摘要
本文利用1951—1980年的月平均温度,计算了中国各地水分需要量。根据水分需要量和降水量大小,将我国划分成潮湿、湿润、半湿润、半干燥和干燥5类气候区;并对这5个气候区1950年前后各30年时段的气候干湿状况进行讨论;此外还对影响气候干湿变化的重要因子,我国近30年来的降水进行了分析。 近3O多年来,各气候区的降水及气候状况呈现了不同的变化:潮湿和湿润气候区50年代降水较多,60年代降水偏少,70年代降水呈多变态;半湿润和半干燥气候区50年代至60年代中期为多雨时段,1965年始,降水偏少,处于少雨阶段,干旱发展;干燥气候区50年代初降水略偏多,50年代中期至70年代初降水偏少,从1973年至1984年,降水又略有增多。 另外,我国半湿润、半干燥气候区的降水趋势,多年来与非洲地区的降水有相似之处,特别是近20年来,都出现了降水持续偏少的现象,干旱发展,但我国半干燥、半湿润区的干旱程度还没像非洲干旱现象那么严重。
In this paper, the potential evapbtranspiration is calculated by using the Thornthwaite 's (1948) system and the moisture index is determined by comparison of it with the corresponding precipitation at 340 stations in China, based on the monthly mean temperature and precipitation data sets of the years 1951 - 1980.According to the analysis of the moisture indices, the climatic regions in China are classified into five types. The secular variations of the dryness and the wetness in each climatic region during the period of 1951 - 1984 are discussed.It is revealed that the trend of precipitation in North China was similar to that in the Sahel to some extent during the last 20 years, but the drought in North China was not as severe as that in the Sahel.
出处
《大气科学》
CSCD
北大核心
1991年第5期72-81,共10页
Chinese Journal of Atmospheric Sciences
关键词
气候
干燥
湿润
变化
Potential evapotranspiration
Moisture index
Relative variability
Interannual change.
