We have analyzed independent radiosonde observations of surface and tropospheric temperature, which confirm the pattern of greater surface warming since 1979 in the tropics. Analysis of temperatures and lower-tropospheric lapse rates, computed from individual radiosoundings, indicates that the differential temperature trends are associated with lapse-rate changes. Spatially coherent decreases in the static stability of the tropical atmosphere are observed during 1979-97. These trends exceed unforced static stability variability simulated by state-of-the-art coupled ocean- atmosphere climate models.
Radiosonde observations are available for a longer period than the MSU data and so afford the opportunity to examine multi-decadal variability in the vertical temperature structure of the atmosphere. The differential temperature trends and lapse-rate changes seen during the satellite era are not sustained back to 1960, which suggests a different mechanism was operating in the recent period than in earlier decades.
![](images/flag.png)
![](images/blue_ribbon.png)