1954～2011年乌拉特中旗日照时数的特征分析

采用气候倾向率方法对乌拉特中旗1954～2011年的年、季日照时数变化趋势进行了分析。结果表明,近58年乌拉特中旗年和各季节日照时数均存在不同程度的减少趋势,年日照时数以2.378 h/10a速率减少,且这种减少趋势在增大,主要表现在秋、冬季。20世纪50～90年代年日照时数均为正距平,21世纪初以负距平为主;80年代秋季日照时数偏少,其他不同年代秋季均日照充足。年日照时数以异常偏多为主,仅在21世纪初出现异常偏少年,季日照时数无明显差异。50、60年代至今乌拉特中旗年平均总云量、低云量均表现为减少趋势,而80年代至今年平均总云量和低云量则呈增加趋势,以总云量增幅更大,平均增幅为1.6成/10a。

Characteristic Analysis on Sunshine Hours in Urat Middle County from 1954 to 2011

The variation trends of annual and seasonal sunshine hours in Urat Middle County from 1954 to 2011 were analyzed by climate trend rate method. The result indicated that the yearly and seasonal sunshine hours existed different decreasing trends in Urat Middle County in re- cent 58 years, the yearly sunshine hours is decreasing at the trend rate of 2. 378 h/lOa and the tendency is increasing which displayed mainly in autumn and winter. The yearly sunshine hours are all positive anomaly from the 50~ to the 90b in 20 century, its main inter-decadal varia- tion is negative anomaly at the beginning of the 21 st century ; the autumn sunshine hours in 1980s were less, the autumn sunshine are all abun- dant in the other different eras. Year sunshine hours are mainly abnormal more, abnormal less year appeared only in the 21st century, there is no obvious difference in seasonal sunshine hours. From the fifties to now, annual average total cloud cover and low cloud amount in Urat Mid- dle County are all shown as decreasing trend, while 1980s to now, annual average total cloud cover and low cloud amount showed an increas- ing trend, among them total cloud cover had a bi~ rate of increase amplitude, which had an increase amolitude of 1.6 oercent/lOa.