Climatic Change

, Volume 42, Issue 1, pp 327–339

Conceptual Framework for Changes of Extremes of the Hydrological Cycle with Climate Change

Authors

  • Kevin E. Trenberth
    • National Center for Atmospheric Research
Article

DOI: 10.1023/A:1005488920935

Cite this article as:
Trenberth, K.E. Climatic Change (1999) 42: 327. doi:10.1023/A:1005488920935

Abstract

A physically based conceptual framework is put forward that explains why an increase in heavy precipitation events should be a primary manifestation of the climate change that accompanies increases in greenhouse gases in the atmosphere. Increased concentrations of greenhouse gases in the atmosphere increase downwelling infrared radiation, and this global heating at the surface not only acts to increase temperatures but also increases evaporation which enhances the atmospheric moisture content. Consequently all weather systems, ranging from individual clouds and thunderstorms to extratropical cyclones, which feed on the available moisture through storm-scale moisture convergence, are likely to produce correspondingly enhanced precipitation rates. Increases in heavy rainfall at the expense of more moderate rainfall are the consequence along with increased runoff and risk of flooding. However, because of constraints in the surface energy budget, there are also implications for the frequency and/or efficiency of precipitation. It follows that increased attention should be given to trends in atmospheric moisture content, and datasets on hourly precipitation rates and frequency need to be developed and analyzed as well as total accumulation.

Copyright information

© Kluwer Academic Publishers 1999