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Sample records for nasa-modified precipitation products

  1. NASA-modified precipitation products to improve USEPA nonpoint source water quality modeling for the Chesapeake Bay.

    PubMed

    Nigro, Joseph; Toll, David; Partington, Ed; Ni-Meister, Wenge; Lee, Shihyan; Gutierrez-Magness, Angelica; Engman, Ted; Arsenault, Kristi

    2010-01-01

    The USEPA has estimated that over 20,000 water bodies within the United States do not meet water quality standards. One of the regulations in the Clean Water Act of 1972 requires states to monitor the total maximum daily load, or the amount of pollution that can be carried by a water body before it is determined to be "polluted," for any watershed in the United States (Copeland, 2005). In response to this mandate, the USEPA developed Better Assessment Science Integrating Nonpoint Sources (BASINS) as a decision support tool for assessing pollution and to guide the decision-making process for improving water quality. One of the models in BASINS, the Hydrological Simulation Program-Fortran (HSPF), computes continuous streamflow rates and pollutant concentration at each basin outlet. By design, precipitation and other meteorological data from weather stations serve as standard model input. In practice, these stations may be unable to capture the spatial heterogeneity of precipitation events, especially if they are few and far between. An attempt was made to resolve this issue by substituting station data with NASA-modified/NOAA precipitation data. Using these data within HSPF, streamflow was calculated for seven watersheds in the Chesapeake Bay Basin during low flow periods, convective storm periods, and annual flows. In almost every case, the modeling performance of HSPF increased when using the NASA-modified precipitation data, resulting in better streamflow statistics and, potentially, in improved water quality assessment.

  2. NASA-Modified Precipitation Products to Improve EPA Nonpoint Source Water Quality Modeling for the Chesapeake Bay

    NASA Technical Reports Server (NTRS)

    Nigro, Joseph; Toll, David; Partington, Ed; Ni-Meister, Wenge; Lee, Shihyan; Gutierrez-Magness, Angelica; Engman, Ted; Arsenault, Kristi

    2010-01-01

    The Environmental Protection Agency (EPA) has estimated that over 20,000 water bodies within the United States do not meet water quality standards. Ninety percent of the impairments are typically caused by nonpoint sources. One of the regulations in the Clean Water Act of 1972 requires States to monitor the Total Maximum Daily Load (TMDL), or the amount of pollution that can be carried by a water body before it is determined to be "polluted", for any watershed in the U.S.. In response to this mandate, the EPA developed Better Assessment Science Integrating Nonpoint Sources (BASINS) as a Decision Support Tool (DST) for assessing pollution and to guide the decision making process for improving water quality. One of the models in BASINS, the Hydrological Simulation Program -- Fortran (HSPF), computes daily stream flow rates and pollutant concentration at each basin outlet. By design, precipitation and other meteorological data from weather stations serve as standard model input. In practice, these stations may be unable to capture the spatial heterogeneity of precipitation events especially if they are few and far between. An attempt was made to resolve this issue by substituting station data with NASA modified/NOAA precipitation data. Using these data within HSPF, stream flow was calculated for seven watersheds in the Chesapeake Bay Basin during low flow periods, convective storm periods, and annual flows. In almost every case, the modeling performance of HSPF increased when using the NASA-modified precipitation data, resulting in better stream flow statistics and, ultimately, in improved water quality assessment.

  3. NASA-Modified Precipitation Products to Improve EPA Nonpoint Source Water Quality Modeling for the Chesapeake Bay

    NASA Technical Reports Server (NTRS)

    Nigro, Joseph; Toll, David; Partington, Ed; Ni-Meister, Wenge; Lee, Shihyan; Gutierrez-Magness, Angelica; Engman, Ted; Arsenault, Kristi

    2010-01-01

    The Environmental Protection Agency (EPA) has estimated that over 20,000 water bodies within the United States do not meet water quality standards. Ninety percent of the impairments are typically caused by nonpoint sources. One of the regulations in the Clean Water Act of 1972 requires States to monitor the Total Maximum Daily Load (TMDL), or the amount of pollution that can be carried by a water body before it is determined to be "polluted", for any watershed in the U.S.. In response to this mandate, the EPA developed Better Assessment Science Integrating Nonpoint Sources (BASINS) as a Decision Support Tool (DST) for assessing pollution and to guide the decision making process for improving water quality. One of the models in BASINS, the Hydrological Simulation Program -- Fortran (HSPF), computes daily stream flow rates and pollutant concentration at each basin outlet. By design, precipitation and other meteorological data from weather stations serve as standard model input. In practice, these stations may be unable to capture the spatial heterogeneity of precipitation events especially if they are few and far between. An attempt was made to resolve this issue by substituting station data with NASA modified/NOAA precipitation data. Using these data within HSPF, stream flow was calculated for seven watersheds in the Chesapeake Bay Basin during low flow periods, convective storm periods, and annual flows. In almost every case, the modeling performance of HSPF increased when using the NASA-modified precipitation data, resulting in better stream flow statistics and, ultimately, in improved water quality assessment.

  4. Asymmetric responses of primary productivity to precipitation extremes: a synthesis of grassland precipitation manipulation experiments.

    PubMed

    Wilcox, Kevin R; Shi, Zheng; Gherardi, Laureano A; Lemoine, Nathan P; Koerner, Sally E; Hoover, David L; Bork, Edward; Byrne, Kerry M; Cahill, James; Collins, Scott L; Evans, Sarah; Katarina Gilgen, Anna; Holub, Petr; Jiang, Lifen; Knapp, Alan K; LeCain, Daniel; Liang, Junyi; Garcia-Palacios, Pablo; Peñuelas, Josep; Pockman, William T; Smith, Melinda D; Sun, Shanghua; White, Shannon R; Yahdjian, Laura; Zhu, Kai; Luo, Yiqi

    2017-04-02

    Climatic changes are altering Earth's hydrological cycle, resulting in altered precipitation amounts, increased inter-annual variability of precipitation, and more frequent extreme precipitation events. These trends will likely continue into the future, having substantial impacts on net primary productivity (NPP) and associated ecosystem services such as food production and carbon sequestration. Frequently, experimental manipulations of precipitation have linked altered precipitation regimes to changes in NPP. Yet, findings have been diverse and substantial uncertainty still surrounds generalities describing patterns of ecosystem sensitivity to altered precipitation. Additionally, we do not know whether previously observed correlations between NPP and precipitation remain accurate when precipitation changes become extreme. We synthesized results from 83 case studies of experimental precipitation manipulations in grasslands worldwide. We used meta-analytical techniques to search for generalities and asymmetries of aboveground NPP (ANPP) and belowground NPP (BNPP) responses to both the direction and magnitude of precipitation change. Sensitivity (i.e., productivity response standardized by the amount of precipitation change) of BNPP was similar under precipitation additions and reductions, but ANPP was more sensitive to precipitation additions than reductions; this was especially evident in drier ecosystems. Additionally, overall relationships between the magnitude of productivity responses versus the magnitude of precipitation change were saturating in form. The saturating form of this relationship was likely driven by ANPP responses to very extreme precipitation increases, although there were limited studies imposing extreme precipitation change and there was considerable variation among experiments. This highlights the importance of incorporating gradients of manipulations, ranging from extreme drought to extreme precipitation increases into future climate change

  5. Enhanced precipitation variability decreases grass- and increases shrub-productivity.

    PubMed

    Gherardi, Laureano A; Sala, Osvaldo E

    2015-10-13

    Although projections of precipitation change indicate increases in variability, most studies of impacts of climate change on ecosystems focused on effects of changes in amount of precipitation, overlooking precipitation variability effects, especially at the interannual scale. Here, we present results from a 6-y field experiment, where we applied sequences of wet and dry years, increasing interannual precipitation coefficient of variation while maintaining a precipitation amount constant. Increased precipitation variability significantly reduced ecosystem primary production. Dominant plant-functional types showed opposite responses: perennial-grass productivity decreased by 81%, whereas shrub productivity increased by 67%. This pattern was explained by different nonlinear responses to precipitation. Grass productivity presented a saturating response to precipitation where dry years had a larger negative effect than the positive effects of wet years. In contrast, shrubs showed an increasing response to precipitation that resulted in an increase in average productivity with increasing precipitation variability. In addition, the effects of precipitation variation increased through time. We argue that the differential responses of grasses and shrubs to precipitation variability and the amplification of this phenomenon through time result from contrasting root distributions of grasses and shrubs and competitive interactions among plant types, confirmed by structural equation analysis. Under drought conditions, grasses reduce their abundance and their ability to absorb water that then is transferred to deep soil layers that are exclusively explored by shrubs. Our work addresses an understudied dimension of climate change that might lead to widespread shrub encroachment reducing the provisioning of ecosystem services to society.

  6. Enhanced precipitation variability decreases grass- and increases shrub-productivity

    PubMed Central

    Gherardi, Laureano A.; Sala, Osvaldo E.

    2015-01-01

    Although projections of precipitation change indicate increases in variability, most studies of impacts of climate change on ecosystems focused on effects of changes in amount of precipitation, overlooking precipitation variability effects, especially at the interannual scale. Here, we present results from a 6-y field experiment, where we applied sequences of wet and dry years, increasing interannual precipitation coefficient of variation while maintaining a precipitation amount constant. Increased precipitation variability significantly reduced ecosystem primary production. Dominant plant-functional types showed opposite responses: perennial-grass productivity decreased by 81%, whereas shrub productivity increased by 67%. This pattern was explained by different nonlinear responses to precipitation. Grass productivity presented a saturating response to precipitation where dry years had a larger negative effect than the positive effects of wet years. In contrast, shrubs showed an increasing response to precipitation that resulted in an increase in average productivity with increasing precipitation variability. In addition, the effects of precipitation variation increased through time. We argue that the differential responses of grasses and shrubs to precipitation variability and the amplification of this phenomenon through time result from contrasting root distributions of grasses and shrubs and competitive interactions among plant types, confirmed by structural equation analysis. Under drought conditions, grasses reduce their abundance and their ability to absorb water that then is transferred to deep soil layers that are exclusively explored by shrubs. Our work addresses an understudied dimension of climate change that might lead to widespread shrub encroachment reducing the provisioning of ecosystem services to society. PMID:26417095

  7. Few multiyear precipitation-reduction experiments find a shift in the productivity-precipitation relationship

    USDA-ARS?s Scientific Manuscript database

    Precipitation is a key driver of ecosystem net primary productivity and carbon cycling. Global warming is altering precipitation patterns globally, and longer and more intense drought episodes are projected for many temperate and Mediterranean regions. The challenge of predicting the effects of alt...

  8. SEPARATION OF FISSION PRODUCTS FROM PLUTONIUM BY PRECIPITATION

    DOEpatents

    Seaborg, G.T.; Thompson, S.G.; Davidson, N.R.

    1959-09-01

    Fission product separation from hexavalent plutonium by bismuth phosphate precipitation of the fission products is described. The precipitation, according to this invention, is improved by coprecipitating ceric and zirconium phosphates (0.05 to 2.5 grams/liter) with the bismuth phosphate.

  9. Understanding Oceanic Heavy Precipitation Using Scatterometer, Satellite Precipitation, and Reanalysis Products

    NASA Technical Reports Server (NTRS)

    Garg, Piyush; Nesbitt, Stephen W.; Lang, Timothy J.; Chronis, Themis

    2016-01-01

    The primary aim of this study is to understand the heavy precipitation events over Oceanic regions using vector wind retrievals from space based scatterometers in combination with precipitation products from satellite and model reanalysis products. Heavy precipitation over oceans is a less understood phenomenon and this study tries to fill in the gaps which may lead us to a better understanding of heavy precipitation over oceans. Various phenomenon may lead to intense precipitation viz. MJO (Madden-Julian Oscillation), Extratropical cyclones, MCSs (Mesoscale Convective Systems), that occur inside or outside the tropics and if we can decipher the physical mechanisms behind occurrence of heavy precipitation, then it may lead us to a better understanding of such events which further may help us in building more robust weather and climate models. During a heavy precipitation event, scatterometer wind observations may lead us to understand the governing dynamics behind that event near the surface. We hypothesize that scatterometer winds can observe significant changes in the near-surface circulation and that there are global relationships among these quantities. To the degree to which this hypothesis fails, we will learn about the regional behavior of heavy precipitation-producing systems over the ocean. We use a "precipitation feature" (PF) approach to enable statistical analysis of a large database of raining features.

  10. Global Precipitation Measurement (GPM) Mission: Precipitation Processing System (PPS) GPM Mission Gridded Text Products Provide Surface Precipitation Retrievals

    NASA Technical Reports Server (NTRS)

    Stocker, Erich Franz; Kelley, O.; Kummerow, C.; Huffman, G.; Olson, W.; Kwiatkowski, J.

    2015-01-01

    In February 2015, the Global Precipitation Measurement (GPM) mission core satellite will complete its first year in space. The core satellite carries a conically scanning microwave imager called the GPM Microwave Imager (GMI), which also has 166 GHz and 183 GHz frequency channels. The GPM core satellite also carries a dual frequency radar (DPR) which operates at Ku frequency, similar to the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar, and a new Ka frequency. The precipitation processing system (PPS) is producing swath-based instantaneous precipitation retrievals from GMI, both radars including a dual-frequency product, and a combined GMIDPR precipitation retrieval. These level 2 products are written in the HDF5 format and have many additional parameters beyond surface precipitation that are organized into appropriate groups. While these retrieval algorithms were developed prior to launch and are not optimal, these algorithms are producing very creditable retrievals. It is appropriate for a wide group of users to have access to the GPM retrievals. However, for researchers requiring only surface precipitation, these L2 swath products can appear to be very intimidating and they certainly do contain many more variables than the average researcher needs. Some researchers desire only surface retrievals stored in a simple easily accessible format. In response, PPS has begun to produce gridded text based products that contain just the most widely used variables for each instrument (surface rainfall rate, fraction liquid, fraction convective) in a single line for each grid box that contains one or more observations.This paper will describe the gridded data products that are being produced and provide an overview of their content. Currently two types of gridded products are being produced: (1) surface precipitation retrievals from the core satellite instruments GMI, DPR, and combined GMIDPR (2) surface precipitation retrievals for the partner constellation

  11. Precipitation Downscaling Products for Hydrologic Applications (Invited)

    NASA Astrophysics Data System (ADS)

    Gutmann, E. D.; Pruitt, T.; Liu, C.; Clark, M. P.; Brekke, L. D.; Arnold, J.; Raff, D. A.; Rasmussen, R.

    2013-12-01

    Hydrologists and engineers require climate data on high-resolution grids (4-12km) for many water resources applications. To get such data from climate models, users have traditionally relied on statistical downscaling techniques, with only limited use of dynamic downscaling techniques. Statistical techniques utilize a variety of assumptions, data, and methodologies that result in statistical artifacts that may impact hydroclimate representations. These impacts are often pronounced when downscaling precipitation. We will discuss four major statistical downscaling techniques: Bias Corrected Constructed Analogue (BCCA), Asynchronous Regression (AR), and two forms of Bias Corrected Spatial Disaggregation (BCSD.) The hydroclimate representations within many statistical methods often have too much drizzle, too small extreme events, and an improper representation of spatial scaling characteristics. These scaling problems lead some statistical methods substantially over estimate extreme events at hydrologically important scales (e.g., basin totals.) This can lead to large errors in future hydrologic predictions. In contrast, high-resolution dynamic downscaling using the Weather Research and Forecasting model (WRF) provides a better representation of precipitation in many respects, but at a much higher computational cost. This computational constraint prevents the use of high-resolution WRF simulations when examining the range of possible future scenarios generated as part of the Coupled Model Intercomparison Project (CMIP.) Finally, we will present a next generation psuedo-dynamical model that provides dynamic downscaling information for a fraction of the computational requirements. This simple weather model uses large scale circulation patterns from a GCM, for example wind, temperature and humidity, but performs advection and microphysical calculations on a high-resolution grid, thus permitting topography to be adequately represented. This model is capable of generating

  12. Evaluation of Satellite Quantitative Precipitation Estimates (QPEs) Products

    NASA Astrophysics Data System (ADS)

    Prat, O. P.; Nelson, B. R.

    2016-12-01

    In this work, we conduct a long-term assessment of the different Satellite based precipitation products from the Reference Environmental Data Records (PERSIANN-CDR; GPCP; CMORPH-CDR) and from the PMM/GPM suite of products (TMPA, TMPA-RT, IMERG). PERSIANN-CDR is a 30-year record of daily-adjusted global precipitation. GPCP is an approximately 30-year record of monthly and pentad adjusted global precipitation and 17-year record of daily-adjusted global precipitation. CMORPH-CDR is a 17-year record of daily and sub-daily adjusted global precipitation. The products inter-comparisons are performed at various temporal and spatial scales over the concurrent period of record. The evaluation of the different products will include trend analysis and comparison with in-situ data sets from the Global Historical Climatology Network (GHCN-Daily). In addition, we will compare the datasets ability to capture global precipitation patterns and local extreme precipitation events in order to derive a detailed picture of each product strengths and weaknesses.

  13. Extreme precipitation patterns reduced terrestrial ecosystem production across biomes

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Moran, S. M.; Nearing, M.; Ponce Campos, G. E.; Huete, A. R.; Buda, A. R.; Bosch, D. D.; Gunter, S. A.; Kitchen, S. G.; McNab, W.; Morgan, J. A.; McClaran, M. P.; Montoya, D. S.; Peters, D. P.; Starks, P. J.

    2012-12-01

    Precipitation regimes are predicted to shift to more extreme patterns that are characterized by more intense rainfall events and longer dry intervals, yet their ecological impacts on vegetation production remain uncertain across biomes in natural climatic conditions. This in situ study investigated the effects of novel climatic conditions on aboveground net primary production (ANPP) by combining a greenness index from satellite measurements and climatic records during 2000 to 2009 from 11 long-term experimental sites in multiple biomes and climates. Results showed that extreme precipitation patterns decreased the sensitivity of ANPP to total annual precipitation (PT), at the regional and decadal scales, leading to a mean 20% decrease in rain-use efficiency across biomes. Relative decreases in ANPP were greatest for arid grassland (16%) and Mediterranean forest (20%), and less for mesic grassland and temperate forest (3%). The co-occurrence of more heavy rainfall events and longer dry intervals caused greater water stress that resulted in reduced vegetation production. A new generalized model was developed to improve predictions of the ANPP response to changes in extreme precipitation patterns by using a function of both PT and an index of precipitation extremes. These findings suggest that extreme precipitation patterns have more substantial and complex effects on vegetation production across biomes, and are as important as total annual precipitation in understanding vegetation processes. With predictions of more extreme weather events, forecasts of ecosystem production should consider these non-linear responses to altered precipitation patterns associated with climate change. Figure. Relation of production across precipitation gradients for 11 sites for two groups (Low: R95p% < 20%, High: R95p% ≥ 20%). See Table 2 for R95p% definitions. The relations were significantly different for the two groups (F2, 106 = 18.51, P < 0.0001).

  14. Performance of high-resolution satellite precipitation products over China

    NASA Astrophysics Data System (ADS)

    Shen, Yan; Xiong, Anyuan; Wang, Ying; Xie, Pingping

    2010-01-01

    A gauge-based analysis of hourly precipitation is constructed on a 0.25° latitude/longitude grid over China for a 3 year period from 2005 to 2007 by interpolating gauge reports from ˜2000 stations collected and quality controlled by the National Meteorological Information Center of the China Meteorological Administration. Gauge-based precipitation analysis is applied to examine the performance of six high-resolution satellite precipitation estimates, including Joyce et al.'s (2004) Climate Prediction Center Morphing Technique (CMORPH) and the arithmetic mean of the microwave estimates used in CMORPH; Huffman et al.'s (2007) Tropical Rainfall Measuring Mission (TRMM) precipitation product 3B42 and its real-time version 3B42RT; Turk et al.'s (2004) Naval Research Laboratory blended product; and Hsu et al.'s (1997) Precipitation Estimation From Remotely Sensed Information Using Artificial Neural Network (PERSIANN). Our results showed the following: (1) all six satellite products are capable of capturing the overall spatial distribution and temporal variations of precipitation reasonably well; (2) performance of the satellite products varies for different regions and different precipitation regimes, with better comparison statistics observed over wet regions and for warm seasons; (3) products based solely on satellite observations present regionally and seasonally varying biases, while the gauge-adjustment procedures applied in TRMM 3B42 remove the large-scale bias almost completely; (4) CMORPH exhibits the best performance in depicting the spatial pattern and temporal variations of precipitation; and (5) both the relative magnitude and the phase of the warm season precipitation over China are estimated quite well, but the early morning peak associated with the Mei-Yu rainfall over central eastern China is substantially under-estimated by all satellite products.

  15. Performance of high-resolution satellite precipitation products over China

    NASA Astrophysics Data System (ADS)

    Shen, Y.; Xiong, A.; Wang, Y.; Xie, P.; Precipitation Merge Team

    2010-12-01

    A gauge-based analysis of hourly precipitation is constructed on a 0.25°latitude/ longitude grid over China for a 3 year period from 2005 to 2007 by interpolating gauge reports from ~2000 stations (fig.1) collected and quality controlled by the National Meteorological Information Center of the China Meteorological Administration. Gauge-based precipitation analysis is applied to examine the performance of six high-resolution satellite precipitation estimates, including Joyce et al.’s (2004) Climate Prediction Center Morphing Technique (CMORPH) and the arithmetic mean of the microwave estimates used in CMORPH; Huffman et al.’s (2007) Tropical Rainfall Measuring Mission (TRMM) precipitation product 3B42 and its real-time version 3B42RT; Turk et al.’s (2004) Naval Research Laboratory blended product; and Hsu et al.’s (1997) Precipitation Estimation From Remotely Sensed Information Using Artificial Neural Network (PERSIANN). Our results showed the following: (1) all six satellite products are capable of capturing the overall spatial distribution and temporal variations of precipitation reasonably well; (2) performance of the satellite products varies for different regions and different precipitation regimes, with better comparison statistics observed over wet regions and for warm seasons; (3) products based solely on satellite observations present regionally and seasonally varying biases, while the gauge-adjustment procedures applied in TRMM 3B42 remove the large-scale bias almost completely; (4) CMORPH exhibits the best performance in depicting the spatial pattern and temporal variations of precipitation; and (5) both the relative magnitude and the phase of the warm season precipitation over China are estimated quite well, but the early morning peak associated with the Mei-Yu rainfall over central eastern China is substantially under-estimated by all satellite products. The work reported in this paper is an integral part of our efforts to construct an analysis

  16. Assessment of the Consistency among Precipitation Products over Arid Regions

    NASA Astrophysics Data System (ADS)

    Ghebreyesus, Dawit; Temimi, Marouane

    2016-04-01

    This study addresses the analysis of the consistency among global precipitation products over arid regions. First, precipitation products were examined against in situ observations from the UAE network. Then, the consistency among the different products was assessed regionally over the Arabian Peninsula and the Sahara Desert. Four distinct independently-derived precipitation products, namely, Global Precipitation Climate Center (GPCC), Willmott-Matsuura 2001 (WM), Tropical Rainfall Measurement Mission (TRMM), and CPC Morphing (CMORPH) were examined. Over the UAE, in situ monthly observations from 6 stations over a time period of 11 years, from 2000 to 2010 inclusive, were used. The correlation with in situ observations, Root Mean Square Error (RMSE), and Relative Bias (rBIAS) were calculated to evaluate the precipitation products. The lowest areal averaged RMSE over all stations, ranging from 3.82mm to 9.98mm, was obtained with the GPCC indicating a higher agreement with in situ observations. The average RMSE of GPCC over the country was 6.18mm. However, the highest areal averaged RMSE, ranging from 9.44 to 19.52mm, was obtained with the WM product with average of 13.57mm. The results showed an overestimation of the observed rainfall values across all products with overall average of 42%. CMORPH product was found to be the most inconsistent products spatially across the UAE with rBIAS ranging from -47% in Al Ain to 372% in Dubai. The correlation with in situ observations was found to be higher with GPCC product ranging from 0.8450 to 0.9494. TRMM was second with an average of 0.8413, ranging from 0.7098 to 0.9248. Furthermore, Mean Relative Difference (MRD) was calculated to investigate the precision among the precipitation products. CMORPH was found to be inconsistent spatially being the lowest estimator for four stations (Adu Dhabi, Al Ain, Sharjah, Ras Al Khaimah) whereas being the highest estimator for the rest two stations (Dubai and Fujairah). Generally, the

  17. GPM Mission Gridded Text Products Providing Surface Precipitation Retrievals

    NASA Astrophysics Data System (ADS)

    Stocker, Erich Franz; Kelley, Owen; Huffman, George; Kummerow, Christian

    2015-04-01

    In February 2015, the Global Precipitation Measurement (GPM) mission core satellite will complete its first year in space. The core satellite carries a conically scanning microwave imager called the GPM Microwave Imager (GMI), which also has 166 GHz and 183 GHz frequency channels. The GPM core satellite also carries a dual frequency radar (DPR) which operates at Ku frequency, similar to the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar), and a new Ka frequency. The precipitation processing system (PPS) is producing swath-based instantaneous precipitation retrievals from GMI, both radars including a dual-frequency product, and a combined GMI/DPR precipitation retrieval. These level 2 products are written in the HDF5 format and have many additional parameters beyond surface precipitation that are organized into appropriate groups. While these retrieval algorithms were developed prior to launch and are not optimal, these algorithms are producing very creditable retrievals. It is appropriate for a wide group of users to have access to the GPM retrievals. However, for reseachers requiring only surface precipitation, these L2 swath products can appear to be very intimidating and they certainly do contain many more variables than the average researcher needs. Some researchers desire only surface retrievals stored in a simple easily accessible format. In response, PPS has begun to produce gridded text based products that contain just the most widely used variables for each instrument (surface rainfall rate, fraction liquid, fraction convective) in a single line for each grid box that contains one or more observations. This paper will describe the gridded data products that are being produced and provide an overview of their content. Currently two types of gridded products are being produced: (1) surface precipitation retrievals from the core satellite instruments - GMI, DPR, and combined GMI/DPR (2) surface precipitation retrievals for the partner

  18. Are satellite products good proxies for gauge precipitation over Singapore?

    NASA Astrophysics Data System (ADS)

    Hur, Jina; Raghavan, Srivatsan V.; Nguyen, Ngoc Son; Liong, Shie-Yui

    2017-04-01

    The uncertainties in two high-resolution satellite precipitation products (TRMM 3B42 v7.0 and GSMaP v5.222) were investigated by comparing them against rain gauge observations over Singapore on sub-daily scales. The satellite-borne precipitation products are assessed in terms of seasonal, monthly and daily variations, the diurnal cycle, and extreme precipitation over a 10-year period (2000-2010). Results indicate that the uncertainties in extreme precipitation is higher in GSMaP than in TRMM, possibly due to the issues such as satellite merging algorithm, the finer spatio-temporal scale of high intensity precipitation, and the swath time of satellite. Such discrepancies between satellite-borne and gauge-based precipitations at sub-daily scale can possibly lead to distorting analysis of precipitation characteristics and/or application model results. Overall, both satellite products are unable to capture the observed extremes and provide a good agreement with observations only at coarse time scales. Also, the satellite products agree well on the late afternoon maximum and heavier rainfall of gauge-based data in winter season when the Intertropical Convergence Zone (ITCZ) is located over Singapore. However, they do not reproduce the gauge-observed diurnal cycle in summer. The disagreement in summer could be attributed to the dominant satellite overpass time (about 14:00 SGT) later than the diurnal peak time (about 09:00 SGT) of gauge precipitation. From the analyses of extreme precipitation indices, it is inferred that both satellite datasets tend to overestimate the light rain and frequency but underestimate high intensity precipitation and the length of dry spells. This study on quantification of their uncertainty is useful in many aspects especially that these satellite products stand scrutiny over places where there are no good ground data to be compared against. This has serious implications on climate studies as in model evaluations and in particular, climate

  19. Intercomparison of Global Precipitation Products: The Third Precipitation Intercomparison Project (PIP-3)

    NASA Technical Reports Server (NTRS)

    Adler, Robert F.; Kidd, Christopher; Petty, Grant; Morrissey, Mark; Goodman, H. Michael; Einaudi, Franco (Technical Monitor)

    2000-01-01

    A set of global, monthly rainfall products has been intercompared to understand the quality and utility of the estimates. The products include 25 observational (satellite-based), four model and two climatological products. The results of the intercomparison indicate a very large range (factor of two or three) of values when all products are considered. The range of values is reduced considerably when the set of observational products is limited to those considered quasi-standard. The model products do significantly poorer in the tropics, but are competitive with satellite-based fields in mid-latitudes over land. Over ocean, products are compared to frequency of precipitation from ship observations. The evaluation of the observational products point to merged data products (including rain gauge information) as providing the overall best results.

  20. Assessment of Satellite Precipitation Products in the Philippine Archipelago

    NASA Astrophysics Data System (ADS)

    Ramos, M. D.; Tendencia, E.; Espana, K.; Sabido, J.; Bagtasa, G.

    2016-06-01

    Precipitation is the most important weather parameter in the Philippines. Made up of more than 7100 islands, the Philippine archipelago is an agricultural country that depends on rain-fed crops. Located in the western rim of the North West Pacific Ocean, this tropical island country is very vulnerable to tropical cyclones that lead to severe flooding events. Recently, satellite-based precipitation estimates have improved significantly and can serve as alternatives to ground-based observations. These data can be used to fill data gaps not only for climatic studies, but can also be utilized for disaster risk reduction and management activities. This study characterized the statistical errors of daily precipitation from four satellite-based rainfall products from (1) the Tropical Rainfall Measuring Mission (TRMM), (2) the CPC Morphing technique (CMORPH) of NOAA and (3) the Global Satellite Mapping of Precipitation (GSMAP) and (4) Precipitation Estimation from Remotely Sensed information using Artificial Neural Networks (PERSIANN). Precipitation data were compared to 52 synoptic weather stations located all over the Philippines. Results show GSMAP to have over all lower bias and CMORPH with lowest Mean Absolute Error (MAE) and Root Mean Square Error (RMSE). In addition, a dichotomous rainfall test reveals GSMAP and CMORPH have low Proportion Correct (PC) for convective and stratiform rainclouds, respectively. TRMM consistently showed high PC for almost all raincloud types. Moreover, all four satellite precipitation showed high Correct Negatives (CN) values for the north-western part of the country during the North-East monsoon and spring monsoonal transition periods.

  1. TRMM .25 deg x .25 deg Gridded Precipitation Text Product

    NASA Technical Reports Server (NTRS)

    Stocker, Erich; Kelley, Owen

    2009-01-01

    Since the launch of the Tropical Rainfall Measuring Mission (TRMM), the Precipitation Measurement Missions science team has endeavored to provide TRMM precipitation retrievals in a variety of formats that are more easily usable by the broad science community than the standard Hierarchical Data Format (HDF) in which TRMM data is produced and archived. At the request of users, the Precipitation Processing System (PPS) has developed a .25 x .25 gridded product in an easily used ASCII text format. The entire TRMM mission data has been made available in this format. The paper provides the details of this new precipitation product that is designated with the TRMM designator 3G68.25. The format is packaged into daily files. It provides hourly precipitation information from the TRMM microwave imager (TMI), precipitation radar (PR), and TMI/PR combined rain retrievals. A major advantage of this approach is the inclusion only of rain data, compression when a particular grid has no rain from the PR or combined, and its direct ASCII text format. For those interested only in rain retrievals and whether rain is convection or stratiform, these products provide a huge reduction in the data volume inherent in the standard TRMM products. This paper provides examples of the 3G68 data products and their uses. It also provides information about C tools that can be used to aggregate daily files into larger time samples. In addition, it describes the possibilities inherent in the spatial sampling which allows resampling into coarser spatial sampling. The paper concludes with information about downloading the gridded text data products.

  2. Online Comparison of Precipitation Products during the GPM Era

    NASA Astrophysics Data System (ADS)

    Liu, Z.

    2014-12-01

    During the TRMM era, online services (http://disc.sci.gsfc.nasa.gov/precipitation/tovas) have been developed to facilitate intercomparison of TRMM and other global precipitation products. Through Giovanni TOVAS, users can conduct intercomparison of TMPA 3-hourly, daily and monthly products as well as other TRMM and climatology products in areas of interest without downloading data and software. In this presentation, samples of using the IPWG validation statistics will be presented. In addition, a new method will be presented to reveal the difference between two products at the grid point level over a selected time period, giving local information regarding how the two products perform at such level, compared to the regional approach on the IPWG web site. During the GPM era, the first implementation is to include the GPROF daily and monthly precipitation products in Giovanni TOVAS. For the time being, there are 9 GPROF products for the daily and monthly, respectively. Meanwhile, online services for comparing Level-2 data, such as TRMM TMI, PR and TCI will be prototyped because for multi-sensor products, such as TMPA or IMERG, the capability to compare Level-2 products is needed for further understanding of product differences. Examples of such activity will be presented as well.

  3. Extreme precipitation patterns reduced terrestrial ecosystem production across biomass

    USDA-ARS?s Scientific Manuscript database

    Precipitation regimes are predicted to shift to more extreme patterns that are characterized by more intense rainfall events and longer dry intervals, yet their ecological impacts on vegetation production remain uncertain across biomes in natural climatic conditions. This in situ study investigated ...

  4. Online Assessment of Satellite-Derived Global Precipitation Products

    NASA Technical Reports Server (NTRS)

    Liu, Zhong; Ostrenga, D.; Teng, W.; Kempler, S.

    2012-01-01

    Precipitation is difficult to measure and predict. Each year droughts and floods cause severe property damages and human casualties around the world. Accurate measurement and forecast are important for mitigation and preparedness efforts. Significant progress has been made over the past decade in satellite precipitation product development. In particular, products' spatial and temporal resolutions as well as timely availability have been improved by blended techniques. Their resulting products are widely used in various research and applications. However biases and uncertainties are common among precipitation products and an obstacle exists in quickly gaining knowledge of product quality, biases and behavior at a local or regional scale, namely user defined areas or points of interest. Current online inter-comparison and validation services have not addressed this issue adequately. To address this issue, we have developed a prototype to inter-compare satellite derived daily products in the TRMM Online Visualization and Analysis System (TOVAS). Despite its limited functionality and datasets, users can use this tool to generate customized plots within the United States for 2005. In addition, users can download customized data for further analysis, e.g. comparing their gauge data. To meet increasing demands, we plan to increase the temporal coverage and expanded the spatial coverage from the United States to the globe. More products have been added as well. In this poster, we present two new tools: Inter-comparison of 3B42RT and 3B42 Inter-comparison of V6 and V7 TRMM L-3 monthly products The future plans include integrating IPWG (International Precipitation Working Group) Validation Algorithms/statistics, allowing users to generate customized plots and data. In addition, we will expand the current daily products to monthly and their climatology products. Whenever the TRMM science team changes their product version number, users would like to know the differences by

  5. Utilization of Precipitation and Moisture Products Derived from Satellites to Support NOAA Operational Precipitation Forecasts

    NASA Astrophysics Data System (ADS)

    Ferraro, R.; Zhao, L.; Kuligowski, R. J.; Kusselson, S.; Ma, L.; Kidder, S. Q.; Forsythe, J. M.; Jones, A. S.; Ebert, E. E.; Valenti, E.

    2012-12-01

    NOAA/NESDIS operates a constellation of polar and geostationary orbiting satellites to support weather forecasts and to monitor the climate. Additionally, NOAA utilizes satellite assets from other U.S. agencies like NASA and the Department of Defense, as well as those from other nations with similar weather and climate responsibilities (i.e., EUMETSAT and JMA). Over the past two decades, through joint efforts between U.S. and international government researchers, academic partners, and private sector corporations, a series of "value added" products have been developed to better serve the needs of weather forecasters and to exploit the full potential of precipitation and moisture products generated from these satellites. In this presentation, we will focus on two of these products - Ensemble Tropical Rainfall Potential (eTRaP) and Blended Total Precipitable Water (bTPW) - and provide examples on how they contribute to hydrometeorological forecasts. In terms of passive microwave satellite products, TPW perhaps is most widely used to support real-time forecasting applications, as it accurately depicts tropospheric water vapor and its movement. In particular, it has proven to be extremely useful in determining the location, timing, and duration of "atmospheric rivers" which contribute to and sustain flooding events. A multi-sensor approach has been developed and implemented at NESDIS in which passive microwave estimates from multiple satellites and sensors are merged to create a seamless, bTPW product that is more efficient for forecasters to use. Additionally, this product is being enhanced for utilization for television weather forecasters. Examples will be shown to illustrate the roll of atmospheric rivers and contribution to flooding events, and how the bTPW product was used to improve the forecast of these events. Heavy rains associated with land falling tropical cyclones (TC) frequently trigger floods that cause millions of dollars of damage and tremendous loss

  6. Evaluating GPM Precipitation Products in Real-Time

    NASA Astrophysics Data System (ADS)

    Kirstetter, P.; Hong, Y.; Gourley, J. J.; Cao, Q.; Zhang, J.; Chen, S.; Petersen, W. A.; Schwaller, M.; Anagnostou, E. N.

    2013-12-01

    This presentation introduces a webpage that will compare GPM precipitation estimates to the NEXRAD-based precipitation estimates derived from NOAA/NSSL's Multi-Radar, Multisensor (MRMS) platform in real-time. The MRMS products, after having been adjusted by rain gauges and passing several quality control and filtering procedures, have been used by a number of NASA investigators to evaluate level II and level III TMPA rainfall algorithms. Statistics from TMPA will thus serve as a benchmark to evaluate forthcoming GPM precipitation estimates. The NEXRAD network has also undergone an upgrade in technology with dual-polarization capabilities. These new polarimetric variables are being incorporated in MRMS to improve quality control of reflectivity data and to correct for partial beam blockages. The same logic employed for precipitation estimation without polarization diversity is being used in the latest MRMS algorithm version, thus the reference precipitation is stable during the transition from the TMPA to GPM era. We will also introduce recent developments in the derivation of probability distributions of rainfall rates instead of single values using a model quantifying the relation between radar reflectivity and the corresponding 'true' rainfall. Ensembles of reflectivity-to-rain rate relationships accounting explicitly for rain typology are derived for ground and space radars. This approach preserves the fine space/time sampling properties of the radar and conditions probabilistic QPE (PQPE) on the rain rate and rainfall type.

  7. Utilizing Satellite-derived Precipitation Products in Hydrometeorological Applications

    NASA Astrophysics Data System (ADS)

    Liu, Z.; Ostrenga, D.; Teng, W. L.; Kempler, S. J.; Huffman, G. J.

    2012-12-01

    Each year droughts and floods happen around the world and can cause severe property damages and human casualties. Accurate measurement and forecast are important for preparedness and mitigation efforts. Through multi-satellite blended techniques, significant progress has been made over the past decade in satellite-based precipitation product development, such as, products' spatial and temporal resolutions as well as timely availability. These new products are widely used in various research and applications. In particular, the TRMM Multi-satellite Precipitation Analysis (TMPA) products archived and distributed by the NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC) provide 3-hourly, daily and monthly near-global (50° N - 50° S) precipitation datasets for research and applications. Two versions of TMPA products are available, research (3B42, 3B43, rain gauge adjusted) and near-real-time (3B42RT). At GES DISC, we have developed precipitation data services to support hydrometeorological applications in order to maximize the TRMM mission's societal benefits. In this presentation, we will present examples of utilizing TMPA precipitation products in hydrometeorological applications including: 1) monitoring global floods and droughts; 2) providing data services to support the USDA Crop Explorer; 3) support hurricane monitoring activities and research; and 4) retrospective analog year analyses to improve USDA's world agricultural supply and demand estimates. We will also present precipitation data services that can be used to support hydrometeorological applications including: 1) User friendly TRMM Online Visualization and Analysis System (TOVAS; URL: http://disc2.nascom.nasa.gov/Giovanni/tovas/); 2) Mirador (http://mirador.gsfc.nasa.gov/), a simplified interface for searching, browsing, and ordering Earth science data at GES DISC; 3) Simple Subset Wizard (http://disc.sci.gsfc.nasa.gov/SSW/ ) for data subsetting and format conversion; 4) Data

  8. Few multiyear precipitation-reduction experiments find a shift in the productivity-precipitation relationship.

    PubMed

    Estiarte, Marc; Vicca, Sara; Peñuelas, Josep; Bahn, Michael; Beier, Claus; Emmett, Bridget A; Fay, Philip A; Hanson, Paul J; Hasibeder, Roland; Kigel, Jaime; Kröel-Dulay, Gyorgy; Larsen, Klaus Steenberg; Lellei-Kovács, Eszter; Limousin, Jean-Marc; Ogaya, Romà; Ourcival, Jean-Marc; Reinsch, Sabine; Sala, Osvaldo E; Schmidt, Inger Kappel; Sternberg, Marcelo; Tielbörger, Katja; Tietema, Albert; Janssens, Ivan A

    2016-07-01

    Well-defined productivity-precipitation relationships of ecosystems are needed as benchmarks for the validation of land models used for future projections. The productivity-precipitation relationship may be studied in two ways: the spatial approach relates differences in productivity to those in precipitation among sites along a precipitation gradient (the spatial fit, with a steeper slope); the temporal approach relates interannual productivity changes to variation in precipitation within sites (the temporal fits, with flatter slopes). Precipitation-reduction experiments in natural ecosystems represent a complement to the fits, because they can reduce precipitation below the natural range and are thus well suited to study potential effects of climate drying. Here, we analyse the effects of dry treatments in eleven multiyear precipitation-manipulation experiments, focusing on changes in the temporal fit. We expected that structural changes in the dry treatments would occur in some experiments, thereby reducing the intercept of the temporal fit and displacing the productivity-precipitation relationship downward the spatial fit. The majority of experiments (72%) showed that dry treatments did not alter the temporal fit. This implies that current temporal fits are to be preferred over the spatial fit to benchmark land-model projections of productivity under future climate within the precipitation ranges covered by the experiments. Moreover, in two experiments, the intercept of the temporal fit unexpectedly increased due to mechanisms that reduced either water loss or nutrient loss. The expected decrease of the intercept was observed in only one experiment, and only when distinguishing between the late and the early phases of the experiment. This implies that we currently do not know at which precipitation-reduction level or at which experimental duration structural changes will start to alter ecosystem productivity. Our study highlights the need for experiments with

  9. Physically-based, Hydrologic Simulations Driven by Three Precipitation Products

    NASA Astrophysics Data System (ADS)

    Chintalapudi, S.; Sharif, H. O.; Yeggina, S.; El Hassan, A.

    2011-12-01

    This study evaluates the model-simulated stream discharge over the Guadalupe River basin in central Texas driven by three precipitation products: the Guadalupe-Blanco River Authority (GBRA) rain gauge network, the Next Generation Weather Radar (NEXRAD) Stage ΙΙΙ precipitation product, and the Tropical Rainfall Measurement Mission (TRMM) 3B42 product. Focus will be on results from the Upper Guadalupe River sub-basin. This sub-basin is more prone to flooding due to its geological properties (thin soils, exposed bedrock, and sparse vegetation) and the impact of Balcones Escarpment on the moisture coming from the Gulf of Mexico. The physically based, distributed-parameter Gridded Surface Subsurface Hydrologic Analysis (GSSHA) hydrologic model was used to simulate the June-2002 flooding event. Simulations driven by NEXRAD Stage ΙΙΙ 15 - min precipitation yielded better results with low RMSE (88.3%), high NSE (0.6), high R2 (0.73), low RSR (0.63) and low PBIAS (-17.3%) compared to simulations driven by the other products.

  10. Enhanced interannual precipitation variability increases plant functional diversity that in turn ameliorates negative impact on productivity.

    PubMed

    Gherardi, Laureano A; Sala, Osvaldo E

    2015-12-01

    Although precipitation interannual variability is projected to increase due to climate change, effects of changes in precipitation variance have received considerable less attention than effects of changes in the mean state of climate. Interannual precipitation variability effects on functional diversity and its consequences for ecosystem functioning are assessed here using a 6-year rainfall manipulation experiment. Five precipitation treatments were switched annually resulting in increased levels of precipitation variability while maintaining average precipitation constant. Functional diversity showed a positive response to increased variability due to increased evenness. Dominant grasses decreased and rare plant functional types increased in abundance because grasses showed a hump-shaped response to precipitation with a maximum around modal precipitation, whereas rare species peaked at high precipitation values. Increased functional diversity ameliorated negative effects of precipitation variability on primary production. Rare species buffered the effect of precipitation variability on the variability in total productivity because their variance decreases with increasing precipitation variance.

  11. Temporal Analysis of Remotely Sensed Precipitation Products for Hydrological Applications

    NASA Astrophysics Data System (ADS)

    Tobin, K. J.; Bennett, M. E.

    2011-12-01

    No study has systematically evaluated streamflow modeling between monthly and daily timescales. This study examines streamflow from eight watersheds across the United States where five different precipitation products were used as primary input into the Soil and Water Assessment Tool to generate simulated streamflow. Timescales examined include monthly, dekad (10 day), pentad (5 day), triad (3 day), and daily. The eight basins studied are the San Pedro (Arizona); Cimarron (north-central Oklahoma); mid-Nueces (south Texas); mid-Rio Grande (south Texas and northern Mexico), Yocano (northern Mississippi); Alapaha (south Georgia); Upper Tar (North Carolina) and mid-St. Francis (eastern Arkansas). The precipitation products used to drive simulations include rain gauge, NWS Multisensor Precipitation Estimator, Tropical Rainfall Measurement Mission, Multi-Satellite (TRMM) Precipitation Analysis, TRMM 3B42-V6, and Climate Prediction Center Morphing Method (CMORPH). Understanding how streamflow varies at sub-monthly timescales is important because there are a host of hydrological applications such a flood forecast guidance and reservoir inflow forecasts that reside in a temporal domain between monthly and daily timescales. The major finding of this study is the quantification of a strong positive correlation between performance metrics and time step at which model performance deteriorates. Basically, better performing simulations, with higher Nash-Sutcliffe values of 0.80 and above can support modeling at finer timescales to at least daily and perhaps beyond into the sub-daily realm. These findings are significant in that they clearly document the ability of SWAT to support modeling at sub-monthly time steps, which is beyond the capability for which SWAT was initially designed.

  12. Improving high-resolution quantitative precipitation estimation via fusion of multiple radar-based precipitation products

    NASA Astrophysics Data System (ADS)

    Rafieeinasab, Arezoo; Norouzi, Amir; Seo, Dong-Jun; Nelson, Brian

    2015-12-01

    For monitoring and prediction of water-related hazards in urban areas such as flash flooding, high-resolution hydrologic and hydraulic modeling is necessary. Because of large sensitivity and scale dependence of rainfall-runoff models to errors in quantitative precipitation estimates (QPE), it is very important that the accuracy of QPE be improved in high-resolution hydrologic modeling to the greatest extent possible. With the availability of multiple radar-based precipitation products in many areas, one may now consider fusing them to produce more accurate high-resolution QPE for a wide spectrum of applications. In this work, we formulate and comparatively evaluate four relatively simple procedures for such fusion based on Fisher estimation and its conditional bias-penalized variant: Direct Estimation (DE), Bias Correction (BC), Reduced-Dimension Bias Correction (RBC) and Simple Estimation (SE). They are applied to fuse the Multisensor Precipitation Estimator (MPE) and radar-only Next Generation QPE (Q2) products at the 15-min 1-km resolution (Experiment 1), and the MPE and Collaborative Adaptive Sensing of the Atmosphere (CASA) QPE products at the 15-min 500-m resolution (Experiment 2). The resulting fused estimates are evaluated using the 15-min rain gauge observations from the City of Grand Prairie in the Dallas-Fort Worth Metroplex (DFW) in north Texas. The main criterion used for evaluation is that the fused QPE improves over the ingredient QPEs at their native spatial resolutions, and that, at the higher resolution, the fused QPE improves not only over the ingredient higher-resolution QPE but also over the ingredient lower-resolution QPE trivially disaggregated using the ingredient high-resolution QPE. All four procedures assume that the ingredient QPEs are unbiased, which is not likely to hold true in reality even if real-time bias correction is in operation. To test robustness under more realistic conditions, the fusion procedures were evaluated with and

  13. Effects of alteration product precipitation on glass dissolution

    SciTech Connect

    Strachan, Denis M.; Neeway, James J.

    2014-06-01

    Understanding the mechanisms that control the durability of nuclear waste glass is paramount if reliable models are to be constructed so that the glass dissolution rate in a given geological repository can be calculated. Presently, it is agreed that (boro)silicate glasses dissolve in water at a rate dependent on the solution concentration of orthosilicic acid (H4SiO4) with higher [H4SiO4] leading to lower dissolution rates. Once the reaction has slowed as a result of the buildup of H4SiO4, another increase in the rate has been observed that corresponds to the precipitation of certain silica-bearing alteration products. However, it has also been observed that the concentration of silica-bearing solution species does not significantly decrease, indicating saturation, while other glass tracer elements concentrations continue to increase, indicating that the glass is still dissolving. In this study, we have used the Geochemist’s Workbench code to investigate the relationship between glass dissolution rates and the precipitation rate of a representative zeolitic silica-bearing alteration product, analcime [Na(AlSi2O6)∙H2O]. To simplify the calculations, we suppressed all alteration products except analcime, gibbsite (Al(OH)3), and amorphous silica. The pseudo-equilibrium-constant matrix for amorphous silica was substituted for the glass pseudo-equilibrium-constant matrix because it has been shown that silicate glasses act as a silica-only solid with respect to kinetic considerations. In this article, we present the results of our calculations of the glass dissolution rate at different values for the analcime precipitation rate constant and the effects of varying the glass dissolution rate constant at a constant analcime precipitation rate constant. From the simulations we conclude, firstly, that the rate of glass dissolution is dependent on the kinetics of

  14. Enhanced precipitation variability decreases grass- and increases shrub-productivity

    USDA-ARS?s Scientific Manuscript database

    Although projections of precipitation change indicate increases in variability, most studies of impacts of climate change on ecosystems focused on effects of changes in amount of precipitation, overlooking precipitation variability effects, especially at the interannual scale. Here, we present resul...

  15. Hydrometeorological Studies With NEXRAD-based Precipitation Products

    NASA Astrophysics Data System (ADS)

    Grassotti, C.; Vivoni, E.; Hoffman, R.; Entekhabi, D.

    2002-05-01

    We have been engaged in the development of an integrated hydrometeorologic forecasting system which uses NEXRAD-based rainfall estimates as one of several inputs to a distributed hydrologic model. In the course of this work we have conducted sensitivity tests over several river basins in eastern Oklahoma comparing two widely-available precipitation products, the 4-km resolution Stage III/P1 estimates produced by the National Weather Service Arkansas-Red Basin River Forecast Center (ABRFC), and the 2-km NOWrad precipitation estimates produced by Weather Services International, Inc. (WSI) and their corresponding impact on hydrologic predictions. Preliminary results show forecast sensitivity to such characteristics as basin scale, spatial averaging, and estimated rain rates. One of the objectives of the project is to extend the lead time for useful hydrologic predictions by augmenting the rainfall observations with rainfall forecasts which can then be input to the distributed model. For extremely short-term rainfall forecasting the best approach is one which utilizes recent radar rainfall estimates themselves. Longer-term forecasts of precipitation can potentially be produced by high-resolution mesoscale weather prediction models. In this context, we have implemented an algorithm to produce short-term precipitation forecasts based on an extrapolation of observed features in successive radar rainfall images. The algorithm combines a scale separation method with a feature correlation technique to produce forecasts of rain amounts in the forecast range of approximately 0 to 3 hours. To gain insight into the error characteristics of the radar rainfall estimates we have also conducted a 3-way intercomparison of ABRFC, WSI, and surface rain gauge observations over an 18-month period. While generally similar to one another in terms of daily and hourly accumulations and in spatial depiction of rain areas, some differences exist and these will be reported in the poster.

  16. PURIFICATION OF PLUTONIUM USING A CERIUM PRECIPITATE AS A CARRIER FOR FISSION PRODUCTS

    DOEpatents

    Faris, B.F.; Olson, C.M.

    1961-07-01

    Bismuth phosphate carrier precipitation processes are described for the separation of plutonium from fission products wherein in at least one step bismuth phosphate is precipitated in the presence of hexavalent plutonium thereby carrying a portion of the fission products from soluble plu tonium values. In this step, a cerium phosphate precipitate is formed in conjunction with the bismuth phosphate precipitate, thereby increasing the amount of fission products removed from solution.

  17. Few multi-year precipitation-reduction experiments find a shift in the productivity-precipitation relationship

    DOE PAGES

    Estiarte, Marc; Vicca, Sara; Penuelas, Josep; ...

    2016-04-06

    Well-defined productivity–precipitation relationships of ecosystems are needed as benchmarks for the validation of land models used for future projections. The productivity–precipitation relationship may be studied in two ways: the spatial approach relates differences in productivity to those in precipitation among sites along a precipitation gradient (the spatial fit, with a steeper slope); the temporal approach relates interannual productivity changes to variation in precipitation within sites (the temporal fits, with flatter slopes). Precipitation–reduction experiments in natural ecosystems represent a complement to the fits, because they can reduce precipitation below the natural range and are thus well suited to study potential effectsmore » of climate drying. Here, we analyse the effects of dry treatments in eleven multiyear precipitation–manipulation experiments, focusing on changes in the temporal fit. We expected that structural changes in the dry treatments would occur in some experiments, thereby reducing the intercept of the temporal fit and displacing the productivity–precipitation relationship downward the spatial fit. Seventy two percent of expiriments showed that dry treatments did not alter the temporal fit. This implies that current temporal fits are to be preferred over the spatial fit to benchmark land-model projections of productivity under future climate within the precipitation ranges covered by the experiments. Moreover, in two experiments, the intercept of the temporal fit unexpectedly increased due to mechanisms that reduced either water loss or nutrient loss. The expected decrease of the intercept was observed in only one experiment, and only when distinguishing between the late and the early phases of the experiment. This implies that we currently do not know at which precipitation–reduction level or at which experimental duration structural changes will start to alter ecosystem productivity. Our study highlights the need

  18. Few multi-year precipitation-reduction experiments find a shift in the productivity-precipitation relationship

    SciTech Connect

    Estiarte, Marc; Vicca, Sara; Penuelas, Josep; Bahn, Michael; Beier, Claus; Emmett, Bridget; Fay, Phillip A.; Hanson, Paul J.; Hasibeder, Roland; Kigel, Jaime; Kroel-Dulay, Gyorgy; Larsen, Klaus Steenberg; Lellei-Kovacs, Eszter; Limousin, Jean-Marc; Ogaya, Roma; Ourcival, Jean-Marc; Reinsch, Sabine; Sala, Osvaldo E.; Schmidt, Inger Kappel; Sternberg, Marcelo; Tielborger, Katja; Tietema, Albert; Janssens, Ivan A.

    2016-04-06

    Well-defined productivity–precipitation relationships of ecosystems are needed as benchmarks for the validation of land models used for future projections. The productivity–precipitation relationship may be studied in two ways: the spatial approach relates differences in productivity to those in precipitation among sites along a precipitation gradient (the spatial fit, with a steeper slope); the temporal approach relates interannual productivity changes to variation in precipitation within sites (the temporal fits, with flatter slopes). Precipitation–reduction experiments in natural ecosystems represent a complement to the fits, because they can reduce precipitation below the natural range and are thus well suited to study potential effects of climate drying. Here, we analyse the effects of dry treatments in eleven multiyear precipitation–manipulation experiments, focusing on changes in the temporal fit. We expected that structural changes in the dry treatments would occur in some experiments, thereby reducing the intercept of the temporal fit and displacing the productivity–precipitation relationship downward the spatial fit. Seventy two percent of expiriments showed that dry treatments did not alter the temporal fit. This implies that current temporal fits are to be preferred over the spatial fit to benchmark land-model projections of productivity under future climate within the precipitation ranges covered by the experiments. Moreover, in two experiments, the intercept of the temporal fit unexpectedly increased due to mechanisms that reduced either water loss or nutrient loss. The expected decrease of the intercept was observed in only one experiment, and only when distinguishing between the late and the early phases of the experiment. This implies that we currently do not know at which precipitation–reduction level or at which experimental duration structural changes will start to alter ecosystem productivity. Our study highlights the need for

  19. An application programming interface for extreme precipitation and hazard products

    NASA Astrophysics Data System (ADS)

    Kirschbaum, D.; Stanley, T.; Cappelaere, P. G.; Reed, J.; Lammers, M.

    2016-12-01

    Remote sensing data provides situational awareness of extreme events and hazards over large areas in a way that is impossible to achieve with in situ data. However, more valuable than raw data is actionable information based on user needs. This information can take the form of derived products, extraction of a subset of variables in a larger data matrix, or data processing for a specific goal. These products can then stream to the end users, who can use these data to improve local to global decision making. This presentation will outline both the science and methodology of two new data products and tools that can provide relevant climate and hazard data for response and support. The Global Precipitation Measurement (GPM) mission provides near real-time information on rain and snow around the world every thirty minutes. Through a new applications programing interface (API), this data can be freely accessed by consumers to visualize, analyze, and communicate where, when and how much rain is falling worldwide. The second tool is a global landslide model that provides situational awareness of potential landslide activity in near real-time, utilizing several remotely sensed data products. This hazard information is also provided through an API and is being ingested by the emergency response community, international aid organizations, and others around the world. This presentation will highlight lessons learned through the development, implementation, and communication of these products and tools with the goal of enabling better and more effective decision making.

  20. Evaluation of the Performance of Satellite Precipitation Products over Africa

    NASA Astrophysics Data System (ADS)

    Merino, M.; Serrat-Capdevila, A.; Valdes, J. B.; Durcik, M.

    2013-05-01

    An analysis of the errors of satellite rainfall estimates over the Africa, in relation to spatial distribution over the continent, as well as their seasonal characteristics, and relation to other spatial features, such as longitude bands, topography and climatic classification is presented. Three near-real time satellite rainfall products, CMORPH, PERSIANN and TMPA-3B42RT, were compared against a ground truth dataset (Sheffield, Goteti, & Wood, 2006) in order to compute the daily residuals of the remote sensed estimates for a grid of 0.25° by 0.25° over Africa. Different analysis were run to extract patterns that relate the residuals to spatial features, such as latitude bands, climatic classification zones, topographic features, and temporal features, such as month or season. Finally, an analysis of how real-time bias corrections methods could be used to improve satellite precipitation estimates over the continent is presented.

  1. Evaluation of global fine-resolution precipitation products and their uncertainty quantification in ensemble discharge simulations

    NASA Astrophysics Data System (ADS)

    Qi, W.; Zhang, C.; Fu, G.; Sweetapple, C.; Zhou, H.

    2016-02-01

    The applicability of six fine-resolution precipitation products, including precipitation radar, infrared, microwave and gauge-based products, using different precipitation computation recipes, is evaluated using statistical and hydrological methods in northeastern China. In addition, a framework quantifying uncertainty contributions of precipitation products, hydrological models, and their interactions to uncertainties in ensemble discharges is proposed. The investigated precipitation products are Tropical Rainfall Measuring Mission (TRMM) products (TRMM3B42 and TRMM3B42RT), Global Land Data Assimilation System (GLDAS)/Noah, Asian Precipitation - Highly-Resolved Observational Data Integration Towards Evaluation of Water Resources (APHRODITE), Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN), and a Global Satellite Mapping of Precipitation (GSMAP-MVK+) product. Two hydrological models of different complexities, i.e. a water and energy budget-based distributed hydrological model and a physically based semi-distributed hydrological model, are employed to investigate the influence of hydrological models on simulated discharges. Results show APHRODITE has high accuracy at a monthly scale compared with other products, and GSMAP-MVK+ shows huge advantage and is better than TRMM3B42 in relative bias (RB), Nash-Sutcliffe coefficient of efficiency (NSE), root mean square error (RMSE), correlation coefficient (CC), false alarm ratio, and critical success index. These findings could be very useful for validation, refinement, and future development of satellite-based products (e.g. NASA Global Precipitation Measurement). Although large uncertainty exists in heavy precipitation, hydrological models contribute most of the uncertainty in extreme discharges. Interactions between precipitation products and hydrological models can have the similar magnitude of contribution to discharge uncertainty as the hydrological models. A

  2. A Generalized Statistical Uncertainty Model for Satellite Precipitation Products

    NASA Astrophysics Data System (ADS)

    Sarachi, S.

    2013-12-01

    A mixture model of Generalized Normal Distribution and Gamma distribution (GND-G) is used to model the joint probability distribution of satellite-based and stage IV radar rainfall under a given spatial and temporal resolution (e.g. 1°x1° and daily rainfall). The distribution parameters of GND-G are extended across various rainfall rates and spatial and temporal resolutions. In the study, GND-G is used to describe the uncertainty of the estimates from Precipitation Estimation from Remote Sensing Information using Artificial Neural Network algorithm (PERSIANN). The stage IV-based multi-sensor precipitation estimates (MPE) are used as reference measurements .The study area for constructing the uncertainty model covers a 15°×15°box of 0.25°×0.25° cells over the eastern United States for summer 2004 to 2009. Cells are aggregated in space and time to obtain data with different resolutions for the construction of the model's parameter space. Result shows that comparing to the other statistical uncertainty models, GND-G fits better than the other models, such as Gaussian and Gamma distributions, to the reference precipitation data. The impact of precipitation uncertainty to the stream flow is further demonstrated by Monte Carlo simulation of precipitation forcing in the hydrologic model. The NWS DMIP2 basins over Illinois River basin south of Siloam is selected in this case study. The data covers the time period of 2006 to 2008.The uncertainty range of stream flow from precipitation of GND-G distributions calculated and will be discussed.

  3. Comparison of satellite precipitation products with Q3 over the CONUS

    NASA Astrophysics Data System (ADS)

    Wang, J.; Petersen, W. A.; Wolff, D. B.; Kirstetter, P. E.

    2016-12-01

    The Global Precipitation Measurement (GPM) is an international satellite mission that provides a new-generation of global precipitation observations. A wealth of precipitation products have been generated since the launch of the GPM Core Observatory in February of 2014. However, the accuracy of the satellite-based precipitation products is affected by discrete temporal sampling and remote spaceborne retrieval algorithms. The GPM Ground Validation (GV) program is currently underway to independently verify the satellite precipitation products, which can be carried out by comparing satellite products with ground measurements. This study compares four Day-1 GPM surface precipitation products derived from the GPM Microwave Imager (GMI), Ku-band Precipitation Radar (KU), Dual-Frequency Precipitation Radar (DPR) and DPR-GMI CoMBined (CMB) algorithms, as well as the near-real-time Integrated Multi-satellitE Retrievals for GPM (IMERG) Late Run product and precipitation retrievals from Microwave Humidity Sounders (MHS) flown on NOAA and METOPS satellites, with the NOAA Multi-Radar Multi-Sensor suite (MRMS; now called "Q3"). The comparisons are conducted over the conterminous United States (CONUS) at various spatial and temporal scales with respect to different precipitation intensities, and filtered with radar quality index (RQI) thresholds and precipitation types. Various versions of GPM products are evaluated against Q3. The latest Version-04A GPM products are in reasonably good overall agreement with Q3. Based on the mission-to-date (March 2014 - May 2016) data from all GPM overpasses, the biases relative to Q3 for GMI and DPR precipitation estimates at 0.5o resolution are negative, whereas the biases for CMB and KU precipitation estimates are positive. Based on all available data (March 2015 - April 2016 at this writing), the CONUS-averaged near-real-time IMERG Late Run hourly precipitation estimate is about 46% higher than Q3. Preliminary comparison of 1-year (2015) MHS

  4. New Global Precipitation Products and Data Service Updates at the NASA GES DISC

    NASA Technical Reports Server (NTRS)

    Liu, Z.; Ostrenga, D.; Savtchenko, A.; DeShong, B.; Greene, M.; Vollmer, B.; Kempler, S.

    2016-01-01

    This poster describes recent updates of the ongoing GPM data service activities at the NASA Goddard Earth Sciences (GES) Data and Information Services Center(DISC) to facilitate access and exploration of GPM, TRMM and other NASA precipitation datasets for the global community. The poster contains -Updates on GPM products and data services -New features in Giovanni for precipitation data visualization -Precipitation data and service outreach activities.

  5. EXPERIMENTAL STUDY OF THE CALCITE PRECIPITATION BASED ON THE UREASE PRODUCTION BACTERIUM ISOLATED FROM PEAT

    NASA Astrophysics Data System (ADS)

    Hata, Toshiro; Sato, Atsuko; Kawasaki, Satoru; Abe, Hirofumi

    In this paper, authors proposed the newly calcite precipitation method for peat. This method can be isolated the urease production bacterium. The main outcomes of this research were: (1) Proposed method can be isolated the urease production bacterium from peat. (2) Urease production bacterium from peat can be accelerate the calcite precipitation at the high pH and high chlorine conditions. (3) Calcite precipitation speed was slower than the B. pasteurii . (4) Proposed method can accelerate the soil strength (Over 400kN/m2 -1D compression test) after 2 week cultivation.

  6. SEPARATION OF FISSION PRODUCT VALUES FROM THE HEXAVALENT PLUTONIUM BY CARRIER PRECIPITATION

    DOEpatents

    Davies, T.H.

    1959-12-15

    An improved precipitation of fission products on bismuth phosphate from an aqueous mineral acid solution also containing hexavalent plutonium by incorporating, prior to bismuth phosphate precipitation, from 0.05 to 2.5 grams/ liter of zirconium phosphate, niobium oxide. and/or lanthanum fluoride is described. The plutonium remains in solution.

  7. Explore GPM IMERG and Other Global Precipitation Products with GES DISC GIOVANNI

    NASA Technical Reports Server (NTRS)

    Liu, Zhong; Ostrenga, Dana M.; Vollmer, Bruce; MacRitchie, Kyle; Kempler, Steven

    2015-01-01

    New features and capabilities in the newly released GIOVANNI allow exploring GPM IMERG (Integrated Multi-satelliE Retrievals for GPM) Early, Late and Final Run global half-hourly and monthly precipitation products as well as other precipitation products distributed by the GES DISC such as TRMM Multi-Satellite Precipitation Analysis (TMPA), MERRA (Modern Era Retrospective-Analysis for Research and Applications), NLDAS (North American Land Data Assimilation Systems), GLDAS (Global Land Data Assimilation Systems), etc. GIOVANNI is a web-based tool developed by the GES DISC (Goddard Earth Sciences and Data Information Services Center) to visualize and analyze Earth science data without having to download data and software. The new interface in GIOVANNI allows searching and filtering precipitation products from different NASA missions and projects and expands the capabilities to inter-compare different precipitation products in one interface. Knowing differences in precipitation products is important to identify issues in retrieval algorithms, biases, uncertainties, etc. Due to different formats, data structures, units and so on, it is not easy to inter-compare precipitation products. Newly added features and capabilities (unit conversion, regridding, etc.) in GIOVANNI make inter-comparisons possible. In this presentation, we will describe these new features and capabilities along with examples.

  8. Explore GPM IMERG and Other Global Precipitation Products with GES DISC GIOVANNI

    NASA Astrophysics Data System (ADS)

    Liu, Z.; Ostrenga, D.; Vollmer, B.; Macritchie, K.; Kempler, S. J.

    2015-12-01

    New features and capabilities in the newly released GIOVANNI allow exploring GPM IMERG (Integrated Multi-satelliE Retrievals for GPM) Early, Late and Final Run global half-hourly and monthly precipitation products as well as other precipitation products distributed by the GES DISC such as TRMM Multi-Satellite Precipitation Analysis (TMPA), MERRA (Modern Era Retrospective-Analysis for Research and Applications), NLDAS (North American Land Data Assimilation Systems), GLDAS (Global Land Data Assimilation Systems), etc. GIOVANNI is a web-based tool developed by the GES DISC (Goddard Earth Sciences and Data Information Services Center), to visualize and analyze Earth science data without having to download data and software. The new interface in GIOVANNI allows searching and filtering precipitation products from different NASA missions and projects and expands the capabilities to inter-compare different precipitation products in one interface. Knowing differences in precipitation products is important to identify issues in retrieval algorithms, biases, uncertainties, etc. Due to different formats, data structures, units and so on, it is not easy to inter-compare these precipitation products. The recently added new features and capabilities (unit conversion, regridding, etc.) in GIOVANNI make inter-comparison possible. In this presentation, we will describe these new feature and capabilities along with examples. (Related URLs: GIOVANNI URL: http://giovanni.gsfc.nasa.gov/giovanni/; GES DISC: http://disc.gsfc.nasa.gov/)

  9. Evaluation of GPM precipitation products using Q3 over the CONUS

    NASA Astrophysics Data System (ADS)

    Wang, J.

    2015-12-01

    Given the one-year-plus, successful operation of the Global Precipitation Measurement (GPM) Mission, it is now possible to provide quantitative evaluation for a new generation of space-borne instrument measurements and retrieved precipitation products using ground-based precipitation observations with greater certainty. This study compares three Day-1 GPM surface precipitation products derived from the GPM Microwave Imager (GMI), Dual-Frequency Precipitation Radar (DPR) and DPR-GMI CoMBined (CMB) algorithms, as well as the near-real-time Integrated Multi-satellitE Retrievals for GPM (IMERG) Late Run product, with the NOAA Multi-Radar Multi-Sensor suite (MRMS; now called "Q3"). The comparisons are conducted over the conterminous United States (CONUS) at various spatial and temporal scales with respect to different precipitation intensities, and filtered with radar quality index (RQI) thresholds and precipitation types. Preliminary comparisons of Day-1 GPM products and Q3 are in reasonably good overall agreement. Based on the mission-to-date (expected to be March 2014 - November 2015) data from all GPM overpasses, the biases relative to Q3 for GMI and DPR precipitation estimates at 0.5o resolution are negative, whereas the biases for CMB precipitation estimates are positive. Based on all available data (March-July 2015 at this writing), the CONUS-averaged near-real-time IMERG Late Run hourly precipitation estimate is about 33% higher than MRMS. Detailed comparison results are available at http://wallops-prf.gsfc.nasa.gov/NMQ/. This evaluation is carried out over the CONUS. Additional work is required to determine how applicable the results drawn from this land area might be to oceanic areas and regional land sites, as the precipitation error statistics can be highly regime dependent. Accordingly, the authors plan to conduct more comprehensive comparisons over a variety of regimes as GPM continues its mission.

