Global patterns of cloud optical thickness variation with temperature and the implications for climate change

Miscellaneous · Wed Jan 01 00:00:00 EST 1992

OSTI ID:7266049

Tselioudis, G

This thesis presents a correlative analysis of cloud optical thickness and cloud temperature in large space and time scales. The analysis is designed to document and explain the patterns of cloud optical thickness variation with temperature, and to produce an understanding of cloud optical property feedbacks on climate change. The results of the global correlations between cloud optical thickness and temperature are presented. The analysis focuses on low clouds to limit variations in cloud vertical extent, particle size and water phase. Coherent patterns of change are observed on several time and space scales. On the planetary and the seasonal scales, clouds in the colder latitudes and seasons are optically thicker than clouds in the warmer latitudes and seasons. The seasonal, latitudinal, and day-to-day variations of this relation show that in cold continental clouds optical thickness increases with temperature consistent with the temperature variation of the adiabatic cloud water content, but in warm continental and in most maritime clouds optical thickness decreases with temperature. Case studies are presented to identify the cloud parameters responsible for the optical thickness changes and to resolve the atmospheric processes that produce those changes. The temperature variation of low cloud optical thickness primarily reflect changes in the liquid water content of the clouds, and changes in cloud particle size and vertical extent play a secondary role. It is proposed that an increase in the efficiency of formation of warm rain at higher temperatures relative to condensation, raises the probability of occurrence of optically thin clouds at warmer temperatures and produces the observed negative optical thickness slopes. A two dimensional radiative convective model is used to estimate the magnitude and sign of the feedback that the observed cloud optical thickness changes would produce in a climate warming scenario.

• Research Organization: Columbia Univ., New York, NY (United States)
• OSTI ID: 7266049
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CLIMATIC CHANGE
GLOBAL ASPECTS
CLOUDS
OPACITY
TEMPERATURE DEPENDENCE
DAILY VARIATIONS
LATITUDE EFFECT
METEOROLOGY
SEASONAL VARIATIONS
GEOGRAPHICAL VARIATIONS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
VARIATIONS
540120* - Environment
Atmospheric- Chemicals Monitoring & Transport- (1990-)