Science.gov

Sample records for flux climatologies derived

  1. Uncertainties in global ocean surface heat flux climatologies derived from ship observations

    SciTech Connect

    Gleckler, P.J.; Weare, B.C.

    1995-08-01

    A methodology to define uncertainties associated with ocean surface heat flux calculations has been developed and applied to a revised version of the Oberhuber global climatology, which utilizes a summary of the COADS surface observations. Systematic and random uncertainties in the net oceanic heat flux and each of its four components at individual grid points and for zonal averages have been estimated for each calendar month and the annual mean. The most important uncertainties of the 2{degree} x 2{degree} grid cell values of each of the heat fluxes are described. Annual mean net shortwave flux random uncertainties associated with errors in estimating cloud cover in the tropics yield total uncertainties which are greater than 25 W m{sup {minus}2}. In the northern latitudes, where the large number of observations substantially reduce the influence of these random errors, the systematic uncertainties in the utilized parameterization are largely responsible for total uncertainties in the shortwave fluxes which usually remain greater than 10 W m{sup {minus}2}. Systematic uncertainties dominate in the zonal means because spatial averaging has led to a further reduction of the random errors. The situation for the annual mean latent heat flux is somewhat different in that even for grid point values the contributions of the systematic uncertainties tend to be larger than those of the random uncertainties at most all latitudes. Latent heat flux uncertainties are greater than 20 W m{sup {minus}2} nearly everywhere south of 40{degree}N, and in excess of 30 W m{sup {minus}2} over broad areas of the subtropics, even those with large numbers of observations. Resulting zonal mean latent heat flux uncertainties are largest ({approximately}30 W m{sup {minus}2}) in the middle latitudes and subtropics and smallest ({approximately}10--25 W m{sup {minus}2}) near the equator and over the northernmost regions.

  2. 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.

  3. Derivation of Tropospheric Ozone Climatology and Trends from TOMS Data

    NASA Technical Reports Server (NTRS)

    Newchurch, Michael J.; McPeters, Rich; Logan, Jennifer; Kim, Jae-Hwan

    2002-01-01

    This research addresses the following three objectives: (1) Derive tropospheric ozone columns from the TOMS instruments by computing the difference between total-ozone columns over cloudy areas and over clear areas in the tropics; (2) Compute secular trends in Nimbus-7 derived tropospheric Ozone column amounts and associated potential trends in the decadal-scale tropical cloud climatology; (3) Explain the occurrence of anomalously high ozone retrievals over high ice clouds.

  4. Satellite derived aerosol optical depth climatology over Bangalore, India

    NASA Astrophysics Data System (ADS)

    Sreekanth, V.

    2013-06-01

    Climatological aerosol optical depths (AOD) over Bangalore, India have been examined to bring out the temporal heterogeneity in columnar aerosol characteristics. AOD values at 550 nm derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard NASA's Terra and Aqua satellites, for the period of 2002-2011 have been analyzed (independently) for the purpose. Frequency distributions of the AOD values are examined to infer the monthly mean values. Monthly and seasonal variations of AOD are investigated in the light of regional synoptic meteorology. Climatological monthly and seasonal mean Terra and Aqua AOD values exhibited similar temporal variation patterns. Monthly mean AOD values increased from January, peaks during May and thereafter (except for a secondary peak during July) fall off to reach a minimum during December. Monsoon season recorded the highest climatological seasonal mean AOD, while winter season recorded the lowest. AOD values show an overall increasing trend on a yearly basis, which was found mainly due to sustained increase in the seasonal averaged AOD during summer. The results obtained in the present study are compared with that of the earlier studies over the same location and also with AOD over various other Indian locations. Finally, the radiative and climatic impacts are discussed.

  5. Ocean-atmosphere interaction and the tropical climatology. Part I. The dangers of flux correction

    SciTech Connect

    Neelin, J.D.; Dijkstra, H.A.

    1995-05-01

    This sequence of papers examines the role of dynamical feedbacks between the ocean and the atmosphere in determining features of the tropical climatology. A stripped-down, intermediate, coupled ocean-atmosphere model is used to provide a prototype problem for the Pacific basin. Here the authors contrast the fully coupled case with the case where flux correction is used to construct the climatology. In the fully coupled case, the climatology is determined largely by feedback mechanisms within the ocean basin: winds driven by gradients of sea surface temperature (SST) within the basin interact with the ocean circulation to maintain SST gradients. For all realistic cases, these lead to a unique steady solution for the tropical climatology. In the flux-corrected case, the artificially constructed climatology becomes unstable at sufficiently large coupling, leading to multiple steady states as found in a number of coupled models. Using continuation methods, we show that there is a topological change in the bifurcation structure as flux correction is relaxed toward a fully coupled case; this change is characterized as an imperfection and must occur generically for all flux-corrected cases. The cold branch is steady solutions is governed by mechanisms similar to the fully coupled case. The warm branch, however, is spurious and disappears. The dynamics of this and consequences for coupled models are discussed. Multiple steady states can be ruled out as a mechanism for El Nino in favor of oscillatory mechanisms. The important role that coupled feedbacks are suggested to play in establishing tropical climatology is referred to as {open_quotes}the climatological version of the Bjerknes hypothesis.{close_quotes} 43 refs., 10 figs., 2 tabs.

  6. Climatology 2011: An MLS and Sonde Derived Ozone Climatology for Satellite Retrieval Algorithms

    NASA Technical Reports Server (NTRS)

    McPeters, Richard D.; Labow, Gordon J.

    2012-01-01

    The ozone climatology used as the a priori for the version 8 Solar Backscatter Ultraviolet (SBUV) retrieval algorithms has been updated. The Microwave Limb Sounder (MLS) instrument on Aura has excellent latitude coverage and measures ozone daily from the upper troposphere to the lower mesosphere. The new climatology consists of monthly average ozone profiles for ten degree latitude zones covering pressure altitudes from 0 to 65 km. The climatology was formed by combining data from Aura MLS (2004-2010) with data from balloon sondes (1988-2010). Ozone below 8 km (below 12 km at high latitudes) is based on balloons sondes, while ozone above 16 km (21 km at high latitudes) is based on MLS measurements. Sonde and MLS data are blended in the transition region. Ozone accuracy in the upper troposphere is greatly improved because of the near uniform coverage by Aura MLS, while the addition of a large number of balloon sonde measurements improves the accuracy in the lower troposphere, in the tropics and southern hemisphere in particular. The addition of MLS data also improves the accuracy of climatology in the upper stratosphere and lower mesosphere. The revised climatology has been used for the latest reprocessing of SBUV and TOMS satellite ozone data.

  7. Constraining the climatology of CO2 ocean surface flux for North Atlantic and the Arctic

    NASA Astrophysics Data System (ADS)

    Wróbel, Iwona; Piskozub, Jacek

    2015-04-01

    The ocean sink is an important part of the anthropogenic CO2 budget. Because the terrestrial biosphere is usually treated as a residual, constraining the net flux into the ocean sink is crucial for understanding the global carbon cycle. The air-sea interface flux is calculated from millions of measurements of CO2 partial pressures. However the regional and temporal means depend on parametrization of gas transfer velocity as well as on the wind/waves fields used for calculations. A recently developed tool, FluxEngine, created within the ESA funded (SOLAS related) OceanFlux Greenhouse Gases project, creates an opportunity to create an ensemble of regional CO2 flux climatologies for the North Atlantic and Arctic waters using multiple combinations of forcing fields and gas transfer velocity parameterizations. The aim of the study is to provide constraints on the regional monthly averages for the chosen area for the whole "climatology ensemble". This approach is similar to the one used by IPCC for the whole model ensemble used for modeling of the climate. Doing a regional study provides an additional test of the parameterizations because the local flux averages may differ even for parameterizations giving similar global averages. We present the methodology and CO2 flux climatology constrains for selected regions and seasons, the preliminary results of a study which aim is to cover the whole North Atlantic and ice-free areas of Arctic Ocean. The study is done within the new ESA funded OceanFlux Evolution project we are part of and at the same time is part of a PhD thesis funded by Centre of Polar Studies "POLAR-KNOW" (a project of the Polish Ministry of Science).

  8. A 40-year retrospective European radon flux inventory including climatological variability

    NASA Astrophysics Data System (ADS)

    López-Coto, I.; Mas, J. L.; Bolivar, J. P.

    2013-07-01

    In this work, a 40-year retrospective European radon flux inventory has been calculated. Average values of the radon exhalation rate, probability distributions and seasonal fluctuations have been obtained. To achieve this, a numerical model of radon transport through finite, heterogeneous and porous media has been implemented, enabling us to calculate the radon exhalation rate of European soils with a horizontal resolution of 0.5' (˜1 km). Geological, geochemical and climatological parameters derived from European and international databases (FOREGS, HWSD, ERA-40) have been coupled to the model. The theoretical model is based on the fundamental equation of radon transport in porous media, taking into account the dependency of the transport coefficient on temperature and humidity. It also includes a simple model that evaluates the effect of snow cover. In general, the results show wide variations depending on location and season of the year, with a spatial standard deviation close to the annual average value (30 Bq m-2 h-1) In turn, the seasonal deviation is about 25% of the annual average value. The inventory can be easily integrated into atmospheric transport models acting as baseline that could be used for policy decisions regarding the identification of areas with a high risk of exposure to radon. The gridded data are available for the scientific community upon request. The limitations and sources of errors and uncertainties of the model are also discussed in detail.

  9. Sensitivity of a climatologically-driven sea ice model to the ocean heat flux

    NASA Technical Reports Server (NTRS)

    Parkinson, C. L.; Good, M. R.

    1982-01-01

    Ocean heat flux sensitivity was studied on a numerical model of sea ice covering the Weddell Sea region of the southern ocean. The model is driven by mean monthly climatological atmospheric variables. For each model run, the ocean heat flux is uniform in both space and time. Ocean heat fluxes below 20 W m to the minus 2 power do not provide sufficient energy to allow the ice to melt to its summertime thicknesses and concentrations by the end of the 14 month simulation, whereas ocean heat fluxes of 30 W m to the minus 2 power and above result in too much ice melt, producing the almost total disappearance of ice in the Weddell Sea by the end of the 14 months. These results are dependent on the atmospheric forcing fields.

  10. Synoptic Climatological Approaches to Assessing Subcanopy Hydrologic and Nutrient Fluxes in a Temperate Deciduous Forest

    NASA Astrophysics Data System (ADS)

    Siegert, C. M.; Levia, D. F.; Leathers, D. J.

    2012-12-01

    The partitioning of precipitation incident to a forest canopy into throughfall and stemflow is controlled by biotic and abiotic factors. Biotic factors include canopy architecture, bark and leaf morphology, and leaf presence whereas abiotic factors include precipitation, antecedent moisture conditions, and wind speed. Previous studies relating the subcanopy hydrologic flux to storm events consider the aforementioned abiotic factors at the event level. This research applies atmospheric classification methods from the field of synoptic climatology to relate large scale weather patterns to local forest hydrologic conditions. A daily synoptic calendar is employed to categorize the observed subcanopy hydrologic flux during storm events and is evaluated as a tool for historical reconstruction and future prediction of forest hydrologic conditions as precipitation regimes are influenced by climate change. At the seasonal scale, the majority of precipitation occurs in 4 out of 13 synoptic types in winter, 4 out of 13 in spring, 2 out of 9 in summer, and 5 out of 11 in autumn, the remaining synoptic types are dominated by fair weather conditions (although small precipitation amounts are sometimes observed). During the study period, precipitation is correctly predicted by synoptic types 82% of the time in winter, 70% in spring, 88% in summer, and 73% in autumn. Analysis of variance (ANOVA) indicates that spring, summer, and fall precipitation-producing synoptic types predict statistically different subcanopy throughfall fluxes. The absence of foliage and more homogenous winter canopy may diminish the predictive ability of synoptic typing in regards to throughfall at that time of year. Biogeochemical canopy fluxes associated with storm events are also distinguishable using the synoptic calendar.

  11. A Global Climatology of Tropospheric and Stratospheric Ozone Derived from Aura OMI and MLS Measurements

    NASA Technical Reports Server (NTRS)

    Ziemke, J.R.; Chandra, S.; Labow, G.; Bhartia, P. K.; Froidevaux, L.; Witte, J. C.

    2011-01-01

    A global climatology of tropospheric and stratospheric column ozone is derived by combining six years of Aura Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) ozone measurements for the period October 2004 through December 2010. The OMI/MLS tropospheric ozone climatology exhibits large temporal and spatial variability which includes ozone accumulation zones in the tropical south Atlantic year-round and in the subtropical Mediterranean! Asia region in summer months. High levels of tropospheric ozone in the northern hemisphere also persist in mid-latitudes over the eastern North American and Asian continents extending eastward over the Pacific Ocean. For stratospheric ozone climatology from MLS, largest ozone abundance lies in the northern hemisphere in the latitude range 70degN-80degN in February-April and in the southern hemisphere around 40degS-50degS during months August-October. The largest stratospheric ozone abundances in the northern hemisphere lie over North America and eastern Asia extending eastward across the Pacific Ocean and in the southern hemisphere south of Australia extending eastward across the dateline. With the advent of many newly developing 3D chemistry and transport models it is advantageous to have such a dataset for evaluating the performance of the models in relation to dynamical and photochemical processes controlling the ozone distributions in the troposphere and stratosphere.

  12. A 10-Year Climatology of Amazonian Rainfall Derived from Passive Microwave Satellite Observations

    NASA Technical Reports Server (NTRS)

    Negri, Andrew J.; Anagnostou, Emmanouil N.; Adler, Robert F.

    1998-01-01

    In this study we present and describe a satellite-derived precipitation climatology over northern South America using a passive microwave technique, the Goddard Profiling Algorithm. A period of data slightly longer than 10 years is examined. The climatologies take the form of the mean estimated (adjusted) rainfall for a 10-year (+) period, with sub-divisions by month and meteorological season. For the six-year period 1992-1997, when two satellites were in operation, diurnal variability (to the extent it is discerned by four unequally spaced observations) is presented. We find an alternating pattern of morning and maxima stretching from the northeast (Atlantic coast) clear across the continent to the Pacific. The effects of topography, coastlines and geography (river valleys) on the rainfall patterns are clear. Interannual variability is examined by computing the deviations of yearly and warm season (DJF) rainfall from their respective long-term means. Interannual variability of the diurnal nature of the rainfall is presented, and the strong El Nino event of 1997-1998 is discussed.

  13. Climatological patterns over South America derived from COSMIC radio occultation data

    NASA Astrophysics Data System (ADS)

    Hierro, R.; Llamedo, P.; de la Torre, A.; Alexander, P.; Rolla, A.

    2012-02-01

    Meteorological phenomena are closely linked to the presence of water vapor. They mainly originate and develop in the troposphere, where almost all the atmospheric water is concentrated. The Global Positioning System radio occultation (GPS RO) technique provides vertical profiles of refractivity from which other properties such as temperature and water vapor can be derived. The GPS RO capability to reproduce global, synoptic, and regional climatological patterns over South America, which is a mostly oceanic continent, is tested. From FORMOSAT-3/COSMIC mission data (2006-2010), our previous knowledge regarding global and synoptic/regional patterns of temperature, equivalent potential temperature, specific humidity, and pressure is verified. Special cases such as baroclinic disturbances arriving at South American midlatitudes and storm events over a mountain region near the Andes are analyzed. The temporal evolution and the latitude-longitude distribution in several layers of the variables listed above are well described with this technique.

  14. Regional rainfall climatologies derived from Special Sensor Microwave Imager (SSM/I) data

    NASA Technical Reports Server (NTRS)

    Negri, Andrew J.; Adler, Robert F.; Nelkin, Eric J.; Huffman, George J.

    1994-01-01

    Climatologies of convective precipitation were derived from passive microwave observations from the Special Sensor Microwave Imager using a scattering-based algorithm of Adler et al. Data were aggregated over periods of 3-5 months using data from 4 to 5 years. Data were also stratified by satellite overpass times (primarily 06 00 and 18 00 local time). Four regions (Mexico, Amazonia, western Africa, and the western equatorial Pacific Ocean (TOGA COARE area) were chosen for their meteorological interest and relative paucity of conventional observations. The strong diurnal variation over Mexico and the southern United States was the most striking aspect of the climatologies. Pronounced morning maxima occured offshore, often in concativities in the coastline, the result of the increased convergence caused by the coastline shape. The major feature of the evening rain field was a linear-shaped maximum along the western slope of the Sierra Madre Occidental. Topography exerted a strong control on the rainfall in other areas, particularly near the Nicaragua/Honduras border and in Guatemala, where maxima in excess of 700 mm/month were located adjacent to local maxima in terrain. The correlation between the estimates and monthly gage data over the southern United States was low (0.45), due mainly to poor temporal sampling in any month and an inadequate sampling of the diurnal cycle. Over the Amazon Basin the differences in morning versus evening rainfall were complex, with an alternating series of morning/evening maxima aligned southwest to northeast from the Andes to the northeast Brazilian coast. A real extent of rainfall in Amazonia was slightly higher in the evening, but a maximum in morning precipitation was found on the Amazon River just east of Manaus. Precipitation over the water in the intertropical convergence zone (ITCZ) north of Brazil was more pronounced in the morning, and a pronounced land-/sea-breeze circulation was found along the northeast coast of Brazil

  15. Satellite-derived UV climatology over Europe: daily doses maps from January 1984 to October 2002

    NASA Astrophysics Data System (ADS)

    Verdebout, J.; Groebner, J.

    2003-04-01

    The paper presents a first version of a European satellite-derived ultraviolet (UV) radiation climatology over Europe, covering the period from January 1984 to October 2002. It consists in maps of the surface dose rates and daily doses, covering Europe (12E-32E, 34N-74N) with a spatial resolution of 0.05 deg. The method basically uses a standard radiative transfer code (UVspec) and exploits various sources of information to assign values to the influencing parameters. GOME, TOMS or TOVS data are used for the total column ozone. The attenuation of radiation by clouds is estimated using the MVIRI/METEOSAT visible channel data. In practice, for each METEOSAT pixel, the cloud optical thickness is derived from the enhancement of the signal with respect to the cloudless situation. Other influencing factors taken into account include tropospheric aerosols (using observations by ground meteorological stations), snow cover and surface elevation. The generated data set is made of daily maps of near noontime dose rates from which daily and monthly doses are extrapolated. The maps are available for several action spectra: UVA, UVB, erythemal, SCUPh, DNA and PLANT. The year-to-year variability of the UV radiation during the 19 years period, as deduced from this data set is illustrated. It varies according to the month and can reach ±50% over large areas. Variations are essentially due to changes in total column and cloudiness. These two factors are also documented separately. The validity of the results is discussed. Over such a period, the consistency of the input data and the impact on the modelled surface UV radiation is a critical issue for drawing conclusions on possible changes and trends. A partial validation of the results is demonstrated by comparison with ground UV measurements performed at Ispra, from 1992 to 2002.

  16. 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.

  17. Estimates of the climatological land surface energy- and water balance derived from thermodynamic constraints

    NASA Astrophysics Data System (ADS)

    Kleidon, Axel; Renner, Maik; Porada, Philipp

    2015-04-01

    The land surface energy and water balances are tightly coupled by the partitioning of absorbed solar radiation into terrestrial radiation and the turbulent fluxes of sensible and latent heat, as well as the partitioning of precipitation into evaporation and runoff. Evaporation forms the critical link between these two balances. Its rate is strongly affected by turbulent exchange as it provides the means to efficiently exchange moisture between the heated, moist surface and the cooled, dry atmosphere. Here, we use the constraint that this mass exchange operates at the thermodynamic limit of maximum power to derive analytical expressions for the partitioning of the surface energy and water balances on land. We use satellite-derived forcing of absorbed solar radiation, surface temperature and precipitation to derive simple spatial estimates for the annual mean fluxes of sensible and latent heat and evaluate these estimates with the ERA-Interim reanalysis data set and observations of the discharge of large river basins. Given the extremely simple approach, we find that our estimates explain the climatic mean variations in net radiation, evaporation, and river discharge reasonably well. We conclude that our analytical, minimum approach provides adequate first order estimates of the surface energy and water balance on land and that the thermodynamic limit of maximum power provides a useful closure assumption to constrain the energy partitioning at the land surface.

  18. Micropulse lidar-derived aerosol optical depth climatology at ARM sites worldwide

    NASA Astrophysics Data System (ADS)

    Kafle, D. N.; Coulter, R. L.

    2013-07-01

    This paper focuses on climatology of the vertical distribution of aerosol optical depth (AOD (z)) from micropulse lidar (MPL) observations for climatically different locations worldwide. For this, a large data set obtained by MPL systems operating at 532 nm during the 4 year period 2007-2010 was used to derive vertical profiles of AOD (z) by combining the corresponding AOD data as an input from an independent measurement using nearly colocated multifilter rotating shadowband radiometer (MFRSR) systems at five different U.S. Department of Energy Atmospheric Radiation Measurement (ARM) Program sites—three permanent sites (SGP in north-central Oklahoma, at 36.6°N, 97.5°W, 320 m; TWP-Darwin in the tropical western Pacific, at 12.4°S, 130.9°E, 30 m; and NSA at Barrow on the North Slope of Alaska, at 71.3°N, 156.6°W, 8 m) and two mobile facility sites (GRW at Graciosa Island in the Azores, at 39°N, 28°W, 15 m; and FKB in the Black Forest of Germany, at 48.5°N, 8.4°E, 511 m). Therefore, amount of data used in this study is constrained by the availability of the MFRSR data. The MPL raw data were averaged for 30 s in time and 30 m in altitude. The diurnally averaged AOD (z) profiles from 4 years were combined to obtain a multiyear vertical profile of AOD (z) climatology at various ARM sites, including diurnal, day-to-day, and seasonal variabilities. Most aerosols were found to be confined to 0-2 km (approximately the planetary boundary layer region) at all sites; however, all sites exhibited measurable aerosols well above the mixed layer, with different height maxima. The entire data set demonstrates large day-to-day variability at all sites. However, there is no significant diurnal variation in AOD (z) at all sites. Significant interannual variability was observed at the SGP site. Clear seasonal variations in AOD (z) profiles exist for all five sites, but seasonal behavior was distinct. Moreover, the different seasonal variability for the lower level (0 to ~2

  19. A Multiyear Dataset of SSM/I-Derived Global Ocean Surface Turbulent Fluxes

    NASA Technical Reports Server (NTRS)

    Chou, Shu-Hsien; Shie, Chung-Lin; Atlas, Robert M.; Ardizzone, Joe; Nelkin, Eric; Einaudi, Franco (Technical Monitor)

    2001-01-01

    climatological analyses of fluxes derived from ship observations.

  20. Oceanographic and climatologic controls on the compositions and fluxes of biogenic materials in the water column and sediments of the Cariaco Basin over the Late Holocene

    NASA Astrophysics Data System (ADS)

    Goni, M. A.; Aceves, H.; Benitez-Nelson, B.; Tappa, E.; Thunell, R.; Black, D. E.; Muller-Karger, F.; Astor, Y.; Varela, R.

    2009-04-01

    Materials collected by sediment traps over a 3-y period and sedimentary horizons from a gravity core covering the last 6000 y were used to investigate the effects of climate-related processes such as wind-driven upwelling and regional rainfall on the production, export and burial of particulate organic matter in the Cariaco Basin. A variety of chemical analyses, including organic carbon and nitrogen, biogenic opal, calcite, lithogenic contents, stable carbon isotopic ratios of organic matter and the yields of CuO reaction products derived from distinct biochemicals such as amino acids, fatty acids and lignins, were carried out for this purpose. Principal component analyses were used to investigate the trends in this multivariate data set. These analyses reveal marked temporal differences in the composition of the materials sinking through the water column, which were related to distinct oceanographic and climatic forcings. For example, autochthonous fluxes, characterized by elevated contents of organic carbon and opal as well as high yields of amino acid and fatty acid reaction products, displayed peaks during periods of intense wind-driven upwelling. In contrast, allochthonous materials, characterized by elevated lithogenic contents and elevated yields of lignin-derived products, were more important during periods of high rainfall, low wind and enhanced stratification. In addition to the strong seasonal contrasts, there was significant temporal variability at both shorter (monthly) and longer (inter-annual) time scales. Hence, other factors, such as zooplankton grazing and El Niño effects on local climatology, may also be important. Examination of the gravity core record yielded several significant trends. For example, there was a marked increase in sediment accumulation rates from 5000 to ca. 700 y before present with concomitant increases in the concentrations of organic carbon, opal and most biomarkers. These results suggest that the Cariaco Basin experienced

  1. Climatology of low latitude ionosphere under effect of varying solar flux during solar cycle 23 and 24

    NASA Astrophysics Data System (ADS)

    Dashora, Nirvikar; Suresh, Sunanda

    2016-07-01

    The characteristics of quiet time equatorial and low latitude total electron content (TEC) over the Indian sector using GIM data (1998-2014) is obtained. For the first time the analysis is carried filtering out the solar flare and storm effects and time series of quiet time VTEC data from three locations namely dip equator and two low latitude conjugate locations in Indian sector are obtained. It is well known that a complex interplay among drivers of equatorial electrodynamics like Solar flux, dynamo electric field and meridional winds determine the daytime ionization and distribution in equatorial ionization anomaly zone. In this study, we have critically examined the role of varying solar flux and response of low latitude ionosphere with new and standardized definitions. The results are examined and interpreted in the context of large number of previous studies. The newly found features from this study are as follows. Marked difference in nature of equinoctial asymmetry is noted between solar cycle 23 and 24. Long absence of winter anomaly both during low and high solar activity (HSA) in LL (low latitude) regions is found. Climatology of the diurnal cycle is provided in four categories using new criteria for demarcation of solar activity levels. Highest correlation (~77%) between GIM ionospheric electron content (IEC) and PI (solar EUV proxy index) is noted over equator in contrast to previous studies. The minimum positive contribution of PI in variation of IEC requires minimum of 2 years of data and if more than 7-8 years of data is used, it saturates. RMS (root mean square) width of PI can be used to define the HSA. Strong QBO (quasi biennial oscillations) in IEC is noted in tune with the one in PI over both the LL location but QBO remains surprisingly subdued over equator. The semi-annual oscillations in GIM-IEC are found to be stronger at all locations during high solar activity and weaker between 2005 and 2011, whereas, the annual oscillations are found to

  2. Climatology of Dry Layers in the Tropical Troposphere Derived from CONTRAST Observations and GFS Analyses

    NASA Astrophysics Data System (ADS)

    Randel, W. J.; Rivoire, L.; Pan, L.; Honomichl, S.

    2015-12-01

    A recent airborne field experiment in the remote tropical western Pacific, CONTRAST (CONvective Transport of Active Species in the Tropics), obtained over 80 vertical profiles of water vapor, ozone and numerous trace species from the surface to above 14 km during January-February 2014. These observations showed the frequent occurrence of extreme dry layers (relative humidity < 20%) co-located with enhanced ozone, occurring primarily over altitudes ~4-10 km. We compare these water vapor measurements with analyses from the NCEP Global Forecast System (GFS), and find good overall agreement. We then use the GFS analyses to quantify the climatological variability of extreme dry layers in the tropical troposphere, finding frequent occurrence in the subtropics of both hemispheres during winter-spring. The space-time structure of the dry layers, in addition to the strong anti-correlation between water vapor and ozone, suggests frequent transport to the tropics from the extratropical upper troposphere - lower stratosphere (UTLS).

  3. Carbon monoxide climatology derived from the trajectory mapping of global MOZAIC-IAGOS data

    NASA Astrophysics Data System (ADS)

    Osman, M.; Tarasick, D. W.; Liu, J.; Moeini, O.; Thouret, V.; Fioletov, V. E.; Parrington, M.; Nédélec, P.

    2015-11-01

    A three-dimensional gridded climatology of carbon monoxide (CO) has been developed by trajectory mapping of global MOZAIC-IAGOS in situ measurements from commercial aircraft data. CO measurements made during aircraft ascent and descent, comprising nearly 41 200 profiles at 148 airports worldwide from December 2001 to December 2012 are used. Forward and backward trajectories are calculated from meteorological reanalysis data in order to map the CO measurements to other locations, and so to fill in the spatial domain. This domain-filling technique employs 15 800 000 calculated trajectories to map otherwise sparse MOZAIC-IAGOS data into a quasi-global field. The resulting trajectory-mapped CO dataset is archived monthly from 2001-2012 on a grid of 5° longitude × 5° latitude × 1 km altitude, from the surface to 14 km altitude. The mapping product has been carefully evaluated, by comparing maps constructed using only forward trajectories and using only backward trajectories. The two methods show similar global CO distribution patterns. The magnitude of their differences is most commonly 10 % or less, and found to be less than 30 % for almost all cases. The trajectory-mapped CO dataset has also been validated by comparison profiles for individual airports with those produced by the mapping method when data from that site are excluded. While there are larger differences below 2 km, the two methods agree very well between 2 and 10 km with the magnitude of biases within 20 %. Maps are also compared with Version 6 data from the Measurements Of Pollution In The Troposphere (MOPITT) satellite instrument. While agreement is good in the lowermost troposphere, the MOPITT CO profile shows negative biases of ~ 20 % between 500 and 300 hPa. These upper troposphere biases are not related to the mapping procedure, as almost identical differences are found with the original in situ MOZAIC-IAGOS data. The total CO trajectory-mapped MOZAIC-IAGOS climatology column agrees with the

  4. Pacific Region Integrated Climatology Information Products (PRICIP) Derived-data Products

    NASA Astrophysics Data System (ADS)

    Marra, J. J.

    2008-12-01

    The National Oceanic and Atmospheric Administration (NOAA) Integrated Data and Environmental Applications (IDEA) Center has initiated the Pacific Region Integrated Climatology Information Products (PRICIP) project to improve our understanding of patterns and trends of storm frequency and intensity - 'storminess'- within the Pacific region and develop a suite of integrated data and information products. Strong winds, heavy rains, and high seas theme-specific data integration and product development teams have been formed to carry out this work. These teams are comprised of recognized agency and university- based experts in the area of climate-related processes that govern storminess. They include representatives from NOAA's National Climatic Data Center (NCDC), Center for Operational Products and Services (CO-OPS), and National Weather Service (NWS), as well as the University of Hawai'i, University of Alaska, University of Guam, and Oregon State University. Each team is developing regional climatological overviews, identifying corresponding extremes indices, establishing data treatment and analysis protocols, and conducting analyses to establish baseline statistics, long term trends, patterns of variability, and event return recurrence intervals via Generalized Extreme Value (GEV) analyses. Preliminary results of these analyses can be viewed via a beta-version of a Google map- based query utility (http://www.pricip.org/ddp.php ). Data sources for these analyses include NOAA's Integrated Surface Hourly (ISH) mean sea level pressure and wind speed data; the Global Historical Climate Network (GHCN) precipitation dataset; the National Water Level Observing Network (NWLON) sea level station records; the National Data Buoy Center (NDBC) wave buoy records; the U.S. Army Corps of Engineers" Coastal Data Information (CDIP) buoy data, and other data. The northern and central north Pacific, which includes Alaska, the Pacific Northwest, and Hawai'i, have been targeted as

  5. Radiation Climatology of the Greenland Ice Sheet Derived from Greenland Climate Network Data

    NASA Technical Reports Server (NTRS)

    Steffen, Konrad; Box, Jason

    2003-01-01

    The magnitude of shortwave and longwave dative fluxes are critical to surface energy balance variations over the Greenland ice sheet, affecting many aspects of its climate, including melt rates, the nature of low-level temperature inversions, the katabatic wind regime and buoyant stability of the atmosphere. Nevertheless, reliable measurements of the radiative fluxes over the ice sheet are few in number, and have been of limited duration and areal distribution (e.g. Ambach, 1960; 1963, Konzelmann et al., 1994, Harding et al., 1995, Van den Broeke, 1996). Hourly GC-Net radiation flux measurements spanning 1995-2001 period have been used to produce a monthly dataset of surface radiation balance components. The measurements are distributed widely across Greenland and incorporate multiple sensors

  6. Surface radiation climatology derived from Meteosat First and Second Generation satellites

    NASA Astrophysics Data System (ADS)

    Posselt, Rebekka; Müller, Richard; Trentmann, Jörg; Stöckli, Reto

    2010-05-01

    A 25 year long continuous and consistently validated surface incoming shortwave (SIS) radiation climate data record (CDR) from METEOSAT satellites is MeteoSwiss' contribution to CM SAF (Satellite Application Facility for Climate Monitoring). CM SAF is is a joint activity of several national Meteorological Services within EUMETSAT's satellite data processing (SAF - Satellite Application Facilities). CM SAF generates, archives and distributes widely recognized high-quality satellite-derived products and services relevant for climate monitoring in operational mode with a special emphasis on the retrieval of climate variables such as cloud parameters, radiation budget and water vapor. The SIS CDR by MeteoSwiss and DWD is generated using an extended Heliosat algorithm which exploits the attenuation of radiation by clouds from the METEOSAT visible channel, and using the MAGIC (Mesoscale Atmospheric Global Irradiance Code) radiative transfer model that accounts for water vapor, ozone and aerosol absorption on clear sky radiation fluxes. The dataset is compared to reference surface radiation datasets from ISCCP, GEWEX and ERA interim. Ground based measurements of the BSRN (Baseline surface radiation network) and ASRB (Alpine surface radiation budget) network are used as validation sources to estimate the uncertainty of the SIS CDR and of the reference datasets. In order to satisfy the dataset accuracy required for climate variability and change studies, discontinuities due to changes in satellite instrumentation must be avoided. Therefore, a selfcalibration technique within the Heliosat algorithm is applied. It uses the 95% percentile of the measured radiance distribution obtained in a selected (nearly) always cloudy region in the southern Atlantic. The overlap period between two satellites/instruments (Meteosat7 and Meteosat8 in 2005) is used to examine and validate the performance of the selfcalibration. First validation results show a good agreement for both satellite

  7. Carbon monoxide climatology derived from the trajectory mapping of global MOZAIC-IAGOS data

    NASA Astrophysics Data System (ADS)

    Osman, Mohammed K.; Tarasick, David W.; Liu, Jane; Moeini, Omid; Thouret, Valerie; Fioletov, Vitali E.; Parrington, Mark; Nédélec, Philippe

    2016-08-01

    A three-dimensional gridded climatology of carbon monoxide (CO) has been developed by trajectory mapping of global MOZAIC-IAGOS in situ measurements from commercial aircraft data. CO measurements made during aircraft ascent and descent, comprising nearly 41 200 profiles at 148 airports worldwide from December 2001 to December 2012, are used. Forward and backward trajectories are calculated from meteorological reanalysis data in order to map the CO measurements to other locations and so to fill in the spatial domain. This domain-filling technique employs 15 800 000 calculated trajectories to map otherwise sparse MOZAIC-IAGOS data into a quasi-global field. The resulting trajectory-mapped CO data set is archived monthly from 2001 to 2012 on a grid of 5° longitude × 5° latitude × 1 km altitude, from the surface to 14 km altitude.The mapping product has been carefully evaluated, firstly by comparing maps constructed using only forward trajectories and using only backward trajectories. The two methods show similar global CO distribution patterns. The magnitude of their differences is most commonly 10 % or less and found to be less than 30 % for almost all cases. Secondly, the method has been validated by comparing profiles for individual airports with those produced by the mapping method when data from that site are excluded. While there are larger differences below 2 km, the two methods agree very well between 2 and 10 km with the magnitude of biases within 20 %. Finally, the mapping product is compared with global MOZAIC-IAGOS cruise-level data, which were not included in the trajectory-mapped data set, and with independent data from the NOAA aircraft flask sampling program. The trajectory-mapped MOZAIC-IAGOS CO values show generally good agreement with both independent data sets.Maps are also compared with version 6 data from the Measurements Of Pollution In The Troposphere (MOPITT) satellite instrument. Both data sets clearly show major regional CO sources such

  8. A regional rainfall climatology over Mexico and the southwest United States derived from passive microwave and geosynchronous infrared data

    NASA Technical Reports Server (NTRS)

    Negri, Andrew J.; Adler, Robert F.; Maddox, Robert A.; Howard, Kenneth W.; Keehn, Peter R.

    1993-01-01

    A three-year climatology of satellite-estimated rainfall for the warm season for the southwest United States and Mexico has been derived from data from the Special Sensor Microwave Imager (SSM/I). The microwave data have been stratified by month (June, July, August), year (1988, 1989, 1990), and time of day (morning and evening orbits). A rain algorithm was employed that relates 86-GHz brightness temperatures to rain rate using a coupled cloud-radiative transfer model. Results identify an early evening maximum in rainfall along the western slope of the Sierra Madre Occidental during all three months. A prominent morning rainfall maximum was found off the western Mexican coast near Mazatlan in July and August. Substantial differences between morning and evening estimates were noted. To the extent that three years constitute a climatology, results of interannual variability are presented. Results are compared and contrasted to high-resolution (8 km, hourly) infrared cloud climatologies, which consist of the frequency of occurrence of cloud colder than -38 C and -58 C. This comparison has broad implications for the estimation of rainfall by simple (cloud threshold) techniques. By sampling the infrared data to approximate the time and space resolution of the microwave, we produce ratios (or adjustment factors) by which we can adjust the infrared rain estimation schemes. This produces a combined microwave/infrared rain algorithm for monthly rainfall. Using a limited set of raingage data as ground truth, an improvement (lower bias and root-mean-square error) was demonstrated by this combined technique when compared to either method alone. The diurnal variability of convection during July 1990 was examined using hourly rain estimates from the Geostationary Operational Environmental Satellite (GOES) precipitation index and the convective stratiform technique, revealing a maximum in estimated rainfall from 1800 to 2100 local time. It is in this time period when the SSM

  9. Seven-Year SSM/I-Derived Global Ocean Surface Turbulent Fluxes

    NASA Technical Reports Server (NTRS)

    Chou, Shu-Hsien; Shie, Chung-Lin; Atlas, Robert M.; Ardizzone, Joe

    2000-01-01

    A 7.5-year (July 1987-December 1994) dataset of daily surface specific humidity and turbulent fluxes (momentum, latent heat, and sensible heat) over global oceans has been retrieved from the Special Sensor Microwave/Imager (SSM/I) data and other data. It has a spatial resolution of 2.0 deg.x 2.5 deg. latitude-longitude. The retrieved surface specific humidity is generally accurate over global oceans as validated against the collocated radiosonde observations. The retrieved daily wind stresses and latent heat fluxes show useful accuracy as verified by those measured by the RV Moana Wave and IMET buoy in the western equatorial Pacific. The derived turbulent fluxes and input variables are also found to agree generally with the global distributions of annual-and seasonal-means of those based on 4-year (1990-93) comprehensive ocean-atmosphere data set (COADS) with adjustment in wind speeds and other climatological studies. The COADS has collected the most complete surface marine observations, mainly from merchant ships. However, ship measurements generally have poor accuracy, and variable spatial coverages. Significant differences between the retrieved and COADS-based are found in some areas of the tropical and southern extratropical oceans, reflecting the paucity of ship observations outside the northern extratropical oceans. Averaged over the global oceans, the retrieved wind stress is smaller but the latent heat flux is larger than those based on COADS. The former is suggested to be mainly due to overestimation of the adjusted ship-estimated wind speeds (depending on sea states), while the latter is suggested to be mainly due to overestimation of ship-measured dew point temperatures. The study suggests that the SSM/I-derived turbulent fluxes can be used for climate studies and coupled model validations.

  10. A Multilayer Dataset of SSM/I-Derived Global Ocean Surface Turbulent Fluxes

    NASA Technical Reports Server (NTRS)

    Chou, Shu-Hsien; Shie, Chung-Lin; Atlas, Robert M.; Ardizzone, Joe; Nelkin, Eric; Einaud, Franco (Technical Monitor)

    2001-01-01

    A dataset including daily- and monthly-mean turbulent fluxes (momentum, latent heat, and sensible heat) and some relevant parameters over global oceans, derived from the Special Sensor Microwave/Imager (SSM/I) data, for the period July 1987-December 1994 and the 1988-94 annual and monthly-mean climatologies of the same variables is created. It has a spatial resolution of 2.0deg x 2.5deg latitude-longitude. The retrieved surface air humidity is found to be generally accurate as compared to the collocated radiosonde observations over global oceans. The retrieved wind stress and latent heat flux show useful accuracy as verified against research quality measurements of ship and buoy in the western equatorial Pacific. The 1988-94 seasonal-mean wind stress and latent heat flux show reasonable patterns related to seasonal variations of the atmospheric general circulation. The patterns of 1990-93 annual-mean turbulent fluxes and input variables are generally in good agreement with one of the best global analyzed flux datasets that based on COADS (comprehensive ocean-atmosphere data set) with corrections on wind speeds and covered the same period. The retrieved wind speed is generally within +/-1 m/s of the COADS-based, but is stronger by approx. 1-2 m/s in the northern extratropical oceans. The discrepancy is suggested to be mainly due to higher COADS-modified wind speeds resulting from underestimation of anemometer heights. Compared to the COADS-based, the retrieved latent heat flux and sea-air humidity difference are generally larger with significant differences in the trade wind zones and the ocean south of 40degS (up to approx. 40-60 W/sq m and approx. 1-1.5 g/kg). The discrepancy is believed to be mainly caused by higher COADS-based surface air humidity arising from the overestimation of dew point temperatures and from the extrapolation of observed high humidity southward into data-void regions south of 40degS. The retrieved sensible heat flux is generally within +/-5

  11. Climatological and radiative properties of midlatitude cirrus clouds derived by automatic evaluation of lidar measurements

    NASA Astrophysics Data System (ADS)

    Kienast-Sjögren, Erika; Rolf, Christian; Seifert, Patric; Krieger, Ulrich K.; Luo, Bei P.; Krämer, Martina; Peter, Thomas

    2016-06-01

    Cirrus, i.e., high, thin clouds that are fully glaciated, play an important role in the Earth's radiation budget as they interact with both long- and shortwave radiation and affect the water vapor budget of the upper troposphere and stratosphere. Here, we present a climatology of midlatitude cirrus clouds measured with the same type of ground-based lidar at three midlatitude research stations: at the Swiss high alpine Jungfraujoch station (3580 m a.s.l.), in Zürich (Switzerland, 510 m a.s.l.), and in Jülich (Germany, 100 m a.s.l.). The analysis is based on 13 000 h of measurements from 2010 to 2014. To automatically evaluate this extensive data set, we have developed the Fast LIdar Cirrus Algorithm (FLICA), which combines a pixel-based cloud-detection scheme with the classic lidar evaluation techniques. We find mean cirrus optical depths of 0.12 on Jungfraujoch and of 0.14 and 0.17 in Zürich and Jülich, respectively. Above Jungfraujoch, subvisible cirrus clouds (τ < 0.03) have been observed during 6 % of the observation time, whereas above Zürich and Jülich fewer clouds of that type were observed. Cirrus have been observed up to altitudes of 14.4 km a.s.l. above Jungfraujoch, whereas they have only been observed to about 1 km lower at the other stations. These features highlight the advantage of the high-altitude station Jungfraujoch, which is often in the free troposphere above the polluted boundary layer, thus enabling lidar measurements of thinner and higher clouds. In addition, the measurements suggest a change in cloud morphology at Jungfraujoch above ˜ 13 km, possibly because high particle number densities form in the observed cirrus clouds, when many ice crystals nucleate in the high supersaturations following rapid uplifts in lee waves above mountainous terrain. The retrieved optical properties are used as input for a radiative transfer model to estimate the net cloud radiative forcing, CRFNET, for the analyzed cirrus clouds. All cirrus detected

  12. New features of global climatology revealed by satellite-derived oceanic rainfall maps

    NASA Technical Reports Server (NTRS)

    Rao, M. S. V.; Theon, J. S.

    1977-01-01

    Quantitative rainfall maps over the oceanic areas of the globe were derived from the Nimbus 5 Electrically Scanning Microwave Radiometer (ESMR) data. Analysis of satellite derived oceanic rainfall maps reveal certain distinctive characteristics of global patterns for the years 1973-74. The main ones are (1) the forking of the Intertropical Convergence Zone in the Pacific, (2) a previously unrecognized rain area in the South Atlantic, (3) the bimodal behavior of rainbelts in the Indian Ocean and (4) the large interannual variability in oceanic rainfall. These features are discussed.

  13. Upper Stratospheric Temperature Climatology Derived from SAGE II Observations: Preliminary Results

    NASA Technical Reports Server (NTRS)

    Wang, P.-H.; Cunnold, D. M.; Wang, H. J.; Chu, W. P.; Thomason, L. W.

    2002-01-01

    This study shows that the temperature information in the upper stratosphere can be derived from the SAGE II 385-mn observations. The preliminary results indicate that the zonal mean temperature increases with altitude below 50 km and decreases above 50 km. At 50 km, a regional maximum of 263 K is located in the tropics, and a minimum of 261 K occurs in the subtropics in both hemispheres. The derived long-term temperature changes from 1985 to 1997 reveal a statistically significant negative trend of -2 to -2.5 K/decade in the tropical upper stratosphere and about -2 K/decade in the subtropics near the stratopause. At latitudes poleward of 50, the results show a statistically significant positive trend of about 1 K/decade in the upper stratosphere. The preliminary results also show large annual temperature oscillations in the extratropics with a maximum amplitude of approx. 8 K located at about 44 km near 50 in both hemispheres during local summer. In addition, the semiannual oscillation is found to be a maximum in the tropics with a peak amplitude of approx. 3.3 K located at about 42 km during the equinox.

  14. A 3-Year Climatology of Cloud and Radiative Properties Derived from GOES-8 Data Over the Southern Great Plains

    NASA Technical Reports Server (NTRS)

    Khaiyer, M. M.; Rapp, A. D.; Doelling, D. R.; Nordeen, M. L.; Minnis, P.; Smith, W. L., Jr.; Nguyen, L.

    2001-01-01

    While the various instruments maintained at the Atmospheric Radiation Measurement (ARM) Program Southern Great Plains (SGP) Central Facility (CF) provide detailed cloud and radiation measurements for a small area, satellite cloud property retrievals provide a means of examining the large-scale properties of the surrounding region over an extended period of time. Seasonal and inter-annual climatological trends can be analyzed with such a dataset. For this purpose, monthly datasets of cloud and radiative properties from December 1996 through November 1999 over the SGP region have been derived using the layered bispectral threshold method (LBTM). The properties derived include cloud optical depths (ODs), temperatures and albedos, and are produced on two grids of lower (0.5 deg) and higher resolution (0.3 deg) centered on the ARM SGP CF. The extensive time period and high-resolution of the inner grid of this dataset allows for comparison with the suite of instruments located at the ARM CF. In particular, Whole-Sky Imager (WSI) and the Active Remote Sensing of Clouds (ARSCL) cloud products can be compared to the cloud amounts and heights of the LBTM 0.3 deg grid box encompassing the CF site. The WSI provides cloud fraction and the ARSCL computes cloud fraction, base, and top heights using the algorithms by Clothiaux et al. (2001) with a combination of Belfort Laser Ceilometer (BLC), Millimeter Wave Cloud Radar (MMCR), and Micropulse Lidar (MPL) data. This paper summarizes the results of the LBTM analysis for 3 years of GOES-8 data over the SGP and examines the differences between surface and satellite-based estimates of cloud fraction.

  15. Fluxes Derivation From a Given Space Object Population

    NASA Astrophysics Data System (ADS)

    X, K.; Pang, Baojun; Peng, Keke

    A particulate environment model is indispensable for describing a space debris environment. The purpose of a space debris environment engineering model is the realistic description of the man-made particulate environment surrounding the Earth and risk assessment via flux predictions for defined target orbits. This paper provides a method for deriving fluxes using data sources whose orbital elements are known (e.g., two-line elements (TLE) data). First, we present the definitions of the output parameters used in the Meteoroid and Space Debris Terrestrial Reference Model of the European Space Agency and summarize the concepts used in the modeling. Second, we convert the original data into a new data format that can be used in deriving fluxes; the new data are equivalent to the original ones. Third, we deriving fluxes regarding the TLEs as the only data source. Finally, we analyze the results for different years and consider the prospects of applying the technique to sources whose orbital elements are unknown.

  16. Linking Carbon Fluxes with Remotely-Sensed Vegetation Indices for Leaf Area and Aboveground Biomass Through Footprint Climatology

    NASA Astrophysics Data System (ADS)

    Wayson, C.; Clark, K.; Hollinger, D. Y.; Skowronski, N.; Schmid, H. E.

    2010-12-01

    A major challenge of bottom-up scaling is that in-situ flux observations are spatially limited. Thus, to achieve valid regional exchange rates, models are used to interpolate and extrapolate to the vegetational/spatial domain covered by these observations. To parameterize these models from flux data, efforts must be made to select data that best represents the region being modeled as well as linking the fluxes to remotely-sensed data products that can be produced from site to regional scales. Because most long-term flux stations are not in spatially extensive, homogeneous locations, this requirement is often a challenge. However, this requirement can be met by selecting observation periods whose flux footprints are statistically representative of the type of ecosystem identified in the model. The flux footprint function indicates the time-varying surface “field-of-view” (or spatial sampling window) of an eddy-flux sensor, oriented mostly in upwind direction. For each observation period, the modeled flux footprint window is overlain with a high-resolution vegetation index map to determine a footprint-weighted vegetation index for which the observation is representative. Using flux-footprint analysis to link fluxes to models using just an enhanced vegetation index (EVI) map shows a positive trend between EVI and eddy covariance measured fluxes, but the link is not strong. Leaf area is linked with carbon (C) uptake, but forests tend to maximize leaf area, as determined through remote sensing, early on with forests having similar leaf areas across a wide range of ages. Adding another remotely-sensed dataset, aboveground biomass map (AGB), helps capture the processes of lower productivity rates (as biomass increases per unit of leaf area there is a decline, due to the forest ageing) and the C losses due to respiration, both heterotrophic and autotrophic (linked to live and detrital biomass pools). Adding biomass from LIDAR and a combined EVI-biomass layer to examine

  17. 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.

  18. Aerosol properties derived from spectral actinic flux measurements

    NASA Astrophysics Data System (ADS)

    Stark, H.; Schmidt, K. S.; Pilewskie, P.; Cozic, J.; Wollny, A. G.; Brock, C. A.; Baynard, T.; Lack, D.; Parrish, D. D.; Fehsenfeld, F. C.

    2008-12-01

    Measurement of aerosol properties is very important for understanding climate change. Aerosol optical properties influence solar radiation throughout the troposphere. According to the Working Group I report of the intergovernmental panel for climate change [IPCC, 2007], aerosols have a direct radiative forcing of - 0.5±0.4 W/m2 with a medium to low level of scientific understanding. This relatively large uncertainty indicates the need for more frequent and precise measurements of aerosol properties. We will show how actinic flux measurements can be used to derive important optical aerosol parameters such as aerosol optical thickness and depth, surface albedo, angstrom exponent, radiative forcing by clouds and aerosols, aerosol extinction, and others. The instrument used for this study is a combination of two spectroradiometers measuring actinic flux in the ultraviolet and visible radiation range from 280 to 690 nm with a resolution of 1 nm. Actinic flux is measured as the radiation incident on a spherical surface with sensitivity independent of direction. In contrast, irradiance is measured as the radiation incident on a plane surface, which depends on the cosine of the incident angle. Our goal is to assess the capabilities of using spectral actinic flux measurements to derive various aerosol properties. Here we will compare 1) actinic flux measurements to irradiance measurements from the spectral solar flux radiometer (SSFR), 2) derived aerosol size distributions with measurements from a white light optical particle counter (WLOPC) and ultra high sensitivity aerosol size spectrometer (UHSAS), and 3) derived aerosol optical extinction with measurements from a cavity ringdown aerosol extinction spectrometer (CRD-AES). These comparisons will utilize data from three recent field campaigns over New England and the Atlantic Ocean (ICARTT 2004), Texas and the Gulf of Mexico during (TexAQS/GoMACCS 2006), and Alaska and the Arctic Ocean (ARCPAC 2008) when the instruments

  19. Satellite-derived Springtime Uv Climatology Over Europe: Months of March, April and May From 1984 To 2001

    NASA Astrophysics Data System (ADS)

    Verdebout, J.

    The poster presents progress made in the building of a satellite-derived ultraviolet (UV) radiation climatology over Europe, covering the last 10 to 20 years. The method- ology to model the surface UV with satellite and ancillary geophysical data has been initially developed and evaluated during the European project MAUVE. The resulting products are maps of the surface dose rates and daily doses, covering Europe (12E- 32E, 34N-74N) with a spatial resolution of 0.05 deg. The method basically consists in using a standard radiative transfer code (UVspec) and in exploiting various sources of information to assign values to the influencing parameters. GOME, TOMS or TOVS data are used for the total column ozone. The attenuation of radiation by clouds is estimated using the MVIRI/METEOSAT visible channel data. In practice, for each METEOSAT pixel, a cloud liquid water path is derived from the enhancement of the signal with respect to the cloudless situation. Other influencing factors taken into ac- count include the tropospheric aerosols (using the observations by the ground mete- orological stations), the snow cover and the surface elevation. The paper presents the results for the months of March, April and May from 1984 to 2001. The generated data set is made of daily maps of near noontime dose rates from which daily and monthly doses are extrapolated. The maps are available for several action spectra: UVA, UVB, erythemal, SCUPh, DNA and PLANT. The variability of the UV radiation during the 18 years period, as deduced from this data set is illustrated. The year-to-year varia- tions are essentially due to changes in total column and cloudiness. These two factors are also documented separately. The validity of the results is discussed. Over such a period, the consistency of the input data and the impact on the modelled surface UV radiation is a critical issue for drawing conclusions on possible changes and trends. A partial validation of the results is demonstrated by

  20. The Climatological Annual Cycle of Satellite-derived Phytoplankton Pigments in the Alboran Sea: A Physical Interpretation

    NASA Technical Reports Server (NTRS)

    Garcia-Gorriz, E.; Carr, M. E.

    1998-01-01

    The circulation and upwelling processes (coastal and gyre-induced) that control the phytoplankton distribution in the Alboran sea are examined by analyzing monthly climatological patterns of Coastal Zone Color Scanner (CZCS) pigment concentrations, sea surface temperatures, winds, and seasonal geostrophic fields.

  1. The SPARC Intercomparison of Middle Atmosphere Climatologies

    NASA Technical Reports Server (NTRS)

    Randel, William; Fleming, Eric; Geller, Marvin; Gelman, Mel; Hamilton, Kevin; Karoly, David; Ortland, Dave; Pawson, Steve; Swinbank, Richard; Udelhofen, Petra

    2003-01-01

    Our current confidence in 'observed' climatological winds and temperatures in the middle atmosphere (over altitudes approx. 10-80 km) is assessed by detailed intercomparisons of contemporary and historic data sets. These data sets include global meteorological analyses and assimilations, climatologies derived from research satellite measurements, and historical reference atmosphere circulation statistics. We also include comparisons with historical rocketsonde wind and temperature data, and with more recent lidar temperature measurements. The comparisons focus on a few basic circulation statistics, such as temperature, zonal wind, and eddy flux statistics. Special attention is focused on tropical winds and temperatures, where large differences exist among separate analyses. Assimilated data sets provide the most realistic tropical variability, but substantial differences exist among current schemes.

  2. Clear sky atmosphere at cm-wavelengths from climatology data

    NASA Astrophysics Data System (ADS)

    Lew, Bartosz; Uscka-Kowalkowska, Joanna

    2016-01-01

    We utilize ground-based, balloon-borne and satellite climatology data to reconstruct site and season-dependent vertical profiles of precipitable water vapour (PWV). We use these profiles to solve radiative transfer through the atmosphere, and derive atmospheric brightness temperature (Tatm) and optical depth (τ) at centimetre wavelengths. We validate the reconstruction by comparing the model column PWV with photometric measurements of PWV, performed in clear sky conditions pointed towards the Sun. Based on the measurements, we devise a selection criteria to filter the climatology data to match the PWV levels to the expectations of the clear sky conditions. We apply the reconstruction to the location of a Polish 32-metre radio telescope, and characterize Tatm and τ year round, at selected frequencies. We also derive the zenith distance dependence for these parameters, and discuss the shortcomings of using planar, single-layer and optically thin atmospheric models in continuum radio-source flux-density measurement calibrations. We obtain PWV-Tatm and PWV-τ scaling relations in clear sky conditions, and constrain limits to which the actual Tatm and τ can deviate from those derived solely from the climatological data. Finally, we suggest a statistical method to detect clear sky that involves ground-level measurements of relative humidity. Accuracy is tested using local climatological data. The method may be useful to constrain cloud cover in cases when no other (and more robust) climatological data are available.

  3. Urban Climatology

    NASA Technical Reports Server (NTRS)

    Brazel, Anthony J.; Quattrochi, Dale A.; Arnold, James E. (Technical Monitor)

    2002-01-01

    This section on Urban Climates provides a basic understanding of what comprises the urban climate and what factors control the overall development of the urban climate. We also discuss in this section, methods for evaluating urban climate characteristics and forcing functions as well as how the urban heat island effect comes into play as a dynamic influence on urban climatology. Additionally, we examine and discuss the major radiation and energy balance of city (i.e., shortwave and longwave radiation, albedo, net all-wave radiation, total energy balance, and sensible latent, and storage heat) and the interactions of these energy balances with the lower atmosphere. The use of remote sensing to measure urban surface temperatures as a driving force in the development of the urban heat island effect is presented. We also discuss how the overall moisture, precipitation, humidity, and air movement in cities (i,e,, wind speeds and wind direction) and wind environment of the city affects urban climatology.

  4. An application of remotely derived climatological fields for risk assessment of vector-borne diseases : a spatial study of filariasis prevalence in the Nile Delta, Egypt.

    SciTech Connect

    Crombie, M. K.; Gillies, R. R.; Arvidson, R. E.; Brookmeyer, P.; Weil, G. J.; Sultan, M.; Harb, M.; Environmental Research; Washington Univ.; Utah State Univ.; Egyptian Ministry of Health

    1999-12-01

    This paper applies a relatively straightforward remote sensing method that is commonly used to derive climatological variables. Measurements of surface reflectance and surface radiant temperature derived from Landsat Thematic Mapper data were used to create maps of fractional vegetation and surface soil moisture availability for the southern Nile delta in Egypt. These climatological variables were subsequently used to investigate the spatial distribution of the vector borne disease Bancroftian filariasis in the Nile delta where it is focally endemic and a growing problem. Averaged surface soil moisture values, computed for a 5-km border area around affected villages, were compared to filariasis prevalence rates. Prevalence rates were found to be negligible below a critical soil moisture value of 0.2, presumably because of a lack of appropriate breeding sites for the Culex Pipiens mosquito species. With appropriate modifications to account for local conditions and vector species, this approach should be useful as a means to map, predict, and control insect vector-borne diseases that critically depend on wet areas for propagation. This type of analysis may help governments and health agencies that are involved in filariasis control to better focus limited resources to identifiable high-risk areas.

  5. Detect signals of interdecadal climate variations from an enhanced suite of reconstructed precipitation products since 1850 using the historical station data from Global Historical Climatology Network and the dynamical patterns derived from Global Precipitation Climatology Project

    NASA Astrophysics Data System (ADS)

    Shen, S. S.

    2015-12-01

    This presentation describes the detection of interdecadal climate signals in a newly reconstructed precipitation data from 1850-present. Examples are on precipitation signatures of East Asian Monsoon (EAM), Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillations (AMO). The new reconstruction dataset is an enhanced edition of a suite of global precipitation products reconstructed by Spectral Optimal Gridding of Precipitation Version 1.0 (SOGP 1.0). The maximum temporal coverage is 1850-present and the spatial coverage is quasi-global (75S, 75N). This enhanced version has three different temporal resolutions (5-day, monthly, and annual) and two different spatial resolutions (2.5 deg and 5.0 deg). It also has a friendly Graphical User Interface (GUI). SOGP uses a multivariate regression method using an empirical orthogonal function (EOF) expansion. The Global Precipitation Climatology Project (GPCP) precipitation data from 1981-20010 are used to calculate the EOFs. The Global Historical Climatology Network (GHCN) gridded data are used to calculate the regression coefficients for reconstructions. The sampling errors of the reconstruction are analyzed according to the number of EOF modes used in the reconstruction. Our reconstructed 1900-2011 time series of the global average annual precipitation shows a 0.024 (mm/day)/100a trend, which is very close to the trend derived from the mean of 25 models of the CMIP5 (Coupled Model Intercomparison Project Phase 5). Our reconstruction has been validated by GPCP data after 1979. Our reconstruction successfully displays the 1877 El Nino (see the attached figure), which is considered a validation before 1900. Our precipitation products are publically available online, including digital data, precipitation animations, computer codes, readme files, and the user manual. This work is a joint effort of San Diego State University (Sam Shen, Gregori Clarke, Christian Junjinger, Nancy Tafolla, Barbara Sperberg, and

  6. A 7.5-Year Dataset of SSM/I-Derived Surface Turbulent Fluxes Over Global Oceans

    NASA Technical Reports Server (NTRS)

    Chou, Shu-Hsien; Shie, Chung-Lin; Atlas, Robert M.; Ardizzone, Joe; Nelkin, Eric; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The surface turbulent fluxes of momentum, latent heat, and sensible heat over global oceans are essential to weather, climate and ocean problems. Wind stress is the major forcing for driving the oceanic circulation, while Evaporation is a key component of hydrological cycle and surface heat budget. We have produced a 7.5-year (July 1987-December 1994) dataset of daily, individual monthly-mean and climatological (1988-94) monthly-mean surface turbulent fluxes over the global oceans from measurements of the Special Sensor Microwave/Imager (SSM/I) on board the US Defense Meteorological Satellite Program F8, F10, and F11 satellites. It has a spatial resolution of 2.0x2.5 latitude-longitude. Daily turbulent fluxes are derived from daily data of SSM/I surface winds and specific humidity, National Centers for Environmental Prediction (NCEP) sea surface temperatures, and European Centre for Medium-Range Weather Forecasts (ECMWF) air-sea temperature differences, using a stability-dependent bulk scheme. The retrieved instantaneous surface air humidity (with a 25-km resolution) IS found to be generally accurate as compared to the collocated radiosonde observations over global oceans. The surface wind speed and specific humidity (latent heat flux) derived from the F10 SSM/I are found to be -encrally smaller (larger) than those retrieved from the F11 SSM/I. The F11 SSM/I appears to have slightly better retrieval accuracy for surface wind speed and humidity as compared to the F10 SSM/I. This difference may be due to the orbital drift of the F10 satellite. The daily wind stresses and latent heat fluxes retrieved from F10 and F11 SSM/Is show useful accuracy as verified against the research quality in si -neasurerrients (IMET buoy, RV Moana Wave, and RV Wecoma) in the western Pacific warm pool during the TOGA COARE Intensive observing period (November 1992-February 1993). The 1988-94 seasonal-mean turbulent fluxes and input variables derived from FS and F11 SSM/Is show reasonable

  7. Multiscale climatological albedo look-up maps derived from moderate resolution imaging spectroradiometer BRDF/albedo products

    NASA Astrophysics Data System (ADS)

    Gao, Feng; He, Tao; Wang, Zhuosen; Ghimire, Bardan; Shuai, Yanmin; Masek, Jeffrey; Schaaf, Crystal; Williams, Christopher

    2014-01-01

    Surface albedo determines radiative forcing and is a key parameter for driving Earth's climate. Better characterization of surface albedo for individual land cover types can reduce the uncertainty in estimating changes to Earth's radiation balance due to land cover change. This paper presents albedo look-up maps (LUMs) using a multiscale hierarchical approach based on moderate resolution imaging spectroradiometer (MODIS) bidirectional reflectance distribution function (BRDF)/albedo products and Landsat imagery. Ten years (2001 to 2011) of MODIS BRDF/albedo products were used to generate global albedo climatology. Albedo LUMs of land cover classes defined by the International Geosphere-Biosphere Programme (IGBP) at multiple spatial resolutions were generated. The albedo LUMs included monthly statistics of white-sky (diffuse) and black-sky (direct) albedo for each IGBP class for visible, near-infrared, and shortwave broadband under both snow-free and snow-covered conditions. The albedo LUMs were assessed by using the annual MODIS IGBP land cover map and the projected land use scenarios from the Intergovernmental Panel on Climate Change land-use harmonization project. The comparisons between the reconstructed albedo and the MODIS albedo data product show good agreement. The LUMs provide high temporal and spatial resolution global albedo statistics without gaps for investigating albedo variations under different land cover scenarios and could be used for land surface modeling.

  8. NASA GLDAS Evapotranspiration Data and Climatology

    NASA Technical Reports Server (NTRS)

    Rui, Hualan; Beaudoing, Hiroko Kato; Teng, William L.; Vollmer, Bruce; Rodell, Matthew

    2012-01-01

    Evapotranspiration (ET) is the water lost to the atmosphere by evaporation and transpiration. ET is a shared component in the energy and water budget, therefore, a critical variable for global energy and water cycle and climate change studies. However, direct ET measurements and data acquisition are difficult and expensive, especially at the global level. Therefore, modeling is one common alternative for estimating ET. With the goal to generate optimal fields of land surface states and fluxes, the Global Land Data Assimilation System (GLDAS) has been generating quality-controlled, spatially and temporally consistent, terrestrial hydrologic data, including ET and other variables that affect evaporation and transpiration, such as temperature, precipitation, humidity, wind, soil moisture, heat flux, and solar radiation. This poster presents the long-term ET climatology (mean and monthly), derived from the 61-year GLDAS-2 monthly 1.0 deg x 1.0 deg. NOAH model Experiment-1 data, and describes the basic characteristics of spatial and seasonal variations of the climatology. The time series of GLDAS-2 precipitation and radiation, and ET are also discussed to show the improvement of GLDAS-2 forcing data and model output over those from GLDAS-1.

  9. Siberia snow depth climatology derived from SSM/I data using a combined dynamic and static algorithm

    USGS Publications Warehouse

    Grippa, M.; Mognard, N.; Le, Toan T.; Josberger, E.G.

    2004-01-01

    One of the major challenges in determining snow depth (SD) from passive microwave measurements is to take into account the spatiotemporal variations of the snow grain size. Static algorithms based on a constant snow grain size cannot provide accurate estimates of snow pack thickness, particularly over large regions where the snow pack is subjected to big spatial temperature variations. A recent dynamic algorithm that accounts for the dependence of the microwave scattering on the snow grain size has been developed to estimate snow depth from the Special Sensor Microwave/Imager (SSM/I) over the Northern Great Plains (NGP) in the US. In this paper, we develop a combined dynamic and static algorithm to estimate snow depth from 13 years of SSM/I observations over Central Siberia. This region is characterised by extremely cold surface air temperatures and by the presence of permafrost that significantly affects the ground temperature. The dynamic algorithm is implemented to take into account these effects and it yields accurate snow depths early in the winter, when thin snowpacks combine with cold air temperatures to generate rapid crystal growth. However, it is not applicable later in the winter when the grain size growth slows. Combining the dynamic algorithm to a static algorithm, with a temporally constant but spatially varying coefficient, we obtain reasonable snow depth estimates throughout the entire snow season. Validation is carried out by comparing the satellite snow depth monthly averages to monthly climatological data. We show that the location of the snow depth maxima and minima is improved when applying the combined algorithm, since its dynamic portion explicitly incorporate the thermal gradient through the snowpack. The results obtained are presented and evaluated for five different vegetation zones of Central Siberia. Comparison with in situ measurements is also shown and discussed. ?? 2004 Elsevier Inc. All rights reserved.

  10. Validation of Improved Broadband Shortwave and Longwave Fluxes Derived From GOES

    NASA Technical Reports Server (NTRS)

    Khaiyer, Mandana M.; Nordeen, Michele L.; Palikonda, Rabindra; Yi, Yuhong; Minnis, Patrick; Doelling, David R.

    2009-01-01

    Broadband (BB) shortwave (SW) and longwave (LW) fluxes at TOA (Top of Atmosphere) are crucial parameters in the study of climate and can be monitored over large portions of the Earth's surface using satellites. The VISST (Visible Infrared Solar Split-Window Technique) satellite retrieval algorithm facilitates derivation of these parameters from the Geostationery Operational Environmental Satellites (GOES). However, only narrowband (NB) fluxes are available from GOES, so this derivation requires use of narrowband-to-broadband (NB-BB) conversion coefficients. The accuracy of these coefficients affects the validity of the derived broadband (BB) fluxes. Most recently, NB-BB fits were re-derived using the NB fluxes from VISST/GOES data with BB fluxes observed by the CERES (Clouds and the Earth's Radiant Energy Budget) instrument aboard Terra, a sun-synchronous polar-orbiting satellite that crosses the equator at 10:30 LT. Subsequent comparison with ARM's (Atmospheric Radiation Measurement) BBHRP (Broadband Heating Rate Profile) BB fluxes revealed that while the derived broadband fluxes agreed well with CERES near the Terra overpass times, the accuracy of both LW and SW fluxes decreased farther away from the overpass times. Terra's orbit hampers the ability of the NB-BB fits to capture diurnal variability. To account for this in the LW, seasonal NB-BB fits are derived separately for day and night. Information from hourly SW BB fluxes from the Meteosat-8 Geostationary Earth Radiation Budget (GERB) is employed to include samples over the complete solar zenith angle (SZA) range sampled by Terra. The BB fluxes derived from these improved NB-BB fits are compared to BB fluxes computed with a radiative transfer model.

  11. A Climatology of Tropospheric CO over the Central and Southeastern United States and the Southwestern Pacific Ocean Derived from Space, Air, and Ground-based Infrared Interferometer Spectra

    NASA Technical Reports Server (NTRS)

    McMillian, W. Wallace; Strow, L. Larrabee; Revercomb, H.; Knuteson, R.; Thompson, A.

    2003-01-01

    This final report summarizes all research activities and publications undertaken as part of NASA Atmospheric Chemistry and Modeling Analysis Program (ACMAP) Grant NAG-1-2022, 'A Climatology of Tropospheric CO over the Central and Southeastern United States and the Southwestern Pacific Ocean Derived from Space, Air, and Ground-based Infrared Interferometer Spectra'. Major project accomplishments include: (1) analysis of more than 300,000 AERI spectra from the ARM SGP site yielding a 5-year (1998-2002) timeseries of CO retrievals from the Lamont, OK AERI; (2) development of a prototype CO profile retrieval algorithm for AERI spectra; (3) validation and publication of the first CO retrievals from the Scanning High-resolution Interferometer Sounder (SHIS); and (4) development of a prototype AERI tropospheric O3 retrieval algorithm. Compilation and publication of the 5-year Lamont, OK timeseries is underway including a new collaboration with scientists at the Lawrence Berkeley National Laboratory. Public access to this data will be provided upon article submission. A comprehensive CO analysis of the archive of HIS spectra of remains as the only originally proposed activity with little progress. The greatest challenge faced in this project was motivating the University of Wisconsin Co-Investigators to deliver their archived HIS and AERIOO data along with the requisite temperature and water vapor profiles in a timely manner. Part of the supplied HIS dataset from ASHOE may be analyzed as part of a Master s Thesis under a separate project. Our success with the SAFARI 2000 SHIS CO analysis demonstrates the utility of such aircraft remote sensing data given the proper support from the instrument investigators. In addition to the PI and Co-I s, personnel involved in this CO climatology project include one Post Doctoral Fellow, one Research Scientist, two graduate students, and two undergraduate students. A total of fifteen presentations regarding research related to this

  12. Derivation of Improved Surface and TOA Broadband Fluxes Using CERES-derived Narrowband-to-Broadband Coefficients

    NASA Technical Reports Server (NTRS)

    Khaiyer, Mandana M.; Doelling, David R.; Chan, Pui K.; Nordeen, MIchele L.; Palikonda, Rabindra; Yi, Yuhong; Minnis, Patrick

    2006-01-01

    Satellites can provide global coverage of a number of climatically important radiative parameters, including broadband (BB) shortwave (SW) and longwave (LW) fluxes at the top of the atmosphere (TOA) and surface. These parameters can be estimated from narrowband (NB) Geostationary Operational Environmental Satellite (GOES) data, but their accuracy is highly dependent on the validity of the narrowband-to-broadband (NB-BB) conversion formulas that are used to convert the NB fluxes to broadband values. The formula coefficients have historically been derived by regressing matched polarorbiting satellite BB fluxes or radiances with their NB counterparts from GOES (e.g., Minnis et al., 1984). More recently, the coefficients have been based on matched Earth Radiation Budget Experiment (ERBE) and GOES-6 data (Minnis and Smith, 1998). The Clouds and the Earth's Radiant Energy Budget (CERES see Wielicki et al. 1998)) project has recently developed much improved Angular Distribution Models (ADM; Loeb et al., 2003) and has higher resolution data compared to ERBE. A limited set of coefficients was also derived from matched GOES-8 and CERES data taken on Topical Rainfall Measuring Mission (TRMM) satellite (Chakrapani et al., 2003; Doelling et al., 2003). The NB-BB coefficients derived from CERES and the GOES suite should yield more accurate BB fluxes than from ERBE, but are limited spatially and seasonally. With CERES data taken from Terra and Aqua, it is now possible to derive more reliable NB-BB coefficients for any given area. Better TOA fluxes should translate to improved surface radiation fluxes derived using various algorithms. As part of an ongoing effort to provide accurate BB flux estimates for the Atmospheric Radiation Measurement (ARM) Program, this paper documents the derivation of new NB-BB coefficients for the ARM Southern Great Plains (SGP) domain and for the Darwin region of the Tropical Western Pacific (DTWP) domain.

  13. Sources of discrepancies between satellite-derived and land surface model estimates of latent heat fluxes

    NASA Astrophysics Data System (ADS)

    Lipton, Alan E.; Liang, Pan; Jiménez, Carlos; Moncet, Jean-Luc; Aires, Filipe; Prigent, Catherine; Lynch, Richard; Galantowicz, John F.; d'Entremont, Robert P.; Uymin, Gennady

    2015-03-01

    Monthly-average estimates of latent heat flux have been derived from a combination of satellite-derived microwave emissivities, day-night differences in land surface temperature (from microwave AMSR-E), downward solar and infrared fluxes from ISCCP cloud analysis, and MODIS visible and near-infrared surface reflectances. The estimates, produced with a neural network, were compared with data from the Noah land surface model, as produced for GLDAS-2, and with two alternative estimates derived from different datasets and methods. Areas with extensive, persistent, substantial discrepancies between the satellite and land surface model fluxes have been analyzed with the aid of data from flux towers. The sources of discrepancies were found to include problems with the model surface roughness length and turbulent exchange coefficients for midlatitude cropland areas in summer, inaccuracies in the precipitation data that were used as forcing for the land surface model, and model underestimation of transpiration in some forests during dry periods. At the tower sites analyzed, agreement with tower data was generally closer for our satellite-derived fluxes than for the land surface model fluxes, in terms of monthly averages.

  14. Real-time soil flux measurements and calculations with CRDS + Soil Flux Processor: comparison among flux algorithms and derivation of whole system error

    NASA Astrophysics Data System (ADS)

    Alstad, K. P.; Venterea, R. T.; Tan, S. M.; Saad, N.

    2015-12-01

    Understanding chamber-based soil flux model fitting and measurement error is key to scaling soils GHG emissions and resolving the primary uncertainties in climate and management feedbacks at regional scales. One key challenge is the selection of the correct empirical model applied to soil flux rate analysis in chamber-based experiments. Another challenge is the characterization of error in the chamber measurement. Traditionally, most chamber-based N2O and CH4 measurements and model derivations have used discrete sampling for GC analysis, and have been conducted using extended chamber deployment periods (DP) which are expected to result in substantial alteration of the pre-deployment flux. The development of high-precision, high-frequency CRDS analyzers has advanced the science of soil flux analysis by facilitating much shorter DP and, in theory, less chamber-induced suppression of the soil-atmosphere diffusion gradient. As well, a new software tool developed by Picarro (the "Soil Flux Processor" or "SFP") links the power of Cavity Ring-Down Spectroscopy (CRDS) technology with an easy-to-use interface that features flexible sample-ID and run-schemes, and provides real-time monitoring of chamber accumulations and environmental conditions. The SFP also includes a sophisticated flux analysis interface which offers a user-defined model selection, including three predominant fit algorithms as default, and an open-code interface for user-composed algorithms. The SFP is designed to couple with the Picarro G2508 system, an analyzer which simplifies soils flux studies by simultaneously measuring primary GHG species -- N2O, CH4, CO2 and H2O. In this study, Picarro partners with the ARS USDA Soil & Water Management Research Unit (R. Venterea, St. Paul), to examine the degree to which the high-precision, high-frequency Picarro analyzer allows for much shorter DPs periods in chamber-based flux analysis, and, in theory, less chamber-induced suppression of the soil

  15. Climatology of urban regional systems

    NASA Technical Reports Server (NTRS)

    Pease, R. W.

    1970-01-01

    The combining of remote sensing technologies to urban-regional energy climatology is studied. It was found to be three dimensional with a mosaic urban surface, each smaller surface with its own radiant and thermal properties. Urban patterns of radiant exchange were found to be constantly changing during diurnal and annual cycles. Results were derived from Barbados data using remote methods for monitoring and mapping radiation. Isoline maps of terrestrial radiation patterns were made generalizing the minute patterns of the scan image.

  16. Quantum reaction rate from higher derivatives of the thermal flux-flux autocorrelation function at time zero.

    PubMed

    Ceotto, Michele; Yang, Sandy; Miller, William H

    2005-01-22

    A quantum theory of thermal reaction rates is presented which may be viewed as an extension of the recently developed "quantum instanton" (QI) model [W. H. Miller, Y. Zhao, M. Ceotto, and S. Yang, J. Chem. Phys. 119, 1329 (2003)]. It is based on using higher derivatives of the flux-flux autocorrelation function C(t) (as given by Miller, Schwartz, and Tromp) at t=0 to construct a short time approximation for C(t). Tests of this theory on 1d and collinear reactions, both symmetric and asymmetric, show it to be more accurate than the original QI model, giving rate constants to approximately 5% for a wide range of temperature. PMID:15740237

  17. Quantum reaction rate from higher derivatives of the thermal flux-flux autocorrelation function at time zero

    NASA Astrophysics Data System (ADS)

    Ceotto, Michele; Yang, Sandy; Miller, William H.

    2005-01-01

    A quantum theory of thermal reaction rates is presented which may be viewed as an extension of the recently developed "quantum instanton" (QI) model [W. H. Miller, Y. Zhao, M. Ceotto, and S. Yang, J. Chem. Phys. 119, 1329 (2003)]. It is based on using higher derivatives of the flux-flux autocorrelation function C(t) (as given by Miller, Schwartz, and Tromp) at t=0 to construct a short time approximation for C(t). Tests of this theory on 1d and collinear reactions, both symmetric and asymmetric, show it to be more accurate than the original QI model, giving rate constants to ˜5% for a wide range of temperature.

  18. The NEWS Water Cycle Climatology

    NASA Technical Reports Server (NTRS)

    Rodell, Matthew; Beaudoing, Hiroko Kato; L'Ecuyer, Tristan; William, Olson

    2012-01-01

    NASA's Energy and Water Cycle Study (NEWS) program fosters collaborative research towards improved quantification and prediction of water and energy cycle consequences of climate change. In order to measure change, it is first necessary to describe current conditions. The goal of the first phase of the NEWS Water and Energy Cycle Climatology project was to develop "state of the global water cycle" and "state of the global energy cycle" assessments based on data from modern ground and space based observing systems and data integrating models. The project was a multi-institutional collaboration with more than 20 active contributors. This presentation will describe the results of the water cycle component of the first phase of the project, which include seasonal (monthly) climatologies of water fluxes over land, ocean, and atmosphere at continental and ocean basin scales. The requirement of closure of the water budget (i.e., mass conservation) at various scales was exploited to constrain the flux estimates via an optimization approach that will also be described. Further, error assessments were included with the input datasets, and we examine these in relation to inferred uncertainty in the optimized flux estimates in order to gauge our current ability to close the water budget within an expected uncertainty range.

  19. HNO 3 fluxes to a deciduous forest derived using gradient and REA methods

    NASA Astrophysics Data System (ADS)

    Pryor, S. C.; Barthelmie, R. J.; Jensen, B.; Jensen, N. O.; Sørensen, L. L.

    Summertime nitric acid concentrations over a deciduous forest in the midwestern United States are reported, which range between 0.36 and 3.3 μg m -3. Fluxes to the forest are computed using the relaxed eddy accumulation technique and gradient methods. In accord with previous studies, the results indicate substantial uncertainties in the gradient-based calculations. The relaxed eddy accumulation (REA) derived fluxes are physically reasonable and are shown to be of similar magnitude to dry deposition estimates from gradient sampling. The REA derived mean deposition velocity is approximately 3 cm s -1, which is also comparable to growing season estimates derived by Meyers et al. for a similar deciduous forest. Occasional inverted concentration gradients and fluxes are observed but most are not statistically significant. Data are also presented that indicate substantial through canopy penetration of nitric acid.

  20. Higher order treatment on temporal derivative of angular flux for time-dependent MOC

    SciTech Connect

    Tsujita, K.; Endo, T.; Yamamoto, A.; Kamiyama, Y.; Kirimura, K.

    2013-07-01

    A new kinetic analysis method, whose angular dependence of temporal derivative for angular flux is accurately treated within practical memory requirement, is proposed. The method of characteristics (MOC) is being widely used for reactor analysis thanks to the advances of numerical algorithms and computer hardware. However, the computational resources, i.e., the memory capacity, can be still a crucial problem for rigorous kinetic calculations using MOC. In the straightforward approach for kinetic calculation using MOC, the segment-averaged angular fluxes should be stored on the memory in order to explicitly calculate the temporal derivative of the angular flux, which would require huge memory. Thus, in the conventional kinetic calculation code using MOC, the temporal derivative of the angular flux has been approximated as angularly isotropic in order to reduce the memory requirement (isotropic assumption). However, the approximation error caused by the conventional isotropic assumption has not been thoroughly and quantitatively investigated so far and an accurate kinetic calculation method, which can quantitatively estimate the above approximation error within practical memory storage, has not been developed. The present study tries to address this issue with a newly developed approach. Effect of the approximate treatment for the temporal derivative of angular flux is evaluated through benchmark calculations. (authors)

  1. Climatology of precipitating convective clouds in ERA-Interim derived from the Emanuel and Živković-Rothman parameterisation scheme

    NASA Astrophysics Data System (ADS)

    Philipp, Anne; Seibert, Petra

    2016-04-01

    The convective parameterisation scheme of Emanuel and Živković-Rothman (1999) was designed to represent cumulus convection with a special focus on convective water fluxes. This scheme is implemented in the Lagrangian particle transport and dispersion model FLEXPART (FLEXible PARTicle dispersion model, http://flexpart.eu) to calculate a redistribution matrix used for the transport simulation. In order to improve the wet scavenging through convective clouds in this model, we are statistically evaluating a global data set of cloud base and cloud top heights of precipitating clouds derived from the EZ99 scheme and based on ECMWF's ERA-Interim data. They have a spectral resolution of about 80 km and 60 vertical levels available every 6 hours. The results will be evaluated as a function of season and geographical region.

