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關(guān)鍵詞: 區(qū)域性極端低溫事件, 時空演變, 轉(zhuǎn)折, 頻次, 強(qiáng)度, regional extreme low temperature events, spatial/temporal variation, shift, frequency, intensity

Abstract: An objective identification technique was used to detect regional extreme low temperature event (RELTE) during 1960-2009, and the spatial distribution and temporal variation of the events were investigated. Results indicate that the probability distribution of the minimum temperature and the latitude of the geometrical center of RELTEs both obey the bimodal distribution. The center of RELTEs was mainly located in two latitude belts of nearly 30°N and 42°N. Before the middle 1980s, the south and north belts coexisted but the north belt weakened obviously since then. Besides, the annual accumulative values of the frequency, intensity and maximum covering area of RELTEs decreased overall during 1960-2009 and there was an obvious phase shift at the end of 1980s and the variation became flat after 1990s. These characters might result from the RELTEs with long duration and wide space range which accounted for 10% of all events. Further more, the integration index that reflects the overall influences of RELTEs were further investigated.