HR: 08:40h
AN: A11E-03 INVITED     [Abstracts]
TI: Response of Global Ocean Temperature to the Sun's Quasi-Decadal UV Radiative Forcing of the Stratosphere
AU: * White, W B
EM: wbwhite@ucsd.edu
AF: Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0230 United States
AB: Earth's climate system experiences quasi-decadal signals in the tropical global-average temperature in the upper ocean ($<$TO$>$), the troposphere ($<$T5km$>$), and lower stratosphere ($<$TS$>$), with changes of 0.1K, 0.2K, and 1.0K respectively. These temperature signals fluctuated in fixed phase with the quasi-decadal signal in the Sun's irradiance. White et al. (2003a) diagnosed the thermal budget of the quasi-decadal $<$TO$>$ signal in the tropics, finding the anomalous $<$TO$>$ warming tendency driven by downward sensible-plus-latent heat flux ($<$QS + QL$>$) anomalies. Here we find the latter driven by anomalously warm air-sea temperature differences, with $<$T2m$>$ anomalies larger than $<$SST$>$ anomalies and leading by $\sim$1 year. To determine how this happens, we diagnose the thermal budget of the quasi-decadal signal in the tropical atmosphere (20$^{\circ}$S to 20$^{\circ}$N) using the NCEP/DOE reanalysis data set. We find the quasi-decadal signal in the Sun's UV radiative forcing of the lower stratosphere temperature anomalies balanced by anomalous longwave radiation to space and to the troposphere below, and by anomalous thermal convection. The latter produced an anomalous warming tendency in the lower troposphere during anomalous cool lower stratosphere temperature. It has two components; i.e. the anomalous convection of the mean thermal gradient and the mean convection of the anomalous thermal gradient. We find the anomalous warming tendency in the lower troposphere driven principally by the latter component, yielding positive anomalous air-sea temperature differences and downward $<$QS + QL$>$ anomalies that are responsible for the anomalous $<$TO$>$ warming tendency.
DE: 7538 Solar irradiance
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
DE: 3359 Radiative processes
DE: 4504 Air/sea interactions (0312)
DE: 4572 Upper ocean processes
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting