银川市日照时数气候变化特征分析

利用银川市近53 a日照时数实测资料,分析了银川市日照时数年代际、年际、各季和各月的气候变化特征;并利用线性倾向估计法、滑动t检验法对银川市日照时数的年、季、月气候变化趋势进行了突变分析;同时利用年大于50 km能见度资料,验证银川市大气中空气污染物的逐渐增多,使能见度和日照时数变化趋势相似.结果表明:银川市年、季、月日照时数均呈减少趋势.

Analysis on Climate Change Characteristics of Sunshine Duration in Yinchuan City

In this paper,the climate change characteristics of decade,annual,seasonal and monthly sunshine durations in Yinchuan City are analyzed based on the observed data of sunshine duration in the city in recent 53 years;the saltations of annual,seasonal and monthly sunshine durations in Yinchuan City are analyzed using the linear trend estimation and moving t-test;and it is validated using the data of visibility >50 km that the air pollution becomes more serious and the trend of visibility is similar to that of sunshine duration.The results are as follows:(1) The annual,seasonal and monthly sunshine durations in Yinchuan City have been in a decrease trend since recent 53 years;seasonally,the reduction of sunshine duration is the most in winter but the least in summer,and monthly,it is the most in January but the least in August;(2) The results of moving t-test reveal that the saltation of sunshine duration is significant in winter,then in spring,but it is not so significant in summer and autumn;monthly,it is significant in January,February,March,April,October and December,especially in January,February and December;(3) The saltations of annual,seasonal and monthly sunshine durations in Yinchuan City occurred around 1980;(4) Affected by global warming and urbanization,the contents of atmospheric floating dust grains,aerosol grains,etc.over Yinchuan City are gradually increased,thus, the visibility and sunshine duration are decreased.The trend of visibility >50 km is similar to that of sunshine duration,that is they were in positive anomalies but in a reduction trend before 1980,and have been in negative anomalies and continuous reduction since 1980.