The solar radiation incident in a mountainous area with a complex terrain has a strong spatial heterogeneity due to the variations in slope orientation (self‐shading) and shadows cast by surrounding topography agents (topographic shading). Although slope self‐shading has been well studied and considered in most land surface and hydrological models, topographic shading is usually ignored, and its influence on the thermal and hydrological processes in a cold mountainous area remains unclear. In this study, a topographic solar radiation algorithm with consideration for both slope self‐shading and topographic shadows has been implemented and incorporated into a distributed hydrological model with physically based descriptions for the energy balance. A promising model performance was achieved according to a vigorous evaluation. In a control model without considering the topographic shadows, the simulated solar radiation incident in the study area was about 14.3 W/m2 higher on average, which in turn led to a higher simulated annual mean ground temperature at 4 m (by 0.41 °C) and evapotranspiration (by 16.1 mm/a), and a smaller permafrost extent (reduced by about 8%), as well as smaller maximal snow depth and shorter snow duration. Although the simulation was not significantly improved for discharge hydrograph in the base model, higher river runoff peaks and an increased runoff depth were obtained. In areas with a rugged terrain and deep valleys, the influences of topographic shadows would even be stronger in reality than the presented results, which cannot be ignored in the simulation of the thermal and hydrological processes, especially in a refined model.

Two ice cores were retrieved from high elevations (∼ 5800 m a.s.l.) at Mt. Nyainqentanglha and Mt. Geladaindong in the southern to inland Tibetan Plateau. The combined analysis of tritium ( 3 H), 210 Pb, mercury tracers, along with other chemical records, revealed that the two coring sites had not received net ice accumulation since at least the 5 1950s and 1980s, respectively, implying an annual ice loss rate of more than several hundred millimeter water equivalent over these periods. Both mass balance modeling at the sites and in situ data from nearby glaciers confirmed a continuously negative mass balance (or mass loss) in the region due to the dramatic warming in the last decades. Along with a recent report on Naimona'nyi Glacier in the Himalaya, the find-10 ings suggest that glacier decapitation (i.e., the loss of the accumulation zone) is a widespread phenomenon from the southern to inland Tibetan Plateau even at the summit regions. This raises concerns over the rapid rate of glacier ice loss and associated changes in surface glacier runoff, water availability, and sea levels. et al., 2012). In situ stake observations have also confirmed a continuously negative 419 Abstract Introduction Conclusions ReferencesTables central Asia (Bryson, 1986). The TP blocks mid-latitude westerlies, splitting the jet into two currents that flow the south and north of the plateau, respectively. The plateau is 420 Abstract Introduction Tables Abstract Introduction Conclusions References Tables Abstract Introduction Conclusions References Tables 25 Conclusions References