43 results on '"Limaye, Ashutosh S"'
Search Results
2. Evaluating the performance of high-resolution satellite imagery in detecting ephemeral water bodies over West Africa
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Mishra, Vikalp, Limaye, Ashutosh S., Muench, Rebekke E., Cherrington, Emil A., and Markert, Kel N.
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- 2020
- Full Text
- View/download PDF
3. Use of public Earth observation data for tracking progress in sustainable management of coastal forest ecosystems in Belize, Central America
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Cherrington, Emil A., Griffin, Robert E., Anderson, Eric R., Hernandez Sandoval, Betzy E., Flores-Anderson, Africa I., Muench, Rebekke E., Markert, Kel N., Adams, Emily C., Limaye, Ashutosh S., and Irwin, Daniel E.
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- 2020
- Full Text
- View/download PDF
4. Providing Data Access and Analysis Capabilities to SERVIR’s Data-Sparse Regions
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Ashmall, William, Limaye, Ashutosh S, Delgado, Francisco Jose, and Mayer, Timothy
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Computer Programming And Software - Abstract
In developing regions of the world, the communications infrastructure pose enormous challenges for using Earth observation data. Limited internet bandwidth along with the high costs make it almost impossible to process and extract zonal statistics over large periods of time for even small geographic areas. In such cases, downloading daily rainfall data or dekadal series of NDVI data would take days and consume all the bandwidth allocated to an organization (for reference, internet connections in Niger would cost thousands of dollars per month at a maximum - and unreliable - bandwidth of just 10 Mbps). Running crop models or hydrological models typically require several years of historic data over the area of interest (AOI). In some cases, these AOIs are relatively small compared to the footprint of individual earth observation granules. Hence, systems that let the stakeholders subset the data to download to a user specified area, or even submit processing requests that let them download small result files for the AOI become critical. The SERVIR program has developed a tool to provide this type of access to help decision makers in developing regions use long time series of adjusted rainfall data (CHIRPS), NDVI values, seasonal weather forecasts, evaporative stress indices and others in a very efficient manner. This system, named ClimateSERV (https://climateserv.servirglobal.net) ingests the datasets in an automated fashion and allows interactive access (through a web application), or automated access through a simple API that developers can quickly incorporate in independent applications. This way, the extraction of daily averages of rainfall over a 50 square Km area through 30 years of archived data takes only a few seconds to process, and the results can be presented on an online chart or downloaded in a comma separated file that's only a few Kb.
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- 2019
5. 12E.5 Forecasting Frost: Using High Resolution WRF Runs to Predict Frost Occurrence in the Tea Growing Regions of Kenya
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Adams, Emily C, Nyaga, James, Ellenburg, Walter L, Limaye, Ashutosh S, Mugo, Robinson, Flores, Africa, Irwin, Dan, Case, Jon, Malaso, Susan, and Sedah, Absea
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Earth Resources And Remote Sensing - Published
- 2019
6. Strategies, Practices, and Challenges for Interagency Co-Authorship in an International Science and Development Program
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Anderson, Eric Ross, Bolten, John D, Farrukh,Chishtie, Markert, Amanda Weigel, Mohammed, Ibrahim Nourein, Poortinga, Ate, Meechaiya, Chinaporn, Lashmi, Venkat, Srinivasan, Raghavan, Saah, David S, Markert, Kel, Matheswaran, Karthikeyan, Oddo, Perry, McDonald, Spencer, Spruce, Joseph, Towashiraporn, Peeranan, Deeprawat, Wadee, Sirichaovanichkarn, Ekapol, Limaye, Ashutosh, S, Cutting, M. Kathleen, French, Raymond, Casey, Katherine, and Irwin, Daniel
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Geosciences (General) - Published
- 2018
7. How to Leverage the Power of SAR Observations for Forest Monitoring Systems
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Kucera, Leah M, Cordova, Africa Ixmucane Flores, Thapa, Rajesh Bahadur, Herndon, Kelsey E, Saah, David, Quyen, Nguyen Hanh, Cherrington, Emil A, Muench, Rebekke, Rushi, Begum Rabeya, Adams, Emily Caitlin, Oduor, Phoebe, Limaye, Ashutosh S, and Vadrevu, Krishna
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Social And Information Sciences (General) ,Earth Resources And Remote Sensing - Abstract
Earth observations from Synthetic Aperture Radar (SAR) can provide unique observations related to forest structure and condition. Furthermore, SAR has many potential applications in forest monitoring systems, particularly where clouds have impeded optical observations. Currently, there is a reliable, freely-available, provision of SAR datasets, such as Sentinel-1, and there are plans to have more observations in the near- future (NISAR, BIOMASS). Given SAR’s enhanced earth observation characteristics, there is broad interest in using SAR datasets for decision support systems, such as deforestation early warning systems. However, applications of SAR are still underutilized. What is preventing users from using SAR data in their decision support systems? This study documents the experiences and lessons learned from the SERVIR network on the main limitations of incorporating SAR datasets into existing forest monitoring systems. This research also focuses on the major technical and scientific barriers we experience and best practices to address them. The results of this study are part of the SERVIR- SilvaCarbon collaboration. The primary goal of this collaboration is to build capacity in the applied use of SAR for forest monitoring and biomass estimation. The products of this effort aim to start closing the gap between SAR-science and forest applications. We will also present results to generate applied-ready knowledge for SAR.
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- 2018
8. SERVIR: Using Earth Observations for Improved Decision-Making in Developing Countries
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Limaye, Ashutosh S
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Geosciences (General) - Published
- 2018
9. SERVIR: Connecting Space to Village
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Limaye, Ashutosh S and Flores Cordova, Africa Ixmucan
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Earth Resources And Remote Sensing ,Meteorology And Climatology - Abstract
From space, we can view our planet in new ways. SERVIR empowers people in developing countries to use that view for gaining knowledge and insights about their environments and adaptation to a changing climate. We work with regional decision-makers to foster use of Earth observation satellite data, GIS, and predictive models for addressing water and land use, natural disasters, agricultural problems, biodiversity, and more. These tools can improve the lives, livelihoods, safety, and future of people in communities around the world.
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- 2018
10. 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?
