Geomorphological Significance of Air Flow over Saucer Blowout of the Hulun Buir Sandy Grassland
呼伦贝尔沙质草原碟形风蚀坑表面气流及其意义

Blowouts in the Hunlun Buir sandy grassland develop in a medium wind energy environment,and is the main type of Aeolian landscapes in this area.Saucer blowout is a specific phase in blowout development.The surface airflow dynamics and its relation with the geomorphological development of saucer blowouts are measured and analyzed in the paper.Measurements show that airflows diffuse in the wind entrance of blowouts,the wind speed gradually weaken to be the smallest at the bottom of blowouts;airflows converge into torrent at rear of blowouts,the wind speed increase sharply to be the highest at the top of accumulated sands.The back rim of blowouts retreat under airflow ablation,afterwards blowouts expand along the wind direction,simultaneously,a lot of sands are transported from blowouts to deposit on grassland behind depression,appearing fan shape.Being driven alternatively by winds from northwest,west and southwest,blowouts in the Hunlun Buir sandy grassland expand towards southeast,east and northeast directions respectively.Finally,blowouts develop into large trough ones along strong wind energy direction and resultant sand transporting direction.