected by sea-salt chemistry in coastal and near-coastal sites. Specifically, the updated emissions lead to better predictions of the magnitude and coastal-to-inland gradient of sodium, chloride, and nitrate concentrations at Bay Regional Atmospheric Chemistry Experiment (BRACE) sites near Tampa, FL. Including SST-dependency to the SSA emission parameterization leads to increased sodium concentrations in the southeast U.S. and decreased concentrations along the Pacific coast and northeastern U.S., bringing predictions into closer agreement with observations at most Interagency Monitoring of Protected Visual Environments (IMPROVE) and Chemical Speciation Network (CSN) sites. Model comparison with California Research at the Nexus of Air Quality and Climate Change (CalNex) observations will also be discussed, with particular focus on the South Coast Air Basin where clean marine air mixes with anthropogenic pollution in a complex environment. These SSA emission updates enable more realistic simulation of chemical processes in coastal environments, both in clean marine air masses and mixtures of clean marine and polluted conditions.

  15. Predictability of winter temperature in China from previous autumn Arctic sea ice

    NASA Astrophysics Data System (ADS)

    Zuo, Jinqing; Ren, Hong-Li; Wu, Bingyi; Li, Weijing

    2016-01-01

    The potential predictability of winter temperature in China from autumn Arctic sea ice anomalies is studied by examining and statistically modeling the large-scale interannual covariability between them on the basis of singular value decomposition analysis. It is demonstrated that an intimate relationship exists between September and October sea ice anomalies in the Eurasian Arctic and following winter temperature anomalies in China, except in the Tibetan Plateau. When the autumn sea ice anomalies decline in the Eurasian Arctic, above-normal pressure anomalies appear to prevail over the region from the Eurasian Arctic to Eastern Europe and Mongolia, and below-normal anomalies prevail over the mid-latitudes of Asia and Northwestern Pacific in the following winter. Consequently, the winter Siberian High and East Asian trough are both strengthened, favoring the southward invasion of high-latitude cold air masses and thus cold temperature anomalies in China. It is found that the Siberian High plays a crucial role in delivering effects of the autumn Arctic sea ice anomalies on winter temperature variability in China. Based on this evidence, a statistical model is established to examine the potential predictability of winter temperature anomalies in China by taking the autumn Arctic sea ice signals as a predictor. Validation shows considerable skill in predicting winter temperature anomalies over a large part of China, indicating a significant potential for improving winter climate prediction in China.

  16. A microwave technique for mapping ice temperature in the Arctic seasonal sea ice zone

    SciTech Connect

    St. Germain, K.M.; Cavalieri, D.J.

    1997-07-01

    A technique for deriving ice temperature in the Arctic seasonal sea ice zone from passive microwave radiances has been developed. The algorithm operates on brightness temperatures derived from the Special Sensor Microwave/Imager (SSM/I) and uses ice concentration and type from a previously developed thin ice algorithm to estimate the surface emissivity. Comparisons of the microwave derived temperatures with estimates derived from infrared imagery of the Bering Strait yield a correlation coefficient of 0.93 and an RMS difference of 2.1 K when coastal and cloud contaminated pixels are removed. SSM/I temperatures were also compared with a time series of air temperature observations from Gambell on St. Lawrence Island and from Point Barrow, AK weather stations. These comparisons indicate that the relationship between the air temperature and the ice temperature depends on ice type.

  17. The PRISM palaeoclimate reconstruction and Pliocene sea-surface temperature

    USGS Publications Warehouse

    Dowsett, H.J.

    2007-01-01

    In this paper, I present a summary of the Pliocene Research, Interpretation and Synoptic Mapping (PRISM) palaeoenvironmental reconstruction, with emphasis on its historical development and range of boundary condition datasets. Sea-surface temperature (SST), sea level, sea ice, land cover (vegetation and ice) and topography are discussed as well as many of the assumptions required to create an integrated global-scale reconstruction. New multiproxy research shows good general agreement on the magnitude of mid-Pliocene SST warming. Future directions, including maximum and minimum SST analyses and deep ocean temperature estimates aimed at a full three-dimensional reconstruction, are presented. ?? The Micropalaeontological Society 2007.

  18. Air-sea exchange over Black Sea estimated from high resolution regional climate simulations

    NASA Astrophysics Data System (ADS)

    Velea, Liliana; Bojariu, Roxana; Cica, Roxana

    2013-04-01

    Black Sea is an important influencing factor for the climate of bordering countries, showing cyclogenetic activity (Trigo et al, 1999) and influencing Mediterranean cyclones passing over. As for other seas, standard observations of the atmosphere are limited in time and space and available observation-based estimations of air-sea exchange terms present quite large ranges of uncertainty. The reanalysis datasets (e.g. ERA produced by ECMWF) provide promising validation estimates of climatic characteristics against the ones in available climatic data (Schrum et al, 2001), while cannot reproduce some local features due to relatively coarse horizontal resolution. Detailed and realistic information on smaller-scale processes are foreseen to be provided by regional climate models, due to continuous improvements of physical parameterizations and numerical solutions and thus affording simulations at high spatial resolution. The aim of the study is to assess the potential of three regional climate models in reproducing known climatological characteristics of air-sea exchange over Black Sea, as well as to explore the added value of the model compared to the input (reanalysis) data. We employ results of long-term (1961-2000) simulations performed within ENSEMBLE project (http://ensemblesrt3.dmi.dk/) using models ETHZ-CLM, CNRM-ALADIN, METO-HadCM, for which the integration domain covers the whole area of interest. The analysis is performed for the entire basin for several variables entering the heat and water budget terms and available as direct output from the models, at seasonal and annual scale. A comparison with independent data (ERA-INTERIM) and findings from other studies (e.g. Schrum et al, 2001) is also presented. References: Schrum, C., Staneva, J., Stanev, E. and Ozsoy, E., 2001: Air-sea exchange in the Black Sea estimated from atmospheric analysis for the period 1979-1993, J. Marine Systems, 31, 3-19 Trigo, I. F., T. D. Davies, and G. R. Bigg (1999): Objective

  19. Is Air Temperature Enough to Predict Lake Surface Temperature?

    NASA Astrophysics Data System (ADS)

    Piccolroaz, S.; Toffolon, M.; Majone, B.

    2014-12-01

    Lake surface water (LST) is a key factor that controls most of the physical and ecological processes occurring in lakes. Reliable estimates are especially important in the light of recent studies, which revealed that inland water bodies are highly sensitive to climate, and are rapidly warming throughout the world. However, an accurate estimation of LST usually requires a significant amount of information that is not always available. In this work, we present an application of air2water, a lumped model that simulates LST as a function of air temperature only. In addition, air2water allows for a qualitative evaluation of the depth of the epilimnion during the annual stratification cycle. The model consists in a simplification of the complete heat budget of the well-mixed surface layer, and has a few parameters (from 4 to 8 depending on the version) that summarize the role of the different heat flux components. Model calibration requires only air and water temperature data, possibly covering sufficiently long historical periods in order to capture inter-annual variability and long-term trends. During the calibration procedure, the information included in input data is retrieved to directly inform model parameters, which can be used to classify the thermal behavior of the lake. In order to investigate how thermal dynamics are related to morphological features, the model has been applied to 14 temperate lakes characterized by different morphological and hydrological conditions, by different sources of temperature data (buoys, satellite), and by variable frequency of acquisition. A good agreement between observed and simulated LST has been achieved, with a RMSE in the order of 1°C, which is fully comparable to the performances of more complex process-based models. This application allowed for a deeper understanding of the thermal response of lakes as a function of their morphology, as well as for specific analyses as for example the investigation of the exceptional

  20. Identifying Modes of Temperature Variability Using AIRS Data.

    NASA Astrophysics Data System (ADS)

    Ruzmaikin, A.; Aumann, H. H.; Yung, Y.

    2007-12-01

    We use the Atmospheric Infrared Sounder (AIRS) and Advance Microwave Sounding Unit (AMSU) data obtained on Aqua spacecraft to study mid-tropospheric temperature variability between 2002-2007. The analysis is focused on daily zonal means of the AIRS channel at 2388 1/cm in the CO2 R-branch and the AMSU channel #5 in the 57 GHz Oxygen band, both with weighting function peaking in the mid-troposphere (400 mb) and the matching sea surface temperature from NCEP (Aumann et al., 2007). Taking into account the nonlinear and non- stationary behavior of the temperature we apply the Empirical Mode Decomposition (Huang et al., 1998) to better separate modes of variability. All-sky (cloudy) and clear sky, day and night data are analyzed. In addition to the dominant annual variation, which is nonlinear and latitude dependent, we identified the modes with higher frequency and inter-annual modes. Some trends are visible and we apply stringent criteria to test their statistical significance. References: Aumann, H. H., D. T. Gregorich, S. E. Broberg, and D. A. Elliott, Geophys. Res. Lett., 34, L15813, doi:10.1029/2006GL029191, 2007. Huang, N. E. Z. Shen, S. R. Long, M. C. Wu, H. H. Shih, Q. Zheng, N.-C. Yen, C. C. Tung, and H. H. Liu, Proc. R. Soc. Lond., A 454, 903-995, 1998.

  1. Uncertainties of satellite-derived surface skin temperatures in the polar oceans: MODIS, AIRS/AMSU, and AIRS only

    NASA Astrophysics Data System (ADS)

    Kang, H.-J.; Yoo, J.-M.; Jeong, M.-J.; Won, Y.-I.

    2015-10-01

    Uncertainties in the satellite-derived surface skin temperature (SST) data in the polar oceans during two periods (16-24 April and 15-23 September) 2003-2014 were investigated and the three data sets were intercompared as follows: MODerate Resolution Imaging Spectroradiometer Ice Surface Temperature (MODIS IST), the SST of the Atmospheric Infrared Sounder/Advanced Microwave Sounding Unit-A (AIRS/AMSU), and AIRS only. The AIRS only algorithm was developed in preparation for the degradation of the AMSU-A. MODIS IST was systematically warmer up to 1.65 K at the sea ice boundary and colder down to -2.04 K in the polar sea ice regions of both the Arctic and Antarctic than that of the AIRS/AMSU. This difference in the results could have been caused by the surface classification method. The spatial correlation coefficient of the AIRS only to the AIRS/AMSU (0.992-0.999) method was greater than that of the MODIS IST to the AIRS/AMSU (0.968-0.994). The SST of the AIRS only compared to that of the AIRS/AMSU had a bias of 0.168 K with a RMSE of 0.590 K over the Northern Hemisphere high latitudes and a bias of -0.109 K with a RMSE of 0.852 K over the Southern Hemisphere high latitudes. There was a systematic disagreement between the AIRS retrievals at the boundary of the sea ice, because the AIRS only algorithm utilized a less accurate GCM forecast over the seasonally varying frozen oceans than the microwave data. The three data sets (MODIS, AIRS/AMSU and AIRS only) showed significant warming rates (2.3 ± 1.7 ~ 2.8 ± 1.9 K decade-1) in the northern high regions (70-80° N) as expected from the ice-albedo feedback. The systematic temperature disagreement associated with surface type classification had an impact on the resulting temperature trends.

  2. Uncertainties of satellite-derived surface skin temperatures in the polar oceans: MODIS, AIRS/AMSU, and AIRS only

    NASA Astrophysics Data System (ADS)

    Kang, H.-J.; Yoo, J.-M.; Jeong, M.-J.; Won, Y.-I.

    2015-05-01

    Uncertainties in the satellite-derived Surface Skin Temperature (SST) data in the polar oceans during two periods (16-24 April and 15-23 September) of 2003-2014 were investigated and the three datasets were intercompared as follows: MODerate Resolution Imaging Spectroradiometer Ice Surface Temperature (MODIS IST), the SST of the Atmospheric Infrared Sounder/Advanced Microwave Sounding Unit-A (AIRS/AMSU), and AIRS only. AIRS only algorithm was developed in preparation for the degradation of the AMSU-A. MODIS IST was systematically up to 1.65 K warmer at the sea ice boundary and up to 2.04 K colder in the polar sea ice regions of both the Arctic and Antarctic than that of the AIRS/AMSU. This difference in the results could have been caused by the surface classification method. The spatial correlation coefficient of the AIRS only to the AIRS/AMSU (0.992-0.999) method was greater than that of the MODIS IST to the AIRS/AMSU (0.968-0.994). The SST of the AIRS only compared to that of the AIRS/AMSU had a bias of 0.168 K with a RMSE of 0.590 K over the Northern Hemisphere high latitudes and a bias of -0.109 K with a RMSE of 0.852 K over the Southern Hemisphere high latitudes. There was a systematic disagreement between the AIRS retrievals at the boundary of the sea ice, because the AIRS only algorithm utilized a~less accurate GCM forecast over the seasonally-varying frozen oceans than the microwave data. The three datasets (MODIS, AIRS/AMSU and AIRS only) showed significant warming rates (2.3 ± 1.7 ~2.8 ± 1.9 K decade-1) in the northern high latitude regions (70-80° N) as expected from the ice-albedo feedback. The systematic temperature disagreement associated with surface type classification had an impact on the resulting temperature trends.

  3. Unravelling air-sea interactions driven by photochemistry in the sea-surface microlayer

    NASA Astrophysics Data System (ADS)

    George, Christian; Alpert, Peter; Tinel, Liselotte; Rossignol, Stéphanie; Perrier, Sébastien; Bernard, Francois; Ciuraru, Raluca; Hayeck, Nathalie

    2016-04-01

    Interfaces are ubiquitous in the environment, and in addition many atmospheric key processes, such as gas deposition, aerosol and cloud formation are, at one stage or the other, strongly impacted by physical- and chemical processes occurring at interfaces. Unfortunately, these processes have only been suggested and discussed but never fully addressed because they were beyond reach. We suggest now that photochemistry or photosensitized reactions exist at interfaces, and we will present and discuss their possible atmospheric implications. Obviously, one of the largest interface is the sea-surface microlayer (SML), which is a region lying at the uppermost tens to hundreds of micrometres of the water surface, with physical, chemical and biological properties that differ from those of the underlying sub-surface water. Organic film formation at the sea surface is made possible in the presence of an excess of surface-active material. Hydrophobic surfactant films are typically believed to play the role of a physical barrier to air-sea exchanges, especially at low wind speed. We will show that dissolved organic matter (DOM) can trigger photochemistry at the air-sea interface, releasing unsaturated, functionalized volatile organic compounds (VOCs), including isoprene,... acting as precursors for the formation of organic aerosols, that were thought, up to now, to be solely of biological origin! In addition, we suggest that when arranged at an air/water interface, hydrophobic surfactant can have weak chemical interactions among them, which can trigger the absorption of sunlight and can consequently induce photochemistry at such interfaces. A major question arises from such observations, namely: can the existence of such weak intra- or intermolecular interactions and the subsequent photochemistry be generalized to many other atmospheric objects such as aerosols? This topic will be presented and discussed.

  4. Hurricane Frances as Observed by NASA's Spaceborne Atmospheric Infrared Sounder (AIRS) and SeaWinds

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This image shows Hurricane Frances as captured by instruments onboard two different satellites: the AIRS infrared instrument onboard Aqua, and the SeaWinds scatterometer onboard QuikSCAT. Both are JPL-managed instruments. AIRS data are used to create global three-dimensional maps of temperature, humidity and clouds, while scatterometers measure surface wind speed and direction over the ocean.

    The red vectors in the image show Frances' surface winds as measured by SeaWinds on QuikSCAT. The background colors show the temperature of clouds and surface as viewed in the infrared by AIRS, with cooler areas pushing to purple and warmer areas are pushing to red. The color scale on the right gives the temperatures in degrees Kelvin. (The top of the scale, 320 degrees Kelvin, corresponds to 117 degrees Fahrenheit, and the bottom, 180 degrees K is -135 degrees F.) The powerful circulation of this storm is evident from the combined data as well as the development of a clearly-defined central 'eye'. The infrared signal does not penetrate through clouds, so the light blue areas reveal the cold clouds tops associated with strong thunderstorms embedded within the storm. In cloud-free areas the infrared signal comes from Earth's surface, revealing warmer temperatures.

    The power of the SeaWinds scatterometer data set lies in its ability to generate global maps of wind speed and direction, giving us a snapshot of how the atmosphere is circulating. Weather prediction centers, including the Tropical Prediction Center - a branch of NOAA that monitors the creation of ocean-born storms, use scatterometer data to help it 'see' where these storms are brewing so that warnings can be issued and the storms, with often erratic motions, can be tracked.

    While the SeaWinds instrument isn't designed to gather hurricane data, having difficulty seeing the surface in heavy rain, it's data can be used in combination with other data sets to give us an insight into these storms. In

  5. Enhanced sea-air CO2 exchange influenced by a tropical depression in the South China Sea

    NASA Astrophysics Data System (ADS)

    Sun, Qingyang; Tang, DanLing; Legendre, Louis; Shi, Ping

    2014-10-01

    Ship measurements made 2 days after the passage of a tropical depression (TD) in the South China Sea (SCS, April 2011) showed two contrasted responses of the partial pressure of CO2 at sea surface (pCO2,sw). In low sea-surface salinity (SSS) water, pCO2,sw was low (349 ± 7 μatm), and the area was a carbon sink (-4.7 ± 1.8 mmol CO2 m-2 d-1), whereas in water with high SSS and chlorophyll a and low dissolved oxygen and sea surface temperature, pCO2,sw was higher than for normal SCS water (376 ± 8 versus 362 ± 4 μatm) and the area was a carbon source (1.2 ± 3.1 mmol CO2 m-2 d-1). Satellite data showed two large areas of low SSS before the TD, which were likely influenced by rainfall, and these areas were considered to have low pCO2,sw because of their low SSS. The high pCO2,sw after the TD is explained by the uplifting to the surface of deeper and CO2-rich water, due to winds accompanied by the TD. The difference in sea-air CO2 flux between the TD-affected area and the lower-SSS water was 1.99 + 4.70 = 6.7 mmol CO2 m-2 d-1, indicating a 100% change caused by the TD compared to the average seasonal value in spring in southern SCS (3.3 ± 0.3 mmol CO2 m-2 d-1). Undersaturation of CO2 prior to the TD due to dilution by freshwater and the preexisting cold eddy, and slow translation speed of the TD, are considered to account for the CO2 flux change.

  6. Analyses of global sea surface temperature 1856-1991

    NASA Astrophysics Data System (ADS)

    Kaplan, Alexey; Cane, Mark A.; Kushnir, Yochanan; Clement, Amy C.; Blumenthal, M. Benno; Rajagopalan, Balaji

    1998-08-01

    Global analyses of monthly sea surface temperature (SST) anomalies from 1856 to 1991 are produced using three statistically based methods: optimal smoothing (OS), the Kaiman filter (KF) and optimal interpolation (OI). Each of these is accompanied by estimates of the error covariance of the analyzed fields. The spatial covariance function these methods require is estimated from the available data; the timemarching model is a first-order autoregressive model again estimated from data. The data input for the analyses are monthly anomalies from the United Kingdom Meteorological Office historical sea surface temperature data set (MOHSST5) [Parker et al., 1994] of the Global Ocean Surface Temperature Atlas (GOSTA) [Bottomley et al., 1990]. These analyses are compared with each other, with GOSTA, and with an analysis generated by projection (P) onto a set of empirical orthogonal functions (as in Smith et al. [1996]). In theory, the quality of the analyses should rank in the order OS, KF, OI, P, and GOSTA. It is found that the first four give comparable results in the data-rich periods (1951-1991), but at times when data is sparse the first three differ significantly from P and GOSTA. At these times the latter two often have extreme and fluctuating values, prima facie evidence of error. The statistical schemes are also verified against data not used in any of the analyses (proxy records derived from corals and air temperature records from coastal and island stations). We also present evidence that the analysis error estimates are indeed indicative of the quality of the products. At most times the OS and KF products are close to the OI product, but at times of especially poor coverage their use of information from other times is advantageous. The methods appear to reconstruct the major features of the global SST field from very sparse data. Comparison with other indications of the El Niño-Southern Oscillation cycle show that the analyses provide usable information on

  7. Linking geomagnetic activity and polar surface air temperature variability

    NASA Astrophysics Data System (ADS)

    Seppala, Annika

    ERA-40 and ECMWF operational surface level air temperature (SAT) data sets from 1957 to 2006 were used to examine polar temperature variations during years with different levels of geomagnetic activity, as defined by the Ap index. Previous modelling work has suggested that NOx produced at high latitudes by energetic particle precipitation can eventually lead to detectable changes in polar SATs. We find that during winter months, ERA-40 and ECMWF polar SATs in years with high Ap index are different than in years with low Ap index; the differences are statistically significant at the 2-sigma level and range up to about ±4.5 K, de-pending on location. The temperature differences are larger when years with wintertime Sudden Stratospheric Warmings are excluded. Solar irradiance variations were taken into account in the analysis. Although using the re-analysis and operational data sets it was not possible to conclusively show that the polar SAT patterns are physically linked by geomagnetic activity, we conclude that geomagnetic activity likely plays a role in modulating polar wintertime surface air temperature patterns. The SAT results were tested against variation in the Quasi Biennial Oscillation (QBO), the El Niño Southern Oscillation (ENSO) and the Southern Annular Mode n (SAM). The results suggested that these were not driving the observed polar SAT variability. However, significant uncertainty is introduced by the Northern Annular Mode (NAM) and we could not robustly exclude a chance linkage between sea surface temperature (SST) variability and geomagnetic activity. Examining the physical link between geomagnetic activity and polar surface temperature variability patterns using atmospheric models is an ongoing task.

  8. 14 CFR 23.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine....

  9. 40 CFR 89.325 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air temperature... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 122 cm of the engine. The measurement location must be made...

  10. 40 CFR 89.325 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Engine intake air temperature... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 122 cm of the engine. The measurement location must be made...

  11. 14 CFR 23.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine....

  12. 14 CFR 23.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine....

  13. 40 CFR 89.325 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Engine intake air temperature... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 122 cm of the engine. The measurement location must be made...

  14. 40 CFR 89.325 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Engine intake air temperature... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 122 cm of the engine. The measurement location must be made...

  15. 40 CFR 89.325 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Engine intake air temperature... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 122 cm of the engine. The measurement location must be made...

  16. 14 CFR 23.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine....

  17. 14 CFR 23.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine....

  18. Research in Observations of Oceanic Air/Sea Interaction

    NASA Technical Reports Server (NTRS)

    Long, David G.; Arnold, David V.

    1995-01-01

    The primary purpose of this research has been: (1) to develop an innovative research radar scatterometer system capable of directly measuring both the radar backscatter and the small-scale and large-scale ocean wave field simultaneously and (2) deploy this instrument to collect data to support studies of air/sea interaction. The instrument has been successfully completed and deployed. The system deployment lasted for six months during 1995. Results to date suggest that the data is remarkably useful in air/sea interaction studies. While the data analysis is continuing, two journal and fifteen conference papers have been published. Six papers are currently in review with two additional journal papers scheduled for publication. Three Master's theses on this research have been completed. A Ph.D. student is currently finalizing his dissertation which should be completed by the end of the calendar year. We have received additional 'mainstream' funding from the NASA oceans branch to continue data analysis and instrument operations. We are actively pursuing results from the data expect additional publications to follow. This final report briefly describes the instrument system we developed and results to-date from the deployment. Additional detail is contained in the attached papers selected from the bibliography.

  19. A reconciliation of empirical and mechanistic models of the air-sea gas transfer velocity

    NASA Astrophysics Data System (ADS)

    Goddijn-Murphy, Lonneke; Woolf, David K.; Callaghan, Adrian H.; Nightingale, Philip D.; Shutler, Jamie D.

    2016-01-01

    Models of the air-sea transfer velocity of gases may be either empirical or mechanistic. Extrapolations of empirical models to an unmeasured gas or to another water temperature can be erroneous if the basis of that extrapolation is flawed. This issue is readily demonstrated for the most well-known empirical gas transfer velocity models where the influence of bubble-mediated transfer, which can vary between gases, is not explicitly accounted for. Mechanistic models are hindered by an incomplete knowledge of the mechanisms of air-sea gas transfer. We describe a hybrid model that incorporates a simple mechanistic view—strictly enforcing a distinction between direct and bubble-mediated transfer—but also uses parameterizations based on data from eddy flux measurements of dimethyl sulphide (DMS) to calibrate the model together with dual tracer results to evaluate the model. This model underpins simple algorithms that can be easily applied within schemes to calculate local, regional, or global air-sea fluxes of gases.

  20. The central role of diminishing sea ice in recent Arctic temperature amplification.

    PubMed

    Screen, James A; Simmonds, Ian

    2010-04-29

    The rise in Arctic near-surface air temperatures has been almost twice as large as the global average in recent decades-a feature known as 'Arctic amplification'. Increased concentrations of atmospheric greenhouse gases have driven Arctic and global average warming; however, the underlying causes of Arctic amplification remain uncertain. The roles of reductions in snow and sea ice cover and changes in atmospheric and oceanic circulation, cloud cover and water vapour are still matters of debate. A better understanding of the processes responsible for the recent amplified warming is essential for assessing the likelihood, and impacts, of future rapid Arctic warming and sea ice loss. Here we show that the Arctic warming is strongest at the surface during most of the year and is primarily consistent with reductions in sea ice cover. Changes in cloud cover, in contrast, have not contributed strongly to recent warming. Increases in atmospheric water vapour content, partly in response to reduced sea ice cover, may have enhanced warming in the lower part of the atmosphere during summer and early autumn. We conclude that diminishing sea ice has had a leading role in recent Arctic temperature amplification. The findings reinforce suggestions that strong positive ice-temperature feedbacks have emerged in the Arctic, increasing the chances of further rapid warming and sea ice loss, and will probably affect polar ecosystems, ice-sheet mass balance and human activities in the Arctic. PMID:20428168

  1. Tropical Cyclone Induced Air-Sea Interactions Over Oceanic Fronts

    NASA Astrophysics Data System (ADS)

    Shay, L. K.

    2012-12-01

    Recent severe tropical cyclones underscore the inherent importance of warm background ocean fronts and their interactions with the atmospheric boundary layer. Central to the question of heat and moisture fluxes, the amount of heat available to the tropical cyclone is predicated by the initial mixed layer depth and strength of the stratification that essentially set the level of entrainment mixing at the base of the mixed layer. In oceanic regimes where the ocean mixed layers are thin, shear-induced mixing tends to cool the upper ocean to form cold wakes which reduces the air-sea fluxes. This is an example of negative feedback. By contrast, in regimes where the ocean mixed layers are deep (usually along the western part of the gyres), warm water advection by the nearly steady currents reduces the levels of turbulent mixing by shear instabilities. As these strong near-inertial shears are arrested, more heat and moisture transfers are available through the enthalpy fluxes (typically 1 to 1.5 kW m-2) into the hurricane boundary layer. When tropical cyclones move into favorable or neutral atmospheric conditions, tropical cyclones have a tendency to rapidly intensify as observed over the Gulf of Mexico during Isidore and Lili in 2002, Katrina, Rita and Wilma in 2005, Dean and Felix in 2007 in the Caribbean Sea, and Earl in 2010 just north of the Caribbean Islands. To predict these tropical cyclone deepening (as well as weakening) cycles, coupled models must have ocean models with realistic ocean conditions and accurate air-sea and vertical mixing parameterizations. Thus, to constrain these models, having complete 3-D ocean profiles juxtaposed with atmospheric profiler measurements prior, during and subsequent to passage is an absolute necessity framed within regional scale satellite derived fields.

  2. Impact of air-sea interaction on East Asian summer monsoon climate in WRF

    NASA Astrophysics Data System (ADS)

    Kim, Eun-Jung; Hong, Song-You

    2010-10-01

    This study investigates the effects of air-sea interaction on the simulated East Asian summer monsoon (EASM) climate in a regional climate model. An ocean mixed layer model with a revised surface roughness length formulation that was originally designed for tropical cyclone simulation and a prognostic sea surface skin temperature scheme that considers the heat budget at the water surface are systematically evaluated on the monsoonal climate over East Asia for July 2006 in the regional Weather Research and Forecasting (WRF) model. Also, 9-year (2000-2008) June-August simulations are performed to evaluate the overall impacts of these three components on the simulated EASM climatology. The 1 month simulation for July 2006 reveals that the inclusion of the ocean mixed layer model cools the water surface due to enhanced mixing, in particular, when winds are strong. Such cooling is largely compensated by the inclusion of prognostic skin temperature since solar heating in daytime overwhelms the cooling in nighttime. The revised surface roughness length effectively reduces the surface heat flux by reducing the exchange coefficients, against the conventional Charnock formula. Consideration of the three components together results in the reduction of systemic biases of excessive precipitation and weakening of the North Pacific high in the summer climate from 2000 to 2008. It is concluded that the methodology designed in this study can be an efficient way to represent the air-sea interaction in regional atmospheric models for numerical weather prediction and climate simulation.

  3. OAFlux Satellite-Based High-Resolution Analysis of Air-Sea Turbulent Heat, Moisture, and Momentum Fluxes

    NASA Astrophysics Data System (ADS)

    Yu, Lisan

    2016-04-01

    The Objectively Analyzed air-sea Fluxes (OAFlux) project at the Woods Hole Oceanographic Institution has recently developed a new suite of products: the satellite-based high-resolution (HR) air-sea turbulent heat, moisture, and momentum fluxes over the global ocean from 1987 to the present. The OAFlux-HR fluxes are computed from the COARE bulk algorithm using air-sea variables (vector wind, near-surface humidity and temperature, and ocean surface temperature) derived from multiple satellite sensors and multiple missions. The vector wind time series are merged from 14 satellite sensors, including 4 scatterometers and 10 passive microwave radiometers. The near-surface humidity and temperature time series are retrieved from 11 satellite sensors, including 7 microwave imagers and 4 microwave sounders. The endeavor has greatly improved the depiction of the air-sea turbulent exchange on the frontal and meso-scales. The OAFlux-HR turbulent flux products are valuable datasets for a broad range of studies, including the study of the long-term change and variability in the oean-surface forcing functions, quantification of the large-scale budgets of mass, heat, and freshwater, and assessing the role of the ocean in the change and variability of the Earth's climate.

  4. Distributions and sea-to-air fluxes of nitrous oxide in the South China Sea and the West Philippines Sea

    NASA Astrophysics Data System (ADS)

    Tseng, Hsiao-Chun; Chen, Chen-Tung Arthur; Borges, Alberto V.; DelValls, T. Angel; Lai, Chao-Ming; Chen, Ting-Yu

    2016-09-01

    Approximately 600 water samples from the South China Sea (SCS) and 250 water samples from the West Philippines Sea (WPS) were collected during seven cruises from August 2003 to July 2007 to determine nitrous oxide (N2O) distributions between the surface and a maximum depth of 4250 m. In the SCS, the average surface N2O concentration exceeded the atmospheric equilibrium concentration (on average 132±23%); however in the WPS, the surface N2O concentration was lower than the atmospheric equilibrium concentration (on average 90±22%). The N2O concentration reached a maximum (~23 nmol L-1) in the WPS at 800-1000 m, and (~28 nmol L-1) at a shallower depth of around 600-800 m in the SCS, owing to vertical mixing and intensive upwelling in the SCS. In the SCS, the surface N2O concentration was 7.59±1.32 nmol L-1 and the calculated sea-to-air flux was 5.5±3.9 μmol m-2 d-1. The surface N2O concentration in the WPS, 5.19±1.26 nmol L-1, was lower than that in the SCS. The WPS is a sink for N2O and the calculated sea-to-air flux was -1.7±3.9 μmol m-2 d-1. The SCS emitted 19.3×106 mol d-1 N2O to the atmosphere and exported 8.5×106 mol d-1 N2O to the WPS during the wet season.

  5. Behavioral responses of Atlantic cod to sea temperature changes

    PubMed Central

    Freitas, Carla; Olsen, Esben Moland; Moland, Even; Ciannelli, Lorenzo; Knutsen, Halvor

    2015-01-01

    Understanding responses of marine species to temperature variability is essential to predict impacts of future climate change in the oceans. Most ectotherms are expected to adjust their behavior to avoid extreme temperatures and minimize acute changes in body temperature. However, measuring such behavioral plasticity in the wild is challenging. Combining 4 years of telemetry-derived behavioral data on juvenile and adult (30–80 cm) Atlantic cod (Gadus morhua), and in situ ocean temperature measurements, we found a significant effect of sea temperature on cod depth use and activity level in coastal Skagerrak. During summer, cod were found in deeper waters when sea surface temperature increased. Further, this effect of temperature was stronger on larger cod. Diel vertical migration, which consists in a nighttime rise to shallow feeding habitats, was stronger among smaller cod. As surface temperature increased beyond ∼15°C, their vertical migration was limited to deeper waters. In addition to larger diel vertical migrations, smaller cod were more active and travelled larger distances compared to larger specimens. Cold temperatures during winter tended, however, to reduce the magnitude of diel vertical migrations, as well as the activity level and distance moved by those smaller individuals. Our findings suggest that future and ongoing rises in sea surface temperature may increasingly deprive cod in this region from shallow feeding areas during summer, which may be detrimental for local populations of the species. PMID:26045957

  6. Sea Ice Surface Temperature Product from the Moderate Resolution Imaging Spectroradiometer (MODIS)

    NASA Technical Reports Server (NTRS)

    Hall, Dorothy K.; Key, Jeffrey R.; Casey, Kimberly A.; Riggs, George A.; Cavalieri, Donald J.

    2003-01-01

    Global sea ice products are produced from the Earth Observing System (EOS) Moderate Resolution Imaging Spectroradiometer (MODIS) on board both the Terra and Aqua satellites. Daily sea ice extent and ice-surface temperature (IST) products are available at 1- and 4-km resolution. Validation activities have been undertaken to assess the accuracy of the MODIS IST product at the South Pole station in Antarctica and in the Arctic Ocean using near-surface air-temperature data from a meteorological station and drifting buoys. Results from the study areas show that under clear skies, the MODIS ISTs are very close to those of the near-surface air temperatures with a bias of -1.1 and -1.2 K, and an uncertainty of 1.6 and 1.7 K, respectively. It is shown that the uncertainties would be reduced if the actual temperature of the ice surface were reported instead of the near-surface air temperature. It is not possible to get an accurate IST from MODIS in the presence of even very thin clouds or fog, however using both the Advanced Microwave Scanning Radiometer-EOS (AMSR-E) and the MODIS on the Aqua satellite, it may be possible to develop a relationship between MODIS-derived IST and ice temperature derived from the AMSR-E. Since the AMSR-E measurements are generally unaffected by cloud cover, they may be used to complement the MODIS IST measurements.

  7. Covariation of Mesoscale Ocean Color and Sea-Surface Temperature Patterns in the Sargasso Sea

    NASA Technical Reports Server (NTRS)

    McGillicuddy, D. J.; Kosnyrev, V. K.; Ryan, J. P.; Yoder, J. A.

    2001-01-01

    During the lifetime of the Coastal Zone Color Scanner, there were 21 instances in which both satellite-derived ocean color and sea-surface temperature are simultaneously available over large areas of the Sargasso Sea. These images reveal close correspondence between mesoscale structures observed in temperature and pigment fields. In general, higher (lower) pigment biomass occurs in mesoscale features consisting of cold (warm) temperature anomalies. This relationship is consistent with the idea that upward displacement of isopycnals at the base of the euphotic zone by mesoscale eddies is an important mechanism of nutrient supply in the region.

  8. Enhanced Sea Ice Concentration and Ice Temperature Algorithms for AMSR

    NASA Technical Reports Server (NTRS)

    Comiso, Josefino C.; Manning, Will; Gersten, Robert

    1998-01-01

    Accurate quantification of sea ice concentration and ice temperature from satellite passive microwave data is important because they provide the only long term, spatially detailed and consistent data set needed to study the climatology of the polar regions. Sea ice concentration data are used to derive large-scale daily ice extents that are utilized in trend analysis of the global sea ice cover. They are also used to quantify the amount of open water and thin ice in polynya and divergence regions which together with ice temperatures are in turn needed to estimate vertical heat and salinity fluxes in these regions. Sea ice concentrations have been derived from the NASA Team and Bootstrap algorithms while a separate technique for deriving ice temperature has been reported. An integrated technique that will utilizes most of the channels of AMSR (Advanced Microwave Scanning Radiometer) has been developed. The technique uses data from the 6 GHz and 37 GHz channels at vertical polarization obtain an initial estimate of sea ice concentration and ice temperature. The derived ice temperature is then utilized to estimate the emissivities for the corresponding observations at all the other channels. A procedure for calculating the ice concentration similar to the Bootstrap technique is then used but with variables being emissivities instead of brightness temperatures to minimizes errors associated with spatial changes in ice temperatures within the ice pack. Comparative studies of ice concentration results with those from other algorithms, including the original Bootstrap algorithm and those from high resolution satellite visible and infrared data will be presented. Also, results from a simulation study that demonstrates the effectiveness of the technique in correcting for spatial variations in ice temperatures will be shown. The ice temperature results are likewise compared with satellite infrared and buoy data with the latter adjusted to account for the effects of the snow

  9. Breaking waves and near-surface sea spray aerosol dependence on changing winds: Wave breaking efficiency and bubble-related air-sea interaction processes

    NASA Astrophysics Data System (ADS)

    Hwang, P. A.; Savelyev, I. B.; Anguelova, M. D.

    2016-05-01

    Simultaneous measurements of sea spray aerosol (SSA), wind, wave, and microwave brightness temperature are obtained in the open ocean on-board Floating Instrument Platform (FLIP). These data are analysed to clarify the ocean surface processes important to SSA production. Parameters are formulated to represent surface processes with characteristic length scales spanning a broad range. The investigation reveals distinct differences of the SSA properties in rising winds and falling winds, with higher SSA volume in falling winds. Also, in closely related measurements of whitecap coverage, higher whitecap fraction as a function of wind speed is found in falling winds than in rising winds or in older seas than in younger seas. Similar trend is found in the short scale roughness reflected in the microwave brightness temperature data. In the research of length and velocity scales of breaking waves, it has been observed that the length scale of wave breaking is shorter in mixed seas than in wind seas. For example, source function analysis of short surface waves shows that the characteristic length scale of the dissipation function shifts toward higher wavenumber (shorter wavelength) in mixed seas than in wind seas. Similarly, results from feature tracking or Doppler analysis of microwave radar sea spikes, which are closely associated with breaking waves, show that the magnitude of the average breaking wave velocity is smaller in mixed seas than in wind seas. Furthermore, breaking waves are observed to possess geometric similarity. Applying the results of breaking wave analyses to the SSA and whitecap observations described above, it is suggestive that larger air cavities resulting from the longer breakers are entrained in rising high winds. The larger air cavities escape rapidly due to buoyancy before they can be fully broken down into small bubbles for the subsequent SSA production or whitecap manifestation. In contrast, in falling winds (with mixed seas more likely), the

  10. Air temperature variation across the seed cotton dryer mixpoint

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eighteen tests were conducted in six gins in the fall of 2008 to measure air temperature variation within various heated air seed cotton drying systems with the purpose of: checking validation of recommendations by a professional engineering society and measuring air temperature variation across the...

  11. Possible Economies in Air-Conditioning by Accepting Temperature Swings.

    ERIC Educational Resources Information Center

    Loudon, A. G.; Petherbridge, P.

    Public building air conditioning systems, which use constant and varying heat and cooling loads, are compared and investigated. Experiments indicated that constant temperature controls based on outside air temperature alone were inefficient. Ventilating a building with outside air and the methods of doing so are cited as being the most economical…

  12. 14 CFR 29.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  13. 14 CFR 25.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  14. 14 CFR 25.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  15. 14 CFR 29.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  16. 14 CFR 29.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  17. 14 CFR 29.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  18. 14 CFR 25.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  19. 14 CFR 25.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  20. 14 CFR 29.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  1. 14 CFR 25.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  2. AIR TEMPERATURE DISTRIBUTION IN SEED COTTON DRYING SYSTEMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ten tests were conducted in the fall of 2007 to measure air temperature variation within various heated air seed cotton drying systems with the purpose of: checking validation of recommendations by a professional engineering society and measuring air temperature variation across the airflow ductwork...

  3. Acoustic method for measuring air temperature and humidity in rooms

    NASA Astrophysics Data System (ADS)

    Kanev, N. G.

    2014-05-01

    A method is proposed to determine air temperature and humidity in rooms with a system of sound sources and receivers, making it possible to find the sound velocity and reverberation time. Nomograms for determining the air temperature and relative air humidity are constructed from the found sound velocity and time reverberation values. The required accuracy of measuring these parameters is estimated.

  4. Three modes of interdecadal trends in sea surface temperature and sea surface height

    NASA Astrophysics Data System (ADS)

    Gnanadesikan, A.; Pradal, M.

    2013-12-01

    It might be thought that sea surface height and sea surface temperature would be tightly related. We show that this is not necessarily the case on a global scale. We analysed this relationship in a suite of coupled climate models run under 1860 forcing conditions. The models are low-resolution variants of the GFDL Earth System Model, reported in Galbraith et al. (J. Clim. 2011). 1. Correlated changes in global sea surface height and global sea surface temperature. This mode corresponds to opening and closing of convective chimneys in the Southern Ocean. As the Southern Ocean destratifies, sea ice formation is suppressed during the winter and more heat is taken up during the summer. This mode of variability is highly correlated with changes in the top of the atmosphere radiative budget and weakly correlated with changes in the deep ocean circulation. 2. Uncorrelated changes in global sea surface height and global sea surface temperature. This mode of variability is associated with interdecadal variabliity in tropical winds. Changes in the advective flux of heat to the surface ocean play a critical role in driving these changes, which also result in significant local changes in sea level. Changes sea ice over the Southern Ocean still result in changes in solar absorption, but these are now largely cancelled by changes in outgoing longwave radiation. 3. Anticorrelated changes in global sea surface height and global sea surface temperatures. By varying the lateral diffusion coefficient in the ocean model, we are able to enhance and suppress convection in the Southern and Northern Pacific Oceans. Increasing the lateral diffusion coefficients shifts the balance sources of deep water away from the warm salty deep water of the North Atlantic and towards cold fresh deep water from the other two regions. As a result, even though the planet as a whole warms, the deep ocean cools and sea level falls, with changes of order 30 cm over 500 years. The increase in solar absorption

  5. The interannual oscillation of sea surface temperature in the South China Sea

    SciTech Connect

    Zhou Faxiu; Yu Shenyu; Fu Gang; Wang Dongxiao

    1994-12-31

    The South China Sea (SCS) is located in the area of the Asia monsoons and is a quasi-closed deep basin near the tropical western Pacific. The sea surface temperature anomalies (SSTA) in the South China Sea have an influence on the precipitation in flood season in the South China. The anomalies of the Asia monsoons have great effect on SST in the SCS. This paper aims at finding the features of the interannual oscillation of SST and discussing the mechanism of the SST oscillation in the SCS.

  6. Impacts of Air-Sea Interaction on Tropical Cyclone Track and Intensity

    NASA Technical Reports Server (NTRS)

    Wu, Liguang; Wang, Bin; Braun, Scott A.

    2004-01-01

    The influence of hurricane-ocean coupling on intensity and track of tropical cyclones (TCs) is investigated through idealized numerical experiments using a coupled hurricane-ocean model. The focus is placed on how air-sea interaction affects TC tracks and intensity. It is found that the symmetric sea surface temperature (SST) cooling is primarily responsible for the TC weakening in the coupled experiments because the induced asymmetric circulation associated with the asymmetric SST anomalies is weak and shallow. The track difference between the coupled and fixed SST experiments is generally small because of the competing processes. One is associated with the modified TC asymmetries. The asymmetric SST anomalies - weaken the surface fluxes in the rear and enhance the fluxes in the front. As a result, the enhanced diabatic heating is located on the southern side for a westward-moving TC, tending to shift the TC southward. The symmetric SST anomalies weakens the TC intensity and thus the dymmetrization process, leading to more prominent TC asymmetries. The other is associated with the weakening of the beta drift resulting from the weakening of the TC outer strength. In the coupled experiment, the weakening of the beta drift leads to a more northward shift. By adjusting the vortex outer strength of the initial vortices, the beta drift can vary while the effect of air-sea interaction changes little. Two types of track differences simulated in the previous numerical studies are obtained.

  7. Air-sea interaction during an extreme cold air outbreak from the eastern coast of the United States

    NASA Technical Reports Server (NTRS)

    Grossman, Robert L.; Betts, Alan K.

    1990-01-01

    An aircraft investigation of boundary layer mean and turbulent structure is reported, and the Lagrangian budgets of temperature and moisture in the subcloud layer following a streamline during an extreme cold air outbreak are evaluated. The maximum sea-air temperature difference was 23 K. Two aircraft were used: the NCAR Electra, which measured turbulent fluxes and investigated subcloud layer conditions, and the NASA Electra, which measured the height of cloud tops using lidar. A stratocumulus overcast was found from about 60 km offshore to the Gulf Stream core with cloud top rising downstream. East of the Gulf Stream cumulus congestus and snow showers were observed. Cloud base decreased downstream and numerous steam plumes filled the subcloud layer. Temperature cross sections show most warming, and moistening of the subcloud layer occurred before the Gulf Stream core. Windspeeds increased downstream and maxima were observed near cloud top (inversion) and in the subcloud layer. Lagrangian budgets showed most warming, and moistening of the layer between 70 m and about 100 m below mean cloud base was due to turbulent flux divergence.

  8. The EUSTACE project: delivering global, daily information on surface air temperature

    NASA Astrophysics Data System (ADS)

    Morice, C. P.; Rayner, N. A.; Auchmann, R.; Bessembinder, J.; Bronnimann, S.; Brugnara, Y.; Conway, E. A.; Ghent, D.; Good, E.; Herring, K.; Kennedy, J.; Lindgren, F.; Madsen, K. S.; Merchant, C. J.; van der Schrier, G.; Stephens, A.; Tonboe, R. T.; Waterfall, A. M.; Mitchelson, J.; Woolway, I.

    2015-12-01

    Day-to-day variations in surface air temperature affect society in many ways; however, daily surface air temperature measurements are not available everywhere. A global daily analysis cannot be achieved with measurements made in situ alone, so incorporation of satellite retrievals is needed. To achieve this, we must develop an understanding of the relationships between traditional (land and marine) surface air temperature measurements and retrievals of surface skin temperature from satellite measurements, i.e. Land Surface Temperature, Ice Surface Temperature, Sea Surface Temperature and Lake Surface Water Temperature. These relationships can be derived either empirically or with the help of a physical model.Here we discuss the science needed to produce a fully-global daily analysis (or ensemble of analyses) of surface air temperature on the centennial scale, integrating different ground-based and satellite-borne data types. Information contained in the satellite retrievals would be used to create globally-complete fields in the past, using statistical models of how surface air temperature varies in a connected way from place to place. As the data volumes involved are considerable, such work needs to include development of new "Big Data" analysis methods.We will present plans and progress along this road in the EUSTACE project (2015-June 2018), i.e.: • providing new, consistent, multi-component estimates of uncertainty in surface skin temperature retrievals from satellites; • identifying inhomogeneities in daily surface air temperature measurement series from weather stations and correcting for these over Europe; • estimating surface air temperature over all surfaces of Earth from surface skin temperature retrievals; • using new statistical techniques to provide information on higher spatial and temporal scales than currently available, making optimum use of information in data-rich eras.Information will also be given on how interested users can become

  9. 40 CFR 90.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air temperature... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...) The temperature measurements must be accurate to within ±2 °C....

  10. 40 CFR 90.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Engine intake air temperature... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...) The temperature measurements must be accurate to within ±2 °C....

  11. 40 CFR 90.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Engine intake air temperature... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...) The temperature measurements must be accurate to within ±2 °C....

  12. 40 CFR 90.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Engine intake air temperature... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...) The temperature measurements must be accurate to within ±2 °C....

  13. 40 CFR 90.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Engine intake air temperature... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...) The temperature measurements must be accurate to within ±2 °C....

  14. Modes of variability of global sea surface temperature, free atmosphere temperature and oceanic surface energy flux

    SciTech Connect

    Hu, Wenjie; Newell, R.E.; Wu, Zhong-Xiang

    1994-11-01

    Monthly mean sea surface temperature (SST), free air temperature from satellite microwave sounding units (MSU) and oceanic surface energy fluxes are subjected to empirical orthogonal function (EOF) analysis for a common decade to investigate the physical relationships involved. The first seasonal modes of surface solar energy flux and SST show similar inter-hemispheric patterns with an annual cycle. Solar flux appears to control this pattern of SST. The first seasonal mode of MSU is similar with, additionally, land-sea differences; MSU is apparently partly controlled by absorption of solar near-infrared radiation and partly by sensible heat from from the land surface. The second and third seasonal eigenvector of SST and solar flux exhibit semi-annual oscillations associated with a pattern of cloudiness in the subtropics accompanying the translation of the Hadley cell rising motion between the hemispheres. The second seasonal mode of MSU is dominated by an El Nino Signal. The first nonseasonal EOFs of SST and solar flux exhibit El Nino characteristics with solar pattern being governed by west-to-east translation of a Walker cell type pattern. The first non-seasonal EOF of MSU shows a tropical strip pattern for the El Nino mode, which is well correlated with the latent heat fluxes in the tropical east Pacific but not in the tropical west Pacific. Two possible explanations are: an increase in subsidence throughout the tropical strip driven by extra evaporation in the tropical east Pacific and consequent additional latent heat liberation; a decrease of meridional heat flux out of the tropics. 56 refs., 12 figs., 5 tabs.

  15. Sea-air carbon dioxide fluxes along 35°S in the South Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Lencina-Avila, J. M.; Ito, R. G.; Garcia, C. A. E.; Tavano, V. M.

    2016-09-01

    The oceans play an important role in absorbing a significant fraction of the atmospheric CO2 surplus, but there are still uncertainties concerning several open ocean regions, such as the under-sampled South Atlantic Ocean. This study assessed the net sea-air CO2 fluxes and distribution of sea-surface CO2 fugacity (f C O2sw) along the 35°S latitude in the South Atlantic, during 2011 spring and early summer periods. Underway CO2 molar fraction, temperature, salinity and dissolved oxygen measurements were taken continuously from South American to South African continental shelves. Values of both satellite and discrete in situ chlorophyll-a concentration along the ship's track were used as ancillary data. Both f C O2sw and difference in sea-air fugacity (ΔfCO2) showed high variability along the cruise track, with higher values found on the continental shelf and slope regions. All ΔfCO2 values were negative, implying that a sinking process was occurring during the cruise period, with an average net CO2 flux of -3.1±2.2 mmol CO2 m-2 day-1 (using Wanninkhof, 1992). Physical variables were the main drivers of f C O2sw variability in South American continental shelf and open ocean regions, while the biological factor dominated the South African continental shelf. Algorithms for estimating fCO2 and temperature-normalized fCO2 were developed and applied separately to the three defined sub-regions: the South American shelf, the open ocean and the South African continental shelf, with the regional temperature-normalized fCO2 models showing better results.

  16. Radar Backscatter Across the Gulf Stream Sea Surface Temperature Front

    NASA Technical Reports Server (NTRS)

    Nghiem, S. V.; Li, F. K.; Walsh, E. J.; Lou, S. H.

    1998-01-01

    Ocean backscatter signatures were measured by the Jet Propulsion Laboratory airborne NUSCAT K(sub u)-band scatterometer across the Gulf Stream sea surface temperature front. The measurements were made during the Surface Wave Dynamics Experiment (SWADE) off the coast of Virginia and Maryland in the winter of 1991.

  17. Concerns--High Sea Levels and Temperatures Seen Next Century.

    ERIC Educational Resources Information Center

    Ryan, Paul R.

    1984-01-01

    A National Research Council committee recently concluded that atmospheric carbon dioxide levels will "most likely" double by late in the next century, causing an increase in the earth's average temperature. Effects of the increase on sea levels, global climate, and other parameters are discussed. (JN)

  18. Three-way partitioning of sea surface temperature measurement error

    NASA Technical Reports Server (NTRS)

    Chelton, D.