  10. Extreme precipitation patterns and reductions of terrestrial ecosystem production across biomes

    NASA Astrophysics Data System (ADS)

    Zhang, Yongguang; Susan Moran, M.; Nearing, Mark A.; Ponce Campos, Guillermo E.; Huete, Alfredo R.; Buda, Anthony R.; Bosch, David D.; Gunter, Stacey A.; Kitchen, Stanley G.; Henry McNab, W.; Morgan, Jack A.; McClaran, Mitchel P.; Montoya, Diane S.; Peters, Debra P. C.; Starks, Patrick J.

    2013-03-01

    Precipitation regimes are predicted to shift to more extreme patterns that are characterized by more heavy rainfall events and longer dry intervals, yet their ecological impacts on vegetation production remain uncertain across biomes in natural climatic conditions. This in situ study investigated the effects of these climatic conditions on aboveground net primary production (ANPP) by combining a greenness index from satellite measurements and climatic records during 2000-2009 from 11 long-term experimental sites in multiple biomes and climates. Results showed that extreme precipitation patterns decreased the sensitivity of ANPP to total annual precipitation (PT) at the regional and decadal scales, leading to decreased rain use efficiency (RUE; by 20% on average) across biomes. Relative decreases in ANPP were greatest for arid grassland (16%) and Mediterranean forest (20%) and less for mesic grassland and temperate forest (3%). The cooccurrence of heavy rainfall events and longer dry intervals caused greater water stress conditions that resulted in reduced vegetation production. A new generalized model was developed using a function of both PT and an index of precipitation extremes and improved predictions of the sensitivity of ANPP to changes in precipitation patterns. Our results suggest that extreme precipitation patterns have substantially negative effects on vegetation production across biomes and are as important as PT. With predictions of more extreme weather events, forecasts of ecosystem production should consider these nonlinear responses to altered extreme precipitation patterns associated with climate change.

  11. Germanium recovery from gasification fly ash: evaluation of end-products obtained by precipitation methods.

    PubMed

    Arroyo, Fátima; Font, Oriol; Fernández-Pereira, Constantino; Querol, Xavier; Juan, Roberto; Ruiz, Carmen; Coca, Pilar

    2009-08-15

    In this study the purity of the germanium end-products obtained by two different precipitation methods carried out on germanium-bearing solutions was evaluated as a last step of a hydrometallurgy process for the recovery of this valuable element from the Puertollano Integrated Gasification Combined Cycle (IGCC) fly ash. Since H(2)S is produced as a by-product in the gas cleaning system of the Puertollano IGCC plant, precipitation of germanium as GeS(2) was tested by sulfiding the Ge-bearing solutions. The technological and hazardous issues that surround H(2)S handling conducted to investigate a novel precipitation procedure: precipitation as an organic complex by adding 1,2-dihydroxy benzene pyrocatechol (CAT) and cetyltrimethylammonium bromide (CTAB) to the Ge-bearing solutions. Relatively high purity Ge end-products (90 and 93% hexagonal-GeO(2) purity, respectively) were obtained by precipitating Ge from enriched solutions, as GeS(2) sulfiding the solutions with H(2)S, or as organic complex with CAT/CTAB mixtures and subsequent roasting of the precipitates. Both methods showed high efficiency (>99%) to precipitate selectively Ge using a single precipitation stage from germanium-bearing solutions.

  12. ARSENATE CARRIER PRECIPITATION METHOD OF SEPARATING PLUTONIUM FROM NEUTRON IRRADIATED URANIUM AND RADIOACTIVE FISSION PRODUCTS

    DOEpatents

    Thompson, S.G.; Miller, D.R.; James, R.A.

    1961-06-20

    A process is described for precipitating Pu from an aqueous solution as the arsenate, either per se or on a bismuth arsenate carrier, whereby a separation from uranium and fission products, if present in solution, is accomplished.

  13. Improving Spatiotemporal Representations of Extremes in High-Resolution Gridded Daily Precipitation Products

    NASA Astrophysics Data System (ADS)

    Oyler, J.; Nicholas, R.; Kinney, J. R.

    2016-12-01

    High-resolution gridded daily precipitation products are essential for both the evaluation and downscaling of climate models, and as inputs to assessments of climate impacts on local hydrology, ecosystem processes, and biotic communities. Here, we examine the ability of these products to capture regional precipitation trends and spatiotemporal variability in extremes within the conterminous U.S. Although the currently available products display similar spatial patterns for mean precipitation, they differ substantially in their representation of extremes. In several products, grid cells near station locations exhibit notable unrealistic differences in precipitation statistics compared to grid cells farther from station locations. To address these limitations, we present a new gridding framework that not only captures locally relevant topoclimate spatial patterns, but also provides temporally consistent gridded daily precipitation estimates that more accurately capture spatiotemporal variability in extremes and regional climate trends. The framework includes station observation homogenization, time-of-observation adjustments and missing value infilling to ensure better temporal consistency, and a two-step spatiotemporal regression kriging approach for interpolating both precipitation occurrence and amount. We apply the dataset in the region surrounding the Chesapeake Bay Watershed in the eastern U.S. to create a 1948 to present daily, 4-km resolution gridded precipitation dataset. The gridding framework and resulting dataset provide an invaluable tool for climate model downscaling and for local climate impacts, adaptation, and vulnerability assessments.

  14. Assessing the performance of satellite-based precipitation products over the Mediterranean region

    NASA Astrophysics Data System (ADS)

    Xaver, Angelika; Dorigo, Wouter; Brocca, Luca; Ciabatta, Luca

    2017-04-01

    Detailed knowledge about the spatial and temporal patterns and quantities of precipitation is of high importance. This applies especially in the Mediterranean region, where water demand for agricultural, industrial and touristic needs is growing and climate projections foresee a decrease of precipitation amounts and an increase in variability. In this region, ground-based rain gauges are available only limited in number, particularly in northern Africa and the Middle East and lack to capture the high spatio-temporal character of precipitation over large areas. This has motivated the development of a large number of remote sensing products for monitoring rainfall. Satellite-based precipitation products are based on various observation principles and retrieval approaches, i.e. from thermal infra-red and microwaves. Although, many individual validation studies on the performance of these precipitation datasets exist, they mostly examine only one or a few of these rainfall products at the same time and are not targeted at the Mediterranean basin as a whole. Here, we present an extensive comparative study of seven different satellite-based precipitation products, namely CMORPH 30-minutes, CMORPH 3-hourly, GPCP, PERSIANN, SM2Rain CCI, TRMM TMPA 3B42, and TRMM TMPA 3B42RT, focusing on the whole Mediterranean region and on individual Mediterranean catchments. The time frame of investigation is restricted by the common availability of all precipitation products and covers the period 2000-2013. We assess the skill of the satellite products against gridded gauge-based data provided by GPCC and E-OBS. Apart from common characteristics like biases and temporal correlations we evaluate several sophisticated dataset properties that are of particular interest for Mediterranean hydrology, including the capability of the remotely sensed products to capture extreme events and trends. A clear seasonal dependency of the correlation results can be observed for the whole Mediterranean

  15. PROCESS USING BISMUTH PHOSPHATE AS A CARRIER PRECIPITATE FOR FISSION PRODUCTS AND PLUTONIUM VALUES

    DOEpatents

    Finzel, T.G.

    1959-03-10

    A process is described for separating plutonium from fission products carried therewith when plutonium in the reduced oxidation state is removed from a nitric acid solution of irradiated uranium by means of bismuth phosphate as a carrier precipitate. The bismuth phosphate carrier precipitate is dissolved by treatment with nitric acid and the plutonium therein is oxidized to the hexavalent oxidation state by means of potassium dichromate. Separation of the plutonium from the fission products is accomplished by again precipitating bismuth phosphate and removing the precipitate which now carries the fission products and a small percentage of the plutonium present. The amount of plutonium carried in this last step may be minimized by addition of sodium fluoride, so as to make the solution 0.03N in NaF, prior to the oxidation and prccipitation step.

  16. Precipitation Seasonality over the Indian Subcontinent: Assessment of Gauge, Reanalyses and Satellite Products

    NASA Astrophysics Data System (ADS)

    Renwick, J. A.; Rana, S.; McGregor, J.

    2015-12-01

    This work addresses the seasonal (winter, pre-monsoon, monsoon and post-monsoon) performance of seven precipitation products from three different data sources: gridded station data, satellite-derived data and reanalyses products over the Indian Subcontinent, for a period of 10 years (1997/98 to 2006/07). Precipitation products evaluated are the Asian Precipitation - Highly Resolved Observational Data Integration Towards Evaluation of Water Resources (APHRODITE), the Climate Prediction Center unified gauge (CPC-uni), the Global Precipitation Climatology project (GPCP), Tropical Rainfall Measuring Mission (TRMM) post real-time research products (3B42-V6 and 3B42-V7), the Climate Forecast System Reanalysis (CFSR) and the European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Re-Analysis (ERA-Interim). Several verification measures are employed to assess the accuracy of the data. All datasets capture the large-scale characteristics of the seasonal mean precipitation distribution, albeit with pronounced seasonal and/or regional differences. Compared to APHRODITE, the gauge-only (CPC-uni) and the satellite-derived precipitation products (GPCP, 3B42-V6 and 3B42-V7) capture the summer monsoon rainfall variability better than CFSR and ERA-Interim. Similar conclusions were drawn for the post-monsoon season, with the exception of 3B42-V7, which underestimates post-monsoon precipitation. Over mountainous regions 3B42-V7 shows an appreciable improvement over 3B42-V6 and other gauge-based precipitation products. Significantly large biases/errors occur during the winter months, which is likely related to the uncertainty in observations that artificially inflate the existing error in reanalyses and satellite retrievals.

  17. Next-Generation Satellite Precipitation Products for Understanding Global and Regional Water Variability

    NASA Technical Reports Server (NTRS)

    Hou, Arthur Y.

    2011-01-01

    A major challenge in understanding the space-time variability of continental water fluxes is the lack of accurate precipitation estimates over complex terrains. While satellite precipitation observations can be used to complement ground-based data to obtain improved estimates, space-based and ground-based estimates come with their own sets of uncertainties, which must be understood and characterized. Quantitative estimation of uncertainties in these products also provides a necessary foundation for merging satellite and ground-based precipitation measurements within a rigorous statistical framework. Global Precipitation Measurement (GPM) is an international satellite mission that will provide next-generation global precipitation data products for research and applications. It consists of a constellation of microwave sensors provided by NASA, JAXA, CNES, ISRO, EUMETSAT, DOD, NOAA, NPP, and JPSS. At the heart of the mission is the GPM Core Observatory provided by NASA and JAXA to be launched in 2013. The GPM Core, which will carry the first space-borne dual-frequency radar and a state-of-the-art multi-frequency radiometer, is designed to set new reference standards for precipitation measurements from space, which can then be used to unify and refine precipitation retrievals from all constellation sensors. The next-generation constellation-based satellite precipitation estimates will be characterized by intercalibrated radiometric measurements and physical-based retrievals using a common observation-derived hydrometeor database. For pre-launch algorithm development and post-launch product evaluation, NASA supports an extensive ground validation (GV) program in cooperation with domestic and international partners to improve (1) physics of remote-sensing algorithms through a series of focused field campaigns, (2) characterization of uncertainties in satellite and ground-based precipitation products over selected GV testbeds, and (3) modeling of atmospheric processes and

  18. Supporting Hydrometeorological Research and Applications with Global Precipitation Measurement (GPM) Products and Services

    NASA Technical Reports Server (NTRS)

    Liu, Zhong; Ostrenga, D.; Vollmer, B.; Deshong, B.; MacRitchie, K.; Greene, M.; Kempler, S.

    2016-01-01

    Precipitation is an important dataset in hydrometeorological research and applications such as flood modeling, drought monitoring, etc. On February 27, 2014, the NASA Global Precipitation Measurement (GPM) mission was launched to provide the next-generation global observations of rain and snow (http:pmm.nasa.govGPM). The GPM mission consists of an international network of satellites in which a GPM Core Observatory satellite carries both active and passive microwave instruments to measure precipitation and serve as a reference standard, to unify precipitation measurements from a constellation of other research and operational satellites. The NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC) hosts and distributes GPM data. The GES DISC is home to the data archive for the GPM predecessor, the Tropical Rainfall Measuring Mission (TRMM). GPM products currently available include the following:1. Level-1 GPM Microwave Imager (GMI) and partner radiometer products2. Goddard Profiling Algorithm (GPROF) GMI and partner products (Level-2 and Level-3)3. GPM dual-frequency precipitation radar and their combined products (Level-2 and Level-3)4. Integrated Multi-satellitE Retrievals for GPM (IMERG) products (early, late, and final run)GPM data can be accessed through a number of data services (e.g., Simple Subset Wizard, OPeNDAP, WMS, WCS, ftp, etc.). A newly released Unified User Interface or UUI is a single interface to provide users seamless access to data, information and services. For example, a search for precipitation products will not only return TRMM and GPM products, but also other global precipitation products such as MERRA (Modern Era Retrospective-Analysis for Research and Applications), GLDAS (Global Land Data Assimilation Systems), etc.New features and capabilities have been recently added in GIOVANNI to allow exploring and inter-comparing GPM IMERG (Integrated Multi-satelliE Retrievals for GPM) half-hourly and monthly precipitation

  19. Evolving Capabilities and Expectations for the GPCP Precipitation Products

    NASA Astrophysics Data System (ADS)

    Huffman, G. J.; Adler, R. F.; Bolvin, D. T.; Nelkin, E. J.

    2014-12-01

    The Global Precipitation Climatology Project (GPCP) was established in the mid-1990's to determine whether the then-new passive microwave sensors could reliably depict quasi-global variations in precipitation, in particular those associated with El Niño Southern Oscillation (ENSO) events. This international community-based effort was successful, and its data record now extends past 35 years. In the process, we have found ways to use estimates from sensors flying before the passive microwave era, and estimates for polar regions in which the passive microwave retrievals are not useful, as well as providing pentad (5-day) and daily estimates (the latter for a subset of the 1979-present record). Several versions have been released as lessons learned and new input datasets have been applied to the computation. Among these lessons are the importance of maintaining consistency in input data sources, requiring consistent processing for the entire record of input datasets, and ensuring completeness in data coverage. The resulting data sets were not originally designed to be formal Climate Data Records (CDRs), but they do emphasize homogeneity, high quality, and stability in the input data sets. The success of the datasets has raised user expectations and encouraged a variety of analyses that were not envisioned in the original design. In particular, the GPCP data contain approximations that make it difficult for the data to adequately represent fine-scale "extremes". As well, improved input data sets and algorithms have been developed which are not accommodated in the current version. In response, the GPCP is working under NASA MEaSUREs funding to create a next-generation version at finer scale that is better suited for a wider range of analyses. The widening circle of non-expert users has widened the range of formats and services that are needed. These developments increase the utility of such data sets to users, with the unintended effect that the cost of getting a data

  20. Validation of IMERG Satellite Precipitation Product over Ocean and Land against Gauge and Radar Data

    NASA Astrophysics Data System (ADS)

    Maggioni, V.; Khan, S.

    2016-12-01

    The recent Integrated Multi-satellitE Retrievals for Global Precipitation (IMERG) satellite product, which fuses information from multiple sources, offers significant promise over previous satellite products. An important step in its validation and evolution is the quantification of its uncertainties. The objective of this study is to investigate the performance of IMERG over oceans (Atlantic, Indian and Pacific) against the NOAA-Tropical Atmosphere Ocean (TAO) gauge measurements. The buoy precipitation data from the PIRATA, RAMA and TRITION stations are employed for comparison with the IMERG satellite precipitation product at different temporal resolutions. Statistical metrics like hit bias, correlation, root mean square error, probability of detection (POD) and success ratio (SR) are computed and illustrated using the performance and Taylor diagrams. The initial findings reveal high POD values (Atlantic: 0.79, Indian: 0.86 and Pacific: 0.82) over the three oceans but very low SR values. The respective correlation coefficients are Atlantic: 0.34, Indian: 0.2 and Pacific: 0.46 (p<0.001). This analysis complements our recent investigation of IMERG product over land against the Dual frequency Precipitation Radar (DPR) and Multi Radar Multi Sensor system (MRMS) precipitation data. The future study will verify the viability of using DPR as a reference for IMERG error estimation over oceans. This work therefore encompasses a thorough investigation of uncertainties associated with IMERG satellite product over both land and ocean, taking into account the geographical and climatic implications.

  1. Comparison of five gridded precipitation products at climatological scales over West Africa

    NASA Astrophysics Data System (ADS)

    Akinsanola, A. A.; Ogunjobi, K. O.; Ajayi, V. O.; Adefisan, E. A.; Omotosho, J. A.; Sanogo, S.

    2016-12-01

    The paper aimed at assessing the capabilities and limitations of five different precipitation products to describe rainfall over West Africa. Five gridded precipitation datasets of the Tropical Rainfall Measurement Mission (TRMM) Multi-Platform Analysis (TMPA 3B43v7); University of Delaware (UDEL version 3.01); Climatic Research Unit (CRU version 3.1); Global Precipitation Climatology Centre (GPCC version 7) and African Rainfall Climatology (ARC version 2) were compared and validated with reference ground observation data from 81 stations spanning a 19-year period, from January 1990 to December 2008. Spatial investigation of the precipitation datasets was performed, and their capability to replicate the inter-annual and intra-seasonal variability was also assessed. The ability of the products to capture the El Nino and La Nina events were also assessed. Results show that all the five datasets depicted similar spatial distribution of mean rainfall climatology, although differences exist in the total rainfall amount for each precipitation dataset. Further analysis shows that the three distinct phases of the mean annual cycle of the West Africa Monsoon precipitation were well captured by the datasets. However, CRU, GPCC and UDEL failed to capture the little dry season in the month of August while UDEL and GPCC underestimated rainfall amount in the Sahel region. Results of the inter-annual precipitation anomalies shows that ARC2 fail to capture about 46% of the observed variability while the other four datasets exhibits a greater performance (r > 0.9). All the precipitation dataset except ARC2 were consistent with the ground observation in capturing the dry and wet conditions associated with El Nino and La Nina events, respectively. ARC2 tends to overestimate the El Nino event and failed to capture the La Nina event in all the years considered. In general GPCC, CRU and TRMM were found to be the most outstanding datasets and can, therefore, be used for precipitation

  2. MODIS EVI as a proxy for net primary production across precipitation regimes

    USDA-ARS?s Scientific Manuscript database

    Above ground net primary production (ANPP) is a measure of the rate of photosynthesis in an ecosystem, and is indicative of its biomass productivity. Prior studies have reported a relationship between ANPP and annual precipitation which converged across biomes in dry years. This deserves further s...

  3. A modeling approach to soil type and precipitation seasonality interactions on bioenergy crop production

    USDA-ARS?s Scientific Manuscript database

    Precipitation limits primary production by affecting soil moisture, and soil type interacts with soil moisture to determine soil water availability to plants. We used ALMANAC, a process-based model, to simulate switchgrass (Panicum virgatum var. Alamo) biomass production in Central Texas under thre...

  4. Systematic investigation of the cavi-precipitation process for the production of ibuprofen nanocrystals.

    PubMed

    Sinha, Biswadip; Müller, Rainer H; Möschwitzer, Jan P

    2013-12-31

    Cavi-precipitation process is a combinative particle size reduction technology based on solvent-anti-solvent precipitation coupled high pressure homogenization (HPH). The cavi-precipitation can be used for the efficient production of drug nanocrystals (NC) with improved dissolution rate leading to better bioavailability. The work presented here demonstrates the advantage of cavi-precipitation process over the standard HPH processes and standard combination process (decoupled process) where precipitation is performed outside the homogenizer. The model compound ibuprofen (IBP) was solubilized in isopropanol (IPA) to constitute the solvent phase and mixed with the anti-solvent phase (0.1% (w/v) hydroxypropyl methylcellulose with 0.2% (w/v) sodium dodecyl sulphate) at different ratios to carry out the precipitation step. IBP-IPA-Water composition was selected from ternary diagram for a highly supersaturated zone to obtain smaller size particles. The mean particle size [d(0.5)] obtained by this process (300nm) was much smaller when compared to that obtained from the decoupled process (1.5μm). Optimization of the solvent-anti-solvent ratio and drug concentration was necessary to achieve a smaller particle size. PXRD and DSC results revealed that the solid state properties of the original IBP and the prepared NC samples by cavi-precipitation samples were similar.

  5. Analyses of Chinese Hourly Precipitation Using Gauge Observations and Satellite Estimates Products

    NASA Astrophysics Data System (ADS)

    Pan, Y.; Yu, J.; Shen, Y.

    2010-12-01

    Highly spatial-temporal and accurate precipitation analyses are essential for monitoring the catastrophic mesoscale weather systems, examining numerical model outputs, and doing dynamic researches on mesoscale meteorology. In recent years, Chinese government has gradually developed a ground-based observational net of 30000 auto-weather-stations (AWS) all over the country, most of which are in the eastern and southern China. The real-time data of gauged rainfall is transported to National Meteorological Information of China (NMIC) every hour, and its quality has been strictly and effectually controlled. Taking advantage of these resources, an hourly Chinese Precipitation Analyses Products (CPAP) with fine resolution is developed. But on the Tibetan Plateau where the AWS is still sparse, the accuracy of precipitation can not satisfy the operational needs yet. Otherwise, CMORPH has a well performance on the space structure of rainfall over China in warm season, but loses on intensity. Thus, we make a merge test analysis at resolution of 0.1 ×0.1 degree , using Optimum Interpolation (OI) to combine hourly CPAP with CMORPH estimates precipitation products. Before OI,the systematic bias in CMORPH have been partly corrected by gauge data through PDF adjustments. The validation of the merge test from June to August 2009 shows that, the combined products can obviously reduce the bias to the gauge analyses CPAP, and also have highly coefficient with it. It is more important that, the combined products provide a reasonable and full-covered precipitation structure over Tibetan Plateau.

  6. Productivity responses of desert vegetation to precipitation patterns across a rainfall gradient.

    PubMed

    Li, Fang; Zhao, Wenzhi; Liu, Hu

    2015-03-01

    The influences of previous-year precipitation and episodic rainfall events on dryland plants and communities are poorly quantified in the temperate desert region of Northwest China. To evaluate the thresholds and lags in the response of aboveground net primary productivity (ANPP) to variability in rainfall pulses and seasonal precipitation along the precipitation-productivity gradient in three desert ecosystems with different precipitation regimes, we collected precipitation data from 2000 to 2012 in Shandan (SD), Linze (LZ) and Jiuquan (JQ) in northwestern China. Further, we extracted the corresponding MODIS Normalized Difference Vegetation Index (NDVI, a proxy for ANPP) datasets at 250 m spatial resolution. We then evaluated different desert ecosystems responses using statistical analysis, and a threshold-delay model (TDM). TDM is an integrative framework for analysis of plant growth, precipitation thresholds, and plant functional type strategies that capture the nonlinear nature of plant responses to rainfall pulses. Our results showed that: (1) the growing season NDVIINT (INT stands for time-integrated) was largely correlated with the warm season (spring/summer) at our mildly-arid desert ecosystem (SD). The arid ecosystem (LZ) exhibited a different response, and the growing season NDVIINT depended highly on the previous year's fall/winter precipitation and ANPP. At the extremely arid site (JQ), the variability of growing season NDVIINT was equally correlated with the cool- and warm-season precipitation; (2) some parameters of threshold-delay differed among the three sites: while the response of NDVI to rainfall pulses began at about 5 mm for all the sites, the maximum thresholds in SD, LZ, and JQ were about 55, 35 and 30 mm respectively, increasing with an increase in mean annual precipitation. By and large, more previous year's fall/winter precipitation, and large rainfall events, significantly enhanced the growth of desert vegetation, and desert ecosystems

  7. Evaluation of Satellite and Ground Based Precipitation Products for Flood Forecasting

    NASA Astrophysics Data System (ADS)

    Chintalapudi, S.; Sharif, H.; Yeggina, S.

    2012-04-01

    The development in satellite-derived rainfall estimates encouraged the hydrological modeling in sparse gauged basins or ungauged basins. Especially, physically-based distributed hydrological models can benefit from the good spatial and temporal coverage of satellite precipitation products. In this study, three satellite derived precipitation datasets (TRMM, CMORPH, and PERSIANN), NEXRAD, and rain gauge precipitation datasets were used to drive the hydrological model. The physically-based, distributed hydrological model Gridded Surface Subsurface Hydrological Analysis (GSSHA) was used in this study. Focus will be on the results from the Guadalupe River Basin above Canyon Lake and below Comfort, Texas. The Guadalupe River Basin above Canyon Lake and below Comfort Texas drains an area of 1232 km2. Different storm events will be used in these simulations. August 2007 event was used as calibration and June 2007 event was used as validation. Results are discussed interms of accuracy of satellite precipitation estimates with the ground based precipitation estimates, predicting peak discharges, runoff volumes, time lag, and spatial distribution. The initial results showed that, model was able to predict the peak discharges and runoff volumes when using NEXRAD MPE data, and TRMM 3B42 precipitation product. The results also showed that there was time lag in hydrographs driven by both PERSIANN and CMORPH data sets.

  8. Precipitation legacies in desert grassland primary production occur through previous-year tiller density.

    PubMed

    Reichmann, Lara G; Sala, Osvaldo E; Peters, Debra P C

    2013-02-01

    In arid ecosystems, current-year precipitation often explains only a small proportion of annual aboveground net primary production (ANPP). We hypothesized that lags in the response of ecosystems to changes in water availability explain this low explanatory power, and that lags result from legacies from transitions from dry to wet years or the reverse. We explored five hypotheses regarding the magnitude of legacies, two possible mechanisms, and the differential effect of previous dry or wet years on the legacy magnitude. We used a three-year manipulative experiment with five levels of rainfall in the first two years (-80% and -50% reduced annual precipitation (PPT), ambient, +50% and +80% increased PPT), and reversed treatments in year 3. Legacies of previous two years, which were dry or wet, accounted for a large fraction (20%) of interannual variability in production on year 3. Legacies in ANPP were similar in absolute value for both types of precipitation transitions, and their magnitude was a function of the difference between previous and current-year precipitation. Tiller density accounted for 40% of legacy variability, while nitrogen and carryover water availability showed no effect. Understanding responses to changes in interannual precipitation will assist in assessing ecosystem responses to climate change-induced increases in precipitation variability.

  9. Legacies of precipitation fluctuations on primary production: theory and data synthesis

    PubMed Central

    Sala, Osvaldo E.; Gherardi, Laureano A.; Reichmann, Lara; Jobbágy, Esteban; Peters, Debra

    2012-01-01

    Variability of above-ground net primary production (ANPP) of arid to sub-humid ecosystems displays a closer association with precipitation when considered across space (based on multiyear averages for different locations) than through time (based on year-to-year change at single locations). Here, we propose a theory of controls of ANPP based on four hypotheses about legacies of wet and dry years that explains space versus time differences in ANPP–precipitation relationships. We tested the hypotheses using 16 long-term series of ANPP. We found that legacies revealed by the association of current- versus previous-year conditions through the temporal series occur across all ecosystem types from deserts to mesic grasslands. Therefore, previous-year precipitation and ANPP control a significant fraction of current-year production. We developed unified models for the controls of ANPP through space and time. The relative importance of current-versus previous-year precipitation changes along a gradient of mean annual precipitation with the importance of current-year PPT decreasing, whereas the importance of previous-year PPT remains constant as mean annual precipitation increases. Finally, our results suggest that ANPP will respond to climate-change-driven alterations in water availability and, more importantly, that the magnitude of the response will increase with time. PMID:23045711

  10. Comparison of Rainfall Products Derived from TRMM Microwave Imager and Precipitation Radar.

    NASA Astrophysics Data System (ADS)

    Masunaga, Hirohiko; Iguchi, Toshio; Oki, Riko; Kachi, Misako

    2002-08-01

    Satellite remote sensing is an indispensable means of measuring and monitoring precipitation on a global scale. The Tropical Rainfall Measuring Mission (TRMM) is continuing to make significant progress in helping the global features of precipitation to be understood, particularly with the help of a pair of spaceborne microwave sensors, the TRMM Microwave Imager (TMI) and precipitation radar (PR). The TRMM version-5 standard products, however, are known to have a systematic inconsistency in mean monthly rainfall. To clarify the origin of this inconsistency, the authors investigate the zonal mean precipitation and the regional trends in the hydrometeor profiles in terms of the precipitation water content (PWC) and the precipitation water path (PWP) derived from the TMI profiling algorithm (2A12) and the PR profile (2A25). An excess of PR over TMI in near-surface PWC is identified in the midlatitudes (especially in winter), whereas PWP exhibits a striking excess of TMI over PR around the tropical rainfall maximum. It is shown that these inconsistencies arise from TMI underestimating the near-surface PWC in midlatitude winter and PR underestimating PWP in the Tropics. This conclusion is supported by the contoured-frequency-by-altitude diagrams as a function of PWC. Correlations between rain rate and PWC/PWP indicate that the TMI profiling algorithm tends to provide a larger rain rate than the PR profile under a given PWC or PWP, which exaggerates the excess by TMI and cancels the excess by PR through the conversion from precipitation water to rain rate. As a consequence, the disagreement in the rainfall products between TMI and PR is a combined result of the intrinsic bias originating from the different physical principles between TMI and PR measurements and the purely algorithmic bias inherent in the conversion from precipitation water to rain rate.

  11. Depiction of global drought by reanalysis and real-time satellite precipitation products

    NASA Astrophysics Data System (ADS)

    Wood, Eric; Zhan, Wang

    2017-04-01

    Reanalysis precipitation is routinely used as a surrogate of observations due to its high spatial and temporal resolution and global coverage, and thus widely used in hydrologic and agricultural applications. The resultant product is largely dependent on the accuracy of reanalysis precipitation datasets. With advances in satellite remote sensing technology, the latest generation of reanalysis systems starts to include real time satellite precipitation estimates as inputs to their assimilation system. In this presentation, reanalysis precipitations datasets and real-time satellite rainfall products are used for the depiction of global drought events by comparing them against an observational reference dataset, namely the Princeton Global Forcing (PGF) dataset, during the period of March 2000 to December 2012. The selected reanalyses are the Climate Forecast System Reanalysis (CFSR), ERA-Interim, and the Modern-Era Retrospective Analysis for Research and Applications, version 1 (MERRA) and 2 (MERRA-2). Three real-time satellite precipitation estimates; namely the Tropical Rainfall Measuring Mission (TRMM) Multi-Satellite Precipitation Analysis (TMPA) 3B42RT, the Climate Prediction Center (CPC) morphing algorithm (CMORPH) and the Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN) are included in the study. Our results show that all datasets depict Sub-Saharan African drought events with limited skill, as opposed to mid latitude regions. Reanalyses and satellite real-time precipitation datasets have comparative skill in the low latitudes. Specific drought events are analyzed that demonstrate the drought depiction from the various datasets. In North America, Asia and Europe, drought events are better replicated and inter-dataset variability is significantly smaller. Overall, temporal characteristics of identified drought events are better estimated than their spatial extent.

  12. New Products for Near Real-Time Enhanced Landslide Identification and Precipitation Monitoring

    NASA Astrophysics Data System (ADS)

    Roberts-Pierel, J.; Ahamed, A.; Fayne, J.; Rumsey, A.

    2015-12-01

    Nepal and the Himalayan region are hotspots for landslide activity due to mountainous topography, complex terrain, and monsoon rains. Current research in landslide modeling and detection generally requires high resolution imagery with software aided classification or manual digitization by analysts. These methods are plagued by low spatial and temporal accuracy. Addressing issues in conventional measurement, this study combined optical data from Landsat 8, a Digital Elevation Model (DEM) generated from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), and precipitation data from the Global Precipitation Measurement Mission (GPM) to create two products. The Sudden Landslide Identification Product (SLIP) uses Landsat 8 and the ASTER DEM to identify landslides in near real-time, and provides damage assessments by mapping landslides triggered by precipitation. Detecting Real-time Increased Precipitation (DRIP) monitors precipitation levels extracted from the GPM-IMERG 30-minute product to create alerts in near real-time when current rainfall levels exceed regional threshold values. After a landslide detection is made by SLIP, historical rainfall data from DRIP is analyzed to estimate a date for the detected landslide. Together, DRIP and SLIP will be used by local and regional organizations in Nepal such as the International Centre for Integrated Mountain Development (ICIMOD), as well as the international scientific community to protect lives, preserve infrastructure, and manage local ecosystems.

  13. A Method to Optimally Merge Precipitation Products for Land Surface Modeling

    NASA Astrophysics Data System (ADS)

    Hazra, A.; Maggioni, V.; Houser, P.

    2016-12-01

    Precipitation is the most influential meteorological forcing variable for land surface modeling, providing moisture for processes such as runoff, biogeochemical cycling, evaporation, transpiration, groundwater recharge, and soil moisture. However, precipitation estimates from rain gauge, ground-based radar, satellite, and numerical models have significant uncertainties, which can be amplified when exposed to highly non-linear land model physics. Our study is based on the hypothesis that a combination of precipitation data from different sources optimized to minimize the hydrologic response will improve coupled model forecast skill. And our objective is to develop an optimal precipitation dataset that combines the advantages of high-resolution products for improving land surface modeling skill (i.e., soil moisture estimation). For this study three precipitation products (satellite product, ground-based radar, and model estimates) are merged and trained to minimize the difference between soil moisture model estimates and newly emerging satellite soil moisture observations. An uncoupled demonstration over the CONUS with specific validation activities over the Southern Great Plains will be shown.

  14. Reconstruction of precipitation fields out of rain-gauge data in comparison to radar based products

    NASA Astrophysics Data System (ADS)

    Maurer, R.; Schüttemeyer, D.; Gerlach, N.; Simmer, C.

    2009-04-01

    During the last decades large progress was made in the area of precipitation observation mostly related to new methods for remote sensing of precipitation. Radar observations together with passive microwave precipitation measurements have proven to be reliable in this context. However, there is still a need for more extensively exploiting the spatial and temporal variability of the obtained signals, motivated - for instance - by the demand of reliable flood warning systems. To estimate precipitation with the required accuracy the current study examines a technique to construct precipitation fields out of data of a number of spatial distributed rain-gauges by a combination of kriging and fuzzy-logic. This method was applied for a period of 3 years (2005-2008, with 133 rain gauges for about 40.000km²) for one state (Rhineland-Palatinate) in Germany. The method was compared to the operational RADOLAN product of the German Weather Service (DWD). This hourly data set is based on a radar composite created from 16 German radar sites and adjusted to online available high-resolution rain gauge observations. Both procedures were tested independently from each other by cross-correlation. It is shown that the rain-gauge based method on average closely measures up to the accuracy of the RADOLAN product, but in convective situations RADOLAN clearly shows an enhanced performance. For stratiform precipitation fields RADOLAN possesses larger deviations compared to the rain-gauge based product. Due to restrictions in the number of rain gauges an integration of radar-data is indispensable. Thus, it is concluded that the described technique together with thoroughly quality controlled Radar measurements can give reliable estimates of quantitative precipitation suitable for numerous applications in hydrology and meteorology.

  15. Hourly to 5-minute temporal disaggregation of a merged radar-raingauge precipitation product

    NASA Astrophysics Data System (ADS)

    Barton, Yannick; Martius, Olivia; Germann, Urs; Sideris, Ioannis

    2017-04-01

    Temporally (and spatially) highly resolved precipitation data is of central importance for the assessment of historical local high impact precipitation events and for nowcasting applications. In Switzerland, quantitative precipitation estimations with a high temporal resolution are provided by radar reflectivity or raingauge measurements with a resolution of 5 and 10 minutes, respectively. The combination of both data sources on a 10-minute resolution is challenging for many reasons, among them are a shift in time between remote and ground observations, horizontal drifts caused by wind and variability in precipitation within a radar pixel. Hence the geostatistical merging of both radar derived precipitation and raingauge measurements is done using hourly aggregated precipitation. A new method to disaggregate the hourly rainfall product called CombiPrecip into 5-minute rainfall maps for Switzerland is presented here. CombiPrecip is a real-time precipitation data set developed by MeteoSwiss. By means of kriging, it uses hourly radar and raingauge information to produce "raingauge corrected" hourly precipitation of the same spatial resolution as the radar (1 km2). Here, a method is proposed to temporally disaggregate the hourly precipitation into final 5-minute accumulations (CPC5). The 5-minute radar accumulations (AQC5) are known. In theory, for a given hour, CPC5 can be estimated by multiplying each of the 12 AQC5 with the ratio of the hourly CombiPrecip output (CPC60) and the hourly radar accumulations (AQC60). However, there are pixels where CPC60 is positive and AQC60 zero, e.g. when the raingauge sees precipitation where the radar does not, returning a missing value and creating sharp precipitation gradients in the CPC5 images. Here, a solution to the missing values is presented. First, 12 new AQC5 images are produced, in which the precipitation field is extended by means of a moving average box of size 3. Second, the new AQC5 images are aggregated to produce a

  16. A linear merging methodology for high-resolution precipitation products using spatiotemporal regression

    SciTech Connect

    Turlapaty, Anish C.; Younan, Nicolas H.; Anantharaj, Valentine G

    2012-01-01

    Currently, the only viable option for a global precipitation product is the merger of several precipitation products from different modalities. In this article, we develop a linear merging methodology based on spatiotemporal regression. Four highresolution precipitation products (HRPPs), obtained through methods including the Climate Prediction Center's Morphing (CMORPH), Geostationary Operational Environmental Satellite-Based Auto-Estimator (GOES-AE), GOES-Based Hydro-Estimator (GOES-HE) and Self-Calibrating Multivariate Precipitation Retrieval (SCAMPR) algorithms, are used in this study. The merged data are evaluated against the Arkansas Red Basin River Forecast Center's (ABRFC's) ground-based rainfall product. The evaluation is performed using the Heidke skill score (HSS) for four seasons, from summer 2007 to spring 2008, and for two different rainfall detection thresholds. It is shown that the merged data outperform all the other products in seven out of eight cases. A key innovation of this machine learning method is that only 6% of the validation data are used for the initial training. The sensitivity of the algorithm to location, distribution of training data, selection of input data sets and seasons is also analysed and presented.

  17. Identifying and Analyzing Uncertainty Structures in the TRMM Microwave Imager Precipitation Product over Tropical Ocean Basins

    NASA Technical Reports Server (NTRS)

    Liu, Jianbo; Kummerow, Christian D.; Elsaesser, Gregory S.

    2016-01-01

    Despite continuous improvements in microwave sensors and retrieval algorithms, our understanding of precipitation uncertainty is quite limited, due primarily to inconsistent findings in studies that compare satellite estimates to in situ observations over different parts of the world. This study seeks to characterize the temporal and spatial properties of uncertainty in the Tropical Rainfall Measuring Mission Microwave Imager surface rainfall product over tropical ocean basins. Two uncertainty analysis frameworks are introduced to qualitatively evaluate the properties of uncertainty under a hierarchy of spatiotemporal data resolutions. The first framework (i.e. 'climate method') demonstrates that, apart from random errors and regionally dependent biases, a large component of the overall precipitation uncertainty is manifested in cyclical patterns that are closely related to large-scale atmospheric modes of variability. By estimating the magnitudes of major uncertainty sources independently, the climate method is able to explain 45-88% of the monthly uncertainty variability. The percentage is largely resolution dependent (with the lowest percentage explained associated with a 1 deg x 1 deg spatial/1 month temporal resolution, and highest associated with a 3 deg x 3 deg spatial/3 month temporal resolution). The second framework (i.e. 'weather method') explains regional mean precipitation uncertainty as a summation of uncertainties associated with individual precipitation systems. By further assuming that self-similar recurring precipitation systems yield qualitatively comparable precipitation uncertainties, the weather method can consistently resolve about 50 % of the daily uncertainty variability, with only limited dependence on the regions of interest.

  18. Global Precipitation Products at NASA GES DISC for Supporting Agriculture Research and Applications

    NASA Technical Reports Server (NTRS)

    Liu, Zhong; Teng, W.; Ostrenga, D.; Albayrak, R.; Savtchenko, A.; Yang, W.; Vollmer, B.; Meyer, D.

    2017-01-01

    This presentation describes precipitation products available at the NASA GES DISC that support agricultural research. XXXX Key environmental variables for agriculture: precipitation, temperature, water (soil moisture), solar radiation, NDVI, etc. Rainfed agriculture - major farming practices that rely on rainfall for water. Rainfed agriculture: >95% of farmed land (sub- Saharan Africa); 90% (Latin America); 75% (Near East and North Africa); 65% (East Asia); 60% (South Asia). Precipitation is very important for rainfed agriculture. Droughts can cause severe damage. Precipitation information can be used to monitor the growing season. The Goddard Earth Sciences (GES) Data and Information Services Center (DISC), one of 12 NASA data centers, located in Greenbelt, Maryland, USA. The GES DISC is a major data archive center for global precipitation, water & energy cycles, atmospheric composition, and climate variability Global and regional precipitation datasets (satellite-based and data assimilation Data services (subsetting, format conversion, online visualization, etc.) User services are available FAQs, How to (recipes), Glossary, etc. Social media (Twitter, YouTube, User forum) Help desk (phone, email, online feedback) Training materials (ARSET => Applied Remote Sensing Training) Liu,

  19. Identifying and Analyzing Uncertainty Structures in the TRMM Microwave Imager Precipitation Product over Tropical Ocean Basins

    NASA Technical Reports Server (NTRS)

    Liu, Jianbo; Kummerow, Christian D.; Elsaesser, Gregory S.

    2016-01-01

    Despite continuous improvements in microwave sensors and retrieval algorithms, our understanding of precipitation uncertainty is quite limited, due primarily to inconsistent findings in studies that compare satellite estimates to in situ observations over different parts of the world. This study seeks to characterize the temporal and spatial properties of uncertainty in the Tropical Rainfall Measuring Mission Microwave Imager surface rainfall product over tropical ocean basins. Two uncertainty analysis frameworks are introduced to qualitatively evaluate the properties of uncertainty under a hierarchy of spatiotemporal data resolutions. The first framework (i.e. 'climate method') demonstrates that, apart from random errors and regionally dependent biases, a large component of the overall precipitation uncertainty is manifested in cyclical patterns that are closely related to large-scale atmospheric modes of variability. By estimating the magnitudes of major uncertainty sources independently, the climate method is able to explain 45-88% of the monthly uncertainty variability. The percentage is largely resolution dependent (with the lowest percentage explained associated with a 1 deg x 1 deg spatial/1 month temporal resolution, and highest associated with a 3 deg x 3 deg spatial/3 month temporal resolution). The second framework (i.e. 'weather method') explains regional mean precipitation uncertainty as a summation of uncertainties associated with individual precipitation systems. By further assuming that self-similar recurring precipitation systems yield qualitatively comparable precipitation uncertainties, the weather method can consistently resolve about 50 % of the daily uncertainty variability, with only limited dependence on the regions of interest.

  20. Validation and Development of the GPCP Experimental One-Degree Daily (1DD) Global Precipitation Product

    NASA Technical Reports Server (NTRS)

    Huffman, George J.; Adler, Robert F.; Bolvin, David T.; Einaud, Franco (Technical Monitor)

    2000-01-01

    The One-Degree Daily (1DD) precipitation dataset has been developed for the Global Precipitation Climatology Project (GPCP) and is currently in beta test preparatory to release as an official GPCP product. The 1DD provides a globally-complete, observation-only estimate of precipitation on a daily 1 deg. x 1 deg. grid for the period 1997 through early 2000 (by the time of the conference). In the latitude band 40N-40S the 1DD uses the Threshold-Matched Precipitation Index (TMPI), a GPI-like IR product with the pixel-level T(sub b) threshold and (single) conditional rain rate determined locally for each month by the frequency of precipitation in the GPROF SSM/I product and by, the precipitation amount in the GPCP monthly satellite-gauge (SG) combination. Outside 40N-40S the 1DD uses a scaled TOVS precipitation estimate that has month-by-month adjustments based on the TMPI and the SG. Early validation results are encouraging. The 1DD shows relatively large scatter about the daily validation values in individual grid boxes, as expected for a technique that depends on cloud-sensing schemes such as the TMPI and TOVS. On the other hand, the time series of 1DD shows good correlation with validation in individual boxes. For example, the 1997-1998 time series of 1DD and Oklahoma Mesonet values in a grid box in northeastern Oklahoma have the correlation coefficient = 0.73. Looking more carefully at these two time series, the number of raining days for the 1DD is within 7% of the Mesonet value, while the distribution of daily rain values is very similar. Other tests indicate that area- or time-averaging improve the error characteristics, making the data set highly attractive to users interested in stream flow, short-term regional climatology, and model comparisons. The second generation of the 1DD product is currently under development; it is designed to directly incorporate TRMM and other high-quality precipitation estimates. These data are generally sparse because they are

  1. Validation and Development of the GPCP Experimental One-Degree Daily (1DD) Global Precipitation Product

    NASA Technical Reports Server (NTRS)

    Huffman, George J.; Adler, Robert F.; Bolvin, David T.; Einaud, Franco (Technical Monitor)

    2000-01-01

    The One-Degree Daily (1DD) precipitation dataset has been developed for the Global Precipitation Climatology Project (GPCP) and is currently in beta test preparatory to release as an official GPCP product. The 1DD provides a globally-complete, observation-only estimate of precipitation on a daily 1 deg. x 1 deg. grid for the period 1997 through early 2000 (by the time of the conference). In the latitude band 40N-40S the 1DD uses the Threshold-Matched Precipitation Index (TMPI), a GPI-like IR product with the pixel-level T(sub b) threshold and (single) conditional rain rate determined locally for each month by the frequency of precipitation in the GPROF SSM/I product and by, the precipitation amount in the GPCP monthly satellite-gauge (SG) combination. Outside 40N-40S the 1DD uses a scaled TOVS precipitation estimate that has month-by-month adjustments based on the TMPI and the SG. Early validation results are encouraging. The 1DD shows relatively large scatter about the daily validation values in individual grid boxes, as expected for a technique that depends on cloud-sensing schemes such as the TMPI and TOVS. On the other hand, the time series of 1DD shows good correlation with validation in individual boxes. For example, the 1997-1998 time series of 1DD and Oklahoma Mesonet values in a grid box in northeastern Oklahoma have the correlation coefficient = 0.73. Looking more carefully at these two time series, the number of raining days for the 1DD is within 7% of the Mesonet value, while the distribution of daily rain values is very similar. Other tests indicate that area- or time-averaging improve the error characteristics, making the data set highly attractive to users interested in stream flow, short-term regional climatology, and model comparisons. The second generation of the 1DD product is currently under development; it is designed to directly incorporate TRMM and other high-quality precipitation estimates. These data are generally sparse because they are

  2. Developing GIOVANNI-based Online Prototypes to Intercompare TRMM-Related Global Gridded-Precipitation Products

    NASA Technical Reports Server (NTRS)

    Liu, Zhong; Ostrenga, Dana; Teng, William; Kempler, Steven; Milich, Lenard

    2014-01-01

    New online prototypes have been developed to extend and enhance the previous effort by facilitating investigation of product characteristics and intercomparison of precipitation products in different algorithms as well as in different versions at different spatial scales ranging from local to global without downloading data and software. Several popular Tropical Rainfall Measuring Mission (TRMM) products and the TRMM Composite Climatology are included. In addition, users can download customized data in several popular formats for further analysis. Examples show product quality problems and differences in several monthly precipitation products. It is seen that differences in daily and monthly precipitation products are distributed unevenly in space and it is necessary to have tools such as those presented here for customized and detailed investigations. A simple time series and two area maps allow the discovery of abnormal values of 3A25 in one of the months. An example shows a V-shaped valley issue in the Version 6 3B43 time series and another example shows a sudden drop in 3A25 monthly rain rate, all of which provide important information when the products are used for long-term trend studies. Future plans include adding more products and statistical functionality in the prototypes.

  3. Statistical Assessment of Precipitation Products: Case studies over Africa, Australia, and the Himalayas

    NASA Astrophysics Data System (ADS)

    Forootan, Ehsan; Khandu, Khandu; Awange, Joseph; Fereria, Vagner; Anyah, Richard

    2015-04-01

    Accurate and reliable spatial and temporal representation of precipitation variability is essential for water resource management as well as for understanding of various global (and regional) hydrological responses. The growing number of high-resolution precipitation products in the past decade requires a more rigorous evaluation process to understand their skills and limitations over different parts of the world. Using advanced statistical techniques of (complex) empirical orthogonal functions (EOF) and three-cornered-hat (TCH) methods, various monthly precipitation products derived from satellite-based measurements and global reanalyses over different climatic and topographic regimes such as Africa (2003-2010), Australia (1981-2014), the Himalayan region of Bhutan (1998-2012) were evaluated. The products were also assessed for their possible biases in terms of probability distribution and also in the spectral domain. The results indicated that while the precipitation products generally agreed reasonably well with gauge-based rainfall observations, their accuracies were widely different over the three regions. All the satellite-based products (CMORPH, CHIRP, TRMM) underestimated monsoon rain over the Himalayas, while some of them (CMORPH, GSMaP_MVK) systematically overestimated convective rainfall over central regions of the African rain-belt. Satellite-based CHIRP and the MERRA reanalysis product provided consistent long-term rainfall variability and change over Australia for the period 1981-2014 while the gauge-adjusted TRMM product (3B43 v7) was found to be more consistent with gauge observations over the Himalayas (e.g., Bhutan). Over the African continent, both conventional statistical measures (biases and root-mean-square-errors) and TCH method revealed PERSIANN to be more accurate than TRMM and other regional precipitation products such as ARC (version 2) and TAMSAT. Seasonal biases were still apparent in satellite-based/reanalysis precipitation estimates

  4. Increased Precipitation and Nitrogen Alter Shrub Architecture in a Desert Shrubland: Implications for Primary Production

    PubMed Central

    She, Weiwei; Zhang, Yuqing; Qin, Shugao; Wu, Bin; Bai, Yuxuan

    2016-01-01

    Shrublands are one of the major types of ecosystems in the desert regions of northern China, which is expected to be substantially more sensitive to global environmental changes, such as widespread nitrogen enrichment and precipitation changes, than other ecosystem types. However, the interactive effects of nitrogen and precipitation on them remain poorly understood. We conducted a fully factorial field experiment simulating three levels of precipitation (ambient, +20%, +40%) and with two levels of nitrogen deposition (ambient, 60 kg N ha-1 yr-1) in a desert shrubland in the Mu Us Desert of northern China. We used plant architectural traits (plant cover, volume, twig size and number) as proxies to predict aboveground net primary productivity (ANPP) of the dominant shrub (Artemisia ordosica Krasch), and assessed the responses of plant productivity and architectural traits to water and nitrogen addition. We found significant differences in twig size and number of A. ordosica under water and nitrogen treatments but not in shrub cover/volume, which suggest that twig size and number of the shrub species were more sensitive to environmental changes. The productivity of the overall community was sensitive to increased precipitation and nitrogen, and shrubs played a more important role than herbaceous plants in driving productivity in this ecosystem. Precipitation- and nitrogen-induced increases in vegetation production were positively associated with increases in twig size and number of the dominant shrub. Water addition enhanced the twig length of A. ordosica, while nitrogen addition resulted in increased twig density (the number of twigs per square meter). Water and nitrogen interacted to affect twig length, but not twig number and shrub ANPP. The trade-off, defined as negative covariance between twig size and number, was likely the mechanism underlying the responses of twig length and shrub ANPP to water and nitrogen interactions. Our results highlight the sensitivity

  5. Effects of precipitation changes on aboveground net primary production and soil respiration in a switchgrass field

    USDA-ARS?s Scientific Manuscript database

    This study attempted to test whether switchgrass aboveground net primary production (ANPP) responds to precipitation (PPT) changes in a double asymmetry pattern as framed by Knapp et al. (2016), and whether it is held true for other ecosystem processes such as soil respiration (SR). Data were colle...

  6. Legacies of precipitation fluctuations on primary production: Theory and data synthesis

    USDA-ARS?s Scientific Manuscript database

    Variability of aboveground net primary production (ANPP) of arid to sub-humid ecosystems displays a closer association with precipitation when considered across space, based on multiyear averages for different locations, than through time, based on year to year change at single locations. Here, we p...

  7. Legacies of precipitation fluctuations on primary production: theory and data synthesis

    USDA-ARS?s Scientific Manuscript database

    Variability of above-ground net primary production (ANPP) of arid to sub-humid ecosystems displays a closer association with precipitation when considered across space (based on multiyear averages for different locations) than through time (based on year-to-year change at single locations). Here, we...

  8. Extreme precipitation patterns and reductions of terrestrial ecosystem production across biomes

    Treesearch

    Yongguang Zhang; M. Susan Moran; Mark A. Nearing; Guillermo E. Ponce Campos; Alfredo R. Huete; Anthony R. Buda; David D. Bosch; Stacey A. Gunter; Stanley G. Kitchen; W. Henry McNab; Jack A. Morgan; Mitchel P. McClaran; Diane S. Montoya; Debra P.C. Peters; Patrick J. Starks

    2013-01-01

    Precipitation regimes are predicted to shift to more extreme patterns that are characterized by more heavy rainfall events and longer dry intervals, yet their ecological impacts on vegetation production remain uncertain across biomes in natural climatic conditions. This in situ study investigated the effects of these climatic conditions on aboveground net primary...

  9. Economics of recombinant antibody production processes at various scales: Industry-standard compared to continuous precipitation.

    PubMed

    Hammerschmidt, Nikolaus; Tscheliessnig, Anne; Sommer, Ralf; Helk, Bernhard; Jungbauer, Alois

    2014-06-01

    Standard industry processes for recombinant antibody production employ protein A affinity chromatography in combination with other chromatography steps and ultra-/diafiltration. This study compares a generic antibody production process with a recently developed purification process based on a series of selective precipitation steps. The new process makes two of the usual three chromatographic steps obsolete and can be performed in a continuous fashion. Cost of Goods (CoGs) analyses were done for: (i) a generic chromatography-based antibody standard purification; (ii) the continuous precipitation-based purification process coupled to a continuous perfusion production system; and (iii) a hybrid process, coupling the continuous purification process to an upstream batch process. The results of this economic analysis show that the precipitation-based process offers cost reductions at all stages of the life cycle of a therapeutic antibody, (i.e. clinical phase I, II and III, as well as full commercial production). The savings in clinical phase production are largely attributed to the fact that expensive chromatographic resins are omitted. These economic analyses will help to determine the strategies that are best suited for small-scale production in parallel fashion, which is of importance for antibody production in non-privileged countries and for personalized medicine.

  10. Comparison of global precipitation climatology products derived from ground- and satellite-based measurements

    NASA Astrophysics Data System (ADS)

    Liu, Zhong

    2014-11-01

    Satellite-based products increasingly take an important role in filling data gaps in data sparse regions around the world. In recent years, precipitation products that utilize multi-satellite and multi-sensor datasets have been gaining more popularity than products from a single sensor or satellite. Adjusted with gauge and ground radar data, satellitebased products have been significantly improved. However the history of satellite-based precipitation products is relatively short compared to the length of 30 years in the definition for climatology from the World Meteorological Organization (WMO). For example, the NASA/JAXA Tropical Rainfall Measuring Mission (TRMM) has been in operation for over 16 years since 1997. The length of TRMM is far shorter than those from ground observations, raising a question whether TRMM climatology products are good enough for research and applications. In this study, three climatologies derived from ground observations (Global Precipitation Climatology Centre (GPCC) and Willmott and Matsuura (WM)) and a blended product (the TRMM Multi-Satellite Precipitation Analysis (TMPA) monthly product or 3B43) are compared on a global scale to assess the performance and weaknesses of the TMPAderived climatology. Results show that the 3B43 climatology matches well with the two gauge-based climatologies in all seasons in terms of spatial distribution, zonal means as well as seasonal variations. However, high variations in rain rates are found in light rain regions such as the Sahara Desert. Large negative biases (3B43

  11. Global gridded precipitation over land: a description of the new GPCC First Guess Daily product

    NASA Astrophysics Data System (ADS)

    Schamm, K.; Ziese, M.; Becker, A.; Finger, P.; Meyer-Christoffer, A.; Schneider, U.; Schröder, M.; Stender, P.

    2013-08-01

    This paper describes the new "First Guess Daily" product of the Global Precipitation Climatology Centre (GPCC). The new product gives an estimate of the global daily precipitation gridded at a spatial resolution of 1° latitude by longitude. It is based on rain gauge data reported in near real-time via the Global Telecommunication System (GTS) and available about three to five days after the end of each observation month. In addition to the gridded daily precipitation totals in mm day-1, the standard deviation in mm day-1, the Kriging interpolation error in % and the number of measurements per grid cell are also encoded into the monthly netCDF product file and provided for all months since January 2009. Prior to their interpolation the measured precipitation values undergo a preliminary automatic quality control. For the calculation of the areal mean of the grid, anomalies are interpolated with ordinary block Kriging. This approach allows for a near real-time release. However, the purely GTS-based data processing lacks an intensive quality control as well as a high data density. Therefore the product is denoted as "First Guess", and DOI referenced under doi:10.5676/DWD_GPCC/FG_D_100. Besides the "First Guess Daily" product, two further products are under developement at GPCC ("Full Data Daily" and a merged satellite-gauge product), which will be based on all available daily data that have undergone a strict quality control. All GPCC products are available free of charge and provided via the GPCC webpage: ftp://ftp-anon.dwd.de/pub/data/gpcc/html/download_gate.html.

  12. Newly Released TRMM Version 7 Products, Other Precipitation Datasets and Data Services at NASA GES DISC

    NASA Technical Reports Server (NTRS)

    Liu, Zhong; Ostrenga, D.; Teng, W. L.; Trivedi, Bhagirath; Kempler, S.

    2012-01-01

    The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) is home of global precipitation product archives, in particular, the Tropical Rainfall Measuring Mission (TRMM) products. TRMM is a joint U.S.-Japan satellite mission to monitor tropical and subtropical (40 S - 40 N) precipitation and to estimate its associated latent heating. The TRMM satellite provides the first detailed and comprehensive dataset on the four dimensional distribution of rainfall and latent heating over vastly undersampled tropical and subtropical oceans and continents. The TRMM satellite was launched on November 27, 1997. TRMM data products are archived at and distributed by GES DISC. The newly released TRMM Version 7 consists of several changes including new parameters, new products, meta data, data structures, etc. For example, hydrometeor profiles in 2A12 now have 28 layers (14 in V6). New parameters have been added to several popular Level-3 products, such as, 3B42, 3B43. Version 2.2 of the Global Precipitation Climatology Project (GPCP) dataset has been added to the TRMM Online Visualization and Analysis System (TOVAS; URL: http://disc2.nascom.nasa.gov/Giovanni/tovas/), allowing online analysis and visualization without downloading data and software. The GPCP dataset extends back to 1979. Version 3 of the Global Precipitation Climatology Centre (GPCC) monitoring product has been updated in TOVAS as well. The product provides global gauge-based monthly rainfall along with number of gauges per grid. The dataset begins in January 1986. To facilitate data and information access and support precipitation research and applications, we have developed a Precipitation Data and Information Services Center (PDISC; URL: http://disc.gsfc.nasa.gov/precipitation). In addition to TRMM, PDISC provides current and past observational precipitation data. Users can access precipitation data archives consisting of both remote sensing and in-situ observations. Users can use these data

  13. Merging bottom-up and top-down precipitation products using a stochastic error model

    NASA Astrophysics Data System (ADS)

    Maggioni, Viviana; Massari, Christian; Brocca, Luca; Ciabatta, Luca

    2017-04-01

    Accurate quantitative precipitation estimation is of great importance for water resources management, agricultural planning, and forecasting and monitoring of natural hazards such as flash floods and landslides. In situ observations are limited around the Earth, especially in remote areas (e.g., complex terrain, dense vegetation), but currently available satellite precipitation products are able to provide global precipitation estimates with an accuracy that depends upon many factors (e.g., type of storms, temporal sampling, season etc…). Recently, Brocca et al. (2014) have proposed an alternative approach (i.e., SM2RAIN) that allows to estimate rainfall from space by using satellite soil moisture observations. In contrast with classical satellite precipitation products which sense the cloud properties to retrieve the instantaneous precipitation, this new bottom-up approach makes use of two consecutive soil moisture measurements for obtaining an estimate of the fallen precipitation within the interval between two satellite passes. As a result, the nature of the measurement is different and complementary to the one of classical precipitation products and could provide a different valid perspective to improve current satellite rainfall estimates via appropriate integration between the products (i.e., SM2RAIN plus a classical satellite rainfall product). However, whether SM2RAIN is able or not to improve the performance of any state-of-the-art satellite rainfall product is much dependent upon an adequate quantification and characterization of the relative errors of the products. In this study, the stochastic rainfall error model SREM2D (Hossain et al. 2006) is used for characterizing the retrieval error of both SM2RAIN and a state-of-the-art satellite precipitation product (i.e., 3B42RT). The error characterization serves for an optimal integration between SM2RAIN and 3B42RT for enhancing the capability of the resulting integrated product (i.e. SM2RAIN+3B42RT) in

  14. Global potential net primary production predicted from vegetation class, precipitation, and temperature

    SciTech Connect

    Del Grosso, Stephen; Parton, William; Stohlgren, Thomas; Zheng, Daolan; Bachelet, Dominique; Prince, Stephen; Hibbard, Kathy; Olson, Richard K

    2008-08-01

    Net primary production (NPP), the difference between CO2 fixed by photosynthesis and CO2 lost to autotrophic respiration, is one of the most important components of the carbon cycle. Our goal was to develop a simple regression model to estimate global NPP using climate and land cover data. Approximately 5600 global data points with observed mean annual NPP, land cover class, precipitation, and temperature were compiled. Precipitation was better correlated with NPP than temperature, and it explained much more of the variability in mean annual NPP for grass- or shrub-dominated systems (r2 = 0.68) than for tree-dominated systems (r2 = 0.39). For a given precipitation level, tree-dominated systems had significantly higher NPP (approximately 100-150 g C m(-2) yr(-1)) than non-tree-dominated systems. Consequently, previous empirical models developed to predict NPP based on precipitation and temperature (e.g., the Miami model) tended to overestimate NPP for non-tree-dominated systems. Our new model developed at the National Center for Ecological Analysis and Synthesis (the NCEAS model) predicts NPP for tree-dominated systems based on precipitation and temperature; but for non-tree-dominated systems NPP is solely a function of precipitation because including a temperature function increased model error for these systems. Lower NPP in non-tree-dominated systems is likely related to decreased water and nutrient use efficiency and higher nutrient loss rates from more frequent fire disturbances. Late 20th century aboveground and total NPP for global potential native vegetation using the NCEAS model are estimated to be approximately 28 Pg and approximately 46 Pg C/yr, respectively. The NCEAS model estimated an approximately 13% increase in global total NPP for potential vegetation from 1901 to 2000 based on changing precipitation and temperature patterns.

  15. Middle atmosphere NO/x/ production due to ion propulsion induced radiation belt proton precipitation

    NASA Technical Reports Server (NTRS)

    Aikin, A. C.; Jackman, C. H.

    1980-01-01

    The suggestion that keV Ar(+) resulting from ion propulsion operations during solar power satellite construction could cause energetic proton precipitation from the inner radiation belt is examined to determine if such precipitation could cause significant increases in middle atmosphere nitric oxide concentrations thereby adversely affecting stratospheric ozone. It is found that the initial production rate of NO (mole/cu cm-sec) at 50 km is 130 times that due to nitrous oxide reacting with excited oxygen. However, since the time required to empty the inner belt of protons is about 1 sec and short compared to the replenishment time due to neutron decay, precipitation of inner radiation belt protons will have no adverse atmospheric environmental effect.

  16. Uncertainties of Satellite-Based Daily Precipitation Products over the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Shen, Yan; Chen, Zhuoqi

    2013-04-01

    Satellite-based precipitation estimates is a major way to obtain the rainfall information especially in the sparse gauged areas of the Tibetan Plateau. Based on the gauge-based precipitation analysis in summer (JJA) for the period of 2005-2007, the performance of five satellite products are examined over the Tibetan Plateau in this research including 1) the CPC MORPHing products (CMORPH) of Joyce et al. (2004); 2) MW-adjusted IR products using Artificial Neural Network (PERSIANN, Hsu et al. 1997); 3) PDF matching MW-IR products NRL (Turk et al. 2004); 4) the gauge-adjusted MW-IR merged analysis of TRMM 3B42 (Huffman et al. 2007); and 5) its real-time version TRMM 3B42RT which is a MW-IR merged product without gauge adjustments (Huffman, et al. 2004). It shows that bias does exist in all the products with the smallest bias (relative bias) of -0.252 mm/d (-8.7%) observed by TRMM/3B42. Furthermore, following the research of Tian and Peters-Lidard (2010), three data ensemble methods of algorithm mean, one-outlier-removed algorithm mean and inverse-error-square weight, respectively, are used to generate the ensemble satellite-based precipitation estimates over the Tibetan Plateau. The ensemble data produced by the inverse-error-square weight has the best performance with bias (relative bias) of -0.06mm/d (-1.9%) in summer. The uncertainty of the satellite-based precipitation products is defined as the error square between each satellite estimate and the inverse-square-error-weight ensemble data. It indicates that the uncertainty is highly dependent on the rainfall rate and increased with the rainfall rate as an exponential function. Moreover, the uncertainty is seasonal dependency with the smallest in summer and largest in winter.

  17. Global gridded precipitation over land: a description of the new GPCC First Guess Daily product

    NASA Astrophysics Data System (ADS)

    Schamm, K.; Ziese, M.; Becker, A.; Finger, P.; Meyer-Christoffer, A.; Schneider, U.; Schröder, M.; Stender, P.

    2014-01-01

    This paper describes the new First Guess Daily product of the Global Precipitation Climatology Centre (GPCC). The new product gives an estimate of the global daily precipitation gridded at a spatial resolution of 1° latitude by 1° longitude. It is based on rain gauge data reported in near-real time via the Global Telecommunication System (GTS) and available about three to five days after the end of each observation month. In addition to the gridded daily precipitation totals in mm day-1, the standard deviation in mm day-1, the kriging interpolation error in % and the number of measurements per grid cell are also encoded into the monthly netCDF product file and provided for all months since January 2009. Prior to their interpolation, the measured precipitation values undergo a preliminary automatic quality control. For the calculation of the areal mean of the grid, anomalies are interpolated with ordinary block kriging. This approach allows for a near-real-time release. Therefore, the purely GTS-based data processing lacks an intensive quality control as well as a high data density and is denoted as First Guess. The daily data set is referenced under doi:10.5676/DWD_GPCC/FG_D_100. Two further products, the Full Data Daily and a merged satellite-gauge product, are currently under development at Deutscher Wetterdienst (DWD). These additional products will not be available in near-real time, but based on significantly more and strictly quality controlled observations. All GPCC products are provided free of charge via the GPCC webpage: ftp://ftp-anon.dwd.de/pub/data/gpcc/html/download_gate.html.

  18. Ecosystem net primary production responses to changes in precipitation using an annual integrated MODIS EVI

    NASA Astrophysics Data System (ADS)

    Ponce Campos, Guillermo Ernesto

    2011-12-01

    In this study, the relationship of above-ground net primary productivity (ANPP) with precipitation using the enhanced vegetation index (EVI) from satellite data as surrogate for ANPP was assessed. To use EVI as a proxy for ANPP we extracted the satellite data from areas with uniform vegetation in a 2x2 km area for the multi-site approach. In the multi-site analysis in the United States our results showed a strong exponential relationship between iEVI and annual precipitation across the sites and climate regimes studied. We found convergence of all sites toward common and maximum rain use efficiency under the water-limited conditions represented by the driest year at each site. Measures of inter-annual variability in iEVI with rainfall variation across biomes were similar to that reported by Knapp and Smith (2001) in which the more herbaceous dominant sites were found to be most sensitive to inter-annual variations in precipitation with no relationships found in woodland sites. The relationship was also evaluated in the southern hemisphere using a multi-site analysis with information from satellite TRMM for precipitation and MOD13Q1 from MODIS for EVI values at calendar and hydrologic year periods. The tested sites were located across the 6 major land cover types in Australia, obtained from MODIS MCD12Q1 product and used to compare the relationship across different biomes. The results showed significant agreement between the annual iEVI and annual precipitation across the biomes involved in this study showing non-significant differences between the calendar and hydrologic years for the 24 sites across different climatic conditions. At the regional scale we also assessed the ANPP-precipitation relationship across all of Australia. Precipitation data from TRMM was obtained at 0.25°x0.2°5 degrees spatial resolution and monthly temporal resolution and EVI values were obtained from the CGM (Climate Grid Modeling) MOD13C1-16-days and 5.6km temporal and spatial

  19. The new portfolio of global precipitation data products of the Global Precipitation Climatology Centre suitable to assess and quantify the global water cycle and resources

    NASA Astrophysics Data System (ADS)

    Schneider, Udo; Ziese, Markus; Meyer-Christoffer, Anja; Finger, Peter; Rustemeier, Elke; Becker, Andreas

    2016-10-01

    Precipitation plays an important role in the global energy and water cycle. Accurate knowledge of precipitation amounts reaching the land surface is of special importance for fresh water assessment and management related to land use, agriculture and hydrology, incl. risk reduction of flood and drought. High interest in long-term precipitation analyses arises from the needs to assess climate change and its impacts on all spatial scales. In this framework, the Global Precipitation Climatology Centre (GPCC) has been established in 1989 on request of the World Meteorological Organization (WMO). It is operated by Deutscher Wetterdienst (DWD, National Meteorological Service of Germany) as a German contribution to the World Climate Research Programme (WCRP). This paper provides information on the most recent update of GPCC's gridded data product portfolio including example use cases.

  20. Seasonal distribution of net primary production by functional groups in Chihuahuan Desert, and the role of seasonal precipitation

    USDA-ARS?s Scientific Manuscript database

    In hot deserts, precipitation is the principal driver for net primary production.  This study tested two hypotheses regarding aboveground net primary production (ANPP) and the effects of precipitation on ANPP in the Chihuahuan Desert, with emphasis on differences among seasons and among functional g...

  1. Comparison of Rainfall Products Derived From Trmm Microwave Imager and Precipitation Radar

    NASA Astrophysics Data System (ADS)

    Masunaga, H.; Iguchi, T.; Oki, R.; Kachi, M.

