近48 a巴彦淖尔地区日照时数变化特征及影响因子分析

Analysis on variation of sunshine duration and its influencing factors in Bayannur Region in recent 48 years

基于巴彦淖尔地区8个国家气象观测站1975—2022年日照时数逐月整编资料,采用气候倾向率、显著性检验、滑动t检验以及相关性分析等方法,对该地区日照时数的变化特征以及对日照时数有影响的多个气象因子进行统计分析。结果表明:巴彦淖尔地区近48 a日照时数呈显著下降趋势,气候倾向率为-21.78 h/10 a,并在1981年和1985年发生了两次突变现象。四季日照时数均呈现不同程度的下降趋势且下降强度不一,其中秋季减少强度最大,为-9.52 h/10 a;冬季减少强度最小,为-1.53 h/10 a。四季平均日照时数由多到少依次为夏季>春季>秋季>冬季,四季日照时数异常(或接近异常)偏少情况主要发生在1992年以后,异常(或接近异常)偏多情况主要发生在1978—1990年之间。各月平均日照时数分布不均匀,最大值出现在5月,最小值出现在12月,其中6月和9月对巴彦淖尔地区日照时数的减少贡献率最大。年日照时数与平均气温、平均水汽压、霾日数、雾日数呈负相关,与大风日数呈正相关;秋季日照时数的减少主要受雾日数增多的影响,其次是受水汽压增大、霾日数增多和大风日数减少的影响;夏季和春季日照时数的减少主要受水汽压增大的影响。

Based on the monthly sunshine hours data of 8 national meteorological observation stations in the Bayannur region from 1975 to 2022,the variation characteristics and influencing factors of sunshine hours were analyzed using methods such as climate tendency,significance test,sliding t-test and Pearson correlation analysis.The results show that there is an obviously decrease of sunshine duration in Bayannur region in recent 48 years,with a climate tendency rate of-21.78 h/10 a,and two mutations occurred in 1981 and 1985.Sunshine duration showed varying degrees of downward trend in all seasons.The maximum reduction intensity in autumn is-9.52 h/10 a.The minimum reduction intensity in winter is-1.53 h/10 a.The average sunshine duration are in summer,spring,autumn,and winter from highest to lowest.Anomalously higher seasonal sunshine duration were mainly observed from 1978 to 1990,while anomalously lower seasonal sunshine duration mainly occurred after 1992.Among the monthly sunshine duration,the maximum value appears in May and the minimum value appears in December,with June and September having the greatest contribution to the reduction of sunshine duration in the Bayannur region.The annual sunshine duration are negatively correlated with average temperature,average water vapor pressure,haze days,and fog days,but positively correlated with strong wind days.The decrease in autumn sunshine duration is mainly affected by the increase in fog days,followed by the increase in water vapor pressure and haze days,and the decrease in strong wind days.The decrease in sunshine duration in summer and spring is mainly affected by the increase in water vapor pressure.