贵南县农业气象灾害演变特征研究

贵南主要农业气象灾害有霜冻、干旱、冰雹等。从1961—2012年资料统计分析得到贵南农业气象灾害演变特征为:春季终霜日为6月12日,秋季初霜日为8月20日;平均无霜期为68 d,无霜期总体上有延长的趋势。马铃薯和小油菜易受晚霜冻和早霜冻灾害。干旱主要发生在春、夏季节,总体看平均10年中5年有干旱,3年为轻旱,2年为中旱;最严重的干旱为2000年,春夏连旱;干旱总体为增加趋势,春旱为增加,夏旱为减少趋势。冰雹在1961—2012年共出现了252次,主要出现在3~10月,6月出现冰雹的次数最多,5月次之;最大冰雹的直径为30 mm;7月和8月出现在贵南的冰雹灾害强度最大;冰雹出现次数总体趋于减少,在年内冰雹出现的初日有提前的趋势。

A Study of Evolution Characteristics of Agricultural Meteorological Disasters in Guinan County

The main agricultural meteorological disasters in Guinan are drought, hail, frost, etc. The evolution characteristics of agricultural meteorological disasters in Guinan were obtained by an analysis of the statistical data from 1961 to 2012. The spring last frost day was on June 12 th and the fall first frost day was on August 20 th. The average frost-free period lasted for 68 days; the frost-free period in general had a tendency to extend. The potatoes and rapes were easy to get late frost and early frost disasters. The drought mainly happened in spring and summer. In general, there were five years droughts in every ten years, three years was the light drought and two years was the moderate drought. The worst drought happened in2000; it lasted from spring and summer. In general,the drought showed a trend of increasing. The spring drought was increasing and the summer drought was reducing. There were 252 hails happened from 1961 to 2012 and they mainly occurred from March to October. The hails happened most frequently in June and then in May. The maximum diameter of the largest hailstones was 30 mm,and the most serious hail disaster happened in July and August. The hail occurrence number tends to decrease and the first day of hail happened in a year showed a tendency to come earlier.