date: Wed, 31 Oct 2001 11:14:50 GMT
from: Michael Tsimplis <mntatXYZxyz.soton.ac.uk>
subject: Re: global sea-levels - latest
Thanks for the information. I think there are two issues which are quite different:
1. present rate of sea level rise (and certainly we do not have data for the southern ocean and the arctic but on the other hand most people will doubt the ability of the altimetric records to give yet accurate estimates). The rates of sea level are based on direct measurements not on estimates of thermal expansion, these only come into play when one tries to break the sea level number down to its parts.
2. whether the model values (IPCC) provide good estimates. My view is that they don't but this is recognised in the IPCC report where the regional variability
is shown to be remarkably different between models. There are of course issues
about what the bottom of the sea is doing or how would the removal of ice-sheets affect land movements but I would stand by the IPCC assessment as I know some of the people and trust them while in the past the altimetric community has got it hopelessly wrong. On the other hand I am aware that they are trying to get funding of JASON2 and clearly that is a good objective.