  2. Diurnal variation climatology of short-lived at atmospheric compositions (ClO, BrO, HO2 and HOCl) derived from SMILES NICT data

    NASA Astrophysics Data System (ADS)

    Kreyling, Daniel; Sagawa, Hideo; Kasai, Yasuko

    2013-04-01

    We present a diurnal variation climatology for short-lived at atmospheric compositions, such as ClO, BrO, HO2 and HOCl, as well as for longer life time species, like O3 and HCl from observations of unprecedented sensitivity with the Superconducting SubMIllimeter wave Limb-Emission Sounder (SMILES), which is installed on the Japanese Experiment Module (JEM) at the International Space Station (ISS). With its non sun synchronous orbit, SMILES measurements comprise observations at all local times. The target altitude range is between lower stratosphere and mesopause. Differences in diurnal variation chemistry of strato-, and mesospheric BrO and ClO of the diurnal climatology are presented. The data employed is produced by the SMILES level 2 retrieval algorithm version 2.1.5 at the National Institute of Information and Communications Technology (NICT). The SMILES climatology data sets are available via the SMILES data distribution homepage in NICT at https://smiles-p6.nict.go.jp/products/research_latitude-longitude.jsf

  3. Estimating sensible heat flux in agricultural screenhouses by the flux-variance and half-order time derivative methods

    NASA Astrophysics Data System (ADS)

    Achiman, Ori; Mekhmandarov, Yonatan; Pirkner, Moran; Tanny, Josef

    2016-04-01

    Previous studies have established that the eddy covariance (EC) technique is reliable for whole canopy flux measurements in agricultural crops covered by porous screens, i.e., screenhouses. Nevertheless, the eddy covariance technique remains difficult to apply in the farm due to costs, operational complexity, and post-processing of data - thereby inviting alternative techniques to be developed. The subject of this research was estimating the sensible heat flux by two turbulent transport techniques, namely, Flux-Variance (FV) and Half-order Time Derivative (HTD) whose instrumentation needs and operational demands are not as elaborate as the EC. The FV is based on the standard deviation of high frequency temperature measurements and a similarity constant CT. The HTD method requires mean air temperature and air velocity data. Measurements were carried out in two types of screenhouses: (i) a banana plantation in a light shading (8%) screenhouse; (ii) a pepper crop in a dense insect-proof (50-mesh) screenhouse. In each screenhouse an EC system was deployed for reference and high frequency air temperature measurements were conducted using miniature thermocouples installed at several levels to identify the optimal measurement height. Quality control analysis showed that turbulence development and flow stationarity conditions in the two structures were suitable for flux measurements by the EC technique. Energy balance closure slopes in the two screenhouses were larger than 0.71, in agreement with results for open fields. Regressions between sensible heat flux measured by EC and estimated by FV resulted with CT values that were usually larger than 1, the typical value for open field. In both shading and insect-proof screenhouses the CT value generally increased with height. The optimal measurement height, defined as the height with maximum R2 of the regression between EC and FV sensible heat fluxes, was just above the screen. CT value at optimal height was 2.64 and 1.52 for

  4. Quantifying the impacts of an updated global dimethyl sulfide climatology on cloud microphysics and aerosol radiative forcing

    NASA Astrophysics Data System (ADS)

    Mahajan, Anoop S.; Fadnavis, Suvarna; Thomas, Manu A.; Pozzoli, Luca; Gupta, Smrati; Royer, Sarah-Jeanne; Saiz-Lopez, Alfonso; Simó, Rafel

    2015-03-01

    One of the critical parameters in assessing the global impacts of dimethyl sulfide (DMS) on cloud properties and the radiation budget is the estimation of phytoplankton-induced ocean emissions, which are derived from prescribed, climatological surface seawater DMS concentrations. The most widely used global ocean DMS climatology was published 15 years ago and has recently been updated using a much larger database of observations. The updated climatology displays significant differences in terms of the global distribution and regional monthly averages of sea surface DMS. In this study, we use the ECHAM5-HAMMOZ aerosol-chemistry-climate general circulation model to quantify the influence of the updated DMS climatology in computed atmospheric properties, namely, the spatial and temporal distributions of atmospheric DMS concentration, sulfuric acid concentration, sulfate aerosols, number of activated aerosols, cloud droplet number concentration, and the aerosol radiative forcing at the top of the atmosphere. Significant differences are observed for all the modeled variables. Comparison with observations of atmospheric DMS and total sulfate also shows that in places with large DMS emissions, the updated climatology shows a better match with the observations. This highlights the importance of using the updated climatology for projecting future impacts of oceanic DMS emissions, especially considering that the relative importance of the natural sulfur fluxes is likely to increase due to legislation to "clean up" anthropogenic emissions. The largest estimated differences are in the Southern Ocean, Indian Ocean, and parts of the Pacific Ocean, where the climatologies differ in seasonal concentrations over large geographical areas. The model results also indicate that the former DMS climatology underestimated the effect of DMS on the globally averaged annual aerosol radiative forcing at the top of the atmosphere by about 20%.

  5. Climatology of the Low-Level Jet East of the Andes as Derived from the NCEP NCAR Reanalyses: Characteristics and Temporal Variability.

    NASA Astrophysics Data System (ADS)

    Marengo, Jose A.; Soares, Wagner R.; Saulo, Celeste; Nicolini, Matilde

    2004-06-01

    A climatology of the South American low-level jet east of the Andes (SALLJ) is developed using the 1950 2000 circulation and moisture fields from the NCEP NCAR reanalyses and available upper-air observations made in Bolivia and Paraguay since 1998. Upper- and low-level circulation fields were derived for seasonal means and SALLJ composites during the warm and cold seasons. The Bonner criterion 1 was applied for sites in central Bolivia and downstream near northern Paraguay, to determine the spatial and temporal characteristics of the SALLJ. On the circulation characteristics, SALLJ composites during the warm season show the enhanced low-level meridional moisture transport coming from equatorial South America as well as an upper-level wave train emanating from the west Pacific propagating toward South America. The intensification of the warm season SALLJ follows the establishment of an upper-level ridge over southern Brazil and a trough over most of Argentina. The circulation anomalies at upper and lower levels suggest that the intensification of the SALLJ would lead to an intensification of the South Atlantic convergence zone (SACZ) later on and to the penetration of cold fronts with an area of enhanced convection ahead at the exit region of the SALLJ.Regarding the time variability, the SALLJ seems to occur all year long, bringing tropical moist air masses from the Amazon into southern Brazil northern Argentina more frequently in the warm season, and bringing tropical maritime air, which is less humid than the tropical air masses coming from the subtropical Atlantic high, more frequently during the cold season. SALLJs are detected mostly during the warm season to the north of 20°S, while to the south the SALLJs seem to occur all year long. The diurnal cycle shows that SALLJs are more frequent and intense between 0600 and 1200 UTC for the warm season north of 20°S, while at the region downstream the maximum is detected between 0000 and 0600 UTC during the cold

  6. SPARC Intercomparison of Middle Atmosphere Climatologies

    NASA Technical Reports Server (NTRS)

    Randel, William; Fleming, Eric; Geller, Marvin; Hamilton, Kevin; Karoly, David; Ortland, Dave; Pawson, Steve; Swinbank, Richard; Udelhofen, Petra

    2002-01-01

    This atlas presents detailed incomparisons of several climatological wind and temperature data sets which cover the middle atmosphere (over altitudes approx. 10-80 km). A number of middle atmosphere climatologies have been developed in the research community based on a variety of meteorological analyses and satellite data sets. Here we present comparisons between these climatological data sets for a number of basic circulation statistics, such as zonal mean temperature, winds and eddy flux statistics. Special attention is focused on tropical winds and temperatures, where large differences exist among separate analyses. We also include comparisons between the global climatologies and historical rocketsonde wind and temperature measurements, and also with more recent lidar temperature data. These comparisons highlight differences and uncertainties in contemporary middle atmosphere data sets, and allow biases in particular analyses to be isolated. In addition, a brief atlas of zonal mean temperature and wind statistics is provided to highlight data availability and as a quick-look reference. This technical report is intended as a companion to the climatological data sets held in archive at the SPARC Data Center (http://www.sparc.sunysb.edu).

  7. On the heat flux vector for flowing granular materials--part II: derivation and special cases

    SciTech Connect

    Massoudi, Mehrdad

    2006-09-10

    Heat transfer plays a major role in the processing of many particulate materials. The heat flux vector is commonly modelled by the Fourier's law of heat conduction and for complex materials such as non-linear fluids, porous media, or granular materials, the coefficient of thermal conductivity is generalized by assuming that it would depend on a host of material and kinematical parameters such as temperature, shear rate, porosity or concentration, etc. In Part I, we will give a brief review of the basic equations of thermodynamics and heat transfer to indicate the importance of the modelling of the heat flux vector. We will also discuss the concept of effective thermal conductivity (ETC) in granular and porous media. In Part II, we propose and subsequently derive a properly frame-invariant constitutive relationship for the heat flux vector for a (single phase) flowing granular medium. Standard methods in continuum mechanics such as representation theorems and homogenization techniques are used. It is shown that the heat flux vector in addition to being proportional to the temperature gradient (the Fourier's law), could also depend on the gradient of density (or volume fraction), and D (the symmetric part of the velocity gradient) in an appropriate manner. The emphasis in this paper is on the idea that for complex non-linear materials it is the heat flux vector which should be studied; obtaining or proposing generalized form of the thermal conductivity is not always appropriate or sufficient.

  8. Heat and moisture flux modeling of the FIFE grassland canopy aided by satellite derived canopy variables

    NASA Technical Reports Server (NTRS)

    Smith, Eric A.; Crosson, William L.; Cooper, Harry J.; Weng, Heng-Yi

    1990-01-01

    Satellite data corresponding to radiance variables are used to derive three canopy properties which describe slowly modulating boundary conditions of the interface between the biosphere and the atmosphere. The canopy properties are key factors in the regulation of heat and moisture transfer and are found to be radiance patterns within a homogeneous ecosystem. The physical modeling technique is enhanced by the satellite data, and the surface fluxes are represented more accurately in the resulting biosphere-interface model.

  9. Climatology of globally averaged thermospheric mass density

    NASA Astrophysics Data System (ADS)

    Emmert, J. T.; Picone, J. M.

    2010-09-01

    We present a climatological analysis of daily globally averaged density data, derived from orbit data and covering the years 1967-2007, along with an empirical Global Average Mass Density Model (GAMDM) that encapsulates the 1986-2007 data. The model represents density as a function of the F10.7 solar radio flux index, the day of year, and the Kp geomagnetic activity index. We discuss in detail the dependence of the data on each of the input variables, and demonstrate that all of the terms in the model represent consistent variations in both the 1986-2007 data (on which the model is based) and the independent 1967-1985 data. We also analyze the uncertainty in the results, and quantify how the variance in the data is apportioned among the model terms. We investigate the annual and semiannual variations of the data and quantify the amplitude, height dependence, solar cycle dependence, and interannual variability of these oscillatory modes. The auxiliary material includes Fortran 90 code for evaluating GAMDM.

  10. Climatology of the East Antarctic ice sheet (100°E to 140°E) derived from automatic weather stations

    NASA Astrophysics Data System (ADS)

    Allison, Ian; Wendler, Gerd; Radok, Uwe

    1993-05-01

    A decade ago, automatic weather stations (AWS) were placed in remote areas of Antarctica where little or no information on the meteorological conditions was available. These stations report to the ARGOS data collection system onboard polar orbiting satellites of the NOAA series. The Australian National Antarctic Research Expeditions (ANARE) and the United States Antarctic Research Program (USARP) of the National Science Foundation (with logistic support from the French Expéditions Polaires Françaises (EPF)) have built up two AWS data nets in East Antarctica. There are a total of 16 stations in the area 55°-145°E and 65°-75°S, stretching from sea level to above 3000 m altitude. The records of 10 of these stations are sufficiently long to be adequate for a climatological study of the basic parameters of surface temperature, pressure, and wind and have been used in this study. The station data were reduced to a common format and interpreted jointly to describe the broad-scale climatic features of the ice sheet. Climatological results include (1) an absolute lowest minimum temperature of -84.6°C at Dome C; (2) no minimum below -40°C at D10 near the coast; (3) a "coreless" winter temperature regime, without seasonal temperature trends for 6 months, at all stations; (4) mean surface wind speeds increasing to maxima near, rather than at, the coast; (5) high directional constancy in all seasons, with directions closer to the fall line in winter and during night hours than in summer and during day hours; (7) a distinct semiannual pressure variation with a main minimum in spring (September) and a secondary minimum in autumn (March); and (8) interrelationships among surface temperature, pressure, and wind related to the ice sheet topography.

  11. Vertical velocities and momentum fluxes derived from wind measurements in the dusk auroral oval

    NASA Technical Reports Server (NTRS)

    Larsen, M. F.; Mikkelsen, I. S.

    1990-01-01

    Results are presented on a chemical release experiment carried out on March 20, 1985 in connection with NASA's Cooperative Observations of Polar Electrodynamics I campaign. Simultaneous neutral wind measurements in E region were carried out at three separate locations over a triangular region with sides of about 150 km in the dusk auroral oval, and the three wind profiles were used to calculate values of divergence and vorticity over the area. The vertical velocity over the hight range was calculated using the mass continuity equation, and the instantaneous vertical momentum fluxes in the E region were derived using the combination of horizontal-wind measurements and calculated vertical velocities. Results show that there is strong coupling between layers in the E region and that the momentum-flux-induced accelerations are at least comparable in magnitude to the pressure gradient and Coriolis force accelerations.

  12. Heat conduction in nanoscale materials: a statistical-mechanics derivation of the local heat flux.

    PubMed

    Li, Xiantao

    2014-09-01

    We derive a coarse-grained model for heat conduction in nanoscale mechanical systems. Starting with an all-atom description, this approach yields a reduced model, in the form of conservation laws of momentum and energy. The model closure is accomplished by introducing a quasilocal thermodynamic equilibrium, followed by a linear response approximation. Of particular interest is the constitutive relation for the heat flux, which is expressed nonlocally in terms of the spatial and temporal variation of the temperature. Nanowires made of copper and silicon are presented as examples. PMID:25314400

  13. Thermal performance of multilayer insulation. I - Derivation of a prediction-based heat-flux equation

    NASA Astrophysics Data System (ADS)

    Amano, Toshiyuki

    1993-07-01

    A prediction-based equation for heat flux through a multilayer insulator was derived from comparison of experimental results between room temperature and liquid nitrogen temperature. The employed multilayer insulator was a laminated material with a polyester net inserted between aluminized Mylar films. The prediction equation consists of one thermal radiation and two thermal conduction terms. The first conduction term is that of ordinary thermal contact conductance. The second conduction term depends on the self-compression of the multilayer insulation. The predicted values resulting from the obtained equation coincided fairly well with measured values.

  14. Antarctic Meteorology and Climatology

    NASA Astrophysics Data System (ADS)

    King, J. C.; Turner, J.

    1997-07-01

    This book is a comprehensive survey of the climatology and meteorology of Antarctica. The first section of the book reviews the methods by which we can observe the Antarctic atmosphere and presents a synthesis of climatological measurements. In the second section, the authors consider the processes that maintain the observed climate, from large-scale atmospheric circulation to small-scale processes. The final section reviews our current knowledge of the variability of Antarctic climate and the possible effects of "greenhouse" warming. The authors stress links among the Antarctic atmosphere, other elements of the Antarctic climate system (oceans, sea ice and ice sheets), and the global climate system. This volume will be of greatest interest to meteorologists and climatologists with a specialized interest in Antarctica, but it will also appeal to researchers in Antarctic glaciology, oceanography and biology. Graduates and undergraduates studying physical geography, and the earth, atmospheric and environmental sciences will find much useful background material in the book.

  15. A charge-charge flux-dipole flux decomposition of the dipole moment derivatives and infrared intensities of the AB 3 (A = N, P; B = H, F) molecules

    NASA Astrophysics Data System (ADS)

    César, Paulo H.; Faria, Sérgio H. D. M.; da Silva, João V.; Haiduke, R. L. A.; Bruns, Roy E.

    2005-10-01

    The quantum theory of atoms in molecules (AIM) has been used to decompose dipole moment derivatives and fundamental infrared intensities of the AB 3 (A = N,P; B = H,F) molecules into charge-charge flux-dipole flux (CCFDF) contributions. Calculations were carried out at the MP2(FC)/6-311++G(3d,3p) level. Infrared intensities calculated from the AIM atomic charges and atomic dipoles are within 13.8 km mol -1 of the experimental values not considering the NH 3 and PH 3 stretching vibrations for which the experimental bands are severely overlapped. Group V atomic dipoles are very important in determining the molecular dipole moments of NF 3, PH 3 and PF 3 although the atomic charges account for almost all of the NH 3 molecular moment. Dipole fluxes on the Group V atom are important in determining the stretching band intensities of all molecules whereas they make small contributions to the bending mode intensities. Consideration of dipole flux contributions from the terminal atoms must also be made for accurately describing the intensities of all these molecules. As expected from a simple bond moment model, charge contributions dominate for most of the NH 3, NF 3, and PF 3 dipole moment derivatives and intensities. Charge flux and dipole flux contributions are very substantial for all the PH 3 vibrations, cancelling each other for the stretching modes and reinforcing one another for the bending modes.

  16. A heavy rainfall sounding climatology over Gauteng, South Africa, using self-organising maps

    NASA Astrophysics Data System (ADS)

    Dyson, Liesl L.

    2015-12-01

    The daily weather at a particular place is largely influenced by the synoptic circulation and thermodynamic profile of the atmosphere. Heavy rainfall occurs from a particular subset of synoptic and thermodynamic states. Baseline climatologies provide objective information on heavy rainfall-producing circulation patterns and thermodynamic variables. This is how climatologically large or extreme values associated with heavy rainfall are identified. The aim of this research is to provide a heavy rainfall sounding climatology in austral summer over Gauteng, South Africa, using self-organising maps (SOMs). The results show that the SOM captures the intra-seasonal variability of heavy rainfall soundings by clearly distinguishing between the atmospheric conditions on early summer (October-December) and late summer (January-March) heavy rainfall days. Conditions associated with heavy early summer rainfall are large vertical wind shear and conditional instability, while the atmosphere is drier and cooler than when heavy rainfall occurs in late summer. Late summer heavy rainfall conditions are higher convective instability and small vertical wind shear values. The SOM climatology shows that some heavy rainfall days occur in both early and late summer when large-scale synoptic weather systems cause strong near-surface moisture flux and large values of wind shear. On these days, both the conditional and convective instability of the atmosphere are low and heavy rainfall results from the strong synoptic forcing. In contrast, heavy rainfall also occurs on days when synoptic circulation is not very favourable and the air is relatively dry, but the atmosphere is unstable with warm surface conditions and heavy rainfall develops from local favourable conditions. The SOM climatology provides guidelines to critical values of sounding-derived parameters for all these scenarios.

  17. First space-based derivation of the global atmospheric methanol emission fluxes

    NASA Astrophysics Data System (ADS)

    Stavrakou, T.; Guenther, A.; Razavi, A.; Clarisse, L.; Clerbaux, C.; Coheur, P.-F.; Hurtmans, D.; Karagulian, F.; de Mazière, M.; Vigouroux, C.; Amelynck, C.; Schoon, N.; Laffineur, Q.; Heinesch, B.; Aubinet, M.; Rinsland, C.; Müller, J.-F.

    2011-05-01

    significant error reductions achieved by the optimization concern the derived biogenic emissions over the Amazon and over the Former Soviet Union. The robustness of the derived fluxes to changes in convective updraft fluxes, in methanol removal processes, and in the choice of the biogenic a priori inventory is assessed through sensitivity inversions. Detailed comparisons of the model with a number of aircraft and surface observations of methanol, as well as new methanol measurements in Europe and in the Reunion Island show that the satellite-derived methanol emissions improve significantly the agreement with the independent data, giving thus credence to the IASI dataset.

  18. A simple calculation algorithm to separate high-resolution CH4 flux measurements into ebullition and diffusion-derived components

    NASA Astrophysics Data System (ADS)

    Hoffmann, Mathias; Schulz-Hanke, Maximilian; Garcia Alba, Joana; Jurisch, Nicole; Hagemann, Ulrike; Sachs, Torsten; Sommer, Michael; Augustin, Jürgen

    2016-04-01

    Processes driving methane (CH4) emissions in wetland ecosystems are highly complex. Especially, the separation of CH4 emissions into ebullition and diffusion derived flux components, a perquisite for the mechanistic process understanding and identification of potential environmental driver is rather challenging. We present a simple calculation algorithm, based on an adaptive R-script, which separates open-water, closed chamber CH4 flux measurements into diffusion- and ebullition-derived components. Hence, flux component specific dynamics are revealed and potential environmental driver identified. Flux separation is based on a statistical approach, using ebullition related sudden concentration changes obtained during high resolution CH4 concentration measurements. By applying the lower and upper quartile ± the interquartile range (IQR) as a variable threshold, diffusion dominated periods of the flux measurement are filtered. Subsequently, flux calculation and separation is performed. The algorithm was verified in a laboratory experiment and tested under field conditions, using flux measurement data (July to September 2013) from a flooded, former fen grassland site. Erratic ebullition events contributed 46% to total CH4 emissions, which is comparable to values reported by literature. Additionally, a shift in the diurnal trend of diffusive fluxes throughout the measurement period, driven by the water temperature gradient, was revealed.

  19. Assessing the Uncertainty of Land Surface Fluxes Derived from Operational Analyses

    NASA Technical Reports Server (NTRS)

    Bosilovich, Michael G.; Mocko, David

    2009-01-01

    Operational numerical weather prediction systems assimilate tremendous amounts of observations to produce global analyses of the atmospheric states. Since the systems include significant contributions from the model components, physical fields, such as the turbulent heat fluxes, can also be derived. However, the physical fields are indirectly constrained by the data assimilation, and so subject to uncertainty in the model parameterizations. Recently, 10 international operational analyses have been collected and reprocessed through the Coordinated Enhanced. Observing Period (CEOP). Comparisons against independent observations (global precipitation and outgoing longwave radiation) show that while there is significant range of the individual analyses, the ensemble of analyses provide data closest the observations. Here, we evaluate the collection of land surface turbulent heat fluxes. The data are available for Oct 2002 - Dec 2004, at 6 hourly, daily and monthly intervals. An ensemble mean and its variance have been computed. we will analyze the range of analysis results at daily and seasonal time scales, and where possible compare with existing observations.

  20. Wnt directs the endosomal flux of LDL-derived cholesterol and lipid droplet homeostasis

    PubMed Central

    Scott, Cameron C; Vossio, Stefania; Vacca, Fabrizio; Snijder, Berend; Larios, Jorge; Schaad, Olivier; Guex, Nicolas; Kuznetsov, Dmitry; Martin, Olivier; Chambon, Marc; Turcatti, Gerardo; Pelkmans, Lucas; Gruenberg, Jean

    2015-01-01

    The Wnt pathway, which controls crucial steps of the development and differentiation programs, has been proposed to influence lipid storage and homeostasis. In this paper, using an unbiased strategy based on high-content genome-wide RNAi screens that monitored lipid distribution and amounts, we find that Wnt3a regulates cellular cholesterol. We show that Wnt3a stimulates the production of lipid droplets and that this stimulation strictly depends on endocytosed, LDL-derived cholesterol and on functional early and late endosomes. We also show that Wnt signaling itself controls cholesterol endocytosis and flux along the endosomal pathway, which in turn modulates cellular lipid homeostasis. These results underscore the importance of endosome functions for LD formation and reveal a previously unknown regulatory mechanism of the cellular programs controlling lipid storage and endosome transport under the control of Wnt signaling. PMID:25851648

  1. The Global Precipitation Climatology Centre (GPCC) - in situ observation based precipitation climatology on regional and global scale

    NASA Astrophysics Data System (ADS)

    Fuchs, T.; Schneider, U.; Rudolf, B.

    2009-04-01

    The Global Precipitation Climatology Centre (GPCC, http://gpcc.dwd.de) provides global monthly precipitation analyses for monitoring and research of the earth's climate. The centre is a German contribution to the World Climate Research Programme (WCRP), to the Global Climate Observing System (GCOS), and to the Global Earth Observation System of Systems (GEOSS). It contributes to water resources assessments, flood and drought monitoring, climate variability and trend analyses. GPCC published in year 2008 a new global precipitation climatology as well as a reanalysis of its full data base for all months of the period 1901-2007. The GPCC data base comprises monthly precipitation totals from more than 70 000 different stations in the world. It produces gridded data sets of monthly precipitation on the earth's land surface derived from raingauge based observation data. Intensive quality control of observation data and station metadata ensures a high analysis quality. The different GPCC products are adjusted to different user needs. It routinely produces 2 near real-time precipitation monitoring products. Its 2 non real-time products are updated at irregular time intervals after significant updates of its observation station database. All GPCC products can be visualised and accessed free of charge via Internet from http://gpcc.dwd.de. The GPCC First Guess Product of the monthly precipitation anomaly is based on synoptic weather reports (SYNOP) from about 6,300 stations worldwide received near real-time via the WMO Global Telecommunication System (GTS). The product is available within 5 days after end of an observation month. Main application purpose is near real-time drought monitoring. The product uses since mid 2008 the new GPCC monthly precipitation climatology as analysis background. Spatial product resolution: 1.0° and 2.5°. The GPCC Monitoring Product of monthly precipitation is based on SYNOP and monthly CLIMAT reports received near real-time via GTS from about

  2. Situational Lightning Climatologies

    NASA Technical Reports Server (NTRS)

    Bauman, William; Crawford, Winifred

    2010-01-01

    Research has revealed distinct spatial and temporal distributions of lightning occurrence that are strongly influenced by large-scale atmospheric flow regimes. It was believed there were two flow systems, but it has been discovered that actually there are seven distinct flow regimes. The Applied Meteorology Unit (AMU) has recalculated the lightning climatologies for the Shuttle Landing Facility (SLF), and the eight airfields in the National Weather Service in Melbourne (NWS MLB) County Warning Area (CWA) using individual lightning strike data to improve the accuracy of the climatologies. The software determines the location of each CG lightning strike with 5-, 10-, 20-, and 30-nmi (.9.3-, 18.5-, 37-, 55.6-km) radii from each airfield. Each CG lightning strike is binned at 1-, 3-, and 6-hour intervals at each specified radius. The software merges the CG lightning strike time intervals and distance with each wind flow regime and creates probability statistics for each time interval, radii, and flow regime, and stratifies them by month and warm season. The AMU also updated the graphical user interface (GUI) with the new data.

  3. Intercomparison of Satellite Derived Gravity Time Series with Inferred Gravity Time Series from TOPEX/POSEIDON Sea Surface Heights and Climatological Model Output

    NASA Technical Reports Server (NTRS)

    Cox, C.; Au, A.; Klosko, S.; Chao, B.; Smith, David E. (Technical Monitor)

    2001-01-01

    The upcoming GRACE mission promises to open a window on details of the global mass budget that will have remarkable clarity, but it will not directly answer the question of what the state of the Earth's mass budget is over the critical last quarter of the 20th century. To address that problem we must draw upon existing technologies such as SLR, DORIS, and GPS, and climate modeling runs in order to improve our understanding. Analysis of long-period geopotential changes based on SLR and DORIS tracking has shown that addition of post 1996 satellite tracking data has a significant impact on the recovered zonal rates and long-period tides. Interannual effects such as those causing the post 1996 anomalies must be better characterized before refined estimates of the decadal period changes in the geopotential can be derived from the historical database of satellite tracking. A possible cause of this anomaly is variations in ocean mass distribution, perhaps associated with the recent large El Nino/La Nina. In this study, a low-degree spherical harmonic gravity time series derived from satellite tracking is compared with a TOPEX/POSEIDON-derived sea surface height time series. Corrections for atmospheric mass effects, continental hydrology, snowfall accumulation, and ocean steric model predictions will be considered.

  4. QTAIM charge-charge flux-dipole flux interpretation of electronegativity and potential models of the fluorochloromethane mean dipole moment derivatives.

    PubMed

    Silva, Arnaldo F; da Silva, João V; Haiduke, R L A; Bruns, Roy E

    2011-11-17

    Infrared fundamental vibrational intensities and quantum theory atoms in molecules (QTAIM) charge-charge flux-dipole flux (CCFDF) contributions to the polar tensors of the fluorochloromethanes have been calculated at the QCISD/cc-pVTZ level. A root-mean-square error of 20.0 km mol(-1) has been found compared to an experimental error estimate of 14.4 and 21.1 km mol(-1) for MP2/6-311++G(3d,3p) results. The errors in the QCISD polar tensor elements and mean dipole moment derivatives are 0.059 e when compared with the experimental values. Both theoretical levels provide results showing that the dynamical charge and dipole fluxes provide significant contributions to the mean dipole moment derivatives and tend to be of opposite signs canceling one another. Although the experimental mean dipole moment derivative values suggest that all the fluorochloromethane molecules have electronic structures consistent with a simple electronegativity model with transferable atomic charges for their terminal atoms, the QTAIM/CCFDF models confirm this only for the fluoromethanes. Whereas the fluorine atom does not suffer a saturation effect in its capacity to drain electronic charge from carbon atoms that are attached to other fluorine and chlorine atoms, the zero flux electronic charge of the chlorine atom depends on the number and kind of the other substituent atoms. Both the QTAIM carbon charges (r = 0.990) and mean dipole moment derivatives (r = 0.996) are found to obey Siegbahn's potential model for carbon 1s electron ionization energies at the QCISD/cc-pVTZ level. The latter is a consequence of the carbon mean derivatives obeying the electronegativity model and not necessarily to their similarities with atomic charges. Atomic dipole contributions to the neighboring atom electrostatic potentials of the fluorochloromethanes are found to be of comparable size to the atomic charge contributions and increase the accuracy of Siegbahn's model for the QTAIM charge model results

  5. Development and application of Labrador Sea climatologies

    NASA Astrophysics Data System (ADS)

    Cetin, Nilgun

    2007-05-01

    Two yearly climatologies of the Labrador Sea are developed. One is based on the traditional geopotential coordinates, and the other employs isopycnal coordinates in the vertical. The analysis of the results show that the isopycnal climatology has more skill at describing the mean state of the Labrador Sea, without smoothing out important flow features such as strong boundary currents and fronts. Seasonal climatologies based on the isopycnal coordinates in the vertical are also developed to study seasonal variability of the Labrador Sea hydrography and freshwater and heat fluxes. The greatest seasonal variability is observed in winter, the season in which deep convective overturning takes place. By using the objective analysis technique which successfully represented the dynamics of the Labrador Sea, a pseudo time-series of water properties is developed to study their inter-annual variability. The contribution of the West Greenland Current to the interior Labrador Sea freshwater budget is found to be greater than that of the Labrador Current, even though the Labrador Current has a larger freshwater content. Diagnostic calculations show that the Labrador Current flows southward mostly parallel to the isobaths without much of its fresher waters ever crossing into the interior Labrador Sea.

  6. An atomic charge-charge flux-dipole flux atom-in-molecule decomposition for molecular dipole-moment derivatives and infrared fundamental intensities.

    PubMed

    Haiduke, Roberto L A; Bruns, Roy E

    2005-03-24

    The molecular dipole moment and its derivatives are determined from atomic charges, atomic dipoles, and their fluxes obtained from AIM formalism and calculated at the MP2(FC)/6-311++G(3d,3p) level for 16 molecules: 6 diatomic hydrides, CO, HCN, OCS, CO2, CS2, C2H2, C2N2, H2O, H2CO, and CH4. Root-mean-square (rms) errors of 0.052 D and 0.019 e are found for the dipole moments and their derivatives calculated using AIM parameters when compared with those obtained directly from the MP2(FC)/6-311++G(3d,3p) calculations and 0.097 D and 0.049 e when compared to the experimental values. The major deviations occur for the NaH, HF, and H2O molecules. Parallel polar tensor elements for the diatomic and linear polyatomic molecules, except H2, HF, LiH, and NaH, have values resulting from cancellations of substantial contributions from atomic charge fluxes and atomic dipole fluxes. These fluxes have a large negative correlation coefficient, -0.97. IR fundamental intensity sums for CO, HCN, OCS, CO2, CS2, C2H2, C2N2, H2CO, and CH4 calculated using AIM charges, charge fluxes, and atomic dipole fluxes have rms errors of 14.9 km mol(-1) when compared with sums calculated directly from the molecular wave function and 36.2 km mol(-1) relative to experimental values. The classical model proposed here to calculate dipole-moment derivatives is compared with the charge-charge flux-overlap model long used by spectroscopists for interpreting IR vibrational intensities. The utility of the AIM atomic charges and dipoles was illustrated by calculating the forces exerted on molecules by a charged particle. AIM quantities were able to reproduce forces due to a +0.1 e particle over a 3-8-A separation range for the CO and HF molecules in collinear and perpendicular arrangements. These results show that IR intensities do contain information relevant to the study of intermolecular interactions. PMID:16833574

  7. The influence of climate on soil carbon turnover times derived from carbon flux and pool data

    NASA Astrophysics Data System (ADS)

    Khomik, M.; Reichstein, M.; Schrumpf, M.; Beer, C.; Curiel-Yuste, C. J.; Jenssens, I.; Luyssaert, S.; Subke, J.; Trumbore, S.; Wutzler, T.; Jung, M.; Lasslop, G.; Fluxnet Lathuille Synthesis Team (Cf. Www. Fluxdata. Org)

    2010-12-01

    Our understanding of the climatic controls on the rate of soil organic carbon (SOM) decomposition is still limited and greatly debated, especially the temperature sensitivity of decomposition. This lack of understanding and consensus hinders the ability to develop and improve models of soil carbon dynamics. In light of this, we used annual ecosystem carbon flux measurements and soil organic carbon stocks to derive soil carbon turnover times (TO) for a selection of eddy flux sites (FLUXNET LaThuille dataset) , following a method proposed by Sanderman et al.(2003). We then related these TO to mean annual temperatures (MAT) and found that TO decreased exponentially with increasing MAT, in accordance with Sanderman et al (2003) and other studies. However, upon closer examination, we also found that this exponential relationship was largely driven by the difference in TO between sites located in the boreal climate zone and those in the tropical, Mediterranean and temperate climates, combined. The range of computed TO values in the boreal zone was higher compared to the rest. Likewise, we also analyzed the combined effect of MAT and total annual precipitation (TAP) on TO and found that TAP was also negatively correlated to TO, although not as strongly as MAT. Similar to the response to MAT, the observed overall TAP vs TO relationship was also driven primarily by the difference in the range of TO values computed for sites from the boreal climate zone. The results of this study add to our understanding of the spatial variability of SOM controls and can be used to improve and/or direct future studies on soil carbon cycling. Sanderman, J., R. G. Amundson, and D. D. Baldocchi, Application of eddy covariance measurements to the temperature dependence of soil organic matter mean residence time, Global Biogeochem. Cycles, 17(2), 1061, doi:10.1029/2001GB001833, 2003.

  8. Combined Satellite - and ULS-Derived Sea-Ice Flux in the Weddell Sea

    NASA Technical Reports Server (NTRS)

    Drinkwater, M.; Liu, X.; Harms, S.

    2000-01-01

    Several years of daily microwave satellite ice-drift are combined with moored Upward Looking Sonar (ULS) ice-drafts into an ice volume flux record at points along a flux gate across the Weddell Sea, Antarctica.

  9. Volcanic SO2 fluxes derived from satellite data: a survey using OMI, GOME-2, IASI and MODIS

    NASA Astrophysics Data System (ADS)

    Theys, N.; Campion, R.; Clarisse, L.; Brenot, H.; van Gent, J.; Dils, B.; Corradini, S.; Merucci, L.; Coheur, P.-F.; Van Roozendael, M.; Hurtmans, D.; Clerbaux, C.; Tait, S.; Ferrucci, F.

    2013-06-01

    Sulphur dioxide (SO2) fluxes of active degassing volcanoes are routinely measured with ground-based equipment to characterize and monitor volcanic activity. SO2 of unmonitored volcanoes or from explosive volcanic eruptions, can be measured with satellites. However, remote-sensing methods based on absorption spectroscopy generally provide integrated amounts of already dispersed plumes of SO2 and satellite derived flux estimates are rarely reported. Here we review a number of different techniques to derive volcanic SO2 fluxes using satellite measurements of plumes of SO2 and investigate the temporal evolution of the total emissions of SO2 for three very different volcanic events in 2011: Puyehue-Cordón Caulle (Chile), Nyamulagira (DR Congo) and Nabro (Eritrea). High spectral resolution satellite instruments operating both in the ultraviolet-visible (OMI/Aura and GOME-2/MetOp-A) and thermal infrared (IASI/MetOp-A) spectral ranges, and multispectral satellite instruments operating in the thermal infrared (MODIS/Terra-Aqua) are used. We show that satellite data can provide fluxes with a sampling of a day or less (few hours in the best case). Generally the flux results from the different methods are consistent, and we discuss the advantages and weaknesses of each technique. Although the primary objective of this study is the calculation of SO2 fluxes, it also enables us to assess the consistency of the SO2 products from the different sensors used.

  10. Volcanic SO2 fluxes derived from satellite data: a survey using OMI, GOME-2, IASI and MODIS

    NASA Astrophysics Data System (ADS)

    Theys, N.; Campion, R.; Clarisse, L.; Brenot, H.; van Gent, J.; Dils, B.; Corradini, S.; Merucci, L.; Coheur, P.-F.; Van Roozendael, M.; Hurtmans, D.; Clerbaux, C.; Tait, S.; Ferrucci, F.

    2012-12-01

    Sulphur dioxide (SO2) fluxes of active degassing volcanoes are routinely measured with ground-based equipment to characterize and monitor volcanic activity. SO2 of unmonitored volcanoes or from explosive volcanic eruptions, can be measured with satellites. However, remote-sensing methods based on absorption spectroscopy generally provide integrated amounts of already dispersed plumes of SO2 and satellite derived flux estimates are rarely reported. Here we review a number of different techniques to derive volcanic SO2 fluxes using satellite measurements of dispersed and large-scale plumes of SO2 and investigate the temporal evolution of the total emissions of SO2 for three very different volcanic events in 2011: Puyehue-Cordón Caulle (Chile), Nyamulagira (DR Congo) and Nabro (Eritrea). High spectral resolution satellite instruments operating both in the UV-visible (OMI/Aura and GOME-2/MetOp-A) and thermal infrared (IASI/MetOp-A) spectral ranges, and multispectral satellite instruments operating in the thermal infrared (MODIS/Terra-Aqua) are used. We show that satellite data can provide fluxes with a sampling of a day or less (few hours in the best case). Generally the flux results from the different methods are consistent, and we discuss the advantages and weaknesses of each technique. Although the primary objective of this study is the calculation of SO2 fluxes, it also enables to assess the consistency of the SO2 products from the different sensors used.

  11. On Deriving Incident Auroral Particle Fluxes in the Daytime Using Combined Ground-Based Optical and Radar Measurements

    NASA Technical Reports Server (NTRS)

    Pallamraju, Duggirala; Chakrabarti, Supriya; Solomon, Stanley C.

    2011-01-01

    Particle energies and fluxes have predominantly been measured from instruments onboard satellites. In this study, we use daytime ground-based oxygen redline emission measurements, along with the ionospheric electron density, and electron temperature profiles measured from the incoherent scatter radar, and a physics-based modeling approach to derive the energy and flux of particles incident over Boston during the storm of 30 October 2003. We find that the characteristic energy and the associated flux vary between 0.07.5.7 keV and 0.5.130 mW/sq m, respectively, during the intense magnetic disturbance that brought aurora to midlatitudes. Such an approach not only offers another method to estimate the incident particle energies and fluxes but also enhances our understanding on the channels of energy deposition in the upper atmospheric region, especially during magnetic disturbances, about which database is poor.

  12. On deriving incident auroral particle fluxes in the daytime using combined ground-based optical and radar measurements

    NASA Astrophysics Data System (ADS)

    Pallamraju, Duggirala; Chakrabarti, Supriya; Solomon, Stanley C.

    2011-04-01

    Particle energies and fluxes have predominantly been measured from instruments onboard satellites. In this study, we use daytime ground-based oxygen redline emission measurements, along with the ionospheric electron density, and electron temperature profiles measured from the incoherent scatter radar, and a physics-based modeling approach to derive the energy and flux of particles incident over Boston during the storm of 30 October 2003. We find that the characteristic energy and the associated flux vary between 0.07-5.7 keV and 0.5-130 mW m-2, respectively, during the intense magnetic disturbance that brought aurora to midlatitudes. Such an approach not only offers another method to estimate the incident particle energies and fluxes but also enhances our understanding on the channels of energy deposition in the upper atmospheric region, especially during magnetic disturbances, about which database is poor.

  13. Surface-Layer Flux-Gradient Relationships over Inclined Terrain Derived from a Local Equilibrium, Turbulence Closure Model

    NASA Astrophysics Data System (ADS)

    Łobocki, Lech

    2014-03-01

    Derivation of surface-layer flux-gradient relationships from a local-equilibrium, turbulence-closure model for a forced flow over inclined terrain is presented. Results are shown as a generalization of Monin-Obukhov universal functions respesenting non-dimensional wind and temperature gradients.

  14. Combination of remote sensing data products to derive spatial climatologies of "degree days" and downscale meteorological reanalyses: application to the Upper Indus Basin

    NASA Astrophysics Data System (ADS)

    Forsythe, N. D.; Rutter, N.; Brock, B. W.; Fowler, H. J.; Blenkinsop, S.