    1983-01-01

    Given any set of three 2 degree binned anomaly sea surface temperature (SST) data sets by three different sensors, estimates of the mean square error of each sensor estimate is made. The above formalism performed on every possible triplet of sensors. A separate table of error estimates is then constructed for each sensor.

  19. Simulated sea surface temperature and heat fluxes in different climates of the Baltic Sea.

    PubMed

    Döscher, Ralf; Meier, H E Markus

    2004-06-01

    The physical state of the Baltic Sea in possible future climates is approached by numerical model experiments with a regional coupled ocean-atmosphere model driven by different global simulations. Scenarios and recent climate simulations are compared to estimate changes. The sea surface is clearly warmer by 2.9 degrees C in the ensemble mean. The horizontal pattern of average annual mean warming can largely be explained in terms of ice-cover reduction. The transfer of heat from the atmosphere to the Baltic Sea shows a changed seasonal cycle: a reduced heat loss in fall, increased heat uptake in spring, and reduced heat uptake in summer. The interannual variability of surface temperature is generally increased. This is associated with a smoothed frequency distribution in northern basins. The overall heat budget shows increased solar radiation to the sea surface, which is balanced by changes of the other heat flux components. PMID:15264603

  20. Changes in sea-ice cover and temperature in the Western Ross Sea during the Holocene

    NASA Astrophysics Data System (ADS)

    Fleury, Sophie; Kim, Jung-Hyun; Gal, Jong-Ku; Mezgec, Karin; Belt, Simon; Smik, Lukas; Stenni, Barbara; Melis, Romana; Crosta, Xavier; Shin, Kyung-Hoon

    2016-04-01

    Although changes in sea-ice cover contribute to global climatic variations, they are poorly constrained for periods earlier than the last decades. More records are especially required around Antarctica, where the formation of Antarctic Bottom Waters participates to global thermohaline circulation. However, this region provided only a few marine sediment cores spanning the entire Holocene, especially because of generally low sedimentation rates. This study focuses on marine sediment core ANTA99-CJ5 (73°49'S; 175°39'E), located in the open sea ice zone (OSIZ) of the western Ross Sea. We analyzed several lipid biomarkers: highly branched isoprenoids (HBIs), sterols, diols and GDGTs. The combination of several biomarkers and the comparison of these results with a diatom record previously published on the same core enabled us to trace past changes in temperatures as well as in sea-ice condition over the last 11,600 years.

  1. Japanese Whaling Ships' Sea Surface Temperatures 1946-84.

    NASA Astrophysics Data System (ADS)

    Mierzejewska, Anna W.; Wu, Zhongxiang; Newell, Reginald E.; Miyashita, Tomio

    1997-03-01

    Japanese whaling ship data, a homogeneous dataset mainly covering the southern high-latitude oceans, may be used to fill in gaps in recent sea surface temperature datasets, contributing a fair number of additional observations in this area. The Japanese whaling ship data are treated separately here for the period 1946-84, and they show no significant temperature changes during this period in the main fishing region of 60°-70°S or in the west Pacific warm pool.

  2. Air-sea exchange of gaseous mercury in the East China Sea.

    PubMed

    Wang, Chunjie; Ci, Zhijia; Wang, Zhangwei; Zhang, Xiaoshan

    2016-05-01

    Two oceanographic cruises were carried out in the East China Sea (ECS) during the summer and fall of 2013. The main objectives of this study are to identify the spatial-temporal distributions of gaseous elemental mercury (GEM) in air and dissolved gaseous mercury (DGM) in surface seawater, and then to estimate the Hg(0) flux. The GEM concentration was lower in summer (1.61 ± 0.32 ng m(-3)) than in fall (2.20 ± 0.58 ng m(-3)). The back-trajectory analysis revealed that the air masses with high GEM levels during fall largely originated from the land, while the air masses with low GEM levels during summer primarily originated from ocean. The spatial distribution patterns of total Hg (THg), fluorescence, and turbidity were consistent with the pattern of DGM with high levels in the nearshore area and low levels in the open sea. Additionally, the levels of percentage of DGM to THg (%DGM) were higher in the open sea than in the nearshore area, which was consistent with the previous studies. The THg concentration in fall was higher (1.47 ± 0.51 ng l(-1)) than those of other open oceans. The DGM concentration (60.1 ± 17.6 pg l(-1)) and Hg(0) flux (4.6 ± 3.6 ng m(-2) h(-1)) in summer were higher than those in fall (DGM: 49.6 ± 12.5 pg l(-1) and Hg(0) flux: 3.6 ± 2.8 ng m(-2) h(-1)). The emission flux of Hg(0) from the ECS was estimated to be 27.6 tons yr(-1), accounting for ∼0.98% of the global Hg oceanic evasion though the ECS only accounts for ∼0.21% of global ocean area, indicating that the ECS plays an important role in the oceanic Hg cycle. PMID:26975003

  3. Sea surface temperature modelling in the Sea of Iroise: assessment of boundary conditions

    NASA Astrophysics Data System (ADS)

    Guillou, Nicolas; Chapalain, Georges; Duvieilbourg, Eric

    2013-07-01

    The present study investigates the sensitivity of the COupled Hydrodynamical-Ecological model for REgioNal and Shelf seas (COHERENS) to predict sea surface temperature (SST) patterns in the Sea of Iroise (western end of French Brittany) in relation to the spatial and temporal resolutions of open boundary conditions (OBCs). Two sources of daily operational OBCs of temperature are considered, derived from (1) the Mercator Global Ocean and (2) the Iberian Biscay Irish analysis and forecasting systems delivering predictions at spatial resolutions of 1/12° and 1/36°, respectively. Coastal model performance is evaluated by comparing SST predictions with recently available field data collected (1) along the route of a vessel travelling between the coast and the isle of Ushant and (2) at two offshore stations. The comparison is extended to SST spatial distribution derived from remote-sensing observations. The influence of OBC spatial resolution is exhibited in the north-eastern area of the Sea of Iroise in relation to the intrusion of cold surface waters. OBC temporal resolution is found to have a lower impact advocating for the implementation of climatological temperature forcings to predict major SST patterns in the Sea of Iroise.

  4. Model study on the dependence of primary marine aerosol emission on the sea surface temperature

    NASA Astrophysics Data System (ADS)

    Barthel, S.; Tegen, I.; Wolke, R.; van Pinxteren, M.

    2014-01-01

    Primary marine aerosol composed of sea salt and organic material is an important contributor to the global aerosol load. By comparing measurements from two EMEP (co-operative programme for monitoring and evaluation of the long-range transmissions of air-pollutants in Europe) intensive campaigns in June 2006 and January 2007 with results from an atmospheric transport model this work shows that accounting for the influence of the sea surface temperature on the emission of primary marine aerosol improves the model results towards the measurements in both months. Different sea surface temperature dependencies were evaluated. Using correction functions based on Sofiev et al. (2011) and Jaeglé et al. (2011) improves the model results for coarse mode particles. In contrast, for the fine mode aerosols no best correction function could be found. The model captures the low sodium concentrations at the marine station Virolahti II (Finland), which is influenced by air masses from the low salinity Baltic Sea, as well as the higher concentrations at Cabauw (Netherlands) and Auchencorth Moss (Scotland). These results indicate a shift towards smaller sizes with lower salinity for the emission of dry sea salt aerosols. Organic material was simulated as part of primary marine aerosol assuming an internal mixture with sea salt. A comparison of the model results for primary organic carbon with measurements by a Berner-impactor at Sao Vincente (Cape Verde) indicated that the model underpredicted the observed organic carbon concentration. This leads to the conclusion that the formation of secondary organic material needs to be included in the model to improve the agreement with the measurements.

  5. Annual and seasonal fCO2 and air-sea CO2 fluxes in the Barents Sea

    NASA Astrophysics Data System (ADS)

    Lauvset, S. K.; Chierici, M.; Counillon, F.; Omar, A.; Nondal, G.; Johannessen, T.; Olsen, A.

    2013-03-01

    The Barents Sea is the strongest CO2 sink in the Arctic region, yet estimates of the air-sea CO2 flux in this area show a large span reflecting uncertainty as well as significant variability both seasonally and regionally. Here we use a previously unpublished data set of seawater CO2 fugacity (fCO2), and map these data over the western Barents Sea through multivariable linear regressions with SeaWiFS/MODIS remote sensing and TOPAZ model data fields. We find that two algorithms are necessary in order to cover the full seasonal cycle, mainly because not all proxy variables are available for the entire year, and because variability in fCO2 is driven by different mechanisms in summer and winter. A comprehensive skill assessment indicates that there is a good overall correspondence between observations and predictions. The algorithms are also validated using two independent data sets, with good results. The gridded fCO2 fields reveal tight links between water mass distribution and fCO2 in all months, and particularly in winter. The seasonal cycle show peaks in the total air-sea CO2 influx in May and September, caused by respectively biological drawdown of CO2 and low sea ice concentration leaving a large open water area. For 2007 the annual average air-sea CO2 flux is - 48 ± 5 gC m- 2, which is comparable to previous estimates.

  6. Accuracy of sea ice temperature derived from the advanced very high resolution radiometer

    NASA Technical Reports Server (NTRS)

    Yu, Y.; Rothrock, D. A.; Lindsay, R. W.

    1995-01-01

    The accuracy of Arctic sea ice surface temperatures T(sub s) dericed from advanced very high resolution radiometer (AVHRR) thermal channels is evaluated in the cold seasons by comparing them with surface air temperatures T(sub air) from drifting buoys and ice stations. We use three different estimates of satellite surface temperatures, a direct estimate from AVHRR channel 4 with only correction for the snow surface emissivity but not for the atmosphere, a single-channel regression of T(sub s) with T(sub air), and Key and Haefliger's (1992) polar multichannel algorithm. We find no measurable bias in any of these estimates and few differences in their statistics. The similar performance of all three methods indicates that an atmospheric water vapor correction is not important for the dry winter atmosphere in the central Arctic, given the other sources of error that remain in both the satellite and the comparison data. A record of drifting station data shows winter air temperature to be 1.4 C warmer than the snow surface temperature. `Correcting' air temperatures to skin temperature by subtracting this amount implies that satellite T(sub s) estimates are biased warm with respect to skin temperature by about this amount. A case study with low-flying aircraft data suggests that ice crystal precipitation can cause satellite estimates of T(sub s) to be several degrees warmer than radiometric measurements taken close to the surface, presumably below the ice crystal precipitation layer. An analysis in which errors are assumed to exist in all measurements, not just the satellite measurements, gives a standard deviation in the satellite estimates of 0.9 C, about half the standard deviation of 1.7 C estimated by assigning all the variation between T(sub s) and T(sub air) to errors in T(sub s).

  7. Labrador Sea surface temperature control on the summer weather in the Eastern Europe

    NASA Astrophysics Data System (ADS)

    Gnatiuk, Natalia; Vihma, Timo; Bobylev, Leonid

    2016-04-01

    Many studies have addressed the linkages between the Arctic Amplification and mid-latitude weather patterns. Most of them have focused on the effects of changes in sea ice, terrestrial snow or open ocean SST on the air temperature in selected mid-latitude areas. However, when analysing such potential linkages, one should be aware that from the point of view of the atmosphere it is almost the same whether the thermal forcing originates from the sea ice melt, snowmelt, or changes in SST. Most important is to quantify how the atmosphere responds to anomalies in the surface temperature and then affects weather patterns in remote areas. For this purpose, we studied the hemispheric-scale relationships between anomalies in the Northern Hemisphere Earth surface temperature (Ts) and 2-m air temperature (T2m) in mid-latitudes (Central and Eastern Europe). Using regression analyses based on the ERA-Interim reanalysis data, we assessed the said temperature relationships with focus on the lagged monthly and inter-seasonal linkages. Technically we divided the Northern Hemisphere in equal areas with a size of 15x10 degrees and calculated correlation coefficients for the monthly mean temperatures between all defined regions from one side and the Central/East European study regions from another side over the period 1979-2014. Using this approach, we found that the strongest links in the considered kind of relationships take place between spring sea surface temperature in the Labrador Sea and summer air (T2m) temperature in the Eastern Europe. In order to confirm the correlation results obtained, to identify thermal forcing factors and to assess their relative importance, we analysed the multiyear averages and anomalies of various meteorological parameters for 10 coldest and 10 warmest springs and summers in the period 1979-2014: surface pressure, total precipitation, sea-ice and total cloud cover, wind components, surface solar radiation downwards, surface heat fluxes and air

  8. Sea surface carbon dioxide at the Georgia time series site (2006-2007): Air-sea flux and controlling processes

    NASA Astrophysics Data System (ADS)

    Xue, Liang; Cai, Wei-Jun; Hu, Xinping; Sabine, Christopher; Jones, Stacy; Sutton, Adrienne J.; Jiang, Li-Qing; Reimer, Janet J.

    2016-01-01

    Carbon dioxide partial pressure (pCO2) in surface seawater was continuously recorded every three hours from 18 July 2006 through 31 October 2007 using a moored autonomous pCO2 (MAPCO2) system deployed on the Gray's Reef buoy off the coast of Georgia, USA. Surface water pCO2 (average 373 ± 52 μatm) showed a clear seasonal pattern, undersaturated with respect to the atmosphere in cold months and generally oversaturated in warm months. High temporal resolution observations revealed important events not captured in previous ship-based observations, such as sporadically occurring biological CO2 uptake during April-June 2007. In addition to a qualitative analysis of the primary drivers of pCO2 variability based on property regressions, we quantified contributions of temperature, air-sea exchange, mixing, and biological processes to monthly pCO2 variations using a 1-D mass budget model. Although temperature played a dominant role in the annual cycle of pCO2, river inputs especially in the wet season, biological respiration in peak summer, and biological production during April-June 2007 also substantially influenced seawater pCO2. Furthermore, sea surface pCO2 was higher in September-October 2007 than in September-October 2006, associated with increased river inputs in fall 2007. On an annual basis this site was a moderate atmospheric CO2 sink, and was autotrophic as revealed by monthly mean net community production (NCP) in the mixed layer. If the sporadic short productive events during April-May 2007 were missed by the sampling schedule, one would conclude erroneously that the site is heterotrophic. While previous ship-based pCO2 data collected around this buoy site agreed with the buoy CO2 data on seasonal scales, high resolution buoy observations revealed that the cruise-based surveys undersampled temporal variability in coastal waters, which could greatly bias the estimates of air-sea CO2 fluxes or annual NCP, and even produce contradictory results.

  9. Sea surface temperature of the coastal zones of France

    NASA Technical Reports Server (NTRS)

    Deschamps, P. Y.; Crepon, M.; Monget, J. M.; Verger, F. (Principal Investigator); Frouin, R.; Cassanet, J.; Wald, L.

    1982-01-01

    Thermal gradients in French coastal zones for the period of one year were mapped in order to enable a coherent study of certain oceanic features detectable by the variations in the sea surface temperature field and their evolution in time. The phenomena examined were mesoscale thermal features in the English Channel, the Bay of Biscay, and the northwestern Mediterranean; thermal gradients generated by French estuary systems; and diurnal heating in the sea surface layer. The investigation was based on Heat Capacity Mapping Mission imagery.

  10. Biological control of surface temperature in the Arabian Sea

    NASA Technical Reports Server (NTRS)

    Sathyendranath, Shubha; Gouveia, Albert D.; Shetye, Satish R.; Ravindran, P.; Platt, Trevor

    1991-01-01

    In the Arabian Sea, the southwest monsoon promotes seasonal upwelling of deep water, which supplies nutrients to the surface layer and leads to a marked increase in phytoplankton growth. Remotely sensed data on ocean color are used here to show that the resulting distribution of phytoplankton exerts a controlling influence on the seasonal evolution of sea surface temperature. This results in a corresponding modification of ocean-atmosphere heat exchange on regional and seasonal scales. It is shown that this biological mechanism may provide an important regulating influence on ocean-atmosphere interactions.

  11. Model estimating the effect of marginal ice zone processes on the phytoplankton primary production and air-sea flux of CO2 in the Barents Sea

    NASA Astrophysics Data System (ADS)

    Dvornikov, Anton; Sein, Dmitry; Ryabchenko, Vladimir; Gorchakov, Victor; Martjyanov, Stanislav

    2016-04-01

    This study is aimed to assess the impact of sea ice on the primary production of phytoplankton (PPP) and air-sea CO2 flux in the Barents Sea. To get the estimations, we apply a three-dimensional eco-hydrodynamic model based on the Princeton Ocean Model which includes: 1) a module of sea ice with 7 categories, and 2) the 11-component module of marine pelagic ecosystem developed in the St. Petersburg Branch, Institute of Oceanology. The model is driven by atmospheric forcing, prescribed from the reanalysis NCEP / NCAR, and conditions on the open sea boundary, prescribed from the regional model of the atmosphere-ocean-sea ice-ocean biogeochemistry, developed at Max Planck Institute for Meteorology, Hamburg. Comparison of the model results for the period 1998-2007 with satellite data showed that the model reproduces the main features of the evolution of the sea surface temperature, seasonal changes in the ice extent, surface chlorophyll "a" concentration and PPP in the Barents Sea. Model estimates of the annual PPP for whole sea, APPmod, appeared in 1.5-2.3 times more than similar estimates, APPdata, from satellite data. The main reasons for this discrepancy are: 1) APPdata refers to the open water, while APPmod, to the whole sea area (under the pack ice and marginal ice zone (MIZ) was produced 16 - 38% of PPP); and 2) values of APPdata are underestimated because of the subsurface chlorophyll maximum. During the period 1998-2007, the modelled maximal (in the seasonal cycle) sea ice area has decreased by 15%. This reduction was accompanied by an increase in annual PPP of the sea at 54 and 63%, based, respectively, on satellite data and the model for the open water. According to model calculations for the whole sea area, the increase is only 19%. Using a simple 7-component model of oceanic carbon cycle incorporated into the above hydrodynamic model, the CO2 exchange between the atmosphere and sea has been estimated in different conditions. In the absence of biological

  12. Resilience of a High Latitude Red Sea Frining Corals Exposed to Extreme Temperatures

    NASA Astrophysics Data System (ADS)

    Moustafa, M.; Moustafa, M. S.; Moustafa, S.; Moustafa, Z. D.

    2013-05-01

    Since 2004, multi-year study set out to establish linkages between fringing coral reefs in the northern Gulf of Suez, Red Sea, and local weather. Insight into local meteorological processes may provide a better understanding of the direct influence weather has on a fringing coral reef. To establish trends, seawater temperature and meteorological record were collected at a small fringing coral reef (Zaki's Reef), located near Ein Sokhna, Egypt (29.5oN & 32.4oE). Monitoring air and water temperature provides evidence of seasonality and interannual variability and may reveal correlations between reef health and climate conditions in this region. Prior to this study, there were no known long-term studies investigating coral reefs in this region. Approximately 35 coral taxa are known to survive the extreme temperature and salinity regime found here, yet only six corals compose 94% of coral cover on Zaki's Reef. Dominant corals include: Acropora humilis, A. microclados, A. hemprichii, Litophyton arboretum, Stylophora pistillata, Porites columna, and P. plantulata. Seawater temperatures were collected at 30 minutes intervals at 5 locations. Seawater temperature data indicate that corals experience 4-6.5oC daily temperature variations and seasonal variations that exceed 29oC. Air temperatures were collected just landward of the reef were compared to Hurghada and Ismailia 400 and 200 km south and north of the study site, respectively. Time series analysis results indicate that air temperature dominant frequencies are half-daily, daily, and yearly cycles, while water temperatures show yearly cycles. A comparison of air temperature with neighboring locations indicates that air temperatures at Ein Sokhna ranged between near 0o C to an excess of 55o C, yet, daily means for Ein Sokhna and Hurghada were very similar (24.2o C and. 25.2o C, respectively). Maximum daily air temperatures at the study site exceeded maximum air temperature at Hurghada (400 km south) by almost 7o C

  13. Simulation and Prediction of North Pacific Sea Surface Temperature

    NASA Astrophysics Data System (ADS)

    Lienert, Fabian

    The first part of this thesis is an assessment of the ability of global climate models to reproduce observed features of the leading Empirical Orthogonal Function (EOF) mode of North Pacific sea surface temperature (SST) anomalies known as the Pacific Decadal Oscillation (PDO). My results are that 1) the models as group produce a realistic pattern of the PDO. The simulated variance of the PDO index is overestimated by roughly 30%. 2) The tropical influence on North Pacific SSTs is biased systematically in these models. The simulated response to El Nino-Southern Oscillation (ENSO) forcing is delayed compared to the observed response. This tendency is consistent with model biases toward deeper oceanic mixed layers in winter and spring and weaker air-sea feedbacks in the winter half-year. Model biases in mixed layer depths and air-sea feedbacks are also associated with a model mean ENSO-related signal in the North Pacific whose amplitude is overestimated by roughly 30%. Finally, model power spectra of the PDO signal and its ENSO-forced component are "redder" than observed due to errors originating in the tropics and extratropics. 3) The models are quite successful at capturing the influence of both the tropical Pacific related and the extratropical part of the PDO on North American surface temperature. 4) The models capture some of the influence of the PDO on North American precipitation mainly due to its tropical Pacific related part. In the second part of this thesis, I investigate the ability of one such coupled ocean-atmosphere climate model, carefully initialized with observations, to dynamically predict the future evolution of the PDO on seasonal to decadal time scales. I find that 1) CHFP2 is successful at predicting the PDO at the seasonal time scale measured by mean-square skill score and correlation skill. Weather "noise" unpredictable at the seasonal time scale generated by substantial North Pacific storm track activity that coincides with a shallow oceanic

  14. Micrometeorological survey of air-sea ice CO2 fluxes in arctic coastal waters

    NASA Astrophysics Data System (ADS)

    Heinesch, Bernard; Tison, Jean-Louis; Carnat, Gauthier; Heicken, Hajo; Geilfus, Nicolas-Xavier; Goosens, Thomas; Papakyriakou, Tim; Yernaux, Michel; Delille, Bruno

    2010-05-01

    We carried out a 6 month study that aimed to robustly track CO2 exchange between land-fast sea-ice and the atmosphere during the winter and spring season. A meteorological mast equipped for eddy-covariance measurements was installed on land-fast sea-ice near Barrow (Alaska), 1 km off the coast, from the end of January 2009 to the beginning of June 2009, before ice break-up. These data were supported by continuous measurements of solar radiation, snow depth, ice thickness and temperature profile in the ice. Biogeochemical data necessary for the understanding of the CO2 dynamics in sea-ice were obtained through discrete ice coring. Two regimes were detected for the CO2 exchanges linked with the status of the sea-ice: a winter regime and a spring summer regime. From 27 of March onwards brine volume at the sea ice-snow interface was above the threshold of permeability for liquid according to Golden et al (1998). During this period, we observed some conspicuous CO2 fluxes events tightly linked to wind speed. The flux was directed from the sea-ice to the atmosphere and reached up to 0.6 umol m-2 s-1 (51.8 mmol m-2 d-1). This flux to the atmosphere is expected as sea-ice at the air interface is permeable during a large part of the period and brines are oversaturated compared to the atmosphere. CO2 may accumulate in the snow layer which thus acts as a buffer that is flushed under occurrence of high wind speeds and associated pressure pumping. During the spring-summer period i.e. from 27 of April onwards, we observed a marked increase in sea ice temperature. Temperature profiles suggest that convective events occurred within the ice cover between April 27 and May 05. Within these convective events, two regimes were observed. First, for a period of 5 days, pCO2 was still above the threshold of saturation and CO2 fluxes were still mainly positive but lower than in the winter period, ranging from 0.1 to 0.2 umol m-2 s-1. This flux was only moderately controlled by windspeed

  15. Sea-level and deep-sea-temperature variability over the past 5.3 million years.

    PubMed

    Rohling, E J; Foster, G L; Grant, K M; Marino, G; Roberts, A P; Tamisiea, M E; Williams, F

    2014-04-24

    Ice volume (and hence sea level) and deep-sea temperature are key measures of global climate change. Sea level has been documented using several independent methods over the past 0.5 million years (Myr). Older periods, however, lack such independent validation; all existing records are related to deep-sea oxygen isotope (δ(18)O) data that are influenced by processes unrelated to sea level. For deep-sea temperature, only one continuous high-resolution (Mg/Ca-based) record exists, with related sea-level estimates, spanning the past 1.5 Myr. Here we present a novel sea-level reconstruction, with associated estimates of deep-sea temperature, which independently validates the previous 0-1.5 Myr reconstruction and extends it back to 5.3 Myr ago. We find that deep-sea temperature and sea level generally decreased through time, but distinctly out of synchrony, which is remarkable given the importance of ice-albedo feedbacks on the radiative forcing of climate. In particular, we observe a large temporal offset during the onset of Plio-Pleistocene ice ages, between a marked cooling step at 2.73 Myr ago and the first major glaciation at 2.15 Myr ago. Last, we tentatively infer that ice sheets may have grown largest during glacials with more modest reductions in deep-sea temperature. PMID:24739960

  16. High temperatures in the Barents Sea in 2013

    NASA Astrophysics Data System (ADS)

    Chepurin, Gennady; Carton, James

    2014-05-01

    During this past summer SST in the Barents Sea of the Eurasian Arctic reached its highest value since satellite infrared measurements began in 1981, with multi-satellite Pathfinder anomalies exceeding 4°C (3.5°C if a temporal warming trend is removed). The anomalies which began to develop in the Barents Sea in May and gradually expanded into the Kara Sea during the summer, largely subsided by November. This warming of the Eurasian side of the Arctic is in striking contrast to the pattern of warming in 2007 when the Pacific side of the Arctic was warm and the Barents Sea was cool. The shift of SST anomalies across the Arctic has potentially important consequences for meteorological conditions in this region. Indeed atmospheric conditions this past summer were also anomalous, with unusually clear skies and August surface winds shifting from the expected northerly direction to westerly. The causes of the summer 2013 anomalous warming are complex. In the seasonal heat budget of the Barents Sea convergence of heat is important due to the eastward advection and surfacing of warm, salty Atlantic Water, and is balanced by surface cooling in winter. In spring of this year the Barents Sea ice retreat came early in the north and east, one impact of which was a greater opportunity for high solar absorption into the surface ocean (ice-albedo feedback) and high air humidity. To quantify the net surface heating contribution we present results from the NCEP and ERA Interim atmospheric reanalyses, and scatterometer winds, while to estimate the potential ocean contribution we examine ocean heat convergence in ocean models. The current results suggest that the anomalous conditions were forced by both anomalous surface fluxes, particularly net solar radiation, and ocean heat convergence due to anomalous transport of Atlantic Water.

  17. The OceanFlux Greenhouse Gases methodology for deriving a sea surface climatology of CO2 fugacity in support of air-sea gas flux studies

    NASA Astrophysics Data System (ADS)

    Goddijn-Murphy, L. M.; Woolf, D. K.; Land, P. E.; Shutler, J. D.; Donlon, C.

    2015-07-01

    Climatologies, or long-term averages, of essential climate variables are useful for evaluating models and providing a baseline for studying anomalies. The Surface Ocean CO2 Atlas (SOCAT) has made millions of global underway sea surface measurements of CO2 publicly available, all in a uniform format and presented as fugacity, fCO2. As fCO2 is highly sensitive to temperature, the measurements are only valid for the instantaneous sea surface temperature (SST) that is measured concurrently with the in-water CO2 measurement. To create a climatology of fCO2 data suitable for calculating air-sea CO2 fluxes, it is therefore desirable to calculate fCO2 valid for a more consistent and averaged SST. This paper presents the OceanFlux Greenhouse Gases methodology for creating such a climatology. We recomputed SOCAT's fCO2 values for their respective measurement month and year using monthly composite SST data on a 1° × 1° grid from satellite Earth observation and then extrapolated the resulting fCO2 values to reference year 2010. The data were then spatially interpolated onto a 1° × 1° grid of the global oceans to produce 12 monthly fCO2 distributions for 2010, including the prediction errors of fCO2 produced by the spatial interpolation technique. The partial pressure of CO2 (pCO2) is also provided for those who prefer to use pCO2. The CO2 concentration difference between ocean and atmosphere is the thermodynamic driving force of the air-sea CO2 flux, and hence the presented fCO2 distributions can be used in air-sea gas flux calculations together with climatologies of other climate variables.

  18. Flight crew fatigue III: North Sea helicopter air transport operations.

    PubMed

    Gander, P H; Barnes, R M; Gregory, K B; Graeber, R C; Connell, L J; Rosekind, M R

    1998-09-01

    We studied 32 helicopter pilots before, during, and after 4-5 d trips from Aberdeen, Scotland, to service North Sea oil rigs. On duty days, subjects awoke 1.5 h earlier than pretrip or posttrip, after having slept nearly an hour less. Subjective fatigue was greater posttrip than pretrip. By the end of trip days, fatigue was greater and mood more negative than by the end of pretrip days. During trips, daily caffeine consumption increased 42%, reports of headache doubled, reports of back pain increased 12-fold, and reports of burning eyes quadrupled. In the cockpits studied, thermal discomfort and high vibration levels were common. Subjective workload during preflight, taxi, climb, and cruise was related to the crewmembers' ratings of the quality of the aircraft systems. During descent and approach, workload was affected by weather at the landing site. During landing, it was influenced by the quality of the landing site and air traffic control. Beginning duty later, and greater attention to aircraft comfort and maintenance, should reduce fatigue in these operations. PMID:9749937

  19. Improvement of the GEOS-5 AGCM upon Updating the Air-Sea Roughness Parameterization

    NASA Technical Reports Server (NTRS)

    Garfinkel, C. I.; Molod, A.; Oman, L. D.; Song, I.-S.

    2011-01-01

    The impact of an air-sea roughness parameterization over the ocean that more closely matches recent observations of air-sea exchange is examined in the NASA Goddard Earth Observing System, version 5 (GEOS-5) atmospheric general circulation model. Surface wind biases in the GEOS-5 AGCM are decreased by up to 1.2m/s. The new parameterization also has implications aloft as improvements extend into the stratosphere. Many other GCMs (both for operational weather forecasting and climate) use a similar class of parameterization for their air-sea roughness scheme. We therefore expect that results from GEOS-5 are relevant to other models as well.

  20. On model differences and skill in predicting sea surface temperature in the Nordic and Barents Seas

    NASA Astrophysics Data System (ADS)

    Langehaug, H. R.; Matei, D.; Eldevik, T.; Lohmann, K.; Gao, Y.

    2016-04-01

    The Nordic Seas and the Barents Sea is the Atlantic Ocean's gateway to the Arctic Ocean, and the Gulf Stream's northern extension brings large amounts of heat into this region and modulates climate in northwestern Europe. We have investigated the predictive skill of initialized hindcast simulations performed with three state-of-the-art climate prediction models within the CMIP5-framework, focusing on sea surface temperature (SST) in the Nordic Seas and Barents Sea, but also on sea ice extent, and the subpolar North Atlantic upstream. The hindcasts are compared with observation-based SST for the period 1961-2010. All models have significant predictive skill in specific regions at certain lead times. However, among the three models there is little consistency concerning which regions that display predictive skill and at what lead times. For instance, in the eastern Nordic Seas, only one model has significant skill in predicting observed SST variability at longer lead times (7-10 years). This region is of particular promise in terms of predictability, as observed thermohaline anomalies progress from the subpolar North Atlantic to the Fram Strait within the time frame of a couple of years. In the same model, predictive skill appears to move northward along a similar route as forecast time progresses. We attribute this to the northward advection of SST anomalies, contributing to skill at longer lead times in the eastern Nordic Seas. The skill at these lead times in particular beats that of persistence forecast, again indicating the potential role of ocean circulation as a source for skill. Furthermore, we discuss possible explanations for the difference in skill among models, such as different model resolutions, initialization techniques, and model climatologies and variance.

  1. Spatial and temporal variability of sea-surface temperature fronts in the coastal Beaufort Sea

    NASA Astrophysics Data System (ADS)

    Mustapha, Sélima Ben; Larouche, Pierre; Dubois, Jean-Marie

    2016-08-01

    An analysis of 11 years of sea surface temperatures images allowed the determination of the frontal occurrence probability in the southeastern Beaufort Sea using the single-image edge detection method. Results showed that, as the season progresses, fronts become more detectable due to solar heating of the surface layer. Some recurrent features can be identified in the summer time frontal climatology such as the Mackenzie River plume front, the Cape Bathurst front, the Mackenzie Trough front and the Amundsen Gulf front. These areas may be playing an important role in the biological processes acting as drivers to local enhanced biological productivity.

  2. Evaluation of the swell effect on the air-sea gas transfer in the coastal zone

    NASA Astrophysics Data System (ADS)

    Gutiérrez-Loza, Lucía; Ocampo-Torres, Francisco J.

    2016-04-01

    Air-sea gas transfer processes are one of the most important factors regarding global climate and long-term global climate changes. Despite its importance, there is still a huge uncertainty on how to better parametrize these processes in order to include them on the global climate models. This uncertainty exposes the need to increase our knowledge on gas transfer controlling mechanisms. In the coastal regions, breaking waves become a key factor to take into account when estimating gas fluxes, however, there is still a lack of information and the influence of the ocean surface waves on the air-sea interaction and gas flux behavior must be validated. In this study, as part of the "Sea Surface Roughness as Air-Sea Interaction Control" project, we evaluate the effect of the ocean surface waves on the gas exchange in the coastal zone. Direct estimates of the flux of CO2 (FCO2) and water vapor (FH2O) through eddy covariance, were carried out from May 2014 to April 2015 in a coastal station located at the Northwest of Todos Santos Bay, Baja California, México. For the same period, ocean surface waves are recorded using an Acoustic Doppler Current Profiler (Workhorse Sentinel, Teledyne RD Instruments) with a sampling rate of 2 Hz and located at 10 m depth about 350 m away from the tower. We found the study area to be a weak sink of CO2 under moderate wind and wave conditions with a mean flux of -1.32 μmol/m2s. The correlation between the wind speed and FCO2 was found to be weak, suggesting that other physical processes besides wind may be important factors for the gas exchange modulation at coastal waters. The results of the quantile regression analysis computed between FCO2 and (1) wind speed, (2) significant wave height, (3) wave steepness and (4) water temperature, show that the significant wave height is the most correlated parameter with FCO2; Nevertheless, the behavior of their relation varies along the probability distribution of FCO2, with the linear regression

  3. The Aeroclipper: A new instrument for quasi-Lagrangian measurements at the air-sea interface

    NASA Astrophysics Data System (ADS)

    Duvel, J. P.; Reverdin, G.; Pichon, T.; Vargas, A.

    The Aeroclipper is a new balloon developed by CNES. The Aeroclipper is a balloon equipped with a cable extended by a guide-rope in contact with the surface of the ocean. The balloon is vertically stabilised at a given height (currently 40 to 60m above the sea surface) and move on quasi-Lagrangian trajectories depending on the surface wind. LMD (Laboratoire de Méteorologie Dynamique), LodyC (Laboratoire d'océanographie physique et de Climatologie) and ENSTA (Ecole Nationale Supérieure de Techniques Avancées) developed an instrumentation adapted to this new measurement system. This instrumentation is distributed on one atmospheric gondola and one oceanic gondola. The aim is to measure surface physical parameters (Air and sea surface temperatures, sea surface salinity, wind, pressure and humidity) and to derive turbulent fluxes of moisture, heat and momentum. The Aeroclippers will give legs of the different parameters at a relatively high spatial resolution and thus information on the perturbation of these parameters at mesoscale. A first test of the full system will be performed from Banyuls (France) during spring 2004. The first scientific use of the Aeroclipper is planned in February 2005 in the Indian Ocean South of the Equator in link with the pilot phase of the Vasco (Variability of the Atmosphere at the intra-Seasonal time scale and Coupling with the Ocean) experiment.

  4. Air pollutant transport in a coastal environment. Part 1: Two-dimensional simulations of sea-breeze and mountain effects

    NASA Technical Reports Server (NTRS)

    Lu, Rong; Turco, Richard P.

    1994-01-01

    Over the southern California coastal region, observations of the vertical distributions of pollutants show that maximum concentrations can occur within temperature inversion layers well above the surface. A mesoscale model is used to study the dynamical phenomena that cause such layers, including sea breezes and mountain flows, and to study the characteristics of air pollutant transport in a coastal environment capped by a temperature inversion. The mathematical and physical structure of the model is described. Two-dimensional simulations corresponding to four configurations of coastal plains and mountains are discussed. The simulations reveal that pollutant transport over a coastal plain is strongly influenced by the topographic configuration, including the height of coastal mountains and their distance from the coastline. Sea breezes induced by land-sea thermal contrasts, as well as upslope winds induced along mountain flanks, both create vertical transport that can lead to the formation of elevated pollution layers. The sea-breeze circulation generates pollution layers by undercutting the mixed layer and lofting pollutants into the stable layer. Heating of mountain slopes acts to vent pollutants above the mountain ridge during the day; during the evening, pollutants can be injected directly into the inversion layer from the decaying upslope flows. In a land-sea configuration with mountains close to the coastline, the sea breeze and heated-mountain flow are strongly coupled. In the afternoon, this interaction can produce upslope flow from which polluted air is detrained into the inversion layer as a return circulation. When the mountains lie farther inland, however, pollutants may be trapped aloft when the mixed layer stabilizes in the late afternoon. As the nocturnal boundary layer forms over the coast in the evening, polluted mixed-layer air is effectively left behind in the inversion layer. In the Los Angeles Basin, the formation mechanism for elevated

  5. Sea surface temperature contributes to marine crocodylomorph evolution.

    PubMed

    Martin, Jeremy E; Amiot, Romain; Lécuyer, Christophe; Benton, Michael J

    2014-01-01

    During the Mesozoic and Cenozoic, four distinct crocodylomorph lineages colonized the marine environment. They were conspicuously absent from high latitudes, which in the Mesozoic were occupied by warm-blooded ichthyosaurs and plesiosaurs. Despite a relatively well-constrained stratigraphic distribution, the varying diversities of marine crocodylomorphs are poorly understood, because their extinctions neither coincided with any major biological crises nor with the advent of potential competitors. Here we test the potential link between their evolutionary history in terms of taxic diversity and two abiotic factors, sea level variations and sea surface temperatures (SST). Excluding Metriorhynchoidea, which may have had a peculiar ecology, significant correlations obtained between generic diversity and estimated Tethyan SST suggest that water temperature was a driver of marine crocodylomorph diversity. Being most probably ectothermic reptiles, these lineages colonized the marine realm and diversified during warm periods, then declined or became extinct during cold intervals. PMID:25130564

  6. Satellite-Derived Sea Surface Temperature: Workshop-2

    NASA Technical Reports Server (NTRS)

    Njoku, E. G.

    1984-01-01

    Global accuracies and error characteristics of presently orbiting satellite sensors are examined. The workshops are intended to lead to a better understanding of present capabilities for sea surface temperature measurement and to improve measurement concepts for the future. Data from the Advanced Very High Resolution Radiometer AVHRR and Scanning Multichannel Microwave Radiometer is emphasized. Some data from the High Resolution Infrared Sounder HIRS and AVHRR are also examined. Comparisons of satellite data with ship and eXpendable BathyThermograph XBT measurement show standard deviations in the range 0.5 to 1.3 C with biases of less than 0.4 C, depending on the sensor, ocean region, and spatial/temporal averaging. The Sea Surface Temperature SST anomaly maps show good agreement in some cases, but a number of sensor related problems are identified.

  7. Satellite-Derived Sea Surface Temperature: Workshop 1

    NASA Technical Reports Server (NTRS)

    Njoku, E. G.

    1983-01-01

    Satellite measurements of sea surface temperature are now possible using a variety of sensors. The present accuracies of these methods are in the range of 0.5 to 2.0 C. This makes them potentially useful for synoptic studies of ocean currents and for global monitoring of climatological anomalies. To improve confidence in the satellite data, objective evaluations of sensor accuracies are necessary, and the conditions under which these accuracies degrade need to be understood. The Scanning Multichannel Microwave Radiometer (SMMR) on the Nimbus-7 satellite was studied. Sea surface temperatures, derived from November 1979 SMMR data, were compared globally against ship measurements and climatology, using facilities of the JPL Pilot Ocean Data System. Methods for improved data analysis and plans for additional workshops to incorporate data from other sensors were discussed.

  8. Hurricane Isabel, AIRS Infrared and SeaWinds Scatterometer Data Combined

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 1Figure 2

    These two images show Hurricane Isabel as viewed by AIRS and each of the two SeaWinds scatterometers on the ADEOS-2 and QuikScat satellites, all JPL-managed experiments. AIRS data are used to create global three-dimensional maps of temperature, humidity and clouds, while scatterometers measure surface wind speed and direction.

    Figure 1 shows Isabel on September 13, 2003, when it was a Category 5 storm threatening the Caribbean and southern United States. At the time Isabel was the strongest Atlantic storm since hurricane Mitch killed thousands in central America in 1997. The red vectors in the image show Isabel's surface winds as measured by SeaWinds on ADEOS-2, and the background colors show the temperature of clouds and surface, as viewed in the infrared by AIRS. The hurricane's powerful swirling winds are apparent. These winds circle the hurricane's eye, seen as the red dot near the middle top of the image. Light blue areas shows adjacent cold clouds tops associated with strong thunderstorms embedded within the storm.

    Figure 2 shows Isabel as it approached landfall on the outer banks of North Carolina on September 18. The hurricane weakened in the five days since the earlier image was observed, as indicated by a less clearly defined eye. Nevertheless, it was still a powerful storm. The winds blowing onshore north of the eye knocked over trees, blew roofs off buildings, and drove large waves that breached the coastal barrier islands in many places. Water, transportation and power are still not fully restored to many of the areas in the image. The winds apparently blowing away from the eye of the storm are an artifact of one of the hurricane's other destructive phenomena: rain. The darkest blue clouds observed by AIRS show the most intense thunderstorms, and hence the heaviest rains. Hard rain fools the the SeaWinds on Quik

  9. Variability of sea surface temperatures and sea ice in Baffin Bay during the last two millennia

    NASA Astrophysics Data System (ADS)

    Oksman, Mimmi; Miettinen, Arto; Kucera, Michal

    2013-04-01

    The Arctic region has undergone very rapid changes in the past 50 years. Climate models predict accelerating rates of change in the Arctic and long-term perspectives on natural climate variability are therefore needed to understand these changes and their further effects. We used marine fossil diatom assemblages from Baffin Bay to investigate August sea surface temperatures (aSSTs) and sea ice variability during the last two millennia. The Baffin Bay area is sensitive to changes in the climate system due to its location, where it is influenced by Atlantic and Arctic water masses. The top most 77 cm of a 600 cm long marine sediment core (GeoTü SL-170) was used for a high resolution study of quantitative SST and sea ice reconstructions based on fossil marine planktonic diatoms. A calibration dataset consisting of 155 surface samples from the North Atlantic and a new set of 24 surface samples from Baffin Bay with 52 diatom species was utilized to convert diatom counts to aSSTs using the weighted averaging partial least squares (WA-PLS) transfer function method. The sea ice reconstruction was based on a qualitative method for specific diatom assemblages and quantitative sea ice reconstructions for the May sea ice cover based on the Maximum likelihood (ML) transfer function method. The age model for the core is based on the 14C method. Our data shows a slight warming trend of the surface waters in Baffin Bay for the last ca. 2 kyr. The most dominating diatom species is Thalassiosira gravida spores, which represents typical "Baffin Current assemblage". The highest aSSTs occurred during the Medieval Warm Period (MWP), presumably due to the increased advection of warm Atlantic water from the West Greenland Current into Baffin Bay. After the MWP, the sediment was poor in diatoms during the Little Ice Age (LIA) suggesting that the study area was covered by sea ice also in the summertime.

  10. Correlation and coherence analysis between sea surface temperature and altimetric sea level anomaly data

    NASA Astrophysics Data System (ADS)

    Zbylut-Górska, Maria; Kosek, Wiesław; Wnęk, Agnieszka; Młocek, Wojciech; Rutkowska, Agnieszka; Popiński, Waldemar; Niedzielski, Tomasz

    2016-04-01

    One of the main causes of the sea level variations is the steric effect caused by changes of local sea surface temperature (SST). To show how the altimetric Sea Level Anomaly (SLA) data are related to the SST data, correlation coefficients between them as a function of geographic location were computed. The analysis showed a high positive correlation (about 0.7), especially in the Northern and South-Eastern parts of the Pacific Ocean and a large part of the Atlantic Ocean. There is a negative correlation of about 0.5 in the South-East part of Indian Ocean, on the Arafura Sea and the Red Sea. In addition the time-frequency coherence and semblance functions between the SLA and SST data were calculated using Fourier transform band pass filter. The maps of such coherence and semblance functions in frequency bands corresponding to the annual oscillation and its integer multiplicities were computed. The most imporntat contribution to the correlation coefficient values has the annual oscillation in the SST and SLA data.

  11. Sea surface temperature and salinity seasonal changes in the western Solomon and Bismarck Seas

    NASA Astrophysics Data System (ADS)

    Delcroix, Thierry; Radenac, Marie-Hélène; Cravatte, Sophie; Alory, Gaël.; Gourdeau, Lionel; Léger, Fabien; Singh, Awnesh; Varillon, David

    2014-04-01

    We analyze mean and seasonal change of Sea Surface Temperature (SST) and Salinity (SSS) in the Solomon and Bismarck Seas, using 1977-2009 in situ data collected from Voluntary Observing Ships. Covariability of these two variables with surface wind, altimeter-derived and model-derived horizontal currents, precipitation, and Sepik River discharge are examined. SST and SSS show large annual oscillations in the Solomon Sea, with the coldest and saltiest waters occurring in July/August mainly due to horizontal advection. In contrast, they show large semiannual oscillations in the Bismarck Sea. There, the coldest and saltiest waters happen in January/February, when the northwest monsoon winds drive coastal upwelling, and in July/August, when the New Guinea Coastal Current advects cold and high-salinity waters from the Solomon Sea through Vitiaz Strait. The low SSS values observed in April/May, stuck between the January/February and July/August SSS maxima, are further enhanced by the Sepik River discharge annual maximum. A high-resolution model strengthens the conclusions we derive from observations. The impacts of ENSO on SST and SSS are also discussed with, for instance, saltier-than-average and fresher-than-average waters during the 2002-2003 El Niño and 2007-2008 La Niña, respectively.

  12. Estimation of Surface Air Temperature from MODIS 1km Resolution Land Surface Temperature Over Northern China

    NASA Technical Reports Server (NTRS)

    Shen, Suhung; Leptoukh, Gregory G.; Gerasimov, Irina

    2010-01-01

    Surface air temperature is a critical variable to describe the energy and water cycle of the Earth-atmosphere system and is a key input element for hydrology and land surface models. It is a very important variable in agricultural applications and climate change studies. This is a preliminary study to examine statistical relationships between ground meteorological station measured surface daily maximum/minimum air temperature and satellite remotely sensed land surface temperature from MODIS over the dry and semiarid regions of northern China. Studies were conducted for both MODIS-Terra and MODIS-Aqua by using year 2009 data. Results indicate that the relationships between surface air temperature and remotely sensed land surface temperature are statistically significant. The relationships between the maximum air temperature and daytime land surface temperature depends significantly on land surface types and vegetation index, but the minimum air temperature and nighttime land surface temperature has little dependence on the surface conditions. Based on linear regression relationship between surface air temperature and MODIS land surface temperature, surface maximum and minimum air temperatures are estimated from 1km MODIS land surface temperature under clear sky conditions. The statistical errors (sigma) of the estimated daily maximum (minimum) air temperature is about 3.8 C(3.7 C).

  13. Imaging air volume fraction in sea ice using non-destructive X-ray tomography

    NASA Astrophysics Data System (ADS)

    Crabeck, Odile; Galley, Ryan; Delille, Bruno; Else, Brent; Geilfus, Nicolas-Xavier; Lemes, Marcos; Des Roches, Mathieu; Francus, Pierre; Tison, Jean-Louis; Rysgaard, Søren

    2016-05-01

    Although the presence of a gas phase in sea ice creates the potential for gas exchange with the atmosphere, the distribution of gas bubbles and transport of gases within the sea ice are still poorly understood. Currently no straightforward technique exists to measure the vertical distribution of air volume fraction in sea ice. Here, we present a new fast and non-destructive X-ray computed tomography technique to quantify the air volume fraction and produce separate images of air volume inclusions in sea ice. The technique was performed on relatively thin (4-22 cm) sea ice collected from an experimental ice tank. While most of the internal layers showed air volume fractions < 2 %, the ice-air interface (top 2 cm) systematically showed values up to 5 %. We suggest that the air volume fraction is a function of both the bulk ice gas saturation factor and the brine volume fraction. We differentiate micro bubbles (Ø < 1 mm), large bubbles (1 mm < Ø < 5 mm) and macro bubbles (Ø > 5 mm). While micro bubbles were the most abundant type of gas bubbles, most of the air porosity observed resulted from the presence of large and macro bubbles. The ice texture (granular and columnar) as well as the permeability state of ice are important factors controlling the air volume fraction. The technique developed is suited for studies related to gas transport and bubble migration.

  14. Multiyear predictability of Northern Hemisphere surface air temperature in the Kiel Climate Model

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Latif, M.; Park, W.

    2015-10-01

    The multiyear predictability of Northern Hemisphere surface air temperature (SAT) is examined in a multi-millennial control integration of the Kiel Climate Model, a coupled ocean-atmosphere-sea ice general circulation model. A statistical method maximizing average predictability time (APT) is used to identify the most predictable SAT patterns in the model. The two leading APT modes are much localized and the physics are discussed that give rise to the enhanced predictability of SAT in these limited regions. Multiyear SAT predictability exists near the sea ice margin in the North Atlantic and mid-latitude North Pacific sector. Enhanced predictability in the North Atlantic is linked to the Atlantic Multidecadal Oscillation and to the sea ice changes. In the North Pacific, the most predictable SAT pattern is characterized by a zonal band in the western and central mid-latitude Pacific. This pattern is linked to the Pacific Decadal Oscillation, which drives sea surface temperature anomalies. The temperature anomalies subduct into deeper ocean layers and re-emerge at the sea surface during the following winters, providing multiyear memory. Results obtained from the Coupled Model Intercomparison Project Phase 5 ensemble yield similar APT modes. Overall, the results stress the importance of ocean dynamics in enhancing predictability in the atmosphere.

  15. Multiyear predictability of Northern Hemisphere surface air temperature in the Kiel Climate Model

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Latif, M.; Park, W.

    2016-08-01

    The multiyear predictability of Northern Hemisphere surface air temperature (SAT) is examined in a multi-millennial control integration of the Kiel Climate Model, a coupled ocean-atmosphere-sea ice general circulation model. A statistical method maximizing average predictability time (APT) is used to identify the most predictable SAT patterns in the model. The two leading APT modes are much localized and the physics are discussed that give rise to the enhanced predictability of SAT in these limited regions. Multiyear SAT predictability exists near the sea ice margin in the North Atlantic and mid-latitude North Pacific sector. Enhanced predictability in the North Atlantic is linked to the Atlantic Multidecadal Oscillation and to the sea ice changes. In the North Pacific, the most predictable SAT pattern is characterized by a zonal band in the western and central mid-latitude Pacific. This pattern is linked to the Pacific Decadal Oscillation, which drives sea surface temperature anomalies. The temperature anomalies subduct into deeper ocean layers and re-emerge at the sea surface during the following winters, providing multiyear memory. Results obtained from the Coupled Model Intercomparison Project Phase 5 ensemble yield similar APT modes. Overall, the results stress the importance of ocean dynamics in enhancing predictability in the atmosphere.

