Observation of Clouds characteristics over the Eastern Tibetan Plateau

Clouds are closely related to weather and serve as a key factor in Earth’s climate system. Over the Tibetan Plateau (TP), cloud variations significantly impact radiation budgets and the global water cycle. This study examines cloud characteristics at the Large High Altitude Air Shower Observatory (LHAASO) site using CL51 ceilometer data (October 2020-June 2022) and CloudSat-CALIPSO data (2010-2019), analyzing cloud occurrence frequency (COF), cloud vertical structure (CVS), including cloud base height (CBH) and cloud layer stratification, while assessing MERRA- 2 reanalysis data performance. Results show comparable COF between ground-based (43.7%) and satellite measurements (44.9%), with nighttime (October-May, 20:00-05:00 Beijing time) frequency averaging 34.2% and reaching its minimum at midnight. Distinct seasonal patterns emerge, showing maximum CBH in summer and minimum in winter. Single-layer clouds dominate the region, with summer and autumn exhibiting pronounced unimodal vertical structures, while spring and winter display more uniform distributions. MERRA-2 accurately represents high-level clouds but significantly underestimates mid- and low-level clouds. Both observation methods detect frequent cloud occurrence around 1 km, though satellite data reveals an additional peak near 5 km. These findings provide critical cloud data for climate dynamics and weather process studies over the Tibetan Plateau, improve cloud parameterization in climate models, and offer valuable operational references for LHAASO wide field of view Cherenkov telescope observations.