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Xue, Xianwu, Hong, Yang, Limaye, Ashutosh S., Gourley, Jonathan J., Huffman, George J., Khan, Sadiq Ibrahim, Dorji, Chhimi, and Chen, Sheng
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- 2013
- Full Text
- View/download PDF
11. How to Address a Global Problem with Earth Observations? Developing Best Practices to Monitor Forests Around the World
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Flores Cordova, Africa I, Cherrington, Emil A, Vadrevu, Krishna, Thapa, Rajesh Bahadur, Odour, Phoebe, Mehmood, Hamid, Quyen, Nguyen Hanh, Saah, David, Yero, Kadidia, Mamane, Bako, Bartel, Paul, Limaye, Ashutosh S, French, Raymond, Irwin, Daniel, Wilson, Sylvia, Gottielb, Sasha, and Notman, Evan
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Earth Resources And Remote Sensing - Abstract
Forests represent a key natural resource, for which degradation or disturbance is directly associated to economic implications, particularly in the context of the United Nations program REDD+ in supporting national policies to fight illegal deforestation. SERVIR, a joint NASA-USAID initiative that brings Earth observations (EO) for improved environmental decision making in developing countries, works with established institutions, called SERVIR hubs, in four regions around the world. SERVIR is partnering with global programs with great experience in providing best practices in forest monitoring systems, such as SilvaCarbon and the Global Forest Observation Initiative (GFOI), to develop a capacity building plan that prioritizes user needs. Representatives from the SERVIR global network met in February 2017 with experts in the field of Synthetic Aperture Radar (SAR) for forest applications to envisage this capacity building plan that aims to leverage the state-of-the-art knowledge on remote sensing to enhance forest monitoring for user agencies in SERVIR regions.
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- 2017
12. GC13I-0857: Designing a Frost Forecasting Service for Small Scale Tea Farmers in East Africa
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Adams, Emily C, Wanjohi, James Nyaga, Ellenburg, Walter Lee, Limaye, Ashutosh S, Mugo, Robinson M, Flores Cordova, Africa Ixmucane, Irwin, Daniel, Case, Jonathan, Malaso, Susan, and Sedah, Absae
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Earth Resources And Remote Sensing - Abstract
Kenya is the third largest tea exporter in the world, producing 10% of the world's black tea. Sixty percent of this production occurs largely by small scale tea holders, with an average farm size of 1.04 acres, and an annual net income of $1,075. According to a recent evaluation, a typical frost event in the tea growing region causes about $200 dollars in losses which can be catastrophic for a small holder farm. A 72-hour frost forecast would provide these small-scale tea farmers with enough notice to reduce losses by approximately 80 USD annually. With this knowledge, SERVIR, a joint NASA-USAID initiative that brings Earth observations for improved decision making in developing countries, sought to design a frost monitoring and forecasting service that would provide farmers with enough lead time to react to and protect against a forecasted frost occurrence on their farm. SERVIR Eastern and Southern Africa, through its implementing partner, the Regional Centre for Mapping of Resources for Development (RCMRD), designed a service that included multiple stakeholder engagement events whereby stakeholders from the tea industry value chain were invited to share their experiences so that the exact needs and flow of information could be identified. This unique event allowed enabled the design of a service that fit the specifications of the stakeholders. The monitoring service component uses the MODIS Land Surface Temperature product to identify frost occurrences in near-real time. The prediction component, currently under testing, uses the 2-m air temperature, relative humidity, and 10-m wind speed from a series of high-resolution Weather Research and Forecasting (WRF) numerical weather prediction model runs over eastern Kenya as inputs into a frost prediction algorithm. Accuracy and sensitivity of the algorithm is being assessed with observations collected from the farmers using a smart phone app developed specifically to report frost occurrences, and from data shared through our partner network developed at the stakeholder engagement meeting. This presentation will illustrate the efficacy of our frost forecasting algorithm, and a way forward for incorporating these forecasts in a meaningful way to the key decision makers - the small-scale farmers of East Africa.
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- 2017
13. GC23G-1310: Investigation Into the Effects of Climate Variability and Land Cover Change on the Hydrologic System of the Lower Mekong Basin
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Markert, Kel N, Griffin, Robert, Limaye, Ashutosh S, McNider, Richard T, and Anderson, Eric R
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Meteorology And Climatology - Abstract
The Lower Mekong Basin (LMB) is an economically and ecologically important region that experiences hydrologic hazards such as floods and droughts, which can directly affect human well-being and limit economic growth and development. To effectively develop long-term plans for addressing hydrologic hazards, the regional hydrological response to climate variability and land cover change needs to be evaluated. This research aims to investigate how climate variability, specifically variations in the precipitation regime, and land cover change will affect hydrologic parameters both spatially and temporally within the LMB. The research goal is achieved by (1) modeling land cover change for a baseline land cover change scenario as well as changes in land cover with increases in forest or agriculture and (2) using projected climate variables and modeled land cover data as inputs into the Variable Infiltration Capacity (VIC) hydrologic model to simulate the changes to the hydrologic system. The VIC model outputs were analyzed against historic values to understand the relative contribution of climate variability and land cover to change, where these changes occur, and to what degree these changes affect the hydrology. This study found that the LMB hydrologic system is more sensitive to climate variability than land cover change. On average, climate variability was found to increase discharge and evapotranspiration (ET) while decreasing water storage. The change in land cover show that increasing forest area will slightly decrease discharge and increase ET while increasing agriculture area increases discharge and decreases ET. These findings will help the LMB by supporting individual country policy to plan for future hydrologic changes as well as policy for the basin as a whole.
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- 2016
14. GPM Rainfall-Based Streamflow Analyses for East Africa
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Blankenship, Clay B, Limaye, Ashutosh S, and Mitheu, Faith
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Meteorology And Climatology ,Earth Resources And Remote Sensing - Abstract
SERVIR is a joint project of NASA and US Agency for International Development (USAID). Mission is to use satellite data and geospatial technology to help developing countries manage resources, land use, and climate risks. Means to serve, in Spanish.
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- 2016
15. Transitioning Enhanced Land Surface Initialization and Model Verification Capabilities to the Kenya Meteorological Service
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Case, Jonathan L, Mungai, John, Sakwa, Vincent, Zavodsky, Bradley T, Srikishen, Jayanthi, Limaye, Ashutosh S, and Blankenship, Clay B
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Meteorology And Climatology - Published
- 2016
16. Methods for characterizing fine particulate matter using ground observations and remotely sensed data: potential use for environmental public health surveillance
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Al-Hamdan, Mohammad Z., Crosson, William L., Limaye, Ashutosh S., Rickman, Douglas L., Quattrochi, Dale A., Estes, Jr., Maurice G., Qualters, Judith R., Sinclair, Amber H., Tolsma, Dennis D., Adeniyi, Kafayat A., and Niskar, Amanda Sue
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Air quality monitoring stations -- Usage -- Environmental aspects -- Measurement -- Methods ,Air quality -- Measurement -- Environmental aspects -- Methods -- Usage ,Environmental monitoring -- Methods -- Usage -- Measurement -- Environmental aspects ,Public health -- Environmental aspects -- Usage -- Measurement -- Methods ,Environmental services industry ,Environmental issues ,Science and technology - Abstract
ABSTRACT This study describes and demonstrates different techniques for surface fitting daily environmental hazards data of particulate matter with aerodynamic diameter less than or equal to 2.5 µm ([PM.sub.2.5]) for [...]
