Every 'skeptic' seems to have his own pet argument/myth. For most it's "global warming has stopped". For eric c it's "there's no hot spot".
The basis of this myth is that there should be an amplification of any warming at the Earth's surface in the tropical troposphere, which should create a "hot spot". In theory, instruments (radiosondes) on weather balloons should be able to measure this hot spot. In reality, they haven't seen one.
So this tells you either the climate models are wrong or the data is wrong. Some people jump on this and conclude the models must be wrong. The problem with this line of thinking is that if there's warming on the surface, there should be a 'hot spot' regardless of what's causing the warming. And we know there's warming. So the logical conclusion is that there's a problem with the radiosonde measurements. RealClimate has a good discussion of some of those problems here.
Radiosondes themselves have significant problems and were also not designed for detection of small climate changes. These problems have been well documented anecdotally, and have been dutifully acknowledged by those who have published trends in radiosonde temperatures. The cautions urged by these researchers in interpreting the results have not always been taken on board by others however.
Few if any sites have used exactly the same technology for the entire length of their record, and large artifacts have been identified in association with changes from one manufacturer to another or design upgrades by the same manufacturer. Artifacts have even been caused by changing software and bug fixes, balloon technology, and tether lengths. Alas, many changes over time have not been recorded, and consistent corrections have proven elusive even for recorded changes...
A recent study confirmed that when you take radiosonde errors into account, there is no more discrepancy bewteen data and models.
The grey band is the real 2-sigma spread of the models (while the yellow band is the spread allowed for in the flawed Douglass et al test). The other lines are the different estimates from the data. The uncertainties in both preclude any claim of some obvious discrepancy - a result you can only get by cherry-picking what data to use and erroneously downplaying the expected spread in the simulations.
So this myth is fatally flawed for 2 major reasons.
- The radiosonde data isn't good enough to preclude the existence of the 'hot spot'.
- The hot spot should exist regardless of the cause of surface warming. If you're arguing global warming is caused by the Sun or other 'natural' causes, you would still expect a hot spot to be there.
Edited by dana1981 - 3/31/2009 at 09:26 pm