Online Drought Indicators and Indices

Water Requirement Satisfaction Index (WRSI) and Geo WRSI 

 

Index name: Water Requirement Satisfaction Index (WRSI) and Geo-spatial WRSI.

Ease of use: Green.

Origins: Developed by the Food and Agriculture Organization of the United Nations to monitor and investigate crop production in famine-prone parts of the world. Additional work was done by the Famine Early Warning Systems Network.

Characteristics: Used to monitor crop performance during the growing season and based upon how much water is available for the crop. It is a ratio of actual to potential evapotranspiration. These ratios are crop specific, and are based upon crop development and known relationships between yields and drought stress.

Input parameters: Crop development models, crop coefficients and satellite data.

Applications: Used to monitor crop development progress and stress related to agriculture.

Strengths: High resolution and good spatial coverage over all terrains.

Weaknesses: Stress related to factors other than available water can affect the results. Satellite-based rainfall estimates have a degree of error that will affect the results of the crop models used and the balance of evapotranspiration.

Resources: Climate Hazard Group webpage on GeoWRSI and University of Columbia webpage on WRSI.

Reference: Verdin, J. and R. Klaver, 2002: Grid‐cell‐based Crop Water Accounting for the Famine Early Warning System. Hydrological Processes, 16(8): 1617–1630. DOI: 10.1002/hyp.1025. (For more information on this paper, please contact the IDMP HelpDesk).

4 Comments
  1. Tagesse
    February 6, 2017 Reply

    i don’t have good understanding wrsi and geo wrsi?

    1. Robert Stefanski
      February 6, 2017 Reply

      Dear Tagesse,

      The WRSI was developed by FAO and is the basic index and can use weather station data as input. The Geo-Spatial WRSI is based on satellite data as part of the inputs. Here is the description from the GEO-WRSI website at http://chg.geog.ucsb.edu/tools/geowrsi/index.html.

      “The GeoWRSI is a geo-spatial, stand-alone implementation of the Water Requirements Satisfaction Index (GeoWRSI), as it is implemented by the USGS for the FEWSNET Activity. The program runs a crop-specific water balance model for a selected region in the world, using raster data inputs. The program produces a range of outputs which can either be used qualitatively to help assess and monitor crop conditions during the crop growing season, or can be regressed with yields to produce yield estimation models and yield estimates. Other tools are available to post-process the GeoWRSI outputs so that they can be used in yield estimation models. ”

      I hope this answers your question.

      Bob Stefanski
      WMO/IDMP

  2. Tagesse
    July 3, 2017 Reply

    i want to understand of d/t between wrsi their uses

    1. Robert Stefanski
      July 13, 2017 Reply

      Please be more specific in your request. Is is unclear what d/t is?

      Robert
      IDMP

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