近56年京津冀区域降水量变化特征分析

Analysis on the Change Characteristics of Precipitation in Beijing-Tianjin-Hebei Region in Recent 56 Years

按照自然地理条件和气候的地理分布特征把京津冀分为5个不同的气候子区域,选取资料序列完整且具有较长时间序列较为均匀分布的87个地面气象站,运用线性回归、Mann-Kendall突变检验、滑动t检验、Morlet小波函数等统计方法,选用1960—2015年逐日降水观测数据,分别对5个子区域及全区的降水量进行时空变化特征分析。结果表明,近56年来京津冀全区及5个分气候区年平均降水量变化呈现整体的一致性,均呈波动下降趋势,冀东平原区下降趋势显著,但均未发生明显突变现象;存在较为显著的季节性,全区夏季降水量下降趋势显著,并于1996年发生突变,总降水量中以7月和8月贡献最大,降水量减少速率也最快;除太行山区外,其他分气候区夏季降水量均呈减少趋势,且冀东平原区减少幅度最大,燕山丘陵在1996年发生了明显突变;全区及各分气候区年、季降水量呈现显著的年际和年代或多年代际变化,主要存在4个周期变化,大致分为3～4、6～10、12～18和20年以上。

Beijing,Tianjin and Hebei were divided into five different climatic sub-regions according to their natural geographical conditions and climatic geographical distribution characteristics.87 meteorological stations with complete data series and relatively long time series were selected,and linear regression,Mann-Kendall mutation test,sliding t test and Morlet wavelet function were used.Statistical method was used to analyze the temporal and spatial variation characteristics of precipitation in five sub-regions and the whole region,using daily precipitation data from 1960 to 2015.The results showed that in the past 56 years,the annual average precipitation of Beijing-Tianjin-Hebei region and its five sub-climatic zones had shown a whole consistency,both showing a downward trend of fluctuations,and the downward trend in the eastern Hebei plain region was significant,but there was no obvious mutation;there was a more significant seasonal,the downward trend of summer precipitation in the region was obvious.Besides the Taihang Mountains,the summer precipitation in other climatic regions showed a decreasing trend,and the eastern Hebei Plain had the largest reduction range,and the Yanshan Hills had a significant abrupt change in 1996.All the climatic regions and sub-climatic regions had the fastest reduction rate.The annual and seasonal precipitation showed significant interannual and interdecadal or interdecadal variations.There were four main periodic variations,which were roughly divided into 3-4 years,6-10 years,12-18 years and more than 20 years.