From my comments to this post on comparing IPCC forecasts to reality, I had a couple of thoughts on satellite temperature measurement that I wanted to share:
- Any convergence of surface temperature measurements with satellite should be a source of skepticism, not confidence. We know that the surface temperature measurement system is immensely flawed: there are still many station quality issues in the US like urban biases that go uncorrected, and the rest of the world is even worse. There are also huge coverage gaps (read: oceans). The fact this system correlates with satellite measurement feels like the situation where climate models, many of which take different approaches, some of them demonstrably wrong or contradictory, all correlate well with history. It makes us suspicious the correlation is a managed artifact, not a real outcome.
- Satellite temperature measurement makes immensely more sense – it has full coverage (except for the poles) and is not subject to local biases. Can anyone name one single reason why the scientific community does not use the satellite temps as the standard EXCEPT that the "answer" (ie lower temperature increases) is not the one they want? Consider the parallel example of measurement of arctic ice area. My sense is that before satellites, we got some measurements of arctic ice extent from fixed observation stations and ship reports, but these were spotty and unreliable. Now satellites make this measurement consistent and complete. Would anyone argue to ignore the satellite data for spotty surface observations? No, but this is exactly what the entire climate community seems to do for temperature.
I noticed you were able to post on Pieke’s blog – I can’t sign in.
http://sciencepolicy.colorado.edu/prometheus/
I wanted to point out that Pieke is comparing the IR4 predictions to the actuals from 2000. IR4 was released in 2007 so one would expect a good match between the models and the recent past. What we need to do is watch for divergance from 2007 on.
This means Pieke’s blog gives an extremely misleading representation of the accuracy of the models. He should clearly indicate on his graphs when the model results were published.
the only even loosely plausible reason i have heard is that the surface record goes back further. 30 years is not a particularly long time to establish a trend in something with as long a cycle as climate.
this is still not a good argument for using it to measure the change currently occurring however. but it does mean that if we use surface data pre 1979 and satellite afterwards, it is not a purely apples to apples comparison.
but that does not seem to be a good reason to prefer a flawed and incomplete record to the satellite record which not only uses better methodology and has a wider footprint, but has been verified by an independent source (weather balloon data) see ball etc on comparing MSU lower trop data to noaa weather balloons. they are statistically indistinguishable.
i suspect another reason (though it is certainly not a valid one) for preferring the surface data is that it began, in a widespread fashion owing to the spread of thermometers, in the late 1800’s as the world was still emerging from the little ice age, one of the coldest period in the last 10,000 years. given climate’s tendency to revert to the mean, any data set anchored at that time will have a built in tendency to show warming. this is essentially like taking the temperature in february as baseline and then commenting “my, it certainly is much warmer most of the time.”…
Raven, he gives the details in his post. Putting them on the graph would be needless clutter.
The only good reason is because it doesn’t cover at least 40-100 years. Unfortunately by the time that we have 40-50 years of satellite measurements we won’t be getting much rewards for proving the alarmists wrong, we would have moved on to other issues.
What is remarkable with this is that for climate change short term satellite measurements are not preferred over a mishmash of flawed surface measurements, while for ozone depletion most policy decisions were based on a very short sample of satellite measurements while surface UV levels didn’t support the alarmist view that we’re going to die of cancer.