人工站与自动站气温观测数据的对比分析

Contrast Analysis on Air Temperature Observations Between MWS and AWS

根据长沙2003年人工站和自动站的气温观测数据,分析其对比差值,发现:(1)长沙年平均气温对比差值为-0.17,即自动站的气温平均比人工站高0.17℃.对于短期气候预测,长沙自动站的气温观测数据是可用的,就气候研究来说,长沙自动站的气温观测数据是不可用的;(2)在一年四季中,长沙秋季和冬季的对比差值的绝对值都小于0.2.因而此时长沙自动站的气温观测数据可信且可用;春季和夏季的对比差值的绝对值都大于等于0.2,因而长沙自动站这两季的气温观测数据是不可靠的,必须慎重使用;(3)在一天中,长沙晚上和夜间的对比差值的绝对值都很小,因而自动站的观测数据是完全可信的;清晨和中午的对比差值的绝对值都比较大,因而此时的自动站数据不宜使用;(4)造成对比差值偏大的原因主要是自动站的仪器对冷空气活动和突然变化的天气不够敏感.因为对比差值的绝对值偏大的时候,都是冷空气活动的前后.

Using the air temperature observation data of manned-weather-stations （MWS） and auto-weatherstations（AWS） in Changsha city, we have carried out a contrast analysis on the differences of temperature observations between MWS and AWS, and found that 1 ） The annual mean air temperature difference is - 0.17, i. e. , the mean T of AWS is 0.17℃ higher then that of MWS, The air T observation data of AWS are usable for short term climate forecast, but are not for climate research. 2） In the four seasons of a year in Changsha differences are less than 0.2 in Autumn and Winter, therefore the T observations of AWS are reliable and usable, while those in Spring and Summer are greater than 0.2, therefore the T observations of AWS are not reliable and should be used with caution. 3） Within one day the difference is small in the evening and at night so the T observations are reliable, but in early morning and noon the difference is big, so the observations are not usable. 4） The main reason resul- ting in the big difference is that the equipments of AWS are not sensitive enough to the cold air activity and suddenly changing weather conditions. The big difference often occurs when cold air comes.