鲁西南近50年降水量和雨日雨强变化趋势

PRECIPITATION IN SOUTHWEST SHANDONG IN RECENT 50 YEARS AND THE VARIATION TREND OF RAINY DAYS AND RAININESS

关键词:  鲁西南　降水量　雨日　雨强　50年变化趋势

Key words:  the southwest of Shandong  precipitation  rainy days  rainy intensity  variation trend

摘要:

利用最小二乘法、Mann-Kedall方法分析近50年来鲁西南9县区降水量、雨日、雨强变化。结果表明:鲁西南中南部地区降水日数减少较北部明显;≥25.0mm、≥50.0mm、≥150.0mm平均降水日数均呈略增加趋势,≥100.0mm降水日数中北部呈减少趋势,南部呈增加趋势。各级平均降水日数均与年平均降水量显著相关,≥25.0mm降水日数与年降水量相关最为密切,说明从平均状况看,降水量的多少取决于降水日数的多少,特别是≥25.0mm降水日数的多少。平均最长连续降水和无降水日数均呈减少趋势。平均最大连续降水量以3.719mm/10年的趋势减少 (近30年以6.724mm/10年的趋势增加),平均最大日降水量以0.38mm/10年的趋势略增 (近30年以4.904mm/10年的趋势增加)。平均1小时最大降水量以1.423mm/10年的趋势增加,平均10分钟最大降水量以 0.707mm/10年的趋势增加。鲁西南年平均降水资源减少,年降水季节和空间分布明显,气候有"干化"变化趋势。降水日数减少但降水强度增加,短时强降水出现的月份集中且夜间出现频率接近50%,致使洪涝灾害防御任务更加艰巨,应做好气象灾害防御规划趋利避害。

Abstract:

Using the least square and Mann-Kendall method,this paper analyzed the characteristic of climate variation of precipitation,rainy days and rainy intensity in the southwest of Shandong province in recent 50 years.The results showed that:the rainy days decreased in central and southern were more than that in northern Shandong province;the days with average precipitation≥25.0mm, ≥50.0mm, ≥ 150.0mm showed a slightly increasing trend,but the number of days with precipitation ≥100.0mm tended to decrease in North and increase in the South.The average number of days with precipitation levels were significantly correlated with mean annual precipitation,precipitation days with precipitation≥ 25.0mm significantly correlated with annual precipitation.The average longest continuous rainfall and non-rainfall days decreased.The average maximum continuous precipitation decreased to 3.719 mm/10a trend,the average maximum daily precipitation amounted to an increase of 0.38mm/10a.An average of 1 hour's maximum precipitation increased to 1.423mm/10a,and an average of 10 minutes maximum precipitation increased to 0.707mm/10a.The average annual precipitation decreased which showed the climate was in a drier trend.The total precipitation days reduced but precipitation intensity increased,short-term strong precipitation happened in concentrated months and mostly in night,which resulted in more difficult in disaster prevention.The planning of meteorological protection should draw on the advantages and avoid disadvantages.