    2014-12-01

    Lack of observations for the full range of required variables is a critical reason why many cryosphere-dominated hydrological modelling studies adopt a temperature index (degree day) approach to meltwater simulation rather than resolving the full surface energy balance. Thus spatial observations of "degree days" would be extremely useful in constraining model parameterisations. Even for models implementing a full energy balance, "degree day" observations provide a characterisation of the spatial distribution of climate inputs to the cryosphere-hydrological system. This study derives "degree days" for the Upper Indus Basin by merging remote sensing data products: snow cover duration (SCD), from MOD10A1 and land surface temperature (LST), from MOD11A1 and MYD11A1. Pixel-wise "degree days" are calculated, at imagery-dependent spatial resolution, by multiplying SCD by (above-freezing) daily LST. This is coherent with the snowpack-energy-to-runoff conversion used in temperature index algorithms. This allows assessment of the spatial variability of mass inputs (accumulated snowpack) because in nival regime areas - where complete ablation is regularly achieved - mass is the limiting constraint. The GLIMS Randolph Glacier Inventory is used to compare annual totals and seasonal timings of "degree days" over glaciated and nival zones. Terrain-classified statistics (by elevation and aspect) for the MODIS "degree-day" hybrid product are calculated to characterise of spatial precipitation distribution. While MODIS data products provide detailed spatial resolution relative to tributary catchment areas, the limited instrument record length is inadequate for assessing climatic trends and greatly limits use for hydrological model calibration and validation. While multi-decadal MODIS equivalent data products may be developed in the coming years, at present alternative methods are required for "degree day" trend analysis. This study thus investigates the use of the hybrid MODIS

  15. Comparison of ground-derived and satellite-derived surface energy fluxes from a shrub-steppe site

    SciTech Connect

    Kirkham, R.R.; Gee, G.W.; Fritschen, L.J.

    1994-03-01

    Efforts to measure evapotranspiration (ET) remotely are common in agriculture, and the application of such data to irrigation scheduling is readily apparent. Extending this methodology to arid environments is primarily of use as a mechanism for validation of ET algorithms used in large-scale watershed and global climate change modeling efforts. To facilitate testing of the remote sensing method for ET, measurements of sensible and latent heat flux were made at four sites located on the US Department of Energy`s Hanford Site using a combination of lysimeter and Bowen Ratio Energy Balance (BREB) stations. The objective was to calibrate an aerodynamic transport equation that relates sensible heat flux to radiant surface temperature, and to map sensible heat flux using Landsat data.

  16. Tornado climatology of Austria

    NASA Astrophysics Data System (ADS)

    Holzer, A. M.

    After several decades of little work, a revised tornado climatology for Austria is presented. Tornadoes seldom form in the alpine areas, however, near the eastern flanks of the Alps, favourable conditions for tornado genesis are found. Whereas in the alpine regions less than 0.3 tornadoes per 10,000 km 2 a year touch down (averaged for provinces or major parts of a province), we can count 0.9 in the greater Graz area, 1.0 in the greater Linz area and 1.2 tornadoes per 10,000 km 2 a year in the greater Vienna area, suggesting the existence of so-called tornado alleys. As these regions are the most populated areas of Austria, there is a possible population bias in the dataset. The overall average for Austria is 0.3 tornadoes per 10,000 km 2 a year. The database consists of 89 tornadoes, one landspout and six waterspouts, with a total of 96 events. The seasonal peak is in July with a maximum probability of tornadoes in the late afternoon and early evening hours. Every fifth tornado occurs in the hour after 5 p.m. The maximum intensity determined for a tornado in Austria was T7 on the TORRO-Scale (F3 on the Fujita-Scale), the most common intensity is T2 on the TORRO-Scale (F1 on the Fujita-Scale).

  17. Radon flux maps for the Netherlands and Europe using terrestrial gamma radiation derived from soil radionuclides

    NASA Astrophysics Data System (ADS)

    Manohar, S. N.; Meijer, H. A. J.; Herber, M. A.

    2013-12-01

    Naturally occurring radioactive noble gas, radon (222Rn) is a valuable tracer to study atmospheric processes and to validate global chemical transport models. However, the use of radon as a proxy in atmospheric and climate research is limited by the uncertainties in the magnitude and distribution of the radon flux density over the Earth's surface. Terrestrial gamma radiation is a useful proxy for generating radon flux maps. A previously reported radon flux map of Europe used terrestrial gamma radiation extracted from automated radiation monitoring networks. This approach failed to account for the influence of local artificial radiation sources around the detector, leading to under/over estimation of the reported radon flux values at different locations. We present an alternative approach based on soil radionuclides which enables us to generate accurate radon flux maps with good confidence. Firstly, we present a detailed comparison between the terrestrial gamma radiation obtained from the National Radiation Monitoring network of the Netherlands and the terrestrial gamma radiation calculated from soil radionuclides. Extending further, we generated radon flux maps of the Netherlands and Europe using our proposed approach. The modelled flux values for the Netherlands agree reasonably well with the two observed direct radon flux measurements (within 2σ level). On the European scale, we find that the observed radon flux values are higher than our modelled values and we introduce a correction factor to account for this difference. Our approach discussed in this paper enables us to develop reliable and accurate radon flux maps in countries with little or no information on radon flux values.

  18. Correlated time derivatives of current, electric field intensity, and magnetic flux density for triggered lightning at 15 m

    NASA Astrophysics Data System (ADS)

    Uman, M. A.; Schoene, J.; Rakov, V. A.; Rambo, K. J.; Schnetzer, G. H.

    2002-07-01

    We present measured current and its time derivative correlated with the corresponding electric field intensity and magnetic flux density and their time derivatives measured at 15 m for two lightning return strokes triggered in 1999 at Camp Blanding, Florida. Lightning was triggered to a vertical 2-m rod mounted at the center of a 70 × 70 m buried metallic grid. The rocket-launching system was located underground at the center of the grid. The experiment was designed to minimize any influence of either the strike object or a finite-conducting Earth (ground surface arcing and propagation effects) on the fields and field derivatives. The measured current derivative waveform and the return stroke portion of the magnetic flux density derivative and electric field intensity derivative waveforms associated with the two strokes are observed to be essentially unipolar pulses that have similar waveshapes for the first 150 ns or so, including the initial rising portion, the peak, and about 50 ns after the peak. The current and magnetic field derivative waveshapes are very similar for their total duration, and both decay to near zero about 200 ns after the peak derivative is reached. The electric field derivative decays more slowly than the current derivative after about 150 ns, taking about 500 ns to decay to near zero. The transmission-line model, the simplest available and most used return stroke model, is employed to calculate the return stroke field derivatives, given the measured current derivative as a model input, for return stroke speeds of 1 × 108 m s-1, 2 × 108 m s-1, and 3 × 108 m s-1 (the speed of light). A reasonable match between calculated and measured field derivative waveshapes is achieved for both strokes for a return stroke speed between 2 × 108 m s-1 and 3 × 108 m s-1. Although the measured field and current derivatives have similar waveshapes for about 150 ns, which might appear to be consistent with the hypothesis that the radiation field component

  19. The momentum flux-gradient relations derived from field measurements in the urban roughness sublayer in three cities in China

    NASA Astrophysics Data System (ADS)

    Zou, Jun; Liu, Gang; Sun, Jianning; Zhang, Hongsheng; Yuan, Renmin

    2015-10-01

    Field measurements of the momentum flux and wind velocity gradient were carried out at three urban sites in the cities of Nanjing, Changzhou, and Suzhou, China. The observational data in the urban roughness sublayer are analyzed to derive the momentum flux-gradient relations in terms of framework of the local similarity theory with a least squares fit, and the relations are then compared to the classical similarity relations of Businger et al. (1971). The results show that the momentum flux varies with height; thus, the constant-flux assumption in the Monin-Obukhov Similarity Theory is not met in the urban roughness sublayer. However, the dimensionless wind velocity gradient may be described by the local similarity theory, and the derived flux-gradient relations have the same form as the classical similarity relations do. Under stable conditions, the coefficient βm in the fitted relations increases with height and gradually approaches the value of 4.7 in the classical similarity relations. The trend suggests that the turbulent flow may be described by the classical similarity relations once the height increases and reaches the top of the urban roughness sublayer, and thus, the height of the top of the urban roughness sublayer may be estimated by linear extrapolation of the derived relations in this study. The relation between the critical Richardson number Ric and the coefficient βm is derived as Ric = Prt/βm, where Prt is the turbulent Prandtl number. In the urban roughness sublayer, the value of Ric is larger than 0.2.

  20. Atmospheric freshwater fluxes and their effect on the global thermohaline circulation

    SciTech Connect

    Zaucker, F.; Stocker, T.F.; Broecker, W.S.

    1994-06-15

    Atmospheric water vapor fluxes were derived from a 1-year data set of horizontal wind speed and specific humidity assimilated from meteorological observations by the European Center for Medium-Range Weather Forecast (ECMWF). Vertically integrated horizontal freshwater fluxes were compared to those of two data sets based on a climatology and on simulations with an atmospheric general circulation model (AGCM). Zonal transports agree fairly well at all latitudes outside the tropics, where fluxes are about double for the AGCM data set. Meridional fluxes of the AGCM and ECMWF data sets show close agreement, while the climatological fluxes are generally smaller with a considerable northward shift in the southern hemisphere. Atmosphere-to-ocean freshwater fluxes were derived from the three data sets. Not only is there substantial disagreement between the data sets, but their zonal averages over the Atlantic, Pacific, and Indian Ocean basins show little resemblance to the respective restoring freshwater fluxes from a 2-dimensional ocean model. If the ocean model is forced with the observed and modeled atmospheric fluxes, we find that the mode of ocean circulation is determined mostly the net flux to the high-latitude oceans and the amount of freshwater exported from the Atlantic basin. The latitudinal structure of the freshwater fluxes in low-latitudes and midlatitudes has little influence on the modeled thermohaline circulation. The fluxes derived from the climatology and ECMWF permit North Atlantic Deep Water (NADW) formation, but a strong freshwater input to the Southern Ocean inhibits Antarctic Bottom Water formation. The AGCM transports so much moisture to the Arctic Ocean that NADW formation is shut down, resulting in a ocean circulation mode of southern sinking in all three ocean basins.

  1. How well can regional fluxes be derived from smaller-scale estimates?

    NASA Technical Reports Server (NTRS)

    Moore, Kathleen E.; Fitzjarrald, David R.; Ritter, John A.

    1993-01-01

    Regional surface fluxes are essential lower boundary conditions for large scale numerical weather and climate models and are the elements of global budgets of important trace gases. Surface properties affecting the exchange of heat, moisture, momentum and trace gases vary with length scales from one meter to hundreds of km. A classical difficulty is that fluxes have been measured directly only at points or along lines. The process of scaling up observations limited in space and/or time to represent larger areas was done by assigning properties to surface classes and combining estimated or calculated fluxes using an area weighted average. It is not clear that a simple area weighted average is sufficient to produce the large scale from the small scale, chiefly due to the effect of internal boundary layers, nor is it known how important the uncertainty is to large scale model outcomes. Simultaneous aircraft and tower data obtained in the relatively simple terrain of the western Alaska tundra were used to determine the extent to which surface type variation can be related to fluxes of heat, moisture, and other properties. Surface type was classified as lake or land with aircraft borne infrared thermometer, and flight level heat and moisture fluxes were related to surface type. The magnitude and variety of sampling errors inherent in eddy correlation flux estimation place limits on how well any flux can be known even in simple geometries.

  2. How well can regional fluxes be derived from smaller-scale estimates?

    NASA Technical Reports Server (NTRS)

    Moore, Kathleen E.; Fitzjarrald, David R.; Ritter, John A.

    1992-01-01

    Regional surface fluxes are essential lower boundary conditions for large scale numerical weather and climate models and are the elements of global budgets of important trace gases. Surface properties affecting the exchange of heat, moisture, momentum and trace gases vary with length scales from one meter to hundreds of km. A classical difficulty is that fluxes have been measured directly only at points or along lines. The process of scaling up observations limited in space and/or time to represent larger areas was done by assigning properties to surface classes and combining estimated or calculated fluxes using an area weighted average. It is not clear that a simple area weighted average is sufficient to produce the large scale from the small scale, chiefly due to the effect of internal boundary layers, nor is it known how important the uncertainty is to large scale model outcomes. Simultaneous aircraft and tower data obtained in the relatively simple terrain of the western Alaska tundra were used to determine the extent to which surface type variation can be related to fluxes of heat, moisture, and other properties. Surface type was classified as lake or land with aircraft borne infrared thermometer, and flight level heat and moisture fluxes were related to surface type. The magnitude and variety of sampling errors inherent in eddy correlation flux estimation place limits on how well any flux can be known even in simple geometries.

  3. Atmospheric moisture transport and fresh water flux over oceans derived from spacebased sensors

    NASA Technical Reports Server (NTRS)

    Liu, W. T.; Tang, W.

    2001-01-01

    preliminary results will be shown to demonstrate the application of spacebased IMT and fresh water flux in ocean-atmosphere-land interaction studies, such as the hydrologica balance on Amazon rainfall and Indian monsoon.

  4. SURFACE HEAT FLUX DERIVED FROM SODAR AMPLITUDE AND FREQUENCY DATA: A COMPARISON

    EPA Science Inventory

    Sensible heat flux measurements were made in an agricultural setting near Champaign, Illinois by using doppler sodar, eddy correlations and profile methods during convective conditions during an experimental study called VOICE, (Vertical Observations Involving Convective Exchange...

  5. First space-based derivation of the global atmospheric methanol emission fluxes

    NASA Astrophysics Data System (ADS)

    Stavrakou, T.; Guenther, A.; Razavi, A.; Clarisse, L.; Clerbaux, C.; Coheur, P.-F.; Hurtmans, D.; Karagulian, F.; de Mazière, M.; Vigouroux, C.; Amelynck, C.; Schoon, N.; Laffineur, Q.; Heinesch, B.; Aubinet, M.; Müller, J.-F.

    2011-02-01

    This study provides improved methanol emission estimates on the global scale, in particular for the largest methanol source, the terrestrial biosphere, and for biomass burning. To this purpose, one complete year of spaceborne measurements of tropospheric methanol columns retrieved for the first time by the thermal infrared sensor IASI aboard the MetOp satellite are compared with distributions calculated by the IMAGESv2 global chemistry-transport model. Two model simulations are performed using a priori biogenic methanol emissions either from the new MEGANv2.1 emission model, which is fully described in this work and is based on net ecosystem flux measurements, or from a previous parameterization based on net primary production by Jacob et al. (2005). A significantly better model performance in terms of both amplitude and seasonality is achieved through the use of MEGANv2.1 in most world regions, with respect to IASI data, and to surface- and air-based methanol measurements, even though important discrepancies over several regions are still present. As a second step of this study, we combine the MEGANv2.1 and the IASI column abundances over continents in an inverse modelling scheme based on the adjoint of the IMAGESv2 model to generate an improved global methanol emission source. The global optimized source totals 187 Tg yr-1 with a contribution of 100 Tg yr-1 from plants, only slightly lower than the a priori MEGANv2.1 value of 105 Tg yr-1. Large decreases with respect to the MEGANv2.1 biogenic source are inferred over Amazonia (up to 55%) and Indonesia (up to 58%), whereas more moderate reductions are recorded in the Eastern US (20-25%) and Central Africa (25-35%). On the other side, the biogenic source is found to strongly increase in the arid and semi-arid regions of Central Asia (up to a factor of 5) and Western US (factor of 2), probably due to a source of methanol specific to these ecosystems which is unaccounted for in the MEGANv2.1 inventory. Detailed

  6. An empirical model of electron and ion fluxes derived from observations at geosynchronous orbit

    SciTech Connect

    Denton, M. H.; Thomsen, M. F.; Jordanova, V. K.; Henderson, M. G.; Borovsky, J. E.; Denton, J. S.; Pitchford, D.; Hartley, D. P.

    2015-04-01

    Knowledge of the plasma fluxes at geosynchronous orbit is important to both scientific and operational investigations. We present a new empirical model of the ion flux and the electron flux at geosynchronous orbit (GEO) in the energy range ~1 eV to ~40 keV. The model is based on a total of 82 satellite-years of observations from the Magnetospheric Plasma Analyzer instruments on Los Alamos National Laboratory satellites at GEO. These data are assigned to a fixed grid of 24 local-times and 40 energies, at all possible values of Kp. Bi-linear interpolation is used between grid points to provide the ion flux and the electron flux values at any energy and local-time, and for given values of geomagnetic activity (proxied by the 3-hour Kp index), and also for given values of solar activity (proxied by the daily F10.7 index). Initial comparison of the electron flux from the model with data from a Compact Environmental Anomaly Sensor II (CEASE-II), also located at geosynchronous orbit, indicate a good match during both quiet and disturbed periods. The model is available for distribution as a FORTRAN code that can be modified to suit user-requirements.

  7. An empirical model of electron and ion fluxes derived from observations at geosynchronous orbit

    NASA Astrophysics Data System (ADS)

    Denton, M. H.; Thomsen, M. F.; Jordanova, V. K.; Henderson, M. G.; Borovsky, J. E.; Denton, J. S.; Pitchford, D.; Hartley, D. P.

    2015-04-01

    Knowledge of the plasma fluxes at geosynchronous orbit is important to both scientific and operational investigations. We present a new empirical model of the ion flux and the electron flux at geosynchronous orbit (GEO) in the energy range ~1 eV to ~40 keV. The model is based on a total of 82 satellite years of observations from the magnetospheric plasma analyzer instruments on Los Alamos National Laboratory satellites at GEO. These data are assigned to a fixed grid of 24 local times and 40 energies, at all possible values of Kp. Bilinear interpolation is used between grid points to provide the ion flux and the electron flux values at any energy and local time, and for given values of geomagnetic activity (proxied by the 3 h Kp index), and also for given values of solar activity (proxied by the daily F10.7 index). Initial comparison of the electron flux from the model with data from a Compact Environmental Anomaly Sensor II, also located at geosynchronous orbit, indicates a good match during both quiet and disturbed periods. The model is available for distribution as a FORTRAN code that can be modified to suit user requirements.

  8. An empirical model of electron and ion fluxes derived from observations at geosynchronous orbit

    DOE PAGESBeta

    Denton, M. H.; Thomsen, M. F.; Jordanova, V. K.; Henderson, M. G.; Borovsky, J. E.; Denton, J. S.; Pitchford, D.; Hartley, D. P.

    2015-04-01

    Knowledge of the plasma fluxes at geosynchronous orbit is important to both scientific and operational investigations. We present a new empirical model of the ion flux and the electron flux at geosynchronous orbit (GEO) in the energy range ~1 eV to ~40 keV. The model is based on a total of 82 satellite-years of observations from the Magnetospheric Plasma Analyzer instruments on Los Alamos National Laboratory satellites at GEO. These data are assigned to a fixed grid of 24 local-times and 40 energies, at all possible values of Kp. Bi-linear interpolation is used between grid points to provide the ionmore » flux and the electron flux values at any energy and local-time, and for given values of geomagnetic activity (proxied by the 3-hour Kp index), and also for given values of solar activity (proxied by the daily F10.7 index). Initial comparison of the electron flux from the model with data from a Compact Environmental Anomaly Sensor II (CEASE-II), also located at geosynchronous orbit, indicate a good match during both quiet and disturbed periods. The model is available for distribution as a FORTRAN code that can be modified to suit user-requirements.« less

  9. Can organic matter flux profiles be diagnosed using remineralisation rates derived from observed tracers and modelled ocean transport rates?

    NASA Astrophysics Data System (ADS)

    Wilson, J. D.; Ridgwell, A.; Barker, S.

    2015-03-01

    The average depth in the ocean at which the majority of sinking organic matter particles remineralise is a fundamental parameter in the oceans role in regulating atmospheric CO2. Observed spatial patterns in sinking fluxes and relationships between the fluxes of different particles in the modern ocean have widely been used to invoke controlling mechanisms with important implications for CO2 regulation. However, such analyses are limited by the sparse spatial sampling of the available sediment trap data. Here we explore whether model ocean circulation rates, in the form of a transport matrix, can be used to derive remineralisation rates and sinking particle flux curves from the much more highly resolved observations of dissolved nutrient concentrations. Initially we use the Earth system model GENIE to generate a synthetic tracer dataset to explore the methods and its sensitivity to key sources of uncertainty arising from errors in the tracer observations and in the model circulation. We use a perturbed physics ensemble to generate 54 different estimates of circulation to explore errors associated with model transport rates. We find that reconstructed remineralisation rates are highly sensitive to both errors in observations and our ensemble uncertainty in model circulation rates such that a simple inversion does not provide a robust estimate of particulate flux profiles. Inferred remineralisation rates are particularly sensitive to differences between the "observed" and modelled transport fluxes because remineralisation rates are 3-4 magnitudes smaller than circulation rates. We also find that when inferring particle flux curves from remineralisation rates the cycling of dissolved organic matter also creates biases that have a similar magnitude and spatial variability to flux curves diagnosed using sediment trap data. We end with a discussion on the potential future directions and pitfalls of estimating remineralisation rates using model circulation schemes.

  10. Multiyear sea ice thermal regimes and oceanic heat flux derived from an ice mass balance buoy in the Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Lei, Ruibo; Li, Na; Heil, Petra; Cheng, Bin; Zhang, Zhanhai; Sun, Bo

    2014-01-01

    The conductive and oceanic heat fluxes and the mass balance of sea ice were investigated utilizing an ice mass balance buoy (IMB) deployed in the Arctic Ocean. After IMB deployment, the ice thinned from 1.95 m in late August to 1.46 m by mid-October 2008. From then on, ice growth until mid-June 2009 increased the ice thickness to 3.12 m. The ice temperature and consequently the conductive heat flux at the ice surface exhibited persistent high-frequency variations due to diurnal and synoptic-scale atmospheric forcing. These signals propagated downward with damped magnitude and temporal lag. The competition of oceanic and conductive heat flux dominated the low-frequency variations of ice growth. However, high-frequency variations in ice growth were controlled largely by the oceanic heat flux. From mid-November 2008 to mid-June 2009, the average oceanic heat flux along a track from 86.2°N, 115.2°W to 84.6°N, 33.9°W was 7.1 W/m2. This was in agreement with that derived from an IMB deployed in 2005, about 1.5° to the north of our buoy. We attributed the relatively high oceanic heat flux (10-15 W/m2) observed during autumn and early winter to summer warming of the surface ocean. Upward mixing of warm deep water, as observed when our buoy drifted over the shallow region of the Lomonosov Ridge (85.4°-85.9°N, 52.2°-66.4°W), demonstrated the impact of bathymetry on the oceanic heat flux under ice cover, and consequently on the basal ice mass balance.

  11. EUMELI oligotrophic site: response of an upper ocean model to climatological and ECMWF atmospheric forcing

    NASA Astrophysics Data System (ADS)

    Dadou, Isabelle C.; Garçon, Véronique C.

    1993-11-01

    Within the frame of the EUMELI program—component of FRANCE-JGOFS—in the Northeast tropical Atlantic ocean, we investigate the potential of a one-dimensional eddy-kinetic-energy model (Gaspar et al., 1990, GGL) to characterize the vertical dynamics of the oceanic mixed layer (ML) at the EUMELI oligotrophic site (21°N, 31°W) north of the Cape Verde Frontal Zone. The atmospheric forcings used are derived from two different sources: the operational Atmospheric General Circulation Model of ECMWF (over two 12-month periods: August 1985-July 1986 and the full year 1990) and climatologies (Esbensen and Kushnir, EK, 1981; Hsiung, H, 1986; Oort, 1983). At the site, depending on the data base, the annual mean of the total energy flux at the ocean-atmosphere interface differs in sign and intensity and its monthly evolution presents significant variation both in amplitude and timing of the maximum. The monthly wind stress evolution due to the regular north-east trade winds prevailing in this region is quite consistent as derived by the different data sources. In our area, a net evaporation rate occurs throughout the year. The simulated ML depth, based on GGL's ML depth definition, is always shallower than climatological observations of ML depth, whatever the surface atmospherical forcing used, the exception being the simulation performed with the atypical ECMWF85-86 forcing. The simulated SST's using H forcing compare rather well (within 1°C) with the observed SST's of the climatologies of Lamb and EK. Sampling experiments on the surface boundary conditions showed that simulated evolutions of the ML depth and SST differ quite significantly due to differences in data bases rather than differences in forcing frequencies. An error analysis on the ocean surface energy fluxes and the prescription of evaporation and precipitation rates under various forms demonstrate the crucial need for heat, momentum and freshwater fluxes estimates as accurate as possible. From the

  12. Relationship between Metabolic Fluxes and Sequence-Derived Properties of Enzymes

    PubMed Central

    Kampenusa, Inara

    2014-01-01

    Metabolic fluxes are key parameters of metabolic pathways being closely related to the kinetic properties of enzymes, thereby could be dependent on. This study examines possible relationships between the metabolic fluxes and the physical-chemical/structural features of enzymes from the yeast Saccharomyces cerevisiae glycolysis pathway. Metabolic fluxes were quantified by the COPASI tool using the kinetic models of Hynne and Teusink at varied concentrations of external glucose. The enzyme sequences were taken from the UniProtKB and the average amino acid (AA) properties were computed using the set of Georgiev's uncorrelated scales that satisfy the VARIMAX criterion and specific AA indices that show the highest correlations with those. Multiple linear regressions (88.41% fluxes and the selected sets of the average AA properties. The hydrophobicity, α-helicity, and net charge were pointed out as the most influential characteristics of the sequences. The results provide an evidence that metabolic fluxes of the yeast glycolysis pathway are closely related to certain physical-chemical properties of relevant enzymes and support the view on the interdependence of catalytic, binding, and structural AA residues to ensure the efficiency of biocatalysts and, hence, physiologically adequate metabolic processes.

  13. Regional CO2 fluxes for eastern Amazonia derived from aircraft vertical profiles

    NASA Astrophysics Data System (ADS)

    Gatti, L. V.; Miller, J. B.; D'Amelio, M. T.; Wofsy, S.; Tans, P.

    2008-12-01

    We have determined regional scale (~105 - 106 km2) CO2 fluxes using atmospheric measurements from aircraft vertical profiles over eastern Amazonia (site SAN: 02°51'S; 54°57'W). Profiles started December 2000 and have continued through 2008. 17 air samples per profile were collected aboard light aircraft between the surface and 4-5 km using the NOAA/ESRL semi- automatic portable flask package. We use a column integration technique to determine the CO2 flux for each vertical profile, where the measured CO2 profile is differenced from a CO2 background, which was determined using co-measured SF6 as a transport tracer. Two NOAA/ESRL background sites, Ascension Island (ASC) located in the Atlantic Ocean (8°S, 14°W) and Barbados (RPB) located in the Atlantic Ocean (12°N, 59°W) were used to calculate the fractions of air arriving at the sites studied. Back trajectories from the HYSPLIT model were calculated for every profile every 500m of altitude to determine the time the air mass took to travel between the coast and SAN. The observed flux, which is representative of that between the coast and measurement sites, averaged -0.03 ± 1.5 g C m-2day-1 for the wet season and 0.3 ± 0.9 g C m-2day-1 for the dry season. The flux variability is high, probably reflecting the dynamic nature of the response of the terrestrial biosphere to environmental conditions. We have attempted to remove the influence of biomass burning from the fluxes using measurements of co-measured CO. This reduces the dry season flux to -0.04 ± 1.2 g C m- 2day-1. We will compare these results to the seasonality found in eddy covariance measurements and to that estimated from models of the terrestrial biosphere.

  14. Estimating Carbon Flux Phenology with Satellite-Derived Land Surface Phenology and Climate Drivers for Different Biomes: A Synthesis of AmeriFlux Observations

    PubMed Central

    Zhu, Wenquan; Chen, Guangsheng; Jiang, Nan; Liu, Jianhong; Mou, Minjie

    2013-01-01

    Carbon Flux Phenology (CFP) can affect the interannual variation in Net Ecosystem Exchange (NEE) of carbon between terrestrial ecosystems and the atmosphere. In this study, we proposed a methodology to estimate CFP metrics with satellite-derived Land Surface Phenology (LSP) metrics and climate drivers for 4 biomes (i.e., deciduous broadleaf forest, evergreen needleleaf forest, grasslands and croplands), using 159 site-years of NEE and climate data from 32 AmeriFlux sites and MODIS vegetation index time-series data. LSP metrics combined with optimal climate drivers can explain the variability in Start of Carbon Uptake (SCU) by more than 70% and End of Carbon Uptake (ECU) by more than 60%. The Root Mean Square Error (RMSE) of the estimations was within 8.5 days for both SCU and ECU. The estimation performance for this methodology was primarily dependent on the optimal combination of the LSP retrieval methods, the explanatory climate drivers, the biome types, and the specific CFP metric. This methodology has a potential for allowing extrapolation of CFP metrics for biomes with a distinct and detectable seasonal cycle over large areas, based on synoptic multi-temporal optical satellite data and climate data. PMID:24386441

  15. A Total Lightning Climatology for the Tennessee Valley Region

    NASA Technical Reports Server (NTRS)

    McCaul, E. W.; Goodman, S. J.; Buechler, D. E.; Blakeslee, R.; Christian, H.; Boccippio, D.; Koshak, W.; Bailey, J.; Hallm, J.; Bateman, M.

    2003-01-01

    Total flash counts derived from the North Alabama Lightning Mapping Array are being processed for 2002 to form a climatology of total lightning for the Tennessee Valley region. The data from this active and interesting period will be compared to data fiom the National Lightning Detection Network, space-based lightning sensors, and weather radars.

  16. Deriving hourly surface energy fluxes and ET from Landsat Thematic mapper data using METRIC

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surface energy fluxes and evapotranspiration (ET) have long been recognized as playing an important role in determining exchanges of energy and mass between the hydrosphere, atmosphere, and biosphere. In this study, we applied the METRIC (Mapping ET at high Resolutions with Internal Calibration) alg...

  17. Daily evapotranspiration estimates by scaling instantaneous latent heat flux derived from a two-source model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Radiometric brightness temperature can be used in energy balance models that estimate sensible and latent heat fluxes of the land surface. However, brightness temperature is usually available only at one time of day when acquired from aircraft, fine-scale satellite platforms, or infrared thermometer...

  18. Geogenic Sources Strongly Contribute to the Mackenzie River Delta's Methane Emissions Derived From Airborne Flux Data

    NASA Astrophysics Data System (ADS)

    Kohnert, K.; Serafimovich, A.; Metzger, S.; Hartmann, J.; Sachs, T.

    2015-12-01

    Arctic permafrost-associated wetlands and thawing permafrost emit the greenhouse gas methane (CH4), either as a product of recent microbial activity in the active layer or taliks, or from deeper geogenic sources where pathways through the permafrost exist. Current emission estimates vary strongly between different models and there is still disagreement between bottom-up estimates from local field studies and top-down estimates from atmospheric measurements. We use airborne flux data from two campaigns in the Mackenzie River Delta, Canada, in July 2012 and 2013 to directly quantify permafrost CH4 emissions on the regional scale, to analyse the regional pattern of CH4 fluxes and to estimate the contribution of geogenic emissions to the overall CH4 budget of the delta. CH4 fluxes were calculated with a time-frequency resolved version of the eddy covariance technique, resulting in a gridded 100 m x 100 m resolution flux map within the footprints of the flight tracks. We distinguish geogenic gas seeps from biogenic sources by their strength and show that they contribute strongly to the annual CH4 budget of the delta. Our study provides the first estimate of annual CH4 release from the Mackenzie River Delta and the adjacent coastal plain. We show that one percent of the covered area contains the strongest geogenic seeps which contribute disproportionately to the annual emission estimate. Our results show that geogenic CH4 emissions might need more attention, especially in areas where permafrost is vulnerable to thawing sufficiently to create pathways for geogenic gas migration. The presented map can be used as a baseline for future CH4 flux studies in the Mackenzie River Delta.

  19. Developing a cloud mask climatology covering two Meteosat satellite generations

    NASA Astrophysics Data System (ADS)

    Posselt, Rebekka; Stöckli, Reto; Liniger, Mark A.

    2013-04-01

    Long term cloud cover observations from satellites are fundamental for climate model validation and climate monitoring. Further, they support ground-based observations in regions with sparse coverage. Additionally, information on cloud cover is needed to derive other physical parameters such as surface radiation fluxes or clear sky and cloudy atmospheric states and is of high relevance for the solar energy sector. Within the current project phase of the Satellite Application Facility on Climate Monitoring (CM SAF) an algorithm to calculate a climatological cloud mask (or cloud cover probability) from Meteosat satellites is developed. The algorithm shall be applicable for both Meteosat first generation (1983-2005) and Meteosat second generation (2004-present) which significantly differ in their spectral properties. The algorithm linearly aggregates a set of continuous scores instead of the commonly used decision tree approach. The scores are calculated for different channels as well as different spatial and temporal settings. Each score yields a probability for the pixel's cloud cover. The final result, the cloud cover probability, is obtained by combining all available scores taking into account the varying performance of the scores during day and night and over snow. The uncertainty of the final cloud cover estimate is an inherent part of the probability. The algorithm is calibrated using cloud cover measurements from SYNOP stations located on the Meteosat disc. The subsequent validation is done at an independent set of collocated SYNOP/ARSA (Automated Radiosonde Archive) stations. The presentation introduces the applied cloud mask algorithm and presents the results of the validation for both satellite generations. The comparison of the two satellite generations addresses the climatological homogeneity of the future cloud mask climate data record which will be distributed by CM SAF after 2016. Special attention is also drawn to issues like the day-night-bias of

  20. Eight Year Climatologies from Observational (AIRS) and Model (MERRA) Data

    NASA Technical Reports Server (NTRS)

    Hearty, Thomas; Savtchenko, Andrey; Won, Young-In; Theobalk, Mike; Vollmer, Bruce; Manning, Evan; Smith, Peter; Ostrenga, Dana; Leptoukh, Greg

    2010-01-01

    We examine climatologies derived from eight years of temperature, water vapor, cloud, and trace gas observations made by the Atmospheric Infrared Sounder (AIRS) instrument flying on the Aqua satellite and compare them to similar climatologies constructed with data from a global assimilation model, the Modern Era Retrospective-Analysis for Research and Applications (MERRA). We use the AIRS climatologies to examine anomalies and trends in the AIRS data record. Since sampling can be an issue for infrared satellites in low earth orbit, we also use the MERRA data to examine the AIRS sampling biases. By sampling the MERRA data at the AIRS space-time locations both with and without the AIRS quality control we estimate the sampling bias of the AIRS climatology and the atmospheric conditions where AIRS has a lower sampling rate. While the AIRS temperature and water vapor sampling biases are small at low latitudes, they can be more than a few degrees in temperature or 10 percent in water vapor at higher latitudes. The largest sampling biases are over desert. The AIRS and MERRA data are available from the Goddard Earth Sciences Data and Information Services Center (GES DISC). The AIRS climatologies we used are available for analysis with the GIOVANNI data exploration tool. (see, http://disc.gsfc.nasa.gov).

  1. Evaluation and Applications of Cloud Climatologies from CALIOP

    NASA Technical Reports Server (NTRS)

    Winker, David; Getzewitch, Brian; Vaughan, Mark

    2008-01-01

    Clouds have a major impact on the Earth radiation budget and differences in the representation of clouds in global climate models are responsible for much of the spread in predicted climate sensitivity. Existing cloud climatologies, against which these models can be tested, have many limitations. The CALIOP lidar, carried on the CALIPSO satellite, has now acquired over two years of nearly continuous cloud and aerosol observations. This dataset provides an improved basis for the characterization of 3-D global cloudiness. Global average cloud cover measured by CALIOP is about 75%, significantly higher than for existing cloud climatologies due to the sensitivity of CALIOP to optically thin cloud. Day/night biases in cloud detection appear to be small. This presentation will discuss detection sensitivity and other issues associated with producing a cloud climatology, characteristics of cloud cover statistics derived from CALIOP data, and applications of those statistics.

  2. Sea ice - atmosphere interaction: Application of multispectral satellite data in polar surface energy flux estimates

    NASA Technical Reports Server (NTRS)

    Steffen, Konrad; Schweiger, A.; Maslanik, J.; Key, J.; Haefliger, M.; Weaver, R.

    1991-01-01

    In the past six months, work has continued on energy flux sensitivity studies, ice surface temperature retrievals, corrections to Advanced Very High Resolution Radiometer (AVHRR) thermal infrared data, modelling of cloud fraction retrievals, and radiation climatologies. We tentatively conclude that the SSM/I may not provide accurate enough estimates of ice concentration and type to improve our shorter term energy flux estimates. SSM/I derived parameters may still be applicable in longer term climatological flux characterizations. We hold promise for a system coupling observation to a ice deformation model. Such a model may provide information on ice distribution which can be used in energy flux calculations. Considerable variation was found in modelled energy flux estimates when bulk transfer coefficients are modulated by lead fetch. It is still unclear what the optimum formulation is and this will be the subject of further work. Data sets for ice surface temperature retrievals were assembled and preliminary data analysis was started. Finally, construction of a conceptual framework for further modelling of the Arctic radiation flux climatology was started.

  3. Active Learning in Introductory Climatology.

    ERIC Educational Resources Information Center

    Dewey, Kenneth F.; Meyer, Steven J.

    2000-01-01

    Introduces a software package available for the climatology curriculum that determines possible climatic events according to a long-term climate history. Describes the integration of the software into the curriculum and presents examples of active learning. (Contains 19 references.) (YDS)

  4. Climatological Downscaling and Evaluation of AGRMET Precipitation Analyses Over the Continental U.S.

    NASA Astrophysics Data System (ADS)

    Garcia, M.; Peters-Lidard, C. D.; Eylander, J. B.; Daly, C.; Tian, Y.; Zeng, J.

    2007-05-01

    The spatially distributed application of a land surface model (LSM) over a region of interest requires the application of similarly distributed precipitation fields that can be derived from various sources, including surface gauge networks, surface-based radar, and orbital platforms. The spatial variability of precipitation influences the spatial organization of soil temperature and moisture states and, consequently, the spatial variability of land- atmosphere fluxes. The accuracy of spatially-distributed precipitation fields can contribute significantly to the uncertainty of model-based hydrological states and fluxes at the land surface. Collaborations between the Air Force Weather Agency (AFWA), NASA, and Oregon State University have led to improvements in the processing of meteorological forcing inputs for the NASA-GSFC Land Information System (LIS; Kumar et al. 2006), a sophisticated framework for LSM operation and model coupling experiments. Efforts at AFWA toward the production of surface hydrometeorological products are currently in transition from the legacy Agricultural Meteorology modeling system (AGRMET) to use of the LIS framework and procedures. Recent enhancements to meteorological input processing for application to land surface models in LIS include the assimilation of climate-based information for the spatial interpolation and downscaling of precipitation fields. Climatological information included in the LIS-based downscaling procedure for North America is provided by a monthly high-resolution PRISM (Daly et al. 1994, 2002; Daly 2006) dataset based on a 30-year analysis period. The combination of these sources and methods attempts to address the strengths and weaknesses of available legacy products, objective interpolation methods, and the PRISM knowledge-based methodology. All of these efforts are oriented on an operational need for timely estimation of spatial precipitation fields at adequate spatial resolution for customer dissemination and

  5. Deriving a light use efficiency model from eddy covariance flux data for predicting daily gross primary production across biomes

    USGS Publications Warehouse

    Yuan, W.; Liu, S.; Zhou, G.; Tieszen, L.L.; Baldocchi, D.; Bernhofer, C.; Gholz, H.; Goldstein, Allen H.; Goulden, M.L.; Hollinger, D.Y.; Hu, Y.; Law, B.E.; Stoy, P.C.; Vesala, T.; Wofsy, S.C.

    2007-01-01

    The quantitative simulation of gross primary production (GPP) at various spatial and temporal scales has been a major challenge in quantifying the global carbon cycle. We developed a light use efficiency (LUE) daily GPP model from eddy covariance (EC) measurements. The model, called EC-LUE, is driven by only four variables: normalized difference vegetation index (NDVI), photosynthetically active radiation (PAR), air temperature, and the Bowen ratio of sensible to latent heat flux (used to calculate moisture stress). The EC-LUE model relies on two assumptions: First, that the fraction of absorbed PAR (fPAR) is a linear function of NDVI; Second, that the realized light use efficiency, calculated from a biome-independent invariant potential LUE, is controlled by air temperature or soil moisture, whichever is most limiting. The EC-LUE model was calibrated and validated using 24,349 daily GPP estimates derived from 28 eddy covariance flux towers from the AmeriFlux and EuroFlux networks, covering a variety of forests, grasslands and savannas. The model explained 85% and 77% of the observed variations of daily GPP for all the calibration and validation sites, respectively. A comparison with GPP calculated from the Moderate Resolution Imaging Spectroradiometer (MODIS) indicated that the EC-LUE model predicted GPP that better matched tower data across these sites. The realized LUE was predominantly controlled by moisture conditions throughout the growing season, and controlled by temperature only at the beginning and end of the growing season. The EC-LUE model is an alternative approach that makes it possible to map daily GPP over large areas because (1) the potential LUE is invariant across various land cover types and (2) all driving forces of the model can be derived from remote sensing data or existing climate observation networks. ?? 2007 Elsevier B.V. All rights reserved.

  6. Can organic matter flux profiles be diagnosed using remineralisation rates derived from observed tracers and modelled ocean transport rates?

    NASA Astrophysics Data System (ADS)

    Wilson, J. D.; Ridgwell, A.; Barker, S.

