甘肃省“4.22”特大沙暴分析

本文通过对一次特大沙暴(黑风)天气过程气象要素时空演变的分析,研究了河西黑风与冷空气移动的关系,指出翻越天山经南疆进入河西走廊是引起河西春季黑风的重要冷空气路径。通过对黑风的环流、风速日变化及锋面坡度的分析,并着重研究了热力因子在黑风过程中的重要作用,指出强沙暴在白天提供的正反馈机制,使黑风不断加强;傍晚前后,沙暴提供的负反馈作用则促使黑风迅速减弱。据此,构造了黑风发生发展的正反馈模型,并提出了黑风预报的着眼点。

ON AN EXTRAORDINARY HEAVY SANDSTORM ON APRIL 22ND IN GANSU

By analysing the time and space variations of the meteorological elements in the course of a heavy sandstor m, the essay surveys the relationship sandstorm and the movement of the cold air. It points out that the cold air which forms the sandstorm in Spring in the Gansu Corridor finds its way over Tianslzan Mountains through the southern part of Xinjiang Uighur Autonomous Region down into the Gansu Corridor. Having studied the circulation, the speed the day variance and the slope of the cold front, and giving emphasis on the important role of the heat element in the course of the sandstorm, the essay points out that. The sandstorm provides itself with positive regenerative machine and intensifies in the day-time. In the evening, it provides itself with negative regeneration and subsides quickly. A positive regenerative model of the outbreak and development of the sandstorm and a focal point in its forecast are given.