Sensitivity Study:

Computer Architecture and Convective Parameterization

Three 1-month simulations are compared. The simulations are carried out with MM5 and differ in one of three ways: (1) alternative convective parameterization, (2) different machine architecture, or (3) both (1) and (2). The simulations are labeled as follows. MM5-3.6.1 is run at Argonne National Lab (MMANL1, MMANL2) on their Jazz teraflop computer, which is a 350 node cluster of INTEL processors. MM5-3.6.0 is run at NCAR (MMISU1, MMISU2) on blackforest, a teraflop computer with 293 IBM POWER3 processors.

A list of changes between MM5-3.6.0 and MM5-3.6.1 is found within the NCAR/MMM MM5 support web pages. Although MM5-3.6.1 incorporates changes in how Noah LSM processes sea-ice and in components of the Reisner moist physics parameterization, none of the changes directly influence the results below.

The results are organized into tables such that computer architecture is identical for results presented along table rows and convective schemes are identical for results presented in columns.

  Grell Convective Parameterization Kain-Fritsch Convective Parameterization
Jazz at ANL MMANL1 July 1986 precipitation MMANL2 July 1986 precipitation
Blackforest at NCAR MMISU1 July 1986 precipitation MMISU2 July 1986 precipitation