[Spatiotemporal evolution characteristics of late spring cold in Guizhou Province under global climate change]

Based on the 1959-2007 observation data of daily mean temperature from 19 meteorological stations in Guizhou Province, and combining with the late spring cold (LSC) intensity index and disaster grade division standard, this paper analyzed the spatiotemporal evolution characteristics of LSC, including LSC occurrence frequency, ratio of LSC-occurring stations to all stations, decadal variation, abrupt climate change, and periodic variation, in the province. In 1959-2007, the occurrence frequency of no LSC in the province was the highest, followed by serious LSC, and that of medium and slight LSC was approximately the same. Under the background of global warming, the ratio of medium LSC-occurring stations to all stations had the most obvious variation, with the climatic trend reached 1.4% x (10 a)(-1), while the ratios of no LSC-, slight LSC-, and serious LSC- occurring stations all showed an appreciably decreasing trend. The LSC intensity in the province was the highest in the 1990s, followed by in the 1980s, 1960s, 1970s, and 2000-2007. In the province, the LSC intensity showed an increasing trend in west and northwest high altitude areas, central area, and north area, but an appreciably decreasing trend in east and south areas. In the west, northwest, north, and central areas of the province, LSC intensity had a mutation from low to high in 1975. The LSC in the province had an obvious periodical variation, with the inter-annual period being mainly 2-4 years, and the decadal periods being mainly 13 - 15 years and 27-29 years.