February 28, 2007
GCRIO Program Overview
Our extensive collection of documents.
Archives of the
Global Climate Change Digest
A Guide to Information on Greenhouse Gases and Ozone Depletion
Published July 1988 through June 1999
FROM VOLUME 12, NUMBER 4, APRIL 1999
Tropospheric Aerosol Climate Forcing in Clear-Sky Satellite
Observations over the Oceans, J. M. Haywood, V. Ramaswamy, and B. J.
Soden,Science 283 (5406), 1299-1303 (1999).
A new approach to determine the direct effects of aerosols on Earths
climate combines satellite data of reflected sunlight with results from
numerical models. Geographical patterns attributable to tropospheric
aerosols are inferred by comparing radiative computations using
model-derived estimates of natural and anthropogenic aerosol distributions
with clear-sky satellite-measured solar irradiances over oceans. However,
naturally occurring sea salt is revealed as the leading aerosol
contributor to the global mean clear-sky radiation balance over oceans.
Solving the Aerosol Puzzle, J. T. Kiehl,Science 283
(5406), 1273-1275 (1999).
This overview places the research of Haywood et al. (see previous entry)
in the larger context of the issues of anthropogenic influences on
climate, particularly the role of aerosols from fossil-fuel burning and
industrial emissions. Complications result from the uncertainties in the
size and location of aerosol forcing, the interactions of different types
of aerosols, and their indirect effects. Measurements at the Earths
surface are needed to validate and improve satellite observations,
particularly examination of the precise chemical composition and physical
properties of aerosols and their vertical distribution. The validity of
3-D chemical-transport models needs to be examined with these same data.
Recent research and new observational programs (e.g., the international
Indian Ocean Experiment, NASAs Earth Observation System, and a joint
U.S.-French satellite) are viewed as steps in the coordinated integration
of observation and modeling and a reason for optimism in solving the
Guide to Publishers
Index of Abbreviations