当水平风的垂直切变达到（ ）,水平切变达到（ ）时，常有晴空湍流发生
A.1-2mps/100m，5-6mps/100km
B.1-2mps/100km，3-5mps/100m
C.1-2mps/100m，5-6mps/100m
D.1-2mps/100km，5-6mps/100m
正确答案是A