近50a中国霜期的变化特征分析

Climatic change of frost in China in recent 50 a

通过对中国霜气象观测资料的整理和分析,研究了1957—2006年中国霜期、初霜日、终霜日的时空分布和气候特征。结果表明,中国各地的霜期总体上是自北向南、自高山向平原逐渐缩短的,霜期长(短)的地区与初霜早(晚)、终霜晚(早)的地区非常一致。近50 a来,在全球增暖的背景下,中国大部分地区霜期在逐渐缩短,初霜日在逐渐推迟,终霜日在不断提前,1990s后这种趋势变得更加明显。霜期缩短显著的区域主要集中在我国东北、华北、内蒙古中部、江淮流域以及云贵高原和华南部分地区,而四川盆地和长江中下游部分地区霜期缩短的趋势并不明显,一些地方甚至略有延长的趋势。比较初霜日期与终霜日期的趋势变化,发现终霜日提前的趋势要比初霜日推后的趋势更加明显,这可能是由不同季节的增温幅度不同而引起的。

Based on daily meteorological observational data of frost in China, the spatiotemporal distribution of frost has been investigated from 1957 to 2006. The climatic change of frost season, the first and last dates of frost are mainly analyzed. The results show that the frost seasonal length is longer in the north and on the mountain than in the south and on the plain in China as a whole. The longer frost season is always consistent with the earlier first frost day and the later last frost day, vice versa. In the background of global warming in the last 50 years, the frost seasonal length shortened, the first dates of frost occurred later and the last dates of frost occurred earlier, especially after 1990＇s. The notable trend is evident in Northeast China, North China, Middle Inner Mongolian, Yangtze-Huaihe region as well as Yunnan-Guizhou Plateau and some part of South China, while no obvious trend is found in Sichuan Basin and the mid-lower Yangtze River Basin, even a slightly reverse trend is showed in those places. Comparing with the trend of the first frost date and the last frost date, the latter appears to have a marked change than the former, which may have a very close relationship with the different variation of seasonal temperature.