Patrick Ray May 23, 2016 08:36
Fellow
| Management via Measurement team, Last day to make refinements to your proposal. Looking forward to seeing the final version. I have a personal interest in your proposal as it intersects with my work substantially. Here's a question - where I apply them, the GCMs have very poor performance in precipitation extremes, both because they have difficulty at the daily and sub-daily timescale (but are more useful at the longer timescales), and because they often struggle with the underlying climate drivers (whether sea surface temperature oscillations affecting regional climate or local convective behavior contributing directly to extremes). If possible, could you comment on the performance of the GCMs you have used to give meaningful information for Bayesian updating of historical observations of precipitation extremes? Thank you. Best of luck. |
Colin Sullivan May 23, 2016 10:44
Member
| Proposal contributor Thanks, patrickray. In other words, is the degree of adherence to approximate CC scaling, as shown by an GCM, appropriate given the relationship between temperature and precipitation extremes exhibited in historical observational data? If observations show a relationship that suggests temperature is not the main driver of extreme precipitation, a GCM should do the same, lest it may be simulating physics improperly in that region. Even if that GCM shows a similar marginal distribution of extreme precipitation as compared to historical observations, if it does not also appropriately capture the precipitation extremes' dependence on temperature as shown by precipitation, it is more likely that GCM only appeared to be skillful and for the wrong physical reasons. Hence, it should be treated as less reliable. This is done formally through a Bayesian architecture. From a business perspective, the most important feature of this model is that it seeks to quantify uncertainty in any extreme (say, a 5-year return level) -- if all GCMs are doing a poor job, the uncertainty will be wider. |
Patrick Ray May 23, 2016 01:25
Fellow
| Very thoughtful response. Thank you. I look forward to discussing this with you in the future. Good luck. |
Colin Sullivan May 24, 2016 03:13
Member
| Proposal contributor Thanks for your question! If any others come up feel to ask here or get in contact directly.
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