Chen, Xunlai, Shenzhen Meteorological Bureau, China, Center
for Analysis and Prediction of Storms, University of Oklahoma, USA, and Fanyou
Kong, Tuanjie Hou, Center for Analysis and Prediction of Storms, University of
Oklahoma, USA, and Qunfeng Zhen, Shenzhen Meteorological Bureau, China
The hourly assimilation
and prediction system (HAPS), a WRF-ARW based realtime storm-scale forecasting
system that was in operation in Shenzhen Meteorological Bureau since March
2010, has been verified for QPF during the 2011 summer months. The HAPS system
was developed collaboratively by Shenzhen Meteorological Bureau (SZMB), the
Center for Analysis and Prediction of Storms (CAPS) in the University of
Oklahoma, and the Shenzhen Institute of Advanced Technology (SIAT) of Chinese
Academy of Sciences. The HAPS system consists of an outer domain with 12-km
horizontal grid spacing and a one-way nested high-resolution domain at 4-km
grid spacing. Initial and boundary conditions for the 12-km horizontal
resolution grid are provided by the fine-resolution European Center for
Medium-Range Weather Forecasts (ECMWF) data initiated at 00 and 12 UTC each
day. The radial velocity and reflectivity data from 7 operational WSR-98D
radars in Guangdong province are analyzed into the initial condition at the
4-km domain using the ARPS 3DVAR and cloud analysis system every hour. Starting
in March 2011, the HAPS system has been run operationally, producing 48h
forecasts at 12-km domain twice daily and 12h forecasts at 4-km domain every
hour. The precipitation forecasts at both 12- and 4-km domains are verified
against rain gauge measurements from 1400 automatic weather stations (AWS) in
the region. Bias score (BIAS), root-mean-square error (RMSE), and equitable
threat scores (ETS) are computed during 2011 summer months to evaluate the
ability of the HAPS system on QPF. The results show that the HAPS system is
skillful throughout the entire forecast period. The skill deteriorates with
increasing threshold and forecast lead time. There is a systematic improvement
in terms of the accuracies and skill when the model horizontal resolution is
increased from 12km to 4km.