Possible linkage between winter extreme low temperature over
central-western China and autumn sea ice loss
Abstract
Based on reanalysis datasets and sea-ice sensitivity experiments, this
study has pointed out that the autumn sea ice loss in East
Siberian-Chukchi-Beaufort (EsCB) Seas significantly increases the
frequency of winter extreme low temperature over western-central China.
Autumn sea ice loss warms the troposphere and generates anticyclonic
anomaly over the Arctic region one month later. Under the effects of
synoptic eddy-mean flow interaction and anomalous upward propagated
planetary wave 2, the Arctic anticyclonic anomaly strengthens and
develops toward Greenland-Northern Europe, accompanied by a weakened
stratospheric polar vortex. In winter, following intra-seasonal downward
propagation of stratospheric anomalies, the Northern European positive
geopotential anomalies enhance and expand downstream within 7 days,
favoring Arctic cold air east of Novaya Zemlya southward (hyperpolar
path) accumulating in Siberia around Lake of Baikal. In the subsequent
2~3 days, these cold anomalies rapidly intrude
western-central China and induce abrupt sharp cooling, thus more
frequent extreme low temperature there.