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30 Topographic Effects on Precipitation

Part 3. Meteorology and Climatology

  1. Geoffrey L Austin1,
  2. Kim N Dirks2

Published Online: 15 APR 2006

DOI: 10.1002/0470848944.hsa033

Encyclopedia of Hydrological Sciences

Encyclopedia of Hydrological Sciences

How to Cite

Austin, G. L. and Dirks, K. N. 2006. Topographic Effects on Precipitation. Encyclopedia of Hydrological Sciences. 3:30.

Author Information

  1. 1

    The University of Auckland, Department of Physics, Auckland, New Zealand

  2. 2

    The University of Auckland, Department of Physiology, Auckland, New Zealand

Publication History

  1. Published Online: 15 APR 2006

Abstract

Topography and orography can drastically alter the wind patterns in the atmosphere that in turn can have a major effect on the geographical distribution of precipitation. The processes involved include the upslope enhancement of existing rainfall or the triggering of new rainfall in mountainous regions, and the effect of temperature or humidity contrasts between boundary layer air masses over land and oceanic areas. These processes can result in rainfall patterns ranging from a single triggered thunderstorm to widespread torrential rainfall, as occur when tropical cyclone air masses are pushed up steep coastal mountain ranges. Since the magnitude and distribution of the resulting precipitation pattern can depend critically on the wind speed and direction, as well as the terrain itself, the topographical precipitation processes often determine not only the climatic rainfall patterns of a region but also the interannual variability of this distribution.

Keywords:

  • barrier flow;
  • lee vortices;
  • lee waves;
  • monsoon circulations;
  • orography;
  • precipitation;
  • rainfall enhancement;
  • sea breeze;
  • seeder-feeder;
  • topography;
  • triggered convection