关键词: 初霜冻日, 偏早初霜冻, 特早初霜冻, 中度初霜冻, 重度初霜冻

Abstract: Based on first frost date and daily minimum ground temperature data at 62 meteorological stations in Shanxi province from 1961 to 2010,authors analyzed the temporal and spatial distribution and abrupt change by using EOF (Empirical Orthogonal Function) and M-K abrupt change method.The results showed that spatial distribution of first frost dates occurred from second ten days of September in north to first ten days of November in south with 5 steps.Probability of normal first frost in Shanxi province was 62% to 82%,and had a distribution trend of “large-small-large”from north to south Probability of earlier first frost in Shanxi province was 6% to 26%,and had a distribution trend of“small-large-small”from north to south.The earliest first frost occurred in west and middle-east of Shanxi province,with the probability of 4% to 22%.Occurrence times of first frost,mild first frost,moderate first frost and severe first frost showed same “more”or“less”in most years.It was found with M-K abrupt change test that first frost date of most stations had abrupt change,which concentrated in eighth and ninth decades in last century;north and south region were earlier than middle region.

Key words: First frost date, Earlier first frost, Earliest first frost, Moderate first frost, Severe first frost