tag:blogger.com,1999:blog-9959776.post5252491512215187721..comments2024-02-15T04:42:41.606+00:00Comments on James' Empty Blog: More sensitivity?James Annanhttp://www.blogger.com/profile/04318741813895533700noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-9959776.post-84965219553379904162014-01-07T15:11:26.248+00:002014-01-07T15:11:26.248+00:00Interesting if the thing about Fasullo and Trenber...Interesting if the thing about Fasullo and Trenberth is true. A few years ago it was all the rage to talk about a correlation between sensitivity and aerosol forcing in the CMIP3 ensemble. When I looked into the details it became apparent that there was considerable technological stratification in the ensemble: that some models were far more advanced/developed than others. And it turned out, for some reason, that the more advanced ones tended to have higher sensitivities. <br /><br />The key technology factor for aerosol forcing was whether or not the model included explicit aerosol-cloud interaction. Those that did understandably tended to produce stronger aerosol forcing. And those were almost unanimously at the high-end of sensitivity.<br /><br />There were also key differences in explicit inclusion of natural aerosol species, like some organic aerosols, dust, sea salt. Since aerosols affect the whole cloud-precipitation system, and therefore relative humidity, presumably a more realistic aerosol implementation would have some effect on the climate process focus of Fasullo and Trenberth.<br /><br />I have to say I'm way out of my depth on that last suggestion, but, on a general point, from what I know of the CMIP3 ensemble it's entirely plausible to me that their sensitivity correlation was mostly due to this stratification of model complexity in some respect. The CMIP5 ensemble seems mostly to have more equality, complexity-wise.Paul Shttps://www.blogger.com/profile/15275182941476518621noreply@blogger.com