Hello, A change in allocation has been requested: Requester: jacob (Robert Jacob) Project: foam Title: Global Climate Modeling with the Fast Ocean Atmosphere Model Description: Our major objective is to test the application of the Ensemble Kalman Filter to FOAM for tuning model parameters in a coupled mode. In spite of decades of effort, coupled ocean-atmosphere general circulation models (OAGCM) like FOAM still suffer from significant model biases, notably in the tropics. A significant part of these biases is caused by uncertainties in the model parameters. So far, however, parameter tuning in OAGCMs remains rudimentary. We will use our time to develop a strategy of a systematic parameter optimization in an OAGCM. In Fy11, we have successfully implemented coupled EnKF data assimilation system on FOAM on FUSION. Next, we use this system to develop an adaptive coupled ensemble Kalman Filter system (AcEnKF) for a simultaneous estimation of model parameter and state. We will also explore different assimilation techniques to search for an effective method of parameter optimization in OAGCMs. Given the time, we can also study coupled dynamics relevant to parameter optimization in the tropical climate system for both the climatology and climate variability. Based on our previous work, we found that the data assimilation results are very sensitive to some parameters of the ensemble package. We need to do some tests to find the optimal parameters for the ensemble package first. Then we will move on to parameter estimation. For this request, we'll assume fifty members will be used for each experiment. We expect about 150 different sets of parameters and initial conditions. Each integration should take 30 years such that the total model years are: Parameter estimation experiments: 50x30x150 =225,000 years. We will also test a new Ensemble Adjustment Kalman Filter scheme that we developed recently. In this scheme, ensemble members will be randomly grouped into subgroups at each assimilation time. Simple model study shows that this scheme reduces outliers and therefore reduces analysis error. We will be testing this scheme in FOAM. We will test 60 experiments, each of 30 model years. This gives an additional model years: Random grouping EAKF experiments: 50x30x60 =90,000 years We have measured a cost of 2.133 core-hours/simulated year leading to a request of 640000 core-hours. This gives us the total hours for model experiments as Total cpu for experiments: (225000+90,000)yearsx2.133 = 692K core-hours With some minor time for testing, we request a total of 700k core-hours for FY12. Current: undetermined amount Justification: We have measured a cost of 2.133 core-hours/simulated year. The 210 total experiments are independent and can be run simultaneously. FOAM is very scalable between 4 and 64 processors. We choose to run on 16 or 32 because the additional parallelism comes from the ensemble members. Requested: 300000 A specific reason has been given: We originally requested 600K and were awarded 300K. We are thus asking for another 300K. This needs to be approved and the final allocation amount decided upon. Thank You, The LCRC Accounts System