首页|Statistical Downscaling Based on Dynamically Downscaled Predictors: Application to Monthly Precipitation in Sweden

Statistical Downscaling Based on Dynamically Downscaled Predictors: Application to Monthly Precipitation in Sweden

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A prerequisite of a successful statistical downscaling is that large-scale predictors simulated by the General Circulation Model (GCM) must be realistic. It is assumed here that features smaller than the GCM resolution are important in determining the realism of the large-scale predictors. It is tested whether a three-step method can improve conventional one-step statistical downscaling. The method uses predictors that are upscaled from a dynamical downscaling instead of predictors taken directly from a GCM simulation. The method is applied to downscaling of monthly precipitation in Sweden. The statistical model used is a multiple regression model that uses indices of large-scale atmospheric circulation and 850-hPa specific humidity as predictors. Data from two GCMs (HadCM2 and ECHAM4) and two RCM experiments of the Rossby Centre model (RCA1) driven by the GCMs are used. It is found that upscaled RCA1 predictors capture the seasonal cycle better than those from the GCMs, and hence increase the reliability of the downscaled precipitation. However, there are only slight improvements in the simulation of the seasonal cycle of downscaled precipitation. Due to the cost of the method and the limited improvements in the downscaling results, the three-step method is not justified to replace the one-step method for downscaling of Swedish precipitation.

downscalingmultiple regressionatmospheric circulation indicesmonthly precipitationSweden

Cecilia HELLSTROM、Deliang CHEN

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Earth Sciences Centre, Gothenburg University, Gothenburg, Sweden

National Climate Center, China Meteorological Administration, Beijing, China

科技部资助项目中国科学院资助项目MISTRA and SMHI

2003

大气科学进展(英文版)
中国科学院大气物理研究所

大气科学进展(英文版)

CSCDSCI
影响因子:0.741
ISSN:0256-1530
年,卷(期):2003.20(6)
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