- Published
- 2009
17. Toward Improved Land Surface Initialization in Support of Regional WRF Forecasts at the Kenya Meteorological Service (KMS)
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Case, Jonathan L, Mungai, John, Sakwa, Vincent, Kabuchanga, Eric, Zavodsky, Bradley T, and Limaye, Ashutosh S
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Meteorology And Climatology - Abstract
SPoRT/SERVIR/RCMRD/KMS Collaboration: Builds off strengths of each organization. SPoRT: Transition of satellite, modeling and verification capabilities; SERVIR‐Africa/RCMRD: International capacity-building expertise; KMS: Operational organization with regional weather forecasting expertise in East Africa. Hypothesis: Improved land‐surface initialization over Eastern Africa can lead to better temperature, moisture, and ultimately precipitation forecasts in NWP models. KMS currently initializes Weather Research and Forecasting (WRF) model with NCEP/Global Forecast System (GFS) model 0.5‐deg initial / boundary condition data. LIS will provide much higher‐resolution land‐surface data at a scale more representative to regional WRF configuration. Future implementation of real‐time NESDIS/VIIRS vegetation fraction to further improve land surface representativeness.
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- 2014
18. Toward Improved Land Surface Initialization in Support of Regional WRF Forecasts at the Kenya Meteorological Service (KMS)
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Case, Johnathan L, Mungai, John, Sakwa, Vincent, Kabuchanga, Eric, Zavodsky, Bradley T, and Limaye, Ashutosh S
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Meteorology And Climatology - Abstract
Flooding and drought are two key forecasting challenges for the Kenya Meteorological Service (KMS). Atmospheric processes leading to excessive precipitation and/or prolonged drought can be quite sensitive to the state of the land surface, which interacts with the planetary boundary layer (PBL) of the atmosphere providing a source of heat and moisture. The development and evolution of precipitation systems are affected by heat and moisture fluxes from the land surface, particularly within weakly-sheared environments such as in the tropics and sub-tropics. These heat and moisture fluxes during the day can be strongly influenced by land cover, vegetation, and soil moisture content. Therefore, it is important to represent the land surface state as accurately as possible in land surface and numerical weather prediction (NWP) models. Enhanced regional modeling capabilities have the potential to improve forecast guidance in support of daily operations and high-impact weather over eastern Africa. KMS currently runs a configuration of the Weather Research and Forecasting (WRF) NWP model in real time to support its daily forecasting operations, making use of the NOAA/National Weather Service (NWS) Science and Training Resource Center's Environmental Modeling System (EMS) to manage and produce the KMS-WRF runs on a regional grid over eastern Africa. Two organizations at the NASA Marshall Space Flight Center in Huntsville, AL, SERVIR and the Shortterm Prediction Research and Transition (SPoRT) Center, have established a working partnership with KMS for enhancing its regional modeling capabilities through new datasets and tools. To accomplish this goal, SPoRT and SERVIR is providing enhanced, experimental land surface initialization datasets and model verification capabilities to KMS as part of this collaboration. To produce a land-surface initialization more consistent with the resolution of the KMS-WRF runs, the NASA Land Information System (LIS) is run at a comparable resolution to provide real-time, daily soil initialization data in place of data interpolated from the National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) model soil moisture and temperature fields. Additionally, realtime green vegetation fraction (GVF) data from the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi National Polar-orbiting Partnership (Suomi- NPP) satellite will be incorporated into the KMS-WRF runs, once it becomes publicly available from the National Environmental Satellite Data and Information Service (NESDIS). Finally, model verification capabilities will be transitioned to KMS using the Model Evaluation Tools (MET; Brown et al. 2009) package in conjunction with a dynamic scripting package developed by SPoRT (Zavodsky et al. 2014), to help quantify possible improvements in simulated temperature, moisture and precipitation resulting from the experimental land surface initialization. Furthermore, the transition of these MET tools will enable KMS to monitor model forecast accuracy in near real time. This paper presents preliminary efforts to improve land surface model initialization over eastern Africa in support of operations at KMS. The remainder of this extended abstract is organized as follows: The collaborating organizations involved in the project are described in Section 2; background information on LIS and the configuration for eastern Africa is presented in Section 3; the WRF configuration used in this modeling experiment is described in Section 4; sample experimental WRF output with and without LIS initialization data are given in Section 5; a summary is given in Section 6 followed by acknowledgements and references.
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- 2014
19. Toward Improved Land Surface Initialization in Support of Regional WRF Forecasts at the Kenya Meteorological Department
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Case. Jonathan, Mungai, John, Sakwa, Vincent, Kabuchanga, Eric, Zavodsky, Bradley T, and Limaye, Ashutosh S
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Meteorology And Climatology - Abstract
Flooding and drought are two key forecasting challenges for the Kenya Meteorological Department (KMD). Atmospheric processes leading to excessive precipitation and/or prolonged drought can be quite sensitive to the state of the land surface, which interacts with the boundary layer of the atmosphere providing a source of heat and moisture. The development and evolution of precipitation systems are affected by heat and moisture fluxes from the land surface within weakly-sheared environments, such as in the tropics and sub-tropics. These heat and moisture fluxes during the day can be strongly influenced by land cover, vegetation, and soil moisture content. Therefore, it is important to represent the land surface state as accurately as possible in numerical weather prediction models. Enhanced regional modeling capabilities have the potential to improve forecast guidance in support of daily operations and high-end events over east Africa. KMD currently runs a configuration of the Weather Research and Forecasting (WRF) model in real time to support its daily forecasting operations, invoking the Nonhydrostatic Mesoscale Model (NMM) dynamical core. They make use of the National Oceanic and Atmospheric Administration / National Weather Service Science and Training Resource Center's Environmental Modeling System (EMS) to manage and produce the WRF-NMM model runs on a 7-km regional grid over eastern Africa. Two organizations at the National Aeronautics and Space Administration Marshall Space Flight Center in Huntsville, AL, SERVIR and the Short-term Prediction Research and Transition (SPoRT) Center, have established a working partnership with KMD for enhancing its regional modeling capabilities. To accomplish this goal, SPoRT and SERVIR will provide experimental land surface initialization datasets and model verification capabilities to KMD. To produce a land-surface initialization more consistent with the resolution of the KMD-WRF runs, the NASA Land Information System (LIS) will be run at a comparable resolution to provide real-time, daily soil initialization data in place of interpolated Global Forecast System soil moisture and temperature data. Additionally, real-time green vegetation fraction data from the Visible Infrared Imaging Radiometer Suite will be incorporated into the KMD-WRF runs, once it becomes publicly available from the National Environmental Satellite Data and Information Service. Finally, model verification capabilities will be transitioned to KMD using the Model Evaluation Tools (MET) package, in order to quantify possible improvements in simulated temperature, moisture and precipitation resulting from the experimental land surface initialization. The transition of these MET tools will enable KMD to monitor model forecast accuracy in near real time. This presentation will highlight preliminary verification results of WRF runs over east Africa using the LIS land surface initialization.
