1961—2018年我国气温日较差日数的时空演变特征及区域差异

全球变暖背景下，学界对平均气温和极端气温关注较多，而对气温日较差研究相对较少。采用1961—2018年我国545个气象站点的观测数据，从均值、距平、变化趋势和波动特征等方面诊断气温日较差的时空分异特征。结果表明：（1）1961—2018年我国气温日较差日数随气温日较差数值的增大而减少。5 ℃、10 ℃和15 ℃气温日较差日数呈西北多、东南少的空间分异格局。（2）不同气温日较差日数距平随年代逐渐由以正距平为主演变为以负距平为主，并具有年代分异和次区域分异特征。（3）1961—2018年我国5 ℃、10 ℃、15 ℃和20 ℃气温日较差日数整体趋于减少。5 ℃和20 ℃气温日较差日数在西藏地区和黄淮东部地区趋于增加。（4）1961—2018年我国5 ℃、10 ℃和15 ℃气温日较差日数年际波动呈东南大、西北小的空间分异格局。15 ℃和20 ℃气温日较差日数年际波动最大，10 ℃次之，5 ℃最小。（5）我国青藏高原和东南部需高度关注因气温日较差引发的崩滑流风险，同时也必须充分考虑气温日较差变化给水利工程、油气管线和高铁建设等带来的风险。

Spatial and temporal variation characteristics and regional differences of days of diurnal temperature range in China from 1961 to 2018

Under the background of global warming, academia pays great attention to the average temperature and extreme temperature, but less attention to the diurnal temperature range. Based on the data from 545 meteorological stations in China from 1961 to 2018, this study diagnoses the spatial and temporal variability of diurnal temperature range from the aspects of mean, anomaly, variation trend and fluctuation characteristics. The results show that: Firstly, the days of diurnal temperature range in China from 1961 to 2018 tend to decrease with the increase of diurnal temperature range. The diurnal variation of temperature at 5 ℃, 10 ℃ and 15 ℃ is detected more in the northwest and less in the southeast. Secondly, following the development of the decade, the diurnal temperature range anomaly of different temperatures has gradually changed from positive anomaly to negative anomaly, and has the characteristics of decade and subregional differentiation. Thirdly, the number of days with diurnal temperature range at 5 ℃, 10 ℃, 15 ℃ and 20 ℃ in China tend to decrease as a whole from 1961 to 2018. The number of days with diurnal temperature range between 5 ℃ and 20 ℃ tended to increase in Tibet and Eastern Huanghuai region, respectively. Fourthly, the annual fluctuations of the days with diurnal temperature range at 5 ℃, 10 ℃ and 15 ℃ in China show a spatial pattern which exhibits large variation in the southeast and small in the northwest from 1961 to 2018. The annual fluctuation of the days with temperature diurnal range at 15 ℃ and 20 ℃ are the largest, followed by those at 10 ℃ and the smallest at 5 ℃. Fifthly, both the Qinghai-Tibet Plateau and the southeast of China should pay close attention to the risk of landslides caused by the variation of diurnal temperature range. At the same time, it is necessary to fully consider the risks brought by the change of daily temperature range to water conservancy projects, oil and gas pipelines and high-speed rail construction.