Based on the available observation data from 102 meteorological stations in Beijing-Tianjin-and-Hebei region from 1954 to 2002, the changing characteristics of dust-storms and severe group dust-storms in this area are analyzed.

As a result, 99 severe group dust-storms have been found and confirmed in the eastern part of Northwest China in 1954-2001.

A medium-range synoptic analysis of Strong dust storm on 12 April 2000;

In this paper,the dustfall characteristics during the period from April to June and the strong dust storm events in a zone sheltered by 24-year-old artificially afforested forest of Populus simonii for sand fixation over the Horqin Sandland are studied by measuring some parameters of dustfall at some field stationed observation sites.

By using the reanalysis data of NCEP(1°×1°),the dry intrusion characteristic of a strong dust storm process occurred in the Hexi Corridor from April 9 to 10,2006 was analyzed.

This paper researched the characteristics and causes of strong sandstorms invading the middle area of Gansu through analyzing the weather system by using the high and surface data from 1970 to 2006.

The strong sandstorm and cold wave weather process were occurred from the west toward the east in Hetian area during Apr.

The high-circumfluent pattern of strong sandstorm in Gansu province from 1995 to 2002 was analyzed by using the high and surface meteorological data.

For summer clustering severe dust storms.

Using gridded upper-air and surface wind data extracted from the NCEP/DOE reanalysis-2 project and the time series of severe dust storms occurred over northern China in spring from 1979 to 2002,the relationship between the severe dust storm frequency and the Asian tropospheric wind field is examined.

The research on time series fractal characteristics of severe dust storm in the recent 49 years in North China shows: The time series of severe dust storms in North China has fractal characteristics and its correlative dimension is 3.

During the spring(March～May) of 2000～2002, twelve severe dust storms occurred in the northern China.

The circulation and meso-scale synoptic analysis was conducted on a severe dust storm event on April 8 2001.

The circulation and meso-scale synoptic analysis was conducted on a severe sandstorm event on April 8,2001.

The paper is based on real-time diagnosis about three major factors producing severe sandstorm, they are strong cold air, thermal instability and ground layer environment.