1961~2015年青藏高原极端气温事件的气候变化特征

利用1961~2015年CN05.1高分辨率的逐日最高、最低气温格点资料，计算6个极端气温指数（极端最高气温、极端最低气温、结冰日数、霜冻日数、暖日日数、冷夜日数），通过趋势分析和Mann-Kendall突变检验，考察青藏高原极端气温事件的时空变化规律。结果表明:青藏高原极端最高气温、极端最低气温的总体分布呈现西冷东暖的特征，与地形西高东低一致；该地区极端最高气温、极端最低气温及暖日日数均呈上升趋势，倾向率分别为0.25℃/10a、0.42℃/10a、2.14d/10a，极端最低气温的线性增温趋势较极端最高气温更为明显；而结冰日数、霜冻日数及冷夜日数均呈下降趋势，倾向率分别为?3.09d/10a、?4.75d/10a、?2.31d/10a；从空间分布看，青海地区极端最高气温的增温趋势最为显著，柴达木盆地是明显的升温中心；在时间变化上，极端最高气温、结冰日数、暖日日数均在1997年发生了突变。 

Climate Change Characteristics of Extreme Temperature Events in the Qinghai-Tibet Plateau from 1961 to 2015

With the high resolution lattice data (daily maximum and minimum temperatures) of CN05.1 from 1961 to 2015, 6 extreme temperature indexes were calculated. Through the trend analysis and Mann-Kendall (M-K) mutation test, the spatio-temporal varation of extreme temperature events in the Qinghai-Tibet Plateau is investigated. The results show that the overall distribution of extreme maximum temperature, extreme minimum temperature and warm diurnal index had an upward trend, and the tendency rates were 0.25℃/10a, 0.42℃/10a, 2.14d/10a. Compared with extreme maximum temperature, the linear warming trend of extreme minimum temperature was more obvious. The changes of ice index(ID), frost index(FD) and cold night index(TN10) showed a downward trend, the tendency rates were ?3.09d/10a, ?4.75d/10a, ?2.31d/10a. In terms of spatial distribution, the warm trend of extreme maximum temperature in Qinghai Province was the most significant, especially the Qaidam Basin was the warming center. In terms of temporal variation, the extreme maximum temperature, ice index(ID) and warm diunal index(TX90)has a sudden change in 1997.