Measurements and modeling of the effect of convective clouds on the upper tropospheric moisture budget

Conference · Sat Apr 01 04:00:00 EST 1995

OSTI ID:83160

Bisson, S E; Goldsmith, J E.M. ^[1]; Del Genio, A D ^[2]

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1. Sandia National Labs., Livermore, CA (United States)
2. NASA/Goddard Space Flight Center, New York, NY (United States)

The goal of this study is to determine the upper tropospheric moisture budget associated with convective events and, in particular, to extend process models to higher altitudes than have been achieved previously. Although upper tropospheric moisture concentrations are several orders of magnitude lower than those near the surface, upper tropospheric moisture exerts an important influence on climate. On a per-molecule basis, greenhouse absorption due to water vapor is about one hundred times more effective at high altitudes than at low altitudes. Several one-dimensional radiative convective models have been used to demonstrate the importance of upper tropospheric moisture on climate. These models show that for a given fractional increase in water vapor at a given altitude, the response or change in surface temperature is qualitatively the same. Figure 1 shows the change in surface temperature for a 50% increase of the specific humidity in a 40-mbar layer in clear skies. At present, considerable controversy exists over the nature of the vertical redistribution of water vapor in a changing climate, particularly the distribution of water vapor in the upper troposphere. Because suitable data are lacking, this controversy is also reflected in the cumulus parameterization schemes currently used in models. Understanding upper tropospheric moistening processes is therefore of prime importance in addressing the water vapor feedback question.

• Research Organization: USDOE Office of Energy Research, Washington, DC (United States). Environmental Sciences Div.
• OSTI ID: 83160
• Report Number(s): CONF-940277--; ON: DE95009951
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CLIMATE MODELS
CLOUDS
CONVECTION
DISTRIBUTION
HUMIDITY
MOISTURE
TROPOSPHERE
WATER VAPOR