- Published
- 2014
20. Parameter sensitivity of soil moisture retrievals from airborne C- and X-band radiometer measurements in SMEX02
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Crosson, William L., Limaye, Ashutosh S., and Laymon, Charles A.
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Algorithms -- Usage ,Soil moisture -- Research ,Parameter estimation -- Methods ,Sensors -- Usage ,Algorithm ,Business ,Earth sciences ,Electronics and electrical industries - Abstract
Among passive microwave frequencies, sensors operating at C- and X-band frequencies have been used with some success to estimate near-surface soil moisture from aircraft and satellite platforms. The objective of this paper is to quantify the sensitivities of soil moisture retrieved via a single-channel single-polarization algorithm to the observed brightness temperature and to retrieval algorithm parameters of surface roughness, vegetation B parameter, and single-scattering albedo. Examination of the regions within the parameter space that produce accurate soil moisture retrievals reveals that reasonably accurate retrievals can be made over a range of conditions using a fixed set of input parameters. Retrievals with horizontally polarized brightness temperature observations are more consistent than with vertically polarized observations. At horizontal polarization, sensitivity to the input parameters is much greater for wet soils than for dry soils, whereas for vertical polarization the moisture dependence is much weaker. At vertical polarization, sensitivities to variations in all parameters are much lower. To ensure that retrieval accuracy specifications are consistently met, high soil moisture conditions should be used in defining parameter accuracy requirements. Given the spatial and temporal variability of vegetation and soil conditions, it seems unlikely that, for regions with substantial rapidly growing vegetation, the accuracy requirements for model parameters in a single-frequency, single-polarization retrieval algorithm can be met with current satellite products. For such conditions, any soil moisture retrieval algorithm using parameterizations similar to those of this study may require multiple frequencies, polarizations, or look angles to produce stable, reliable soil moisture estimates. Index Terms--Microwave radiometry, parameter space methods, sensitivity, Soil Moisture Experiments in 2002 (SMEX02), soil moisture, vegetation.
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- 2005
21. Parameter sensitivity of soil moisture retrievals from airborne L-band radiometer measurements in SMEX02
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Crosson, William L., Limaye, Ashutosh S., and Laymon, Charles A.
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Soil moisture -- Research ,Algorithms -- Research ,Algorithms -- Technology application ,Radiation -- Measurement ,Radiation -- Research ,Algorithm ,Technology application ,Business ,Earth sciences ,Electronics and electrical industries - Abstract
Over the past two decades, successful estimation of soil moisture has been accomplished using L-band microwave radiometer data. However, remaining uncertainties related to surface roughness and the absorption, scattering, and emission by vegetation must be resolved before soil moisture retrieval algorithms can be applied with known and acceptable accuracy using satellite observations. Surface characteristics are highly variable in space and time, and there has been little effort made to determine the parameter estimation accuracies required to meet a given soil moisture retrieval accuracy specification. This study quantifies the sensitivities of soil moisture retrieved using an L-band single-polarization algorithm to three land surface parameters for corn and soybean sites in Iowa, United States. Model sensitivity to the input parameters was found to be much greater when soil moisture is high. For even moderately wet soils, extremely high sensitivity of retrieved soil moisture to some model parameters for corn and soybeans caused the retrievals to be unstable. Parameter accuracies required for consistent estimation of soil moisture in mixed agricultural areas within retrieval algorithm specifications are estimated. Given the spatial and temporal variability of vegetation and soil conditions for agricultural regions it seems unlikely that, for the single-frequency, single-polarization retrieval algorithm used in this analysis, the parameter accuracy requirements can be met with current satellite-based land surface products. We conclude that for regions with substantial vegetation, particularly where the vegetation is changing rapidly, any soil moisture retrieval algorithm that is based on the physics and parameterizations used in this study will require multiple frequencies, polarizations, or look angles to produce stable, reliable soil moisture estimates. Index Terms--Microwave radiometry, parameter space methods, sensitivity, soil moisture, vegetation.
- Published
- 2005
22. SERVIR Town Hall - Connecting Space to Village
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Limaye, Ashutosh S, Searby, Nancy D, Irwin, Daniel, and Albers, Cerese
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Earth Resources And Remote Sensing - Abstract
SERVIR, a joint NASA-USAID project, strives to improve environmental decision making through the use of Earth observations, models, and geospatial technology innovations. SERVIR connects these assets with the needs of end users in Mesoamerica, East Africa, and Hindu Kush-Himalaya regions. This Town Hall meeting will engage the AGU community by exploring examples of connecting Space to Village with SERVIR science applications.
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- 2013
23. SERVIR and Public Health
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Moreno-Madrinan, Max J, Limaye, Ashutosh S, Khan, Maudood N, Crosson, William L, and Irwin, Daniel E
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Earth Resources And Remote Sensing - Abstract
Servir is a NASA-USAID partnership to improve environmental management and resilience to climate change by strengthening the capacity of governments and other key stakeholders to integrate Earth observations into development decision-making
- Published
- 2012
24. Cloud Computing Applications in Support of Earth Science Activities at Marshall Space Flight Center
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Molthan, Andrew L, Limaye, Ashutosh S, and Srikishen, Jayanthi
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Meteorology And Climatology - Abstract
Currently, the NASA Nebula Cloud Computing Platform is available to Agency personnel in a pre-release status as the system undergoes a formal operational readiness review. Over the past year, two projects within the Earth Science Office at NASA Marshall Space Flight Center have been investigating the performance and value of Nebula s "Infrastructure as a Service", or "IaaS" concept and applying cloud computing concepts to advance their respective mission goals. The Short-term Prediction Research and Transition (SPoRT) Center focuses on the transition of unique NASA satellite observations and weather forecasting capabilities for use within the operational forecasting community through partnerships with NOAA s National Weather Service (NWS). SPoRT has evaluated the performance of the Weather Research and Forecasting (WRF) model on virtual machines deployed within Nebula and used Nebula instances to simulate local forecasts in support of regional forecast studies of interest to select NWS forecast offices. In addition to weather forecasting applications, rapidly deployable Nebula virtual machines have supported the processing of high resolution NASA satellite imagery to support disaster assessment following the historic severe weather and tornado outbreak of April 27, 2011. Other modeling and satellite analysis activities are underway in support of NASA s SERVIR program, which integrates satellite observations, ground-based data and forecast models to monitor environmental change and improve disaster response in Central America, the Caribbean, Africa, and the Himalayas. Leveraging SPoRT s experience, SERVIR is working to establish a real-time weather forecasting model for Central America. Other modeling efforts include hydrologic forecasts for Kenya, driven by NASA satellite observations and reanalysis data sets provided by the broader meteorological community. Forecast modeling efforts are supplemented by short-term forecasts of convective initiation, determined by geostationary satellite observations processed on virtual machines powered by Nebula.
