近30a我国5级以上风日数的时空变化特征

Spatial and Temporal Variations in Windy Days over Category 5 in China During 1975-2005

利用全国397个测站逐日最大风速资料,分析了1975—2005年我国5级以上风日数的气候平均特征和长期变化趋势。研究表明:5级以上风主要出现在我国北方地区,受地形和海陆分布影响,南方局部地区5级以上风日数也较多。就季节分布而言,春季最多,夏季次之,秋季最少。5级风日数的比例在我国南方地区大于北方,6级以上风日数比例则呈现北多南少的分布特征。近30a我国5级以上风日数呈线性减少趋势,春季风日数的减少趋势较其他季节明显,其中5级风日数的变化趋势较其他级风日数更为显著。

Based on the daily maximum wind speed （10-minute mean） data of 397 stations in China, the climatological characters and the linear trends of windy days over category 5 were analyzed during 1975-2005. The results show that winds over category 5 occurred in most of northern China and in some local areas and the narrow coastal zone of southern China. The windy days were the most in spring, the next in summer, and the least in autumn. The ratio of annual windy days for category 5 to the total number of windy days ovcr category 5 was greater in southern China than in northern China, but the opposite was true for the ratio of category 6. The windy days over category 5 generally showed linear decreasing trends during the past 30 years, and the decreasing trend was more remarkable in spring than in other seasons. The linear deceasing trend for category 5 was more distinctive than that for the other categories.