Evaluation of WRF and HadRM mesoscale climate simulations over the United States Pacific Northwest


Zhang, Y., Dulire, V., Mote, P.W., Salathé, E.P.  2009. Evaluation of WRF and HadRM mesoscale climate simulations over the United States Pacific Northwest. Journal of Climate 22(20):5511-5526, doi: 10.1175/2009JCLI2875.1.


This work compares the WRF (Weather Research and Forecasting) and HadRM (Hadley Centre Regional Model) simulations with the observed daily maximum and minimum temperature (Tmax and Tmin) and precipitation at HCN (Historical Climate Network) stations over the U.S. Pacific Northwest for 2003-2007. The WRF and HadRM runs were driven by the NCEP-DOE (Department of Energy) R-2 reanalysis data. The simulated Tmax in WRF and HadRM as well as in R-2 compares well with the observations. Predominantly cold biases of Tmax are noted in WRF and HadRM in spring and summer while in winter and fall more stations show warm biases especially in HadRM. Large cold biases of Tmax are noted in R-2 at all times. The simulated Tmin compares reasonably well with the observations although not as well as Tmax both in WRF and HadRM and in R-2. Warm biases of Tmin prevail in both model simulations while R-2 shows mainly cold biases. The R-2 data play a role in the model biases of Tmax although there are also clear indications of resolution-dependency. The model biases of Tmin originate mainly from the regional models. The temporal correlation between the simulated and observed daily precipitation is relatively low in WRF and HadRM and R-2. However, the correlation increases steadily for longer averaging times. With high resolution, improvement in model performance over R-2 is noted although the nested WRF domains also show the largest biases in winter and spring. Wet biases are evident in WRF while HadRM shows mainly dry biases.