- Published
- 2011
25. Proposed Use of the NASA Ames Nebula Cloud Computing Platform for Numerical Weather Prediction and the Distribution of High Resolution Satellite Imagery
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Limaye, Ashutosh S, Molthan, Andrew L, and Srikishen, Jayanthi
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Meteorology And Climatology - Abstract
The development of the Nebula Cloud Computing Platform at NASA Ames Research Center provides an open-source solution for the deployment of scalable computing and storage capabilities relevant to the execution of real-time weather forecasts and the distribution of high resolution satellite data to the operational weather community. Two projects at Marshall Space Flight Center may benefit from use of the Nebula system. The NASA Short-term Prediction Research and Transition (SPoRT) Center facilitates the use of unique NASA satellite data and research capabilities in the operational weather community by providing datasets relevant to numerical weather prediction, and satellite data sets useful in weather analysis. SERVIR provides satellite data products for decision support, emphasizing environmental threats such as wildfires, floods, landslides, and other hazards, with interests in numerical weather prediction in support of disaster response. The Weather Research and Forecast (WRF) model Environmental Modeling System (WRF-EMS) has been configured for Nebula cloud computing use via the creation of a disk image and deployment of repeated instances. Given the available infrastructure within Nebula and the "infrastructure as a service" concept, the system appears well-suited for the rapid deployment of additional forecast models over different domains, in response to real-time research applications or disaster response. Future investigations into Nebula capabilities will focus on the development of a web mapping server and load balancing configuration to support the distribution of high resolution satellite data sets to users within the National Weather Service and international partners of SERVIR.
- Published
- 2010
26. Exploiting Satellite Remote-Sensing Data in Fine Particulate Matter Characterization for Serving the Environmental Public Health Tracking Network (EPHTN): The HELIX-Atlanta Experience and NPOESS Implications
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Al-Hamdan, Mohammad Z, Crosson, William L, Limaye, Ashutosh S, Rickman, Douglas L, Quattrochi, Dale A, Estes, Maurice G, Qualters, Judith R, Sinclair, Amber H, Tolsma, Dennis D, and Adeniyi, Kafayat A
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Earth Resources And Remote Sensing - Abstract
As part of the U.S. National Environmental Public Health Tracking Network (EPHTN), the National Center for Environmental Health (NCEH) at the U.S. Centers for Disease Control and Prevention (CDC) led a project in collaboration with the National Aeronautics and Space Administration (NASA) Marshall Space Flight Center (MSFC) called Health and Environment Linked for Information Exchange (HELIX-Atlanta). Under HELIX-Atlanta, pilot projects were conducted to develop methods to better characterize exposure; link health and environmental datasets; and analyze spatial/temporal relationships. This paper describes and demonstrates different techniques for surfacing daily environmental hazards data of particulate matter with aerodynamic diameter less than or equal to 2.5 micrometers (PM(sub 2.5) for the purpose of integrating respiratory health and environmental data for the CDC's pilot study of HELIX-Atlanta. It describes a methodology for estimating ground-level continuous PM(sub 2.5) concentrations using spatial surfacing techniques and leveraging NASA Moderate Resolution Imaging Spectrometer (MODIS) data to complement the U.S. Environmental Protection Agency (EPA) ground observation data. The study used measurements of ambient PM(sub 2.5) from the EPA database for the year 2003 as well as PM(sub 2.5) estimates derived from NASA's MODIS data. Hazard data have been processed to derive the surrogate exposure PM(sub 2.5) estimates. The paper has shown that merging MODIS remote sensing data with surface observations of PM(sub 2.5), may provide a more complete daily representation of PM(sub 2.5), than either data set alone would allow, and can reduce the errors in the PM(sub 2.5) estimated surfaces. Future work in this area should focus on combining MODIS column measurements with profile information provided by satellites like the National Polar-orbiting Operational Environmental Satellite System (NPOESS). The Visible Infrared Imager/Radiometer Suite (VIIRS) and the Aerosol Polarimeter Sensor (APS) NPOESS sensors will provide first-order information on aerosol particle size and are anticipated to provide information on aerosol products at higher resolution and accuracy than MODIS. Use of the NPOESS remote sensing data should result in more robust remotely sensed data that can be coupled with the methods discussed in this paper to generate surface concentrations of PM(2.5) for linkage with health data in Environmental Public Health Tracking.
- Published
- 2008
27. The Use of GIS and Remotely Sensed Data in Environmental Public Health Tracking (EPHT): The HELIX-Atlanta Experience
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Al-Hamdan, Mohammad Z, Crosson, William L, Limaye, Ashutosh S, Estes, Maurice G., Jr, Watts, Carol, Rickman, Douglas L, Quattrochi, Dale A, Qualters, Judith R, Sinclair, Amber H, Tolsma, Dennis D, and Adeniyi, Kafayat A
- Subjects
Earth Resources And Remote Sensing - Abstract
As part of the National Environmental Public Health Tracking Network (EPHTN), the National Center for Environmental Health (NCEH) at the Centers for Disease Control and Prevention (CDC) is leading a project in collaboration with the NASA Marshall Space Flight Center (NASA/MSFC) called Health and Environment Linked for Information Exchange (HELIX-Atlanta). HELIX-Atlanta's goal is to examine the feasibility of building an integrated electronic health and environmental data network in five counties of metropolitan Atlanta, GA. Under HELIX-Atlanta, pilot projects are being conducted to develop methods to characterize exposure; link health and environmental data; analyze the relationship between health and environmental factors; and communicate findings. There is evidence in the research literature that asthmatic persons are at increased risk of developing asthma exacerbations with exposure to environmental factors, including PM(sub 2.5). Thus, HELIX-Atlanta is focusing on methods for characterizing population exposure to PM(sub 2.5) for the Atlanta metropolitan area that could be used in ongoing surveillance. NASA/MSFC is working with CDC to combine NASA earth science satellite observations related to air quality and environmental monitoring data to model surface estimates of fine particulate matter (PM(sub 2.5)) concentrations in a Geographic Information System (GIS) that can be linked with clinic visits for asthma on the aggregated grid level as well as the individual level at the geographic locations of the patients' residences.
