Skip to main content
U.S. flag

An official website of the United States government

Dot Gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

The Impact of Different WRF Model Physical Parameterizations and Their Interactions On Warm Season MCS Rainfall


In recent years, a mixed-physics ensemble approach has been investigated as a method to better predict mesoscale convective system ( MCS) rainfall. For both mixed-physics ensemble design and interpretation, knowledge of the general impact of various physical schemes and their interactions on warm season MCS rainfall forecasts would be useful. Adopting the newly emerging Weather Research and Forecasting ( WRF) model for this purpose would further emphasize such benefits. To pursue this goal, a matrix of 18 WRF model configurations, created using different physical scheme combinations, was run with 12-km grid spacing for eight International H2O Project ( IHOP) MCS cases. For each case, three different treatments of convection, three different microphysical schemes, and two different planetary boundary layer schemes were used. Sensitivity to physics changes was determined using the correspondence ratio and the squared correlation coefficient. The factor separation method was also used to quantify in detail the impacts of the variation of two different physical schemes and their interaction on the simulated rainfall. Skill score measures averaged over all eight cases for all 18 configurations indicated that no one configuration was obviously best at all times and thresholds. The greatest variability in forecasts was found to come from changes in the choice of convective scheme, although notable impacts also occurred from changes in the microphysics and planetary boundary layer ( PBL) schemes. Specifically, changes in convective treatment notably impacted the forecast of system average rain rate, while forecasts of total domain rain volume were influenced by choices of microphysics and convective treatment. The impact of interactions ( synergy) of different physical schemes, although occasionally of comparable magnitude to the impacts from changing one scheme alone ( compared to a control run), varied greatly among cases and over time, and was typically not statistically significant.

Article / Publication Data
Available Metadata
Fiscal Year
Publication Name
Weather and Forecasting
Published On
December 01, 2005
Publisher Name
Amer Meteorological Soc
Print Volume
Print Number
Submitted On
May 16, 2005


Not available


Authors who have authored or contributed to this publication.