Comparison between empirical lognormal and gamma rain drop-size distribution models for Indian region

The disdrometer data on rain drop sizes, collected at Ahmedabad (India), has been analyzed to develop empirical model on drop-size distribution (DSD). Analyses has been carried out to find suitability of lognormal or gamma distribution. The lognormal distribution has been found to give better correlation. The data has been analysed on annual and monthly basis to find out seasonal variability. Statistical analysis on rate of rain fall was carried out on monthly and annual basis to derive rain rate exceedance characteristic. August appears to be worst month from the attenuation point of view.