石家庄地区极端寒热和强降水的观测事实

利用石家庄地区17个观测站1972-2009年的气温和降水资料，选取8个极端气温指数和5个极端降水指数，分析气温和降水极端事件的变化规律。结果表明：近38 ａ，炎热日数呈增加趋势，寒冷日数、霜冻日数和结冰日数呈减少趋势，其中寒冷日数和霜冻日数呈显著减少趋势。中东部县市热指数的增加趋势和冷指数的减少趋势最明显。极端最高气温和极端最低气温呈弱的升高趋势；最高气温极小值和最低气温极大值则呈显著升高趋势。4个气温极值指数趋势变化的空间分布差异较大。大雨日数和暴雨日数均呈弱的增加趋势，各站的大雨日数和暴雨日数增加或减少的趋势不明显。1日和3日最大降水量均呈弱的上升趋势，但绝大部分站上升或下降的变化趋势不明显。强降水强度呈弱的增强趋势，暴雨强度的线性趋势为0.83 mm/（d·10 a）。大部分站大雨以上强度的增强或减弱趋势与暴雨强度一致。

Observed Change of Extreme Climatic Events in Shijiazhuang

In this paper,the changes of frequency and intensity of extreme temperature and precipitation events were analyzed using 8 extreme temperature indices and 5 extreme precipitation indices based on the daily temperature and precipitation data observed by 17 meteorological stations in Shijiazhuang during the period of 1972-2009.Results showed that warm days tended to increase,but cold days,frost days and ice days tended to decrease,especially there was a significant decrease of cold days and frost days.The increase of warm indices and the decrease of cold indices were the most significant at the stations in the eastern part of the study area.There was a slight increase of extreme maximum and minimum temperature,and also a significant increase trend of annual lowest values of maximum temperature and the highest values of minimum temperature.The spatial distribution of 4 extreme temperature indices was quite different,and there was a slight increase of heavy rain days and rainstorm days.There was also a slight increase of maximum 1-day and 3-day precipitation,but such trend was not significant at most stations.The linear trend of rainstorm intensity was only 0.83 mm/(d·10 a),and the increase or decrease trend of heavy rain intensity accorded with that of rainstorm at most stations.