摘要
分析了1920—2000年全球陆地降水场。指出降水量最大的区域主要在季风区,在季风降水区有明显的雨季和旱季之分。全球多年平均降水随纬向分布有着较好的连贯性,即热带地区比较湿润,从赤道向南向北递减,但是在南半球40°～50°S中高纬度降水量还比较多,故南半球降水随纬度分布呈双峰型。文中还分析了全球陆地平均的全年、各季降水序列的周期和趋势特征。指出全球降水序列中有明显的与2～7年ENSO周期相吻合的变化周期,也有年代际变化。在1920—2000年期间,除了冬季降水有一个弱的上升趋势外,其它季节降水量的变化趋势不很明显。分析比较了全球陆地年、各季降水长期趋势的地理分布差异,指出在南半球,赤道～10°S除了在春季降水表现为弱的负趋势外,其他季节都是正趋势,其中冬季最明显,但是并不显著。10°～25°S在冬、秋季是正趋势而夏季是负趋势,趋势都不显著。在20°～40°S夏、秋季的降水量正趋势达到0.01显著性水平。在北半球,25°N以南的热带地区的四季降水都是负趋势,在秋季尤为明显,达到0.01显著性水平。在30°N以北,除了在30°～40°N冬季表现为降水的负趋势外,其它季节降水为正趋势。在45°～55°N地区,降水的正趋势在春季表现的最为明显,在北半球更高的纬度上,冬季降水的正趋势表现的特别明显。
Analyses of global land precipitation data fields from 1920 to 2000 show that the largest rainfall occurred in the monsoon areas where it exists clear rainy and dry seasons. The latitudinal distribution of global land mean annual rainfall showed continuity, i.e. climate in the tropics was wet, and rainfall was reduced northwards and southwards from the equator respectively. However, rainfall in the southern mid-high latitudes of 40°～50°S was relatively larger, thus precipitation in the Southern Hemisphere displayed a latitudinal distribution of double peaks. Period and trend analyses of annual and seasonal average precipitation series over global land show that the global land precipitation series showed obvious 2～7 years and interdecadal variations. During 1920_2000, except precipitation in winter exhibited a weak positive trend, it showed no clear trend in the other seasons. The long term trend of annual and seasonal precipitation over global land and its geographic distribution were also analyzed and compared with each over in this paper, and it is pointed out that precipitation in 0°～10°S of the Southern Hemisphere showed a weak negative trend in spring, and a positive one in the other seasons. The positive trend in winter was obvious but not significant. Precipitation in the zone 10°～25°S displayed a positive trend in winter and autumn, and a negative one in summer, and those trends all were not significant yet. In the zone 20°～40°S, the positive trends of summer/autumn precipitation were significant at 0.01 level. In the Northern Hemisphere, the tropical area to the south of 25°N, precipitation showed a negative trend in all seasons, and especially the negative trend of autumn was significant at 0.01 level. In the area to the north of 30°N, except the precipitation trend in the zone 30°～40°N was negative in winter, those in other seasons all were positive. In the zone 45° ～55°N, the positive trend of precipitation was most obvious in spring, and in the further north area, the pos
出处
《高原气象》
CSCD
北大核心
2004年第4期435-443,共9页
Plateau Meteorology
基金
国家自然科学基金项目(40275028
40275031)
南京气象学院气象灾害和环境重点实验室(KJS0302)共同资助
关键词
全球陆地
降水量场
气候变化
Global land
Precipitation fields
Climatic changes
