Retreat of glaciers since 1850 doing so due to transient local weather conditions, which have brought more precipitation and cloudier, cooler summers since 2002. Tropical glaciers are located between the Tropic of Cancer and the Tropic of Capricorn, in the region that lies 23° 26′ 22″ north or south of the equator. Strictly, a tropical glacier is located within the astronomical tropics; the area where the annual temperature variation is less than the daily variation, and is within the oscillation area of the Intertropical Convergence Zone. Tropical glaciers are the most uncommon of all glaciers for a variety of reasons. Firstly, the regions are the
Asymmetry of the Intertropical Convergence Zone the geometries of the continents. According to observations, the Sea Surface Temperature (SST) of ITCZ in the Northern Hemisphere is higher than the same latitude in the Southern Hemisphere. The asymmetry of ITCZ is triggered by the asymmetric SST distribution, which has been verified by General Circulation Model (GCM). What is more, because the Cross Equator SST Gradient (CESG) is southward, the cross equator northward wind, which decelerates trade winds north of the equator and accelerates those south of the equator due to Coriolis force, is originated. Thus the evaporation of the northern tropics is weakened, thereby cooling down the