To Catch a Cloud - Multiscale Precipitation Processes in the Andes and in the Himalayas

A synthesis from ground- and satellite-based observations and modeling studies in the Central Himalayas and in the Central Andes toward characterizing the altitudinal organization of precipitation regimes in High-Mountains is presented focusing on local and remote controls of the seasonality of moisture transport, terrain topology (connectivity, gradients and barriers) and vegetation controls on the diurnal cycle cloudiness and precipitation, and cloud-rainfall interaction controls of precipitation intensity and duration. Detailed observations and modeling studies of selected events during the monsoon and in the transition seasons will be anaflyzed as follows: 1) the inter-annual variability of monsoon onset and winter storms with implications for the spatial dynamics of flooding and drought in the Himalayas, 2) cloud runup at the treeline with implications for the altitudinal capping of rainfall in the Andes, and 3) extreme precipitation from "super-cloudbursts" with implications for flashfloods and landslides in the Himalayas and in the Andes. A matrix of observational and modeling needs with traceability to key science questions is suggested.