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1.
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 总被引:4,自引:0,他引:4
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。 相似文献
2.
THE DEPENDENCE OF THE ANNUAL TOTAL ON THE NUMBER OF RAIN‐SPELLS AND THEIR YIELD IN THE MEDITERRANEAN
Rain‐spells are a key parameter for examining the variation in rainfall amounts, especially in arid and semi‐arid areas. A rain‐spell is defined as a period of consecutive days with rainfall above a certain determined Daily Rainfall Threshold (DRT). Two different seasons or two stations may have the same average TOTAL, but different synoptic conditions are the cause for the differences in their Number of Rain‐Spells (NRS) their Rain‐Spells Yield (RSY) or both. The present study examines whether a season is drier/wetter according to its length, or whether it depends on the NRS in 41 Mediterranean stations. It analyses the relationships between dry/wet seasons and various elements of the rain‐spells. These objectives are analysed both at a basin level of the entire Mediterranean, and at a station level. The main conclusions at the basin level are that precipitation amounts are not related to the length of the seasons, and therefore, a Short or a Long season can be either Dry or Wet. The significant positive correlation between the TOTAL and the annual NRS that was found indicates that a Dry season tends to have Few rain‐spells and a Wet season tends to have Many rain‐spells. At the station level of most stations, a Dry or Wet season is caused mainly by changes in the RSY and less so by changes in the NRS. This tendency is more evident in the southern Mediterranean. Furthermore, Wet seasons are characterized by an increase in the number of Long rain‐spells (longer than three days) and mainly in the RSY of these spells. These conclusions may serve to characterize the rainfall regime under any scenario due to a climatic change. 相似文献
3.
新疆天山山地自然灾害垂直带谱及其特征 总被引:3,自引:1,他引:3
分析天山山地由气候原因引起的自然灾害分布的垂直带谱,主要灾害类型有12种,可分为3个带:(1)基带(暴雨-塌方带):主要是由中、低山突发性的降雨引起的各种灾害。此带灾害频发时期与最大降水期是同步的。(2)中带(融水-冰冻带):其灾害大多同温度的变化有密切的关系。(3)上带(风吹雪-雪崩带):由积雪运动造成的灾害多集中在这里。山地坡向和高度对自然灾害垂直带谱的组成和灾害出现的频率影响很大。由于温度和 相似文献