Parallel Ocean Program

Parallel Ocean Program. It is a high-resolution, global ocean circulation model developed for use on massively parallel supercomputer architectures. The model is a cornerstone of the Community Earth System Model and is widely used for studying climate dynamics, oceanography, and geophysical fluid dynamics. Its development has been led primarily by researchers at the Los Alamos National Laboratory in collaboration with the broader National Center for Atmospheric Research community.

Overview

The Parallel Ocean Program represents a significant advancement in computational fluid dynamics applied to the Earth's oceans. It is designed to simulate the complex three-dimensional flow of the global ocean by solving the primitive equations on a structured grid. The model's architecture allows it to leverage the processing power of modern high-performance computing systems, such as those at the Oak Ridge National Laboratory and the Argonne National Laboratory. This capability enables simulations that resolve critical features like the Gulf Stream, the Antarctic Circumpolar Current, and ocean eddies, which are essential for accurate climate prediction.

Development and Architecture

The development of the Parallel Ocean Program began in the 1990s, building upon earlier ocean models like the Bryan-Cox-Semtner model. A key innovation was its use of a parallel programming paradigm, specifically the Message Passing Interface, to distribute computations across thousands of processors. The core numerical scheme is based on the finite difference method applied to a generalized orthogonal latitude-longitude grid, though versions also support alternative grids like the POP grid. This design was heavily influenced by work at institutions like the Massachusetts Institute of Technology and the University of California, Los Angeles. The model's scalability has been demonstrated on systems such as the IBM Blue Gene and Cray XC series.

Scientific Applications and Capabilities

Scientists employ the Parallel Ocean Program for a vast array of research, from investigating paleoclimate during the Last Glacial Maximum to projecting future changes under scenarios from the Intergovernmental Panel on Climate Change. It is integral to major model intercomparison projects like the Coupled Model Intercomparison Project and the Ocean Model Intercomparison Project. The model can simulate key processes including thermohaline circulation, ocean acidification, sea ice formation in the Arctic Ocean, and biogeochemical cycles. Its outputs are crucial for understanding phenomena such as El Niño-Southern Oscillation, the Atlantic meridional overturning circulation, and sea level rise.

Model Components and Features

The Parallel Ocean Program comprises several interconnected components that represent different physical processes. The dynamical core solves the Navier-Stokes equations with approximations suitable for large-scale geophysical fluid dynamics. It includes sophisticated parameterizations for ocean turbulence, subgrid-scale mixing, and air-sea fluxes. The model incorporates a sea ice model, often the CICE model, to simulate the cryosphere. Additional modules can be coupled for marine ecosystem studies, carbon cycle modeling, and tracer transport. Features like partial cell topography at the ocean floor and advanced advection schemes for properties like salinity and temperature enhance its realism.

Community and Usage

The Parallel Ocean Program is maintained and distributed as part of the Community Earth System Model framework, managed by the National Center for Atmospheric Research. Its user community spans major research centers worldwide, including the Max Planck Institute for Meteorology, the Met Office, the Japan Agency for Marine-Earth Science and Technology, and the Commonwealth Scientific and Industrial Research Organisation. The model is used for operational ocean forecasting at institutions like the Naval Research Laboratory and in foundational climate assessments for the United Nations Framework Convention on Climate Change. Extensive documentation, support, and model data are available through the Earth System Grid Federation.

Category:Climate modeling Category:Oceanography Category:Scientific simulation software