近50年陕西省无霜期的变化及果区霜冻风险分布

利用陕西省96个气象台站1961～2010年的日最低气温资料,计算了陕西各站历年霜冻的初日、终日及无霜期,并对其分布特征及年际变化进行分析。结果显示,陕西省初霜日、终霜日、无霜期等值线在陕北大致呈经向分布,在关中和陕南大致呈纬向分布;50年间,全省96站初霜日最早和最晚平均值相差44天,终霜日最早和最晚平均值相差49天,无霜期最长和最短天数平均值相差68天;全省平均初霜日呈推迟趋势,推迟幅度约为1.4天/10年;平均终霜日呈提前趋势,提前幅度约为1.7天/10年;平均无霜期呈加长趋势,加长幅度约为3.1天/10年。最后依据风险分析理论对陕西多个苹果基地县进行了花期霜冻风险分析,得出其风险的空间分布特点,结论对精确指导和开展防灾减灾工作有参考作用。

The changes of the frost-free periods from 1961 to 2010 and its impact on apple industry in Shaanxi province

Using the Daily minimum temperature data from 1961 to 2010 of 96 weather stations in Shaanxi province,we calculated the first frost dates,last frost dates and frost-free periods of 96 weather stations from 1961 to 2010,and analyzed its distribution characteristics and inter-annual changes.The results showed that the contours of the first frost dates,last frost dates and frost-free periods was shown latitude distribution in Northern Shaanxi and showed latitude distribution in Guanzhong area and southern Shaanxi.During the 50 years,the difference of average earliest and latest first frost date of 96 weather stations was 44 days;the difference of average earliest and latest last frost date of 96 weather stations was 49 days;the difference of average longest and shortest frost-free periods of 96 weather stations was 68 days;the average first frost date of 96 weather stations showed postponed trend and about postponed 1.4 days every 10 years;the average last frost date showed advanced trend and about advanced 1.7 days every 10 years;the average frost-free periods showed increased trend and about increased 3.1 days every 10 years.Finally we analyzed the apple frost damage risk of some apple's base counties of Shaanxi according to the theory of risk analysis and got its spatial distribution feature.The conclusion has a reference on guiding and launching disaster prevention and reduction work accurately.