  16. Precipitation and temperature changes in the major Chinese river basins during 1957-2013 and links to sea surface temperature

    NASA Astrophysics Data System (ADS)

    Tian, Qing; Prange, Matthias; Merkel, Ute

    2016-05-01

    The variation characteristics of precipitation and temperature in the three major Chinese river basins (Yellow River, Yangtze River and Pearl River) in the period of 1957-2013 were analyzed on an annual and seasonal basis, as well as their links to sea surface temperature (SST) variations in the tropical Pacific and Indian Ocean on both interannual and decadal time scales. Annual mean temperature of the three river basins increased significantly overall since 1957, with an average warming rate of about 0.19 °C/10a, but the warming was characterized by a staircase form with steps around 1987 and 1998. The significant increase of annual mean temperature could mostly be attributed to the remarkable warming trend in spring, autumn and winter. Warming rates in the northern basins were generally much higher than in the southern basins. However, both the annual precipitation and seasonal mean precipitation of the three river basins showed little change in the study area average, but distinct interannual variations since 1957 and clear regional differences. An overall warming-wetting tendency was found in the northwestern and southeastern river basins in 1957-2013, while the central regions tended to become warmer and drier. Results from a Maximum Covariance Analysis (MCA) showed that the interannual variations of seasonal mean precipitation and surface air temperature over the three river basins were both associated with the El Niño-Southern Oscillation (ENSO) since 1957. ENSO SST patterns affected precipitation and surface air temperature variability throughout the year, but with very different response patterns in the different seasons. For instance, temperature in most of the river basins was positively correlated with central-eastern equatorial Pacific SST in winter and spring, but negatively correlated in summer and autumn. On the decadal time scale, the seasonal mean precipitation and surface air temperature variations were strongly associated with the Pacific

  17. Air-sea interaction in the tropical Pacific Ocean

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  18. Mechanisms controlling the SST air-sea heat flux feedback and its dependence on spatial scale

    NASA Astrophysics Data System (ADS)

    Hausmann, Ute; Czaja, Arnaud; Marshall, John

    2016-05-01

    The turbulent air-sea heat flux feedback (α , in {W m}^{-2}{ K}^{-1} ) is a major contributor to setting the damping timescale of sea surface temperature (SST) anomalies. In this study we compare the spatial distribution and magnitude of α in the North Atlantic and the Southern Ocean, as estimated from the ERA-Interim reanalysis dataset. The comparison is rationalized in terms of an upper bound on the heat flux feedback, associated with "fast" atmospheric export of temperature and moisture anomalies away from the marine boundary layer, and a lower bound associated with "slow" export. It is found that regions of cold surface waters (≤ 10° C) are best described as approaching the slow export limit. This conclusion is not only valid at the synoptic scale resolved by the reanalysis data, but also on basin scales. In particular, it applies to the heat flux feedback acting as circumpolar SST anomaly scales are approached in the Southern Ocean, with feedbacks of ≤ 10 {W m}^{-2}{ K}^{-1} . In contrast, the magnitude of the heat flux feedback is close to that expected from the fast export limit over the Gulf Stream and its recirculation with values on the order of ≈40 {W m}^{-2}{ K}^{-1} . Further analysis suggests that this high value reflects a compensation between a moderate thermodynamic adjustment of the boundary layer, which tends to weaken the heat flux feedback, and an enhancement of the surface winds over warm SST anomalies, which tend to enhance the feedback.

  19. Sea-surface temperature and salinity mapping from remote microwave radiometric measurements of brightness temperature

    NASA Technical Reports Server (NTRS)

    Hans-Juergen, C. B.; Kendall, B. M.; Fedors, J. C.

    1977-01-01

    A technique to measure remotely sea surface temperature and salinity was demonstrated with a dual frequency microwave radiometer system. Accuracies in temperature of 1 C and in salinity of part thousand for salinity greater than 5 parts per thousand were attained after correcting for the influence of extraterrestrial background radiation, atmospheric radiation and attenuation, sea-surface roughness, and antenna beamwidth. The radiometers, operating at 1.43 and 2.65 GHz, comprise a third-generation system using null balancing and feedback noise injection. Flight measurements from an aircraft at an altitude of 1.4 km over the lower Chesapeake Bay and coastal areas of the Atlantic Ocean resulted in contour maps of sea-surface temperature and salinity with a spatial resolution of 0.5 km.

  20. Improved accuracy of the remote sensing of sea surface temperature

    NASA Technical Reports Server (NTRS)

    Dalu, G.; Prabhakara, C.; Lo, R. C.

    1981-01-01

    A method is described for determining the water vapor content to within + or - 0.4 g/sq cm from remotely sensed radiances in three infrared channels, 11, 13, 18 microns. Using this method, it is possible to significantly improve the accuracy of sea surface temperature (SST) over what is obtainable with the two channel technique. A radiative computational scheme for the radiative transfer equation is used to study the manner in which the equivalent radiative temperature of the atmosphere changes as a function of wave number for different atmospheric conditions. Average climatological conditions are used to simulate the radiative response of the atmosphere. This radiative transfer simulation is used to compute brightness temperatures for radiosonde profiles obtained from oceanographic ships, which temperatures are in turn used to estimate the SST. Nimbus 4 IRIS spectral measurements corresponding to the profiles were used in the same way for purposes of comparison.

  1. Sea-air CO2 exchange in the western Arctic coastal ocean

    NASA Astrophysics Data System (ADS)

    Evans, Wiley; Mathis, Jeremy T.; Cross, Jessica N.; Bates, Nicholas R.; Frey, Karen E.; Else, Brent G. T.; Papkyriakou, Tim N.; DeGrandpre, Mike D.; Islam, Fakhrul; Cai, Wei-Jun; Chen, Baoshan; Yamamoto-Kawai, Michiyo; Carmack, Eddy; Williams, William. J.; Takahashi, Taro

    2015-08-01

    The biogeochemical seascape of the western Arctic coastal ocean is in rapid transition. Changes in sea ice cover will be accompanied by alterations in sea-air carbon dioxide (CO2) exchange, of which the latter has been difficult to constrain owing to sparse temporal and spatial data sets. Previous assessments of sea-air CO2 flux have targeted specific subregional areas of the western Arctic coastal ocean. Here a holistic approach is taken to determine the net sea-air CO2 flux over this broad region. We compiled and analyzed an extensive data set of nearly 600,000 surface seawater CO2 partial pressure (pCO2) measurements spanning 2003 through 2014. Using space-time colocated, reconstructed atmospheric pCO2 values coupled with the seawater pCO2 data set, monthly climatologies of sea-air pCO2 differences (ΔpCO2) were created on a 0.2° latitude × 0.5° longitude grid. Sea-air CO2 fluxes were computed using the ΔpCO2 grid and gas transfer rates calculated from climatology of wind speed second moments. Fluxes were calculated with and without the presence of sea ice, treating sea ice as an imperfect barrier to gas exchange. This allowed for carbon uptake by the western Arctic coastal ocean to be assessed under existing and reduced sea ice cover conditions, in which carbon uptake increased 30% over the current 10.9 ± 5.7 Tg C (1 Tg = 1012 g) yr-1 of sea ice-adjusted exchange in the region. This assessment extends beyond previous subregional estimates in the region in an all-inclusive manner and points to key unresolved aspects that must be targeted by future research.

  2. Solar Eclipse Effect on Shelter Air Temperature

    NASA Technical Reports Server (NTRS)

    Segal, M.; Turner, R. W.; Prusa, J.; Bitzer, R. J.; Finley, S. V.

    1996-01-01

    Decreases in shelter temperature during eclipse events were quantified on the basis of observations, numerical model simulations, and complementary conceptual evaluations. Observations for the annular eclipse on 10 May 1994 over the United States are presented, and these provide insights into the temporal and spatial changes in the shelter temperature. The observations indicated near-surface temperature drops of as much as 6 C. Numerical model simulations for this eclipse event, which provide a complementary evaluation of the spatial and temporal patterns of the temperature drops, predict similar decreases. Interrelationships between the temperature drop, degree of solar irradiance reduction, and timing of the peak eclipse are also evaluated for late spring, summer, and winter sun conditions. These simulations suggest that for total eclipses the drops in shelter temperature in midlatitudes can be as high as 7 C for a spring morning eclipse.

  3. A climatology of air-sea interactions at the Mediterranean LION and AZUR buoys

    NASA Astrophysics Data System (ADS)

    Caniaux, Guy; Prieur, Louis; Bouin, Marie-Noëlle; Giordani, Hervé

    2014-05-01

    The LION and AZUR buoys (respectively at 42.1°N 4.7°E and 43.4°N 7.8°E) provide an extended data set since respectively 1999 and 2001 to present for studying air-sea interactions in the northwestern Mediterranean basin. The two buoys are located where high wind events occur (resp. north western and north easterly gale winds), that force and condition deep oceanic winter convection in that region. A short-term climatology (resp. 13 and 11 years) of air-sea interactions has been developed, which includes classical meteo-oceanic parameters, but also waves period and significant wave heights and radiative fluxes. Moreover turbulent surface fluxes have been estimated from various bulk parameterizations, in order to estimate uncertainties on fluxes. An important dispersion of turbulent fluxes is found at high wind speeds according to the parameterization used, larger than taking into account the second order effects of cool skin, warm layer and waves. An important annual cycle affects air temperatures (ATs), SSTs and turbulent fluxes at the two buoys. The annual cycle of ATs and SSTs can be well reconstructed from the first two annual harmonics, while for the turbulent heat fluxes the erratic occurrence of high and low flux events, well correlated with high/dry and low windy periods, strongly affect their annual and interannual cycles. The frequency of high surface heat fluxes and high wind stress is found highest during the autumn and winter months, despite the fact that north-westerly gale winds occur all year long at LION buoy. During calm weather period, ATs and SSTs experience an important diurnal cycle (on average 1 and 0.5°C respectively), that affect latent and sensible heat fluxes. Finally, an estimate of the interannual variability of the turbulent fluxes in Autumn and Winter is discussed, in order to characterize their potential role on deep ocean convection.

  4. Measuring important parameters for air-sea heat exchange

    NASA Astrophysics Data System (ADS)

    Garbe, Christoph; Schimpf, Uwe; Jaehne, Bernd

    2002-03-01

    The heat transfer between the ocean and the atmosphere is one of the most important parameters governing the global climate. Important parameters include the heat transfer velocity and the net heat flux as well as parameters of the underlying transport model. However, the net heat flux is hard to measure since processes take place in the thermal boundary layer, that is the topmost layer of the ocean less than 1 mm thick. Current techniques rely on three independent measurements of the constituent fluxes, the sensible heat flux, latent heat flux and radiative flux. They depend on indirect measurements of meteorological parameters and rely on a combination of data from different sensors using a number of heuristic assumptions. High relative errors and the need for long temporal averaging reduce the practicability of these techniques. In this paper a novel technique is presented that circumvents these drawbacks by directly measuring the net heat flux across the air-water interface with a single low-NETD infrared camera. A newly developed digital image processing technique allows to simultaneously estimating the surface velocity field and parameters of the temporal temperature change. In particular, this technique allows estimating the total derivative of the temperature with respect to time from a sequence of infrared images, together with error bounds on the estimates. This derivative can be used to compute the heat flux density and the heat transfer velocity, as well as the probability density function of the underlying surface renewal model. It is also possible to estimate the bulk-skin temperature difference given rise to by the net heat flux. Our technique has been successfully used in both laboratory measurements in the Heidelberg Aeolotron, as well as in field measurements in the equatorial pacific during the NOAA GasExII experiment this spring. The data show that heat flux measurements to an accuracy of better than 5% on a time scale of seconds are feasible.

  5. Late Holocene Sea Temperatures along the Central California Coast

    NASA Astrophysics Data System (ADS)

    Jones, Terry L.; Kennett, Douglas J.

    1999-01-01

    Mussel shells from central California coastal archaeological sites record changes in sea surface temperatures in the past 2000 years. Water temperatures, inferred from oxygen isotopes in the shells, were about 1°C cooler than present and stable between 2000 and 700 yr ago. Between about 700 and 500 yr ago, seasonal variation was greater than present, with extremes above and below historic levels. Water temperatures were 2-3°C cooler than today 500-300 yr ago. The interval of variable sea temperatures 700-500 yr ago partially coincided with an interval of drought throughout central California. A coincident disruption in human settlement along the coast suggests movements of people related to declining water sources. Quantities of fish bone in central coast middens dating to this same period are high relative to other periods, and the remains of northern anchovies, a species sensitive to changing oceanographic conditions, are also abundant. The continued use of local fisheries suggests that changes in settlement and diet were influenced more by drought than by a decrease in marine productivity, as fish provided a staple during an interval of low terrestrial productivity.

  6. Microwave and Electro-optical Transmission Experiments in the air-sea Boundary Layer

    NASA Astrophysics Data System (ADS)

    Anderson, K. D.

    2002-12-01

    Microwave and electro-optical signal propagation over a wind-roughened sea is strongly dependent on signal interaction with the sea surface, the mean profiles of pressure (P), humidity (Q), temperature (T), wind (U) and their turbulent fluctuations (p, q, t, u). Yet, within the marine surface layer, these mechanisms are not sufficiently understood nor has satisfactory data been taken to validate propagation models, especially under conditions of high seas, high winds, and large surface gradients of Q and T. To address this deficiency, the Rough Evaporation Duct (RED) experiment was designed to provide first data for validation of meteorological, microwave, and electro-optical models in the marine surface layer for rough surface conditions including the effects of surface waves. The RED experiment was conducted offshore of the Hawaiian Island of Oahu in late summer, mid-August to mid-September, of 2001. R/P FLIP, moored about 10 km off of the NE coast of Oahu, hosted the primary meteorological sensor suites and served as a terminus for the propagation links. There were eleven scientists and engineers aboard R/P FLIP who installed instruments measuring mean and turbulent meteorological quantities, sea wave heights, directions, and kinematics, upward and downward radiance, near surface bubble generation, atmospheric particle size distributions, laser probing of the atmosphere, and sources for both microwave and electro-optic signals. In addition to R/P FLIP, two land sites were instrumented with microwave and electro-optic receivers and meteorological sensors, two buoys were deployed, a small boat was instrumented, and two aircraft flew various tracks to sense both sea and atmospheric conditions. In all, more than 25 people from four countries, six universities, and four government agencies were directly involved with the RED experiment. While the overall outcome of the RED experiment is positive, we had a number of major and minor problems with the outfitting

  7. Comparison of MODIS Land Surface Temperature and Air Temperature over the Continental USA Meteorological Stations

    NASA Technical Reports Server (NTRS)

    Zhang, Ping; Bounoua, Lahouari; Imhoff, Marc L.; Wolfe, Robert E.; Thome, Kurtis

    2014-01-01

    The National Land Cover Database (NLCD) Impervious Surface Area (ISA) and MODIS Land Surface Temperature (LST) are used in a spatial analysis to assess the surface-temperature-based urban heat island's (UHIS) signature on LST amplitude over the continental USA and to make comparisons to local air temperatures. Air-temperature-based UHIs (UHIA), calculated using the Global Historical Climatology Network (GHCN) daily air temperatures, are compared with UHIS for urban areas in different biomes during different seasons. NLCD ISA is used to define urban and rural temperatures and to stratify the sampling for LST and air temperatures. We find that the MODIS LST agrees well with observed air temperature during the nighttime, but tends to overestimate it during the daytime, especially during summer and in nonforested areas. The minimum air temperature analyses show that UHIs in forests have an average UHIA of 1 C during the summer. The UHIS, calculated from nighttime LST, has similar magnitude of 1-2 C. By contrast, the LSTs show a midday summer UHIS of 3-4 C for cities in forests, whereas the average summer UHIA calculated from maximum air temperature is close to 0 C. In addition, the LSTs and air temperatures difference between 2006 and 2011 are in agreement, albeit with different magnitude.

  8. Assessing Air-Sea Interaction in the Evolving NASA GEOS Model

    NASA Technical Reports Server (NTRS)

    Clayson, Carol Anne; Roberts, J. Brent

    2015-01-01

    In order to understand how the climate responds to variations in forcing, one necessary component is to understand the full distribution of variability of exchanges of heat and moisture between the atmosphere and ocean. Surface heat and moisture fluxes are critical to the generation and decay of many coupled air-sea phenomena. These mechanisms operate across a number of scales and contain contributions from interactions between the anomalous (i.e. non-mean), often extreme-valued, flux components. Satellite-derived estimates of the surface turbulent and radiative heat fluxes provide an opportunity to assess results from modeling systems. Evaluation of only time mean and variability statistics, however only provides limited traceability to processes controlling what are often regime-dependent errors. This work will present an approach to evaluate the representation of the turbulent fluxes at the air-sea interface in the current and evolving Goddard Earth Observing System (GEOS) model. A temperature and moisture vertical profile-based clustering technique is used to identify robust weather regimes, and subsequently intercompare the turbulent fluxes and near-surface parameters within these regimes in both satellite estimates and GEOS-driven data sets. Both model reanalysis (MERRA) and seasonal-to-interannual coupled GEOS model simulations will be evaluated. Particular emphasis is placed on understanding the distribution of the fluxes including extremes, and the representation of near-surface forcing variables directly related to their estimation. Results from these analyses will help identify the existence and source of regime-dependent biases in the GEOS model ocean surface turbulent fluxes. The use of the temperature and moisture profiles for weather-state clustering will be highlighted for its potential broad application to 3-D output typical of model simulations.

  9. Assessing air-sea interaction in the evolving NASA GEOS model

    NASA Astrophysics Data System (ADS)

    Clayson, C. A.; Roberts, J. B.

    2014-12-01

    In order to understand how the climate responds to variations in forcing, one necessary component is to understand the full distribution of variability of exchanges of heat and moisture between the atmosphere and ocean. Surface heat and moisture fluxes are critical to the generation and decay of many coupled air-sea phenomena. These mechanisms operate across a number of scales and contain contributions from interactions between the anomalous (i.e. non-mean), often extreme-valued, flux components. Satellite-derived estimates of the surface turbulent and radiative heat fluxes provide an opportunity to assess results from modeling systems. Evaluation of only time mean and variability statistics, however only provides limited traceability to processes controlling what are often regime-dependent errors. This work will present an approach to evaluate the representation of the turbulent fluxes at the air-sea interface in the current and evolving Goddard Earth Observing System (GEOS) model. A temperature and moisture vertical profile-based clustering technique is used to identify robust weather regimes, and subsequently intercompare the turbulent fluxes and near-surface parameters within these regimes in both satellite estimates and GEOS-driven data sets. Both model reanalysis (MERRA) and seasonal-to-interannual coupled GEOS model simulations will be evaluated. Particular emphasis is placed on understanding the distribution of the fluxes including extremes, and the representation of near-surface forcing variables directly related to their estimation. Results from these analyses will help identify the existence and source of regime-dependent biases in the GEOS model ocean surface turbulent fluxes. The use of the temperature and moisture profiles for weather-state clustering will be highlighted for its potential broad application to 3-D output typical of model simulations.

  10. Three Years of Atmospheric Infrared Sounder Radiometric Calibration Validation using Sea Surface Temperatures

    NASA Technical Reports Server (NTRS)

    Aumann, H. H.; Broberg, Steve; Elliott, Denis; Gaiser, Steve; Gregorich, Dave

    2006-01-01

    This paper evaluates the absolute accuracy and stability of the radiometric calibration of the Atmospheric Infrared Sounder (AIRS) by analyzing the difference between the brightness temperatures measured at 2616 cm(exp -1) and those calculated at the top of the atmosphere (TOA), using the Real-Time Global Sea Surface Temperature (RTGSST) for cloud-free night tropical oceans between +/- 30 degrees latitude. The TOA correction is based on radiative transfer. The analysis of the first 3 years of AIRS radiances verifies the absolute calibration at 2616 cm(exp -1) to better than 200 mK, with better than 16 mK/yr stability. The AIRS radiometric calibration uses an internal full aperture wedge blackbody with the National Institute of Standards and Technology (NIST) traceable prelaunch calibration coefficients. The calibration coefficients have been unchanged since launch. The analysis uses very tight cloud filtering, which selects about 7000 cloud-free tropical ocean spectra per day, about 0.5% of the data. The absolute accuracy and stability of the radiometry demonstrated at 2616 cm(sup -1) are direct consequences of the implementation of AIRS as a thermally controlled, cooled grating-array spectrometer and meticulous attention to details. Comparable radiometric performance is inferred from the AIRS design for all 2378 channels. AIRS performance sets the benchmark for what can be achieved with a state-of-the-art hyperspectral radiometer from polar orbit and what is expected from future hyperspectral sounders. AIRS was launched into a 705 km altitude polar orbit on NASA's Earth Observation System (EOS) Aqua spacecraft on 4 May 2002. AIRS covers the 3.7-15.4 micron region of the thermal infrared spectrum with a spectral resolution of nu/Delta nu = 1200 and has returned 3.7 million spectra of the upwelling radiance each day since the start of routine data gathering in September 2002.

  11. Retrieval of air temperatures from crowd-sourced battery temperatures of cell phones

    NASA Astrophysics Data System (ADS)

    Overeem, Aart; Robinson, James; Leijnse, Hidde; Uijlenhoet, Remko; Steeneveld, Gert-Jan; Horn, Berthold K. P.

    2013-04-01

    Accurate air temperature observations are important for urban meteorology, for example to study the urban heat island and adverse effects of high temperatures on human health. The number of available temperature observations is often relatively limited. A new development is presented to derive temperature information for the urban canopy from an alternative source: cell phones. Battery temperature data were collected by users of an Android application for cell phones (opensignal.com). The application automatically sends battery temperature data to a server for storage. In this study, battery temperatures are averaged in space and time to obtain daily averaged battery temperatures for each city separately. A regression model, which can be related to a physical model, is employed to retrieve daily air temperatures from battery temperatures. The model is calibrated with observed air temperatures from a meteorological station of an airport located in or near the city. Time series of air temperatures are obtained for each city for a period of several months, where 50% of the data is for independent verification. Results are presented for Buenos Aires, London, Los Angeles, Paris, Mexico City, Moscow, Rome, and Sao Paulo. The evolution of the retrieved air temperatures often correspond well with the observed ones. The mean absolute error of daily air temperatures is less than 2 degrees Celsius, and the bias is within 1 degree Celsius. This shows that monitoring air temperatures employing an Android application holds great promise. Since 75% of the world's population has a cell phone, 20% of the land surface of the earth has cellular telephone coverage, and 500 million devices use the Android operating system, there is a huge potential for measuring air temperatures employing cell phones. This could eventually lead to real-time world-wide temperature maps.

  12. Albatrosses as Ocean Samplers of Sea Surface Temperature

    NASA Astrophysics Data System (ADS)

    Shaffer, S. A.; Kappes, M.; Tremblay, Y.; Costa, D. P.; Weber, R.; Weimerskirch, H.

    2006-12-01

    Albatrosses are unique ocean voyagers because they range so widely and travel at speeds exceeding 90 km per hour. Because they can integrate vast areas of open-ocean, albatrosses are ideal ocean samplers. Between 2003 and 2005 breeding seasons, 21 Laysan and 15 black-footed albatrosses (body mass 2.5 to 3.5 kg) were equipped with 6 g leg-mounted geolocation archival data loggers at Tern Island, French Frigate Shoals, Northwest Hawaiian Islands. The tags sampled environmental temperatures every 480 or 540 s and provided a single location per day for the duration of deployment. Whenever an albatross landed on the sea surface to feed or rest, the tag sampled sea surface temperature (SST). After nearly one year of deployment, 31 albatrosses were recaptured and 29 tags provided complete records. A total of 377,455 SST readings were obtained over 7,360 bird-days at sea. Given the location errors in the geolocation methodology (200 km) and the lack of temporal resolution (1 location per day), the SST measurements can only be used to characterize broad-scale correlates between albatross distribution and the ocean environment. However, in February 2006, we deployed 45 g GPS data loggers on 10 breeding albatrosses for 2-4 day deployments. The GPS loggers were attached to feathers on the albatrosses backs, they sampled every 10 s, and were accurate to within 10 m. One albatross was also equipped with the same leg-mounted archival tag that sampled SST every 8 s. This albatross collected 6,289 SST measurements with complementary GPS quality locations in 3 days at sea. These results highlight the efficacy of albatrosses as ocean samplers. Given that Laysan and black- footed albatrosses range throughout the North Pacific Ocean, it is conceivable that these seabirds could someday become sentinels of changing oceanic conditions. Moreover, these technologies provide exciting new information about the oceanic habitats of North Pacific albatrosses.

  13. The lithosphere-scale density and temperature configuration beneath the Barents Sea and Kara Sea region

    NASA Astrophysics Data System (ADS)

    Klitzke, Peter; Faleide, Jan Inge; Sippel, Judith; Scheck-Wenderoth, Magdalena

    2014-05-01

    major controlling factors of the thermal field, the obtained 3D density model is used to calculate the lithosphere-scale 3D conductive thermal field of the Barents Sea and Kara Sea region. Therefore, the predicted thermal field is validated with measured borehole temperatures.

  14. Late Cretaceous (late Campanian-Maastrichtian) sea-surface temperature record of the Boreal Chalk Sea

    NASA Astrophysics Data System (ADS)

    Thibault, Nicolas; Harlou, Rikke; Schovsbo, Niels H.; Stemmerik, Lars; Surlyk, Finn

    2016-02-01

    The last 8 Myr of the Cretaceous greenhouse interval were characterized by a progressive global cooling with superimposed cool/warm fluctuations. The mechanisms responsible for these climatic fluctuations remain a source of debate that can only be resolved through multi-disciplinary studies and better time constraints. For the first time, we present a record of very high-resolution (ca. 4.5 kyr) sea-surface temperature (SST) changes from the Boreal epicontinental Chalk Sea (Stevns-1 core, Denmark), tied to an astronomical timescale of the late Campanian-Maastrichtian (74 to 66 Ma). Well-preserved bulk stable isotope trends and calcareous nannofossil palaeoecological patterns from the fully cored Stevns-1 borehole show marked changes in SSTs. These variations correlate with deep-water records of climate change from the tropical South Atlantic and Pacific oceans but differ greatly from the climate variations of the North Atlantic. We demonstrate that the onset and end of the early Maastrichtian cooling and of the large negative Campanian-Maastrichtian boundary carbon isotope excursion are coincident in the Chalk Sea. The direct link between SSTs and δ13C variations in the Chalk Sea reassesses long-term glacio-eustasy as the potential driver of carbon isotope and climatic variations in the Maastrichtian.

  15. Late Cretaceous (Late Campanian-Maastrichtian) sea surface temperature record of the Boreal Chalk Sea

    NASA Astrophysics Data System (ADS)

    Thibault, N.; Harlou, R.; Schovsbo, N. H.; Stemmerik, L.; Surlyk, F.

    2015-11-01

    The last 8 Myr of the Cretaceous greenhouse interval were characterized by a progressive global cooling with superimposed cool/warm fluctuations. The mechanisms responsible for these climatic fluctuations remain a source of debate that can only be resolved through multi-disciplinary studies and better time constraints. For the first time, we present a record of very high-resolution (ca. 4.5 kyr) sea-surface temperature (SST) changes from the Boreal epicontinental Chalk Sea (Stevns-1 core, Denmark), tied to an astronomical time scale of the late Campanian-Maastrichtian (74 to 66 Myr). Well-preserved bulk stable isotope trends and calcareous nannofossil palaeoecological patterns from the fully cored Stevns-1 borehole show marked changes in SSTs. These variations correlate with deep-water records of climate change from the tropical South Atlantic and Pacific oceans but differ greatly from the climate variations of the North Atlantic. We demonstrate that the onset and end of the early Maastrichtian cooling and of the large negative Campanian-Maastrichtian boundary carbon isotope excursion are coincident in the Chalk Sea. The direct link between SSTs and δ13C variations in the Chalk Sea reassesses long-term glacio-eustasy as the potential driver of carbon isotope and climatic variations in the Maastrichtian.

  16. Sea-air of CO2 in the North Pacific using shipboard and satellite data

    NASA Technical Reports Server (NTRS)

    Stephens, Mark P.; Samuels, Geoffrey; Olson, Donald B.; Fine, Rana A.; Takahashi, Taro

    1995-01-01

    A method has been developed to produce high-resolution maps of pCO2 in surface water for the North Pacific using satellite sea surface temperature (SST) data and statistical relationships between measured pCO2 and temperature. In the subtropical North Pacific the pCO in seawater is controlled primarily by temperature. Accordingly, pCO2 values that are calculated from the satellite SST data have good agreement with the measured values (rms deviation of +/- microatm). In the northwestern subpolar region the pCO2 is controlled not only by temperature, but also by significant seasonal changes in the total CO2 concentration, which are caused by seasonal changes in primary production, mixing with subsurface waters and sea-air exchange. Consequently, the parameterization of oceanic p CO2 based on SST data alone is not totally successful in the northwestern region (rms deviation of +/- 40 microatm). The use of additional satellite products, such as wind and ocean color data, as planned for a future study, is considered necessary to account for the pCO2 variability caused by seasonal changes in the total CO2 concentration. The net CO2 flux for the area of the North Pacific included in this study (north of 10 deg N) has been calculated using the monthly pCO2 distributions computed, and monthly wind speeds from the European Centre for Medium-Range Weather Forecasts. The region is found to be a net source to the atmosphere of 1.9 x 10(exp 12) to 5.8 x 10(exp 12) moles of CO2 per year (or 0.02-0.07 Gt C/yr), most of the outflux occurring in the subtropics.

  17. Microwave Imager Measures Sea Surface Temperature Through Clouds

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image was acquired over Tropical Atlantic and U.S. East Coast regions on Aug. 22 - Sept. 23, 1998. Cloud data were collected by the Geostationary Operational Environmental Satellite (GOES). Sea Surface Temperature (SST) data were collected aboard the NASA/NASDA Tropical Rainfall Measuring Mission (TRMM) satellite by The TRMM Microwave Imager (TMI). TMI is the first satellite microwave sensor capable of accurately measuring sea surface temperature through clouds, as shown in this scene. For years scientists have known there is a strong correlation between sea surface temperature and the intensity of hurricanes. But one of the major stumbling blocks for forecasters has been the precise measurement of those temperatures when a storm begins to form. In this scene, clouds have been made translucent to allow an unobstructed view of the surface. Notice Hurricane Bonnie approaching the Carolina Coast (upper left) and Hurricane Danielle following roughly in its path (lower right). The ocean surface has been falsely colored to show a map of water temperature--dark blues are around 75oF, light blues are about 80oF, greens are about 85oF, and yellows are roughly 90oF. A hurricane gathers energy from warm waters found at tropical latitudes. In this image we see Hurricane Bonnie cross the Atlantic, leaving a cooler trail of water in its wake. As Hurricane Danielle followed in Bonnie's path, the wind speed of the second storm dropped markedly, as available energy to fuel the storm dropped off. But when Danielle left Bonnie's wake, wind speeds increased due to temperature increases in surface water around the storm. As a hurricane churns up the ocean, it's central vortex draws surface heat and water into the storm. That suction at the surface causes an upwelling of deep water. At depth, tropical ocean waters are significantly colder than water found near the surface. As they're pulled up to meet the storm, those colder waters essentially leave a footprint in the storm's wake

  18. Associations of endothelial function and air temperature in diabetic subjects

    EPA Science Inventory

    Background and Objective: Epidemiological studies consistently show that air temperature is associated with changes in cardiovascular morbidity and mortality. However, the biological mechanisms underlying the association remain largely unknown. As one index of endothelial functio...

  19. The impact of sea breeze under different synoptic patterns on air pollution within Athens basin.

    PubMed

    Mavrakou, Thaleia; Philippopoulos, Kostas; Deligiorgi, Despina

    2012-09-01

    Air quality in densely populated urban coastal areas is directly related to the coupling of the synoptic and the local scale flows. The dispersion conditions within Athens basin, under the influence of different meteorological forcings, lead to distinct spatio-temporal air pollution patterns. The aim of the current observational research is to identify and examine the effect of sea breeze under different atmospheric circulation patterns on air pollution levels for a one-year study period (2007). The study employs surface pressure maps, routine meteorological observations at two coastal sites and nitrogen monoxide (NO), nitrogen dioxide (NO(2)) and ozone (O(3)) concentrations from a network of four air quality stations within the Athens basin. A three-step methodology is applied that incorporates a set of criteria for classifying atmospheric circulation and identifying sea breeze events under each circulation pattern. Two types of sea breeze development are identified (pure sea breeze-PSB and modified sea breeze-MSB) with distinct characteristics. Sea breeze is found to develop more frequently under offshore compared to onshore and parallel to the shoreline background flows. Poor dispersion conditions (high nitrogen oxides-NO(x) and O(3) concentrations) are connected to the pure sea breeze cases and to those cases where sea breeze interacts with a moderate northerly flow during the warm period. The levels of NO(x) and O(3) for the northern Athens basin area are found to be significantly higher during the sea breeze days compared to the Etesian days. Regarding the diurnal variation of ozone for the sea breeze days, peak concentrations and higher intra-daily ranges are observed. Day-to-day pollution accumulation (build-up effect) is measured for O(3) at the northern stations in the Athens basin. PMID:22766425

  20. The comparative performance of an aviation engine at normal and high inlet air temperatures

    NASA Technical Reports Server (NTRS)

    Gardiner, Arthur W; Schey, Oscar W

    1928-01-01

    This report presents some results obtained during an investigation to determine the effect of high inlet air temperature on the performance of a Liberty 12 aviation engine. The purpose of this investigation was to ascertain, for normal service carburetor adjustments and a fixed ignition advance, the relation between power and temperature for the range of carburetor air temperatures that may be encountered when supercharging to sea level pressure at altitudes of over 20,000 feet and without intercooling when using plain aviation gasoline and mixtures of benzol and gasoline. The results show that for the conditions of test, both the brake and indicated power decrease with increase in air temperature at a faster rate than given by the theoretical assumption that power varies inversely as the square root of the absolute temperature. On a brake basis, the order of the difference in power for a temperature difference of 120 degrees F. Is 3 to 5 per cent. The observed relation between power and temperature when using the 30-70 blend was found to be linear. But, although these differences are noted, the above theoretical assumption may be considered as generally applicable except where greater precision over a wide range of temperatures is desired, in which case it appears necessary to test the particular engine under the given conditions. (author)

  1. Numerical study on the interannual oscillation of sea surface temperature in the South China Sea

    NASA Astrophysics Data System (ADS)

    Wang, Dong-Xiao; Zhou, Fa-Xiu; Fu, Gang; Qin, Zeng-Hao

    1996-03-01

    A two and a half layer oceanic model of wind-driven, thermodynamical general circulation is applied to study the interannual oscillation of sea surface temperature (SST) in the South China Sea (SCS). The model consists of two active layers: the upper mixed layer (UML) and the seasonal thermocline, with the motionless abyss beneath them. The governing equations which include momentum, continuity and sea temperature for each active layer, can describe the physics of Boussinseq approximation, reduced gravity and equatorial β-plane. The formulas for the heat flux at the surface and at the interface between two active layers are designed on the Haney scheme. The entrainment and detrainment at the bottom of the UML induces vertical transport of mass, momentum and heat, and couples of dynamic and thermodynamic effects. Using leap-frog integrating scheme and the Arakawa—C grid the model is forced by a time-dependent wind anomaly stress pattern obtained from category analysis of COADS. The numerical results indicate that there is a kind of oscillation with about 30 months period. The paper supports the opinion that the SST interannual oscillation is the oceanic response to the forcing by monsoon wind anomalies in the SCS.

  2. Estimating the Ocean Flow Field From Combined Sea Surface Temperature and Sea Surface Height Data

    NASA Technical Reports Server (NTRS)

    Stammer, Detlef

    2000-01-01

    The primary focus of this project was on the estimation 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. This effort is directly related to an attempt to describe the mechanisms which give rise to observed SST and its variability on seasonal and inter-annual timescales, its relation to ocean-atmosphere interaction, and the dynamical coupling between the ocean mixed layer and the deep interior ocean. This is one of the fundamental climate related questions being pursued currently under the CLIVAR Program. Because of the strong turbulent mixing associated with atmospheric fluxes of momentum, heat and freshwater through the sea surface, the ocean forms a shallow surface boundary layer, the mixed layer which is largely homogeneous in its constituents. The relation between the temperature of the remotely sensed "skin" and the bulk of the mixed layer is largely understood (Reynolds and Smith 1994; Emery et al., 1995). However, because the surface mixed layer is effectively decoupled from the underlying ocean dynamics, an interpretation of satellite SST observations in isolation and in direct use for dynamical studies is very difficult. As a result, the impact of SST data on the understanding of ocean variability.

  3. Sea surface and remotely sensed temperatures off Cape Mendocino, California

    NASA Technical Reports Server (NTRS)

    Breaker, L. C.; Arvesen, J. C.; Frydenlund, D.; Myers, J. S.; Short, K.

    1985-01-01

    During September 3 to 5, 1979, a multisensor oceanographic experiment was conducted off Cape Mendocino, California. The purpose of this experiment was to validate the use of remote sensing techniques over an area along the U.S. west coast where coasted upwelling is known to be intense. Remotely sensed mutlispectral data, including thermal infrared imagery, were collected above an upwelling feature off Cape Mendocino. Data were acquired from the TIRNOS-N and NOAA-6 polar orbiting satellites, the NASA Ames Research Center's high altitude U-2 aircraft, and a U.S. Coast Guard C-130 aircraft. Supporting surface truth data over the same feature were collected aboard the National Oceanic and Atmospheric Administration (NOAA) ship, OCEANOGRAPHER. Atmospheric soundings were also taken aboard the ship. The results indicate that shipboard measurements of sea surface temperatures can be reproduction within 1 C or better through remote observation of absolute infrared radiance values (whether measured aboard the NOAA polar orbiting satellite, the U-2 aircraft, or the Coast Guard aircraft) by using appropriate atmospheric corrections. Also, the patterns of sea surface temperature which were derived independently from the various remote platforms provide a consistent interpretation of the surface temperature field.

  4. Emerita analoga recruit populations and correlations with sea surface temperature

    NASA Astrophysics Data System (ADS)

    Pettway, J.; Quan, H.; Juarez, F.; Vicencio, M.; Ng, N.; Careers in Science Intern Program

    2010-12-01

    The Careers in Science program at the California Academy of Sciences is a science internship for students from groups traditionally under-represented in the sciences. Starting in 2003, interns have participated in the Farallones Marine Sanctuary Association's LiMPETS Sandy Beach Monitoring program, assessing populations of Emerita analoga, the Pacific mole crab. E. analoga, an inhabitant of intertidal swash zones along the coast from Alaska to Baja California, is an important species in the sandy beach intertidal food web. Weekly, during the months of June, July and August, a group of interns go to stairwell 18 of San Francisco’s Ocean Beach in Golden Gate National Recreational Area to systematically collect live E. analoga samples and data. Along a 50 meter sampling area, five transects with ten samples in the swash zone are taken and recorded. Collected E. analoga are sexed (male, female, female w/eggs, and recruit) and measured for carapace size. Newly settled E. analoga (recruit) populations have declined in recent years. However, beginning in 2009, recruit populations began to increase in number, particularly in 2010. Our group hypothesized that this increase in recruitment is correlated with increased sea surface temperature. It has been reported that some planktonic animals become more abundant in warmer waters after a major temperature shift. After examining the data, we did not find a correlation between sea surface temperature and recruit populations, leading us to further questions on the cause of this increase in E. analoga recruits.

  5. Reevaluation of mid-Pliocene North Atlantic sea surface temperatures

    USGS Publications Warehouse

    Robinson, Marci M.; Dowsett, Harry J.; Dwyer, Gary S.; Lawrence, Kira T.

    2008-01-01

    Multiproxy temperature estimation requires careful attention to biological, chemical, physical, temporal, and calibration differences of each proxy and paleothermometry method. We evaluated mid-Pliocene sea surface temperature (SST) estimates from multiple proxies at Deep Sea Drilling Project Holes 552A, 609B, 607, and 606, transecting the North Atlantic Drift. SST estimates derived from faunal assemblages, foraminifer Mg/Ca, and alkenone unsaturation indices showed strong agreement at Holes 552A, 607, and 606 once differences in calibration, depth, and seasonality were addressed. Abundant extinct species and/or an unrecognized productivity signal in the faunal assemblage at Hole 609B resulted in exaggerated faunal-based SST estimates but did not affect alkenone-derived or Mg/Ca–derived estimates. Multiproxy mid-Pliocene North Atlantic SST estimates corroborate previous studies documenting high-latitude mid-Pliocene warmth and refine previous faunal-based estimates affected by environmental factors other than temperature. Multiproxy investigations will aid SST estimation in high-latitude areas sensitive to climate change and currently underrepresented in SST reconstructions.

  6. Joint variability of global runoff and global sea surface temperatures

    USGS Publications Warehouse

    McCabe, G.J.; Wolock, D.M.

    2008-01-01

    Global land surface runoff and sea surface temperatures (SST) are analyzed to identify the primary modes of variability of these hydroclimatic data for the period 1905-2002. A monthly water-balance model first is used with global monthly temperature and precipitation data to compute time series of annual gridded runoff for the analysis period. The annual runoff time series data are combined with gridded annual sea surface temperature data, and the combined dataset is subjected to a principal components analysis (PCA) to identify the primary modes of variability. The first three components from the PCA explain 29% of the total variability in the combined runoff/SST dataset. The first component explains 15% of the total variance and primarily represents long-term trends in the data. The long-term trends in SSTs are evident as warming in all of the oceans. The associated long-term trends in runoff suggest increasing flows for parts of North America, South America, Eurasia, and Australia; decreasing runoff is most notable in western Africa. The second principal component explains 9% of the total variance and reflects variability of the El Ni??o-Southern Oscillation (ENSO) and its associated influence on global annual runoff patterns. The third component explains 5% of the total variance and indicates a response of global annual runoff to variability in North Aflantic SSTs. The association between runoff and North Atlantic SSTs may explain an apparent steplike change in runoff that occurred around 1970 for a number of continental regions.

  7. Ocean backscatter across the Gulf Stream sea surface temperature front

    SciTech Connect

    Nghiem, S.V.; Li, F.K.

    1997-06-01

    Ocean backscatter was measured by the Jet Propulsion Laboratory, with the airborne NUSCAT K{sub u}-band scatterometer, across the Gulf Stream sea surface temperature front during the Surface Wave Dynamics Experiment off the coast of Virginia and Maryland in the winter of 1991. Backscatter across the front between the National Oceanic and Atmospheric Administration experimental coastal buoy A (44024) on the cold side and Discus C buoy (44023) on the warm side shows a difference of more than 5 dB for vertical polarization in many cases. This large frontal backscatter change is observed in all upwind, downwind, and crosswind directions. The sea surface temperature difference measured by the buoys was about 9{degrees}C. The corresponding difference in wind speed cannot account for the large backscatter change in view of geophysical model functions depending only on neutral wind velocity such as SASS. The measured backscatter also has larger upwind-downwind and upwind-crosswind ratios compared to the model results. Furthermore, NUSCAT data reveal that upwind backscatter on the cold side was smaller than or close to crosswind backscatter on the warm side for incidence angles between 30{degrees} to 50{degrees}. This suggests that the temperature front can be detected by the scatterometer at these incidence angles for different wind directions in the cold and warm sides.

  8. Sea Surface Temperature and Vegetation Index from MODIS

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This is a composite MODIS image showing the 'green wave' of spring in North America and sea surface temperature in the ocean, collected over an 8-day period during the first week in April 2000. On land, the darker green pixels show where the most green foliage is being produced due to photosynthetic activity. Yellows on land show where there is little or no productivity and red is a boundary zone. In the ocean, orange and yellows show warmer waters and blues show colder values. (MODIS Data Type: MODIS-PFM)

  9. Middle Pliocene sea surface temperatures: A global reconstruction

    USGS Publications Warehouse

    Dowsett, H.; Barron, J.; Poore, R.

    1996-01-01

    Identification and analyses of Pliocene marine microfossils from 64 globally distributed stratigraphic sequences have been used to produce a middle Pliocene sea surface temperature reconstruction of the Earth. This reconstruction shows little or no change from current conditions in low latitude regions and significant warming of the ocean surface at mid and higher latitudes of both hemispheres. This pattern of warming is consistent with terrestrial records and suggests a combination of enhanced meridional ocean heat transport and enhanced greenhouse effect were responsible for the middle Pliocene warmth.

  10. Seasonal variations of seawater pCO2 and sea-air CO2 fluxes in a fringing coral reef, northern South China Sea

    NASA Astrophysics Data System (ADS)

    Yan, Hongqiang; Yu, Kefu; Shi, Qi; Tan, Yehui; Liu, Guohui; Zhao, Meixia; Li, Shu; Chen, Tianran; Wang, Yinghui

    2016-01-01

    Evidence based on four field surveys conducted between July 2009 and April 2011 indicates that both sea surface partial pressures of CO2 (pCO2) and sea-air CO2 fluxes at Luhuitou fringing reef in Sanya, Hainan Island, northern South China Sea (SCS) are subject to significant seasonal variations. The diurnal variation of seawater pCO2 ranges from 264 to 579 μatm in summer, which is much larger than that in autumn (152-335 μatm), in winter (84-260 μatm), and in spring (114-228 μatm). The sea-air CO2 flux in summer (˜9.6 mmol CO2 m-2 d-1) is also larger than that in other seasons (i.e.,˜3 mmol CO2 m-2 d-1 in spring, ˜3.5 mmol CO2 m-2 d-1 in autumn, and ˜2.7 mmol CO2 m-2 d-1 in winter). The atmospheric pCO2 in this reef shows small diurnal and seasonal variations. The integration of the time-series pCO2 data shows that the reef area is a weak source of atmospheric CO2 at ˜0.54 mol CO2 m-2 yr-1. Further analyses indicate that the seasonal variations of the surface seawater pCO2 in Luhuitou fringing reef are mainly affected by seasonally-dependent biological metabolic processes (organic processe and inorganic process), and that the organic process play a more important role than the inorganic process. Seasonal sea surface temperature (SST) variations and hydrodynamic processes may also have some influence on seawater pCO2 variation.

  11. Lessons Learned from AIRS: Improved Determination of Surface and Atmospheric Temperatures Using Only Shortwave AIRS Channels

    NASA Technical Reports Server (NTRS)

    Susskind, Joel

    2011-01-01

    This slide presentation reviews the use of shortwave channels available to the Atmospheric Infrared Sounder (AIRS) to improve the determination of surface and atmospheric temperatures. The AIRS instrument is compared with the Infrared Atmospheric Sounding Interferometer (IASI) on-board the MetOp-A satellite. The objectives of the AIRS/AMSU were to (1) provide real time observations to improve numerical weather prediction via data assimilation, (2) Provide observations to measure and explain interannual variability and trends and (3) Use of AIRS product error estimates allows for QC optimized for each application. Successive versions in the AIRS retrieval methodology have shown significant improvement.

  12. Simulations of The Extreme Precipitation Event Enhanced by Sea Surface Temperature Anomaly over the Black Sea

    NASA Astrophysics Data System (ADS)

    Hakan Doǧan, Onur; Önol, Barış

    2016-04-01

    Istanbul Technical University, Aeronautics and Astronautics Faculty, Meteorological Engineering, Istanbul, Turkey In this study, we examined the extreme precipitation case over the Eastern Black Sea region of Turkey by using regional climate model, RegCM4. The flood caused by excessive rain in August 26, 2010 killed 12 people and the landslides in Rize province have damaged many buildings. The station based two days total precipitation exceeds 200 mm. One of the usual suspects for this extreme event is positive anomaly of sea surface temperature (SST) over the Black Sea where the significant warming trend is clear in the last three decades. In August 2010, the monthly mean SST is higher than 3 °C with respect to the period of 1981-2010. We designed three sensitivity simulations with RegCM4 to define the effects of the Black Sea as a moisture source. The simulation domain with 10-km horizontal resolution covers all the countries bordering the Black Sea and simulation period is defined for entire August 2010. It is also noted that the spatial variability of the precipitation produced by the reference simulation (Sim-0) is consistent with the TRMM data. In terms of analysis of the sensitivity to SST, we forced the simulations by subtracting 1 °C (Sim-1), 2 °C (Sim-2) and 3 °C (Sim-3) from the ERA-Interim 6-hourly SST data (considering only the Black Sea). The sensitivity simulations indicate that daily total precipitation for all these simulations gradually decreased based on the reference simulation (Sim-0). 3-hourly maximum precipitation rates for Sim-0, Sim-1, Sim-2 and Sim-3 are 32, 25, 13 and 10.5 mm respectively over the hotspot region. Despite the fact that the simulations signal points out the same direction, degradation of the precipitation intensity does not indicate the same magnitude for all simulations. It is revealed that 2 °C (Sim-2) threshold is critical for SST sensitivity. We also calculated the humidity differences from the simulation and these

  13. Accuracy of sea ice temperature derived from the advanced very high resolution radiometer

    NASA Astrophysics Data System (ADS)

    Yu, Y.; Rothrock, D. A.; Lindsay, R. W.

    1995-03-01

    The accuracy of Arctic sea ice surface temperatures Ts derived from advanced very high resolution radiometer (AVHRR) thermal channels is evaluated in the cold seasons by comparing them with surface air temperatures Tair from drifting buoys and ice stations. We use three different estimates of satellite surface temperatures, a direct estimate from AVHRR channel 4 with only correction for the snow surface emissivity but not for the atmosphere, a single-channel regression of Ts with Tair, and Key and Haefliger's (1992) polar multichannel algorithm. We find no measurable bias in any of these estimates and few differences in their statistics. The similar performance of all three methods indicates that an atmospheric water vapor correction is not important for the dry winter atmosphere in the central Arctic, given the other sources of error that remain in both the satellite and the comparison data. The errors are not reduced by regression with both thermal channels and the satellite scan angle. A record of drifting station data shows winter air temperature to be 1.4°C wanner than the snow surface temperature. "Correcting" air temperatures to skin temperature by subtracting this amount implies that satellite Ts estimates are biased warm with respect to skin temperature by about this amount. A case study with low-flying aircraft data suggests that ice crystal precipitation can cause satellite estimates of Ts to be several degrees warmer than radiometric measurements taken close to the surface, presumably below the ice crystal precipitation layer. An analysis in which errors are assumed to exist in all measurements, not just the satellite measurements, gives a standard deviation in the satellite estimates of 0.9°C, about half the standard deviation of 1.7°C estimated by assigning all the variation between Ts and Tair to errors in Ts.

  14. Oceanic distributions and air-sea fluxes of biogenic halocarbons in the open ocean

    NASA Astrophysics Data System (ADS)

    Chuck, Adele L.; Turner, Suzanne M.; Liss, Peter S.

    2005-10-01

    Surface seawater and atmospheric concentrations of methyl iodide, chloroiodomethane, bromoform, dichlorobromomethane, and chlorodibromethane were measured during three open ocean cruises in the Atlantic and Southern oceans. The measurements spanned a longitudinal range of 115°, between 50°N and 65°S. The saturation anomalies and the instantaneous air-sea fluxes of the gases during one of these cruises (ANT XVIII/1) are presented and discussed. Methyl iodide and chloroiodomethane were highly supersaturated (>1000%) throughout the temperate and tropical regions, with calculated mean fluxes of 15 and 5.5 nmol m-2 d-1, respectively. The oceanic emissions of the brominated compounds were less substantial, and a significant area of the temperate Atlantic Ocean was found to be a sink for bromoform. Correlation analyses have been used to investigate possible controls on the concentrations of these gases. In particular, the relationship of CH3I with sea surface temperature and light is discussed, with the tentative conclusion that this compound may be formed abiotically.

