The spatial distribution and monthly/annual variation of foggy days in China are analyzed based on the monthly mean fog data collected from 604 observational stations for the period 1961-2000. Results show that there ...The spatial distribution and monthly/annual variation of foggy days in China are analyzed based on the monthly mean fog data collected from 604 observational stations for the period 1961-2000. Results show that there are six fog regions in China： the middle reaches of the Yangtze River, coastal areas, Yunnan-Gulzhou Plateau, eastern Gansu-Shaanxi region, Huaihe River valley, Tianshan mountainous area and northern Xinjiang. On the whole the interannual variation trend of foggy days is descending, especially an obvious decline after the 1980s. The areas where the foggy days have obvious tendency present a southwest-northeast direction. The rising trend regions alternate with descending trend regions, forming a SE-NW directional wave structure. In general, the number of foggy days in autumn and winter is larger than in spring and summer over most fog regions. The monthly variation curves of foggy days are bimodal in the coastal area of the Yellow Sea and northern Xinjiang, and unimodal in other regions.展开更多
Using foggy days and mean temperature and relative humidity data of 602 stations from January to December in the period 1961-2003 in China, the relationship between variations of foggy days and temperature and its pos...Using foggy days and mean temperature and relative humidity data of 602 stations from January to December in the period 1961-2003 in China, the relationship between variations of foggy days and temperature and its possible reason for the 43 years were analyzed by regression, correlation and contrastive analysis methods. The results show that the higher （lower） the mean temperature and the lower （higher） the relative humidity correspond to less （more） foggy days, the relationship is the best in the western, northern and eastern Sichuan, Yunnan-Guizhon Plateau, and southeast highland in China. This induces a decrease in relative humidity when the climate becomes warmer, and eventually brings about a decrease in foggy days in China.展开更多
基金The key project of Ministry of Science and Technology of China, No.2003DEA2C009-02
文摘The spatial distribution and monthly/annual variation of foggy days in China are analyzed based on the monthly mean fog data collected from 604 observational stations for the period 1961-2000. Results show that there are six fog regions in China： the middle reaches of the Yangtze River, coastal areas, Yunnan-Gulzhou Plateau, eastern Gansu-Shaanxi region, Huaihe River valley, Tianshan mountainous area and northern Xinjiang. On the whole the interannual variation trend of foggy days is descending, especially an obvious decline after the 1980s. The areas where the foggy days have obvious tendency present a southwest-northeast direction. The rising trend regions alternate with descending trend regions, forming a SE-NW directional wave structure. In general, the number of foggy days in autumn and winter is larger than in spring and summer over most fog regions. The monthly variation curves of foggy days are bimodal in the coastal area of the Yellow Sea and northern Xinjiang, and unimodal in other regions.
基金The key project of the Ministry of Science and Technology of China, No.2004DKA20170-02
文摘Using foggy days and mean temperature and relative humidity data of 602 stations from January to December in the period 1961-2003 in China, the relationship between variations of foggy days and temperature and its possible reason for the 43 years were analyzed by regression, correlation and contrastive analysis methods. The results show that the higher （lower） the mean temperature and the lower （higher） the relative humidity correspond to less （more） foggy days, the relationship is the best in the western, northern and eastern Sichuan, Yunnan-Guizhon Plateau, and southeast highland in China. This induces a decrease in relative humidity when the climate becomes warmer, and eventually brings about a decrease in foggy days in China.
