中国近80年来气候变化特征及其形成机制
CHARACTERISTICS OF THE CLIMATE CHANGE AND ITS FORMATION MECHANISM IN CHINA IN LAST 80 YEARS
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摘要: 自20世纪20年代以来,中国地区40和90年代出现了2个暖期及50~60年代相对冷期。最近的90年代的最暖年(1998年)或5a滑动平均气温几乎已达或略高于40年代的最暖年(1946年)或5a滑动平均气温。变暖最明显是北方地区(黑龙江和新疆北部),而35°N以南和100°E以东地区自50年代以来存在一个以四川盆地为中心的变冷带,虽然90年代有变暖趋势,但基本达到40年代暖期气温。中国降水则以20年代为最少(1929年最少),50年代为多水年代,以后缓慢减少,70年代以后变化不大,但多雨带在80年代及以后由华北南移到长江中下游。1951~1990年,大部分地区气温和降水呈负相关,在东北和长江—黄河间存在2个负相关中心,表明北方是变暖变旱,江淮间是变冷变湿。这些气候变化特征和全球气候变化相比较,除北方外,变暖期明显的滞后于全球变暖,并且出现变冷带等明显差异。文中还综述了用诊断和数值模拟方法对影响中国变化的气候自然变化和人类活动影响(热岛效应和气溶胶影响)的研究结果。我们认为,以上提出的3种人类活动对中国气候变化有明显影响,特别是工农业发展造成的气溶胶增加是四川盆地气温变冷的主要原因。Abstract: In this paper, some results concerning the study on the characteristics of the climate change and its possible formation mechanism in China for the apparatus observatory period since 1920s has been synthetically described in detail.Since 1920s, China experienced two warm-periods during 1940s and 1990s respectively and a relative cold period during the period of 1950s-1960s. During 1990s, the yearly mean temperature of the warmest year (1998) or the temperature of the 5-year running mean almost reached to or was warmer than that in 1946 which was the warmest year and that of the 5-year running mean during the previous warm period. The strongest warming areas were located in the northern China such as Heilongjiang province and northern Xinjiang autonomous region, while over the area south of 35°N; and east to 100°E, there existed acooling belt centered over the Sichuan Basin since 1950s. Although the area showed a warming trend during 1990s, it did not reach to the temperature during warm period of 1940s. In terms of the rainf all over China, it reached to the least during 1920s (least in 1929) while the most during 1950s and gradually decreased from then on. After 1970s, the rain fall amount had little change with weak oscillation but the pluvian region moved southward from North China to the middle and lower reaches of Yangtze river since 1980s. During the period of 1951-1990, the temperature and rainfall showed negative correlation over the most areas. There existed two negative correlation areas over the Northeast China and the region between the Yangtze river and Yellow river basin, which indicate that it turns warmer and drier over north area while more cold and wet over area between Huai river and Yangtze river. Comparing these characteristics of the climate change over China with that of the global scale, the warming period over China distinctly laged behind that of the global warming, and clear difference existed for the cooling belts.