  15. The effects of sea surface temperature gradients on surface turbulent fluxes

    NASA Astrophysics Data System (ADS)

    Steffen, John

    A positive correlation between sea surface temperature (SST) and wind stress perturbation near strong SST gradients (DeltaSST) has been observed in different parts of the world ocean, such as the Gulf Stream in the North Atlantic and the Kuroshio Extension east of Japan. These changes in winds and SSTs can modify near-surface stability, surface stress, and latent and sensible heat fluxes. In general, these small scale processes are poorly modeled in Numerical Weather Prediction (NWP) and climate models. Failure to account for these air--sea interactions produces inaccurate values of turbulent fluxes, and therefore a misrepresentation of the energy, moisture, and momentum budgets. Our goal is to determine the change in these surface turbulent fluxes due to overlooking the correlated variability in winds, SSTs, and related variables. To model these air--sea interactions, a flux model was forced with and without SST--induced changes to the surface wind fields. The SST modification to the wind fields is based on a baroclinic argument as implemented by the University of Washington Planetary Boundary-Layer (UWPBL) model. Other input parameters include 2-m air temperature, 2-m dew point temperature, surface pressure (all from ERA--interim), and Reynolds Daily Optimum Interpolation Sea Surface Temperature (OISST). Flux model runs are performed every 6 hours starting in December 2002 and ending in November 2003. From these model outputs, seasonal, monthly, and daily means of the difference between DeltaSST and no DeltaSST effects on sensible heat flux (SHF), latent heat flux (LHF), and surface stress are calculated. Since the greatest impacts occur during the winter season, six additional December-January-February (DJF) seasons were analyzed for 1987--1990 and 1999--2002. The greatest differences in surface turbulent fluxes are concentrated near strong SST fronts associated with the Gulf Stream and Kuroshio Extension. On average, 2002---2003 DJF seasonal differences in SHF

  16. Effect of Initial Mixture Temperature on Flame Speed of Methane-Air, Propane-Air, and Ethylene-Air Mixtures

    NASA Technical Reports Server (NTRS)

    Dugger, Gordon L

    1952-01-01

    Flame speeds based on the outer edge of the shadow cast by the laminar Bunsen cone were determined as functions of composition for methane-air mixtures at initial mixture temperatures ranging from -132 degrees to 342 degrees c and for propane-air and ethylene-air mixtures at initial mixture temperatures ranging from -73 degrees to 344 degrees c. The data showed that maximum flame speed increased with temperature at an increasing rate. The percentage change in flame speed with change in initial temperature for the three fuels followed the decreasing order, methane, propane, and ethylene. Empirical equations were determined for maximum flame speed as a function of initial temperature over the temperature range covered for each fuel. The observed effect of temperature on flame speed for each of the fuels was reasonably well predicted by either the thermal theory as presented by Semenov or the square-root law of Tanford and Pease.

  17. Tropical Intraseasonal Air-Sea Exchanges during the 1997 Pacific Warming

    NASA Technical Reports Server (NTRS)

    Sui, C.-H.; Lau, K.-M.; Chou, S.-H.; Wang, Zihou

    1999-01-01

    The Madden Julian Oscillations (MJO) and associated westerly wind (WW) events account for much of the tropical intraseasonal variability (TISV). The TISV has been suggested as an important stochastic forcing that may be one of the underlying causes for the observed irregularities of the El Nino-Southern Oscillation (ENSO). Recent observational studies and theories of interannual to interdecadal-scale variability suggest that ENSO may arise from different mechanisms depending on the basic states. The Pacific warming event of 1997, being associated with a period of strong MJO and WW events, serves as a natural experiment for studying the possible role of TISV in triggering an ENSO event. We have performed a combined statistical and composite analysis of surface WW events based on the assimilated surface wind and sea level pressure for the period of 1980-1993, the SSM/I wind for the period of 1988-1997, and OLR. Results indicates that extratropical forcing contribute significantly to the evolution of MJO and establishment of WW events over the Pacific warm pool. Following the major WW events, there appeared an eastward extension of equatorial warm SST anomalies from the western Pacific warm pool. Such tropical-extratropical interaction is particularly clear in the winter of 96-97 that leads to the recent warming event in 1997/98. From the above discussion, our current study on this subject is based on the hypothesis that 1) there is an enhanced air-sea interaction associated with TISV and the northerly surges from the extratropics in the initial phase of the 97/98 warming event, and 2) the relevant mechanisms are functions of the basic state of the coupled system (in terms of SST distribution and atmospheric mean circulation) that varies at the interannual and interdecadal time scale. We are analyzing the space-time structure of the northerly surges, their association with air-sea fluxes and upper ocean responses during the period of September 1996 to June 1997. The

  18. Temporal and spatial variations of sea surface temperature in the East China Sea

    NASA Astrophysics Data System (ADS)

    Tseng, Chente; Lin, Chiyuan; Chen, Shihchin; Shyu, Chungzen

    2000-03-01

    Sea surface temperature of the East China Sea (ECS) were analyzed using the NOAA/AVHRR SST images. These satellite images reveal surface features of ECS including mainly the Kuroshio Current, Kuroshio Branch Current, Taiwan Warm Current, China coastal water, Changjiang diluted water and Yellow Sea mixed cold water. The SST of ECS ranges from 27 to 29°C in summer; some cold eddies were found off northeast Taiwan and to the south of Changjiang mouth. SST anomalies at the center of these eddies were about 2-5°C. The strongest front usually occurs in May each year and its temperature gradient is about 5-6°C over a cross-shelf distance of 30 nautical miles. The Yellow Sea mixed cold water also provides a contrast from China Coastal waters shoreward of the 50 m isobath; cross-shore temperature gradient is about 6-8°C over 30 nautical miles. The Kuroshio intrudes into ECS preferably at two locations. The first is off northeast Taiwan; the subsurface water of Kuroshio is upwelled onto the shelf while the main current is deflected seaward. The second site is located at 31°N and 128°E, which is generally considered as the origin of the Tsushima Warm Current. More quantitatively, a 2-year time series of monthly SST images is examined using EOF analysis to determine the spatial and temporal variations in the northwestern portion of ECS. The first spatial EOF mode accounts for 47.4% of total spatial variance and reveals the Changjiang plume and coastal cold waters off China. The second and third EOF modes account for 16.4 and 9.6% of total variance, respectively, and their eigenvector images show the intrusion of Yellow Sea mixed cold waters and the China coastal water. The fourth EOF mode accounts for 5.4% of total variance and reveals cold eddies around Chusan Islands. The temporal variance EOF analysis is less revealing in this study area.

  19. Sea ice, winter convection, and the temperature minimum layer in the Southern Ocean

    SciTech Connect

    Toole, J.M.

    1981-09-20

    The structure of the near surface waters in the Southern Ocean, poleward of the Antarctic Polar Front but away from continental margins, is investigated with a three-dimensional time-dependent numerical model which resolves the annual sea ice cycle. The growth and decay of the ice field is predicted, using one of Semtner's (1976) thermodynamic ice models, in terms of specified atmospheric data and computed thermohaline characteristics of the ocean layers. The ice field is found to be sensitive to the lateral advection of heat by the oceanic circulation as well as vertical heat transports due to deep winter convection. The model treats the temperature minimum layer in the Southern Ocean as the remnant of a deep winter mixed layer which becomes capped by surface heating and precipitation in summer. The predicted thermohaline characteristics of the temperature minimum layer and the surface mixed layer are in good agreement with observations. Finally, the annual air-sea heat exchange predicted by the model is discussed. The model's predicted area averaged heat loss experienced by the ocean south of the Atlantic Polar Front is much smaller than was previously estimated. This is attributed to errors in the southern region of the model domain. It is suggested that models, which include the interactions between sea ice and surface, deep, and bottom waters along the continental margins, are needed to investigate this region.

  20. Distributions and air-sea fluxes of carbon dioxide in the Western Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Gao, Zhongyong; Chen, Liqi; Sun, Heng; Chen, Baoshan; Cai, Wei-Jun

    2012-12-01

    The uptake of carbon dioxide (CO2) by the Arctic Ocean is most likely increasing because of the rapid sea-ice retreat that lifted the barriers preventing gas exchange and light penetration for biological growth. Measurements of atmospheric and surface sea water partial pressure of CO2 (pCO2) were conducted during the Chinese National Arctic Research Expedition (CHINARE) cruises from July to September in 2003 and 2008. The latitudinal distribution of pCO2 along the 169°W transect showed a below-atmopsheric pCO2 level in most of the Western Arctic Ocean, with distinct regional differences from Bering Strait northward to the Central Acrctic Ocean. The average air-sea CO2 fluxes on the shelf and slope of the Chukchi Sea were -17.0 and -8.1 mmol m-2 d-1 respectively. In the ice-free zone, the partially ice-covered zone, and the heavily ice-covered zone of the Canada Basin, the fluxes were -4.2, -8.6, -2.5 mmol m-2 d-1 respectively. These rates are lower than other recent estimates. Our new results not only confirmed previous observations that most areas of the Western Arctic Ocean were a CO2 sink in general, but they also revealed that the previously unsampled central basins were a moderate CO2 sink. Analysis of controlling factors in different areas shows that pCO2 in Bering Strait was influenced not only by the Bering inflow waters but also by the high biological production. However, pCO2 fluctuated sharply because of strong water mixing both laterally and vertically. In the marginal ice zone (Chukchi Sea), pCO2 was controlled by ice melt and biological production, both of which would decrease pCO2 onshore of the ice edge. In the nearly ice-free southern Canada Basin, pCO2 increasd latitudinally as a result of atmospheric CO2 uptake due to intensive gas exchange, increased temperature, and decresed biological CO2 uptake due to limited nutrient supply. Finally, pCO2 was moderately lower than the atmospheric value and was relatively stable under the ice sheet of the

  1. Biofilm-like properties of the sea surface and predicted effects on air-sea CO2 exchange

    NASA Astrophysics Data System (ADS)

    Wurl, Oliver; Stolle, Christian; Van Thuoc, Chu; The Thu, Pham; Mari, Xavier

    2016-05-01

    Because the sea surface controls various interactions between the ocean and the atmosphere, it has a profound function for marine biogeochemistry and climate regulation. The sea surface is the gateway for the exchange of climate-relevant gases, heat and particles. Thus, in order to determine how the ocean and the atmosphere interact and respond to environmental changes on a global scale, the characterization and understanding of the sea surface are essential. The uppermost part of the water column is defined as the sea-surface microlayer and experiences strong spatial and temporal dynamics, mainly due to meteorological forcing. Wave-damped areas at the sea surface are caused by the accumulation of surface-active organic material and are defined as slicks. Natural slicks are observed frequently but their biogeochemical properties are poorly understood. In the present study, we found up to 40 times more transparent exopolymer particles (TEP), the foundation of any biofilm, in slicks compared to the underlying bulk water at multiple stations in the North Pacific, South China Sea, and Baltic Sea. We found a significant lower enrichment of TEP (up to 6) in non-slick sea surfaces compared to its underlying bulk water. Moreover, slicks were characterized by a large microbial biomass, another shared feature with conventional biofilms on solid surfaces. Compared to non-slick samples (avg. pairwise similarity of 70%), the community composition of bacteria in slicks was increasingly (avg. pairwise similarity of 45%) different from bulk water communities, indicating that the TEP-matrix creates specific environments for its inhabitants. We, therefore, conclude that slicks can feature biofilm-like properties with the excessive accumulation of particles and microbes. We also assessed the potential distribution and frequency of slick-formation in coastal and oceanic regions, and their effect on air-sea CO2 exchange based on literature data. We estimate that slicks can reduce CO2

  2. [Prediction of high temperature harm to rice in Jiangsu Province based on sea surface temperature].

    PubMed

    Pan, Ao-Da; Gao, Ping; Liu, Mei; Wang, Chun-Yi

    2010-01-01

    Based on the measurements of rice growth and the ordinary meteorological observations from eight main agro-meteorological stations in Jiangsu Province in 1986-2007, this paper analyzed the characteristics of generation circulation corresponding to the abnormal strong and southern subtropical high pressure in 2003 (the year with a typically high temperature), the relationships between the abnormalities of subtropical high pressure and previous sea surface temperature, and the physiological responses of rice to the abnormal high temperature during its crucial development stages. In the meantime, a field correlation analysis was made on the relationships between the harm index of high temperature in the northern (Huaibei), middle (Jianghuai), and southern (Sunan) areas of Jiangsu and the sea surface temperature (SST) of Western Pacific. The results showed that the harm index of high temperature in the three areas was highly correlated with the SST of Nino area, northern area, and warm pool area of Western Pacific, respectively, but the significance and temporal evolution of the correlations varied among the areas. The transformation of SST was conducted to optimize its correlation with the harm index of high temperature, and an increased reliability of SST acting as a predictor of high temperature harm was obtained. The simulation results of the established models in predicting high temperature harm to rice in Huaibei, Jianghuai and Sunan areas of Jiangsu Province were significant at 0.01 level. PMID:20387435

  3. Quantifying air-sea gas exchange using noble gases in a coastal upwelling zone

    NASA Astrophysics Data System (ADS)

    Manning, C. C.; Stanley, R. H. R.; Nicholson, D. P.; Squibb, M. E.

    2016-05-01

    The diffusive and bubble-mediated components of air-sea gas exchange can be quantified separately using time-series measurements of a suite of dissolved inert gases. We have evaluated the performance of four published air-sea gas exchange parameterizations using a five-day time-series of dissolved He, Ne, Ar, Kr, and Xe concentration in Monterey Bay, CA. We constructed a vertical model including surface air-sea gas exchange and vertical diffusion. Diffusivity was measured throughout the cruise from profiles of turbulent microstructure. We corrected the mixed layer gas concentrations for an upwelling event that occurred partway through the cruise. All tested parameterizations gave similar results for Ar, Kr, and Xe; their air-sea fluxes were dominated by diffusive gas exchange during our study. For He and Ne, which are less soluble, and therefore more sensitive to differences in the treatment of bubble-mediated exchange, the parameterizations gave widely different results with respect to the net gas exchange flux and the bubble flux. This study demonstrates the value of using a suite of inert gases, especially the lower solubility ones, to parameterize air-sea gas exchange.

  4. Surface wave effects on water temperature in the Baltic Sea: simulations with the coupled NEMO-WAM model

    NASA Astrophysics Data System (ADS)

    Alari, Victor; Staneva, Joanna; Breivik, Øyvind; Bidlot, Jean-Raymond; Mogensen, Kristian; Janssen, Peter

    2016-06-01

    Coupled circulation (NEMO) and wave model (WAM) system was used to study the effects of surface ocean waves on water temperature distribution and heat exchange at regional scale (the Baltic Sea). Four scenarios—including Stokes-Coriolis force, sea-state dependent energy flux (additional turbulent kinetic energy due to breaking waves), sea-state dependent momentum flux and the combination these forcings—were simulated to test the impact of different terms on simulated temperature distribution. The scenario simulations were compared to a control simulation, which included a constant wave-breaking coefficient, but otherwise was without any wave effects. The results indicate a pronounced effect of waves on surface temperature, on the distribution of vertical temperature and on upwelling's. Overall, when all three wave effects were accounted for, did the estimates of temperature improve compared to control simulation. During the summer, the wave-induced water temperature changes were up to 1 °C. In northern parts of the Baltic Sea, a warming of the surface layer occurs in the wave included simulations in summer months. This in turn reduces the cold bias between simulated and measured data, e.g. the control simulation was too cold compared to measurements. The warming is related to sea-state dependent energy flux. This implies that a spatio-temporally varying wave-breaking coefficient is necessary, because it depends on actual sea state. Wave-induced cooling is mostly observed in near-coastal areas and is the result of intensified upwelling in the scenario, when Stokes-Coriolis forcing is accounted for. Accounting for sea-state dependent momentum flux results in modified heat exchange at the water-air boundary which consequently leads to warming of surface water compared to control simulation.

  5. Surface wave effects on water temperature in the Baltic Sea: simulations with the coupled NEMO-WAM model

    NASA Astrophysics Data System (ADS)

    Alari, Victor; Staneva, Joanna; Breivik, Øyvind; Bidlot, Jean-Raymond; Mogensen, Kristian; Janssen, Peter

    2016-08-01

    Coupled circulation (NEMO) and wave model (WAM) system was used to study the effects of surface ocean waves on water temperature distribution and heat exchange at regional scale (the Baltic Sea). Four scenarios—including Stokes-Coriolis force, sea-state dependent energy flux (additional turbulent kinetic energy due to breaking waves), sea-state dependent momentum flux and the combination these forcings—were simulated to test the impact of different terms on simulated temperature distribution. The scenario simulations were compared to a control simulation, which included a constant wave-breaking coefficient, but otherwise was without any wave effects. The results indicate a pronounced effect of waves on surface temperature, on the distribution of vertical temperature and on upwelling's. Overall, when all three wave effects were accounted for, did the estimates of temperature improve compared to control simulation. During the summer, the wave-induced water temperature changes were up to 1 °C. In northern parts of the Baltic Sea, a warming of the surface layer occurs in the wave included simulations in summer months. This in turn reduces the cold bias between simulated and measured data, e.g. the control simulation was too cold compared to measurements. The warming is related to sea-state dependent energy flux. This implies that a spatio-temporally varying wave-breaking coefficient is necessary, because it depends on actual sea state. Wave-induced cooling is mostly observed in near-coastal areas and is the result of intensified upwelling in the scenario, when Stokes-Coriolis forcing is accounted for. Accounting for sea-state dependent momentum flux results in modified heat exchange at the water-air boundary which consequently leads to warming of surface water compared to control simulation.

  6. A high-resolution global sea surface temperature climatology

    SciTech Connect

    Reynolds, R.W.; Smith, T.M.

    1995-06-01

    In response to the development of a new higher-resolution sea surface temperature (SST) analysis at the National Meteorological Center (NMC), a new monthly 1{degrees} global sea surface temperature climatology was constructed from two intermediate climatologies: the 2{degrees} SST climatology used a 30-yr 1950-1979 base period between roughly 40{degrees}S and 60{degrees}N based on in situ (ship and buoy) SST data supplemented by four years (1982-1985) of satellite SST retrievals, and sea-ice coverage data over a 12-yr period (1982-1993). The final climatology was combined from these two products so that a 1{degrees} resolution was maintained and the base period was adjusted to the 1950-1979 period wherever possible (approximately between 40{degrees}S and 60{degrees}N). Compared to the 2{degrees} climatology, the 1{degrees} climatology resolves equatorial upwelling and fronts much better. This leads to a better matching of the scales of the new analysis and climatology. In addition, because the magnitudes of large-scale features are consistently maintained in both the older 2{degrees} and the new 1{degrees} climatologies, climate monitoring of large-scale anomalies will be minimally affected by the analysis change. The use of 12 years of satellite SST retrievals makes this new climatology useful for many additional purposes because its effective resolution actually approaches 1{degrees} everywhere over the global ocean and because the mean SST values are more accurate south of 40{degrees}S than climatologies without these data. 12 refs., 16 figs.

  7. Air moisture control on ocean surface temperature, hidden key to the warm bias enigma

    NASA Astrophysics Data System (ADS)

    Hourdin, Frédéric; Gǎinusǎ-Bogdan, Alina; Braconnot, Pascale; Dufresne, Jean-Louis; Traore, Aboul-Khadre; Rio, Catherine

    2015-12-01

    The systematic overestimation by climate models of the surface temperature over the eastern tropical oceans is generally attributed to an insufficient oceanic cooling or to an underestimation of stratocumulus clouds. We show that surface evaporation contributes as much as clouds to the dispersion of the warm bias intensity in a multimodel simulations ensemble. The models with the largest warm biases are those with the highest surface heating by radiation and lowest evaporative cooling in atmospheric simulations with prescribed sea surface temperatures. Surface evaporation also controls the amplitude of the surface temperature response to this overestimated heating, when the atmosphere is coupled to an ocean. Evaporation increases with temperature both because of increasing saturation humidity and of an unexpected drying of the near-surface air. Both the origin of the bias and this temperature adjustment point to the key role of near-surface relative humidity and its control by the atmospheric model.

  8. Sensitivity of tropical cyclone intensity to sea surface temperature

    SciTech Connect

    Evans, J.L. )

    1993-06-01

    Increased occurrence of more intense tropical storms intruding further poleward has been foreshadowed as one of the potential consequences of global warming. This scenario is based almost entirely on the general circulation model predictions of warmer sea surface temperature (SST) with increasing levels of atmospheric CO[sub 2] and some theories of tropical cyclone intensification that support the notion of more intense systems with warmer SST. Whether storms are able to achieve this theoretically determined more intense state depends on whether the temperature of the underlying water is the dominant factor in tropical cyclone intensification. An examination of the historical data record in a number of ocean basins is used to identify the relative importance of SST in the tropical cyclone intensification process. The results reveal that SST alone is an inadequate predictor of tropical cyclone intensity. Other factors known to affect tropical cyclone frequency and intensity are discussed. 16 refs., 6 figs., 3 tabs.

  9. Correlations between altimetric sea surface height and radiometric sea surface temperature in the South Atlantic

    NASA Astrophysics Data System (ADS)

    Jones, Matthew S.; Allen, Myles; Guymer, Trevor; Saunders, Mark

    1998-04-01

    In the last decade, satellite altimetric measurements of sea surface height (SSH) and infrared radiometric measurements of sea surface temperature (SST) have provided a wealth of information about ocean circulation and atmosphere-ocean interactions. SSH is a depth-integrated quantity dependent upon the temperature and salinity structure of the water column and on the depth independent barotropic contribution. SST from infrared radiometers is a surface parameter representing the temperature of the top few microns of the ocean surface. Hence any relationship between SST and SSH provides dynamical information about the coupling between the ocean surface and subsurface. It also offers a promise of new techniques such as interpolating SSH data using SST and of improved calculations of eddy kinetic energy. We use SST data from the along-track scanning radiometer on ERS-I and SSH data from the TOPEX/POSEIDON instrument to examine the relationship between SST and SSH anomalies within the South Atlantic region for 1993 and 1994. We find that positive (≈0.2-0.6) spatial cross correlations between SST and SSH anomalies at zero lag are present throughout the region at large scales (wavelengths >1000 km). Small-scale correlations, however, are high (≈0.7) only in areas associated with fronts and mesoscale variability. These small-scale correlations are seasonal, being strongest in winter and weakest in summer. We discuss the application of these correlations to various techniques requiring the synergistic use of SSH and SST data.

  10. Estimation Accuracy of air Temperature and Water Vapor Amount Above Vegetation Canopy Using MODIS Satellite Data

    NASA Astrophysics Data System (ADS)

    Tomosada, M.

    2005-12-01

    Estimation accuracy of the air temperature and water vapor amount above vegetation canopy using MODIS satellite data is indicated at AGU fall meeting. The air temperature and water vapor amount which are satisfied the multilayer energy budget model from the ground surface to the atmosphere are estimated. Energy budget models are described the fluxes of sensible heat and latent heat exchange for the ground surface and the vegetated surface. Used MODIS satellite data is the vegetated surface albedo which is calculated from visible and near infrared band data, the vegetated surface temperature, NDVI (Normalized Difference Vegetation Index), LAI (Leaf Area Index). Estimation accuracy of air temperature and water vapor amount above vegetation canopy is evaluated comparing with the value which is measured on a flux research tower in Tomakomai northern forest of Japan. Meteorological parameters such as temperature, wind speed, water vapor amount, global solar radiation are measured on a flux tower from the ground to atmosphere. Well, MODIS satellite observes at day and night, and it snows in Tomakomai in winter. Therefore, estimation accuracy is evaluated dividing on at daytime, night, snowfall day, and not snowfall day. There is the investigation of the undeveloped region such as dense forest and sea in one of feature of satellite observation. Since there is almost no meteorological observatory at the undeveloped region so far, it is hard to get the meteorological parameters. Besides, it is the one of the subject of satellite observation to get the amount of physical parameter. Although the amount of physical parameter such as surface temperature and concentration of chlorophyll-a are estimated by satellite, air temperature and amount of water vapor above vegetation canopy have not been estimated by satellite. Therefore, the estimation of air temperature and water vapor amount above vegetation canopy using satellite data is significant. Further, a highly accurate

  11. Global interoperability in the oceanographic sea surface temperature community

    NASA Astrophysics Data System (ADS)

    Armstrong, E. M.; Casey, K. S.; Vazquez, J.; Habermann, T.; Bingham, A.; Thompson, C. K.; Donlon, C. J.

    2010-12-01

    The Group for High Resolution Sea Surface Temperature (GHRSST) Project is an international consortium of data providers coordinated across four continents providing sea surface temperature (SST) products from nearly every SST observing satellite in common data and metadata formats since 2005. It currently provides Level 2P data for 13 unique sensors with over 40 combined Level 2, 3 and 4 products. The entire project produces on the order of 35 Gbytes/day and distributes over 3 Tbytes/ month from a variety of access nodes. Although these combined data throughputs are modest by the standards of future NASA Decadal missions, GHRSST has achieved a large measure of success by implementing a regional/global task sharing framework built on self describing data formats, standardized metadata content and data access protocols early in its mission. We will present some of these implementation strategies, lessons learned and history with regard to standardizing products while reducing barriers to interoperability that the project undertook leading up to the present. We will also discuss recent revisions of data and metadata product specifications, and new tools and services that the project will implement in the near future to further reduce barriers, and improve discovery, metadata and access.

  12. A multiproxy reconstruction of Hebridean Shelf Sea spring sea surface temperatures from 1805-2010 (Invited)

    NASA Astrophysics Data System (ADS)

    Reynolds, D.; Butler, P.; Williams, S.; Scourse, J. D.; Richardson, C.; Wanamaker, A. D.; Austin, W.; Cage, A.; Sayer, M.

    2013-12-01

    We present a multiproxy reconstruction of Hebridean shelf sea (Tiree Passage; NW Scotland) spring sea surface temperatures (SSTs) for the period AD 1805-2010. The reconstruction is based on growth increment series from the first absolutely dated annually-resolved multi-centennial Glycymeris glycymeris bivalve mollusc sclerochronology and is coupled with previously published stable oxygen isotopes (δ18O) from benthic foraminifera sampled from a dated sediment core from nearby Loch Sunart. The independent series contain significant correlations with SSTs across complementary frequency domains. The low frequency component of the sedimentary archive was combined with the mid and high frequency components of the G. glycymeris chronology indices to create a single multiproxy series. Split calibration-verification statistics (reduction of error, RE, coefficient of efficiency, CE, and R2) indicate that the multiproxy record, calibrated to local instrumental sea surface temperatures, contains significant precision and skill at reconstructing spring SSTs (RE=0.59, CE=0.26, R2=0.54). These data demonstrate that bivalve sclerochronologies, when combined with low frequency proxies such as sediment archives, can facilitate statistically robust reconstructions of palaeoceanographic variability over the late Holocene for hydrographically-significant regions of the temperate marine system previously void of annually-resolved archives. The reconstructed SSTs contain a general warming trend of 0.60 ×0.14oC per century. Only four years in the reconstructed period (1999, 2000, 2002 and 2003) exceed temperatures greater than two standard deviations higher than the reconstructed mean SST (9.03oC), whilst just three years in the first half of the 19th century (1835, 1838 and 1840) fall more than 2σ below the reconstructed mean (6.80oC).

  13. A physically based analytical spatial air temperature and humidity model

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Endreny, Theodore A.; Nowak, David J.

    2013-09-01

    Spatial variation of urban surface air temperature and humidity influences human thermal comfort, the settling rate of atmospheric pollutants, and plant physiology and growth. Given the lack of observations, we developed a Physically based Analytical Spatial Air Temperature and Humidity (PASATH) model. The PASATH model calculates spatial solar radiation and heat storage based on semiempirical functions and generates spatially distributed estimates based on inputs of topography, land cover, and the weather data measured at a reference site. The model assumes that for all grids under the same mesoscale climate, grid air temperature and humidity are modified by local variation in absorbed solar radiation and the partitioning of sensible and latent heat. The model uses a reference grid site for time series meteorological data and the air temperature and humidity of any other grid can be obtained by solving the heat flux network equations. PASATH was coupled with the USDA iTree-Hydro water balance model to obtain evapotranspiration terms and run from 20 to 29 August 2010 at a 360 m by 360 m grid scale and hourly time step across a 285 km2 watershed including the urban area of Syracuse, NY. PASATH predictions were tested at nine urban weather stations representing variability in urban topography and land cover. The PASATH model predictive efficiency R2 ranged from 0.81 to 0.99 for air temperature and 0.77 to 0.97 for dew point temperature. PASATH is expected to have broad applications on environmental and ecological models.

  14. Energy consumption and temperature correlations for 4 Greek Ionian Sea islands

    NASA Astrophysics Data System (ADS)

    Psiloglou, B.; Giannakopoulos, C.; Dagoumas, A.; Skourtis, K.

    2012-04-01

    Energy consumption, especially for space heating and cooling, is linked to several weather variables, mainly air temperature. This study investigates the relationship between residential energy consumption load demand and daily mean air temperature for 4 Greek islands in the Ionian Sea for the period 2005-2011.These islands are Zante, Cephallonia, Corfu and Lefkada and were selected due to their data availability as they are interconnected to the mainland power distribution system. We present the time series of diurnal, daily, monthly and yearly variations of energy consumption for each of the selected sites and subsequently identify correlations with mean daily air temperature. Several effects such as weekly and holiday effects, unrelated to weather conditions, can be detected. Daily and monthly seasonal effects have been studied separately to isolate the weather influence on energy consumption. The most important finding, however, is the outstanding increase in consumption during the tourism season. Depending on the island, increased levels of consumption are present for 4,5 or more months per year, related to tourists arrivals on the island. This effect combined with energy consumption peaks on the hot days of the year should be taken into account during energy conservation planning.

  15. Decadal trends in air-sea CO2 exchange in the Ross Sea (Antarctica)

    NASA Astrophysics Data System (ADS)

    Tagliabue, Alessandro; Arrigo, Kevin R.

    2016-05-01

    Highly productive Antarctic shelf systems, like the Ross Sea, play important roles in regional carbon budgets, but the drivers of local variations are poorly quantified. We assess the variability in the Ross Sea carbon cycle using a regional physical-biogeochemical model. Regionally, total partial pressure of CO2 (pCO2) increases are largely controlled by the biological pump and broadly similar to those in the offshore Southern Ocean. However, this masks substantial local variability within the Ross Sea, where interannual fluctuations in total pCO2 are driven by the biological pump and alkalinity, whereas those for anthropogenic pCO2 are related to physical processes. Overall, the high degree of spatial variability in the Ross Sea carbon cycle causes extremes in aragonite saturation that can be as large as long-term trends. Therefore, Antarctic shelf polynya systems like the Ross Sea will be strongly affected by local processes in addition to larger-scale phenomena.

  16. Equipment for Measuring Air Flow, Air Temperature, Relative Humidity, and Carbon Dioxide in Schools. Technical Bulletin.

    ERIC Educational Resources Information Center

    Jacobs, Bruce W.

    Information on equipment and techniques that school facility personnel may use to evaluate IAQ conditions are discussed. Focus is placed on the IAQ parameters of air flow, air temperature, relative humidity, as well as carbon dioxide and the equipment used to measure these factors. Reasons for measurement and for when the measurement of these…

  17. Impact of sea surface temperature front on stratus-sea fog over the Yellow and East China Seas — a case study with implications for climatology

    NASA Astrophysics Data System (ADS)

    Li, Man; Zhang, Suping

    2013-06-01

    A stratus-sea fog event that occurred over the Yellow and East China Seas on 3 June 2011 is investigated using observations and a numerical model, with a focus on the effects of background circulation and Sea Surface Temperature Front (SSTF) on the transition of stratus into sea fog. Southerly winds of a synoptic high-pressure circulation transport water vapor to the Yellow Sea, creating conditions favorable for sea fog/stratus formation. The subsidence from the high-pressure contributes to the temperature inversion at the top of the stratus. The SSTF forces a secondary circulation within the ABL (Atmospheric Boundary Layer), the sinking branch of which on the cold flank of SSTF helps lower the stratus layer further to reach the sea surface. The cooling effect over the cold sea surface counteracts the adiabatic warming induced by subsidence. The secondary circulation becomes weak and the fog patches are shrunk heavily with the smoothed SSTF. A conceptual model is proposed for the transition of stratus into sea fog over the Yellow and East China Seas. Finally, the analyses suggest that sea fog frequency will probably decrease due to the weakened SSTF and the reduced subsidence of secondary circulation under global warming.

  18. The influence of sea ice cover on air-sea gas exchange estimated with radon-222 profiles

    NASA Astrophysics Data System (ADS)

    Rutgers van der Loeff, Michiel M.; Cassar, Nicolas; Nicolaus, Marcel; Rabe, Benjamin; Stimac, Ingrid

    2014-05-01

    Air-sea gas exchange plays a key role in the cycling of greenhouse and other biogeochemically important gases. Although air-sea gas transfer is expected to change as a consequence of the rapid decline in summer Arctic sea ice cover, little is known about the effect of sea ice cover on gas exchange fluxes, especially in the marginal ice zone. During the Polarstern expedition ARK-XXVI/3 (TransArc, August/September 2011) to the central Arctic Ocean, we compared 222Rn/226Ra ratios in the upper 50 m of 14 ice-covered and 4 ice-free stations. At three of the ice-free stations, we find 222Rn-based gas transfer coefficients in good agreement with expectation based on published relationships between gas transfer and wind speed over open water when accounting for wind history from wind reanalysis data. We hypothesize that the low gas transfer rate at the fourth station results from reduced fetch due to the proximity of the ice edge, or lateral exchange across the front at the ice edge by restratification. No significant radon deficit could be observed at the ice-covered stations. At these stations, the average gas transfer velocity was less than 0.1 m/d (97.5% confidence), compared to 0.5-2.2 m/d expected for open water. Our results show that air-sea gas exchange in an ice-covered ocean is reduced by at least an order of magnitude compared to open water. In contrast to previous studies, we show that in partially ice-covered regions, gas exchange is lower than expected based on a linear scaling to percent ice cover.

  19. Sea breeze forcing of estuary turbulence and air-water CO2 exchange

    NASA Astrophysics Data System (ADS)

    Orton, Philip M.; McGillis, Wade R.; Zappa, Christopher J.

    2010-07-01

    The sea breeze is often a dominant meteorological feature at the coastline, but little is known about its estuarine impacts. Measurements at an anchored catamaran and meteorological stations along the Hudson River and New York Bay estuarine system are used to illustrate some basic characteristics and impacts of the feature. The sea breeze propagates inland, arriving in phase with peak solar forcing at seaward stations, but several hours later at up-estuary stations. Passage of the sea breeze front raises the water-to-air CO2 flux by 1-2 orders of magnitude, and drives turbulence comparable to spring tide levels in the upper meter of the water column, where most primary productivity occurs in this highly turbid system. Modeling and observational studies often use remotely-measured winds to compute air-water fluxes (e.g., momentum, CO2), and this leads to a factor of two flux error on sea breeze days during the study.

  20. Sensitivity of Air-sea Exchange In A Regional Scale Coupled Ice/ocean/atmosphere Model

    NASA Astrophysics Data System (ADS)

    Schrum, C.; Hübner, U.; Jacob, D.; Podzun, R.

    The sub-systems ice, ocean and atmosphere are coupled on the global as well as the regional scale. However, regional coupled modeling is only in the beginning, full cou- pled models which are able to describe the interaction on the regional scale and the feedback mechanism are rare at the moment. For the North Sea and the Baltic Sea such a coupled model has been developed and exemplary integrated over a full seasonal cy- cle. By comparison of different regionalization studies the impact of the regional at- mospheric modeling and coupling on the air sea fluxes have been investigated. It was shown that the regionalization as well as the coupling show strong influence on the air/sea fluxes and thus on the oceanic conditions. Further problems in regional mod- eling like the description of storm track variability and its influence on the regional ocean model were identified.

  1. High-resolution simulations of heavy precipitation events: role of the Adriatic SST and air-sea interactions

    NASA Astrophysics Data System (ADS)

    Davolio, Silvio; Stocchi, Paolo

    2016-04-01

    Strong Bora and Sirocco winds over the Adriatic Sea favour intense air-sea interactions and are often associated with heavy rainfall that affects the mountainous areas surrounding the basin. A convection-permitting model (MOLOCH) has been implemented at high resolution (2 km) in order to analyse several precipitation events over northern Italy, occurred during different seasons of the year and presenting different rainfall characteristics (stratiform, convective, orographic), and to possibly identify the relevant physical mechanisms involved. With the aim of assessing the impact of the sea surface temperature (SST) and surface fluxes on the intensity and location of the rainfall, sensitivity experiments have been performed taking into account the possible variability of SST analysis for model initialization. The model has been validated and specific diagnostic tools have been developed and applied to evaluate the vertically integrated moisture fluxes feeding the precipitating system or to compute a water balance in the atmosphere over the sea. The results show that the Adriatic Sea plays a role in determining the boundary layer characteristics through exchange of heat and moisture thus modifying the low-level flow dynamics and its interaction with the orography. This in turn impacts on the rainfall. Although the results vary among the analysed events, the precise definition of the SST and its evolution can be relevant for accurate precipitation forecasting.

  2. Survival of high latitude fringing corals in extreme temperatures: Red Sea oceanography

    NASA Astrophysics Data System (ADS)

    Moustafa, M. Z.; Moustafa, M. S.; Moustafa, Z. D.; Moustafa, S. E.

    2014-04-01

    This multi-year study set out to establish a comprehensive knowledgebase for a fringing coral reef in the Gulf of Suez, while also investigating the link between coral reef survivability and the extreme environmental conditions present in the region. The Gulf of Suez is a narrow branch of the northern Red Sea for which all forms of environmental and scientific data are severely lacking. Monitoring oceanographic and meteorological data provides evidence of both seasonal variability and interannual variability in this region, and may reveal correlations between reef health and prevailing climate conditions. Specifically, this research sought to document the environmental conditions under which Zaki's Reef, a small fringing coral reef (29.5°N and 32.4°E) that lies at the northernmost limit of tropical reefs worldwide, is able to survive, in order to determine how extreme the conditions are. Results of observed seawater temperature revealed that coral species at Zaki's Reef regularly experience 2-4 °C and 10-15 °C daily and seasonal temperature variations, respectively. Seawater temperature monthly means reached a minimum of 14 °C in February and a maximum of 33 °C in August. Monthly mean sea surface temperature climatology obtained from satellite measurements was comparable to observed seawater temperatures, while annual air and seawater temperature means were identical at 22 °C. Observed seawater temperatures exceeded established coral bleaching thresholds for extended periods of time, suggesting that coral species at this location may have developed a mechanism to cope with such extreme temperatures. Further scrutiny of these species and the mechanisms by which they are able to thrive is recommended.

  3. Obtaining the correct sea surface temperature: bias correction of regional climate model data for the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Macias, Diego; Garcia-Gorriz, Elisa; Dosio, Alessandro; Stips, Adolf; Keuler, Klaus

    2016-02-01

    Here, the COSMO Climate Limited-area Modelling (CCLM) regional climate model (RCM) is used as external forcing for a Mediterranean basin-scale ocean model based on the general estuarine transport model (GETM). CCLM is forced by different global climate models (GCMs) (MPI and EcEarth) and by the ERA-interim (ERAin) reanalysis. Sea surface temperatures (SST) simulated by the different runs of the ocean model are compared with satellite measurements. As a substantial cold bias in simulated SST is found, a simple bias-correction methodology is applied to the RCM atmospheric variables, namely (1) air temperature (which is usually underestimated for the region by RCMs runs), (2) cloud cover (typically overestimated) and (3) wind intensity (as zonal wind intensity is usually overestimated). The performed analysis identifies wind velocity as the most important variable to correct in order to satisfactorily obtain Mediterranean SST. For many of the RCM realizations significant improvement in the simulated SST are only achieved when wind intensity values were bias-corrected towards observed values. Air temperature and cloud cover had a more marginal importance in reducing the SST bias observed in RCM-forced runs of the ocean model. By comparing the ERAin-driven run and the GCMs driven runs, our analyses suggest that the main source of observed bias is related with the GCMs being used as lateral boundary condition for the RCM realizations. However, a relative simple bias-correction methodology is sufficient to reduce a large part of the induced bias in SST and to improve the vertical water stratification characteristics within the Mediterranean basin that will allow to analyze current and future biogeochemical conditions of the studied basin.

  4. Western Pacific Air-Sea Interaction Study (W-PASS), Introduction and Highlights (Invited)

    NASA Astrophysics Data System (ADS)

    Tsuda, A.

    2010-12-01

    Western Pacific Air-Sea Interaction Study (W-PASS), Introduction and Highlights Atsushi Tsuda Atmosphere and Ocean Research Institute, The University of Tokyo In the western Pacific (WESTPAC) region, dust originating from Asian and Australian arid regions to the North and South Pacific, biomass burning emissions from the Southeast Asia to sub-tropical Pacific, and other anthropogenic substances are transported regionally and globally to affect cloud and rainfall patterns, air quality, and radiative budgets downwind. Deposition of these compounds into the Asian marginal seas and onto the Pacific Ocean influence surface primary productivity and species composition. In the WESTPAC region, subarctic, subtropical oceans and marginal seas are located relatively narrow latitudinal range and these areas are influenced by the dust and anthropogenic inputs. Moreover, anthropogenic emission areas are located between the arid region and the oceans. The W-PASS (Western Pacific Air-Sea interaction Study) project has been funded for 5 years as a part of SOLAS-Japan activity in the summer of 2006. We aim to resolve air-sea interaction through field observation studies mainly using research vessels and island observatories over the western Pacific. We have carried out 5 cruises to the western North Pacific focusing on air-sea interactions. Also, an intensive marine atmospheric observation including direct atmospheric deposition measurement was accomplished by a dozen W-PASS research groups at the NIES Atmospheric and Aerosol Monitoring Station of Cape Hedo in the northernmost tip of the Okinawa main Island facing the East China Sea in the spring 2008. A few weak Kosa (dust) events, anthropogenic air outflows, typical local air and occupation of marine background air were identified during the campaign period. The W-PASS has four research groups mainly focusing on VOC emissions, air-sea gas exchange processes, biogeochemical responses to dust depositions and its modeling. We also

  5. The effect of water temperature on air entrainment, bubble plumes, and surface foam in a laboratory breaking-wave analog

    NASA Astrophysics Data System (ADS)

    Callaghan, A. H.; Stokes, M. D.; Deane, G. B.

    2014-11-01

    Air-entraining breaking waves form oceanic whitecaps and play a key role in climate regulation through air-sea bubble-mediated gas transfer, and sea spray aerosol production. The effect of varying sea surface temperature on air entrainment, subsurface bubble plume dynamics, and surface foam evolution intrinsic to oceanic whitecaps has not been well studied. By using a breaking wave analog in the laboratory over a range of water temperatures (Tw = 5°C to Tw = 30°C) and different source waters, we have examined changes in air entrainment, subsurface bubble plumes, and surface foam evolution over the course of a breaking event. For filtered seawater, air entrainment was estimated to increase by 6% between Tw = 6°C and Tw = 30°C, driven by increases of about 43% in the measured surface roughness of the plunging water sheet. After active air entrainment, the rate of loss of air through bubble degassing was more rapid at colder water temperatures within the first 0.5 s of plume evolution. Thereafter, the trend reversed and bubbles degassed more quickly in warmer water. The largest observed temperature-dependent differences in subsurface bubble distributions occurred at radii greater than about 700 μm. Temperature-dependent trends observed in the subsurface bubble plume were mirrored in the temporal evolution of the surface whitecap foam area demonstrating the intrinsic link between surface whitecap foam and the subsurface bubble plume. Differences in foam and plume characteristics due to different water sources were greater than the temperature dependencies for the filtered seawater examined.

  6. Estimation of Sea Surface Temperature (SST) Using Marine Seismic Data

    NASA Astrophysics Data System (ADS)

    Sinha, Satish Kumar; Dewangan, Pawan; Sain, Kalachand

    2016-04-01

    Not much attention is given to direct wave arrivals in marine seismic data that are acquired for petroleum exploration and prospecting. These direct arrivals are usually muted out in routine seismic data processing. In the present study, we process these direct arrivals to accurately estimate soundspeed in near-surface seawater and invert for sea surface temperature. The established empirical equation describing the relationships among temperature, salinity, pressure and soundspeed is used for the inversion. We also discuss processing techniques, such as first-break picking and cross-correlation for the estimation of soundspeed, that are well known among petroleum-industry geophysicists. The accuracy of the methods is directly linked to the data quality and signal processing. The novelty in our approach is in the data conditioning, which consists essentially of spectral balancing based on a wavelet transform that compensates for spherical spreading and increases the signal-to-noise ( S/ N) ratio. The 2D seismic data used in this paper are from the offshore Krishna-Godavari Basin east of India. We observe a significantly higher soundspeed of 1545 m/s for near-surface water than the commonly used value of ~1500 m/s. The estimated temperature (from velocity) is about 30 °C. Interestingly, the estimated temperature matches well with the temperature recorded in the CTD profile acquired in the study area during the month of May, the month corresponding to the acquisition of seismic data. Furthermore, the estimated temperatures during different times of data acquisition correlate well with the expected diurnal variation in temperature.

  7. MP3 - A Meteorology and Physical Properties Package to explore Air:Sea interaction on Titan

    NASA Astrophysics Data System (ADS)

    Lorenz, R. D.

    2012-04-01

    The exchange of mass, heat and momentum at the air:sea interface are profound influences on our environment. Titan presents us with an opportunity to study these processes in a novel physical context. The MP3 instrument, under development for the proposed Discovery mission TiME (Titan Mare Explorer) is an integrated suite of small, simple sensors that combines the a traditional meteorology package with liquid physical properties and depth-sounding. In TiME's 6-Titan-day (96-day) nominal mission, MP3 will have an extended measurement opportunity in one of the most evocative environments in the solar system. The mission and instrument benefit from APL's expertise and experience in marine as well as space systems. The topside meteorology sensors (METH, WIND, PRES, TEMP) will yield the first long-duration in-situ data to constrain Global Circulation Models. The sea sensors (TEMP, TURB, DIEL, SOSO) allow high cadence bulk composition measurements to detect heterogeneities as the TiME capsule drifts across Ligeia, while a depth sounder (SONR) will measure the bottom profile. The combination of these sensors (and vehicle dynamics, ACCL) will characterize air:sea exchange. In addition to surface data, a measurement subset (ACCL, PRES, METH, TEMP) is made during descent to characterize the structure of the polar troposphere and marine boundary layer. A single electronics box inside the vehicle performs supervising and data handling functions and is connected to the sensors on the exterior via a wire and fiber optic harness. ACCL: MEMS accelerometers and angular rate sensors measure the vehicle motion during descent and on the surface, to recover wave amplitude and period and to correct wind measurements for vehicle motion. TEMP: Precision sensors are installed at several locations above and below the 'waterline' to measure air and sea temperatures. Installation of topside sensors at several locations ensures that at least one is on the upwind side of the vehicle. PRES: The

  8. A pheromone outweighs temperature in influencing migration of sea lamprey

    USGS Publications Warehouse

    Brant, Cory O.; Li, Ke; Johnson, Nicholas S.; Li, Weiming

    2015-01-01

    Organisms continuously acquire and process information from surrounding cues. While some cues complement one another in delivering more reliable information, others may provide conflicting information. How organisms extract and use reliable information from a multitude of cues is largely unknown. We examined movement decisions of sea lampreys (Petromyzon marinus L.) exposed to a conspecific and an environmental cue during pre-spawning migration. Specifically, we predicted that the mature male-released sex pheromone 3-keto petromyzonol sulfate (3kPZS) will outweigh the locomotor inhibiting effects of cold stream temperature (less than 15°C). Using large-scale stream bioassays, we found that 3kPZS elicits an increase (more than 40%) in upstream movement of pre-spawning lampreys when the water temperatures were below 15°C. Both warming temperatures and conspecific cues increase upstream movement when the water temperature rose above 15°C. These patterns define an interaction between abiotic and conspecific cues in modulating animal decision-making, providing an example of the hierarchy of contradictory information.

  9. On the relationship between sea surface temperatures, circulation parameters and temperatures over west coast of India.

    PubMed

    Revadekar, J V; Varikoden, Hamza; Murumkar, P K; Ahmed, S A

    2016-05-01

    The oceans and the atmosphere are tightly linked and they together form the most dynamic component of the climate system. Topography and proximity to the surrounding seas of the region determine the temperature of the area. West Coast (WC) of India is a high elevated region surrounded by large oceanic area, therefore, an attempt is made in this study to examine the trends and variability in temperature over WC in relation to oceanic phenomena. Temperature over the WC shows considerable year-to-year variation with anomalous cool years in recent warm epoch. Therefore, sea surface temperature (SST) and associated winds have been analyzed to understand possible mechanism behind the variation in temperatures over the WC. During the winter, north-easterlies prevail over the WC which blows from land to ocean. Variations in SSTs alter the strength of these winds to cause anomalies in temperature over the WC. Indian Ocean Dipole (IOD) appears to have a dominant role in climate of the WC, whereas SSTs over the equatorial Pacific do not show any impact on temperatures over the WC. Study indicates that the strengthening of north-easterlies due to negative phase of Indian Ocean Dipole causes cooling over the WC of India. PMID:26874773

  10. Small-scale features of temperature and salinity surface fields in the Coral Sea

    NASA Astrophysics Data System (ADS)

    Maes, Christophe; Dewitte, Boris; Sudre, Joël.; Garçon, Véronique; Varillon, David

    2013-10-01

    The small-scale features in sea surface temperature and salinity fields (SST and SSS) of the Coral Sea are examined using high horizontal spatial and short-term temporal in situ measurements. These features are extracted from thermosalinographs (TSGs) gathered onboard commercial and research vessels and at one long-term fixed station. The analyses are performed along the vessel tracks and the structures of small-scale features are extracted by high-pass spatial filtering the original TSG data. For SSS, it is shown that the features at the scale of mesoscale eddies (˜100 km) vary from about -1.1 to +0.6 psu in the Coral Sea region. Processes sustaining such range include rainfall events, stirring by mesoscale eddies, and the latitudinal displacement of the sharp front associated with the edge of the Western Pacific Warm Pool at the seasonal time scales. The TSG data have revealed the presence of a sharp front (0.4-0.6 psu) between the subtropical and equatorial waters instead of a smooth gradient in the standard SSS climatologies. Within the context of recent remotely sensed observations of salinity, this could represent an important limitation for the validation and calibration of satellite products. In addition to these spatial considerations, temporal variations at one long-term station near Vanuatu show that the coupled air-sea responses to intraseasonal tropical variability, such as the Madden-Julian Oscillation, may have a signature in both SST and SSS fields. However, this response is found to be complex and not necessarily in phase. In the Coral Sea region, our results suggest that MJO-induced variability on SST and SSS exhibit little coherency at the seasonal time scales.

  11. The EUSTACE project: combining different components of the observing system to deliver global, daily information on surface air temperature

    NASA Astrophysics Data System (ADS)

    Rayner, Nick

    2016-04-01

    Day-to-day variations in surface air temperature affect society in many ways and are fundamental information for many climate services; however, daily surface air temperature measurements are not available everywhere. A global daily analysis cannot be achieved with measurements made in situ alone, so incorporation of satellite retrievals is needed. To achieve this, we must develop an understanding of the relationships between traditional surface air temperature measurements and retrievals of surface skin temperature from satellite measurements, i.e. Land Surface Temperature, Ice Surface Temperature, Sea Surface Temperature and Lake Surface Water Temperature. Here we reflect on our experience so far within the Horizon 2020 project EUSTACE of using satellite skin temperature retrievals to help us to produce a fully-global daily analysis (or ensemble of analyses) of surface air temperature on the centennial scale, integrating different ground-based and satellite-borne data types and developing new statistical models of how surface air temperature varies in a connected way from place to place. We will present plans and progress along this road in the EUSTACE project (2015-June 2018): - providing new, consistent, multi-component estimation of uncertainty in surface skin temperature retrievals from satellites; - identifying inhomogeneities in daily surface air temperature measurement series from weather stations and correcting for these over Europe; - estimating surface air temperature over all surfaces of Earth from surface skin temperature retrievals; - using new statistical techniques to provide information on higher spatial and temporal scales than currently available, making optimum use of information in data-rich eras. Information will also be given on how interested users can become involved.

  12. Influence of temperature, oxygen and salinity on the metabolism of the European sea bass

    NASA Astrophysics Data System (ADS)

    Claireaux, G.; Lagardère, J.-P.

