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Over‐estimation of summer precipitation over the Tibetan Plateau (TP) is a well‐known and persistent problem in most climate models. This study demonstrates the impact of a Gaussian Probability Density Function cloud fraction scheme on rainfall simulations using the Weather Research and Forecasting model. It is found that this scheme in both 0.1° and 0.05° resolutions significantly reduces the wet bias through both local feedbacks and large‐scale dynamic process. Specifically, increased cloud water/ice content with this scheme reduces surface shortwave radiation, and consequently surface heat fluxes and evapotranspiration. This, in turn, dampens the large‐scale thermal effect of the TP and weakens the exaggerated monsoon circulation and low‐level moisture convergence. It is this large‐scale dynamic process that contributes the most (∼70%) to the wet bias reduction. Although this paper presents a modeling study, it highlights the cloud radiative feedback to the large‐scale dynamics and precipitation over the TP. Plain Language Summary: Despite numerous attempts to correct the overestimation of summer precipitation over the Tibetan Plateau (TP) in current global and regional climate models, the issue persists. This study applies the Gaussian Probability Density Function (GPDF) cloud fraction scheme in the Weather Research and Forecasting model at two different resolutions (0.1° and 0.05°) during a summer over the TP. The results show that the GPDF scheme significantly mitigates the precipitation overestimation, particularly in the high‐resolution modeling. We explored the physical processes, both local and remote, that contribute to this improvement. Specifically, an increase in cloudiness reduces the amount of radiation reaching the land surface. This decrease in surface radiative heating not only reduces local evaporation but also weakens the thermal effect of the TP. The latter is a major driver of the South Asian monsoon that conveys moisture to the TP, and its weakening reduces moisture convergence over the TP. Both the decreases in local evaporation and remote moisture convergence contribute to the alleviation of the precipitation overestimation, and the latter plays a dominant role. These findings provide a unique perspective for reducing the wet bias over the TP, focusing on the surface available energy and associated remote moisture processes. Key Points: The use of the Gaussian Probability Density Function cloud fraction scheme in high resolution greatly reduces wet bias over the Tibetan Plateau (TP) during summerMore cloud water/ice with the scheme lessens TP's thermal effect, causing a weaker South Asian monsoon and moisture convergenceWet bias reduction is mainly governed by the decrease in remote moisture rather than local evapotranspiration [ABSTRACT FROM AUTHOR]

Understanding cloud distribution over lakes is crucial to determine input radiation and precipitation for lake thermal and water balance processes. Based on Himawari‐8 satellite observation and Weather Research and Forecasting model results, this study examines the influences of lakes on daytime cloud cover during warm seasons over the Tibetan Plateau (TP), which is home to thousands of lakes. Observation shows the existence of cloud holes and narrow cloud rings around the lakes, that is, fewer clouds over the lakes and more clouds along the shoreline, which has rarely been reported and is considered typical to TP by comparison with lakes outside of TP. The threshold size of lakes that can produce the shoreline cloud ring is identified to be about 300 km2, as a conservative estimate. We further highlight the importance of atmosphere advection/background wind in the formation of lake‐associated clouds. Lake breeze forms under weak background winds and the downdraft branch inhibits cloud formation over the lakes; while the updraft branch causes convection to form clouds over lakeshores. However, strong background winds do not favor lake breeze formation, changing cloud distribution over the lakes. Fewer clouds are also found in the downwind regions, and this influence is at a distance comparable to the lake scale. Due to fewer clouds over lakes, shortwave radiation is significantly larger (∼100 W/m2) and longwave radiation is smaller (∼a few W/m2) than that of the further land region. Therefore, the above observational facts provide a new perspective to advance the understanding of lake‐air interactions. Plain Language Summary: There are lots of lakes over the Tibetan Plateau (TP), but the influence of these lakes on cloud during warm seasons remain unclear. Satellite data shows the existence of cloud holes and narrow cloud rings around the lakes, that is, fewer clouds over the lakes and more clouds along the shoreline, which has rarely been reported before. Simulation results demonstrate that the lake breeze accounts for this phenomenon: air descends over the lake, which inhibits cloud formation, while ascending branch over the shoreline favors cloud formation. Lakes over 300 km2 can yield these cloud influences, so this area is thought as the threshold area that lakes can have influence on atmosphere. Clouds in the downwind regions are also fewer under the influence of background wind, and this influencing distance is almost equal to the lake scale itself. Due to less block by clouds, solar radiation is much higher over the lake than surrounding land, but downward longwave radiation is a little lower because of less emission from the cloud bottom, resulting an increase of net radiation in total at the lake surface. The conclusions of this study can help understand energy and hydrology processes of lakes better over the TP. Key Points: Evident "cloud holes" and "cloud rings" are found for lakes over the Tibetan Plateau, which are mainly induced by lake breezeClouds in the downwind regions are also fewer due to atmosphere advection; this distance is almost equal to the size of the lake itselfFewer clouds over the lake increase the net radiation mainly due to much higher downward shortwave radiation [ABSTRACT FROM AUTHOR]

