Posts by old_user18703

1) Message boards : climateprediction.net Science : Another State of the Earth System? (Message 8790) Posted 7 Feb 2005 by old_user18703 Post: On page 25 of this paper http://www.stabilisation2005.com/day2/steffen.pdf they have an arrow pointing to 5-6c region with the words 'Shift to Another State of the Earth System?'. Just curious as to what they could possible be talking about? Runaway greenhouse effect? Ice age? Something unknown? Cheers, Hasse
2) Message boards : climateprediction.net Science : CP too coarse a grid? (Message 7696) Posted 27 Jan 2005 by old_user18703 Post: > I guess I'd like to know what the person asking the question means by > "reliable". > > Not sure if you have seen this > > http://www.climateprediction.net/science/model-intro.php > > introductory writeup on climate models, what they can and can't do. And this > writeup at realclimate.org on whether climate modelling is a science: > > http://www.realclimate.org/index.php?p=100 Cheers for the realclimate article link. Hadn't read that piece eventhough I go there often enough. I read the model introduction article before, but just didn't put two and two together. So in essence, the large grid sizes means that any theoretically important subgrid phenomena is modelled with a parameterised value, and its these values and how sensitive the model's are to the choice of these values that CPDN is testing. I think the function of the 'parameterised values' and how they make coarse grids ok for global climate modelling is the key point for this guy to understand. Let me know if my understanding is whacked... Cheers, Hasse
3) Message boards : climateprediction.net Science : CP too coarse a grid? (Message 7687) Posted 27 Jan 2005 by old_user18703 Post: Nothing like that :) Its from a guy whos expertise is in numerical analysis and who have doubts about the 'warnings' coming from these coarse climate models. I know enough science to be dangerous, but on this point I am clueless. So I would like to know how best to respond to a statement like that. Is there anyone that can give the question a NewScientist styled answer? :)
4) Message boards : climateprediction.net Science : CP too coarse a grid? (Message 7684) Posted 27 Jan 2005 by old_user18703 Post: How would you guys respond to the following statement? "The principles of a climate model are very similar to other fluid dynamics simulators. Now one of the great shortcomings of these simulators is that the cell size is generally too coarse to get reliable results as there simply isn't sufficient computing power available to run simulators with smaller grid sizes. Generally these simulators run on a much smaller scale than world climate simulators, and even then can't cope very well with turbulent flow or mixed phase flow. Now for someone to tell me I should trust a climate model with an incredibly coarse grid scale and far more complex fluid interactions well, understandably I have to suspend belief."