cc: "jason.lowe@metoffice.com" date: Thu Apr 30 15:25:32 2009 from: Tim Osborn subject: Re: Query with thermal expansion / temperature input data to: "Brown S." , Nigel Arnell Hi Sally, The data came from Malte Meinhausen by way of Sarah Raper. An alternative answer to that question is that the data came from the AR4-version of MAGICC 4.2. As I indicated earlier to Nigel, my understanding is that MAGICC (AR4-version) typically overestimated thermal expansion compared with GCMs, which is one of the reasons why MAGICC sea level rise wasn't used in AR4. Appendix 10.A of AR4 WG1 discusses this. I believe there is a post-AR4 version of MAGICC which does a better job with thermal expansion; I/we could ask Malte Meinhausen or Sarah Raper if we can have the thermal expansion from that version. Re. CO2. Is this the line that you are asking about: "CARBON CYCLE FEEDBACK SETTING: default (1)" As far as I know, the "default" strength of the carbon cycle feedback is not zero strength (i.e. CO2 feedback turned off), but rather is the "standard" CO2 feedback strength as described in Fig. 10.29 of AR4 WG1. That is certainly how it was explained to me before, but I will check this with Sarah Raper to make sure. Hope that helps, Tim At 13:54 30/04/2009, Brown S. wrote: Hello, We are finalising the sea-level scenarios and have checked the output data with Jason Lowe, who has some queries. Thermal expansion values (in particular) are higher than Table 10.7 (p820 WG1 IPCC 2007), and also temperature seems a bit higher. Where did the data come from? Jason wanted to check about the CO2 concentration - was this turned on during the runs (just says the default setting is 1 - see accompanying file as an example)? How does this follow with p5 of the Experimental Design Note (I have V5.1) which says 'The project therefore scales each climate model pattern by global temperatures estimated with its own set of tuned MAGICC4.2 parameters, assuming a medium carbon cycle feedback and a default radiative forcing for doubled CO2 concentration of 3.7 W/m2.'? Sally ----------------- Sally Brown School of Civil Engineering and the Environment University of Southampton 02380 592883 (new telephone number)