Antarctic Mesoscale Prediction System (AMPS) on pegasus
||Pegasus is a 71-node IBM Cluster
1350 computer. It provides the production and development environments
for the Antarctic Mesoscale Prediction System (AMPS). The production
runs on the pegasus cluster produce twice-daily experimental real-time
forecasts that support flight operations at McMurdo Station, Antarctica
and scientific activities around the continent.
The pegasus cluster system became the sole production system at NCAR
for the Antarctic Mesoscale Prediction System (AMPS) in December 2005.
Pegasus was the second supercomputer-class Linux cluster deployed by
CISL. The other Linux cluster, lightning, provides backup service
if necessary to greatly reduce the potential for missed forecasts.
Reliability has been excellent. AMPS is an experimental mesoscale
numerical weather prediction (NWP) system providing support to
forecasting for the United States Antarctic Program (USAP). For the
USAP, AMPS provides forecasters with model guidance at the highest
spatial and temporal resolution available for Antarctica. To
researchers in Antarctic meteorology and climatology, AMPS offers
a vehicle for process and event studies, a platform to test
parameterizations in the polar regions, and a long-term database
of high-resolution numerical output. AMPS also provides Antarctic
NWP support for other nations.
This computing effort advances two of NCAR's strategic objectives:
"Improving prediction of weather, climate, and other atmospheric phenomena"
and "Supporting and conducting regional-scale investigations of climate and
weather." To support flight operations and forecasters in Antarctica, the
pegasus cluster runs the MM5 mesoscale weather model on a set of 60-km
(Southern Ocean), 20-km (Antarctica), 6.67-km (western Ross Sea, South
Pole, Antarctic Peninsula), and 2.3-km (Ross Island) grids twice daily,
a significant improvement over the previous 90, 30, 10, and 3.3-km grids.
AMPS employs the Polar MM5 weather model, a version of the MM5 developed
primarily at the Byrd Polar Research Center. The Polar MM5 contains
a number of modifications to better represent processes in the polar
In FY 2006, pegasus' capacity allowed the development of a new
capability: on-demand implementation of nested one-way,
higher-resolution grids. This allows enhanced resolution over
areas of new Antarctic activity without interfering with the basic
forecast production of AMPS. The capability was enlisted three times
in the 2005-2006 field season. This capability is nimble and has the
potential to offer especially valuable assistance to emergency
operations on the ice.
The capacity of pegasus allows AMPS to run two mesoscale models,
both the MM5 and WRF. This has been important, allowing forecasters to
transition from the older MM5 to the newer WRF and to begin understanding
its performance. In addition, it provides time for the model developers
to create and implement a polar version of WRF, while the existing polar
MM5 remains available. This transition will continue through FY 2007.
Under sponsorship from the NSF Office of Polar Programs and in
collaboration with the Byrd Polar Research Center of the Ohio State
University, these real-time AMPS forecasts have been tailored to the
needs of the forecasters at McMurdo Station, Antarctica. Additional
information about the AMPS program is available from the
AMPS web page.