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A New Site for Global Climate Calculations

The "A" tower of the Mesa Lab is buzzing. Upstairs, researchers are putting together a new climate system model (CSM). Downstairs, the Scientific Computing Division has assembled a suite of networked machines that will give life to simulations from the CSM and other sophisticated global models.

It's called the Climate System Laboratory (CSL). According to SCD director Bill Buzbee, it is one of only a small number of facilities in the world dedicated from day one to extensive global climate simulations. "That's the whole point. These kinds of projects often don't have adequate computing resources."

The CSL is serving much more than the CSM. The latter is among 11 projects that were approved for the CSL's first full year of operation, fiscal 1996.

"Several years ago it had become clear that the U.S. Global Change Research Program [USGCRP] was going to need substantial amounts of computing," says Bill. So in 1994, NSF and NCAR agreed to create an accelerated computing environment (ACE) for use by USGCRP scientists. Substantial support came from the NSF High Performance Computing and Communications (HPCC) program. The CSL was incorporated into ACE this summer with final approval by the National Science Board and $7.5 million of new funds from the USGCRP.

The first building block of the CSL was a CRAY Y-MP2 installed on the mesa for the Model Evaluation Consortium for Climate Assessment (MECCA) several years back. It was later replaced by four other Cray machines (see diagram).

"We have a respectable amount of computing power in place," says Bill, "and it is allocated to a variety of USGCRP projects." At present, the CSM is allocated about half of the CSL's total capacity of 10,000 to 11,000 equivalent Y-MP processor hours per month.

Among the outside grantees making use of the CSL:

  • John Kutzbach (University of Wisconsin-Madison), studying synchronous coupling schemes in paleoclimate simulation

  • Bert Semtner (Naval Postgraduate School), high-resolution simulations of global ocean ice

  • Michael Schlesinger (University of Illinois at Urbana-Champaign), greenhouse-based climate change scenarios

    The facility is open to all investigators funded or supported by U.S. universities and federal or other not-for-profit labs. The emphasis is on large and interdisciplinary teams addressing broadly posed questions that require dedicated supercomputing resources. This might include multiple 100-year runs of coupled climate models or very large model ensembles studying seasonal-to-interannual climate predictability.

    The CSL is still growing. A procurement cycle for new hardware is under way and should conclude early next year. The lab's capacity in gigaflops is expected to double or even quadruple in the next year or two. However, the plan is not for more studies--it's for bigger studies that can leverage the power of the CSL and its dedicated status. --BH

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    Edited by Bob Henson, bhenson@ucar.edu
    Last revised: Thu Mar 30 10:56:48 MST 2000