This paper introduces and evaluates DryMOD. a dynamic water balance model of the key hydrological process in drylands that is based on free. public-domain datasets. The rainfall model of DryMOD makes optimal use of spatially disaggregated Tropical Rainfall Measuring Mission (TRMM) datasets to simulate hourly rainfall intensities at a spatial resolution of 1-km. https://www.remtavares.com/