On the eastern seaboard, East coast lows (ECLs) can lead to very high rainfall totals in short time periods.
We investigate the underlying physics of this observation by examining the impact of different physics
parameterizations on extreme precipitation in ECLs. A number of ECLs are simulated with the Weather
Research and Forecasting model, and we focus on the strongest simulated event here: the 2007 Newcastle
ECL. We examine the sensitivity of precipitation extremes to microphysical schemes, radiation schemes,
boundary and surface layer physics, and cumulus parameterizations. We show how the cumulus
parameterization, and to a lesser extent the boundary layer, can have a significant impact on the most
extreme precipitation accumulations on the sub-daily time scale. Extreme accumulations on daily and longer
time scales are less sensitive to the choice of physical parameterization. The most likely explanation for this
behaviour involves changes in moisture transport when different cumulus parameterizations and boundary
layer schemes are employed.
This page is maintaind by Jason Evans |
Last updated 31st January 2013