中国北方典型沙尘天气特征研究

Characteristics of Dust Storm Weather in Northern China

根据API、风速、风向及相关气象数据初步研究了中国北方两次典型沙尘天气的天气特征。两次沙尘天气过程中极大风速大于7.2m.s-1的气象站占88%。2005年4月27日极大风速超过17.2m.s-1的气象站有31个,出现频率最高的风向为西西北,28日达到81个,风向为北风,极大风速高值区由内蒙古中东部向东北方向迅速扩大。2007年3月30日极大风速超过17.2m.s-1的气象站有57个,31日达到68个,风向均为西西北,极大风速高值区分布较为稳定。受沙尘暴影响的地区API显著升高。2005年4月28日呼和浩特、大同、北京3个城市的API分别为418、500、500。2007年3月31日呼和浩特、赤峰、大同3个城市的API分别为500、500、423。对PM10与气象因子的相关性进行分析得出,沙尘暴期间,大气中可吸入颗粒物的浓度与风速存在显著的正相关关系,风速越高的地区,可吸入颗粒物的浓度越大。

API(Air Pollution Index),wind speed,wind direction and other meteorological data during two dust storm events from 376 meteorological stations were studied to investigate characteristics of dust storm weather in northern China.Daily maximum instantaneous wind speed at 88% meteorological stations in northern China was more than 7.2 m\5s-1 during the two dust storm events.Daily maximum instantaneous wind speed at 31 meteorological stations was more than 17.2 m\5s-1 and the highest frequency of wind direction was WNW on April 27,2005.Daily maximum instantaneous wind speed at 81 meteorological stations was more than 17.2 m\5s-1 and the highest frequency of wind direction was N on April 28,2005.Areas with daily maximum instantaneous wind speed more than 17.2 m\5s-1 moved quickly from middle-east Inner Mongolia to northeast China.The daily maximum instantaneous wind speed was more than 17.2 m\5s-1 at 57 meteorological stations on March 30,2007 and at 68 meteorological stations on March 31,2007,and the highest frequency of wind direction was WNW on the two days.The distribution of areas with daily maximum instantaneous wind speed not less than 17.2 m\5s-1 was relatively stable on the two days.API increased quickly in dust influenced areas.On April 28,2005 API in Hohhot,Datong and Beijing was 418,500,and 500,respectively.On March 31,2007 API in Hohhot,Chifeng and Datong was 500,500,and 423,respectively.A significant positive correlation existed between the mass concentration of PM10 and wind speed during the two dust storm events.