The Frequency Variation Characteristics And Risk Regionalization Of Cold Wave Activity In China’s Oases From 1960 To 2016

The cold wave is one of the major catastrophic weather events in China in the winter months.A series of bad weather brought about by the outbreak will have a great impact on people’s production and life,and cause huge losses to the national economy.Oasis is the main support for human survival in desert areas.The survival and reproduction of humans in the desert regions,the formation and development of cultural customs,and the exchanges between regions are closely related to oasis.China’s oases is located in the hinterland of Eurasia,and it is close to the critical area of cold wave in central Siberia.Affected by the cold wave,its response to climate change is more sensitive than other regions,and is more complicated by climate change.Therefore,the adverse effects of the cold wave on the China’s oases are even more serious,and the losses caused will also be even greater.At present,the research of cold wave at home and abroad is mainly concentrated in three aspects,such as cold wave process,cold wave mechanism and cold wave prediction method,but there are few studies on the risk zoning of cold wave,and the research on the risk zoning of cold wave disaster in large area has not been seen yet.Therefore,this paper makes use of daily average temperature and minimum temperature data from 74 ground-based meteorological stations in China’s oases from 1960 to 2016 to analyze the changing trend and spatial distribution of cold wave activity in China’s oases for the past 57 years.Using the atmospheric circulation index,geographical parameters,and annual average temperature data,the factors affecting the cold wave changes in the China’s oases are analyzed.Finally,using daily average temperature and minimum temperature data,combined with socio-economic statistics and land-use data,risk assessment regionalization analysis was conducted on the China’s oases cold wave disasters.The main conclusions of this article are as follows:(1)The frequency of cold wave in China’s oases has shown a decreasing trend,which is about-0.13 times/10 a,and there is a significant regional difference.Except for the frequency of cold spells in Alxa oasis,the frequency of cold wave shows an increasing trend(about 0.19 times/10a),and that of other oasis areas.The frequency of cold wave shows a decreasing trend,but the decreasing trend of each oasis area is not the same.Among them,the decreasing trend of the northern Xinjiang oasis is the most significant,reaching-0.2 times/10 a.(2)The cold wave activity in China’s oases is mainly concentrated from September to May of the second year,and is the highest in November of each year and March of the following year.The frequency of autumn cold wave showed a downward trend,which was about-0.13 times/10 a,and the winter and spring cold wave frequency showed a slight upward trend,which were about 0.04 times /10 a and 0.05 times /10 a,respectively.(3)Through the correlation analysis with the nine atmospheric circulation indices,such as PVA,PVI,APVAI,APVII,CQ,AO,SHI,CA and TPI,we found that the frequency of cold wave of each site in China’s oases had a significant positive correlation with the CA during the interannual and seasonal seasons,with correlation coefficients of 0.479,0.308,0.416 and 0.367(p≤0.05),respectively.And it was significantly negatively correlated with the APVAI,the correlation coefficients were-0.359,-0.309,-0.341 and-0.276(p≤0.05).The cold wave frequency of each site in China’s oases and the SHI had a significant positive correlation only in winter.In the past 57 years,the latitude has increased by one degree every northward,and the frequency of cold wave increased 9.47 times in China’s oases,3.69 times in autumn,1.87 times in winter and 3.91 times in spring.In addition,the annual average temperature of the China’s oases has shown an increasing trend for 57 years,with a rate of 0.225℃ /10 a.The correlation between the frequency of cold wave and the annual average temperature is relatively high,and the correlation coefficient is 0.700(p≤ 0.01).(4)The risk zoning shows that in the past 57 years,most of the high-risk and second highest risk areas of the China’s oases are mainly located in the northern Xinjiang oasis,the Hexi Corridor oasis,and the Hetao Plain oasis.And the low-risk of the cold wave is mainly located in the southern Xinjiang oasis and the western Alxa oasis.