汤晨阳 徐相明 顾品强

摘 要：该文利用奉贤区气象站1960—2015年日照时数及降水日数资料，分析奉贤区近56a日照时数变化特征。结果表明：近56a奉贤地区年平均日照时数为1 945.3h，异常年份9a，月日照时数呈现“一高峰两低谷”的规律，年、季度日照时数气候变化趋势呈现为一元二次方程，四季占年日照时数的比例值除春季外均呈现下降趋势，且21世纪以来各季占年日照时数均近1/4，如2011年、2014年、2015年；20世纪80年代以来年日照处于资源丰富、年际变化比较平稳的状态，尤其是1月、10月、11月日照时数变化较为稳定，但8月是日照资源丰富但变化幅度大的月份。通过相关分析得到日照时数的变化与降水日数呈负相关关系，年降水日数每增加1d，年日照时数减少7.4h，且当降水日数≤135d时日照时数一般≥1 800h、降水日数>135d时日照时数一般≤2 000h。

关键词：日照时数；变化特征；降水日数

中图分类号 P468 文献标识码 A 文章编号 1007-7731（2016）14-0149-04

Abstract：Using the data of sunshine duration and precipitation days at Fengxian meteorological station from 1960 to 2015，the variation characteristics of sunshine duration in the past 56 years have been analyzed. The result indicates that，the annual average sunshine hours at Fengxian area in recent 56 years is 1945.3 hours.There are nine abnormal years. The monthly sunshine duration has shown a significant tendency of a peak two valleys. The trend variation of the annual and seasonal sunshine duration appears as a quadratic equation. The seasonal sunshine duration accounted for the proportion of the annual sunshine duration present obvious down treng except spring. The seasonal sunshine duration is accounted almost for a quarter of the annual sunshine duration since the 21st century，such as 2011，2014，2015. Since the 1980s，the annual sunshine duration is rich in resources and its interannual variability presents relatively stable state，especially as in January，October，November.But in August，there are large variations of sunshine hours. Through some relative analysis，the variation of sunshine duration is obviously negatively with precipitation days. When annual precipitation days increase 1d per year，annual sunshine hours reduce 7.4h. When annual precipitation days are≤135d，annual sunshine hours are≥1800h generally. When annual precipitation days are>135d ，annual sunshine hours are≤2000h generally.

Key words：Sunshine duration；Variation characteristics；Rainy days

在日常生产中，气候因子对作物物候影响明显，光照条件是重要因子之一，目前已有众多学者进行了光照对物候的影响分析，如宫恒瑞等[1]对乌昌地区近30a日照时数进行了分析，得出日照时数的变化对设施农业生产的不利影响较为明显；曹巧莲等[2]得出临汾市日照时数的减少对小麦、玉米、棉花的生长都有不利影响；李君海等[3]得出陵水县日照时数变化对农业的影响以冬季最为突出。

上海奉贤位于长三角，处于杭州湾北岸，属于亚热带季风气候。作为上海农业大区（县），农业生产一直受到市委市政府的高度重视。为更……