近地层日最高最低气温变化特征

最高、最低气温是反映气候冷暖变化程度的重要标志,是判断极端气候事件强度的重要指标。利用中国气象局兰州干旱气象研究所定西干旱气象与生态环境试验基地2003年10月17日至2004年4月6日1、2、4、10、16m温度梯度观测试验资料,分析研究了不同高度最高、最低气温的变化特点和出现时间的规律。结果表明:日最高气温从低层到高层是降低的,最低气温是升高的,并且随高度的变化符合指数或对数规律。最高气温出现时间一般在正午2.5 h后,有天气变化时在20:00后出现的情况较多;最低气温在2 m高度上最早出现,4 m以下在日出前出现的较多,4 m以上在日出后出现的较多。

Characteristics of Maximum and Minimum Temperature Variation in Near Surface Layer

Maximum and minimum temperature can be used as a key indicator or index for climate change or the intensity of an extreme climatic event.By using the observational temperature gradient data at the heights of 1,2,4,10,16 m obtained in the Dingxi Arid Meteorological and Environment Experimental Base from 17 October 2003 to 6 April 2004,the characteristics of maximum and minimum temperature changes were analyzed.The results show that daily maximum temperature decreased from lower layer to upper layer,while the minimum temperature increased,which accords with the law of exponent/logarithm.The maximum temperature appeared(2.5) hours after the noon,and if there was a severe weather event,the maximum mostly appeared after 20:00.The minimum temperature appeared first at the height of 2 m,and mostly appeared before sunrise at the heights lower than 4 m while appeared after sunrise at the heights higher than 4 m.