Hello, A new project on the LCRC cluster has been requested. Please forward the information on to the LCRC Allocation sub-committee. Applicant's name: Robert Jacob Applicant's institution: ANL Applicant's division: MCS Project Name: VegClimGeo Project title: Vegetation-climate feedback over geologic time. Associated funding: NFS Other Systems: Science: Before the Late Cretaceous, the tropics were drier and without an "everwet" rainforest biome. We have hypothesized that the Cretaceous/Cenozoic spread of tropical rainforests was enhanced by the evolution of the unique hydraulic properties of the flowering plants, or angiosperms. Our preliminary results using present-day climatic conditions imply that the high transpirational capacity of angiospermous plants increases moisture recycling by the land surface and thus increases the area of everwet rainforest. However, the impact of angiosperms on the hydrological cycle could be different in magnitude during Late Cretaceous/Early Cenozoic since the land-ocean configuration and atmospheric concentration of CO2 are also different. Here we propose quantifying the impact of plant physiology, land-ocean configuration, and atmospheric CO2 concentration on the seasonal distribution of tropical land precipitation and the size of the tropical rainforest. Project description: We plan to use the NCAR CAM3 (Community Atmosphere Model) coupled with CLM3.5 (Community Land Model) for this work. To explore the role of plant physiology, land-ocean configuration, and atmospheric CO2 concentration, CAM will be run at T42 resolution (~3ox3o) with a Slab Ocean Model and a Dynamic Vegetation Model. Since the Dynamic Vegetation Model describes the allocation, competition, and establishment of present-day ecosystems, we need to test and improve the model to be able to run it for our target period. CAM3/CLM3.5 has been parallelized with MPI and uses Fortran90 and C languages. A NetCDF library is also required for input/output. The dynamic vegetation model ~100 years to reach an equilibrium. We request fusion time to run 4 (CO2) * 4 (land-ocean configuration) * 4 (plant physiology) * 100 years for a scenario * 10 (testing) = 64000 years. We have measure the cost of this configuration on Hopper (an XT5) at NERSC with 2.4GHz AMD cores (similar to those on Fusion) and found it takes about 7 core-hours per year. We thus request 450000 core-hours Project URL: Requested allocation: 450000 Justification: The requester has used 0 hours of their initial startup project. In addition to approving an initial amount, please specify a Category and Subcategory for this project. For a list of the current selection of approved categories, please see: https://wiki.lcrc.anl.gov/wiki/Processes/Categories Once the Allocation committee has approved the project, please go to the Project Management page to create it: https://accounts.lcrc.anl.gov/projects.php Thank You, The LCRC Accounts System