利用陕甘宁地区22个气象观测站1961-2015年的冬季日气温资料,分析该地区的冬季气温变化,并依据中国国家标准《暖冬等级》,分析陕甘宁地区暖冬事件的变化特征,结果表明:近55年陕甘宁地区冬季平均气温呈明显的升高趋势,升幅为0.451 ℃/10a,1980年后冬季气温增加更加明显.区域暖冬指数表现为显著上升趋势,线性趋势为10％/10a,各站点的暖冬发生频率在22％～33％之间.陕甘宁地区区域性暖冬事件发生共16次(年),其中区域强暖冬事件共5次(年),暖冬强度最大、范围最广,暖冬现象存在2 a、4 a短时间以及9 a、15 a长时间振荡周期.利用NCEP再分析资料进一步分析表明,在温室效应导致全球变暖的大背景下,500 hpa位势高度场偏高,东亚大槽减弱,冷空气活动减弱以及厄尔尼诺现象的发生可能是造成陕甘宁地区暖冬事件发生的主要原因.%Using winter daily temperature data of 22 meteorological observation stations in Shaanxi-Gansu-Ningxia region during 1961 and 2015,the variations of winter temperature are analyzed.According to the China national standard,its warm winter characteristics are analyzed.The results show that its mean winter temperature has increased with a rate of 0.451 ℃/10a in recent half century,especially in recent 30 years.Regional warm winter index has a significant rising trend at a decadal rate of 10％and frequency of single station warm winter is 22％～33％.There are 19 regional warm winter years over the 55 years with 5 strong warm winters which is the most extensive and strongest.There exists the oscillation period of 3 years,5 years and 10 years in warm winter phenomenon.By using the NCEP reanalysis data,further analysis shows that under the background of global warming which caused by the greenhouse effect,the high temperature was caused by higher geopotential height at 500 hpa over Shaanxi-Gansu-Ningxia,weakening of the East Asian Trough at 500 hpa,less frequent activity of strong cold air current than those in normal years and the occurrence of El Nino phenomenon are probably the main reason of the warm winter events in the region.
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