Black carbon (BC) in snow/ice induces enhanced snow and glacier melting. As over 60% of atmospheric BC is emitted from anthropogenic sources, which directly impacts the distribution and concentration of BC in snow/ice, it is essential to assess the origin of anthropogenic BC transported to the Tibetan Plateau (TP) where there are few direct emissions attributable to local human activities. In this study, we used a regional climate‐atmospheric chemistry model and a set of BC scenarios for quantitative evaluation of the impact of anthropogenic BC from various sources and its climate effects over the TP in 2013. The results showed that the model performed well in terms of climatology, aerosol optical properties, and near‐surface concentrations, which indicates that this modeling framework is appropriate to characterize anthropogenic BC source‐receptor relationships over the TP. The simulated surface concentration associated with the anthropogenic sources showed seasonal differences. In the monsoon season, the contribution of anthropogenic BC was less than in the nonmonsoon season. In the nonmonsoon season, westerly winds prevailed and transported BC from central Asia and north India to the western TP. In the monsoon season, BC aerosol was transported to the middle‐upper troposphere over the Indo‐Gangetic Plain and crossed the Himalayas via southwesterly winds. The majority of anthropogenic BC over the TP was transported from South Asia, which contributed to 40%–80% (mean of 61.3%) of surface BC in the nonmonsoon season, and 10%–50% (mean of 19.4%) in the monsoon season. For the northeastern TP, anthropogenic BC from eastern China accounted for less than 10% of the total in the nonmonsoon season but can be up to 50% in the monsoon season. Averaged over the TP, the eastern China anthropogenic sources accounted for 6.2% and 8.4% of surface BC in the nonmonsoon and monsoon seasons, respectively. The anthropogenic BC induced negative radiative forcing and cooling effects at the near surface over the TP.

An analysis of the spatiotemporal variability in summer precipitation during the period 1961-2010 is presented based on monthly precipitation datasets from 66 meteorological stations in the central and eastern Tibetan Plateau (TP). By applying empirical orthogonal function (EOF) analysis, a strong reversal is found in the variability of summer precipitation between the northeastern and the southeastern TP on the inter-annual timescale; this reversal is defined as the Dipole Oscillation in summer precipitation over the TP.Our analysis shows that the North Atlantic Oscillation (NAO) greatly controls the Dipole Oscillation in TP summer precipitation by modifying the atmospheric circulation over and around the TP. With the increased stationary wave activity spreading eastward from the North Atlantic to the TP, a pronounced wave train pattern bridges the North Atlantic Ocean and the TP. During the positive phase of the NAO, warm moist air from the oceans around Asia is transported by the southeastern flank of the anticyclonic anomaly over East Asia to the northeastern TP. This northward-moving warm moist air encounters cold air masses transported by the northwestern flank of the cyclonic anomaly over the northeastern TP. The confluence of the cold and warm air masses subsequently strengthens cumulus convective activities and ultimately results in excessive precipitation over the northeastern TP. Meanwhile, as a cyclonic anomaly sets up over northwestern India and Pakistan, water vapour condenses into precipitation over northwestern India and Pakistan, inhibiting Arabian Sea moisture inflows into the southeastern TP and northeastern India. As a result, a precipitation deficit occurs over the southeastern TP. The opposite scenario occurs during the negative phase of the NAO.

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