International Precipitation Working Group

The International Precipitation Working Group (IPWG) was established as a permanent Working Group of the Coordination Group for Meteorological Satellites (CGMS) on 20-22 June 2001 in Ft. Collins, CO. The IPWG is co-sponsored by CGMS and the World Meteorological Organization (WMO) and focuses the scientific community on operational and research satellite based quantitative precipitation measurement issues and challenges.
It provides a forum for operational and research users of satellite precipitation measurements to exchange information on methods for measuring precipitation and the impact of space borne precipitation measurements in numerical weather and hydrometeorological prediction and climate studies.


You may want to take a look at our history as a Group. Please click here.


In the area of quantitative precipitation estimation, the IPWG builds upon the expertise of scientists who are currently involved in precipitation measurements from satellites with emphasis on derivation of products. The IPWG is established to foster the:

  • Development of better measurements, and improvement of their utilization;
  • Improvement of scientific understanding;
  • Development of international partnerships.


The objectives of the IPWG are:

  1. to promote standard operational procedures and common software for deriving precipitation measurements from satellites;
  2. to establish standards for validation and independent verification of precipitation measurements derived from satellite data; including:
    • reference standards for the validation of precipitation for weather, hydrometeorological and climate applications;
    • standard analysis techniques that quantify the uncertainty of ground based measurements over relevant time and space scales needed by satellite products;
  3. to devise and implement regular procedures for the exchange of data on inter-comparisons of operational precipitation measurements from satellites;
  4. to stimulate increased international scientific research and development in this field and to establish routine means of exchanging scientific results and verification results;
  5. to make recommendations to national and international agencies regarding the utilization of current and future satellite instruments on both polar and geostationary platforms; and
  6. to encourage regular education and training activities with the goal of improving global utilization of remote sensing data for precipitation measurements.


The Working Group shall be comprised of representatives nominated by the satellite operators of the CGMS, other members of CGMS and relevant research satellite operators. The CGMS or the IPWG may invite other experts from the community to participate in the activities of the group.
The Group wider body is composed of all scientists, operational hydrometeorologists and stakeholders who are interested in the progress of satellite precipitation estimations for a wide variety of applications. In this respect, there is no limit to membership and all these categories of scholars and professionals are strongly encouraged to apply. The Group needs input from all his members.
The following graphs show the IPWG membership to date divided by countries

and by continents

The membership has been constantly growing since the IPWG foundation. Here is the total number of members over the past few years

and the graph of members by continent


The Working Group will be chaired by two Co-Chairs (incoming) appointed by the plenary of the CGMS. At the same time, the two past Co-Chairs (outgoing) enter a supporting function so that continuity is ensured. The Co-Chairs in charge shall compile a report on relevant activities for the scheduled plenary meetings of the CGMS. The interactive connection with satellite operators will be performed through the use of a Rapporteur who will attend and report to the CGMS meetings.
Under the lead of the two Co-Chairs, the IPWG organizes Workshops, co-sponsored by CGMS and WMO, approximately every two years. The Workshops promote the exchange of scientific and operational information between the producers of precipitation measurements, the research community, and the user community.