GEOG 131 Chapter Notes - Chapter 7.5, 18.7-18.10: Subtropics, Transpiration, Allelopathy
Document Summary
An area is only classi ed as arid if precipitation does not offset the potential loss of water through evaporation from the surface and transpiration through leaf surfaces. Factors of arid climates: descending air along the subtropics, cold ocean currents, rain shadow, distance to the ocean. Desert- dry lands often with little vegetation. Steppe- region intermediate between a true desert and a more humid climate: aka semi-arid. Subtropical deserts- general atmospheric circulation brings dry air into the subtropics. Rain shadow desert- as air descends on downward side of the mountain, it dries. Coastal deserts- form where cold, upwelling ocean currents cool the air and stabilize the atmosphere. Continental deserts- form in the interiors of some continents, far from sources of moisture, or where prevailing winds blow toward the sea. Xerophytic- species that have built in mechanism that make them tolerant to arid. Savannas- grassland in transition zone between deserts and humid regions. Prairies- outside tropics and have tall grass.