    Satellite remote sensing is an indispensable means of measuring and monitoring pre- cipitation on a global scale. The Tropical Rainfall Measurement Mission (TRMM) is continuing to make significant progress in helping us understand the global features of precipitation, particularly with the help of a pair of spaceborne microwave sen- sors, the TRMM Microwave Imager (TMI) and Precipitation Radar (PR). The TRMM standard products, however, are known to have a systematic inconsistency in mean monthly rainfall. To clarify the origin of this inconsistency, we investigate the zonal mean precipitation as well as the regional trends in the hydrometeor profiles in this paper in terms of the precipitation water content (PWC) and the precipitation water path (PWP) derived from the TMI profiling algorithm (reference number 2A12) and the PR profile (reference number 2A25). An excess of PR over TMI in near-surface PWC is identified in the midlatitudes especially in winter, whereas PWP exhibits a striking excess of TMI over PR around the tropical rainfall maximum. We presume that these inconsistencies arise from TMI underestimating the near-surface PWC in midlatitude winter and PR underestimating PWP in the tropics. This is supported by the contoured frequency by altitude diagrams (CFADs) as a function of PWC. Cor- relations between rain rate and PWC/PWP indicate that the TMI profiling algorithm tends to provide a larger rain rate than the PR profile under a given PWC or PWP, which exaggerates the excess by TMI and cancels the excess by PR through the con- version from precipitation water to rain rate. As a consequence, the disagreement in the rainfall products between TMI and PR is a combined result of the intrinsic bias originating from the different physical principles between TMI and PR measurements and the purely algorithmic bias inherent in the conversion from precipitation water to rain rate. The implications obtained in this study will be helpful for future develop- ment of

  2. Global Precipitation Measurment (GPM): Mission Data Products, Near-Realtime and Standard Research Products, Availability, Latency and Services

    NASA Astrophysics Data System (ADS)

    Stocker, E. F.; Kelley, O. A.; Stout, J. E.

    2014-12-01

    Effective 2 September 2014 all GPM data products from both instruments on thecore satellite as well as from microwave radiometers on constellation satellites became publicly available. Indeed products from the GPM MicrowaveImager as well as constellation microwave radiometers have been publiclyavailable since 14 July 2014. This paper will present summary informationabout the GPM data products including but not limited to their format, key parameters, collection periods, current status, and availability. As GPMhas both standard research products and near-realtime products (NRT) the paperwill present the information by these categories. For NRT products thelatency of their availability is also presented. Also presented is the processby which users obtain access to all the data products, standard and NRT, fromthe Precipitation Processing System (PPS). In conclusion the paper willdescribe services available from PPS fo5r ordering, subsetting, trending,and viewing the data products.

  3. The validation service of the hydrological SAF geostationary and polar satellite precipitation products

    NASA Astrophysics Data System (ADS)

    Puca, S.; Porcu, F.; Rinollo, A.; Vulpiani, G.; Baguis, P.; Balabanova, S.; Campione, E.; Ertürk, A.; Gabellani, S.; Iwanski, R.; Jurašek, M.; Kaňák, J.; Kerényi, J.; Koshinchanov, G.; Kozinarova, G.; Krahe, P.; Lapeta, B.; Lábó, E.; Milani, L.; Okon, L'.; Öztopal, A.; Pagliara, P.; Pignone, F.; Rachimow, C.; Rebora, N.; Roulin, E.; Sönmez, I.; Toniazzo, A.; Biron, D.; Casella, D.; Cattani, E.; Dietrich, S.; Di Paola, F.; Laviola, S.; Levizzani, V.; Melfi, D.; Mugnai, A.; Panegrossi, G.; Petracca, M.; Sanò, P.; Zauli, F.; Rosci, P.; De Leonibus, L.; Agosta, E.; Gattari, F.

    2014-04-01

    The development phase (DP) of the EUMETSAT Satellite Application Facility for Support to Operational Hydrology and Water Management (H-SAF) led to the design and implementation of several precipitation products, after 5 yr (2005-2010) of activity. Presently, five precipitation estimation algorithms based on data from passive microwave and infrared sensors, on board geostationary and sun-synchronous platforms, function in operational mode at the H-SAF hosting institute to provide near real-time precipitation products at different spatial and temporal resolutions. In order to evaluate the precipitation product accuracy, a validation activity has been established since the beginning of the project. A Precipitation Product Validation Group (PPVG) works in parallel with the development of the estimation algorithms with two aims: to provide the algorithm developers with indications to refine algorithms and products, and to evaluate the error structure to be associated with the operational products. In this paper, the framework of the PPVG is presented: (a) the characteristics of the ground reference data available to H-SAF (i.e. radar and rain gauge networks), (b) the agreed upon validation strategy settled among the eight European countries participating in the PPVG, and (c) the steps of the validation procedures. The quality of the reference data is discussed, and the efforts for its improvement are outlined, with special emphasis on the definition of a ground radar quality map and on the implementation of a suitable rain gauge interpolation algorithm. The work done during the H-SAF development phase has led the PPVG to converge into a common validation procedure among the members, taking advantage of the experience acquired by each one of them in the validation of H-SAF products. The methodology is presented here, indicating the main steps of the validation procedure (ground data quality control, spatial interpolation, up-scaling of radar data vs. satellite grid

  4. Evaluating Precipitation from Orbital Data Products of TRMM and GPM over the Indian Subcontinent

    NASA Astrophysics Data System (ADS)

    Jayaluxmi, I.; Kumar, D. N.

    2015-12-01

    The rapidly growing records of microwave based precipitation data made available from various earth observation satellites have instigated a pressing need towards evaluating the associated uncertainty which arise from different sources such as retrieval error, spatial/temporal sampling error and sensor dependent error. Pertaining to microwave remote sensing, most of the studies in literature focus on gridded data products, fewer studies exist on evaluating the uncertainty inherent in orbital data products. Evaluation of the latter are essential as they potentially cause large uncertainties during real time flood forecasting studies especially at the watershed scale. The present study evaluates the uncertainty of precipitation data derived from the orbital data products of the Tropical Rainfall Measuring Mission (TRMM) satellite namely the 2A12, 2A25 and 2B31 products. Case study results over the flood prone basin of Mahanadi, India, are analyzed for precipitation uncertainty through these three facets viz., a) Uncertainty quantification using the volumetric metrics from the contingency table [Aghakouchak and Mehran 2014] b) Error characterization using additive and multiplicative error models c) Error decomposition to identify systematic and random errors d) Comparative assessment with the orbital data from GPM mission. The homoscedastic random errors from multiplicative error models justify a better representation of precipitation estimates by the 2A12 algorithm. It can be concluded that although the radiometer derived 2A12 precipitation data is known to suffer from many sources of uncertainties, spatial analysis over the case study region of India testifies that they are in excellent agreement with the reference estimates for the data period considered [Indu and Kumar 2015]. References A. AghaKouchak and A. Mehran (2014), Extended contingency table: Performance metrics for satellite observations and climate model simulations, Water Resources Research, vol. 49

  5. Hydrologic evaluation of a Generalized Statistical Uncertainty Model for Satellite Precipitation Products

    NASA Astrophysics Data System (ADS)

    Sarachi, S.; Hsu, K. L.; Sorooshian, S.

    2014-12-01

    Development of satellite based precipitation retrieval algorithms and using them in hydroclimatic studies have been of great interest to hydrologists. It is important to understand the uncertainty associated with precipitation products and how they further contribute to the variability in stream flow simulation. In this study a mixture model of Generalized Normal Distribution and Gamma distribution (GND-G) is used to model the joint probability distribution of satellite-based (PERSIANN) and stage IV radar rainfall. The study area for constructing the uncertainty model covers a 15°×15°box of 0.25°×0.25° cells over the eastern United States for summer 2004 to 2009. Cells are aggregated in space and time to obtain data with different resolutions for the construction of the model's parameter space. This uncertainty model is evaluated using data from National Weather Service (NWS) Distributed Hydrologic Model Intercomparison Project - Phase 2 (DMIP 2) basin over Illinois River basin south of Siloam, OK. This data covers the time period of 2006 to 2008.The uncertainty range of precipitation is estimated. The impact of precipitation uncertainty to the stream flow estimation is demonstrated by Monte Carlo simulation of precipitation forcing in the Sacramento Soil Moisture Accounting (SAC-SMA) model. The results show that using precipitation along with its uncertainty distribution as forcing to SAC-SMA make it possible to have an estimation of the uncertainty associated with the stream flow simulation ( in this case study %90 confidence interval is used). The mean of this stream flow confidence interval is compared to the reference stream flow for evaluation of the model and the results show that this method helps to better estimate the variability of the stream flow simulation along with its statistics e.g. percent bias and root mean squared error.

  6. New and Updated Gridded Analysis Products provided by the Global Precipitation Climatology Centre (GPCC)

    NASA Astrophysics Data System (ADS)

    Ziese, Markus; Schneider, Udo; Meyer-Christoffer, Anja; Finger, Peter; Schamm, Kirstin; Rustemeier, Elke; Becker, Andreas

    2016-04-01

    Since its start in 1989 the Global Precipitation Climatology Centre (GPCC) performs global analyses of monthly precipitation for the earth's land-surface on the basis of in-situ measurements. Meanwhile, the data set has continuously grown both in temporal coverage (original start of the evaluation period was 1986), as well as extent and quality of the underlying data base. The high spatio-temporal variability of precipitation requires an accordingly high density of measurement data. Data collected from national meteorological and hydrological services are the core of the GPCC data base, supported by global and regional data collections. Also the GPCC receives SYNOP and CLIMAT reports via WMO-GTS, which are mainly applied for near-real-time products. A high quality control effort is undertaken to remove miscoded and temporal or spatial dislocated data before entry into the GPCC archive, serving the basis for further interpolation and product generation. The GPCC archive holds records from almost 100 000 stations, among those three quarters with records long enough to serve the data basis of the GPCC suite of global precipitation products, comprising near-real-time as well as non-real-time products. Near-real-time products are the 'First Guess Monthly', 'First Guess Daily', 'Monitoring Product' and 'GPCC Drought Index'. These products are based on WMO-GTS data, e.g., SYNOP and CLIMAT reports and monthly totals calculated at CPC. Non-real-time products are the 'Full Data Monthly', 'Full Data Daily', 'Climatology', and 'HOMPRA-Europe'. Data from national meteorological and hydrological services and regional and global data collections are mainly used to calculate these products. Also WMO-GTS data are used if no other data are available. The majority of the products were released in an updated version, but 'Full Data Daily' and HOMPRA-Europe' are new products provided the first time. 'Full Data Daily' is a global analysis of daily precipitation totals from 1988 to 2013

  7. Current status of the dual-frequency precipitation radar on the global precipitation measurement core spacecraft and the new version of GPM standard products

    NASA Astrophysics Data System (ADS)

    Furukawa, K.; Nio, T.; Konishi, T.; Masaki, T.; Kubota, T.; Oki, R.; Iguchi, T.

    2016-10-01

    The Dual-frequency Precipitation Radar (DPR) on the Global Precipitation Measurement (GPM) core satellite was developed by Japan Aerospace Exploration Agency (JAXA) and National Institute of Information and Communications Technology (NICT). The objective of the GPM mission is to observe global precipitation more frequently and accurately. The GPM core satellite is a joint product of National Aeronautics and Space Administration (NASA), JAXA and NICT. NASA developed the satellite bus and the GPM Microwave Imager (GMI), and JAXA and NICT developed the DPR. The inclination of the GPM core satellite is 65 degrees, and the nominal flight altitude is 407 km. The non-sunsynchronous circular orbit is necessary for measuring the diurnal change of rainfall. The DPR consists of two radars, which are Ku-band precipitation radar (KuPR) and Ka-band precipitation radar (KaPR). GPM core observatory was successfully launched by H2A launch vehicle on Feb. 28, 2014. DPR keeps its performances on orbit after launch. DPR products were released to the public on Sep. 2, 2014. JAXA is continuing DPR trend monitoring, calibration and validation operations to confirm that DPR keeps its function and performance on orbit. JAXA have started to provide new version (Version 4) of GPM standard products on March 3, 2016. Various improvements of the DPR algorithm were implemented in the Version 4 product. Moreover, the latent heat product based on the Spectral Latent Heating (SLH) algorithm is available since Version 4 product. Current orbital operation status of the GPM/DPR and highlights of the Version 4 product are reported.

  8. Primary Productivity and Precipitation-Use Efficiency in Temperate Grassland in the Loess Plateau of China.

    PubMed

    Jia, Xiaoxu; Xie, Baoni; Shao, Ming'an; Zhao, Chunlei

    2015-01-01

    Clarifying spatial variations in aboveground net primary productivity (ANPP) and precipitation-use efficiency (PUE) of grasslands is critical for effective prediction of the response of terrestrial ecosystem carbon and water cycle to future climate change. Though the combination use of remote sensing products and in situ ANPP measurements, we quantified the effects of climatic [mean annual precipitation (MAP) and precipitation seasonal distribution (PSD)], biotic [leaf area index (LAI)] and abiotic [slope gradient, aspect, soil water storage (SWS) and other soil physical properties] factors on the spatial variations in ANPP and PUE across different grassland types (i.e., meadow steppe, typical steppe and desert steppe) in the Loess Plateau. Based on the study, ANPP increased exponentially with MAP for the entire temperate grassland; suggesting that PUE increased with increasing MAP. Also PSD had a significant effect on ANPP and PUE; where more even PSD favored higher ANPP and PUE. Then MAP, more than PSD, explained spatial variations in typical steppe and desert steppe. However, PSD was the dominant driving factor of spatial variations in ANPP of meadow steppe. This suggested that in terms of spatial variations in ANPP of meadow steppe, change in PSD due to climate change was more important than that in total annual precipitation. LAI explained 78% of spatial PUE in the entire Loess Plateau temperate grassland. As such, LAI was the primary driving factor of spatial variations in PUE. Although the effect of SWS on ANPP and PUE was significant, it was nonetheless less than that of precipitation and vegetation. We therefore concluded that changes in vegetation structure and consequently in LAI and/or altered pattern of seasonal distribution of rainfall due to global climate change could significantly influence ecosystem carbon and water cycle in temperate grasslands.

  9. Utilizing Satellite Precipitation Products to Understand the Link Between Climate Variability and Malaria

    NASA Astrophysics Data System (ADS)

    Maggioni, V.; Mousam, A.; Delamater, P. L.; Cash, B. A.; Quispe, A.

    2015-12-01

    Malaria is a public health threat to people globally leading to 198 million cases and 584,000 deaths annually. Outbreaks of vector borne diseases such as malaria can be significantly impacted by climate variables such as precipitation. For example, an increase in rainfall has the potential to create pools of water that can serve as breeding locations for mosquitos. Peru is a country that is currently controlling malaria, but has not been able to completely eliminate the disease. Despite the various initiatives in order to control malaria - including regional efforts to improve surveillance, early detection, prompt treatment, and vector management - malaria cases in Peru have risen between 2011 and 2014. The purpose of this study is to test the hypothesis that climate variability plays a fundamental role in malaria occurrence over a 12-year period (2003-2014) in Peru. When analyzing climate variability, it is important to obtain high-quality, high-resolution data for a time series long enough to draw conclusion about how climate variables have been and are changing. Remote sensing is a powerful tool for measuring and monitoring climate variables continuously in time and space. A widely used satellite-based precipitation product, the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA), available globally since 1998, was used to obtain 3-hourly data with a spatial resolution of 0.25° x 0.25°. The precipitation data was linked to weekly (2003-2014) malaria cases collected by health centers and available at a district level all over Peru to investigate the relationship between precipitation and the seasonal and annual variations in malaria incidence. Further studies will incorporate additional climate variables such as temperature, humidity, soil moisture, and surface pressure from remote sensing data products and climate models. Ultimately, this research will help us to understand if climate variability impacts malaria incidence

  10. Primary Productivity and Precipitation-Use Efficiency in Temperate Grassland in the Loess Plateau of China

    PubMed Central

    Jia, Xiaoxu; Xie, Baoni; Shao, Ming’an; Zhao, Chunlei

    2015-01-01

    Clarifying spatial variations in aboveground net primary productivity (ANPP) and precipitation-use efficiency (PUE) of grasslands is critical for effective prediction of the response of terrestrial ecosystem carbon and water cycle to future climate change. Though the combination use of remote sensing products and in situ ANPP measurements, we quantified the effects of climatic [mean annual precipitation (MAP) and precipitation seasonal distribution (PSD)], biotic [leaf area index (LAI)] and abiotic [slope gradient, aspect, soil water storage (SWS) and other soil physical properties] factors on the spatial variations in ANPP and PUE across different grassland types (i.e., meadow steppe, typical steppe and desert steppe) in the Loess Plateau. Based on the study, ANPP increased exponentially with MAP for the entire temperate grassland; suggesting that PUE increased with increasing MAP. Also PSD had a significant effect on ANPP and PUE; where more even PSD favored higher ANPP and PUE. Then MAP, more than PSD, explained spatial variations in typical steppe and desert steppe. However, PSD was the dominant driving factor of spatial variations in ANPP of meadow steppe. This suggested that in terms of spatial variations in ANPP of meadow steppe, change in PSD due to climate change was more important than that in total annual precipitation. LAI explained 78% of spatial PUE in the entire Loess Plateau temperate grassland. As such, LAI was the primary driving factor of spatial variations in PUE. Although the effect of SWS on ANPP and PUE was significant, it was nonetheless less than that of precipitation and vegetation. We therefore concluded that changes in vegetation structure and consequently in LAI and/or altered pattern of seasonal distribution of rainfall due to global climate change could significantly influence ecosystem carbon and water cycle in temperate grasslands. PMID:26295954

  11. Preparation for GPM: Development of a New Near Real-time High Resolution Multi-sensor Precipitation Estimation Product Based on Analyzing the Existing Precipitation Estimation Techniques

    NASA Astrophysics Data System (ADS)

    Behrangi, A.; Sorooshian, S.; Hsu, K.; Bellerby, T. J.; Huffman, G. J.; Lambrigtsen, B.

    2010-12-01

    By analyzing the existing precipitation estimation techniques, a new near real-time multi-platform multi-sensor satellite precipitation estimation algorithm is developed which incorporates cloud classification techniques to effectively adjust microwave (MW) precipitation intensities as advected forward/backward in time. The technique which will significantly benefit from the future Global Precipitation Measurement (GPM) mission consists of three main steps: The first step uses successive IR images to calculate cloud motion streamlines from a 2D cloud tracking algorithm, explicitly incorporating the effect of cloud motion, growth, deformation and dispersal. The second step classifies cloudy pixels into a number of predefined clusters using several infrared-extracted cloud features representing radiative, textural and dynamic properties of clouds. The algorithm is also capable to readily incorporate multi-spectral information to improve the cloud classification system. By calculating the precipitation features in each class, MW precipitation intensity is adjusted as advected between two consecutive microwave overpasses, both forward-only and forward- backward. The technique was developed and tested at 0.08-degree latitude/longitude resolution every 30 minutes and evaluated over the conterminous United States. The performance of the algorithm compared favorably with several existing products which will be discussed.

  12. Effect of structural characteristics of corncob hemicelluloses fractionated by graded ethanol precipitation on furfural production.

    PubMed

    Li, Huiling; Dai, Qingqing; Ren, Junli; Jian, Longfei; Peng, Feng; Sun, Runcang; Liu, Guoliang

    2016-01-20

    In the present study, a graded ethanol precipitation technique was employed to obtain hemicelluloses from the alkali-extracted corncob liquid. The relationship between the structural characteristics of alkali-soluble corncob hemicelluloses and the production of furfural was investigated by a heterogeneous process in a biphasic system. Results showed that alkali-soluble corncob hemicelluloses mainly consisted of glucuronoarabinoxylans and L-arabino-(4-O-methylglucurono)-D-xylans, and the drying way had less influence on the sugar composition, molecular weights and the functional groups of hemicelluloses obtained by the different ethanol concentration precipitation except for the thermal property, the amorphous structure and the ability for the furfural production. Furthermore, alkali-soluble corncob hemicelluloses with higher xylose content, lower branch degree, higher polydispersity and crystallinity contributed to the furfural production. A highest furfural yield of 45.41% with the xylose conversion efficiency of 99.06% and the furfural selectivity of 45.84% was obtained from the oven-dried hemicelluloses precipitated at the 30% (v/v) ethanol concentration. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Data Analysis of GPM Constellation Satellites-IMERG and ERA-Interim precipitation products over West of Iran

    NASA Astrophysics Data System (ADS)

    Sharifi, Ehsan; Steinacker, Reinhold; Saghafian, Bahram

    2016-04-01

    Precipitation is a critical component of the Earth's hydrological cycle. The primary requirement in precipitation measurement is to know where and how much precipitation is falling at any given time. Especially in data sparse regions with insufficient radar coverage, satellite information can provide a spatial and temporal context. Nonetheless, evaluation of satellite precipitation is essential prior to operational use. This is why many previous studies are devoted to the validation of satellite estimation. Accurate quantitative precipitation estimation over mountainous basins is of great importance because of their susceptibility to hazards. In situ observations over mountainous areas are mostly limited, but currently available satellite precipitation products can potentially provide the precipitation estimation needed for meteorological and hydrological applications. One of the newest and blended methods that use multi-satellites and multi-sensors has been developed for estimating global precipitation. The considered data set known as Integrated Multi-satellitE Retrievals (IMERG) for GPM (Global Precipitation Measurement) is routinely produced by the GPM constellation satellites. Moreover, recent efforts have been put into the improvement of the precipitation products derived from reanalysis systems, which has led to significant progress. One of the best and a worldwide used model is developed by the European Centre for Medium Range Weather Forecasts (ECMWF). They have produced global reanalysis daily precipitation, known as ERA-Interim. This study has evaluated one year of precipitation data from the GPM-IMERG and ERA-Interim reanalysis daily time series over West of Iran. IMERG and ERA-Interim yield underestimate the observed values while IMERG underestimated slightly and performed better when precipitation is greater than 10mm. Furthermore, with respect to evaluation of probability of detection (POD), threat score (TS), false alarm ratio (FAR) and probability

  14. Bias correction of satellite precipitation products for flood forecasting application at the Upper Mahanadi River Basin in Eastern India

    NASA Astrophysics Data System (ADS)

    Beria, H.; Nanda, T., Sr.; Chatterjee, C.

    2015-12-01

    High resolution satellite precipitation products such as Tropical Rainfall Measuring Mission (TRMM), Climate Forecast System Reanalysis (CFSR), European Centre for Medium-Range Weather Forecasts (ECMWF), etc., offer a promising alternative to flood forecasting in data scarce regions. At the current state-of-art, these products cannot be used in the raw form for flood forecasting, even at smaller lead times. In the current study, these precipitation products are bias corrected using statistical techniques, such as additive and multiplicative bias corrections, and wavelet multi-resolution analysis (MRA) with India Meteorological Department (IMD) gridded precipitation product,obtained from gauge-based rainfall estimates. Neural network based rainfall-runoff modeling using these bias corrected products provide encouraging results for flood forecasting upto 48 hours lead time. We will present various statistical and graphical interpretations of catchment response to high rainfall events using both the raw and bias corrected precipitation products at different lead times.

  15. A Stochastic Technique for Error Correction and Spatial Downscaling of Global Gridded Precipitation Products

    NASA Astrophysics Data System (ADS)

    Seyyedi, H.; Kaheil, Y.; Anagnostou, E. N.; McCollum, J.; Beighley, E.

    2013-12-01

    Deriving flood maps requires an accurate characterization of precipitation variability at high spatio-temporal resolution. Most of the available global-scale gridded precipitation products are available at resolutions (e.g., 25 km) not directly applicable to flood modeling. An error correction and spatial downscaling method based on a two-dimensional satellite rainfall error model (SREM2D) is tested in this study based on a long-term (2001-2010) dataset. Specifically, the model is applied on two rainfall datasets: a satellite precipitation product (TRMM-3B42.V7 at 0.25 degree) and a global land-atmosphere re-analysis product (GLDAS-CLM at 1 degree), to produce error corrected rainfall ensembles at 0.05 degree spatial resolution. The NCEP hourly, 4-km resolution multi-sensor precipitation product (WSR-88D stage IV gauge-adjusted radar-rainfall product) is used as the reference rainfall dataset. The Hillslope River Routing (HRR) hydrologic model is forced with the downscaled ensemble rainfall data to produce an ensemble of runoff values. The Susquehanna River basin is the study area, consisting of 1000 sub-basins ranging from 39 to 67,000 square kilometers including complex terrain and high latitude locations. There are 437 significant storm events selected over the study area based on the 10-year database. The analysis performed is based on 60 percent of events in each season kept for model calibration and 40 percent for validation. The statistical analysis consists of two parts: (1) evaluation of error metrics (relative standard deviation and efficiency coefficient) to quantify improvements in rainfall and runoff simulations as function of basin size and storm severity, and (2) ensemble verification (exceedance probability and mean uncertainty ratio) of the rainfall and runoff ensembles to assess the accuracy of the ensemble-based uncertainty characterization. The study investigates how well the ensemble of downscaled and error-corrected rainfall data performs

  16. Increasing precipitation event size increases aboveground net primary productivity in a semi-arid grassland.

    PubMed

    Heisler-White, Jana L; Knapp, Alan K; Kelly, Eugene F

    2008-11-01

    Water availability is the primary constraint to aboveground net primary productivity (ANPP) in many terrestrial biomes, and it is an ecosystem driver that will be strongly altered by future climate change. Global circulation models predict a shift in precipitation patterns to growing season rainfall events that are larger in size but fewer in number. This "repackaging" of rainfall into large events with long intervening dry intervals could be particularly important in semi-arid grasslands because it is in marked contrast to the frequent but small events that have historically defined this ecosystem. We investigated the effect of more extreme rainfall patterns on ANPP via the use of rainout shelters and paired this experimental manipulation with an investigation of long-term data for ANPP and precipitation. Experimental plots (n = 15) received the long-term (30-year) mean growing season precipitation quantity; however, this amount was distributed as 12, six, or four events applied manually according to seasonal patterns for May-September. The long-term mean (1940-2005) number of rain events in this shortgrass steppe was 14 events, with a minimum of nine events in years of average precipitation. Thus, our experimental treatments pushed this system beyond its recent historical range of variability. Plots receiving fewer, but larger rain events had the highest rates of ANPP (184 +/- 38 g m(-2)), compared to plots receiving more frequent rainfall (105 +/- 24 g m(-2)). ANPP in all experimental plots was greater than long-term mean ANPP for this system (97 g m(-2)), which may be explained in part by the more even distribution of applied rain events. Soil moisture data indicated that larger events led to greater soil water content and likely permitted moisture penetration to deeper in the soil profile. These results indicate that semi-arid grasslands are capable of responding immediately and substantially to forecast shifts to more extreme precipitation patterns.

  17. Comparison and evaluation of high resolution precipitation estimation products in Urmia Basin-Iran

    NASA Astrophysics Data System (ADS)

    Ghajarnia, N.; Liaghat, A.; Daneshkar Arasteh, P.

    2015-05-01

    This study focuses on the comparison and evaluation of six daily 0.25° × 0.25° high resolution precipitation data sets (PERSIANN, CMORPH-RAW, CMORPH-CRT, TMPA-RT, TMPA-V7 and APHRODITE). The comparison is performed during years 2000 till 2011 in Urmia basin of Iran and the local daily rainfall gauge observations are considered as the reference data set. Several statistical, categorical and graphical evaluation techniques are used to compare and evaluate the product performances and quantify their biases from reference data. APHRODITE and TMPA-V7, by benefiting from gauge observations during their adjustment procedures present better estimations while among near real-time products, PERSIANN is able to remarkably outperform other estimations. Both CMORPH products has shown to have great overestimation (more than 200%) over the observations while PERSIANN and TMPA-RT tend to underestimate rainfall on average about 26% and 78% respectively. TMPA-V7 and APHRODITE also overestimate observations about 26 and 3 percentages. Compared to near real-time version of products, TMPA-V7 has succeeded to significantly improve TMPA-RT performance while CMORPH-CRT has completely unsuccessful in its mission. Although all rainfall estimation products are characterized by considerable biases in comparison to the gauge observations, detailed analysis indicate that some of them have the capability of becoming a valuable source of high resolution precipitation estimation data set, especially over purely gauged areas.

  18. Desalination and hydrogen, chlorine, and sodium hydroxide production via electrophoretic ion exchange and precipitation.

    PubMed

    Shkolnikov, Viktor; Bahga, Supreet S; Santiago, Juan G

    2012-08-28

    We demonstrate and analyze a novel desalination method which works by electrophoretically replacing sodium and chloride in feed salt water with a pair of ions, calcium and carbonate, that react and precipitate out. The resulting calcium carbonate precipitate is benign to health, and can be filtered or settled out, yielding low ionic strength product water. The ion exchange and precipitation employs self-sharpening interfaces induced by movement of multiple ions in an electric field to prevent contamination of the product water. Simultaneously, the electrolysis associated with the electromigration produces hydrogen gas, chlorine gas, and sodium hydroxide. We conducted an experimental study of this method's basic efficacy to desalinate salt water from 100 to 600 mol m(-3) sodium chloride. We also present physicochemical models of the process, and analyze replacement reagents consumption, permeate recovery ratio, and energy consumption. We hypothesize that the precipitate can be recycled back to replacement reagents using the well-known, commercially implemented Solvay process. We show that the method's permeate recovery ratio is 58% to 46%, which is on par with that of reverse osmosis. We show that the method's energy consumption requirement over and above that necessary to generate electrolysis is 3 to 10 W h l(-1), which is on par with the energy consumed by state-of-the-art desalination methods. Furthermore, the method operates at ambient temperature and pressure, and uses no specialized membranes. The process may be feasible as a part of a desalination-co-generation facility: generating fresh water, hydrogen and chlorine gas, and sodium hydroxide.

  19. Evaluation of Reanalysis and TRMM Products Using a New Gauge-Based Analysis of Daily Precipitation over China

    NASA Astrophysics Data System (ADS)

    Zhao, T.; Yatagai, A. I.; Aili, K.

    2010-12-01

    In this study, a new gauge-based analysis of daily precipitation (regard as observations) developed by the ‘Asian Precipitation Highly-Resolved Observational Data Integration Towards Evaluation of the Water Resources (APHRODITE)’ project will be used to validate the precipitation products from NCEP-NCAR, NCEP-DOE, ERA-40 and JRA-25 reanalysis over China, a typical monsoon region in East Asia for a 25-year period from 1979 to 2003. The applicability represented by reanalyzed precipitation in climate research will be analyzed through multi-statistical diagnostic analysis methods on different spatio-temporal scales, especially in seasonal and interannual variation over China. At same time, we developed the 0.25-degree daily precipitation data from 756 Chinese stations using the APHRODITE data analysis system from 1960 to 2008. And such products were used to evaluate the Tropical Rainfall Measuring Mission (TRMM) merged high quality (HQ)/infrared (IR) precipitation over south China, especially in the Yangtze-Huai River Valley of China during the periods 1998-2008. The main results about this study reveal that the ERA-40 and JRA-25 are better than NCRP-NCAR and NCEP-DOE to describe the spatial distribution and temporal variation represented by observations in most regions of China, but the NCEP-DOE has a better ability to represent the variation of Meiyu belt in the Yangtze-Huai River Valley of China. With regard to the magnitude of the precipitation difference between the reanalyes and the observations, the JRA-25 is closer to the observed precipitation than others over most domains. The comparison indicates that the TRMM product describes well the observed precipitation and its seasonal and annual variations for most of China, but has some limitations in estimating extreme precipitation. Therefore, the TRMM precipitation product should be used with caution as reference data to detect errors in gauge observations in the absence other data.

  20. Mesospheric NO2 production due to relativistic electron precipitation from 2007 till 2011

    NASA Astrophysics Data System (ADS)

    Friederich, Felix; Sinnhuber, Miriam; Funke, Bernd; von Clarmann, Thomas; Stiller, Gabriele; Orphal, Johannes

    2013-04-01

    Electrons of the radiation belts and the aurora can precipitate into the Earth's atmosphere. Depending on their energy they intrude into different altitudes and can excitate, ionize, and dissociate molecular nitrogen. Subsequent (ion-)chemical reactions result in an effective NOx-production (NOx=NO+NO2). NOx is produced mostly by auroral electrons in the thermosphere at ca. 110 km altitude. But relativistic electrons from the radiation belts can also reach the stratosphere. However, in the stratosphere and lower mesosphere, no direct NOx-production due to electron precipitation has been detected yet. We use NO2 observations from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on Envisat in the altitude range from 40 km to 60 km in order to search for direct NOx-production. We show that the AP index correlates with the nighttime NO2 abundance between 44 km and 54 km altitude at 65±5°N geomagnetic latitude. At these altitudes the NO2 ratio of nighttime NOx is between 80 % and 100 %. Because of the correlation between AP index and nighttime NO2, we conclude, that there is direct NOx-production caused by relativistic electrons about 0.5 ppb at the most.

  1. Building Capacity for Production of Gridded Precipitation Products in the East Africa Community

    NASA Astrophysics Data System (ADS)

    Budde, M. E.; Verdin, J. P.; Galu, G.; Magadzire, T.; Pedreros, D. H.; Funk, C. C.; Husak, G. J.; Peterson, P.; Landsfeld, M. F.; White, L.

    2014-12-01

    The Famine Early Warning Systems Network (FEWS NET) participates in the Group on Earth Observations' Global Agricultural Monitoring (GEOGLAM) activity in a number of ways. Recently, important progress has been made in meeting the need for improved precipitation data sets in East Africa. This has been done through capacity building activities with national meteorological and hydrological services (NMHS) in the region, carried out in partnership with the IGAD Climate Prediction and Applications Center (ICPAC), and with support from the WMO Office for Eastern and Southern Africa. Through a series of regional gatherings and individual country workshops, scientists from the NMHS have been introduced to the Climate Hazards Group Infrared Precipitation with Stations (CHIRPS) rainfall data set and the GeoCLIM software tool. The CHIRPS data set was developed by USGS and the University of California, Santa Barbara, by blending NOAA geostationary thermal infrared imagery with station observations, using robust geostatistical methods. The core data set consists of pentadal (5-daily) accumulations from 1981-2014 at 0.05 degree spatial resolution, between +/- 50 degrees latitude. The GeoCLIM software can operate on the CHIRPS to map the Standardized Precipitation Index, trends, anomalies, isohyets, and other types of spatio-temporal features. It can also produce new gridded rainfall data sets by geostatistical blending of station observations with existing rainfall grids. NMHS scientists have applied this latter capability to produce best-available national and regional gridded rainfall time-series for 1981-2014 for the East Africa Community (EAC). These data are a fundamental resource for the USAID-EAC climate change adaptation project known by the acronym PREPARED. They incorporate a larger and more complete collection of station observations than ever before. Further work is ongoing at the NMHS to take advantage of the data management capabilities of GeoCLIM, and incorporate

  2. Enhanced interannual precipitation variability increases plant functional diversity that in turn ameliorates negative impact on productivity

    USDA-ARS?s Scientific Manuscript database

    Although precipitation interannual variability is projected to increase due to climate change, effects of changes in precipitation variance have received considerable less attention than effects of changes in the mean state of climate. Interannual precipitation variability effects on functional dive...

  3. Evaluation of NASA's MERRA Precipitation Product in Reproducing the Observed Trend and Distribution of Extreme Precipitation Events in the United States

    NASA Technical Reports Server (NTRS)

    Ashouri, Hamed; Sorooshian, Soroosh; Hsu, Kuo-Lin; Bosilovich, Michael G.; Lee, Jaechoul; Wehner, Michael F.; Collow, Allison

    2016-01-01

    This study evaluates the performance of NASA's Modern-Era Retrospective Analysis for Research and Applications (MERRA) precipitation product in reproducing the trend and distribution of extreme precipitation events. Utilizing the extreme value theory, time-invariant and time-variant extreme value distributions are developed to model the trends and changes in the patterns of extreme precipitation events over the contiguous United States during 1979-2010. The Climate Prediction Center (CPC) U.S.Unified gridded observation data are used as the observational dataset. The CPC analysis shows that the eastern and western parts of the United States are experiencing positive and negative trends in annual maxima, respectively. The continental-scale patterns of change found in MERRA seem to reasonably mirror the observed patterns of change found in CPC. This is not previously expected, given the difficulty in constraining precipitation in reanalysis products. MERRA tends to overestimate the frequency at which the 99th percentile of precipitation is exceeded because this threshold tends to be lower in MERRA, making it easier to be exceeded. This feature is dominant during the summer months. MERRA tends to reproduce spatial patterns of the scale and location parameters of the generalized extreme value and generalized Pareto distributions. However, MERRA underestimates these parameters, particularly over the Gulf Coast states, leading to lower magnitudes in extreme precipitation events. Two issues in MERRA are identified: 1) MERRA shows a spurious negative trend in Nebraska and Kansas, which is most likely related to the changes in the satellite observing system over time that has apparently affected the water cycle in the central United States, and 2) the patterns of positive trend over the Gulf Coast states and along the East Coast seem to be correlated with the tropical cyclones in these regions. The analysis of the trends in the seasonal precipitation extremes indicates that

  4. Evaluation of NASA's MERRA Precipitation Product in Reproducing the Observed Trend and Distribution of Extreme Precipitation Events in the United States

    NASA Technical Reports Server (NTRS)

    Ashouri, Hamed; Sorooshian, Soroosh; Hsu, Kuo-Lin; Bosilovich, Michael G.; Lee, Jaechoul; Wehner, Michael F.; Collow, Allison

    2016-01-01

    This study evaluates the performance of NASA's Modern-Era Retrospective Analysis for Research and Applications (MERRA) precipitation product in reproducing the trend and distribution of extreme precipitation events. Utilizing the extreme value theory, time-invariant and time-variant extreme value distributions are developed to model the trends and changes in the patterns of extreme precipitation events over the contiguous United States during 1979-2010. The Climate Prediction Center (CPC) U.S.Unified gridded observation data are used as the observational dataset. The CPC analysis shows that the eastern and western parts of the United States are experiencing positive and negative trends in annual maxima, respectively. The continental-scale patterns of change found in MERRA seem to reasonably mirror the observed patterns of change found in CPC. This is not previously expected, given the difficulty in constraining precipitation in reanalysis products. MERRA tends to overestimate the frequency at which the 99th percentile of precipitation is exceeded because this threshold tends to be lower in MERRA, making it easier to be exceeded. This feature is dominant during the summer months. MERRA tends to reproduce spatial patterns of the scale and location parameters of the generalized extreme value and generalized Pareto distributions. However, MERRA underestimates these parameters, particularly over the Gulf Coast states, leading to lower magnitudes in extreme precipitation events. Two issues in MERRA are identified: 1) MERRA shows a spurious negative trend in Nebraska and Kansas, which is most likely related to the changes in the satellite observing system over time that has apparently affected the water cycle in the central United States, and 2) the patterns of positive trend over the Gulf Coast states and along the East Coast seem to be correlated with the tropical cyclones in these regions. The analysis of the trends in the seasonal precipitation extremes indicates that

  5. Evaluation of NASA’s MERRA Precipitation Product in Reproducing the Observed Trend and Distribution of Extreme Precipitation Events in the United States

    SciTech Connect

    Ashouri, Hamed; Sorooshian, Soroosh; Hsu, Kuo-Lin; Bosilovich, Michael G.; Lee, Jaechoul; Wehner, Michael F.; Collow, Allison

    2016-02-03

    This study evaluates the performance of NASA's Modern-Era Retrospective Analysis for Research and Applications (MERRA) precipitation product in reproducing the trend and distribution of extreme precipitation events. Utilizing the extreme value theory, time-invariant and time-variant extreme value distributions are developed to model the trends and changes in the patterns of extreme precipitation events over the contiguous United States during 1979-2010. The Climate Prediction Center (CPC)U.S.Unified gridded observation data are used as the observational dataset. The CPC analysis shows that the eastern and western parts of the United States are experiencing positive and negative trends in annual maxima, respectively. The continental-scale patterns of change found in MERRA seem to reasonably mirror the observed patterns of change found in CPC. This is not previously expected, given the difficulty in constraining precipitation in reanalysis products. MERRA tends to overestimate the frequency at which the 99th percentile of precipitation is exceeded because this threshold tends to be lower in MERRA, making it easier to be exceeded. This feature is dominant during the summer months. MERRAtends to reproduce spatial patterns of the scale and location parameters of the generalized extreme value and generalized Pareto distributions. However, MERRA underestimates these parameters, particularly over the Gulf Coast states, leading to lower magnitudes in extreme precipitation events. Two issues in MERRA are identified: 1)MERRAshows a spurious negative trend in Nebraska andKansas, which ismost likely related to the changes in the satellite observing system over time that has apparently affected the water cycle in the central United States, and 2) the patterns of positive trend over theGulf Coast states and along the East Coast seem to be correlated with the tropical cyclones in these regions. The analysis of the trends in the seasonal precipitation extremes indicates that the

  6. Evaluation of NASA’s MERRA Precipitation Product in Reproducing the Observed Trend and Distribution of Extreme Precipitation Events in the United States

    DOE PAGES

    Ashouri, Hamed; Sorooshian, Soroosh; Hsu, Kuo-Lin; ...

    2016-02-03

    This study evaluates the performance of NASA's Modern-Era Retrospective Analysis for Research and Applications (MERRA) precipitation product in reproducing the trend and distribution of extreme precipitation events. Utilizing the extreme value theory, time-invariant and time-variant extreme value distributions are developed to model the trends and changes in the patterns of extreme precipitation events over the contiguous United States during 1979-2010. The Climate Prediction Center (CPC)U.S.Unified gridded observation data are used as the observational dataset. The CPC analysis shows that the eastern and western parts of the United States are experiencing positive and negative trends in annual maxima, respectively. The continental-scalemore » patterns of change found in MERRA seem to reasonably mirror the observed patterns of change found in CPC. This is not previously expected, given the difficulty in constraining precipitation in reanalysis products. MERRA tends to overestimate the frequency at which the 99th percentile of precipitation is exceeded because this threshold tends to be lower in MERRA, making it easier to be exceeded. This feature is dominant during the summer months. MERRAtends to reproduce spatial patterns of the scale and location parameters of the generalized extreme value and generalized Pareto distributions. However, MERRA underestimates these parameters, particularly over the Gulf Coast states, leading to lower magnitudes in extreme precipitation events. Two issues in MERRA are identified: 1)MERRAshows a spurious negative trend in Nebraska andKansas, which ismost likely related to the changes in the satellite observing system over time that has apparently affected the water cycle in the central United States, and 2) the patterns of positive trend over theGulf Coast states and along the East Coast seem to be correlated with the tropical cyclones in these regions. The analysis of the trends in the seasonal precipitation extremes indicates

  7. Comparison and evaluation of satellite- and reanalysis-based precipitation products for water resources management in the Brahmaputra River basin

    NASA Astrophysics Data System (ADS)

    Saleh Khan, Abu; Sohel Masud, Md.; Abdulla Hel Kafi, Md.; Sultana, Tashrifa; Lopez Lopez, Patricia

    2017-04-01

    The Brahmaputra River, with a transboundary basin area of approx. 554,500 km2, has its origin on the northern slope of the Himalayas in China, from where it flows through India, Bhutan and finally Bangladesh. Brahmaputra basin's climatology is heavily conditioned by precipitation during the monsoon months, concentrating about the 85 % of the rainfall in this period and originating severe and frequent floods that impact specially the Bangladeshi population in the delta region. Recent campaigns to increase the quality and to share ground-based hydro-meteorological data, in particular precipitation, within the basin have provided limited results. Global rainfall data from satellite and reanalysis may improve the temporal and spatial availability of in-situ observations for advanced water resources management. This study aims to evaluate the applicability of several global precipitation products from satellite and reanalysis in comparison with in-situ data to quantify their added value for hydrological modeling at a basin and sub-basin scale for the Brahmaputra River. Precipitation products from CMORPH, TRMM-3B42, GsMAP, WFDEI, MSWEP and various combinations with ground-based data were evaluated at basin and sub-basin level at a daily and monthly temporal resolution. The Brahmaputra was delineated into 54 sub-basins for a more detailed evaluation of the precipitation products. The data were analysed and inter-compared for the time period from 2002 to 2010. Precipitation performance assessment was conducted including several indicators, such as probability of detection (POD), false alarm ratio (FAR), Pearson's correlation coefficient (r), bias and root mean square error (RMSE). Preliminary results indicate high correlation and low bias and RMSE values between WFDEI, TRMM-3B42 and CMORPH precipitation and in-situ observations at a monthly time scale. Lower correlations and higher bias and RMSE values were found between GsMAP and MSWEP and ground-observed precipitation

  8. Nitrogen decreases and precipitation increases ectomycorrhizal extramatrical mycelia production in a longleaf pine forest.

    PubMed

    Sims, Stephanie E; Hendricks, Joseph J; Mitchell, Robert J; Kuehn, Kevin A; Pecot, Stephen D

    2007-06-01

    The rates and controls of ectomycorrhizal fungal production were assessed in a 22-year-old longleaf pine (Pinus palustris Mill.) plantation using a complete factorial design that included two foliar scorching (control and 95% plus needle scorch) and two nitrogen (N) fertilization (control and 5 g N m(-2) year(-1)) treatments during an annual assessment. Ectomycorrhizal fungi production comprised of extramatrical mycelia, Hartig nets and mantles on fine root tips, and sporocarps was estimated to be 49 g m(-2) year(-1) in the control treatment plots. Extramatrical mycelia accounted for approximately 95% of the total mycorrhizal production estimate. Mycorrhizal production rates did not vary significantly among sample periods throughout the annual assessment (p = 0.1366). In addition, reduction in foliar leaf area via experimental scorching treatments did not influence mycorrhizal production (p = 0.9374), suggesting that stored carbon (C) may decouple the linkage between current photosynthate production and ectomycorrhizal fungi dynamics in this forest type. Nitrogen fertilization had a negative effect, whereas precipitation had a positive effect on mycorrhizal fungi production (p = 0.0292; r (2) = 0.42). These results support the widely speculated but poorly documented supposition that mycorrhizal fungi are a large and dynamic component of C flow and nutrient cycling dynamics in forest ecosystems.

  9. Evaluation of eight high spatial resolution gridded precipitation products in Adige Basin (Italy) at multiple temporal and spatial scales.

    PubMed

    Duan, Zheng; Liu, Junzhi; Tuo, Ye; Chiogna, Gabriele; Disse, Markus

    2016-12-15

    This study provides a comprehensive evaluation of eight high spatial resolution gridded precipitation products in Adige Basin located in Italy within 45-47.1°N. The Adige Basin is characterized by a complex topography, and independent ground data are available from a network of 101 rain gauges during 2000-2010. The eight products include the Version 7 TRMM (Tropical Rainfall Measuring Mission) Multi-satellite Precipitation Analysis 3B42 product, three products from CMORPH (the Climate Prediction Center MORPHing technique), i.e., CMORPH_RAW, CMORPH_CRT and CMORPH_BLD, PCDR (Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Climate Data Record), PGF (Global Meteorological Forcing Dataset for land surface modelling developed by Princeton University), CHIRPS (Climate Hazards Group InfraRed Precipitation with Station data) and GSMaP_MVK (Global Satellite Mapping of Precipitation project Moving Vector with Kalman-filter product). All eight products are evaluated against interpolated rain gauge data at the common 0.25° spatial resolution, and additional evaluations at native finer spatial resolution are conducted for CHIRPS (0.05°) and GSMaP_MVK (0.10°). Evaluation is performed at multiple temporal (daily, monthly and annual) and spatial scales (grid and watershed). Evaluation results show that in terms of overall statistical metrics the CHIRPS, TRMM and CMORPH_BLD comparably rank as the top three best performing products, while the PGF performs worst. All eight products underestimate and overestimate the occurrence frequency of daily precipitation for some intensity ranges. All products tend to show higher error in the winter months (December-February) when precipitation is low. Very slight difference can be observed in the evaluation metrics and aspects between at the aggregated 0.25° spatial resolution and at the native finer resolutions (0.05°) for CHIRPS and (0.10°) for GSMaP_MVK products. This study has implications

  10. Comparison and correction of three satellite precipitation estimates products to improve flood prevention in French Guiana

    NASA Astrophysics Data System (ADS)

    Beaufort, Aurélien; Gibier, Florian; Palany, Philippe

    2017-04-01

    The French Guiana (80 000 km2) is highly vulnerable to flooding during the rainy season but the hydrological prevision is limited. In fact, the region cannot be cover by a dense network of rain gauges because of the difficulties to install and maintain monitoring stations in the primary forest. In that case, meteorological satellites could be really useful. Their large spatial cover offers the opportunity to estimate rainfall at a regional scale, with a temporal resolution of 30 minutes. The use of daily satellite precipitation estimates products in hydrological modelling are not very developed but could lead to reduce spatiotemporal uncertainties of rainfall and improve simulations of hydrological models. In this study, we have tested three satellite-based rainfall estimation algorithms: TRMM-TMPA 3B42 (Tropical Rainfall Measuring Mission Multi-Satellite Precipitation analysis) V7 (spatial resolution: 0.25°), IMERG (Integrated Multi-satellitE Retrievals) for GPM (Global Precipitation Measurement) (spatial resolution: 0.1°) and STAR Satellite rainfall estimates Hydro-Estimator (spatial resolution: 0.045°). Then, we applied several methods for biases correction in order to improve daily rainfall estimates in comparison with measures from available rain gauges. The performance was evaluated at a daily time scale for the period running from 01/04/2015 to 30/03/2016 with validation data from 32 rain gauges managed by Meteo France and 59 rain gauges managed by the Surinam. Before biases correction, GPM IMERG obtained the better percentage of detection (POD) with 70% and a false alarm ratio (FAR) of only 10% in comparison with TRMM performance (POD: 60% ; FAR: 30%) and Hydro-Estimator (POD: 30% ; FAR: 30%). Biases (Psat-Pgau) were negatives with the three satellite products which mean that rainfall estimates by satellite images were underestimated. Better daily performances were obtained with TRMM (mean absolute biases: 7.1 mm; RMSE = 13.4 mm) and GPM (mean absolute

  11. Validation of the H-SAF precipitation product H03 over Greece using rain gauge data

    NASA Astrophysics Data System (ADS)

    Feidas, H.; Porcu, F.; Puca, S.; Rinollo, A.; Lagouvardos, C.; Kotroni, V.

    2016-11-01

    This paper presents an extensive validation of the combined infrared/microwave H-SAF (EUMETSAT Satellite Application Facility on Support to Operational Hydrology and Water Management) precipitation product H03, for a 1-year period, using gauge observations from a relatively dense network of 233 stations over Greece. First, the quality of the interpolated data used to validate the precipitation product is assessed and a quality index is constructed based on parameters such as the density of the station network and the orography. Then, a validation analysis is conducted based on comparisons of satellite (H03) with interpolated rain gauge data to produce continuous and multi-categorical statistics at monthly and annual timescales by taking into account the different geophysical characteristics of the terrain (land, coast, sea, elevation). Finally, the impact of the quality of interpolated data on the validation statistics is examined in terms of different configurations of the interpolation model and the rain gauge network characteristics used in the interpolation. The possibility of using a quality index of the interpolated data as a filter in the validation procedure is also investigated. The continuous validation statistics show yearly root mean squared error (RMSE) and mean absolute error (MAE) corresponding to the 225 and 105 % of the mean rain rate, respectively. Mean error (ME) indicates a slight overall tendency for underestimation of the rain gauge rates, which takes large values for the high rain rates. In general, the H03 algorithm cannot retrieve very well the light (< 1 mm/h) and the convective type (>10 mm/h) precipitation. The poor correlation between satellite and gauge data points to algorithm problems in co-locating precipitation patterns. Seasonal comparison shows that retrieval errors are lower for cold months than in the summer months of the year. The multi-categorical statistics indicate that the H03 algorithm is able to discriminate efficiently

  12. Assessment of Satellite-based Precipitation Products (TRMM) in Hydrologic Modeling: Case Studies from Northern Morocco

    NASA Astrophysics Data System (ADS)

    EL kadiri, R.; Milewski, A.; Durham, M.

    2012-12-01

    Precipitation is the most important forcing parameter in hydrological modeling, yet it is largely unknown in the arid Middle East. We assessed the magnitude, probability of detection, and false alarm rates of various rainfall satellite products (e.g., TRMM, RFE2.0) compared to in situ gauge data (~79 stations) across the Our Er Rbia, Sebou, and Melouya Watersheds in Northern Morocco. Precipitation over the area is relatively high with an average of ~400mm/year according to TRMM (1998-2008). The existing gauges indicate that the average annual precipitation across the Tadla and Coastal Plains region is 260mm/year and 390mm/year across the Atlas Mountains. Following the assessment of satellite products against in situ gauge data, we evaluated the effects (e.g., runoff and recharge amounts) of using satellite driven hydrologic models using SWAT. Specifically, we performed a four-fold exercise: (1) The first stage focused on the analysis of the rainfall products; (2) the second stage involved the construction of a rainfall-runoff model using gauge data; (3) the third stage entailed the calibration of the model against flow gauges and/or dams storage variability, and (4) model simulation using satellite based rainfall products using the calibrated parameters from the initial simulation. Results suggest the TRMM V7 has a much better correlation with the field data over the Oum Er Rbia watershed. The Correlation E (Nash-Suncliffe coefficient) has a positive value of 0.5, while the correlation coefficient of TRMM V6 vs. gauges data is a negative value of -0.25. This first order evaluation of the TRMM V7 shows the new algorithm has partially overcame the underestimation effect in the semi-arid environments. However, more research needs to be done to increase the usability of TRMM V7 in hydrologic models. Low correlations are most likely a result of the following: (1) snow at the high elevations in the Oum Er Rbia watershed, (2) the ocean effect on TRMM measurements along

  13. Dominant plant taxa predict plant productivity responses to CO2 enrichment across precipitation and soil gradients

    DOE PAGES

    Fay, Philip A.; Newingham, Beth A.; Polley, H. Wayne; ...

    2015-03-30

    The Earth’s atmosphere will continue to be enriched with carbon dioxide (CO2) over the coming century. Carbon dioxide enrichment often reduces leaf transpiration, which in water-limited ecosystems may increase soil water content, change species abundances and increase the productivity of plant communities. The effect of increased soil water on community productivity and community change may be greater in ecosystems with lower precipitation, or on coarser-textured soils, but responses are likely absent in deserts. We tested correlations among yearly increases in soil water content, community change and community plant productivity responses to CO2 enrichment in experiments in a mesic grassland withmore » fine- to coarse-textured soils, a semi-arid grassland and a xeric shrubland. We found no correlation between CO2-caused changes in soil water content and changes in biomass of dominant plant taxa or total community aboveground biomass in either grassland type or on any soil in the mesic grassland (P > 0.60). Instead, increases in dominant taxa biomass explained up to 85% of the increases in total community biomass under CO2 enrichment. The effect of community change on community productivity was stronger in the semi-arid grassland than in the mesic grassland,where community biomass change on one soil was not correlated with the change in either the soil water content or the dominant taxa. No sustained increases in soil water content or community productivity and no change in dominant plant taxa occurred in the xeric shrubland. Thus, community change was a crucial driver of community productivity responses to CO2 enrichment in the grasslands, but effects of soil water change on productivity were not evident in yearly responses to CO2 enrichment. In conclusion, future research is necessary to isolate and clarify the mechanisms controlling the temporal and spatial variations in the linkages among soil water, community change and plant productivity responses to CO2

  14. Dominant plant taxa predict plant productivity responses to CO2 enrichment across precipitation and soil gradients

    PubMed Central

    Fay, Philip A.; Newingham, Beth A.; Polley, H. Wayne; Morgan, Jack A.; LeCain, Daniel R.; Nowak, Robert S.; Smith, Stanley D.

    2015-01-01

    The Earth's atmosphere will continue to be enriched with carbon dioxide (CO2) over the coming century. Carbon dioxide enrichment often reduces leaf transpiration, which in water-limited ecosystems may increase soil water content, change species abundances and increase the productivity of plant communities. The effect of increased soil water on community productivity and community change may be greater in ecosystems with lower precipitation, or on coarser-textured soils, but responses are likely absent in deserts. We tested correlations among yearly increases in soil water content, community change and community plant productivity responses to CO2 enrichment in experiments in a mesic grassland with fine- to coarse-textured soils, a semi-arid grassland and a xeric shrubland. We found no correlation between CO2-caused changes in soil water content and changes in biomass of dominant plant taxa or total community aboveground biomass in either grassland type or on any soil in the mesic grassland (P > 0.60). Instead, increases in dominant taxa biomass explained up to 85 % of the increases in total community biomass under CO2 enrichment. The effect of community change on community productivity was stronger in the semi-arid grassland than in the mesic grassland, where community biomass change on one soil was not correlated with the change in either the soil water content or the dominant taxa. No sustained increases in soil water content or community productivity and no change in dominant plant taxa occurred in the xeric shrubland. Thus, community change was a crucial driver of community productivity responses to CO2 enrichment in the grasslands, but effects of soil water change on productivity were not evident in yearly responses to CO2 enrichment. Future research is necessary to isolate and clarify the mechanisms controlling the temporal and spatial variations in the linkages among soil water, community change and plant productivity responses to CO2 enrichment. PMID

  15. Performance of TMPA satellite precipitation product over the Northern Great Plains

    NASA Astrophysics Data System (ADS)

    Kharel, G.; Kirilenko, A.; Zhang, X.

    2011-12-01

    Satellite derived precipitation can be used as supplement and/or replacement to ground data in various applications including modeling and weather forecasting based on its accuracy, reliability and validity. We analyzed Tropical Rainfall Measuring Mission Multisatellite Precipitation Analysis (TMPA) 3B42 v.6 Level 3 product (0.25° × 0.25°, 3-hour resolution) against the United States Historical Climatology Network (USHCN) ground data from 98 stations in the Northern Great Plains (NGP) over the period of seven years (2003 to 2009). NGP, comprised of Wyoming, Montana, North Dakota, Minnesota, South Dakota and Nebraska states of the US, is located between the latitudes 41° - 49° N and longitudes 94° - 113.5° E within the TMPA product latitude band (50° NS).The goal of this research was to investigate the performance of TMPA over the NGP region. Results showed that the TMPA daily data has poor rainfall detection ability (POD ~ 0.3), weak correlation with the meteorological data (ρ=0.46) and high root mean square deviation (RMSD = 4.9 mm/day). We also found noticeable seasonal differences in the daily TMPA product performance. It underperformed during cold season (November to March) with weaker correlation (0.25) and worse POD (~ 0.15), as compared to relatively modest correlation (0.47) and POD (~0.30) during warm season (April to October). Our analysis at monthly scale revealed significantly better performance of TMPA with higher correlation (0.82) and lower RMSD (0.72 mm/day). Based on our findings, the TMPA daily data might be a poor replacement to ground data, however, at a monthly scale, TMPA can be used to estimate spatial rainfall distribution in NGP and/or as an input to a stochastic daily weather generator.

  16. Inhibition of the formation of oral calcium phosphate precipitates: the possible effects of certain honeybee products.

    PubMed

    Hidaka, S; Okamoto, Y; Ishiyama, K; Hashimoto, K

    2008-08-01

    We studied the effects of honeybee products on the in vitro formation of calcium phosphate precipitates. Screening tests of the in vitro formation of calcium phosphate precipitates using 20 types of honey and four types of propolis were carried out using the pH drop method. The inhibitory effect on the rate of amorphous calcium phosphate transformation to hydroxyapatite and on the induction time varied greatly among the 20 types of honey and four types of propolis. We classified them according to their effects on decreasing the rate of amorphous calcium phosphate transformation to hydroxyapatite and/or increasing the induction time. Two of the 20 honeys showed little or no inhibition, either on the rate of amorphous calcium phosphate transformation to hydroxyapatite or on the induction time. Six of the honeys reduced the rate of amorphous calcium phosphate transformation to hydroxyapatite by 12-35% and with a 2.5- to 4.4-fold increase in the induction time. The remaining 12 honeys showed even greater activity. Because four of these 12 honeys had an inhibitory effect on the rate of amorphous calcium phosphate formation, they were excluded as candidates for anticalculus agents. Furthermore, three of the four types of propolis showed an inhibitory effect that was the same as or greater than 1-hydroxyethylidene- 1,1-bisphosphonate. These results suggest that eight honeys and three types of propolis may have potential as anticalculus agents in toothpastes and mouthwashes.

  17. Global Precipitation Variations and Long-term Changes Derived from the GPCP Monthly Product

    NASA Technical Reports Server (NTRS)

    Adler, Robert F.; Gu, Guojun; Huffman, George; Curtis, Scott

    2005-01-01

    Global and large regional rainfall variations and possible long-term changes are examined using the 25-year (1979-2004) monthly dataset from the Global Precipitation Climatology Project (GPCP). The emphasis is to discriminate among the variations due to ENSO, volcanic events and possible long-term changes. Although the global change of precipitation in the data set is near zero, the data set does indicate an upward trend (0.13 mm/day/25yr) and a downward trend (-0.06 mm/day/25yr) over tropical oceans and lands (25S-25N), respectively. This corresponds to a 4% increase (ocean) and 2% decrease (land) during this time period. Techniques are applied to attempt to eliminate variations due to ENSO and major volcanic eruptions. The impact of the two major volcanic eruptions over the past 25 years is estimated to be about a 5% reduction in tropical rainfall. The modified data set (with ENSO and volcano effect removed) retains the same approximate change slopes, but with reduced variance leading to significance tests with results in the 90-95% range. Inter-comparisons between the GPCP, SSWI (1988-2004), and TRMM (1998-2004) rainfall products are made to increase or decrease confidence in the changes seen in the GPCP analysis.

  18. Variations of net ecosystem production due to seasonal precipitation differences in a tropical dry forest of northwest Mexico

    NASA Astrophysics Data System (ADS)

    Verduzco, Vivian S.; Garatuza-Payán, Jaime; Yépez, Enrico A.; Watts, Christopher J.; Rodríguez, Julio C.; Robles-Morua, Agustin; Vivoni, Enrique R.

    2015-10-01

    Due to their large extent and high primary productivity, tropical dry forests (TDF) are important contributors to atmospheric carbon exchanges in subtropical and tropical regions. In northwest Mexico, a bimodal precipitation regime that includes winter precipitation derived from Pacific storms and summer precipitation from the North American monsoon (NAM) couples water availability with ecosystem processes. We investigated the net ecosystem production of a TDF ecosystem using a 4.5 year record of water and carbon fluxes obtained from the eddy covariance method complemented with remotely sensed data. We identified a large CO2 efflux at the start of the summer season that is strongly related to the preceding winter precipitation and greenness. Since this CO2 efflux occurs prior to vegetation green-up, we infer that respiration is mainly due to decomposition of soil organic matter accumulated from the prior growing season. Overall, ecosystem respiration has an important effect on the net ecosystem production but can be overwhelmed by the strength of the primary productivity during the NAM. Precipitation characteristics during NAM have significant controls on sustaining carbon fixation in the TDF into the fall season. We identified that a threshold of ~350 to 400 mm of monsoon precipitation leads to a switch in the annual carbon balance in the TDF ecosystem from a net source (+102 g C/m2/yr) to a net sink (-249 g C/m2/yr). This monsoonal precipitation threshold is typically exceeded one out of every 2 years. The close coupling of winter and summer periods with respect to carbon fluxes suggests that the annual carbon balance is dependent on precipitation amounts in both seasons in TDF ecosystems.

  19. Changes in the TRMM Version-5 and Version-6 Precipitation Radar Products Due to Orbit Boost

    NASA Technical Reports Server (NTRS)

    Liao, Liang; Meneghini, Robert

    2010-01-01

    The performance of the version-5 and version-6 Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) products before and after the satellite orbit boost is assessed through a series of comparisons with Weather Surveillance Radar (WSR)-88D ground-based radar in Melbourne, Florida. Analysis of the comparisons of radar reflectivity near the storm top from the ground radar and both versions of the PR indicates that the PR bias relative to the WSR radar at Melbourne is on the order of 1dB for both pre- and post-boost periods, indicating that the PR products maintain accurate calibration after the orbit boost. Comparisons with the WSR-88D near-surface reflectivity factors indicate that both versions of the PR products accurately correct for attenuation in stratiform rain. However, in convective rain, both versions exhibit negative biases in the near-surface radar reflectivity with version-6 products having larger negative biases than version-5. Rain rate comparisons between the ground and space radars show similar characteristics

  20. A suite of global reconstructed precipitation products and their error estimate by multivariate regression using empirical orthogonal functions: 1850-present

    NASA Astrophysics Data System (ADS)

    Shen, S. S.

    2014-12-01

    This presentation describes a suite of global precipitation products reconstructed by a multivariate regression method using an empirical orthogonal function (EOF) expansion. The sampling errors of the reconstruction are estimated for each product datum entry. The maximum temporal coverage is 1850-present and the spatial coverage is quasi-global (75S, 75N). The temporal resolution ranges from 5-day, monthly, to seasonal and annual. The Global Precipitation Climatology Project (GPCP) precipitation data from 1979-2008 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 in detail for different EOF modes. 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 examples of 1983 El Niño precipitation and 1917 La Niña precipitation (Figure 1) demonstrate that the El Niño and La Niña precipitation patterns are well reflected in the first two EOFs. The validation of our reconstruction results with GPCP makes it possible to use the reconstruction as the benchmark data for climate models. This will help the climate modeling community to improve model precipitation mechanisms and reduce the systematic difference between observed global precipitation, which hovers at around 2.7 mm/day for reconstructions and GPCP, and model precipitations, which have a range of 2.6-3.3 mm/day for CMIP5. 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 between San Diego State University (Sam Shen, Nancy Tafolla, Barbara Sperberg, and Melanie Thorn) and University of Maryland (Phil

  1. Comparison of precipitable water over Ghana using GPS signals and reanalysis products

    NASA Astrophysics Data System (ADS)

    Acheampong, A. A.; Fosu, C.; Amekudzi, L. K.; Kaas, E.

    2015-11-01

    Signals from Global Navigational Satellite Systems (GNSS) when integrated with surface meteorological parameters can be used to sense atmospheric water vapour. Using gLAB software and employing precise point positioning techniques, zenith troposphere delays (ZTD) for a GPS base station at KNUST, Kumasi have been computed and used to retrieve Precipitable Water (PW). The PW values obtained were compared with products from ERA-Interim and NCEP reanalysis data. The correlation coefficients, r, determined from these comparisons were 0.839 and 0.729 for ERA-interim and NCEP respectively. This study has demonstrated that water vapour can be retrieved with high precision from GNSS signal. Furthermore, a location map have been produced to serve as a guide in adopting and installing GNSS base stations in Ghana to achieve a country wide coverage of GNSS based water vapour monitoring.

  2. Reconciling inconsistencies in precipitation-productivity relationships: implications for climate change.

    PubMed

    Knapp, Alan K; Ciais, Philippe; Smith, Melinda D

    2017-04-01

    Contents 41 I. 41 II. 42 III. 43 IV. 44 V. 45 Acknowledgements 46 References 46 SUMMARY: Precipitation (PPT) is a primary climatic determinant of plant growth and aboveground net primary production (ANPP) over much of the globe. Thus, PPT-ANPP relationships are important both ecologically and to land-atmosphere models that couple terrestrial vegetation to the global carbon cycle. Empirical PPT-ANPP relationships derived from long-term site-based data are almost always portrayed as linear, but recent evidence has accumulated that is inconsistent with an underlying linear relationship. We review, and then reconcile, these inconsistencies with a nonlinear model that incorporates observed asymmetries in PPT-ANPP relationships. Although data are currently lacking for parameterization, this new model highlights research needs that, when met, will improve our understanding of carbon cycle dynamics, as well as forecasts of ecosystem responses to climate change.

  3. Inter-Sensor Comparison of Microwave Land Surface Emissivity Products to Improve Precipitation Retrievals

    NASA Astrophysics Data System (ADS)

    Norouzi, H.; Temimi, M.; Turk, J.; Prigent, C.; Furuzawa, F.; Tian, Y.

    2013-12-01

    Microwave land surface emissivity acts as the background signal to estimate rain rate, cloud liquid water, and total precipitable water. Therefore, its accuracy can directly affect the uncertainty of such measurements. Over land, unlike over oceans, the microwave emissivity is relatively high and and varies significantly as surface conditions and land cover change. Lack of ground truth measurement of microwave emissivity especially on global scale has made the uncertainty analysis of this parameter very challenging. The present study investigates the consistency among the existing global land emissivity estimates from different microwave sensors. The products are determined from various sensors and frequencies ranging from 7 to 90 GHz. The selected emissivity products in this study are from the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) by NOAA - Cooperative remote Sensing and Science and Technology Center (CREST), the Special Sensor Microwave Imager (SSM/I) by The Centre National de la Recherche Scientifique (CNRS) in France, TRMM Microwave Imager (TMI) by Nagoya University, Japan, and WindSat by NASA Jet Propulsion Laboratory (JPL). The emissivity estimates are based on different algorithms and ancillary data sets. This work investigates the difference among these emissivity products from 2003 to 2008 dynamically and spectrally. The similarities and discrepancies of the retrievals are studied at different land cover types. The mean relative difference (MRD) and other statistical parameters are calculated temporally for all five years of the study. Some inherent discrepancies between the selected products can be attributed to the difference in geometry in terms of incident angle, spectral response, and the foot print size which can affect the estimations. The results reveal that in lower frequencies (=<19 GHz) ancillary data especially skin temperature data set is the major source of difference in emissivity retrievals, while in higher frequencies

  4. Incorporating TRMM and Other High-Quality Estimates into the One-Degree Daily (1DD) Global Precipitation Product

    NASA Technical Reports Server (NTRS)

    Huffman, George J.; Adler, Robert F.; Bolvin, David T.

    1999-01-01

    The One-Degree Daily (1DD) precipitation dataset was recently developed for the Global Precipitation Climatology Project (GPCP). The IDD provides a globally-complete, observation-only estimate of precipitation on a daily 1 deg x 1 deg grid for the period 1997 through late 1999 (by the time of the conference). In the latitude band 40 N - 40 S the IDD uses the Threshold-Matched Precipitation Index (TMPI), a GPI-like IR product with the T(sub b) threshold and (single) conditional rain rate determined locally for each month by the frequency of precipitation in the GPROF SSNU product and by the precipitation amount in the GPCP satellite-gauge (SG) combination. Outside 40 N - 40 S the 1DD uses a scaled TOVS precipitation estimate that has adjustments based on the TMPI and the SG. This first-generation 1DD has been in beta test preparatory to release as an official GPCP product. In this paper we discuss further development of the 1DD framework to allow the direct incorporation of TRMM and other high-quality precipitation estimates. First, these data are generally sparse (typically from low-orbit satellites), so a fair amount of work was devoted to data boundaries. Second, these data are not the same as the original 1DD estimates, so we had to give careful consideration to the best scheme for forcing the 1DD to sum to the SG for the month. Finally, the non-sun-synchronous, low-inclination orbit occupied by TRMM creates interesting variations against the sun-synchronous, high-inclination orbits occupied by the Defense Meteorological Satellite Program satellites that carry the SSM/I. Examples will be given of each of the development issues, then comparisons will be made to daily raingauge analyses.

