Lately, I’ve been looking at the differences in the two satellite temperature records. I first blogged about how there is a divergence in the two time series (RSS and UAH) with power at 1 year. In the same post, I noted that there appears to be a step in the difference time series, but at the time I did not pursue it further. Yesterday, I finally got around to blogging about the apparent change point in the difference time series.

I think I’ve exhausted the options of looking at only the global monthly temperature anomaly time series. Instead, this post will be about spatial differences in the two records. I obtained gridded data from UAH and RSS.

I was hoping that the reason for the 1992 jump would be apparent by looking at the gridded data. I made an animation looking at the difference map for each month. I did not see any reason why there would be a change point in the global time series. But I did notice something else. The difference between the two time series appeared to be greater near the poles than at the equator.

Making a map of the errors was easy, and is shown below.

It’s clear from the map that there is more agreement between the two measurements near the equator. Also, there is also better agreement over the oceans. Obviously, that means the best agreement is over the tropical oceans, and the worst agreement is over the polar land areas. I’ve blown up the area around the North Pole.

This shows that the most error, in the Northern Hemisphere, occurs at the north end of Greenland. This is consistent with the observation that polar land areas have the greatest difference between the time series. There is also the yellow ring of large difference that occurs where the continents meet the Arctic Ocean.

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