Inaccurate characterization of complex topography leads to the wet bias in climate models, particularly affecting terrain effects in regions like the Tibetan Plateau (TP). This study utilizes the Weather Research and Forecasting (WRF) model with multiple terrain datasets and introduces the terrain complexity index (TCI) to quantify the degree of terrain changes, aiming to evaluate how terrain complexity affects the cloud and precipitation processes over the TP. The results indicate that fine terrain complexity primarily causes earlier cloud formation and precipitation, resulting in more heavy precipitation on the southern slope of the TP (SSTP) and more light precipitation on the TP platform. The structure of moisture transport and microphysical processes further reveals that this promotes the formation of more medium and high clouds, increasing the proportion of solid precipitation over the SSTP. Over the TP platform, the restriction of medium and high cloud development with enhancing the proportion of low clouds for more liquid precipitation. These findings deepen the understanding of the TP’s complex terrain effect on cloud and precipitation changes in the Asian water cycle.

The influence of surface heat fluxes on the generation and development of cloud and precipitation and its relative importance to the large-scale circulation patterns are investigated via cloud-resolving model (CRM) simulations over the Tibetan Plateau (TP) during boreal summer. Over the lowland (e.g., along the middle and lower reaches of the Yangtze River), the dynamical and thermal properties of the atmosphere take more responsibility than the surface heat fluxes for the triggering of heavy rainfall events. However, the surface thermal driving force is a necessary criterion for the triggering of heavy rainfall in the eastern and western TP (ETP and WTP). Strong surface heat fluxes can trigger shallow convections in the TP. Furthermore, moisture that is mainly transported from the southern tropical ocean has a greater influence on the heavy rainfall events of the WTP than those of the ETP. Cloud microphysical processes are substantially less active and heavy rainfall cannot be produced when surface heat fluxes are weakened by half in magnitude over the TP. In addition, surface heating effects are largely responsible for the high occurrence frequency of convection during the afternoon, and the cloud tops of convective systems show a positive relationship with the intensity of surface heat fluxes.

Observations and simulations have shown that the Tibetan Plateau (TP) plays an important role in the climate and weather of East Asia. Uncertainties in reanalysis data sets have been documented by comparing them with independent rawinsonde data, but the impacts of incorporating this data into a reanalysis data set on the dynamical and thermodynamical features over the TP have not been assessed. Observations from the recent Third Tibetan Plateau Atmospheric Scientific Experiment (TIPEX‐III) can be used to evaluate the Eastern TP ERA‐Interim reanalysis data set (ERA). In this study, the Barnes objective analysis scheme is used to incorporate the rawinsonde data into the ERA to acquire the gridded data (OBJ) for examining heat and moisture budgets. It is shown that the OBJ budget‐estimated rainfall intensity is better correlated with the observations than the ERA budget‐estimated rainfall intensity. The ERA overestimates weak rainfall but underestimates heavy rainfall. The incorporation of special rawinsonde into the OBJ impacts the dynamical and thermodynamical characteristics both spatially and temporally. The downward motion and cooling are enhanced over the rainless regions/periods, while the upward motion and heating are enhanced over the rainy regions/periods. The rawinsonde effect is stronger with the increasing rainfall intensity. The differences of spatial distributions and temporal variations in heating between the OBJ and ERA are primarily determined by the vertical advection terms in heat and moisture budgets. The OBJ‐derived large‐scale forcing is essential for cloud‐resolving model simulations of TP cloud systems. The above conclusions can also be applied to the ERA5.

The entrainment rate (λ) is difficult to estimate, and its uncertainties cause a significant error in convection parameterization and precipitation simulation, especially over the Tibetan Plateau, where observations are scarce. The λ over the Tibetan Plateau, and its adjacent regions, is estimated for the first time using five-year satellite data and a reanalysis dataset. The λ and cloud base environmental relative humidity (RH) decrease with an increase in terrain height. Quantitatively, the correlation between λ and RH changes from positive at low terrain heights to negative at high terrain heights, and the underlying mechanisms are here interpreted. When the terrain height is below 1 km, large RH decreases the difference in moist static energy (MSE) between the clouds and the environment and increases λ. When the terrain height is above 1 km, the correlation between λ and RH is related to the difference between MSE turning point and cloud base, because of decreases in specific humidity near the surface with increasing terrain height. These results enhance the theoretical understanding of the factors affecting λ and pave the way for improving the parameterization of λ.

The Tibetan Plateau (TP) experiences a particular dynamical and thermal environment due to its unique topography, which could affect the generation and development of its cloud and precipitation. Statistical results of 52‐year daily precipitation (1961 to 2012) show that the most frequent daily precipitation is about 3 mm day⁻¹ over the eastern TP (ETP) in the warm season while it is less than 1 mm day⁻¹ over the western TP (WTP). Circulation patterns for rainy and rainless conditions over both the ETP and WTP are investigated. The results show that the rainy weather over the TP is usually related to the moisture transported from the warm ocean by the southerly flow. Moreover, rainy weather in WTP can only appear when the strong southerly flow prevails over the Indian subcontinent. When the south flow is weak, the rainy weather can still develop in ETP under favorable conditions due to the local madid environment. CloudSat observations show that the strong convective system can extend to a level as high as 16 km above the sea level with a favorable dynamical and thermal environment. However, the depth of most precipitating convective clouds over the TP is in a range of 6–9 km. Due to the wetter condition, the precipitating convective cloud holds a lower cloud base in August in ETP than WTP. Compared with other regions, the precipitating convective clouds in both the ETP and WTP are thinner in cloud depth, smaller in cloud particles and weaker in precipitation capacity.