Drought Drought Everywhere, And Not a Model to Use: Monitoring Drought in Uruguay

Team Location: International Research Institute for Climate and Society, Palisades, New York

The DSI (using NDDI for the VI) applied over Uruguay for January 2013. Darker tones indicate areas impacted by drought to a greater degree. Image Credit: Uruguay Agriculture Team, NASA DEVELOP National Program

The DSI (using NDDI for the VI) applied over Uruguay for January 2013. Darker tones indicate areas impacted by drought to a greater degree. Image Credit: Uruguay Agriculture Team, NASA DEVELOP National Program



Authors:
Jerrod Lessel (California State University, Fresno)

Mentors/Advisers:
Pietro Ceccato, Ph.D. (Lead Environmental Monitoring Program, International Research Institute for Climate and Society, The Earth Institute, Columbia University)

Past/Other Contributors:
Kenton Ross, Ph.D. (NASA, DEVELOP National Science Adviser)
DEVELOP 2013 Summer Great Plains Agriculture, Langley Research Center (Lance Watkins, Jerrod Lessel, Alexandra Perillo)

Abstract:
The U.S. uses a statewide decision support tool called the U.S. Drought Monitor to observe drought conditions on a weekly basis. This tool in turn helps ranchers, farmers and policymakers make key decisions about how drought is affecting their area of concern on a regional scale. While the country of Uruguay does have some tools to assist its people — such as Normalized Difference Vegetation Index (NDVI) and water balance monitoring — it may be useful to have a tool similar to the U.S. Drought Monitor. A Drought Severity Index (DSI) could be created for local-scale drought monitoring based on methods from Rhee et al. (2010) which combine Land Surface Temperature (LST), a Vegetation Index (VI) and Precipitation. Rhee et al. (2010) showed that the Normalized Difference Drought Index (NDDI) was the superior VI for humid climates based on their comparison of four VI’s. This version of the DSI, which includes the NDDI parameter, may be more applicable to Uruguay given its humid/semi-humid climate. The NDDI is defined as: (NDVI-NDWI)/(NDVI+NDWI) where NDVI is the Normalized Difference Vegetation Index and NDWI is the Normalized Difference Water Index. These parameters can be easily obtained using NASA’s Earth Observing System (EOS) and can be transformed into a drought monitor for the country of Uruguay using the International Research Institute for Climate and Society (IRI) Data Library and ArcGIS. This study analyzed the effectiveness of the NDDI parameter for the country of Uruguay and compared its drought sensitivity to that of other VI’s such as NDVI and NDWI. With the proper VI chosen, the methodology is used in the International Research Institute for Climate and Society’s (IRI) data library. The new methodology was tested and the new DSI was transferred to project partners, the Instituto Nacional de Investigación Agropecuaria (INIA) and Uruguay’s Ministry of Agriculture. This tool will be useful to the land managers and policymakers as a decision-support tool for drought mitigation and preparedness.



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