TRMM/PR L3 Monthly Surface Rain is obtained from the PR sensor onboard TRMM and produced by the Japan Aerospace Exploration Agency (JAXA). The Precipitation Radar (PR) is the primary instrument onboard TRMM. The most innovative of the five TRMM instruments, the PR is the first quantitative rain radar instrument to be flown in space. The major objectives of the PR instrument are as follows:a. Provides a 3-dimensional rainfall structureb. Achieves quantitative measurements of the rain rates over both land and ocean When properly combined with TMI measurements, the Precipitation Radar (PR) data is instrumental in obtaining the height profile of the precipitation content, from which the profile of latent heat release from the Earth can be estimated. The rain rate is estimated from the radar reflectivity factor when the rain rate is small by applying conventional algorithms used for ground-based radar. For large rain rates, a rain attenuation correction is made using the total-path attenuation of land or sea surface echoes. Monthly rainfall, rain rate averages, rain rate standard deviation and probability distribution function in 5deg x 5deg grid at three layers in the height of 2 km, 4 km and 6 km.The provided format is HDF4. The statistical period is 1 month. The current version of the product is Version 7. The generation unit is global.