SERVIR, a joint initiative of the National Aeronautics and Space Administration (NASA) and United States Agency for International Development (USAID), has released a new global geospatial dataset for agriculture and food security around the world. The dataset, called the Evaporative Stress Index (ESI), is available for analysis and download, and produced weekly at 5-km resolution for the entire globe.
The ESI has been developed by Christopher Hain of NASA’s Marshall Space Flight Center in Huntsville, Alabama. Increasing uncertainties in weather patterns in recent times and availability of water for irrigation pose a serious challenge to crop production, threatening global food security.
What the dataset offers?
The global geospatial dataset for agriculture reveals the regions of drought where vegetation is stressed due to lack of water. The index captures early signals of “flash drought,” a condition brought about by rapid rise in temperature, leading to drying up of the air, reduced rainfall and moisture evaporating quickly from the soil. It is prudent to monitor the rate of water loss through the use of land surface temperature before and take required remedial measures before the condition actually starts having an effect on the vegetation.
SERVIR’s ESI is capable of giving soil moisture data without using observed rainfall data, which is critical in developing countries of the world that lack sufficient ground-based observations of rainfall. The index is based on satellite observations of land surface temperature, which are used to estimate water loss due to evapotranspiration — the loss of water via evaporation from soil and plant surfaces and via transpiration through plant leaves. Variations in land surface temperature enables the ESI to calculate how the current rate of evapotranspiration compares to normal conditions.
According to SERVIR, the ESI can be used to:
- Reveal where vegetation is stressed due to lack of water, enabling more accurate drought monitoring and/or forecasts
- Observe rapidly developing “flash droughts” as developing vegetation stress is evident in the LST signal used in ESI before it is shows a signal in vegetation-based indices (eg, NDVI, EVI)
- Provide farmers with actionable information to make more information decisions during periods of drought (eg, irrigation scheduling)
- Assist local governments and the agricultural sector in implementing short and long-term mitigation measures during and in advance of droughts.
ESI data is usually composited over a given period of time to provide full spatial coverage and to reduce noise in the daily retrievals. SERVIR’s global ESI is composited over a 4-week and 12-week periods. The 4-week ESI composite has a shorter time scale response and may be more representative of fast changing conditions, while the 12-week ESI composite has a slower response, as it integrates data over a longer period of time, and may be more representative of slow changing conditions.
To analyze Evaporative Stress Index (ESI) data, a user simply has to go to http://ClimateSERV.servirglobal.net, choose Get Started, draw a polygon or choose a feature on the map, and then select the ESI as data source.
To download ESI) data as tif files, go to https://gis1.servirglobal.net/data/esi/
To visualize ESI data in a WMS, see ArcGIS REST Service: https://gis1.servirglobal.net/arcgis/rest/services/Global/ESI_4WK/MapServer
Who all are using it?
A geospatial dataset for agriculture has been available over the United States for several years now, but NASA’s Applied Sciences Water Resources recently funded the program for development of the global ESI dataset. The US Department of Agriculture Foreign Agricultural Service is planning to integrate the global ESI dataset this year in a test mode.
Scientists for the Group on Earth Observations Global Agricultural Monitoring (GEOGLAM) Crop Monitor for the Agricultural Market Information System (AMIS) have been experimenting with the global ESI product for over a year in support of agricultural ministries around the world. The Crop Monitor reports provide monthly maps and summaries of crop conditions — by crop type — within the main agricultural regions of the AMIS countries (G20+7). GEOGLAM has already integrated the global ESI product into its monthly evaluations of crop conditions for our crop monitor bulletins. Further, the International Center for Biosaline Agriculture’s Middle East and North Africa (MENA) Regional Drought Management System is using the global ESI as an input to a regional Composite Drought Index over the MENA region.
What is SERVIR and what does it do?
SERVIR works in over 45 countries acoss the world in partnership with leading regional organizations to help developing regions of the use satellite data and other geospatial technologies for managing climate risks and land use. It aims to empower decision-makers with tools, products, and services to act on issues such as natural disasters, Climate Change, agriculture, water, and ecosystems and land use. It has so far collaborated with over 250 institutions, trained more than 3,000 individuals, and developed over 70 custom tools to improve the capacity of those countries to develop local solutions.
Its diverse collection of user-tailored applications and tools use EO data, primarily from NASA, to inform resilient development in various regions in a number of thematic areas such as forest fire monitoring system, agriculture monitoring, frost monitoring and forecasting in Africa. Some of SERVIR’s other popular applications are:
- Agricultural Monitoring to Support Food Security in the Eastern Himalaya
- Climate Change Vulnerability and Adaptation Strategies of Forest Ecosystems
- CREST Streamflow Viewer – Eastern Africa and Bhutan
- Flood Simulator for African Basins
- Forest Cover Monitoring of Hot Spots Using Landsat 8 Data
- Forest Fire Detection and Monitoring System.
One can use the search filter to check out regions and themes one is interested in.
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