The Extreme Spring Drought Over Northern China in 2022: Characteristics and Possible Mechanisms

ABSTRACTIn spring of 2022, northern China experienced much warmer temperatures and a severe precipitation deficit, which led to an extreme drought over the region. Our analysis indicates that this extreme spring drought is associated with the extreme La Niña event and unprecedented warming sea surface temperature (SST) anomalies in the mid‐latitude North Pacific and North Atlantic. On the interannual time scale, the La Niña could lead to an anomalous cyclone over the western North Pacific and strengthen the southern part of the East Asian trough. The resultant downward motion and water vapour divergence anomalies dominate northern China, which cause an increase in air temperature and potential evapotranspiration (PET) and a decrease in precipitation, consequently intensifying the spring drought over northern China. In contrast, the warm SST anomalies over the mid‐latitude North Pacific and North Atlantic influence the northern China spring drought on the interdecadal time scale. Both the warm SST anomalies over the two oceans are related to a Rossby wave train that causes an anomalous anticyclone over the upstream of northern China. As a result, there are anomalous downward motions over northern China, favouring the increase in regional air temperature and PET. Accordingly, the warm SST anomalies over the mid‐latitude North Pacific and North Atlantic could aggravate the spring drought over northern China. Leave‐one‐out validation analysis indicates that the aforementioned SST anomalies are potential predictors for the spring drought over northern China.