GL102 Lecture Notes - Lecture 15: Abrasive Blasting, Desert Pavement, Deflation
Document Summary
Distribution and causes of dry lands dry regions cover 30% of earth"s land surface. Water-deficient regions two climatic types are recognized desert (arid) steppe (semiarid. The steppe is a more humid variant of the desert. Vicinity of the tropics of cancer and capricorn. Hot air equilateral low regions rise and spreads out. At 20 - 30 degrees latitude, air sinks. At 30 degrees n and s latitude, high pressure dominated as subtropical highs, and air subsides. Polar desserts climate is very dry and cold. Mean summer temperatures of -1. 5 to 2. 0 degrees celsius. Mean winter temperature of -32 to -23 degrees celsius. Much of canada"s arctic is polar desert precipitation only 10-20 cm. Weathering mechanical weathering is common and produces unaltered rock fragments some chemical weathering produces clay thin soils iron oxides (desert varnish) They have ephemeral streams, which carry water only during rainfall. Practically all streambeds are dry most of the time.
