THE RELATION BETWEEN PREVAILING PRECIPITATION-PARTICLE TYPE AND RADARECHO STRUCTURE AROUND THE DEWA HILLS

Snow clouds influenced by topography were observed on 13-19 February 1 992, and were analyzed using the data of Doppler radars, surface obser vations and rawinsondes. The analysis period was divided into two stag es (stages I and II) based on the radar echo pattern and the rawinsond e data. The radar echo intensified over the Dewa Hills in both stages. Each stage represented the different type of snow cloud. The cloud ty pe was clearly related to the prevailing precipitation-particle type. The cold outbreak was weak and widespread echoes appeared in stage I. Snowflakes were dominated among the observed precipitation-particles, and weak orographic lifting was expected, It is suggested that deposit ion growth prevailed over the Dewa Hills in stage I. The cold outbreak was strong and many echo cells were observed in stage II. Graupels do minated among the observed precipitation-particles. The low-level wind favored the strong orographic lifting. It is inferred that riming gro wth prevailed over the Dewa Hills in stage II. The contribution of gra upel to the precipitation intensity was larger when the observation si te was closer to the center of an echo cell. (C) 1998 Elsevier Science B.V. All rights reserved.