[A-AS02] Extreme Events: Observations and Modeling

[AAS02-06] Attribution of atmospheric circulation variations associated with winter temperature whiplash events over Northeast China

*Zhen Liao¹, Panmao Zhai¹, Yang Chen¹ (1.LaSW, CAMS, China)

Keywords:attribution, compound event, circulation

Based on the daily meteorological observations, reanalysis and model datasets, this study investigated the evolution and the causes of the extreme cold events in Northeast China via a ‘temperature whiplash’ index over 1980-2018 from the perspective of the temperature variability and associated circulation. Results indicate that winters in Northeast China have become increasingly volatile during 1980-2018 based on the interdiurnal temperature variation. Such enhanced volatility has a strong expression in significant increases in whiplash events, which characterizes rapid and drastic switches between warm and cold extremes within several days. And cold extremes in these areas are more likely to occur in the form of the whiplash events under global warming background. At the same time, the increased whiplash events in Northeast China have a good relationship with the enhanced winter 500 hPa geopotential height variance over the Sea of Okhotsk. Further, the attribution analysis of the associated circulation variance by using HadGEM3-A-N216 ensembles shows that the observed changes in the winter 500 hPa geopotential height variance over the Sea of Okhotsk can attribute to the anthropogenic forcing, implying that the anthropogenic forcing has an impact on the associated circulation and thus lead to the increased the whiplash events in Northeast China.