    1999-09-01

    Standard (SMR) and routine (RMR) metabolic rates of groups (4 to 5 individuals) of European sea bass ( Dicentrarchus labrax) were measured at combinations of the following factors: temperature (10, 15, 20 and 25°C), oxygenation level (air saturation to 1.5 mg dm -3) and salinity (30, 20, 10 and 5‰). The influence of these environmental conditions on fish metabolic demand was then analysed through ANOVA. At 10, 15, 20 and 25°C, standard metabolic rates were 36, 65, 89, and 91 mg O 2 kg -1 h -1, respectively, while routine oxygen consumptions covered most of the metabolic range accessible. Osmoregulatory costs are linked to metabolic activity through ventilation. This relationship was highlighted by the observed interaction between environmental salinity and temperature. We were, however, unable to detect interactions between salinity and routine metabolic rate, or between salinity and oxygenation level. In order to delineate more precisely the restrictions imposed by water oxygenation on fish metabolic performance we determined the limiting oxygen concentration curves at each experimental temperature. We followed up by modelling the bass active metabolic rate (AMR) and metabolic scope (MS) as functions of both ambient temperature and oxygenation. These mathematical models allowed the characterisation of the controlling and limiting effects of water temperature and oxygen content on the metabolic capacity of the species. Thus, AMR at 10, 15 and 20°C were estimated at 65, 160 and 360 mg O 2 kg -1 h -1, respectively. However, at higher temperature (25°C) AMR dropped slightly (to 340 mg O 2 kg -1 h -1). Bass MS increased by a factor of 9 between 10 and 20°C, but diminished at higher temperatures. The present study contributes to our current understanding of the influences of environmental factors on the metabolism of sea bass and provides a bioenergetic basis for a study of how environmental constraints govern the spatial and temporal distribution pattern of this

  13. Heat tolerance of higher plants cenosis to damaging air temperatures

    NASA Astrophysics Data System (ADS)

    Ushakova, Sofya; Shklavtsova, Ekaterina

    Designing sustained biological-technical life support systems (BTLSS) including higher plants as a part of a photosynthesizing unit, it is important to foresee the multi species cenosis reaction on either stress-factors. Air temperature changing in BTLSS (because of failure of a thermoregulation system) up to the values leading to irreversible damages of photosynthetic processes is one of those factors. However, it is possible to increase, within the certain limits, the plant cenosis tolerance to the unfavorable temperatures’ effect due to the choice of the higher plants possessing resistance both to elevated and to lowered air temperatures. Besides, the plants heat tolerance can be increased when subjecting them during their growing to the hardening off temperatures’ effect. Thus, we have come to the conclusion that it is possible to increase heat tolerance of multi species cenosis under the damaging effect of air temperature of 45 (°) СC.

  14. Innovative coal gasification system with high temperature air

    SciTech Connect

    Yoshikawa, K.; Katsushima, H.; Kasahara, M.; Hasegawa, T.; Tanaka, R.; Ootsuka, T.

    1997-12-31

    This paper proposes innovative coal gasification power generation systems where coal is gasified with high temperature air of about 1300K produced by gasified coal fuel gas. The main features of these systems are high thermal efficiency, low NO{sub x} emission, compact desulfurization and dust removal equipment and high efficiency molten slag removal with a very compact gasifier. Recent experimental results on the pebble bed coal gasifier appropriate for high temperature air coal gasification are reported, where 97.7% of coal ash is successfully caught in the pebble bed and extracted without clogging. A new concept of high temperature air preheating system is proposed which is characterized by its high reliability and low cost.

  15. Experimental sea slicks: Their practical applications and utilization for basic studies of air-sea interactions

    NASA Astrophysics Data System (ADS)

    Hühnerfuss, Heinrich; Garrett, W. D.

    1981-01-01

    Practical applications of organic surface films added to the sea surface date back to ancient times. Aristotle, Plutarch, and Pliny the Elder describe the seaman's practice of calming waves in a storm by pouring oil onto the sea [Scott, 1977]. It was also noted that divers released oil beneath the water surface so that it could rise and spread over the sea surface, thereby suppressing the irritating flicker associated with the passage of light through a rippled surface. From a scientific point of view, Benjamin Franklin was the first to perform experiments with oils on natural waters. His experiment with a `teaspoonful of oil' on Clapham pond in 1773 inspired many investigators to consider sea surface phenomena or to conduct experiments with oil films. This early research has been reviewed by Giles [1969], Giles and Forrester [1970], and Scott [1977]. Franklin's studies with experimental slicks can be regarded as the beginning of surface film chemistry. His speculations on the wave damping influence of oil induced him to perform the first qualitative experiment with artificial sea slicks at Portsmouth (England) in October of 1773. Although the sea was calmed and very few white caps appeared in the oil-covered area, the swell continued through the oiled area to Franklin's great disappointment.

  16. The role of subsurface soil temperature feedbacks in summer surface air temperature variability over East Asia

    NASA Astrophysics Data System (ADS)

    Zhang, J.

    2012-12-01

    Soil temperature, an important component of land surface, can influence the climate through its effects on surface energy and water budgets and resulted changes in regional atmospheric circulation. However, the effects of soil temperature on climate variations have been less discussed. This study investigates the role of subsurface soil temperature feedbacks in influencing summer surface air temperature variability over East Asia by means of regional climate model (RCM) simulations. For this aim, two long-term simulations with and without subsurface soil temperature feedbacks are performed with the Weather Research and Forecasting (WRF) model. From our investigation, it is evident that subsurface soil temperature feedbacks make a dominant contribution to amplifying summer surface air temperature variability over the arid/semi-arid regions. Further analysis reveals that subsurface soil temperature exhibits an asymmetric effect on summer daytime and nighttime surface air temperature variability, with a stronger effect on daily minimum temperature variability than that of daily maximum temperature variability. This study provides the first RCM-based demonstration that subsurface soil temperature feedbacks play an important role in influencing climate variability over East Asia, such as summer surface air temperature. In the meanwhile, the model bias should be recognized. The results achieved by this study thus need to be further confirmed in a multi-model framework to eliminate the model dependence.

  17. Passive radiative cooling below ambient air temperature under direct sunlight.

    PubMed

    Raman, Aaswath P; Anoma, Marc Abou; Zhu, Linxiao; Rephaeli, Eden; Fan, Shanhui

    2014-11-27

    Cooling is a significant end-use of energy globally and a major driver of peak electricity demand. Air conditioning, for example, accounts for nearly fifteen per cent of the primary energy used by buildings in the United States. A passive cooling strategy that cools without any electricity input could therefore have a significant impact on global energy consumption. To achieve cooling one needs to be able to reach and maintain a temperature below that of the ambient air. At night, passive cooling below ambient air temperature has been demonstrated using a technique known as radiative cooling, in which a device exposed to the sky is used to radiate heat to outer space through a transparency window in the atmosphere between 8 and 13 micrometres. Peak cooling demand, however, occurs during the daytime. Daytime radiative cooling to a temperature below ambient of a surface under direct sunlight has not been achieved because sky access during the day results in heating of the radiative cooler by the Sun. Here, we experimentally demonstrate radiative cooling to nearly 5 degrees Celsius below the ambient air temperature under direct sunlight. Using a thermal photonic approach, we introduce an integrated photonic solar reflector and thermal emitter consisting of seven layers of HfO2 and SiO2 that reflects 97 per cent of incident sunlight while emitting strongly and selectively in the atmospheric transparency window. When exposed to direct sunlight exceeding 850 watts per square metre on a rooftop, the photonic radiative cooler cools to 4.9 degrees Celsius below ambient air temperature, and has a cooling power of 40.1 watts per square metre at ambient air temperature. These results demonstrate that a tailored, photonic approach can fundamentally enable new technological possibilities for energy efficiency. Further, the cold darkness of the Universe can be used as a renewable thermodynamic resource, even during the hottest hours of the day. PMID:25428501

  18. Satellite-Derived Sea Surface Temperature: Workshop 3

    NASA Technical Reports Server (NTRS)

    1985-01-01

    This is the third of a series of three workshops, sponsored by the National Aeronautics and Space Administration, to investigate the state of the art in global sea surface temperature measurements from space. Three workshops were necessary to process and analyze sufficient data from which to draw conclusions on the accuracy and reliability of the satellite measurements. In this workshop, the final two (out of a total of four) months of satellite and in situ data chosen for study were processed and evaluated. Results from the AVHRR, HIRS, SMMR, and VAS sensors, in comparison with in situ data from ships, XBTs, and buoys, confirmed satellite rms accuracies in the 0.5 to 1.0 C range, but with variable biases. These accuracies may degrade under adverse conditions for specific sensors. A variety of color maps, plots, and statistical tables are provided for detailed study of the individual sensor SST measurements.

  19. Tropical cyclone rainfall area controlled by relative sea surface temperature

    PubMed Central

    Lin, Yanluan; Zhao, Ming; Zhang, Minghua

    2015-01-01

    Tropical cyclone rainfall rates have been projected to increase in a warmer climate. The area coverage of tropical cyclones influences their impact on human lives, yet little is known about how tropical cyclone rainfall area will change in the future. Here, using satellite data and global atmospheric model simulations, we show that tropical cyclone rainfall area is controlled primarily by its environmental sea surface temperature (SST) relative to the tropical mean SST (that is, the relative SST), while rainfall rate increases with increasing absolute SST. Our result is consistent with previous numerical simulations that indicated tight relationships between tropical cyclone size and mid-tropospheric relative humidity. Global statistics of tropical cyclone rainfall area are not expected to change markedly under a warmer climate provided that SST change is relatively uniform, implying that increases in total rainfall will be confined to similar size domains with higher rainfall rates. PMID:25761457

  20. Emission Controls Using Different Temperatures of Combustion Air

    PubMed Central

    Holubčík, Michal; Papučík, Štefan

    2014-01-01

    The effort of many manufacturers of heat sources is to achieve the maximum efficiency of energy transformation chemically bound in the fuel to heat. Therefore, it is necessary to streamline the combustion process and minimize the formation of emission during combustion. The paper presents an analysis of the combustion air temperature to the heat performance and emission parameters of burning biomass. In the second part of the paper the impact of different dendromass on formation of emissions in small heat source is evaluated. The measured results show that the regulation of the temperature of the combustion air has an effect on concentration of emissions from the combustion of biomass. PMID:24971376

  1. Proxy data constraints on Cretaceous sea surface temperature evolution

    NASA Astrophysics Data System (ADS)

    O'Brien, Charlotte L.; Robinson, Stuart A.; O'Connor, Lauren K.; Pancost, Richard D.

    2015-04-01

    It is well established that greenhouse conditions prevailed during the Cretaceous. However, constraining the exact nature of the greenhouse gas forcing, climatic warming and climate sensitivity remains an ongoing topic of research. Proxy temperature data provide valuable observational constraints on Cretaceous climate. In particular, much of our understanding of Cretaceous climate warmth comes from marine temperature proxy data reconstructions derived using planktic foraminiferal oxygen isotope (δ18O) palaeothermometry and, more recently, the TEX86 proxy, based on the distribution of marine isoprenoidal glycerol dialkyl glycerol tetraether lipids (GDGTs). Both of these proxies provide estimates of sea surface temperature (SST), however each technique is subject to a number of proxy-specific caveats. For example, δ18O values in planktic foraminifer may be compromised by preservation and/or diagenetic alteration, while the TEX86 proxy has undergone several temperature calibration re-evaluations and the exact mechanism that relates GDGT production to SST is not fully understood. Here we synthesise and reinterpret available TEX86- and δ18O-SST proxy data for the entire Cretaceous. For the TEX86 data, where possible we re-evaluate the fractional abundance of all individual GDGTs. By utilising fractional GDGT abundances we are also able to compute methane indices and branched and isoprenoid tetraether (BIT) indices, as well as apply both the TEX86H and TEX86L temperature calibrations. For each of the two SST proxy techniques, TEX86 and δ18O, we apply consistent temperature calibrations and place all data on a common timescale. Our new data-based SST synthesis allows us to examine long term temperature trends in the Cretaceous, including latitudinal temperature gradient variations, and evaluate global versus regional temperature patterns. Through considering both TEX86 and planktic foraminiferal δ18O data we critically compare the application of these two techniques

  2. Variability of Winter Air Temperature in Mid-Latitude Europe

    NASA Technical Reports Server (NTRS)

    Otterman, J.; Ardizzone, J.; Atlas, R.; Bungato, D.; Cierniewski, J.; Jusem, J. C.; Przybylak, R.; Schubert, S.; Starr, D.; Walczewski, J.

    2002-01-01

    The aim of this paper is to report extreme winter/early-spring air temperature (hereinafter temperature) anomalies in mid-latitude Europe, and to discuss the underlying forcing to these interannual fluctuations. Warm advection from the North Atlantic in late winter controls the surface-air temperature, as indicated by the substantial correlation between the speed of the surface southwesterlies over the eastern North Atlantic (quantified by a specific Index Ina) and the 2-meter level air temperatures (hereinafter Ts) over Europe, 45-60 deg N, in winter. In mid-March and subsequently, the correlation drops drastically (quite often it is negative). This change in the relationship between Ts and Ina marks a transition in the control of the surface-air temperature: absorption of insolation replaces the warm advection as the dominant control. This forcing by maritime-air advection in winter was demonstrated in a previous publication, and is re-examined here in conjunction with extreme fluctuations of temperatures in Europe. We analyze here the interannual variability at its extreme by comparing warm-winter/early-spring of 1989/90 with the opposite scenario in 1995/96. For these two December-to-March periods the differences in the monthly mean temperature in Warsaw and Torun, Poland, range above 10 C. Short-term (shorter than a month) fluctuations of the temperature are likewise very strong. We conduct pentad-by-pentad analysis of the surface-maximum air temperature (hereinafter Tmax), in a selected location, examining the dependence on Ina. The increased cloudiness and higher amounts of total precipitable water, corollary effects to the warm low-level advection. in the 1989/90 winter, enhance the positive temperature anomalies. The analysis of the ocean surface winds is based on the Special Sensor Microwave/Imager (SSM/I) dataset; ascent rates, and over land wind data are from the European Centre for Medium-Range Weather Forecasts (ECMWF); maps of 2-m temperature, cloud

  3. Seasonal sea surface temperature anomaly prediction for coastal ecosystems

    NASA Astrophysics Data System (ADS)

    Stock, Charles A.; Pegion, Kathy; Vecchi, Gabriel A.; Alexander, Michael A.; Tommasi, Desiree; Bond, Nicholas A.; Fratantoni, Paula S.; Gudgel, Richard G.; Kristiansen, Trond; O'Brien, Todd D.; Xue, Yan; Yang, Xiasong

    2015-09-01

    Sea surface temperature (SST) anomalies are often both leading indicators and important drivers of marine resource fluctuations. Assessment of the skill of SST anomaly forecasts within coastal ecosystems accounting for the majority of global fish yields, however, has been minimal. This reflects coarse global forecast system resolution and past emphasis on the predictability of ocean basin-scale SST variations. This paper assesses monthly to inter-annual SST anomaly predictions in coastal "Large Marine Ecosystems" (LMEs). We begin with an analysis of 7 well-observed LMEs adjacent to the United States and then examine how mechanisms responsible for prediction skill in these systems are reflected in predictions for LMEs globally. Historical SST anomaly estimates from the 1/4° daily Optimal Interpolation Sea Surface Temperature reanalysis (OISST.v2) were first found to be highly consistent with in-situ measurements for 6 of the 7 U.S. LMEs. Thirty years of retrospective forecasts from climate forecast systems developed at NOAA's Geophysical Fluid Dynamics Laboratory (CM2.5-FLOR) and the National Center for Environmental Prediction (CFSv2) were then assessed against OISST.v2. Forecast skill varied widely by LME, initialization month, and lead but there were many cases of high skill that also exceeded that of a persistence forecast, some at leads greater than 6 months. Mechanisms underlying skill above persistence included accurate simulation of (a) seasonal transitions between less predictable locally generated and more predictable basin-scale SST variability; (b) seasonal transitions between different basin-scale influences; (c) propagation of SST anomalies across seasons through sea ice; and (d) re-emergence of previous anomalies upon the breakdown of summer stratification. Globally, significant skill above persistence across many tropical systems arises via mechanisms (a) and (b). Combinations of all four mechanisms contribute to less prevalent but nonetheless

  4. Sea ice pCO2 dynamics and air-ice CO2 fluxes during the Sea Ice Mass Balance in the Antarctic (SIMBA) experiment - Bellingshausen Sea, Antarctica

    NASA Astrophysics Data System (ADS)

    Geilfus, N.-X.; Tison, J.-L.; Ackley, S. F.; Galley, R. J.; Rysgaard, S.; Miller, L. A.; Delille, B.

    2014-12-01

    Temporal evolution of pCO2 profiles in sea ice in the Bellingshausen Sea, Antarctica, in October 2007 shows physical and thermodynamic processes controls the CO2 system in the ice. During the survey, cyclical warming and cooling strongly influenced the physical, chemical, and thermodynamic properties of the ice cover. Two sampling sites with contrasting characteristics of ice and snow thickness were sampled: one had little snow accumulation (from 8 to 25 cm) and larger temperature and salinity variations than the second site, where the snow cover was up to 38 cm thick and therefore better insulated the underlying sea ice. We show that each cooling/warming event was associated with an increase/decrease in the brine salinity, total alkalinity (TA), total dissolved inorganic carbon (TCO2), and in situ brine and bulk ice CO2 partial pressures (pCO2). Thicker snow covers reduced the amplitude of these changes: snow cover influences the sea ice carbonate system by modulating the temperature and therefore the salinity of the sea ice cover. Results indicate that pCO2 was undersaturated with respect to the atmosphere both in the in situ bulk ice (from 10 to 193 μatm) and brine (from 65 to 293 μatm), causing the sea ice to act as a sink for atmospheric CO2 (up to 2.9 mmol m-2 d-1), despite supersaturation of the underlying seawater (up to 462 μatm).

  5. Regulation of CO2 Air Sea Fluxes by Sediments in the North Sea

    NASA Astrophysics Data System (ADS)

    Burt, William; Thomas, Helmuth; Hagens, Mathilde; Brenner, Heiko; Pätsch, Johannes; Clargo, Nicola; Salt, Lesley

    2016-04-01

    A multi-tracer approach is applied to assess the impact of boundary fluxes (e.g. benthic input from sediments or lateral inputs from the coastline) on the acid-base buffering capacity, and overall biogeochemistry, of the North Sea. Analyses of both basin-wide observations in the North Sea and transects through tidal basins at the North-Frisian coastline, reveal that surface distributions of the δ13C signature of dissolved inorganic carbon (DIC) are predominantly controlled by a balance between biological production and respiration. In particular, variability in metabolic DIC throughout stations in the well-mixed southern North Sea indicates the presence of an external carbon source, which is traced to the European continental coastline using naturally-occurring radium isotopes (224Ra and 228Ra). 228Ra is also shown to be a highly effective tracer of North Sea total alkalinity (AT) compared to the more conventional use of salinity. Coastal inputs of metabolic DIC and AT are calculated on a basin-wide scale, and ratios of these inputs suggest denitrification as a primary metabolic pathway for their formation. The AT input paralleling the metabolic DIC release prevents a significant decline in pH as compared to aerobic (i.e. unbuffered) release of metabolic DIC. Finally, long-term pH trends mimic those of riverine nitrate loading, highlighting the importance of coastal AT production via denitrification in regulating pH in the southern North Sea.

  6. Regionalized global budget of the CO2 exchange at the air-water interface in continental shelf seas

    NASA Astrophysics Data System (ADS)

    Laruelle, Goulven G.; Lauerwald, Ronny; Pfeil, Benjamin; Regnier, Pierre

    2014-11-01

    Over the past decade, estimates of the atmospheric CO2 uptake by continental shelf seas were constrained within the 0.18-0.45 Pg C yr-1 range. However, most of those estimates are based on extrapolations from limited data sets of local flux measurements (n < 100). Here we propose to derive the CO2 air-sea exchange of the shelf seas by extracting 3 · 106 direct surface ocean CO2 measurements from the global database SOCAT (Surface Ocean CO2 Atlas), atmospheric CO2 values from GlobalVIEW and calculating gas transfer rates using readily available global temperature, salinity, and wind speed fields. We then aggregate our results using a global segmentation of the shelf in 45 units and 152 subunits to establish a consistent regionalized CO2 exchange budget at the global scale. Within each unit, the data density determines the spatial and temporal resolutions at which the air-sea CO2 fluxes are calculated and range from a 0.5° resolution in the best surveyed regions to a whole unit resolution in areas where data coverage is limited. Our approach also accounts, for the first time, for the partial sea ice cover of polar shelves. Our new regionalized global CO2 sink estimate of 0.19 ± 0.05 Pg C yr-1 falls in the low end of previous estimates. Reported to an ice-free surface area of 22 · 106 km2, this value yields a flux density of 0.7 mol C m-2 yr-1, ~40% more intense than that of the open ocean. Our results also highlight the significant contribution of Arctic shelves to this global CO2 uptake (0.07 Pg C yr-1).

  7. Pulsed positive streamer discharges in air at high temperatures

    NASA Astrophysics Data System (ADS)

    Ono, Ryo; Kamakura, Taku

    2016-08-01

    Atmospheric-pressure air pulsed positive streamer discharges are generated in a 13 mm point-plane gap in the temperature range of 293 K–1136 K, and the effect of temperature on the streamer discharges is studied. When the temperature is increased, the product of applied voltage and temperature VT proportional to the reduced electric field can be used as a primary parameter that determines some discharge parameters regardless of temperature. For a given VT, the transferred charge per pulse, streamer diameter, product of discharge energy and temperature, and length of secondary streamer are almost constant regardless of T, whereas the streamer velocity decreases with increasing T and the decay rate of the discharge current is proportional to 1/T. The N2(C) emission intensity is approximately determined by the discharge energy independent of T. These results are useful to predict the streamer discharge and its reactive species production when the ambient temperature is increased.

  8. Impacts of South East Biomass Burning on local air quality in South China Sea

    NASA Astrophysics Data System (ADS)

    Wai-man Yeung, Irene; Fat Lam, Yun; Eniolu Morakinyo, Tobi

    2016-04-01

    Biomass burning is a significant source of carbon monoxide and particulate matter, which is not only contribute to the local air pollution, but also regional air pollution. This study investigated the impacts of biomass burning emissions from Southeast Asia (SEA) as well as its contribution to the local air pollution in East and South China Sea, including Hong Kong and Taiwan. Three years (2012 - 2014) of the Hybrid Single Particle Lagrangian-Integrated Trajectory (HYSPLIT) with particles dispersion analyses using NCEP (Final) Operational Global Analysis data (FNL) data (2012 - 2014) were analyzed to track down all possible long-range transport from SEA with a sinking motion that worsened the surface air quality (tropospheric downwash from the free troposphere). The major sources of SEA biomass burning emissions were first identified using high fire emissions from the Global Fire Emission Database (GFED), followed by the HYSPLIT backward trajectory dispersion modeling analysis. The analyses were compared with the local observation data from Tai Mo Shan (1,000 msl) and Tap Mun (60 msl) in Hong Kong, as well as the data from Lulin mountain (2,600 msl) in Taiwan, to assess the possible impacts of SEA biomass burning on local air quality. The correlation between long-range transport events from the particles dispersion results and locally observed air quality data indicated that the background concentrations of ozone, PM2.5 and PM10 at the surface stations were enhanced by 12 μg/m3, 4 μg/m3 and 7 μg/m3, respectively, while the long-range transport contributed to enhancements of 4 μg/m3, 4 μg/m3 and 8 μg/m3 for O3, PM2.5 and PM10, respectively at the lower free atmosphere.

  9. Effects of air flow directions on composting process temperature profile

    SciTech Connect

    Kulcu, Recep; Yaldiz, Osman

    2008-07-01

    In this study, chicken manure mixed with carnation wastes was composted by using three different air flow directions: R1-sucking (downward), R2-blowing (upward) and R3-mixed. The aim was to find out the most appropriate air flow direction type for composting to provide more homogenous temperature distribution in the reactors. The efficiency of each aeration method was evaluated by monitoring the evolution of parameters such as temperature, moisture content, CO{sub 2} and O{sub 2} ratio in the material and dry material losses. Aeration of the reactors was managed by radial fans. The results showed that R3 resulted in a more homogenous temperature distribution and high dry material loss throughout the composting process. The most heterogeneous temperature distribution and the lowest dry material loss were obtained in R2.

  10. Temperature gradients and clear-air turbulence probabilities

    NASA Technical Reports Server (NTRS)

    Bender, M. A.; Panofsky, H. A.; Peslen, C. A.

    1976-01-01

    In order to forecast clear-air turbulence (CAT) in jet aircraft flights, a study was conducted in which the data from a special-purpose instrument aboard a Boeing 747 jet airliner were compared with satellite-derived radiance gradients, conventional temperature gradients from analyzed maps, and temperature gradients obtained from a total air temperature sensor on the plane. The advantage of making use of satellite-derived data is that they are available worldwide without the need for radiosonde observations, which are scarce in many parts of the world. Major conclusions are that CAT probabilities are significantly higher over mountains than flat terrain, and that satellite radiance gradients appear to discriminate between CAT and no CAT better than conventional temperature gradients over flat lands, whereas the reverse is true over mountains, the differences between the two techniques being not large over mountains.

  11. The Effects of Air Pollution and Temperature on COPD.

    PubMed

    Hansel, Nadia N; McCormack, Meredith C; Kim, Victor

    2016-06-01

    Chronic Obstructive Pulmonary Disease (COPD) affects 12-16 million people in the United States and is the third-leading cause of death. In developed countries, smoking is the greatest risk factor for the development of COPD, but other exposures also contribute to the development and progression of the disease. Several studies suggest, though are not definitive, that outdoor air pollution exposure is linked to the prevalence and incidence of COPD. Among individuals with COPD, outdoor air pollutants are associated with loss of lung function and increased respiratory symptoms. In addition, outdoor air pollutants are also associated with COPD exacerbations and mortality. There is much less evidence for the impact of indoor air on COPD, especially in developed countries in residences without biomass exposure. The limited existing data suggests that indoor particulate matter and nitrogen dioxide concentrations are linked to increased respiratory symptoms among patients with COPD. In addition, with the projected increases in temperature and extreme weather events in the context of climate change there has been increased attention to the effects of heat exposure. Extremes of temperature-both heat and cold-have been associated with increased respiratory morbidity in COPD. Some studies also suggest that temperature may modify the effect of pollution exposure and though results are not conclusive, understanding factors that may modify susceptibility to air pollution in patients with COPD is of utmost importance. PMID:26683097

  12. Experimental and theoretical analysis results for high temperature air combustion

    SciTech Connect

    Tanigawa, Tadashi; Morita, Mitsunobu

    1998-07-01

    With Japan's preparation of its Action program to prevent global warming in 1990 and the holding of the United National Conference on Environment and Development (the Earth Summit) in 1992 as a backdrop, reflecting the global effort to protect the environment, a high performance industrial furnace development project was launched in 1993 by the New Energy and Industrial Technology Development Organization (NEDO). This project focuses on the development of a combustion technology which uses air that is preheated to extremely high temperatures (above 1,000 C), heretofore considered impossible. Not only can this technology reduce carbon dioxide emission, thought to cause the greenhouse effect, by over 30%, but it can also reduce nitrogen oxide emission by nearly half. This new technology makes use of the recently-developed high-cycle regenerative heat exchanger, for preheating the furnace air supply. This exchanger preheats air to above 1,000 C, much higher than for conventional furnaces, and then this air is injected with fuel. R and D data have shown that CO{sub 2} and NO{sub x} emissions can be reduced markedly. However, the theoretical analysis is yet to be made, thereby hampering efforts to have this advanced technology become widely adopted. This project accumulated new data related to uniform temperature distribution, high energy heat transfer and low NO{sub x} as common characteristics of high temperature air combustion.

  13. The organic sea surface microlayer in the upwelling region off Peru and implications for air-sea exchange processes

    NASA Astrophysics Data System (ADS)

    Engel, A.; Galgani, L.

    2015-07-01

    The sea surface microlayer (SML) is at the very surface of the ocean, linking the hydrosphere with the atmosphere, and central to a range of global biogeochemical and climate-related processes. The presence and enrichment of organic compounds in the SML have been suggested to influence air-sea gas exchange processes as well as the emission of primary organic aerosols. Among these organic compounds, primarily of plankton origin, are dissolved exopolymers, specifically polysaccharides and proteins, and gel particles, such as Transparent Exopolymer Particles (TEP) and Coomassie Stainable Particles (CSP). These organic substances often accumulate in the surface ocean when plankton productivity is high. Here, we report results obtained in December 2012 during the SOPRAN Meteor 91 cruise to the highly productive, coastal upwelling regime off Peru. Samples were collected from the SML and from ~ 20 cm below, and were analyzed for polysaccharidic and proteinaceous compounds, gel particles, total and dissolved organic carbon, bacterial and phytoplankton abundance. Our study provides insight to the physical and biological control of organic matter enrichment in the SML, and discusses the potential role of organic matter in the SML for air-sea exchange processes.

  14. Flame Speeds of Methane-Air, Propane-Air, and Ethylene-Air Mixtures at Low Initial Temperatures

    NASA Technical Reports Server (NTRS)

    Dugger, Gordon L; Heimel, Sheldon

    1952-01-01

    Flame speeds were determined for methane-air, propane-air, and ethylene-air mixtures at -73 C and for methane-air mixtures at -132 C. The data extend the curves of maximum flame speed against initial mixture temperature previously established for the range from room temperature to 344 C. Empirical equations for maximum flame speed u(cm/ sec) as a function of initial mixture temperature T(sub O) were determined to be as follows: for methane, for T(sub O) from 141 to 615 K, u = 8 + 0.000160 T(sub O)(exp 2.11); for propane, for T(sub O) from 200 to 616 K, u = 10 + 0.000342 T(sub O)(exp 2.00); for ethylene, for T(sub O) from 200 to 617 K, u = 10 + 0.00259 T(sub O)(exp 1.74). Relative flame speeds at low initial temperatures were predicted within approximately 20 percent by either the thermal theory as presented by Semenov or by the diffusion theory of Tanford and Pease. The same order was found previously for high initial temperatures. The low-temperature data were also found to extend the linear correlations between maximum flame speed and calculated equilibrium active-radical concentrations, which were established by the previously reported high-temperature data.

  15. Sea surface temperature anomalies in the South China Sea during mature phase of ENSO

    NASA Astrophysics Data System (ADS)

    Qiu, Fuwen; Pan, Aijun; Zhang, Shanwu; Cha, Jing; Sun, Haowei

    2016-05-01

    Based on the 18-year (1993-2010) National Centers for Environmental Prediction optimum interpolation sea surface temperature (SST) and simple ocean data assimilation datasets, this study investigated the patterns of the SST anomalies (SSTAs) that occurred in the South China Sea (SCS) during the mature phase of the El Niño/Southern Oscillation. The most dominant characteristic was that of the outof-phase variation between southwestern and northeastern parts of the SCS, which was influenced primarily by the net surface heat flux and by horizontal thermal advection. The negative SSTA in the northeastern SCS was caused mainly by the loss of heat to the atmosphere and because of the cold-water advection from the western Pacific through the Luzon Strait during El Niño episodes. Conversely, it was found that the anomalous large-scale atmospheric circulation and weakened western boundary current during El Niño episodes led to the development of the positive SSTA in the southwestern SCS.

  16. Drier Air, Lower Temperatures, and Triggering of Paroxysmal Atrial Fibrillation

    PubMed Central

    Nguyen, Jennifer L.; Link, Mark S.; Luttmann-Gibson, Heike; Laden, Francine; Schwartz, Joel; Wessler, Benjamin S.; Mittleman, Murray A.; Gold, Diane R.; Dockery, Douglas W.

    2015-01-01

    Background The few previous studies on the onset of paroxysmal atrial fibrillation and meteorologic conditions have focused on outdoor temperature and hospital admissions, but hospital admissions are a crude indicator of atrial fibrillation incidence, and studies have found other weather measures in addition to temperature to be associated with cardiovascular outcomes. Methods Two hundred patients with dual chamber implantable cardioverter-defibrillators were enrolled and followed prospectively from 2006 to 2010 for new onset episodes of atrial fibrillation. The date and time of arrhythmia episodes documented by the implanted cardioverter-defibrillators were linked to meteorologic data and examined using a case-crossover analysis. We evaluated associations with outdoor temperature, apparent temperature, air pressure, and three measures of humidity (relative humidity, dew point, and absolute humidity). Results Of the 200 enrolled patients, 49 patients experienced 328 atrial fibrillation episodes lasting ≥30 seconds. Lower temperatures in the prior 48 hours were positively associated with atrial fibrillation. Lower absolute humidity (ie, drier air) had the strongest and most consistent association: each 0.5 g/m3 decrease in the prior 24 hours increased the odds of atrial fibrillation by 4% (95% confidence interval [CI]: 0%, 7%) and by 5% (95% CI: 2%, 8%) for exposure in the prior 2 hours. Results were similar for dew point but slightly weaker. Conclusions Recent exposure to drier air and lower temperatures were associated with the onset of atrial fibrillation among patients with known cardiac disease, supporting the hypothesis that meteorologic conditions trigger acute cardiovascular episodes. PMID:25756220

  17. Sedation and anesthesia of hatchling leatherback sea turtles (Dermochelys coriacea) for auditory evoked potential measurement in air and in water.

    PubMed

    Harms, Craig A; Piniak, Wendy E D; Eckert, Scott A; Stringer, Elizabeth M

    2014-03-01

    Sedation or anesthesia of hatchling leatherback sea turtles was employed to acquire auditory evoked potential (AEP) measurements in air and in water to assess their hearing sensitivity in relation to potential consequences from anthropogenic noise. To reduce artifacts in AEP collection caused by muscle movement, hatchlings were sedated with midazolam 2 or 3 mg/kg i.v. for in-air (n = 7) or in-water (n = 11) AEP measurements; hatchlings (n = 5) were anesthetized with ketamine 6 mg/kg and dexmedetomidine 30 microg/kg i.v. reversed with atipamezole 300 microg/kg, half i.m. and half i.v. for in-air AEP measurements. Midazolam-sedated turtles were also physically restrained with a light elastic wrap. For in-water AEP measurements, sedated turtles were brought to the surface every 45-60 sec, or whenever they showed intention signs for breathing, and not submerged again until they took a breath. Postprocedure temperature-corrected venous blood pH, pCO2, pO2, and HCO3- did not differ among groups, although for the midazolam-sedated in-water group, pCO2 trended lower, and in the ketamine-dexmedetomidine anesthetized group there was one turtle considered clinically acidotic (temperature-corrected pH = 7.117). Venous blood lactate was greater for hatchlings recently emerged from the nest than for turtles sedated with midazolam in air, with the other two groups falling intermediate between, but not differing significantly from the high and low lactate groups. Disruptive movements were less frequent with anesthesia than with sedation in the in-air group. Both sedation with midazolam and anesthesia with ketamine-dexmedetomidine were successful for allowing AEP measurements in hatchling leatherback sea turtles. Sedation allowed the turtle to protect its airway voluntarily while limiting flipper movement. Midazolam or ketamine-dexmedetomidine (and reversal with atipamezole) would be useful for other procedures requiring minor or major restraint in leatherback sea turtle hatchlings

  18. Updating sea spray aerosol emissions in the Community Multiscale Air Quality (CMAQ) model

    EPA Science Inventory

    Sea spray aerosols (SSA) impact the particle mass concentration and gas-particle partitioning in coastal environments, with implications for human and ecosystem health. In this study, the Community Multiscale Air Quality (CMAQ) model is updated to enhance fine mode SSA emissions,...

  19. Variational iteration method for solving sea-air oscillator of the ENSO model

    NASA Astrophysics Data System (ADS)

    Noor, N. F. M.

    2015-10-01

    A class of sea-air oscillator of the El Nino-Southern Oscillation (ENSO) mechanism is considered. Variational iteration method (VIM) is applied to generate approximate solution to the system. Numerical VIM solutions obtained are then compared with results from the analytical solution and the Runge-Kutta-Fehlberg method of fourth-fifth order (RKF45).

  20. Modeling daily average stream temperature from air temperature and watershed area

    NASA Astrophysics Data System (ADS)

    Butler, N. L.; Hunt, J. R.

    2012-12-01

    Habitat restoration efforts within watersheds require spatial and temporal estimates of water temperature for aquatic species especially species that migrate within watersheds at different life stages. Monitoring programs are not able to fully sample all aquatic environments within watersheds under the extreme conditions that determine long-term habitat viability. Under these circumstances a combination of selective monitoring and modeling are required for predicting future geospatial and temporal conditions. This study describes a model that is broadly applicable to different watersheds while using readily available regional air temperature data. Daily water temperature data from thirty-eight gauges with drainage areas from 2 km2 to 2000 km2 in the Sonoma Valley, Napa Valley, and Russian River Valley in California were used to develop, calibrate, and test a stream temperature model. Air temperature data from seven NOAA gauges provided the daily maximum and minimum air temperatures. The model was developed and calibrated using five years of data from the Sonoma Valley at ten water temperature gauges and a NOAA air temperature gauge. The daily average stream temperatures within this watershed were bounded by the preceding maximum and minimum air temperatures with smaller upstream watersheds being more dependent on the minimum air temperature than maximum air temperature. The model assumed a linear dependence on maximum and minimum air temperature with a weighting factor dependent on upstream area determined by error minimization using observed data. Fitted minimum air temperature weighting factors were consistent over all five years of data for each gauge, and they ranged from 0.75 for upstream drainage areas less than 2 km2 to 0.45 for upstream drainage areas greater than 100 km2. For the calibration data sets within the Sonoma Valley, the average error between the model estimated daily water temperature and the observed water temperature data ranged from 0.7

  1. The Effect of Ocean Currents on Sea Surface Temperature Anomalies

    NASA Technical Reports Server (NTRS)

    Stammer, Detlef; Leeuwenburgh, Olwijn

    2000-01-01

    We investigate regional and global-scale correlations between observed anomalies in sea surface temperature and height. A strong agreement between the two fields is found over a broad range of latitudes for different ocean basins. Both time-longitude plots and wavenumber-frequency spectra suggest an advective forcing of SST anomalies by a first-mode baroclinic wave field on spatial scales down to 400 km and time scales as short as 1 month. Even though the magnitude of the mean background temperature gradient is determining for the effectiveness of the forcing, there is no obvious seasonality that can be detected in the amplitudes of SST anomalies. Instead, individual wave signatures in the SST can in some cases be followed over periods of two years. The phase relationship between SST and SSH anomalies is dependent upon frequency and wavenumber and displays a clear decrease of the phase lag toward higher latitudes where the two fields come into phase at low frequencies. Estimates of the damping coefficient are larger than generally obtained for a purely atmospheric feedback. From a global frequency spectrum a damping time scale of 2-3 month was found. Regionally results are very variable and range from 1 month near strong currents to 10 month at low latitudes and in the sub-polar North Atlantic. Strong agreement is found between the first global EOF modes of 10 day averaged and spatially smoothed SST and SSH grids. The accompanying time series display low frequency oscillations in both fields.

  2. Advances in Fast Response Acoustically Derived Air Temperature Measurements

    NASA Astrophysics Data System (ADS)

    Bogoev, Ivan; Jacobsen, Larry; Horst, Thomas; Conrad, Benjamin

    2016-04-01

    Fast-response accurate air-temperature measurements are required when estimating turbulent fluxes of heat, water and carbon dioxide by open-path eddy-covariance technique. In comparison with contact thermometers like thermocouples, ultra-sonic thermometers do not suffer from solar radiation loading, water vapor condensation and evaporative cooling effects. Consequently they have the potential to provide more accurate true air temperature measurements. The absolute accuracy of the ultrasonic thermometer is limited by the following parameters: the distance between the transducer pairs, transducer delays associated with the electrical-acoustic signal conversion that vary with temperature, components of the wind vector that are normal to the ultrasonic paths, and humidity. The distance between the transducer pairs is commonly obtained by coordinate measuring machine. Improved accuracy demonstrated in this study results from increased stiffness in the anemometer head to better maintain the ultrasonic path-length distances. To further improve accuracy and account for changes in transducer delays and distance as a function of temperature, these parameters are characterized in a zero-wind chamber over the entire operating temperature range. When the sonic anemometer is combined with a co-located fast-response water vapor analyzer, like in the IRGASON instrument, speed of sound can be compensated for humidity effects on a point-by-point basis resulting in a true fast-response air temperature measurement. Laboratory test results show that when the above steps are implemented in the calibration of the ultrasonic thermometer air-temperature accuracy better than ±0.5 degrees Celsius can be achieved over the entire operating range. The approach is also validated in a field inter-comparison with an aspirated thermistor probe mounted in a radiation shield.

  3. Forecasting decadal changes in sea surface temperatures and coral bleaching within a Caribbean coral reef

    NASA Astrophysics Data System (ADS)

    Li, Angang; Reidenbach, Matthew A.

    2014-09-01

    Elevated sea surface temperature (SST) caused by global warming is one of the major threats to coral reefs. While increased SST has been shown to negatively affect the health of coral reefs by increasing rates of coral bleaching, how changes to atmospheric heating impact SST distributions, modified by local flow environments, has been less understood. This study aimed to simulate future water flow patterns and water surface heating in response to increased air temperature within a coral reef system in Bocas del Toro, Panama, located within the Caribbean Sea. Water flow and SST were modeled using the Delft3D-FLOWcomputer simulation package. Locally measured physical parameters, including bathymetry, astronomic tidal forcing, and coral habitat distribution were input into the model and water flow, and SST was simulated over a four-month period under present day, as well as projected warming scenarios in 2020s, 2050s, and 2080s. Changes in SST, and hence the thermal stress to corals, were quantified by degree heating weeks. Results showed that present-day reported bleaching sites were consistent with localized regions of continuous high SST. Regions with highest SST were located within shallow coastal sites adjacent to the mainland or within the interior of the bay, and characterized by low currents with high water retention times. Under projected increases in SSTs, shallow reef areas in low flow regions were found to be hot spots for future bleaching.

  4. Long-Range Correlations of Global Sea Surface Temperature.

    PubMed

    Jiang, Lei; Zhao, Xia; Wang, Lu

    2016-01-01

    Scaling behaviors of the global monthly sea surface temperature (SST) derived from 1870-2009 average monthly data sets of Hadley Centre Sea Ice and SST (HadISST) are investigated employing detrended fluctuation analysis (DFA). The global SST fluctuations are found to be strong positively long-range correlated at all pertinent time-intervals. The value of scaling exponent is larger in the tropics than those in the intermediate latitudes of the northern and southern hemispheres. DFA leads to the scaling exponent α = 0.87 over the globe (60°S~60°N), northern hemisphere (0°N~60°N), and southern hemisphere (0°S~60°S), α = 0.84 over the intermediate latitude of southern hemisphere (30°S~60°S), α = 0.81 over the intermediate latitude of northern hemisphere (30°N~60°N) and α = 0.90 over the tropics 30°S~30°N [fluctuation F(s) ~ sα], which the fluctuations of monthly SST anomaly display long-term correlated behaviors. Furthermore, the larger the standard deviation is, the smaller long-range correlations (LRCs) of SST in the corresponding regions, especially in three distinct upwelling areas. After the standard deviation is taken into account, an index χ = α * σ is introduced to obtain the spatial distributions of χ. There exists an obvious change of global SST in central east and northern Pacific and the northwest Atlantic. This may be as a clue on predictability of climate and ocean variabilities. PMID:27100397

  5. Long-Range Correlations of Global Sea Surface Temperature

    PubMed Central

    Jiang, Lei; Zhao, Xia; Wang, Lu

    2016-01-01

    Scaling behaviors of the global monthly sea surface temperature (SST) derived from 1870–2009 average monthly data sets of Hadley Centre Sea Ice and SST (HadISST) are investigated employing detrended fluctuation analysis (DFA). The global SST fluctuations are found to be strong positively long-range correlated at all pertinent time-intervals. The value of scaling exponent is larger in the tropics than those in the intermediate latitudes of the northern and southern hemispheres. DFA leads to the scaling exponent α = 0.87 over the globe (60°S~60°N), northern hemisphere (0°N~60°N), and southern hemisphere (0°S~60°S), α = 0.84 over the intermediate latitude of southern hemisphere (30°S~60°S), α = 0.81 over the intermediate latitude of northern hemisphere (30°N~60°N) and α = 0.90 over the tropics 30°S~30°N [fluctuation F(s) ~ sα], which the fluctuations of monthly SST anomaly display long-term correlated behaviors. Furthermore, the larger the standard deviation is, the smaller long-range correlations (LRCs) of SST in the corresponding regions, especially in three distinct upwelling areas. After the standard deviation is taken into account, an index χ = α * σ is introduced to obtain the spatial distributions of χ. There exists an obvious change of global SST in central east and northern Pacific and the northwest Atlantic. This may be as a clue on predictability of climate and ocean variabilities. PMID:27100397

  6. A case study of sea breeze blocking regulated by sea surface temperature along the English south coast

    NASA Astrophysics Data System (ADS)

    Sweeney, J. K.; Chagnon, J. M.; Gray, S. L.

    2013-09-01

    The sensitivity of sea breeze structure to sea surface temperature (SST) and coastal orography is investigated in convection-permitting Met Office Unified Model simulations of a case study along the south coast of England. Changes in SST of 1 K are shown to significantly modify the structure of the sea breeze. On the day of the case study the sea breeze was partially blocked by coastal orography, particularly within Lyme Bay. The extent to which the flow is blocked depends strongly on the static stability of the marine boundary layer. In experiments with colder SST, the marine boundary layer is more stable, and the degree of blocking is more pronounced. The implications of prescribing fixed SST from climatology in numerical weather prediction model forecasts of the sea breeze are discussed.

  7. Heterogeneous oxidation of a phosphocholine on synthetic sea salt by ozone at room temperature.

    PubMed

    Dilbeck, Christopher W; Finlayson-Pitts, Barbara J

    2013-02-14

    The ozonolysis of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) adsorbed on salt mixtures as models for sea-salt particles was studied in real time using diffuse reflection infrared Fourier transform spectrometry (DRIFTS) at room temperature with and without added water vapor. The salt substrates were a mixture of MgCl(2)·6H(2)O with NaCl or a commercially available synthetic sea salt. Ozone concentrations ranged from (0.25 to 3.9) × 10(13) molecules cm(-3) (0.1-1.6 ppm). The major products identified by FTIR and confirmed using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry were the secondary ozonide (SOZ) and a phospholipid aldehyde and carboxylic acid formed by scission of the double bond. The reaction probabilities for the two substrates were similar, γ = (6-7) × 10(-7), with an estimated overall uncertainty of a factor of two. The presence of water vapor decreased the yield of SOZ relative to the products formed by C[double bond, length as m-dash]C scission, but also increased the availability of the double bond for reaction, particularly on the less hygroscopic commercial sea-salt substrate. Thus, water not only affects the mechanisms and products, but also the structure of the phospholipid on the salt in a manner that affects its reactivity. The results of these studies suggest that the reactivity and products of oxidation of unsaturated phospholipids on sea-salt particles in air will be very sensitive to the nature and phase of the substrate, the amount of water present, and whether there is phase separation between the organics and the inorganic salt mixture. PMID:23258195

  8. The mass and speed dependence of meteor air plasma temperatures

    NASA Technical Reports Server (NTRS)

    Jenniskens, Peter; Laux, Christophe O.; Wilson, Michael A.; Schaller, Emily L.

    2004-01-01

    The speed and mass dependence of meteor air plasma temperatures is perhaps the most important data needed to understand how small meteoroids chemically change the ambient atmosphere in their path and enrich the ablated meteoric organic matter with oxygen. Such chemistry can play an important role in creating prebiotic compounds. The excitation conditions in various air plasma emissions were measured from high-resolution optical spectra of Leonid storm meteors during NASA's Leonid Multi-Instrument Aircraft Campaign. This was the first time a sufficient number and range of temperature measurements were obtained to search for meteoroid mass and speed dependencies. We found slight increases in temperature with decreasing altitude, but otherwise nearly constant values for meteoroids with speeds between 35 and 72 km/s and masses between 10(-5) g and 1 g. We conclude that faster and more massive meteoroids produce a larger emission volume, but not a higher air plasma temperature. We speculate that the meteoric plasma may be in multiphase equilibrium with the ambient atmosphere, which could mean lower plasma temperatures in a CO(2)-rich early Earth atmosphere.

  9. CARS Temperature and Species Measurements For Air Vehicle Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Danehy, Paul M.; Gord, James R.; Grisch, Frederic; Klimenko, Dmitry; Clauss, Walter

    2005-01-01

    The coherent anti-Stokes Raman spectroscopy (CARS) method has recently been used in the United States and Europe to probe several different types of propulsion systems for air vehicles. At NASA Langley Research Center in the United States, CARS has been used to simultaneously measure temperature and the mole fractions of N2, O2 and H2 in a supersonic combustor, representative of a scramjet engine. At Wright- Patterson Air Force Base in the United States, CARS has been used to simultaneously measure temperature and mole fractions of N2, O2 and CO2, in the exhaust stream of a liquid-fueled, gas-turbine combustor. At ONERA in France and the DLR in Germany researchers have used CARS to measure temperature and species concentrations in cryogenic LOX-H2 rocket combustion chambers. The primary aim of these measurements has been to provide detailed flowfield information for computational fluid dynamics (CFD) code validation.

  10. Microwave temperature profiler for clear air turbulence prediction

    NASA Technical Reports Server (NTRS)

    Gary, Bruce L. (Inventor)

    1992-01-01

    A method is disclosed for determining Richardson Number, Ri, or its reciprocal, RRi, for clear air prediction using measured potential temperature and determining the vertical gradient of potential temperature, d(theta)/dz. Wind vector from the aircraft instrumentation versus potential temperature, dW/D(theta), is determined and multiplies by d(theta)/dz to obtain dW/dz. Richardson number or its reciprocal is then determined from the relationship Ri = K(d theta)/dz divided by (dW/dz squared) for use in detecting a trend toward a threshold value for the purpose of predicting clear air turbulence. Other equations for this basic relationship are disclosed together with the combination of other atmospheric observables using multiple regression techniques.

  11. Fiber optic distributed temperature sensing for the determination of air temperature

    NASA Astrophysics Data System (ADS)

    de Jong, S. A. P.; Slingerland, J. D.; van de Giesen, N. C.

    2015-01-01

    This paper describes a method to correct for the effect of solar radiation in atmospheric distributed temperature sensing (DTS) applications. By using two cables with different diameters, one can determine what temperature a zero diameter cable would have. Such a virtual cable would not be affected by solar heating and would take on the temperature of the surrounding air. With two unshielded cable pairs, one black pair and one white pair, good results were obtained given the general consensus that shielding is needed to avoid radiation errors (WMO, 2010). The correlations between standard air temperature measurements and air temperatures derived from both cables of colors had a high correlation coefficient (r2=0.99) and a RMSE of 0.38 °C, compared to a RMSE of 2.40 °C for a 3.0 mm uncorrected black cable. A thin white cable measured temperatures that were close to air temperature measured with a nearby shielded thermometer (RMSE of 0.61 °C). The temperatures were measured along horizontal cables with an eye to temperature measurements in urban areas, but the same method can be applied to any atmospheric DTS measurements, and for profile measurements along towers or with balloons and quadcopters.

  12. The Effects of Air Pollution and Temperature on COPD

    PubMed Central

    Hansel, Nadia N.; McCormack, Meredith C.; Kim, Victor

    2016-01-01

    Chronic Obstructive Pulmonary Disease (COPD) affects 12–16 million people in the United States and is the third-leading cause of death. In developed countries, smoking is the greatest risk factor for the development of COPD, but other exposures also contribute to the development and progression of the disease. Several studies suggest, though are not definitive, that outdoor air pollution exposure is linked to the prevalence and incidence of COPD. Among individuals with COPD, outdoor air pollutants are associated with loss of lung function and increased respiratory symptoms. In addition, outdoor air pollutants are also associated with COPD exacerbations and mortality. There is much less evidence for the impact of indoor air on COPD, especially in developed countries in residences without biomass exposure. The limited existing data suggests that indoor particulate matter and nitrogen dioxide concentrations are linked to increased respiratory symptoms among patients with COPD. In addition, with the projected increases in temperature and extreme weather events in the context of climate change there has been increased attention to the effects of heat exposure. Extremes of temperature—both heat and cold—have been associated with increased respiratory morbidity in COPD. Some studies also suggest that temperature may modify the effect of pollution exposure and though results are not conclusive, understanding factors that may modify susceptibility to air pollution in patients with COPD is of utmost importance. PMID:26683097

  13. Destruction of Iodocarbons in Surface Seawater - Implications for Sea-Air Flux Calculations and the Atmospheric Iodine Budget

    NASA Astrophysics Data System (ADS)

    Jones, C. E.; Dunk, R. M.; Hornsby, K. E.; McFiggans, G.; Carpenter, L. J.

