For the validity of Fu et al. (2004) in the tropics, you might also read our recent paper entitled «Satellite - derived vertical dependence
of tropical tropospheric temperature trends» by Fu and Johanson (2005, Geophysical Research Letter, in press).
Qiang Fu and Celeste M. Johanson (26 May 2005) Satellite - derived vertical dependence of
tropical tropospheric temperature trends, Geophysical Research Letters, Vol.