A comparison study of raindrop size distribution among five sites at the urban scale during the East Asian rainy season

To study difference at the urban scale (a few tens of kilometers), the raindrop size distribution (DSD) characteristics at five sites (Luhe (LH), Pukou (PK), Jingning (JN), Lishui (LS) and Gaochun (GC)) within five districts of Nanjing are compared using five years of PARticle SIze VELocity (PARSIVEL) disdrometer data during the East Asian rainy season. The percentage of class C5 (extreme rainfall) to rain amount at LH (industrial zone) is significantly higher than that at the other sites (up to 38%). In addition, LH has the largest log(10)N(w) value, while JN (closest to the city center) has the largest D-m value for all rain rate classes and rainfall types. Compared with those of stratiform rainfall, the A and b values of convective rainfall from the Z-R relationship are remarkably more dispersed among the different sites. Moreover, the X-band is more robust to site differences than the S-band and C-band, and thus may be more suitable for rainfall monitoring at the urban scale.