Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Jong Kim Project Name: POPAD Division: MCS Project title: Adjoint Development of POP Ocean Model for Climate Modeling Applications Associated funding: DOE CCPP Program: IMPACTS Project Other Systems: Science: The main purpose of the DOE IMPACTS project is to quantify the risks of abrupt climate change during the 21st century. The basic research effort is focused on assessing the near-term prospects for abrupt climate change on decadal time scales. The investigation is based on the NCAR-DOE Community Climate System Model (CCSM). It involves various types of new developments to examine several potentially significant sources of abrupt climate change. The role of ANL is to enhance the CCSM POP Ocean model with tangent linear and adjoint modeling (TLM/ADM) capabilities to allow a detail sensitivity analysis of the POP ocean model. Project description: In realizing the importance of the meridional overturning circulation (MOC) to the global climate variations, an essential element is to fully understand the MOC sensitivity to various forcing variables and modeling parameters. However, there are significant uncertainties in the model configurations such as mixing parameter values and initial and boundary conditions. More systematic computational tools are desirable for robust and efficient modeling experiments. Unfortunately, the computational costs to run large-scale sensitivity studies with conventional approaches such as ensemble approaches or perturbed numerical difference are prohibitively high. As an alternative to the conventional approaches, automatic differentiation (AD) has been applied to enhance the POP ocean model with the derivative computations of the TLM/ADM methods. In the previous year, major source codes of the AD-based POP TLM/ADM methods were successfully implemented and optimized f or short runs of a low resolution model. We plan to continue further applications of the new codes for the sensitivity studies of POP modeling variables with regard to global ocean circulations. In FY2013, the experiments for longer run simulations of the POP ocean models will be mainly performed with 1 degree resolution for the MPI-based parallel run test. It requires to run various types of the CCSM coupled and TLM/ADM simulations. Generally, the multi-decadal integrations of a coupled CCSM system for low resolution problems require a single computational time on the 8 cores of the fusion. The POP TLM/ADM runs take about 10 times of the computational cost compared to the forward POP integrations. Mainly written in Fortran 90, each of modeling component of the CCSM modeling system requires a C compiler and the MPI library to run with a link with Perl script. Project URL: Current FY Hours Used: undetermined amount New FY Requested allocation: 8000 Q1: 2000 Q2: 2000 Q3: 2000 Q4: 2000 Justification: Thank You, The LCRC Accounts System