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).

  1. Mamadou
    July 8, 2021 Reply

    Hello GeoWRSI team
    I am Mamadou SARRA, student in master’s degree in climate change and sustainable development at the AGRHYMET regional center. I am currently working on my thesis topic entitled “Impact of climate change on water availability for lowland crops in Mali”. As part of this work I would like to use the GeoWRSI application to know the indices of satisfaction of rice water needs with the data of climate change from the CNRM and IPSL models according to the Rcp45 and 85 scenarios. the WRSI following three periods that:
    – the period from 1986 to 2005 or the past
    -from 2021 to 2041, the period of the horizon 2030
    -from 2042 to 2062, for the 2050 horizon
    My concern is that I never use this app and there isn’t a lot of tutorial available on the net. at the first installation the software displays an error message. I do not know what to do. Help me integrate my data to calculate WRSI.
    Thank you

    1. Katrin Ehlert
      July 12, 2021 Reply

      Dear Mamadou SARRA
      Thank you for your comment. We have contacted the GeoWRSI team and received the following response:
      We would like to advise that the GeoWRSI is not well suited to this research question. It is really designed for agricultural drought monitoring applications for crops like maize and sorghum and I would not be confident in its ability to represent rice well. Also, we have no compatible climate change simulations for driving the model. Sorry to not be more helpful, but this kind of research is not really well suited to what the CHC is capable of supporting … perhaps CCAFS or AgMIP might be more useful sources of modeling frameworks.
      Best regards
      IDMP TSU

      1. Mamadou
        July 12, 2021 Reply

        Hello Katrin Ehlert
        Message well received. However I will need to understand how to prepare the input files in the model and regarding the error message that the model displays on startup. Which solution?

  2. Aziz
    August 7, 2020 Reply

    I have already used the Geo WRSI software during my PhD as in this paper However, I installed the v3.8.011 now but once I run the program, I’m getting this message “There was an error reading the user settings. GeoWRSI will now proceed to reset all program settings”.
    Thank you in advance for your help to fix it

  3. Oshneck Mupepi
    July 2, 2020 Reply

    when calculating WRSI , do we ave to extract cropland only or it applies to the whole area including non-crop lands then we generalise .

    1. Katrin Ehlert
      July 10, 2020 Reply

      Dear Oshneck Mupepi

      Thank you for your comment. The WRSI is calculated using satellite data (PET and rainfall) and soil information (e.g. FAO soil maps). The resolution of these data sets may not allow for cropland distinction. You can find an example for map resolution here:

      On the calculation of the WRSI and necessary data, you may find the following document helpful:

      Best regards
      IDMP team

  4. Coonie
    January 22, 2020 Reply

    Please may you help with the WRSI ranges for a season. eg 0-10 means bad season, 20-40 fair something like this. Its so hard for me to foind it i have tried so hard but to no avail. Regards

    1. Katrin Ehlert
      February 3, 2020 Reply

      Dear Coonie
      The Water Requirement Satisfaction Index is an indicator for the soil water availability to a given crop. It is a ratio of actual to potential evapotranspiration. The following categories for the WRSI can be found on the WRSI webpage of the University of Columbia (
      WRSI = 100% (“sufficient”)
      WRSI = 60-99% (“satisfactory”)
      WRSI = 10-60% (“stress”)
      WRSI = 0-10% (“wilting”)

      Best regards
      IDMP team

  5. Issa Camara
    January 20, 2020 Reply

    Cher Katrin,
    Je vous remercie pour votre réaction. Certes j’ai vu une bonne description du logiciel et un document permettant son utilisation. Toutes fois je n’arrive pas à retrouver la partie ou le fichier qui présente les algorithmes ou les formules utilisés dans la conception du logiciel.
    Puis je donc avoir le fichier décrivant ces algorithmes ou formules implémenté dans le logiciel.
    Merci de votre bonne collaboration.


