Posts by old_user98682

1) Message boards : climateprediction.net Science : Regional attribution models - ensemble type? (Message 48813) Posted 16 Apr 2014 by old_user98682 Post: Good observation Iain, as the equal probability basis suggests that an initial condition ensemble is being used since small perturbations reflect the uncertainty in measuring the state of the atmosphere and ocean. Then the impact of chaos theory results in a much broader spread of final outcomes than would be expected given the small spread of initial conditions. I too ran simulations for the original CPDN slab model experiment to generate a probability distribution of temperature, which involved both initial condition and model parameter ensembles, and also recall not really understanding how the parameter selection scheme worked, so you weren't alone in being in the dark!
2) Message boards : climateprediction.net Science : Regional attribution models - ensemble type? (Message 48791) Posted 14 Apr 2014 by old_user98682 Post: Thanks Iain for the explanation regarding my question about whether the Regional Attribution model is deterministic - the variation across CPU and OS makes sense given the different run-time libraries used. As for the second part of my question, the reason why I asked what type of ensemble is used in the attribution experiments is that for a deterministic model, using exactly the same model parameters and initial conditions will result in precisely the same outcome (subject to the CPU and OS variance that you've explained), which would hardly be useful for estimating the likelihood of extreme events! My guess is that an initial condition ensemble is used (with small perturbations to reflect the uncertainty in ocean and atmospheric observations), since altering model parameters would change the representation of the physics, but I'm curious as to whether this is indeed the case.
3) Message boards : climateprediction.net Science : Regional attribution models - ensemble type? (Message 48783) Posted 13 Apr 2014 by old_user98682 Post: Greetings all, I assume that the regional attribution model used in the UK winter floods and ANZ heatwave & drought experiments is deterministic (i.e. two simulations started with exactly the same initial conditions will follow the same trajectory)? If so, what type of ensemble is being used to estimate the probability of extreme events? Is it an initial conditions ensemble or are model parameters being perturbed? Thank you for any clarification, as I couldn't find an answer to this question in the experiment webpages.
4) Questions and Answers : Getting started : No work available for ANZ project? (Message 48613) Posted 29 Mar 2014 by old_user98682 Post: Hi Les, Thanks very much for your reply, which magically seems to have done the trick as my computer just downloaded the models! I've made my computer visible to facilitate any future troubleshooting but everything now seems to be working fine. Thanks again for your help. Best Regards, Nick
5) Questions and Answers : Getting started : No work available for ANZ project? (Message 48610) Posted 29 Mar 2014 by old_user98682 Post: Greetings all, Following a long layoff from CPDN (and BOINC), today I downloaded the BOINC 7.2.42 manager to run the Weather @ Home Austrlia and New Zealand project. However, despite selecting this project on my CPDN preference page and the Server Status webpage showing that there are over 8,000 work units read to send, the BOINC manager is reporting that "no work available to process". Can anyone help me resolve this issue? Thanks, Nick