Rainfall Anomaly Index (RAI)

Rainfall Anomaly Index (RAI)

 

Index name: Rainfall Anomaly Index (RAI).

Ease of use: Yellow.

Origins: Work began in the early 1960s by van Rooy.

Characteristics: Uses normalized precipitation values based upon the station history of a particular location. Comparison to the current period puts the output into a historical perspective.

Input parameters: Precipitation.

Applications: Addresses droughts that affect agriculture, water resources and other sectors, as RAI is flexible in that it can be analysed at various timescales.

Strengths: Easy to calculate, with a single input (precipitation) that can be analysed on monthly, seasonal and annual timescales.

Weaknesses: Requires a serially complete dataset with estimates of missing values. Variations within the year need to be small compared to temporal variations.

References:
Kraus, E.B., 1977: Subtropical droughts and cross-equatorial energy transports. Monthly Weather Review, 105(8): 1009-1018. DOI: 10.1175/1520-0493(1977)105<1009:SDACEE>2.0.CO;2.

van Rooy, M.P., 1965: A Rainfall Anomaly Index independent of time and space. Notos, 14: 43–48.

14 Responses

    1. Dear Sewinj
      RAI can be calculated using precipitation data on monthly, seasonal and annual timescales.
      Best regards
      IDMP TSU

    1. Dear Anudeep,

      Please be more specific in your request? I am assuming that you talking about the RAI?

      IDMP team

    1. Dear Munmun Rahman,

      We only have the two references of the RAI:
      Kraus, E.B., 1977: Subtropical droughts and cross-equatorial energy transports. Monthly Weather Review, 105(8): 1009-1018. DOI: 10.1175/1520-0493(1977)105<1009:SDACEE>2.0.CO;2.

      Yon can download the first one here:
      https://journals.ametsoc.org/doi/pdf/10.1175/1520-0493%281977%29105%3C1009%3ASDACEE%3E2.0.CO%3B2

      van Rooy, M.P., 1965: A Rainfall Anomaly Index independent of time and space. Notos, 14: 43–48.

      IDMP Team

  1. Unfortunately, I am not aware of any software to calculate this index. Have you looked at the two references (Kraus, 1977 and van Rooy, 1965)??

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