Gridded rainfall depth-duration-frequency (DDF) estimates for the state of Kerala, India, 1979-2020

1, 6, 24 and 192-hour annual maximum rainfalls were extracted from the gridded Indian Monsoon Data Assimilation and Analysis (IMDAA) hourly rainfall dataset for each year of 1979-2020 inclusive, for each grid cell in the state of Kerala, India. At each point, the median, and L-moments of the 42 annual maxima were calculated separately for each duration. At each location, linear regressions were created for the median using longitude, latitude, duration and mean annual rainfall. Linear regressions were created for the first two L-moments using these descriptors variables plus altitude and modelled median of annual maxima. The generalized logistic distribution was then used with the modelled median and L-moment ratios at each site to estimate the rainfall depths associated with specified durations and return periods.