大别山北坡典型区域降水年内分配不均匀性特征研究——以安徽省六安市为例

研究大别山北坡降水年内分配时空特点，对指导区域内科学防灾减灾及水资源管理、调配具有重要的现实意义。利用六安市6个气象站1956~2010年逐日降水资料，基于降水集中度和集中期，探讨近55 a来六安市年降水集中程度的时空特征。结果表明:六安市年降水集中度变化于012~057，多年平均值037，多年平均降水集中期在37~38候。年降水量空间分布由西南向东北减少，集中度呈由南向北递增，集中期由南向北推迟。年降水总量无明显趋势变化，但集中度和汛期降水量的增加趋势显著，汛期发生洪涝灾害的风险加大。年降水量分别在1972、1990年发生一次增多和减少突变，集中度序列在1970年发生了增多突变。年降水量与集中度呈全区一致的正相关，即年降水量越大，降水越集中，相关系数分布由西南山地区向东北岗地圩畈区增加。对降水集中度与汛期旱涝的分析说明，汛期降水异常偏多，集中度偏大，易发洪涝灾害，反之易发旱灾

INTRA-ANNUAL INHOMOGENEITY CHARACTERISTICS OF PRECIPITATION IN LU’AN CITY ON THE NORTH SLOPE OF THE DABIE MOUNTAIN

Analysis on the distribution characteristics of precipitation in a year is of great importance for taking precautions against and fighting natural adversities as well as water resources management on the north slope of the Dabie Mountain.Using the daily precipitation data of 6 meteorological stations in Lu’an city from 1956 to 2010,the spatial and temporal distribution characteristics of annual precipitation concentration were analyzed based on the definitions of Precipitation Concentration Degree(PCD) and Precipitation Concentration Period(PCP).The results showed that the average PCD in Lu’an was 0.37 and the average PCP was the 37~38 pentad.The annual precipitation decreased gradually from southwest to northeast in spatial distribution,while the PCD and the PCP increased from south to north.The trend of annual precipitation was not obvious,but PCD and rainy season precipitation exhibited increasing tendency at the 0.10 significance level.It could lead to increasing risk of floods in rainy season in Lu’an city.The jumps in the annual precipitation occurred in 1972,1990 and an abrupt change occurred in 1972 in the PCD process.It is found that the annual amount of precipitation has significant positive correlation with PCD,that is to say the much(less) is the annual precipitation,the bigger(smaller) is the PCD.It is also found that when rainy season precipitation is extremely excessive and the PCD is much bigger than the average,Lu’an city is vulnerable to flood,otherwise to drought.