Extreme drought in the recent two decades in northern China resulting from Eurasian warming

Abstract

The analysis of 55-year daily precipitation data reveals prolonging in consecutive dry-day (CDD) and extreme summertime droughts in northern China since the 1990s. Anomalous CDD corresponds to a persistent anticyclone anomaly, that has a significant correlation with enhancing in Eurasian forced waves including Eurasian teleconnection (EU) pattern and Silk Road pattern (SRP), which have response to the upward wave activity flux over the key region (40°N–70°N, 0°E–60°E) and other regions along the EU and SRP over Eurasia. Those are the partly significant forcing sources converting energy for the forced wave. It is hypothesized that increasing Eurasian heating is more notable with global warming, and it leads to increasing atmospheric baroclinicity in the lower troposphere, further for increasing wave activity flux, that is responsible for the enhancing EU and SRP, and finally contributes to enhancing anticyclone anomaly over northern China. These anomalous circulations may result in prolonging CDD and persistent summertime drought under anthropogenic warming as projected by global climate models.