科研之友
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摘要
Rainy seasons in China are defined quantitatively and their characters are discussed in details by virtue of the daily rainfall data at 740 stations in China from 1951 to 2004, complied by China Meteorological Administration (CMA). It is found that the major rainy seasons begin earliest in central South China and latest in the Huaxi region, including Sichuan province, Southern Gansu province and Southern Shanxi province. Major rainy seasons in China persist for 20 to 70 days, with the rainfall amounts accounting for 30 to 60% of the annual rainfalls, depending on different regions. In East China, the major rainy season of monsoonal nature advances from south to north, whereas in West China, the major rainy season commences earlier in northwestern part than that in the southern part, with obvious local features. In most areas of China, including North and Northeast China, Northwest China and the Tibetan Plateau, rainfalls highly concentrate in mid-summer and show the single peak mode. However, rainfalls show the dual peak mode both in South China and Huaxi region and the triple peak mode in the middle and lower reaches of the Yangtze River. These rainfall peak modes are to a great extent related to the climatic intra-seasonal oscillation (CISO). The obvious climatic intraseasonal oscillation in rainfalls with the 30-60-day mode predominates in the middle and lower reaches of the Yangtze River, while the 10-30-day mode is mainly observed in South China as well as in North China. Further analysis shows that the CISO also modulates significantly the active-break cycle of regional rainy seasons in East China. Six significant regional rainy seasons are identified in China from spring to autumn, including the spring rainy season to the south of the Yangtze River, the pre-summer season in South China, the Meiyu in the Yangtze and Huaihe valley, the rainy season in North and Northeast China, the second or post-flooding season in South China and the autumn rainy season in areas of Huaxi region. These rainy seasons are mainly controlled by the East Asian summer monsoonal systems, together with the impact from mid- and high latitudes, especially in the spring and the autumn rainy season. Finally, the related water vapor transport and budgets for the regional rainy seasons is estimated and discussed.
- 出版日期2008-8
- 单位国家气候中心