    2015-09-01

    The average depth in the ocean at which the majority of sinking organic matter particles remineralise is a fundamental parameter in the ocean's role in regulating atmospheric CO2. Observed spatial patterns in sinking fluxes and relationships between the fluxes of different particles in the modern ocean have widely been used to invoke controlling mechanisms with important implications for CO2 regulation. However, such analyses are limited by the sparse spatial sampling of the available sediment trap data. Here we explore whether model ocean circulation rates, in the form of a transport matrix, can be used to derive remineralisation rates and infer sinking particle flux curves from the much more highly resolved observations of dissolved nutrient concentrations. Initially we show an example of the method using a transport matrix from the MITgcm model and demonstrate that there are a number of potential uncertainties associated with the method. We then use the Earth system model GENIE to generate a synthetic tracer data set to explore the method and its sensitivity to key sources of uncertainty arising from errors in the tracer observations and in the model circulation. We use a 54-member ensemble of different, but plausible, estimates of the modern circulation to explore errors associated with model transport rates. We find that reconstructed re-mineralisation rates are very sensitive to both errors in observations and model circulation rates, such that a simple inversion cannot provide a robust estimate of particulate flux profiles. Estimated remineralisation rates are particularly sensitive to differences between the "observed" and modelled circulation because remineralisation rates are 3-4 magnitudes smaller than transport rates. We highlight a potential method of constraining the uncertainty associated with using modelled circulation rates, although its success is limited by the observations currently available. Finally, we show that there are additional

  7. The effect of assimilating satellite derived soil moisture in SiBCASA on simulated carbon fluxes in Boreal Eurasia

    NASA Astrophysics Data System (ADS)

    van der Molen, M. K.; de Jeu, R. A. M.; Wagner, W.; van der Velde, I. R.; Kolari, P.; Kurbatova, J.; Varlagin, A.; Maximov, T. C.; Kononov, A. V.; Ohta, T.; Kotani, A.; Krol, M. C.; Peters, W.

    2015-09-01

    Boreal Eurasia is a region where the interaction between droughts and the carbon cycle may have significant impacts on the global carbon cycle. Yet the region is extremely data sparse with respect to meteorology, soil moisture and carbon fluxes as compared to e.g. Europe. To better constrain our vegetation model SiBCASA, we increase data usage by assimilating two streams of satellite derived soil moisture. We study if the assimilation improved SiBCASA's soil moisture and its effect on the simulated carbon fluxes. By comparing to unique in situ soil moisture observations, we show that the passive microwave soil moisture product did not improve the soil moisture simulated by SiBCASA, but the active data seem promising in some aspects. The match between SiBCASA and ASCAT soil moisture is best in the summer months over low vegetation. Nevertheless, ASCAT failed to detect the major droughts occurring between 2007 and 2013. The performance of ASCAT soil moisture seems to be particularly sensitive to ponding, rather than to biomass. The effect on the simulated carbon fluxes is large, 5-10% on annual GPP and TER, and tens of percent on local NEE, and 2% on area-integrated NEE, which is the same order of magnitude as the inter-annual variations. Consequently, this study shows that assimilation of satellite derived soil moisture has potentially large impacts, while at the same time further research is needed to understand under which conditions the satellite derived soil moisture improves the simulated soil moisture.

  8. Development of an operational global ocean climatology through the use of remotely sensed sea surface temperature

    SciTech Connect

    Winter, T.M.

    1995-05-09

    Monthly mean satellite-derived sea surface temperature SST data have been derived globally using daytime and nighttime AVHRR (Advanced Very High Resolution Radiometer) multi-channel data. From a 12 year data set (1982-1993), valid monthly daytime and nighttime climatologies were created using an eight year subset (1984-1990, 1993). Based on buoy comparisons, four years were omitted due to volcanic aerosol corruption (El Chichon 1982/83, Mt. Pinatubo 1991/92). These resulting monthly climatologies provide SST fields at approximately 1/3rd degree latitude/longitude resolution. Difference fields have been created comparing the new satellite climatology with the older and coarser-resolution climatology constructed from conventional SST data. Regional and zonal climatology differences were also created to highlight the deficiencies, especially in the Southern Hemisphere, in the older climatology believed to result primarily from a lack of buoy/ship (in situ) data. Such comparisons made it clear that the satellite climatology provided a much better product. Ocean current systems, El Nino, La Nina, and other water mass characteristics all appear with better detail and accuracy within the high-resolution satellite climatology.

  9. Validating hydro-meteorological fluxes using GRACE-derived water storage changes - a global and regional perspective

    NASA Astrophysics Data System (ADS)

    Eicker, Annette; Springer, Anne; Kusche, Jürgen; Jütten, Thomas; Diekkrüger, Bernd; Longuevergne, Laurent

    2016-04-01

    Atmospheric and terrestrial water budgets, which represent important boundary conditions for both climate modeling and hydrological studies, are linked by evapotranspiration (E) and precipitation (P). These fields are provided by numerical weather prediction models and atmospheric reanalyses such as ERA-Interim and MERRA-Land; yet, in particular the quality of E is still not well evaluated. Via the terrestrial water budget equation, water storage changes derived from products of the Gravity Recovery and Climate Experiment (GRACE) mission, combined with runoff (R) data can be used to assess the realism of atmospheric models. While on short temporal scales (inter-annual down to sub-seasonal) the modeled fluxes agree remarkably well with GRACE water storage changes, the models exhibit large biases and fail to capture the long-term flux trends in P-E-R corresponding to GRACE accelerations (Eicker et al. 2016). This leads to the assumption that despite the short time span of available gravity field observations, GRACE is able to provide new information for constraining the long-term evolution of water fluxes in future atmospheric reanalyses. In this contribution we will investigate the agreement of GRACE water storage changes with P-E-R flux time series from different (global and regional) atmospheric reanalyses, land surface models, as well as observation-based data sets. We will perform a global analyses and we will additionally focus on selected river basins. The investigations will be carried out for various temporal scales, focussing on the short-term fluxes (month-to-month variations), for which models and GRACE agree well with correlations of the de-trended and de-seasoned fluxes time series reaching up to 0.8 and more. We will furthermore extent the study towards even higher temporal frequencies, investigating whether the modeled and observed fluxes show sub-monthly variability that can be detected in daily GRACE time series. Eicker, A., E. Forootan, A. Springer

  10. A climatology of visible surface reflectance spectra

    NASA Astrophysics Data System (ADS)

    Zoogman, Peter; Liu, Xiong; Chance, Kelly; Sun, Qingsong; Schaaf, Crystal; Mahr, Tobias; Wagner, Thomas

    2016-09-01

    We present a high spectral resolution climatology of visible surface reflectance as a function of wavelength for use in satellite measurements of ozone and other atmospheric species. The Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument is planned to measure backscattered solar radiation in the 290-740 nm range, including the ultraviolet and visible Chappuis ozone bands. Observation in the weak Chappuis band takes advantage of the relative transparency of the atmosphere in the visible to achieve sensitivity to near-surface ozone. However, due to the weakness of the ozone absorption features this measurement is more sensitive to errors in visible surface reflectance, which is highly variable. We utilize reflectance measurements of individual plant, man-made, and other surface types to calculate the primary modes of variability of visible surface reflectance at a high spectral resolution, comparable to that of TEMPO (0.6 nm). Using the Moderate-resolution Imaging Spectroradiometer (MODIS) Bidirection Reflectance Distribution Function (BRDF)/albedo product and our derived primary modes we construct a high spatial resolution climatology of wavelength-dependent surface reflectance over all viewing scenes and geometries. The Global Ozone Monitoring Experiment-2 (GOME-2) Lambertian Equivalent Reflectance (LER) product provides complementary information over water and snow scenes. Preliminary results using this approach in multispectral ultraviolet+visible ozone retrievals from the GOME-2 instrument show significant improvement to the fitting residuals over vegetated scenes.

  11. Particulate organic carbon export fluxes on Chukchi Shelf, western Arctic Ocean, derived from 210Po/210Pb disequilibrium

    NASA Astrophysics Data System (ADS)

    He, Jianhua; Yu, Wen; Lin, Wuhui; Men, Wu; Chen, Liqi

    2015-05-01

    Fluxes of particulate organic carbon (POC) were derived from 210Po/210Pb disequilibrium during the 4th Chinese National Arctic Research Expedition (CHINARE-4) from July 1 to September 28, 2010. Average residence times of particulate 210Po in the euphotic zone were -16.00 a to 1.54 a, which are higher than those of dissolved 210Po (-6.89 a to -0.70 a). Great excesses of dissolved 210Po were observed at all stations, with an average 210Po/210Pb ratio of 1.91±0.20, resulting from 210Pb atmospheric deposition after sea ice melt. POC fluxes from the euphotic zone were estimated by two methods (E and B) in the irreversible scavenging model. Estimated POC fluxes were 945-126 mmol C/(m2·a) and 1 848-109 mmol C/(m2·a) by methods E and B, respectively, both decreasing from low to high latitude. The results are comparable to previous works for the same region, indicating efficient biological pumping in the Chukchi Sea. The results can improve understanding of the carbon cycle in the western Arctic Ocean.

  12. A genome-scale metabolic flux model of Escherichia coli K–12 derived from the EcoCyc database

    PubMed Central

    2014-01-01

    Background Constraint-based models of Escherichia coli metabolic flux have played a key role in computational studies of cellular metabolism at the genome scale. We sought to develop a next-generation constraint-based E. coli model that achieved improved phenotypic prediction accuracy while being frequently updated and easy to use. We also sought to compare model predictions with experimental data to highlight open questions in E. coli biology. Results We present EcoCyc–18.0–GEM, a genome-scale model of the E. coli K–12 MG1655 metabolic network. The model is automatically generated from the current state of EcoCyc using the MetaFlux software, enabling the release of multiple model updates per year. EcoCyc–18.0–GEM encompasses 1445 genes, 2286 unique metabolic reactions, and 1453 unique metabolites. We demonstrate a three-part validation of the model that breaks new ground in breadth and accuracy: (i) Comparison of simulated growth in aerobic and anaerobic glucose culture with experimental results from chemostat culture and simulation results from the E. coli modeling literature. (ii) Essentiality prediction for the 1445 genes represented in the model, in which EcoCyc–18.0–GEM achieves an improved accuracy of 95.2% in predicting the growth phenotype of experimental gene knockouts. (iii) Nutrient utilization predictions under 431 different media conditions, for which the model achieves an overall accuracy of 80.7%. The model’s derivation from EcoCyc enables query and visualization via the EcoCyc website, facilitating model reuse and validation by inspection. We present an extensive investigation of disagreements between EcoCyc–18.0–GEM predictions and experimental data to highlight areas of interest to E. coli modelers and experimentalists, including 70 incorrect predictions of gene essentiality on glucose, 80 incorrect predictions of gene essentiality on glycerol, and 83 incorrect predictions of nutrient utilization. Conclusion Significant

  13. Latitudinal dependence of solar proton flux derived from interplanetary Lyman alpha emission

    NASA Astrophysics Data System (ADS)

    Nakagawa, H.; Fukunishi, H.; Watanabe, S.; Takahashi, Y.; Taguchi, M.; Bertaux, J.; Quemerais, E.; Lallement, R.

    2004-12-01

    There is a uniform flow of the interplanetary hydrogen in the solar system. The distribution of interplanetary neutral hydrogen is sensitive to solar wind proton flux, which has a latitudinal distribution, because interplanetary neutral hydrogen atoms are mainly ionized through a process of charge-exchange with solar wind protons (contributing to 80% of the total ionization rate). Rucinski et al. [1996] estimated the ionization rate of the interplanetary hydrogen in an average solar activity condition: 6.4±0.14 [10E-7/s] for charge exchange with protons. The most practical technique for determining the latitudinal dependence of the interplanetary hydrogen is observation of resonant backscatter of solar Lyman ƒ¿ emission at 121.6 nm. The interplanetary Lyman ƒ¿ emission has been measured by the ultraviolet imaging spectrometer (UVS) on board the Nozomi spacecraft crusing on its Mars transfer orbit with a periapsis of 1 AU and an apoapsis 1.5 AU from the Sun. The field-of-view of UVS is perpendicular to the spin axis of the spacecraft, which is controlled toward the Earth. The spatial resolution of UVS is 1.41 degrees in a plane perpendicular to the spin axis and 0.29 degrees in a plane including the spin axis. Spatial distributions are obtained from the full sky scanning of UVS with spin and orbital motions of the Nozomi spacecraft. One-year UVS data enable us to construct a full sky image of Lyman ƒ¿ emission. We present the results obtained from Nozomi/UVS data analysis for the period of 1999-2002. From a fitting of model calculations to the observed data, it is confirmed that a latitudinal anisotropy with the higher ionization region at the equator is reduced toward solar maximum. Finally, higher ionization region are found at the poles than at the equator near solar maximum. Basically, this change is produced by variations in the latitudinal dependence of persistent solar wind proton flux. However, proton flux from transient CMEs also affects the

  14. Evaluation of SEBS for Deriving Land Surface Energy Fluxes with MODIS data in a Semiarid Region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Texas High Plains is one of the largest agricultural regions in the United States where 90% of the water derived from the Ogallala Aquifer is used for irrigation. Accurate seasonal evapotranspiration (ET) estimates at a regional scale would be useful for groundwater management purposes. Remote sensi...

  15. Assessing Inter-Sensor Variability and Sensible Heat Flux Derivation Accuracy for a Large Aperture Scintillometer

    PubMed Central

    Rambikur, Evan H.; Chávez, José L.

    2014-01-01

    The accuracy in determining sensible heat flux (H) of three Kipp and Zonen large aperture scintillometers (LAS) was evaluated with reference to an eddy covariance (EC) system over relatively flat and uniform grassland near Timpas (CO, USA). Other tests have revealed inherent variability between Kipp and Zonen LAS units and bias to overestimate H. Average H fluxes were compared between LAS units and between LAS and EC. Despite good correlation, inter-LAS biases in H were found between 6% and 13% in terms of the linear regression slope. Physical misalignment was observed to result in increased scatter and bias between H solutions of a well-aligned and poorly-aligned LAS unit. Comparison of LAS and EC H showed little bias for one LAS unit, while the other two units overestimated EC H by more than 10%. A detector alignment issue may have caused the inter-LAS variability, supported by the observation in this study of differing power requirements between LAS units. It is possible that the LAS physical misalignment may have caused edge-of-beam signal noise as well as vulnerability to signal noise from wind-induced vibrations, both having an impact on the solution of H. In addition, there were some uncertainties in the solutions of H from the LAS and EC instruments, including lack of energy balance closure with the EC unit. However, the results obtained do not show clear evidence of inherent bias for the Kipp and Zonen LAS to overestimate H as found in other studies. PMID:24473285

  16. Quantum Derivative Fitting and Biomolecular Force Fields: Functional Form, Coupling Terms, Charge Flux, Nonbond Anharmonicity, and Individual Dihedral Potentials.

    PubMed

    Hagler, A T

    2015-12-01

    Computer simulations are increasingly prevalent, complementing experimental studies in all fields of biophysics, chemistry, and materials. Their utility, however, is critically dependent on the validity of the underlying force fields employed. In this Perspective we review the ability of quantum mechanics, and in particular analytical ab initio derivatives, to inform on the nature of intra- and intermolecular interactions. The power inherent in the exploitation of forces and second derivatives (Hessians) to derive force fields for a variety of compound types, including inorganic, organic, and biomolecules, is explored. We discuss the use of these quantities along with QM energies and geometries to determine force constants, including nonbond and electrostatic parameters, and to assess the functional form of the energy surface. The latter includes the optimal form of out-of-plane interactions and the necessity for anharmonicity, and terms to account for coupling between internals, to adequately represent the energy of intramolecular deformations. In addition, individual second derivatives of the energy with respect to selected interaction coordinates, such as interatomic distances or individual dihedral angles, have been shown to select out for the corresponding interactions, annihilating other interactions in the potential expression. Exploitation of these quantities allows one to probe the individual interaction and explore phenomena such as, for example, anisotropy of atom-atom nonbonded interactions, charge flux, or the functional form of isolated dihedral angles, e.g., a single dihedral X-C-C-Y about a tetrahedral C-C bond. PMID:26642978

  17. Global Aerosol Climatology Project.

    NASA Astrophysics Data System (ADS)

    Mishchenko, Michael; Penner, Joyce; Anderson, Donald

    2002-02-01

    This paper is concerned with uncertainties in the Advanced Very High Resolution Radiometer (AVHRR)-based retrieval of optical depth for heavy smoke aerosol plumes generated from forest fires that occurred in Canada due to a lack of knowledge on their optical properties (single-scattering albedo and asymmetry parameter). Typical values of the optical properties for smoke aerosols derived from such field experiments as Smoke, Clouds, and Radiation-Brazil (SCAR-B); Transport and Atmospheric Chemistry near the Equator-Atlantic (TRACE-A); Biomass Burning Airborne and Spaceborne Experiment in the Amazonas (BASE-A); and Boreal Ecosystem-Atmosphere Study (BOREAS) were first assumed for retrieving smoke optical depths. It is found that the maximum top-of-atmosphere (TOA) reflectance values calculated by models with these aerosol parameters are less than observations whose values are considerably higher. A successful retrieval would require an aerosol model that either has a substantially smaller asymmetry parameter (g < 0.4 versus g > 0.5), or higher single-scattering albedo ( 0.9 versus < 0.9), or both (e.g., g = 0.39 and = 0.91 versus g = 0.57 and = 0.87) than the existing models. Several potential causes were examined including small smoke particle size, low black carbon content, humidity effect, calibration errors, inaccurate surface albedo, mixture of cloud and aerosol layers, etc. A more sound smoke aerosol model is proposed that has a lower content of black carbon (mass ratio = 0.015) and smaller size (mean radius = 0.02 m for dry smoke particles), together with consideration of the effect of relative humidity. Ground-based observations of smoke suggest that for < 2.5 there is an increasing trend in and a decreasing trend in g with increases in , which is consistent with the results of satellite retrievals. Using these relationships as constraints, more plausible values of can be obtained for heavy smoke aerosol. The possibility of smoke-cloud mixtures is also

  18. Climatology of POLDER/PARASOL cloud properties

    NASA Astrophysics Data System (ADS)

    Parol, F.; Riedi, J.; Vanbauce, C.; Cornet, C.; Zeng, S.; Thieuleux, F.; Henriot, N.

    2013-05-01

    Since December 2004 the CNES PARASOL (Polarization and Anisotropy of Reflectances for Atmospheric Science coupled with Observations from a Lidar) mission has been flying in the A-Train constellation. More than seven years of data have been routinely acquired and processed by the PARASOL/POLDER ground segment (CNES) and by ICARE Data Center in Lille, France. PARASOL's unique spectral, directional and polarization capabilities give powerful constraints to the cloud retrieval scheme. They allow derivation of classical cloud properties (amount, optical depth, altitude or pressure, albedo) with state of the art performance but also provide original information (thermodynamic phase, angular variability of properties, heterogeneity parameter, etc.). Climatology of cloud fraction and cloud optical thickness have been realized over the 2005-2011 period. Some results and comparisons to MODIS are shown for the year 2008.

  19. GMS-5 Satellite-Derived Cloud Properties Over the Tropical Western Pacific

    NASA Technical Reports Server (NTRS)

    Nordeen, M. L.; Doelling, D. R.; Khaiyer, M. M.; Rapp, A. D.; Minnis, P.; Nguyen, L.

    2001-01-01

    Satellite monitoring is used to supplement the paucity of surface data in the Tropical Western Pacific (TWP). By using satellite data, cloud properties and top-of-atmosphere broadband radiative fluxes can be derived and used for a variety of applications. In turn, these products may be used to develop a climatological base for the TWP. The focus of this study is to produce satellite-derived cloud properties over the TWP.

  20. Deriving Daytime Variables From the AmeriFlux Standard Eddy Covariance Data Set

    SciTech Connect

    van Ingen, Catharine; Agarwal, Deborah A.; Humphrey, Marty; Li, Jie

    2008-12-06

    A gap-filled, quality assessed eddy covariance dataset has recently become available for the AmeriFluxnetwork. This dataset uses standard processing and produces commonly used science variables. This shared dataset enables robust comparisons across different analyses. Of course, there are many remaining questions. One of those is how to define 'during the day' which is an important concept for many analyses. Some studies have used local time — for example 9am to 5pm; others have used thresholds on photosynthetic active radiation (PAR). A related question is how to derive quantities such as the Bowen ratio. Most studies compute the ratio of the averages of the latent heat (LE) and sensible heat (H). In this study, we use different methods of defining 'during the day' for GPP, LE, and H. We evaluate the differences between methods in two ways. First, we look at a number of statistics of GPP. Second, we look at differences in the derived Bowen ratio. Our goal is not science per se, but rather informatics in support of the science.

  1. Thermal performance of multilayer insulation; Part 1, Derivation of a prediction-based heat-flux equation

    SciTech Connect

    Amano, Toshiyuki

    1994-09-01

    How to reduce the heat loss at cryogenic temperatures in superconducting magnets used for MRI (Magnetic Resonance Imaging), magnetically levitated trains, nuclear fusion, etc., is an important subject. The topic is important in providing a superconducting magnet with high-performance thermal insulation. A prediction-based equation for heat flux through a multilayer insulator was derived from comparison of experimental results between room temperature and liquid-nitrogen temperature. The employed multilayer insulator was a laminated material with a polyester net inserted between aluminized Mylar films. The prediction equation consists of one thermal-radiation and two thermal-conduction terms. The first conduction term is that of ordinary thermal-contact conductance. The second conduction term depends on the self-compression of the multilayer insulation. The predicted values resulting from the obtained coincided fairly well with measured values.

  2. TRMM-Based Lightning Climatology

    NASA Technical Reports Server (NTRS)

    Cecil, Daniel J.; Buechler, Dennis E.; Blakeslee, Richard J.

    2011-01-01

    Gridded climatologies of total lightning flash rates seen by the spaceborne Optical Transient Detector (OTD) and Lightning Imaging Sensor (LIS) have been updated. OTD collected data from May 1995 to March 2000. LIS data (equatorward of about 38 deg) has been added for 1998-2010. Flash counts from each instrument are scaled by the best available estimates of detection efficiency. The long LIS record makes the merged climatology most robust in the tropics and subtropics, while the high latitude data is entirely from OTD. The mean global flash rate from the merged climatology is 46 flashes per second. The peak annual flash rate at 0.5 deg scale is 160 fl/square km/yr in eastern Congo. The peak monthly average flash rate at 2.5 scale is 18 fl/square km/mo, from early April to early May in the Brahmaputra Valley of far eastern India. Lightning decreases in this region during the monsoon season, but increases further north and west. A monthly average peak from early August to early September in northern Pakistan also exceeds any monthly averages from Africa, despite central Africa having the greatest yearly average. Most continental regions away from the equator have an annual cycle with lightning flash rates peaking in late spring or summer. The main exceptions are India and southeast Asia, with springtime peaks in April and May. For landmasses near the equator, flash rates peak near the equinoxes. For many oceanic regions, the peak flash rates occur in autumn. This is particularly noticeable for the Mediterranean and North Atlantic. Landmasses have a strong diurnal cycle of lightning, with flash rates generally peaking between 3-5 pm local solar time. The central United States flash rates peak later, in late evening or early night. Flash rates peak after midnight in northern Argentina. These regions are known for large, intense, long-lived mesoscale convective systems.

  3. Seasonal cycles in radium and barium within a subterranean estuary: Implications for groundwater derived chemical fluxes to surface waters

    NASA Astrophysics Data System (ADS)

    Gonneea, Meagan Eagle; Mulligan, Ann E.; Charette, Matthew A.

    2013-10-01

    There is increasing evidence that submarine groundwater discharge (SGD) is an important source of water and dissolved materials to the ocean. One of the primary tracers of this process is the quartet of radium isotopes (223Ra, 224Ra, 226Ra and 228Ra), whereby excess activities in surface waters can often be attributed to an input supplied via SGD. This approach requires the radium end member activity to be well constrained, however, natural variability in groundwater radium may span several orders of magnitude. Therefore, this variability is usually the main driver of uncertainties in volumetric SGD estimates. To investigate the physical and biogeochemical controls on groundwater radium activities, we conducted a three-year time series of radium and barium, a chemical analogue for radium, within the subterranean estuary of a coastal aquifer (Waquoit Bay, MA, USA). Gonneea et al. (2013) demonstrated that movement of the salinity interface within the subterranean estuary is driven by changes in the hydraulic gradient between groundwater level and sea level height. For Waquoit Bay, seasonal scale sea level change, not groundwater level, was the main driver in hydraulic gradient fluctuations. Seasonal changes in groundwater chemistry can be attributed to the resulting movement of the salinity transition zone between terrestrial and marine groundwater. Landward movement of the interface results in a large release of radium isotopes (226Ra = 1400 dpm 100 L-1) and barium (3000 nmol kg-1) associated with an increase in groundwater salinity. The magnitude of these releases cannot be explained by in situ production or weathering alone, but is likely due to salinity driven desorption from surface-bound sediment inventory. The timing of these peak concentrations is not always in phase with model-derived estimates of SGD; as a result, the groundwater concentration rather than the water flux is the main driver of Ra and Ba inputs to Waquoit Bay surface waters. The behavior of

  4. Climatology of lightning in the Czech Republic

    NASA Astrophysics Data System (ADS)

    Novák, Petr; Kyznarová, Hana

    2011-06-01

    The Czech Hydrometeorological Institute (CHMI) has utilized lightning data from the Central European Lightning Detection Network (CELDN) since 1999. The CELDN primarily focuses on the detection of cloud-to-ground (CG) lightning but intra-cloud (IC) lightning detection is also available. Lightning detection is used by the CHMI forecasters as an additional source to radar and satellite data for nowcasting of severe storms. Lightning data are also quantitatively used in automatic nowcasting applications. The quality of lightning data can be evaluated using their climatological characteristics. Climatological characteristics are also useful for defining decision thresholds that are valuable for human forecasters as well as for automatic nowcasting applications. The seven-year period from 2002 to 2008, which had relatively even-quality lightning data, was used to calculate the spatial and temporal distributions of lightning. The monthly number of CG strokes varies depending on the season. The highest number of CG strokes occurs during summer, with more than 20 days of at least five detected CG strokes on the Czech Republic territory in June and July. The least number of CG stokes occurs in winter, with less than three days per month having at least five detected CG stokes. The mean diurnal distribution of CG strokes peaks between 1500 and 1600 UTC and reaches a minimum between 0500 and 0800 UTC. The average spatial distribution of CG strokes shows sharp local maxima corresponding with the locations of the TV broadcast towers. The average spatial distribution of CG flash density, calculated on a 20 × 20 km grid, shows the maximum (3.23 flashes km - 2 year - 1 ) in the western part of Czech Republic and the minimum (0.92 flashes km - 2 year - 1 ) in the south-southeast of the Czech Republic. In addition, lightning characteristics related to the identified convective cells, such as distribution of the lightning stroke rates or relation to the radar derived by Vertically

  5. Spectrally Resolved Flux Derived from Collocated AIRS and CERES Observations and its Application in Model Validation. Part I; Clear-Sky Over the Tropic Oceans

    NASA Technical Reports Server (NTRS)

    Huang, Xianglei; Yang, Wenze; Loeb, Norman G.; Ramaswamy, V.

    2008-01-01

    Spectrally resolved outgoing IR flux, the integrand of the outgoing longwave radiation (OLR), has its unique value in evaluating model simulations. Here we describe an algorithm of deriving such clear-sky outgoing spectral flux through the whole IR region from the collocated Atmospheric Infrared Sounder (AIRS) and the Clouds & the Earth's Radiant Energy System (CERES) measurements over the tropical oceans. Based on the scene types and corresponding angular distribution models (ADMs) used in the CERES Single Satellite Footprint (SSF) dataset, spectrally-dependent ADMs are developed and used to estimate the spectral flux at each AIRS channel. A multivariate linear prediction scheme is then used to estimate spectral fluxes at frequencies not covered by the AIRS instrument. The whole algorithm is validated using synthetic spectra as well as the CERES OLR measurements. Using the GFDL AM2 model simulation as a case study, the application of the derived clear-sky outgoing spectral flux in model evaluation is illustrated. By comparing the observed and simulated spectral flux in 2004, compensating errors in the simulated OLR from different absorption bands can be revealed, so does the errors from frequencies within a given absorption band. Discrepancies between the simulated and observed spatial distributions and seasonal evolutions of the spectral fluxes at different spectral ranges are further discussed. The methodology described in this study can be applied to other surface types as well as cloudy-sky observations and corresponding model evaluations.

  6. 30 CFR 779.18 - Climatological information.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Climatological information. 779.18 Section 779... PROGRAMS SURFACE MINING PERMIT APPLICATIONS-MINIMUM REQUIREMENTS FOR INFORMATION ON ENVIRONMENTAL RESOURCES § 779.18 Climatological information. (a) When requested by the regulatory authority, the...

  7. 30 CFR 783.18 - Climatological information.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Climatological information. 783.18 Section 783... PROGRAMS UNDERGROUND MINING PERMIT APPLICATIONS-MINIMUM REQUIREMENTS FOR INFORMATION ON ENVIRONMENTAL RESOURCES § 783.18 Climatological information. (a) When requested by the regulatory authority,...

  8. Carbon-Flux Distribution within Streptomyces coelicolor Metabolism: A Comparison between the Actinorhodin-Producing Strain M145 and Its Non-Producing Derivative M1146

    PubMed Central

    Coze, Fabien; Gilard, Françoise; Tcherkez, Guillaume; Virolle, Marie-Joëlle; Guyonvarch, Armel

    2013-01-01

    Metabolic Flux Analysis is now viewed as essential to elucidate the metabolic pattern of cells and to design appropriate genetic engineering strategies to improve strain performance and production processes. Here, we investigated carbon flux distribution in two Streptomyces coelicolor A3 (2) strains: the wild type M145 and its derivative mutant M1146, in which gene clusters encoding the four main antibiotic biosynthetic pathways were deleted. Metabolic Flux Analysis and 13C-labeling allowed us to reconstruct a flux map under steady-state conditions for both strains. The mutant strain M1146 showed a higher growth rate, a higher flux through the pentose phosphate pathway and a higher flux through the anaplerotic phosphoenolpyruvate carboxylase. In that strain, glucose uptake and the flux through the Krebs cycle were lower than in M145. The enhanced flux through the pentose phosphate pathway in M1146 is thought to generate NADPH enough to face higher needs for biomass biosynthesis and other processes. In both strains, the production of NADPH was higher than NADPH needs, suggesting a key role for nicotinamide nucleotide transhydrogenase for redox homeostasis. ATP production is also likely to exceed metabolic ATP needs, indicating that ATP consumption for maintenance is substantial.Our results further suggest a possible competition between actinorhodin and triacylglycerol biosynthetic pathways for their common precursor, acetyl-CoA. These findings may be instrumental in developing new strategies exploiting S. coelicolor as a platform for the production of bio-based products of industrial interest. PMID:24376790

  9. A solely radiance-based spectral anisotropic distribution model and its application in deriving clear-sky spectral fluxes

    NASA Astrophysics Data System (ADS)

    Song, L.; Huang, X.

    2011-12-01

    Anisotropic distribution model (ADM) plays a uniquely central role in converting broadband radiance measurement to broadband flux. Scene type classifications are usually needed for such ADM and such classifications are usually done with auxiliary measurements and information since broadband radiance does not contain detailed information about temperature, humidity, and clouds. Recently Huang et al. (2008 and 2010) has developed spectral ADM based on such scene type classifications and successfully derived spectral flux from spectral radiance measurement. Unlike broadband radiances, the spectrally resolved radiances indeed contain rich information about temperature, humidity, and clouds. Therefore, it is meaningful to explore whether it is possible to develop scene-type classification solely based on spectral radiance and consequently to construct spectral ADM solely base on radiances measurement. Using AIRS spectrum as an example, here we develop a clear-sky scene classification algorithm solely based on AIRS radiances. The definitions of scene types are similar to those of clear-sky scene types used in CERES SSF algorithm, which are discrete intervals based on surface skin temperature, lapse rate (temperature change of the first 300 mb above the surface), and the total precipitable water (TPW). Brightness temperature of AIRS channel at 963.8 cm-1 are used for determine corresponding discrete intervals of surface skin temperature. This channel is also used in conjunction with a channel at 748.6 cm-1 for categorizing the lapse rate. Given the slow varying of water vapor continuum in the window region and the dominant weight of lower tropospheric humidity in TPW, a double-differential technique is used to categorize the TPW. By choosing two pairs of AIRS channels with similar frequency intervals, the technique can classify the TPW without any a priori information about continuum absorption since double differencing largely remove the slow-varying continuum

  10. Comparative climatology - Mars and earth

    NASA Technical Reports Server (NTRS)

    Haberle, R. M.

    1985-01-01

    Spacecraft missions to Mars during the 1960's and 1970's gave a remarkably detailed picture of the meteorological and climatological conditions that characterize its atmosphere. During the relatively brief history of close-up exploration of Mars, much of the ambiguity associated with the early telescopic observations has been resolved, and a new image of the red planet has emerged. Accurate measurements taken both from orbit and the surface reveal a cool, thin atmosphere that condenses, transports water, and generates clouds and dust storms, and that has a global-scale wind system not unlike the one known on earth. This paper highlights the current view of the Martian climate system and what controls it. For perspective, comparisons with earth's climate system are included where appropriate.

  11. Uncertainty in Climatology-Based Estimates of Soil Water Infiltration Losses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Local climatology is often used to estimate infiltration losses at the field scale. The objective of this work was to assess the uncertainty associated with such estimates. We computed infiltration losses from the water budget of a soil layer from monitoring data on water flux values at the soil su...

  12. Enhanced production of resveratrol derivatives in tobacco plants by improving the metabolic flux of intermediates in the phenylpropanoid pathway.

    PubMed

    Jeong, Yu Jeong; An, Chul Han; Woo, Su Gyeong; Park, Ji Hye; Lee, Ki-Won; Lee, Sang-Hoon; Rim, Yeonggil; Jeong, Hyung Jae; Ryu, Young Bae; Kim, Cha Young

    2016-09-01

    The biosynthesis of flavonoids such as anthocyanin and stilbenes has attracted increasing attention because of their potential health benefits. Anthocyanins and stilbenes share common phenylpropanoid precursor pathways. We previously reported that the overexpression of sweetpotato IbMYB1a induced anthocyanin pigmentation in transgenic tobacco (Nicotiana tabacum) plants. In the present study, transgenic tobacco (Nicotiana tabacum SR1) plants (STS-OX and ROST-OX) expressing the RpSTS gene encoding stilbene synthase from rhubarb (Rheum palmatum L. cv. Jangyeop) and the RpSTS and VrROMT genes encoding resveratrol O-methyltransferase from frost grape (Vitis riparia) were generated under the control of 35S promoter. Phenotypic alterations in floral organs, such as a reduction in floral pigments and male sterility, were observed in STS-OX transgenic tobacco plants. However, we failed to obtain STS-OX and ROST-OX plants with high levels of resveratrol compounds. Therefore, to improve the production of resveratrol derivatives in plants, we cross-pollinated flowers of STS-OX or ROST-OX and IbMYB1a-OX transgenic lines (SM and RSM). Phenotypic changes in vegetative and reproductive development of SM and RSM plants were observed. Furthermore, by HPLC and LC-MS analyses, we found enhanced production of resveratrol derivatives such as piceid, piceid methyl ether, resveratrol methyl ether O-hexoside, and 5-methyl resveratrol-3,4'-O-β-D-diglucopyranoside in SM and RSM cross-pollinated lines. Here, total contents of trans- and cis-piceids ranged from approximately 104-240 µg/g fresh weight in SM (F2). Collectively, we suggest that coexpression of RpSTS and IbMYB1a via cross-pollination can induce enhanced production of resveratrol compounds in plants by increasing metabolic flux into stilbenoid biosynthesis. PMID:27338256

  13. Conference on Applied Climatology, 6th, Charleston, SC, Mar. 7-10, 1989, Preprints

    SciTech Connect

    Not Available

    1989-01-01

    Papers on applied climatology are presented, covering topics such as climate resources, precipitation climatology and land use planning, urbanization and rainfall distribution, climate changes, heat stress climatology, climate and culture, climate and agriculture, studies of the 1988 drought, and climatic records. Papers are included on orography and precipitation variability, climate scenarios for impact assessment, temperature changes and the greenhouse effect, the relationship between a GCM simulated climate and the observed local climate, a synoptic approach to the detection of climatic change, and climate modeling with a limited area model coupled to a GCM. Other topics include high-resolution ground-based remote sensors, the application of a spatial synoptic climatological index to changes in atmospheric NO{sub 2} and SO{sub 2} concentrations, thunderstorm and lightning relationships, satellite-derived vegetation indices as indicators of climatic variability, and the relationships between precipitation and 700 mb height patterns.

  14. Investigation of gravity wave activity based on operational radiosonde data from 13 years (1997-2009): Climatology and possible induced variability

    NASA Astrophysics Data System (ADS)

    Kramer, R.; Wüst, S.; Bittner, M.

    2016-03-01

    Atmospheric gravity waves (GWs) are important for the dynamics of the atmosphere. The analysis of 13 years of routine radiosonde data from Prague (50.01°N, 14.27°E) with temporal highly resolved temperature, pressure and wind measurements is presented in order to derive a climatology of gravity wave activity in the lower stratosphere. An annual cycle with a maximum during winter and a minimum during summer is identified. Gravity wave activity is twice as high during winter as during summer. Winter periods are investigated by wavelet analysis. They show similar periods in vertical flux of horizontal momentum and pressure variance time series. These features may be attributed to planetary waves. When analyzing individual years, maxima of gravity wave activity and vertical flux of horizontal momentum often appears together with minima in surface pressure. We speculate therefore that at least parts of the interannual variations of gravity wave activity may due to cyclones.

  15. Climatological assessment of recent severe weather events

    SciTech Connect

    Changnon, D.; Changnon, S.A.

    1997-11-01

    A climatological assessment of a series of exceptionally severe and damaging storms during 1991-1994 was pursued to put these events and their frequency and intensity/severity into a temporal perspective. The severe weather events were assessed according to the damage they caused. Insurance-derived measures of property and crop losses due to weather were used in this study; these measures adjust individual storm losses to changing socioeconomic conditions. Two methods were used to assess the events: (1) a comparative analysis of event frequency, losses and intensity with those in the preceding 40 years, and (2) a comparison of temporal variations of the 1949-1994 events with fluctuations in population, cyclonic activity, and temperatures. The results showed that the 1991-1994 property losses ranked high in number and amount of loss. However, storm intensity was found to be higher in the 1950s. The temporal distributions of the catastrophes and crop losses were well related to North American cyclonic activity, and when cyclonic activity, U.S. mean temperatures, and population were combined, they explained 865 of the variability found in the frequency of catastrophes during 1949-1994. The results suggest that, although the severe weather events in 1991-1994 were exceptionally high in frequency and losses, much of the loss was a result of the ever increasing target at risk. 9 refs., 7 figs., 1 tab.

  16. Corn yield prediction using climatology

    SciTech Connect

    Duchon, C.E.

    1986-05-01

    A method is developed to predict corn yield during the growing season using a plant process model (CERES-Maize), current weather data and climatological data. The procedure is to place the current year's daily weather (temperature and precipitation) into the model up to the time the yield prediction is to be made and sequences of historical data (one sequence per year) after that time until the end of the growing season to produce yield estimates. The mean of the distribution of yield estimates is taken as the prediction. The variance associated with a prediction is relatively constant until the time of tassel initiation and then decreases toward zero as the season progresses. As a consequence, perfect weather forecasts reach their peak value between the beginning of ear growth and the beginning of grain fill. The change in the predicted yield in response to weather as the growing season progresses is discussed for 1983 and 1976 at Peoria, Illinois. Results are given of an attempt to incorporate 30-day Climate Analytic Center outlooks into the predictive scheme. 21 references, 14 figures, 1 table.

  17. Concentration and vertical flux of Fukushima-derived radiocesium in sinking particles from two sites in the Northwestern Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Honda, M. C.; Kawakami, H.; Watanabe, S.; Saino, T.

    2013-06-01

    At two stations in the western North Pacific, K2 in the subarctic gyre and S1 in the subtropical gyre, time-series sediment traps were collecting sinking particles when the Fukushima Daiichi Nuclear Power Plant (FNPP1) accident occurred on 11 March 2011. Radiocesium (134Cs and 137Cs) derived from the FNPP1 accident was detected in sinking particles collected at 500 m in late March 2011 and at 4810 m in early April 2011 at both stations. The sinking velocity of 134Cs and 137Cs was estimated to be 22 to 71 m day-1 between the surface and 500 m and >180 m day-1 between 500 m and 4810 m. 137Cs concentrations varied from 0.14 to 0.25 Bq g-1 dry weight. These values are higher than those of surface seawater, suspended particles, and zooplankton collected in April 2011. Although the radiocesium may have been adsorbed onto or incorporated into clay minerals, correlations between 134Cs and lithogenic material were not always significant; therefore, the form of the cesium associated with the sinking particles is still an open question. The total 137Cs inventory by late June at K2 and by late July at S1 was 0.5 to 1.7 Bq m-2 at both depths. Compared with 137Cs input from both stations by April 2011, estimated from the surface 137Cs concentration and mixed-layer depth and by assuming that the observed 137Cs flux was constant throughout the year, the estimated removal rate of 137Cs from the upper layer (residence time in the upper layer) was 0.3 to 1.5% yr-1 (68 to 312 yr). The estimated removal rates and residence times are comparable to previously reported values after the Chernobyl accident (removal rate: 0.2-1%, residence time: 130-390 yr).

  18. Chesapeake Bay nitrogen fluxes derived from a land-estuarine ocean biogeochemical modeling system: Model description, evaluation, and nitrogen budgets

    NASA Astrophysics Data System (ADS)

    Feng, Yang; Friedrichs, Marjorie A. M.; Wilkin, John; Tian, Hanqin; Yang, Qichun; Hofmann, Eileen E.; Wiggert, Jerry D.; Hood, Raleigh R.

