Online Drought Indicators and Indices

Percent of Normal Precipitation

 

Index name: Percent of Normal Precipitation.

Ease of use: Green.

Origins: The percentage of any quantity is a simple statistical formulation. The exact origin or first use is not known in describing precipitation anomalies.

Characteristics: Simple calculation that can be used to compare any time period for any location. Can be computed on daily, weekly, monthly, seasonal and annual timescales, which will suit many users needs. Calculated by dividing actual precipitation by normal precipitation for the time being considered and multiplying by 100.

Input parameters: Precipitation values suitable for the timescale being calculated. It is ideal to have at least 30 years’ worth of data for calculation of the normal period.

Applications: Can be used for identifying and various impacts of droughts.

Strengths: A popular method that is quick and easy to calculate with basic mathematics.

Weaknesses: Establishing the normal for an area is a calculation that some users could confuse with mean or average precipitation. It is hard to compare different climate regimes with each other, especially those with defined wet and dry seasons.

Reference: Hayes, M.J., 2006: Drought Indices. Van Nostrand’s Scientific Encyclopedia John Wiley & Sons, Inc., doi: 10.1002/0471743984.vse8593.

5 Comments
  1. adham jalab
    March 13, 2017 Reply

    hallo, I am Dr jalab from syria , tishreen uni , I need this information ( percent of normal precipitation)
    and thankyou for yor help
    Dr. jalab

    1. Robert Stefanski
      March 13, 2017 Reply

      Dr Jalab, Please be more specific with your request. What exactly do you need?

  2. Mr. Sok Kimhuy
    May 20, 2017 Reply

    Dear Dr. Robert Stefanski,

    I would like to know about the calculation procedure of Percentage of Normal Precipitation. Since, I want to use this index to analyze the drought severity in Cambodia.

    Sincerely your,

    Kimhuy

    1. Robert Stefanski
      July 13, 2017 Reply

      Percent of Normal Precipitation is a simple calculation that can be used to compare any time period for any location. Can be computed on daily, weekly, monthly, seasonal and annual timescales, which will suit many users needs. Calculated by dividing actual precipitation by normal precipitation for the time being considered and multiplying by 100.
      Thanks.

  3. akash
    June 14, 2017 Reply

    I want pni drought index data

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