GLY-1103 Lecture Notes - Lecture 11: Desert Varnish, Antarctica, Dune
Document Summary
Definition- no permanent water, vegetation covers >15%, less than 10 in of annual rainfall. Geologic features- exposed bedrock, accumulated clasts, unweathered sediment, precipitated salts, windblown sand, desert varnish. 5 types: subtropical (sahara, arabian, kalahari, rainshadow (oregon and washington, coastal (alacama, continental interiors (gobi, polar (antartica) Subtropical- equator 0 degrees latitude, largest deserts: solar energy evaporates water which rises as hot, moist air, rising air cools and expands, forming abundant rain, moisture flows to the north and south. Subtropics- 20-30 degrees north and south: sinking air wicks water, landscape below dries. Rain shadow- moist ocean winds drive over mountains: on front side of range, air rises, expands and cools (rainforests, on backside, air stripped of moisture sinks (deserts) Coastal- cold air over cold water hold little moisture: the air absorbs moisture when it interacts with land, alacama desert (peru) is the driest place on earth. Interior- air loses moisture as it moves across continents: land far from ocean can be arid.