- Published
- 2007
28. Methods for Characterizing Fine Particulate Matter Using Satellite Remote-Sensing Data and Ground Observations: Potential Use for Environmental Public Health Surveillance
- Author
-
Al-Hamdan, Mohammad Z, Crosson, William L, Limaye, Ashutosh S, Rickman, Douglas L, Quattrochi, Dale A, Estes, Maurice G, Qualters, Judith R, Niskar, Amanda S, Sinclair, Amber H, Tolsma, Dennis D, and Adeniyi, Kafayat A
- Subjects
Earth Resources And Remote Sensing - Abstract
This study describes and demonstrates different techniques for surfacing daily environmental / hazards data of particulate matter with aerodynamic diameter less than or equal to 2.5 micrometers (PM2.5) for the purpose of integrating respiratory health and environmental data for the Centers for Disease Control and Prevention (CDC s) pilot study of Health and Environment Linked for Information Exchange (HELIX)-Atlanta. It described a methodology for estimating ground-level continuous PM2.5 concentrations using B-Spline and inverse distance weighting (IDW) surfacing techniques and leveraging National Aeronautics and Space Administration (NASA) Moderate Resolution Imaging Spectrometer (MODIS) data to complement The Environmental Protection Agency (EPA) ground observation data. The study used measurements of ambient PM2.5 from the EPA database for the year 2003 as well as PM2.5 estimates derived from NASA s satellite data. Hazard data have been processed to derive the surrogate exposure PM2.5 estimates. The paper has shown that merging MODIS remote sensing data with surface observations of PM2.5 not only provides a more complete daily representation of PM2.5 than either data set alone would allow, but it also reduces the errors in the PM2.5 estimated surfaces. The results of this paper have shown that the daily IDW PM2.5 surfaces had smaller errors, with respect to observations, than those of the B-Spline surfaces in the year studied. However the IDW mean annual composite surface had more numerical artifacts, which could be due to the interpolating nature of the IDW that assumes that the maxima and minima can occur only at the observation points. Finally, the methods discussed in this paper improve temporal and spatial resolutions and establish a foundation for environmental public health linkage and association studies for which determining the concentrations of an environmental hazard such as PM2.5 with good accuracy levels is critical.
- Published
- 2007
29. Simulation of Urban Heat Island Mitigation Strategies in Atlanta, GA Using High-Resolution Land Use/Land Cover Data Set to Enhance Meteorological Modeling
- Author
-
Crosson, William L, Dembek, Scott, Estes, Maurice G., Jr, Limaye, Ashutosh S, Lapenta, William, Quattrochi, Dale A, Johnson, Hoyt, and Khan, Maudood
- Subjects
Meteorology And Climatology - Abstract
The specification of land use/land cover (LULC) and associated land surface parameters in meteorological models at all scales has a major influence on modeled surface energy fluxes and boundary layer states. In urban areas, accurate representation of the land surface may be even more important than in undeveloped regions due to the large heterogeneity within the urban area. Deficiencies in the characterization of the land surface related to the spatial or temporal resolution of the data, the number of LULC classes defined, the accuracy with which they are defined, or the degree of heterogeneity of the land surface properties within each class may degrade the performance of the models. In this study, an experiment was conducted to test a new high-resolution LULC data set for meteorological simulations for the Atlanta, Georgia metropolitan area using a mesoscale meteorological model and to evaluate the effects of urban heat island (UHI) mitigation strategies on modeled meteorology for 2030. Simulation results showed that use of the new LULC data set reduced a major deficiency of the land use data used previously, specifically the poor representation of urban and suburban land use. Performance of the meteorological model improved substantially, with the overall daytime cold bias reduced by over 30%. UHI mitigation strategies were projected to offset much of a predicted urban warming between 2000 and 2030. In fact, for the urban core, the cooling due to UHI mitigation strategies was slightly greater than the warming associated with urbanization over this period. For the larger metropolitan area, cooling only partially offset the projected warming trend.
- Published
- 2006
30. Economic Impact of Water Allocation on Agriculture in the Lower Chattahoochee River Basin
- Author
-
Limaye, Ashutosh S, Paudel, Krishna P, Musleh, Fuad, Cruise, James F, and Hatch, L. Upton
- Subjects
Earth Resources And Remote Sensing - Abstract
The relative value of irrigation water was assessed for three important crops (corn, cotton, and peanuts) grown in the southeastern United States. A decision tool was developed with the objective of allocating limited available water among competing crops in a manner that would maximize the economic returns to the producers. The methodology was developed and tested for a hypothetical farm located in Henry County, Alabama in the Chattahoochee river basin. Crop yield - soil moisture response functions were developed using Monte Carlo simulated data for cotton, corn, and peanuts. A hydrologic model was employed to simulate runoff over the period of observed rainfall the county to provide inflows to storage facilities that could be used as constraints for the optimal allocation of the available water in the face of the uncertainty of future rainfall and runoff. Irrigation decisions were made on a weekly basis during the critical water deficit period in the region. An economic optimization model was employed with the crop responses, and soil moisture functions to determine the optimum amount of water place on each crop subject to the amount of irrigation water availability and climatic uncertainty. The results indicated even small amounts of irrigation could significantly benefit farmers in the region if applied judiciously. A weekly irrigation sequence was developed that maintained the available water on the crops that exhibited the most significant combination of water sensitivity and cash value.
- Published
- 2004
31. Landcover Based Optimal Deconvolution of PALS L-band Microwave Brightness Temperature
- Author
-
Limaye, Ashutosh S, Crosson, William L, Laymon, Charles A, and Njoku, Eni G
- Subjects
Earth Resources And Remote Sensing - Abstract
An optimal de-convolution (ODC) technique has been developed to estimate microwave brightness temperatures of agricultural fields using microwave radiometer observations. The technique is applied to airborne measurements taken by the Passive and Active L and S band (PALS) sensor in Iowa during Soil Moisture Experiments in 2002 (SMEX02). Agricultural fields in the study area were predominantly soybeans and corn. The brightness temperatures of corn and soybeans were observed to be significantly different because of large differences in vegetation biomass. PALS observations have significant over-sampling; observations were made about 100 m apart and the sensor footprint extends to about 400 m. Conventionally, observations of this type are averaged to produce smooth spatial data fields of brightness temperatures. However, the conventional approach is in contrast to reality in which the brightness temperatures are in fact strongly dependent on landcover, which is characterized by sharp boundaries. In this study, we mathematically de-convolve the observations into brightness temperature at the field scale (500-800m) using the sensor antenna response function. The result is more accurate spatial representation of field-scale brightness temperatures, which may in turn lead to more accurate soil moisture retrieval.
- Published
- 2004
32. Performance evaluation of soil moisture profile estimation through entropy-based and exponential filter models.
- Author
-
Mishra, Vikalp, Ellenburg, W. Lee, Markert, Kel N., and Limaye, Ashutosh S.
