SPARC Lifetimes Re-Evaluation Photocomp 2011 Lifetimes Report Chapter 5

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The calculation of photolysis (J) rates is a possible source of considerable difference between CCMs. Within the overall aims of CCMVal, and the SPARC CCMVal-2 Report, we conducted an intercomparison of model photolysis rates (see CCMVal-2 Report Chapter 6). This revealed a number of model-model differences and helped groups find some straightforward bugs. However, not all of the CCMVal CCMs took part in PhotoComp 2008, and those that did had already started their main simulations. Therefore, the model runs did not benefit from the improvements revealed by the photolysis intercomparison.

An accurate calculation of photolysis rates is essential for making a robust estimate of trace gas lifetimes. For the new SPARC Lifetimes Re-evaluation we want to make sure that all participating models calculate accurate J rates before the main simulations are started. Therefore, we are repeating PhotoComp 2008 with the same scenarios and tests. The only difference is that models should use JPL 2010 photochemical data rather than JPL 2006.

This web page provides the necessary information, which directly follows on from PhotoComp 2008.

All models are welcome to take part. To do this you will need to download a few data files, run your photolysis code and output the results in a standard format. See links below for more information.

When you have results ready please create a directory with your model name under "/project_spaces/SPARC_Lifetime/PHOTOCOMP" and upload the data to this directory of the SPARC Lifetime Archive at BADC. (For access to the SPARC_Lifetime project space at BADC please email Charlotte Pascoe). Once you have finished the transfer of your data, please notify Martyn Chipperfield by email. If you are not a CCMVal participant, and don't want to become one, you can still take part in PhotoComp by emailing your results files to Martyn Chipperfield.