  5. Incorporating TRMM and Other High-Quality Estimates into the One-Degree Daily (1DD) Global Precipitation Product

    NASA Technical Reports Server (NTRS)

    Huffman, George J.; Adler, Robert F.; Bolvin, David T.

    1999-01-01

    The One-Degree Daily (1DD) precipitation dataset was recently developed for the Global Precipitation Climatology Project (GPCP). The IDD provides a globally-complete, observation-only estimate of precipitation on a daily 1 deg x 1 deg grid for the period 1997 through late 1999 (by the time of the conference). In the latitude band 40 N - 40 S the IDD uses the Threshold-Matched Precipitation Index (TMPI), a GPI-like IR product with the T(sub b) threshold and (single) conditional rain rate determined locally for each month by the frequency of precipitation in the GPROF SSNU product and by the precipitation amount in the GPCP satellite-gauge (SG) combination. Outside 40 N - 40 S the 1DD uses a scaled TOVS precipitation estimate that has adjustments based on the TMPI and the SG. This first-generation 1DD has been in beta test preparatory to release as an official GPCP product. In this paper we discuss further development of the 1DD framework to allow the direct incorporation of TRMM and other high-quality precipitation estimates. First, these data are generally sparse (typically from low-orbit satellites), so a fair amount of work was devoted to data boundaries. Second, these data are not the same as the original 1DD estimates, so we had to give careful consideration to the best scheme for forcing the 1DD to sum to the SG for the month. Finally, the non-sun-synchronous, low-inclination orbit occupied by TRMM creates interesting variations against the sun-synchronous, high-inclination orbits occupied by the Defense Meteorological Satellite Program satellites that carry the SSM/I. Examples will be given of each of the development issues, then comparisons will be made to daily raingauge analyses.

  6. Comparing regional precipitation and temperature extremes in climate model and reanalysis products.

    PubMed

    Angélil, Oliver; Perkins-Kirkpatrick, Sarah; Alexander, Lisa V; Stone, Dáithí; Donat, Markus G; Wehner, Michael; Shiogama, Hideo; Ciavarella, Andrew; Christidis, Nikolaos

    2016-09-01

    A growing field of research aims to characterise the contribution of anthropogenic emissions to the likelihood of extreme weather and climate events. These analyses can be sensitive to the shapes of the tails of simulated distributions. If tails are found to be unrealistically short or long, the anthropogenic signal emerges more or less clearly, respectively, from the noise of possible weather. Here we compare the chance of daily land-surface precipitation and near-surface temperature extremes generated by three Atmospheric Global Climate Models typically used for event attribution, with distributions from six reanalysis products. The likelihoods of extremes are compared for area-averages over grid cell and regional sized spatial domains. Results suggest a bias favouring overly strong attribution estimates for hot and cold events over many regions of Africa and Australia, and a bias favouring overly weak attribution estimates over regions of North America and Asia. For rainfall, results are more sensitive to geographic location. Although the three models show similar results over many regions, they do disagree over others. Equally, results highlight the discrepancy amongst reanalyses products. This emphasises the importance of using multiple reanalysis and/or observation products, as well as multiple models in event attribution studies.

  7. Exogenous N addition enhances the responses of gross primary productivity to individual precipitation events in a temperate grassland

    PubMed Central

    Guo, Qun; Hu, Zhong-min; Li, Sheng-gong; Yu, Gui-rui; Sun, Xiao-min; Li, Ling-hao; Liang, Nai-shen; Bai, Wen-ming

    2016-01-01

    Predicted future shifts in the magnitude and frequency (larger but fewer) of precipitation events and enhanced nitrogen (N) deposition may interact to affect grassland productivity, but the effects of N enrichment on the productivity response to individual precipitation events remain unclear. In this study, we quantified the effects of N addition on the response patterns of gross primary productivity (GPP) to individual precipitation events of different sizes (Psize) in a temperate grassland in China. The results showed that N enrichment significantly increased the time-integrated amount of GPP in response to an individual precipitation event (GPPtotal), and the N-induced stimulation of GPP increased with increasing Psize. N enrichment rarely affected the duration of the GPP response, but it significantly stimulated the maximum absolute GPP response. Higher foliar N content might play an important role in the N-induced stimulation of GPP. GPPtotal in both the N-addition and control treatments increased linearly with Psize with similar Psize intercepts (approximately 5 mm, indicating a similar lower Psize threshold to stimulate the GPP response) but had a steeper slope under N addition. Our work indicates that the projected larger precipitation events will stimulate grassland productivity, and this stimulation might be amplified by increasing N deposition. PMID:27264386

  8. Statistical evaluation of the performance of gridded monthly precipitation products from reanalysis data, satellite estimates, and merged analyses over China

    NASA Astrophysics Data System (ADS)

    Deng, Xueliang; Nie, Suping; Deng, Weitao; Cao, Weihua

    2017-04-01

    In this study, we compared the following four different gridded monthly precipitation products: the National Centers for Environmental Prediction version 2 (NCEP-2) reanalysis data, the satellite-based Climate Prediction Center Morphing technique (CMORPH) data, the merged satellite-gauge Global Precipitation Climatology Project (GPCP) data, and the merged satellite-gauge-model data from the Beijing Climate Center Merged Estimation of Precipitation (BMEP). We evaluated the performances of these products using monthly precipitation observations spanning the period of January 2003 to December 2013 from a dense, national, rain gauge network in China. Our assessment involved several statistical techniques, including spatial pattern, temporal variation, bias, root-mean-square error (RMSE), and correlation coefficient (CC) analysis. The results show that NCEP-2, GPCP, and BMEP generally overestimate monthly precipitation at the national scale and CMORPH underestimates it. However, all of the datasets successfully characterized the northwest to southeast increase in the monthly precipitation over China. Because they include precipitation gauge information from the Global Telecommunication System (GTS) network, GPCP and BMEP have much smaller biases, lower RMSEs, and higher CCs than NCEP-2 and CMORPH. When the seasonal and regional variations are considered, NCEP-2 has a larger error over southern China during the summer. CMORPH poorly reproduces the magnitude of the precipitation over southeastern China and the temporal correlation over western and northwestern China during all seasons. BMEP has a lower RMSE and higher CC than GPCP over eastern and southern China, where the station network is dense. In contrast, BMEP has a lower CC than GPCP over western and northwestern China, where the gauge network is relatively sparse.

  9. Comparison of precipitation estimates between Version 7 3-hourly TRMM Multi-Satellite Precipitation Analysis (TMPA) near-real-time and research products

    NASA Astrophysics Data System (ADS)

    Liu, Zhong

    2015-02-01

    Over the years, blended methods that use multi-satellites and multi-sensors have been developed for estimating global precipitation and resulting products are widely used in applications. An example is the 3-hourly TRMM (Tropical Rainfall Measuring Mission) Multi-Satellite Precipitation Analysis (TMPA) that consists of two products: near-real-time (3B42RT) and research-grade (3B42). The former provides quick, less accurate estimates suitable for monitoring activities; the latter provides more accurate estimates more suitable for research. Both products have been widely used in research and applications. Nonetheless, to improve near-real-time applications, it is important to understand their difference. In this study, seasonal mean difference (MD), mean absolute difference (MAD), root mean square difference (RMSD), and their inter-annual variations in boreal (June, July and August or JJA) and austral (December, January and February or DJF) summers and in different rain regimes over two surface types are investigated on a large scale (50°N-50°S) from 2000 and 2012. Over land, positive MD values (3B42RT > 3B42) dominate, especially in western China, western United States, northwest Asia and over some oceanic regions of light rain in both JJA and DJF. Over ocean, negative MD values (3B42RT < 3B42) prevail, except over regions of light rain. In general, relative (to 3B42) MD values increase with rain rate. Variation of the individual differences between the two products is small (large) over regions of heavy (light) rain. There is no significant inter-annual variation in the seasonal mean statistics. The difference between the two products is likely due to the algorithms and further investigations are needed.

  10. Effects of precipitation and temperature on crop production variability in northeast Iran.

    PubMed

    Bannayan, Mohammad; Lotfabadi, Sajad Sadeghi; Sanjani, Sarah; Mohamadian, Azadeh; Aghaalikhani, Majid

    2011-05-01

    Climate variability adversely impacts crop production and imposes a major constraint on farming planning, mostly under rainfed conditions, across the world. Considering the recent advances in climate science, many studies are trying to provide a reliable basis for climate, and subsequently agricultural production, forecasts. The El Niño-Southern Oscillation phenomenon (ENSO) is one of the principle sources of interannual climatic variability. In Iran, primarily in the northeast, rainfed cereal yield shows a high annual variability. This study investigated the role played by precipitation, temperature and three climate indices [Arctic Oscillation (AO), North Atlantic Oscillation (NAO) and NINO 3.4] in historically observed rainfed crop yields (1983-2005) of both barley and wheat in the northeast of Iran. The results revealed differences in the association between crop yield and climatic factors at different locations. The south of the study area is a very hot location, and the maximum temperature proved to be the limiting and determining factor for crop yields; temperature variability resulted in crop yield variability. For the north of the study area, NINO 3.4 exhibited a clear association trend with crop yields. In central locations, NAO provided a solid basis for the relationship between crop yields and climate factors.

  11. TRMM Common Microphysics Products: A Tool for Evaluating Spaceborne Precipitation Retrieval Algorithms

    NASA Technical Reports Server (NTRS)

    Kingsmill, David E.; Yuter, Sandra E.; Hobbs, Peter V.; Rangno, Arthur L.; Heymsfield, Andrew J.; Stith, Jeffrey L.; Bansemer, Aaron; Haggerty, Julie A.; Korolev, Alexei V.

    2004-01-01

    A customized product for analysis of microphysics data collected from aircraft during field campaigns in support of the TRMM program is described. These Common Microphysics Products (CMP's) are designed to aid in evaluation of TRMM spaceborne precipitation retrieval algorithms. Information needed for this purpose (e.g., particle size spectra and habit, liquid and ice water content) was derived using a common processing strategy on the wide variety of microphysical instruments and raw native data formats employed in the field campaigns. The CMP's are organized into an ASCII structure to allow easy access to the data for those less familiar with and without the tools to accomplish microphysical data processing. Detailed examples of the CMP show its potential and some of its limitations. This approach may be a first step toward developing a generalized microphysics format and an associated community-oriented, non-proprietary software package for microphysics data processing, initiatives that would likely broaden community access to and use of microphysics datasets.

  12. Stochastic error model corrections to improve the performance of bottom-up precipitation products for hydrologic applications

    NASA Astrophysics Data System (ADS)

    Maggioni, V.; Massari, C.; Ciabatta, L.; Brocca, L.

    2016-12-01

    Accurate quantitative precipitation estimation is of great importance for water resources management, agricultural planning, and forecasting and monitoring of natural hazards such as flash floods and landslides. In situ observations are limited around the Earth, especially in remote areas (e.g., complex terrain, dense vegetation), but currently available satellite precipitation products are able to provide global precipitation estimates with an accuracy that depends upon many factors (e.g., type of storms, temporal sampling, season, etc.). The recent SM2RAIN approach proposes to estimate rainfall by using satellite soil moisture observations. As opposed to traditional satellite precipitation methods, which sense cloud properties to retrieve instantaneous estimates, this new bottom-up approach makes use of two consecutive soil moisture measurements for obtaining an estimate of the fallen precipitation within the interval between two satellite overpasses. As a result, the nature of the measurement is different and complementary to the one of classical precipitation products and could provide a different valid perspective to substitute or improve current rainfall estimates. However, uncertainties in the SM2RAIN product are still not well known and could represent a limitation in utilizing this dataset for hydrological applications. Therefore, quantifying the uncertainty associated with SM2RAIN is necessary for enabling its use. The study is conducted over the Italian territory for a 5-yr period (2010-2014). A number of satellite precipitation error properties, typically used in error modeling, are investigated and include probability of detection, false alarm rates, missed events, spatial correlation of the error, and hit biases. After this preliminary uncertainty analysis, the potential of applying the stochastic rainfall error model SREM2D to correct SM2RAIN and to improve its performance in hydrologic applications is investigated. The use of SREM2D for

  13. A description of the global land-surface precipitation data products of the Global Precipitation Climatology Centre with sample applications including centennial (trend) analysis from 1901-present

    NASA Astrophysics Data System (ADS)

    Becker, A.; Finger, P.; Meyer-Christoffer, A.; Rudolf, B.; Schamm, K.; Schneider, U.; Ziese, M.

    2013-02-01

    The availability of highly accessible and reliable monthly gridded data sets of global land-surface precipitation is a need that was already identified in the mid-1980s when there was a complete lack of globally homogeneous gauge-based precipitation analyses. Since 1989, the Global Precipitation Climatology Centre (GPCC) has built up its unique capacity to assemble, quality assure, and analyse rain gauge data gathered from all over the world. The resulting database has exceeded 200 yr in temporal coverage and has acquired data from more than 85 000 stations worldwide. Based on this database, this paper provides the reference publication for the four globally gridded monthly precipitation products of the GPCC, covering a 111-yr analysis period from 1901-present. As required for a reference publication, the content of the product portfolio, as well as the underlying methodologies to process and interpolate are detailed. Moreover, we provide information on the systematic and statistical errors associated with the data products. Finally, sample applications provide potential users of GPCC data products with suitable advice on capabilities and constraints of the gridded data sets. In doing so, the capabilities to access El Niño-Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO) sensitive precipitation regions and to perform trend analyses across the past 110 yr are demonstrated. The four gridded products, i.e. the Climatology (CLIM) V2011, the Full Data Reanalysis (FD) V6, the Monitoring Product (MP) V4, and the First Guess Product (FG), are publicly available on easily accessible latitude/longitude grids encoded in zipped clear text ASCII files for subsequent visualization and download through the GPCC download gate hosted on ftp://ftp.dwd.de/pub/data/gpcc/html/download_gate.html by the Deutscher Wetterdienst (DWD), Offenbach, Germany. Depending on the product, four (0

  14. A description of the global land-surface precipitation data products of the Global Precipitation Climatology Centre with sample applications including centennial (trend) analysis from 1901-present

    NASA Astrophysics Data System (ADS)

    Becker, A.; Finger, P.; Meyer-Christoffer, A.; Rudolf, B.; Schamm, K.; Schneider, U.; Ziese, M.

    2012-09-01

    The availability of highly accessible and reliable monthly gridded data sets of the global land-surface precipitation is a need that has already been identified in the mid-80s when there was a complete lack of a globally homogeneous gauge based precipitation analysis. Since 1989 the Global Precipitation Climatology Centre (GPCC) has built up a unique capacity to assemble, quality assure, and analyse rain gauge data gathered from all over the world. The resulting data base has exceeded 200 yr in temporal coverage and has acquired data from more than 85 000 stations world-wide. This paper provides the reference publication for the four globally gridded monthly precipitation products of the GPCC covering a 111-yr analysis period from 1901-present, processed from this data base. As required for a reference publication, the content of the product portfolio, as well as the underlying methodologies to process and interpolate are detailed. Moreover, we provide information on the systematic and statistical errors associated with the data products. Finally, sample applications provide potential users of GPCC data products with suitable advice on capabilities and constraints of the gridded data sets. In doing so, the capabilities to access ENSO and NAO sensitive precipitation regions and to perform trend analysis across the past 110 yr are demonstrated. The four gridded products, i.e. the Climatology V2011 (CLIM), the Full Data Reanalysis (FD) V6, the Monitoring Product (MP) V4, and the First Guess Product (FG) are public available on easy accessible latitude longitude grids encoded in zipped clear text ASCII files for subsequent visualization and download through the GPCC download gate hosted on ftp://ftp.dwd.de/pub/data/gpcc/html/download_gate.html by the Deutscher Wetterdienst (DWD), Offenbach, Germany. Depending on the product four (0.25°, 0.5°, 1.0°, 2.5° for CLIM), three (0.5°, 1.0

  15. Sensitivity of a Cumulus Parameterization Scheme to Precipitation Production Representation and Its Impact on a Heavy Rain Event over Korea

    SciTech Connect

    Han, Ji-Young; Hong, Song-You; Sunny Lim, Kyo-Sun; Han, Jongil

    2016-06-01

    The sensitivity of a cumulus parameterization scheme (CPS) to a representation of precipitation production is examined. To do this, the parameter that determines the fraction of cloud condensate converted to precipitation in the simplified Arakawa–Schubert (SAS) convection scheme is modified following the results from a cloud-resolving simulation. While the original conversion parameter is assumed to be constant, the revised parameter includes a temperature dependency above the freezing level, whichleadstolessproductionoffrozenprecipitating condensate with height. The revised CPS has been evaluated for a heavy rainfall event over Korea as well as medium-range forecasts using the Global/Regional Integrated Model system (GRIMs). The inefficient conversion of cloud condensate to convective precipitation at colder temperatures generally leads to a decrease in pre-cipitation, especially in the category of heavy rainfall. The resultant increase of detrained moisture induces moistening and cooling at the top of clouds. A statistical evaluation of the medium-range forecasts with the revised precipitation conversion parameter shows an overall improvement of the forecast skill in precipitation and large-scale fields, indicating importance of more realistic representation of microphysical processes in CPSs.

  16. Production of crystalline refractory metal oxides containing colloidal metal precipitates and useful as solar-effective absorbers

    DOEpatents

    Narayan, Jagdish; Chen, Yok

    1983-01-01

    This invention is a new process for producing refractory crystalline oxides having improved or unusual properties. The process comprises the steps of forming a doped-metal crystal of the oxide; exposing the doped crystal in a bomb to a reducing atmosphere at superatmospheric pressure and a temperature effecting precipitation of the dopant metal in the crystal lattice of the oxide but insufficient to effect net diffusion of the metal out of the lattice; and then cooling the crystal. Preferably, the cooling step is effected by quenching. The process forms colloidal precipitates of the metal in the oxide lattice. The process may be used, for example, to produce thermally stable black MgO crystalline bodies containing magnetic colloidal precipitates consisting of about 99% Ni. The Ni-containing bodies are solar-selective absorbers, having a room-temperature absorptivity of about 0.96 over virtually all of the solar-energy spectrum and exhibiting an absorption edge in the region of 2 .mu.m. The process parameters can be varied to control the average size of the precipitates. The process can produce a black MgO crystalline body containing colloidal Ni precipitates, some of which have the face-centered-cubic structure and others of which have the body-centered cubic structure. The products of the process are metal-precipitate-containing refractory crystalline oxides which have improved or unique optical, mechanical, magnetic, and/or electronic properties.

  17. Effects of increased nitrogen deposition and precipitation on seed and seedling production of Potentilla tanacetifolia in a temperate steppe ecosystem.

    PubMed

    Li, Yang; Yang, Haijun; Xia, Jianyang; Zhang, Wenhao; Wan, Shiqiang; Li, Linghao

    2011-01-01

    The responses of plant seeds and seedlings to changing atmospheric nitrogen (N) deposition and precipitation regimes determine plant population dynamics and community composition under global change. In a temperate steppe in northern China, seeds of P. tanacetifolia were collected from a field-based experiment with N addition and increased precipitation to measure changes in their traits (production, mass, germination). Seedlings germinated from those seeds were grown in a greenhouse to examine the effects of improved N and water availability in maternal and offspring environments on seedling growth. Maternal N-addition stimulated seed production, but it suppressed seed mass, germination rate and seedling biomass of P. tanacetifolia. Maternal N-addition also enhanced responses of seedlings to N and water addition in the offspring environment. Maternal increased-precipitation stimulated seed production, but it had no effect on seed mass and germination rate. Maternal increased-precipitation enhanced seedling growth when grown under similar conditions, whereas seedling responses to offspring N- and water-addition were suppressed by maternal increased-precipitation. Both offspring N-addition and increased-precipitation stimulated growth of seedlings germinated from seeds collected from the maternal control environment without either N or water addition. Our observations indicate that both maternal and offspring environments can influence seedling growth of P. tanacetifolia with consequent impacts on the future population dynamics of this species in the study area. The findings highlight the importance of the maternal effects on seed and seedling production as well as responses of offspring to changing environmental drivers in mechanistic understanding and projecting of plant population dynamics under global change.

  18. The Evolution of Remotely Sensed Precipitation Products for Hydrological Applications with a Focus on the Tropical Rainfall Measurement Mission (TRMM)

    NASA Astrophysics Data System (ADS)

    Tobin, K. J.; Bennett, M.

    2012-12-01

    This study examines the evolution of how remotely sensed precipitation products have impacted hydrologic modeling from six basins across the continental United States. Precipitation products include both ground-based (Multisensor Precipitation Estimator - MPE) and space-based products. Two space-based products are from the Tropical Rainfall Measurement Mission (TRMM) and include the real-time TRMM Multi-Satellite Precipitation Analysis (TMPA-RT) and TRMM 3B42 Research product. Precipitation products are compared between early (2004-2008) and late (2008-2010) periods. Additionally, version 6 and the new version 7 of these TRMM products are examined. Watersheds examined were moderately large (1000 to 1,000 square kilometers) and included the San Pedro (Arizona), Cimarron (Oklahoma); Alapaha (Georgia), mid-Nueces (Texas), San Casimiro (Texas), and the mid-Rio Grande basins, which is a bi-national basin that spans the Texas-Mexico border. Precipitation products are used to drive streamflow simulations using the Soil Water Assessment Tool (SWAT). The main results of this study concludes that MPE is a mature remote sensing product that generally supports superior hydrologic simulations based on standard performance metrics such as mass balance error, Nash-Sutcliffe efficiency coefficient, and coefficient of persistence. TRMM products support acceptable simulations and have improved in performance between early and late periods for TMPA-RT (both versions) and version 6 of TRMM 3B42 Research in five out of the six basins examined. This improvement is related to modification of TRMM in January 2009 with the addition of more satellite data and a climatologic bias correction, which greatly improves the real-time TMPA-RT product. Conversely, version 7 of the TRMM 3B42 Research has a positive bias compared to version 6, which is translated into poorer hydrological simulations of streamflow. Future research is urgently needed to determine if the issues observed in this study are

  19. Correcting satellite-based precipitation products from SMOS soil moisture data assimilation using two models of different complexity

    NASA Astrophysics Data System (ADS)

    Román-Cascón, Carlos; Pellarin, Thierry; Gibon, François

    2017-04-01

    Real-time precipitation information at the global scale is quite useful information for many applications. However, satellite-based precipitation products in real time are known to be biased from real values observed in situ. On the other hand, the information about precipitation contained in soil moisture data can be very useful to improve precipitation estimation, since the evolution of this variable is highly influenced by the amount of rainfall at a certain area after a rain event. In this context, the soil moisture data from the Soil Moisture Ocean Salinity (SMOS) satellite is used to correct the precipitation provided by real-time satellite-based products such as CMORPH, TRMM-3B42RT or PERSIANN. In this work, we test an assimilation algorithm based on the data assimilation of SMOS measurements in two models of different complexity: a simple hydrological model (Antecedent Precipitation Index (API)) and a state-of-the-art complex land-surface model (Surface Externalisée (SURFEX)). We show how the assimilation technique, based on a particle filter method, leads to the improvement of correlation and root mean squared error (RMSE) of precipitation estimates, with slightly better results for the simpler (and less expensive computationally) API model. This methodology has been evaluated for six years in ten sites around the world with different features, showing the limitations of the methodology in regions affected by mountainous terrain or by high radio-frequency interferences (RFI), which notably affect the quality of the soil moisture retrievals from brightness temperatures by SMOS. The presented results are promising for a potential near-real time application at the global scale.

  20. An independent assessment of the monthly PRISM gridded precipitation product in central Oklahoma

    USDA-ARS?s Scientific Manuscript database

    The development of climate-informed decision support tools for agricultural management requires long-duration location-specific climatologies due to the extreme spatiotemporal variability of precipitation. The traditional source of precipitation data (rain gauges) are too sparsely located to fill t...

  1. Convergence of Dynamic Vegetation Net Productivity Responses to Precipitation Variability from 10 Years of MODIS EVI

    USDA-ARS?s Scientific Manuscript database

    According to Global Climate Models (GCMs) the occurrence of extreme events of precipitation will be more frequent in the future. Therefore, important challenges arise regarding climate variability, which are mainly related to the understanding of ecosystem responses to changes in precipitation patte...

  2. MODIS EVI as a Surrogate for Net Primary Production across Precipitation Regimes

    USDA-ARS?s Scientific Manuscript database

    According to Global Climate Models (GCMs) the occurrence of extreme events of precipitation will be more frequent in the future. Therefore, important challenges arise regarding climate variability, which are mainly related to the understanding of ecosystem responses to changes in precipitation patte...

  3. Soil modulates the effect of precipitation seasonality on bioenergy crop production

    USDA-ARS?s Scientific Manuscript database

    Background/Questions/Methods Future climate change scenarios remain uncertain with respect to precipitation amounts and variability. In the U.S. Great Plains, spring precipitation is expected to decrease in the lower Great Plains but increase 20%–40% in the upper Mississippi Valley, suggesting pot...

  4. Dynamical downscaling improves upon gridded precipitation products in the Sierra Nevada, California

    NASA Astrophysics Data System (ADS)

    Hughes, Mimi; Lundquist, Jessica D.; Henn, Brian

    2017-04-01

    Uncertainties in gridded and regional climate estimates of precipitation are large at high elevations, where observations are sparse and spatial variability is substantial. We explore these uncertainties for water year 2008 across California's Sierra Nevada in 10 datasets: 6 regional climate downscalings generated using the weather research and forecasting (WRF) model at convection-permitting resolution with differing lateral boundary conditions and microphysical parameterizations, and four gauge-based, interpolation-gridded precipitation datasets. Precipitation from these 10 datasets is evaluated against 95 snow pillows and a precipitation dataset inferred from stream gauges using a Bayesian inference method. During water year 2008, the gridded datasets tend to underestimate frozen precipitation on the windward slope of the Sierra Nevada, particularly in the vicinity of Yosemite National Park. The WRF simulations with single-moment microphysics tend to overestimate precipitation throughout much of the region, whereas the WRF simulations with double-moment microphysics tend to better agree with both the snow pillows and inferred precipitation estimates, although they somewhat overestimate the windward/leeside precipitation contrast in the northern Sierra Nevada. WRF simulations, in particular those with single-moment microphysics, better distinguish spatial patterns of wet-versus-dry pillows and watersheds over the water year than the gridded estimates. Our results suggest treating gauge-based datasets as `truth' may give a misleading representation of model accuracy, since these gauge-based datasets often have issues of their own.

  5. Dynamical Downscaling Overcomes Deficiencies in Gridded Precipitation Products in the Sierra Nevada, California

    NASA Astrophysics Data System (ADS)

    Hughes, M.; Lundquist, J. D.; Henn, B. M.

    2016-12-01

    Uncertainties in gridded and regional climate estimates of precipitation are large at high elevations where observations are sparse and spatial variability is substantial. We explore these uncertainties for a climatologically-unusual water year across California's Sierra Nevada in 10 datasets: six Weather, Research, and Forecasting (WRF) model regional climate downscalings with differing lateral boundary conditions and microphysical parameterizations, and four gauge-based, interpolation-gridded precipitation datasets. Precipitation from these 10 datasets is evaluated against 95 snow pillows and a precipitation dataset inferred from stream gauges using a Bayesian inference method. During this water year, the gridded datasets tend to underestimate frozen precipitation on the windward slope of the Sierra Nevada, particularly in vicinity of Yosemite National Park. The WRF simulations with single-moment microphysics tend to overestimate precipitation throughout much of the region, whereas the WRF simulations with double-moment microphysics tend to better agree with both the snow pillows and inferred precipitation estimates, although they somewhat overestimate windward/leeside precipitation contrast in the northern Sierra Nevada. In addition, the WRF simulations, in particular those with single-moment microphysics, better distinguish wet-versus-dry pillows and watersheds than the gridded estimates.

  6. TRMM Common Microphysics Products: A Tool for Evaluating Spaceborne Precipitation Retrieval Algorithms.

    NASA Astrophysics Data System (ADS)

    Kingsmill, David E.; Yuter, Sandra E.; Heymsfield, Andrew J.; Hobbs, Peter V.; Korolev, Alexei V.; L, Stith Jeffrey; Bansemer, Aaron; Haggerty, Julie A.; Rangno, Arthur L.

    2004-11-01

    A customized product for analysis of microphysics data collected from aircraft during field campaigns in support of the Tropical Rainfall Measuring Mission (TRMM) program is described. These “common microphysics products” (CMPs) are designed to aid in evaluation of TRMM spaceborne precipitation retrieval algorithms. Information needed for this purpose (e.g., particle size spectra and habit, liquid and ice water content) was derived by using a common processing strategy on the wide variety of microphysical instruments and raw native data formats employed in the field campaigns. The CMPs are organized into an American Standard Code for Information Interchange (ASCII) structure to allow easy access to the data for those less familiar with microphysical data processing and without the tools to accomplish it. Detailed examples of the CMP show its potential and some of its limitations. This approach may be a first step toward developing a generalized microphysics format and an associated community-oriented, nonproprietary software package for microphysics data processing—initiatives that would likely broaden community access to, and use of, microphysics datasets.


  7. Hydrologic Assessment of Remotely Sensed High Resolution Precipitation Products over Cold-Mountainous Regions, and Analysis of the GPM Impact

    NASA Astrophysics Data System (ADS)

    Behrangi, A.; Andreadis, K.; Fisher, J. B.; Turk, F. J.; Painter, T. H.; Granger, S. L.; Das, N. N.; Stephens, G. L.

    2014-12-01

    Remote sensing of precipitation in mountainous and snow-fed basins is challenging, but critical for hydrometeorological applications and water resources management. This study is part of the ongoing effort to develop a Regional Hydrological Extremes Assessment System (RHEAS). Five commonly used satellite-based high-resolution precipitation products (HRPPs) over several basins in the mountainous western United States are investigated. The products (TRMM 3B42, TRMM 3B42-RT, CMORPH, PERSIANN, and PERSIANN-CCS) are analyzed using ground gauge and gauge-adjusted radar precipitation data. In order to diagnose the sources of errors, level 2 products are also explored (AMSR, AMSU, TRMM TMI, TRMM PR, and CloudSat). CloudSat provided useful insight on light rain and snowfall and was used as an additional resource to improve the analysis. For hydrologic assessment, the skill of HRPPs and the resulting streamflow simulations from the Variable Infiltration Capacity (VIC) hydrological model is cross-compared. It was found that over the mountainous west US basins, HRPPs often capture major precipitation events, but seldom capture the observed magnitude of precipitation, especially during winter when snowfall is dominant. Bias adjustment is found to be effective in enhancing the HRPPs and resulting streamflow simulations. The results using collocated AMSR-E, CloudSat, and AMSU suggest that current limitations in retrieving snowfall, precipitation from systems that lack frozen hydrometeors, and systems over frozen land contribute largely to the observed errors transferred to HRPPs. In light of the operation of the GPM mission, further opportunities for enhancing snowfall retrieval and hydrology of cold and mountainous regions are becoming available. We provide some initial assessment of the latest GPM observations and discuss about the impact of GPM over cold-mountainous basins.

  8. Dynamic microbial community associated with iron-arsenic co-precipitation products from a groundwater storage system in Bangladesh.

    PubMed

    Gorra, Roberta; Webster, Gordon; Martin, Maria; Celi, Luisella; Mapelli, Francesca; Weightman, Andrew J

    2012-07-01

    The prokaryotic community in Fe-As co-precipitation product from a groundwater storage tank in Bangladesh was investigated over a 5-year period to assess the diversity of the community and to infer biogeochemical mechanisms that may contribute to the formation and stabilisation of co-precipitation products and to Fe and As redox cycling. Partial 16S rRNA gene sequences from Bacteria and Archaea, functional markers (mcrA and dsrB) and iron-oxidising Gallionella-related 16S rRNA gene sequences were determined using denaturing gradient gel electrophoresis (DGGE). Additionally, a bacterial 16S rRNA gene library was also constructed from one representative sample. Biogeochemical characterization demonstrated that co-precipitation products consist of a mixture of inorganic minerals, mainly hydrous ferric oxides, intimately associated with organic matter of microbial origin that contribute to the chemical and physical stabilisation of a poorly ordered structure. DGGE analysis and polymerase chain reaction-cloning revealed that the diverse bacterial community structure in the co-precipitation product progressively stabilised with time resulting in a prevalence of methylotrophic Betaproteobacteria, while the archaeal community was less diverse and was dominated by members of the Euryarchaeota. Results show that Fe-As co-precipitation products provide a habitat characterised by anoxic/oxic niches that supports a phylogenetically and metabolically diverse group of prokaryotes involved in metal, sulphur and carbon cycling, supported by the presence of Gallionella-like iron-oxidizers, methanogens, methylotrophs, and sulphate reducers. However, no phylotypes known to be directly involved in As(V) respiration or As(III) oxidation were found.

  9. Development of Deep Learning Based Data Fusion Approach for Accurate Rainfall Estimation Using Ground Radar and Satellite Precipitation Products

    NASA Astrophysics Data System (ADS)

    Chen, H.; Chandra, C. V.; Tan, H.; Cifelli, R.; Xie, P.

    2016-12-01

    Rainfall estimation based on onboard satellite measurements has been an important topic in satellite meteorology for decades. A number of precipitation products at multiple time and space scales have been developed based upon satellite observations. For example, NOAA Climate Prediction Center has developed a morphing technique (i.e., CMORPH) to produce global precipitation products by combining existing space based rainfall estimates. The CMORPH products are essentially derived based on geostationary satellite IR brightness temperature information and retrievals from passive microwave measurements (Joyce et al. 2004). Although the space-based precipitation products provide an excellent tool for regional and global hydrologic and climate studies as well as improved situational awareness for operational forecasts, its accuracy is limited due to the sampling limitations, particularly for extreme events such as very light and/or heavy rain. On the other hand, ground-based radar is more mature science for quantitative precipitation estimation (QPE), especially after the implementation of dual-polarization technique and further enhanced by urban scale radar networks. Therefore, ground radars are often critical for providing local scale rainfall estimation and a "heads-up" for operational forecasters to issue watches and warnings as well as validation of various space measurements and products. The CASA DFW QPE system, which is based on dual-polarization X-band CASA radars and a local S-band WSR-88DP radar, has demonstrated its excellent performance during several years of operation in a variety of precipitation regimes. The real-time CASA DFW QPE products are used extensively for localized hydrometeorological applications such as urban flash flood forecasting. In this paper, a neural network based data fusion mechanism is introduced to improve the satellite-based CMORPH precipitation product by taking into account the ground radar measurements. A deep learning system is

  10. Validation of satellite OPEMW precipitation product with ground-based weather radar and rain gauge networks

    NASA Astrophysics Data System (ADS)

    Cimini, D.; Romano, F.; Ricciardelli, E.; Di Paola, F.; Viggiano, M.; Marzano, F. S.; Colaiuda, V.; Picciotti, E.; Vulpiani, G.; Cuomo, V.

    2013-11-01

    The Precipitation Estimation at Microwave Frequencies (PEMW) algorithm was developed at the Institute of Methodologies for Environmental Analysis of the National Research Council of Italy (IMAA-CNR) for inferring surface rain intensity (sri) from satellite passive microwave observations in the range from 89 to 190 GHz. The operational version of PEMW (OPEMW) has been running continuously at IMAA-CNR for two years. The OPEMW sri estimates, together with other precipitation products, are used as input to an operational hydrological model for flood alert forecast. This paper presents the validation of OPEMW against simultaneous ground-based observations from a network of 20 weather radar systems and a network of more than 3000 rain gauges distributed over the Italian Peninsula and main islands. The validation effort uses a data set covering one year (July 2011-June 2012). The effort evaluates dichotomous and continuous scores for the assessment of rain detection and quantitative estimate, respectively, investigating both spatial and temporal features. The analysis demonstrates 98% accuracy in correctly identifying rainy and non-rainy areas; it also quantifies the increased ability (with respect to random chance) to detect rainy and non-rainy areas (0.42-0.45 Heidke skill score) or rainy areas only (0.27-0.29 equitable threat score). Performances are better than average during summer, fall, and spring, while worse than average in the winter season. The spatial-temporal analysis does not show seasonal dependence except over the Alps and northern Apennines during winter. A binned analysis in the 0-15 mm h-1 range suggests that OPEMW tends to slightly overestimate sri values below 6-7 mm h-1 and underestimate sri above those values. With respect to rain gauges (weather radars), the correlation coefficient is larger than 0.8 (0.9). The monthly mean difference and standard deviation remain within ±1 and 2 mm h-1 with respect to rain gauges (respectively -2-0 and 4 mm h-1

  11. Effect of V Precipitation on Continuously Cooled Sulfur-Lean Vanadium-Alloyed Steels for Long Products Applications

    NASA Astrophysics Data System (ADS)

    Capdevila, C.; García-Mateo, C.; Cornide, J.; Chao, J.; Caballero, F. G.

    2011-12-01

    The acicular ferrite formation as decomposition product of S-lean V-alloyed austenite with high N content is studied in this article. A combination of thermodynamic models as well as some physical metallurgical principles was used to analyze the intragranular nucleation potency of V(C,N) precipitates. The designed thermomechanical and heat treatments ensure an almost homogeneous microstructure consisting of acicular ferrite for this N-rich laboratory cast steel. The results presented in this work demonstrate that, in the absence of sulfide inclusions, acicular ferrite is nucleated on V(C,N) precipitates.

  12. NASA's modified Boeing 747 Shuttle Carrier Aircraft with the Space Shuttle Endeavour on top lifts off to begin its ferry flight back to the Kennedy Space Center in Florida

    NASA Image and Video Library

    2001-05-08

    NASA's modified Boeing 747 Shuttle Carrier Aircraft with the Space Shuttle Endeavour on top lifts off from Edwards Air Force Base to begin its ferry flight back to the Kennedy Space Center in Florida.

  13. Geochemical modeling of the influence of silicate mineral alteration on alkalinity production and carbonate precipitation

    NASA Astrophysics Data System (ADS)

    Herda, Gerhard; Kraemer, Stephan M.; Gier, Susanne; Meister, Patrick

    2016-04-01

    High CO2 partial pressure (pCO2) in deep rock reservoirs causes acidification of the porefluid. Such conditions occur during injection and subsurface storage of CO2 (to prevent the release of greenhouse gas) but also naturally in zones of strong methanogenic microbial activity in organic matter-rich ocean margin sediments. The acidic fluids are corrosive to carbonates and bear the risk of leakage of CO2 gas to the surface. Porefluid acidification may be moderated by processes that increase the alkalinity, i.e. that produce weak acid anions capable of buffering the acidification imposed by the CO2. Often, alkalinity increases as a result of anaerobic microbial activity, such as anaerobic oxidation of methane. However, on a long term the alteration of silicates, in particular, clay minerals, may be a more efficient mechanism of alkalinity production. Under altered temperature, pressure and porefluid composition at depth, clay minerals may change to thermodynamically more stable states, thereby increasing the alkalinity of the porefluid by partial leaching of Mg-(OH)2 and Ca-(OH)2 (e.g. Wallmann et al., 2008; Mavromatis et al., 2014). This alteration may even be enhanced by a high pCO2. Thus, silicate alteration can be essential for a long-term stabilization of volatile CO2 in the form of bicarbonate or may even induce precipitation of carbonate minerals, but these processes are not fully understood yet. The goal of this study is to simulate the alkalinity effect of silicate alteration under diagenetic conditions and high pCO2 by geochemical modeling. We are using the program PHREEQC (Parkhurst and Appelo, 2013) to generate high rock/fluid ratio characteristics for deep subsurface rock reservoirs. Since we are interested in the long-term evolution of diagenetic processes, over millions of years, we do not consider kinetics but calculate the theoretically possible equilibrium conditions. In a first step we are calculating the saturation state of different clay minerals

  14. Precipitation Analysis at Fine Time Scales using TRMM and Other Satellites: Real-time and Research Products and Applications

    NASA Technical Reports Server (NTRS)

    Adler, Robert; Huffman, George; Bolvin, David; Nelkin, Eric; Curtis, Scott; Pierce, Harold; Gu, Guo-Jon

    2004-01-01

    Quasi-global precipitation analyses at fine time scales (3-hr) are described. TRMM observations (radar and passive microwave) are used to calibrate polar-orbit microwave observations from SSM/I (and other satellites instruments, including AMSR and AMSU) and geosynchronous IR observations. The individual data sets are then merged using a priority order based on quality to form the TRMM Multi-satellite Precipitation Analysis (MPA). Raingauge information is used to help constrain the satellite-based estimates over land. The TRMM standard research product (Version 6 3B-42 of the TRMM products) will be available for the entire TRMM period (January 1998-present) by the end of 2004. The real-time version of this merged product has been produced over the past two years and is available on the U.S. TRMM web site (trmm.gsfc.nasa.gov) at 0.25" latitude-longitude resolution over the latitude range from 5O0N-50"S. Validation of daily totals indicates good results, with limitations noted in mid-latitude winter over land and regions of shallow, orographic precipitation. Various applications of these estimates are described, includmg: 1) detecting potential floods in near real-time; 2) analyzing Indian Ocean precipitation variations related to the initiation of El Nino; 3) determining characteristics of the African monsoon; and 4) analysis of diurnal variations.

  15. Precipitation Analysis at Fine Time Scales using TRMM and Other Satellites: Realtime and Research Products and Applications

    NASA Technical Reports Server (NTRS)

    Adler, Robert; Huffman, George; Bolvin, David; Nelkin, Eric; Curtis, Scott; Pierce, Harold; Gu, Guojon

    2004-01-01

    Quasi-global precipitation analyses at fine time scales (3-hr) are described. TRMM observations (radar and passive microwave) are used to calibrate polar-orbit microwave observations from SSM/I (and other satellites instruments, including AMSR and AMSU) and geosynchronous IR observations. The individual data sets are then merged using a priority order based on quality to form the TRMM Multi-satellite Precipitation Analysis (MPA). Raingauge information is used to help constrain the satellite-based estimates over land. The TRMM standard research product (Version 6 3B-42 of the TRMM products) will be available for the entire TRMM period (January 1998-present) by the end of 2004. The real-time version of this merged product has been produced over the past two years and is available on the U.S. TRMM web site (trmm.gsfc.nasa.gov) at 0.25 deg latitude-longitude resolution over the latitude range from 50 deg N-50 deg S. Validation of daily totals indicates good results, with limitations noted in mid-latitude winter over land and regions of shallow, orographic precipitation. Various applications of these estimates are described, including: 1) detecting potential floods in near real-time; 2) analyzing Indian Ocean precipitation variations related to the initiation of El Nino; 3) determining characteristics of the African monsoon; and 4) analysis of diurnal variations.

  16. Precipitation Analysis at Fine Time Scales Using Multiple Satellites: Real-time and Research Products and Applications

    NASA Technical Reports Server (NTRS)

    Adler, Robert; Huffman, George; Bolvin, David; Nelkin, Eric; Curtis, Scott; Pierce, Harold

    2004-01-01

    Quasi-global precipitation analyses at fine time scales (3-hr) are described. TRMM observations (radar and passive microwave) are used to calibrate polar-orbit microwave observations from SSM/I (and other satellites instruments, including AMSR and AMSU) and geosynchronous IR observations. The individual data sets are then merged using a priority order based on quality to form the Multi-satellite Precipitation Analysis (MPA). Raingauge information is used to help constrain the satellite-based estimates over land. The TRMM standard research product (Version 6 3B-42 of the TRMM products) will be available for the entire TRMM period (January 1998-present) in 2004. The real-time version of this merged product has been produced over the past two years and is available on the U.S. TRMM web site (trmm.gsfc.nasa.gov) at 0.25" latitude-longitude resolution over the latitude range from 5O"N-5O0S. Validation of daily totals indicates good results, with limitations noted in mid-latitude winter over land and regions of shallow, orographic precipitation. Various applications of these estimates are described, including: 1) detecting potential floods in near real-time; 2) analyzing Indian Ocean precipitation variations related to the initiation of El Nino; 3) determining characteristics of the African monsoon; and 4) analysis of diurnal variations.

  17. Precipitation Analysis at Fine Time Scales using TRMM and Other Satellites: Realtime and Research Products and Applications

    NASA Technical Reports Server (NTRS)

    Adler, Robert; Huffman, George; Bolvin, David; Nelkin, Eric; Curtis, Scott; Pierce, Harold; Gu, Guojon

    2004-01-01

    Quasi-global precipitation analyses at fine time scales (3-hr) are described. TRMM observations (radar and passive microwave) are used to calibrate polar-orbit microwave observations from SSM/I (and other satellites instruments, including AMSR and AMSU) and geosynchronous IR observations. The individual data sets are then merged using a priority order based on quality to form the TRMM Multi-satellite Precipitation Analysis (MPA). Raingauge information is used to help constrain the satellite-based estimates over land. The TRMM standard research product (Version 6 3B-42 of the TRMM products) will be available for the entire TRMM period (January 1998-present) by the end of 2004. The real-time version of this merged product has been produced over the past two years and is available on the U.S. TRMM web site (trmm.gsfc.nasa.gov) at 0.25 deg latitude-longitude resolution over the latitude range from 50 deg N-50 deg S. Validation of daily totals indicates good results, with limitations noted in mid-latitude winter over land and regions of shallow, orographic precipitation. Various applications of these estimates are described, including: 1) detecting potential floods in near real-time; 2) analyzing Indian Ocean precipitation variations related to the initiation of El Nino; 3) determining characteristics of the African monsoon; and 4) analysis of diurnal variations.

  18. Precipitation Analysis at Fine Time Scales Using Multiple Satellites: Real-time and Research Products and Applications

    NASA Technical Reports Server (NTRS)

    Adler, Robert; Huffman, George; Bolvin, David; Nelkin, Eric; Curtis, Scott; Pierce, Harold

    2004-01-01

    Quasi-global precipitation analyses at fine time scales (3-hr) are described. TRMM observations (radar and passive microwave) are used to calibrate polar-orbit microwave observations from SSM/I (and other satellites instruments, including AMSR and AMSU) and geosynchronous IR observations. The individual data sets are then merged using a priority order based on quality to form the Multi-satellite Precipitation Analysis (MPA). Raingauge information is used to help constrain the satellite-based estimates over land. The TRMM standard research product (Version 6 3B-42 of the TRMM products) will be available for the entire TRMM period (January 1998-present) in 2004. The real-time version of this merged product has been produced over the past two years and is available on the U.S. TRMM web site (trmm.gsfc.nasa.gov) at 0.25" latitude-longitude resolution over the latitude range from 5O"N-5O0S. Validation of daily totals indicates good results, with limitations noted in mid-latitude winter over land and regions of shallow, orographic precipitation. Various applications of these estimates are described, including: 1) detecting potential floods in near real-time; 2) analyzing Indian Ocean precipitation variations related to the initiation of El Nino; 3) determining characteristics of the African monsoon; and 4) analysis of diurnal variations.

  19. Precipitation Analysis at Fine Time Scales using TRMM and Other Satellites: Real-time and Research Products and Applications

    NASA Technical Reports Server (NTRS)

    Adler, Robert; Huffman, George; Bolvin, David; Nelkin, Eric; Curtis, Scott; Pierce, Harold; Gu, Guo-Jon

    2004-01-01

    Quasi-global precipitation analyses at fine time scales (3-hr) are described. TRMM observations (radar and passive microwave) are used to calibrate polar-orbit microwave observations from SSM/I (and other satellites instruments, including AMSR and AMSU) and geosynchronous IR observations. The individual data sets are then merged using a priority order based on quality to form the TRMM Multi-satellite Precipitation Analysis (MPA). Raingauge information is used to help constrain the satellite-based estimates over land. The TRMM standard research product (Version 6 3B-42 of the TRMM products) will be available for the entire TRMM period (January 1998-present) by the end of 2004. The real-time version of this merged product has been produced over the past two years and is available on the U.S. TRMM web site (trmm.gsfc.nasa.gov) at 0.25" latitude-longitude resolution over the latitude range from 5O0N-50"S. Validation of daily totals indicates good results, with limitations noted in mid-latitude winter over land and regions of shallow, orographic precipitation. Various applications of these estimates are described, includmg: 1) detecting potential floods in near real-time; 2) analyzing Indian Ocean precipitation variations related to the initiation of El Nino; 3) determining characteristics of the African monsoon; and 4) analysis of diurnal variations.

  20. Examination of the jarosite-alunite precipitate addition in the raw meal for the production of sulfoaluminate cement clinker.

    PubMed

    Katsioti, M; Tsakiridis, P E; Leonardou-Agatzini, S; Oustadakis, P

    2006-04-17

    The aim of the present research work was to investigate the possibility of adding a jarosite-alunite chemical precipitate, a waste product of a new hydrometallurgical process developed to treat economically low-grade nickel oxides ores, in the raw meal for the production of sulfoaluminate cement clinker. For that reason, two samples of raw meals were prepared, one contained 20% gypsum, as a reference sample ((SAC)Ref) and another with 11.31% jarosite-alunite precipitate ((SAC)J/A). Both raw meals were sintered at 1300 degrees C. The results of chemical and mineralogical analyses as well as the microscopic examination showed that the use of the jarosite-alunite precipitate did not affect the mineralogical characteristics of the so produced sulfoaluminate cement clinker and there was confirmed the formation of the sulfoaluminate phase (C4A3S), the most typical phase of this cement type. Furthermore, both clinkers were tested by determining the grindability, setting time, compressive strength and expansibility. The hydration products were examined by XRD analysis at 2, 7, 28 and 90 days. The results of the physico-mechanical tests showed that the addition of jarosite-alunite precipitate did not negatively affect the quality of the produced cement.

  1. Convergence and contingency in production-precipitation relationships in North American and South African C4 grasslands.

    PubMed

    Knapp, Alan K; Burns, Catherine E; Fynn, Richard W S; Kirkman, Kevin P; Morris, Craig D; Smith, Melinda D

    2006-09-01

    Mesic grasslands in North America and South Africa share many structural attributes, but less is known of their functional similarities. We assessed the control of a key ecosystem process, aboveground net primary production (ANPP), by interannual variation in precipitation amount and pattern via analysis of data sets (15- and 24-year periods) from long-term research programs on each continent. Both sites were dominated by C(4) grasses and had similar growing season climates; thus, we expected convergence in precipitation-ANPP relationships. Lack of convergence, however, would support an alternative hypothesis-that differences in evolutionary history and purportedly greater climatic variability in South Africa fundamentally alter the functioning of southern versus northern hemisphere grasslands. Neither mean annual precipitation nor mean ANPP differed between the South African and North American sites (838 vs. 857 mm/year, 423.5 vs. 461.4 g/m(2) respectively) and growing season precipitation-ANPP relationships were similar. Despite overall convergence, there were differences between sites in how the seasonal timing of precipitation affected ANPP. In particular, interannual variability in precipitation that fell during the first half of the growing season strongly affected annual ANPP in South Africa (P < 0.01), but was not related to ANPP in North America (P = 0.098). Both sites were affected similarly by late season precipitation. Divergence in the seasonal course of available soil moisture (chronically low in the winter and early spring in the South African site vs. high in the North American site) is proposed as a key contingent factor explaining differential sensitivity in ANPP to early season precipitation in these two grasslands. These long-term data sets provided no support for greater rainfall, temperature or ANPP variability in the South African versus the North American site. However, greater sensitivity of ANPP to early season precipitation in the South

  2. Use of a byproduct of magnesium oxide production to precipitate phosphorus and nitrogen as struvite from wastewater treatment liquors.

    PubMed

    Quintana, Miguel; Colmenarejo, Manuel Fco; Barrera, Jesús; García, Gema; García, Elia; Bustos, Angel

    2004-01-28

    This paper describes a series of experiments designed to recover phosphorus and nitrogen from sewage in the form of struvite (MgNH(4)PO(4).6H(2)O), a potential fertilizer. Nitrogen and phosphate were recovered from a filtrate of digested sludge dewatered at the Arroyo del Soto Waste Water Treatment Plant (WWTP) (Madrid, Spain). A byproduct of the Spanish magnesite mining and MgO production industry was used as the magnesium source. The precipitating performance of this byproduct was compared to that of conventional chemical reagents such as pure MgO. The precipitates obtained were subjected to chemical, light microscopy, and X-ray diffraction analysis. The findings indicate the precipitate recovered using this byproduct contains several minerals with a predominance of struvite. Optimal purity ( approximately 80% struvite) was achieved using the sieved <0.04 mm grain size fraction of the byproduct at doses corresponding to a molar Mg:P ratio of 1.6.

  3. Multi-scale evaluation of high-resolution multi-sensor blended global precipitation products over the Yangtze River

    NASA Astrophysics Data System (ADS)

    Li, Zhe; Yang, Dawen; Hong, Yang

    2013-09-01

    In the present study, four high-resolution multi-sensor blended precipitation products, TRMM Multisatellite Precipitation Analysis (TMPA) research product (3B42 V7) and near real-time product (3B42 RT), Climate Prediction Center MORPHing technique (CMORPH) and Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN), are evaluated over the Yangtze River basin from April 2008 to March 2012 using the gauge data. This regional evaluation is performed at temporal scales ranging from annual to daily, based on a number of diagnostic statistics. Gauge adjustment greatly reduces the bias in 3B42 V7, a post real-time research product. Additionally, it helps the product maintain a stable skill level in winter. When additional indicators such as spatial correlation, Root Mean Square Error (RMSE), and Probability of Detection (POD) are considered, 3B42 V7 is not always superior to other products (especially CMORPH) at the daily scale. Among the near real-time datasets, 3B42 RT overestimates annual rainfall over the basin; CMORPH and PERSIANN underestimate it. In particular, the upper Yangtze always suffers from positive bias (>1 mm day-1) in the 3B42 RT dataset and negative bias (-0.2 to -1 mm day-1) in the CMORPH dataset. When seasonal scales are considered, CMORPH exhibits negative bias, mainly introduced during cold periods. The correlation between CMORPH and gauge data is the highest. On the contrary, the correlation between 3B42 RT and gauge data is more scattered; statistically, this results in lower bias. Finally, investigation of the probability distribution functions (PDFs) suggests that 3B42 V7 and 3B42 RT are consistently better at retrieving the PDFs in high-intensity events. Overall, this study provides useful information about the error characteristics associated with the four mainstream satellite precipitation products and their implications regarding hydrological applications over the Yangtze River basin.

  4. Evaluation of the latest satellite-gauge precipitation products and their hydrologic applications over the Huaihe River basin

    NASA Astrophysics Data System (ADS)

    Sun, Ruochen; Yuan, Huiling; Liu, Xiaoli; Jiang, Xiaoman

    2016-05-01

    Satellite-gauge quantitative precipitation estimate (QPE) products may reduce the errors in near real-time satellite precipitation estimates by combining rain gauge data, which provides great potential to hydrometeorological applications. This study aims to comprehensively evaluate four of the latest satellite-gauge QPEs, including NASA's Tropical Rainfall Measuring Mission (TRMM) 3B42V7 product, NOAA's Climate Prediction Center (CPC) MORPHing technique (CMORPH) bias-corrected product (CMORPH CRT), CMORPH satellite-gauge merged product (CMORPH BLD) and CMORPH satellite-gauge merged product developed at the National Meteorological Information Center (NMIC) of the China Meteorological Administration (CMA) (CMORPH CMA). These four satellite-gauge QPEs are statistically evaluated over the Huaihe River basin during 2003-2012 and applied into the distributed Variable Infiltration Capacity (VIC) model to assess hydrologic utilities. Compared to the China Gauge-based Daily Precipitation Analysis (CGDPA) newly developed at CMA/NMIC, the four satellite-gauge QPEs generally depict the spatial distribution well, with the underestimation in the southern mountains and overestimation in the northern plain of the Huaihe River basin. Specifically, both TRMM and CMORPH CRT adopt simple gauge adjustment algorithms and exhibit relatively poor performance, with evidently deteriorated quality in winter. In contrast, the probability density function-optimal interpolation (PDF-OI) gauge adjustment procedure has been applied in CMORPH BLD and CMORPH CMA, resulting in higher quality and more stable performance. CMORPH CMA further benefits from a merged dense gauge observation network and outperforms the other QPEs with significant improvements in rainfall amount and spatial/temporal distributions. Due to the insufficient gauge observations in the merging process, CMORPH BLD features the similar error characteristics of CMORPH CRT with a positive bias of light precipitation and a negative

  5. Advantages of using satellite soil moisture estimates over precipitation products to assess regional vegetation water availability and activity

    NASA Astrophysics Data System (ADS)

    Chen, Tiexi

    2017-04-01

    To improve the understanding of water-vegetation relationships, direct comparative studies assessing the utility of satellite remotely sensed soil moisture, gridded precipitation products, and land surface model output are needed. A case study was investigated for a water-limited, lateral inflow receiving area in northeastern Australia during December 2008 to May 2009. In January 2009, monthly precipitation showed strong positive anomalies, which led to strong positive soil moisture anomalies. The precipitation anomalies disappeared within a month. In contrast, the soil moisture anomalies persisted for months. Positive anomalies of Normalized Difference Vegetation Index (NDVI) appeared in February, in response to water supply, and then persisted for several months. In addition to these temporal characteristics, the spatial patterns of NDVI anomalies were more similar to soil moisture patterns than to those of precipitation and land surface model output. The long memory of soil moisture mainly relates to the presence of clay-rich soils. Modeled soil moisture from four of five global land surface models failed to capture the memory length of soil moisture and all five models failed to present the influence of lateral inflow. This case study indicates that satellite-based soil moisture is a better predictor of vegetation water availability than precipitation in environments having a memory of several months and thus is able to persistently affect vegetation dynamics. These results illustrate the usefulness of satellite remotely sensed soil moisture in ecohydrology studies. This case study has the potential to be used as a benchmark for global land surface model evaluations. The advantages of using satellite remotely sensed soil moisture over gridded precipitation products are mainly expected in lateral-inflow and/or clay-rich regions worldwide.

  6. Effect of Co-solutes on the Products and Solubility of Uranium(VI) Precipitated with Phosphate

    SciTech Connect

    Mehta, Vrajesh; Maillot, Fabien; Wang, Zheming; Catalano, Jeffrey G.; Giammar, Daniel E.

    2014-01-22

    Uranyl phosphate solids are often found with uranium ores, and their low solubility makes them promising target phases for in situ remediation of uranium-contaminated subsurface environments. The products and solubility of uranium(VI) precipitated with phosphate can be affected by the pH, dissolved inorganic carbon (DIC) concentration, and co-solute composition (e.g. Na+/Ca2+) of the groundwater. Batch experiments were performed to study the effect of these parameters on the products and extent of uranium precipitation induced by phosphate addition. In the absence of co-solute cations, chernikovite [H3O(UO2)(PO4)•3H2O] precipitated despite uranyl orthophosphate [(UO2)3(PO4)2•4H2O] being thermodynamically more favorable under certain conditions. As determined using X-ray diffraction, electron microscopy, and laser induced fluorescence spectroscopy, the presence of Na+ or Ca2+ as a co-solute led to the precipitation of sodium autunite ([Na2(UO2)2(PO4)2] and autunite [Ca(UO2)2(PO4)2]), which are structurally similar to chernikovite. In the presence of sodium, the dissolved U(VI) concentrations were generally in agreement with equilibrium predictions of sodium autunite solubility. However, in the calcium-containing systems, the observed concentrations were below the predicted solubility of autunite, suggesting the possibility of uranium adsorption to or incorporation in a calcium phosphate precipitate in addition to the precipitation of autunite.

  7. Development and evaluation of climatologically-downscaled AFWA AGRMET precipitation products over the continental U.S.

    NASA Astrophysics Data System (ADS)

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

    2008-05-01

    Collaborations between the Air Force Weather Agency (AFWA), the Hydrological Sciences Branch at NASA-GSFC, and the PRISM Group at 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 near-real-time simulations in regions of interest. This work focuses on value added to the AGRMET precipitation product by the inclusion of high-quality climatological information on a monthly time scale. The AGRMET method uses microwave-based satellite precipitation estimates from various polar-orbiting platforms (NOAA POES and DMSP), infrared-based estimates from geostationary platforms (GOES, METEOSAT, etc.), related cloud analysis products, and surface gauge observations in a complex and hierarchical blending process. Results from processing of the legacy AGRMET precipitation

  8. A new Grid Product of Tropical Cyclone Precipitation (TCP) for North America from 1930 to 2013

    NASA Astrophysics Data System (ADS)

    Zhu, L.

    2015-12-01

    We first developed a new method that collects daily TCP by using historical storm tracks and precipitation observation based on daily rain gauges in both U.S. and Mexico and calibrated it with satellite precipitation observation. We used a parametrized wind field to correct the possible under-estimations of precipitation in rain gauges. Grid interpolation parameters were optimized by testing different historical rain gauge densities and comparing our grid estimation of TCP and the observation from TRMM Multi-satellite Precipitation Analysis (3B42) by for the data available period from 1998 to 2013. The calibrated method was then used for the whole 94 years of TCP estimation. The preliminary result shows that the frequency of TCP events does not have significant change but the TCP intensity has significant increasing trends, especially in certain locations in North Carolina and Yucatan Peninsula in Mexico. This new long term TCP climatology can potentially assist model calibration and disaster prevention/mitigation.

  9. The precipitation products generation chain for the EUMETSAT Hydrological Satellite Application Facility at C.N.M.C.A.

    NASA Astrophysics Data System (ADS)

    Biron, Daniele; Melfi, Davide; Zauli, Francesco

    2008-08-01

    The EUMETSAT Satellite Application Facility in support to Hydrology (H-SAF) focuses on development of new geophysical products on precipitation, soil moisture and snow parameters and the utilisation of these parameters in hydrological models, NWP models and water management. The development phase of the H-SAF started in September 2005 under the leadership of Italian Meteorological Service. The "Centro Nazionale di Meteorologia e Climatologia Aeronautica (C.N.M.C.A.)", the Italian National Weather Centre, that physically hosts the generation chain of precipitation products, carried on activities to reach the final target: development of algorithms, validation of results, implementation of operative procedure to supply the service and to monitor the service performances. The paper shows the architectural status of the H-SAF precipitation group and stress the component of operations. It is shown the full correspondence with the EUMETSAT approved H-SAF documents, in particular the Algorithm Theoretical Design Document (ATDD), where products characteristics are referenced. Are also reported the first results, produced during the first H-SAF Workshop, held in Rome in October 2007, of validation activities performed on version 1 products, and last results of products distribution to beta-users in preparation of distributing version 2.

  10. Interactive Visualization of Near Real Time and Production Global Precipitation Measurement (GPM) Mission Data Online Using CesiumJS

    NASA Technical Reports Server (NTRS)

    Lammers, Matthew

    2016-01-01

    Advancements in the capabilities of JavaScript frameworks and web browsing technology make online visualization of large geospatial datasets viable. Commonly this is done using static image overlays, prerendered animations, or cumbersome geoservers. These methods can limit interactivity andor place a large burden on server-side post-processing and storage of data. Geospatial data, and satellite data specifically, benefit from being visualized both on and above a three-dimensional surface. The open-source JavaScript framework CesiumJS, developed by Analytical Graphics, Inc., leverages the WebGL protocol to do just that. It has entered the void left by the abandonment of the Google Earth Web API, and it serves as a capable and well-maintained platform upon which data can be displayed. This paper will describe the technology behind the two primary products developed as part of the NASA Precipitation Processing System STORM website: GPM Near Real Time Viewer (GPMNRTView) and STORM Virtual Globe (STORM VG). GPMNRTView reads small post-processed CZML files derived from various Level 1 through 3 near real-time products. For swath-based products, several brightness temperature channels or precipitation-related variables are available for animating in virtual real-time as the satellite-observed them on and above the Earths surface. With grid-based products, only precipitation rates are available, but the grid points are visualized in such a way that they can be interactively examined to explore raw values. STORM VG reads values directly off the HDF5 files, converting the information into JSON on the fly. All data points both on and above the surface can be examined here as well. Both the raw values and, if relevant, elevations are displayed. Surface and above-ground precipitation rates from select Level 2 and 3 products are shown. Examples from both products will be shown, including visuals from high impact events observed by GPM constellation satellites.

  11. Interactive Visualization of Near Real-Time and Production Global Precipitation Mission Data Online Using CesiumJS

    NASA Astrophysics Data System (ADS)

    Lammers, M.

    2016-12-01

    Advancements in the capabilities of JavaScript frameworks and web browsing technology make online visualization of large geospatial datasets viable. Commonly this is done using static image overlays, pre-rendered animations, or cumbersome geoservers. These methods can limit interactivity and/or place a large burden on server-side post-processing and storage of data. Geospatial data, and satellite data specifically, benefit from being visualized both on and above a three-dimensional surface. The open-source JavaScript framework CesiumJS, developed by Analytical Graphics, Inc., leverages the WebGL protocol to do just that. It has entered the void left by the abandonment of the Google Earth Web API, and it serves as a capable and well-maintained platform upon which data can be displayed. This paper will describe the technology behind the two primary products developed as part of the NASA Precipitation Processing System STORM website: GPM Near Real Time Viewer (GPMNRTView) and STORM Virtual Globe (STORM VG). GPMNRTView reads small post-processed CZML files derived from various Level 1 through 3 near real-time products. For swath-based products, several brightness temperature channels or precipitation-related variables are available for animating in virtual real-time as the satellite observed them on and above the Earth's surface. With grid-based products, only precipitation rates are available, but the grid points are visualized in such a way that they can be interactively examined to explore raw values. STORM VG reads values directly off the HDF5 files, converting the information into JSON on the fly. All data points both on and above the surface can be examined here as well. Both the raw values and, if relevant, elevations are displayed. Surface and above-ground precipitation rates from select Level 2 and 3 products are shown. Examples from both products will be shown, including visuals from high impact events observed by GPM constellation satellites.

  12. Newly Released Version 7 TRMM Multi-satellite Precipitation Analysis (TMPA) Products and Data Services at NASA GES DISC

    NASA Astrophysics Data System (ADS)

    Ostrenga, D.; Liu, Z.; Teng, W. L.; Kempler, S.

    2012-12-01

    The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) is home of global precipitation product archives, in particular, the Tropical Rainfall Measuring Mission (TRMM) products. TRMM is a joint U.S.-Japan satellite mission to monitor tropical and subtropical (40 Degrees S - 40 Degrees N) precipitation and to estimate its associated latent heating. The TRMM satellite provides the first detailed and comprehensive dataset on the four dimensional distribution of rainfall and latent heating over vastly undersampled tropical and subtropical oceans and continents. The TRMM satellite was launched on November 27, 1997. TRMM data products are archived at and distributed by GES DISC. The newly released Version 7 TRMM Multi-satellite Precipitation Analysis (TMPA) products consist of several important changes including 1) additional output fields including sensor-specific source and overpass times; 2) additional satellite input data; 3) uniformly reprocessed input data using current algorithms; 4) a new IR data set (Jan. 1998 - Feb 2000) was included; 5) use of a single, uniformly processed gauge analysis; and 6) use of a latitude-band calibration scheme for all satellites. More details will be presented. Several new parameters have been included, such as, gauge relative weighting in 3B43, HQ and IR precipitation in 3B42. Data services include online tools and information web pages. The online tools are: 1) Mirador (http://mirador.gsfc.nasa.gov/), a simplified interface for searching, browsing, and ordering Earth science data at NASA Goddard Earth Sciences Data and Information Services Center (GES DISC). Mirador is designed to be fast and easy to learn; 2) Giovanni TOVAS (http://disc.sci.gsfc.nasa.gov/precipitation/tovas); 3) Simple Subset Wizard for TMPA data subsetting and format conversion; 4) Data via OPeNDAP (http://disc.sci.gsfc.nasa.gov/services/opendap/). The OPeNDAP provides remote access to individual variables within datasets in a form usable

  13. Newly Released TRMM Version 7 Products, GPCP Version 2.2 Precipitation Dataset and Data Services at NASA GES DISC

    NASA Astrophysics Data System (ADS)

    Ostrenga, D.; Liu, Z.; Teng, W. L.; Trivedi, B.; Kempler, S.

    2011-12-01

    The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) is home of global precipitation product archives, in particular, the Tropical Rainfall Measuring Mission (TRMM) products. TRMM is a joint U.S.-Japan satellite mission to monitor tropical and subtropical (40deg S - 40deg N) precipitation and to estimate its associated latent heating. The TRMM satellite provides the first detailed and comprehensive dataset on the four dimensional distribution of rainfall and latent heating over vastly undersampled tropical and subtropical oceans and continents. The TRMM satellite was launched on November 27, 1997. TRMM data products are archived at and distributed by GES DISC. The newly released TRMM Version 7 consists of several changes including new parameters, new products, meta data, data structures, etc. For example, hydrometeor profiles in 2A12 now have 28 layers (14 in V6). New parameters have been added to several popular Level-3 products, such as, 3B42, 3B43. Version 2.2 of the Global Precipitation Climatology Project (GPCP) dataset has been added to the TRMM Online Visualization and Analysis System (TOVAS; URL: http://disc2.nascom.nasa.gov/Giovanni/tovas/), allowing online analysis and visualization without downloading data and software. The GPCP dataset extends back to 1979. Results of basic intercomparison between the new and the previous versions of both TRMM and GPCP will be presented to help understand changes in data product characteristics. To facilitate data and information access and support precipitation research and applications, we have developed a Precipitation Data and Information Services Center (PDISC; URL: http://disc.gsfc.nasa.gov/precipitation). In addition to TRMM, PDISC provides current and past observational precipitation data. Users can access precipitation data archives consisting of both remote sensing and in-situ observations. Users can use these data products to conduct a wide variety of activities, including case

  14. Quantifying discharge uncertainty from remotely sensed precipitation data products in Puerto Rico

    NASA Astrophysics Data System (ADS)

    Weerasinghe, H.; Raoufi, R.; Yoon, Y.; Beighley, E., II; Alshawabkeh, A.

