Identification

Title

The changing character of precipitation

Abstract

From a societal, weather, and climate perspective, precipitation intensity, duration, frequency, and phase are as much of concern as total amounts, as these factors determine the disposition of precipitation once it hits the ground and how much runs off. At the extremes of precipitation incidence are the events that give rise to floods and droughts, whose changes in occurrence and severity have an enormous impact on the environment and society. Hence, advancing understanding and the ability to model and predict the character of precipitation is vital but requires new approaches to examining data and models. Various mechanisms, storms and so forth, exist to bring about precipitation. Because the rate of precipitation, conditional on when it falls, greatly exceeds the rate of replenishment of moisture by surface evaporation, most precipitation comes from moisture already in the atmosphere at the time the storm begins, and transport of moisture by the storm-scale circulation into the storm is vital. Hence, the intensity of precipitation depends on available moisture, especially for heavy events. As climate warms, the amount of moisture in the atmosphere, which is governed by the Clausius– Clapeyron equation, is expected to rise much faster than the total precipitation amount, which is governed by the surface heat budget through evaporation. This implies that the main changes to be experienced are in the character of precipitation: increases in intensity must be offset by decreases in duration or frequency of events. The timing, duration, and intensity of precipitation can be systematically explored via the diurnal cycle, whose correct simulation in models remains an unsolved challenge of vital importance in global climate change. Typical problems include the premature initiation of convection, and precipitation events that are too light and too frequent. These challenges in observations, modeling, and understanding precipitation changes are being taken up in the NCAR “Water Cycle Across Scales” initiative, which will exploit the diurnal cycle as a test bed for a hierarchy of models to promote improvements in models.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7fn16q0

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

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keyword value

Text

originating controlled vocabulary

title

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reference date

date type

publication

effective date

2016-01-01T00:00:00Z

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Dataset reference date

date type

publication

effective date

2003-09-01T00:00:00Z

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Use constraints

Copyright 2003 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be "fair use" under Section 107 of the U.S. Copyright Act or that satisfies the conditions specified in Section 108 of the U.S. Copyright Act (17 USC §108, as revised by P.L. 94-553) does not require the AMS's permission. Republication, systematic reproduction, posting in electronic form on servers, or other uses of this material, except as exempted by the above statement, requires written permission or a license form the AMS. Additional details are provided in the AMS Copyright Policy, available on the AMS Web site located at (http://www.ametsoc.org/AMS) or from the AMS at 617-227-2425 or copyright@ametsoc.org.

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

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