It arises because of the horizontal divergence . 它是由于水平辐散而出现的。
2.
Low - level cyclones usually imply horizontally confluent flow and vertically rising air resulting in inclement weather . low - level anti - cyclones bring in fine and stable weather due to horizontally diffluent flow and vertically sinking air 低空气旋表徵水平汇聚、垂直上升的不稳定气流，可以导致恶劣天气产生；低空反气旋则代表水平辐散、垂直下沉的稳定流场，伴随著晴朗的天气。
