1961-2016年中国冰雹日数时空演变特征

Temporal and spatial evolution characteristics of hail days from 1961 to 2016 in China

采用1961—2016年2 481站的冰雹日数数据,利用多种统计方法分析了中国及七大地理分区的冰雹日数时空分布特征和周期变化规律。结果表明:1961—2016年中国整体及其不同区域的冰雹日数整体均呈减少趋势,且西藏(东南)地区明显高(低)于其他6个分区和全国平均水平。全国和七大地理分区的年均冰雹日数在5年以下和30~60年尺度上的振荡周期相对显著,且大致都在1990s中期至2000s中期发生突变。中国冰雹事件多发区域比较稳定,且在分布上西部地区较多,东部地区较少;地表复杂地区较多,地表单一地区较少;高原和山地较多,平原较少;迎风坡较多,背风坡较少。2000s和2010s为全国冰雹日数偏多的年代,而1960s和1990s则偏少。1961—2016年全国年均冰雹日数呈增加趋势的地区分布较少,而呈减少趋势的地区主要集中在西藏、青海南部及东北部、四川西部、新疆西北部、内蒙古中部及其交界的河北北部、内蒙古东北部、黑龙江中部和吉林东部地区。全国年均冰雹日数波动特征从东南沿海向西北内陆呈现"两端高、中间低"的分布特征。波动较大的地区主要分布在华东、华南、华中、重庆、四川东部、陕西南部、内蒙古西部、新疆东部及其交界的甘肃地区、新疆南部及其交界西藏地区。

In accordance with the data of hail days from 2 481 stations,the temporal and spatial distribution characteristics and periodic variation law of the hail days in China and within its seven geographical regions are analyzed herein with several statisti-cal methods.The result shows that the hail days from 1962-2016 all over China and within its various regions integratedly present decreasing trends,for which the region of Tibet(the southeast)is obviously higher(lower)than those of the other six re-gions and the national average.The oscillation cycles of the annual average hail days all over China and within the seven geo-graphical regions on the scales less than five years and 30~60 years are relatively significant,and that the mutations of hail days occur in most of them from the mid-1990s to the mid-2000s.The hail days in those hail-prone areas in China are relatively sta-ble,which is more within the western region and less within the eastern region,more within the region with complicated surface and less within the region with single surface,more within the plateau and mountainous region and less within plain region,more within the region with windward slope and less within the region with leeward slope in the aspect of the distribution.Moreover,2000s and 2010s are the decades with more hail days in China,while 1960s and 1990s are the decades with less hail days.Dur-ing 1961-2016,the regions with the increasing trend of hail days are less distributed in China,while the regions with the de-creasing trend are mainly concentrated in the areas of Tibet,the South and Northeast Hainan,the West Sichuan,the Northwest Xinjiang,the Mid-Inner Mongolia and its adjacent the North Hebei,the Northeast Inner Mongolia,the Mid-Heilongjiang and the East Jilin.The fluctuation of the annual average hail days in China presents the distributioncharacteristics of“higher on both the ends and lower in the middle”from the Southeast Coast to the Northwest Inland.The regions with larger fluctuation are mainly distributed in the areas of the East China,the South China,the Central-China,Chongqing,the East Sichuan,the South Shaanxi,the West Inner Mongolia,the East Xinjiang and its adjacent region of Gansu,the South Xinjiang and its adjacent region of Tibet.