This is the new (GPM-formated) TRMM product. It replaces the old TRMM_3A25,3A26
Version 07 is the current version of the data set. Older versions will no longer be available and have been superseded by Version 07.
This is the GPM-like formatted TRMM Precipitation Radar (PR) monthly gridded data, first released with the "V8" TRMM reprocessing. The TRMM radar Level 3 grids are now consistent with the GPM Dual-frequency Precipitation Radar (DPR). The closest ancestor of this dataset was the monthly radar statistics 3A25.
This product consists of monthly statistics of the PR measurements at 0.25x0.25 degrees, and monthly histograms and statistics at 5x5 degrees, horizontal resolution.
The objective of the algorithm is to calculate various daily statistics from the level 2 PR
output products. Four types of statistics are calculated:
1. Probabilities of occurrence (count values)
2. Means and standard deviations
3. Histograms
4. Correlation coefficients
In all cases, the statistics are conditioned on the presence of rain or some other quantity such
as the presence of stratiform rain or the presence of a bright-band. For example, to compute
the unconditioned mean rain rate, the conditional mean must be multiplied by the probability
of rain which, in turn is calculated from the ratio of rain counts to the total number of
observations in the box of interest.
The grids are in the Planetary Grid 2 structure matching the Dual-frequency PR on the core GPM observatory that covers 67S to 67N degrees of latitudes. The low resolution 5x5 deg grid covers 70S to 70N. Areas beyond the ±40 degrees of latitudes are padded with empty grid cells.