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United States Department of Agriculture

Agricultural Research Service

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Location: Hydrology and Remote Sensing Laboratory

2012 Annual Report

1a. Objectives (from AD-416):
To bring an existing drought and ET remote sensing model (ALEXI) into operational function within NOAA-NESDIS, and to deliver products to NAA-CPC, the National Drought Mitigation Center (NDMC), and the NIDIS Drought Portal for use in operational drought monitoring within the U.S. and North America.

1b. Approach (from AD-416):
The ALEXI model automated infrastructure will be connected to standard NOAA input products and conformed to run on a computing platform at NESDIS. An archive of model output will be generated for 2000-present over the contiguous U.S., and for 2007-present for a domain covering North America. Monthly anomalies in an Evaporative Stress Index (ESI), ET and soil moisture from the model will be compared with standard drought indices, with soil moisture observations, and with known drought events to ascertain robustness and model sensitivity. After ESI has been evaluated, it will be used to verify drought forecasts generated by CPC for the North American Drought Briefing. ALEXI drought products will be delivered in real-time to CPC and to NDMC for operational monitoring, and they will also be distributed through the U.S. Drought Portal.

3. Progress Report:
In Year 1 of this project, the primary implementation tasks were to 1) port the Atmospheric-Land Exchange Inverse (ALEXI) processing infrastructure, currently running at University of Alabama-Huntsville (ALEXI-UAH), to machines at National Environmental Satellite Data and Information Service (NESDIS), integrating standard NOAA input products (ALEXI-NOAA); and 2) conduct an intercomparison of the existing 10-year ALEXI-UAH Evaporate Stress Index (ESI) archive with standard drought indices used in the U.S. Drought Monitor (USDM) and North American Drought Briefing (NADB), and with the USDM itself. For task 1: Hourly skin temperature and insolation for much of the archive period have been obtained from the NESDIS GOES Surface and Insolation Product (GSIP) and collocated to the North American ALEXI domain. Meteorological inputs to ALEXI are being extracted from the Regional Climate Data Assimilation System (R-CDAS) – the real-time continuation of the North American Regional Reanalysis (NARR) performed by the National Center for Environmental Prediction (NCEP) Environmental Modeling Center (EMC). For task 2: An intercomparison was conducted between the Evaporative Stress Index (ESI), standard precipitation-based indices and drought classifications reported in the USDM during 2000-2009. Spatial distributions in ESI were found to correlate well with patterns in the precipitation-based indices, responding to rainfall events at monthly timesteps. In Year 2 of this project, the primary implementation tasks completed were to 1) complete porting of the ALEXI continental U.S. (CONUS) processing infrastructure to machines at NESDIS, integrating standard NOAA input products; 2) develop infrastructure to run a second ALEXI domain over North America (NA); 3) continue evaluation of the CONUS drought product; and 4) develop a web interface for data distribution and visualization, to be linked to the Drought Portal. A website was developed at HRSL to visualize ESI products side-by-side in comparison with USDM drought classifications, both in real-time and retrospectively.

4. Accomplishments

Last Modified: 06/27/2017
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