Attribution of drought trends on the Mongolian Plateau over the past decades

Abstract

The Mongolian Plateau (MP) has undergone a significant drought trend in recent decades, presenting a substantial threat to local ecosystems and environments. The debate persists on whether this observed drought trend stems from external forcings or is a result of internal variability. Utilizing the large-ensemble simulations of the climate model and dynamical adjustment method, we have identified that the atmospheric circulation anomalies are the main drivers of drought trends in MP. A zonal atmospheric wave train, triggered by internally-generated warming of the North Atlantic sea surface temperature (NAS), is responsible for nearly 57% of the drought trend observed in MP. While external forcings could potentially induce a moistening trend in MP via direct thermodynamic processes, the atmospheric circulation anomalies linked to the forced NAS warming can not only offset its direct effect but also further amplify the drought trend in MP, accounting for 43% of the drought trend observed in MP.