Investigation of the variations of hydrological cycles during the Last Interglacial (130–115 ka; LIG) may deepen our understanding of climate change in a warmer‐than‐present world induced by Earth's orbit. Here we revealed an intensified atmospheric branch of the hydrological cycle over the Tibetan Plateau (TP) in summer during the LIG relative to the preindustrial period, using the mesoscale Weather Research and Forecasting model driven by the Community Earth System Model. Our results showed that precipitation over the TP increased by 5.65 × 107 kg s−1, with 63.2% of the increase contributed by advected moisture transports, and the remaining 36.8% caused by local moisture recycling processes. As for advected moisture transports, the inflow increased by 1.93 × 107 kg s−1 and the outflow decreased by 0.87 × 107 kg s−1, respectively. Variations of the moisture transport were more profound at the eastern and northern edges, which were linked with changes in Indian summer monsoon and westerly jets. Regarding local moisture recycling processes, evaporation enhanced by 2.85 × 107 kg s−1 over the TP, influenced by variations in surface air temperature, surface net radiation flux, surface relative humidity, and surface wind fields. Increased evaporation accompanied by enhanced moisture inflow resulted in an enriched precipitation recycling ratio of ∼1% over the TP during the LIG relative to the preindustrial in summer. Our results aid in understanding the atmospheric branch of the hydrological cycle over the TP in an orbit‐induced warmer world and shed light on the future evolution of the hydrological cycle over the TP at multi‐millennial and orbital timescale. Key Points: Dynamical downscaling simulations for the Last Interglacial from Weather Research and Forecasting driven by Community Earth System ModelIntensified atmospheric branch of the summer hydrological cycle over the Tibetan Plateau during the Last Interglacial (LIG)Intensified hydrological cycle was manifested in both external and internal cycles during the LIG [ABSTRACT FROM AUTHOR]

Numerical simulations often overpredict precipitation over the Tibetan Plateau (TP). To examine the factors causing precipitation overprediction, different parameterizations of liquid‐phase microphysical processes (accretion, autoconversion, and entrainment mixing) are implemented into the Morrison microphysics scheme to simulate a TP precipitation event in summer with the Weather Research and Forecasting (WRF) model. The general spatial distribution and temporal trend of precipitation are captured by all simulations, but the precipitation rate is overpredicted. The results from sensitivity experiments suggest that compared to other examined liquid‐phase processes, the accretion process is more important in precipitation simulation over the TP region. Further investigation with the Heidke skill scores reveals that accretion parameterization that takes into account the raindrop size produces the most accurate results in terms of the total surface precipitation. This parameterization suppresses spurious accretion and does not produce liquid‐phase precipitation until cloud droplets are big enough. It is also confirmed that increasing the model resolution can reduce precipitation overprediction. Results from the case study are confirmed by the use of a 1‐month simulation. Key Points: The accretion process plays more important roles than other examined liquid‐phase processesConsidering raindrop size in accretion process suppresses liquid‐phase rain and mitigates the overprediction of precipitation over the TPIncreasing the model resolution can reduce precipitation overprediction [ABSTRACT FROM AUTHOR]