- Subjects
SOIL moisture ,SOIL profiles ,MAXIMUM entropy method ,STANDARD deviations ,FILTERS & filtration - Abstract
In this study we analyzed two models commonly used in remote sensing-based root-zone soil moisture (SM) estimations: one utilizing the exponential decaying function and the other derived from the principle of maximum entropy (POME). We used both models to deduce root-zone (0–100 cm) SM conditions at 11 sites located in the southeastern USA for the period 2012–2017 and evaluated the strengths and weaknesses of each approach against ground observations. The results indicate that, temporally, at shallow depths (10 cm), both models performed similarly, with correlation coefficients (r) of 0.89 (POME) and 0.88 (exponential). However, with increasing depths, the models start to deviate: at 50 cm the POME resulted in r of 0.93 while the exponential filter (EF) model had r of 0.58. Similar trends were observed for unbiased root mean square error (ubRMSE) and bias. Vertical profile analysis suggests that, overall, the POME model had nearly 30% less ubRMSE compared to the EF model, indicating that the POME model was relatively better able to distribute the moisture content through the soil column. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
33. Linking Health and Environmental Data���in a Public Health Surveillance System
- Author
-
Rickman, Doug, Niskar, Amanda Sue, Quattrochi, Dale, Estes, Maurice G, Limaye, Ashutosh S., Crosson, William L., and Al-Hamdan, Mohammad Z
- Published
- 2005
- Full Text
- View/download PDF
34. AN APPLICATION OF THE PHOSPHORUS CONSISTENT RULE FOR ENVIRONMENTALLY ACCEPTABLE COST-EFFICIENT MANAGEMENT OF BROILER LITTER IN CROP PRODUCTION
- Author
-
Paudel, Krishna P., Limaye, Ashutosh S, Adhikari, Murali, and Martin, Neil R.
- Subjects
Production Economics ,Environmental Economics and Policy - Abstract
We calculated the profitability of using broiler litter as a source of plant nutrients using the phosphorus consistent litter application rule. The cost saving by using litter is 37% over the use of chemical fertilizer alone to meet the nutrient needs of major crops grown in Alabama. In the optimal solution, only a few routes of all the possible routes developed were used for inter- and intra- county litter hauling. If litter is not adopted as the sole source of crop nutrients, the best environmental policy may be to pair the phosphorus consistent rule with taxes, marketable permits, and subsidies.
- Published
- 2002
- Full Text
- View/download PDF
35. Effects of noise on optimal deconvolution accuracy in microwave observations.
- Author
-
Limaye, Ashutosh S., Crosson, William L., and Laymon, Charles A.
- Subjects
- *
MICROWAVE measurements , *ECOLOGICAL heterogeneity , *WATER temperature , *SOIL moisture measurement , *GEOPHYSICAL observatories , *SURFACE energy - Abstract
Due to large footprints of remotely sensed microwave brightness temperatures, accuracy of microwave observations in areas of large surface heterogeneity has always been a technological challenge. Microwave observations in areas dominated by waterbodies typically exhibit observed brightness temperature several tens of kelvins lower than areas having no surface water. The non-linearity between brightness temperature and other geophysical quantities such as soil moisture makes the accuracy of microwave observations a critical element for accurate estimation of these quantities. In retrieving soil moisture estimates, an error of 1 K in remotely sensed microwave brightness temperatures results in about 0.5–1% error in volumetric soil moisture. Large uncertainties in the observed brightness temperatures make such observations unusable in areas of large brightness temperature contrast. In this article, we discuss a deconvolution method to improve accuracy using the overlap in the adjacent microwave observations. We have shown that the method results in improved accuracy of 40% in brightness temperature estimation in regions of high brightness temperature contrast. [ABSTRACT FROM PUBLISHER]
- Published
- 2013
- Full Text
- View/download PDF
36. Impacts of Spatial Scaling Errors on Soil Moisture Retrieval Accuracy at L-Band.
- Author
-
Crosson, William L., Limaye, Ashutosh S., and Laymon, Charles A.
- Published
- 2010
- Full Text
- View/download PDF
37. Estimating accuracy in optimal deconvolution of synthetic AMSR-E observations
- Author
-
Limaye, Ashutosh S., Crosson, William L., and Laymon, Charles A.
- Subjects
- *
ELECTRIC equipment , *ANTHROPOMETRY , *BRIGHTNESS temperature , *PHYSICAL geography - Abstract
Abstract: Optimal deconvolution (ODC) utilizes the footprint overlap in microwave observations to estimate the earth''s brightness temperatures (T B). This paper examines the accuracy of ODC-estimated T B compared with a standard averaging technique. Because brightness temperatures cannot be independently verified, we constructed synthetic True T B for accuracy assessment. We assigned T B at a high spatial resolution (1 km) grid and computed the True T B by spatial averaging of the assigned T B to a lower resolution earth grid (25 km), selected to match the resolution of products generated from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E). We used the sensor antenna response function along with the 1-km assigned T B to generate synthetic observations at AMSR-E footprint locations. These synthetic observations were subsequently deconvolved in the ODC technique to estimate T B at the lower resolution earth grid. The ODC-estimated T B and the simple grid cell averages of the synthetic observations were compared with the True T B allowing us to quantify the efficacy of each technique. In areas of high T B contrast (such as boundaries of water bodies), ODC performed significantly better than averaging. In other areas, ODC and averaging techniques produced similar results. A technique similar to ODC can be effective in delineating water bodies with significant clarity. That will allow microwave observations to be utilized near the shorelines, a trouble spot for the currently used averaging techniques. [Copyright &y& Elsevier]
- Published
- 2006
- Full Text
- View/download PDF
38. DEVELOPMENT OF AN OPTIMAL WATER ALLOCATION DECISION TOOL FOR THE MAJOR CROPS DURING THE WATER DEFICIT PERIOD IN THE SOUTHEAST UNITED STATES.
- Author
-
Paudel, Krishna P., Limaye, Ashutosh S., Hatch, L. Upton, Cruise, James F., and Musleh, Fuad
- Subjects
WATER in agriculture ,MATHEMATICAL models ,RESEARCH ,SIMULATION methods & models ,PLANT fibers ,GOVERNMENT policy ,SOIL moisture ,SOIL infiltration - Abstract
We developed a dynamic economic model to optimize irrigation water allocations during water deficit periods for three major crops grown in the humid southeastern United States. Analysis involved the use of crop simulation models to capture (a) the yield water relationship and (b) soil moisture dynamics from one week to another week. A hydrological model was used to find the water supply; combinations of hydrological and simulation models were used to find the optimal water allocation during each week in corn, cotton and peanuts. Results indicated that farmers should irrigate the most valuable crop first (peanuts) before applying water to other crops (corn and cotton). Results also showed that, because of restriction on total water supply, an increase in crop acreage did not increase the net revenue of the farm in a proportionate amount. Results should provide guidelines to water managers, engineers, policy makers, and farmers regarding an optimal amount of water allocation that will maximize net returns when water shortage is a serious concern. [ABSTRACT FROM AUTHOR]
- Published
- 2005
39. Land cover-based optimal deconvolution of PALS L-band microwave brightness temperatures
- Author
-
Limaye, Ashutosh S., Crosson, William L., Laymon, Charles A., and Njoku, Eni G.
