Sea level rise rate leads global temperature?October 19, 2009
I have noticed a surprising (to me) correlation between the global average sea level and the global temperature. It appears to me that the sea level rise rate leads the temperature. The following plot shows sea level rise rate from the Jason and TOPEX satellites (from the University of Colorado web site) and the global temperature (from UAH) with a 1.1 year offset added to the temperature data to align it with the sea level rise data.
This data shows that the sea level rise rate leads the temperature – just the opposite of what I expected. Perhaps this is already obvious to other people and there is some simple, well understood explanation. I don’t know.
I started out looking at this data for an entirely different reason: to show that in today’s world a temperature increase followed by constant (or nearly constant) temperature will result in an initial sea level rise rate increase, and a subsequent dropping sea level rise rate. In other words, the equilibrium time is short. This is in contrast to Stefan Rahmstorf’s claim that a temperature increase, followed by a constant temperature will result in increased sea level rise rate that will last a millenium. I have been critical of Rahmstorf’s claim for over two years. I will deal more with this issue in a later post.
Here is how the data for this post is reduced:
Next, both sets of data were smoothed using a 1 year FWHM Gaussian filter and the sea level data was interpolated to 1 month intervals…
Then the sea level rise rate (mm/year) (time derivative of the sea level) was calculated…
The first thing that jumps out is that the temperature peak at 1998 came about one year after the corresponding sea level rise peak, and three major temperature troughs occur about one year after sea level rise rate troughs.