11.3
An apparent multi-decadal trend in shortwave cloud forcing over the tropical Pacific
Richard C. J. Somerville, SIO/University of California, La Jolla, CA; and G. L. Potter, M. Kanamitsu, J. J. Hnilo, and J. Woolen
The NCEP/NCAR reanalysis of atmospheric data beginning in 1948 has provided an opportunity to study a consistent 50-year record of assimilated weather observations. Through the examination of several fields, we find an apparent long-term decrease in relative humidity and cloud amount in the tropical Pacific. As a result, the shortwave cloud radiative forcing decreased nearly 15 Wm-2 over the entire period. Two major questions arise: the first is the extent to which the trend over the 50-year period is a real phenomenon rather than the result of observing system evolution. The second is, if the phenomenon is at least partially real, what is its cause?
Session 11, Climate Forcing (Parallel with Sessions 10 & 12)
Wednesday, 17 January 2001, 1:30 PM-5:00 PM
Previous paper Next paper