- Subjects
- *
MICROWAVES , *TEMPERATURE , *SOIL moisture , *SOYBEAN - Abstract
An optimal deconvolution (ODC) technique has been developed to estimate microwave brightness temperatures of agricultural fields using microwave radiometer observations. The technique is applied to airborne measurements taken by the Passive and Active L and S band (PALS) sensor in Iowa during Soil Moisture Experiments in 2002 (SMEX02). Agricultural fields in the study area were predominantly soybeans and corn. The brightness temperatures of corn and soybeans were observed to be significantly different because of large differences in vegetation biomass. PALS observations have significant over-sampling; observations were made about 100 m apart and the sensor footprint extends to about 400 m. Conventionally, observations of this type are averaged to produce smooth spatial data fields of brightness temperatures. However, the conventional approach is in contrast to reality in which the brightness temperatures are in fact strongly dependent on land cover, which is characterized by sharp boundaries. In this study, we mathematically deconvolve the observations into brightness temperature at the field scale (500–800 m) using the sensor antenna response function. The result is more accurate spatial representation of field-scale brightness temperatures, which may in turn lead to more accurate soil moisture retrieval. [Copyright &y& Elsevier]
- Published
- 2004
- Full Text
- View/download PDF
40. MACROSCALE HYDROLOGIC MODELING FOR REGIONAL CLIMATE ASSESSMENT STUDIES IN THE SOUTHEASTERN UMTED STATES.
- Author
-
Limaye, Ashutosh S., Boyington, T Matthew, Cruise, James F, Bulusu, Anupama, and Brown, Elizabeth
- Abstract
BSTRACT: A macroscale hydrologic model is developed for regional climate assessment studies under way in the southeastern United States. The hydrologic modeling strategy is developed to optimize spatial representation of basin characteristics while maximizing computational efficiency. The model employs the 'grouped response unit' methodology, which follows the natural drainage pattern of the area. First order streams are delineated and their surface characteristics are tested so that areas with statistically similar characteristics can be combined into larger computational zones for modeling purposes. Hydrologic response units (HRU) are identified within the modeling units and a simple three-layer water balance model, Soil and Water Assessment Tool (SWAT), is executed for each HRU. The runoff values are then convoluted using a triangular unit hydrograph and routed by Muskingum-Cunge method. The methodology is shown to produce accurate results relative to other studies, when compared to observations. The model is used to evaluate the potential error in hydrologic assessments when using GCM predictions as climatic input in a rainfall-runoff dominated environment. In such areas, the results from this study, although limited in temporal and spatial scope, appear to imply that use of GCM climate predictions in short term quantitative analyses studies in rainfall-runoff dominated environments should proceed with caution. [ABSTRACT FROM AUTHOR]
- Published
- 2001
- Full Text
- View/download PDF
41. ASSESSMENT OF IMPACTS OF CLIMATE CHANGE ON WATER QUALITY IN THE SOUTHEASTERN UNITED STATES.
- Author
-
Cruise, James F., Limaye, Ashutosh S., and Al-Abed, Nassim
- Abstract
BSTRACT: An assessment of current and future water quality conditions in the southeastern United States has been conducted using the EPA BASINS GIS/database system. The analysis has been conducted for dissolved oxygen, total nitrate nitrogen and pH. Future streamflow conditions have been predicted for the region based on the United Kingdom Hadley Center climate model. Thus far, the analyses have been conducted at a fairly coarse spatial scale due to time and resource limitations. Two hydrologic modeling techniques have been employed in future streamflow prediction: a regional stochastic approach and the application of a physically based soil moisture model. The regional model has been applied to the entire area while the physically based model is being used at selected locations to enhance and support the stochastic model. The results of the study reveal that few basins in the southeast exhibit dissolved oxygen problems, but that several watersheds exhibit high nitrogen levels. These basins are located in regions of intense agricultural activity or in proximity to the gulf coast. In many of these areas, streamflow is projected to decline over the next 30-50 years, thus exacerbating these water quality problems. [ABSTRACT FROM AUTHOR]
- Published
- 1999
- Full Text
- View/download PDF
42. Detecting Desert Locust Breeding Grounds: A Satellite-Assisted Modeling Approach.
- Author
-
Ellenburg, W. Lee, Mishra, Vikalp, Roberts, Jason B., Limaye, Ashutosh S., Case, Jonathan L., Blankenship, Clay B., Cressman, Keith, and Mishra, Deepak R.
- Subjects
DESERT locust ,MATING grounds ,SOIL moisture ,SOIL texture ,LOCUSTS - Abstract
The objective of this study is to evaluate the ability of soil physical characteristics (i.e., texture and moisture conditions) to better understand the breeding conditions of desert locust (DL). Though soil moisture and texture are well-known and necessary environmental conditions for DL breeding, in this study, we highlight the ability of model-derived soil moisture estimates to contribute towards broader desert locust monitoring activities. We focus on the recent DL upsurge in East Africa from October 2019 though June 2020, utilizing known locust observations from the United Nations Food and Agriculture Organization (FAO). We compare this information to results from the current literature and combine the two datasets to create "optimal thresholds" of breeding conditions. When considering the most optimal conditions (all thresholds met), the soil texture combined with modeled soil moisture content predicted the estimated DL egg-laying period 62.5% of the time. Accounting for the data errors and uncertainties, a 3 × 3 pixel buffer increased this to 85.2%. By including soil moisture, the areas of optimal egg laying conditions decreased from 33% to less than 20% on average. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
43. AltEx: An open source web application and toolkit for accessing and exploring altimetry datasets.
- Author
-
Markert, Kel N., Pulla, Sarva T., Lee, Hyongki, Markert, Amanda M., Anderson, Eric R., Okeowo, Modurodoluwa A., and Limaye, Ashutosh S.
- Subjects
- *
WEB-based user interfaces , *STANDARD deviations , *ALTIMETRY , *WATER levels , *WATER supply , *SUSTAINABLE development - Abstract
Understanding the spatial and temporal distribution of hydrologic variables, such as streamflow, is important for sustainable development, especially with global population growth and climate variations. Typical monitoring of streamflow is conducted using in situ gauging stations; however, stations are costly to setup and maintain, leading to data gaps in regions that cannot afford gauges. Satellite data, including altimetry data, are used to supplement in situ observations and in some cases supply information where they are lacking. This study introduces an open-source web application to access and explore altimetry datasets for use in water level monitoring, named the Altimetry Explorer (AltEx). This web application, along with its relevant REST API, facilitates access to altimetry data for analysis, visualization, and impact. The data provided through AltEx is validated using thirteen gauges in the Amazon Basin from 2008 to 2018 with an average Nash-Sutcliffe Coefficient and root mean square error of 0.78 and 1.2 m, respectively. Access to global water level data should be particularly helpful for water resource practitioners and researchers seeking to understand the long-term trends and dynamics of global water level and availability. This work provides an initial framework for a more robust and comprehensive platform to access future altimetry datasets and support research related to global water resources. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
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