近50年莆田市区阴天日数的时空特征

Temporal and Spatial Variations of Count of Overcast-Sky in Putian in Recent 50 Years

本文应用1961-2012年莆田、仙游2站地面气象水汽压、云量及日照的月、年等观测资料分析了莆田市阴天日数的时空分布特征,结果表明:1961-2012年莆田市的地面水汽压、阴天日数及年日照时数有明显的年际和年代际变化;莆田市区1981年以后水汽压减少呈减小趋势,干岛效应主要由夏季变干引起的,仙游城关的水汽压变化不明显;阴天日数变化趋势各地区不一致,莆田站1984年以后呈增多趋势,仙游城关略呈下降趋势;年日照总时数总体上经历了"多日照-少日照-多日照"三个年代,但城镇化步伐较快的莆田城区由第一阶段、第二阶段转变的时间较早,本世纪以来莆田城区及仙游年日照时数均出现回升现象。

The temporal and spatial variations of overcast-sky in Putian were analyzed by using yearly and monthly data of water vapor press, sunshine hours, cloud fraction, etc. from 2 meteorological stations such as Putian and Xianyou from 1961 to 2012. The results showed that the water vapor press, the count of overcast-sky and the sunshine hours varies annually in recent 50 years. Because of the dryness in summer, the water vapor press decreased in city center whereas remaining steady in Xianyou. The trend of count of overcast-sky is different between Putian and Xianyou. It showed obvious increasing trend in city center since 1984 but a little decreasing trend in Xianyou. The total sunshine hours experienced three periods as rich-sunshine, poor -sunshine and rich sunshine, respectively. The convert year from phase-I to phase-II was earlier in city center due to the urbanization and industrialization. In both Putian and Xianyou, the sunshine hours increased again since the new century.