    2007-12-01

    Although it is now widely accepted that CH3I is the major volatile organic source of iodine from the surface ocean to the atmosphere, CH3I emissions alone cannot balance the global iodine budget, which implies that there must be some additional source(s). Seawater and air measurements made during two cruises in the Atlantic Ocean during summer 2006 and spring 2007 suggest that other iodocarbons, in particular the dihaloalkanes CH2I2, CH2IBr and CH2ICl, may provide a combined global iodine atom source which is comparable to that of CH3I. However, deriving sea-to-air fluxes of these volatile gases is not straightforward. Established flux parameterizations are based on air and surface water concentrations, but seawater samples from ship campaigns are typically taken from at least 2-6 m depth (since there are technical difficulties associated with sampling closer to the surface). Given its relatively long lifetime in the oceans, sea-air fluxes of CH3I may be adequately approximated directly from concentrations measured a few metres below the surface, however for the dihalomethanes this is likely to give rise to considerable inaccuracies due to their short lifetimes with respect to photolysis in surface waters. Consequently, we have used a one-dimensional oceanic mixed layer model to constrain the extent of dihalomethane photodecay within the top few metres of the water column such that we can extrapolate surface seawater concentrations from sub-surface measurements, which in turn allows more accurate sea-air fluxes to be determined for these gases. A number of mono-iodinated alkanes were also detected in Atlantic seawater, including C2H5I and 1- C3H7I. Laboratory based studies have been carried out in order to parameterize the temperature- dependent chemical destruction of a number of mono-iodinated alkanes in saltwater, such that the oceanic lifetimes of these species may be predicted as a simple function of the surface seawater temperature. In light of these results

  14. Forecasting Fire Season Severity in South America Using Sea Surface Temperature Anomalies

    NASA Technical Reports Server (NTRS)

    Chen, Yang; Randerson, James T.; Morton, Douglas C.; DeFries, Ruth S.; Collatz, G. James; Kasibhatla, Prasad S.; Giglio, Louis; Jin, Yufang; Marlier, Miriam E.

    2011-01-01

    Fires in South America cause forest degradation and contribute to carbon emissions associated with land use change. We investigated the relationship between year-to-year changes in fire activity in South America and sea surface temperatures. We found that the Oceanic Ni o Index was correlated with interannual fire activity in the eastern Amazon, whereas the Atlantic Multidecadal Oscillation index was more closely linked with fires in the southern and southwestern Amazon. Combining these two climate indices, we developed an empirical model to forecast regional fire season severity with lead times of 3 to 5 months. Our approach may contribute to the development of an early warning system for anticipating the vulnerability of Amazon forests to fires, thus enabling more effective management with benefits for climate and air quality.

  15. Predicting Fire Season Severity in South America Using Sea Surface Temperature Anomalies

    NASA Technical Reports Server (NTRS)

    Chen, Yang; Randerson, James T.; Morton, Douglas C.; Jin, Yufang; DeFries, Ruth S.; Collatz, George J.; Kasibhatla, Prasad S.; Giglio, Louis; Jin, Yufang; Marlier, Miriam

    2011-01-01

    Fires in South America cause forest degradation and contribute to carbon emissions associated with land use change. Here we investigated the relationship between year-to-year changes in satellite-derived estimates of fire activity in South America and sea surface temperature (SST) anomalies. We found that the Oceanic Ni o Index (ONI) was correlated with interannual fire activity in the eastern Amazon whereas the Atlantic Multidecadal Oscillation (AMO) index was more closely linked with fires in the southern and southwestern Amazon. Combining these two climate indices, we developed an empirical model that predicted regional annual fire season severity (FSS) with 3-5 month lead times. Our approach provides the foundation for an early warning system for forecasting the vulnerability of Amazon forests to fires, thus enabling more effective management with benefits for mitigation of greenhouse gas and air pollutant emissions.

  16. Forecasting fire season severity in South America using sea surface temperature anomalies.

    PubMed

    Chen, Yang; Randerson, James T; Morton, Douglas C; DeFries, Ruth S; Collatz, G James; Kasibhatla, Prasad S; Giglio, Louis; Jin, Yufang; Marlier, Miriam E

    2011-11-11

    Fires in South America cause forest degradation and contribute to carbon emissions associated with land use change. We investigated the relationship between year-to-year changes in fire activity in South America and sea surface temperatures. We found that the Oceanic Niño Index was correlated with interannual fire activity in the eastern Amazon, whereas the Atlantic Multidecadal Oscillation index was more closely linked with fires in the southern and southwestern Amazon. Combining these two climate indices, we developed an empirical model to forecast regional fire season severity with lead times of 3 to 5 months. Our approach may contribute to the development of an early warning system for anticipating the vulnerability of Amazon forests to fires, thus enabling more effective management with benefits for climate and air quality. PMID:22076373

  17. Determination of temperature and pressure patterns associated to sea ice fields in Antarctica, with modern tools of pattern recognition

    NASA Astrophysics Data System (ADS)

    Orquera, F. J.; Torchio, M. A.; Barreira, S.

    2012-12-01

    Monthly sea ice anomalies derived from passive microwave satellite data for Antarctica spanning the period 1979-2010 are classified into 16 different patterns (6 for summer and autumn and 10 for winter and spring). Each of these patterns has an atmospheric temperature and pressure structure associated with it (i.e., a specific mode of climate variability). These results were obtained using principal component analysis (PCA) in T-Mode. Here we attempt to identify the sea ice pattern for 2011 without using the passive microwave data, and instead using what can be inferred from the temperature and pressure fields associated with the patterns. We approach this issue with a multilayer Perceptron (neuronal network) with supervised learning and a back-propagation algorithm. The Perceptron is the most common Artificial Neural Network topology dedicated to image pattern recognition. It was implemented through the use of temperature and pressure anomalies field images that were associated with a group of sea ice anomaly patterns. The variables analyzed included only composites of surface air temperature and pressure to simplify the density of input data and avoid a non-converging solution (monthly input data for the period 1979-2010). The results of this analysis can be used to identify the sea ice patterns without the need of a new PCA analysis of the sea ice data. The anticipated outcome of this study is to obtain an accurate prediction of sea ice and perform a forecast. The findings may be vital to a more accurate planning of future missions to coastal Antarctic bases.

  18. Air-sea interaction with SSM/I and altimeter

    NASA Technical Reports Server (NTRS)

    1985-01-01

    A number of important developments in satellite remote sensing techniques have occurred recently which offer the possibility of studying over vast areas of the ocean the temporally evolving energy exchange between the ocean and the atmosphere. Commencing in spring of 1985, passive and active microwave sensors that can provide valuable data for scientific utilization will start to become operational on Department of Defense (DOD) missions. The passive microwave radiometer can be used to estimate surface wind speed, total air column humidity, and rain rate. The active radar, or altimeter, senses surface gravity wave height and surface wind speed.

  19. Air pollution, temperature and pediatric influenza in Brisbane, Australia.

    PubMed

    Xu, Zhiwei; Hu, Wenbiao; Williams, Gail; Clements, Archie C A; Kan, Haidong; Tong, Shilu

    2013-09-01

    Previous studies have demonstrated the importance of weather variables in influencing the incidence of influenza. However, the role of air pollution is often ignored in identifying the environmental drivers of influenza. This research aims to examine the impacts of air pollutants and temperature on the incidence of pediatric influenza in Brisbane, Australia. Lab-confirmed daily data on influenza counts among children aged 0-14years in Brisbane from 2001 January 1st to 2008 December 31st were retrieved from Queensland Health. Daily data on maximum and minimum temperatures for the same period were supplied by the Australian Bureau of Meteorology. Winter was chosen as the main study season due to it having the highest pediatric influenza incidence. Four Poisson log-linear regression models, with daily pediatric seasonal influenza counts as the outcome, were used to examine the impacts of air pollutants (i.e., ozone (O3), particulate matter≤10μm (PM10) and nitrogen dioxide (NO2)) and temperature (using a moving average of ten days for these variables) on pediatric influenza. The results show that mean temperature (Relative risk (RR): 0.86; 95% Confidence Interval (CI): 0.82-0.89) was negatively associated with pediatric seasonal influenza in Brisbane, and high concentrations of O3 (RR: 1.28; 95% CI: 1.25-1.31) and PM10 (RR: 1.11; 95% CI: 1.10-1.13) were associated with more pediatric influenza cases. There was a significant interaction effect (RR: 0.94; 95% CI: 0.93-0.95) between PM10 and mean temperature on pediatric influenza. Adding the interaction term between mean temperature and PM10 substantially improved the model fit. This study provides evidence that PM10 needs to be taken into account when evaluating the temperature-influenza relationship. O3 was also an important predictor, independent of temperature. PMID:23911338

  20. The impact of rising sea temperature on innate immune parameters in the tropical subtidal sea urchin Lytechinus variegatus and the intertidal sea urchin Echinometra lucunter.

    PubMed

    Branco, Paola Cristina; Borges, João Carlos Shimada; Santos, Marinilce Fagundes; Jensch Junior, Bernard Ernesto; da Silva, José Roberto Machado Cunha

    2013-12-01

    Ocean temperatures are rising throughout the world, making it necessary to evaluate the impact of these temperature changes on sea urchins, which are well-known bioindicators. This study evaluated the effect of an increase in temperature on the immune response of the subtidal Lytechinus variegatus and the intertidal Echinometra lucunter sea urchins. Both species were exposed to 20 (control), 25 and 30 °C temperatures for 24 h, 2, 7 and 14 days. Counting of coelomocytes and assays on the phagocytic response, adhesion and spreading of coelomocytes were performed. Red and colorless sphere cells were considered biomarkers for heat stress. Moreover, a significant decrease in the phagocytic indices and a decrease in both cell adhesion and cell spreading were observed at 25 and 30 °C for L. variegatus. For E. lucunter, the only alteration observed was for the cell proportions. This report shows how different species of sea urchins respond immunologically to rising temperatures. PMID:24080411

  1. Impacts of air-sea exchange coefficients on snowfall events over the Korean Peninsula

    NASA Astrophysics Data System (ADS)

    Kang, Jung-Yoon; Kwon, Young Cheol

    2016-08-01

    Snowfall over the Korean Peninsula is mainly associated with air mass transformation by the fluxes across the air-sea interface during cold-air outbreaks over the warm Yellow Sea. The heat and momentum exchange coefficients in the surface flux parameterization are key parameters of flux calculations across the air-sea interface. This study investigates the effects of the air-sea exchange coefficients on the simulations of snowfall events over the Korean Peninsula using the Weather Research and Forecasting (WRF) model. Two snowfall cases are selected for this study. One is a heavy snowfall event that took place on January 4, 2010, and the other is a light snowfall event that occurred on December 23-24, 2011. Several sensitivity tests are carried out with increased and decreased heat and momentum exchange coefficients. The domain-averaged precipitation is increased (decreased) with increased (decreased) heat exchange coefficient because the increased (decreased) surface heat flux leads to more (less) moist conditions in the low level of the atmosphere. On the other hand, the domain-averaged precipitation is decreased (increased) with increased (decreased) momentum exchange coefficient because the increased (decreased) momentum coefficient causes reduction (increase) of wind speed and heat flux. The variation of precipitation in the heat exchange coefficient experiments is much larger than that in the momentum exchange coefficient experiments because the change of heat flux has a more direct impact on moisture flux and snowfall amount, while the change of momentum flux has a rather indirect impact via wind speed changes. The low-pressure system is intensified and moves toward North when the heat exchange coefficient is increased because warming and moistening of the lower atmosphere contributes to destabilize the air mass, resulting in the change of precipitation pattern over the Korean Peninsula in the heat exchange coefficient experiments.

  2. Requirements for high-temperature air-cooled central receivers

    SciTech Connect

    Wright, J.D.; Copeland, R.J.

    1983-12-01

    The design of solar thermal central receivers will be shaped by the end user's need for energy. This paper identifies the requirements for receivers supplying heat for industrial processes or electric power generation in the temperature range 540 to 1000/sup 0/C and evaluates the effects of the requirements on air-cooled central receivers. Potential IPH applications are identified as large baseload users that are located some distance from the receiver. In the electric power application, the receiver must supply heat to a pressurized gas power cycle. The difficulty in providing cost-effective thermal transport and thermal storage for air-cooled receivers is a critical problem.

  3. Can air temperature be used to project influences of climate change on stream temperature?

    USGS Publications Warehouse

    Arismendi, Ivan; Safeeq, Mohammad; Dunham, Jason B.; Johnson, Sherri L.

    2014-01-01

    Worldwide, lack of data on stream temperature has motivated the use of regression-based statistical models to predict stream temperatures based on more widely available data on air temperatures. Such models have been widely applied to project responses of stream temperatures under climate change, but the performance of these models has not been fully evaluated. To address this knowledge gap, we examined the performance of two widely used linear and nonlinear regression models that predict stream temperatures based on air temperatures. We evaluated model performance and temporal stability of model parameters in a suite of regulated and unregulated streams with 11–44 years of stream temperature data. Although such models may have validity when predicting stream temperatures within the span of time that corresponds to the data used to develop them, model predictions did not transfer well to other time periods. Validation of model predictions of most recent stream temperatures, based on air temperature–stream temperature relationships from previous time periods often showed poor performance when compared with observed stream temperatures. Overall, model predictions were less robust in regulated streams and they frequently failed in detecting the coldest and warmest temperatures within all sites. In many cases, the magnitude of errors in these predictions falls within a range that equals or exceeds the magnitude of future projections of climate-related changes in stream temperatures reported for the region we studied (between 0.5 and 3.0 °C by 2080). The limited ability of regression-based statistical models to accurately project stream temperatures over time likely stems from the fact that underlying processes at play, namely the heat budgets of air and water, are distinctive in each medium and vary among localities and through time.

  4. Sensitivity of Greenland Ice Sheet surface mass balance to perturbations in sea surface temperature and sea ice cover: a study with the regional climate model MAR

    NASA Astrophysics Data System (ADS)

    Noël, B.; Fettweis, X.; van de Berg, W. J.; van den Broeke, M. R.; Erpicum, M.

    2014-10-01

    During recent summers (2007-2012), several surface melt records were broken over the Greenland Ice Sheet (GrIS). The extreme summer melt resulted in part from a persistent negative phase of the North Atlantic Oscillation (NAO), favoring warmer atmospheric conditions than normal over the GrIS. Simultaneously, large anomalies in sea ice cover (SIC) and sea surface temperature (SST) were observed in the North Atlantic, suggesting a possible connection. To assess the direct impact of 2007-2012 SIC and SST anomalies on GrIS surface mass balance (SMB), a set of sensitivity experiments was carried out with the regional climate model MAR forced by ERA-Interim. These simulations suggest that perturbations in SST and SIC in the seas surrounding Greenland do not considerably impact GrIS SMB, as a result of the katabatic wind blocking effect. These offshore-directed winds prevent oceanic near-surface air, influenced by SIC and SST anomalies, from penetrating far inland. Therefore, the ice sheet SMB response is restricted to coastal regions, where katabatic winds cease. A topic for further investigation is how anomalies in SIC and SST might have indirectly affected the surface melt by changing the general circulation in the North Atlantic region, hence favoring more frequent warm air advection towards the GrIS.

  5. Variability of sea surface temperature in the Japan Sea and its relationship to the wind-curl field

    NASA Astrophysics Data System (ADS)

    Trusenkova, O. O.; Lobanov, V. B.; Kaplunenko, D. D.

    2008-08-01

    The variability of sea surface temperature (SST) in the Japan Sea is investigated using the complex EOF analysis of daily data produced at Tohoku University, Japan (New Generation SST; 2002-2006). The relationship with the wind field is investigated from the daily NCEP/NCAR reanalysis data with a 1° spatial resolution. Anomalies in the SST (SSTAs) are calculated by subtracting the basin-average annual variation estimated as a leading mode of temperature. The leading mode of an SSTA represents a adjustment to the annual mean variation, most significant in December in the zone of subtropical waters entering the sea through the Korean Strait and in the northwestern sea, over which a cyclonic wind curl develops in the cold period. The semiannual variability mode is identified, which is characterized by the largest temperature increase (decrease) in the western branch of the subarctic front (in the Tatar Strait), which lags by two months behind the semiannual changes in wind curl over the sea. An episodic SSTA movement is detected in the northern part of the sea, which moves from east to west along the western branch of the Tsushima Warm Current with a speed corresponding in magnitude to an advective scale.

  6. Can air temperatures be used to project influences of climate change on stream temperatures?

    NASA Astrophysics Data System (ADS)

    Arismendi, I.; Safeeq, M.; Dunham, J.; Johnson, S. L.

    2013-12-01

    The lack of available in situ stream temperature records at broad spatiotemporal scales have been recognized as a major limiting factor in the understanding of thermal behavior of stream and river systems. This has motivated the promotion of a wide variety of models that use surrogates for stream temperatures including a regression approach that uses air temperature as the predictor variable. We investigate the long-term performance of widely used linear and non-linear regression models between air and stream temperatures to project the latter in future climate scenarios. Specifically, we examine the temporal variability of the parameters that define each of these models in long-term stream and air temperature datasets representing relatively natural and highly human-influenced streams. We selected 25 sites with long-term records that monitored year-round daily measurements of stream temperature (daily mean) in the western United States (California, Oregon, Idaho, Washington, and Alaska). Surface air temperature data from each site was not available. Therefore, we calculated daily mean surface air temperature for each site in contiguous US from a 1/16-degree resolution gridded surface temperature data. Our findings highlight several limitations that are endemic to linear or nonlinear regressions that have been applied in many recent attempts to project future stream temperatures based on air temperature. Our results also show that applications over longer time periods, as well as extrapolation of model predictions to project future stream temperatures are unlikely to be reliable. Although we did not analyze a broad range of stream types at a continental or global extent, our analysis of stream temperatures within the set of streams considered herein was more than sufficient to illustrate a number of specific limitations associated with statistical projections of stream temperature based on air temperature. Radar plots of Nash-Sutcliffe efficiency (NSE) values for

  7. The impact of North Indian Ocean sea surface temperatures on the Indian summer monsoon

    NASA Astrophysics Data System (ADS)

    Levine, Richard; Turner, Andrew

    2010-05-01

    The relationship between sea surface temperature (SST) in the North Indian Ocean and Indian monsoon rainfall is investigated in both observational/re-analyses and climate model simulations. We focus on the partially land-enclosed Arabian Sea and Bay of Bengal, where SSTs are found to have significant correlations with All Indian Rainfall (AIR). This part of the Indian Ocean is therefore important for monsoon predictions, while this area tends to provide significant problems in coupled atmosphere-ocean model simulations. The observational variability of the SST-rainfall relationship is investigated on seasonal to decadal time-scales. This highlights a predominantly negative correlation over the monsoon trough area in North East India and a positive correlation over the rest of India, while these relationships are found to be weakened by the ENSO-monsoon teleconnection. Mechanisms are further investigated by performing a series of atmosphere-only model simulations using the Met Office Unified Model (MetUM). In these experiments we determine the response of the atmosphere to forced cold SST anomalies over isolated areas, which we also extend out into the equatorial Indian Ocean. The cold SSTs in the Arabian Sea and Bay of Bengal lead to a dramatic reduction in Indian rainfall, while cold biases in the equatorial Indian Ocean have the opposite effect, highlighting the competition between oceanic and continental Tropical Convergence Zones (TCZ). However, the impacts for the Arabian Sea and Bay of Bengal experiments are found to change between the pre-monsoon and post-monsoon onset periods.The impact on monsoon rainfall for cold SST biases in these regions is found to be the result of a balance between changes in regional low-level temperature gradients and the availability of moisture over the oceans, which determine the pathway of the monsoon jet and the moisture transport towards India. These experiments suggest that the intra-seasonal variability of the relationship

  8. Decreased Temperature Facilitates Short-Term Sea Star Wasting Disease Survival in the Keystone Intertidal Sea Star Pisaster ochraceus

    PubMed Central

    Kohl, Warren T.; McClure, Timothy I.; Miner, Benjamin G.

    2016-01-01

    An extensive 2013 mass mortality event along the West Coast of North America due to Sea Star Wasting Disease (SSWD) has affected at least 20 species of sea stars. Among environmental factors potentially contributing to the timing of the current outbreak, increased coastal water temperatures are hypothesized to have contributed to previous and current outbreaks of SSWD. With a laboratory experiment, we tested whether cooler temperatures, similar to average winter temperatures, compared to average summer temperatures could slow the progression of morbidity or prevent SSWD mortality entirely in Pisaster ochraceus. Sea stars housed in cooler water progressed through SSWD states more slowly than sea stars housed at summer temperatures. However, the cooler temperature did not prevent SSWD mortality, and all stars died of the disease. Our data are consistent with experimental studies and field observations during previous and current outbreaks, and support the hypothesis that changes in coastal water temperatures have influenced one of the largest disease related mass mortality events in our oceans. PMID:27128673

  9. Decreased Temperature Facilitates Short-Term Sea Star Wasting Disease Survival in the Keystone Intertidal Sea Star Pisaster ochraceus.

    PubMed

    Kohl, Warren T; McClure, Timothy I; Miner, Benjamin G

    2016-01-01

    An extensive 2013 mass mortality event along the West Coast of North America due to Sea Star Wasting Disease (SSWD) has affected at least 20 species of sea stars. Among environmental factors potentially contributing to the timing of the current outbreak, increased coastal water temperatures are hypothesized to have contributed to previous and current outbreaks of SSWD. With a laboratory experiment, we tested whether cooler temperatures, similar to average winter temperatures, compared to average summer temperatures could slow the progression of morbidity or prevent SSWD mortality entirely in Pisaster ochraceus. Sea stars housed in cooler water progressed through SSWD states more slowly than sea stars housed at summer temperatures. However, the cooler temperature did not prevent SSWD mortality, and all stars died of the disease. Our data are consistent with experimental studies and field observations during previous and current outbreaks, and support the hypothesis that changes in coastal water temperatures have influenced one of the largest disease related mass mortality events in our oceans. PMID:27128673

  10. Persistence analysis of daily mean air temperature variation in Georgia

    NASA Astrophysics Data System (ADS)

    Matcharashvili, Teimuraz; Chelidze, Tamaz; Zhukova, Natalia; Mepharidze, Ekaterine; Sborshchikov, Alexander

    2010-05-01

    Extrapolation of observed linear trends is common practice in climate change researches on different scales. In this respect it is important, that though global warming is well established, the question of persistence of trends on regional scales remain controversial. Indeed, climate change for specific region and time by definition includes more than the simple average of weather conditions. Either random events or long-term changes, or more often combinations of them, can bring about significant swings in a variety of climate indicators from one time period to the next. Therefore in order to achieve further understanding of dynamics of climate change the character of stable peculiarities of analyzed dynamics should be investigated. Analysis of the character of long range correlations in climatological time series or peculiarities of their inherent memory is motivated exactly by this goal. Such analysis carried out on a different scales may help to understand spatial and temporal features of regional climate change. In present work the problem of persistence of observed trends in air temperature time series in Georgia was investigated. Longest available mean daily temperature time series of Tbilisi (1890-2008) were analyzed. Time series on shorter time scales of five stations in the West and East Georgia also were considered as well as monthly mean temperature time series of five stations. Additionally, temporally and spatially averaged daily and monthly mean air temperature time series were analyzed. Extent of persistence in mentioned time series were evaluated using R/S analysis calculation. Detrended and Multifractal Detrended Fluctuation Analysis as well as multi scaling analysis based on CWT have been used. Our results indicate that variation of daily or monthly mean temperatures reveals clear antipersistence on whole available time scale. It seems that antipersistence on global scale is general characteristics of mean air temperature variation and is not

  11. Sea ice edge position impact on the atmospheric boundary layer temperature structure

    NASA Astrophysics Data System (ADS)

    Khavina, Elena; Repina, Irina

    2016-04-01

    Processes happening in the Arctic region nowadays strongly influence global climate system; the polar amplification effect can be considered one of the main indicators of ongoing changes. Dramatic increase in amount of ice-free areas in the Arctic Ocean, which took place in 2000s, is one of the most significant examples of climate system dynamic in polar region. High amplitude of changes in Arctic climate, both observed and predicted, and existing inaccuracies of climate and weather forecasting models, enforce the development of a more accurate one. It is essential to understand the physics of the interaction between atmosphere and ocean in the Northern Polar area (particularly in boundary layer of the atmosphere) to improve the models. Ice conditions have a great influence on the atmospheric boundary layer in the Arctic. Sea ice inhibits the heat exchange between atmosphere and ocean water during the polar winter, while the heat exchange above the ice-free areas increases rapidly. Due to those significant temperature fluctuations, turbulence of heat fluxes grows greatly. The most intensive interaction takes place at marginal ice zones, especially in case of the cold outbreak - intrusion of cooled air mass from the ice to free water area. Still, thermal structure and dynamic of the atmosphere boundary layer are not researched and described thoroughly enough. Single radio sounding observations from the planes being done, bur they do not provide high-resolution data which is necessary for study. This research is based on continuous atmosphere boundary layer temperature and sea ice observation collected in the Arctic Ocean during the two NABOS expeditions in August and September in 2013 and 2015, as well as on ice conditions satellite data (NASA TEAM 2 and VASIA 2 data processing). Atmosphere temperature data has been obtained with Meteorological Temperature Profiler MTP-5 (ATTEX, Russia). It is a passive radiometer, which provides continuous data of atmospheric

  12. Sea Breeze Forcing of Estuary Turbulence and Air-Water Exchanges

    NASA Astrophysics Data System (ADS)

    Orton, P. M.; McGillis, W. R.; Zappa, C. J.

    2010-12-01

    The sea breeze is often a dominant meteorological feature at the coastline, but little is known about its estuarine impacts. It arises on sunny days with weak synoptic weather forcing, due to O(100 km) scale atmospheric pressure differences that develop as a result of the different solar absorption properties of sea and land. Here, measurements at an anchored catamaran and meteorological stations along the Hudson River and New York Bay estuarine system are used to illustrate some basic characteristics and impacts of the feature. The sea breeze propagates inland, arriving in phase with peak solar forcing at seaward stations, but several hours later at up-estuary stations. Passage of the sea breeze front raises the water-to-air CO2 flux by 1-2 orders of magnitude, and drives turbulence comparable to spring tide levels in the upper meter of the water column, where most primary productivity occurs in this highly turbid system. Modeling and observational studies often use remotely-measured winds with quadratic parameterizations to compute air-water fluxes (e.g. momentum, CO2), and this leads to a factor of two flux error on sea breeze days during the study. We conclude with a survey of how common these features are in the Hudson as well as other estuaries.

  13. Air-Sea Spray Airborne Radar Profiler Characterizes Energy Fluxes in Hurricanes

    NASA Technical Reports Server (NTRS)

    Durden, Stephen L.; Esteban-Fermandez, D.

    2010-01-01

    A report discusses ASAP (Air-sea Spray Airborne Profiler), a dual-wavelength radar profiler that provides measurement information about the droplet size distribution (DSD) of sea-spray, which can be used to estimate heat and moisture fluxes for hurricane research. Researchers have recently determined that sea spray can have a large effect on the magnitude and distribution of the air-sea energy flux at hurricane -force wind speeds. To obtain information about the DSD, two parameters of the DSD are required; for example, overall DSD amplitude and DSD mean diameter. This requires two measurements. Two frequencies are used, with a large enough separation that the differential frequency provides size information. One frequency is 94 GHz; the other is 220 GHz. These correspond to the Rayleigh and Mie regions. Above a surface wind speed of 10 m/ s, production of sea spray grows exponentially. Both the number of large droplets and the altitude they reach are a function of the surface wind speed.

  14. Historical changes in air temperature are evident in temperature fluxes measured in the sub-soil.

    NASA Astrophysics Data System (ADS)

    Fraser, Fiona; McCormick, Benjamin; Hallett, Paul; Wookey, Philip; Hopkins, David

    2013-04-01

    Warming trends in soil temperature have implications for a plethora of soil processes, including exacerbated climate change through the net release of greenhouse gases. Whereas long-term datasets of air temperature changes are abundant, a search of scientific literature reveals a lack of information on soil temperature changes and their specific consequences. We analysed five long-term data series collected in the UK (Dundee and Armagh) and Canada (Charlottetown, Ottawa and Swift Current). They show that the temperatures of soils at 5 - 20 cm depth, and sub-soils at 30 - 150 cm depth, increased in line with air temperature changes over the period 1958 - 2003. Differences were found, however, between soil and air temperatures when data were sub-divided into seasons. In spring, soil temperature warming ranged from 0.19°C at 30 cm in Armagh to 4.30°C at 50 cm in Charlottetown. In summer, however, the difference was smaller and ranged from 0.21°C at 10 cm in Ottawa to 3.70°C at 50 cm in Charlottetown. Winter temperatures were warmer in soil and ranged from 0.45°C at 5 cm in Charlottetown to 3.76°C at 150 cm in Charlottetown. There were significant trends in changes to soil temperature over time, whereas air temperature trends tended only to be significant in winter (changes range from 1.27°C in Armagh to 3.35°C in Swift Current). Differences in the seasonal warming patterns between air and soil temperatures have potential implications for the parameterization of models of biogeochemical cycling.

  15. RELATIONSHIP BETWEEN WATER TEMPERATURES AND AIR TEMPERATURES FOR CENTRAL US STREAMS

    EPA Science Inventory

    An analysis of the relationship between air and stream water temperature records for 11 rivers located in the central United States was conducted. he reliability of commonly available water temperature records was shown to be of unequal quality. imple linear relationships between...

  16. Air Temperature Estimation over the Third Pole Using MODIS LST

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Zhang, F.; Ye, M.; Che, T.

    2015-12-01

    The Third Pole is centered on the Tibetan Plateau (TP), which is the highest large plateau around the world with extremely complex terrain and climate conditions, resulting in very scarce meteorological stations especially in the vast west region. For these unobserved areas, the remotely sensed land surface temperature (LST) can greatly contribute to air temperature estimation. In our research we utilized the MODIS LST production from both TERRA and AQUA to estimate daily mean air temperature over the TP using multiple statistical models. Other variables used in the models include longitudes, latitudes, Julian day, solar zenith, NDVI and elevation. To select a relatively optimal model, we chose six popular and representative statistical models as candidate models including the multiple linear regression (MLR), the partial least squares regression (PLS), back propagate neural network (BPNN), support vector regression (SVR), random forests (RF) and Cubist regression (CR). The performances of the six models were compared for each possible combination of LSTs at four satellite pass times and two quality situations. Eventually a ranking table consisting of optimal models for each LST combination and quality situation was built up based on the validation results. By this means, the final production is generated providing daily mean air temperature with the least cloud blockage and acceptable accuracy. The average RMSEs of cross validation are mostly around 2℃. Stratified validations were also performed to test the expansibility to unobserved and high-altitude areas of the final models selected.

  17. Modeling and imaging land-cover influences on air temperature in and near Baltimore, MD

    NASA Astrophysics Data System (ADS)

    Heisler, Gordon M.; Ellis, Alexis; Nowak, David J.; Yesilonis, Ian

    2016-04-01

    Over the course of 1681 hours between May 5 and September 30, 2006, air temperatures measured at the 1.5-m height at seven sites in and near the city of Baltimore, MD were used to empirically model Δ widehat{T} R-p , the difference in air temperature between a site in downtown Baltimore and the six other sites. Variables in the prediction equation included difference between the downtown reference and each of the other sites in upwind tree cover and impervious cover as obtained from 10-m resolution geographic information system (GIS) data. Other predictor variables included an index of atmospheric stability, topographic indices, wind speed, vapor pressure deficit, and antecedent precipitation. The model was used to map predicted hourly Δ widehat{T} R-p across the Baltimore region based on hourly weather data from the airport. Despite the numerous sources of variability in the regression modeling, the method produced reasonable map patterns of Δ widehat{T} R-p that, except for some areas evidently affected by sea breeze from the Chesapeake, closely matched results of mesoscale modeling. Potential applications include predictions of the effect of changing tree cover on air temperature in the area.

  18. Does atmospheric CO2 seasonality play an important role in governing the air-sea flux of CO2?

    NASA Astrophysics Data System (ADS)

    Halloran, P. R.

    2012-06-01

    The amplitude, phase, and form of the seasonal cycle of atmospheric CO2 concentrations varies on many time and space scales (Peters et al., 2007). Intra-annual CO2 variation is primarily driven by seasonal uptake and release of CO2 by the terrestrial biosphere (Machta et al., 1977; Buchwitz et al., 2007), with a small (Cadule et al., 2010; Heimann et al., 1998), but potentially changing (Gorgues et al., 2010) contribution from the ocean. Variability in the magnitude, spatial distribution, and seasonal drivers of terrestrial net primary productivity (NPP) will be induced by, amongst other factors, anthropogenic CO2 release (Keeling et al., 1996), land-use change (Zimov et al., 1999) and planetary orbital variability, and will lead to changes in CO2atm seasonality. Despite CO2atm seasonality being a dynamic and prominent feature of the Earth System, its potential to drive changes in the air-sea flux of CO2 has not previously (to the best of my knowledge) been explored. It is important that we investigate the impact of CO2atm seasonality change, and the potential for carbon-cycle feedbacks to operate through the modification of the CO2atm seasonal cycle, because the decision had been made to prescribe CO2atm concentrations (rather than emissions) within model simulations for the fifth IPCC climate assessment (Taylor et al., 2009). In this study I undertake ocean-model simulations within which different magnitude CO2atm seasonal cycles are prescribed. These simulations allow me to examine the effect of a change in CO2atm seasonal cycle magnitude on the air-sea CO2 flux. I then use an off-line model to isolate the drivers of the identified air-sea CO2 flux change, and propose mechanisms by which this change may come about. Three mechanisms are identified by which co-variability of the seasonal cycles in atmospheric CO2 concentration, and seasonality in sea-ice extent, wind-speed and ocean temperature, could potentially lead to changes in the air-sea flux of CO2 at mid

  19. Interannual and interdecadal variability in United States surface-air temperatures, 1910-87

    USGS Publications Warehouse

    Dettinger, M.D.; Ghil, M.; Keppenne, C.L.

    1995-01-01

    Monthly mean surface-air temperatures at 870 sites in the contiguous United States were analyzed for interannual and interdecadal variability over the time interval 1910-87. The temperatures were analyzed spatially by empirical-orthogonal-function analysis and temporally by singularspectrum analysis (SSA). The dominant modes of spatio-temporal variability are trends and nonperiodic variations with time scales longer than 15 years, decadal-scale oscillations with periods of roughly 7 and 10 years, and interannual oscillations of 2.2 and 3.3 years. Together, these modes contribute about 18% of the slower-than-annual United States temperature variance. Two leading components roughly capture the mean hemispheric temperature trend and represent a long-term warming, largest in the southwest, accompanied by cooling of the domain's southeastern quadrant. The extremes of the 2.2-year interannual oscillation characterize temperature differences between the Northeastern and Southwestern States, whereas the 3.3-year cycle is present mostly in the Western States. The 7- to 10-year oscillations are much less regular and persistent than the interannual oscillations and characterize temperature differences between the western and interior sectors of the United States. These continental- or regional-scale temperature variations may be related to climatic variations with similar periodicities, either global or centered in other regions; such variations include quasi-biennial oscillations over the tropical Pacific or North Atlantic and quasi-triennial oscillations of North Pacific sea-surface temperatures.

  20. Spatial Statistical Estimation for Massive Sea Surface Temperature Data

    NASA Astrophysics Data System (ADS)

    Marchetti, Y.; Vazquez, J.; Nguyen, H.; Braverman, A. J.

    2015-12-01

    We combine several large remotely sensed sea surface temperature (SST) datasets to create a single high-resolution SST dataset that has no missing data and provides an uncertainty associated with each value. This high resolution dataset will optimize estimates of SST in critical parts of the world's oceans, such as coastal upwelling regions. We use Spatial Statistical Data Fusion (SSDF), a statistical methodology for predicting global spatial fields by exploiting spatial correlations in the data. The main advantages of SSDF over spatial smoothing methodologies include the provision of probabilistic uncertainties, the ability to incorporate multiple datasets with varying footprints, measurement errors and biases, and estimation at any desired resolution. In order to accommodate massive input and output datasets, we introduce two modifications of the existing SSDF algorithm. First, we compute statistical model parameters based on coarse resolution aggregated data. Second, we use an adaptive spatial grid that allows us to perform estimation in a specified region of interest, but incorporate spatial dependence between locations in that region and all locations globally. Finally, we demonstrate with a case study involving estimations on the full globe at coarse resolution grid (30 km) and a high resolution (1 km) inset for the Gulf Stream region.

  1. Extracting the Global Sea Surface Temperature Evolutions of Different Timescales

    NASA Astrophysics Data System (ADS)

    Feng, J.; Wu, Z.

    2012-12-01

    A new data analysis procedure, involving empirical orthogonal functions (EOF) analysis and ensemble empirical mode decomposition (EEMD), is employed to extract the evolutions of global Sea Surface Temperature (SST) of different timescales spanning the period from 1880 to 2009 (130 yr). Specifically, EOF analysis serves as a means of lossy data compression to eliminate the spatial-temporally incoherent, noise-like part of the data; and EEMD decomposes SST time series into different time scales, which facilitates research on SST-related weather and climate phenomena that have various timescales. Through validation, it is shown that the difference between the results and the original SST time series are mostly white noises, both spatially and temporally incoherent. We apply the results to study El Niño-Southern Oscillation (ENSO) events. Each ENSO event is examined and we find an oceanic region off Baja California coast ( ) that is instrumental to some ENSO events, especially those recently called ENSO Modoki, whose initial warming may be traced back to earlier warming signals from Baja California.

  2. Using an ensemble data set of turbulent air-sea fluxes to evaluate the IPSL climate model in tropical regions

    NASA Astrophysics Data System (ADS)

    Gainusa-Bogdan, Alina; Servonnat, Jerome; Braconnot, Pascale

    2014-05-01

    Low-latitude turbulent ocean-atmosphere fluxes play a major role in the ocean and atmosphere dynamics, heat distribution and availability for meridional transport to higher latitudes, as well as for the global freshwater cycle. Their representation in coupled ocean-atmosphere models is thus of chief importance in climate simulations. Despite numerous reports of important observational uncertainties in large-scale turbulent flux products, only few model flux evaluation studies attempt to quantify and directly consider these uncertainties. To address this problem for large-scale, climatological flux evaluation, we assemble a comprehensive database of 14 climatological surface flux products, including in situ-based, satellite, hybrid and reanalysis data sets. We develop an associated analysis protocol and use it together with this database to offer an observational ensemble approach to model flux evaluation. We use this approach to perform an evaluation of the representation of the intertropical turbulent air-sea fluxes in a suite of CMIP5 historical simulations run with different recent versions of the IPSL model. To enhance model understanding, we consider both coupled and forced atmospheric model configurations. For the same purpose, we not only analyze the surface fluxes, but also their associated meteorological state variables and inter-variable relationships. We identify an important, systematic underestimation of the near-surface wind speed and a significant exaggeration of the sea-air temperature contrast in all the IPSL model versions considered. Furthermore, the coupled model simulations develop important sea surface temperature and associated air humidity bias patterns. Counterintuitively, these biases do not systematically transfer to significant biases in the surface fluxes. This is due to a combination of compensation of effects and the large flux observational spread. Our analyses reveal several inconsistencies in inter-variable relationships between

  3. Temperature-Dependent Pore Space of Sea Ice: X-ray Computed-Tomography and Dual Model Network Analysis

    NASA Astrophysics Data System (ADS)

    Pringle, D.; Miner, J.; Glantz, R.; Hilpert, M.; Eicken, H.

    2006-12-01

    Sea ice provides a mechanical and thermal barrier between the atmosphere and ocean at high latitudes and is an important component of the climate system. It is a composite material with temperature- and salinity- dependent volume fractions of ice, brine and air. Our present interest is the microstructural control of the (hydraulic) permeability, which affects the melt-season albedo (shortwave reflectance) of sea ice by enabling or restricting the drainage of surface meltwater, and is also relevant for other processes including nutrient delivery to microorganisms colonizing the lower layers of the ice sheet. At low temperatures, the relative brine volume (porosity) is small, the inclusions are disconnected, and the permeability is small. The relative brine volume increases with temperature, and the permeability increases strongly above a porosity of ~5%. We have imaged the pore space of natural and laboratory-grown sea ice with x-ray micro-computed tomography (CT) over a temperature range typical of that in the Arctic ( - 25°C to -3°C) and which spans corresponding changes in the permeability by several orders of magnitude. Based on our `Dual Model' approach, we identify pore bodies and throats from the segmented CT data to eventually derive a pore network. We characterize the temperature-dependence of the pore space connectivity and apply critical path analysis to investigate the dependence of permeability on pore microstructural evolution.

  4. Comparison of geographical trend patterns in sea level and sea surface temperature in the Pacific Ocean during 1993-2011

    NASA Astrophysics Data System (ADS)

    Palanisamy, Hindumathi; Cazenave, Anny; Delcroix, Thierry; Meyssignac, Benoit; Balmaseda, Magdalena; Merchant, Christopher

    2013-04-01

    It is now well established that geographical trend patterns in satellite altimetry-based sea level are mostly caused by non uniform steric trend patterns, the largest contribution being due to the thermosteric component. In the Pacific Ocean, the observed sea level trend pattern over 1993-2011 results from a superposition two types of signals: (1) a strong positive trend V-shaped anomaly located 120°E and 160° E in longitude and ~20°S-20°N in latitude and (2) another V-shaped anomaly of much broader scale -extending to mid-latitudes in the central Pacific-, quite similar to the dominant large-scale trend pattern observed in sea surface temperature (SST). Previous studies have shown that the type (1) signal is related to El Nino Southern Oscillation (ENSO). The type (2) signal reflects the Pacific Decadal Oscillation (PDO), the dominant component of large-scale SST variability in the Pacific. In this study, we analyze altimetry-based sea level, steric sea level and SST over the 1993-2011 time span to discriminate between the near surface and deeper thermosteric contributions to sea level. The sea level and SST data are based on the recently available products from the ESA Climate Change Initiative project and several other products like HadiSST, ERAINTERIM. Steric data are based on an updated version of the Ishii and Kimoto (2009) data. We compute the thermosteric contribution to sea level in different layers from the surface to the 700 m depth, and through correlation and Empirical Orthogonal Function analyses, explore the spatio-temporal coherence between the three variables (sea level, depth-dependent steric sea level and SST).

  5. Development of an Eddy Covariance System for Air-Sea Carbon Dioxide Exchange

    NASA Astrophysics Data System (ADS)

    Miller, S. D.; Marandino, C. A.; McCormick, C.; Saltzman, E. S.

    2006-12-01

    We are developing a ship-based system to measure the air-sea pCO2 gradient and air-sea turbulent flux of CO2 over the ocean. The eddy covariance flux system uses off-the-shelf instruments to measure the turbulent wind vector (Campbell Scientific CSAT3 sonic anemometer), platform motion (Systron Donner Motion Pak II), and carbon dioxide molar density (LiCor 7000 Infrared Gas Analyzer). Two major sources of uncertainty in calculated fluxes are the effect of water vapor fluctuations on air density fluctuations (the WPL effect, Webb, Pearman and Leuning. 1980), and a spurious CO2 signal due to the sensitivity of the gas analyzer to platform motion (McGillis et al., 1998). Two flux systems were deployed side-by-side on a cruise from Manzanillo, Mexico to Puntas Arenas, Chile, in January 2006. Results from the cruise are presented, with a focus on our attempts to reduce biases in the calculated air-sea CO2 flux due to the WPL effect and the motion sensitivity of the gas analyzer.

  6. Air Cooling for High Temperature Power Electronics (Presentation)

    SciTech Connect

    Waye, S.; Musselman, M.; King, C.

    2014-09-01

    Current emphasis on developing high-temperature power electronics, including wide-bandgap materials such as silicon carbide and gallium nitride, increases the opportunity for a completely air-cooled inverter at higher powers. This removes the liquid cooling system for the inverter, saving weight and volume on the liquid-to-air heat exchanger, coolant lines, pumps, and coolant, replacing them with just a fan and air supply ducting. We investigate the potential for an air-cooled heat exchanger from a component and systems-level approach to meet specific power and power density targets. A proposed baseline air-cooled heat exchanger design that does not meet those targets was optimized using a parametric computational fluid dynamics analysis, examining the effects of heat exchanger geometry and device location, fixing the device heat dissipation and maximum junction temperature. The CFD results were extrapolated to a full inverter, including casing, capacitor, bus bar, gate driver, and control board component weights and volumes. Surrogate ducting was tested to understand the pressure drop and subsequent system parasitic load. Geometries that met targets with acceptable loads on the system were down-selected for experimentation. Nine baseline configuration modules dissipated the target heat dissipation, but fell below specific power and power density targets. Six optimized configuration modules dissipated the target heat load, exceeding the specific power and power density targets. By maintaining the same 175 degrees C maximum junction temperature, an optimized heat exchanger design and higher device heat fluxes allowed a reduction in the number of modules required, increasing specific power and power density while still maintaining the inverter power.

  7. Global surface air temperature variations: 1851-1984

    SciTech Connect

    Jones, P.D.; Raper, S.C.B.; Kelly, P.M.

    1986-11-01

    Many attempts have been made to combine station surface air temperature data into an average for the Northern Hemisphere. Fewer attempts have been made for the Southern Hemisphere because of the unavailability of data from the Antarctic mainland before the 1950s and the uncertainty of making a hemispheric estimate based solely on land-based analyses for a hemisphere that is 80% ocean. Past estimates have been based largely on data from the World Weather Records (Smithsonian Institution, 1927, 1935, 1947, and U.S. Weather Bureau, 1959-82) and have been made without considerable effort to detect and correct station inhomogeneities. Better estimates for the Southern Hemisphere are now possible because of the availability of 30 years of climatological data from Antarctica. The mean monthly surface air temperature anomalies presented in this package for the than those previously published because of the incorporation of data previously hidden away in archives and the analysis of station homogeneity before estimation.

  8. On the use of a coupled ocean-atmosphere-wave model during an extreme cold air outbreak over the Adriatic Sea

    NASA Astrophysics Data System (ADS)

    Ricchi, Antonio; Miglietta, Mario Marcello; Falco, Pier Paolo; Benetazzo, Alvise; Bonaldo, Davide; Bergamasco, Andrea; Sclavo, Mauro; Carniel, Sandro

    2016-05-01

    An intense cold air outbreak affected the northern Adriatic Sea during winter 2012, determining an exceptional persistence of northeasterly Bora wind over the basin, which lasted for about 3 weeks. The cold air coming from the Balkans produced icing in the Venice lagoon and very intense snowfall in the Apennines Mountains and even near the coasts. In order to understand the importance and role of air-sea interactions for the evolution of the atmospheric fields, simulations with the Weather Research and Forecasting (WRF) model encompassing the whole period have been performed using sea surface temperature (SST) fields with an increasing level of complexity. Starting from a large-scale static sea temperature, the SST in the initial and boundary conditions has been progressively made more realistic. First, a more refined field, retrieved from a satellite radiometer was used; then, the same field was updated every 6 h. Next, the effect of including a simplified 1D ocean model reproducing the Oceanic Mixed Layer (OML) evolution has been tested. Finally, the potential improvements coming from a coupled description of atmosphere-ocean and atmosphere-ocean-waves interactions have been explored within the Coupled Ocean-Atmosphere-Wave Sediment Transport (COAWST) modeling system. Results highlight that the energy exchange between air and sea does not significantly impact the atmospheric fields, in particular 10 m wind and 2 m temperature, also because of the geography of the basin and the predominance of synoptic-scale flow in intense events of Bora, in the northern Adriatic. However, when sensible and latent heat fluxes, which are dependent on atmospheric and oceanic variables, are analyzed, the more realistic representation of SST drastically improves the model performances.

  9. Large Scale Variability of Phytoplankton Blooms in the Arctic and Peripheral Seas: Relationships with Sea Ice, Temperature, Clouds, and Wind

    NASA Technical Reports Server (NTRS)

    Comiso, Josefino C.; Cota, Glenn F.

    2004-01-01

    Spatially detailed satellite data of mean color, sea ice concentration, surface temperature, clouds, and wind have been analyzed to quantify and study the large scale regional and temporal variability of phytoplankton blooms in the Arctic and peripheral seas from 1998 to 2002. In the Arctic basin, phytoplankton chlorophyll displays a large symmetry with the Eastern Arctic having about fivefold higher concentrations than those of the Western Arctic. Large monthly and yearly variability is also observed in the peripheral seas with the largest blooms occurring in the Bering Sea, Sea of Okhotsk, and the Barents Sea during spring. There is large interannual and seasonal variability in biomass with average chlorophyll concentrations in 2002 and 2001 being higher than earlier years in spring and summer. The seasonality in the latitudinal distribution of blooms is also very different such that the North Atlantic is usually most expansive in spring while the North Pacific is more extensive in autumn. Environmental factors that influence phytoplankton growth were examined, and results show relatively high negative correlation with sea ice retreat and strong positive correlation with temperature in early spring. Plankton growth, as indicated by biomass accumulation, in the Arctic and subarctic increases up to a threshold surface temperature of about 276-277 degree K (3-4 degree C) beyond which the concentrations start to decrease suggesting an optimal temperature or nutrient depletion. The correlation with clouds is significant in some areas but negligible in other areas, while the correlations with wind speed and its components are generally weak. The effects of clouds and winds are less predictable with weekly climatologies because of unknown effects of averaging variable and intermittent physical forcing (e.g. over storm event scales with mixing and upwelling of nutrients) and the time scales of acclimation by the phytoplankton.

  10. Surfactant control of air-sea gas exchange across contrasting biogeochemical regimes

    NASA Astrophysics Data System (ADS)

    Pereira, Ryan; Schneider-Zapp, Klaus; Upstill-Goddard, Robert

    2014-05-01

    Air-sea gas exchange is important to the global partitioning of CO2.Exchange fluxes are products of an air-sea gas concentration difference, ΔC, and a gas transfer velocity, kw. The latter is controlled by the rate of turbulent diffusion at the air-sea interface but it cannot be directly measured and has a high uncertainty that is now considered one of the greatest challenges to quantifying net global air-sea CO2 exchange ...(Takahashi et al., 2009). One important control on kw is exerted by sea surface surfactants that arise both naturally from biological processes and through anthropogenic activity. They influence gas exchange in two fundamental ways: as a monolayer physical barrier and through modifying sea surface hydrodynamics and hence turbulent energy transfer. These effects have been demonstrated in the laboratory with artificial surfactants ...(Bock et al., 1999; Goldman et al., 1988) and through purposeful surfactant releases in coastal waters .(.).........().(Brockmann et al., 1982) and in the open ocean (Salter et al., 2011). Suppression of kwin these field experiments was ~5-55%. While changes in both total surfactant concentration and the composition of the natural surfactant pool might be expected to impact kw, the required in-situ studies are lacking. New data collected from the coastal North Sea in 2012-2013 shows significant spatio-temporal variability in the surfactant activity of organic matter within the sea surface microlayer that ranges from 0.07-0.94 mg/L T-X-100 (AC voltammetry). The surfactant activities show a strong winter/summer seasonal bias and general decrease in concentration with increasing distance from the coastline possibly associated with changing terrestrial vs. phytoplankton sources. Gas exchange experiments of this seawater using a novel laboratory tank and gas tracers (CH4 and SF6) demonstrate a 12-45% reduction in kw compared to surfactant-free water. Seasonally there is higher gas exchange suppression in the summer

  11. Climatology and Real-Data Simulations of Snow Bands over the English Channel and Irish Sea during Cold-Air Outbreaks

    NASA Astrophysics Data System (ADS)

    Norris, J.; Vaughan, G.; Schultz, D. M.