    2014-12-01

    Preterm birth is a serious health issue in the United States that contributes to over one-third of all infant deaths. Puerto Rico being one of the hot spots, preliminary research found that the high preterm birth rate can be associated with exposure to some contaminants in water used on daily basis. Puerto Rico has more than 200 contaminated sites including 16 active Superfund sites. Risk of exposure to contaminants is aggravated by unlined landfills lying over the karst regions, highly mobile and dynamic nature of the karst aquifers, and direct contact with surface water through sinkholes and springs. Much of the population in the island is getting water from natural springs or artesian wells that are connected with many of these potentially contaminated karst aquifers. Mobility of contaminants through surface water flows and reservoirs are largely known and are highly correlated with the variations in hydrologic events and conditions. In this study, we quantify the spatial and temporal distribution of Puerto Rico's surface water stores and fluxes to better understand potential impacts on the distribution of groundwater contamination. To quantify and characterize Puerto Rico's surface waters, hydrologic modeling, remote sensing and field measurements are combined. Streamflow measurements are available from 27 U.S. Geological Survey (USGS) gauging stations with drainage areas ranging from 2 to 510 km2. Hillslope River Routing (HRR) model is used to simulate hourly streamflow from watersheds larger than 1 km2 that discharge to ocean. HRR model simulates vertical water balance, lateral surface and subsurface runoff and river discharge. The model consists of 4418 sub-catchments with a mean model unit area (i.e., sub-catchment) of 1.8 km2. Using gauged streamflow measurements for validation, we first assess model results for simulated discharge using three precipitation products: TRMM-3B42 (3 hour temporal resolution, 0.25 degree spatial resolution); NWS stage

  15. Precipitation and Topography as Drivers of Tree Water Use and Productivity at Multiple Scales

    NASA Astrophysics Data System (ADS)

    Martin, J. T.; Hu, J.; Looker, N. T.; Jencso, K. G.

    2014-12-01

    Water is commonly the primary limiting factor for tree growth in semi-arid regions of the Western U.S. and tree productivity can vary drastically across landscapes as a function of water availability. The role of topography as a first order control on soil and ground water has been well studied; however, the strategies trees use to cope with water limitation in different landscape positions and across time remain unclear. As growing seasons progress, the availability of water changes temporally, as water inputs transition from snowmelt to rainfall, and spatially, as divergent positions dry more than convergent ones. We seek to understand how the interaction of these processes dictate where trees access water and which strategies most successfully avert water limitation of growth. We take advantage of clear differences in the isotopic signatures of snow and summer rain to track water utilized by Douglas fir, Ponderosa pine, Subalpine fir, Engelmann spruce, and Western larch in both convergent and divergent landscape positions and across time. We couple these data with evidence of growth limitation inferred from reductions in lateral growth rates observed by continuous dendrometer measurements to link tree water use and productivity. Xylem waters reflect both the precipitation type and soil profile distribution of water used by trees for growth and dendrometer measurements reflect the effects of water limitation through changes in the lateral growth curve as soil moistures decline. Isotope signatures from rain, snow and stream water fell predictably along the local meteoric water line with values from xylem samples falling between those of rain and snow. Trees on southern aspects exhibit more growth limitation in divergent than convergent positions while this effect appears muted or non-existent on northern aspects. Trees in convergent hollow positions rely more on snow water while trees on slopes utilize more rain water. Surprisingly, trees at lower elevation rely

  16. Evaluation of high resolution global satellite precipitation products using daily raingauge data over the Upper Blue Nile Basin

    NASA Astrophysics Data System (ADS)

    Sahlu, Dejene; Moges, Semu; Anagnostou, Emmanouil; Nikolopoulos, Efthymios; Hailu, Dereje; Mei, Yiwen

    2017-04-01

    Water resources assessment, planning and management in Africa is often constrained by the lack of reliable spatio-temporal rainfall data. Satellite products are steadily growing and offering useful alternative datasets of rainfall globally. The aim of this paper is to examine the error characteristics of the main available global satellite precipitation products with the view of improving the reliability of wet season (June to September) and small rainy season rainfall datasets over the Upper Blue Nile Basin. The study utilized six satellite derived precipitation datasets at 0.25-deg spatial grid size and daily temporal resolution:1) the near real-time (3B42_RT) and gauge adjusted (3B42_V7) products of Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA), 2) gauge adjusted and unadjusted Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN) products and 3) the gauge adjusted and un-adjusted product of the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center Morphing technique (CMORPH) over the period of 2000 to 2013.The error analysis utilized statistical techniques using bias ratio (Bias), correlation coefficient (CC) and root-mean-square-error (RMSE). Mean relative error (MRE), CC and RMSE metrics are further examined for six categories of 10th, 25th, 50th, 75th, 90thand 95th percentile rainfall thresholds. The skill of the satellite estimates is evaluated using categorical error metrics of missed rainfall volume fraction (MRV), falsely detected rainfall volume fraction (FRV), probability of detection (POD) and False Alarm Ratio (FAR). Results showed that six satellite based rainfall products underestimated wet season (June to September) gauge precipitation, with the exception of non-adjusted PERSIANN that overestimated the initial part of the rainy season (March to May). During the wet season, adjusted CMORPH has relatively better bias ratio (89

  17. Solubility product constants of covellite and a poorly crystalline copper sulfide precipitate at 298 K

    SciTech Connect

    Shea, D.; Helz, G.R. )

    1989-02-01

    The equilibrium constant at 25{degree}C for the following reaction has been measured in NaCl media by indirect methods where CuS (cov) designates synthetic covellite. Values of pK{sub sp} are 21.39, 21.04 and 20.95 at NaCl = 0.2, 0.7 and 1.0 M, respectively; the uncertainty in these K{sub sp} values is {plus minus} 0.15. The free energy of formation of covellite, for which published values are discordant, is calculated to be {minus}11.83 {plus minus} 0.4 kcal/mole at 298 K. This value is obtained by extrapolating the measured pK{sub sp} values to infinite dilution with corrections for Cl{sup {minus}} complexing. Applying similar Cl{sup {minus}} complexing corrections, based on recent measurements by Seward, to previously published solubility data for galena yields a revised pK{sup 0}{sub sp} for galena of 12.78. A poorly crystalline precipitate, obtained by mixing Cu{sup 2+} and HS{sup {minus}} solutions, yielded a reversible solubility product 3 orders of magnitude greater than that of covellite but about 3 orders of magnitude less than that of a truly amorphous phase, super-cooled liquid CuS. The poorly crystalline phase has not been studied previously. Its bulk composition was Cu{sub 1.18}S and Cu{sub 1.32}S, but microprobe analysis revealed that it was a partially exsolved mixture of roughly Cu{sub 1.11}S and Cu{sup 1.32}S. It was kinetically unstable, and converted to covellite when thermally annealed or when exposed to polysulfide solutions. Because of its instability, a material of this nature is likely to account for the amorphous copper sulfide alleged to occur in the Red Sea Brine deposits. However, it is possible that on short time scales dissolved Cu in sulfidic waters is controlled by metastable, rather than stable phases, as is known the the case with dissolved Fe.

  18. Evaluation of GPM-based Multi-satellite IMERG Precipitation Products Over the Lower Colorado River Basin, Texas

    NASA Astrophysics Data System (ADS)

    Omranian, S. E.; Sharif, H. O.

    2016-12-01

    This study evaluates the Global Precipitation Measurement (GPM) satellite products by analyzing extreme rainfall events over the Lower Colorado River Basin, Texas that resulted in unprecedented flash floods in May 2015. Records of a dense rain gauge network (241 stations) are compared with Integrated Multi-satellite Retrievals for GPM (IMERG) products. The spatial resolution of the GPM satellite product is 0.1º x 0.1º and the temporal resolution is 30 minutes. Reference gauge-based observations are distributed through the basin with total area of over 5,000 square kilometers at 15-minute time intervals. A preliminary assessment of GPM-based IMERG precipitation products shows reasonable correlation, especially when for periods of high amounts of rainfall. the results indicate that GPM satellite products can potentially be employed in hydrologic modeling, especially for large events. Moreover, since the IMERG products have semi-global coverage, it can be extremely useful in hydrological modeling and analysis studies over ungauged or poorly gauged regions.

  19. Dominant plant taxa predict plant productivity responses to CO2 enrichment across precipitation and soil gradients

    USDA-ARS?s Scientific Manuscript database

    The responses of water-limited ecosystems to rising atmospheric CO2 concentration (eCO2) depend on the supply and availability of soil moisture and on change in abundance of dominant plant taxa. Soil moisture supply and availability depends primarily on precipitation amount and soil texture. Respo...

  20. Differential relationships of livestock production and seasonal precipitation for three grazing intensities in shortgrass steppe

    USDA-ARS?s Scientific Manuscript database

    Long-term experiments have substantial utility for determining relationships of livestock weight gains to seasonal precipitation which can provide valuable understanding pertinent to the potential consequences of climate variability. A long-term (1939-2008, 70 years) data record of yearling Hereford...

  1. Nickel sulfide formation at low temperature: initial precipitates, solubility and transformation products

    EPA Science Inventory

    The formation of nickel sulfides has been examined experimentally over the temperature range from 25 to 60°C. At all conditions studied, hexagonal (α-NiS) was the initial precipitate from solution containing Ni2+ and dissolved sulfide. The formation of millerite (β- NiS, rhombo...

  2. Nickel sulfide formation at low temperature: initial precipitates, solubility and transformation products

    EPA Science Inventory

    The formation of nickel sulfides has been examined experimentally over the temperature range from 25 to 60°C. At all conditions studied, hexagonal (α-NiS) was the initial precipitate from solution containing Ni2+ and dissolved sulfide. The formation of millerite (β- NiS, rhombo...

  3. MWRRET Value-Added Product: The Retrieval of Liquid Water Path and Precipitable Water Vapor from Microwave Radiometer (MWR) Datasets

    SciTech Connect

    KL Gaustad; DD Turner

    2007-09-30

    This report provides a short description of the Atmospheric Radiation Measurement (ARM) microwave radiometer (MWR) RETrievel (MWRRET) Value-Added Product (VAP) algorithm. This algorithm utilizes complimentary physical and statistical retrieval methods and applies brightness temperature offsets to reduce spurious liquid water path (LWP) bias in clear skies resulting in significantly improved precipitable water vapor (PWV) and LWP retrievals. We present a general overview of the technique, input parameters, output products, and describe data quality checks. A more complete discussion of the theory and results is given in Turner et al. (2007b).

  4. Effects of Reduced Summer Precipitation on Productivity and Forage Quality of Floodplain Meadows at the Elbe and the Rhine River

    PubMed Central

    Ludewig, Kristin; Donath, Tobias W.; Zelle, Bianka; Eckstein, R. Lutz; Mosner, Eva; Otte, Annette; Jensen, Kai

    2015-01-01

    Background Floodplain meadows along rivers are semi-natural habitats and depend on regular land use. When used non-intensively, they offer suitable habitats for many plant species including rare ones. Floodplains are hydrologically dynamic ecosystems with both periods of flooding and of dry conditions. In German floodplains, dry periods may increase due to reduced summer precipitation as projected by climate change scenarios. Against this background, the question arises, how the forage quantity and quality of these meadows might change in future. Methods We report results of two field trials that investigated effects of experimentally reduced summer precipitation on hay quantity and quality of floodplain meadows at the Rhine River (2011-2012) and at two Elbe tributaries (2009-2011). We measured annual yield, the amount of hay biomass, and contents of crude protein, crude fibre, energy, fructan, nitrogen, phosphorus, and potassium. Results The annual yield decreased under precipitation reduction at the Rhine River. This was due to reduced productivity in the second cut hay at the Rhine River in which, interestingly, the contents of nitrogen and crude protein increased. The first cut at the Rhine River was unaffected by the treatments. At the Elbe tributaries, the annual yield and the hay quantity and quality of both cuts were only marginally affected by the treatments. Conclusion We conclude that the yield of floodplain meadows may become less reliable in future since the annual yield decreased under precipitation reduction at the Rhine River. However, the first and agriculturally more important cut was almost unaffected by the precipitation reduction, which is probably due to sufficient soil moisture from winter/spring. As long as future water levels of the rivers will not decrease during spring, at least the use of the hay from the first cut of floodplain meadows appears reliable under climate change. PMID:25950730

  5. Characterization of the reaction products and precipitates at the interface of carbon fiber reinforced magnesium–gadolinium composite

    SciTech Connect

    Wang, Yaping; Jiang, Longtao; Chen, Guoqin; Lin, Xiu; Zhang, Shaofeng; Pei, Risheng; Wu, Gaohui

    2016-03-15

    In the present work, carbon fiber reinforced magnesium-gadolinium composite was fabricated by pressure infiltration method. The phase composition, micro-morphology, and crystal structure of reaction products and precipitates at the interface of the composite were investigated. Scanning electron microscopy and energy dispersive spectroscopy analysis revealed the segregation of gadolinium element at the interface between carbon fiber and matrix alloy. It was shown that block-shaped Gd4C5, GdC2 and nano-sized Gd2O3 were formed at the interface during the fabrication process due to the interfacial reaction. Furthermore, magnesium-gadolinium precipitates including needle-like Mg5Gd (or Mg24Gd5) and thin plate-shaped long period stacking-ordered phase, were also observed at the interface and in the matrix near the interface. The interfacial microstructure and bonding mode were influenced by these interfacial products, which were beneficial for the improvement of the interfacial bonding strength. - Highlights: • Gadolinium element segregated on the surface of carbon fibers. • Block-shaped Gd{sub 4}C{sub 5} and GdC{sub 2} were formed at the interface via chemical reaction. • Gadolinium and oxygen reacted at the interface and formed nano-scaled Gd{sub 2}O{sub 3}. • The precipitates formed in the interface were identified to be Mg{sub 5}Gd (or Mg{sub 24}Gd{sub 5}) and plate-shaped long period stacking-ordered phase.

  6. Waste oil shale ash as a novel source of calcium for precipitated calcium carbonate: carbonation mechanism, modeling, and product characterization.

    PubMed

    Velts, O; Uibu, M; Kallas, J; Kuusik, R

    2011-11-15

    In this paper, a method for converting lime-containing oil shale waste ash into precipitated calcium carbonate (PCC), a valuable commodity is elucidated. The mechanism of ash leachates carbonation was experimentally investigated in a stirred semi-batch barboter-type reactor by varying the CO(2) partial pressure, gas flow rate, and agitation intensity. A consistent set of model equations and physical-chemical parameters is proposed to describe the CaCO(3) precipitation process from oil shale ash leachates of complex composition. The model enables the simulation of reactive species (Ca(2+), CaCO(3), SO(4)(2-), CaSO(4), OH(-), CO(2), HCO(3)(-), H(+), CO(3)(2-)) concentration profiles in the liquid, gas, and solid phases as well as prediction of the PCC formation rate. The presence of CaSO(4) in the product may also be evaluated and used to assess the purity of the PCC product. A detailed characterization of the PCC precipitates crystallized from oil shale ash leachates is also provided. High brightness PCC (containing up to ∼ 96% CaCO(3)) with mean particle sizes ranging from 4 to 10 μm and controllable morphology (such as rhombohedral calcite or coexisting calcite and spherical vaterite phases) was obtained under the conditions studied. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Sensitivity of seasonal weather prediction and extreme precipitation events to soil moisture initialization uncertainty using SMOS soil moisture products

    NASA Astrophysics Data System (ADS)

    Khodayar-Pardo, Samiro; Lopez-Baeza, Ernesto; Coll Pajaron, M. Amparo

    Sensitivity of seasonal weather prediction and extreme precipitation events to soil moisture initialization uncertainty using SMOS soil moisture products (1) S. Khodayar, (2) A. Coll, (2) E. Lopez-Baeza (1) Institute for Meteorology and Climate Research, Karlsruhe Institute of Technology (KIT), Karlsruhe Germany (2) University of Valencia. Earth Physics and Thermodynamics Department. Climatology from Satellites Group Soil moisture is an important variable in agriculture, hydrology, meteorology and related disciplines. Despite its importance, it is complicated to obtain an appropriate representation of this variable, mainly because of its high temporal and spatial variability. SVAT (Soil-Vegetation-Atmosphere-Transfer) models can be used to simulate the temporal behaviour and spatial distribution of soil moisture in a given area and/or state of the art products such as the soil moisture measurements from the SMOS (Soil Moisture and Ocean Salinity) space mission may be also convenient. The potential role of soil moisture initialization and associated uncertainty in numerical weather prediction is illustrated in this study through sensitivity numerical experiments using the SVAT SURFEX model and the non-hydrostatic COSMO model. The aim of this investigation is twofold, (a) to demonstrate the sensitivity of model simulations of convective precipitation to soil moisture initial uncertainty, as well as the impact on the representation of extreme precipitation events, and (b) to assess the usefulness of SMOS soil moisture products to improve the simulation of water cycle components and heavy precipitation events. Simulated soil moisture and precipitation fields are compared with observations and with level-1(~1km), level-2(~15 km) and level-3(~35 km) soil moisture maps generated from SMOS over the Iberian Peninsula, the SMOS validation area (50 km x 50 km, eastern Spain) and selected stations, where in situ measurements are available covering different vegetation cover

  8. A Rapid Protoyping Approach for the Evaluation of Potential GPM-Era Precipitation Products for Water Resources Management Applications

    NASA Astrophysics Data System (ADS)

    Anantharaj, V. G.; Houser, P. R.; Turk, F. J.; Peterson, C. A.; Hossain, F.; Moorhead, R. J.; Toll, D. L.; Mostovoy, G.

    2009-04-01

    societal benefits related to human health (soil moisture, climate and disease outbreak), homeland security (removal of chemical/biological/nuclear agents), flooding potential and warning, water availability, water quality, and agriculture and food security. In 2006, the NASA ASP sponsored two RPC experiments to evaluate potential GPM-era high resolution satellite precipitation products for water management applications. One of the current uncertainties involved in the GPM missions is the nature of the exact configuration of the constellations of satellites and hence the potential for the dynamic error characteristics over time of the precipitation estimates. For the RPC evaluations, we needed a satellite precipitation product that would be analogous to the GPM-era products. Our solution was to develop a suite of high resolution precipitation products, based on the NRL-Blend algorithm. We created a set of 10 different satellite precipitation estimates (hereafter referred to as the "GPM-proxy data"), using the currently available IR and microwave sensors. However, in each product we systematically left out sets of observations and/or sensors, such as AM orbits. The geographical focus of our study was the operational domain of the Arkansas Basin River Forecast Center (ABRFC) of the U.S. National Weather Service. We have evaluated the GPM-proxy data against the operational product (radar and gauge based) used by ABRFC. Further, we also performed a set of soil water content (SWC) sensitivity experiments using the Noah and Mosaic Land Surface Models (LSM) to quantify the impacts on water management applications involving land surface hydrology. Both the LSMs were forced with the same set of GPM-proxy data. Though the overall spatial patterns for both the models were similar, there were subtle differences in the respective model sensitivities to the different precipitation forcings. These experimental results illustrate the need for comprehensive pre-evaluations of applications

  9. Error analysis of global satellite precipitation products using daily gauged observations over the upper central Blue Nile Basin

    NASA Astrophysics Data System (ADS)

    Sahlu, Dejene; Moges, Semu; Anagnostou, Emmanouil N.; Hailu, Dereje

    2015-04-01

    Water resource assessment, planning and management in Africa are often constrained due to lack of reliable spatio-temporal rainfall data. Satellite and global reanalysis products are steadily growing and offering useful alternative datasets of rainfall globally. Aim of this paper is to examine the error characteristics of the main available global satellite precipitation products with the view to improve the reliability of wet season (June to September) rainfall datasets over the upper Blue Nile Basin in Ethiopia. The study utilized six satellite derived precipitation datasets at 0.25-deg spatial grid size and daily temporal resolution:1) the near real-time (3B42_RT) and gauge adjusted (3B42_V7) products of Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA), 2) gauge adjusted and unadjusted Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN) products and 3) the gauge adjusted and un-adjusted product of the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center Morphing technique (CMORPH) over the period of 2000 to 2013. The historical daily rainfall data sets are chosen for the same period from 64 gauging stations which are within a mountainous area of about 45,000 km2. The elevation of gauges used in this error study ranged from 1800 to 3000 meters above sea level. The error analysis utilized statistical techniques of missed rainfall volume fraction (MRV), falsely detected rainfall volume fraction (FRV), mean relative error (MRE), bias ratio (Bias), coefficient of variation of error (CVE) and the trends of the error metrics with respect to elevation. The three error metrics, MRE, Bias and CVE are further examined for five rainfall thresholds associated with different percentile categories (2nd, 20th, 50th, 80th and 98th) . Results show that CMORPH has relatively lower MRV (~1.5 %) than the TRMM and PERSIANN products (10 -13 %.). Non-gauge adjusted

  10. Combined effects of precipitation and nitrogen deposition on native and invasive winter annual production in California deserts.

    PubMed

    Rao, Leela E; Allen, Edith B

    2010-04-01

    Primary production in deserts is limited by soil moisture and N availability, and thus is likely to be influenced by both anthropogenic N deposition and precipitation regimes altered as a consequence of climate change. Invasive annual grasses are particularly responsive to increases in N and water availabilities, which may result in competition with native forb communities. Additionally, conditions favoring increased invasive grass production in arid and semi-arid regions can increase fire risk, negatively impacting woody vegetation that is not adapted to fire. We conducted a seeded garden experiment and a 5-year field fertilization experiment to investigate how winter annual production is altered by increasing N supply under a range of water availabilities. The greatest production of invasive grasses and native forbs in the garden experiment occurred under the highest soil N (inorganic N after fertilization = 2.99 g m(-2)) and highest watering regime, indicating these species are limited by both water and N. A classification and regression tree (CART) analysis on the multi-year field fertilization study showed that winter annual biomass was primarily limited by November-December precipitation. Biomass exceeded the threshold capable of carrying fire when inorganic soil N availability was at least 3.2 g m(-2) in piñon-juniper woodland. Due to water limitation in creosote bush scrub, biomass exceeded the fire threshold only under very wet conditions regardless of soil N status. The CART analyses also revealed that percent cover of invasive grasses and native forbs is primarily dependent on the timing and amount of precipitation and secondarily dependent on soil N and site-specific characteristics. In total, our results indicate that areas of high N deposition will be susceptible to grass invasion, particularly in wet years, potentially reducing native species cover and increasing the risk of fire.

  11. Linking precipitation and C3-C4 plant production to resource dynamics in higher-trophic-level consumers.

    PubMed

    Warne, Robin W; Pershall, Alaina D; Wolf, Blair O

    2010-06-01

    In many ecosystems, seasonal shifts in temperature and precipitation induce pulses of primary productivity that vary in phenology, abundance, and nutritional quality. Variation in these resource pulses could strongly influence community composition and ecosystem function, because these pervasive bottom-up forces play a primary role in determining the biomass, life cycles, and interactions of organisms across trophic levels. The focus of this research is to understand how consumers across trophic levels alter resource use and assimilation over seasonal and interannual timescales in response to climatically driven changes in pulses of primary productivity. We measured the carbon isotope ratios (delta(13)C) of plant, arthropod, and lizard tissues in the northern Chihuahuan Desert to quantify the relative importance of primary production from plants using C3 and C4 photosynthesis for consumers. Summer monsoonal rains on the Sevilleta Long Term Ecological Research (LTER) site in New Mexico support a pulse of C4 plant production that has tissue delta(13)C values distinct from C3 plants. During a year when precipitation patterns were relatively normal, delta(13)C measurements showed that consumers used and assimilated significantly more C4-derived carbon over the course of a summer, tracking the seasonal increase in abundance of C4 plants. In the following spring, after a failure in winter precipitation and the associated failure of spring C3 plant growth, consumers showed elevated assimilation of C4-derived carbon relative to a normal rainfall regime. These findings provide insight into how climate, pulsed resources, and temporal trophic dynamics may interact to shape semiarid grasslands such as the Chihuahuan Desert in the present and future.

  12. Production and characterization of poly(3-hydroxybutyrate) generated by Alcaligenes latus using lactose and whey after acid protein precipitation process.

    PubMed

    Berwig, Karina Hammel; Baldasso, Camila; Dettmer, Aline

    2016-10-01

    Whey after acid protein precipitation was used as substrate for PHB production in orbital shaker using Alcaligenes latus. Statistical analysis determined the most appropriate hydroxide for pH neutralization of whey after protein precipitation among NH4OH, KOH and NaOH 10%w/v. The results were compared to those of commercial lactose. A scale-up test in a 4L bioreactor was done at 35°C, 750rpm, 7L/min air flow, and 6.5 pH. The PHB was characterized through Fourier Transform Infrared Spectroscopy, thermogravimetry and differential scanning calorimetry. NH4OH provided the best results for productivity (p), 0.11g/L.h, and for polymer yield, (YP/S), 1.08g/g. The bioreactor experiment resulted in lower p and YP/S. PHB showed maximum degradation temperature (291°C), melting temperature (169°C), and chemical properties similar to those of standard PHB. The use of whey as a substrate for PHB production did not affect significantly the final product quality.

  13. The space shuttle Discovery atop NASA's modified 747 is captured over the Mojave Desert while being ferried from NASA Dryden to the Kennedy Space Center

    NASA Image and Video Library

    2005-08-19

    The space shuttle Discovery atop NASA's modified 747 is captured over the Mojave Desert while being ferried from NASA Dryden to the Kennedy Space Center. NASA's modified Boeing 747 Shuttle Carrier Aircraft with the Space Shuttle Discovery on top lifts off from Edwards Air Force Base to begin its ferry flight back to the Kennedy Space Center in Florida. The cross-country journey will take two days, with stops at several intermediate points for refueling. Space shuttle Discovery landed safely at NASA's Dryden Flight Research Center at Edwards Air Force Base in California at 5:11:22 a.m. PDT, August 9, 2005, following the very successful 14-day STS-114 return to flight mission. During their two weeks in space, Commander Eileen Collins and her six crewmates tested out new safety procedures and delivered supplies and equipment the International Space Station. Discovery spent two weeks in space, where the crew demonstrated new methods to inspect and repair the Shuttle in orbit. The crew also delivered supplies, outfitted and performed maintenance on the International Space Station. A number of these tasks were conducted during three spacewalks. In an unprecedented event, spacewalkers were called upon to remove protruding gap fillers from the heat shield on Discovery's underbelly. In other spacewalk activities, astronauts installed an external platform onto the Station's Quest Airlock and replaced one of the orbital outpost's Control Moment Gyroscopes. Inside the Station, the STS-114 crew conducted joint operations with the Expedition 11 crew. They unloaded fresh supplies from the Shuttle and the Raffaello Multi-Purpose Logistics Module. Before Discovery undocked, the crews filled Raffeallo with unneeded items and returned to Shuttle payload bay. Discovery launched on July 26 and spent almost 14 days on orbit.

  14. Global Assessment of Dryland Degradation Using Long-Term Earth Observation Data Sets of Precipitation and Vegetation Productivity

    NASA Astrophysics Data System (ADS)

    Horion, S.; Fensholt, R.; Verbesselt, J.; Tagesson, T.; Rasmussen, K.

    2013-12-01

    Continuous time series of high quality Earth Observation (EO) based estimates of vegetation are key information for the assessment of long-term degradation in ecosystem function and productivity. In arid and semi-arid areas it has been reported that land degradation (LD) affects the well-being of 250 million people worldwide, which places it among today's most pressing environmental issues. However scientifically robust methods for assessing land degradation at global scale are still lacking. Indeed LD processes are complex and driven by multiple factors, either natural (e.g. changes in climate variability) or anthropic (eg. over-/mis- use of land resources), those factors often being region dependent. Traditionally LD assessment methods are based on the postulate that water availability is the major climate determinant for plant growth and production in drylands. Relationships between precipitation and above-ground net primary productivity (ANPP) have been extensively studied to better understand the impact of climate variability on dryland vegetation productivity. Besides it has been claimed that the ratio ANPP to precipitation, known as the Rain-Use Efficiency (RUE), is a conservative property of the vegetation cover in drylands if the vegetation cover is not subject to non-precipitation related LD; and therefore change in RUE could inform on human-induced degradation. However several authors have put forward the many limitations of RUE and gave recommendations for a proper use of this concept (e.g. Fensholt et al. 2013, Prince et al. 2007). Fensholt et al. (2013) notably recommend to restrict its use to areas where a linear relationship between rainfall and the selected EO based proxy for ANPP is found and where the regression offset of this relationship is close to zero. In this study the concept of RUE as indicator of human-induced LD in drylands will be evaluated at global scale. Both long-term trends and abrupt changes in RUE time series will be analyzed

  15. Regional Consistency of Global Precipitation Products and their Interactions with Soil Moisture and Water Storage over the Arabian Peninsula

    NASA Astrophysics Data System (ADS)

    Wehbe, Y. R.; Temimi, M.; Ghebreyesus, D. T.; Milewski, A.

    2016-12-01

    Numerous global precipitation products have been recently developed, but their spatio-temporal agreement over arid regions remains questionable. The goal of this study was (i) to assess the regional consistency of four distinct precipitation products from the Global Precipitation Climate Center (GPCC), Tropical Rainfall Measuring Mission (TRMM), Willmott-Matsuura dataset (WM), and the NOAH Climate Prediction Center Morphing Technique (CMORPH) and (ii) to inter-compare their macroscale impact on the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) soil moisture and Gravity Recovery and Climate Experiment (GRACE) water storage datasets over the Arabian Peninsula. The consistency of precipitation products was studied locally by spatial averages using the ANOVA test and extended spatially with a pair-wise student's t-test for difference in means. Next, Pearson correlation metrics were used to infer the correlation structure of the diverse components of the Peninsula's water cycle. ANOVA test results showed that the TRMM, GPCC, and WM datasets have insignificant mean difference during wet seasons, while only GPCC and TRMM datasets have insignificant mean difference during dry seasons. CMORPH was found to persistently underestimate rainfall quantities during both seasons. The spatial t-test corroborated the findings with the GPCC-TRMM comparison recording insignificant mean difference over more than 90% of the Peninsula. Any pairing with the CMORPH product gave significant mean difference over more than 90% of the Peninsula. The highest significant correlations, reaching 0.94 between GPCC-TRMM further supported the findings. Peak correlations with the AMSR-E soil moisture readings were recorded over the central and northwestern regions of the peninsula, while much lower correlations were consistently recorded over the southern part. When compared to GRACE anomalies, the examined products were assessed locally over the UAE using in situ wells

  16. Comparison of products from ERA-40, NCEP-2, and CRU with station data for summer precipitation over China

    NASA Astrophysics Data System (ADS)

    Zhao, T. B.; Fu, C. B.

    2006-07-01

    Summer precipitation products from the 45-Year European Centre for Weather Forecast (ECTMWF) Reanalysis (ERA-40), and NCEP-Department of Energy (DOE) Atmospheric Model Intercomparison Project (ATMIP-II) Reanalysis (NCEP-2), and Climatic Research Unit (CRU) TS 2.1 dataset are compared with the corresponding observations over China in order to understand the quality, and utility of the reanalysis datasets for the period 1979-2001. The results reveal that although the magnitude and location of the rainfall belts differ among the reanalysis, CRU, and station data over South and West China, the spatial distributions show good agreement over most areas of China. In comparison with the observations in most areas of China, CRU best matches the observed summer precipitation, while ERA-40 reports less precipitation and NCEP-2 reports more precipitation than the observations. With regard to the amplitude of the interannual variations, CRU is better than either of the reanalyses in representing the corresponding observations. The amplitude in NCEP-2 is stronger but that of ERA-40 is weaker than the observations in most study domains. NCEP-2 has a more obvious interannual variability than ERA-40 or CRU in most areas of East China. Through an Empirical orthogonal function (EOF) analysis, the main features of the rainfall belts produced by CRU aggree better with the observations than with those produced by the reanalyses in the Yangtze-Huaihe River valley. In East of China, particularly in the Yangtze-Huaihe River valley, CRU can reveal the quasi-biennial oscillation of summer precipitation represented by the observations, but the signal of ERA-40 is comparatively weak and not very obvious, whereas that of NCEP-2 is also weak before 1990 but very strong after 1990. The results also suggest that the magnitude of the precipitation difference between ERA-40 and the observations is smaller than that between NCEP-2 and the observations, but the variations represented by NCEP-2 are

  17. Precipitation and Carbon-Water Coupling Jointly Control the Interannual Variability of Global Land Gross Primary Production

    NASA Technical Reports Server (NTRS)

    Zhang, Yao; Xiao, Xiangming; Guanter, Luis; Zhou, Sha; Ciais, Philippe; Joiner, Joanna; Sitch, Stephen; Wu, Xiaocui; Nabel, Julian; Dong, Jinwei; Kato, Etsushi; Jain, Atul K.; Wiltshire, Andy; Stocker, Benjamin D.

    2016-01-01

    Carbon uptake by terrestrial ecosystems is increasing along with the rising of atmospheric CO2 concentration. Embedded in this trend, recent studies suggested that the interannual variability (IAV) of global carbon fluxes may be dominated by semi-arid ecosystems, but the underlying mechanisms of this high variability in these specific regions are not well known. Here we derive an ensemble of gross primary production (GPP) estimates using the average of three data-driven models and eleven process-based models. These models are weighted by their spatial representativeness of the satellite-based solar-induced chlorophyll fluorescence (SIF). We then use this weighted GPP ensemble to investigate the GPP variability for different aridity regimes. We show that semi-arid regions contribute to 57% of the detrended IAV of global GPP. Moreover, in regions with higher GPP variability, GPP fluctuations are mostly controlled by precipitation and strongly coupled with evapotranspiration (ET). This higher GPP IAV in semi-arid regions is co-limited by supply (precipitation)-induced ET variability and GPP-ET coupling strength. Our results demonstrate the importance of semi-arid regions to the global terrestrial carbon cycle and posit that there will be larger GPP and ET variations in the future with changes in precipitation patterns and dryland expansion.

  18. Precipitation and Carbon-Water Coupling Jointly Control the Interannual Variability of Global Land Gross Primary Production

    NASA Technical Reports Server (NTRS)

    Zhang, Yao; Xiao, Xiangming; Guanter, Luis; Zhou, Sha; Ciais, Philippe; Joiner, Joanna; Sitch, Stephen; Wu, Xiaocui; Nabel, Julian; Dong, Jinwei; hide

    2016-01-01

    Carbon uptake by terrestrial ecosystems is increasing along with the rising of atmospheric CO2 concentration. Embedded in this trend, recent studies suggested that the interannual variability (IAV) of global carbon fluxes may be dominated by semi-arid ecosystems, but the underlying mechanisms of this high variability in these specific regions are not well known. Here we derive an ensemble of gross primary production (GPP) estimates using the average of three data-driven models and eleven process-based models. These models are weighted by their spatial representativeness of the satellite-based solar-induced chlorophyll fluorescence (SIF). We then use this weighted GPP ensemble to investigate the GPP variability for different aridity regimes. We show that semi-arid regions contribute to 57% of the detrended IAV of global GPP. Moreover, in regions with higher GPP variability, GPP fluctuations are mostly controlled by precipitation and strongly coupled with evapotranspiration (ET). This higher GPP IAV in semi-arid regions is co-limited by supply (precipitation)-induced ET variability and GPP-ET coupling strength. Our results demonstrate the importance of semi-arid regions to the global terrestrial carbon cycle and posit that there will be larger GPP and ET variations in the future with changes in precipitation patterns and dryland expansion.

  19. Precipitation and carbon-water coupling jointly control the interannual variability of global land gross primary production

    PubMed Central

    Zhang, Yao; Xiao, Xiangming; Guanter, Luis; Zhou, Sha; Ciais, Philippe; Joiner, Joanna; Sitch, Stephen; Wu, Xiaocui; Nabel, Julia; Dong, Jinwei; Kato, Etsushi; Jain, Atul K.; Wiltshire, Andy; Stocker, Benjamin D.

    2016-01-01

    Carbon uptake by terrestrial ecosystems is increasing along with the rising of atmospheric CO2 concentration. Embedded in this trend, recent studies suggested that the interannual variability (IAV) of global carbon fluxes may be dominated by semi-arid ecosystems, but the underlying mechanisms of this high variability in these specific regions are not well known. Here we derive an ensemble of gross primary production (GPP) estimates using the average of three data-driven models and eleven process-based models. These models are weighted by their spatial representativeness of the satellite-based solar-induced chlorophyll fluorescence (SIF). We then use this weighted GPP ensemble to investigate the GPP variability for different aridity regimes. We show that semi-arid regions contribute to 57% of the detrended IAV of global GPP. Moreover, in regions with higher GPP variability, GPP fluctuations are mostly controlled by precipitation and strongly coupled with evapotranspiration (ET). This higher GPP IAV in semi-arid regions is co-limited by supply (precipitation)-induced ET variability and GPP-ET coupling strength. Our results demonstrate the importance of semi-arid regions to the global terrestrial carbon cycle and posit that there will be larger GPP and ET variations in the future with changes in precipitation patterns and dryland expansion. PMID:28008960

  20. Precipitation and carbon-water coupling jointly control the interannual variability of global land gross primary production

    NASA Astrophysics Data System (ADS)

    Zhang, Yao; Xiao, Xiangming; Guanter, Luis; Zhou, Sha; Ciais, Philippe; Joiner, Joanna; Sitch, Stephen; Wu, Xiaocui; Nabel, Julia; Dong, Jinwei; Kato, Etsushi; Jain, Atul K.; Wiltshire, Andy; Stocker, Benjamin D.

    2016-12-01

    Carbon uptake by terrestrial ecosystems is increasing along with the rising of atmospheric CO2 concentration. Embedded in this trend, recent studies suggested that the interannual variability (IAV) of global carbon fluxes may be dominated by semi-arid ecosystems, but the underlying mechanisms of this high variability in these specific regions are not well known. Here we derive an ensemble of gross primary production (GPP) estimates using the average of three data-driven models and eleven process-based models. These models are weighted by their spatial representativeness of the satellite-based solar-induced chlorophyll fluorescence (SIF). We then use this weighted GPP ensemble to investigate the GPP variability for different aridity regimes. We show that semi-arid regions contribute to 57% of the detrended IAV of global GPP. Moreover, in regions with higher GPP variability, GPP fluctuations are mostly controlled by precipitation and strongly coupled with evapotranspiration (ET). This higher GPP IAV in semi-arid regions is co-limited by supply (precipitation)-induced ET variability and GPP-ET coupling strength. Our results demonstrate the importance of semi-arid regions to the global terrestrial carbon cycle and posit that there will be larger GPP and ET variations in the future with changes in precipitation patterns and dryland expansion.

  1. Analysis of the Diurnal Cycle of Precipitation and its Relation to Cloud Radiative Forcing Using TRMM Products

    NASA Technical Reports Server (NTRS)

    Randall, David A.; Fowler, Laura D.; Lin, Xin

    1998-01-01

    In order to improve our understanding of the interactions between clouds, radiation, and the hydrological cycle simulated in the Colorado State University General Circulation Model (CSU GCM), we focused our research on the analysis of the diurnal cycle of precipitation, top-of-the-atmosphere and surface radiation budgets, and cloudiness using 10-year long Atmospheric Model Intercomparison Project (AMIP) simulations. Comparisons the simulated diurnal cycle were made against the diurnal cycle of Earth Radiation Budget Experiment (ERBE) radiation budget and International Satellite Cloud Climatology Project (ISCCP) cloud products. This report summarizes our major findings over the Amazon Basin.

  2. Effects of 4D-Var data assimilation using remote sensing precipitation products in a WRF over the complex Heihe River Basin

    NASA Astrophysics Data System (ADS)

    Pan, Xiaoduo; Li, Xin; Cheng, Guodong

    2017-04-01

    Traditionally, ground-based, in situ observations, remote sensing, and regional climate modeling, individually, cannot provide the high-quality precipitation data required for hydrological prediction, especially over complex terrain. Data assimilation techniques are often used to assimilate ground observations and remote sensing products into models for dynamic downscaling. In this study, the Weather Research and Forecasting (WRF) model was used to assimilate two satellite precipitation products (TRMM 3B42 and FY-2D) using the 4D-Var data assimilation method. The results show that the assimilation of remote sensing precipitation products can improve the initial WRF fields of humidity and temperature, thereby improving precipitation forecasting and decreasing the spin-up time. Hence, assimilating TRMM and FY-2D remote sensing precipitation products using WRF 4D-Var can be viewed as a positive step toward improving the accuracy and lead time of numerical weather prediction models, particularly for short-term weather forecasting. Future work is proposed to assimilate a suite of remote sensing data, e.g., the combination of precipitation and soil moisture data, into a WRF model to improve 7-8 day forecasts of precipitation and other atmospheric variables.

  3. Impact of parameter fluctuations on the performance of ethanol precipitation in production of Re Du Ning Injections, based on HPLC fingerprints and principal component analysis.

    PubMed

    Sun, Li-Qiong; Wang, Shu-Yao; Li, Yan-Jing; Wang, Yong-Xiang; Wang, Zhen-Zhong; Huang, Wen-Zhe; Wang, Yue-Sheng; Bi, Yu-An; Ding, Gang; Xiao, Wei

    2016-01-01

    The present study was designed to determine the relationships between the performance of ethanol precipitation and seven process parameters in the ethanol precipitation process of Re Du Ning Injections, including concentrate density, concentrate temperature, ethanol content, flow rate and stir rate in the addition of ethanol, precipitation time, and precipitation temperature. Under the experimental and simulated production conditions, a series of precipitated resultants were prepared by changing these variables one by one, and then examined by HPLC fingerprint analyses. Different from the traditional evaluation model based on single or a few constituents, the fingerprint data of every parameter fluctuation test was processed with Principal Component Analysis (PCA) to comprehensively assess the performance of ethanol precipitation. Our results showed that concentrate density, ethanol content, and precipitation time were the most important parameters that influence the recovery of active compounds in precipitation resultants. The present study would provide some reference for pharmaceutical scientists engaged in research on pharmaceutical process optimization and help pharmaceutical enterprises adapt a scientific and reasonable cost-effective approach to ensure the batch-to-batch quality consistency of the final products.

  4. No-wash ethanol precipitation of dye-labeled reaction products improves DNA sequencing reads.

    PubMed

    Fujikura, Kohei

    2015-01-01

    The advent of DNA sequencing has significantly accelerated molecular biology and clinical genetic testing. Despite recent increases in next-generation sequencing throughput, the most popular platform for DNA sequencing is still the multi-capillary DNA sequencer, which is ideally suited for small-scale sequencing projects and is highly accurate. However, the methods remain time-consuming and laborious. Here, I describe a modified ethylenediaminetetraacetic acid (EDTA) method that skips the washing step in ethanol precipitation. My improvements to standard methods save labor, time, and cost per run and increase the sequence reads by 5 to 10%. This modified method will provide immediate benefits to many researchers. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Aspergillus carbonarius polygalacturonases purified by integrated membrane process and affinity precipitation for apple juice production.

    PubMed

    Nakkeeran, Ekambaram; Umesh-Kumar, Sukumaran; Subramanian, Rangaswamy

    2011-02-01

    Aspergillus carbonarius, when grown by submerged and solid-state fermentation, produces different molecular forms of polygalacturonase (PG; EC 3.2.1.15), among them a 42 kDa PG with a high specific activity of 7000 U/mg protein. When the enzymes were purified by integrated membrane process (IMP) and alginate affinity precipitation (AAP), the two processes concentrated different forms of the enzyme. The AAP process selectively purified and concentrated the high active PG whereas the IMP yielded different PGs and also amylase and protease. Evaluation of the AAP enzyme preparations for apple juice preparation under conditions usually employed commercially demonstrated that the high activity PG did not result in good juice clarity. With IMP processed enzymes, juice yields and clarity were similar to that obtained with commercial PG from A. niger.

  6. Production and Precipitation Hardening of Mg-Ca-Zn-Co Alloy for Tissue Engineering.

    PubMed

    Mutlu, Ilven

    2017-02-01

    In this study, Mg-Ca-Zn-Co alloy specimens for biomedical applications were produced by the powder metallurgy method. The Mg-Ca-Zn-Co alloy could be used as a scaffold material in tissue engineering applications. Electrochemical corrosion behavior of the specimens was investigated in simulated body fluid environment. Electrochemical corrosion resistance of the specimens was increased with increasing Zn and Ca contents of the alloy up to an optimum composition and then decreased. Optimum values for Ca and Zn additions were about 0.7 wt.% and 3.0 wt.% respectively. Young's modulus values of the specimens were determined by nondestructive ultrasonic measurement. Alloying element addition increased the Young's modulus of the specimens. Precipitation hardening of the Mg-Ca-Zn-Co alloy increased the Young's modulus and the corrosion rate of the specimens.

  7. Production of salbutamol sulfate for inhalation by high-gravity controlled antisolvent precipitation.

    PubMed

    Chiou, Herbert; Li, Li; Hu, Tingting; Chan, Hak-Kim; Chen, Jian-Feng; Yun, Jimmy

    2007-02-22

    The purpose of this study was to produce salbutamol sulfate (SS) as a model anti-asthmatic drug using high-gravity controlled precipitation (HGCP) through antisolvent crystallisation. An aqueous solution of SS was passed through a HGCP reactor with isopropanol as antisolvent to induce precipitation. Spray drying was employed to obtain dry powders. Scanning electron microscopy, X-ray powder diffraction (XRD), density measurement, thermal gravimetric analysis, and dynamic vapour sorption were carried out to characterise the powder physical properties. The aerosol performance of the powders was measured using an Aeroliser connected to a multiple stage liquid impinger operating at 60 L/min. The HGCP SS particles were elongated with 0.1 microm in width but varying length of several mum, which formed spherical agglomerates when spray dried. The particles showed the same XRD pattern and true density (1.3g/cm3) as the raw material, indicating that they belonged to the same crystalline form. However, the spray dried agglomerates had a much lower tapped density (0.1g/cm3) than the raw material (0.6g/cm3). Compared with the powder obtained by spray drying directly from an aqueous solution, the SS powders obtained from HGCP were much less hygroscopic (0.6% versus 10% water uptake at 90% RH). The in vitro aerosol performance showed a fine particle fraction FPFloaded and FPFemitted up to 54.5+/-4.9% and 71.3+/-10.0%, respectively. In conclusion, SS powder with suitable physical and aerosol properties can be obtained through antisolvent HGCP followed by spray drying.

  8. PRODUCTION OF PLUTONIUM FLUORIDE FROM BISMUTH PHOSPHATE PRECIPITATE CONTAINING PLUTONIUM VALUES

    DOEpatents

    Brown, H.S.; Bohlmann, E.G.

    1961-05-01

    A process is given for separating plutonium from fission products present on a bismuth phosphate carrier. The dried carrier is first treated with hydrogen fluoride at between 500 and 600 deg C whereby some fission product fluorides volatilize away from plutonium tetrafluoride, and nonvolatile fission product fluorides are formed then with anhydrous fluorine at between 400 and 500 deg C. Bismuth and plutonium distill in the form of volatile fluorides away from the nonvolatile fission product fluorides. The bismuth and plutonium fluorides are condensed at below 290 deg C.

  9. 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

  10. Comprehensive evaluation of multi-satellite precipitation products with a dense rain gauge network and optimally merging their simulated hydrological flows using the Bayesian model averaging method

    NASA Astrophysics Data System (ADS)

    Jiang, Shanhu; Ren, Liliang; Hong, Yang; Yong, Bin; Yang, Xiaoli; Yuan, Fei; Ma, Mingwei

    2012-07-01

    SummaryThis study first focuses on comprehensive evaluating three widely used satellite precipitation products (TMPA 3B42V6, TMPA 3B42RT, and CMORPH) with a dense rain gauge network in the Mishui basin (9972 km2) in South China and then optimally merge their simulated hydrologic flows with the semi-distributed Xinanjiang model using the Bayesian model averaging method. The initial satellite precipitation data comparisons show that the reanalyzed 3B42V6, with a bias of -4.54%, matched best with the rain gauge observations, while the two near real-time satellite datasets (3B42RT and CMORPH) largely underestimated precipitation by 42.72% and 40.81% respectively. With the model parameters first benchmarked by the rain gauge data, the behavior of the streamflow simulation from the 3B42V6 was also the most optimal amongst the three products, while the two near real-time satellite datasets produced deteriorated biases and Nash-Sutcliffe coefficients (NSCEs). Still, when the model parameters were recalibrated by each individual satellite data, the performance of the streamflow simulations from the two near real-time satellite products were significantly improved, thus demonstrating the need for specific calibrations of the hydrological models for the near real-time satellite inputs. Moreover, when optimally merged with respect to the streamflows forced by the two near real-time satellite precipitation products and all the three satellite precipitation products using the Bayesian model averaging method, the resulted streamflow series further improved and became more robust. In summary, the three current state-of-the-art satellite precipitation products have demonstrated potential in hydrological research and applications. The benchmarking, recalibration, and optimal merging schemes for streamflow simulation at a basin scale described in the present work will hopefully be a reference for future utilizations of satellite precipitation products in global and regional

  11. Urine Bacterial Community Convergence through Fertilizer Production: Storage, Pasteurization, and Struvite Precipitation.

    PubMed

    Lahr, Rebecca H; Goetsch, Heather E; Haig, Sarah J; Noe-Hays, Abraham; Love, Nancy G; Aga, Diana S; Bott, Charles B; Foxman, Betsy; Jimenez, Jose; Luo, Ting; Nace, Kim; Ramadugu, Kirtana; Wigginton, Krista R

    2016-11-01

    Source-separated human urine was collected from six public events to study the impact of urine processing and storage on bacterial community composition and viability. Illumina 16S rRNA gene sequencing revealed a complex community of bacteria in fresh urine that differed across collection events. Despite the harsh chemical conditions of stored urine (pH > 9 and total ammonia nitrogen > 4000 mg N/L), bacteria consistently grew to 5 ± 2 × 10(8) cells/mL. Storing hydrolyzed urine for any amount of time significantly reduced the number of operational taxonomic units (OTUs) to 130 ± 70, increased Pielou evenness to 0.60 ± 0.06, and produced communities dominated by Clostridiales and Lactobacillales. After 80 days of storage, all six urine samples from different starting materials converged to these characteristics. Urine pasteurization or struvite precipitation did not change the microbial community, even when pasteurized urine was stored for an additional 70 days. Pasteurization decreased metabolic activity by 50 ± 10% and additional storage after pasteurization did not lead to recovery of metabolic activity. Urine-derived fertilizers consistently contained 16S rRNA genes belonging to Tissierella, Erysipelothrix, Atopostipes, Bacteroides, and many Clostridiales OTUs; additional experiments must determine whether pathogenic species are present, responsible for observed metabolic activity, or regrow when applied.

  12. Design of a continuous process setup for precipitated calcium carbonate production from steel converter slag.

    PubMed

    Mattila, Hannu-Petteri; Zevenhoven, Ron

    2014-03-01

    A mineral carbonation process "slag2PCC" for carbon capture, utilization, and storage is discussed. Ca is extracted from steel slag by an ammonium salt solvent and carbonated with gaseous CO2 after the separation of the residual slag. The solvent is reused after regeneration. The effects of slag properties such as the content of free lime, fractions of Ca, Si, Fe, and V, particle size, and slag storage on the Ca extraction efficiency are studied. Small particles with a high free-lime content and minor fractions of Si and V are the most suitable. To limit the amount of impurities in the process, the slag-to-liquid ratio should remain below a certain value, which depends on the slag composition. Also, the design of a continuous test setup (total volume ∼75 L) is described, which enables quick process variations needed to adapt the system to the varying slag quality. Different precipitated calcium carbonate crystals (calcite and vaterite) are generated in different parts of the setup.

  13. Evaluation of feed COD/sulfate ratio as a control criterion for the biological hydrogen sulfide production and lead precipitation.

    PubMed

    Velasco, Antonio; Ramírez, Martha; Volke-Sepúlveda, Tania; González-Sánchez, Armando; Revah, Sergio

    2008-03-01

    The ability of sulfate-reducing bacteria to produce hydrogen sulfide and the high affinity of sulfide to react with divalent metallic cations represent an excellent option to remove heavy metals from wastewater. Different parameters have been proposed to control the hydrogen sulfide production by anaerobic bacteria, such as the organic and sulfate loading rates and the feed COD/SO4(2-) ratio. This work relates the feed COD/SO4(2-) ratio with the hydrogen sulfide production and dissolved lead precipitation, using ethanol as carbon and energy source in an up-flow anaerobic sludge blanket reactor. A maximum dissolved sulfide concentration of 470+/-7 mg S/L was obtained at a feed COD/SO4(2-) ratio of 2.5, with sulfate and ethanol conversions of approximately 94 and 87%, respectively. The lowest dissolved sulfide concentration (145+/-10 mg S/L) was observed with a feed COD/SO4(2-) ratio of 0.67. Substantial amounts of acetate (510-1730 mg/L) were produced and accumulated in the bioreactor from ethanol oxidation. Although only incomplete oxidation of ethanol to acetate was observed, the consortium was able to remove 99% of the dissolved lead (200 mg/L) with a feed COD/SO4(2-) ratio of 1.5. It was found that the feed COD/SO4(2-) ratio could be an adequate parameter to control the hydrogen sulfide production and the consequent precipitation of dissolved lead.

  14. A hybrid Bayesian-SVD based method to detect false alarms in PERSIANN precipitation estimation product using related physical parameters

    NASA Astrophysics Data System (ADS)

    Ghajarnia, Navid; Arasteh, Peyman D.; Araghinejad, Shahab; Liaghat, Majid A.

    2016-07-01

    Incorrect estimation of rainfall occurrence, so called False Alarm (FA) is one of the major sources of bias error of satellite based precipitation estimation products and may even cause lots of problems during the bias reduction and calibration processes. In this paper, a hybrid statistical method is introduced to detect FA events of PERSIANN dataset over Urmia Lake basin in northwest of Iran. The main FA detection model is based on Bayesian theorem at which four predictor parameters including PERSIANN rainfall estimations, brightness temperature (Tb), precipitable water (PW) and near surface air temperature (Tair) is considered as its input dataset. In order to decrease the dimensions of input dataset by summarizing their most important modes of variability and correlations to the reference dataset, a technique named singular value decomposition (SVD) is used. The application of Bayesian-SVD method in FA detection of Urmia Lake basin resulted in a trade-off between FA detection and Hit events loss. The results show success of proposed method in detecting about 30% of FA events in return for loss of about 12% of Hit events while better capability of this method in cold seasons is observed.

  15. A novel high-pressure precipitation tandem homogenization technology for drug nanocrystals production - a case study with ursodeoxycholic acid.

    PubMed

    Li, Yu; Wang, Yong; Yue, Peng-Fei; Hu, Peng-Yi; Wu, Zhen-Feng; Yang, Ming; Yuan, Hai-Long

    2014-09-01

    To overcome the limitations of the conventional particle size reduction technologies, a novel combinative particle size reduction method for the effective production of homogeneous nanosuspensions was investigated. Ursodeoxycholic acid, a poorly soluble drug representative, was tried to prepare nanosuspension by homogenization technology and high-pressure precipitation tandem homogenization technology. It was shown that the combinative approach could significantly improve the particle size reduction effectiveness over conventional homogenization approach. The Box-Behnken design analysis for process optimization revealed that the acceptable UDCA-NS was obtained wherein the optimal values of A, B, C and D were 10%, 500 bar, 0.125 and 600 bar, respectively. SEM results demonstrated that no significant aggregation or crystals growth could be observed in the freeze-dried UDCA nanocrystals. The DSC and XRD results showed that UDCA remained in a crystalline state. Dissolution velocities of the freeze-dried UDCA-NS powder were distinctly superior compared to those of the crude powder and physical mixture. The high-pressure precipitation tandem homogenization technology can be a good choice for nanosuspension preparation of poorly soluble UDCA, due to high efficiency of particle size reduction.

  16. Investigating the Role of Tropical Cyclone Precipitation in the Gross Primary Productivity of the Southeast US using an Ecohydrological Model

    NASA Astrophysics Data System (ADS)

    Brun, J.; Barros, A. P.

    2012-12-01

    A Land surface Eco-Hydrological Model (LEHM), combining water and energy budgets with photosynthesis activity, is used to estimate Gross Primary Production (GPP) over the SE US using NCEP Stage IV as precipitation forcing, NLDAS/NARR for the atmospheric forcing and MODIS LAI/FPAR for phenology representation. First, an evaluation against AmeriFlux and MODIS GPP data over the SE United States in order to establish the model's ability to capture vegetation dynamics for the different biomes of the SE US over several years depending on data availability. Second, a suite of numerical experiments is conducted to evaluate the impact of Tropical Cyclones (TCs) precipitation over the SE US. The numerical experiments consist of with and without simulations by replacing the signature of TC forcing by NARR-derived climatology of atmospheric forcing ahead of landfall during the TC terrestrial path. By comparing these GPP estimates with those obtained with the normal forcing, the areas of discrepancies where the GPP was significantly modulated by TC activity will be determined with a focus on the series of TCs in the 2004 and 2005 hurricane seasons. Finally, the interannual variability of the impact of hurricane activity on the carbon cycle of the SE US in the MODIS era will be evaluated.

  17. Online Tools for Uncovering Data Quality (DQ) Issues in Satellite-Based Global Precipitation Products

    NASA Technical Reports Server (NTRS)

    Liu, Zhong; Heo, Gil

    2015-01-01

    Data quality (DQ) has many attributes or facets (i.e., errors, biases, systematic differences, uncertainties, benchmark, false trends, false alarm ratio, etc.)Sources can be complicated (measurements, environmental conditions, surface types, algorithms, etc.) and difficult to be identified especially for multi-sensor and multi-satellite products with bias correction (TMPA, IMERG, etc.) How to obtain DQ info fast and easily, especially quantified info in ROI Existing parameters (random error), literature, DIY, etc.How to apply the knowledge in research and applications.Here, we focus on online systems for integration of products and parameters, visualization and analysis as well as investigation and extraction of DQ information.

  18. Accuracy and application of quantitative X-ray diffraction on the precipitation of struvite product.

    PubMed

    Lu, Xingwen; Shih, Kaimin; Li, Xiao-yan; Liu, Guoqiang; Zeng, Eddy Y; Wang, Fei

    2016-03-01

    Struvite (MgNH4PO4·6H2O) crystallization from wastewater can gain a great advantage for phosphorus recovery and recycling. Although the recovery process and reaction modeling have been investigated, few studies have been conducted to quantify the different phases in recovered phosphorus products. The quantitative X-ray diffraction (QXRD) technique was employed in the present study to quantitatively determine the crystal phases and amorphous content of recovered struvite-containing products. Substantial mixed phase samples (i.e. struvite, newberyite and amorphous phase) were prepared to perform quantitative analysis to calibrate against known phase composition information by Rietveld refinement on powder X-ray diffraction data. The results showed a high level of accuracy (mean error = ∼3%) in our quantification model and validated the use of the Rietveld method to quantify the amorphous and crystal phases in the struvite-containing products. In addition, the influence of N:P molar ratio on struvite crystallization suggested that the weight percentage of struvite increased from 52% to 93%, when the N:P molar ratio was elevated from 0.2:1 to 1.2:1. This finding suggested the effectiveness of QXRD in facilitating the recovery of quality struvite products from waste streams. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Extracellular matrix production and calcium carbonate precipitation by coral cells in vitro

    PubMed Central

    Helman, Yael; Natale, Frank; Sherrell, Robert M.; LaVigne, Michèle; Starovoytov, Valentin; Gorbunov, Maxim Y.; Falkowski, Paul G.

    2008-01-01

    The evolution of multicellularity in animals required the production of extracellular matrices that serve to spatially organize cells according to function. In corals, three matrices are involved in spatial organization: (i) an organic ECM, which facilitates cell–cell and cell–substrate adhesion; (ii) a skeletal organic matrix (SOM), which facilitates controlled deposition of a calcium carbonate skeleton; and (iii) the calcium carbonate skeleton itself, which provides the structural support for the 3D organization of coral colonies. In this report, we examine the production of these three matrices by using an in vitro culturing system for coral cells. In this system, which significantly facilitates studies of coral cell physiology, we demonstrate in vitro excretion of ECM by primary (nondividing) tissue cultures of both soft (Xenia elongata) and hard (Montipora digitata) corals. There are structural differences between the ECM produced by X. elongata cell cultures and that of M. digitata, and ascorbic acid, a critical cofactor for proline hydroxylation, significantly increased the production of collagen in the ECM of the latter species. We further demonstrate in vitro production of SOM and extracellular mineralized particles in cell cultures of M. digitata. Inductively coupled plasma mass spectrometry analysis of Sr/Ca ratios revealed the particles to be aragonite. De novo calcification was confirmed by following the incorporation of 45Ca into acid labile macromolecules. Our results demonstrate the ability of isolated, differentiated coral cells to undergo fundamental processes required for multicellular organization. PMID:18162537

  20. Global Potential Net Prmary Production Predicted from Vegetation Class, Precipitation, and Temperature

    USDA-ARS?s Scientific Manuscript database

    Net Primary Production (NPP), the difference between CO2 fixed by photosynthesis and CO2 lost to autotrophic respiration, is one of the most important components of the carbon cycle. Our goal was to develop a simple regression model to estimate global NPP using climate and land cover data. Approxima...

  1. Global Net Primary Production Predicted from Vegetation Class, Precipitation, and Temperature.

    USDA-ARS?s Scientific Manuscript database

    Net Primary Production (NPP), the difference between CO2 fixed by photosynthesis and CO2 lost to autotrophic respiration, is one of the most important components of the carbon cycle. Our goal was to develop a simple regression model to estimate global NPP using climate and land cover data. Approxima...

  2. Preliminary response of primary production and community composition to precipitation variation in a temperate grassland

    USDA-ARS?s Scientific Manuscript database

    a) Background/Questions/Methods Grassland ecosystems are water-limited and show the highest interannual ANPP variability across biomes. Changes in annual amounts or seasonality of rainfall may interact with soil texture to impact grassland ecosystem functions including net primary productivity (NPP...

  3. Validation of satellite OPEMW precipitation product with ground-based weather radar and rain gauge networks

    NASA Astrophysics Data System (ADS)

    Cimini, D.; Romano, F.; Ricciardelli, E.; Di Paola, F.; Viggiano, M.; Marzano, F. S.; Colaiuda, V.; Picciotti, E.; Vulpiani, G.; Cuomo, V.

    2013-05-01

    The Precipitation Estimation at Microwave Frequencies (PEMW) algorithm was developed at the Institute of Methodologies for Environmental Analysis of the National Research Council of Italy (IMAA-CNR) for inferring surface rain intensity (sri) from satellite passive microwave observations in the range from 89 to 190 GHz. The operational version of PEMW (OPEMW) has been running continuously at IMAA-CNR for two years, producing sri estimates feeding an operational hydrological model for forecasting flood alerts. This paper presents the validation of OPEMW against simultaneous ground-based observations obtained by a network of 20 weather radars and a network of more than 3000 rain gauges distributed over the Italian peninsula and main islands. The validation effort uses a data set spanning a one-year period (July 2011-June 2012). The effort evaluates dichotomous and continuous scores for the assessment of rain detection and quantitative estimate, respectively, investigating both spatial and temporal features. The analysis demonstrates 98% accuracy in correctly identifying rainy and non-rainy areas, and it quantifies the increased ability (with respect to random chance) to detect rainy and non-rainy areas (0.42-0.45 Heidke skill score) or rainy areas only (0.27-0.29 equitable threat score). Performances are better than average during summer, fall, and spring, while worse than average in the winter season. The spatial-temporal analysis does not show seasonal dependence except for larger mean absolute difference over the Alps and northern Apennines during winter, attributable to residual effect of snow cover. A binned analysis in the 0-15 mm h-1 range suggests that OPEMW tends to slightly overestimate sri values below 6-7 mm h-1, and to underestimate sri above those values. Depending upon the ground reference (either rain gauges or weather radars), the mean difference is 0.8-2.8 mm h-1, with a standard deviation within 2.6-3.1 mm h-1 and correlation coefficient within 0

  4. Net primary productivity and rain-use efficiency as affected by warming, altered precipitation, and clipping in a mixed-grass prairie.

    PubMed

    Xu, Xia; Sherry, Rebecca A; Niu, Shuli; Li, Dejun; Luo, Yiqi

    2013-09-01

    Grassland productivity in response to climate change and land use is a global concern. In order to explore the effects of climate change and land use on net primary productivity (NPP), NPP partitioning [fBNPP , defined as the fraction of belowground NPP (BNPP) to NPP], and rain-use efficiency (RUE) of NPP, we conducted a field experiment with warming (+3 °C), altered precipitation (double and half), and annual clipping in a mixed-grass prairie in Oklahoma, USA since July, 2009. Across the years, warming significantly increased BNPP, fBNPP , and RUEBNPP by an average of 11.6%, 2.8%, and 6.6%, respectively. This indicates that BNPP was more sensitive to warming than aboveground NPP (ANPP) since warming did not change ANPP and RUEANPP much. Double precipitation stimulated ANPP, BNPP, and NPP but suppressed RUEANPP , RUEBNPP , and RUENPP while half precipitation decreased ANPP, BNPP, and NPP but increased RUEANPP , RUEBNPP , and RUENPP . Clipping interacted with altered precipitation in impacting RUEANPP , RUEBNPP , and RUENPP , suggesting land use could confound the effects of precipitation changes on ecosystem processes. Soil moisture was found to be a main factor in regulating variation in ANPP, BNPP, and NPP while soil temperature was the dominant factor influencing fBNPP . These findings suggest that BNPP is critical point to future research. Additionally, results from single-factor manipulative experiments should be treated with caution due to the non-additive interactive effects of warming with altered precipitation and land use (clipping).

  5. Acid precipitation effects on algal productivity and biomass in Adirondack Mountain lakes

    SciTech Connect

    Hendrey, G.R.

    1982-12-01

    Relationships between phytoplankton communities and lake acidity in three Adirondack Mountain lakes were studied at Woods Lake (pH ca. 4.9), Sagamore Lake (pH ca. 5.5), and Panther Lake (pH ca. 7.0). Species numbers decrease with increasing acidity. Patterns of increasing biomass and productivity in Woods Lake may be atypical of similar oligotrophic lakes in that they develop rather slowly to maxima six weeks after ice-out, instead of occurring very close to ice-out. Contributions of netplankton, nannoplankton and ultraplankton to productivity per m/sup 2/ show that the smaller plankton are relatively more important in the more acid lakes. This pattern could be determined by nutrient availability (lake acidification is suspected of leading to decreased availability of phosphorus). This was consistent with a hypothesis that microbial heterotrophic activity is reduced with increasing acidity, but the smaller phytoplankton may be more leaky at low pH. 11 references, 2 tables.

  6. Acid precipitation effects on algal productivity and biomass in Adirondack Lakes. Final completion report

    SciTech Connect

    Hendrey, G.R.

    1982-12-01

    Relationships between phytoplankton communities and lake acidity in three Adirondack Mountain Lakes were studied at Woods Lake, Sagamore Lake (pH ca. 5.5), and Panther Lake (pH ca. 7.0). Numbers of phytoplankton species observed were Woods 45, Sagamore 55, and Panther 85, conforming to observations at many other sites that species numbers decrease with increasing acidity. The smaller plankton are relatively more important in the more acid lakes, Woods > Sagamore > Panther. This pattern could be determined by nutrient availability (lake acidification is suspected of leading to decreased availability of phosphorus). The amount of 14C-labelled dissolved photosynthate (14C-DOM), as a percent of total productivity, is ordered Woods > Sagamore > Panther.

  7. Precipitation of liquid swine manure phosphates using magnesium smelting by-products.

    PubMed

    Parent, Gaétan; Bélanger, Gilles; Ziadi, Noura; Deland, Jean-Pierre; Laperrière, Jean

    2007-01-01

    Swine manure contains considerable amounts of total (P) and soluble phosphorus (PO(4)-P) which may increase the soil P content when applied in excess to crop requirements and, consequently, risk water eutrophication. The feasibility of using magnesium (Mg) from the by-product of electrolysis and foundries (BPEF) for the removal of P from liquid swine manure was studied by adding up to 3 g of Mg as BPEF per liter of nursery (NU) and grower-finisher (GF) swine manure in 25-L plastic buckets. Changes in P and other elements were monitored for up to 360 h. Small amounts of Mg as BPEF (0.5 and 1.0 g Mg L(-1) manure) reduced the total P concentration of the liquid fraction by 70 to 95% of both manure types with respect to the control treatment of mixed raw manure. A settling period of 8 h or more was necessary to significantly reduce the liquid fraction's total P concentration for both manure types. Reduction of PO(4)-P varied from 96 to 100% in the liquid fractions for both manure types, which along with natural settling, explains most of the total P reduction in that fraction. The addition of BPEF did not influence the N content of manure. The low P liquid fraction can be safely applied to saturated P soils whereas the high P solid fraction offers the opportunity of transporting manure to agricultural soils deficient in P. Since N is conserved, both liquid and solid fractions could be valuable fertilizer manure by-products.

  8. Characterization of condensed tannins purified from legume forages: chromophore production, protein precipitation, and inhibitory effects on cellulose digestion.

    PubMed

    McAllister, Tim A; Martinez, Tomas; Bae, Hee Dong; Muir, Alister D; Yanke, L Jay; Jones, Graham A

    2005-09-01

    To identify simple screening tools for selecting condensed tannin (CT)-containing forages as candidate sources for further study, CT were isolated from nine legumes, and their molecular weights (MW), chromophore production, capacity to precipitate bovine serum albumin (BSA) and Fraction 1 protein (Rubisco) isolated from alfalfa, and inhibition of filter paper digestion were compared. Sources were as follows: leaves of sericea lespedeza (Lespedeza cuneata Dum.-Cours.), crown vetch (Coronilla varia L.), and sainfoin (Onobrychis viciifolia Scop.); stems of hedysarum (Hedysarum alpinum L.); seeds of alfalfa (Medicago sativa L.); and whole plants of birdsfoot trefoil (Lotus corniculatus var. corniculatus L.) and three varieties of big trefoil (Lotus pedunculatus Cav.), viz., Lotus uliginosus Schkuhr, L. uliginosus var. glabriusculus, and L. uliginosus var. villosus. Molecular weights and sizes (degrees of polymerization) of the CT varied considerably within and among plant species. Average MW ranged from 3036 Da (crown vetch) to 7143 Da (lespedeza). All CT exhibited greater capacity (w/w basis) to bind alfalfa Rubisco than BSA. Relative astringencies (microg CT required to precipitate 1 mg protein) against BSA ranged from 262.5 for CT from lespedeza to 435.5 for CT from L. corniculatus, and against Rubisco, from 49.6 (sainfoin) to 108.2 (alfalfa seed). Including CT at 300 microg/ml in cultures of Fibrobacter succinogenes reduced digestion of cellulose filter paper by 19.8% (sainfoin) to 92.4% (crown vetch) and increased the specific activity of cell-associated endoglucanase. There were no correlations between inhibitory effects of CT on filter paper digestion and (1) chromophore formation during CT assay by butanol-HCl, vanillin-HCl, or H2SO4; (2) precipitation of BSA or alfalfa Rubisco; and (3) MW of CT. The most inhibitory CT for cellulose digestion included those with broad and with narrow MW distributions. Sainfoin was the most desirable source of CT, as it had the

  9. Evaluating the performance of real-time streamflow forecasting using multi-satellite precipitation products in the Upper Zambezi, Africa

    NASA Astrophysics Data System (ADS)

    Demaria, E. M.; Valdes, J. B.; Wi, S.; Serrat-Capdevila, A.; Valdés-Pineda, R.; Durcik, M.