    2015-08-01

    The Chesapeake Bay plays an important role in transforming riverine nutrients before they are exported to the adjacent continental shelf. Although the mean nitrogen budget of the Chesapeake Bay has been previously estimated from observations, uncertainties associated with interannually varying hydrological conditions remain. In this study, a land-estuarine-ocean biogeochemical modeling system is developed to quantify Chesapeake riverine nitrogen inputs, within-estuary nitrogen transformation processes and the ultimate export of nitrogen to the coastal ocean. Model skill was evaluated using extensive in situ and satellite-derived data, and a simulation using environmental conditions for 2001-2005 was conducted to quantify the Chesapeake Bay nitrogen budget. The 5 year simulation was characterized by large riverine inputs of nitrogen (154 × 109 g N yr-1) split roughly 60:40 between inorganic:organic components. Much of this was denitrified (34 × 109 g N yr-1) and buried (46 × 109 g N yr-1) within the estuarine system. A positive net annual ecosystem production for the bay further contributed to a large advective export of organic nitrogen to the shelf (91 × 109 g N yr-1) and negligible inorganic nitrogen export. Interannual variability was strong, particularly for the riverine nitrogen fluxes. In years with higher than average riverine nitrogen inputs, most of this excess nitrogen (50-60%) was exported from the bay as organic nitrogen, with the remaining split between burial, denitrification, and inorganic export to the coastal ocean. In comparison to previous simulations using generic shelf biogeochemical model formulations inside the estuary, the estuarine biogeochemical model described here produced more realistic and significantly greater exports of organic nitrogen and lower exports of inorganic nitrogen to the shelf.

  19. Climatological data summary 1993 with historical data

    SciTech Connect

    Hoitink, D.J.; Burk, K.W.

    1994-06-01

    This document presents the climatological data summary for calendar year 1993. It presents updated historical climatologies for temperature, wind, precipitation, and other miscellaneous meteorological parameters from the Hanford Meteorology Station (HMS) and Hanford Meteorological Monitoring Network. It also presents climatological normal and extreme values of temperature and precipitation for the HMS. Previous documents have included climatological data collected at the old Hanford Townsite, located approximately 10 miles east-northeast of the present HMS. The records for these two different sites have been frequently interchanged as if representing the same location. With the exception of Section 2.0, the remainder of this document uses data only from the HMS, with a period of record beginning December 7, 1944.

  20. Seasonal export fluxes of size-fractionated particulate derived from polonium-210: A case study in Xiamen Bay

    NASA Astrophysics Data System (ADS)

    Yang, Weifeng; Huang, Yipu; Chen, Min; Qiu, Yusheng

    2010-03-01

    Size-fractionated 210Po and 210Pb, in the size fractions >0.4 μm, >2 μm and >10 μm, were examined to determine the seasonal variability of particulate fluxes in Xiamen Bay. Good correlations between 210Po and particulate organic carbon (POC) or non-Particulate Organic Matter (nPOM) suggested that 210Po can be used to trace the export fluxes of POC and nPOM. Both steady-state (SS) model and nSS model were used to evaluate fluxes of size-fractionated 210Po, results showed that nSS model was better than the SS model in coastal areas. Based on the nSS model, size-fractionated POC fluxes decreased with increasing particle size. For the particle size studied, maximum POC fluxes occurred in autumn, followed by spring, winter, and summer. Fluxes of nPOM were an order of magnitude higher than the corresponding size-fractionated POC fluxes. Differences between size-fractionated nPOM fluxes indicated that hydrodynamic conditions were the main factor regulating transportation of particulate out of the inner Bay. In winter most particulates, including >10 μm particles, were transported under the strongest hydrodynamic conditions. In contrast, only a fraction of the <2 μm particulates were transported from the inner Bay in spring. This study suggested that 210Po is a powerful tracer of seasonal particulate export in coastal seas.

  1. Export Fluxes in Contrasting Environments of the South-East Pacific Ocean Derived From Drifting Sediment traps (BIOSOPE)

    NASA Astrophysics Data System (ADS)

    Miquel, J.; Gasser, B.; Claustre, H.

    2006-12-01

    The South-East Pacific presents contrasting oceanographic environments related to different oceanographic features such as High Nutrient Low Chlorophyl (HNLC) zones, upwelling of eastern boundaries or ultra- oligotrophy of the central gyre. This results in significant differences in particle production in surface waters and export to the deeper ocean. During the BIOSOPE (BIogeochemistry and Optics SOuth Pacific Experiment) cruise held in October-December 2004, particle flux in upper waters was assessed using drifting sediment traps. Traps were deployed at 2 depths (below the maximum chl.a and at the base of the euphotic layer) in six geographical areas, ranging from the oligotrophic central gyre through the mesotrophic area off Marquesas Islands to the eutrophic waters off the South-American coast. For all analyzed parameters fluxes were contrastingly different at the various sites, with lowest fluxes at the central gyre area and highest fluxes at the upwelling sites. Mass flux ranged from 2-7 mg m-2 d-1 to 410-630 mg m-2 d-1, POC flux from less than 1 mg POC m-2 d-1 up to 63 mg POC m^{- 2} d-1, and Th-234 from 35-47 dpm m-2 d-1 to >5000 dpm m-2 d-1. Fluxes were always lower at the deeper horizon except for Th-234 flux which was variable. Also, fluxes were very different at the two upwelling sites studied. The relation between the environmental and trophic characteristics of the sites visited and the two orders of magnitude in fluxes observed is discussed.

  2. Surface Energy Heat Fluxes Using Remotely Sensed Parameters

    NASA Technical Reports Server (NTRS)

    Toll, David L.; Vukovich, Fred M.; Pontikes, Elizabeth G.

    1997-01-01

    Realistic estimates of surface energy heat fluxes are needed for the study of water and energy interactions between the land and atmosphere. The primary objective of this work is to study the estimation of surface heat energy fluxes using remote sensing derived parameters under different spatial and temporal conditions. Surface energy fluxes and remote sensing derived data from two sources were analyzed. First, we used surface heat flux, remote sensing, and ancillary data from the International Satellite Land Surface Climatology Project (ISLSCP), mapped at a 1 deg. x 1 deg. grid. Second, we used NOAA AVHRR (1 km), weather station, and ancillary data to derive estimates of surface latent and sensible heat energy fluxes over a 100 sq kilometers area for three test sites: 1) First ISLSCP Field Experiment (FIFE) grassland site, Konza Prairie, Kansas; 2) Howland, Maine Forest Ecosystem Dynamics Site; and 3) Walnut Gulch, scrubland site, surrounding Tombstone, Arizona. Satellite derived estimates of land surface temperature, surface albedo, and spectral vegetation index are used in selected models to provide estimates of surface heat fluxes. Analysis of results from the 1 deg. x 1 deg. grid for North America indicated there were similar, overall correlations between sensible and latent heat energy fluxes versus remotely sensed vegetation index and ground temperature during dry and wet year conditions. However, there were significant differences in correlations between years when stratified by land cover class. Analysis of 100 km x 100 km data (1 km resolution) indicated partitioning the areas in to primary versus secondary cover, with the secondary cover comprising less than 5% of the area, significantly improved surface heat energy flux estimates.

  3. Phenological indicators derived with CO2 flux, MODIS image and ground monitor at a temperate mixed forest and an alpine shrub

    NASA Astrophysics Data System (ADS)

    Zhang, Leiming; Cao, Peiyu; Li, Shenggong; Yu, Guirui; Zhang, Junhui; Li, Yingnian

    2016-04-01

    To accurately assess the change of phenology and its relationship with ecosystem gross primary productivity (GPP) is one of the key issues in context of global change study. In this study, an alpine shrubland meadow in Haibei (HBS) of Qinghai-Tibetan plateau and a broad-leaved Korean pine forest in Changbai Mountain (CBM) of Northeastern China were selected. Based on the long-term GPP from eddy flux measurements and the Normalized Difference Vegetation Index (NDVI) from remote sensed vegetation index, phenological indicators including the start of growing season (SOS), the end of growing season (EOS), and the growing season length (GSL) since 2003 were derived via multiple methods, and then the influences of phenology variation on GPP were explored. Compared with ground phenology observations of dominant plant species, both GPP- and NDVI-derived SOS and EOS exhibited a similar interannual trend. GPP-derived SOS was quite close to NDVI-derived SOS, but GPP-derived EOS differed significantly from NDVI-derived EOS, and thus leading to a significant difference between GPP- and NDVI-derived GSL. Relative to SOS, EOS presented larger differences between the extraction methods, indicating large uncertainties to accurately define EOS. In general, among the methods used, the threshold methods produced more satisfactory assessment on phenology change. This study highlights that how to harmonize with the flux measurements, remote sensing and ground monitoring are a big challenge that needs further consideration in phenology study, especially the accurate extraction of EOS. Key words: phenological variation, carbon flux, vegetation index, vegetation grwoth, interannual varibility

  4. Tennessee Valley Total and Cloud-to-Ground Lightning Climatology Comparison

    NASA Technical Reports Server (NTRS)

    Buechler, Dennis; Blakeslee, R. J.; Hall, J. M.; McCaul, E. W.

    2008-01-01

    The North Alabama Lightning Mapping Array (NALMA) has been in operation since 2001 and consists often VHF receivers deployed across northern Alabama. The NALMA locates sources of impulsive VHF radio signals from total lightning by accurately measuring the time that the signals arrive at the different receiving stations. The sources detected are then clustered into flashes by applying spatially and temporally constraints. This study examines the total lightning climatology of the region derived from NALMA and compares it to the cloud-to-ground (CG) climatology derived from the National Lightning Detection Network (NLDN) The presentation compares the total and CG lightning trends for monthly, daily, and hourly periods.

  5. Biomes computed from simulated climatologies

    SciTech Connect

    Claussen, M.; Esch, M.

    1994-01-01

    The biome model of Prentice et al. is used to predict global patterns of potential natural plant formations, or biomes, from climatologies simulated by ECHAM, a model used for climate simulations at the Max-Planck-Institut fuer Meteorologie. This study undertaken in order to show the advantage of this biome model in diagnosing the performance of a climate model and assessing effects of past and future climate changes predicted by a climate model. Good overall agreement is found between global patterns of biomes computed from observed and simulated data of present climate. But there are also major discrepancies indicated by a difference in biomes in Australia, in the Kalahari Desert, and in the Middle West of North America. These discrepancies can be traced back to in simulated rainfall as well as summer or winter temperatures. Global patterns of biomes computed from an ice age simulation reveal that North America, Europe, and Siberia should have been covered largely by tundra and taiga, whereas only small differences are for the tropical rain forests. A potential northeast shift of biomes is expected from a simulation with enhanced CO{sub 2} concentration according to the IPCC Scenario A. Little change is seen in the tropical rain forest and the Sahara. Since the biome model used is not capable of predicting chances in vegetation patterns due to a rapid climate change, the latter simulation to be taken as a prediction of chances in conditions favourable for the existence of certain biomes, not as a reduction of a future distribution of biomes. 15 refs., 8 figs., 2 tabs.

  6. Nimbus-7 global cloud climatology. II - First year results

    NASA Technical Reports Server (NTRS)

    Stowe, Larry L.; Yeh, H. Y. Michael; Wellemeyer, Charlie G.; Eck, Thomas F.; Kyle, H. Lee

    1989-01-01

    Results are presented on the analysis of the Nimbus-7 satellite data set obtained on regional and seasonal variations in global cloud cover. Four midseason months (April, July, and October 1979 and January 1980) were analyzed for the total cloud amount, the cloud amounts at high, middle, and low altitudes, the cirrus and deep convective clouds, and the cloud and clear-sky 11.5 micron-derived radiances; in addition, noon versus midnight cloud amounts were examined. The Nimbus-7 data are compared with three previously published cloud climatologies, and the differences among these data sets are discussed.

  7. Moisture flux changes and trends for the entire Arctic in 2003-2011 derived from EOS Aqua data

    NASA Astrophysics Data System (ADS)

    Boisvert, L. N.; Markus, T.; Vihma, T. P.

    2013-12-01

    The Arctic sea ice acts as a barrier between the ocean and lower atmosphere, reducing the exchange of heat and moisture. In recent years the ice pack has undergone many changes, in particular a rapid reduction in sea ice extent and compactness in summer and autumn. This, along with modeling studies, would cause one to believe that the moisture flux would be increasing. We estimate the daily moisture flux from 2003-2011 using geophysical data from multiple sensors onboard NASA's Aqua satellite, taking advantage of observations being collected at the same time and along the same track. Our findings show the moisture flux, averaged over the entire Arctic, has had large interannual variations. Increases in air specific humidity tend to reduce the moisture flux, whereas the decrease in sea ice cover tends to increase the flux. Statistically significant seasonal decreasing trends are seen in December, January and February because of the dominating effect of increase in 2m air specific humidity increasing, reducing the surface-air specific humidity difference by -0.0547 kg/kg in the Kara/Barents Seas, E. Greenland Sea and Baffin Bay regions where there is some open water year round. Our results also show that the contribution of the sea ice zone to the total moisture flux has increased by 3.6% because the amount of open water within the sea ice has increased by 4.3%.

  8. A global satellite-assisted precipitation climatology

    NASA Astrophysics Data System (ADS)

    Funk, C.; Verdin, A.; Michaelsen, J.; Peterson, P.; Pedreros, D.; Husak, G.

    2015-10-01

    Accurate representations of mean climate conditions, especially in areas of complex terrain, are an important part of environmental monitoring systems. As high-resolution satellite monitoring information accumulates with the passage of time, it can be increasingly useful in efforts to better characterize the earth's mean climatology. Current state-of-the-science products rely on complex and sometimes unreliable relationships between elevation and station-based precipitation records, which can result in poor performance in food and water insecure regions with sparse observation networks. These vulnerable areas (like Ethiopia, Afghanistan, or Haiti) are often the critical regions for humanitarian drought monitoring. Here, we show that long period of record geo-synchronous and polar-orbiting satellite observations provide a unique new resource for producing high-resolution (0.05°) global precipitation climatologies that perform reasonably well in data-sparse regions. Traditionally, global climatologies have been produced by combining station observations and physiographic predictors like latitude, longitude, elevation, and slope. While such approaches can work well, especially in areas with reasonably dense observation networks, the fundamental relationship between physiographic variables and the target climate variables can often be indirect and spatially complex. Infrared and microwave satellite observations, on the other hand, directly monitor the earth's energy emissions. These emissions often correspond physically with the location and intensity of precipitation. We show that these relationships provide a good basis for building global climatologies. We also introduce a new geospatial modeling approach based on moving window regressions and inverse distance weighting interpolation. This approach combines satellite fields, gridded physiographic indicators, and in situ climate normals. The resulting global 0.05° monthly precipitation climatology, the Climate

  9. New dynamic NNORSY ozone profile climatology

    NASA Astrophysics Data System (ADS)

    Kaifel, A. K.; Felder, M.; Declercq, C.; Lambert, J.-C.

    2012-01-01

    Climatological ozone profile data are widely used as a-priori information for total ozone using DOAS type retrievals as well as for ozone profile retrieval using optimal estimation, for data assimilation or evaluation of 3-D chemistry-transport models and a lot of other applications in atmospheric sciences and remote sensing. For most applications it is important that the climatology represents not only long term mean values but also the links between ozone and dynamic input parameters. These dynamic input parameters should be easily accessible from auxiliary datasets or easily measureable, and obviously should have a high correlation with ozone. For ozone profile these parameters are mainly total ozone column and temperature profile data. This was the outcome of a user consultation carried out in the framework of developing a new, dynamic ozone profile climatology. The new ozone profile climatology is based on the Neural Network Ozone Retrieval System (NNORSY) widely used for ozone profile retrieval from UV and IR satellite sounder data. NNORSY allows implicit modelling of any non-linear correspondence between input parameters (predictors) and ozone profile target vector. This paper presents the approach, setup and validation of a new family of ozone profile climatologies with static as well as dynamic input parameters (total ozone and temperature profile). The neural network training relies on ozone profile measurement data of well known quality provided by ground based (ozonesondes) and satellite based (SAGE II, HALOE, and POAM-III) measurements over the years 1995-2007. In total, four different combinations (modes) for input parameters (date, geolocation, total ozone column and temperature profile) are available. The geophysical validation spans from pole to pole using independent ozonesonde, lidar and satellite data (ACE-FTS, AURA-MLS) for individual and time series comparisons as well as for analysing the vertical and meridian structure of different modes of

  10. A global satellite assisted precipitation climatology

    USGS Publications Warehouse

    Funk, Christopher C.; Verdin, Andrew P.; Michaelsen, Joel C.; Pedreros, Diego; Husak, Gregory J.; Peterson, P.

    2015-01-01

    Accurate representations of mean climate conditions, especially in areas of complex terrain, are an important part of environmental monitoring systems. As high-resolution satellite monitoring information accumulates with the passage of time, it can be increasingly useful in efforts to better characterize the earth's mean climatology. Current state-of-the-science products rely on complex and sometimes unreliable relationships between elevation and station-based precipitation records, which can result in poor performance in food and water insecure regions with sparse observation networks. These vulnerable areas (like Ethiopia, Afghanistan, or Haiti) are often the critical regions for humanitarian drought monitoring. Here, we show that long period of record geo-synchronous and polar-orbiting satellite observations provide a unique new resource for producing high resolution (0.05°) global precipitation climatologies that perform reasonably well in data sparse regions. Traditionally, global climatologies have been produced by combining station observations and physiographic predictors like latitude, longitude, elevation, and slope. While such approaches can work well, especially in areas with reasonably dense observation networks, the fundamental relationship between physiographic variables and the target climate variables can often be indirect and spatially complex. Infrared and microwave satellite observations, on the other hand, directly monitor the earth's energy emissions. These emissions often correspond physically with the location and intensity of precipitation. We show that these relationships provide a good basis for building global climatologies. We also introduce a new geospatial modeling approach based on moving window regressions and inverse distance weighting interpolation. This approach combines satellite fields, gridded physiographic indicators, and in situ climate normals. The resulting global 0.05° monthly precipitation climatology, the Climate

  11. Technical Note: A simple calculation algorithm to separate high-resolution CH4 flux measurements into ebullition and diffusion-derived components

    NASA Astrophysics Data System (ADS)

    Hoffmann, M.; Schulz-Hanke, M.; Garcia Alba, J.; Jurisch, N.; Hagemann, U.; Sachs, T.; Sommer, M.; Augustin, J.

    2015-08-01

    Processes driving the production, transformation and transport of methane (CH4) in wetland ecosystems are highly complex. Thus, serious challenges are constitutes in terms of the mechanistic process understanding, the identification of potential environmental drivers and the calculation of reliable CH4 emission estimates. We present a simple calculation algorithm to separate open-water CH4 fluxes measured with automatic chambers into diffusion- and ebullition-derived components, which helps facilitating the identification of underlying dynamics and potential environmental drivers. Flux separation is based on ebullition related sudden concentration changes during single measurements. A variable ebullition filter is applied, using the lower and upper quartile and the interquartile range (IQR). Automation of data processing is achieved by using an established R-script, adjusted for the purpose of CH4 flux calculation. The algorithm was tested using flux measurement data (July to September 2013) from a former fen grassland site, converted into a shallow lake as a result of rewetting ebullition and diffusion contributed 46 and 55 %, respectively, to total CH4 emissions, which is comparable to those previously reported by literature. Moreover, the separation algorithm revealed a concealed shift in the diurnal trend of diffusive fluxes throughout the measurement period.

  12. A comparison of methods for deriving solute flux rates using long-term data from streams in the mirror lake watershed

    USGS Publications Warehouse

    Bukaveckas, P.A.; Likens, G.E.; Winter, T.C.; Buso, D.C.

    1998-01-01

    Calculation of chemical flux rates for streams requires integration of continuous measurements of discharge with discrete measurements of solute concentrations. We compared two commonly used methods for interpolating chemistry data (time-averaging and flow-weighting) to determine whether discrepancies between the two methods were large relative to other sources of error in estimating flux rates. Flux rates of dissolved Si and SO42- were calculated from 10 years of data (1981-1990) for the NW inlet and Outlet of Mirror Lake and for a 40-day period (March 22 to April 30, 1993) during which we augmented our routine (weekly) chemical monitoring with collection of daily samples. The time-averaging method yielded higher estimates of solute flux during high-flow periods if no chemistry samples were collected corresponding to peak discharge. Concentration-discharge relationships should be used to interpolate stream chemistry during changing flow conditions if chemical changes are large. Caution should be used in choosing the appropriate time-scale over which data are pooled to derive the concentration-discharge regressions because the model parameters (slope and intercept) were found to be sensitive to seasonal and inter-annual variation. Both methods approximated solute flux to within 2-10% for a range of solutes that were monitored during the intensive sampling period. Our results suggest that errors arising from interpolation of stream chemistry data are small compared with other sources of error in developing watershed mass balances.

  13. Observations of the atmospheric boundary layer height over Abu Dhabi, United Arab Emirates: Investigating boundary layer climatology in arid regions

    NASA Astrophysics Data System (ADS)

    Marzooqi, Mohamed Al; Basha, Ghouse; Ouarda, Taha B. M. J.; Armstrong, Peter; Molini, Annalisa

    2014-05-01

    Strong sensible heat fluxes and deep turbulent mixing - together with marked dustiness and a low substrate water content - represent a characteristic signature in the boundary layer over hot deserts, resulting in "thicker" mixing layers and peculiar optical properties. Beside these main features however, desert ABLs present extremely complex local structures that have been scarcely addressed in the literature, and whose understanding is essential in modeling processes such as the transport of dust and pollutants, and turbulent fluxes of momentum, heat and water vapor in hyper-arid regions. In this study, we analyze a continuous record of observations of the atmospheric boundary layer (ABL) height from a single lens LiDAR ceilometer operated at Masdar Institute Field Station (24.4oN, 54.6o E, Abu Dhabi, United Arab Emirates), starting March 2013. We compare different methods for the estimation of the ABL height from Ceilometer data such as, classic variance-, gradient-, log gradient- and second derivation-methods as well as recently developed techniques such as the Bayesian Method and Wavelet covariance transform. Our goal is to select the most suited technique for describing the climatology of the ABL in desert environments. Comparison of our results with radiosonde observations collected at the nearby airport of Abu Dhabi indicate that the WCT and the Bayesian method are the most suitable tools to accurately identify the ABL height in all weather conditions. These two methods are used for the definition of diurnal and seasonal climatologies of the boundary layer conditional to different atmospheric stability classes.

  14. First look at the NOAA Aircraft-based Tropospheric Ozone Climatology

    NASA Astrophysics Data System (ADS)

    Leonard, M.; Petropavlovskikh, I. V.; McClure-Begley, A.; Lin, M.; Tarasick, D.; Johnson, B. J.; Oltmans, S. J.

    2015-12-01

    The Global Greenhouse Gas Reference Network's aircraft program has operated since the 1990s as part of the NOAA Global Monitoring Division network to capture spatial and temporal variability in greenhouse tracers (i.e. CO2, CO, N2O, methane, SF6, halo- and hydro-carbons). Since 2005 the suite of airborne measurements also includes ozone, humidity and temperature profiling through the troposphere (up to 8 km). Light commercial aircraft are equipped with modified 2B Technology ozone monitors (Model 205DB), incorporate temperature and humidity probes, and include global positioning system instrumentation. The dataset was analyzed for tropospheric ozone variability at five continental US stations. As site locations within the Tropospheric Aircraft Ozone Measurement Program have flights only once (four times at one site) a month and begun a decade ago, this raises the question of whether this sampling frequency allows the derivation of an accurate vertical climatology of ozone values. We interpret the representativeness of the vertical and seasonal ozone distribution from aircraft measurements using multi-decadal hindcast simulations conducted with the GFDL AM3 chemistry-climate model. When available, climatology derived from co-located ozone-sonde data will be used for comparisons. The results of the comparisons are analyzed to establish altitude ranges in the troposphere where the aircraft climatology would be deemed to be the most representative. Aircraft-based climatologies are tested from two approaches: comparing the aircraft-based climatology to the daily sampled model and to the subset of model data with matching aircraft dates. Whenever the model and aircraft climatologies show significant seasonal differences, further information is gathered from a seasonal Gaussian distribution plot. We will report on the minimum frequency in flights that can provide adequate climatological representation of seasonal and vertical variability in tropospheric ozone.

  15. A bottom-up approach to derive the closure relation for modelling hydrological fluxes at the watershed scale

    NASA Astrophysics Data System (ADS)

    Vannametee, Ekkamol; Karssenberg, Derek; Hendriks, Martin; Bierkens, Marc

    2014-05-01

    Physically-based hydrological modelling could be considered as an ideal approach for predictions in ungauged basins because observable catchment characteristics can be used to parameterize the model, avoiding model calibration using discharge data, which are not available. Lumped physically-based modelling at the watershed scale is possible with the Representative Elementary Watershed (REW) approach. A key to successful application of this approach is to find a reliable way of developing closure relations to calculate fluxes from different hydrological compartments in the REWs. Here, we present a bottom-up approach as a generic framework to identify the closure relations for particular hydrological processes that are scale-independent and can be directly parameterized using the local-scale observable REW characteristics. The approach is illustrated using the Hortonian runoff as an example. This approach starts from developing a physically-based high-resolution model describing the Hortonian runoff mechanism based on physically-based infiltration theory and runoff generation processes at a local scale. This physically-based model is used to generate a synthetic discharge data set of hypothetical rainfall events and HRUs (6×105 scenarios) as a surrogate for real-world observations. The Hortonian runoff closure relation is developed as a lumped process-based model, consisting of the Green-Ampt equation, a time-lagged linear reservoir model, and three scale-transfer parameters representing the processes within REWs. These scale-transfer parameters are identified by calibrating the closure relations against the synthetic discharge data set for each scenario run, which are, in turn, empirically related to their corresponding observable REW properties and rainstorm characteristics. This results in a parameter library, which allows direct estimation of scaling parameter for arbitrary REWs based on their local-scale observable properties and rainfall characteristics

  16. A 3-year dataset of sensible and latent heat fluxes from the Tibetan Plateau, derived using eddy covariance measurements

    NASA Astrophysics Data System (ADS)

    Li, Maoshan; Babel, Wolfgang; Chen, Xuelong; Zhang, Lang; Sun, Fanglin; Wang, Binbin; Ma, Yaoming; Hu, Zeyong; Foken, Thomas

    2015-11-01

    The Tibetan Plateau (TP) has become a focus of strong scientific interest due to its role in the global water cycle and its reaction to climate change. Regional flux estimates of sensible and latent heat are important variables for linking the energy and hydrological cycles at the TP's surface. Within this framework, a 3-year dataset (2008-2010) of eddy covariance measured turbulent fluxes was compiled from four stations on the TP into a standardised workflow: corrections and quality tests were applied using an internationally comparable software package. Second, the energy balance closure ( C EB) was determined and two different closure corrections applied. The four stations (Qomolangma, Linzhi, NamCo and Nagqu) represent different locations and typical land surface types on the TP (high altitude alpine steppe with sparse vegetation, a densely vegetated alpine meadow, and bare soil/gravel, respectively). We show that the C EB differs between each surface and undergoes seasonal changes. Typical differences in the turbulent energy fluxes occur between the stations at Qomolangma, Linzhi and NamCo, while Nagqu is quite similar to NamCo. Specific investigation of the pre-monsoon, the Tibetan Plateau summer monsoon, post-monsoon and winter periods within the annual cycle reinforces these findings. The energy flux of the four sites is clearly influenced by the Tibetan Plateau monsoon. In the pre-monsoon period, sensible heat flux is the major energy source delivering heat to the atmosphere, whereas latent heat flux is greater than sensible heat flux during the monsoon season. Other factors affecting surface energy flux are topography and location. Land cover type also affects surface energy flux. The energy balance residuum indicates a typically observed overall non-closure in winter, while closure (or `turbulent over-closure') is achieved during the Tibetan Plateau summer monsoon at the Nagqu site. The latter seems to depend on ground heat flux, which is higher in the

  17. Moisture flux changes and trends for the entire Arctic in 2003-2011 derived from EOS Aqua data

    NASA Astrophysics Data System (ADS)

    Boisvert, Linette N.; Markus, Thorsten; Vihma, Timo

    2013-10-01

    The Arctic sea ice acts as a barrier between the ocean and lower atmosphere, reducing the exchange of heat and moisture. In recent years the ice pack has undergone many changes, in particular a rapid reduction in sea ice extent and compactness in summer and autumn. This, along with modeling studies, would cause one to believe that the moisture flux would be increasing. We estimate the daily moisture flux from 2003 to 2011 using geophysical data from multiple sensors onboard NASA's Aqua satellite, taking advantage of observations being collected at the same time and along the same track. Our findings show the moisture flux, averaged over the entire Arctic, has had large interannual variations, with smallest fluxes in 2010, 2003, and 2004, and largest ones in 2007, 2008, and 2005. Increases in air specific humidity tend to reduce the moisture flux, whereas the decrease in sea ice cover tends to increase the flux. Statistically significant seasonal decreasing trends are seen in December, January, and February because of the dominating effect of increase in 2 m air specific humidity increasing, reducing the surface-air specific humidity difference by -0.0547 kg/kg in the Kara/Barents Seas, E. Greenland Sea, and Baffin Bay regions where there is some open water year round. Our results also show that the contribution of the sea ice zone to the total moisture flux (from the open ocean and sea ice zone) has increased by 3.6% because the amount of open water within the sea ice zone has increased by 4.3%.

  18. An assessment of buoy-derived and numerical weather prediction surface heat fluxes in the tropical Pacific

    NASA Astrophysics Data System (ADS)

    Cronin, Meghan F.; Fairall, Christopher W.; McPhaden, Michael J.

    2006-06-01

    As part of the Eastern Pacific Investigation of Climate Processes program, from 2000 through 2003, the easternmost 95°W Tropical Atmosphere Ocean (TAO) moorings were enhanced to provide time series of net surface heat flux, and the National Oceanic and Atmospheric Administration ship maintaining the 95°W and 110°W TAO lines was enhanced to monitor surface heat fluxes and atmospheric boundary layer structure. In this study we compare the ship-based and buoy-based radiative, bulk latent, and sensible heat fluxes, as well as the meteorological state variables used to compute the turbulent heat fluxes. The buoy net surface heat flux measurements appear to have an overall uncertainty near the target 10 W m-2, when careful attention is paid to the state variables. When hourly averaged data were unavailable, the telemetered daily averaged data were used in combination with an estimate of the mesoscale gustiness. In the eastern tropical Pacific a warm layer correction to account for stratification above 1-m depth was important only during the warm season (January-May) near the equator. These high-quality, cross-validated buoy heat flux time series are then used to assess the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR), NCEP/Department of Energy, and 40-year European Centre for Medium-Range Weather Forecasts reanalyses' surface heat fluxes. All reanalyses show that over warm water where deep convection is prominent, latent heat loss is too large and net solar radiation is too weak; conversely, in regions of stratocumulus over cool water, net solar radiation is too strong, and for NCEP/NCAR, latent heat loss is too weak.

  19. Moisture Fluxes Derived from EOS Aqua Satellite Data for the North Water Polynya Over 2003-2009

    NASA Technical Reports Server (NTRS)

    Boisvert, Linette N.; Markus, Thorsten; Parkinson, Claire L.; Vihma, Timo

    2012-01-01

    Satellite data were applied to calculate the moisture flux from the North Water polynya during a series of events spanning 2003-2009. The fluxes were calculated using bulk aerodynamic formulas with the stability effects according to the Monin-Obukhov similarity theory. Input parameters were taken from three sources: air relative humidity, air temperature, and surface temperature from the Atmospheric Infrared Sounder (AIRS) onboard NASA's Earth Observing System (EOS) Aqua satellite, sea ice concentration from the Advanced Microwave Scanning Radiometer (AMSR-E, also onboard Aqua), and wind speed from the ECMWF ERA-Interim reanalysis. Our results show the progression of the moisture fluxes from the polynya during each event, as well as their atmospheric effects after the polynya has closed up. These results were compared to results from studies on other polynyas, and fall within one standard deviation of the moisture flux estimates from these studies. Although the estimated moisture fluxes over the entire study region from AIRS are smaller in magnitude than ERA-Interim, they are more accurate due to improved temperature and relative humidity profiles and ice concentration estimates over the polynya. Error estimates were calculated to be 5.56 x10(exp -3) g/sq. m/ s, only 25% of the total moisture flux, thus suggesting that AIRS and AMSR-E can be used with confidence to study smaller scale features in the Arctic sea ice pack and can capture their atmospheric effects. These findings bode well for larger-scale studies of moisture fluxes over the entire Arctic Ocean and the thinning ice pack.

  20. A surface radiation climatology across two Meteosat satellite generations

    NASA Astrophysics Data System (ADS)

    Posselt, Rebekka; Müller, Richard; Trentmann, Jörg; Stöckli, Reto; Liniger, Mark A.

    2013-04-01

    Long term observations of the surface radiation budget are essential for climate monitoring, for climate model evaluation and for applications such as in the solar energy or agriculture sector. The Satellite Application Facility on Climate Monitoring (CM SAF) released a Climate Data Record (CDR) of global and direct surface irradiance as well as effective cloud albedo derived from observations of the Meteosat First Generation satellites (MFG, 1983-2005). We will present an extension of this CDR using measurements from the Meteosat Second Generation satellites (MSG, 2004-present). The differences in the spectral properties of the radiometers aboard the MFG and MSG satellites requires a modification of the original MagicSol algorithm. In order to guarantee a climatologically homogeneous continuation of MFG-based CDR, the two narrowband visible channels of the MSG satellites are combined to simulate the MFG broadband visible channel. The combination of the MFG and MSG based datasets is tested for homogeneity and no significant breaks are detected during the overlap period of 2004-2005. Validation of the extended global radiation dataset against ground based observations from the Baseline Surface Radiation Network yields a mean monthly absolute bias of 8.15 Wm-2. This complies to the target accuracy threshold of 15 Wm-2 (including a measurement uncertainty of the surface observations of 5 Wm-2) required for satellite-derived CDR's of global radiation by the Global Climate Observing System. Climatological analysis of the extended surface radiation dataset shows an overall positive trend of the global radiation for the Meteosat disc (with variable extents and significances for different regions) which can be attributed to a negative trend in the effective cloud albedo, i.e., a decrease in cloudiness. Trends due to changes in the clear sky radiation are small and only induced by trends in the water vapour fields. Trends caused by changes in the direct effects of

  1. Open ocean gas transfer velocity derived from long-term direct measurements of the CO2 flux

    NASA Astrophysics Data System (ADS)

    Prytherch, John; Yelland, Margaret J.; Pascal, Robin W.; Moat, Bengamin I.; Skjelvan, Ingunn; Srokosz, Meric A.

    2010-12-01

    Air-sea open ocean CO2 flux measurements have been made using the Eddy Covariance (EC) technique onboard the weathership Polarfront in the North Atlantic between September 2006 and December 2009. Flux measurements were made using an autonomous system ‘AutoFlux’. CO2 mass density was measured with an open-path infrared gas analyzer. Following quality control procedures, 3938 20-minute flux measurements were made at mean wind speeds up to 19.6 m/s, significantly higher wind speeds than previously published results. The uncertainty in the determination of gas transfer velocities is large, but the mean relationship to wind speed allows a new parameterisation of the gas transfer velocity to be determined. A cubic dependence of gas transfer on wind speed is found, suggesting a significant influence of bubble-mediated exchange on gas transfer.

  2. An EOF Iteration Approach for Obtaining Homogeneous Radiative Fluxes from Satellites Observations

    NASA Technical Reports Server (NTRS)

    Zhang, Banglin; Pinker, Rachel T.; Stackhouse, Paul W., Jr.

    2007-01-01

    Conventional observations of climate parameters are sparse in space and/or in time and the representativeness of such information needs to be optimized. Observations from satellites provide improved spatial coverage than point observations however they pose new challenges for obtaining homogeneous coverage. Surface radiative fluxes, the forcing functions of the hydrologic cycle and biogeophysical processes, are now becoming available from global scale satellite observations. They are derived from independent satellite platforms and sensors that differ in temporal and spatial resolution and in the size of the footprint from which information is derived. Data gaps, degraded spatial resolution near boundaries of geostationary satellites, and different viewing geometries in areas of satellite overlap, could result in biased estimates of radiative fluxes. In this study, discussed will be issues related to the sources of inhomogeneity in surface radiative fluxes as derived from satellites; development of an approach to obtain homogeneous data sets; and application of the methodology to the widely used International Satellite Cloud Climatology Project (ISCCP) data that currently serve as a source of information for deriving estimates of surface and top of the atmosphere radiative fluxes. Introduced is an Empirical Orthogonal Function (EOF) iteration scheme for homogenizing the fluxes. The scheme is evaluated in several ways including comparison of the inferred radiative fluxes against ground observations, both before and after the EOF approach is applied. On the average, the latter reduces the rms error by about 2-3 W/m2.

  3. Heat flux estimates over vegetation derived using radiometric surface temperatures and a boundary layer model in comparison with sodar-derived values. M.S. Thesis; [Rock Springs Agricultural Research Center, Pennsylvania

    NASA Technical Reports Server (NTRS)

    Cooper, J. N. (Principal Investigator)

    1981-01-01

    An attempt was made to validate a method that uses radiometric surface temperatures and a boundary layer model to estimate surface energy budgets and characteristics. Surface temperatures from a hand-held radiometer and sodar data were collected simultaneously on seven days between mid-July and mid-October 1980. The comparison of the RDMS and sodar heat fluxes proved disappointing. Free convection conditions, required to produce sodar-derived heat fluxes, were inhibited by a terrain-induced low level inversion. Only three out of seven cases produced meaningful sodar heat fluxes. Of those three cases, one had good agreement and the other two had sodar heat fluxes 15 to 45 w/sq m lower than the RDMS values. Since the RDMS method is relatively untested, it was impossible to conclusively determine its validity from the results. There was evidence that the true heat flux was not underestimated by the RDMS, so it could be concluded that the Bowen ratios over well-watered vegetation were likely to be quite small.

  4. Long-wave radiative forcing due to dust aerosols: observations and climatology comparisons

    NASA Astrophysics Data System (ADS)

    Gunn, L. N.; Collins, W.

    2012-12-01

    Dust aerosols have been identified by the Intergovernmental Panel for Climate Change as a major source of uncertainty in the radiative forcing of the climate system. Optically thick plumes of dust and pollutants originating from arid regions can be lifted into the middle troposphere and are often transported over synoptic length scales. These events can decrease the upwelling long-wave fluxes at the top of atmosphere (TOA), especially in the mid-infrared portion of the spectrum. Although the long-wave effects of dust are included in model simulations, it is difficult to validate these effects in the absence of satellite-derived global estimates. Using hyper-spectral measurements from NASA's AIRS instrument, we estimate long-wave radiative forcing due to dust over the oceans for the year 2007. Firstly, we will present the results of these global, year long, radiative forcing estimates and secondly, we will use these estimates, along with other variables available from A-train instruments (e.g. MODIS aerosol optical depth) to evaluate the long-wave radiative forcing values from climatological data.

  5. Comparative Climatology of Terrestrial Planets

    NASA Astrophysics Data System (ADS)

    Mackwell, Stephen J.; Simon-Miller, Amy A.; Harder, Jerald W.; Bullock, Mark A.

    stimulate further research on this critical subject. The study of climate involves much more than understanding atmospheric processes. This subtlety is particularly appreciated for Earth, where chemical cycles, geology, ocean influences, and biology are considered in most climate models. In Part IV, Surface and Interior, we look at the role that geochemical cycles, volcanism, and interior mantle processes play in the stability and evolution of terrestrial planetary climates. There is one vital commonality between the climates of all the planets of the solar system: Regardless of the different processes that dominate each of the climates of Earth, Mars, Venus, and Titan, they are all ultimately forced by radiation from the same star, albeit at variable distances. In Part V, Solar Influences, we discuss how the Sun's early evolution affected the climates of the terrestrial planets, and how it continues to control the temperatures and compositions of planetary atmospheres. This will be of particular interest as models of exoplanets, and the influences of much different stellar types and distances, are advanced by further observations. Comparisons of atmospheric and climate processes between the planets in our solar system has been a focus of numerous conferences over the past decade, including the Exoclimes conference series. In particular, this book project was closely tied to a conference on Comparative Climatology of Terrestrial Planets that was held in Boulder, Colorado, on June 25-28, 2012. This book benefited from the opportunity for the author teams to interact and obtain feedback from the broader community, but the chapters do not in general tie directly to presentations at the conference. The conference, which was organized by a diverse group of atmospheric and climate scientists led by Mark Bullock and Lori Glaze, sought to build connections between the various communities, focusing on synergies and complementary capabilities. Discussion panels at the end of most

  6. Comparative climatology of four marine stratocumulus regimes

    NASA Technical Reports Server (NTRS)

    Hanson, Howard P.

    1990-01-01

    The climatology of marine stratocumulus (MSc) cloud regimes off the west coasts of California, Peru, Morocco, and Angola are examined. Long-term, annual averages are presented for several quantities of interest in the four MSc regimes. The climatologies were constructed using the Comprehensive Ocean-Atmosphere Data Set (COADS). A 40 year time series of observations was extracted for 32 x 32 deg analysis domains. The data were taken from the monthly-averaged, 2 deg product. The resolution of the analysis is therefore limited to scales of greater than 200 km with submonthly variability not resolved. The averages of total cloud cover, sea surface temperature, and surface pressure are presented.

