| 关于全球冷暖和亚,非夏季风区干湿变迁之联系的一个述评 |
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| 引用本文： | 严中伟 Maire,NP.关于全球冷暖和亚,非夏季风区干湿变迁之联系的一个述评[J].地理学报,1995,50(5):471-479. |
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| 作者姓名： | 严中伟 Maire NP |
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| 作者单位： | 中国科学院大气物理研究所 |
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| 基金项目： | 国家科委攀登85－27项目,中科院KY85－10项目 |
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| 摘 要： | 基于近年来的多种资料分析结果，讨论了不同时间尺度上全球热状况这于中国东部和其它低纬亚非夏季风影响区干湿变迁的宏观控制作用。指出：在丰年以上时间尺度上，全球暖而夏季风强从而导致有关区域多雨偏湿，全球冷则夏季风区域多偏干；但较短时间尺度上的全球性冷暖波动往往不足以使各地的夏季风系统和干湿状况产生一致响应。
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| 关 键 词： | 全球变化 区域干湿 季风 气候变化 |
ON THE RELATIONSHIP BETWEEN GLOBAL THERMAL VARIATIONS AND THE WET/DRY ALTERATIONS IN THE ASIAN AND AFRICAN MONSOON AREAS |
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| Yan Zhong Wei,Petit-Maire Nicole.ON THE RELATIONSHIP BETWEEN GLOBAL THERMAL VARIATIONS AND THE WET/DRY ALTERATIONS IN THE ASIAN AND AFRICAN MONSOON AREAS[J].Acta Geographica Sinica,1995,50(5):471-479. |
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| Authors: | Yan Zhong Wei Petit-Maire Nicole |
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| Abstract: | Based on the various data analyses, the paper aims to making a discussion of the impacts of the past global warm/cold variations on the humidity changesalong the low-latitudinal summer monsoon ranges in Asia and Africa. The ways the regional climates respond to global changes may be quite different at different time-scales.In fact, it is widely noted that at the time-scale longer than 102yr, the summer monsoons are generally stronger during global warmer periods, thus leading to wetter conditions in the presently semiarid and arid regions in Asia and Africa. Dry conditions prevail the most of the areas concerned during cold periods, accompanied by rapid accumulation of loess in north China, lower lake-levels in Qinhai-Tibetan Plateau. desert development in northwestern India, Arabian Peninsula and Sahara.Because the thermal sensibility is generally larger in continent than in ocean. the globally warmer (colder) condition at long time-scale almost always implies a larger (smaller) thermal contrast between continent and ocean in summer, which is nothing but an essential force of monoson. The hightropospheric Easterly Jet and the relevant atmospheric circulations were also proposed as important factors to explain the in-phase humidity variations along Asian and African monsoon ranges.The mentioned global-regional relationship become weaker with decreasing time-scales. At 101-102-year-scales. which receive serious attention at the present in the field of global change study.temperature fluctuations are relatively small but may be locally considerable. Therefore. the themally driven circulations such as monsoons in different areas may not identically change. In recent history some wet/dry alterations at century-scale along the monsoon zones were found to be accompanied with the mild /cold variations of the Little Ice Age, but few evidences indicated the same at decadescale.During the mordern observation period. it was found that the 1920's global warming was clearly accompanied with the enhanced monsoon rainfall along the Asian and African semi-arid regions and that the 1960s' cooling led the event drying tend-ency along the same zones. However. the case of the 1980s'/global warming prevent us from clearly defining the global-regional relationship at the medium-term climate scale. We need to not only carefully analyze the long historical evolutions, but also pay much attention to the large-scale geographical patterns of climate changes and their atmospheric circulation backgrounds. The latter remains nowadays a particularly weak link in studying the regional climate changes and their relationship with global change. |
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| Keywords: | global change regional wet/dry alternation summer monsoon |
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