Source: Derived from the Tropical Rainfall Measuring Mission (TRMM) data
Formula: (TRMijk - TRMi,min)/(TRMi,max + TRMi,min)
TRMMijk—monthly TRMM for pixel i, in month j, for year k
TRMMi,min—multi-year minimum TRMM for pixel i
TRMMi,max—multi-year maximum TRMM