    2016-12-01

    In under-instrumented basins around the world, accurate and timely forecasts of river streamflows have the potential of assisting water and natural resource managers in their management decisions. The Upper Zambezi river basin is the largest basin in southern Africa and its water resources are critical to sustainable economic growth and poverty reduction in eight riparian countries. We present a real-time streamflow forecast for the basin using a multi-model-multi-satellite approach that allows accounting for model and input uncertainties. Three distributed hydrologic models with different levels of complexity: VIC, HYMOD_DS, and HBV_DS are setup at a daily time step and a 0.25 degree spatial resolution for the basin. The hydrologic models are calibrated against daily observed streamflows at the Katima-Mulilo station using a Genetic Algorithm. Three real-time satellite products: Climate Prediction Center's morphing technique (CMORPH), Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN), and Tropical Rainfall Measuring Mission (TRMM-3B42RT) are bias-corrected with daily CHIRPS estimates. Uncertainty bounds for predicted flows are estimated with the Inverse Variance Weighting method. Because concentration times in the basin range from a few days to more than a week, we include the use of precipitation forecasts from the Global Forecasting System (GFS) to predict daily streamflows in the basin with a 10-days lead time. The skill of GFS-predicted streamflows is evaluated and the usefulness of the forecasts for short term water allocations is presented.

  10. Dominant plant taxa predict plant productivity responses to CO2 enrichment across precipitation and soil gradients

    SciTech Connect

    Fay, Philip A.; Newingham, Beth A.; Polley, H. Wayne; Morgan, Jack A.; LeCain, Daniel R.; Nowak, Robert S.; Smith, Stanley D.

    2015-03-30

    The Earth’s atmosphere will continue to be enriched with carbon dioxide (CO2) over the coming century. Carbon dioxide enrichment often reduces leaf transpiration, which in water-limited ecosystems may increase soil water content, change species abundances and increase the productivity of plant communities. The effect of increased soil water on community productivity and community change may be greater in ecosystems with lower precipitation, or on coarser-textured soils, but responses are likely absent in deserts. We tested correlations among yearly increases in soil water content, community change and community plant productivity responses to CO2 enrichment in experiments in a mesic grassland with fine- to coarse-textured soils, a semi-arid grassland and a xeric shrubland. We found no correlation between CO2-caused changes in soil water content and changes in biomass of dominant plant taxa or total community aboveground biomass in either grassland type or on any soil in the mesic grassland (P > 0.60). Instead, increases in dominant taxa biomass explained up to 85% of the increases in total community biomass under CO2 enrichment. The effect of community change on community productivity was stronger in the semi-arid grassland than in the mesic grassland,where community biomass change on one soil was not correlated with the change in either the soil water content or the dominant taxa. No sustained increases in soil water content or community productivity and no change in dominant plant taxa occurred in the xeric shrubland. Thus, community change was a crucial driver of community productivity responses to CO2 enrichment in the grasslands, but effects of soil water change on productivity were not evident in yearly responses to CO2 enrichment. In conclusion, future research is necessary to isolate and clarify the mechanisms controlling the temporal and spatial variations in the linkages among soil water

  11. A Validation Study of the NWS/MPE Precipitation Products Using a Dense Rain Gauge Network in South Louisiana

    NASA Astrophysics Data System (ADS)

    Larson, B. F.; Habib, E.; Graschel, J.; Nelson, B. R.

    2007-12-01

    This study focuses on validation of the multi-sensor precipitation products developed by the operational multi- sensor precipitation estimation (MPE) algorithm of the National Weather Service (NWS) River Forecast Centers (RFC). MPE data are acquired through the Stage IV archives at the National Center for Environmental Prediction (NCEP). MPE data, which is based upon the merging of data from WSR-88D radar, surface rain gauge, and occasionally geo-stationary satellite data, is provided at hourly temporal resolution and over a national Hydrologic Rainfall Analysis Project (HRAP) grid which has a nominal size of 4 square kilometers. Operational hydrologic forecasting applications now require higher spatial and temporal resolution which is provided by radar data. To help determine the validity of radar data in south Louisiana, a study was performed on MPE data for a three-year period (2004-2006) using 13 independently operated rain gauges located within an area of ~30 km2. The close proximity of gauge sites to each other allows for multiple gauges to be located within the same HRAP pixel. As a result, two pixels contained four gauges each, and one pixel contained two gauges. This co-location of multiple gauges within an HRAP pixel allows for a reasonably accurate estimation of the MPE errors over different scales such as hourly, daily, and monthly temporal resolution. In this context, the errors are defined as the deviation of MPE estimates from the corresponding average of gauge measurements in each pixel. The self dependence of these errors is assessed by analyzing their temporal and spatial auto-correlations. The MPE products are mainly intended for operational hydrologic forecasting. Therefore, the study will examine the impact of MPE uncertainties on runoff simulations in a mid-size experimental watershed in south Louisiana. The physically- based hydrologic model (Gridded Surface Subsurface Hydrologic Analysis, GSSHA) is driven by two sets of rainfall forcing: MPE

  12. Detection of chlorodifluoroacetic acid in precipitation: A possible product of fluorocarbon degradation

    SciTech Connect

    Martin, J.W.; Franklin, J.; Hanson, M.L.; Solomon, K.R.; Mabury, S.A.; Ellis, D.A.; Scott, B.F.; Muri, D.C.G.

    2000-01-15

    Chlorodiffluoroacetic acid (CDFA) was detected in rain and snow samples from various regions of Canada. Routine quantitative analysis was performed using an in-situ derivatization technique that allowed for the determination of CDFA by GC-MS of the anilide derivative. Validation of environmental CDFA was provided by strong anionic exchange chromatography and detection by {sup 19}F NMR. CDFA concentrations ranges from <7.1 to 170 ng L{sup {minus}1} among all samples analyzed. Monthly volume-weighted CDFA concentrations ranged from <7.1 to 170 ng L{sup {minus}1} among all samples analyzed. Monthly volume-weighted CDFA concentrations in rain event samples showed a seasonal trend between June and November 1998, peaking in late summer and decreasing in the fall for Guelph and Toronto sites. Preliminary toxicity tests with the aquatic macrophytes Myriophyllum sibiricum and Myriophyllum spicatum suggest that CDFA does not represent a risk of acute toxicity to these aquatic macrophytes at current environmental concentrations. A degradation study suggests that CDFA is recalcitrant to biotic and abiotic degradation relative to dichloroacetic acid (DCA) and may accumulate in the aquatic environment. On the basis of existing experimental data, the authors postulate that CDFA is a degradation product of CFC-113 and, to a lesser extent, HCFC-142b. If CFC-113 is a source, its ozone depletion potential may be lower than previously assumed. Further work is required to identify alternative atmospheric and terrestrial sources of CDFA.

  13. The utilization of waste by-products for removing silicate from mineral processing wastewater via chemical precipitation.

    PubMed

    Kang, Jianhua; Sun, Wei; Hu, Yuehua; Gao, Zhiyong; Liu, Runqing; Zhang, Qingpeng; Liu, Hang; Meng, Xiangsong

    2017-08-22

    This study investigates an environmentally friendly technology that utilizes waste by-products (waste acid and waste alkali liquids) to treat mineral processing wastewater. Chemical precipitation is used to remove silicate from scheelite (CaWO4) cleaning flotation wastewater and the waste by-products are used as a substitute for calcium chloride (CaCl2). A series of laboratory experiments is conducted to explain the removal of silicate and the characterization and formation mechanism of calcium silicate. The results show that silicate removal reaches 90% when the Ca:Si molar ratio exceeds 1.0. The X-ray diffraction (XRD) results confirm the characterization and formation of calcium silicate. The pH is the key factor for silicate removal, and the formation of polysilicic acid with a reduction of pH can effectively improve the silicate removal and reduce the usage of calcium. The economic analysis shows that the treatment costs with waste acid (0.63 $/m(3)) and waste alkali (1.54 $/m(3)) are lower than that of calcium chloride (2.38 $/m(3)). The efficient removal of silicate is confirmed by industrial testing at a plant. The results show that silicate removal reaches 85% in the recycled water from tailings dam. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Evaluation of the TMPA-3B42 precipitation product using a high-density rain gauge network over complex terrain in northeastern Iberia

    NASA Astrophysics Data System (ADS)

    El Kenawy, Ahmed M.; Lopez-Moreno, Juan I.; McCabe, Matthew F.; Vicente-Serrano, Sergio M.

    2015-10-01

    The performance of the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA)-3B42 version 7 product is assessed over north-eastern Iberia, a region with considerable topographical gradients and complexity. Precipitation characteristics from a dense network of 656 rain gauges, spanning the period from 1998 to 2009, are used to evaluate TMPA-3B42 estimates on a daily scale. A set of accuracy estimators, including the relative bias, mean absolute error (MAE), root mean square error (RMSE) and Spearman coefficient was used to evaluate the results. The assessment indicates that TMPA-3B42 product is capable of describing the seasonal characteristics of the observed precipitation over most of the study domain. In particular, TMPA-3B42 precipitation agrees well with in situ measurements, with MAE less than 2.5 mm.day- 1, RMSE of 6.4 mm.day- 1 and Spearman correlation coefficients generally above 0.6. TMPA-3B42 provides improved accuracies in winter and summer, whereas it performs much worse in spring and autumn. Spatially, the retrieval errors show a consistent trend, with a general overestimation in regions of low altitude and underestimation in regions of heterogeneous terrain. TMPA-3B42 generally performs well over inland areas, while showing less skill in the coastal regions. A set of skill metrics, including a false alarm ratio [FAR], frequency bias index [FBI], the probability of detection [POD] and threat score [TS], is also used to evaluate TMPA performance under different precipitation thresholds (1, 5, 10, 25 and 50 mm.day- 1). The results suggest that TMPA-3B42 retrievals perform well in specifying moderate rain events (5-25 mm.day- 1), but show noticeably less skill in producing both light (< 1 mm.day- 1) and heavy rainfall thresholds (more than 50 mm.day- 1). Given the complexity of the terrain and the associated high spatial variability of precipitation in north-eastern Iberia, the results reveal that TMPA-3B42 data provide

  15. Electrostatic Precipitator

    NASA Image and Video Library

    2017-06-09

    New Electrostatic Precipitator in a flow-through system. The precipitator system is being developed to remove dust from the atmospheric intakes of the MARS ISRU chambers. It uses electrostatic forces for the dust removal.

  16. Hydrological Evaluation of Satellite-Based Precipitation Products over the Volta and Baro-Akobo Basin

    NASA Astrophysics Data System (ADS)

    Thiemig, Vera; Zambrano, Mauricio; Rojas, Rodrigo; De Roo, Ad

    2013-04-01

    How useful are satellite-based rainfall estimates (SRFE) as forcing data for hydrological applications? Which SRFE should be favoured for hydrological modelling? What could researchers do to increase the performance of SRFE-driven hydrological simulations? To address these three research questions, four SRFE (CMORPH, RFE 2.0, TRMM-3B42 and PERSIANN) and one reanalysis product (ERA-Interim) are evaluated within a hydrological application for the time period 2003-2008, over two river basins (Volta and Baro-Akobo) which hold distinct physiographic, climatologic and hydrologic conditions. The focus was on the assessment of: a) the individual and combined effect of SRFE-specific calibration and bias-correction on the hydrological performance, b) the level of complexity required regarding bias-correction and interpolation to achieve a good hydrological performance, and c) the hydrological performance of SRFE during high- and low-flow conditions. Results show that 1) the hydrological performance is always higher if the model is calibrated to the respective SRFE rather than to interpolated ground observations; 2) for SRFE that are afflicted with bias, a bias-correction step prior to SRFE-specific calibration is essential, while for SRFE with good intrinsic data quality applying a SRFE-specific model calibration is sufficient; 3) the more sophisticated bias-correction method used in this work (histogram equalization) results generally in a superior hydrological performance, while a more sophisticated interpolation method (Kriging with External Drift) seems to be of added value only over mountainous regions; 4) the bias-correction is not over-proportionally important over mountainous catchments, as it solely depends on where the SRFE show high biases (e.g. for PERSIANN and CMORPH over lowland areas); and 5) the hydrological performance during high-flow conditions is superior thus promoting the use of SRFE for applications focusing on the high-end flow spectrum. These results

  17. Calcium carbonate precipitation by heterotrophic bacteria isolated from biofilms formed on deteriorated ignimbrite stones: influence of calcium on EPS production and biofilm formation by these isolates.

    PubMed

    López-Moreno, Angélica; Sepúlveda-Sánchez, José David; Mercedes Alonso Guzmán, Elia Mercedes; Le Borgne, Sylvie

    2014-01-01

    Heterotrophic CaCO3-precipitating bacteria were isolated from biofilms on deteriorated ignimbrites, siliceous acidic rocks, from Morelia Cathedral (Mexico) and identified as Enterobacter cancerogenus (22e), Bacillus sp. (32a) and Bacillus subtilis (52g). In solid medium, 22e and 32a precipitated calcite and vaterite while 52g produced calcite. Urease activity was detected in these isolates and CaCO3 precipitation increased in the presence of urea in the liquid medium. In the presence of calcium, EPS production decreased in 22e and 32a and increased in 52g. Under laboratory conditions, ignimbrite colonization by these isolates only occurred in the presence of calcium and no CaCO3 was precipitated. Calcium may therefore be important for biofilm formation on stones. The importance of the type of stone, here a siliceous stone, on biological colonization is emphasized. This calcium effect has not been reported on calcareous materials. The importance of the effect of calcium on EPS production and biofilm formation is discussed in relation to other applications of CaCO3 precipitation by bacteria.

  18. Effects of altered seasonality of precipitation on grass production and grasshopper performance in a northern mixed prairie

    USDA-ARS?s Scientific Manuscript database

    Climatic changes are leading to differing patterns and timing of precipitation in grassland ecosystems, with the seasonal timing of precipitation affecting plant biomass and plant composition. No previous studies have examined how drought seasonality affects grasshopper performance and the impact of...

  19. Influence of nonnative and native ungulate biomass and seasonal precipitation on vegetation production in a Great Basin ecosystem

    USGS Publications Warehouse

    Zeigenfuss, Linda C.; Schoenecker, Kathryn A.; Ransom, Jason I.; Ignizio, Drew A.; Mask, Tracy

    2014-01-01

    The negative effects of equid grazers in semiarid ecosystems of the American West have been considered disproportionate to the influence of native ungulates in these systems because of equids' large body size, hoof shape, and short history on the landscape relative to native ungulates. Tools that can analyze the degree of influence of various ungulate herbivores in an ecosystem and separate effects of ungulates from effects of other variables (climate, anthropomorphic disturbances) can be useful to managers in determining the location of nonnative herbivore impacts and assessing the effect of management actions targeted at different ungulate populations. We used remotely sensed data to determine the influence of native and nonnative ungulates and climate on vegetation productivity at wildlife refuges in Oregon and Nevada. Our findings indicate that ungulate biomass density, particularly equid biomass density, and precipitation in winter and spring had the greatest influence on normalized difference vegetation index (NDVI) values. Our results concur with those of other researchers, who found that drought exacerbated the impacts of ungulate herbivores in arid systems.

  20. Supplemental irrigation as an initiative to support water and food security: A global evaluation of the potential to support and increase precipitation-fed wheat production

    NASA Astrophysics Data System (ADS)

    Smilovic, M.; Gleeson, T. P.; Adamowski, J. F.; Langhorn, C.; Kienzle, S. W.

    2016-12-01

    Supplemental irrigation is the practice of supporting precipitation-fed agriculture with limited irrigation. Precipitation-fed agriculture dominates the agricultural landscape, but is vulnerable to intraseasonal and interannual variability in precipitation and climate. The interplay between food security, water resources, ecosystem health, energy, and livelihoods necessitates evaluating and integrating initiatives that increase agricultural production while reducing demands on water resources. Supplemental irrigation is the practice of minimally irrigating in an effort to stabilize and increase agricultural production, as well as increase water productivity - the amount of crop produced per unit of water. The potential of supplemental irrigation to support both water and food security has yet to be evaluated at regional and global scales. We evaluate whether supplemental irrigation could stabilize and increase agricultural production of wheat by determining locally-calibrated water use-crop yield relationships, known as crop-water production functions. Crop-water production functions are functions of seasonal water use and crop yield, and previous efforts have largely ignored the effects of the temporal distribution of water use throughout the growing season. We significantly improve upon these efforts and provide an opportunity to evaluate supplemental irrigation that appropriately acknowledges the effects of irrigation scheduling. Integrating agroclimatic and crop data with the crop-water model Aquacrop, we determine the increases in wheat production achieved by maximizing water productivity, sharing limited water between different years, and other irrigation scenarios. The methodology presented and evaluation of supplemental irrigation provides water mangers, policy makers, governments, and non-governmental organizations the tools to appropriately understand and determine the potential of this initiative to support precipitation-fed agriculture.

  1. Validation of a new SAFRAN-based gridded precipitation product for Spain and comparisons to Spain02 and ERA-Interim

    NASA Astrophysics Data System (ADS)

    Quintana-Seguí, Pere; Turco, Marco; Herrera, Sixto; Miguez-Macho, Gonzalo

    2017-04-01

    Offline land surface model (LSM) simulations are useful for studying the continental hydrological cycle. Because of the nonlinearities in the models, the results are very sensitive to the quality of the meteorological forcing; thus, high-quality gridded datasets of screen-level meteorological variables are needed. Precipitation datasets are particularly difficult to produce due to the inherent spatial and temporal heterogeneity of that variable. They do, however, have a large impact on the simulations, and it is thus necessary to carefully evaluate their quality in great detail. This paper reports the quality of two high-resolution precipitation datasets for Spain at the daily time scale: the new SAFRAN-based dataset and Spain02. SAFRAN is a meteorological analysis system that was designed to force LSMs and has recently been extended to the entirety of Spain for a long period of time (1979/1980-2013/2014). Spain02 is a daily precipitation dataset for Spain and was created mainly to validate regional climate models. In addition, ERA-Interim is included in the comparison to show the differences between local high-resolution and global low-resolution products. The study compares the different precipitation analyses with rain gauge data and assesses their temporal and spatial similarities to the observations. The validation of SAFRAN with independent data shows that this is a robust product. SAFRAN and Spain02 have very similar scores, although the latter slightly surpasses the former. The scores are robust with altitude and throughout the year, save perhaps in summer when a diminished skill is observed. As expected, SAFRAN and Spain02 perform better than ERA-Interim, which has difficulty capturing the effects of the relief on precipitation due to its low resolution. However, ERA-Interim reproduces spells remarkably well in contrast to the low skill shown by the high-resolution products. The high-resolution gridded products overestimate the number of precipitation days

  2. Amino acid, fatty acid, and mineral profiles of materials recovered from rainbow trout (Oncorhynchus mykiss) processing by-products using isoelectric solubilization/precipitation.

    PubMed

    Chen, Y-C; Tou, J C; Jaczynski, J

    2007-11-01

    Protein, lipid, and insolubles (bones, skin, scales, fins, insoluble protein, and more) were recovered from rainbow trout processing by-products by means of isoelectric solubilization/precipitation at basic pH and acidic pH. Isoelectric solubilization/precipitation of the trout processing by-products resulted in the recovery of protein that was higher (P < 0.05) in essential amino acids (EAAs), non-EAAs, and total EAA/total AA ratio when compared to the processing by-products. Basic pH treatments yielded a higher (P < 0.05) content of EAAs than the acidic pH treatments. Nutritional quality of the recovered protein was high based on EAAs meeting the FAO/WHO/UNU recommendations for adults. The presence of omega-3 and omega-6 fatty acids (omega-3, omega-6 FAs) and the omega-3/omega-6 ratio in the recovered lipids were similar to the trout processing by-products, indicating that the pH treatments had no effect on these FAs. Ca and P contents of the processing by-products exceeded the recommended dietary allowances (RDA), but Fe and Mg did not. Basic pH treatments yielded protein with the lowest (P < 0.05) amount of minerals and the highest (P < 0.05) amount of Ca, P, and Mg in the insolubles when compared to acidic pH. The isoelectric solubilization/precipitation of the processing by-products effectively removed minerals from the recovered protein without removal of the bones, skin, scales, fins, and so on, prior to processing. The results indicated that isoelectric solubilization/precipitation, particularly at basic pH, permitted recovery of high-quality protein and lipids from fish processing by-products for human food uses; also, the recovered insolubles may be used in animal feeds as a source of minerals.

  3. Electrostatic precipitation

    SciTech Connect

    Albanese, V.

    1980-07-22

    A method is described of improving the conductivity of particles entrained in a stream of particle-laden gas formed by the burning of coal. The particles are collected by an electrostatic precipitator which comprises treating said gas containing particles prior to contact with the electrostatic precipitator at a temperature not greater than about 800/sup 0/F with a resistivitydecreasing amount of hexamethylene tetramine or its water-soluble salts and thereafter passing the gas to the electrostatic precipitator.

  4. Comparison of versions 6 and 7 3-hourly TRMM multi-satellite precipitation analysis (TMPA) research products

    NASA Astrophysics Data System (ADS)

    Liu, Zhong

    2015-09-01

    This paper examines differences between Version 6 (V6) and Version 7 (V7) 3-hourly TRMM (Tropical Rainfall Measuring Mission) Multi-Satellite Precipitation Analysis (TMPA 3B42) research products in JJA (June, July and August) and DJF (December, January and February) over a 13-year period from 1998 to 2010 on a global scale. Different surface types and rain regimes are considered in the comparison. The study finds that more rain events are found in V7 than those in V6 in both JJA and DJF, especially over oceans. Overall, both versions show a good agreement in moderate and heavy rain regimes. High Pearson's correlation coefficients are found in tropical rain band regions. Histograms of both versions are very similar; however higher frequencies of rain events are found in V7 in light rain regime, especially over oceans, than those in V6. For light rain, rainfall estimates in V6 are less than those in V7 over land and oceans in both seasons. For moderate rain, rainfall estimates in V6 are larger than those in V7 over land in most years. Over oceans, it is a mixed situation in which V6 > V7 for some years and V6 < V7 for the other years. For heavy rain, rainfall estimates in V6 are larger than those in V7 throughout all JJA and DJF seasons for both land and oceans, which is also shown in a case study. Large variance in the individual differences is found in light rain and less in heavy rain. No apparent trends are observed. For light rain, all statistics support that there is an uncertainty issue in both versions.

  5. Evaluating the drought response of CMIP5 models using global gross primary productivity, leaf area, precipitation, and soil moisture data

    NASA Astrophysics Data System (ADS)

    Huang, Yuanyuan; Gerber, Stefan; Huang, Tongyi; Lichstein, Jeremy W.

    2016-12-01

    Realistic representation of vegetation's response to drought is important for understanding terrestrial carbon cycling. We evaluated nine Earth system models from the historical experiment of the Coupled Model Intercomparison Project Phase 5 for the response of gross primary productivity (GPP) and leaf area index (LAI) to hydrological anomalies. Hydrological anomalies were characterized by the standardized precipitation index (SPI) and surface soil moisture anomalies (SMA). GPP and LAI in models were on average more responsive to SPI than in observations revealed through several indicators. First, we find higher mean correlations between global annual anomalies of GPP and SPI in models than observations. Second, the maximum correlation between GPP and SPI across 1-24 month time scales is higher in models than observations. And finally, we found stronger excursions of GPP to extreme dry or wet events. Similar to GPP, LAI responded more to SPI in models than observations. The over-response of models is smaller if evaluated based on SMA instead of SPI. LAI responses to SMA are inconsistent among models, showing both higher and lower LAI when soil moisture is reduced. The time scale of maximum correlation is shorter in models than the observation for GPP, and the markedly different response time scales among models for LAI indicate gaps in understanding how variability of water availability affects foliar cover. The discrepancy of responses derived from SPI and SMA among models, and between models and observations, calls for improvement in understanding the dynamics of plant-available water in addition to how vegetation responds to these anomalies.

  6. Comparing the skill of precipitation forecasts from high resolution simulations and statistically downscaled products in the Australian Snowy Mountains

    NASA Astrophysics Data System (ADS)

    Dai, J.; Chubb, T.; Manton, M.; Siems, S. T.

    2013-12-01

    Statistically significant improvements to a 'Poor Man's Ensemble' (PME) of coarse-resolution numeral precipitation forecast for the Australian Snowy Mountains can be achieved using a clustering algorithm. Daily upwind soundings are classified according to one of four clusters, which are employed to adjust the precipitation forecasts using a linear regression. This approach is a type of 'statistical downscaling', in that it relies on a historical relationship between observed and forecast precipitation amounts, and is a computationally cheap and fast way to improve forecast skill. For the 'wettest' class, the root-mean-square error for the one-day forecast was reduced from 26.98 to 17.08 mm, and for the second 'wet' class the improvement was from 8.43 to 5.57 mm. Regressions performed for the two 'dry' classes were not shown to significantly improve the forecast. Statistical measures of the probability of precipitation and the quantitative precipitation forecast were evaluated for the whole of the 2011 winter (May-September). With a 'hit rate' (fraction of correctly-forecast rain days) of 0.9, and a 'false alarm rate' (fraction of forecast rain days which did not occur) of 0.16 the PME forecast performs well in identifying rain days. The precipitation amount is, however systematically under-predicted, with a mean bias of -5.76 mm and RMSE of 12.86 mm for rain days during the 2011 winter. To compare the statistically downscaled results with the capabilities of a state of the art numerical prediction system, the WRF model was run at 4 km resolution over the Australian Alpine region for the same period, and precipitation forecasts analysed in a similar manner. It had a hit rate of 0.955 and RMSE of 5.16 mm for rain days. The main reason for the improved performance relative to the PME is that the high resolution of the simulations better captures the orographic forcing due to the terrain, and consequently resolves the precipitation processes more realistically, but

  7. High precipitation rate in a Middle Triassic carbonate platform: Implications on the relationship between seawater saturation state and carbonate production

    NASA Astrophysics Data System (ADS)

    Franceschi, Marco; Preto, Nereo; Marangon, Alessandro; Gattolin, Giovanni; Meda, Marco

    2016-06-01

    Three-dimensional geological modeling of the Middle Triassic Latemar carbonate platform is coupled with facies modal analysis to estimate its carbonate precipitation rate (G). The 3D model, strongly constrained by field data, encompasses a specific stratigraphic interval of the platform, bounded by two isochronous surfaces. Modal analysis of thin sections allows estimating the proportion of syndepositional vs postdepositional carbonate in the facies associations of the platform. This, together with the 3D facies distribution in the model that takes into account lateral and vertical facies variability, permits to calculate the volumes of syndepositional carbonate preserved at Latemar between the two considered isochrones. Given the peculiar characteristics of the platform, that does not show evidences of strong dissolution processes or large carbonate mass loss through export in the nearby basins, results can be used to estimate the average precipitation rate of the platform in the considered time interval. This estimate allows discussion in relation to models of ocean water saturation state (Ω) with respect to carbonates in the geological past, and comparison to the calculated precipitation rates of modern tropical coral reef ecosystems at global and reef scale. A high G value is found at Latemar and represents the first empirical confirmation that, in the Triassic, extremes in Ω may have triggered high carbonate precipitation in shallow water settings; moreover, comparison to modern reefs points to a possible common relationship that may link seawater Ω and precipitation rate in carbonate platform ecosystems through geological time.

  8. Effects of Altered Seasonality of Precipitation on Grass Production and Grasshopper Performance in a Northern Mixed Prairie.

    PubMed

    Branson, David H

    2017-03-15

    Climatic changes are leading to differing patterns and timing of precipitation in grassland ecosystems, with the seasonal timing of precipitation affecting plant biomass and plant composition. No previous studies have examined how drought seasonality affects grasshopper performance and the impact of herbivory on vegetation. We modified seasonal patterns of precipitation and grasshopper density in a manipulative experiment to examine if seasonality of drought combined with herbivory affected plant biomass, nitrogen content, and grasshopper performance. Grass biomass was affected by both precipitation and grasshopper density treatments, while nitrogen content of grass was higher with early-season drought. Proportional survival was negatively affected by initial density, while survival was higher with early drought than with full-season drought. Drought timing affected the outcome, with early summer drought increasing grass nitrogen content and grasshopper survival, while season-long and late-season drought did not. The results support arguments that our knowledge of plant responses to seasonal short-term variation in climate is limited and illustrate the importance of experiments manipulating precipitation phenology. The results confirm that understanding the season of drought is critical for predicting grasshopper population dynamics, as extreme early summer drought may be required to strongly affect Melanoplus sanguinipes (F.) performance.

  9. Production of Chondroitin Sulphate from Head, Skeleton and Fins of Scyliorhinus canicula By-Products by Combination of Enzymatic, Chemical Precipitation and Ultrafiltration Methodologies

    PubMed Central

    Blanco, María; Fraguas, Javier; Sotelo, Carmen G.; Pérez-Martín, Ricardo I.; Vázquez, José Antonio

    2015-01-01

    This study illustrates the optimisation of the experimental conditions of three sequential steps for chondroitin sulphate (CS) recovery from three cartilaginous materials of Scyliorhinus canicula by-products. Optimum conditions of temperature and pH were first obtained for alcalase proteolysis of head cartilage (58 °C/pH 8.5/0.1% (v/w)/10 h of hydrolysis). Then, similar optimal conditions were observed for skeletons and fin materials. Enzymatic hydrolysates were subsequently treated with a combination of alkaline hydroalcoholic saline solutions in order to improve the protein hydrolysis and the selective precipitation of CS. Ranges of 0.53–0.64 M (NaOH) and 1.14–1.20 volumes (EtOH) were the levels for optimal chemical treatment depending on the cartilage origin. Finally, selective purification and concentration of CS and protein elimination of samples obtained from chemical treatment, was assessed by a combination of ultrafiltration and diafiltration (UF-DF) techniques at 30 kDa. PMID:26023837

  10. Quality control, data base and gridded analysis products provided by the Global Precipitation Climatology Centre (GPCC) to serve the hydro-climatology community

    NASA Astrophysics Data System (ADS)

    Ziese, M.; Becker, A.; Schneider, U.; Meyer-Christoffer, A.; Finger, P.; Rudolf, B.

    2011-12-01

    Since its start in 1989 the Global Precipitation Climatology Centre (GPCC) performs global analyses of monthly precipitation for the earth's land-surface on the basis of in-situ measurements. Meanwhile, the data set has continuously grown both in temporal coverage (original start of the evaluation period was 1986), as well as extent and quality of the underlying data base. The high spatio-temporal variability of precipitation requires a high density of measurement data. The GPCC receives the SYNOP and CLIMAT messages in near real-time via the WMO GTS. Core data source of the GPCC analyses are the data from station networks operated by the National Meteorological/Hydrological Services worldwide; data deliveries have been received from ca. 190 countries. The GPCC integrates also other global precipitation data collections (i.e. FAO, CRU and GHCN), as well as regional data sets and has recently started collection and analysis of daily data while keeping its other activities upright. As a result of these efforts the GPCC holds the worldwide largest and most comprehensive collection of precipitation data, which is continuously updated and extended. The acquired data sets are pre-checked and imported into a relational data base, thus allowing a cross-comparison of data from the different sources. Any time new data sets are imported to the data base the metadata in the input data set are compared to those already available. Since the beginning of 2009 the precipitation data to be imported is compared against a background statistic. Exceptional values are checked and either confirmed, corrected or excluded from the analyses. Near-real-time products are the 'First Guess Product' (created for early detection, e.g., drought monitoring) and 'Monitoring Product' (created on WCRP request and for merging to satellite data), both with a spatial resolution of 1°x1°. Only an automatic quality control runs during the generation of the 'First Guess Product', whereas the data base is

  11. Relationship between extreme Precipitation and Temperature over Japan: An analysis from Multi-GCMs and Multi-RCMs products

    NASA Astrophysics Data System (ADS)

    Nayak, S.; Dairaku, K.; Takayabu, I.

    2014-12-01

    According to the IPCC reports, the concentration of CO­2 has been increasing and projected to be increased significantly in future (IPCC, 2012). This can have significant impacts on climate. For instance, Dairaku and Emori (2006) examined over south Asia by doubling CO2 and documented an increase in precipitation intensities during Indian summer monsoon. This would increase natural disasters such as floods, landslide, coastal disaster, erosion etc. Recent studies investigated whether the rate of increase of extreme precipitation is related with the rate expected by Clausius-Clapeyron (CC) relationship (approximately 7% per degree temperature rise). In our study, we examine whether this rate can increase or decrease in the future regional climate scenarios over Japan. We have analysed the ensemble experiments by three RCMs(NHRCM, NRAMS, WRF) forced by JRA25 as well as three GCMs (CCSM4, MIROC5, MRI-GCM3) for the current climate (1981-2000) and future scenario (2081-2100, RCP4.5) over Japan. We have stratified the extreme (99th, 95th, 90th, 75th percentile) precipitation of daily sum and daily maximum of hourly precipitation intensities of wet events based on daily mean temperature in bins of 1°C width for annual as well as for each season (DJF, MAM, JJA, SON). The results indicate that precipitation intensity increases when temperature increases roughly up to 22 °C and further increase of temperature decreases the precipitation intensities. The obtained results are consistent and match with the observation (APHRODITE dataset) over Japan. The decrease of precipitation at higher temperature mainly can be found in JJA. It is also noticed that the rate of specific humidity is estimated higher during JJA than other seasons. The rate of increase of extreme precipitation is similar to the rate expected by CC relation except DJF (nearly twice of CC relation) in current climate. This rate becomes to be significantly larger in future scenario for higher temperatures than

  12. Accuracy of rainfall estimates at high altitude in the Garhwal Himalaya (India): A comparison of secondary precipitation products and station rainfall measurements

    NASA Astrophysics Data System (ADS)

    Bhardwaj, Alok; Ziegler, Alan D.; Wasson, Robert J.; Chow, Winston T. L.

    2017-05-01

    Accurate estimation of the magnitude and spatio-temporal variability of rainfall in the Indian Himalaya is difficult because of the sparse and limited network of ground stations located within complex terrain, as well as the difficulty of maintaining the stations over time. Thus, secondary rainfall sources are important to hydrological and hazard studies, if they reproduce the dynamics of rainfall satisfactorily. In this work, we evaluate four secondary products in the Garhwal Himalaya in India, with a focus on their application within the Mandakini River Catchment, the site of a devastating flood and multiple large landslides in 2013. The analysis included two satellite products: from the Tropical Rainfall Measuring Mission (TRMM) and the Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN) program, as well as two gridded products: the Asian Precipitation Highly Resolved Observational Data Integration Towards Evaluation of Water Resources (APHRODITE) product and the India Meteorological Department (IMD) product. In comparing the four products against data collected at four ground stations (Rudraprayag, Joshimath, Purola, and Mukhim) using a variety of statistical indices, we determined that the IMD and TRMM products were superior to the others. In particular, the IMD product ranked the best for most indices including probability of detection (POD), false alarm ratio (FAR), receiver operating curve (ROC), and root mean squared error (RMSE). The TRMM product performed satisfactorily in terms of bias and detecting daily maximum monsoon rainfall at three of the four stations. The APHRODITE product had POD, FAR and ROC values that were among the best at higher rainfall depths at the Mukhim station. The PERSIANN product generally did not perform well based on these indices, consistently underestimating station rainfall depths. Finally, the IMD product could document the daily rainfall distribution during the June 2013

  13. a Landscape Perspective of Ephemeral Erosion: Topographic Parameters Associated with Soil Property, Soil Productivity, and Precipitation Patterns

    NASA Astrophysics Data System (ADS)

    Lentz, Rodrick David

    The pattern of ephemeral gully erosion and crop productivity was investigated in three different southeastern Minnesota soilscapes during 1988 and 1989. In addition, the role that local or regional landscape configuration has in controlling distribution of precipitation in agricultural landscapes was investigated. A full-scale model of a small hill was instrumented to measure rainfall intensity across its surface. The model was employed to test for wind-terrain interactions and to determine if these effects conform to the drift theory. Another study sought to identify local and topographic parameters associated with deposition and redistribution of snow in agricultural landscapes having complex relief. In 1989 soil lost from ephemeral gullies ranged from 0.8 to 1.6 Mg/ha at the study sites. Soil loss at the Mower county site ranged from 0.8 to 9.8 Mg/ha during '86, '87, and '89 seasons. Crop yield of gullied areas was not significantly different (a = 0.05) than that of adjacent non-gullied areas during the two relatively dry years, 1988 and 1989. Mid-channel reaches were most sensitive to effects of erosion. Topographically sensitive controls of ephemeral erosion, such as surface saturation and stream transport capacity, played different roles in channel formation at each site. Hydrologic rainfall varied by as much as 36% across hill model surfaces. A wind-terrain interaction occurred at all summit elevations tested (0.9, 2.1, and 2.7 m), and over a range of incident wind speeds (1 to 11 m s ^{-1}) and meteorological rainfall rates (1 to 100 mm hr^{-1}). Rainfall vector analysis indicated that a drifting process was partially responsible for the observed rainfall pattern. The drift theory did not explain decreasing rainfall incidence observed from lower to upper windward slopes. Snowfall deposition was nonuniform at mean event wind speeds above 1.2 m s^{-1} . Greatest variation in snow depth, typically about 400%, was observed when mean event wind speeds exceeded 3

  14. SPECIAL SESSION: (H21) on Global Precipitation Mission for Hydrology and Hydrometeorology. Sampling-Error Considerations for GPM-Era Rainfall Products

    NASA Technical Reports Server (NTRS)

    Bell, Thomas L.; Lau, William K. M. (Technical Monitor)

    2002-01-01

    The proposed Global Precipitation Mission (GPM) builds on the success of the Tropical Rainfall Measuring Mission (TRMM), offering a constellation of microwave-sensor-equipped smaller satellites in addition to a larger, multiply-instrumented "mother" satellite that will include an improved precipitation radar system to which the precipitation estimates of the smaller satellites can be tuned. Coverage by the satellites will be nearly global rather than being confined as TRMM was to lower latitudes. It is hoped that the satellite constellation can provide observations at most places on the earth at least once every three hours, though practical considerations may force some compromises. The GPM system offers the possibility of providing precipitation maps with much better time resolution than the monthly averages around which TRMM was planned, and therefore opens up new possibilities for hydrology and data assimilation into models. In this talk, methods that were developed for estimating sampling error in the rainfall averages that TRMM is providing will be used to estimate sampling error levels for GPM-era configurations. Possible impacts on GPM products of compromises in the sampling frequency will be discussed.

  15. SPECIAL SESSION: (H21) on Global Precipitation Mission for Hydrology and Hydrometeorology. Sampling-Error Considerations for GPM-Era Rainfall Products

    NASA Technical Reports Server (NTRS)

    Bell, Thomas L.; Lau, William K. M. (Technical Monitor)

    2002-01-01

    The proposed Global Precipitation Mission (GPM) builds on the success of the Tropical Rainfall Measuring Mission (TRMM), offering a constellation of microwave-sensor-equipped smaller satellites in addition to a larger, multiply-instrumented "mother" satellite that will include an improved precipitation radar system to which the precipitation estimates of the smaller satellites can be tuned. Coverage by the satellites will be nearly global rather than being confined as TRMM was to lower latitudes. It is hoped that the satellite constellation can provide observations at most places on the earth at least once every three hours, though practical considerations may force some compromises. The GPM system offers the possibility of providing precipitation maps with much better time resolution than the monthly averages around which TRMM was planned, and therefore opens up new possibilities for hydrology and data assimilation into models. In this talk, methods that were developed for estimating sampling error in the rainfall averages that TRMM is providing will be used to estimate sampling error levels for GPM-era configurations. Possible impacts on GPM products of compromises in the sampling frequency will be discussed.

  16. Precipitation Recycling

    NASA Technical Reports Server (NTRS)

    Eltahir, Elfatih A. B.; Bras, Rafael L.

    1996-01-01

    The water cycle regulates and reflects natural variability in climate at the regional and global scales. Large-scale human activities that involve changes in land cover, such as tropical deforestation, are likely to modify climate through changes in the water cycle. In order to understand, and hopefully be able to predict, the extent of these potential global and regional changes, we need first to understand how the water cycle works. In the past, most of the research in hydrology focused on the land branch of the water cycle, with little attention given to the atmospheric branch. The study of precipitation recycling which is defined as the contribution of local evaporation to local precipitation, aims at understanding hydrologic processes in the atmospheric branch of the water cycle. Simply stated, any study on precipitation recycling is about how the atmospheric branch of the water cycle works, namely, what happens to water vapor molecules after they evaporate from the surface, and where will they precipitate?

  17. Precipitation Recycling

    NASA Technical Reports Server (NTRS)

    Eltahir, Elfatih A. B.; Bras, Rafael L.

    1996-01-01

    The water cycle regulates and reflects natural variability in climate at the regional and global scales. Large-scale human activities that involve changes in land cover, such as tropical deforestation, are likely to modify climate through changes in the water cycle. In order to understand, and hopefully be able to predict, the extent of these potential global and regional changes, we need first to understand how the water cycle works. In the past, most of the research in hydrology focused on the land branch of the water cycle, with little attention given to the atmospheric branch. The study of precipitation recycling which is defined as the contribution of local evaporation to local precipitation, aims at understanding hydrologic processes in the atmospheric branch of the water cycle. Simply stated, any study on precipitation recycling is about how the atmospheric branch of the water cycle works, namely, what happens to water vapor molecules after they evaporate from the surface, and where will they precipitate?

  18. STRONTIUM PRECIPITATION

    DOEpatents

    McKenzie, T.R.

    1960-09-13

    A process is given for improving the precipitation of strontium from an aqueous phosphoric-acid-containing solution with nickel or cobalt ferrocyanide by simultaneously precipitating strontium or calcium phosphate. This is accomplished by adding to the ferrocyanide-containing solution calcium or strontium nitrate in a quantity to yield a concentration of from 0.004 to 0.03 and adjusting the pH of the solution to a value of above 8.

  19. Production and precipitation of rare earth elements in acidic to alkaline coal mine discharges, Appalachian Basin, USA

    NASA Astrophysics Data System (ADS)

    Stewart, B. W.; Capo, R. C.; Hedin, B. C.; Wallrich, I. L. R.; Hedin, R. S.

    2016-12-01

    Abandoned coal mine discharges are a serious threat to ground and surface waters due to their high metal content and often high acidity. However, these discharges represent a potential source of rare earth elements (REE), many of which are considered to be critical resources. Trace element data from 18 coal mine drainage (CMD) sites within the Appalachian Basin suggest CMD is enriched in total REE by 1-4 orders of magnitude relative to concentrations expected in unaffected surface or ground waters. When normalized to the North American Shale Composite (NASC), the discharges generally show a pattern of enrichment in the middle REE, including several identified as critical resources (Nd, Eu, Dy, Tb). In contrast, shale, sandstone and coal samples from Appalachian Basin coal-bearing units have concentrations and patterns similar to NASC, indicating that the REE in CMD are fractionated during interaction with rock in the mine pool. The highest total REE contents (up to 2800 mg/L) are found in low-pH discharges (acid mine drainage, or AMD). A precipitous drop in REE concentration in CMD with pH ≥6.6 suggests adsorption or precipitation of REE in the mine pool at circumneutral pH. Precipitated solids from 21 CMD active and passive treatment sites in the Appalachian Basin, including Fe oxy-hydroxides, Ca-Mg lime slurries, and Si- and Al-rich precipitates, are enriched in total REE content relative to the average CMD discharges by about four orders of magnitude. Similar REE trends in the discharges and precipitates, including MREE enrichment, suggest minimal fractionation of REE during precipitation; direct comparisons over multiple seasonal cycles are needed to confirm this. Although the data are limited, Al-rich precipitates generally have high REE concentrations, while those in iron oxy-hydroxides tend to be lower. Based on the area of mined coal in the Appalachian Basin, estimated infiltration rates, and the mean REE flux from discharges analyzed in this study and

  20. MWRRET Value-Added Product: The Retrieval of Liquid Water Path and Precipitable Water Vapor from Microwave Radiometer (MWR) Datasets May 2009

    SciTech Connect

    Gaustad, KL; Turner, DD

    2009-05-30

    This report provides a short description of the Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) microwave radiometer (MWR) RETrievel (MWRRET) value-added product (VAP) algorithm. This algorithm utilizes a complementary physical retrieval method and applies brightness temperature offsets to reduce spurious liquid water path (LWP) bias in clear skies resulting in significantly improved precipitable water vapor (PWV) and LWP retrievals. We present a general overview of the technique, input parameters, output products, and describe data quality checks. A more complete discussion of the theory and results is given in Turner et al. (2007b).

  1. MWRRET Value-Added Product: The Retrieval of Liquid Water Path and Precipitable Water Vapor from Microwave Radiometer (MWR) Data Sets (Revision 2)

    SciTech Connect

    Gaustad, KL; Turner, DD; McFarlane, SA

    2011-07-25

    This report provides a short description of the Atmospheric Radiation Measurement (ARM) Climate Research Facility microwave radiometer (MWR) Retrieval (MWRRET) value-added product (VAP) algorithm. This algorithm utilizes a complementary physical retrieval method and applies brightness temperature offsets to reduce spurious liquid water path (LWP) bias in clear skies resulting in significantly improved precipitable water vapor (PWV) and LWP retrievals. We present a general overview of the technique, input parameters, output products, and describe data quality checks. A more complete discussion of the theory and results is given in Turner et al. (2007b).

  2. Production and Precipitation Hardening of Beta-Type Ti-35Nb-10Cu Alloy Foam for Implant Applications

    NASA Astrophysics Data System (ADS)

    Mutlu, Ilven; Yeniyol, Sinem; Oktay, Enver

    2016-04-01

    In this study, beta-type Ti-35Nb-10Cu alloy foams were produced by powder metallurgy method for dental implant applications. 35% Nb was added to stabilize the beta-Ti phase with low Young's modulus. Cu addition enhanced sinterability and gave precipitation hardening capacity to the alloy. Sintered specimens were precipitation hardened in order to enhance the mechanical properties. Electrochemical corrosion behavior of the specimens was examined by electrochemical impedance spectroscopy in artificial saliva. Electrochemical impedance spectroscopy results indicated that the oxide film on the surface of foam is a bi-layer structure consisting of outer porous layer and inner barrier layer. Impedance values of barrier layer were higher than porous layer. Corrosion resistance of specimens decreased at high fluoride concentrations and at low pH of artificial saliva. Corrosion resistance of alloys was slightly decreased with aging. Mechanical properties, microstructure, and surface roughness of the specimens were also examined.

  3. A three-prong strategy to develop functional food using protein isolates recovered from chicken processing by-products with isoelectric solubilization/precipitation.

    PubMed

    Tahergorabi, Reza; Sivanandan, Litha; Beamer, Sarah K; Matak, Kristen E; Jaczynski, Jacek

    2012-09-01

    Skin-on bone-in chicken drumsticks were processed with isoelectric solubilization/precipitation to recover muscle proteins. The drumsticks were used as a model for dark chicken meat processing by-products. The main objective of this study was conversion of dark chicken meat processing by-products to restructured functional food product. An attempt was made to develop functional food product that would resemble respective product made from boneless skinless chicken breast meat. A three-prong strategy to address diet-driven cardiovascular disease (CVD)with a functional food was used in this study. The strategy included addition of three ingredients with well-documented cardiovascular benefits: (i) ω-3 polyunsaturated fatty acid-rich oil (flaxseed-algae, 9:1); (ii) soluble fiber; and (iii) salt substitute. Titanium dioxide, potato starch, polyphosphate, and transglutaminase were also added. The batters were formulated and cooked resulting in heat-set gels. Color (L*a*b*), texture (torsion test, Kramer shear test, and texture profile analysis), thermal denaturation (differential scanning calorimetry), and gelation (dynamic rheology) of chicken drumstick gels and chicken breast gels were determined and compared. Chicken drumstick gels generally had comparable color and texture properties to the gels made from chicken breast meat. The endothermic transition (thermal denaturation) of myosin was more pronounced and gelation properties were better for the drumstick gels. This study demonstrated a feasibility to develop functional food made of muscle proteins recovered with isoelectric solubilization/precipitation from low-value dark chicken meat processing by-products. The functional food developed in this study was enriched with CVD-beneficial nutrients and had comparable instrumental quality attributes to respective products made of chicken breast meat. Although the results of this study point towards the potential for a novel, marketable functional food product, sensory

  4. Electrostatic Precipitator

    NASA Image and Video Library

    2017-06-09

    In their Swamp Works laboratory at NASA's Kennedy Space Center, Dr. Carlos Calle and Jay Phillips are testing an electrostatic precipitator using dust that closely approximates the make-up of that on Mars. They upgraded their electrostatic precipitator to fully simulate Martian atmosphere by designing and constructing a dust aerosolization pre-chamber. The agency's Journey to Mars requires cutting-edge technologies to solve the problems explorers will face on the Red Planet. Scientists are developing some of the needed solutions by adapting a device to remove the ever-present dust from valuable elements in the Martian atmosphere. Those commodities include oxygen, water and methane.

  5. Statistical and Hydrological Evaluation of TRMM-Based Multi-Satellite Precipitation Analysis over the Wangchu Basin of Bhutan: Are the Latest Satellite Precipitation Products 3B42V7 Ready for Use in Ungauged Basins?

    NASA Technical Reports Server (NTRS)

    Xue, Xianwu; Hong, Yang; Limaye, Ashutosh S.; Gourley, Jonathan; Huffman, George J.; Khan, Sadiq Ibrahim; Dorji, Chhimi; Chen, Sheng

    2013-01-01

    The objective of this study is to quantitatively evaluate the successive Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) products and further to explore the improvements and error propagation of the latest 3B42V7 algorithm relative to its predecessor 3B42V6 using the Coupled Routing and Excess Storage (CREST) hydrologic model in the mountainous Wangchu Basin of Bhutan. First, the comparison to a decade-long (2001-2010) daily rain gauge dataset reveals that: 1) 3B42V7 generally improves upon 3B42V6s underestimation both for the whole basin (bias from -41.15 to -8.38) and for a 0.250.25 grid cell with high-density gauges (bias from -40.25 to 0.04), though with modest enhancement of correlation coefficients (CC) (from 0.36 to 0.40 for basin-wide and from 0.37 to 0.41 for grid); and 2) 3B42V7 also improves its occurrence frequency across the rain intensity spectrum. Using the CREST model that has been calibrated with rain gauge inputs, the 3B42V6-based simulation shows limited hydrologic prediction NSCE skill (0.23 in daily scale and 0.25 in monthly scale) while 3B42V7 performs fairly well (0.66 in daily scale and 0.77 in monthly scale), a comparable skill score with the gauge rainfall simulations. After recalibrating the model with the respective TMPA data, significant improvements are observed for 3B42V6 across all categories, but not as much enhancement for the already well-performing 3B42V7 except for a reduction in bias (from -26.98 to -4.81). In summary, the latest 3B42V7 algorithm reveals a significant upgrade from 3B42V6 both in precipitation accuracy (i.e., correcting the underestimation) thus improving its potential hydrological utility. Forcing the model with 3B42V7 rainfall yields comparable skill scores with in-situ gauges even without recalibration of the hydrological model by the satellite precipitation, a compensating approach often used but not favored by the hydrology community, particularly in ungauged basins.

  6. Impact of drought and precipitation seasonality on net primary production and plant community composition across a grassland ecotone in New Mexico

    NASA Astrophysics Data System (ADS)

    Collins, Scott; Thomey, Michell; Brown, Renee; Gehres, Nate; Petrie, Matthew; Vanderbilt, Kristin; Pockman, William

    2015-04-01

    In the southwestern US, climate change will impact the amount, timing and variability of rainfall during the summer monsoon. Changes in amount and seasonality of precipitation are likely to affect plant community dynamics and ecosystem processes, especially along ecotones. In 2012, we established a rainfall manipulation experiment (EDGE-Extreme Drought in Grasslands Experiment) in Chihuahuan Desert grassland (CDG) dominated by black grama and shortgrass steppe (SGS) dominated by blue grama across a grassland ecotone in central New Mexico. EDGE includes two rainfall treatments, chronic drought (~66% reduction in monsoon rainfall) and altered timing of the summer monsoon. Chronic drought is imposed from July through September by rainout shelters with roof panels that cover 66% of the surface area. To alter precipitation seasonality complete rainout shelters are erected in July and August, and all rainfall that occurred during this period is captured, stored, and then reapplied in several large rain events during September and October. Thus, this treatment receives the same amount of precipitation as ambient but differs in seasonality and frequency of rain events. We measured soil moisture, aboveground net primary production (ANPP), and plant species composition in each replicate (n=10) of each treatment at CDG and SGS sites. There were no significant pre-treatment differences in ANPP or plant species richness at either site. In 2013 following an above average monsoon, ambient ANPP was 99.4 g m-2 at CDG and 44.3 g m-2 at SGS. Event size reduction resulted in a 75% reduction in ANPP at CDG but only a 33% reduction in ANPP at SGS. Shifting the monsoon to later in the growing season resulted in a 50% and 43% reduction in ANPP at CDG and SGS, respectively. Thus, ANPP at CDG partially recovered from the mid-summer drought with late season precipitation but SGS did not. Event size reduction also resulted in a decrease in species richness at CDG, but not at SGS. These short

  7. Impact of Drought and Precipitation Seasonality on Net Primary Production and Plant Community Composition Across a Grassland Ecotone in New Mexico

    NASA Astrophysics Data System (ADS)

    Collins, S. L.; Thomey, M. L.; Brown, R. F.; Gehres, N.; Petrie, M. D.; Vanderbilt, K.; Pockman, W.

    2014-12-01

    In the southwestern US, climate change will impact the amount, timing and variability of rainfall during the summer monsoon. Changes in amount and seasonality of precipitation are likely to affect plant community dynamics and ecosystem processes, especially along ecotones. In 2012, we established a rainfall manipulation experiment (EDGE-Extreme Drought in Grasslands Experiment) in Chihuahuan Desert grassland (CDG) dominated by black grama and shortgrass steppe (SGS) dominated by blue grama across a grassland ecotone in central New Mexico. EDGE includes two rainfall treatments, chronic drought (~66% reduction in monsoon rainfall) and altered timing of the summer monsoon. Chronic drought is imposed from July through September by rainout shelters with roof panels that cover 66% of the surface area. To alter precipitation seasonality complete rainout shelters are erected in July and August, and all rainfall that occurred during this period is captured, stored, and then reapplied in several large rain events during September and October. Thus, this treatment receives the same amount of precipitation as ambient but differs in seasonality and frequency of rain events. We measured soil moisture, aboveground net primary production (ANPP), and plant species composition in each replicate (n=10) of each treatment at CDG and SGS sites. There were no significant pre-treatment differences in ANPP or plant species richness at either site. In 2013 following an above average monsoon, ambient ANPP was 99.4 g m-2 at CDG and 44.3 g m-2 at SGS. Event size reduction resulted in a 75% reduction in ANPP at CDG but only a 33% reduction in ANPP at SGS. Shifting the monsoon to later in the growing season resulted in a 50% and 43% reduction in ANPP at CDG and SGS, respectively. Thus, ANPP at CDG partially recovered from the mid-summer drought with late season precipitation but SGS did not. Event size reduction also resulted in a decrease in species richness at CDG, but not at SGS. These short

  8. Validating NEXRAD MPE and Stage III precipitation products for uniform rainfall on the Upper Guadalupe River Basin of the Texas Hill Country

    NASA Astrophysics Data System (ADS)

    Wang, Xianwei; Xie, Hongjie; Sharif, Hatim; Zeitler, Jon

    2008-01-01

    SummaryThis study examines the performance of the Next Generation Weather Radar (NEXRAD) Multisensor Precipitation Estimator (MPE) and Stage III precipitation products, using a high-density rain gauge network located on the Upper Guadalupe River Basin of the Texas Hill Country. As point-area representativeness error of gauge rainfall is a major concern in assessment of radar rainfall estimation, this study develops a new method to automatically select uniform rainfall events based on coefficient of variation criterion of 3 by 3 radar cells. Only gauge observations of those uniform rainfall events are used as ground truth to evaluate radar rainfall estimation. This study proposes a new parameter probability of rain detection (POD) instead of the conditional probability of rain detection (CPOD) commonly used in previous studies to assess the capability that a radar or gauge detects rainfall. Results suggest that: (1) gauge observations of uniform rainfall better represent ground truth of a 4 × 4 km 2 radar cell than non-uniform rainfall; (2) the MPE has higher capability of rain detection than either gauge-only or Stage III; (3) the MPE has much higher linear correlation and lower mean relative difference with gauge measurements than the Stage III does; (4) the Stage III tends to overestimate precipitation (20%), but the MPE tends to underestimate (7%).

  9. Precipitation Matters

    ERIC Educational Resources Information Center

    McDuffie, Thomas

    2007-01-01

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

  10. Precipitation Matters

    ERIC Educational Resources Information Center

    McDuffie, Thomas

    2007-01-01

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

  11. Analysis of the Diurnal Cycle of Precipitation and its Relation to Cloud Radiative Forcing using TRMM Products

    NASA Technical Reports Server (NTRS)

    Randall, David A.; Fowler, Laura D.

    2000-01-01

    By incorporating the Tropical Rain Measuring Mission (TRMM) satellite orbital information into the geodesic version of the Colorado State University General Circulation Model (CSU GCM), we are able to fly a satellite in the GCM, and sample the simulated atmosphere in the same way as the TRMM sensors sample the real atmosphere. The TRMM sampling statistics of precipitation and radiative fluxes at annual, intraseasonal, monthly-mean and composited diurnal time scales are evaluated by comparing the satellite-sampled against fully-sampled simulated atmospheres. This information provides a valuable guidance for efficient usage of TRMM data and future satellite mission planning.

  12. Speleothems in a wave-cut notch, Cayman Brac, British West Indies: The integrated product of subaerial precipitation, dissolution, and microbes

    NASA Astrophysics Data System (ADS)

    Jones, Brian

    2010-12-01

    A wave-cut notch that is deeply incised into the vertical cliff faces of Cayman Brac is adorned with stalactites, stalagmites, and columns. The prefix "notch" is applied to each type of speleothem in order to distinguish them from cave speleothems. These speleothemic deposits must have formed since the highstand, ~ 125,000 years ago, which was responsible for the development of the notch. The laminated notch speleothems are formed largely of aragonite (small and large crystals) and calcite (columnar, fiber, and grain-coating mats) along with minor amounts of dolomite, a Mg-Si precipitate (kerolite?), gypsum, and halite. Laminae, typically < 2 mm thick, are commonly bounded by dissolution discontinuities that truncate the older laminae and their formative aragonite and calcite crystals. The patchy tan, grey, to green surface coloration of the notch speleothems reflects the random distribution of the subaerial biofilms, which are formed of a diverse array of filamentous and non-filamentous microbes. The notch speleothems are the integrated product of precipitation and dissolution that was, in some places, microbially mediated. Interpretations based on their mineralogy and internal structures indicate that the composition of the formative waters must have temporally fluctuated with periods of precipitation being interrupted by periods of dissolution. The microbes that formed the subaerial biofilms may have influenced some of these processes. The aragonite, calcite, and kerolite (?) probably formed as evaporation and loss of Ca through precipitation progressively increased the Mg:Ca and the Si/(Ca + Mg) ratios. The dolomite, gypsum, and halite probably formed during early diagenesis during the evaporation of seawater that percolated into the interiors of the notch speleothems.

  13. Definition and impact of a quality index for radar-based reference measurements in the H-SAF precipitation product validation

    NASA Astrophysics Data System (ADS)

    Rinollo, A.; Vulpiani, G.; Puca, S.; Pagliara, P.; Kaňák, J.; Lábó, E.; Okon, L'.; Roulin, E.; Baguis, P.; Cattani, E.; Laviola, S.; Levizzani, V.

    2013-10-01

    The EUMETSAT Satellite Application Facility on Support to Operational Hydrology and Water Management (H-SAF) provides rainfall estimations based on infrared and microwave satellite sensors on board polar and geostationary satellites. The validation of these satellite estimations is performed by the H-SAF Precipitation Product Validation Group (PPVG). A common validation methodology has been defined inside the PPVG in order to make validation results from several institutes comparable and understandable. The validation of the PR-OBS-3 (blended infrared-microwave (IR-MW) instantaneous rainfall estimation) product using radar-based rainfall estimations as ground reference is described herein. A network of C-band and Ka-band radars throughout Europe ensures a wide area coverage with different orographic configurations and climatological regimes, but the definition of a quality control protocol for obtaining consistent ground precipitation fields across several countries is required. Among the hydro-meteorological community, the evaluation of the data quality is a quite consolidated practice, even though a unique definition of a common evaluation methodology between different countries and institutions has not been set up yet. Inside H-SAF, the first definition of the quality index of the radar rainfall observations has been introduced at the Italian Civil Protection Department (DPC). In the evaluation of the DPC quality index, several parameters are considered, some measured by the radar itself (static clutter map, range distance, radial velocity, texture of differential reflectivity, texture of co-polar correlation coefficient and texture of differential phase shift) and some obtained by external sources (digital elevation model, freezing layer height). In some cases, corrections were applied for clutter and beam blocking. The DPC quality index was calculated and applied to some relevant meteorological events reported by a radar test site in Italy. The precipitation

  14. Ecohydrology of a semi-arid forest: effects of precipitation pattern and canopy structure on forest productivity

    NASA Astrophysics Data System (ADS)

    Raz Yaseef, N.; Rotenberg, E.; Schiller, G.; Yakir, D.

    2009-12-01

    In dry forest ecosystems water is often the main limitation to carbon sequestration and water availability to the trees is further limited by losses to soil evaporation (E). While it is important to assess E, it is also a difficult variable to directly measure, and can be expected to be highly heterogeneous in open-canopies. We investigated the links between the water and carbon cycles in a semi-arid forest in Southern-Israel (40-year-old P. halepensis forest, with LAI of 1.5 and mean annual precipitation of 285 mm). During a four-year research period we measured precipitation (P, event rain gauges), soil water content (TDRs), evapotranspiration (ET, eddy covariance), tree transpiration (T, sap flux), soil evaporation (E, soil chambers) and intercepted precipitation (calculated). These were combined with on-going measurements of net ecosystem CO2 exchange (NEE), radiation budget and meteorological measurements. On average for the study period, ET accounted for 94% of P, varying between 100% when P<250 mm and 85% when P>300 mm (with indications for losses to subsurface flow and soil moisture storage in wetter years). Both T and E were major fluxes in this dry forest: 45% and 36% of ET, respectively. Two main processes influenced the partitioning of ET between E and T: precipitation patterns and canopy structure. The pulsed-storm pattern, characteristic of semi-arid climates, was sufficient to maintain the topsoil layer wet during the whole wet season (November to March), producing high E during high radiation days (up to 0.70 mm d-1 in the wetting and drying seasons). Only infrequent and relatively intensive storms resulted in infiltration to the depth of maximum rooting density (~25cm) and below, increasing water availability to the trees. As a result, two years with similar P (231 and 224 mm) had different ecosystem water use efficiency: 1.06 (gCO2/kgH2O) in a year with few large storms, but only 0.74 in a year with many small storms. The spatial variability in E

  15. Global Precipitation Measurement (GPM) Mission Products and Services at the NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC)

    NASA Astrophysics Data System (ADS)

    Ostrenga, D.; Liu, Z.; Vollmer, B.; Teng, W. L.; Kempler, S. J.

    2014-12-01

    On February 27, 2014, the NASA Global Precipitation Measurement (GPM) mission was launched to provide the next-generation global observations of rain and snow (http://pmm.nasa.gov/GPM). The GPM mission consists of an international network of satellites in which a GPM "Core Observatory" satellite carries both active and passive microwave instruments to measure precipitation and serve as a reference standard, to unify precipitation measurements from a constellation of other research and operational satellites. The NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC) hosts and distributes GPM data within the NASA Earth Observation System Data Information System (EOSDIS). The GES DISC is home to the data archive for the GPM predecessor, the Tropical Rainfall Measuring Mission (TRMM). Over the past 16 years, the GES DISC has served the scientific as well as other communities with TRMM data and user-friendly services. During the GPM era, the GES DISC will continue to provide user-friendly data services and customer support to users around the world. GPM products currently and to-be available include the following: Level-1 GPM Microwave Imager (GMI) and partner radiometer products Goddard Profiling Algorithm (GPROF) GMI and partner products Integrated Multi-satellitE Retrievals for GPM (IMERG) products (early, late, and final) A dedicated Web portal (including user guides, etc.) has been developed for GPM data (http://disc.sci.gsfc.nasa.gov/gpm). Data services that are currently and to-be available include Google-like Mirador (http://mirador.gsfc.nasa.gov/) for data search and access; data access through various Web services (e.g., OPeNDAP, GDS, WMS, WCS); conversion into various formats (e.g., netCDF, HDF, KML (for Google Earth), ASCII); exploration, visualization, and statistical online analysis through Giovanni (http://giovanni.gsfc.nasa.gov); generation of value-added products; parameter and spatial subsetting; time aggregation; regridding

  16. Global Precipitation Measurement (GPM) Mission Products and Services at the NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC)

    NASA Technical Reports Server (NTRS)

    Liu, Zhong; Ostrenga, D.; Vollmer, B.; Deshong, B.; Greene, M.; Teng, W.; Kempler, S. J.

    2015-01-01

    On February 27, 2014, the NASA Global Precipitation Measurement (GPM) mission was launched to provide the next-generation global observations of rain and snow (http:pmm.nasa.govGPM). The GPM mission consists of an international network of satellites in which a GPM Core Observatory satellite carries both active and passive microwave instruments to measure precipitation and serve as a reference standard, to unify precipitation measurements from a constellation of other research and operational satellites. The NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC) hosts and distributes GPM data within the NASA Earth Observation System Data Information System (EOSDIS). The GES DISC is home to the data archive for the GPM predecessor, the Tropical Rainfall Measuring Mission (TRMM). Over the past 16 years, the GES DISC has served the scientific as well as other communities with TRMM data and user-friendly services. During the GPM era, the GES DISC will continue to provide user-friendly data services and customer support to users around the world. GPM products currently and to-be available include the following: 1. Level-1 GPM Microwave Imager (GMI) and partner radiometer products. 2. Goddard Profiling Algorithm (GPROF) GMI and partner products. 3. Integrated Multi-satellitE Retrievals for GPM (IMERG) products. (early, late, and final)A dedicated Web portal (including user guides, etc.) has been developed for GPM data (http:disc.sci.gsfc.nasa.govgpm). Data services that are currently and to-be available include Google-like Mirador (http:mirador.gsfc.nasa.gov) for data search and access; data access through various Web services (e.g., OPeNDAP, GDS, WMS, WCS); conversion into various formats (e.g., netCDF, HDF, KML (for Google Earth), ASCII); exploration, visualization, and statistical online analysis through Giovanni (http:giovanni.gsfc.nasa.gov); generation of value-added products; parameter and spatial subsetting; time aggregation; regridding; data

  17. Global Precipitation Measurement (GPM) Mission Products and Services at the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC)

    NASA Technical Reports Server (NTRS)

    Ostrenga, D.; Liu, Z.; Vollmer, B.; Teng, W.; Kempler, S.

    2014-01-01

    On February 27, 2014, the NASA Global Precipitation Measurement (GPM) mission was launched to provide the next-generation global observations of rain and snow (http:pmm.nasa.govGPM). The GPM mission consists of an international network of satellites in which a GPM Core Observatory satellite carries both active and passive microwave instruments to measure precipitation and serve as a reference standard, to unify precipitation measurements from a constellation of other research and operational satellites. The NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC) hosts and distributes GPM data within the NASA Earth Observation System Data Information System (EOSDIS). The GES DISC is home to the data archive for the GPM predecessor, the Tropical Rainfall Measuring Mission (TRMM). Over the past 16 years, the GES DISC has served the scientific as well as other communities with TRMM data and user-friendly services. During the GPM era, the GES DISC will continue to provide user-friendly data services and customer support to users around the world. GPM products currently and to-be available include the following:Level-1 GPM Microwave Imager (GMI) and partner radiometer productsLevel-2 Goddard Profiling Algorithm (GPROF) GMI and partner productsLevel-3 daily and monthly productsIntegrated Multi-satellitE Retrievals for GPM (IMERG) products (early, late, and final) A dedicated Web portal (including user guides, etc.) has been developed for GPM data (http:disc.sci.gsfc.nasa.govgpm). Data services that are currently and to-be available include Google-like Mirador (http:mirador.gsfc.nasa.gov) for data search and access; data access through various Web services (e.g., OPeNDAP, GDS, WMS, WCS); conversion into various formats (e.g., netCDF, HDF, KML (for Google Earth), ASCII); exploration, visualization, and statistical online analysis through Giovanni (http:giovanni.gsfc.nasa.gov); generation of value-added products; parameter and spatial subsetting; time

  18. Post-depositional Diagenetic Carbonate Precipitation, Methane Production and Climate- Driven Sedimentary Processes in the Northeastern Pacific Nitinat Fan

    NASA Astrophysics Data System (ADS)

    Knudson, K. P.; Hendy, I. L.

    2008-12-01

    Ocean Drilling Program (ODP) Core 888B (48°10'N, 126°39'W), from the Nitinat Fan, Cascadia Margin is dominated by sediment deposited during glacial conditions and contains unconformities due to both non- deposition and turbidity current erosion. However, this core also displays a unique chemical signature indicative of post-depositional diagenetic CaCO3 precipitation due to CH4 oxidation. Climate history has been reconstructed based on core lithology, δ13C and δ18O of Globigerina bulloides, magnetic susceptibility, coiling ratios of Neogloboquadrina pachyderma, and 14C dates. The δ13C of marine carbonate, usually related to nutrient utilization, cannot account for the extremely negative G. bulloides δ13C at depths 110 mbsf (-6.5‰), 115 mbsf (-3.0‰), and 225 mbsf (-3.5‰). Instead, we posit that these spikes are a post-depositional diagenetic result of CaCO3 precipitation occurring where porewater alkalinity is rapidly changing due to CH4 oxidation. This secondary CaCO3 is strongly depleted in 12C due to the anaerobic oxidation of CH4 mediated by bacteria, which both favor the 12C isotope and consume CH4 with very negative δ13C. Finally, a telling correlation appears to exist between core lithology and CH4 peaks, leading us to conclude that the CH4 peaks and resulting diagenesis are thus a secondary consequence of climate- driven sedimentary processes. The first CH4 peak (93 ppmv; 78-113 mbsf) occurs within a sandy sediment facies containing wood fragments, possibly deposited during an early glacial period (Marine Isotope Stage 4), in which advancing ice carried terrigenous organic matter to the shelf edge. This wood matter then slowly decayed, consuming oxidants to the extent that methanogenesis occurred. The second CH4 peak (6863 ppmv; 185-240 mbsf), also correlated with a coarse sand facies, lacks evidence of terrigenous organic matter and thus may be related to lateral CH4 gas flow through the porous facies. Therefore, by providing coarse-grained and

  19. Comparison of NEXRAD Stage III and MPE precipitation products with constraints from high quality and density of raingauge networks in the Upper Guadalupe River Basin, Central Texas

    NASA Astrophysics Data System (ADS)

    Xie, H.; Wang, X.

