Cloud vertical structures associated with precipitation magnitudes over the Tibetan Plateau and its neighboring regions

Abstract

Cloud vertical structures and precipitation over the Tibetan Plateau (TP) are analyzed and compared with its neighboring land and tropical oceans based on CloudSat/CALIPSO satellite measurements and TRMM precipitation data. Results show that the TP generally has a compression effect on cloud systems, as manifested by a shrinking cloud depth and lowering cloud top. Precipitation is weaker over the TP than its neighboring regions and exhibits large seasonal variations. In summer, cloud ice particles over the TP are mostly located at lower altitude (5–10 km), with a larger variability of sizes and aggregation (particle number concentration) under no-rain conditions compared to other regions. Ice water content becomes abundant and the number concentration tends to be dense at higher altitudes when precipitation is enhanced. However, even for heavy rainstorms, the aggregation is most likely between 100 and 250 L⁻¹, whereas it can reach as high as 500 L⁻¹ over its neighboring land and tropical oceans. Given the same magnitude of precipitation, the spectrum of ice particle sizes is found to be wider over the TP than other regions.