Causes of Sand-stormy Weather in Northern China and Contral Measures

In northern China, the number of days with sand stormy weather has been decreasing in the past 40 years, but in the spring of 2000, an unprecedented heavy sand stormy weather with high frequency took place, which exerts adverse effect on traffic, environmental management and people's daily life and work. Especially, it brought direct damage to Beijing, Tianjin and their neighbouring areas, which has aroused even more extensive concern of personages of various circles. Therefore, the reasons and the rational suggestions are proposed in this paper. The sand stormy weather is the result of the special geographic environment and weather conditions. Changes in the number of days of strong wind are the reflections of the periodical change in climate. Why the strong sand stormy weather took place is that the anti El Nin～o case is at top, and the land cover deteriorates in the whole area but with part area improving. The dust weather mainly originated from mid west Inner Mongolia and northwest of Hebei Province. The dust is mainly consisted of soil dust from the origination area and the trace. The ground bare soil and sandy dust from construction site in urban extension areas also supplied materials for the local dust. In order to alleviate and control the dust damage, some suggestions were proposed as following: Firstly, the natural vegetation must be restored through planting tree or grasses in cultivated land instead of planting crops. Especially effective ecological protective shield must be established for Beijing and Tianjin city. The bare land of urban marginal areas must be treated in order to control local dust. Secondly, eco environmental construction must be paid more attention to during implementing Western Development Plan. Ecological benefits must be combined with economic and social benefits. Finally, the system for monitoring and predicting the sand stormy weather must be established and improved. Study on controlling and alleviating the dust disaster also need to be done.