中国沙尘天气的区域特征

利用筛选的1954－2000年中国338个站沙尘天气资料及相关气候资料，从沙尘天气区划方面着重分析研究了我国沙尘天气的区域特征。结果表明：1）我国沙尘天气多发区分别位于以民丰至和田为中心的南疆盆地和以民勤至吉兰泰为中心的河西地区。不同类型沙尘天气的空间分布范围不尽相同，其中沙尘暴主要发生在与北方沙漠及沙漠化土地相联系的极干旱、干旱和半干旱区内。扬沙和浮尘天气除了在沙尘暴发生区的绝大部分地区出现外，还向其它邻近地区扩展，如扬沙可向东北地区和东南的黄淮海平原及以南地区扩展；而浮尘天气则主要向东南方向扩展，可涉及整个黄淮海平原和长江中下游地区。相比之下，上风方向的中高纬地区，如北疆和东北北部地区，浮尘天气发生甚少。2）全国沙尘暴天气易发区可划分为北疆、南疆、河西、柴达木盆地、河套、东北和青藏等7个亚区。沙尘暴和浮尘在南疆区发生日数最多，而扬沙在河西区发生日数最多。

Regional Characteristics of Dust Events in China

The dust events in China have been studied using the data of dust storms, wind-blown sand and floating dust from 338 observation stations selected in China from 1954 to 2000. The results are as follows: (1) In China, there are two high frequent areas of dust events, one is located in the area centered around Minfeng and Hotan in the South Xinjiang Basin, the other is situated in the area centered around Minqin and Jilantai in the Hexi Region. (2) The affected areas of dust storms can be divided into seven sub-regions, that is, North Xinjiang Region, South Xinjiang Region, Hexi Region, Qaidam Basin Region, Hetao Region, Northeastern China Region and Qinghai-Xizang Region. The area of the most frequent occurrence of dust storms and floating-dust is in South Xinjiang Region, and of wind-blown sand in the Hexi Region. The annual occurrence days of wind-blown sand in four representative regions have been increasing since 1998, but that of floating dust does not evidently reveal this phenomenon.