Cray C90 upgrade to the Climate Simulation Laboratory

The Climate Simulation Laboratory began operation August 1, 1995. The primary computational resources were a Cray Y-MP/8I with 8 processors and a Cray J90 with 10 processors. To understand the sensitivity of climate models to various choices or parameters in physics, scientists need the ability to routinely complete century-long simulations of the climate. However, while the Y-MP/8I and the Cray J90 had sufficient computational power to support development of new models such as the Climate System Model, these machines did not have the power to promptly complete century-long simulations. For example, a Y-MP/8 dedicated to executing the CSM around the clock would take two months of wall clock time to simulate a single century. In the production environment of the CSL, the Y-MP/8I required one day of wall-clock time to simulate one year running the CSM; thus more than three months were required to simulate a century.

CSL productivity was enhanced dramatically in December 1996 when the Y-MP/8I, known as antero, was replaced by a Cray C90, also named antero, with 16 processors, 256 megawords of central memory, and a 512 megaword SSD. This new C90 provides better than a factor of four increase in computing power over its predecessor (the Y-MP/8I). In the CSL production environment, the CSM averages approximately 5.2 GFLOPS on the C90 and now simulates five years per day of wall-clock time, and less than one month is required to simulate a century.

The Cray C90 (antero) provides 10,400 CPU hours per month for CSL users.

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