African dust in Florida clouds

摘要

If you live near a desert you expect to get dusty every now and again. Strong winds bounce sand grains across the desert surface, which in turn blast micrometre-sized particles into the air, where they blow downwind and eventually land on you. Desert dust might not seem to be a problem in a lush tropical environment such as Florida, but as our view of Earth has improved it has become clear that dust is blowing everywhere and seeping into everything. As they report in Geophysical Research Letters, Sassen et al. and DeMott et al. show that dust from the Sahara Desert in Africa can have an impact on clouds over Florida (Fig. 1). Sassen previously found that dust from Asia was affecting clouds over the western United States.