CCM3 T170 Cloud and Precipitation Simulation

Introduction

Today's generation of climate models are typically run at T42 resolution, which translates to about a 3 degrees latitude-longitude finite difference grid at the equator. At this resolution, major geographical regions are entirely unaccounted for by the models. For example, the California Sierras slope linearly up to the Rockies, leaving out the Great Basin completely. With support from the DOE CCPP program and the Central Research Institute of Electric Power Industry (CRIEPI) in Tokyo, an experimental version of the NCAR CCM3 model was run at T170 resolution (512x256 gridpoints) where the solution was sampled hourly for an entire year. This is comparable to examining the solution as would be done in a global weather model.

The Research Effort

This simulation was conducted in connection with a collaborative scientific investigation of high-resolution global climate modeling. This project involved scientists and software engineers at both the National Center for Atmospheric Research and at the Central Research Institute of Electric Power Industry (CRIEPI) in Japan. Portions of the simulations required to produce this animation were conducted on a 128-processor SGI Origin 2000 computer system located at Los Alamos National Laboratory, and on an 8-processor NEC SX4 computer system in Tokyo. Because of the large computational demands, global climate models are typically run at a horizontal resolution that is four times courser than for the present study. The simulation used for the current animation nominally resolves features as small as 75 kilometers and is about 60 times more expensive than a typical climate model because of the increase in horizontal resolution.

TMQ (water vapor) is white and TOTPRCP (total precipitation) is orange. Early in the year, note the high levels of moisture over northern Australia - the Australian Monsoon. In mid-February cyclonic behavior may be observed in the Bay of Bengal.

Late in April the onset of the Indian monsoon season begins to appear, with large amounts of moisture moving upwards towards the Tibetan plateau.

As time passes, note the large streams of moisture flowing from the tropics into the northern latitudes. In mid-July there's some pronounced rotating behavior over Central America followed by a much stronger signature later in the month. Note the cyclone east of Madagascar in early October.