Publications

Extreme precipitations and temperatures over the U.S. Pacific Northwest: A comparison between observations, reanalysis data and regional models

Citation

Dulire, V., Zhang, Y., Salathé, E.P.  2011. Extreme precipitations and temperatures over the U.S. Pacific Northwest: A comparison between observations, reanalysis data and regional models. Journal of Climate 24(7): 1950-1964, doi: 10.1175/2010JCLI3224.1.


Abstract

We examine extreme precipitation and temperature indices in the R2 reanalysis data and the nested WRF (Weather Research and Forecasting) and HadRM (Hadley Centre Regional Model) simulations at HCN (Historical Climatology Network) stations over the United States Pacific Northwest during 2003-2007. The WRF and HadRM simulations driven by the R2 reanalysis data represent the observed extreme precipitations reasonably well: correlation coefficients are high and statistically significant, and slopes are close to 1. The WRF Domain 3 with its highest resolution (~12 km) shows the best statistical performance when compared to the 36km WRF Domain 2 and 25km HadRM. The R2 reanalysis data represent the timing of rainbearing storms over the Pacific Northwest well; however, the reanalysis have the worst performance at simulating both extreme precipitation indices and extreme temperature indices when compared to the WRF and HadRM simulations. Improvement in the extreme temperature indices is also noted for WRF and HadRM simulations when compared to the R2 reanalysis data. These results suggest that the R2 reanalysis data, and by extension global climate model simulations, are not sufficient for examining extreme precipitations and temperatures due to their coarse resolutions. Nevertheless, the largescale forcing for extreme events is represented by the reanalysis so that these events may be simulated in the regional models.