  7. A continuous measure of gross primary production for the conterminous United States derived from MODIS and AmeriFlux data

    SciTech Connect

    Xiao, Jingfeng; Zhuang, Qianlai; Law, Beverly E.; Chen, Jiquan; Baldocchi, D. D.; Ma, Siyan; Cook, David R.; Oren, Ram; Katul, G. G.; Gu, Lianhong

    2010-03-01

    The quantification of carbon fluxes between the terrestrial biosphere and the atmosphere is of scientific importance and also relevant to climate-policy making. Eddy covariance flux towers provide continuous measurements of ecosystem-level exchange of carbon dioxide spanning diurnal, synoptic, seasonal, and interannual time scales. However, these measurements only represent the fluxes at the scale of the tower footprint. Here we used remotely sensed data from the Moderate Resolution Imaging Spectroradiometer (MODIS) to upscale gross primary productivity (GPP) data from eddy covariance flux towers to the continental scale. We first combined GPP and MODIS data for 42 AmeriFlux towers encompassing a wide range of ecosystem and climate types to develop a predictive GPP model using a regression tree approach. The predictive model was trained using observed GPP over the period 2000 2004, and was validated using observed GPP over the period 2005 2006 and leave-one-out cross-validation. Our model predicted GPP fairly well at the site level. We then used the model to estimate GPP for each 1 km 1 km cell across the U.S. for each 8-day interval over the period from February 2000 to December 2006 using MODIS data. Our GPP estimates provide a spatially and temporally continuous measure of gross primary production for the U.S. that is a highly constrained by eddy covariance flux data. Our study demonstrated that our empirical approach is effective for upscaling eddy flux GPP data to the continental scale and producing continuous GPP estimates across multiple biomes. With these estimates, we then examined the patterns, magnitude, and interannual variability of GPP. We estimated a gross carbon uptake between 6.91 and 7.33 Pg C yr 1 for the conterminous U.S. Drought, fires, and hurricanes reduced annual GPP at regional scales and could have a significant impact on the U.S. net ecosystem carbon exchange. The sources of the interannual variability of U.S. GPP were dominated by these

  8. A solely radiance-based spectral angular distribution model and its application in deriving clear-sky spectral fluxes over tropical oceans

    NASA Astrophysics Data System (ADS)

    Song, Lei; Wang, Yinan

    2016-02-01

    The radiation budget at the top of the atmosphere plays a critical role in climate research. Compared to the broadband flux, the spectrally resolved outgoing longwave radiation or flux (OLR), with rich atmospheric information in different bands, has obvious advantages in the evaluation of GCMs. Unlike methods that need auxiliary measurements and information, here we take atmospheric infrared sounder (AIRS) observations as an example to build a self-consistent algorithm by an angular distribution model (ADM), based solely on radiance observations, to estimate clear-sky spectrally resolved fluxes over tropical oceans. As the key step for such an ADM, scene type estimations are obtained from radiance and brightness temperature in selected AIRS channels. Then, broadband OLR as well as synthetic spectral fluxes are derived by the spectral ADM and validated using both synthetic spectra and CERES (Clouds and the Earth's Radiant Energy System) observations. In most situations, the mean OLR differences between the spectral ADM products and the CERES observations are within ±2 W m-2, which is less than 1% of the typical mean clear-sky OLR over tropical oceans. The whole algorithm described in this study can be easily extended to other similar hyperspectral radiance measurements.

  9. Xylem transport of root-derived CO2: An alternative flux pathway of substantial importance for understanding the components of ecosystem respiration

    NASA Astrophysics Data System (ADS)

    Aubrey, D. P.; Teskey, R. O.

    2011-12-01

    Forest ecosystem respiration releases one of the largest annual CO2 fluxes of the global carbon cycle and is dominated by belowground autotrophic and heterotrophic contributions. A mechanistic understanding of forest respiratory flux pathways is imperative to understanding carbon cycling in forests. We recently demonstrated that, on a daily basis, the amount of CO2 that fluxes upward from tree root systems into stems via the xylem stream rivals the amount of CO2 diffusing from the soil surface. However, our original observations were limited to only four individual eastern cottonwood (Populus deltoides L.) trees over a single week where environmental conditions remained similar. Here, we expand our investigation to an entire growing season using nine trees. We calculated the internal transport of root-derived CO2 as the product of sap flow and dissolved CO2 concentration ([CO2]) in the xylem at the base of the stem and measured soil CO2 efflux using the [CO2] gradient approach. We then compared the magnitude of these two flux pathways throughout the growing season. The internal transport of root-derived CO2 was equivalent to one-third of the total belowground respiration throughout the growing season. This indicates that autotrophic respiration was substantially higher than previously estimated, and also higher than heterotrophic soil respiration. The quantity of internally transported CO2 was influenced by both seasonal and daily environmental factors that influenced sap flow rates. We observed high concentrations of CO2 in xylem sap which ranged from 1% to 20% [CO2] among and within individual trees through time. Our results provide evidence that belowground autotrophic respiration consumes a larger amount-and stem respiration consumes a smaller amount-of carbohydrates than previously realized. The magnitude of the internal pathway for root-derived CO2 flux highlights the inadequacy of using the CO2 efflux from the soil surface to the atmosphere alone to measure

  10. A 30 year High -Spatial Resolution Cloud Climatology from NOAA's PATMOS-x Project

    NASA Astrophysics Data System (ADS)

    Heidinger, A. K.; Walther, A.; Foster, M. J.

    2010-12-01

    The Pathfinder Atmospheres Extended (PATMOS-x) project at NOAA has recently developed a new higher spatial resolution data set derived from over 30 years of data from the Advanced Very High Resolution Radiometer. The PATMOS-x data is now online and has been submitted into the GEWEX cloud climatology assessment library of cloud climate data sets. This data also benefits from a recent recalibration of the solar reflectance channels. This work will present our latest analysis and provide our insights into the strengths and limitations of this new data. Comparisons with GEWEX data sets and to the recently generated AVHRR cloud climatology from EUMETSAT will be shown.

  11. Towards a Wind Energy Climatology at Advanced Turbine Hub-Heights: Preprint

    SciTech Connect

    Schwartz, M.; Elliott, D.

    2005-05-01

    Measurements of wind characteristics over a wide range of heights up to and above 100 m are useful to: (1) characterize the local and regional wind climate; (2) validate wind resource estimates derived from numerical models; and (3) evaluate changes in wind characteristics and wind shear over the area swept by the blades. Developing wind climatology at advanced turbine hub heights for the United States benefits wind energy development. Tall tower data from Kansas, Indiana, and Minnesota (which have the greatest number of tall towers with measurement data) will be the focus of this paper. Analyses of data from the tall towers will start the process of developing a comprehensive climatology.

  12. Aircraft trace gas measurements during the London 2012 Olympics: Air quality and emission fluxes derived from sampling upwind and downwind of a megacity

    NASA Astrophysics Data System (ADS)

    Allen, G.; O'Shea, S.; Muller, J.; Jones, B.; O'Sullivan, D.; Lee, J. D.; Bauguitte, S.; Gallagher, M. W.; Percival, C.; Barratt, B.; McQuaid, J. B.; Illingworth, S.

    2013-12-01

    This study presents airborne in situ and remote sensing measurements recorded during July and August 2012, across the period of the London 2012 Summer Olympics and simultaneous with the Clear air for London (ClearfLo) ground-based measurement and modelling campaign. Through long-term (2-year) and intensive observation periods (Winter 2011 and Summer 2012), the ClearfLo programme aims to better understand emissions, as well as the chemical, dynamical and micro-meteorological processes which modulate air quality in the London urban environment - an important risk factor for both acute and chronic health effects. The work presented here focuses on two contrasting case studies within the summer ClearfLo period: 30 July 2012 and 9 August 2012, representing relatively clean background and polluted background cases, respectively, and characterised by well-mixed Atlantic westerly maritime inflow in the former and stagnant air (high pressure) in the latter. Measurements of CO, CO2, CH4, N2O, O3, HCN, and other gases measured on board the UK Facility for Airborne Atmospheric Measurement (FAAM) BAe-146 aircraft will be presented and interpreted, with emphasis on observed concentration gradients and tracer-tracer correlations as well as airmass vertical structure and airmass history upwind and downwind of central London in each case. By applying a simple advective model and making use of vertically resolved thermodynamic and composition data, we are able to derive emission strengths for these gases that are representative of the total enclosed surface area. Example emissions for these two cases range between 6x105 kg(C)/hr and 9x105 kg(C)/hr for CO2, and ~0.6x105 kg(C)/hr for CH4. This airborne sampling methodology highlights the unique utility of aircraft measurements to routinely and climatologically characterise emissions from area sources such as cities, and points to future missions to target localised hotspots and distributed point sources.

  13. Assessing the Potential to Derive Air-Sea Freshwater Fluxes from Aquarius-Like Observations of Surface Salinity

    NASA Technical Reports Server (NTRS)

    Zhen, Li; Adamec, David

    2009-01-01

    A state-of-the-art numerical model is used to investigate the possibility of determining freshwater flux fields from temporal changes io sea-surface salinity (SSS), a goal of the satellite salinity-measuring mission, Aquarius/SAC-D. Because the estimated advective temporal scale is usually longer than the Aquarius/SAC-D revisit time, the possibility of producing freshwater flux estimates from temporal salinity changes is first examined by using a correlation analysis. For the mean seasonal cycle, the patterns of the correlations between the freshwater fluxes and surface salinity temporal tendencies are mainly zonally oriented, and are highest where the local precipitation is also relatively high. Nonseasonal (deviations from the monthly mean) correlations are highest along mid-latitude moon tracks and are relatively small in the tropics. The complex correlation patterns presented here suggest that a global retrieval of the difference between evaporation and precipitation (E-P) from salinity changes requires more complex techniques than a simple consideration of local balance with surface forcing.

  14. On the climatological probability of the vertical propagation of stationary planetary waves

    NASA Astrophysics Data System (ADS)

    Karami, K.; Braesicke, P.; Sinnhuber, M.; Versick, S.

    2015-11-01

    We introduce a diagnostic tool to assess in a climatological framework the optimal propagation conditions for stationary planetary waves. Analyzing 50 winters using NCEP/NCAR reanalysis data we derive probability density functions (PDFs) of positive refractive indices as a function of zonal and meridional wave numbers. We contrast this quantity with classical climatological means of the refractive index. Introducing a Membership Value Function (MVF) based on fuzzy logic, we objectively generate a modified set of PDFs (mPDFs) and demonstrate their superior performance compared to the climatological mean of refractive indices and the original PDFs. We argue that mPDFs allow an even better understanding of how background conditions impact wave propagation in a climatological sense. As expected, probabilities are decreasing with increasing zonal wave numbers. In addition we discuss the meridional wave number dependency of the PDFs which is usually neglected, highlighting the contribution of meridional wave numbers 2 and 3 in the stratosphere. We also describe how mPDFs change in response to strong vortex regime (SVR) and weak vortex regime (WVR) conditions, with increased probabilities during WVR than SVR in the stratosphere. We conclude that the mPDFs are a convenient way to summarize climatological information about planetary wave propagation in reanalysis and climate model data.

  15. On the climatological probability of the vertical propagation of stationary planetary waves

    NASA Astrophysics Data System (ADS)

    Karami, Khalil; Braesicke, Peter; Sinnhuber, Miriam; Versick, Stefan

    2016-07-01

    We introduce a diagnostic tool to assess a climatological framework of the optimal propagation conditions for stationary planetary waves. Analyzing 50 winters using NCEP/NCAR (National Center for Environmental Prediction/National Center for Atmospheric Research) reanalysis data we derive probability density functions (PDFs) of positive vertical wave number as a function of zonal and meridional wave numbers. We contrast this quantity with classical climatological means of the vertical wave number. Introducing a membership value function (MVF) based on fuzzy logic, we objectively generate a modified set of PDFs (mPDFs) and demonstrate their superior performance compared to the climatological mean of vertical wave number and the original PDFs. We argue that mPDFs allow an even better understanding of how background conditions impact wave propagation in a climatological sense. As expected, probabilities are decreasing with increasing zonal wave numbers. In addition we discuss the meridional wave number dependency of the PDFs which is usually neglected, highlighting the contribution of meridional wave numbers 2 and 3 in the stratosphere. We also describe how mPDFs change in response to strong vortex regime (SVR) and weak vortex regime (WVR) conditions, with increased probabilities of the wave propagation during WVR than SVR in the stratosphere. We conclude that the mPDFs are a convenient way to summarize climatological information about planetary wave propagation in reanalysis and climate model data.

  16. A 19-Month Climatology of Marine Aerosol-Cloud-Radiation Properties Derived From DOE ARM AMF Deployment at the Azores: Part I: Cloud Fraction and Single-Layered MBL Cloud Properties

    NASA Technical Reports Server (NTRS)

    Dong, Xiquan; Xi, Baike; Kennedy, Aaron; Minnis, Patrick; Wood, Robert

    2013-01-01

    A 19-month record of total, and single-layered low (0-3 km), middle (3-6 km), and high (> 6 km) cloud fractions (CFs), and the single-layered marine boundary layer (MBL) cloud macrophysical and microphysical properties has been generated from ground-based measurements taken at the ARM Azores site between June 2009 and December 2010. It documents the most comprehensive and longest dataset on marine cloud fraction and MBL cloud properties to date. The annual means of total CF, and single-layered low, middle, and high CFs derived from ARM radar-lidar observations are 0.702, 0.271, 0.01 and 0.106, respectively. More total and single-layered high CFs occurred during winter, while single-layered low CFs were greatest during summer. The diurnal cycles for both total and low CFs are stronger during summer than during winter. The CFs are bimodally distributed in the vertical with a lower peak at approx. 1 km and higher one between 8 and 11 km during all seasons, except summer, when only the low peak occurs. The persistent high pressure and dry conditions produce more single-layered MBL clouds and fewer total clouds during summer, while the low pressure and moist air masses during winter generate more total and multilayered-clouds, and deep frontal clouds associated with midlatitude cyclones.

  17. Passive acoustic derived bubble flux and applications to natural gas seepage in the Mackenzie Delta, NWT, Canada and Coal Oil Point, CA

    NASA Astrophysics Data System (ADS)

    Culling, D.; Leifer, I.; Dallimore, S.; Alcala, K.

    2012-12-01

    Minnaert equation predicts. Furthermore, bubbles from a cohesive media escaped in pulses of multiple bubbles, which caused significant inter-bubble acoustic coupling and mud-bubble interaction. The acoustic signature of subsurface bubble migration and concurrent sediment movements, including bubble pinch off, presented additional complexities. Use of passive acoustic derived flux was applied to natural gas seepage in the Mackenzie Delta in the North West Territories, Canada as well as offshore Coal Oil Point (COP), CA. Video data were used to calibrate the COP acoustic observations and showed a strong current impact for non-cohesive sediments. Seepage flux in the delta (cohesive sediments) was calibrated using a custom turbine tent that directly measured flux. Further applications of passive acoustic-derived seep fluxes include monitoring of marine pipelines for leaks, and studying biogenic wetlands ebullition as well as thermogenic and hydrate seepage.

  18. Development and Testing of the New Surface LER Climatology for OMI UV Aerosol Retrievals

    NASA Technical Reports Server (NTRS)

    Gupta, Pawan; Torres, Omar; Jethva, Hiren; Ahn, Changwoo

    2014-01-01

    Ozone Monitoring Instrument (OMI) onboard Aura satellite retrieved aerosols properties using UV part of solar spectrum. The OMI near UV aerosol algorithm (OMAERUV) is a global inversion scheme which retrieves aerosol properties both over ocean and land. The current version of the algorithm makes use of TOMS derived Lambertian Equivalent Reflectance (LER) climatology. A new monthly climatology of surface LER at 354 and 388 nm have been developed. This will replace TOMS LER (380 nm and 354nm) climatology in OMI near UV aerosol retrieval algorithm. The main objectives of this study is to produce high resolution (quarter degree) surface LER sets as compared to existing one degree TOMS surface LERs, to product instrument and wavelength consistent surface climatology. Nine years of OMI observations have been used to derive monthly climatology of surface LER. MODIS derived aerosol optical depth (AOD) have been used to make aerosol corrections on OMI wavelengths. MODIS derived BRDF adjusted reflectance product has been also used to capture seasonal changes in the surface characteristics. Finally spatial and temporal averaging techniques have been used to fill the gaps around the globes, especially in the regions with consistent cloud cover such as Amazon. After implementation of new surface data in the research version of algorithm, comparisons of AOD and single scattering albedo (SSA) have been performed over global AERONET sites for year 2007. Preliminary results shows improvements in AOD retrievals globally but more significance improvement were observed over desert and bright locations. We will present methodology of deriving surface data sets and will discuss the observed changes in retrieved aerosol properties with respect to reference AERONET measurements.

  19. A 15-year Climatology of Deep Stratosphere-troposphere Exchange With A Lagrangian Particle Dispersion Model

    NASA Astrophysics Data System (ADS)

    James, P.; Stohl, A.; Forster, C.; Eckhardt, S.

    Stratosphere-Troposphere Exchange (STE) is a key element of the global atmospheric circulation, impacting on mean atmospheric chemistry budgets in both stratosphere and troposphere. A comprehensive study of deep STE, based on ECMWF global at- mospheric re-analysis data, has been carried out for the EU-project STACCATO with the Lagrangian particle dispersion model FLEXPART. The model was initialised with half a million particles, distributed randomly throughout the atmosphere, and inte- grated continually for 15 years, providing the basis for a climatology of STE, showing its typical timescales, seasonality, and spatial and interannual variability. A major ad- vantage of FLEXPART is enabling one to distinguish between short-term STE, during which air parcels rapidly return to the stratosphere, and deep and/or long-term STE, in which air parcels have subsequently long residence times in the troposphere, thus having a greater impact on atmospheric chemistry. STE distributions relate closely to global circulation features. Stratospheric intrusions occur most frequently in the mid- latitude storm track regions. Much of this air returns to the stratosphere within synop- tic timescales. The more deeply intruded air which remains is subsequently imbedded into the large-scale meridional circulation, resulting in the greatest proportion of old stratospheric air in the tropics and the polar boundary layer, as revealed by age spec- tra. Circulation anomalies (eg. NAO) influence the tropospheric distribution of young stratospheric air in particular. Concentrations of stratospheric air in the troposphere show a distinct winter maximum for deep STE intrusions, especially for cases of rapid descent. The often quoted 'spring maximum' of STE, typically derived by just fo- cussing on cross-tropopause fluxes, applies only in the upper troposphere and thus to shallow STE events alone. Cross-tropopause mass flux is shown to be an inadequate measure for many aspects of STE.

  20. The effect of assimilating satellite-derived soil moisture data in SiBCASA on simulated carbon fluxes in Boreal Eurasia

    NASA Astrophysics Data System (ADS)

    van der Molen, M. K.; de Jeu, R. A. M.; Wagner, W.; van der Velde, I. R.; Kolari, P.; Kurbatova, J.; Varlagin, A.; Maximov, T. C.; Kononov, A. V.; Ohta, T.; Kotani, A.; Krol, M. C.; Peters, W.

    2016-02-01

    Boreal Eurasia is a region where the interaction between droughts and the carbon cycle may have significant impacts on the global carbon cycle. Yet the region is extremely data sparse with respect to meteorology, soil moisture, and carbon fluxes as compared to e.g. Europe. To better constrain our vegetation model SiBCASA, we increase data usage by assimilating two streams of satellite-derived soil moisture. We study whether the assimilation improved SiBCASA's soil moisture and its effect on the simulated carbon fluxes. By comparing to unique in situ soil moisture observations, we show that the passive microwave soil moisture product did not improve the soil moisture simulated by SiBCASA, but the active data seem promising in some aspects. The match between SiBCASA and ASCAT soil moisture is best in the summer months over low vegetation. Nevertheless, ASCAT failed to detect the major droughts occurring between 2007 and 2013. The performance of ASCAT soil moisture seems to be particularly sensitive to ponding, rather than to biomass. The effect on the simulated carbon fluxes is large, 5-10 % on annual GPP and TER, tens of percent on local NEE, and 2 % on area-integrated NEE, which is the same order of magnitude as the inter-annual variations. Consequently, this study shows that assimilation of satellite-derived soil moisture has potentially large impacts, while at the same time further research is needed to understand under which conditions the satellite-derived soil moisture improves the simulated soil moisture.

  1. The Savannah River Technology Center Research and Development Climatology Center

    SciTech Connect

    Kurzeja, R.J.

    1995-12-31

    The Environmental Technology Section (ETS) of the Savannah River Technology Center (SRTC) built and has operated the Climatology Site (CS) for almost 10 years. The Climatology Site provides a wide variety of meteorological support functions for Savannah River Site (SRS) operations and research. This document describes the Climatology Site facility to familiarize present and potential users with its capabilities.

  2. Climatology of extratropical transition for North Atlantic tropical cyclones in the high-resolution GFDL climate model

    NASA Astrophysics Data System (ADS)

    Liu, M.; Vecchi, G. A.; Smith, J. A.

    2015-12-01

    The extratropical transition (ET) process of tropical cyclones can lead to fundamental changes in hurricane structure and storms that continue to pose large threats to life and properties. Given the importance of ET, it is necessary to understand how ET changes under a warming climate. Towards this goal, the GFDL climate model (FLOR) is first used to understand the current-day ET climatology. The standard model and a flux-adjusted version of FLOR are both used to examine ET climatology. The operational cyclone phase space method is used to define the onset and completion times of ET. The ET climatology from the climate model is compared with those from two reanalysis data sets ranging from 1979 to 2012. Both models exhibit good skills at simulating the frequency map of phase space diagram. The flux-adjusted version shows much better skill in capturing the ET climatology in terms of ET track patterns, ET locations and monthly ET variations. The model is able to simulate the frequency ratio of reintensified tropical cyclones from all ET cases. Future work involves examining changes in the ET climatology under a changing climate.

  3. The uncertainty of UTCI due to uncertainties in the determination of radiation fluxes derived from measured and observed meteorological data

    NASA Astrophysics Data System (ADS)

    Weihs, Philipp; Staiger, Henning; Tinz, Birger; Batchvarova, Ekaterina; Rieder, Harald; Vuilleumier, Laurent; Maturilli, Marion; Jendritzky, Gerd

    2012-05-01

    In the present study, we investigate the determination accuracy of the Universal Thermal Climate Index (UTCI). We study especially the UTCI uncertainties due to uncertainties in radiation fluxes, whose impacts on UTCI are evaluated via the mean radiant temperature ( Tmrt). We assume "normal conditions", which means that usual meteorological information and data are available but no special additional measurements. First, the uncertainty arising only from the measurement uncertainties of the meteorological data is determined. Here, simulations show that uncertainties between 0.4 and 2 K due to the uncertainty of just one of the meteorological input parameters may be expected. We then analyse the determination accuracy when not all radiation data are available and modelling of the missing data is required. Since radiative transfer models require a lot of information that is usually not available, we concentrate only on the determination accuracy achievable with empirical models. The simulations show that uncertainties in the calculation of the diffuse irradiance may lead to Tmrt uncertainties of up to ±2.9 K. If long-wave radiation is missing, we may expect an uncertainty of ±2 K. If modelling of diffuse radiation and of longwave radiation is used for the calculation of Tmrt, we may then expect a determination uncertainty of ±3 K. If all radiative fluxes are modelled based on synoptic observation, the uncertainty in Tmrt is ±5.9 K. Because Tmrt is only one of the four input data required in the calculation of UTCI, the uncertainty in UTCI due to the uncertainty in radiation fluxes is less than ±2 K. The UTCI uncertainties due to uncertainties of the four meteorological input values are not larger than the 6 K reference intervals of the UTCI scale, which means that UTCI may only be wrong by one UTCI scale. This uncertainty may, however, be critical at the two temperature extremes, i.e. under extreme hot or extreme cold conditions.

  4. A Statistical Aggregation Engine for Climatology and Trend Analysis

    NASA Astrophysics Data System (ADS)

    Chapman, D. R.; Simon, T. A.; Halem, M.

    2014-12-01

    Fundamental climate data records (FCDRs) from satellite instruments often span tens to hundreds of terabytes or even petabytes in scale. These large volumes make it difficult to aggregate or summarize their climatology and climate trends. It is especially cumbersome to supply the full derivation (provenance) of these aggregate calculations. We present a lightweight and resilient software platform, Gridderama that simplifies the calculation of climatology by exploiting the "Data-Cube" topology often present in earth observing satellite records. By using the large array storage (LAS) paradigm, Gridderama allows the analyst to more easily produce a series of aggregate climate data products at progressively coarser spatial and temporal resolutions. Furthermore, provenance tracking and extensive visualization capabilities allow the analyst to track down and correct for data problems such as missing data and outliers that may impact the scientific results. We have developed and applied Gridderama to calculate a trend analysis of 55 Terabytes of AIRS Level 1b infrared radiances, and show statistically significant trending in the greenhouse gas absorption bands as observed by AIRS over the 2003-2012 decade. We will extend this calculation to show regional changes in CO2 concentration from AIRS over the 2003-2012 decade by using a neural network retrieval algorithm.

  5. Tracer Lamination in the Stratosphere: A Global Climatology

    NASA Technical Reports Server (NTRS)

    Appenzeller, Christof; Holton, James R.

    1997-01-01

    Vertical soundings of stratospheric ozone often exhibit laminated tracer structures characterized by strong vertical tracer gradients. The change in time of these gradients is used to define a tracer lamination rate. It is shown that this quantity can be calculated by the cross product of the horizontal temperature and horizontal tracer gradients. A climatology based on UARS satellite-borne ozone data and on ozone-like pseudotracer data is presented. Three stratospheric regions with high lamination rates were found: the part of the stratospheric overworld which is influenced by the polar vortex, the part of the lowermost stratosphere which is influenced by the tropopause and a third region in the subtropical lower stratosphere mainly characterized with strong vertical shear. High lamination rates in the stratospheric overworld were absent during summer, whereas in the lowermost stratosphere high lamination rates were found year-round. This is consistent with the occurrence and seasonal variation of the horizontal tracer gradient and vertical shear necessary for tilting the tracer surfaces. During winter, high lamination rates associated with the stratospheric polar vortex are present down to approximately 100 hPa. Several features of the derived climatology are roughly consistent with earlier balloon-borne studies. The patterns in the southern and northern hemisphere are comparable, but details differ as anticipated from a less disturbed and more symmetric southern polar vortex.

  6. A climatological link between slantwise instability and surface weather conditions

    NASA Astrophysics Data System (ADS)

    Glinton, M. R.; Gray, S. L.; Chagnon, J. M.; Morcrette, C. J.

    2012-04-01

    Midlatitude weather phenomena including rainbands in fronts and cloud heads and the descending sting jets found in extreme windstorms have been attributed, in part, to the release of conditional symmetric instability (CSI). CSI is a slantwise parcel instability arising from the combination of inertial and gravitational instability in a baroclinic atmosphere; its release gives slantwise convection. However, to date, demonstration of the link between CSI and severe weather has been confined to a few case studies. Weather forecast models with domains big enough to encompass entire midlatitude storms do not have sufficient resolution to realistically resolve the release of CSI, and CSI release is not parameterized in these models. The consequences of this lack of representation of CSI release are currently unknown and motivate this study. We present a North Atlantic climatology of the energy available for slantwise convection due to CSI derived from the ERA-Interim re-analysis, and compare it with an equivalent climatology of CAPE (the energy available for upright convection due to conditional instability). The annual cycle of land and sea surface temperatures are shown to strongly modulate these instabilities. The statistical relationship between these instabilities and surface weather conditions are presented.

  7. A semianalytical algorithm for quantitatively estimating sediment and atmospheric deposition flux from MODIS-derived sea ice albedo in the Bohai Sea, China

    NASA Astrophysics Data System (ADS)

    Xu, Zhantang; Hu, Shuibo; Wang, Guifen; Zhao, Jun; Yang, Yuezhong; Cao, Wenxi; Lu, Peng

    2016-05-01

    Quantitative estimates of particulate matter [PM) concentration in sea ice using remote sensing data is helpful for studies of sediment transport and atmospheric dust deposition flux. In this study, the difference between the measured dirty and estimated clean albedo of sea ice was calculated and a relationship between the albedo difference and PM concentration was found using field and laboratory measurements. A semianalytical algorithm for estimating PM concentration in sea ice was established. The algorithm was then applied to MODIS data over the Bohai Sea, China. Comparisons between MODIS derived and in situ measured PM concentration showed good agreement, with a mean absolute percentage difference of 31.2%. From 2005 to 2010, the MODIS-derived annual average PM concentration was approximately 0.025 g/L at the beginning of January. After a month of atmospheric dust deposition, it increased to 0.038 g/L. Atmospheric dust deposition flux was estimated to be 2.50 t/km2/month, similar to 2.20 t/km2/month reported in a previous study. The result was compared with on-site measurements at a nearby ground station. The ground station was close to industrial and residential areas, where larger dust depositions occurred than in the sea, but although there were discrepancies between the absolute magnitudes of the two data sets, they demonstrated similar trends.

  8. Fluxes of Reserve-Derived and Currently Assimilated Carbon and Nitrogen in Perennial Ryegrass Recovering from Defoliation. The Regrowing Tiller and Its Component Functionally Distinct Zones1

    PubMed Central

    Schnyder, Hans; de Visser, Ries

    1999-01-01

    The quantitative significance of reserves and current assimilates in regrowing tillers of severely defoliated plants of perennial ryegrass (Lolium perenne L.) was assessed by a new approach, comprising 13C/12C and 15N/14N steady-state labeling and separation of sink and source zones. The functionally distinct zones showed large differences in the kinetics of currently assimilated C and N. These are interpreted in terms of ”substrate” and ”tissue” flux among zones and C and N turnover within zones. Tillers refoliated rapidly, although C and N supply was initially decreased. Rapid refoliation was associated with (a) transient depletion of water-soluble carbohydrates and dilution of structural biomass in the immature zone of expanding leaves, (b) rapid transition to current assimilation-derived growth, and (c) rapid reestablishment of a balanced C:N ratio in growth substrate. This balance (C:N, approximately 8.9 [w/w] in new biomass) indicated coregulation of growth by C and N supply and resulted from complementary fluxes of reserve- and current assimilation-derived C and N. Reserves were the dominant N source until approximately 3 d after defoliation. Amino-C constituted approximately 60% of the net influx of reserve C during the first 2 d. Carbohydrate reserves were an insignificant source of C for tiller growth after d 1. We discuss the physiological mechanisms contributing to defoliation tolerance. PMID:10198102

  9. Formation of the world's largest REE deposit through protracted fluxing of carbonatite by subduction-derived fluids

    PubMed Central

    Ling, Ming-Xing; Liu, Yu-Long; Williams, Ian S.; Teng, Fang-Zhen; Yang, Xiao-Yong; Ding, Xing; Wei, Gang-Jian; Xie, Lu-Hua; Deng, Wen-Feng; Sun, Wei-Dong

    2013-01-01

    Rare Earth Elements (REE) are essential to modern society but the origins of many large REE deposits remain unclear. The U-Th-Pb ages, chemical compositions and C, O and Mg isotopic compositions of Bayan Obo, the world's largest REE deposit, indicate a protracted mineralisation history with unusual chemical and isotopic features. Coexisting calcite and dolomite are in O isotope disequilibrium; some calcitic carbonatite samples show highly varied δ26Mg which increases with increasing Si and Mg; and ankerite crystals show decreases in Fe and REE from rim to centre, with highly varied REE patterns. These and many other observations are consistent with an unusual mineralisation process not previously considered; protracted fluxing of calcitic carbonatite by subduction-released high-Si fluids during the closure of the Palaeo-Asian Ocean. The fluids leached Fe and Mg from the mantle wedge and scavenged REE, Nb and Th from carbonatite, forming the deposit through metasomatism of overlying sedimentary carbonate.

  10. Anti-Atlas Moroccan Chain as the source of lithogenic-derived micronutrient fluxes to the deep Northeast Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Chavagnac, V.; Waniek, J. J.; Atkin, D.; Milton, J. A.; Leipe, T.; Green, D. R. H.; Bahlo, R.; Hayes, T. E. F.; Schulz-Bull, D. E.

    2007-11-01

    Identifying the source of atmospheric dust is crucial to better understand the global marine biogeochemical cycle as phytoplankton growth relies on dissolved micronutrient elements available in the open ocean. Mineralogical, geochemical and Sr isotope analyses of a one year-time series (April 2003-April 2004) of deep ocean particle flux at the Madeira Abyssal Plain in the subtropical northeast Atlantic are presented. The lithogenic fraction has a high occurrence of palygorskite and smectite and an absence of kaolinite together with Sr isotopic compositions similar to the Northeast Atlantic aerosols. This indicates the Anti-Atlas Moroccan chain of Paleozoïc age as the source region. The lithogenic fraction supplies 4 times more Fe during a dust event than during the spring-summer aeolian input. A continuous input of only 1% of the lithogenic iron made available over a year period, could lead to an increase in primary productivity of 40% relative to today's value.

  11. A new evaporation duct climatology over the South China Sea

    NASA Astrophysics Data System (ADS)

    Shi, Yang; Yang, Kunde; Yang, Yixin; Ma, Yuanliang

    2015-10-01

    The climatology of evaporation ducts is important for shipborne electromagnetic system design and application. The evaporation duct climatology that is currently used for such applications was developed in the mid 1980s; this study presents efforts to improve it over the South China Sea (SCS) by using a state-of-the-art evaporation duct model and an improved meteorology dataset. This new climatology provides better evaporation duct height (EDH) data over the SCS, at a higher resolution of 0.312°×0.313°. A comparison between the new climatology and the old one is performed. The monthly average EDH in the new climatology is between 10 and 12 m over the SCS, higher than that in the old climatology. The spatiotemporal characteristics of the evaporation duct over the SCS in different months are analyzed in detail, based on the new climatology.

  12. A tornado climatology for Ireland

    NASA Astrophysics Data System (ADS)

    Tyrrell, John

    The results of detailed records and site investigations of reported tornadoes, waterspouts and funnel clouds over the last 3 years (1999-2001) are presented. Part of the analysis also includes the more fragmented record from 1950. These results are placed in the context of the potential for the atmosphere to produce the type of severe convective weather over Ireland often associated with tornadoes. This has been characterised from an analysis of daily values of several extreme weather parameters, namely Convective Available Potential Energy (CAPE), Bulk Richardson Number (BRN) and Severe Weather (SWEAT), derived from upper air soundings at Valentia. It is concluded that this potential is slight, though sufficient to produce moderately intense tornadoes at times. The analysis of the tornado record demonstrates that the annual frequency of such severe events is highly variable. Nevertheless, there have been many as 30 per year, although the average frequency of 10 per year may be more typical. In contrast to neighbouring countries, tornadoes mostly occurred during the summer months, especially August. It suggested that the strong monthly and diurnal patterns in the data might have more complex explanations than appears at first sight, when the particular climatic circumstances of Ireland are taken into account. Tornado intensities have ranged between T0 and T6 (F0 and F3) and a relationship between tornado intensity, track length and track width is considered. Finally, the geographical distribution of tornado and funnel cloud events is presented and an interpretation is given that considers the possible role of the terrain and land surface conditions in the development of atmospheric environments conducive for tornado events in Ireland.

  13. Derivation of the photometric flux of daylight from filtered measurements of global (sun and sky) radiant energy.

    PubMed

    Drummond, A J; Angström, A K

    1971-09-01

    The study reported on here is a continuation of an earlier investigation by the same authors into the relationship between natural illumination and shortwave solar radiation. Whereas the initial approach treated the illumination of sunlight as derived from the corresponding filtered direct radiation component, the results now given extend this work to parallel determination of the (more generally applicable) illumination of integral daylight on the basis of similarly filtered global (sun and sky) radiation. Characteristics are outlined of the instrumentation employed in the investigation undertaken at different locations, viz., Newport, Jerusalem (Israel), and Mauna Loa (Hawaii), as compared with the basic work that utilized data assembled at Pretoria (South Africa). Included is an extension to recent solar radiation measurements obtained on high-altitude aircraft. In general, it is established that it is possible to derive such estimates of natural illumination from radiometric measurements with an accuracy comparable with that obtainable in the best direct photometric efforts. PMID:20111265

  14. Climatological data summary 1994, with historical data

    SciTech Connect

    Hoitink, D.J.; Burk, K.W.

    1995-05-01

    This document presents the climatological data measured at the U.S. Department of Energy`s Hanford Site for calendar year 1994. Pacific Northwest Laboratory operates the Hanford Meteorology Station and the Hanford Meteorological Monitoring Network from which these data were collected. The information contained herein includes updated historical climatologies for temperature, precipitation, normal and extreme values of temperature and precipitation, and other miscellaneous meteorological parameters. Further, the data are adjunct to and update Hoitink et al. (1994); however, Appendix B-Wind Climatology is excluded. 1994 was the second warmest year on record, averaging 56.2{degrees}F, 2.9{degrees}F above normal (53.3{degrees}F). For the 12-month period, 10 were warmer than normal (7 were at least 3.5{degrees}F and 2 were more than 5.0{degrees}F above normal). Precipitation totaled 6.12 in., 98% of normal (6.26 in.); snowfall totaled 5.2 in., compared to the normal of 13.8 in. The average wind speed during 1994 was 7.3 mph, 0.4 mph below normal (7.7 mph). The peak gust during the year was 52 mph from the south-southwest on February 13. There were 29 days with peak gusts {ge}40 mph, compared to a yearly average of 26.

  15. Cross-shelf and along-shelf fluxes derived from observation and modelling in the Gulf of Naples

    NASA Astrophysics Data System (ADS)

    Iermano, Ilaria; Falco, Pierpaolo; Zambianchi, Enrico

    2015-04-01

    Hydrological and currentmeter observations were collected on the continental shelf and slope of the Gulf of Naples during the GELATO experiment in the framework of med-TOSCA project (27 July to 6 August 2012). Results from the cruise are used to estimate the onshore/offshore cross-frontal transport at the shelf break of the Gulf of Naples. The hydrological structures evidence well-stratified water masses on the eastern and western ends of the shelf. In the coastal area the situation is quite complex, with the influence of the Sarno river's freshwater plume in the first meters of the water column. ADCP current profiles were used to estimate integrated transport along the meridional transect connecting the northern and southern gulf coast. ADCP data are missing in the surface layer because of the transducer ringing effect. To add the surface contribution to the total transport, HF radar current measurement were used to determine this component. CTD measurement were collected approximately along the same transect so both the barotropic and baroclinic contribution to the total transport can be evaluated. In addition, coastal circulation is simulated with a high resolution three-dimensional numerical model forced by daily realistic forcing along with heat and salt fluxes calculated by bulk formulae. The model outputs are in agreement with the main hydrological and circulation patterns and reproduces well the onshore transport.

  16. A novel tropopause-related climatology of ozone profiles

    NASA Astrophysics Data System (ADS)

    Sofieva, V. F.; Tamminen, J.; Kyrölä, E.; Mielonen, T.; Veefkind, P.; Hassler, B.; Bodeker, G. E.

    2013-08-01

    A new ozone climatology, based on ozonesonde and satellite measurements, spanning the altitude region between the Earth's surface and ~60 km is presented (TpO3 climatology). This climatology is novel in that the ozone profiles are categorized according to calendar month, latitude and local tropopause heights. Compared to the standard latitude-month categorization, this presentation improves the representativeness of the ozone climatology in the upper troposphere and the lower stratosphere (UTLS). The probability distribution of tropopause heights in each latitude-month bin provides additional climatological information and allows transforming/comparing the TpO3 climatology to a standard climatology of zonally mean ozone profiles. The TpO3 climatology is based on high-vertical-resolution measurements of ozone from the satellite-based Stratospheric Aerosol and Gas Experiment II (in 1984 to 2005) and from balloon-borne ozonesondes in 1980 to 2006. The main benefits of the TpO3 climatology are reduced standard deviations on climatological ozone profiles in the UTLS, partial characterization of longitudinal variability, and characterization of ozone profiles in the presence of double tropopauses. The first successful application of the TpO3 climatology as a priori in ozone profiles retrievals from Ozone Monitoring Instrument on board the EOS-Aura satellite shows an improvement of ozone precision in UTLS of up to 10% compared with the use of conventional climatologies. In addition to being advantageous for use as a priori in satellite retrieval algorithms, the TpO3 climatology might be also useful for validating the representation of ozone in climate model simulations.

  17. A novel tropopause-related climatology of ozone profiles

    NASA Astrophysics Data System (ADS)

    Sofieva, V. F.; Tamminen, J.; Kyrölä, E.; Mielonen, T.; Veefkind, P.; Hassler, B.; Bodeker, G. E.

    2014-01-01

    A new ozone climatology, based on ozonesonde and satellite measurements, spanning the altitude region between the earth's surface and ~60 km is presented (TpO3 climatology). This climatology is novel in that the ozone profiles are categorized according to calendar month, latitude and local tropopause heights. Compared to the standard latitude-month categorization, this presentation improves the representativeness of the ozone climatology in the upper troposphere and the lower stratosphere (UTLS). The probability distribution of tropopause heights in each latitude-month bin provides additional climatological information and allows transforming/comparing the TpO3 climatology to a standard climatology of zonal mean ozone profiles. The TpO3 climatology is based on high-vertical-resolution measurements of ozone from the satellite-based Stratospheric Aerosol and Gas Experiment II (in 1984 to 2005) and from balloon-borne ozonesondes from 1980 to 2006. The main benefits of the TpO3 climatology are reduced standard deviations on climatological ozone profiles in the UTLS, partial characterization of longitudinal variability, and characterization of ozone profiles in the presence of double tropopauses. The first successful application of the TpO3 climatology as a priori in ozone profile retrievals from Ozone Monitoring Instrument on board the Earth Observing System (EOS) Aura satellite shows an improvement of ozone precision in UTLS of up to 10% compared with the use of conventional climatologies. In addition to being advantageous for use as a priori in satellite retrieval algorithms, the TpO3 climatology might be also useful for validating the representation of ozone in climate model simulations.

