Enhanced Intensity of Interannual Variability of May Drought in Northeast China After 2000 and Its Connection With the Barents Sea Ice.

Using the standardized precipitation evapotranspiration index, this article demonstrates that the intensity of interannual variability (IIV) of May drought in Northeast China has enhanced remarkably after entering into the 21st century. Relative to 1980–1999, the percentage increase of IIV reaches 70% during 2000–2016. Such an enhancement is well supported by the intensification of IIVs in the East Asian polar front jet stream (EAPJ), East Asian subtropical jet stream (EASJ), and lower‐level anticyclonic circulation anomaly over Northeast China. Remarkable impact from the Barents Sea ice in April is also highlighted. With respect to the former period, a substantial increase occurs as well in the IIV of April Barents Sea ice during 2000–2016. Due to larger IIV in the latter period, the decline of April Barents Sea ice can exert evident effects on heat fluxes, consequently resulting in a significant increase of surface air temperature (SAT) in situ in May. The increased SAT further induces a wave train propagating southeastward to the East Asian region from the Barents Sea, which leads to a strengthened EAPJ and a weakened EASJ in the upper level, concomitant with an anomalous anticyclonic circulation covering Northeast China in the lower level. These atmospheric circulation anomalies link to the drought variability over Northeast China. Thus, the increase in the IIV of April Barents Sea ice favors the enhanced IIV of May drought in Northeast China. Plain Language Summary: Northeast China serves as an important granary in China. In recent decades, frequent occurrences of drought exert adverse effects on agriculture production and human lives in this region. Thus, better understanding of drought variability in Northeast China is an urgent need. In this study, we revealed an increase in the intensity of interannual variability (IIV) of May drought in Northeast China after 2000, which is well supported by the increased IIVs of the East Asian polar front jet stream, East Asian subtropical jet stream, and lower‐level anticyclonic circulation anomaly over Northeast China. Further examination suggested that the April Barents Sea ice with larger IIV after 2000 plays a pronounced role, by means of modulating the thermal conditions and associated wave train. The results are encouraging to improve the understanding about the interannual variability of drought in Northeast China, and act as a scientific basis for food security and human lives. Key Points: The intensity of interannual variability of May drought in Northeast China has enhanced after 2000Such an enhancement is supported by the intensified interannual variability of associated atmospheric circulationsThe Barents Sea ice variability in April plays a role through effects on the thermal condition [ABSTRACT FROM AUTHOR]