    2012-04-01

    During the winters of 2009—2010 and 2010—2011, anti-cyclonic blocking over the north Atlantic led to cold, dry air being advected over the UK from the north and east, generating widespread snow depths not seen since the early 1980s. The societal and economical impacts of this snow were severe and diverse, including those on transport, industry, commerce, emergency services, and retail. The most distinctive precipitation features during these winters formed over the English Channel and Irish Sea, where convection frequently organised into bands, as diagnosed from Met Office NIMROD precipitation radar images, forming along the major axis of each body of water (hereafter, sea) when the boundary-layer flow was roughly parallel to each of those axes (hereafter, along-sea). In this study, we address the atmospheric conditions, diagnosed from soundings from suitable locations, at times when bands were observed and at times that they were not, during the cold-air outbreaks in these winters. We find that, for both seas, a band was present the majority of times that the 850-hPa flow was along-sea. We subsequently find that, of these times of along-sea flow, for both seas, 850-hPa wind speed and surface-to-850-hPa temperature difference were significantly greater when bands were present than when they were not. Real-data simulations using the Weather Research and Forecasting (WRF) model are then presented for a typical band over each sea and the model is found to be accurate in reproducing the structures observed on radar. Output from control runs for each band is compared to that in which topography, surface heat fluxes, and land-sea borders are each removed in turn in order to investigate how the low-level flow evolves to generate the observed bands.

  12. Industrial applications of MHD high temperature air heater technology

    NASA Astrophysics Data System (ADS)

    Saari, D. P.; Fenstermacher, J. E.; White, L. R.; Marksberry, C. L.

    1981-12-01

    The MHD high temperature air heater (HTAH) requires technology beyond the current state-of-the-art of industrial regenerative heaters. Specific aspects of HTAH technology which may find other application include refractory materials and valves resistant to the high temperature, corrosive, slag-bearing gas, materials resistant to cyclic thermal stresses, high temperature support structures for the cored brick bed, regenerative heater operating techniques for preventing accumulation of slag in the heater, and analytical tools for computing regenerative heater size, cost, and performance. Areas where HTAH technology may find application include acetylene/ethylene production processes, flash pyrolysis of coal, high temperature gas reactors, coal gasification processes, various metallurgical processes, waste incineration, and improvements to existing regenerator technology such as blast furnace stoves and glass tank regenerators.

  13. Evidence of Lunar Phase Influence on Global Surface Air Temperatures

    NASA Technical Reports Server (NTRS)

    Anyamba, Ebby; Susskind, Joel

    2000-01-01

    Intraseasonal oscillations appearing in a newly available 20-year record of satellite-derived surface air temperature are composited with respect to the lunar phase. Polar regions exhibit strong lunar phase modulation with higher temperatures occurs near full moon and lower temperatures at new moon, in agreement with previous studies. The polar response to the apparent lunar forcing is shown to be most robust in the winter months when solar influence is minimum. In addition, the response appears to be influenced by ENSO events. The highest mean temperature range between full moon and new moon in the polar region between 60 deg and 90 deg latitude was recorded in 1983, 1986/87, and 1990/91. Although the largest lunar phase signal is in the polar regions, there is a tendency for meridional equatorward progression of anomalies in both hemispheres so that the warning in the tropics occurs at the time of the new moon.

  14. The Air-Sea Interface and Surface Stress under Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Soloviev, Alexander; Lukas, Roger; Donelan, Mark; Ginis, Isaac

    2013-04-01

    Air-sea interaction dramatically changes from moderate to very high wind speed conditions (Donelan et al. 2004). Unresolved physics of the air-sea interface are one of the weakest components in tropical cyclone prediction models. Rapid disruption of the air-water interface under very high wind speed conditions was reported in laboratory experiments (Koga 1981) and numerical simulations (Soloviev et al. 2012), which resembled the Kelvin-Helmholtz instability at an interface with very large density difference. Kelly (1965) demonstrated that the KH instability at the air-sea interface can develop through parametric amplification of waves. Farrell and Ioannou (2008) showed that gustiness results in the parametric KH instability of the air-sea interface, while the gusts are due to interacting waves and turbulence. The stochastic forcing enters multiplicatively in this theory and produces an exponential wave growth, augmenting the growth from the Miles (1959) theory as the turbulence level increases. Here we complement this concept by adding the effect of the two-phase environment near the mean interface, which introduces additional viscosity in the system (turning it into a rheological system). The two-phase environment includes air-bubbles and re-entering spray (spume), which eliminates a portion of the wind-wave wavenumber spectrum that is responsible for a substantial part of the air sea drag coefficient. The previously developed KH-type interfacial parameterization (Soloviev and Lukas 2010) is unified with two versions of the wave growth model. The unified parameterization in both cases exhibits the increase of the drag coefficient with wind speed until approximately 30 m/s. Above this wind speed threshold, the drag coefficient either nearly levels off or even slightly drops (for the wave growth model that accounts for the shear) and then starts again increasing above approximately 65 m/s wind speed. Remarkably, the unified parameterization reveals a local minimum

  15. Impact of Interdecadal Sea Level and Sea Surface Temperature Variability on Primary Productivity and Harmful Algal Blooms in Southern California

    NASA Astrophysics Data System (ADS)

    Perry, K. L.

    2014-12-01

    Harmful Algal Blooms (HABs) are increasing in frequency and intensity on global, regional and local scales. Although climate change has been suggested as one of the key factors, very few interdecadal studies comparing HABs to low frequency physical forcing have been performed. Interannual to interdecadal variability in sea level and sea surface temperature along the Southern California Coast have been shown to have high correlation with the El Nino-La Nina signal. This is important in the study of phytoplankton, because abnormally low sea level corresponds to increased sea surface nutrient concentrations in this region. The California current is stronger during these times, and the higher nutrient water found to the north is advected southward. We have determined that primary productivity is most highly correlated with interdecadal sea level variability derived from tide gage data at a lag of approximately 2 months. This is consistent with previous zooplankton studies. In preparation for a potential El Nino event, we have expanded our analysis to include parameters such as sea surface temperature, salinity and nutrient concentrations from spaceborne and in situ instruments. We have also expanded our research to allow for analysis of several of the most prevalent HAB species. This work is the first step in our effort to create a model to predict and locate Southern California HAB events in the future.

  16. A case study of sea breeze blocking regulated by sea surface temperature along the English south coast

    NASA Astrophysics Data System (ADS)

    Sweeney, J. K.; Chagnon, J. M.; Gray, S. L.

    2014-05-01

    The sensitivity of sea breeze structure to sea surface temperature (SST) and coastal orography is investigated in convection-permitting Met Office Unified Model simulations of a case study along the south coast of England. Changes in SST of 1 K are shown to significantly modify the structure of the sea breeze immediately offshore. On the day of the case study, the sea breeze was partially blocked by coastal orography, particularly within Lyme Bay. The extent to which the flow is blocked depends strongly on the static stability of the marine boundary layer. In experiments with colder SST, the marine boundary layer is more stable, and the degree of blocking is more pronounced. Although a colder SST would also imply a larger land-sea temperature contrast and hence a stronger onshore wind - an effect which alone would discourage blocking - the increased static stability exerts a dominant control over whether blocking takes place. The implications of prescribing fixed SST from climatology in numerical weather prediction model forecasts of the sea breeze are discussed.

  17. Spatial and temporal variability of heat, water vapor, carbon dioxide, and momentum air-sea exchange in a coastal environment

    NASA Astrophysics Data System (ADS)

    Crawford, Timothy L.; McMillen, Robert T.; Meyers, Tilden P.; Hicks, Bruce B.

    1993-07-01

    Simultaneous eddy correlation measurements from a tower, a boat, and an aircraft platform are used to assess the spatial and temporal variability of heat, moisture, momentum, and CO2 turbulent fluxes in a coastal environment. Dissolved CO2 in the coastal waters and atmospheric CO2 concentrations were continuously measured throughout the experiment. Good agreement was found among the different sensing systems. Air-to-sea gas, momentum, and energy flux density measurements are shown to be achievable from both a boat and an aircraft. The observed 10 W/sq m sensible heat flux was time-invariant but did not vary spatially with surface temperature, which was strongly correlated with ocean depth. The 100 to 200 W/sq m evaporative moisture flux dominated energy exchange and varied both in time and space. No consistent diurnal variation was observed, but the spatial trend also followed surface temperature. CO2 exchange exhibited large spatial and temporal variance.

  18. Role of the North Pacific sea surface temperature in the East Asian winter monsoon decadal variability

    NASA Astrophysics Data System (ADS)

    Sun, Jianqi; Wu, Sha; Ao, Juan

    2016-06-01

    In this study, a possible mechanism for the decadal variability in the East Asian winter monsoon (EAWM) is proposed. Specifically, the North Pacific sea surface temperature (SST) may play an important role. An analysis of the observations shows that the North Pacific SST has a remarkable decadal pattern whose phase shifted around the mid-1980s. This North Pacific SST decadal pattern can weaken the East Asian trough and enhance the North Pacific Oscillation through changing air-sea interactions over the North Pacific. The weak East Asian trough enhances the zonal circulation and weakens the meridional circulation over East Asia, consequently leading to a weaker southward cold surge and East Asia warming around the mid-1980s. The numerical experiment further confirms the pronounced physical processes. In addition, over the longer period of 1871-2012, the indices of the EAWM and North Pacific SST decadal pattern are also highly consistent on the decadal timescale, which further confirms the impact of the North Pacific SST decadal pattern on the EAWM decadal variability.

  19. Clouds, radiation, and the diurnal cycle of sea surface temperature in the tropical Western Pacific

    SciTech Connect

    Webster, P.J.; Clayson, C.A.; Curry, J.A.

    1996-04-01

    In the tropical Western Pacific (TWP) Ocean, the clouds and the cloud-radiation feedback can only be understood in the context of air/sea interactions and the ocean mixed layer. Considerable interest has been shown in attempting to explain why sea surface temperature (SST) rarely rises above 30{degrees}C, and gradients of the SST. For the most part, observational studies that address this issue have been conducted using monthly cloud and SST data, and the focus has been on intraseasonal and interannual time scales. For the unstable tropical atmosphere, using monthly averaged data misses a key feedback between clouds and SST that occurs on the cloud-SST coupling time scale, which was estimated to be 3-6 days for the unstable tropical atmosphere. This time scale is the time needed for a change in cloud properties, due to the change of ocean surface evaporation caused by SST variation, to feed back to the SST variation, to feed back to the SST through its effect on the surface heat flux. This paper addresses the relationship between clouds, surface radiation flux and SST of the TWP ocean over the diurnal cycle.

  20. Extended Reconstructed Sea Surface Temperature Version 4 (ERSST.v4), Part I. Upgrades and Intercomparisons

    NASA Astrophysics Data System (ADS)

    Huang, B.; Freeman, E.; Lawrimore, J. H.; Liu, W.; Peterson, T. C.; Smith, T. M.; Thorne, P.; Woodruff, S.; Zhang, H. M.; Banzon, P. V. F.

    2014-12-01

    The monthly Extended Reconstructed Sea Surface Temperature (ERSST) dataset has been revised herein to version 4 (v4) from v3b. Major revisions include: updated and substantially more complete input data from the International Comprehensive Ocean-Atmosphere Data Set (ICOADS) Release 2.5; revised Empirical Orthogonal Teleconnections (EOTs) and EOT acceptance criterion; updated sea surface temperature (SST) quality control procedures; revised SST anomaly (SSTA) evaluation methods; updated bias adjustments of ship SSTs using Hadley Nighttime Marine Air Temperature version 2 (HadNMAT2); and a buoy SST bias adjustment not previously made in v3b. Tests showed that the revisions to ship SST bias adjustment in ERSST.v4 are dominant among all revisions and updates. The effect is to make SST 0.1°C-0.2°C lower north of 30°S but 0.1°C-0.2°C higher south of 30°S in ERSST.v4 than in ERSST.v3b before 1940. In comparison with the UK Met Office SST product (HadSST3), the ship SST bias adjustment in ERSST.v4 is 0.1°C-0.2°C lower in the tropics but 0.1°C-0.2°C higher in the mid-latitude oceans both before 1940 and from 1945 to 1970. The 1901-2013 global SST trend changed from 0.71°C/century in v3b to 0.73°C/century in ERSST.v4. The tests also showed that, when compared with v3b, SSTAs in ERSST.v4 can substantially better represent the El Niño/La Niña behavior when observations are sparse before 1940.

  1. Terrestrial basking sea turtles are responding to spatio-temporal sea surface temperature patterns

    PubMed Central

    Van Houtan, Kyle S.; Halley, John M.; Marks, Wendy

    2015-01-01

    Naturalists as early as Darwin observed terrestrial basking in green turtles (Chelonia mydas), but the distribution and environmental influences of this behaviour are poorly understood. Here, we examined 6 years of daily basking surveys in Hawaii and compared them with the phenology of local sea surface temperatures (SST). Data and models indicated basking peaks when SST is coolest, and we found this timeline consistent with bone stress markings. Next, we assessed the decadal SST profiles for the 11 global green turtle populations. Basking generally occurs when winter SST falls below 23°C. From 1990 to 2014, the SST for these populations warmed an average 0.04°C yr−1 (range 0.01–0.09°C yr−1); roughly three times the observed global average over this period. Owing to projected future warming at basking sites, we estimated terrestrial basking in green turtles may cease globally by 2100. To predict and manage for future climate change, we encourage a more detailed understanding for how climate influences organismal biology. PMID:25589483

  2. Seasonal Prediction of North American Surface Air Temperatures Using Space-Time Principal Components.

    NASA Astrophysics Data System (ADS)

    Vautard, Robert; Plaut, Guy; Wang, Risheng; Brunet, Gilbert

    1999-02-01

    The statistical model proposed by Vautard et al. is applied to the seasonal prediction of surface air temperatures over North America (Canada and the United States). This model is based on sea surface temperature predictors filtered by multichannel singular spectrum analysis (MSSA), which is equivalent here to a nonseasonal version of extended EOF analysis. Several versions of the MSSA model are proposed. The most successful one is based on a two-step procedure consisting in a prior prediction of filtered sea surface temperatures followed by a predictand specification stage.The MSSA model is compared with the recent prediction technique based on canonical correlation analysis (CCA). The former model turns out, in this application, to be more skillful in most seasons than the latter. The differences are, however, marginal. The authors argue that these differences are due to the nonseasonal nature of the MSSA model and to overfitting problems inherent to CCA. Another advantage of the MSSA model relative to CCA is the possibility of easily transforming deterministic continuous forecasts into probabilistic categorical forecasts.The geographical distribution of prediction skill across North America is studied. Canada turns out to be the country where skill is most significant. During winter, high skill values are also found over the southeastern United States.

  3. Millennial-scale Atlantic/East Pacific sea surface temperature linkages during the last 100,000 years

    NASA Astrophysics Data System (ADS)

    Dubois, Nathalie; Kienast, Markus; Kienast, Stephanie S.; Timmermann, Axel

    2014-06-01

    Amplifying both internally generated variability and remote climate signals from the Atlantic Ocean via coupled air-sea instabilities, the eastern tropical Pacific (ETP) is well situated to detect past climate changes and variations in Central American wind systems that dynamically link the Atlantic and the Pacific. Here we compare new and previously published alkenone-based sea surface temperature (SST) reconstructions from diverse environments within the ETP, i.e. the Eastern Pacific Warm Pool (EPWP), the equatorial and the northern Peruvian Upwelling regions over the past 100,000 yr. Over this time period, a fairly constant meridional temperature gradient across the region is observed, indicating similar hydrographic conditions during glacial and interglacial periods. The data further reveal that millennial-scale cold events associated with massive iceberg surges in the North Atlantic (Heinrich events) generate cooling in the ETP from ∼8°N to ∼2°S. Data from Heinrich event 1, however, indicate that the response changes sign south of 2°S. These millennial-scale alterations of the SST pattern across diverse environments of the ETP support previous climate modeling experiments that suggested an Atlantic-Pacific connection caused by the intensification of the Central American gap winds, enhanced upwelling and mixing north of the equator and supported by positive air-sea feedbacks in the eastern tropical Pacific.

  4. Black sea surface temperature anomaly on 5th August 1998 and the ozone layer thickness

    NASA Astrophysics Data System (ADS)

    Manev, A.; Palazov, K.; Raykov, St.; Ivanov, V.

    2003-04-01

    BLACK SEA SURFACE TEMPERATURE ANOMALY ON 5th AUGUST 1998 AND THE OZONE LAYER THICKNESS A. Manev , K. Palazov , St. Raykov, V. Ivanov Solar Terrestrial Influences Laboratory, Bulgarian Academy of Sciences amanev@abv.bg This paper focuses on the peculiarities of the Black Sea surface temperature anomaly on 05.08.1998. Researching the daily temperature changes in a number of control fields in the course of 8-10 years, we have found hidden correlations and anomalous deviations in the sea surface temperatures on a global scale. Research proves the statistical reliability of the temperature anomaly on the entire Black Sea surface registered on 04.-05.08.1998. In the course of six days around these dates the temperatures are up to 2°C higher than the maximum temperatures in this period in the other seven years. A more detailed analysis of the dynamics of the anomaly required the investigation of five Black Sea surface characteristic zones of 75x75 km. The analysis covers the period 20 days - 10 days before and 10 days after the anomaly. Investigations aimed at interpreting the reasons for the anomalous heating of the surface waters. We have tried to analyze the correlation between sea surface temperature and the global ozone above the Black Sea by using simultaneously data from the two satellite systems NOAA and TOMS. Methods of processing and comparing the data from the two satellite systems are described. The correlation coefficients values for the five characteristic zones are very high and close, which proves that the character of the correlation ozone - sea surface temperature is the same for the entire Black Sea surface. Despite the high correlation coefficient, we have proved that causality between the two phenomena at the time of the anomaly does not exit.

  5. Mueller matrix imaging of targets under an air-sea interface.

    PubMed

    Zhai, Peng-Wang; Kattawar, George W; Yang, Ping

    2009-01-10

    The Mueller matrix imaging method is a powerful tool for target detection. In this study, the effect of the air-sea interface on the detection of underwater objects is studied. A backward Monte Carlo code has been developed to study this effect. The main result is that the reflection of the diffuse sky light by the interface reduces the Mueller image contrast. If the air-sea interface is ruffled by wind, the distinction between different regions of the underwater target is smoothed out. The effect of the finite size of an active light source is also studied. The image contrast is found to be relatively insensitive to the size of the light source. The volume scattering function plays an important role on the underwater object detection. Generally, a smaller asymmetry parameter decreases the contrast of the polarimetry images. PMID:19137035

  6. Size distribution of oceanic air bubbles entrained in sea-water by wave-breaking

    NASA Technical Reports Server (NTRS)

    Resch, F.; Avellan, F.

    1982-01-01

    The size of oceanic air bubbles produced by whitecaps and wave-breaking is determined. The production of liquid aerosols at the sea surface is predicted. These liquid aerosols are at the origin of most of the particulate materials exchanged between the ocean and the atmosphere. A prototype was designed and built using an optical technique based on the principle of light scattering at an angle of ninety degrees from the incident light beam. The output voltage is a direct function of the bubble diameter. Calibration of the probe was carried out within a range of 300 microns to 1.2 mm. Bubbles produced by wave-breaking in a large air-sea interaction simulating facility. Experimental results are given in the form of size spectrum.

  7. Testing for deterministic trends in global sea surface temperature

    NASA Astrophysics Data System (ADS)

    Barbosa, Susana

    2010-05-01

    The identification and estimation of trends is a frequent and fundamental task in the analysis of hydrometeorological records. The task is challenging because even time series generated by purely random processes can exhibit visually appealing trends that can be misleadingly taken as evidence of non-stationary behavior. Hydrometeorological time series exhibiting long range dependence can also exhibit trend-like features that can be mistakenly interpreted as a trend, leading to erroneous forecasts and interpretations of the variability structure of the series, particularly in terms of statistical uncertainty. In practice the overwhelming majority of trends in hydro-climatic records are reported as the slope from a linear regression model. It is therefore important to assess when a linear regression model is a reasonable description for a time series. One could think that if a derived slope is statistically significant, particularly if inference is performed carefully, the linear regression model would be appropriate. However, stochastic features, such as long-range dependence can produce statistically significant linear trends. Therefore, the plausibility of the linear regression model needs to be tested itself, in addition to testing if the trend slope is statistically significant. In this work parametric statistical tests are applied in order to evaluate the trend-stationary assumption in global sea surface temperature for the period from January 1900 to December 2008. The fit of a linear deterministic model to the spatially-averaged global mean SST series yields a statistically significant positive slope, suggesting an increasing linear trend. However, statistical testing rejects the hypothesis of a deterministic linear trend with a stationary stochastic noise. This is supported by the form of the temporal structure of the detrended series, which exhibits large positive values up to lags of 5 years, indicating temporal persistence.

  8. Sampling Errors in Satellite-derived Infrared Sea Surface Temperatures

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Minnett, P. J.

    2014-12-01

    Sea Surface Temperature (SST) measured from satellites has been playing a crucial role in understanding geophysical phenomena. Generating SST Climate Data Records (CDRs) is considered to be the one that imposes the most stringent requirements on data accuracy. For infrared SSTs, sampling uncertainties caused by cloud presence and persistence generate errors. In addition, for sensors with narrow swaths, the swath gap will act as another sampling error source. This study is concerned with quantifying and understanding such sampling errors, which are important for SST CDR generation and for a wide range of satellite SST users. In order to quantify these errors, a reference Level 4 SST field (Multi-scale Ultra-high Resolution SST) is sampled by using realistic swath and cloud masks of Moderate Resolution Imaging Spectroradiometer (MODIS) and Advanced Along Track Scanning Radiometer (AATSR). Global and regional SST uncertainties are studied by assessing the sampling error at different temporal and spatial resolutions (7 spatial resolutions from 4 kilometers to 5.0° at the equator and 5 temporal resolutions from daily to monthly). Global annual and seasonal mean sampling errors are large in the high latitude regions, especially the Arctic, and have geographical distributions that are most likely related to stratus clouds occurrence and persistence. The region between 30°N and 30°S has smaller errors compared to higher latitudes, except for the Tropical Instability Wave area, where persistent negative errors are found. Important differences in sampling errors are also found between the broad and narrow swath scan patterns and between day and night fields. This is the first time that realistic magnitudes of the sampling errors are quantified. Future improvement in the accuracy of SST products will benefit from this quantification.

  9. Data-Model Comparison of Pliocene Sea Surface Temperature

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  10. Small Autonomous Air/Sea System Concepts for Coast Guard Missions

    NASA Technical Reports Server (NTRS)

    Young, Larry A.

    2005-01-01

    A number of small autonomous air/sea system concepts are outlined in this paper that support and enhance U.S. Coast Guard missions. These concepts draw significantly upon technology investments made by NASA in the area of uninhabited aerial vehicles and robotic/intelligent systems. Such concepts should be considered notional elements of a greater as-yet-not-defined robotic system-of-systems designed to enable unparalleled maritime safety and security.

  11. An assessment of the Atlantic and Arctic sea-air CO2 fluxes, 1990-2009

    NASA Astrophysics Data System (ADS)

    Schuster, U.; McKinley, G. A.; Bates, N.; Chevallier, F.; Doney, S. C.; Fay, A. R.; González-Dávila, M.; Gruber, N.; Jones, S.; Krijnen, J.; Landschützer, P.; Lefèvre, N.; Manizza, M.; Mathis, J.; Metzl, N.; Olsen, A.; Rios, A. F.; Rödenbeck, C.; Santana-Casiano, J. M.; Takahashi, T.; Wanninkhof, R.; Watson, A. J.

    2013-01-01

    The Atlantic and Arctic Oceans are critical components of the global carbon cycle. Here we quantify the net sea-air CO2 flux, for the first time, across different methodologies for consistent time and space scales for the Atlantic and Arctic basins. We present the long-term mean, seasonal cycle, interannual variability and trends in sea-air CO2 flux for the period 1990 to 2009, and assign an uncertainty to each. We use regional cuts from global observations and modeling products, specifically a pCO2-based CO2 flux climatology, flux estimates from the inversion of oceanic and atmospheric data, and results from six ocean biogeochemical models. Additionally, we use basin-wide flux estimates from surface ocean pCO2 observations based on two distinct methodologies. Our estimate of the contemporary sea-air flux of CO2 (sum of anthropogenic and natural components) by the Atlantic between 40° S and 79° N is -0.49 ± 0.05 Pg C yr-1, and by the Arctic it is -0.12 ± 0.06 Pg C yr-1, leading to a combined sea-air flux of -0.61 ± 0.06 Pg C yr-1 for the two decades (negative reflects ocean uptake). We do find broad agreement amongst methodologies with respect to the seasonal cycle in the subtropics of both hemispheres, but not elsewhere. Agreement with respect to detailed signals of interannual variability is poor, and correlations to the North Atlantic Oscillation are weaker in the North Atlantic and Arctic than in the equatorial region and southern subtropics. Linear trends for 1995 to 2009 indicate increased uptake and generally correspond between methodologies in the North Atlantic, but there is disagreement amongst methodologies in the equatorial region and southern subtropics.

  12. Atlantic and Arctic sea-air CO2 fluxes, 1990-2009

    NASA Astrophysics Data System (ADS)

    Schuster, U.; McKinley, G. A.; Bates, N.; Chevallier, F.; Doney, S. C.; Fay, A. R.; González-Dávila, M.; Gruber, N.; Jones, S.; Krijnen, J.; Landschützer, P.; Lefèvre, N.; Manizza, M.; Mathis, J.; Metzl, N.; Olsen, A.; Rios, A. F.; Rödenbeck, C.; Santana-Casiano, J. M.; Takahashi, T.; Wanninkhof, R.; Watson, A. J.

    2012-08-01

    The Atlantic and Arctic oceans are critical components of the global carbon cycle. Here we quantify the net sea-air CO2 flux, for the first time, across different methodologies for consistent time and space scales, for the Atlantic and Arctic basins. We present the long-term mean, seasonal cycle, interannual variability and trends in sea-air CO2 flux for the period 1990 to 2009, and assign an uncertainty to each. We use regional cuts from global observations and modelling products, specifically a pCO2-based CO2 flux climatology, flux estimates from the inversion of oceanic and atmospheric data, and results from six ocean biogeochemical models. Additionally, we use basin-wide flux estimates from surface ocean pCO2 observations based on two distinct methodologies. Our best estimate of the contemporary sea-to-air flux of CO2 (sum of anthropogenic and natural components) by the Atlantic between 40° S and 79° N is -0.49 ± 0.11 Pg C yr-1 and by the Arctic is -0.12 ± 0.06 Pg C yr-1, leading to a combined sea-to-air flux of -0.61 ± 0.12 Pg C yr-1 for the two decades (negative reflects ocean uptake). We do find broad agreement amongst methodologies with respect to the seasonal cycle in the subtropics of both hemispheres, but not elsewhere. Agreement with respect to detailed signals of interannual variability is poor; and correlations to the North Atlantic Oscillation are weaker in the North Atlantic and Arctic than in the equatorial region and South Subtropics. Linear trends for 1995 to 2009 indicate increased uptake and generally correspond between methodologies in the North Atlantic, but there is disagreement amongst methodologies in the equatorial region and South Subtropics.

  13. Temporal variability of air-sea CO2 exchange in a low-emission estuary

    NASA Astrophysics Data System (ADS)

    Mørk, Eva Thorborg; Sejr, Mikael Kristian; Stæhr, Peter Anton; Sørensen, Lise Lotte

    2016-07-01

    There is the need for further study of whether global estimates of air-sea CO2 exchange in estuarine systems capture the relevant temporal variability and, as such, the temporal variability of bulk parameterized and directly measured CO2 fluxes was investigated in the Danish estuary, Roskilde Fjord. The air-sea CO2 fluxes showed large temporal variability across seasons and between days and that more than 30% of the net CO2 emission in 2013 was a result of two large fall and winter storms. The diurnal variability of ΔpCO2 was up to 400 during summer changing the estuary from a source to a sink of CO2 within the day. Across seasons the system was suggested to change from a sink of atmospheric CO2 during spring to near neutral during summer and later to a source of atmospheric CO2 during fall. Results indicated that Roskilde Fjord was an annual low-emission estuary, with an estimated bulk parameterized release of 3.9 ± 8.7 mol CO2 m-2 y-1 during 2012-2013. It was suggested that the production-respiration balance leading to the low annual emission in Roskilde Fjord, was caused by the shallow depth, long residence time and high water quality in the estuary. In the data analysis the eddy covariance CO2 flux samples were filtered according to the H2Osbnd CO2 cross-sensitivity assessment suggested by Landwehr et al. (2014). This filtering reduced episodes of contradicting directions between measured and bulk parameterized air-sea CO2 exchanges and changed the net air-sea CO2 exchange from an uptake to a release. The CO2 gas transfer velocity was calculated from directly measured CO2 fluxes and ΔpCO2 and agreed to previous observations and parameterizations.

  14. Sea surface temperature variability in southern Okinawa Trough during last 2700 years

    NASA Astrophysics Data System (ADS)

    Wu, Weichao; Tan, Wenbing; Zhou, Liping; Yang, Huan; Xu, Yunping

    2012-07-01

    Most of the temperature reconstructions for the past two millennia are based on proxy data from various sites on land. Here we present a bidecadal resolution record of sea surface temperature (SST) in Southern Okinawa Trough for the past ca. 2700 years by analyzing tetraether lipids of planktonic archaea in the ODP Hole 1202B, a site under the strong influence of Kuroshio Current and East Asian monsoon. The reconstructed SST anomalies generally coincided with previously reported late Holocene climate events, including the Roman Warm Period, Sui-Tang dynasty Warm Period, Medieval Warm Period, Current Warm Period, Dark Age Cold Period and Little Ice Age. However, the Medieval Warm Period usually thought to be a historical analogue for the Current Warm Period has a mean SST of 0.6-0.8°C lower than that of the Roman Warm Period and Sui-Tang dynasty Warm Period. Despite an increase since 1850 AD, the mean SST in the 20th century is still within the range of natural variability during the past 2700 years. A close correlation of SST in Southern Okinawa Trough with air temperature in East China, intensity of East Asian monsoon and the El-Niño Southern Oscillation index has been attributed to the fluctuations in solar output and oceanic-atmospheric circulation.

  15. Productivity and sea surface temperature are correlated with the pelagic larval duration of damselfishes in the Red Sea.

    PubMed

    Robitzch, Vanessa S N; Lozano-Cortés, Diego; Kandler, Nora M; Salas, Eva; Berumen, Michael L

    2016-04-30

    We examined the variation of pelagic larval durations (PLDs) among three damselfishes, Dascyllus aruanus, D. marginatus, and D. trimaculatus, which live under the influence of an environmental gradient in the Red Sea. PLDs were significantly correlated with latitude, sea surface temperature (SST), and primary production (CHLA; chlorophyll a concentrations). We find a consistent decrease in PLDs with increasing SST and primary production (CHLA) towards the southern Red Sea among all species. This trend is likely related to higher food availability and increased metabolic rates in that region. We suggest that food availability is a potentially stronger driver of variation in PLD than temperature, especially in highly oligotrophic regions. Additionally, variations in PLDs were particularly high among specimens of D. marginatus, suggesting a stronger response to local environmental differences for endemic species. We also report the first average PLD for this species over a broad geographic range (19.82±2.92days). PMID:26654297

  16. Controls of air temperature variability over an Alpine Glacier

    NASA Astrophysics Data System (ADS)

    Shaw, Thomas; Brock, Ben; Ayala, Álvaro; Rutter, Nick

    2016-04-01

    Near surface air temperature (Ta) is one of the most important controls on energy exchange between a glacier surface and the overlying atmosphere. However, not enough detail is known about the controls on Ta across a glacier due to sparse data availability. Recent work has provided insights into variability of Ta along glacier centre-lines in different parts of the world, yet there is still a limited understanding of off-centreline variability in Ta and how best to estimate it from distant off-glacier locations. We present a new dataset of distributed 2m Ta records for the Tsanteleina Glacier in Northwest Italy from July-September, 2015. Data provide detailed information of lateral (across-glacier) and centre-line variations in Ta, with ~20,000 hourly observations from 17 locations. The suitability of different vertical temperature gradients (VTGs) in estimating air temperature is considered under a range of meteorological conditions and from different forcing locations. A key finding is that local VTGs account for a lot of Ta variability under a broad range of climatic conditions. However, across-glacier variability is found to be significant, particularly for high ambient temperatures and for localised topographic depressions. The relationship of spatial Ta patterns with regional-scale reanalysis data and alternative Ta estimation methodologies are also presented. This work improves the knowledge of local scale Ta variations and their importance to melt modelling.

  17. High efficiency power generation from coal and wastes utilizing high temperature air combustion technology (Part 2: Thermal performance of compact high temperature air preheater and MEET boiler)

    SciTech Connect

    Iwahashi, Takashi; Kosaka, Hitoshi; Yoshida, Nobuhiro

    1998-07-01

    The compact high temperature air preheater and the MEET boiler, which are critical components of the MEET system, are the direct evolutions of the high temperature air combustion technology. Innovative hardware concept for a compact high temperature air preheater has been proposed, and preliminary experiment using the MEET-I high temperature air preheater based on this concept successfully demonstrated continuous high temperature air generation with almost no temperature fluctuation. A preliminary heat transfer calculation for the MEET boiler showed that regenerative combustion using high temperature air is quite effective for radiative heat transfer augmentation in a boiler, which will lead to significant downsizing of a boiler. The heat transfer characteristics in the MEET boiler were experimentally measured and the heat transfer promotion effect and the uniform heat transfer field were confirmed. Moreover, it was understood that excellent combustion with the low BTU gas of about 3,000 kcal/m{sup 3} was done.

  18. Air-water partitioning of 222Rn and its dependence on water temperature and salinity.

    PubMed

    Schubert, Michael; Paschke, Albrecht; Lieberman, Eric; Burnett, William C

    2012-04-01

    Radon is useful as a tracer of certain geophysical processes in marine and aquatic environments. Recent applications include detection of groundwater discharges into surface waters and assessment of air/sea gas piston velocities. Much of the research performed in the past decade has relied on continuous measurements made in the field using a radon stripping unit connected to a radon-in-air detection system. This approach assumes that chemical equilibrium is attained between the water and gas phases and that the resulting air activity can be multiplied by a partition coefficient to obtain the corresponding radon-in-water activity. We report here the results of a series of laboratory experiments that describes the dependence of the partition coefficient upon both water temperature and salinity. Our results show that the temperature dependence for freshwater closely matches results that were previously available. The salinity effect, however, has largely been ignored and our results show that this can result in an overestimation of radon concentrations, especially in cooler, more saline waters. Related overestimates in typical situations range between 10 (warmer less saline waters) and 20% (cooler, more saline waters). PMID:22385122

  19. Continental and sea surface temperature variability in southeast Africa (Zambezi River region) since MIS 3

    NASA Astrophysics Data System (ADS)

    Castañeda, I. S.; Tjallingii, R.; Wang, Y. V.; Mets, A.; van der Lubbe, J.; Brummer, G.; Sinninghe Damste, J. S.; Schneider, R. R.; Schouten, S.

    2010-12-01

    At present, few paleoclimate records exist from the region of southeast Africa. The continental climate history of southeast Africa is of much interest since this region falls under the influence of both the Intertropical Convergence Zone (ITCZ) and Congo Air Boundary (CAB) and likely experienced considerably different hydrological conditions when glacial conditions prevailed. Likewise, the paleoceanographic history of the Mozambique Channel of the coast of southeast Africa is of much interest since mesoscale eddies (Agulhas rings) formed in this region transport and release warm and saline Indian Ocean waters into the South Atlantic influencing the buoyancy of Atlantic thermocline waters, deep-water formation, and Atlantic Meridional Overturning Circulation. Sea surface temperatures (SST) of the southern Indian Ocean are additionally important for modulating precipitation in southeast Africa. Here, we utilize multiple organic (TEX86, BIT Index, MBT, CBT) and inorganic (XRF core scanning) geochemical proxies on a sediment core collected from near the Zambezi River (core 64PE304-80; -18.24 °S, 37.87 °E) to examine continental conditions within the Zambezi River catchment as well as the SST history of the Mozambique Channel. Throughout the ~38 kyr record of 64PE304-80, variations in the BIT Index, a proxy for marine vs. soil organic matter input, closely track changes in the log (Ca/Ti) ratio, a proxy for marine vs. lithogenic input. These records indicate increased lithogenic/soil OM contributions in the Late Pleistocene portion of the record whereas the Holocene is characterized by increased marine contributions. This pattern likely reflects closer proximity of the Zambezi river mouth and transport of terrestrial material to the coring site during the last glacial sea-level lowstand. A particularly interesting feature of these records is pronounced millennial-scale fluctuations occurring within Marine Isotope Stages (MIS) 2 and 3, which posses a similar structure

  20. Distribution and Sea-to-air Flux of Nitrous Oxide in the East China Sea during the Summer of 2013

    NASA Astrophysics Data System (ADS)

    Wang, Lan; Zhang, Guiling; Zhu, Zhuoyi; Li, Jia; Liu, Sumei; Ye, Wangwang; Han, Yu

    2016-07-01

    Dissolved nitrous oxide (N2O) at different depths of 73 stations in the Changjiang (Yangtze River) Estuary and the East China Sea (ECS) were determined from August 4 to 31 of 2013, and the sea-to-air fluxes of N2O were also estimated in this study. N2O concentrations in the surface waters ranged from 6.33 to 44.40 nmol L-1 with an average of (9.27±4.30) nmol L-1 and the values in the bottom waters ranged from 5.19 to 26.98 nmol L-1 with an average of (11.87±3.71) nmol L-1. The concentrations of N2O decreased with distance from the Changjiang Estuary to the open sea. The vertical distributions of N2O indicated great spatial variations. A region of significant bottom-water hypoxia, with oxygen concentration less than 1.5 mg L-1, occurred at the north of the ECS, and increased bottom N2O concentrations was observed. Frequent vertical mixing may enhance the emission of N2O from this hypoxic area. N2O in the surface waters of all stations were over-saturated, and the N2O saturations ranged from 106% to 658%, with an average of (149±62)%. We estimated the sea-to-air fluxes of N2O as (30.6±59.1) μmol m-2 d-1 from the Changjiang Estuary, (9.8±8.8) μmol m-2 d-1 from the coastal and shelf, and (21.0±12.7) μmol m-2 d-1 from the continental slope using the Wanninkhof 1992 equation, (24.9±47.2) μmol m-2 d-1, (8.0±6.7) μmol m-2 d-1 and (16.5±9.6) μmol m-2 d-1 using the Nightingale 2000 equation, respectively. N2O emission from the ECS was estimated to be about (8.2-16.0)×10-2 Tg-N2O yr-1, suggesting that the ECS was a significant net source of atmospheric N2O.

  1. Direct measurements of air-sea CO2 exchange over a coral reef

    NASA Astrophysics Data System (ADS)

    McGowan, Hamish A.; MacKellar, Mellissa C.; Gray, Michael A.

    2016-05-01

    Quantification of CO2 exchange with the atmosphere over coral reefs has relied on microscale measurements of pCO2 gradients across the air-sea interfacial boundary; shipboard measurements of air-sea CO2 exchange over adjacent ocean inferred to represent over reef processes or ecosystem productivity modeling. Here we present by way of case study the first direct measurements of air-sea CO2 exchange over a coral reef made using the eddy covariance method. Research was conducted during the summer monsoon over a lagoonal platform reef in the southern Great Barrier Reef, Australia. Results show the reef flat to be a net source of CO2 to the atmosphere of similar magnitude as coastal lakes, while adjacent shallow and deep lagoons were net sinks as was the surrounding ocean. This heterogeneity in CO2 exchange with the atmosphere confirms need for spatially representative direct measurements of CO2 over coral reefs to accurately quantify their role in atmospheric carbon budgets.

  2. Observations of Seasonal Variations in Sea Bottom Temperature and Salinity in Bykovsky Bay in the Laptev Sea

    NASA Astrophysics Data System (ADS)

    Overduin, P. P.; Grigoriev, M. N.; Kopsch, C.

    2009-04-01

    Following inundation due to coastal erosion or increasing relative sea level, flooded permafrost is separated from the atmosphere by sea ice and water. The boundary condition for further permafrost evolution is given by seabed salinity and temperature. Few records of seasonal variations in these parameters exist, limiting our ability to predict the speed of subsea peramfrost degradation, or to correlate borehole observations with near-shore processes. For subsea permafrost, seabottom temperature drives sediment warming and variations in salinity can increase the rate of penetration of the seawater salt front into the sediment. A borehole transect drilled in 1983 in the nearshore zone off Mamontovy Khayata on the Bykovsky Peninsula in the Laptev Sea resulted in a description of subsea sediment temperature and the inclination of the top of the ice-bearing permafrost perpendicular to the coast out to a distance of 3 km. Before erosion, the landscape at Mamontovy Khayata is composed of ice-rich periglacial deposits down to and beneath current sea level, most of which are removed during erosion. Thermokarst features dominate the landscape and affect coastal bluff height and the resilience of sediments to coastal erosion and abrasion. We installed dataloggers on the seabed in 2007 to measure bottom water temperature and salinity at hourly intervals. Temperature variations are higher than expected, and together with salinity demonstrate the changing seasonal importance of warm, fresh river water and colder, saltier sea water that has been observed elsewhere. During winter, bottom water temperatures stabilize at the freezing point, but rise slowly during the winter, during a period of increasing salinity. We propose that this warming corresponds to the loss of heat from the underlying sediment. We compare integrated rates of warming of subsea and terrestrial permafrost and estimate the increase in the rate of subsea permafrost thermal degradation after inundation.

  3. Sea surface temperature of the coastal zones of France

    NASA Technical Reports Server (NTRS)

    Deschamps, P. Y.; Crepon, M.; Monget, J. M.; Verger, F. (Principal Investigator); Frouin, R.; Cassanet, J.; Wald, L.

    1980-01-01

    The various thermal gradients in the coastal zones of France were mapped with regard to natural phenomena and man made thermal effluents. The mesoscale thermal features of the English Channel, the Bay of Biscay, and the northwestern Mediterranean Sea were also studied. The evolution of the thermal gradients generated by the main estuaries of the French coastal zones was investigated along with the modeling of diurnal heating of the sea surface and its influence on the oceanic surface layers.

  4. Air Temperature estimation from Land Surface temperature and solar Radiation parameters

    NASA Astrophysics Data System (ADS)

    Lazzarini, Michele; Eissa, Yehia; Marpu, Prashanth; Ghedira, Hosni

    2013-04-01

    Air Temperature (AirT) is a fundamental parameter in a wide range of applications such as climate change studies, weather forecast, energy balance modeling, efficiency of Photovoltaic (PV) solar cells, etc. Air temperature data are generally obtained through regular measurements from meteorological stations. The distribution of these stations is normally sparse, so the spatial pattern of this parameter cannot be accurately estimated by interpolation methods. This work investigated the relationship between Air Temperature measured at meteorological stations and spatially contiguous measurements derived from Remote Sensing techniques, such as Land Surface Temperature (LST) maps, emissivity maps and shortwave radiation maps with the aim of creating a continuous map of AirT. For LST and emissivity, MSG-SEVIRI LST product from Land Surface Analysis Satellite Applications Facility (LSA-SAF) has been used. For shortwave radiation maps, an Artificial Neural Networks ensemble model has been developed and previously tested to create continuous maps from Global Horizontal Irradiance (GHI) point measurements, utilizing six thermal channels of MSG-SEVIRI. The testing sites corresponded to three meteorological stations located in the United Arab Emirates (UAE), where in situ measurements of Air Temperature were available. From the starting parameters, energy fluxes and net radiation have been calculated, in order to have information on the incoming and outgoing long-wave radiation and the incoming short-wave radiation. The preliminary analysis (day and Night measurements, cloud free) showed a strong negative correlation (0.92) between Outgoing long-wave radiation - GHI and LST- AirT, with a RMSE of 1.84 K in the AirT estimation from the initial parameters. Regression coefficients have been determined and tested on all the ground stations. The analysis also demonstrated the predominant impact of the incoming short-wave radiation in the AirT hourly variation, while the incoming

  5. Sensitivity of New England Stream Temperatures to Air Temperature and Precipitation Under Projected Climate

    NASA Astrophysics Data System (ADS)

    Huang, T.; Samal, N. R.; Wollheim, W. M.; Stewart, R. J.; Zuidema, S.; Prousevitch, A.; Glidden, S.

    2015-12-01

    The thermal response of streams and rivers to changing climate will influence aquatic habitat. This study examines the impact that changing climate has on stream temperatures in the Merrimack River, NH/MA USA using the Framework for Aquatic Modeling in the Earth System (FrAMES), a spatially distributed river network model driven by air temperature, air humidity, wind speed, precipitation, and solar radiation. Streamflow and water temperatures are simulated at a 45-second (latitude x longitude) river grid resolution for 135 years under historical and projected climate variability. Contemporary streamflow (Nash-Sutcliffe Coefficient = 0.77) and river temperatures (Nash-Sutcliffe Coefficient = 0.89) matched at downstream USGS gauge data well. A suite of model runs were made in combination with uniformly increased daily summer air temperatures by 2oC, 4 oC and 6 oC as well as adjusted precipitation by -40%, -30%, -20%, -10% and +10% as a sensitivity analysis to explore a broad range of potential future climates. We analyzed the summer stream temperatures and the percent of river length unsuitable for cold to warm water fish habitats. Impacts are greatest in large rivers due to the accumulation of river temperature warming throughout the entire river network. Cold water fish (i.e. brook trout) are most strongly affected while, warm water fish (i.e. largemouth bass) aren't expected to be impacted. The changes in stream temperatures under various potential climate scenarios will provide a better understanding of the specific impact that air temperature and precipitation have on aquatic thermal regimes and habitat.

  6. On extreme rainfall intensity increases with air temperature

    NASA Astrophysics Data System (ADS)

    Molnar, Peter; Fatichi, Simone; Paschalis, Athanasios; Gaal, Ladislav; Szolgay, Jan; Burlando, Paolo

    2016-04-01

    The water vapour holding capacity of air increases at about 7% per degree C according to the Clausius-Clapeyron (CC) relation. This is one of the arguments why a warmer future atmosphere, being able to hold more moisture, will generate higher extreme precipitation intensities. However, several empirical studies have recently demonstrated an increase in extreme rain intensities with air temperature above CC rates, in the range 7-14% per degree C worldwide (called super-CC rates). This was observed especially for shorter duration rainfall, i.e. in hourly and finer resolution data (e.g. review in Westra et al., 2014). The super-CC rate was attributed to positive feedbacks between water vapour and the updraft dynamics in convective clouds and lateral supply (convergence) of moisture. In addition, mixing of storm types was shown to be potentially responsible for super-CC rates in empirical studies. Assuming that convective events are accompanied by lightning, we will show on a large rainfall dataset in Switzerland (30 year records of 10-min and 1-hr data from 59 stations) that while the average rate of increase in extreme rainfall intensity (95th percentile) is 6-7% in no-lightning events and 8-9% in lightning events, it is 11-13% per degree C when all events are combined (Molnar et al., 2015). These results are relevant for climate change studies which predict shifts in storm types in a warmer climate in some parts of the world. The observation that extreme rain intensity and air temperature are positively correlated has consequences for the stochastic modelling of rainfall. Most current stochastic models do not explicitly include a direct rain intensity-air temperature dependency beyond applying factors of change predicted by climate models to basic statistics of precipitation. Including this dependency explicitly in stochastic models will allow, for example in the nested modelling approach of Paschalis et al. (2014), the random cascade disaggregation routine to be

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  8. Sensitivity of the air-sea CO2 exchange in the Baltic Sea and Danish inner waters to atmospheric short-term variability

    NASA Astrophysics Data System (ADS)

    Lansø, A. S.; Bendtsen, J.; Christensen, J. H.; Sørensen, L. L.; Chen, H.; Meijer, H. A. J.; Geels, C.

    2015-05-01

    Minimising the uncertainties in estimates of air-sea CO2 exchange is an important step toward increasing the confidence in assessments of the CO2 cycle. Using an atmospheric transport model makes it possible to investigate the direct impact of atmospheric parameters on the air-sea CO2 flux along with its sensitivity to, for example, short-term temporal variability in wind speed, atmospheric mixing height and atmospheric CO2 concentration. With this study, the importance of high spatiotemporal resolution of atmospheric parameters for the air-sea CO2 flux is assessed for six sub-basins within the Baltic Sea and Danish inner waters. A new climatology of surface water partial pressure of CO2 (pCO2w) has been developed for this coastal area based on available data from monitoring stations and on-board pCO2w measuring systems. Parameterisations depending on wind speed were applied for the transfer velocity to calculate the air-sea CO2 flux. Two model simulations were conducted - one including short-term variability in atmospheric CO2 (VAT), and one where it was not included (CAT). A seasonal cycle in the air-sea CO2 flux was found for both simulations for all sub-basins with uptake of CO2 in summer and release of CO2 to the atmosphere in winter. During the simulated period 2005-2010, the average annual net uptake of atmospheric CO2 for the Baltic Sea, Danish straits and Kattegat was 287 and 471 Gg C yr-1 for the VAT and CAT simulations, respectively. The obtained difference of 184 Gg C yr-1 was found to be significant, and thus ignoring short-term variability in atmospheric CO2 does have a sizeable effect on the air-sea CO2 exchange. The combination of the atmospheric model and the new pCO2w fields has also made it possible to make an estimate of the marine part of the Danish CO2 budget for the first time. A net annual uptake of 2613 Gg C yr-1 was found for the Danish waters. A large uncertainty is connected to the air-sea CO2 flux in particular caused by the transfer

  9. Sensitivity of the air-sea CO2 exchange in the Baltic Sea and Danish inner waters to atmospheric short term variability

    NASA Astrophysics Data System (ADS)

    Lansø, A. S.; Bendtsen, J.; Christensen, J. H.; Sørensen, L. L.; Chen, H.; Meijer, H. A. J.; Geels, C.

    2014-12-01

    Minimising the uncertainties in estimates of air-sea CO2 exchange is an important step toward increasing the confidence in assessments of the CO2 cycle. Using an atmospheric transport model makes it possible to investigate the direct impact of atmospheric parameters on the air-sea CO2 flux along with its sensitivity to e.g. short-term temporal variability in wind speed, atmospheric mixing height and the atmospheric CO2 concentration. With this study the importance of high spatiotemporal resolution of atmospheric parameters for the air-sea CO2 flux is assessed for six sub-basins within the Baltic Sea and Danish inner waters. A new climatology of surface water partial pressure of CO2 (pCO2) has been developed for this coastal area based on available data from monitoring stations and underway pCO2 measuring systems. Parameterisations depending on wind speed were applied for the transfer velocity to calculate the air-sea CO2 flux. Two model simulations were conducted - one including short term variability in atmospheric CO2 (VAT), and one where it was not included (CAT). A seasonal cycle in the air-sea CO2 flux was found for both simulations for all sub-basins with uptake of CO2 in summer and release of CO2 to the atmosphere in winter. During the simulated period 2005-2010 the average annual net uptake of atmospheric CO2 for the Baltic Sea, Danish Straits and Kattegat was 287 and 471 Gg C yr-1 for the VAT and CAT simulations, respectively. The obtained difference of 184 Gg C yr-1 was found to be significant, and thus ignoring short term variability in atmospheric CO2 does have a sizeable effect on the air-sea CO2 exchange. The combination of the atmospheric model and the new pCO2 fields has also made it possible to make an estimate of the marine part of the Danish CO2 budget for the first time. A net annual uptake of 2613 Gg C yr-1 was found for the Danish waters. A large uncertainty is connected to the air-sea CO2 flux in particular caused by the transfer velocity

  10. MP3 - A Meteorology and Physical Properties Package for Titan Air-Sea Studies

    NASA Astrophysics Data System (ADS)

    Lorenz, R. D.; Stofan, E.; Lunine, J. I.; Zarnecki, J. C.; Harri, A.-M.; Karkoschka, E.; Newman, C. E.; Bierhaus, E. B.; Clark, B. C.; Yelland, M.; Leese, M. R.; Boldt, J.; Darlington, E.; Neish, C. D.; Sotzen, K.; Arvelo, J.; Rasbach, C.; Kretsch, W.; Strohbehn, K.; Grey, M.; Mann, J.; Zimmerman, H.; Reed, C.

