Abstract We investigate the relationships among the mass-weighted mean diameter (\: {D}₌), normalized intercept parameter (\: {N}ₖ), and rainfall rate (R) using five disdrometers and GPM Dual-frequency Precipitation Radar (DPR) observations over the northeastern Indian subcontinent. By extending the conventional \: {D}₌ – \: {N}ₖ framework to include rainfall rate, we directly link rainfall microphysics to rainfall intensity. Rainfall with 1. 5 ≤ \: {D}₌ < 2. 5 mm exhibits a bimodal structure in the \: {D}₌ – R – \: {N}ₖ relationship, consisting of Type A rainfall (\: {N}ₖ ≥ 36 dB) with high rainfall rates and Type B rainfall (\: {N}ₖ < 36 dB) with lower rainfall rates. Type A rainfall is more frequent during the monsoon season and over orographic regions. The DPR product shows limited variability in \: {N}ₖ and rarely reproduces high- \: {N}ₖ rainfall, leading to systematic underestimation of rainfall intensity. These results highlight the importance of representing \: {N}ₖ variability for improving satellite-borne precipitation radar retrievals.
Murata et al. (Wed,) studied this question.