ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Archive > Volume 43 Issue 12 > 2017,43(12):1461-1472. DOI:10.7519/j.issn.1000-0526.2017.12.002 Prev Next
Study on Initial Perturbation Construction Method for Regional Ensemble Forecast Based on Dynamical Downscaling
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Abstract:
Using Global Ensemble Forecast System (GEFS) data, a regional ensemble forecast system based on WRF model is constructed. Two initialization schemes are tested to form the initial states of regional ensemble (namely DRUC ensemble). One is the direct dynamical downscaling of GEFS initial states (namely DOWN ensemble), and the other is the overlaying the downscaled initial perturbations of GEFS onto the analysis of high resolution regional numerical weather prediction (NWP) system, named Beijing Rapid Update Cycle (BJRUC) system. Using the two methods, a series of ensemble forecast tests are conducted, and the results show that the smallscale components of DRUC perturbations grow more rapidly than those of DOWN perturbations. For shortterm forecast, the DOWN perturbations tend to underestimate the forecast error while the DRUC perturbation tends to identify where the forecast error is large and where the forecast error is small. Ensemble forecast verification shows that the DRUC ensemble has larger spread and smaller root mean square error than DOWN ensemble at short forecast lead time, and the probabilistic scores of DRUC are also better for shortterm forecast. Typical precipitation case study shows that DRUC ensemble can provide better probabilistic precipitation forecast than DOWN ensemble.
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Clc Number:
P456
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