    2012-10-01

    MP3 is a sensor suite for the proposed Titan Mare Explorer (TiME) Discovery mission to Ligeia Mare. MP3 will measure temperatures, and wind velocity, methane humidity, and pressure, as well as sea turbidity, dielectric properties, and depth via sonar.

  11. Effect of Air-Sea coupling on the Frequency Distribution of Intense Tropical Cyclones over the Northwestern Pacific

    NASA Astrophysics Data System (ADS)

    Ogata, Tomomichi; Mizuta, Ryo; Adachi, Yukimasa; Murakami, Hiroyuki; Ose, Tomomaki

    2016-04-01

    Effect of air-sea coupling on the frequency distribution of intense tropical cyclones (TCs) over the northwestern Pacific (NWP) region is investigated using an atmosphere and ocean coupled general circulation model (AOGCM). Monthly varying flux adjustment enables AOGCM to simulate both subseasonal air-sea interaction and realistic seasonal to interannual SST variability. The maximum of intense TC distribution around 20-30°N in the AGCM shifts equatorward in the AOGCM due to the air-sea coupling. Hence AOGCM reduces northward intense TC distribution bias seen in AGCM. Over the NWP, AOGCM-simulated SST variability is large around 20-30°N where the warm mixed layer becomes shallower rapidly. Active entrainment from subsurface water over this region causes stronger SST cooling and hence TC intensity decreases. These results suggest that air-sea coupling characterized by subsurface oceanic condition causes more realistic distribution of intense TCs over the NWP.

  12. Subpolar gyre and radiative forcings moderate sea surface temperatures of the Norwegian Sea during the mid-Piacenzian

    NASA Astrophysics Data System (ADS)

    Bachem, Paul; Risebrobakken, Bjørg; McClymont, Erin

    2016-04-01

    The mid-Piacenzian age (ca. 3.3-3.0 Ma) of the Pliocene epoch has been proposed as a possible reference for future warm climate states. We have developed a new set of orbital-resolution alkenone-based sea surface temperature (SST) and ice rafted debris (IRD) records from the Norwegian Sea. SSTs in the Norwegian Sea were 2-3°C warmer in the mid-Piacenzian compared to the Holocene average. There is notable orbital-scale SST variability with a range of 4°C. The most likely cause of the average long-term warmth is a higher atmospheric CO2 concentration. A correlation of SST variability with the presence of Greenland-sourced IRD suggests a common climate forcing acting across the Nordic Seas region. The orbital-scale variability was in part caused by interplay of obliquity and precession, as low SSTs coincide with times of low northern summer insolation. Changes of the SST gradient between the Norwegian Sea and North Atlantic sites suggest that the subpolar gyre was at least of comparable strength as during the Holocene. The North Atlantic Current (NAC) influence on the Norwegian Sea SSTs does not appear to have been stronger than during the Holocene.

  13. Observations of Cooling Summer Daytime Temperatures (1948-2005) in Growing Urban Coastal California Air Basins

    NASA Astrophysics Data System (ADS)

    Bornstein, R.; Lebassi, B.; Gonzalez, J.

    2008-12-01

    The study evaluated long-term (1948-2005) air temperatures in California (CA) during summer (June- August). The aggregate CA results showed asymmetric warming, as daily minimum temperatures increased faster than daily maximum temperatures. The spatial distributions of daily maximum temperatures in the heavily urbanized South Coast and San Francisco Bay Area air basins, however, exhibited a complex pattern, with cooling at low-elevation (mainly urban) coastal-areas and warming at (mainly rural) inland areas. Previous studies have suggested that cooling summer max temperatures in CA were due to increased irrigation, coastal upwelling, or cloud cover. The current hypothesis, however, is that this temperature pattern arises from a 'reverse-reaction' to greenhouse gas (GHG) induced global-warming. In this hypothesis, the global warming of inland areas resulted in an increased (cooling) sea breeze activity in coastal areas. The coastal cooling thus resulted as urban heat island (UHI) warming was weaker than the reverse-reaction cooling; if there was no UHI effect, then the cooling would be even stronger. The cooling or warming trends at several pairs of nearby urban and non- urban sites were compared in an effort to separate out the urban heat island (UHI) and global warming components of the trend. Average temperatures from global circulation models show warming that decreases from inland areas of California to its coastal areas. Such large scale models, however, cannot resolve these smaller scale topographic and coastal effects. Meso-scale modeling on a 4 km grid is thus being carried out to evaluate the contributions from GHG global-warming and land-use changes, including UHI development, to the observed trends. Significant societal impacts may result from this observed reverse-reaction to GHG- warming; possible beneficial effects include decreased maximum: O3 levels, human thermal-stress, and per- capita energy requirements for cooling.

  14. Air breathing in the Arctic: influence of temperature, hypoxia, activity and restricted air access on respiratory physiology of the Alaska blackfish Dallia pectoralis

    PubMed Central

    Lefevre, Sjannie; Damsgaard, Christian; Pascale, Desirae R.; Nilsson, Göran E.; Stecyk, Jonathan A. W.

    2014-01-01

    The Alaska blackfish (Dallia pectoralis) is an air-breathing fish native to Alaska and the Bering Sea islands, where it inhabits lakes that are ice-covered in the winter, but enters warm and hypoxic waters in the summer to forage and reproduce. To understand the respiratory physiology of this species under these conditions and the selective pressures that maintain the ability to breathe air, we acclimated fish to 5°C and 15°C and used respirometry to measure: standard oxygen uptake () in normoxia (19.8 kPa PO2) and hypoxia (2.5 kPa), with and without access to air; partitioning of standard in normoxia and hypoxia; maximum and partitioning after exercise; and critical oxygen tension (Pcrit). Additionally, the effects of temperature acclimation on haematocrit, haemoglobin oxygen affinity and gill morphology were assessed. Standard was higher, but air breathing was not increased, at 15°C or after exercise at both temperatures. Fish acclimated to 5°C or 15°C increased air breathing to compensate and fully maintain standard in hypoxia. Fish were able to maintain through aquatic respiration when air was denied in normoxia, but when air was denied in hypoxia, standard was reduced by ∼30–50%. Pcrit was relatively high (5 kPa) and there were no differences in Pcrit, gill morphology, haematocrit or haemoglobin oxygen affinity at the two temperatures. Therefore, Alaska blackfish depends on air breathing in hypoxia and additional mechanisms must thus be utilised to survive hypoxic submergence during the winter, such as hypoxia-induced enhancement in the capacities for carrying and binding blood oxygen, behavioural avoidance of hypoxia and suppression of metabolic rate. PMID:25394628

  15. Generation of low-temperature air plasma for food processing

    NASA Astrophysics Data System (ADS)

    Stepanova, Olga; Demidova, Maria; Astafiev, Alexander; Pinchuk, Mikhail; Balkir, Pinar; Turantas, Fulya

    2015-11-01

    The project is aimed at developing a physical and technical foundation of generating plasma with low gas temperature at atmospheric pressure for food industry needs. As known, plasma has an antimicrobial effect on the numerous types of microorganisms, including those that cause food spoilage. In this work an original experimental setup has been developed for the treatment of different foods. It is based on initiating corona or dielectric-barrier discharge in a chamber filled with ambient air in combination with a certain helium admixture. The experimental setup provides various conditions of discharge generation (including discharge gap geometry, supply voltage, velocity of gas flow, content of helium admixture in air and working pressure) and allows for the measurement of the electrical discharge parameters. Some recommendations on choosing optimal conditions of discharge generation for experiments on plasma food processing are developed.

  16. The Trends of Soil Temperature Change Associated with Air Temperature Change in Korea from 1973 to 2012

    NASA Astrophysics Data System (ADS)

    Lee, Bo-Hyun; Park, Byeong-Hak; Koh, Eun-Hee; Lee, Kang-Kun

    2015-04-01

    Examining long-term trends of the soil temperature can contribute to assessing subsurface thermal environment. The recent 40-year (1973-2012) meteorological data from 14 Korea Meteorological Administration (KMA) stations was analyzed in this study to estimate the temporal variations of air and soil temperatures (at depths 0.5 and 1.0m) in Korea and their relations. The information on regional characteristics of study sites was also collected to investigate the local and regional features influencing the soil temperature. The long-term increasing trends of both air and soil temperatures were estimated by using simple linear regression analysis. The air temperature rise and soil temperature rise were compared for every site to reveal the relation between air and soil temperature changes. In most sites, the proportion of soil temperature rise to air temperature rise was nearly one to one except a few sites. The difference between the air and soil temperature trends at those sites may be attributed to the combined effect of soil properties such as thermal diffusivity and soil moisture content. The impact of urbanization on the air and soil temperature was also investigated in this study. Establishment of the relationship between the air and soil temperatures can help predicting the soil temperature change in a region where no soil temperature data is obtained by using air temperature data. For rigorous establishment of the relationship between soil and air temperatures, more thorough investigation on the soil thermal properties is necessary through additional monitoring and accompanied validation of the proposed relations. Keywords : Soil temperature, Air temperature, Cross-correlation analysis, Soil thermal diffusivity, Urbanization effect Acknowledgement This work was supported by the research project of "Advanced Technology for Groundwater Development and Application in Riversides (Geowater+)" in "Water Resources Management Program (code 11 Technology Innovation C05

  17. Sea-air CO2 fluxes in the Southern Ocean for the period 1990-2009

    NASA Astrophysics Data System (ADS)

    Lenton, A.; Tilbrook, B.; Law, R.; Bakker, D.; Doney, S. C.; Gruber, N.; Hoppema, M.; Ishii, M.; Lovenduski, N. S.; Matear, R. J.; McNeil, B. I.; Metzl, N.; Mikaloff Fletcher, S. E.; Monteiro, P.; Rödenbeck, C.; Sweeney, C.; Takahashi, T.

    2013-01-01

    The Southern Ocean (44° S-75° S) plays a critical role in the global carbon cycle, yet remains one of the most poorly sampled ocean regions. Different approaches have been used to estimate sea-air CO2 fluxes in this region: synthesis of surface ocean observations, ocean biogeochemical models, and atmospheric and ocean inversions. As part of the RECCAP (REgional Carbon Cycle Assessment and Processes) project, we combine these different approaches to quantify and assess the magnitude and variability in Southern Ocean sea-air CO2 fluxes between 1990-2009. Using all models and inversions (26), the integrated median annual sea-air CO2 flux of -0.42 ± 0.07 Pg C yr-1 for the 44° S-75° S region is consistent with the -0.27 ± 0.13 Pg C yr-1 calculated using surface observations. The circumpolar region south of 58° S has a small net annual flux (model and inversion median: -0.04 ± 0.07 Pg C yr-1 and observations: +0.04 ± 0.02 Pg C yr-1), with most of the net annual flux located in the 44° S to 58° S circumpolar band (model and inversion median: -0.36 ± 0.09 Pg C yr-1 and observations: -0.35 ± 0.09 Pg C yr-1). Seasonally, in the 44° S-58° S region, the median of 5 ocean biogeochemical models captures the observed sea-air CO2 flux seasonal cycle, while the median of 11 atmospheric inversions shows little seasonal change in the net flux. South of 58° S, neither atmospheric inversions nor ocean biogeochemical models reproduce the phase and amplitude of the observed seasonal sea-air CO2 flux, particularly in the Austral Winter. Importantly, no individual atmospheric inversion or ocean biogeochemical model is capable of reproducing both the observed annual mean uptake and the observed seasonal cycle. This raises concerns about projecting future changes in Southern Ocean CO2 fluxes. The median interannual variability from atmospheric inversions and ocean biogeochemical models is substantial in the Southern Ocean; up to 25% of the annual mean flux with 25% of this

  18. Reconstructing Variations of Global Sea-Surface Temperature during the Last Interglaciation

    NASA Astrophysics Data System (ADS)

    Hoffman, J. S.; Clark, P. U.; He, F.; Parnell, A. C.

    2015-12-01

    The last interglaciation (LIG; ~130-116 ka) was the most recent period in Earth history with higher-than-present global sea level (≥6 m) under similar-to-preindustrial concentrations of atmospheric CO2, suggesting additional feedbacks related to albedo, insolation, and ocean circulation in generating the apparent climatic differences between the LIG and present Holocene. However, our understanding of how much warmer the LIG sea surface was relative to the present interglaciation remains uncertain, with current estimates suggesting from 0°C to 2°C warmer than late-20thcentury average global temperatures. Moreover, the timing, spatial expression, and amplitude of regional and global sea surface temperature variability related to other climate forcing during the LIG are poorly constrained, largely due to uncertainties in age control and proxy temperature reconstructions. An accurate characterization of global and regional temperature change during the LIG can serve as a benchmark for paleoclimate modeling intercomparison projects and help improve understanding of sea-level sensitivity to temperature change. We will present a global compilation (~100 published records) of sea surface temperature (SST) and other climate reconstructions spanning the LIG. Using a Monte Carlo-enabled cross-correlation maximization algorithm to climatostratigraphically align proxy records and then account for both the resulting chronologic and proxy calibration uncertainties with Bayesian statistical inference, our results quantify the spatial timing, amplitude, and uncertainty in estimates of global and regional sea surface temperature change during the LIG and its relation to potential forcings.

  19. Sea Surface Temperature Influence on Terrestrial Gross Primary Production along the Southern California Current.

    PubMed

    Reimer, Janet J; Vargas, Rodrigo; Rivas, David; Gaxiola-Castro, Gilberto; Hernandez-Ayon, J Martin; Lara-Lara, Ruben

    2015-01-01

    Some land and ocean processes are related through connections (and synoptic-scale teleconnections) to the atmosphere. Synoptic-scale atmospheric (El Niño/Southern Oscillation [ENSO], Pacific Decadal Oscillation [PDO], and North Atlantic Oscillation [NAO]) decadal cycles are known to influence the global terrestrial carbon cycle. Potentially, smaller scale land-ocean connections influenced by coastal upwelling (changes in sea surface temperature) may be important for local-to-regional water-limited ecosystems where plants may benefit from air moisture transported from the ocean to terrestrial ecosystems. Here we use satellite-derived observations to test potential connections between changes in sea surface temperature (SST) in regions with strong coastal upwelling and terrestrial gross primary production (GPP) across the Baja California Peninsula. This region is characterized by an arid/semiarid climate along the southern California Current. We found that SST was correlated with the fraction of photosynthetic active radiation (fPAR; as a proxy for GPP) with lags ranging from 0 to 5 months. In contrast ENSO was not as strongly related with fPAR as SST in these coastal ecosystems. Our results show the importance of local-scale changes in SST during upwelling events, to explain the variability in GPP in coastal, water-limited ecosystems. The response of GPP to SST was spatially-dependent: colder SST in the northern areas increased GPP (likely by influencing fog formation), while warmer SST at the southern areas was associated to higher GPP (as SST is in phase with precipitation patterns). Interannual trends in fPAR are also spatially variable along the Baja California Peninsula with increasing secular trends in subtropical regions, decreasing trends in the most arid region, and no trend in the semi-arid regions. These findings suggest that studies and ecosystem process based models should consider the lateral influence of local-scale ocean processes that could

  20. Sea Surface Temperature Influence on Terrestrial Gross Primary Production along the Southern California Current

    PubMed Central

    Reimer, Janet J.; Vargas, Rodrigo; Rivas, David; Gaxiola-Castro, Gilberto; Hernandez-Ayon, J. Martin; Lara-Lara, Ruben

    2015-01-01

    Some land and ocean processes are related through connections (and synoptic-scale teleconnections) to the atmosphere. Synoptic-scale atmospheric (El Niño/Southern Oscillation [ENSO], Pacific Decadal Oscillation [PDO], and North Atlantic Oscillation [NAO]) decadal cycles are known to influence the global terrestrial carbon cycle. Potentially, smaller scale land-ocean connections influenced by coastal upwelling (changes in sea surface temperature) may be important for local-to-regional water-limited ecosystems where plants may benefit from air moisture transported from the ocean to terrestrial ecosystems. Here we use satellite-derived observations to test potential connections between changes in sea surface temperature (SST) in regions with strong coastal upwelling and terrestrial gross primary production (GPP) across the Baja California Peninsula. This region is characterized by an arid/semiarid climate along the southern California Current. We found that SST was correlated with the fraction of photosynthetic active radiation (fPAR; as a proxy for GPP) with lags ranging from 0 to 5 months. In contrast ENSO was not as strongly related with fPAR as SST in these coastal ecosystems. Our results show the importance of local-scale changes in SST during upwelling events, to explain the variability in GPP in coastal, water-limited ecosystems. The response of GPP to SST was spatially-dependent: colder SST in the northern areas increased GPP (likely by influencing fog formation), while warmer SST at the southern areas was associated to higher GPP (as SST is in phase with precipitation patterns). Interannual trends in fPAR are also spatially variable along the Baja California Peninsula with increasing secular trends in subtropical regions, decreasing trends in the most arid region, and no trend in the semi-arid regions. These findings suggest that studies and ecosystem process based models should consider the lateral influence of local-scale ocean processes that could

  1. Regional studies using sea surface temperature fields derived from satellite infrared measurements

    NASA Technical Reports Server (NTRS)

    Strong, A. E.

    1972-01-01

    Three examples of sea surface temperature distributions over the western Atlantic are presented. These were detected by means of data from the scanning radiometer on the Improved Tiros Operational Satellite 1 (ITOS 1) under relatively clear sky conditions.

  2. Moderate-Resolution Sea Surface Temperature Data for the Nearshore North Pacific

    EPA Science Inventory

    Coastal sea surface temperature (SST) is an important environmental characteristic defining habitat suitability for nearshore marine and estuarine organisms. The purpose of this publication is to provide access to an easy-to-use coastal SST dataset for ecologists, biogeographers...

  3. Moderate-resolution sea surface temperature data for the Arctic Ocean Ecoregions

    EPA Science Inventory

    Sea surface temperature (SST) is an important environmental characteristic in determining the suitability and sustainability of habitats for marine organisms. Of particular interest is the fate of the Arctic Ocean, which provides critical habitat to commercially important fish (M...

  4. Last Glacial Maximum sea surface temperature and sea-ice extent in the Pacific sector of the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Benz, Verena; Esper, Oliver; Gersonde, Rainer; Lamy, Frank; Tiedemann, Ralf

    2016-08-01

    Sea surface temperatures and sea-ice extent are most critical variables to evaluate the Southern Ocean paleoceanographic evolution in relation to the development of the global carbon cycle, atmospheric CO2 and ocean-atmosphere circulation. Here we present diatom transfer function-based summer sea surface temperature (SSST) and winter sea-ice (WSI) estimates from the Pacific sector of the Southern Ocean to bridge a gap in information that has to date hampered a well-established reconstruction of the last glacial Southern Ocean at circum-Antarctic scale. We studied the Last Glacial Maximum (LGM) at the EPILOG time slice (19,000-23,000 calendar years before present) in 17 cores and consolidated our LGM picture of the Pacific sector taking into account published data from its warmer regions. Our data display a distinct east-west differentiation with a rather stable WSI edge north of the Pacific-Antarctic Ridge in the Ross Sea sector and a more variable WSI extent over the Amundsen Abyssal Plain. The zone of maximum cooling (>4 K) during the LGM is in the present Subantarctic Zone and bounded to its south by the 4 °C isotherm. The isotherm is in the SSST range prevailing at the modern Antarctic Polar Front, representing a circum-Antarctic feature, and marks the northern edge of the glacial Antarctic Circumpolar Current (ACC). The northward deflection of colder than modern surface waters along the South American continent led to a significant cooling of the glacial Humboldt Current surface waters (4-8 K), which affected the temperature regimes as far north as tropical latitudes. The glacial reduction of ACC temperatures may also have resulted in significant cooling in the Atlantic and Indian Southern Ocean, thus enhancing thermal differentiation of the Southern Ocean and Antarctic continental cooling. The comparison with numerical temperature and sea-ice simulations yields discrepancies, especially concerning the estimates of the sea-ice fields, but some simulations

  5. Improving Streamflow Forecasts Using Predefined Sea Surface Temperature

    NASA Astrophysics Data System (ADS)

    Kalra, A.; Ahmad, S.

    2011-12-01

    With the increasing evidence of climate variability, water resources managers in the western United States are faced with greater challenges of developing long range streamflow forecast. This is further aggravated by the increases in climate extremes such as floods and drought caused by climate variability. Over the years, climatologists have identified several modes of climatic variability and their relationship with streamflow. These climate modes have the potential of being used as predictor in models for improving the streamflow lead time. With this as the motivation, the current research focuses on increasing the streamflow lead time using predefine climate indices. A data driven model i.e. Support Vector Machine (SVM) based on the statistical learning theory is used to predict annual streamflow volume 3-year in advance. The SVM model is a learning system that uses a hypothesis space of linear functions in a Kernel induced higher dimensional feature space, and is trained with a learning algorithm from the optimization theory. Annual oceanic-atmospheric indices, comprising of Pacific Decadal Oscillation (PDO), North Atlantic Oscillation (NAO), Atlantic Multidecadal Oscillation (AMO), El Niño-Southern Oscillations (ENSO), and a new Sea Surface Temperature (SST) data set of "Hondo" Region for a period of 1906-2005 are used to generate annual streamflow volumes. The SVM model is applied to three gages i.e. Cisco, Green River, and Lees Ferry in the Upper Colorado River Basin in the western United States. Based on the performance measures the model shows very good forecasts, and the forecast are in good agreement with measured streamflow volumes. Previous research has identified NAO and ENSO as main drivers for extending streamflow forecast lead-time in the UCRB. Inclusion of "Hondo Region" SST information further improve the model's forecasting ability. The overall results of this study revealed that the annual streamflow of the UCRB is significantly influenced by

  6. A simulation of the Southern North Sea in comparison with measurements from the North Sea Project. Part 1: Temperature

    NASA Astrophysics Data System (ADS)

    Holt, Jason T.; James, Ian D.

    1999-06-01

    The accurate simulation of the annual cycle and vertical structure of temperature is crucial to biological and water quality modelling in shelf-seas. As a precursor to these applications, we present a three-dimensional baroclinic simulation of the southern North Sea at the time of the North Sea Project (NSP), with density controlled by a prognostically evolving temperature field forced by surface heat fluxes from bulk formulae. The model results are compared, on a point for point basis, with CTD data from the NSP. The annual cycles in mean temperature, mean surface to bed temperature difference and mean thermocline depth, and the extent of the summer stratification are found to be in good agreement. Overall, the correlation between modelled and observed temperature is r2=0.95 for the depth mean component and r2=0.64 for the depth varying component. The rms deviation is about 1 degree. We assess the sources of these errors and the performance of the Mellor-Yamada level 2.5 turbulence closure as implemented in this model.

  7. Solar Cycle and Anthropogenic Forcing of Surface-Air Temperature at Armagh Observatory, Northern Ireland

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    2010-01-01

    A comparison of 10-yr moving average (yma) values of Armagh Observatory (Northern Ireland) surface-air temperatures with selected solar cycle indices (sunspot number (SSN) and the Aa geomagnetic index (Aa)), sea-surface temperatures in the Nino 3.4 region, and Mauna Loa carbon dioxide (CO2) (MLCO2) atmospheric concentration measurements reveals a strong correlation (r = 0.686) between the Armagh temperatures and Aa, especially, prior to about 1980 (r = 0.762 over the interval of 1873-1980). For the more recent interval 1963-2003, the strongest correlation (r = 0.877) is between Armagh temperatures and MLCO2 measurements. A bivariate fit using both Aa and Mauna Loa values results in a very strong fit (r = 0.948) for the interval 1963-2003, and a trivariate fit using Aa, SSN, and Mauna Loa values results in a slightly stronger fit (r = 0.952). Atmospheric CO2 concentration now appears to be the stronger driver of Armagh surface-air temperatures. An increase of 2 C above the long-term mean (9.2 C) at Armagh seems inevitable unless unabated increases in anthropogenic atmospheric gases can be curtailed. The present growth in 10-yma Armagh temperatures is about 0.05 C per yr since 1982. The present growth in MLCO2 is about 0.002 ppmv, based on an exponential fit using 10-yma values, although the growth appears to be steepening, thus, increasing the likelihood of deleterious effects attributed to global warming.

  8. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  9. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  10. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  11. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  12. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  13. The effect of aerosols and sea surface temperature on China's climate over the late twentieth century

    NASA Astrophysics Data System (ADS)

    Folini, Doris; Wild, Martin

    2015-04-01

    Focusing on China in the second half of the twentieth century, we examine the relative role of aerosols and prescribed, observation based sea surface temperatures (SSTs) for the evolution of surface solar radiation (SSR), surface air temperature (SAT), and precipitation in ensembles of transient (1870 - 2005) sensitivity experiments with the global climate model ECHAM5-HAM. Observations and simulations with transient SSTs and aerosol emissions agree reasonably well in eastern China in terms of SSR dimming (-6 +/- 2 W/m2/decade, 1960 - 2000), statistically non-significant JJA SAT trend (1950 - 2000), and drying in JJA from 1950 to 1990 (-2.5% to -3.5% per decade, essentially via reduction of convective precipitation). Other major observed features are not reproduce by the model, e.g. precipitation increase in the 1990s in the Yangtze valley, the strong warming in winter in northern parts of China and Mongolia, or SSR dimming in western China. For the model results, SO2 emissions are more relevant than emissions of black and organic carbon. Aerosol effects are less pronounced at higher model resolution. Transient SSTs are found to be crucial for decadal scale SAT variability over land, especially the strong warming in the 1990s, and, via SST forced reduction of cloud cover, for the ceasing of SSR dimming around the year 2000. Unforced cloud variability leads to relevant scatter (up to +/- 2 W/m2/decade) of modeled SSR trends at individual observation sites.

  14. Shrubs tracing sea surface temperature--Calluna vulgaris on the Faroe Islands.

    PubMed

    Beil, Ilka; Buras, Allan; Hallinger, Martin; Smiljanić, Marko; Wilmking, Martin

    2015-11-01

    The climate of Central and Northern Europe is highly influenced by the North Atlantic Ocean due to heat transfer from lower latitudes. Detailed knowledge about spatio-temporal variability of sea surface temperature (SST) in that region is thus of high interest for climate and environmental research. Because of the close relations between ocean and coastal climate and the climate sensitivity of plant growth, annual rings of woody plants in coastal regions might be used as a proxy for SST. We show here for the first time the proxy potential of the common and widespread evergreen dwarf shrub Calluna vulgaris (heather), using the Faroe Islands as our case study. Despite its small and irregular ring structure, the species seems suitable for dendroecological investigations. Ring width showed high and significant correlations with summer and winter air temperatures and SST. The C. vulgaris chronology from the Faroe Islands, placed directly within the North Atlantic Current, clearly reflects variations in summer SSTs over an area between Iceland and Scotland. Utilising shrubs like C. vulgaris as easy accessible and annually resolved proxies offers an interesting possibility for reconstruction of the coupled climate-ocean system at high latitudes. PMID:25620645

  15. The doubled CO2 climate - Impact of the sea surface temperature gradient

    NASA Technical Reports Server (NTRS)

    Rind, David

    1987-01-01

    The Goddard Institute for Space Studies (GISS) GCM of Hansen et al. (1983) was run, with 4 deg x 5 deg resolution, with doubled CO2 and two sets of sea surface temperature gradient distributions. One set was derived from the equilibrium doubled CO2 run of the 8 deg x 10 deg GISS GCM, with minimal high latitude amplification. The other set resembled closely the GFDL model results, with greater amplification. Both experiments had the same global mean surface air temperature change. The two experiments were often found to produce substantially different climate characteristics. With reduced high latitude amplification (set one), and thus, more equatorial warming, there was a greater increase in specific humidity and the greenhouse capacity of the atmosphere, resulting in a warmer atmosphere in general. Features such as the low-latitude precipitation, Hadley cell intensity, jet stream magnitude, and atmospheric energy transports all increased in comparison with the control run. In contrast, these features all decreased in the experiment with greater high latitude amplification (set two).

  16. Interannual variability of the air-sea heat exchange in the western Mediterranean in relation to the deep-water formation processes

    NASA Astrophysics Data System (ADS)

    Soto, J.; Criado Aldeanueva, F.; García Lafuente, J.; Sanchez Román, A.; Carracedo, L.

    2009-04-01

    A 60-year long time series of heat fluxes (long and short wave radiation, sensible and latent contributions) from NCEP reanalysis dataset and a 22-year long time series of Sea Surface Temperature (SST) from JPL AVHRR Oceans Pathfinder dataset have been combined to study the seasonal and interannual variability of air-sea heat exchanges over the Mediterranean Sea and correlate them with the characteristics of the Mediterranean outflow through the Strait of Gibraltar collected in the frame of the INGRES projects in the last years. Special attention has been devoted to the historically reported deep-water formation basin of the Western Mediterranean (Gulf of Lions) during the pre-conditioning (November and December) and winter seasons. Until around 1970, no clear trend is found in the net heat flux winter series since positive and negative anomalies are observed alternatively. From then onwards, negative anomalies are frequently observed until the 2003-2006 positive events. A net heat loss of about 150 W/m2 is observed in 2005, the highest value since 1956, especially due to evaporation losses towards the atmosphere. The anomalously cold air and sea surface temperature in the area help to increase this contribution that reflects in a higher fraction of Western Mediterranean Deep Water (WMDW) in the outflow through the Strait.

  17. Decadal power in land air temperatures: Is it statistically significant?

    NASA Astrophysics Data System (ADS)

    Thejll, Peter A.

    2001-12-01

    The geographical distribution and properties of the well-known 10-11 year signal in terrestrial temperature records is investigated. By analyzing the Global Historical Climate Network data for surface air temperatures we verify that the signal is strongest in North America and is similar in nature to that reported earlier by R. G. Currie. The decadal signal is statistically significant for individual stations, but it is not possible to show that the signal is statistically significant globally, using strict tests. In North America, during the twentieth century, the decadal variability in the solar activity cycle is associated with the decadal part of the North Atlantic Oscillation index series in such a way that both of these signals correspond to the same spatial pattern of cooling and warming. A method for testing statistical results with Monte Carlo trials on data fields with specified temporal structure and specific spatial correlation retained is presented.

  18. A new approach to quantifying soil temperature responses to changing air temperature and snow cover

    NASA Astrophysics Data System (ADS)

    Mackiewicz, Michael C.

    2012-08-01

    Seasonal snow cover provides an effective insulating barrier, separating shallow soil (0.25 m) from direct localized meteorological conditions. The effectiveness of this barrier is evident in a lag in the soil temperature response to changing air temperature. The causal relationship between air and soil temperatures is largely because of the presence or absence of snow cover, and is frequently characterized using linear regression analysis. However, the magnitude of the dampening effect of snow cover on the temperature response in shallow soils is obscured in linear regressions. In this study the author used multiple linear regression (MLR) with dummy predictor variables to quantify the degree of dampening between air and shallow soil temperatures in the presence and absence of snow cover at four Greenland sites. The dummy variables defining snow cover conditions were z = 0 for the absence of snow and z = 1 for the presence of snow cover. The MLR was reduced to two simple linear equations that were analyzed relative to z = 0 and z = 1 to enable validation of the selected equations. Compared with ordinary linear regression of the datasets, the MLR analysis yielded stronger coefficients of multiple determination and less variation in the estimated regression variables.

  19. Potential for seasonal prediction of Atlantic sea surface temperatures using the RAPID array at 26°N

    NASA Astrophysics Data System (ADS)

    Duchez, Aurélie; Courtois, Peggy; Hirschi, Joël; Josey, Simon A.; Smeed, David

    2016-04-01

    The Atlantic meridional overturning circulation (AMOC) plays a critical role in the climate system and is responsible for much of the meridional heat transported by the ocean. In this study, the potential of using AMOC observations from the 26°N RAPID array to predict North Atlantic sea surface temperatures (SSTs) is investigated for the first time. Using spatial correlations and a composite method, the AMOC anomaly is used as a precursor of North Atlantic sea-surface temperature anomalies (SSTAs). The results show that the AMOC leads a dipolar SSTA with maximum correlations between 2 and 5 months. The physical mechanism explaining the link between AMOC and SSTA is described as a seesaw mechanism where a strong AMOC anomaly increases the amount of heat advected north of 26° N as well as the SSTA, and decreases the heat content and the SSTA south of this section. In order to further understand the origins of this SSTA dipole, the respective contributions of the heat advected by the AMOC versus the Ekman transport and air-sea fluxes have been assessed. We found that at a 5-month lag, the Ekman component mainly contributes to the southern part of the dipole and cumulative air-sea fluxes only explain a small fraction of the SSTA variability. Given that the southern part of the SSTA dipole encompasses the main development region for Atlantic hurricanes, our results therefore suggest the potential for AMOC observations from 26°N to be used to complement existing seasonal hurricane forecasts in the Atlantic.

  20. Potential for seasonal prediction of Atlantic sea surface temperatures using the RAPID array at 26°N

    NASA Astrophysics Data System (ADS)

    Duchez, A.; Courtois, P.; Harris, E.; Josey, S. A.; Kanzow, T.; Marsh, R.; Smeed, D. A.; Hirschi, J. J.-M.

    2015-12-01

    The Atlantic meridional overturning circulation (AMOC) plays a critical role in the climate system and is responsible for much of the meridional heat transported by the ocean. In this paper, the potential of using AMOC observations from the 26° N RAPID array to predict North Atlantic sea surface temperatures is investigated for the first time. Using spatial correlations and a composite method, the AMOC anomaly is used as a precursor of North Atlantic sea-surface temperature anomalies (SSTAs). The results show that the AMOC leads a dipolar SSTA with maximum correlations between 2 and 5 months. The physical mechanism explaining the link between AMOC and SSTA is described as a seesaw mechanism where a strong AMOC anomaly increases the amount of heat advected north of 26° N as well as the SSTA, and decreases the heat content and the SSTA south of this section. In order to further understand the origins of this SSTA dipole, the respective contributions of the heat advected by the AMOC versus the Ekman transport and air-sea fluxes have been assessed. We found that at a 5-month lag, the Ekman component mainly contributes to the southern part of the dipole and cumulative air-sea fluxes only explain a small fraction of the SSTA variability. Given that the southern part of the SSTA dipole encompasses the main development region for Atlantic hurricanes, our results therefore suggest the potential for AMOC observations from 26° N to be used to complement existing seasonal hurricane forecasts in the Atlantic.

  1. Potential for seasonal prediction of Atlantic sea surface temperatures using the RAPID array at 26°N

    NASA Astrophysics Data System (ADS)

    Duchez, A.; Courtois, P.; Harris, E.; Josey, S. A.; Kanzow, T.; Marsh, R.; Smeed, D. A.; Hirschi, J. J.-M.

    2016-05-01

    The Atlantic meridional overturning circulation (AMOC) plays a critical role in the climate system and is responsible for much of the meridional heat transported by the ocean. In this paper, the potential of using AMOC observations from the 26°N RAPID array to predict North Atlantic sea surface temperatures is investigated for the first time. Using spatial correlations and a composite method, the AMOC anomaly is used as a precursor of North Atlantic sea-surface temperature anomalies (SSTAs). The results show that the AMOC leads a dipolar SSTA with maximum correlations between 2 and 5 months. The physical mechanism explaining the link between AMOC and SSTA is described as a seesaw mechanism where a strong AMOC anomaly increases the amount of heat advected north of 26°N as well as the SSTA, and decreases the heat content and the SSTA south of this section. In order to further understand the origins of this SSTA dipole, the respective contributions of the heat advected by the AMOC versus the Ekman transport and air-sea fluxes have been assessed. We found that at a 5-month lag, the Ekman component mainly contributes to the southern part of the dipole and cumulative air-sea fluxes only explain a small fraction of the SSTA variability. Given that the southern part of the SSTA dipole encompasses the main development region for Atlantic hurricanes, our results therefore suggest the potential for AMOC observations from 26°N to be used to complement existing seasonal hurricane forecasts in the Atlantic.

  2. Air-sea exchange of carbon dioxide in the Southern Ocean and Antarctic marginal ice zone

    NASA Astrophysics Data System (ADS)

    Butterworth, Brian J.; Miller, Scott D.

    2016-07-01

    Direct carbon dioxide flux measurements using eddy covariance from an icebreaker in the high-latitude Southern Ocean and Antarctic marginal ice zone are reported. Fluxes were combined with the measured water-air carbon dioxide partial pressure difference (ΔpCO2) to compute the air-sea gas transfer velocity (k, normalized to Schmidt number 660). The open water data showed a quadratic relationship between k (cm h-1) and the neutral 10 m wind speed (U10n, m s-1), kopen = 0.245 U10n2 + 1.3, in close agreement with decades old tracer-based results and much lower than cubic relationships inferred from previous open ocean eddy covariance studies. In the marginal ice zone, the effective gas transfer velocity decreased in proportion to sea ice cover, in contrast with predictions of enhanced gas exchange in the presence of sea ice. The combined open water and marginal ice zone results affect the calculated magnitude and spatial distribution of Southern Ocean carbon flux.

  3. Distribution and air-sea exchange of organochlorine pesticides in the North Pacific and the Arctic

    NASA Astrophysics Data System (ADS)

    Cai, Minghong; Ma, Yuxin; Xie, Zhiyong; Zhong, Guangcai; MöLler, Axel; Yang, Haizhen; Sturm, Renate; He, Jianfeng; Ebinghaus, Ralf; Meng, Xiang-Zhou

    2012-03-01

    Surface seawater and boundary layer air samples were collected on the icebreaker Xuelong (Snow Dragon) during the Fourth Chinese Arctic Research Expedition (CHINARE2010) cruise in the North Pacific and Arctic Oceans during 2010. Samples were analyzed for organochlorine pesticides (OCPs), including three isomers of hexachlorocyclohexane (HCH), hexachlorobenzene (HCB), and two isomers of heptachlor epoxide. The gaseous total HCH (ΣHCHs) concentrations were approximately four times lower (average 12.0 pg m-3) than those measured during CHINARE2008 (average 51.4 pg m-3), but were comparable to those measured during CHINARE2003 (average 13.4 pg m-3) in the same study area. These changes are consistent with the evident retreat of sea ice coverage from 2003 to 2008 and increase of sea ice coverage from 2008 to 2009 and 2010. Gaseous β-HCH concentrations in the atmosphere were typically below the method detection limit, consistent with the expectation that ocean currents provide the main transport pathway for β-HCH into the Arctic. The concentrations of all dissolved HCH isomers in seawater increase with increasing latitude, and levels of dissolved HCB also increase (from 5.7 to 7.1 pg L-1) at high latitudes (above 73°N). These results illustrate the role of cold condensation processes in the transport of OCPs. The observed air-sea gas exchange gradients in the Arctic Ocean mainly favored net deposition of OCPs, with the exception of those for β-HCH, which favored volatilization.

  4. Sea surface microlayers: A unified physicochemical and biological perspective of the air-ocean interface

    NASA Astrophysics Data System (ADS)

    Cunliffe, Michael; Engel, Anja; Frka, Sanja; Gašparović, Blaženka; Guitart, Carlos; Murrell, J. Colin; Salter, Matthew; Stolle, Christian; Upstill-Goddard, Robert; Wurl, Oliver

    2013-02-01

    The sea surface microlayer (SML) covers more than 70% of the Earth's surface and is the boundary layer interface between the ocean and the atmosphere. This important biogeochemical and ecological system is critical to a diverse range of Earth system processes, including the synthesis, transformation and cycling of organic material, and the air-sea exchange of gases, particles and aerosols. In this review we discuss the SML paradigm, taking into account physicochemical and biological characteristics that define SML structure and function. These include enrichments in biogenic molecules such as carbohydrates, lipids and proteinaceous material that contribute to organic carbon cycling, distinct microbial assemblages that participate in air-sea gas exchange, the generation of climate-active aerosols and the accumulation of anthropogenic pollutants with potentially serious implications for the health of the ocean. Characteristically large physical, chemical and biological gradients thus separate the SML from the underlying water and the available evidence implies that the SML retains its integrity over wide ranging environmental conditions. In support of this we present previously unpublished time series data on bacterioneuston composition and SML surfactant activity immediately following physical SML disruption; these imply timescales of the order of minutes for the reestablishment of the SML following disruption. A progressive approach to understanding the SML and hence its role in global biogeochemistry can only be achieved by considering as an integrated whole, all the key components of this complex environment.

  5. 2012/13 abnormal cold winter in Japan associated with Large-scale Atmospheric Circulation and Local Sea Surface Temperature over the Sea of Japan

    NASA Astrophysics Data System (ADS)

    Ando, Y.; Ogi, M.; Tachibana, Y.

    2013-12-01

    reference, the conventional AO index is shown by the gray line. (b) a 5-day running mean WP index, (c) area-averaged Surface Air Temperature anomalies in Japan, (d) Air Temperature anomalies, (e) heat flux anomalies, and (f) Sea Surface Temperature anomalies. The boxed area on the Sea of Japan indicates the area in which the (d)-(f) indexes were calculated.

  6. Updating sea spray aerosol emissions in the Community Multiscale Air Quality (CMAQ) model version 5.0.2

    NASA Astrophysics Data System (ADS)

    Gantt, B.; Kelly, J. T.; Bash, J. O.

    2015-11-01

    Sea spray aerosols (SSAs) impact the particle mass concentration and gas-particle partitioning in coastal environments, with implications for human and ecosystem health. Model evaluations of SSA emissions have mainly focused on the global scale, but regional-scale evaluations are also important due to the localized impact of SSAs on atmospheric chemistry near the coast. In this study, SSA emissions in the Community Multiscale Air Quality (CMAQ) model were updated to enhance the fine-mode size distribution, include sea surface temperature (SST) dependency, and reduce surf-enhanced emissions. Predictions from the updated CMAQ model and those of the previous release version, CMAQv5.0.2, were evaluated using several coastal and national observational data sets in the continental US. The updated emissions generally reduced model underestimates of sodium, chloride, and nitrate surface concentrations for coastal sites in the Bay Regional Atmospheric Chemistry Experiment (BRACE) near Tampa, Florida. Including SST dependency to the SSA emission parameterization led to increased sodium concentrations in the southeastern US and decreased concentrations along parts of the Pacific coast and northeastern US. The influence of sodium on the gas-particle partitioning of nitrate resulted in higher nitrate particle concentrations in many coastal urban areas due to increased condensation of nitric acid in the updated simulations, potentially affecting the predicted nitrogen deposition in sensitive ecosystems. Application of the updated SSA emissions to the California Research at the Nexus of Air Quality and Climate Change (CalNex) study period resulted in a modest improvement in the predicted surface concentration of sodium and nitrate at several central and southern California coastal sites. This update of SSA emissions enabled a more realistic simulation of the atmospheric chemistry in coastal environments where marine air mixes with urban pollution.

  7. A review of the sources of uncertainties when estimating global-scale turbulent air-sea fluxes

    NASA Astrophysics Data System (ADS)

    Brodeau, Laurent; Barnier, Bernard

    2015-04-01

    Bulk formulae are used to estimate turbulent air-sea fluxes needed to provide surface boundary conditions to most of present-day OGCMs, AGCMs and coupled Earth systems. This study aims at making an inventory of the major sources of uncertainties and errors made when estimating turbulent air-sea fluxes with the bulk method, namely wind stress, evaporation (latent heat flux) and sensible heat flux. We use 6-hourly near-surface atmospheric fields and daily SST of ERA-Interim to compute global estimates of these fluxes during the last three decades. Those fluxes are computed using different bulk routines and different types of physical and numerical simplifications widely used within the GCM community. Moreover, to assess the sensitivity of these flux estimates to possible errors in the input atmospheric fields and SST, user-controlled biases are applied to each of these fields prior to bulk computation. As a result, a quantification of the potential sources of uncertainties related to the accuracy of both the parametrization and input fields is proposed. Any parametrization-related approximation can also be expressed in terms of a bias on a given input field. We find that the largest source of flux uncertainties is the choice of the bulk algorithm used to estimate the bulk transfer coefficients. The resulting disagreement in terms of globally-averaged heat flux and evaporation is 8 W/m2 and 1 Sv. In mid latitudes, this heat flux disagreement is about 10 W/m2, which independently compares to a bias of 1 m/s in surface wind speed, 3° in SST, 0.5° in surface temperature, or a modification of 5% in the surface humidity. Our study also underlies the relative importance of the accuracy of the estimate of the air density and the specific humidity at saturation.

  8. Effect of water temperature on sea lamprey growth and lake trout survival

    SciTech Connect

    Swink, W.D. )

    1993-11-01

    Percent mortality of lake trout Salvelinus namaycush subjected to single sea lamprey Petromyzon marinus attacks did not differ significantly between lower-temperature (mortality = 54%; temperature [le] 10[degrees]C; N = 33) and higher-temperature (mortality = 69%; temperature = 12.8-14.4[degrees]C; N = 45) laboratory studies conducted from 1 June to 28 November 1989. However, sea lampreys fed longer and killed fewer fish in colder water (mean attachment 467.0 h; 18 fish killed) than in warmer water (mean attachment 161.7 h; 31 fish killed), probably because food consumption was lower in colder water. These results indicate that the number of fish killed by sea lampreys could be much greater in warmer water and that temperature must be considered when fish losses from sea lamprey attacks are estimated. Previous studies (Swink and Hanson 1989; Swink 1990) of the effects of single sea lamprey Petromyzon marinus attacks on lake trout Salvelinus namaycush showed significantly less lake trout mortality at temperatures of 10[degrees]C and lower than at higher temperatures. The reduced host mortality, however, could not be attributed solely to lower temperature because warmwater and coldwater attacks occurred during different seasons. In those studies, the author was unable to hold water temperature at 10[degrees]C or less in late summer and early fall, when most fish are killed by sea lampreys in the Great Lakes (Christie and Kolenosky 1980; Bergstedt and Schneider 1988). Modifications to the fish holding facilities at the Hammond Bay Biological Station in 1988 allowed maintenance of a limited amount of water at 10[degrees]C or less throughout the year. Hence, the objective of this study was to compare sea lamprey-induced mortality of lake trout at 10[degrees]C or less with that at 12.8-14.4[degrees]C during the normal feeding season (June through November). 15 refs., 1 fig., 1 tab.

  9. Air-sea Exchange of Polycyclic Aromatic Hydrocarbons (PAHs), Polychlorinated Biphenyls (PCBs), Organochlorine Pesticides (OCPs) and Polybrominated Diphenyl Ethers (PBDEs) in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Lammel, G. P.; Heil, A.; Kukucka, P.; Meixner, F. X.; Mulder, M. D.; Prybilova, P.; Prokes, R.; Rusina, T. S.; Song, G. Z.; Vrana, B.

    2015-12-01

    The marine atmospheric environment is a receptor for persistent organic pollutants (POPs) which are advected from sources on land, primary, such as biomass burning by-products (PAHs, dioxins), and secondary, such as volatilization from contaminated soils (PCBs, pesticides). Primary sources do not exist in the marine environment, except for PAHs (ship engines) but following previous atmospheric deposition, the sea surface may turn to a secondary source by reversal of diffusive air-sea mass exchange. No monitoring is in place. We studied the vertical fluxes of a wide range of primary and secondary emitted POPs based on measurements in air and surface seawater at a remote coastal site in the eastern Mediterranean (2012). To this end, silicon rubbers were used as passive water samplers, vertical concentration gradients were determined in air and fluxes were quantified based on Eddy covariance. Diffusive air-sea exchange fluxes of hexachlorocyclohexanes (HCHs) and semivolatile PAHs were found close to phase equilibrium, except one PAH, retene, a wood burning tracer, was found seasonally net-volatilisational. Some PCBs, p,p'-DDE, penta- and hexachlorobenzene (PeCB, HCB) were mostly net-depositional, while PBDEs were net-volatilizational. Fluxes determined at a a remote coastal site ranged -33 - +2.4 µg m-2 d-1 for PAHs and -4.0 - +0.3 µg m-2 d-1for halogenated compounds (< 0 means net-deposition, > 0 means net-volatilization). It is concluded that nowadays in open seas more pollutants are undergoing reversal of the direction of air-sea exchange. Recgional fire activity records in combination with box model simulations suggest that deposition of retene during summer is followed by a reversal of air-sea exchange. The seawater surface as secondary source of pollution should be assessed based on flux measurements across seasons and over longer time periods.

  10. Response of atmospheric pressure and air temperature to the solar events in October 2003

    NASA Astrophysics Data System (ADS)

    Avakyan, S. V.; Voronin, N. A.; Nikol'sky, G. A.

    2015-12-01

    Variations in the main weather parameters were studied for effects of solar flares and magnetic storms: the air temperature T and the atmospheric pressure P. We report the results of our comparison of these parameters measured at the mountain meteorological observatory near Kislovodsk (2100 m above sea level) to the monitoring data on strong solargeomagnetic perturbations for October 2003. We observed a decrease in the value of P for medium and large flares (of the type M > 4) in nine cases (82%) and an increase in T after magnetic storms with K p > 5 in 16 cases (84%). Hence, the manifestation of solar flares and magnetic storms in weather parameter variations ( T and P) at an altitude of 2100 m was proven, and the contribution of the radiooptical three-step trigger mechanism to solar-weather relations was qualitatively confirmed.

  11. Change point analysis of mean annual air temperature in Iran

    NASA Astrophysics Data System (ADS)

    Shirvani, A.

    2015-06-01

    The existence of change point in the mean of air temperature is an important indicator of climate change. In this study, Student's t parametric and Mann-Whitney nonparametric Change Point Models (CPMs) were applied to test whether a change point has occurred in the mean of annual Air Temperature Anomalies Time Series (ATATS) of 27 synoptic stations in different regions of Iran for the period 1956-2010. The Likelihood Ratio Test (LRT) was also applied to evaluate the detected change points. The ATATS of all stations except Bandar Anzali and Gorgan stations, which were serially correlated, were transformed to produce an uncorrelated pre-whitened time series as an input file for the CPMs and LRT. Both the Student's t and Mann-Whitney CPMs detected the change point in the ATATS of (a) Tehran Mehrabad, Abadan, Kermanshah, Khoramabad and Yazd in 1992, (b) Mashhad and Tabriz in 1993, (c) Bandar Anzali, Babolsar and Ramsar in 1994, (d) Kerman and Zahedan in 1996 at 5% significance level. The likelihood ratio test shows that the ATATS before and after detected change points in these 12 stations are normally distributed with different means. The Student's t and Mann-Whitney CPMs suggested different change points for individual stations in Bushehr, Bam, Shahroud, and Gorgan. However, the LRT confirmed the change points in these four stations as 1997, 1996, 1993, and 1996, respectively. No change points were detected in the remaining 11 stations.

  12. Sea level oscillations in coastal waters of the Buenos Aires province, Argentina

    NASA Astrophysics Data System (ADS)

    Dragani, W. C.; Mazio, C. A.; Nuñez, M. N.

    2002-03-01

    Sea level oscillations, with periods ranging from a few minutes to almost 2 h, have been observed at various tide stations located on the coast of Buenos Aires. Simultaneous records of sea level elevation measured in Mar de Ajó, Pinamar and Mar del Plata during 1982 have been spectrally analyzed. Significant spectral energy has been detected between 0.85 and 4.69 cycles per hour (cph) and the most energetic peaks have frequencies between 1.17 and 1.49 cph. Spectra, coherence, and phase difference have been analyzed for the most energetic event of the year. During that event, the most intensive spectral peak is at 1.17 cph for Mar de Ajó and Pinamar, and at 1.49 cph for Mar del Plata. Simultaneous total energy peaks at Mar de Ajó, Pinamar and Mar del Plata, and the coherence function estimated between Mar de Ajó and Pinamar suggests that sea level oscillations could be a regional phenomenon. The analyzed data suggest that sea level oscillations could be forced by atmospheric gravity waves associated with frontal passages.

  13. Sea surface temperature variability in the Norwegian Sea during the late Pliocene linked to subpolar gyre strength and radiative forcing