    2006-05-01

    NEXRAD's Multisensor Precipitation Estimator (MPE) product replaced the Stage III product started in October 2003 at the West Gulf River Forecast Center (WGRFC) where includes most of the Texas and New Mexico. The MPE is an integrated product of rain gauge, NEXRAD, and satellite (GOES) precipitation estimates. The main objective of MPE is to reduce both areal-mean bias error and local bias error. The overall improved quality of MPE over Stage 3 is evident at the WGRFC. However, so far, there is no quantitative evaluation in a relative long period (one year or more) of a large area. In this study, high quality and density of 50 raingauge networks (6 minutes temporal resolution) in the Upper Guadalupe River Basin, Central Texas are used to evaluate both the Stage III (years 2001 and 2002) and MPE (year 2004) products. In this study, we propose two types of comparison (1) directly compare collocated radar cell and gauge of all rainfall events and (2) only compare collocated radar cell and gauge of homogeneous/uniform rainfall events. To find uniform rainfall events, 6-mintutes raingauge rainfall were used to calculate the correlation coefficient (CC) and coefficient of variation (CV) of a hour among one central gauge and its surrounding gauges (>= 4). For a particular rainfall hour, when CV is < 0.5 and CC is > 0.5, or CV is <0.1, the rainfall event of this hour is thus selected as a uniform or homogeneous rainfall event. Our preliminary results of CC from all rainfall events and homogeneous rainfall events for year 2004 (MPE) are 0.79 and 0.96, respectively. This indicates an overall good quality of MPE product in comparison with raingauge rainfall, especially for the homogeneous rainfall events. Work is in progress.

  20. Acidic precipitation

    SciTech Connect

    Martin, H.C.

    1987-01-01

    At the International Symposium on Acidic Precipitation, over 400 papers were presented, and nearly 200 of them are included here. They provide an overview of the present state of the art of acid rain research. The Conference focused on atmospheric science (monitoring, source-receptor relationships), aquatic effects (marine eutrophication, lake acidification, impacts on plant and fish populations), and terrestrial effects (forest decline, soil acidification, etc.).

  1. A simple and efficient purification platform for monoclonal antibody production based on chromatin-directed cell culture clarification integrated with precipitation and void-exclusion anion exchange chromatography.

    PubMed

    Chen, Quan; Abdul Latiff, Sarah Maria; Toh, Phyllicia; Peng, Xinying; Hoi, Aina; Xian, Mo; Zhang, Haibo; Nian, Rui; Zhang, Wei; Gagnon, Pete

    2016-10-20

    Protein A affinity chromatography, featured by its robustness and high-specificity, is still dominant as a first capture step for the purification of immunoglobulin G monoclonal antibodies (IgG mAbs). However, the material and operational costs of protein A are universally recognized as high, and its productivity is also limited as column mode. In order to overcome these limitations, industry is increasingly considering the use of non-protein A-based processes for IgG purification. In this study, sodium citrate precipitation (SCP) was developed as the primary purification step, and chromatin-directed cell culture clarification was demonstrated to significantly elevate the purification capability. Additional 0.05% (w/v) of Tween 20 was shown to effectively reduce the residual free antibody light chain (LC) during precipitation. The resuspended IgG was further polished by void-exclusion anion exchange chromatography (VEAX), which supported protein loading without buffer adjustment. The non-histone host cell protein (nh-HCP) content in the final product was about 5ppm and histone HCP below limit of detection (LOD). DNA was reduced to less than 1ppb, and aggregates/free LC less than 0.1%. The overall IgG recovery was 87.2%. A simple and efficient purification platform with only one-column step was therefore established, providing a more promising alternative to the current prevailing protein A-based purification platforms.

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

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

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

  3. The Global Precipitation Climatology Project (GPCP) combined precipitation dataset

    SciTech Connect

    Huffman, G.J.

    1997-01-01

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

  4. Trends of temperature and precipitation and their impact on grapewine phenology and production of in a Mediterranean vineyard region of Northeastern Spain

    NASA Astrophysics Data System (ADS)

    Ramos, M. C.; Jones, G. V.; Martínez-Casasnovas, J. A.

    2009-04-01

    The present analysis tries to contribute to the knowledge and impacts of climate change on agriculture, in particular in dryland areas of the Mediterranean NE Spain. The analysis was carried out in the Penedès region, located in Northeastern Spain (Barcelona province). In this area, vineyards have cultivated for centuries and at present represent about 80% of the cultivated area, most of them as rainfed agriculture, without irrigation. In order to analyse climate change impacts on grape development and production, the trends of daily rainfall and temperature were analyzed for the whole year and for the growing season, as well as some bioclimatic indexes (Hugling and Winkler index) using a long data set belonging to Vilafranca del Penedès for the period 1952-2006, and shorter series belonging to the observatories of Sant Sadurní d'Anoia, Sant Martí Sarroca, Els Hostalest de Pierola for the last 12 years (1996-2007). Phenology dates and production for the last 12 years for the main varieties cultivated in the area (Macabeo, Xarello, Parellada and Chardonnay) were analysed in relation to all the climatic analysed parameters. The study revealed warming trends with higher increases in the maximum temperatures (0.04°C/year) than in the minimum temperatures (0.03°C/year), and a significant increase in the number of days with temperatures higher than 30°C (0.43 days/year). Changes were also reproduced during the grape growing season. The increase of temperature has its influence on higher evapotranspiration ratios, which implies less effective water for crop development. Annual rainfall showed high variability from year to year and did not change significantly with time not at annual level either during the growing season. However, the precipitation of the main rainfall periods (spring and autumn) shows opposite trends, decreasing precipitation in spring and increasing in autumn. According to the vine phenological stages a significant decrease of precipitation

  5. Electrostatic Precipitator

    NASA Image and Video Library

    2017-06-09

    Dr. Carlos Calle, lead scientist in the Kennedy Space Center's Electrostatics and Surface Physics Laboratory, left, and Jay Phillips, a research physicist, are modifying an electrostatic precipitator to help remove dust from simulated Martian atmosphere. NASA's Journey to Mars requires cutting-edge technologies to solve the problems explorers will face on the Red Planet. Scientists are developing some of the needed solutions by adapting a device to remove the ever-present dust from valuable elements in the Martian atmosphere. Those commodities include oxygen, water and methane.

  6. Electrostatic Precipitator

    NASA Image and Video Library

    2017-06-09

    Dr. Carlos Calle, lead scientist in the Kennedy Space Center's Electrostatics and Surface Physics Laboratory, left, and Jay Phillips, a research physicist, are modifying an electrostatic precipitator to help remove dust from a simulated Martian atmosphere. NASA's Journey to Mars requires cutting-edge technologies to solve the problems explorers will face on the Red Planet. Scientists are developing some of the needed solutions by adapting a device to remove the ever-present dust from valuable elements in the Martian atmosphere. Those commodities include oxygen, water and methane.

  7. Electrostatic Precipitator

    NASA Image and Video Library

    2017-06-09

    Jay Phillips, a research physicist in the Kennedy Space Center's Electrostatics and Surface Physics Laboratory, left, and Dr. Carlos Calle, lead scientist in the lab, are modifying an electrostatic precipitator to help remove dust from simulated Martian atmosphere. NASA's Journey to Mars requires cutting-edge technologies to solve the problems explorers will face on the Red Planet. Scientists are developing some of the needed solutions by adapting a device to remove the ever-present dust from valuable elements in the Martian atmosphere. Those commodities include oxygen, water and methane.

  8. Generation of dose-response relationships to assess the effects of acidity in precipitation on growth and productivity of vegetation

    SciTech Connect

    Evans, L.S.

    1981-01-01

    Experiments were performed with several plant species in natural environments as well in a greenhouse and/or tissue culture facilities to establish dose-response functions of plant responses to simulated acidic rain in order to determine environmental risk assessments to ambient levels of acidic rain. Response functions of foliar injury, biomass of leaves and seed of soybean and pinto beans, root yields of radishes and garden beets, and reproduction of bracken fern are considered. The dose-response function of soybean seed yields with the hydrogen ion concentration of simulated acidic rainfalls was expressed by the equation y = 21.06-1.01 log x where y = seed yield in grams per plant and x = the hydrogen concentration if ..mu..eq l/sup -1/. The correlation coefficient of this relationship was -0.90. A similar dose-response function was generated for percent fertilization of ferns in a forest understory. When percent fertilization is plotted on logarithmic scale with hydrogen ion concentration of the simulated rain solution, the Y intercept is 51.18, slope -0.041 with a correlation coefficient of -0.98. Other dose-response functions were generated that assist in a general knowledge as to which plant species and which physiological processes are most impacted by acidic precipitation. Some responses did not produce convenient dose-response relationships. In such cases the responses may be altered by other environmental factors or there may be no differences among treatment means.

  9. An Ecoinformatic Analysis of the Effect of Seasonal and Annual Variation in Temperature, Precipitation, and Solar Irradiance on Pollen Productivity in Two Neotropical Forests

    NASA Astrophysics Data System (ADS)

    Haselhorst, D. S.; Tcheng, D. K.; Moreno, J. E.; Punyasena, S. W.

    2014-12-01

    Observational data provide a powerful source of information for understanding the phenological response of tropical forests to a changing climate. Annual changes in mean temperature, precipitation, and solar irradiance, in part driven by ENSO cycles, provide a natural experiment. However, these time series are often relatively short (several years to several decades), the average climatic variability experienced in that timeframe is relatively small, and the corresponding response is therefore often very weak. As a result, standard statistical approaches may fail in detecting a biological response. We present an alternative ecoinformatic analysis that demonstrates the power of weak models in the discovery and interpretation of statistically significant signals in short, noisy, ecological time series. We developed a simple response prediction model that uses cross-validation to explore a landscape of models that correlate the phenological behavior of individual taxa (pollen production, flowering, fruiting) to seasonal and annual mean temperature, precipitation, and solar irradiance using multivariate linear regression. We use a sign slope sensitivity analysis of each linear model that tallies positive and negative slope counts of a taxon's phenological behavior to our environmental and null variables. We applied this analysis to pollen trap data collected from 1996 to 2006 from two lowland Panamanian forests, Barro Colorado Island and Parque National San Lorenzo. We also tested the performance of our predictive model using published data of annual flowering and fruiting from BCI to corroborate that our approach could reproduce previously published results on tropical phenology. Our results indicate that although the overall variation in temperature was 3.28 °C over the ten year period, pollen productivity at both sites was most consistently affected by changes in temperature. This result was replicated by the published BCI flower and fruit data, which also

  10. Role of heterogeneous precipitation in determining the nature of products formed on oxidation of Fe(II) in seawater containing natural organic matter.

    PubMed

    Bligh, Mark W; Waite, T David

    2010-09-01

    A detailed kinetic model has been developed to describe the formation of the oxidation products, organically complexed Fe(III) and amorphous ferric oxide (AFO), on oxidation of Fe(II) in seawater containing Suwannee River fulvic acid (SRFA). Experimental data were collected using spectrophotometric detection of the Fe(III)-SRFA complex for a range of initial concentrations of Fe(II) and SRFA. Initial sensitivity analysis identified rate constants to which the model was most sensitive including those for heterogeneous precipitation of AFO and Fe(II)-SRFA formation and dissociation which to date have only been determined with a high degree of uncertainty. Using these rate constants as fitting parameters, an accurate fit to the experimental data could be obtained using a kinetic model describing key processes. However, reasonable fits could only be achieved with the inclusion of the heterogeneous precipitation reaction suggesting the importance of this reaction in determining the outcome of oxidation in the presence of organic ligands. The rate constants for Fe(II)-SRFA formation and dissociation were highly correlated and could not be determined uniquely, however their ratio revealed a stability constant of approximately 10(5), 3 orders of magnitude higher than previously reported. The fitted model also suggested that a complex interaction between Fe(II) and SRFA in the initial stages of the oxidation process determines the pathway of Fe(III)-SRFA formation.

  11. Recursive estimators of mean-areal and local bias in precipitation products that account for conditional bias

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Seo, Dong-Jun

    2017-03-01

    This paper presents novel formulations of Mean field bias (MFB) and local bias (LB) correction schemes that incorporate conditional bias (CB) penalty. These schemes are based on the operational MFB and LB algorithms in the National Weather Service (NWS) Multisensor Precipitation Estimator (MPE). By incorporating CB penalty in the cost function of exponential smoothers, we are able to derive augmented versions of recursive estimators of MFB and LB. Two extended versions of MFB algorithms are presented, one incorporating spatial variation of gauge locations only (MFB-L), and the second integrating both gauge locations and CB penalty (MFB-X). These two MFB schemes and the extended LB scheme (LB-X) are assessed relative to the original MFB and LB algorithms (referred to as MFB-O and LB-O, respectively) through a retrospective experiment over a radar domain in north-central Texas, and through a synthetic experiment over the Mid-Atlantic region. The outcome of the former experiment indicates that introducing the CB penalty to the MFB formulation leads to small, but consistent improvements in bias and CB, while its impacts on hourly correlation and Root Mean Square Error (RMSE) are mixed. Incorporating CB penalty in LB formulation tends to improve the RMSE at high rainfall thresholds, but its impacts on bias are also mixed. The synthetic experiment suggests that beneficial impacts are more conspicuous at low gauge density (9 per 58,000 km2), and tend to diminish at higher gauge density. The improvement at high rainfall intensity is partly an outcome of the conservativeness of the extended LB scheme. This conservativeness arises in part from the more frequent presence of negative eigenvalues in the extended covariance matrix which leads to no, or smaller incremental changes to the smoothed rainfall amounts.

  12. Production of a Pseudomonas lipase in n-alkane substrate and its isolation using an improved ammonium sulfate precipitation technique.

    PubMed

    Kanwar, Lambit; Gogoi, Binod Kumar; Goswami, Pranab

    2002-09-01

    Among the various lipidic and non-lipidic substances, normal alkanes within the chain lengths of C-12 to C-20 served as the best carbon substrates for the production of extracellular lipase by Pseudomonas species G6. Maximum lipase production of 25 U/ml of the culture broth was obtained by using n-hexadecane as the sole carbon substrate. The optimum pH of 8 and temperature of 34 + 1 degrees C were demonstrated for the production of lipase in n-hexadecane substrate. The optimum concentration of iron, which played a critical role on the lipase production, was found to be 0.25 mg/l. Lipase production could be enhanced to nearly 2.4-fold by using tributyrin at a concentration of 0.05% (v/v) in the culture medium. High recovery of the lipase protein (83%) from the culture broth was achieved by treating the culture supernatant with Silicone 21 Defoamer followed by ammonium sulfate (60% saturation) fractionation.

  13. Uncertainties in Arctic Precipitation

    NASA Astrophysics Data System (ADS)

    Majhi, I.; Alexeev, V. A.; Cherry, J. E.; Cohen, J. L.; Groisman, P. Y.

    2012-12-01

    Arctic precipitation is riddled with measurement biases; to address the problem is imperative. Our study focuses on comparison of various datasets and analyzing their biases for the region of Siberia and caution that is needed when using them. Five sources of data were used ranging from NOAA's product (RAW, Bogdanova's correction), Yang's correction technique and two reanalysis products (ERA-Interim and NCEP). The reanalysis dataset performed better for some months in comparison to Yang's product, which tends to overestimate precipitation, and the raw dataset, which tends to underestimate. The sources of bias vary from topography, to wind, to missing data .The final three products chosen show higher biases during the winter and spring season. Emphasis on equations which incorporate blizzards, blowing snow and higher wind speed is necessary for regions which are influenced by any or all of these factors; Bogdanova's correction technique is the most robust of all the datasets analyzed and gives the most reasonable results. One of our future goals is to analyze the impact of precipitation uncertainties on water budget analysis for the Siberian Rivers.

  14. On the Relationship between Observed NLDN Lightning Strikes and Modeled Convective Precipitation Rates Parameterization of Lightning NOx Production in CMAQ

    EPA Science Inventory

    Lightning-produced nitrogen oxides (NOX=NO+NO2) in the middle and upper troposphere play an essential role in the production of ozone (O3) and influence the oxidizing capacity of the troposphere. Despite much effort in both observing and modeling lightning NOX during the past dec...

  15. On the Relationship between Observed NLDN Lightning Strikes and Modeled Convective Precipitation Rates Parameterization of Lightning NOx Production in CMAQ

    EPA Science Inventory

    Lightning-produced nitrogen oxides (NOX=NO+NO2) in the middle and upper troposphere play an essential role in the production of ozone (O3) and influence the oxidizing capacity of the troposphere. Despite much effort in both observing and modeling lightning NOX during the past dec...

  16. Estimating the characteristics of extreme rainfall events using a suitable precipitation product in the Garhwal Himalaya in India

    NASA Astrophysics Data System (ADS)

    Ziegler, Alan D.; Bhardwaj, Alok; Wasson, Robert J.; Chow, Winston

    2017-04-01

    High intensity rainfall events during monsoon season causes huge damage to local people and economy in the Indian Himalaya. It is however, difficult to accurately estimate the magnitude and spatio-temporal variability of extreme rainfall because of the sparse and limited network of ground stations located within complex terrain of the Indian Himalaya, as well as the difficulty of maintaining the stations over time. Thus, secondary rainfall sources are important to hydrological and hazard studies, if they reproduce the dynamics of extreme rainfall satisfactorily. In this work, we evaluate four secondary products in the Garhwal Himalaya in India to estimate extreme rainfall, with a particular focus on the Mandakini Catchment, the site of devastating flood in 2013. The analysis included two satellite products: the TRMM and the PERSIANN, as well as two gridded products: the APHRODITE product and the IMD product. In comparing the four products against data collected at four ground stations, we determined that the IMD and TRMM products were superior to the others in detecting daily maximum monsoon rainfall. Additionally, the IMD product could document the daily extreme rainfall distribution during the June 2013 flood in the Mandakini Catchment and adjoining places better than the TRMM product. Based on these results, we selected the IMD gridded dataset with daily rainfall data from 1901 to 2013 to document the occurrence of extreme monsoon rainfall events in the Mandakini Catchment in the last century. We define extreme monsoon rainfall threshold as the 99th percentile of time series of rainfall values, and rainfall depth greater than 99th percentile is considered as extreme rainfall. The results show that extreme monsoon rainfall events occurred for 22 years out of 113 years of available data. The extreme events have increased since 2010 in the Mandakini Catchment including 4 events in 2010, 1 event in 2011, 2 events in 2012 and 3 events in 2013. Before 2010, two

  17. METHOD FOR REMOVING CONTAMINATION FROM PRECIPITATES

    DOEpatents

    Stahl, G.W.

    1959-01-01

    An improvement in the bismuth phosphate carrier precipitation process is presented for the recovery and purification of plutonium. When plutonium, in the tetravalent state, is carried on a bismuth phosphate precipitate, amounts of centain of the fission products are carried along with the plutonium. The improvement consists in washing such fission product contaminated preeipitates with an aqueous solution of ammonium hydrogen fluoride. since this solution has been found to be uniquely effective in washing fission production contamination from the bismuth phosphate precipitate.

  18. Evaluation of Precipitable Water Vapor from Four Satellite Products and Four Reanalysis Datasets against GPS Measurements on the Southern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Yang, K.; Pan, Z.; Qin, J.; Chen, D.

    2016-12-01

    Southern Tibetan Plateau (STP) is the pass of water vapor from South Asia into the Tibetan Plateau (TP), and the modeling accuracy of precipitable water vapor (PWV) in this region highly depends on water vapor advection estimation and land evaporation parameterization. Understanding its accuracy is important for assimilating PWV satellite products and improving hydrological cycle modeling in weather and climate models. In this study, PWV data from four satellite products (MODIS infrared and near-infrared measurements, AIRS Level-2 and Level-3) and four atmospheric reanalysis datasets (MERRA, JRA-55, NCEP-final, ERA-interim) are evaluated against ground-based GPS measurements at nine stations over the STP. Results show that the MODIS infrared water vapor is heavily underestimated by more than 20% (1.94mm), while the MODIS near-infrared water vapor is heavily overestimated by more than 35% (2.65mm) under clear-sky conditions. AIRS products have better performance than the MODIS and reanalysis data; especially, AIRS Level-2 product has lower bias (0.51mm), lower RMSE value (1.85mm) and higher correlation coefficients (R=0.90). So, the AIRS PWV has higher potential than the MODIS PWV to be used to establish high resolution and quality PWV datasets over the TP. The four reanalysis datasets exhibit similar performance in terms of correlation coefficient (R 0.88 0.91), mean bias (0.74 1.51 mm) and RMSE (2.2 2.36 mm); the ERA-interim has a slightly higher correlation (R=0.91) and the JRA-55 has a little lower bias ( 0.74 mm). The most important finding is that all the reanalyses have systematic positive biases along the PWV seasonal cycle, which is probably associated with the well-known wet bias for the TP in current climate models.

  19. Production of a novel bioflocculant MNXY1 by Klebsiella pneumoniae strain NY1 and application in precipitation of cyanobacteria and municipal wastewater treatment

    PubMed Central

    Nie, M.; Yin, X.; Jia, J.; Wang, Y.; Liu, S.; Shen, Q.; Li, P.; Wang, Z.

    2015-01-01

    Aims To isolate and characterize the novel bioflocculant-producing bacteria, to optimize the bioflocculant production and evaluate its potential applications. Methods and Results Klebsiella pneumoniae strain NY1, a bacterium that produces a novel bioflocculant (MNXY1), was selected on the chemically defined media. It was classified according to the 16S rRNA gene sequence, morphological and microscopic characteristics. MNXY1 was characterized to contain 26% protein and 66% total sugar. The constituent sugar monomers of MNXY1, revealed by NMR analysis, are glucose, galactose and quinovose. Favorable culture conditions for MNXY1 production were determined. Strain NY1 produces a high level (14.9 g l−1) of MNXY1. MNXY1 is thermostable and tolerant to the extreme pH. It precipitated 54% of cyanobacteria from laboratory culture and 72% of the total suspended solids from raw wastewater. Conclusions Strain NY1 was identified to produce a novel bioflocculant MNXY1. The outstanding performance of MNXY1 in practical applications and its availability in copious amounts make it attractive for further investigation and development for industrial scale applications. PMID:21679283

  20. Low molecular weight bioactive peptides derived from the enzymatic hydrolysis of collagen after isoelectric solubilization/precipitation process of turkey by-products.

    PubMed

    Khiari, Zied; Ndagijimana, Maurice; Betti, Mirko

    2014-09-01

    A process based on the isoelectric solubilization/precipitation (ISP) method was developed to recover collagen from low value poultry by-products. The application of the ISP process to turkey heads generated protein isolates and an insoluble biomass that was used to extract collagen. Isolated turkey head collagen was then enzymatically hydrolyzed for different time periods using alcalase, flavorzyme, and trypsin. The enzymatic hydrolysis approaches consisted of digesting collagen with each one of the 3 enzymes alone (alcalase, flavorzyme, or trypsin), or one of the 3 combinations of 2 enzymes (alcalase/flavorzyme, alcalase/trypsin, or flavorzyme/trypsin), or a cocktail of all 3 enzymes together (alcalase/flavorzyme/trypsin). The molecular weight distribution of turkey head collagen hydrolysates was determined using size exclusion chromatography and matrix-assisted laser desorption ionization-time of flight-mass spectrometry. The enzyme cocktail produced collagen hydrolysates with the greatest amount of low molecular weight peptides ranging from 555.26 to 2,093.74 Da. These collagen peptides showed excellent solubility over a wide pH range (2 -: 8) and were able to bind cholic and deoxycholic acids and significantly (P < 0.05) inhibited plasma amine oxidase in a dose- and time-dependent manner. The ISP process combined with enzyme cocktail hydrolysis represents a potential new way to produce low molecular weight bioactive collagen peptides from low value poultry by-products.

  1. Observation-Corrected Precipitation Estimates in GEOS-5

    NASA Technical Reports Server (NTRS)

    Reichle, Rolf H.; Liu, Qing

    2014-01-01

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

  2. Photocatalytic hydrogen production by water/methanol decomposition using Au/TiO2 prepared by deposition-precipitation with urea.

    PubMed

    Oros-Ruiz, Socorro; Zanella, Rodolfo; López, Rosendo; Hernández-Gordillo, Agileo; Gómez, Ricardo

    2013-12-15

    Gold nanoparticles deposited on TiO2 Degussa P25, prepared by deposition-precipitation with urea, were studied in the photocatalytic hydrogen production. The effect of parameters such as mass of catalyst, gold loading, thermal treatment, and atmosphere of treatment was evaluated and optimized. The presence of metallic gold on the titania surface showed to have contributed to the high improvement in the activity of bare TiO2 for hydrogen generation under UV light (λ=254 nm) using a lamp of low energy (2W) consumption. The optimal gold loading for the photocatalysts was 0.5 wt.%, the mass of catalyst in the reactor was 0.5 g/L in a water/methanol 1:1 vol. solution, and the thermal treatment that produced the most active gold nanoparticles was found at 300°C. The photocatalysts thermally treated under hydrogen at 300°C produced 1492 μmol g(-1)h(-1) of hydrogen; the same catalyst activated in air produced 1866 μmo lg(-1)h(-1) of hydrogen.

  3. Analysis of Multiple Precipitation Products and Preliminary Assessment of Their Impact on Global Land Data Assimilation System (GLDAS) Land Surface States

    NASA Technical Reports Server (NTRS)

    Gottschalck, Jon; Meng, Jesse; Rodel, Matt; Houser, paul

    2005-01-01

    Land surface models (LSMs) are computer programs, similar to weather and climate prediction models, which simulate the stocks and fluxes of water (including soil moisture, snow, evaporation, and runoff) and energy (including the temperature of and sensible heat released from the soil) after they arrive on the land surface as precipitation and sunlight. It is not currently possible to measure all of the variables of interest everywhere on Earth with sufficient accuracy and space-time resolution. Hence LSMs have been developed to integrate the available observations with our understanding of the physical processes involved, using powerful computers, in order to map these stocks and fluxes as they change in time. The maps are used to improve weather forecasts, support water resources and agricultural applications, and study the Earth's water cycle and climate variability. NASA's Global Land Data Assimilation System (GLDAS) project facilitates testing of several different LSMs with a variety of input datasets (e.g., precipitation, plant type). Precipitation is arguably the most important input to LSMs. Many precipitation datasets have been produced using satellite and rain gauge observations and weather forecast models. In this study, seven different global precipitation datasets were evaluated over the United States, where dense rain gauge networks contribute to reliable precipitation maps. We then used the seven datasets as inputs to GLDAS simulations, so that we could diagnose their impacts on output stocks and fluxes of water. In terms of totals, the Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) had the closest agreement with the US rain gauge dataset for all seasons except winter. The CMAP precipitation was also the most closely correlated in time with the rain gauge data during spring, fall, and winter, while the satellitebased estimates performed best in summer. The GLDAS simulations revealed that modeled soil moisture is highly

  4. Analysis of Multiple Precipitation Products and Preliminary Assessment of Their Impact on Global Land Data Assimilation System (GLDAS) Land Surface States

    NASA Technical Reports Server (NTRS)

    Gottschalck, Jon; Meng, Jesse; Rodel, Matt; Houser, paul

    2005-01-01

    Land surface models (LSMs) are computer programs, similar to weather and climate prediction models, which simulate the stocks and fluxes of water (including soil moisture, snow, evaporation, and runoff) and energy (including the temperature of and sensible heat released from the soil) after they arrive on the land surface as precipitation and sunlight. It is not currently possible to measure all of the variables of interest everywhere on Earth with sufficient accuracy and space-time resolution. Hence LSMs have been developed to integrate the available observations with our understanding of the physical processes involved, using powerful computers, in order to map these stocks and fluxes as they change in time. The maps are used to improve weather forecasts, support water resources and agricultural applications, and study the Earth's water cycle and climate variability. NASA's Global Land Data Assimilation System (GLDAS) project facilitates testing of several different LSMs with a variety of input datasets (e.g., precipitation, plant type). Precipitation is arguably the most important input to LSMs. Many precipitation datasets have been produced using satellite and rain gauge observations and weather forecast models. In this study, seven different global precipitation datasets were evaluated over the United States, where dense rain gauge networks contribute to reliable precipitation maps. We then used the seven datasets as inputs to GLDAS simulations, so that we could diagnose their impacts on output stocks and fluxes of water. In terms of totals, the Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) had the closest agreement with the US rain gauge dataset for all seasons except winter. The CMAP precipitation was also the most closely correlated in time with the rain gauge data during spring, fall, and winter, while the satellitebased estimates performed best in summer. The GLDAS simulations revealed that modeled soil moisture is highly

  5. Experimental Warming and Precipitation Effects on Plant Community Composition, Productivity, Nutrient Availability, and Soil Respiration in Pacific Northwest Prairies along a Natural Climate Gradient

    NASA Astrophysics Data System (ADS)

    Bridgham, S. D.; Pfeifer-Meister, L.; Tomaszewski, T.; Reynolds, L.; Goklany, M.; Wilson, H.; Johnson, B. R.

    2011-12-01

    Climate change effects on soil respiration and carbon stores in grasslands globally may have significant implications for future atmospheric carbon dioxide concentrations. Climate change may also may negatively impact native plant species and favor exotic species. We are experimentally increasing temperature by 3 degrees C and increasing precipitation by 25% above ambient in three upland prairie sites along a natural climate gradient from southwestern Oregon to central-western Washington to determine how future climate change will affect (i) plant community composition and the relative success of native versus introduced plant species and (ii) above- and belowground carbon and nutrient dynamics. Sixty plots (20 at each site) were restored by mowing, raking, and herbicide application followed by the sowing of the same 34 native grass and forb species in each plot. Differences in total cover, net primary productivity, and community composition were much greater among sites than among treatments within sites in both 2010--the establishment year, and 2011-the first full year of treatment. Strong successional dynamics occurred over the two years as competition intensified, but these were dependent on a site-treatment interaction, with lower native plant survival in heated plots because of competitive exclusion by exotic, invasive plants. A strong treatment - season interaction in canopy cover (as determined by canopy reflectance) also occurred, with heating causing greater cover during the wet season and lower cover during the dry season. This effect was strongest in the southernmost site which experiences earlier and more intense drought conditions. There were also strong site, treatment, and season interactions on nutrient availability as determined by cation-anion exchange resins. Heating increased nutrient availability in all but the northernmost site during the growing season, and that site also had much lower nutrient availability, but overall availability and

  6. PRECIPITATION OF PLUTONOUS PEROXIDE

    DOEpatents

    Barrick, J.G.; Manion, J.P.

    1961-08-15

    A precipitation process for recovering plutonium values contained in an aqueous solution is described. In the process for precipitating plutonium as plutonous peroxide, hydroxylamine or hydrazine is added to the plutoniumcontaining solution prior to the addition of peroxide to precipitate plutonium. The addition of hydroxylamine or hydrazine increases the amount of plutonium precipitated as plutonous peroxide. (AEC)

  7. DISSOLUTION OF PLUTONIUM CONTAINING CARRIER PRECIPITATE BY CARBONATE METATHESIS AND SEPARATION OF SULFIDE IMPURITIES THEREFROM BY SULFIDE PRECIPITATION

    DOEpatents

    Duffield, R.B.

    1959-07-14

    A process is described for recovering plutonium from foreign products wherein a carrier precipitate of lanthanum fluoride containing plutonium is obtained and includes the steps of dissolving the carrier precipitate in an alkali metal carbonate solution, adding a soluble sulfide, separating the sulfide precipitate, adding an alkali metal hydroxide, separating the resulting precipitate, washing, and dissolving in a strong acid.

  8. Microbial production of isotopically light iron(II) in a modern chemically precipitated sediment and implications for isotopic variations in ancient rocks

    USGS Publications Warehouse

    Tangalos, G.E.; Beard, B.L.; Johnson, C.M.; Alpers, C.N.; Shelobolina, E.S.; Xu, H.; Konishi, H.; Roden, E.E.

    2012-01-01

    The inventories and Fe isotope composition of aqueous Fe(II) and solid-phase Fe compounds were quantified in neutral-pH, chemically precipitated sediments downstream of the Iron Mountain acid mine drainage site in northern California, USA. The sediments contain high concentrations of amorphous Fe(III) oxyhydroxides [Fe(III)am] that allow dissimilatory iron reduction (DIR) to predominate over Fe–S interactions in Fe redox transformation, as indicated by the very low abundance of Cr(II)-extractable reduced inorganic sulfur compared with dilute HCl-extractable Fe. δ56Fe values for bulk HCl- and HF-extractable Fe were ≈ 0. These near-zero bulk δ56Fe values, together with the very low abundance of dissolved Fe in the overlying water column, suggest that the pyrite Fe source had near-zero δ56Fe values, and that complete oxidation of Fe(II) took place prior to deposition of the Fe(III) oxide-rich sediment. Sediment core analyses and incubation experiments demonstrated the production of millimolar quantities of isotopically light (δ56Fe ≈ -1.5 to -0.5‰) aqueous Fe(II) coupled to partial reduction of Fe(III)am by DIR. Trends in the Fe isotope composition of solid-associated Fe(II) and residual Fe(III)am are consistent with experiments with synthetic Fe(III) oxides, and collectively suggest an equilibrium Fe isotope fractionation between aqueous Fe(II) and Fe(III)am of approximately -2‰. These Fe(III) oxide-rich sediments provide a model for early diagenetic processes that are likely to have taken place in Archean and Paleoproterozoic marine sediments that served as precursors for banded iron formations. Our results suggest pathways whereby DIR could have led to the formation of large quantities of low-δ56Fe minerals during BIF genesis.

  9. Microbial production of isotopically light iron(II) in a modern chemically precipitated sediment and implications for isotopic variations in ancient rocks.

    PubMed

    Tangalos, G E; Beard, B L; Johnson, C M; Alpers, C N; Shelobolina, E S; Xu, H; Konishi, H; Roden, E E

    2010-06-01

    The inventories and Fe isotope composition of aqueous Fe(II) and solid-phase Fe compounds were quantified in neutral-pH, chemically precipitated sediments downstream of the Iron Mountain acid mine drainage site in northern California, USA. The sediments contain high concentrations of amorphous Fe(III) oxyhydroxides [Fe(III)(am)] that allow dissimilatory iron reduction (DIR) to predominate over Fe-S interactions in Fe redox transformation, as indicated by the very low abundance of Cr(II)-extractable reduced inorganic sulfur compared with dilute HCl-extractable Fe. delta(56)Fe values for bulk HCl- and HF-extractable Fe were approximately 0. These near-zero bulk delta(56)Fe values, together with the very low abundance of dissolved Fe in the overlying water column, suggest that the pyrite Fe source had near-zero delta(56)Fe values, and that complete oxidation of Fe(II) took place prior to deposition of the Fe(III) oxide-rich sediment. Sediment core analyses and incubation experiments demonstrated the production of millimolar quantities of isotopically light (delta(56)Fe approximately -1.5 to -0.5 per thousand) aqueous Fe(II) coupled to partial reduction of Fe(III)(am) by DIR. Trends in the Fe isotope composition of solid-associated Fe(II) and residual Fe(III)(am) are consistent with experiments with synthetic Fe(III) oxides, and collectively suggest an equilibrium Fe isotope fractionation between aqueous Fe(II) and Fe(III)(am) of approximately -2 per thousand. These Fe(III) oxide-rich sediments provide a model for early diagenetic processes that are likely to have taken place in Archean and Paleoproterozoic marine sediments that served as precursors for banded iron formations. Our results suggest pathways whereby DIR could have led to the formation of large quantities of low-delta(56)Fe minerals during BIF genesis.

  10. Estimating Global Precipitation for Science and Application

    NASA Technical Reports Server (NTRS)

    Huffman, George J.

    2013-01-01

    Over the past two decades there has been vigorous development in the satellite assets and the algorithms necessary to estimate precipitation around the globe. In particular the highly successful joint NASAJAXA Tropical Rainfall Measuring Mission (TRMM) and the upcoming Global Precipitation Measurement (GPM) mission, also joint between NASA and JAXA, have driven these issues. At the same time, the long-running Global Precipitation Climatology Project (GPCP) continues to extend a stable, climate-oriented view of global precipitation. This talk will provide an overview of these projects and the wider international community of precipitation datasets, sketch plans for next-generation products, and provide some examples of the best use for the different products. One key lesson learned is that different data sets are needed to address the variety of issues that need precipitation data, including detailed 3-D views of hurricanes, flash flood forecasting, drought analysis, and global change.

  11. Climatic Variability of Precipitation from the Seasonal Cycle to ENSO Using GPCP's Merged Data Product and SSM/I-Based Microwave Estimates

    NASA Technical Reports Server (NTRS)

    Curtis, Scott; Huffman, George; Nelkin, Eric

    1999-01-01

    Satellite estimates and gauge observations of precipitation are useful in understanding the water cycle, analyzing climatic variability, and validating climate models. The Global Precipitation Climatology Project (GPCP) released a community merged precipitation data set for the period July 1987 through the present, and has recently extended that data set back to 1986. One objective of this study is to use GPCP estimates to describe and quantify the seasonal variation of precipitation, with emphasis on the Asian summer monsoon. Another focus is the 1997-98 El Nino Southern Oscillation (ENSO) and associated extreme precipitation events. The summer monsoon tends to be drier than normal in El Nino ears. This was not observed for 1997 or 1998, while for 1997 the NCEP model produced the largest summer rain rates over India in years. This inconsistency will be examined. The average annual global precipitation rate is 2.7 mm day as estimated by GPCP, which is similar to values computed from long-term climatologies. From 30 deg N to 30 deg S the average precipitation rate is 2.7 mm day over land with a maximum in the annual cycle occurring in February-March, when the Amazon basin receives abundant rainfall. The average precipitation rate is 3.1 mm day over the tropical oceans, with a peak earlier in the season (November-December), corresponding with the transition from a strong Pacific Intertropical Convergence Zone (ITCZ) from June to November to a strong South Pacific Convergence Zone (SPCZ) from December to March. The seasonal evolution of C, C, the Asian summer monsoon stands out with rains in excess of 15 mm day off the coast of Burma in June. The GPROF pentad data also captures the onset of the tropical Pacific rainfall patterns associated with the 1997-98 ENSO. From February to October 1997 at least four rain-producing systems traveled from West to East in the equatorial corridor. A rapid transition from El Nino to La Nina conditions occurred in May-June 1998. GPCP

  12. Electrostatic Precipitator (ESP) TRAINING MANUAL

    EPA Science Inventory

    The manual assists engineers in using a computer program, the ESPVI 4.0W, that models all elements of an electrostatic precipitator (ESP). The program is a product of the Electric Power Research Institute and runs in the Windows environment. Once an ESP is accurately modeled, the...

  13. Electrostatic Precipitator (ESP) TRAINING MANUAL

    EPA Science Inventory

    The manual assists engineers in using a computer program, the ESPVI 4.0W, that models all elements of an electrostatic precipitator (ESP). The program is a product of the Electric Power Research Institute and runs in the Windows environment. Once an ESP is accurately modeled, the...

  14. Precipitation Climate Data Records

    NASA Astrophysics Data System (ADS)

    Nelson, B. R.; Prat, O.; Vasquez, L.

    2015-12-01

    Five precipitation CDRs are now or soon will be transitioned to NOAA's CDR program. These include the PERSIANN data set, which is a 30-year record of daily adjusted global precipitation based on retrievals from satellite microwave data using artificial neural networks. The AMSU-A/B/Hydrobundle is an 11-year record of precipitable water, cloud water, ice water, and other variables. CMORPH (the NOAA Climate Prediction Center Morphing Technique) is a 17-year record of daily and sub-daily adjusted global precipitation measured from passive microwave and infrared data at high spatial and temporal resolution. GPCP (the Global Precipitation Climatology Project) is an approximately 30-year record of monthly and pentad adjusted global precipitation and a 17-year record of daily adjusted global precipitation. The NEXRAD Reanalysis is a 10-year record of high resolution NEXRAD radar based adjusted CONUS-wide hourly and daily precipitation. This study provides an assessment of the existing and transitioned long term precipitation CDRs and includes the verification of the five precipitation CDRs using various methods including comparison with in-situ data sets and trend analysis. As all of the precipitation related CDRs are transitioned, long term analyses can be performed. Comparisons at varying scales (hourly, daily and longer) of the precipitation CDRs with in-situ data sets are provided as well as a first look at what could be an ensemble long term precipitation data record.

  15. Application of quantitative precipitation forecasting and precipitation ensemble prediction for hydrological forecasting

    NASA Astrophysics Data System (ADS)

    Tao, P.; Tie-Yuan, S.; Zhi-Yuan, Y.; Jun-Chao, W.

    2015-05-01

    The precipitation in the forecast period influences flood forecasting precision, due to the uncertainty of the input to the hydrological model. Taking the ZhangHe basin as the example, the research adopts the precipitation forecast and ensemble precipitation forecast product of the AREM model, uses the Xin Anjiang hydrological model, and tests the flood forecasts. The results show that the flood forecast result can be clearly improved when considering precipitation during the forecast period. Hydrological forecast based on Ensemble Precipitation prediction gives better hydrological forecast information, better satisfying the need for risk information for flood prevention and disaster reduction, and has broad development opportunities.

  16. Towards Quantitative Ocean Precipitation Validation

    NASA Astrophysics Data System (ADS)

    Klepp, C.; Bakan, S.; Andersson, A.

    2009-04-01

    A thorough knowledge of global ocean precipitation is an indispensable prerequisite for the understanding and successful modelling of the global climate system as it is an important component of the water cycle. However, reliable detection of quantitative precipitation over the global oceans, especially at high latitudes during the cold season remains a challenging task for remote sensing and model based estimates. Quantitative ship validation data using reliable instruments for measuring rain and snowfall hardly exist but are highly demanded for ground validation of such products. The satellite based HOAPS (Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data) climatology contains fields of precipitation, evaporation and the resulting freshwater flux along with 12 additional atmospheric parameters over the global ice-free ocean between 1987 and 2005. Except for the NOAA Pathfinder SST, all basic state variables are calculated from SSM/I passive microwave radiometer measurements. HOAPS contains three main data subsets that originate from one common pixel-level data source. Gridded 0.5 degree monthly, pentad and twice daily data products are freely available from www.hoaps.org. Especially for North Atlantic mid-latitude mix-phase precipitation, the HOAPS precipitation retrieval has been investigated in some depth. This analysis revealed that the HOAPS retrieval qualitatively well represents cyclonic and intense mesoscale precipitation in agreement with ship observations and Cloudsat data, while GPCP, ECMWF forecast, ERA-40 and regional model data miss mesoscale precipitation substantially. As the differences between the investigated data sets are already large under mix-phase precipitation conditions, further work is carried out on snowfall validation during the cold season at high-latitudes. A Norwegian Sea field campaign in winter 2005 was carried out using an optical disdrometer capable of measuring quantitative amounts of snowfall over the ocean

  17. Responses of switchgrass to precipitation changes: Nonlinear and asymmetric?

    USDA-ARS?s Scientific Manuscript database

    Background/Question/Methods: Climate changes, including chronic changes in precipitation amounts, will influence plant physiology, biomass and productivity, and soil respiration. However, such precipitation effects on switchgrass, a major bioenergy crop, have not been well investigated. Two preci...

  18. Depth-dependence and monthly variability of charophyte biomass production: consequences for the precipitation of calcium carbonate in a shallow Chara-lake.

    PubMed

    Pukacz, Andrzej; Pełechaty, Mariusz; Frankowski, Marcin

    2016-11-01

    The month-to-month variability of biomass and CaCO3 precipitation by dense charophyte beds was studied in a shallow Chara-lake at two depths, 1 and 3 m. Charophyte dry weights (d.w.), the percentage contribution of calcium carbonate to the dry weight and the precipitation of CaCO3 per 1 m(2) were analysed from May to October 2011. Physical-chemical parameters of water were also measured for the same sample locations. The mean dry weight and calcium carbonate precipitation were significantly higher at 1 m than at 3 m. The highest measured charophyte dry weight (exceeding 2000 g m(-2)) was noted at 1 m depth in September, and the highest CaCO3 content in the d.w. (exceeding 80 % of d.w.) was observed at 3 m depth in August. The highest CaCO3 precipitation per 1 m(2) exceeded 1695 g at 1 m depth in August. Significant differences in photosynthetically active radiation (PAR) were found between 1 and 3 m depths; there were no significant differences between depths for other water properties. At both sampling depths, there were distinct correlations between the d.w., CaCO3 content and precipitation and water properties. In addition to PAR, the water temperature and magnesium and calcium ion concentrations were among the most significant determinants of CaCO3 content and d.w. The results show that light availability seems to be the major factor in determining charophyte biomass in a typical, undisturbed Chara-lake. The study results are discussed in light of the role of charophyte vegetation in whole ecosystem functioning, with a particular focus on sedimentary processes and the biogeochemical cycle within the littoral zone.

  19. Evaluating the Influence of Surface and Precipitation Characteristics on TMI and GMI Precipitation Retrievals.

    NASA Astrophysics Data System (ADS)

    Carr, N.; Kirstetter, P.; Hong, Y.; Gourley, J. J.; Ferraro, R. R.; Kummerow, C. D.; Petersen, W. A.; Schwaller, M.; Wang, N. Y.

    2014-12-01

    To evaluate the influence of surface and precipitation characteristics on Passive microwave (PMW) precipitation retrievals, precipitation products obtained from both the TRMM Microwave Imager (TMI) and the GPM Microwave Imager (GMI) were evaluated relative to independent high-resolution reference precipitation products obtained using the NOAA/NSSL ground radar-based Multi-Radar Multi-Sensor (MRMS) system. Specifically the ability of each sensor to detect, classify, and quantify instantaneous surface precipitation at its native pixel resolution is examined and linked to surface and precipitation characteristics. Surface characteristics were derived optically using NASA's Moderate Resolution Imaging Spectroradiometer (MODIS). Precipitation mesoscale characteristics such as convective-stratiform classification and spatial structure were obtained from the high-resolution reference data. The quality of both PMW sensors' retrievals varied considerably with surface characteristics; both sensors displayed decreased detection and quantification statistics over sparsely vegetated and dry surfaces. Similarly, the quality of the precipitation retrievals was affected by precipitation characteristics and high relative errors were evident in isolated and small-scale precipitation events as well as in mixed stratiform-convective events. The error characteristics of the two sensors also differed in several significant aspects, namely TMI tended to overestimate precipitation relative to the reference, while GMI underestimated precipitation. The influence of the precipitation and surface characteristics was less evident in the more sophisticated GMI retrievals. An additional outcome of the study was the adaptation of the comparison framework between space and ground precipitation estimates to accommodate the new probabilistic features of the GPM-era PMW precipitation retrievals.

  20. Sulfate removal from waste chemicals by precipitation.

    PubMed

    Benatti, Cláudia Telles; Tavares, Célia Regina Granhen; Lenzi, Ervim

    2009-01-01

    Chemical oxidation using Fenton's reagent has proven to be a viable alternative to the oxidative destruction of organic pollutants in mixed waste chemicals, but the sulfate concentration in the treated liquor was still above the acceptable limits for effluent discharge. In this paper, the feasibility of sulfate removal from complex laboratory wastewaters using barium and calcium precipitation was investigated. The process was applied to different wastewater cases (two composite samples generated in different periods) in order to study the effect of the wastewater composition on the sulfate precipitation. The experiments were performed with raw and oxidized wastewater samples, and carried out according to the following steps: (1) evaluate the pH effect upon sulfate precipitation on raw wastewaters at pH range of 2-8; (2) conduct sulfate precipitation experiments on raw and oxidized wastewaters; and (3) characterize the precipitate yielded. At a concentration of 80 g L(-1), barium precipitation achieved a sulfate removal up to 61.4% while calcium precipitation provided over 99% sulfate removal in raw and oxidized wastewaters and for both samples. Calcium precipitation was chosen to be performed after Fenton's oxidation; hence this process configuration favors the production of higher quality precipitates. The results showed that, when dried at 105 degrees C, the precipitate is composed of hemidrate and anhydrous calcium sulfate ( approximately 99.8%) and trace metals ( approximately 0.2%: Fe, Cr, Mn, Co, Ag, Mg, K, Na), what makes it suitable for reuse in innumerous processes.

  1. Impacts of extreme precipitation and seasonal changes in precipitation on plants

    NASA Astrophysics Data System (ADS)

    Zeppel, M. J. B.; Wilks, J.; Lewis, J. D.

    2013-10-01

    The hydrological cycle is predicted to become more intense in future climates, with both larger precipitation events and longer times between events. Redistribution of precipitation may occur both within and across seasons, and the resulting wide fluctuations in soil water content may dramatically affect plants. Though these responses remain poorly understood, recent research in this emerging field suggests the effects of redistributed precipitation may differ from predictions based on previous drought studies. We review available studies on both extreme precipitation (redistribution within seasons) and seasonal changes in precipitation (redistribution across seasons) on grasslands and forests. Extreme precipitation differentially affected Aboveground Net Primary Productivity (ANPP), depending on whether extreme precipitation led to increased or decreased soil water content (SWC), which differed based on the current precipitation at the site. Specifically, studies to date reported that extreme precipitation decreased ANPP in mesic sites, but, conversely, increased ANPP in xeric sites, suggesting that plant available water is a key factor driving responses to extreme precipitation. Similarly, the effects of seasonal changes in precipitation on ANPP, phenology, and leaf and fruit development varied with the effect on SWC. Reductions in spring or summer generally had negative effects on plants, associated with reduced SWC, while subsequent reductions in autumn or winter had little effect on SWC or plants. Similarly, increased summer precipitation had a more dramatic impact on plants than winter increases in precipitation. The patterns of response suggest xeric biomes may respond positively to extreme precipitation, while comparatively mesic biomes may be more likely to be negatively affected. And, seasonal changes in precipitation during warm or dry seasons may have larger effects than changes during cool or wet seasons. Accordingly, responses to redistributed

  2. Global Precipitation Measurement (GPM) Mission: NASA Precipitation Processing System (PPS)

    NASA Technical Reports Server (NTRS)

    Stocker, Erich Franz

    2008-01-01

    NASA is contributing the precipitation measurement data system PPS to support the GPM mission. PPS will distribute all GPM data products including NASA s GMI data products freely and quickly. PPS is implementing no system mechanisms for restricting access to GPM data. PPS is implementing no system mechanisms for charging for GPM data products. PPS will provide a number of geographical and parameter subsetting features available to its users. The first implementation of PPS (called PPS--) will assume processing of TRMM data effective 1 June 2008. TRMM realtime data will be available via PPS- to all users requesting access

  3. Ionization of molecular hydrogen and stripping of oxygen atoms and ions in collisions of Oq++H2 (q = 0- 8): Data for secondary electron production from ion precipitation at Jupiter

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

    Energetic oxygen and sulfur ion precipitation into the atmosphere of Jupiter is thought to produce an X-ray aurora as well as to contribute to ionization, heating, and dissociation of the molecules of the atmosphere. At high energy, stripping of electrons from these ions by atmospheric gas molecules results in the production of high charge states throughout a portion of this passage through the atmosphere. Therefore, to enable modeling of the effects of secondary electrons produced by this ion precipitation, from either the solar wind or magnetospheric sources such as the Galilean moons, a large range of ionization and stripping data is calculated and tabulated here that otherwise is not available. The present data are for the abundant precipitating species, oxygen, colliding with the dominant upper atmosphere gas, molecular hydrogen, and cover the principal reaction channels leading to secondary electron production (single and double ionization, transfer ionization, and double capture followed by autoionization, and single and double stripping of electrons from the projectile). Since the ions possess initial energies at the upper atmosphere in the keV to MeV range, and are then slowed as they pass through the atmosphere, results are calculated for 1-2000 keV/u Oq++H2 (q =0-8). In addition to the total cross sections for ionization and stripping processes, models require the distribution in energy and angle of the ejected electrons, so cross sections differential in these parameters are also calculated. The data may be used to model the energy deposited by ion precipitation in Jupiter's atmosphere and thereby contribute to the elucidation of the ionosphere-atmosphere coupling.

  4. On the new GPCC gridded reference data sets of observed (daily) monthly land-surface precipitation since (1988) 1901 published in 2014 including an all seasons open source test product

    NASA Astrophysics Data System (ADS)

    Ziese, Markus; Andreas, Becker; Peter, Finger; Anja, Meyer-Christoffer; Kirstin, Schamm; Udo, Schneider

    2014-05-01

    Since 1989 the Global Precipitation Climatology Centre (GPCC) collects world-wide observational in-situ data from rain gauges in order to provide gridded high quality and resolution land surface precipitation analyses as mandated by WMO's World Climate Research Program and the Global Climate Observing System (GCOS). In doing so a thorough quality control (QC) is performed on the original data prior to its entrance into the ever growing GPCC data archive being the world-wide largest with monthly totals for more than 90000 stations. Since 2012 also daily data is processed and the archive already holds daily data for more than 30000 stations with the aim to reach at least the same scope as for monthly data, ultimately. All archived data stems from various sources, e.g. national meteorological and hydrological services and regional or global data collections and is thus stored in source specific slots, allowing cross-checks on redundant records and subsequent QC at different sophistication levels depending on the timeliness demand on each product. All data products are referenced by digital object identifiers (DOIs all starting with "10.5676/DWD_GPCC/") and thus published in public domain (ftp://ftp-anon.dwd.de/pub/data/gpcc/html/download_gate.html) for minimum 10 years per product and version. In 2014 the monthly Full Data Reanalysis and the Climatology product releases of December 2011 are due for update. As the new Climatology product is also used as background climatology for all other data products, the Monitoring Product shall be re-processed for all years since 1986. Moreover the First Guess Products (daily and monthly) will benefit from the improved climatology. Finally, GPCC will release its first Full Data Daily Reanalysis product comprising the land-surface precipitation for every day since 1 January 1988. It will be extended backward in course of GPCC's participation in the ERA_CLIM2 re-analysis project. The double to triple size of the GPCC data archive

  5. Global Precipitation Measurement

    NASA Technical Reports Server (NTRS)

    Hou, Arthur Y.; Skofronick-Jackson, Gail; Kummerow, Christian D.; Shepherd, James Marshall

    2008-01-01

    This chapter begins with a brief history and background of microwave precipitation sensors, with a discussion of the sensitivity of both passive and active instruments, to trace the evolution of satellite-based rainfall techniques from an era of inference to an era of physical measurement. Next, the highly successful Tropical Rainfall Measuring Mission will be described, followed by the goals and plans for the Global Precipitation Measurement (GPM) Mission and the status of precipitation retrieval algorithm development. The chapter concludes with a summary of the need for space-based precipitation measurement, current technological capabilities, near-term algorithm advancements and anticipated new sciences and societal benefits in the GPM era.

  6. Cerium oxalate precipitation

    SciTech Connect

    Chang, T.P.

    1987-02-01

    Cerium, a nonradioactive, common stand-in for plutonium in development work, has been used to simulate several plutonium precipitation processes at the Savannah River Laboratory. There are similarities between the plutonium trifluoride and the cerium oxalate precipitations in particle size and extent of plating, but not particle morphology. The equilibrium solubility, precipitation kinetics, particle size, extent of plating, and dissolution characteristics of cerium oxalate have been investigated. Interpretations of particle size and plating based on precipitation kinetics (i.e., nucleation and crystal growth) are presented. 16 refs., 7 figs., 6 tabs.

  7. IMPROVED PROCESS OF PLUTONIUM CARRIER PRECIPITATION

    DOEpatents

    Faris, B.F.

    1959-06-30

    This patent relates to an improvement in the bismuth phosphate process for separating and recovering plutonium from neutron irradiated uranium, resulting in improved decontamination even without the use of scavenging precipitates in the by-product precipitation step and subsequently more complete recovery of the plutonium in the product precipitation step. This improvement is achieved by addition of fluomolybdic acid, or a water soluble fluomolybdate, such as the ammonium, sodium, or potassium salt thereof, to the aqueous nitric acid solution containing tetravalent plutonium ions and contaminating fission products, so as to establish a fluomolybdate ion concentration of about 0.05 M. The solution is then treated to form the bismuth phosphate plutonium carrying precipitate.

  8. Measurement of precipitation using lysimeters

    NASA Astrophysics Data System (ADS)

    Fank, Johann; Klammler, Gernot

    2013-04-01

    Austria's alpine foothill aquifers contain important drinking water resources, but are also used intensively for agricultural production. These groundwater bodies are generally recharged by infiltrating precipitation. A sustainable water resources management of these aquifers requires quantifying real evapotranspiration (ET), groundwater recharge (GR), precipitation (P) and soil water storage change (ΔS). While GR and ΔS can be directly measured by weighable lysimeters and P by separate precipitation gauges, ET is determined by solving the climatic water balance ET = P GR ± ΔS. According to WMO (2008) measurement of rainfall is strongly influenced by precipitation gauge errors. Most significant errors result from wind loss, wetting loss, evaporation loss, and due to in- and out-splashing of water. Measuring errors can be reduced by a larger area of the measuring gaugés surface and positioning the collecting vessel at ground level. Modern weighable lysimeters commonly have a surface of 1 m², are integrated into their typical surroundings of vegetation cover (to avoid oasis effects) and allow scaling the mass change of monolithic soil columns in high measuring accuracy (0.01 mm water equivalent) and high temporal resolution. Thus, also precipitation can be quantified by measuring the positive mass changes of the lysimeter. According to Meissner et al. (2007) also dew, fog and rime can be determined by means of highly precise weighable lysimeters. Furthermore, measuring precipitation using lysimeters avoid common measuring errors (WMO 2008) at point scale. Though, this method implicates external effects (background noise, influence of vegetation and wind) which affect the mass time series. While the background noise of the weighing is rather well known and can be filtered out of the mass time series, the influence of wind, which blows through the vegetation and affects measured lysimeter mass, cannot be corrected easily since there is no clear relation between

  9. Regional Bias of Satellite Precipitation Estimates

    NASA Astrophysics Data System (ADS)

    Modrick, T. M.; Georgakakos, K. P.; Spencer, C. R.

    2012-12-01

    Satellite-based estimates of precipitation have improved the spatial availability of precipitation data particularly for regions with limited gauge networks due to limited accessibility or infrastructure. Understanding the quality and reliability of satellite precipitation estimates is important, especially when the estimates are utilitized for real-time hydrologic forecasting and for fast-responding phenomena. In partnership with the World Meteorological Organization (WMO), the U.S. Agency of International Development (USAID) and the National Ocean and Atmospheric Administration (NOAA), the Hydrologic Research Center has begun implementation of real-time flash flood warning systems for diverse regions around the world. As part of this effort, bias characteristics of satellite precipitation have been examined in these various regions, such includes portions of Southeastern Asia, Southeastern Europe, the Middle East, Central America, and the southern half of the African continent. The work has focused on the Global Hydro-Estimator (GHE) precipitation product from NOAA/NESDIS. These real-time systems utilize the GHE given low latency times of this product. This presentation focuses on the characterization of precipitation bias as compared to in-situ gauge records, and the regional variations or similarities. Additional analysis is currently underway considering regional bias for other satellite precipitation products (e.g., CMORPH) for comparison with the GHE results.

  10. ENSO Variations in Tropical Precipitation

    NASA Technical Reports Server (NTRS)

    Curtis, Scott; Adler, Robert

    2002-01-01

    TRMM was launched during the height of the 1997-98 El Nino and offered new insights into the evolution of precipitation during this event. The rapid decline of the El Nino in May 1998 was followed by a long lasting La Nina. Extreme wet and dry regions in the tropics during this El Nino/Southern Oscillation (ENSO) cycle will be compared with the previous 23 years using the Global Precipitation Climatology Project (GPCP) products. In particular, patterns of precipitation anomalies preceding El Nino will be examined. It has been shown that 30-60 day oscillations in convection appear in the western Pacific before the onset of El Nino. Also, a fast traveling equatorial wave of rainfall circled the globe during the demise of 1997-98 El Nino. Recent work has revealed an interesting relationship between a gradient of anomalous precipitation in the eastern Indian Ocean and the initiation of El Nino. This link will be explored as well as other anomaly patterns in 2002, which may signal an upcoming El Nino.

  11. Experimental study of brushite precipitation

    NASA Astrophysics Data System (ADS)

    Arifuzzaman, S. M.; Rohani, S.

    2004-07-01

    A systematic approach was developed for the synthesis of orthophosphates in the laboratory. A set of experiments was designed to investigate the influence of initial calcium and phosphorus concentration on the precipitated phase, nucleation pH and product size distribution at 25°C. Another goal was to characterize the precipitated phase. The investigation was conducted in a batch reactor. The initial molar concentration of calcium chloride and hydrated sodium phosphate solutions was varied from 0.005 to 0.08-mole dm -3 and the solution pH was kept under 7.1. Analysis by powder XRD, FTIR and elemental P/Ca revealed that the crystals precipitated were pure brushite (dicalcium phosphate dihydrate), as expected, except in one experiment in which amorphous calcium phosphate precipitated. The brushite crystals produced had plate-like morphology as investigated by scanning electron microscopy (SEM). The nucleation pH showed a decreasing trend as the concentration of the calcium and phosphorus increased in the reactor, but the volume mean diameter of the crystals and the span of the crystal size distribution did not show any sensitivity to the changes in the initial calcium and phosphorus concentration.

  12. Nutrient removal and energy production in a urine treatment process using magnesium ammonium phosphate precipitation and a microbial fuel cell technique.

    PubMed

    Zang, Guo-Long; Sheng, Guo-Ping; Li, Wen-Wei; Tong, Zhong-Hua; Zeng, Raymond J; Shi, Chen; Yu, Han-Qing

    2012-02-14

    Urine pretreatment has attracted increasing interest as it is able to relieve the nitrogen and phosphorus overloading problems in municipal wastewater treatment plants. In this study, an integrated process, which combines magnesium ammonium phosphate (MAP) precipitation with a microbial fuel cell (MFC), is proposed for the recovery of a slow-release fertilizer and electricity from urine. In such a two-step process, both nitrogen and phosphorus are recovered through the MAP process, and organic matters in the urine are converted into electricity in the MFCs. With this integrated process, when the phosphorus recovery is maximized without a dose of PO(4)(3-)-P in the MAP precipitation process, removal efficiencies for PO(4)(3)-P and NH(4)(+)-N of 94.6% and 28.6%, respectively, were achieved with a chemical oxygen demand (COD) of 64.9% accompanied by a power output of 2.6 W m(-3). Whereas removal efficiencies for PO(4)(3)-P and NH(4)(+)-N of 42.6% and 40%, respectively, and a COD of 62.4% and power density of 0.9 W m(-3) were obtained if simultaneous recovery of phosphorus and nitrogen was required through dosing with 620 mg L(-1) of PO(4)(3-)-P in the MAP process. This work provides a new sustainable approach for the efficient and cost-effective treatment of urine with the recovery of energy and resources.

  13. PRECIPITATION OF PROTACTINIUM

    DOEpatents

    Moore, R.L.

    1958-07-15

    An lmprovement in the separation of protactinium from aqueous nitric acid solutions is described. 1t covers the use of lead dioxide and tin dioxide as carrier precipitates for the protactinium. In carrying out the process, divalent lead or divalent tin is addcd to the solution and oxidized, causing formation of a carrier precipitate of lead dioxide or stannic oxide, respectively.

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

    NASA Astrophysics Data System (ADS)

    Roman, J.

    2015-12-01

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

  15. Comparison of organic combustion products in fly ash collected by a venturi wet scrubber and an electrostatic precipitator at a coal-fired power station

    SciTech Connect

    Harrison, F.L.

    1985-02-01

    Organic compounds recovered from fly ash collected by an electrostatic precipitator (ESP) and a venturi wet scrubber (WS) at a coal-fired power station were analysed. Organic constituents in extracts of solid waste included large numbers of aliphatic and aromatic compounds. A series of normal C/sub 15/-C/sub 30/ paraffins was found in the aliphatic fractions. The aromatic compounds were of 1,2,3 and 4 rings. Polynuclear aromatic hydrocarbons containing more than 4 rings were shown to be poorly recovered. Comparison of organic constituents in extracts of fly ash from the WS and the ESP showed that ESP extracts contained more compounds in greater quantities. The types and quantities of organic compounds recovered are not expected to present any environmental hazard.

  16. Catalyzed precipitation in aluminum

    NASA Astrophysics Data System (ADS)

    Mitlin, David

    The work reported in Chapter 1 concerned the influence of Si on the precipitation of theta' (metastable Al2Cu) during the isothermal aging of Al-2Cu-1Si (wt. %). The binary alloys Al-2Cu and Al-1Si were studied for comparison. Only two precipitate phases were detected: pure Si in Al-Si and Al-Cu-Si, and theta' (metastable Al 2Cu) in Al-Cu and Al-Cu-Si. On aging the ternary, Si precipitates first, and provides heterogeneous sites to nucleate theta'. As a consequence, the density of theta' precipitates in Al-Cu-Si is much higher than in the binary Al-Cu. Also, the theta ' precipitates in the ternary alloy have lower aspect ratio (at given particle size) and lose coherence on their broad faces at a slower rate. The principal focus of Chapter 2 is to explain precipitation in Al-lat.%Si-lat%Ge. The microstructure is characterized using conventional and high resolution transmission electron microscopy, as well as energy dispersive X-ray spectroscopy. The first precipitates to come out of solid solution have a cube-cube orientation relationship with the matrix. High resolution TEM demonstrated that all the precipitates start out, and remain multiply twinned throughout the aging treatment. There is a variation in the stoichiometry of the precipitates, with the mean composition being Si-44.5at%Ge. It is also shown that in Al-Si-Ge it is not possible to achieve satisfactory hardness through a conventional heat treatment. This result is explained in terms of sluggish precipitation of the diamond-cubic Si-Ge phase coupled with particle coarsening. The purpose of Chapters 3 and 4 is to explain these properties in terms of the role that the Si-Ge additions have on modifying the conventional Al-Cu aging sequence. In both AlCu and AlCuSiGe the room temperature microstructure consists of both GP zones and theta″ precipitates. Upon aging at 190°C Al-Cu displays the well known precipitation sequence; the slow dissolution of GP zones and theta″ and the gradual formation of theta

  17. Using total precipitable water anomaly as a forecast aid for heavy precipitation events

    NASA Astrophysics Data System (ADS)

    VandenBoogart, Lance M.

    Heavy precipitation events are of interest to weather forecasters, local government officials, and the Department of Defense. These events can cause flooding which endangers lives and property. Military concerns include decreased trafficability for military vehicles, which hinders both war- and peace-time missions. Even in data-rich areas such as the United States, it is difficult to determine when and where a heavy precipitation event will occur. The challenges are compounded in data-denied regions. The hypothesis that total precipitable water anomaly (TPWA) will be positive and increasing preceding heavy precipitation events is tested in order to establish an understanding of TPWA evolution. Results are then used to create a precipitation forecast aid. The operational, 16 km-gridded, 6-hourly TPWA product developed at the Cooperative Institute for Research in the Atmosphere (CIRA) compares a blended TPW product with a TPW climatology to give a percent of normal TPWA value. TPWA evolution is examined for 84 heavy precipitation events which occurred between August 2010 and November 2011. An algorithm which uses various TPWA thresholds derived from the 84 events is then developed and tested using dichotomous contingency table verification statistics to determine the extent to which satellite-based TPWA might be used to aid in forecasting precipitation over mesoscale domains. The hypothesis of positive and increasing TPWA preceding heavy precipitation events is supported by the analysis. Event-average TPWA rises for 36 hours and peaks at 154% of normal at the event time. The average precipitation event detected by the forecast algorithm is not of sufficient magnitude to be termed a "heavy" precipitation event; however, the algorithm adds skill to a climatological precipitation forecast. Probability of detection is low and false alarm ratios are large, thus qualifying the algorithm's current use as an aid rather than a deterministic forecast tool. The algorithm

  18. Precipitation patterns during channel flow

    NASA Astrophysics Data System (ADS)

    Jamtveit, B.; Hawkins, C.; Benning, L. G.; Meier, D.; Hammer, O.; Angheluta, L.

    2013-12-01

    Mineral precipitation during channelized fluid flow is widespread in a wide variety of geological systems. It is also a common and costly phenomenon in many industrial processes that involve fluid flow in pipelines. It is often referred to as scale formation and encountered in a large number of industries, including paper production, chemical manufacturing, cement operations, food processing, as well as non-renewable (i.e. oil and gas) and renewable (i.e. geothermal) energy production. We have studied the incipient stages of growth of amorphous silica on steel plates emplaced into the central areas of the ca. 1 meter in diameter sized pipelines used at the hydrothermal power plant at Hellisheidi, Iceland (with a capacity of ca 300 MW electricity and 100 MW hot water). Silica precipitation takes place over a period of ca. 2 months at approximately 120°C and a flow rate around 1 m/s. The growth produces asymmetric ca. 1mm high dendritic structures ';leaning' towards the incoming fluid flow. A novel phase-field model combined with the lattice Boltzmann method is introduced to study how the growth morphologies vary under different hydrodynamic conditions, including non-laminar systems with turbulent mixing. The model accurately predicts the observed morphologies and is directly relevant for understanding the more general problem of precipitation influenced by turbulent mixing during flow in channels with rough walls and even for porous flow. Reference: Hawkins, C., Angheluta, L., Hammer, Ø., and Jamtveit, B., Precipitation dendrites in channel flow. Europhysics Letters, 102, 54001

  19. Precipitation Estimates for Hydroelectricity

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  20. My NASA Data Precipitation

    NASA Image and Video Library

    This lesson has two activities that help students develop a basic understanding of the relationship between cloud type and the form of precipitation and the relationship between the amount of water...

