Analysis on Circulation Difference of Sandstorms with Different Intensities in Ningxia
CHEN Nan;CHEN Xiao-guang;ZHAO Guang-ping
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Key Laboratory of Meteorological Disaster Preventing and Reducing of Ningxia, Yinchuan 750002, China;2. Lanzhou Institute of Arid Meteorology, China Meteorological Administration, Lanzhou 730020, China
The circulation difference feature of sandstorm with different intensities at the same period of Ningxia was diagnostically analyzed using the sandstorm process data of Ningxia in 1970-2003 and reanalyzed global daily data of NCEP/NCAR(1971-2000),according to the sandstorm intensity standard.Results show that the frequencies of very severe,severe and general sandstorms have obvious different under different circulation backgrounds,one ridge and one trough pattern,northwest route cold air path is the most main circulation and cold air pattern in very severe and severe sandstorm process of Ningxia region;since the intensity and location of Ural high pressure ridge,Baikal cold low pressure,Mongolia cyclone and surface cold high pressure are different,the caused sandstorm intensities have significantly differences.At same time,the different distributions of upper level westerly jet on 200 hPa is closely related to the intensity of Ningxia sandstorm.