Bullock, Russell, Jerry Herwehe, Megan Mallard, and Tanya
Otte, US Environmental Protection Agency
Previous dynamical
downscaling techniques developed using WRF at 108- and 36-km resolution are
applied for further downscaling to 12-km resolution over the eastern United
States and southeastern Canada.
The previous work investigated both analysis nudging and spectral
nudging to constrain the WRF simulation.
This work investigates the adjustments to the nudging parameters
required for an optimum application at 12-km resolution. Lake surface temperatures for the
previous work were determined from 2.5-degree latitude/longitude resolved sea
surface temperature data and that technique is also applied here with the
results suggesting that a more realistic approach to estimating or simulating
lake surface temperatures is needed for 12-km resolution. Simulated surface-level temperature,
water vapor mixing ratio, and wind speed are compared to hourly observations
collected by the Meteorological Assimilation Data Ingest System (MADIS) to
demonstrate the improved accuracy of the 12-km downscaling results. Simulated precipitation is compared to
Multisensor Precipitation Estimator (MPE) data showing a general excess of
precipitation, especially in the southeast during summer.