  18. Radiative Flux Changes by Aerosols from North America, Europe, and Africa over the Atlantic Ocean: Measurements and Calculations from TARFOX and ACE-2

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Hignett, P.; Livingston, J. M.; Schmid, B.; Chien, A.; Bergstrom, R.; Durkee, P. A.; Hobbs, P. V.; Bates, T. S.; Quinn, P. K.; Condon, Estelle (Technical Monitor)

    1998-01-01

    Aerosol effects on atmospheric radiative fluxes provide a forcing function that is a major source of uncertainty in understanding the past climate and predicting climate change. To help reduce this uncertainty, the 1996 Tropospheric Aerosol Radiative Forcing Experiment (TARFOX) and the 1997 second Aerosol Characterization Experiment (ACE-2) measured the properties and radiative effects of American, European, and African aerosols over the Atlantic. In TARFOX, radiative fluxes and microphysics of the American aerosol were measured from the UK C-130 while optical depth spectra, aerosol composition, and other properties were measured by the University of Washington C-131A and the CIRPAS Pelican. Closure studies show that the measured flux changes agree with those derived from the aerosol measurements using several modelling approaches. The best-fit midvisible single-scatter albedos (approx. 0.89 to 0.93) obtained from the TARFOX flux comparisons are in accord with values derived by independent techniques. In ACE-2 we measured optical depth and extinction spectra for both European urban-marine aerosols and free-tropospheric African dust aerosols, using sunphotometers on the R/V Vodyanitskiy and the Pelican. Preliminary values for the radiative flux sensitivities (Delta Flux / Delta Optical depth) computed for ACE-2 aerosols (boundary layer and African dust) over ocean are similar to those found in TARFOX. Combining a satellite-derived optical depth climatology with the aerosol optical model validated for flux sensitivities in TARFOX provides first-cut estimates of aerosol-induced flux changes over the Atlantic Ocean.

  19. Climatological Impact of Atmospheric River Based on NARCCAP and DRI-RCM Datasets

    NASA Astrophysics Data System (ADS)

    Mejia, J. F.; Perryman, N. M.

    2012-12-01

    This study evaluates spatial responses of extreme precipitation environments, typically associated with Atmospheric River events, using Regional Climate Model (RCM) output from NARCCAP dataset (50km grid size) and the Desert Research Institute-RCM simulations (36 and 12 km grid size). For this study, a pattern-detection algorithm was developed to characterize Atmospheric Rivers (ARs)-like features from climate models. Topological analysis of the enhanced elongated moisture flux (500-300hPa; daily means) cores is used to objectively characterize such AR features in two distinct groups: (i) zonal, north Pacific ARs, and (ii) subtropical ARs, also known as "Pineapple Express" events. We computed the climatological responses of the different RCMs upon these two AR groups, from which intricate differences among RCMs stand out. This study presents these climatological responses from historical and scenario driven simulations, as well as implications for precipitation extreme-value analyses.

  20. Mapping of coupling hot spots of satellite derived latent heat flux in indian agro-climatic regions

    NASA Astrophysics Data System (ADS)

    Choudhury, I.

    2014-11-01

    This study focuses on the understanding and mapping of coupling hotspots of LE versus terrestrial and meteorological parameters. Single source surface energy balance model was used to derive surface energy balance parameters. Agro climatic region wise monthly information of terrestrial, energy balance and meteorological parameters were derived during June- September from decadal analysis of MODIS data (2003-2012) over India (68-100°E, 5-40°N) at 5 km spatial resolution. Information on rainfall was obtained from gridded rainfall data (1° × 1° spatial resolution) from Indian Meteorological Department (IMD). The spatiotemporal variability of the parameters such as rainfall, evapotranspiration (ET), evaporative fraction (EF), soil water index (SWI), land surface temperature (LST) and air temperature (Ta) showed strong influence on seasonal LE fluctuation. LE showed positive linear coupling with ET (0.52

  1. Scaling water and energy fluxes in climate system: Three land-atmospheric modeling experiments

    SciTech Connect

    Wood, E.F.; Lakshmi, V. )

    1993-05-01

    The effects of small-scale heterogeneity in land-surface characteristics on the large-scale fluxes of water and energy in the land-atmosphere system have become a central focus of many of the climatology research experiments. The acquisition of high-resolution land-surface data through remote sensing and intensive land-climatology field experiments (like HAPEX and FIFE) has provided data to investigate the interactions between microscale land-atmosphere interactions and macroscale models. One essential research question is how to account for the small-scale heterogeneities and whether [open quotes]effective[close quotes] parameters can be used in the macroscale models. To address this question of scaling, three modeling experiments were performed and are reviewed in the paper. The first is concerned with the land-surface hydrology during rain events and between rain events. The second experiment applies the Simple Biosphere Model (SiB) to a heterogeneous domain and the spatial and temporal latent heat flux is analyzed. The third experiment uses thermatic mapper (TM) data to look at the scaling of the normalized vegetation index (NDVI), latent heat flux, and sensible heat flux through either scaling of the TM-derived fields using the TM data or the fields derived from aggregated TM data. In all three experiments it was found that the surface fluxes and land characteristics can be scaled, and that macroscale models based on effective parameters are sufficient to account for the small-scale heterogeneities investigated. The paper also suggests that the scale at which a macroscale model becomes valid, the representative elementary scale (REA), is on the order 1.5-3 correlation lengths, which for land processes investigated appears to be about 1000-1500 m. At scales less than the REA scale, exact patterns of subgrid heterogeneities are needed for accurate small-scale modeling. 31 refs., 19 figs.

  2. Flux-creep activation energy for a BaFe1.9Ni0.1As2 single crystal derived from alternating current susceptibility measurements

    NASA Astrophysics Data System (ADS)

    Ge, Jun-Yi; Li, Lin-Jun; Xu, Zhu-An; Moshchalkov, Victor V.

    2016-04-01

    Systematic ac susceptibility measurements have been performed to investigate the vortex dynamics in a BaFe1.9Ni0.1As2 single crystal as a function of temperature, frequency, ac field amplitude, and dc magnetic field. The complex activation energy U ( T , B , j ) is derived in the framework of thermally activated flux creep theory and can be expressed in one simple formula. A power law dependence of U ˜ B α with α = -0.46 is observed. The activation energy reaches 104 K at low fields, suggesting strong pinning in the material. The nonlinear function of the activation energy vs. the current density is determined, which has the expression of U ∝ j - 0.1 .

  3. Local time variation of high-frequency gravity wave momentum flux and its relationship with background wind derived from LIDAR measurements

    NASA Astrophysics Data System (ADS)

    Agner, R. M.; Liu, A. Z.

    2013-12-01

    Gravity waves and atmospheric tides have strong interactions in the mesopause region and is a major contributor to the large variabilities in this region. How these two large perturbations interact with each other is not well understood. Observational studies of their relationships are needed to help clarify some contradictory results from modeling studies. Due to large differences in temporal and spatial scales between gravity waves and tides, they are not easily observed simultaneously and consistently with extended periods of time. In this work, we use four-hundred hours of Na LIDAR observation at Starfire Optical Range (SOR, 35.0 N, 106.5 W), New Mexico to derive the local time variation of gravity wave momentum flux and corresponding background wind. Their relationship is then examined in detail. The effects of gravity waves on the background wind at the tidal time scale are deduced. These results are explained through gravity wave propagation in a varying background atmosphere.

  4. Comparison of 37 months global net radiation flux derived from PICARD-BOS over the same period observations of CERES and ARGO

    NASA Astrophysics Data System (ADS)

    Zhu, Ping; Wild, Martin

    2016-04-01

    The absolute level of the global net radiation flux (NRF) is fixed at the level of [0.5-1.0] Wm-2 based on the ocean heat content measurements [1]. The space derived global NRF is at the same order of magnitude than the ocean [2]. Considering the atmosphere has a negligible effects on the global NRF determination, the surface global NRF is consistent with the values determined from space [3]. Instead of studying the absolute level of the global NRF, we focus on the interannual variation of global net radiation flux, which were derived from the PICARD-BOS experiment and its comparison with values over the same period but obtained from the NASA-CERES system and inferred from the ocean heat content survey by ARGO network. [1] Allan, Richard P., Chunlei Liu, Norman G. Loeb, Matthew D. Palmer, Malcolm Roberts, Doug Smith, and Pier-Luigi Vidale (2014), Changes in global net radiative imbalance 1985-2012, Geophysical Research Letters, 41 (no.15), 5588-5597. [2] Loeb, Norman G., John M. Lyman, Gregory C. Johnson, Richard P. Allan, David R. Doelling, Takmeng Wong, Brian J. Soden, and Graeme L. Stephens (2012), Observed changes in top-of-the-atmosphere radiation and upper-ocean heating consistent within uncertainty, Nature Geoscience, 5 (no.2), 110-113. [3] Wild, Martin, Doris Folini, Maria Z. Hakuba, Christoph Schar, Sonia I. Seneviratne, Seiji Kato, David Rutan, Christof Ammann, Eric F. Wood, and Gert Konig-Langlo (2015), the energy balance over land and oceans: an assessment based on direct observations and CMIP5 climate models, Climate Dynamics, 44 (no.11-12), 3393-3429.

  5. The reactivity of plant-derived organic matter in the Amazon River and implications on aquatic carbon fluxes to the atmosphere and ocean

    NASA Astrophysics Data System (ADS)

    Ward, N. D.; Sawakuchi, H. O.; Keil, R. G.; da Silva, R.; Brito, D. C.; Cunha, A. C.; Gagne-Maynard, W.; de Matos, A.; Neu, V.; Bianchi, T. S.; Krusche, A. V.; Richey, J. E.

    2014-12-01

    The remineralization of terrestrially-derived organic carbon (OC), along with direct CO2 inputs from autochthonous plant respiration in floodplains, results in an evasive CO2 gas flux from inland waters that is an order of magnitude greater than the flux of OC to the ocean. This phenomenon is enhanced in tropical systems as a result of elevated temperatures and productivity relative to temperate and high-latitude counterparts. Likewise, this balance is suspected to be influenced by increasing global temperatures and alterations to hydrologic and land use regimes. Here, we assess the reactivity of terrestrial and aquatic plant-derived OM near the mouth of the Amazon River. The stable isotopic signature of CO2 (δ13CO2) was monitored in real-time during incubation experiments performed in a closed system gas phase equilibration chamber connected to a Picarro Cavity Ring-Down Spectrometer. Incubations were performed under natural conditions and with the injection of isotopically labeled terrestrial macromolecules (e.g. lignin) and algal fatty acids. Under natural conditions, δ13CO2 became more depleted, shifting from roughly -23‰ to -27‰ on average, suggesting that C3 terrestrial vegetation was the primary fuel for CO2 production. Upon separate injections of 13C-labeled lignin and algal fatty acids, δ13CO2 increased near instantaneously and peaked in under 12 hours. Roughly 75% of the labeled lignin was converted to CO2 at the peak in δ13CO2, whereas less than 20% of the algal fatty acids were converted to CO2 (preliminary data subject to change). The rate of labeled-OC remineralization was enhanced by the addition of a highly labile substrate (e.g. ethyl acetate). Likewise, constant measurements of O2/pCO2 along the lower river revealed anomalously high CO2 and low O2 levels near the confluence of the mainstem and large tributaries with high algal productivity. These collective results suggest that the remineralization of complex terrestrial macromolecules is

  6. Building a field- and model-based climatology of local water and energy cycles in the cultivated Sahel - annual budgets and seasonality

    NASA Astrophysics Data System (ADS)

    Velluet, C.; Demarty, J.; Cappelaere, B.; Braud, I.; Issoufou, H. B.-A.; Boulain, N.; Ramier, D.; Mainassara, I.; Charvet, G.; Boucher, M.; Chazarin, J.-P.; Oï, M.; Yahou, H.; Maidaji, B.; Arpin-Pont, F.; Benarrosh, N.; Mahamane, A.; Nazoumou, Y.; Favreau, G.; Seghieri, J.

    2014-05-01

    In the African Sahel, energy and water cycling at the land surface is pivotal for regional climate, water resources and land productivity, yet it is still extremely poorly documented. As a step towards a comprehensive climatological description of surface fluxes in this area, this study provides estimates of average annual budgets and seasonal cycles for two main land use types of the cultivated Sahelian belt, rainfed millet crop and fallow bush. These estimates build on the combination of a 7 year field dataset from two typical plots in southwestern Niger with detailed physically-based soil-plant-atmosphere modelling, yielding a continuous, comprehensive set of water and energy flux and storage variables over the 7 year period. In this study case in particular, blending field data with mechanistic modelling is considered as making best use of available data and knowledge for such purpose. It extends observations by reconstructing missing data and extrapolating to unobserved variables or periods. Furthermore, model constraining with observations compromises between extraction of observational information content and integration of process understanding, hence accounting for data imprecision and departure from physical laws. Climatological averages of all water and energy variables, with associated sampling uncertainty, are derived at annual to subseasonal scales from the 7 year series produced. Similarities and differences in the two ecosystems behaviors are highlighted. Mean annual evapotranspiration is found to represent ~82-85% of rainfall for both systems, but with different soil evaporation/plant transpiration partitioning and different seasonal distribution. The remainder consists entirely of runoff for the fallow, whereas drainage and runoff stand in a 40-60% proportion for the millet field. These results should provide a robust reference for the surface energy- and water-related studies needed in this region. The model developed in this context has the

  7. Regional Climatology and Surface Radiation Budget

    NASA Technical Reports Server (NTRS)

    Wilber, Anne C.; Smith, G. Louis; Stackhouse, Paul W., Jr.

    1999-01-01

    The climatology and surface radiation budget (SRB) of a region are intimately related. This paper presents a brief examination of this relationship. An 8-year surface radiation budget data set has been developed based on satellite measurements. In that data set and in this paper a region is defined as a quasi-square 2.5o in latitude and approximately the same physical distance in longitude. A pilot study by Wilber et al. (1998) showed a variety of behaviors of the annual cycles for selected regions. Selected desert regions form a loop in a specific part of the plot, with large NLW and large NSW. Tropical wet regions form much smaller loops in a different part of the plot, with small NLW and large NSW. For regions selected in high latitude the annual cycles form nearly linear figures in another part of the plot. The question arises as to whether these trajectories are characteristic of the climatology of the region or simply the behavior of the few regions selected from the set of 6596 regions. In order to address this question, it is necessary to classify the climatology of the each region, e.g. as classified by Koeppen (1936) or Trenwarthe and Horne (1980). This paper presents a method of classifying climate of the regions on the basis of the surface radiation behavior such that the results are very similar to the classification of Trenwarthe and Horne. The characteristics of the annual cycle of SRB components can then be investigated further, based on the climate classification of each region.

  8. A new climatological oceanic eddy census

    NASA Astrophysics Data System (ADS)

    Mason, Evan; Pascual, Ananda; Pujol, Isabel; Faugère, Yannice; Delepoulle, Antoine; Briol, Frederic

    2015-04-01

    We present a new climatological oceanic eddy census dataset based on gridded sea level anomalies from satellite altimeter observations that is due for release by Archiving, Validation and Interpretation of Satellite Oceanographic data (AVISO). The identification and automated tracking of oceanic eddies is carried out using the py-eddy-tracker of Mason et al. (2014). Daily outputs of eddy properties (including position, radius, amplitude and nonlinearity) covering the period 1993-2013 over the global domain are presented and discussed. Validation and comparison is made with the published global eddy track database of Chelton et al. (2011).

  9. On the impacts of phytoplankton-derived organic matter on the properties of the primary marine aerosol - Part 1: Source fluxes

    NASA Astrophysics Data System (ADS)

    Fuentes, E.; Coe, H.; Green, D.; de Leeuw, G.; McFiggans, G.

    2010-10-01

    , which revealed a higher production of particles with Dp0<100 nm at regions with high biological activity. These findings suggest that the increase in the atmospheric aerosol modal sizes from winter to summer, reported by long-term observations in North Atlantic waters, is not directly due to an impact of the higher primary organic matter production occurring during warm periods. A novel sub-micrometric size-resolved source flux function, explicitly defined as a function of the diatomaceous exudate concentration, was derived from the size distribution measurements and the estimation of the fractional whitecap coverage. According to the defined parameterisation, a 300 μM OC<0.2 μm concentration of diatomaceous exudate in seawater produces an overall increment in the total source particle flux of ~20% with respect to the organics-free seawater case. The effect increases with decreasing particle size for Dp0<100 nm, resulting in multiplicative factors between 1.02-2 with respect to the particle flux generated from seawater devoid of marine organics. The total source flux derived from the presented parameterisation was compared to recent definitions of sea-spray source fluxes based on laboratory and field observations in the literature.

  10. Do Australian sclerophyll forests exhibit seasonality? an analysis with phenocam, eddy covariance fluxes, and satellite derived phenology.

    NASA Astrophysics Data System (ADS)

    Restrepo-Coupe, N.; Huete, A. R.; Davies, K.; Macfarlane, C.; Beringer, J.; Van Gorsel, E.; Maier, C.; Resco de Dios, V.

    2014-12-01

    Temperate broadleaf evergreen forests in Australia exhibit characteristically unique and contradictory seasonality behaviors with strongly seasonal gross primary productivity (GPP) values and weak to no seasonality in satellite-derived vegetation indices (VIs), leaf area index (LAI), and fraction of absorbed photosynthetically active radiation (fPAR). As part of adaptation strategies to highly variable rainfall and water balance deficit conditions, sclerophyll forests allocate carbon to long-lived, thick leaves with low water content, and generally exhibit small seasonal changes in canopy infrastructure (LAI). Erectophile leaf angle distributions, and/or differences in leaf adaxial and abaxial optical properties allow the leaves to achieve thermal protection. However, these leaf traits complicate any spectral analysis and the study of sclerophyll forest phenology. Our goal was to utilize tower mounted phenocam imagery of whole-canopy, multiple tree crowns, and understory layers to trace multi-functional phenology profiles at three sclerophyll forest sites (one banksia dominated and two eucalyptus dominated) all part of the Terrestrial Ecosystem Research Network (TERN). We contrast and compare in-situ phenocam time series data with satellite vegetation products from the Moderate Resolution Imaging Spectroradiometer (MODIS), and eddy covariance measures of ecosystem built photosynthetic capacity (ecosystem light use efficiency, LUE, and chlorophyll fPAR). We found that at sclerophyll forests, despite ecosystem photosynthetic capacity exhibiting weak seasonality, climate and in particular rainfall pulses, drove diverse responses over each of the different forest components (e.g. overstory and understory). Interestingly, tree and understory growing and browning cycles were out-of phase, and contributed to the characteristic VI seasonality behavior of the whole ecosystem.

  11. Distance and luminosity probability distributions derived from parallax and flux with their measurement errors. With application to the millisecond pulsar PSR J0218+4232

    NASA Astrophysics Data System (ADS)

    Igoshev, Andrei; Verbunt, Frank; Cator, Eric

    2016-06-01

    We use a Bayesian approach to derive the distance probability distribution for one object from its parallax with measurement uncertainty for two spatial distribution priors, a homogeneous spherical distribution and a galactocentric distribution - applicable for radio pulsars - observed from Earth. We investigate the dependence on measurement uncertainty, and show that a parallax measurement can underestimate or overestimate the actual distance, depending on the spatial distribution prior. We derive the probability distributions for distance and luminosity combined - and for each separately when a flux with measurement error for the object is also available - and demonstrate the necessity of and dependence on the luminosity function prior. We apply this to estimate the distance and the radio and gamma-ray luminosities of PSR J0218+4232. The use of realistic priors improves the quality of the estimates for distance and luminosity compared to those based on measurement only. Use of the wrong prior, for example a homogeneous spatial distribution without upper bound, may lead to very incorrect results.

  12. Lightning Climatology with a Generalized Additive Model

    NASA Astrophysics Data System (ADS)

    Simon, Thorsten; Mayr, Georg; Umlauf, Nikolaus; Zeileis, Achim

    2016-04-01

    This study present a lightning climatology on a 1km x 1km grid estimated via generalized additive models (GAM). GAMs provide a framework to account for non-linear effects in time and space and for non-linear spatial-temporal interaction terms simultaneously. The degrees of smoothness of the non-linear effects is selected automatically in our approach. Furthermore, the influence of topography is captured in the model by including a non-linear term. To illustrate our approach we use lightning data from the ALDIS networks and selected a region in Southeastern Austria, where complex terrain extends from 200 an 3800 m asl and summertime lightning activity is high compared to other parts of the Eastern Alps. The temporal effect in the GAM shows a rapid increase in lightning activity in early July and a slow decay in activity afterwards. The estimated spatial effect is not very smooth and requires approximately 225 effective degrees of freedom. It reveals that lightning is more likely in the Eastern and Southern part of the region of interest. This spatial effect only accounts for variability not already explained by the topography. The topography effect shows lightning to be more likely at higher altitudes. The effect describing the spatio-temporal interactions takes approximately 200 degrees of freedom, and reveals local deviations of the climatology.

  13. Precipitation Climatology on Titan-like Exomoons.

    PubMed

    Tokano, Tetsuya

    2015-06-01

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

  14. A climatological analysis of Saharan cyclones

    NASA Astrophysics Data System (ADS)

    Ammar, K.; El-Metwally, Mossad; Almazroui, Mansour; Abdel Wahab, M. M.

    2014-07-01

    In this study, the climatology of Saharan cyclones is presented in order to understand the Saharan climate, its variability and its changes. This climatology includes an analysis of seasonal and interannual variations, the identification and classification of cyclone tracks, and a presentation of their chief characteristics. The data used are drawn from the 1980-2009, 2.5° × 2.5°, NCEP/NCAR reanalysis (NNRP I) dataset. It is found that cyclone numbers increase in September-October-November (SON) at 4.9 cyclones per decade, while they decrease in June-July-August at 12.3 cyclones per decade. The identification algorithm constructed 562 tracks, which are categorized into 12 distinct clusters. Around 75 % of the Saharan cyclones originate south of the Atlas Mountains. The percentage of tracks that move over the Sahara is around 48 %. The eastern Mediterranean receives 27 % of the Saharan tracks, while the western basin receives only 17 and 8 % of all the Saharan cyclones decay over the Arabian Peninsula. The maximum cyclonic activity occurs in April. There is a general decrease in the number of tracks in all categories between 1993 and 2009, compared with the period between 1980 and 1992. About 72 % of the Saharan cyclones do not live more than 3 days, and about 80 % of the cyclones in the tracks never reach central pressures 1,000 hPa during their lifetimes. The maximum deepening in the tracks occurs over the western Mediterranean and over northern Algeria.

  15. Precipitation Climatology on Titan-like Exomoons

    NASA Astrophysics Data System (ADS)

    Tokano, Tetsuya

    2015-06-01

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

  16. A Climatology of Global Aerosol Mixtures to Support Sentinel-5P and Earthcare Mission Applications

    NASA Astrophysics Data System (ADS)

    Taylor, M.; Kazadzis, S.; Amaridis, V.; Kahn, R. A.

    2015-06-01

    Since constraining aerosol type with satellite remote sensing continues to be a challenge, we present a newly derived global climatology of aerosol mixtures to support atmospheric composition studies that are planned for Sentinel-5P and EarthCARE. The global climatology is obtained via application of iterative cluster analysis to gridded global decadal and seasonal mean values of the aerosol optical depth (AOD) of sulfate, biomass burning, mineral dust and marine aerosol as a proportion of the total AOD at 500nm output from the Goddard Chemistry Aerosol Radiation and Transport (GOCART). For both the decadal and seasonal means, the number of aerosol mixtures (clusters) identified is ≈10. Analysis of the percentage contribution of the component aerosol types to each mixture allowed development of a straightforward naming convention and taxonomy, and assignment of primary colours for the generation of true colour-mixing and easy-to-interpret maps of the spatial distribution of clusters across the global grid. To further help characterize the mixtures, aerosol robotic network (AERONET) Level 2.0 Version 2 inversion products were extracted from each cluster's spatial domain and used to estimate climatological values of key optical and microphysical parameters. The aerosol type climatology represents current knowledge that would be enhanced, possibly corrected, and refined by high temporal and spectral resolution, cloud-free observations produced by Sentinel-5P and EarthCARE instruments. The global decadal mean and seasonal gridded partitions comprise a preliminary reference framework and global climatology that can help inform the choice of components and mixtures in aerosol retrieval algorithms used by instruments such as TROPOMI and ATLID, and to test retrieval results.

  17. Martian middle-atmosphere climatology from modern spacecraft

    NASA Astrophysics Data System (ADS)

    McDunn, Tamara; Bougher, Stephen; Forget, Francois; Kleinboehl, Armin; Tolson, Robert

    We construct a climatology from middle atmosphere (˜ 40-130 km) temperature and den-sity data from the following instruments: MEx/SPICAM, MRO/MCS, MGS/Accelerometer, ODY/Accelerometer, and MRO/Accelerometer. We examine the data for trends with latitude, local time, season, and solar cycle, thereby characterizing the structure and climactic patterns of the middle atmosphere using modern datasets. In this talk we identify significant middle-altitude climate patterns, including: winter polar warming (WPW), areas of sub-freezing tem-peratures, patterns of the middle-atmosphere temperature bulge, and patterns of the mesopause altitude and temperature. We also explore the implications of these patterns in the data. In brief, middle-atmosphere WPW indicates dynamical patterns linking the lower, middle, and upper atmospheres. Areas of sub-freezing temperatures indicate locations where CO2 clouds can be expected to form. Finally, the temperature bulge and mesopause patterns identified again suggest distinct large-scale circulations. These results support previous findings that solar flux, lower-atmosphere dust loading, and gravity waves from the lower atmosphere sub-stantially impact the wind systems of the middle atmosphere and the resulting distribution of energy.

  18. DL0805-2, a novel indazole derivative, relaxes angiotensin II-induced contractions of rat aortic rings by inhibiting Rho kinase and calcium fluxes

    PubMed Central

    Yuan, Tian-yi; Chen, Yu-cai; Zhang, Hui-fang; Li, Li; Jiao, Xiao-zhen; Xie, Ping; Fang, Lian-hua; Du, Guan-hua

    2016-01-01

    Aim: DL0805-2 [N-(1H-indazol-5-yl)-1-(4-methylbenzyl) pyrrolidine-3-carboxamide] is a DL0805 derivative with more potent vasorelaxant activity and lower toxicity. This study was conducted to investigate the vasorelaxant mechanisms of DL0805-2 on angiotensin II (Ang II)-induced contractions of rat thoracic aortic rings in vitro. Methods: Rat thoracic aortic rings and rat aortic vascular smooth muscle cells (VSMCs) were pretreated with DL0805-2, and then stimulated with Ang II. The tension of the aortic rings was measured through an isometric force transducer. Ang II-induced protein phosphorylation, ROS production and F-actin formation were assessed with Western blotting and immunofluorescence assays. Intracellular free Ca2+ concentrations were detected with Fluo-3 AM. Results: Pretreatment with DL0805-2 (1–100 μmol/L) dose-dependently inhibited the constrictions of the aortic rings induced by a single dose of Ang II (10−7 mol/L) or accumulative addition of Ang II (10−10–10−7 mol/L). The vasodilatory effect of DL0805-2 was independent of endothelium. In the aortic rings, pretreatment with DL0805-2 (1, 3, and 10 μmol/L) suppressed Ang II-induced Ca2+ influx and intracellular Ca2+ mobilization, and Ang II-induced phosphorylation of two substrates of Rho kinase (MLC and MYPT1). In VSMCs, pretreatment with DL0805-2 (1, 3, and 10 μmol/L) also suppressed Ang II-induced Ca2+ fluxes and phosphorylation of MLC and MYPT1. In addition, pretreatment with DL0805-2 attenuated ROS production and F-actin formation in the cells. Conclusion: DL0805-2 exerts a vasodilatory action in rat aortic rings through inhibiting the Rho/ROCK pathway and calcium fluxes. PMID:27041459

  19. Long-term records of global radiation, carbon and water fluxes derived from multi-satellite data and a process-based model

    NASA Astrophysics Data System (ADS)

    Ryu, Youngryel; Jiang, Chongya

    2016-04-01

    To gain insights about the underlying impacts of global climate change on terrestrial ecosystem fluxes, we present a long-term (1982-2015) global radiation, carbon and water fluxes products by integrating multi-satellite data with a process-based model, the Breathing Earth System Simulator (BESS). BESS is a coupled processed model that integrates radiative transfer in the atmosphere and canopy, photosynthesis (GPP), and evapotranspiration (ET). BESS was designed most sensitive to the variables that can be quantified reliably, fully taking advantages of remote sensing atmospheric and land products. Originally, BESS entirely relied on MODIS as input variables to produce global GPP and ET during the MODIS era. This study extends the work to provide a series of long-term products from 1982 to 2015 by incorporating AVHRR data. In addition to GPP and ET, more land surface processes related datasets are mapped to facilitate the discovery of the ecological variations and changes. The CLARA-A1 cloud property datasets, the TOMS aerosol datasets, along with the GLASS land surface albedo datasets, were input to a look-up table derived from an atmospheric radiative transfer model to produce direct and diffuse components of visible and near infrared radiation datasets. Theses radiation components together with the LAI3g datasets and the GLASS land surface albedo datasets, were used to calculate absorbed radiation through a clumping corrected two-stream canopy radiative transfer model. ECMWF ERA interim air temperature data were downscaled by using ALP-II land surface temperature dataset and a region-dependent regression model. The spatial and seasonal variations of CO2 concentration were accounted by OCO-2 datasets, whereas NOAA's global CO2 growth rates data were used to describe interannual variations. All these remote sensing based datasets are used to run the BESS. Daily fluxes in 1/12 degree were computed and then aggregated to half-month interval to match with the spatial

  20. A comparison of ground-based and satellite-derived radiative heat flux at Mt Etna: the 12 August lava fountain case study

    NASA Astrophysics Data System (ADS)

    Ganci, Gaetana; Calvari, Sonia; James, Mike; Del Negro, Ciro

    2013-04-01

    The recent eruptive activity at Mt Etna has been characterized by quiet frequent, intermittent episodes of lava fountains associated with small lava flow output, occurring especially at the SE Crater. During 2011, 18 paroxysmal lava fountains were produced by a new cone, named "Sturiale Cone", on the east flank of the SE Crater. Given the high hazard posed by this activity, and the need of improving detection, description and knowledge of these events, remote monitoring through fixed cameras and satellites has becoming crucial, especially using thermal sensors. We here focus on the 12 August 2011 episode, the strongest of the lava fountains occurred in 2011, and also the best monitored, given the clear sky, absence of clouds, and possibility to collect also images from a close-up view. We disposed of a total of 8 fixed cameras working around the volcano, three of them offering a thermal view of the episode. Moreover, as satellite observations, we could use the complete data set from the SEVIRI sensor, which has a temporal resolution of 15 minutes. To compare the field- and satellite-derived radiative heat flux curves, thermal images were registered by taking into account a DEM, the GPS camera position, the relative camera rotations and first order lens distortion parameters. Moreover, it was performed a pixel by pixel correction from path length and atmospheric effects. Finally, a temperature threshold was fixed to identify the active lava area and the amount of heat lost by radiation from all the pixels covered by lava was computed. SEVIRI data were analyzed by the HOTSAT thermal monitoring system. Through automatic hot-spot detection algorithm based on dynamic thresholds, we are able to provide an estimate of the radiant heat flux for each thermally anomalous pixel and possibly convert it into time averaged discharge rate. Preliminary results showed a good agreement on timing, shape and amplitude of the radiative heat flux time series between thermal camera and

  1. The Global Precipitation Climatology Centre (GPCC) - in situ observation based precipitation climatology on regional and global scale

    NASA Astrophysics Data System (ADS)

    Fuchs, T.; Schneider, U.; Rudolf, B.

    2009-04-01

    The Global Precipitation Climatology Centre (GPCC, http://gpcc.dwd.de) provides global monthly precipitation analyses for monitoring and research of the earth's climate. The centre is a German contribution to the World Climate Research Programme (WCRP), to the Global Climate Observing System (GCOS), and to the Global Earth Observation System of Systems (GEOSS). It contributes to water resources assessments, flood and drought monitoring, climate variability and trend analyses. GPCC published in year 2008 a new global precipitation climatology as well as a reanalysis of its full data base for all months of the period 1901-2007. The GPCC data base comprises monthly precipitation totals from more than 70 000 different stations in the world. It produces gridded data sets of monthly precipitation on the earth's land surface derived from raingauge based observation data. Intensive quality control of observation data and station metadata ensures a high analysis quality. The different GPCC products are adjusted to different user needs. It routinely produces 2 near real-time precipitation monitoring products. Its 2 non real-time products are updated at irregular time intervals after significant updates of its observation station database. All GPCC products can be visualised and accessed free of charge via Internet from http://gpcc.dwd.de. The GPCC First Guess Product of the monthly precipitation anomaly is based on synoptic weather reports (SYNOP) from about 6,300 stations worldwide received near real-time via the WMO Global Telecommunication System (GTS). The product is available within 5 days after end of an observation month. Main application purpose is near real-time drought monitoring. The product uses since mid 2008 the new GPCC monthly precipitation climatology as analysis background. Spatial product resolution: 1.0° and 2.5°. The GPCC Monitoring Product of monthly precipitation is based on SYNOP and monthly CLIMAT reports received near real-time via GTS from about

  2. Multi-summer Cumulus-Radiation-Aerosol Climatology at SGP site

    NASA Astrophysics Data System (ADS)

    Kassianov, E.; Berg, L. K.; Flynn, C.; Long, C.; Barnard, J.

    2010-12-01

    Compared to other cloud types, shallow cumulus clouds are relatively small in size and have large variations over time/space that are poorly captured by current large-scale models of the atmosphere. Since these small-scale variations are very difficult to monitor and accurately describe, models improvement is hampered, in part, by the lack of appropriate observational constraints, including cloud and aerosol properties, surface parameters and radiative fluxes. To address this issue, a multi-summer (2000-2007) cumulus-radiation-aerosol climatology has been developed for the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Site. In particular, this climatology is applied to illustrate that positive values of shortwave cloud radiative forcing occur frequently and are characterized by fluctuations with a small temporal scale; the duration for the majority of events with positive radiative forcing is less than 5 minutes. In this presentation, the developed climatology will be described and several important applications will be shown.

  3. Hanford Site Climatological Data Summary 1998

    SciTech Connect

    DJ Hoitink; JV Ramsdell; KW Burk

    1999-05-26

    This document presents the climatological data measured at the U.S. Department of Energy's Hanford Site for calendar year 1998. Pacific Northwest National Laboratory operates the Hanford Meteorology Station and the Hanford Meteorological Monitoring Network from which these data were collected. The information contained herein includes updated historical climatologies for temperature; precipitation, normal and extreme values of temperature and precipitation and other miscellaneous meteorological parameters. Further, the data are adjunct to and update Hoitink and Burk (1994, 1995, 1996, 1997, 1998); however, Appendix B--Wind Climatology (1994) is excluded. 1998 was much warmer than normal, tying 1992 as the warmest year on record. The average temperature was 56.4 F, 3.1 F above normal (53.3 F). The highest July temperature ever recorded was 112 F on July 27, 1998. The first week in May, three daily temperature records were broken or tied. November 1998 was the third warmest on record. For the year 1998, there were 73 days with maximum temperature >90 F, the third highest on record. For the 12-month period, 11 months were warmer than normal and 1 was cooler than normal. The summer (June, July, and August) and autumn (September, October, and November) of 1998 were the fourth warmest on record. 1998 was slightly wetter than normal. Precipitation totaled 6.45 in., 103% of normal (6.26 in.); snow-fall totaled 7.2 in., compared to the normal of 13.8 in. There were eight thunderstorms recorded at Hanford Meteorological Station in July 1998, tying 1983 for the most thunderstorms in July. The average wind speed during 1998 was 7.9 mph, 0.2 mph above normal (7.7 mph). There were 32 days with peak gusts {ge}40 mph, compared to a yearly average of 26 mph. The peak gust during the year was 56 mph from the south-southwest on November 21. November 1998 had a record number of days (10) with wind gusts {ge}40 mph. The heating-degree days for 1997-1998 were 4,523 (14% below the 5

  4. Metrological challenges for measurements of key climatological observables Part 2: oceanic salinity

    NASA Astrophysics Data System (ADS)

    Pawlowicz, R.; Feistel, R.; McDougall, T. J.; Ridout, P.; Seitz, S.; Wolf, H.

    2016-02-01

    Salinity is a key variable in the modelling and observation of ocean circulation and ocean-atmosphere fluxes of heat and water. In this paper, we examine the climatological relevance of ocean salinity, noting fundamental deficiencies in the definition of this key observable, and its lack of a secure foundation in the International System of Units, the SI. The metrological history of salinity is reviewed, problems with its current definitions and measurement practices are analysed, and options for future improvements are discussed in conjunction with the recent seawater standard TEOS-10.

  5. 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.

  6. Climatology of fog in SW-Iceland

    NASA Astrophysics Data System (ADS)

    Barranco, Aurelio; Ólafsson, Haraldur

    2016-04-01

    The climatology of fog in Keflavik Airport in Southwest-Iceland has been investigated for the latter half of the 20th Century. Fog is twice as frequent in the late night than in the afternoon, suggesting important, but not dominating, impact of the diurnal cycle. There is large interannual variability in the frequency of fog, but no clear long-term trend. However, there is a clear shift in seasonal frequency; the period 1953-1977 had relatively frequent fog in the autumn, while 1978-1998, fog is relatively frequent in the spring and summer. This indicates sensitivity of the fog to mean sea surface temperatures. An attempt is made to assess frequency of fog in climate scenarii.

  7. Climatology of Urban-regional Systems

    NASA Technical Reports Server (NTRS)

    Pease, R. W.

    1971-01-01

    Urbanized areas have come to be significant if not dominant components of many regional land surfaces. They represent perhaps the most dramatic recent change man has made in his environment - a change that may well burgeon in the foreseeable future as greater percentages of world populations crowd into metropolitan areas. The climate of urban-regional systems is involved because temperature, air, and pollutants added to the air are significant aspects of this change. During the past two years, substantial progress has been made in the application of remote sensing techniques to the study of urban climatology by programs jointly sponsored by NASA and the United States Geological Survey. The initial effort has endeavored with considerable success to map terrestrial radiation emission or the general thermal state of the land surface with the aid of imaging radiometers (mechanical-optical scanners).

  8. Tohono O'odham Monsoon Climatology

    NASA Astrophysics Data System (ADS)

    Ackerman, G.

    2006-12-01

    The North American monsoon is a summertime weather phenomenon that develops over the southwestern North America. For thousands of years the Tohono O'odham people of this area have depended on the associated rainy season (Jukiabig Masad) to grow traditional crops using runoff agriculture. Today, the high incidence of Type II diabetes among native people has prompted many to return to their traditional agricultural diets. Local monsoon onset dates and the North American Regional Reanalysis dataset were used to develop a 24-year Tohono O'odham Nation (TON) monsoon and pre-monsoon climatology that can be used as a tool for planning runoff agriculture. Using monsoon composite datasets, temporal and spatial correlations between antecedent period meteorological variables, monsoon onset dates and total monsoon precipitation were examined to identify variables that could be useful in predicting the onset and intensity of the monsoon. The results suggest additional research is needed to identify variables related to monsoon onset and intensity.

  9. Inner Radiation Belt Dynamics and Climatology

    NASA Astrophysics Data System (ADS)

    Guild, T. B.; O'Brien, P. P.; Looper, M. D.

    2012-12-01

    We present preliminary results of inner belt proton data assimilation using an augmented version of the Selesnick et al. Inner Zone Model (SIZM). By varying modeled physics parameters and solar particle injection parameters to generate many ensembles of the inner belt, then optimizing the ensemble weights according to inner belt observations from SAMPEX/PET at LEO and HEO/DOS at high altitude, we obtain the best-fit state of the inner belt. We need to fully sample the range of solar proton injection sources among the ensemble members to ensure reasonable agreement between the model ensembles and observations. Once this is accomplished, we find the method is fairly robust. We will demonstrate the data assimilation by presenting an extended interval of solar proton injections and losses, illustrating how these short-term dynamics dominate long-term inner belt climatology.

  10. A Variational Analysis of Divergence Profiles Based upon Column-Integrated Mass, Moisture and Energetic Constraints with Satellite-Derived Boundary Fluxes

    NASA Technical Reports Server (NTRS)

    Lu, Huei-Lin; Robertson, Franklin R.

    2003-01-01

    A diagnostic study is made of the mean global divergent circulation based upon a constrained least action principle that minimizes column-integrated divergent kinetic energy subject to constraints on mass, moisture, available potential energy (ape) and total kinetic energy. The concept of gross moist stability was incorporated in the prescription of Lagrange weight function associated with the ape constraint in order to simulate the net effects of cumulus convective heating in the tropics. The variational analyses were validated satisfactorily with the original NCEP/NCAR-reanalysis divergence fields for the Septembers of 1987 and 1988. Further analyses show that in the tropical ascending regions, the analyzed divergences are dominated by the mass and ape constraints; the moisture constraint is implicitly satisfied while the kinetic energy constraint is highly dependent on the ape constraint. In the subtropical descending regions, the analyzed divergences are dominated by the mass, moisture and kinetic energy constraints; the ape constraint is implicitly satisfied. When the constraint integrals were blended with the satellite-derived boundary flux data from GPCP precipitation and ERBE/SRB radiation estimates, the newly analyzed divergences are significantly stronger than the reanalysis divergences in the areas where the estimates of precipitation rates are higher. With few exceptions, the increases in upper-layer divergences are coupled with nearly equal increases in lower-layer convergences.