<p><span>The southeastern Tibetan Plateau (SETP) is the most predominant summer rainfall region in the Tibetan Plateau. However, the atmospheric circulation characteristics associated with regional heavy precipitation over the SETP are still unclear. Based on 35 years of daily precipitation observations in 1980</span><span>-</span><span>2014, the types of weather systems causing regional heavy precipitation events over the SETP are objectively classified into two representative patterns, named the Tibetan Plateau vortex type (TPVT) and mid-latitude trough type (MLTT), through hierarchical clustering technique. The classification results show a clear connection between the heavy precipitation and the positive vorticity anomaly, moisture convergence, and southeastward shift of the westerly jet core contributing to anomalous rising motion. It was found that TPVT and MLTT resulting in heavy precipitation events were derived from the eastward development of the Tibetan Plateau vortex related to dry-wet potential vorticity processes and the penetration of deep extratropical trough-ridge circulations, respectively. </span></p>

<p>Precipitation studies suggest an accelerated water cycle over the Tibetan Plateau (TP) in recent decades. However, the exact changes to evapotranspiration (ET<sub>a</sub>) over this period remain largely unknown. Multiple ET<sub>a</sub> products for the TP region report that ET<sub>a</sub> experienced a significant increasing trend of around 8.4 ± 2.2 mm/10 a during 1982–2018. Here, we quantified and explained the ET<sub>a</sub> trend using a comprehensive process-based ET<sub>a</sub> model refined on ground-based observations over the TP. Attribution analysis revealed that a large part of the increasing ET<sub>a</sub> trend was caused by higher temperature (53.8%) and more soil moisture (23.1%) caused by the melting cryosphere and increased precipitation. The increasing rate of ET<sub>a</sub> on the TP was approximately twice that of the global ET<sub>a</sub>, providing strong and independent evidence for an accelerated hydrological cycle. The dominant role of increased temperature in ET<sub>a</sub> implies a continued acceleration of the water cycle in the future.</p>

The Yarlung Tsangbo Grand Canyon (YGC), one of the world's deepest canyons, is located within the East Himalayas, which are remote and poorly instrumented. In this study, a rain gauge network was established around the YGC region. Data collected from the network for more than three years disclose that the rainfall spatial pattern in the south of the YGC region is relatively homogeneous. Diurnal cycles showed some variations among sites, but a clear floor was visible in the afternoon and peak values were exhibited in the early morning.The monthly precipitation in the YGC region shows two peaks, in April and July.There are two regions (500 m and 2,500 m AMSL) with high precipitation in the YGC. For rainfall extremes, vertical convection and vapor transport are important in this region. The diurnal cycle from our observations provides a key test of the physical parameterizations for use in the fifth-generation ECMWF (European Centre for Medium-Range Weather Forecasts) reanalysis product (ERA5).Our observations indicate that ERA5 cannot reproduce the diurnal patterns of precipitation in the YGC region. ERA5 showed a wet bias when estimating light cumulus rainfall and a dry bias when estimating heavier (convective) precipitation. The erroneous diurnal variation of ERA5 precipitation (false afternoon rainfall) was due to the CAPE (Convectively Available Potential Energy)-based convective precipitation scheme. The higher ERA5 precipitation than observed was due to the large-scale rainfall scheme in the Integrated Forecasting System (IFS) of ERA5. These findings indicate that there still is room for improvement of the ERA5 reanalysis data in the eastern Himalaya region.