Online Drought Indicators and Indices

Vegetation Health Index (VHI)


Index name: Vegetation Health Index (VHI).

Ease of use: Green.

Origins: The result of work done by Kogan with NOAA in the United States.

Characteristics: One of the first attempts to monitor and identify drought-related agricultural impacts using remotely sensed data. AVHRR data in the visible, infrared and near-infrared channels are all used to identify and classify stress to vegetation due to drought.

Input parameters: AVHRR satellite data.

Applications: Used to identify and monitor droughts affecting agriculture around the world.

Strengths: Coverage over the entire globe at a high resolution.

Weaknesses: The period of record for satellite data is short.

Resources: The calculations and sample case studies are given in the literature. VHI maps can be found online at NOAA STAR – Global Vegetation Health Products webpage.

Kogan, F.N., 1990: Remote sensing of weather impacts on vegetation in non-homogeneous areas. International Journal of Remote Sensing, 11: 1405–1419. DOI: 10.1080/01431169008955102. (For more information on this paper, please contact the IDMP HelpDesk).

Kogan, F.N., 1997: Global drought watch from space. Bulletin of the American Meteorological Society, 78: 621–636. DOI: 10.1175/1520-0477(1997)078<0621:GDWFS>2.0.CO;2.

Kogan, F.N., 2001: Operational space technology for global vegetation assessments. Bulletin of the American Meteorological Society, 82(9): 1949–1964. DOI: 10.1175/1520-0477(2001)082<1949:OSTFGV>2.3.CO;2.

Currently used by: Iran.

  1. Neema
    September 3, 2020 Reply

    Are there any studies that used the vegetation health index to assess or predict crop yield and pasture availability?

    Thank you.

    1. Robert Stefanski
      September 7, 2020 Reply

      Dear Neema,

      Thank you for your question. We are only aware of the references listed on the VHI page:

      However, we encourage you to do a Google search and share any results in this forum.

      Best regards,
      IDMP TSU

  2. Lee vv
    January 31, 2020 Reply

    I see snow and ice and missing values annotated on the map, and the cloud was not mentioned. Does the calculation of VHI including cloud?

    1. Katrin Ehlert
      February 3, 2020 Reply

      Dear Lee vv

      Vegetation health products are calculated from data collected during cloud-free conditions. Cloud information is collected during data collection to identify the quality of the observation. An example of such a product is the VIIRS cloud mask intermediate product (IICMO) from NASA.

      Best regards
      IDMP team

  3. Brian Kimathi
    April 15, 2019 Reply

    Does an API for a system like this exist?

    1. Katrin Ehlert
      April 30, 2019 Reply

      Dear Brian Kimathi

      Thank you for your question. Here is a link to the NOAA STAR web page that has vegetation health indices:

      Kind regards
      IDMP Team

  4. […] following time-series animation shows Vegetation Health Index (VHI) maps  of the Philippines from February 2000–May 2017. This was computed using two indices that […]

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