    1. Katrin Ehlert
      January 21, 2020 Reply

      Bonjour Issa Camara

      Au but d’obtenir plus d’information sur les algorithmes du logiciel Geo WRSI, nous vous recommendons de contacter Tamuka Magadzire (développeur de Geo WRSI) ou bien un autre membre du Climate Hazards Center de UCSB (

      Le WRSI a été originalement developpé par FAO, veuillez aussi consulter la page web suivante et les liens mentionnés sur ce site:

      L’équipe IDMP

  6. Issa Camara
    January 13, 2020 Reply

    Bonjour chère équipe Géo WRSI,

    Je suis doctorant en geoscienes et environnement en Côte d’Ivoire.
    Je souhaite utilisé votre logiciel dans le cadre de ma thèse. Je voulais donc que vous me donner si possible la fiche technique (les algorithmes ou formules) qui ont été utilisé pour l’élaboration du logiciel. Cela me serai d’une aide immense dans la rédaction de mon document.

    1. Katrin Ehlert
      January 16, 2020 Reply

      Bonjour Issa Camara

      Merci de votre demande. Nous présontons sur notre site web le Geo WRSI, cépendant pour recevoir des informations techniques sur ce logiciel nous vous redirigons à la page web du Climate Hazards Center of UCSB (
      Veuillez aussi trouver le commentaire de Tamuka Magadzire (développeur de Geo WRSI) au dessus.

      l’equipe IDMP

  7. Sophie
    October 15, 2019 Reply

    Dear Geo WRSI team,

    I have got two questions about the period of the data imported into the Geo WRSI model,

    1. For crop performance during the growing season, does Geo WRSI have projection data?
    For example, we are October 15. 2019 now, do you have forecast data until December 15. 2019?

    2. Is it possible to import (seasonal) forecast data into the Geo WRSI model?
    That would make sense if I want to guess the crop yield of next year in March 15, 2020, for example.

    Thank you.

    I look forward to hearing you back.

    Best regards,

    1. Katrin Ehlert
      November 12, 2019 Reply

      Dear Sophie

      Thank you for your message.
      The Geo WRSI index is is an indicator of crop performance based on the availability of water to the crop during a growing season. Season end can be calculated in a forecast estimate (“Extended WRSI”) using long-term average climatological data.
      As for forecasts, the Geo WRSI program produces a range of outputs which can either be used qualitatively to assess and monitor crop conditions during the 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.

      For more information, please refer to the Geo WRSI websites indicated in the Geo WRSI post on our website or direct your questions to the Climate Hazard Center of UCSB

      Best regards,
      IDMP Team

    June 3, 2019 Reply

    hi i’m trying to install correctly the GEOWRSI V3.8001 but I can’t. it is rigthing that there was an error reading the user setting. does anyone can help me please

    1. Katrin Ehlert
      June 3, 2019 Reply

      Dear Zananirina

      Thank you for your message. For technical help on the GeoWRSI software, please direct yourself to the developers via the corresponding website:

      You might also find Tamuka Magadzire’s comment (above) interesting.

      Kind regards,
      IDMP Team

  9. Shankar Meti
    March 30, 2019 Reply

    I wan to do GeoWRIS analysis for Indian region but this is not available in software. Where we will get the all the input data set for Asia region.

    1. Katrin Ehlert
      April 30, 2019 Reply

      Dear Shankar Meti
      Thank you for your comment. Please take a look at the following link:
      This website should have data for around the world. Also take a look at the CHIRPS data set.
      Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS) is a 30+ year quasi-global rainfall dataset. Spanning 50°S-50°N (and all longitudes), starting in 1981 to near-present, CHIRPS incorporates 0.05° resolution satellite imagery with in-situ station data to create gridded rainfall time series for trend analysis and seasonal drought monitoring.

      As noted above, the CHIRPS data set should have data for India, but please explore the CHIRPS data set and let us know what you can find.

      Kind regards
      IDMP Team

    2. Tamuka Magadzire
      May 23, 2019 Reply

      Dear Sankar,

      As noted by Katrin, Climate Hazards Center and FEWS NET does have rainfall data for much of the world. The other datasets that you will need include soil water holding capacity (WHC), length of growing period (LGP), and potential or reference evapotranspiration (PET) data. While PET is global, the other two are only available from us for specific regions (the regions covered by GeoWRSI), but there are methods you can use to derive the other LGP and PET for other regions.

      I am one of the developers of the GeoWRSI software, and will be happy to answer any other questions you may have regarding GeoWRSI.


  10. 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?


  11. 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

      “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

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