A spatial–temporal analysis of cold surge days in northern China during 1960–2016

Cold surges are one of the most devastating natural hazards that frequently affect northern China. In order to evaluate this extreme weather event in global warming, the spatial–temporal characteristics of cold surge days were analyzed based on the daily minimum temperature data of 330 stations in northern China during 1960−2016. Results revealed the spatial distribution of cold surge days increased from southwest to northeast. The spatial trend of cold surge days decreased in most part of northern China. Time series of cold surge days decreased during 1960−2016. The cold surge days during 1960−1985 were obviously higher than that of during 1986−2016. In general, regions with high standard deviation correspond to large number of cold surge days and strong decrease trend of cold surge days, implying strong instability and high probability of extreme cold surge occurrences in those regions. The wavelet analyses showed primary period of cold surge days varied from regions. Additionally, the correlation analysis revealed Asia Polar Vortex Area Index, Asia Polar Vortex Intensity Index, Arctic Oscillation and North Atlantic Oscillation showed much stronger association with cold surge days than El Niño–Southern Oscillation and Pacific Decadal Oscillation. The atmospheric circulation indicated a warmer condition in northern China during 1986−2016 compared to that of during 1960−1985, partly explained higher cold surge days for the period 1960−1985.