2004年北京地区一次扬沙天气过程数值预报分析

本文在对沙源和实况气象场分析的基础上,利用北京城市气象研究所发展的区域沙尘耦合模式,对2004年3月29日北京及周边地区扬沙天气过程进行数值研究.模式预报出大风、垂直速度等气象条件要素演变,表明导致此次沙尘过程的发生、发展主要因素是大风、上升气流等.从天气实况沙尘图与预报沙尘区随时间演变过程看,模式预报的沙尘范围和强度与实况结果基本相符;沙尘数值预报模式能够较好地预报出此次沙尘过程发生的时间、地点、范围和移动路径等,较准确地描述了本次沙尘过程的形成演变和移动等特征.从模式预报的北京地区沙尘浓度的垂直廓线和沙尘强度表明本次沙尘的沙源以本地扬沙为主.

Numerical Forecast and Analysis on a Blown Sand in Beijing in 2004

Based on analysis of sand source of sand dust and actual meteorological field, the regional sand dust model developed by Institute of Urban Meteorology is used to forecast the blown sand occurred on 29 March, 2004 in Beijing and the surrounding areas. With the model, the evolution of weather condition elements as gale, and its vertical velocity are forecasted. It indicates that the occurrence and development of this sand dust are resulted mainly from strong wind and updraft. From the weather situation and blown sand map and evclvement of forecasted sand dust area with time, the forecasted sand-dust area and its intensity basically match with the real situation. The numerical sand-dust forecast model correctly forecasted the time, location, range and moving route of the blown sand and precisely depicted the characteristics of the formation, evolvement and migration of this blown sand. According to forecasted. The forecasted vertical profile of sand-dust density and sand-dust intensity in Beijing region show that the dust aerosol comes from the local dust source.