Widening of the tropics in global surface-air winds
摘要
An analysis of a dataset originally constructed to provide a boundary condition for oceanographic modeling reveals widening of the tropics. On the poleward side of the edges of the atmospheric Hadley cells, the surface air wind veers eastward while on the equatorial side it veers westward because of the Coriolis force, thereby making the latitude where the zonal mean zonal wind in the surface air is zero a robust indicator of the Hadley cell edges. We have detected a trend in the latitudes of those wind nulls over the world’s oceans in the Cross-Calibrated Multi-Platform (CCMP) surface air wind dataset and found that the tropics have widened by