  1. IMERG Global Precipitation Rates

    NASA Image and Video Library

    NASA's Global Precipitation Measurement mission has produced its first global map of rainfall and snowfall. The GPM Core Observatory launched one year ago on Feb. 27, 2014 as a collaboration betwee...

  2. Chemisorption And Precipitation Reactions

    EPA Science Inventory

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

  3. Chemisorption And Precipitation Reactions

    EPA Science Inventory

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

  4. Precipitation Estimates for Hydroelectricity

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  5. Widespread Occurrence of Glyphosate and its Degradation Product (AMPA) in U.S. Soils, Surface Water, Groundwater, and Precipitation, 2001-2009

    NASA Astrophysics Data System (ADS)

    Brauman, K. A.; Flörke, M.; Mueller, N. D.; Foley, J. A.

    2011-12-01

    Water is integral to agricultural production, and agriculture is by far the largest human use of water, so food security and water sustainability are inexorably linked. When water goes to food production, however, the benefits and costs are not uniformly distributed across the globe. We quantify the magnitude and global range of the multidimensional tradeoffs among food production, water consumption, and water quality impairment. To evaluate the productivity of water consumption in agriculture, we quantified the magnitude and global range of crop water productivity, the amount of food produced per unit of water consumed, for 16 major food crops (Brauman et al., 2013). We now expand on this, contextualizing the impact of high or low water productivity with information about water availability. Using outputs from the WaterGAP3 model (Flörke et al., 2013, Verzano et al. 2012), we map the burden of agricultural water consumption on total water availability. To incorporate impacts of agriculture on water quality, we include areas of excess nutrient application (Mueller et al., 2012). The integrated information about yield, water consumption, water availability, and nutrient application shows that benefits and impacts to water quantity and quality are not evenly distributed. Analogous to previous investigations of 'yield gaps,' which identified areas where biophysical conditions are sufficient for achieving yields higher than those that are attained (Licker et al., 2010), we show that in many places, for the given impacts to water, food production could be increased.

  6. Global Precipitation Measurement (GPM) Mission Products and Services at the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC)

    NASA Technical Reports Server (NTRS)

    Liu, Z.; Ostrenga, D.; Vollmer, B.; Kempler, S.; Deshong, B.; Greene, M.

    2015-01-01

    The NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC) hosts and distributes GPM data within the NASA Earth Observation System Data Information System (EOSDIS). The GES DISC is also home to the data archive for the GPM predecessor, the Tropical Rainfall Measuring Mission (TRMM). Over the past 17 years, the GES DISC has served the scientific as well as other communities with TRMM data and user-friendly services. During the GPM era, the GES DISC will continue to provide user-friendly data services and customer support to users around the world. GPM products currently and to-be available: -Level-1 GPM Microwave Imager (GMI) and partner radiometer products, DPR products -Level-2 Goddard Profiling Algorithm (GPROF) GMI and partner products, DPR products -Level-3 daily and monthly products, DPR products -Integrated Multi-satellitE Retrievals for GPM (IMERG) products (early, late, and final) A dedicated Web portal (including user guides, etc.) has been developed for GPM data (http://disc.sci.gsfc.nasa.gov/gpm). Data services that are currently and to-be available include Google-like Mirador (http://mirador.gsfc.nasa.gov/) for data search and access; data access through various Web services (e.g., OPeNDAP, GDS, WMS, WCS); conversion into various formats (e.g., netCDF, HDF, KML (for Google Earth), ASCII); exploration, visualization, and statistical online analysis through Giovanni (http://giovanni.gsfc.nasa.gov); generation of value-added products; parameter and spatial subsetting; time aggregation; regridding; data version control and provenance; documentation; science support for proper data usage, FAQ, help desk; monitoring services (e.g. Current Conditions) for applications. The United User Interface (UUI) is the next step in the evolution of the GES DISC web site. It attempts to provide seamless access to data, information and services through a single interface without sending the user to different applications or URLs (e.g., search, access

  7. Status of High Latitude Precipitation Estimates from Observations and Reanalyses

    NASA Technical Reports Server (NTRS)

    Behrangi, Ali; Christensen, Matthew; Richardson, Mark; Lebsock, Matthew; Stephens, Graeme; Huffman, George J.; Bolvin, David T.; Adler, Robert F.; Gardner, Alex; Lambrigtsen, Bjorn H.; hide

    2016-01-01

    An intercomparison of high-latitude precipitation characteristics from observation-based and reanalysis products is performed. In particular, the precipitation products from CloudSat provide an independent assessment to other widely used products, these being the observationally based Global Precipitation Climatology Project (GPCP), Global Precipitation Climatology Centre, and Climate Prediction Center Merged Analysis of Precipitation (CMAP) products and the ERA-Interim, Modern-Era Retrospective Analysis for Research and Applications (MERRA), and National Centers for Environmental Prediction-Department of Energy Reanalysis 2 (NCEP-DOE R2) reanalyses. Seasonal and annual total precipitation in both hemispheres poleward of 55 latitude are considered in all products, and CloudSat is used to assess intensity and frequency of precipitation occurrence by phase, defined as rain, snow, or mixed phase. Furthermore, an independent estimate of snow accumulation during the cold season was calculated from the Gravity Recovery and Climate Experiment. The intercomparison is performed for the 20072010 period when CloudSat was fully operational. It is found that ERA-Interim and MERRA are broadly similar, agreeing more closely with CloudSat over oceans. ERA-Interim also agrees well with CloudSat estimates of snowfall over Antarctica where total snowfall from GPCP and CloudSat is almost identical. A number of disagreements on regional or seasonal scales are identified: CMAP reports much lower ocean precipitation relative to other products, NCEP-DOE R2 reports much higher summer precipitation over Northern Hemisphere land, GPCP reports much higher snowfall over Eurasia, and CloudSat overestimates precipitation over Greenland, likely due to mischaracterization of rain and mixed-phase precipitation. These outliers are likely unrealistic for these specific regions and time periods. These estimates from observations and reanalyses provide useful insights for diagnostic assessment of

  8. Global Precipitation Mission Visualization Tool

    NASA Technical Reports Server (NTRS)

    Schwaller, Mathew

    2011-01-01

    The Global Precipitation Mission (GPM) software provides graphic visualization tools that enable easy comparison of ground- and space-based radar observations. It was initially designed to compare ground radar reflectivity from operational, ground-based, S- and C-band meteorological radars with comparable measurements from the Tropical Rainfall Measuring Mission (TRMM) satellite's precipitation radar instrument. This design is also applicable to other groundbased and space-based radars, and allows both ground- and space-based radar data to be compared for validation purposes. The tool creates an operational system that routinely performs several steps. It ingests satellite radar data (precipitation radar data from TRMM) and groundbased meteorological radar data from a number of sources. Principally, the ground radar data comes from national networks of weather radars (see figure). The data ingested by the visualization tool must conform to the data formats used in GPM Validation Network Geometry-matched data product generation. The software also performs match-ups of the radar volume data for the ground- and space-based data, as well as statistical and graphical analysis (including two-dimensional graphical displays) on the match-up data. The visualization tool software is written in IDL, and can be operated either in the IDL development environment or as a stand-alone executable function.

  9. Satellite derived precipitation mapping using GIS technology

    NASA Astrophysics Data System (ADS)

    Dyras, Izabela

    2005-10-01

    The paper presents the GIS technology application allowing mapping the precipitation from the microwave satellite data. The analysis results are prepared in the form of maps of precipitation intensity and range from an Advanced Microwave Sounding Unit (AMSU) on board of NOAA (15-17) satellites. The products such as Rain Rate (RR), Scattering Index (SI), Total Precipitation Water (TPW), Precipitation Probability (PP) and Liquid Water Path (LWP) were prepared basing on the regression algorithms. Surface data are converted into thematic coverages, too. The developed system allows displaying the precipitation observed with the satellite data and other ancillary information. Satellite and lightning data layers were also introduced to the system. Such approach allows presentation and analysis of the data coming from the various sources and enables validating the methods for the precipitation algorithms from microwave data. The problems related to the data specific spatial, temporal resolution and variability are presented and discussed. The maps of precipitation with additional geographical data and administrative boundaries are available for the weather forecasting units via Intranet. It is planned to make images available on the web for internal and external customers using web map server.

  10. The Global Precipitation Measurement (GPM) Project

    NASA Technical Reports Server (NTRS)

    Azarbarzin, Ardeshir; Carlisle, Candace

    2010-01-01

    The Global Precipitation Measurement (GP!v1) mission is an international cooperative effort to advance the understanding of the physics of the Earth's water and energy cycle. Accurate and timely knowledge of global precipitation is essential for understanding the weather/climate/ecological system, for improving our ability to manage freshwater resources, and for predicting high-impact natural hazard events including floods, droughts, extreme weather events, and landslides. The GPM Core Observatory will be a reference standard to uniformly calibrate data from a constellation of spacecraft with passive microwave sensors. GPM is being developed under a partnership between the United States (US) National Aeronautics and Space Administration (NASA) and the Japanese Aerospace and Exploration Agency (JAXA). NASA's Goddard Space Flight Center (GSFC), in Greenbelt, MD is developing the Core Observatory, two GPM Microwave Imager (GMI) instruments, Ground Validation System and Precipitation Processing System for the GPM mission. JAXA will provide a Dual-frequency Precipitation Radar (DPR) for installation on the Core satellite and launch services for the Core Observatory. The second GMI instrument will be flown on a partner-provided spacecraft. Other US agencies and international partners contribute to the GPM mission by providing precipitation measurements obtained from their own spacecraft and/or providing ground-based precipitation measurements to support ground validation activities. The Precipitation Processing System will provide standard data products for the mission.

  11. Distribution of soluble and precipitated iron and chromium products generated by anodic dissolution of 316L stainless steel and alloy C-22: final report

    SciTech Connect

    Estill, J; Farmer, J; Gordon, S; King, K; Logotetta, L; Silberman, D

    1999-08-11

    At near neutral pH and at applied potentials above the threshold potential for localized breakdown of the passive film, virtually all of the dissolved chromium appeared to be in the hexavalent oxidation state (Cr(VI)). In acidic environments, such as crevice solutions formed during the crevice corrosion of 316L and C-22 samples in 4 M NaCl, virtually all of the dissolved chromium appeared to be in the trivalent oxidation state (Cr(III)). These general observations appear to be consistent with the Pourbaix diagram for chromium (Pourbaix 1974), pp. 307-321. At high pH and high anodic polarization (pH {approximately} 8 and 800 mV vs. SHE), the predominate species is believed to be the soluble chromate anion (CrO{sub 4}{sup 2{minus}}). At the same pH, but lower polarization (pH {approximately} 8 and 0 mV vs. SHE), the predominate species are believed to be precipitates such as trivalent Cr(OH){sub 3} {center_dot} n(H{sub 2}O) and hexavalent Cr{sub 2}O{sub 3}. In acidified environments such as those found in crevices (pH < 3), soluble Cr{sup 3+} is expected to form over a wide range of potential extending from 400 mV vs. SHE to approximately 1200 mV vs. SHE. Again, this is consistent with the observations from the creviced samples. In earlier studies by the principal investigator, it has been found that low-level chromium contamination in ground water is usually in the hexavalent oxidation state (Farmer et al. 1996). In general, dissolved iron measured during the crevice experiments appears to be Fe(II) in acidic media and Fe(III) in near-neutral and alkaline solutions (table 3). In the case of cyclic polarization measurements, the dissolved iron measured at the end of some cyclic polarization measurements with C-22 appeared to be in the Fe(III) state. This is probably due to the high electrochemical potential at which these species were generated during the potential scan. Note that the reversal potential was approximately 1200 mV vs. Ag/AgCl during these scans. These

  12. Multiresolution comparison of precipitation datasets for large-scale models

    NASA Astrophysics Data System (ADS)

    Chun, K. P.; Sapriza Azuri, G.; Davison, B.; DeBeer, C. M.; Wheater, H. S.

    2014-12-01

    Gridded precipitation datasets are crucial for driving large-scale models which are related to weather forecast and climate research. However, the quality of precipitation products is usually validated individually. Comparisons between gridded precipitation products along with ground observations provide another avenue for investigating how the precipitation uncertainty would affect the performance of large-scale models. In this study, using data from a set of precipitation gauges over British Columbia and Alberta, we evaluate several widely used North America gridded products including the Canadian Gridded Precipitation Anomalies (CANGRD), the National Center for Environmental Prediction (NCEP) reanalysis, the Water and Global Change (WATCH) project, the thin plate spline smoothing algorithms (ANUSPLIN) and Canadian Precipitation Analysis (CaPA). Based on verification criteria for various temporal and spatial scales, results provide an assessment of possible applications for various precipitation datasets. For long-term climate variation studies (~100 years), CANGRD, NCEP, WATCH and ANUSPLIN have different comparative advantages in terms of their resolution and accuracy. For synoptic and mesoscale precipitation patterns, CaPA provides appealing performance of spatial coherence. In addition to the products comparison, various downscaling methods are also surveyed to explore new verification and bias-reduction methods for improving gridded precipitation outputs for large-scale models.

  13. Precipitation of metal nitrides from chloride melts

    SciTech Connect

    Slater, S.A.; Miller, W.E.; Willit, J.L.

    1996-12-31

    Precipitation of actinides, lanthanides, and fission products as nitrides from molten chloride melts is being investigated for use as a final cleanup step in treating radioactive salt wastes generated by electrometallurgical processing of spent nuclear fuel. The radioactive components (eg, fission products) need to be removed to reduce the volume of high-level waste that requires disposal. To extract the fission products from the salt, a nitride precipitation process is being developed. The salt waste is first contacted with a molten metal; after equilibrium is reached, a nitride is added to the metal phase. The insoluble nitrides can be recovered and converted to a borosilicate glass after air oxidation. For a bench-scale experimental setup, a crucible was designed to contact the salt and metal phases. Solubility tests were performed with candidate nitrides and metal nitrides for which there are no solubility data. Experiments were performed to assess feasibility of precipitation of metal nitrides from chloride melts.

  14. Correcting satellite-based precipitation products through SMOS soil moisture data assimilation in two land-surface models of different complexity: API and SURFEX

    USDA-ARS?s Scientific Manuscript database

    Real-time rainfall accumulation estimates at the global scale is useful for many applications. However, the real-time versions of satellite-based rainfall products are known to contain errors relative to real rainfall observed in situ. Recent studies have demonstrated how information about rainfall ...

  15. Lightning NOx Production in CMAQ: Part II - Parameterization Based on Relationship between Observed NLDN Lightning Strikes and Modeled Convective Precipitation Rates

    EPA Science Inventory

    Lightning-produced nitrogen oxides (NOX=NO+NO2) in the middle and upper troposphere play an essential role in the production of ozone (O3) and influence the oxidizing capacity of the troposphere. Despite much effort in both observing and modeling lightning NOX during the past dec...

  16. Lightning NOx Production in CMAQ: Part II - Parameterization Based on Relationship between Observed NLDN Lightning Strikes and Modeled Convective Precipitation Rates

    EPA Science Inventory

    Lightning-produced nitrogen oxides (NOX=NO+NO2) in the middle and upper troposphere play an essential role in the production of ozone (O3) and influence the oxidizing capacity of the troposphere. Despite much effort in both observing and modeling lightning NOX during the past dec...

  17. Impacts of extreme precipitation and seasonal changes in precipitation on plants

    NASA Astrophysics Data System (ADS)

    Zeppel, M. J. B.; Wilks, J. V.; Lewis, J. D.

    2014-06-01

    The global hydrological cycle is predicted to become more intense in future climates, with both larger precipitation events and longer times between events in some regions. Redistribution of precipitation may occur both within and across seasons, and the resulting wide fluctuations in soil water content (SWC) may dramatically affect plants. Though these responses remain poorly understood, recent research in this emerging field suggests the effects of redistributed precipitation may differ from predictions based on previous drought studies. We review available studies on both extreme precipitation (redistribution within seasons) and seasonal changes in precipitation (redistribution across seasons) on grasslands and forests. Extreme precipitation differentially affected above-ground net primary productivity (ANPP), depending on whether extreme precipitation led to increased or decreased SWC, which differed based on the current precipitation and aridity index of the site. Specifically, studies to date reported that extreme precipitation decreased ANPP in mesic sites, but, conversely, increased ANPP in xeric sites, suggesting that plant-available water is a key factor driving responses to extreme precipitation. Similarly, the effects of seasonal changes in precipitation on ANPP, phenology, and leaf and fruit development varied with the effect on SWC. Reductions in spring or summer generally had negative effects on plants, associated with reduced SWC, while subsequent reductions in autumn or winter had little effect on SWC or plants. Similarly, increased summer precipitation had a more dramatic impact on plants than winter increases in precipitation. The patterns of response suggest xeric biomes may respond positively to extreme precipitation, while comparatively mesic biomes may be more likely to be negatively affected. Moreover, seasonal changes in precipitation during warm or dry seasons may have larger effects than changes during cool or wet seasons. Accordingly

  18. Centrifugal precipitation chromatography.

    PubMed

    Ito, Yoichiro; Qi, Lin

    2010-01-15

    Centrifugal precipitation chromatography separates analytes according their solubility in ammonium sulfate (AS) solution and other precipitants. The separation column is made from a pair of long spiral channels partitioned with a semipermeable membrane. In a typical separation, concentrated ammonium sulfate is eluted through one channel while water is eluted through the other channel in the opposite direction. This countercurrent process forms an exponential AS concentration gradient through the water channel. Consequently, protein samples injected into the water channel is subjected to a steadily increasing AS concentration and at the critical AS concentration they are precipitated and deposited in the channel bed by the centrifugal force. Then the chromatographic separation is started by gradually reducing the AS concentration in the AS channel which lowers the AS gradient concentration in the water channel. This results in dissolution of deposited proteins which are again precipitated at an advanced critical point as they move through the channel. Consequently, proteins repeat precipitation and dissolution through a long channel and finally eluted out from the column in the order of their solubility in the AS solution. The present method has been successfully applied to a number of analytes including human serum proteins, recombinant ketosteroid isomerase, carotenoid cleavage enzymes, plasmid DNA, polysaccharide, polymerized pigments, PEG-protein conjugates, etc. The method is capable to single out the target species of proteins by affinity ligand or immunoaffinity separation.

  19. as the Strengthening Precipitates

    NASA Astrophysics Data System (ADS)

    Lu, Qi; Xu, Wei; van der Zwaag, Sybrand

    2014-12-01

    Generally, Laves phase and M23C6 are regarded as undesirable phases in creep-resistant steels due to their very high-coarsening rates and the resulting depletion of beneficial alloying elements from the matrix. In this study, a computational alloy design approach is presented to develop martensitic steels strengthened by Laves phase and/or M23C6, for which the coarsening rates are tailored such that they are at least one order of magnitude lower than those in existing alloys. Their volume fractions are optimized by tuning the chemical composition in parallel. The composition domain covering 10 alloying elements at realistic levels is searched by a genetic algorithm to explore the full potential of simultaneous maximization of the volume fraction and minimization of the precipitates coarsening rate. The calculations show that Co and W can drastically reduce the coarsening rate of Laves and M23C6 and yield high-volume fractions of precipitates. Mo on the other hand was shown to have a minimal effect on coarsening. The strengthening effects of Laves phase and M23C6 in the newly designed alloys are compared to existing counterparts, showing substantially higher precipitation-strengthening contributions especially after a long service time. New alloys were designed in which both Laves phase and M23C6 precipitates act as strengthening precipitates. Successfully combining MX and M23C6 was found to be impossible.

  20. Using GRACE to constrain precipitation amount over cold mountainous basins

    NASA Astrophysics Data System (ADS)

    Behrangi, Ali; Gardner, Alex S.; Reager, John T.; Fisher, Joshua B.

    2017-01-01

    Despite the importance for hydrology and climate-change studies, current quantitative knowledge on the amount and distribution of precipitation in mountainous and high-elevation regions is limited due to instrumental and retrieval shortcomings. Here by focusing on two large endorheic basins in High Mountain Asia, we show that satellite gravimetry (Gravity Recovery and Climate Experiment (GRACE)) can be used to provide an independent estimate of monthly accumulated precipitation using mass balance equation. Results showed that the GRACE-based precipitation estimate has the highest agreement with most of the commonly used precipitation products in summer, but it deviates from them in cold months, when the other products are expected to have larger errors. It was found that most of the products capture about or less than 50% of the total precipitation estimated using GRACE in winter. Overall, Global Precipitation Climatology Project (GPCP) showed better agreement with GRACE estimate than other products. Yet on average GRACE showed 30% more annual precipitation than GPCP in the study basins. In basins of appropriate size with an absence of dense ground measurements, as is a typical case in cold mountainous regions, we find GRACE can be a viable alternative to constrain monthly and seasonal precipitation estimates from other remotely sensed precipitation products that show large bias.

  1. Uncertainty Estimation of Global Precipitation Measurement through Objective Validation Strategy

    NASA Astrophysics Data System (ADS)

    KIM, H.; Utsumi, N.; Seto, S.; Oki, T.

    2014-12-01

    Since Tropical Rainfall Measuring Mission (TRMM) has been launched in 1997 as the first satellite mission dedicated to measuring precipitation, the spatiotemporal gaps of precipitation observation have been filled significantly. On February 27th, 2014, Dual-frequency Precipitation Radar (DPR) satellite has been launched as a core observatory of Global Precipitation Measurement (GPM), an international multi-satellite mission aiming to provide the global three hourly map of rainfall and snowfall. In addition to Ku-band, Ka-band radar is newly equipped, and their combination is expected to introduce higher precision than the precipitation measurement of TRMM/PR. In this study, the GPM level-2 orbit products are evaluated comparing to various precipitation observations which include TRMM/PR, in-situ data, and ground radar. In the preliminary validation over intercross orbits of DPR and TRMM, Ku-band measurements in both satellites shows very close spatial pattern and intensity, and the DPR is capable to capture broader range of precipitation intensity than of the TRMM. Furthermore, we suggest a validation strategy based on 'objective classification' of background atmospheric mechanisms. The Japanese 55-year Reanalysis (JRA-55) and auxiliary datasets (e.g., tropical cyclone best track) is used to objectively determine the types of precipitation. Uncertainty of abovementioned precipitation products is quantified as their relative differences and characterized for different precipitation mechanism. Also, it is discussed how the uncertainty affects the synthesis of TRMM and GPM for a long-term satellite precipitation observation records which is internally consistent.

  2. FORMATION OF URANIUM PRECIPITATES

    DOEpatents

    Googin, J.M. Jr.

    1959-03-17

    A method is described for precipitation of uranium peroxide from uranium- containing solutions so as to obtain larger aggregates which facilitates washings decantations filtrations centrifugations and the like. The desired larger aggregate form is obtained by maintaining the pH of the solution in the approximate range of 1 to 3 and the temperature at about 25 deg C or below while carrytng out the precipitation. Then prior to removal of the precipitate a surface active sulfonated bicarboxyacids such as di-octyl sodium sulfo-succinates is incorporated in an anount of the order of 0.01 to 0.05 percent by weights and the slurry is allowed to ripen for about one-half hour at a temperatare below 10 deg C.

  3. URANIUM PRECIPITATION PROCESS

    DOEpatents

    Thunaes, A.; Brown, E.A.; Smith, H.W.; Simard, R.

    1957-12-01

    A method for the recovery of uranium from sulfuric acid solutions is described. In the present process, sulfuric acid is added to the uranium bearing solution to bring the pH to between 1 and 1.8, preferably to about 1.4, and aluminum metal is then used as a reducing agent to convert hexavalent uranium to the tetravalent state. As the reaction proceeds, the pH rises amd a selective precipitation of uranium occurs resulting in a high grade precipitate. This process is an improvement over the process using metallic iron, in that metallic aluminum reacts less readily than metallic iron with sulfuric acid, thus avoiding consumption of the reducing agent and a raising of the pH without accomplishing the desired reduction of the hexavalent uranium in the solution. Another disadvantage to the use of iron is that positive ferric ions will precipitate with negative phosphate and arsenate ions at the pH range employed.

  4. Simultaneous chemical oxygen demand removal, methane production and heavy metal precipitation in the biological treatment of landfill leachate using acid mine drainage as sulfate resource.

    PubMed

    Li, Yu-Long; Wang, Jin; Yue, Zheng-Bo; Tao, Wei; Yang, Hai-Bin; Zhou, Yue-Fei; Chen, Tian-Hu

    2017-03-06

    Biological treatment played an important role in the treatment of landfill leachate. In the current study, acid mine drainage (AMD) was used as a source of sulfate to strengthen the anaerobic treatment of landfill leachate. Effects of chemical oxygen demand (COD) and SO4(2-) mass concentration ratio on the decomposition of organic matter, methane production and sulfate reduction were investigated and the microbial community was analyzed using the high throughout methods. Results showed that high removal efficiency of COD, methane production and heavy metal removal was achieved when the initial COD/SO4(2-) ratio (based on mass) was set at 3.0. The relative abundance of anaerobic hydrogen-producing bacteria (Candidatus Cloacamonas) in the experimental group with the addition of AMD was significantly increased compared to the control. Abundance of hydrogenotrophic methanogens of Methanosarcina and Methanomassiliicoccus was increased. Results confirmed that AMD could be used as sulfate resource to strengthen the biological treatment of landfill leachate.

  5. Precipitation-Regulated Feedback

    NASA Astrophysics Data System (ADS)

    Voit, Mark

    2016-07-01

    Star formation in the central galaxies of galaxy clusters appears to be fueled by precipitation of cold clouds out of hot circumgalactic gas via thermal instability. I will present both observational and theoretical support for the precipitation mode in large galaxies and discuss how it can be implemented in cosmological simulations of galaxy evolution. Galaxy cluster cores are unique laboratories for studying the astrophysics of thermal instability and may be teaching us valuable lessons about how feedback works in galaxies spanning the entire mass spectrum.

  6. Satellite precipitation estimation over the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Porcu, F.; Gjoka, U.

    2012-04-01

    Precipitation characteristics over the Tibetan Plateau are very little known, given the scarcity of reliable and widely distributed ground observation, thus the satellite approach is a valuable choice for large scale precipitation analysis and hydrological cycle studies. However,the satellite perspective undergoes various shortcomings at the different wavelengths used in atmospheric remote sensing. In the microwave spectrum often the high soil emissivity masks or hides the atmospheric signal upwelling from light-moderate precipitation layers, while low and relatively thin precipitating clouds are not well detected in the visible-infrared, because of their low contrast with cold and bright (if snow covered) background. In this work an IR-based, statistical rainfall estimation technique is trained and applied over the Tibetan Plateau hydrological basin to retrive precipitation intensity at different spatial and temporal scales. The technique is based on a simple artificial neural network scheme trained with two supervised training sets assembled for monsoon season and for the rest of the year. For the monsoon season (estimated from June to September), the ground radar precipitation data for few case studies are used to build the training set: four days in summer 2009 are considered. For the rest of the year, CloudSat-CPR derived snowfall rate has been used as reference precipitation data, following the Kulie and Bennartz (2009) algorithm. METEOSAT-7 infrared channels radiance (at 6.7 and 11 micometers) and derived local variability features (such as local standard deviation and local average) are used as input and the actual rainrate is obtained as output for each satellite slot, every 30 minutes on the satellite grid. The satellite rainrate maps for three years (2008-2010) are computed and compared with available global precipitation products (such as C-MORPH and TMPA products) and with other techniques applied to the Plateau area: similarities and differences are

  7. Layer Precipitable Water (LPW) Briefing

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  8. Calcium precipitate induced aerobic granulation.

    PubMed

    Wan, Chunli; Lee, Duu-Jong; Yang, Xue; Wang, Yayi; Wang, Xingzu; Liu, Xiang

    2015-01-01

    Aerobic granulation is a novel biotechnology for wastewater treatment. This study refined existing aerobic granulation mechanisms as a sequencing process including formation of calcium precipitate under alkaline pH to form inorganic cores, followed by bacterial attachment and growth on these cores to form the exopolysaccharide matrix. Mature granules comprised an inner core and a matrix layer and a rim layer with enriched microbial strains. The inorganic core was a mix of different crystals of calcium and phosphates. Functional strains including Sphingomonas sp., Paracoccus sp. Sinorhizobium americanum strain and Flavobacterium sp. attached onto the cores. These functional strains promote c-di-GMP production and the expression by Psl and Alg genes for exopolysaccharide production to enhance formation of mature granules.

  9. Total Precipitable Water

    SciTech Connect

    2012-01-01

    The simulation was performed on 64K cores of Intrepid, running at 0.25 simulated-years-per-day and taking 25 million core-hours. This is the first simulation using both the CAM5 physics and the highly scalable spectral element dynamical core. The animation of Total Precipitable Water clearly shows hurricanes developing in the Atlantic and Pacific.

  10. The Global Precipitation Mission

    NASA Technical Reports Server (NTRS)

    Braun, Scott; Kummerow, Christian

    2000-01-01

    The Global Precipitation Mission (GPM), expected to begin around 2006, is a follow-up to the Tropical Rainfall Measuring Mission (TRMM). Unlike TRMM, which primarily samples the tropics, GPM will sample both the tropics and mid-latitudes. The primary, or core, satellite will be a single, enhanced TRMM satellite that can quantify the 3-D spatial distributions of precipitation and its associated latent heat release. The core satellite will be complemented by a constellation of very small and inexpensive drones with passive microwave instruments that will sample the rainfall with sufficient frequency to be not only of climate interest, but also have local, short-term impacts by providing global rainfall coverage at approx. 3 h intervals. The data is expected to have substantial impact upon quantitative precipitation estimation/forecasting and data assimilation into global and mesoscale numerical models. Based upon previous studies of rainfall data assimilation, GPM is expected to lead to significant improvements in forecasts of extratropical and tropical cyclones. For example, GPM rainfall data can provide improved initialization of frontal systems over the Pacific and Atlantic Oceans. The purpose of this talk is to provide information about GPM to the USWRP (U.S. Weather Research Program) community and to discuss impacts on quantitative precipitation estimation/forecasting and data assimilation.

  11. Global precipitation measurement (GPM)

    NASA Astrophysics Data System (ADS)

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

    2001-12-01

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

  12. The Global Precipitation Mission

    NASA Technical Reports Server (NTRS)

    Braun, Scott; Kummerow, Christian

    2000-01-01

    The Global Precipitation Mission (GPM), expected to begin around 2006, is a follow-up to the Tropical Rainfall Measuring Mission (TRMM). Unlike TRMM, which primarily samples the tropics, GPM will sample both the tropics and mid-latitudes. The primary, or core, satellite will be a single, enhanced TRMM satellite that can quantify the 3-D spatial distributions of precipitation and its associated latent heat release. The core satellite will be complemented by a constellation of very small and inexpensive drones with passive microwave instruments that will sample the rainfall with sufficient frequency to be not only of climate interest, but also have local, short-term impacts by providing global rainfall coverage at approx. 3 h intervals. The data is expected to have substantial impact upon quantitative precipitation estimation/forecasting and data assimilation into global and mesoscale numerical models. Based upon previous studies of rainfall data assimilation, GPM is expected to lead to significant improvements in forecasts of extratropical and tropical cyclones. For example, GPM rainfall data can provide improved initialization of frontal systems over the Pacific and Atlantic Oceans. The purpose of this talk is to provide information about GPM to the USWRP (U.S. Weather Research Program) community and to discuss impacts on quantitative precipitation estimation/forecasting and data assimilation.

  13. Precipitation from Space: Advancing Earth System Science

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

    Of the three primary sources of spatially contiguous precipitation observations (surface networks, ground-based radar, and satellite-based radar/radiometers), only the last is a viable source over ocean and much of the Earth's land. As recently as 15 years ago, users needing quantitative detail of precipitation on anything under a monthly time scale relied upon products derived from geostationary satellite thermal infrared (IR) indices. The Special Sensor Microwave Imager (SSMI) passive microwave (PMW) imagers originated in 1987 and continue today with the SSMI sounder (SSMIS) sensor. The fortunate longevity of the joint National Aeronautics and Space Administration (NASA) and Japan Aerospace Exploration Agency (JAXA) Tropical Rainfall Measuring Mission (TRMM) is providing the environmental science community a nearly unbroken data record (as of April 2012, over 14 years) of tropical and sub-tropical precipitation processes. TRMM was originally conceived in the mid-1980s as a climate mission with relatively modest goals, including monthly averaged precipitation. TRMM data were quickly exploited for model data assimilation and, beginning in 1999 with the availability of near real time data, for tropical cyclone warnings. To overcome the intermittently spaced revisit from these and other low Earth-orbiting satellites, many methods to merge PMW-based precipitation data and geostationary satellite observations have been developed, such as the TRMM Multisatellite Precipitation Product and the Climate Prediction Center (CPC) morphing method (CMORPH. The purpose of this article is not to provide a survey or assessment of these and other satellite-based precipitation datasets, which are well summarized in several recent articles. Rather, the intent is to demonstrate how the availability and continuity of satellite-based precipitation data records is transforming the ways that scientific and societal issues related to precipitation are addressed, in ways that would not be

  14. The TRMM Multi-satellite Precipitation Analysis (TMPA): Quasi-Global Precipitation Estimates at Fine Scales

    NASA Technical Reports Server (NTRS)

    Huffman, George J.; Adler, Robert F.; Bolvin, David T.; Gu, Guojun; Nelkin, Eric J.; Bowman, Kenneth P.; Stocker, Erich; Wolff, David B.

    2006-01-01

    The TRMM Multi-satellite Precipitation Analysis (TMPA) provides a calibration-based sequential scheme for combining multiple precipitation estimates from satellites, as well as gauge analyses where feasible, at fine scales (0.25 degrees x 0.25 degrees and 3-hourly). It is available both after and in real time, based on calibration by the TRMM Combined Instrument and TRMM Microwave Imager precipitation products, respectively. Only the after-real-time product incorporates gauge data at the present. The data set covers the latitude band 50 degrees N-S for the period 1998 to the delayed present. Early validation results are as follows: The TMPA provides reasonable performance at monthly scales, although it is shown to have precipitation rate dependent low bias due to lack of sensitivity to low precipitation rates in one of the input products (based on AMSU-B). At finer scales the TMPA is successful at approximately reproducing the surface-observation-based histogram of precipitation, as well as reasonably detecting large daily events. The TMPA, however, has lower skill in correctly specifying moderate and light event amounts on short time intervals, in common with other fine-scale estimators. Examples are provided of a flood event and diurnal cycle determination.

  15. Illinois Precipitation Research: A Focus on Cloud and Precipitation Modification.

    NASA Astrophysics Data System (ADS)

    Changnon, Stanley A.; Czys, Robert R.; Scott, Robert W.; Westcott, Nancy E.

    1991-05-01

    At the heart of the 40-year atmospheric research endeavors of the Illinois State Water Survey have been studies to understand precipitation processes in order to learn how precipitation is modified purposefully and accidentally, and to measure the physical and socio-economic consequences of cloud and precipitation modification. Major field and laboratory activities of past years or briefly treated as a basis for describing the key findings of the past ten years. Recent studies of inadvertent and purposeful cloud and rain modification and their effects are emphasized, including a 1989 field project conducted in Illinois and key findings from an on-going exploratory experiment addressing cloud and rain modification. Results are encouraging for the use of dynamic seeding on summer cumuliform clouds of the Midwest.Typical in-cloud results at 10°C reveal multiple updrafts that tend to be filled with large amounts of supercooled drizzle and raindrops. Natural ice production is vigorous, and initial concentrations are larger than expected from ice nuclei. However, natural ice production is not so vigorous as to preclude opportunities for seeding. Radar-based studies of such clouds reveal that their echo cores usually can be identified prior to desired seeding times, which is significant for the evaluation of their behavior. Cell characteristics show considerable variance under different types of meteorological conditions. Analysis of cell mergers reveals that under conditions of weak vertical shear, mid-level intercell flow at 4 km occurs as the reflectivity bridge between cells rapidly intensifies. The degree of intensification of single-echo cores after they merge is strongly related to the age and vigor of the cores before they join. Hence, cloud growth may be enhanced if seeding can encourage echo cores to merge at critical times. Forecasting research has developed a technique for objectively distinguishing between operational seeding and nonoperational days and for

  16. Nordic Seas Precipitation Ground Validation Project

    NASA Astrophysics Data System (ADS)

    Klepp, Christian; Bumke, Karl; Bakan, Stephan; Andersson, Axel

    2010-05-01

    A thorough knowledge of global ocean precipitation is an indispensable prerequisite for the understanding of the water cycle in the global climate system. However, reliable detection of precipitation over the global oceans, especially of solid precipitation, remains a challenging task. This is true for both, passive microwave remote sensing and reanalysis based model estimates. The satellite based HOAPS (Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data) climatology contains fields of precipitation, evaporation and the resulting freshwater flux along with 12 additional atmospheric parameters over the global ice-free ocean between 1987 and 2005. Except for the NOAA Pathfinder SST, all basic state variables are calculated from SSM/I passive microwave radiometer measurements. HOAPS contains three main data subsets that originate from one common pixel-level data source. Gridded 0.5 degree monthly, pentad and twice daily data products are freely available from www.hoaps.org. The optical disdrometer ODM 470 is a ground validation instrument capable of measuring rain and snowfall on ships even under high wind speeds. It was used for the first time over the Nordic Seas during the LOFZY 2005 campaign. A dichotomous verification for these snowfall events resulted in a perfect score between the disdrometer, a precipitation detector and a shipboard observer's log. The disdrometer data is further point-to-area collocated against precipitation from three satellite derived climatologies, HOAPS-3, the Global Precipitation Climatology Project (GPCP) one degree daily (1DD) data set, and the Goddard Profiling algorithm, version 2004 (GPROF 2004). Only the HOAPS precipitation turns out to be overall consistent with the disdrometer data resulting in an accuracy of 0.96. The collocated data comprises light precipitation events below 1 mm/h. Therefore two LOFZY case studies with high precipitation rates are presented that still indicate plausible results. Overall, this

  17. Homogeneous Precipitation of Nickel Hydroxide Powders

    SciTech Connect

    Mavis, Bora

    2003-01-01

    Precipitation and characterization of nickel hydroxide powders were investigated. A comprehensive precipitation model incorporating the metal ion hydrolysis, complexation and precipitation reactions was developed for the production of the powders with urea precipitation method. Model predictions on Ni2+ precipitation rate were confirmed with precipitation experiments carried out at 90 C. Experimental data and model predictions were in remarkable agreement. Uncertainty in the solubility product data of nickel hydroxides was found to be the large contributor to the error. There were demonstrable compositional variations across the particle cross-sections and the growth mechanism was determined to be the aggregation of primary crystallites. This implied that there is a change in the intercalate chemistry of the primary crystallites with digestion time. Predicted changes in the concentrations of simple and complex ions in the solution support the proposed mechanism. The comprehensive set of hydrolysis reactions used in the model described above allows the investigation of other systems provided that accurate reaction constants are available. the fact that transition metal ions like Ni2+ form strong complexes with ammonia presents a challenge in the full recovery of the Ni2+. On the other hand, presence of Al3+ facilitates the complete precipitation of Ni2+ in about 3 hours of digestion. A challenge in their predictive modeling studies had been the fact that simultaneous incorporation of more than one metal ion necessitates a different approach than just using the equilibrium constants of hydrolysis, complexation and precipitation reactions. Another limitation of using equilibrium constants is that the nucleation stage of digestion, which is controlled mainly by kinetics, is not fully justified. A new program released by IBM Almaden Research Center (Chemical Kinetics Simulator™, Version 1.01) lets the user change

  18. Assimilating the Global Precipitation Measurement (GPM) Estimates in the Canadian Precipitation Analysis (CaPA) Over North America.

    NASA Astrophysics Data System (ADS)

    Boluwade, A.; Rasmussen, P. F.; Stadnyk, T. A.; Fortin, V.; Guy, R.

    2015-12-01

    The importance of precipitation measurement using estimates from satellite products cannot be over emphasized. Observations from space using sensors mounted on satellites cover wider areas and provide high spatial and temporal resolution. The estimates derived from this process are very useful in integrated hydrologic modeling, weather forecasting and monitoring landslides, droughts and floods, etc. Example of a satellite precipitation product is the Tropical Rainfall Measurement Mission (TRMM) and Global Precipitation Mission (GPM). TRMM was primarily designed to measure heavy-to-moderate rainfall over tropical and subtropical regions. GPM was designed to extend, enhance, and improve TRMM precipitation data. The primary objective of this study is the assimilation GPM satellite based precipitation estimates into the Canadian Precipitation Analysis (CaPA). CaPA combines the Global Environmental Multi-Scale model (GEM) dataset and observed precipitation from monitoring stations to provide precipitation estimates at 6hr and 24hr time steps and spatial resolution of 10km covering North America. In the result, we used the Equitable Threat Score (ETS) as performance evaluation. GPM assimilation provides higher skill (ETS) at precipitation values below 3mm while being used as additional data source. GPM has better skill as background field at precipitation value above 3mm.

  19. Precipitation hardening austenitic superalloys

    DOEpatents

    Korenko, Michael K.

    1985-01-01

    Precipitation hardening, austenitic type superalloys are described. These alloys contain 0.5 to 1.5 weight percent silicon in combination with about 0.05 to 0.5 weight percent of a post irradiation ductility enhancing agent selected from the group of hafnium, yttrium, lanthanum and scandium, alone or in combination with each other. In addition, when hafnium or yttrium are selected, reductions in irradiation induced swelling have been noted.

  20. A test for Improvement of high resolution Quantitative Precipitation Estimation for localized heavy precipitation events

    NASA Astrophysics Data System (ADS)

    Lee, Jung-Hoon; Roh, Joon-Woo; Park, Jeong-Gyun

    2017-04-01

    Accurate estimation of precipitation is one of the most difficult and significant tasks in the area of weather diagnostic and forecasting. In the Korean Peninsula, heavy precipitations are caused by various physical mechanisms, which are affected by shortwave trough, quasi-stationary moisture convergence zone among varying air masses, and a direct/indirect effect of tropical cyclone. In addition to, various geographical and topographical elements make production of temporal and spatial distribution of precipitation is very complicated. Especially, localized heavy rainfall events in South Korea generally arise from mesoscale convective systems embedded in these synoptic scale disturbances. In weather radar data with high temporal and spatial resolution, accurate estimation of rain rate from radar reflectivity data is too difficult. Z-R relationship (Marshal and Palmer 1948) have adapted representatively. In addition to, several methods such as support vector machine (SVM), neural network, Fuzzy logic, Kriging were utilized in order to improve the accuracy of rain rate. These methods show the different quantitative precipitation estimation (QPE) and the performances of accuracy are different for heavy precipitation cases. In this study, in order to improve the accuracy of QPE for localized heavy precipitation, ensemble method for Z-R relationship and various techniques was tested. This QPE ensemble method was developed by a concept based on utilizing each advantage of precipitation calibration methods. The ensemble members were produced for a combination of different Z-R coefficient and calibration method.

  1. Precipitation Storage Efficiency During Fallow in Wheat-Fallow Systems

    USDA-ARS?s Scientific Manuscript database

    Wheat-fallow production systems arose in order to stabilize widely ranging wheat yields that resulted from highly variable precipitation in the Great Plains. Historically, precipitation storage efficiency (PSE) over the fallow period increased over time as inversion tillage systems used for weed con...

  2. A multi-source precipitation approach to fill gaps over a radar precipitation field

    NASA Astrophysics Data System (ADS)

    Tesfagiorgis, K. B.; Mahani, S. E.; Khanbilvardi, R.

    2012-12-01

    Satellite Precipitation Estimates (SPEs) may be the only available source of information for operational hydrologic and flash flood prediction due to spatial limitations of radar and gauge products. The present work develops an approach to seamlessly blend satellite, radar, climatological and gauge precipitation products to fill gaps over ground-based radar precipitation fields. To mix different precipitation products, the bias of any of the products relative to each other should be removed. For bias correction, the study used an ensemble-based method which aims to estimate spatially varying multiplicative biases in SPEs using a radar rainfall product. Bias factors were calculated for a randomly selected sample of rainy pixels in the study area. Spatial fields of estimated bias were generated taking into account spatial variation and random errors in the sampled values. A weighted Successive Correction Method (SCM) is proposed to make the merging between error corrected satellite and radar rainfall estimates. In addition to SCM, we use a Bayesian spatial method for merging the gap free radar with rain gauges, climatological rainfall sources and SPEs. We demonstrate the method using SPE Hydro-Estimator (HE), radar- based Stage-II, a climatological product PRISM and rain gauge dataset for several rain events from 2006 to 2008 over three different geographical locations of the United States. Results show that: the SCM method in combination with the Bayesian spatial model produced a precipitation product in good agreement with independent measurements. The study implies that using the available radar pixels surrounding the gap area, rain gauge, PRISM and satellite products, a radar like product is achievable over radar gap areas that benefits the scientific community.

  3. A unified approach to asphaltene precipitation: Laboratory measurement and modeling

    SciTech Connect

    MacMillan, D.J.; Tackett, J.E. Jr.; Jessee, M.A.; Monger-McClure, T.G.

    1995-11-01

    A unified approach to evaluating asphaltene precipitation based on laboratory measurement and modeling is presented. This approach used an organic deposition cell for measuring asphaltene drop out onset conditions. Asphaltene precipitation was detected by changes in optical fluorescence, electrical conductance, and visual observation. A series of experiments measured the effects of changing pressure, temperature and composition on asphaltene precipitation. A fully-compositional V-L-S mathematical model completed the analysis by matching the experimental results. The model was then used to forecast asphaltene precipitation under a variety of production scenarios including response to gas-lift operations, and to evaluate the possible location of a tar-mat.

  4. Precipitation Indices Low Countries

    NASA Astrophysics Data System (ADS)

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

    2009-09-01

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

  5. CALCULATION: PRECIPITATION CHARACTERISITICS FOR STORM WATER MANAGEMENT

    SciTech Connect

    D. Ambos

    2000-08-14

    This Calculation is intended to satisfy engineering requirements for maximum 60-minute precipitation amounts for 50 and 100-year return periods at and near Yucca Mountain. This data requirement is documented in the ''Interface Control Document for Support Operations to Surface Facilities Operations Functional and Organizational Interfaces'' (CRWMS M&O 1998a). These developed data will supplement the information on 0.1 hour to 6-hour (in 0.1-hour increments) probable maximum precipitation (PMP) presented in the report, ''Precipitation Design Criteria for Storm Water Management'' (CRWMS M&O 1998b). The Reference Information Base (RIB) item, Precipitation ''Characteristics for Storm Water Management'' (M09902RIB00045 .OOO), was developed based on CRWMS M&O (1998b) and will be supplemented (via revision) with the information developed in this Calculation. The ''Development Plan for the Calculation: Precipitation Characteristics for Storm Water Management'' (CRWMS M&O 2000) was prepared in accordance with AP-2.l3Q, ''Technical Product Development Planning''. This calculation was developed in accordance with AP-3.12Q, Rev. O/ICN 2.

  6. Magnetite seeded precipitation of phosphate.

    PubMed

    Karapinar, Nuray; Hoffmann, Erhard; Hahn, Hermann H

    2004-07-01

    Seeded precipitation of Ca phosphate on magnetite mineral (Fe3O4) surfaces was investigated using a Jar Test system in supersaturated solutions at 20 degrees C and ionic strength 0.01 mol l(-1) with relative super saturation, 12.0-20.0 for HAP. pH of the solution, initial phosphorus concentration and molar Ca/P ratio were investigated as the main parameters, which effect the seeded precipitation of Ca phosphate. Results showed that there is no pronounced effect of magnetite seed, neither positive nor negative on the amount of calcium phosphate precipitation. pH was found to be the main parameter that determines the phosphate precipitated onto the seed surface. Increasing of the pH of precipitation reaction was resulted in the decrease in percentage amount of phosphate precipitated onto seed surfaces to total precipitation (magnetite seeded precipitation efficiency). It was concluded that the pH dependence of magnetite-seeded precipitation should be considered in the light of its effect on the supersaturated conditions of solution. Saturation index (SI) of solution with respect to the precipitate phase was considered the driving force for the precipitation. A simulation programme PHREEQC (Version 2) was employed to calculate the Saturation-index with respect to hydroxyapatite (HAP) of the chemically defined precipitation system. It was found a good relationship between SI of solution with respect to HAP and the magnetite seeded precipitation efficiency, a second order polynomial function. Results showed that more favorable solution conditions for precipitation (higher SI values of solution) causes homogenous nucleation whereas heterogeneous nucleation led to a higher magnetite seeded precipitation efficiency.

  7. Measurement of Global Precipitation

    NASA Technical Reports Server (NTRS)

    Flaming, Gilbert Mark

    2004-01-01

    The Global Precipitation Measurement (GPM) Program is an international cooperative effort whose objectives are to (a) obtain increased understanding of rainfall processes, and (b) make frequent rainfall measurements on a global basis. The National Aeronautics and Space Administration (NASA) of the United States and the Japanese Aviation and Exploration Agency (JAXA) have entered into a cooperative agreement for the formulation and development of GPM. This agreement is a continuation of the partnership that developed the highly successful Tropical Rainfall Measuring Mission (TRMM) that was launched in November 1997; this mission continues to provide valuable scientific and meteorological information on rainfall and the associated processes. International collaboration on GPM from other space agencies has been solicited, and discussions regarding their participation are currently in progress. NASA has taken lead responsibility for the planning and formulation of GPM, Key elements of the Program to be provided by NASA include a Core satellite bus instrumented with a multi-channel microwave radiometer, a Ground Validation System and a ground-based Precipitation Processing System (PPS). JAXA will provide a Dual-frequency Precipitation Radar for installation on the Core satellite and launch services. Other United States agencies and international partners may participate in a number of ways, such as providing rainfall measurements obtained from their own national space-borne platforms, providing local rainfall measurements to support the ground validation activities, or providing hardware or launch services for GPM constellation spacecraft. This paper will present an overview of the current planning for the GPM Program, and discuss in more detail the status of the lead author's primary responsibility, development and acquisition of the GPM Microwave Imager.

  8. Bias Adjustment of high spatial/temporal resolution Satellite Precipitation Estimation relying on Gauge-Based precipitation over China

    NASA Astrophysics Data System (ADS)

    Yu, J.; Pan, Y.; Shen, Y.

    2010-12-01

    Satellite precipitation data has been widely used in the forecasting and research of weather and climate because of its high spatial/temporal resolution, especially in the area of limited access to ground-based measurements. The distribution of gauge stations in China is very uniform with most gauge stations located in Eastern China and few gauge stations located in Western China. So the using of satellite precipitation data in China is very important. Although the satellite precipitation data has a good spatial construction, its estimation value is less accurate and has distinct systematic bias comparing to gauge-based one. The bias of satellite precipitation data should be adjusted before using it. In this paper, the CMORPH (Climate Prediction Center Morphing Technique) 30-min precipitation products is chosen to represent the large-scale precipitation of China and be adjusted based on hourly rain gauge analysis over China by interpolating from more than 10000 stations collected and quality controlled by the National Meteorological Information Center of the China Meteorological by using a probability density function (PDF) matching method (Wang and Xie, 2005). After bias-adjustment by PDF matching, we get a less systematic bias and high-resolution satellite precipitation product, which is hourly precipitation on a 0.1°latitude/longitude grid over China. Adjusted values are more close to the gauge observations, and the probability density function of corrected precipitation products is the same as that of the gauge-based precipitation. In Western China, the quantity value of corrected precipitation estimates is obviously increased comparing to the original estimate value. On the other hand, the spatial construction is still maintenance of satellite products.

  9. Precipitation alters interactions in a grassland ecological community.

    PubMed

    Deguines, Nicolas; Brashares, Justin S; Prugh, Laura R

    2017-03-01

    Climate change is transforming precipitation regimes world-wide. Changes in precipitation regimes are known to have powerful effects on plant productivity, but the consequences of these shifts for the dynamics of ecological communities are poorly understood. This knowledge gap hinders our ability to anticipate and mitigate the impacts of climate change on biodiversity. Precipitation may affect fauna through direct effects on physiology, behaviour or demography, through plant-mediated indirect effects, or by modifying interactions among species. In this paper, we examined the response of a semi-arid ecological community to a fivefold change in precipitation over 7 years. We examined the effects of precipitation on the dynamics of a grassland ecosystem in central California from 2007 to 2013. We conducted vegetation surveys, pitfall trapping of invertebrates, visual surveys of lizards and capture-mark-recapture surveys of rodents on 30 plots each year. We used structural equation modelling to evaluate the direct, indirect and modifying effects of precipitation on plants, ants, beetles, orthopterans, kangaroo rats, ground squirrels and lizards. We found pervasive effects of precipitation on the ecological community. Although precipitation increased plant biomass, direct effects on fauna were often stronger than plant-mediated effects. In addition, precipitation altered the sign or strength of consumer-resource and facilitative interactions among the faunal community such that negative or neutral interactions became positive or vice versa with increasing precipitation. These findings indicate that precipitation influences ecological communities in multiple ways beyond its recognized effects on primary productivity. Stochastic variation in precipitation may weaken the average strength of biotic interactions over time, thereby increasing ecosystem stability and resilience to climate change.

  10. DISSOLUTION OF LANTHANUM FLUORIDE PRECIPITATES

    DOEpatents

    Fries, B.A.

    1959-11-10

    A plutonium separatory ore concentration procedure involving the use of a fluoride type of carrier is presented. An improvement is given in the derivation step in the process for plutonium recovery by carrier precipitation of plutonium values from solution with a lanthanum fluoride carrier precipitate and subsequent derivation from the resulting plutonium bearing carrier precipitate of an aqueous acidic plutonium-containing solution. The carrier precipitate is contacted with a concentrated aqueous solution of potassium carbonate to effect dissolution therein of at least a part of the precipitate, including the plutonium values. Any remaining precipitate is separated from the resulting solution and dissolves in an aqueous solution containing at least 20% by weight of potassium carbonate. The reacting solutions are combined, and an alkali metal hydroxide added to a concentration of at least 2N to precipitate lanthanum hydroxide concomitantly carrying plutonium values.

  11. Precipitation Extremes Under Climate Change.

    PubMed

    O'Gorman, Paul A

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

  12. Application of Gis Technology for the Precipitation Mapping

    NASA Astrophysics Data System (ADS)

    Dyras, I.; Serafin-Rek, D.

    2003-04-01

    Precipitation is one of the most variable meteorological parameters in time and space. The standard surface measurement network provides a very localised information about the precipitation. The satellite, radar observations and Numerical Weather Prediction (NWP) models provide the continuous information on the state of the atmosphere, however, with the much lower resolution. Combining these data into one system allows analysing the data from different sources in order to estimate the precipitation intensity and range. The paper presents the works undertaken for the Central Europe region for the stratiform and convective precipitation. The analysis results are prepared in the form of maps of precipitation intensity and range. The satellite data available from an Advanced Microwave Sounding Unit (AMSU) on board of NOAA-15, 16 and 17 satellites enhanced the possibilities of the new meteorological precipitation related products derivation. The products such as Rain Rate (RR), Scattering Index (SI), Total Precipitation Water (TPW), Precipitation Probability (PP) and Liquid Water Path (LWP) were prepared basing on the regression algorithms. The data from spring and summer seasons in 2001 and 2002 were used. The temperature and precipitation thematic layers are created from the NWP model grid data. Also SYNOP and TEMP data are converted into thematic coverages. The progress in GIS technology application for NOAA/AMSU microwave derived products preparation and visualization in the Satellite Research Department in Poland was accomplished. The developed system allows displaying the rain field forecasted by the NWP model Aladin and the precipitation observed with the satellite data and other ancillary information. The maps of precipitation with additional geographical data and administrative boundaries are available for the weather forecasting units via Intranet. It is planned to make images available on the web for external customers. Radar and lightning data as well as

  13. Successes with the Global Precipitation Measurement (GPM) Mission

    NASA Technical Reports Server (NTRS)

    Skofronick-Jackson, Gail; Huffman, George; Stocker, Erich; Petersen, Walter

    2016-01-01

    Water is essential to our planet Earth. Knowing when, where and how precipitation falls is crucial for understanding the linkages between the Earth's water and energy cycles and is extraordinarily important for sustaining life on our planet during climate change. The Global Precipitation Measurement (GPM) Core Observatory spacecraft launched February 27, 2014, is the anchor to the GPM international satellite mission to unify and advance precipitation measurements from a constellation of research and operational sensors to provide "next-generation" precipitation products. GPM is currently a partnership between NASA and the Japan Aerospace Exploration Agency (JAXA). Status and successes in terms of spacecraft, instruments, retrieval products, validation, and impacts for science and society will be presented. Precipitation, microwave, satellite

  14. Impacts of Light Precipitation Detection with Dual Frequency Radar on Global Precipitation Measurement Core Observatory (GPM/DPR)

    NASA Astrophysics Data System (ADS)

    Takayabu, Y. N.; Hamada, A.; Oki, R.; Kachi, M.; Kubota, T.; Iguchi, T.; Shige, S.; Nakamura, K.

    2014-12-01

    The Dual-frequency Precipitation Radar (DPR) on board the GPM Core Observatory consists of Ku-band (13.6 GHz) and Ka-band (35.5 GHz) radars, with an improved minimum detection sensitivity of precipitation compared to the Tropical Rainfall Measuring Mission Precipitation Radar (TRMM PR). We have studied impacts of improved detection sensitivity with the GPM DPR compared with the TRMM PR. One example of light precipitation is, a scattered rainfall around a trough over the subtropical South Pacific Ocean, which consists of weak but erect precipitation reaching over the melting level of ~2.5 km and trailing precipitation above, which reaches as high as 5km. Another example is a light anvil precipitation spreading from convective cores of a storm in the upper troposphere, overcasting shallow convective precipitation below. The ability of globally detecting such light precipitation will improve our knowledge of precipitation processes. Utilizing an early version of the DPR product, a quick evaluation on statistical impacts of increasing the detection sensitivity from 17dBZ to 12dBZ has been performed. Here, 17dBZ is the value which is mostly accepted as the performed detection sensitivity of the TRMM PR, and 12dBZ is the guaranteed sensitivity for GPM Ka-band radar. For the near surface precipitation, impacts are significant in terms of numbers, but limited to several regions in terms of the rainfall volume. Volume impacts are much larger at the upper troposphere, which is indicated by the detection of the anvil precipitation, for example. The upper level improvements are mostly found where the deep precipitation systems exist. Quantitative discussions utilizing the latest version of the DPR data, which is scheduled to be released to the public in September, will be presented at the session.

  15. Auroral helium precipitation.

    NASA Technical Reports Server (NTRS)

    Axford, W. I.; Chivers, H. J. A.; Eberhardt, P.; Geiss, J.; Buehler, F.

    1972-01-01

    Application of the metal foil sampling technique, which has been used to measure helium, neon, and argon fluxes in the solar wind, to the problem of measuring the fluxes of these gases in the auroral primary radiation. Aluminum and platinum foils have been flown into two bright auroras and have been recovered. The foils have been analyzed for helium and neon isotopes with a mass spectrometer; so far only He4 has been detected. In the first flight the precipitating flux of He4 with particle energies above about 1 keV was approximately 1,000,000 per sq cm per sec, and the backscattered flux was smaller by about a factor of 10. In the second flight the aurora was less bright, and the He4 fluxes were lower by a factor of about 2. A rough analysis suggests that the mean energy of the incident particles was greater than 3 keV.

  16. Auroral helium precipitation.

    NASA Technical Reports Server (NTRS)

    Axford, W. I.; Chivers, H. J. A.; Eberhardt, P.; Geiss, J.; Buehler, F.

    1972-01-01

    Application of the metal foil sampling technique, which has been used to measure helium, neon, and argon fluxes in the solar wind, to the problem of measuring the fluxes of these gases in the auroral primary radiation. Aluminum and platinum foils have been flown into two bright auroras and have been recovered. The foils have been analyzed for helium and neon isotopes with a mass spectrometer; so far only He4 has been detected. In the first flight the precipitating flux of He4 with particle energies above about 1 keV was approximately 1,000,000 per sq cm per sec, and the backscattered flux was smaller by about a factor of 10. In the second flight the aurora was less bright, and the He4 fluxes were lower by a factor of about 2. A rough analysis suggests that the mean energy of the incident particles was greater than 3 keV.

  17. PROCESS OF TREATING OR FORMING AN INSOLUBLE PLUTONIUM PRECIPITATE IN THE PRESENCE OF AN ORGANIC ACTIVE AGENT

    DOEpatents

    Balthis, J.H.

    1961-07-18

    Carrier precipitation processes for the separation of plutonium from fission products are described. In a process in which an insoluble precipitate is formed in a solution containing plutonium and fission products under conditions whereby plutonium is carried by the precipitate, and the precipitate is then separated from the remaining solution, an organic surface active agent is added to the mixture of precipitate and solution prior to separation of the precipitate from the supernatant solution, thereby improving the degree of separation of the precipitate from the solution.

  18. Immunoaffinity centrifugal precipitation chromatography.

    PubMed

    Qi, Lin; Ito, Yoichiro

    2007-06-01

    Purification of proteins based on immunoaffinity has been performed using a solid support coated with antibody against the target proteins. The method requires immobilizing the antibody onto the solid support using protein A or G, and has a risk of adsorptive loss of target proteins onto the solid support. Centrifugal precipitation chromatography has been successfully used to purify enzymes, such as ketosteroid isomerase and hyaluronidase without the use of solid support. The purpose of this study is to demonstrate that immunoaffinity centrifugal precipitation chromatography is capable of isolating an antigen by exploiting antigen-antibody binding. The separation was initiated by filling both channels with 40% saturated ammonium sulfate (AS) of pH 4-4.5 followed by loading 20 microl of human plasma (National Institutes of Health blood bank) mixed with 2 mg of rabbit anti-HSA (human serum protein) antibody (Sigma). Then, the sample channel was eluted with water at 0.03 ml/min and AS channel with 40% AS solution of pH 4-4.5 at 1 ml/min until all non-binding components were eluted. Then, the releasing reagent (50% AS solution containing 0.5 M glycine and 10% ammonium hydroxide at pH 10) was introduced through the AS channel to release the target protein (HSA). The retained antibody was recovered by eluting the sample channel with water at 1 ml/min. A hollow fiber membrane device at the outlet (MicroKros, Spectrum, New Brunswick, NJ, USA) was provided on-line dialysis of the eluent before fractions were collected, so that the fractions could be analyzed by SDS-PAGE (sodium dodecyl sulfate - polyacrylamide gel electrophoresis) without further dialysis. The current method does not require immobilizing the antibody onto a matrix, which is used by the conventional immunoaffinity chromatography. This method ensures full recovery of the antigen and antibody, and it may be applied to purification of other proteins.

  19. The Version 2 Global Precipitation Climatology Project (GPCP) Monthly Precipitation Analysis (1979-Present)

    NASA Technical Reports Server (NTRS)

    Adler, Robert F.; Huffman, George J.; Chang, Alfred; Ferraro, Ralph; Xie, Ping-Ping; Janowiak, John; Rudolf, Bruno; Schneider, Udo; Curtis, Scott; Bolvin, David

    2003-01-01

    The Global Precipitation Climatology Project (GPCP) Version 2 Monthly Precipitation Analysis is described. This globally complete, monthly analysis of surface precipitation at 2.5 degrees x 2.5 degrees latitude-longitude resolution is available from January 1979 to the present. It is a merged analysis that incorporates precipitation estimates from low-orbit-satellite microwave data, geosynchronous-orbit-satellite infrared data, and rain gauge observations. The merging approach utilizes the higher accuracy of the low-orbit microwave observations to calibrate, or adjust, the more frequent geosynchronous infrared observations. The data set is extended back into the premicrowave era (before 1987) by using infrared-only observations calibrated to the microwave-based analysis of the later years. The combined satellite-based product is adjusted by the raingauge analysis. This monthly analysis is the foundation for the GPCP suite of products including those at finer temporal resolution, satellite estimate, and error estimates for each field. The 23-year GPCP climatology is characterized, along with time and space variations of precipitation.

  20. The Connection Between Hurricanes and Precipitation in Maryland

    NASA Astrophysics Data System (ADS)

    Liu, J.; Liu, Z.

    2015-12-01

    Precipitation, though necessary, can affect humanity in disastrous ways. Droughts, floods and other related disasters can costly damage economy. In 2012, Hurricane Sandy, caused a total economic loss of about 65 billion and in the state of Maryland, approximately 13.55 million. The purpose of this study is to determine what, if any effect do hurricanes have on monthly and annual precipitation in Maryland. Furthermore, using this information, discussion can be made on hurricane activity in Maryland and the possible connection to global climate change. To achieve this goal, three objectives were developed to: 1) Gain a better understanding of Maryland's terrain and how that affects precipitation; 2) Calculate monthly and annual precipitation in the state; and 3) Calculate how much precipitation was contributed by each hurricane. The NASA TRMM Multi-Satellite Precipitation Analysis (TMPA) precipitation products were used. Our results show that hurricanes do significantly affect both monthly and annual precipitation in Maryland, so much so that if removed, most monthly and annual precipitations would be below their averages. The methodology could be applied to other states or regions as well. Giving the global warming scenario, it is important to understand changes of hurricane size, track and intensity since both can have significant impacts on Maryland, which warrants further studies.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  2. Precipitation-Based ENSO Indices

    NASA Technical Reports Server (NTRS)

    Adler, Robert; Curtis, Scott

    1998-01-01

    In this study gridded observed precipitation data sets are used to construct rainfall-based ENSO indices. The monthly El Nino and La Nina Indices (EI and LI) measure the steepest zonal gradient of precipitation anomalies between the equatorial Pacific and the Maritime Continent. This is accomplished by spatially averaging precipitation anomalies using a spatial boxcar filter, finding the maximum and minimum averages within a Pacific and Maritime Continent domain for each month, and taking differences. EI and LI can be examined separately or combined to produce one ENSO Precipitation Index (ESPI). ESPI is well correlated with traditional sea surface temperature and pressure indices, leading Nino 3.4. One advantage precipitation indices have over more conventional indices, is describing the strength and position of the Walker circulation. Examples are given of tracking the impact of ENSO events on the tropical precipitation fields.

  3. National Acid Precipitation Assessment Plan

    SciTech Connect

    Not Available

    1982-06-01

    The Acid Precipitation Act of 1980 (Title VII of The Energy Security Act of 1980 - P.L. 96-294) established the Interagency Task Force on Acid Precipitation to develop and implement a comprehensive National Acid Precipitation Assessment Program. The Act requires the Task Force to produce a National Plan for the ten-year research program; this document is that Plan. The purpose of the National Acid Precipitation Assessment Program is to increase our understanding of the causes and effects of acid precipitation. The National Program includes research, monitoring and assessment activities that emphasize the timely development of a firmer scientific basis for decision making. This program of policy-oriented research issues Annual Reports describing research progress and the current state of knowledge about acid precipitation and its implications. The first Annual Report to the President and the Congress was issued in January 1982.

  4. Reconciling precipitation trends in Alaska: 2. Gridded data analyses

    NASA Astrophysics Data System (ADS)

    McAfee, Stephanie; Guentchev, Galina; Eischeid, Jon

    2014-12-01

    There is a great deal of interest in whether and how Alaska's precipitation is changing but little agreement in the existing peer-reviewed literature. To provide insight on this question, we have selected three commonly used 0.5° resolution gridded precipitation products that have long-term monthly data coverage (Climatic Research Unit TS3.10.1, Global Precipitation Climatology Centre Full Data Reanalysis version 5, and University of Delaware version 2.01) and evaluated their homogeneity and trends with multiple methods over two periods, 1950-2008 and 1980-2008. All three data sets displayed common broadscale features of Alaska's precipitation climatology, but there were substantial differences between them in terms of average precipitation amount and interannual variability. Temporal inhomogeneity was a significant concern over Alaska in gridded precipitation products, as it was in the state's coastal weather stations. Although underlying station inhomogeneities were inherited to some extent by all of the gridded data sets, differences in data set construction contributed to dissimilarities in inhomogeneity, as well. There were contrasts in trends between the two time periods, and some minor discrepancies occurred as a function of the trend detection method, but the main disparities stemmed from choice of data set. Indeed, there were large areas where these data sets disagreed on both the sign and significance of precipitation trends. Until further analysis can resolve these differences, researchers using gridded precipitation data or evaluating studies based on such data should interpret results with extreme caution.

  5. Gauge Adjusted Global Satellite Mapping of Precipitation (GSMAP_GAUGE)

    NASA Astrophysics Data System (ADS)

    Mega, T.; Ushio, T.; Yoshida, S.; Kawasaki, Z.; Kubota, T.; Kachi, M.; Aonashi, K.; Shige, S.

    2013-12-01

    Precipitation is one of the most important parameters on the earth system, and the global distribution of precipitation and its change are essential data for modeling the water cycle, maintaining the ecosystem environment, agricultural production, improvements of the weather forecast precision, flood warning and so on. The GPM (Global Precipitation Measurement) project is led mainly by the United States and Japan, and is now being actively promoted in Europe, France, India, and China with international cooperation. In this project, the microwave radiometers observing microwave emission from rain will be placed on many low-orbit satellites, to reduce the interval to about 3 hours in observation time for each location on the earth. However, the problem of sampling error arises if the global precipitation estimates are less than three hours. Therefore, it is necessary to utilize a gap-filling technique to generate precipitation maps with high temporal resolution, which is quite important for operational uses such as flash flood warning systems. Global Satellite Mapping of Precipitation (GSMaP) project was established by the Japan Science and Technology Agency (JST) in 2002 to produce global precipitation products with high resolution and high precision from not only microwave radiometers but also geostationary infrared radiometers. Currently, the GSMaP_MVK product has been successfully producing fairly good pictures in near real time, and the products shows a comparable score compared with other high-resolution precipitation systems (Ushio et al. 2009 and Kubota et al. 2009). However some evaluations particularly of the operational applications show the tendency of underestimation compared to some ground based observations for the cases showing extremely high precipitation rates. This is partly because the spatial and temporal samplings of the satellite estimates are different from that of the ground based estimates. The microwave imager observes signals from

  6. 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

  7. 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

  8. Precipitation Estimation from Remotely Sensed Data Using Deep Neural Network

    NASA Astrophysics Data System (ADS)

    Tao, Y.; Gao, X.; Hsu, K. L.; Sorooshian, S.; Ihler, A.

    2015-12-01

    This research develops a precipitation estimation system from remote sensed data using state-of-the-art machine learning algorithms. Compared to ground-based precipitation measurements, satellite-based precipitation estimation products have advantages of temporal resolution and spatial coverage. Also, the massive amount of satellite data contains various measures related to precipitation formation and development. On the other hand, deep learning algorithms were newly developed in the area of machine learning