透视中国地表温度极端值的空间格局演变特征

Spatial pattern of ground surface temperature extremes in China

地表温度是地表与大气相互作用过程中的关键参量,在农业、水文、生态、环境等许多领域的研究中具有重要意义。文中基于1961~2018年中国545个气象站点地表温度的观测资料,从气候态特征、变化趋势和波动特征角度分析中国平均地温、极端最高地温和极端最低地温的时空演变特征。结果表明:1)1961~2018年中国平均地温和极端最低地温与纬度和海拔分别具有正相关和负相关关系。全国多数地区的极端最高地温普遍超过了60℃。1991~2018年全国平均地温和极端最低地温相比1961~1990年明显偏高,而极端最高地温则呈现出东南偏低、西北偏高的差异特征。2)1961~2018年中国极端最低地温增加趋势最大,平均地温次之,极端最高地温最小。平均地温和极端最低地温的增加趋势在高纬度地区超过了0.6℃/10a,明显超过了其它地区。极端最高地温呈现东南减少、西北增加的趋势分异规律。1990年前后对比表明中国三种地温整体以增加趋势为主,且1991~2018年的增加幅度整体高于1961~1990年。3)1961~2018年中国平均地温在高纬度和高海拔地区波动较大。极端最高地温在青藏高原、东北和东南沿海省份波动较大。极端最低地温波动特征随纬度增加而减小。在1990年前后的趋势差异表明中国平均地温波动特征在东北北部、青藏高原北部、新疆中部地偏大。极端最高地温在东南沿海和东北地区偏大,极端最低地温波动特征在华南南部偏北地区、云南南部、四川东部明显偏大。

Ground surface temperature is a key parameter in the process of surface-atmosphere interaction and is of great importance in many fields of research such as agriculture, hydrology, ecology and environment. Based on the yearly value data of 0 cm ground surface temperature of 545 meteorological stations in China from 1961 to 2018, the temporal and spatial evolution characteristics of 0 cm average ground surface temperature, extreme maximum ground surface temperature and extreme minimum ground surface temperature in China were analyzed from the perspective of climate state, changing trends and fluctuation feathers, and the temporal difference characteristics of the three ground surface temperatures before and after 1990 were compared. The results showed that: 1) Average ground surface temperature and extreme minimum ground surface temperature had positive and negative correlation with latitude and altitude respectively in China from 1961 to 2018. The extreme maximum ground surface temperature in most areas of China generally exceeded 60℃. Compared with 1961-1990, the average ground surface temperature and the extreme minimum ground surface temperature in China during 1991~2018 were significantly higher, while the extreme highest ground surface temperature showed the characteristics of lower in the southeast and higher in the northwest. 2) The increasing trend of extreme minimum ground surface temperature in China was the largest from 1961 to 2018, the average ground surface temperature was the second, and the extreme maximum ground surface temperature was the smallest. The increasing trend of average ground surface temperature and extreme minimum ground surface temperature in high latitude area were more than 0.6℃/10 a, obviously more than other areas in China. The extreme maximum ground surface temperature showed decreasing trend in the southeast China and increasing trend in the northwest China. The comparison before and after 1990 showed that the three ground surface temperatures in China were mainly increasing, and the increasing rate in 1991-2018 were higher than that in 1961-1990. 3) The average ground surface temperature in China fluctuated greatly in high latitude and high altitude areas from 1961 to 2018. The extreme maximum ground surface temperature fluctuated greatly in Qinghai Tibet Plateau, northeast China and southeast coastal provinces. The fluctuation of extreme minimum ground surface temperature decreased with the increase of latitude. The fluctuation difference before and after 1990 showed that the fluctuation of average ground surface temperature in China was larger in the north of northeast China, the north of Qinghai Tibet Plateau and the middle of Xinjiang. The fluctuation of extreme maximum ground surface temperature was larger in the southeast coastal area and the northeast China, and the extreme minimum ground surface temperature fluctuation was larger in the south by north area of South China, the south of Yunnan and the east of Sichuan.