Estimated PDFs of Climate System Properties Including Natural and Anthropogenic Forcings
Name
MITJPSPGC_Rpt126.pdf
Size
873.36 KB
Format
Adobe PDF
Checksum (MD5)
eed896ee11a90d9bc0e199bdd0753dcf
Author(s)
Forest, Chris Eliot.
Stone, Peter H.
Sokolov, Andrei P.
Date Issued
September 2005
Publisher
MIT Joint Program on the Science and Policy of Global Change
Citation
Report no. 126
Series/Report no.
126
Abstract
We present revised probability density functions (PDF) for climate system properties (climate sensitivity, rate of deep-ocean heat uptake, and the net aerosol forcing strength) that include the effect on 20th century temperature changes of natural as well as anthropogenic forcings. The additional natural forcings, primarily the cooling by volcanic eruptions, affect the PDF by requiring a higher climate sensitivity and a lower rate of deep-ocean heat uptake to reproduce the observed temperature changes. The estimated 90% range of climate sensitivity is 2.4 to 9.2 K. The net aerosol forcing strength for the 1980s decade shifted towards positive values to compensate for the now included volcanic forcing with 90% bounds of -0.7 to -0.16 W/m2. The rate of deep-ocean heat uptake is also reduced with the effective diffusivity, Kv, ranging from 0.25 to 7.3 cm2/s. This upper bound implies that many coupled atmosphere-ocean GCMs mix heat into the deep ocean (below the mixed layer) too efficiently.
Description
Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).
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