Ensemble Forecast Experiment on Precipitation in Summer by CWRF Numeric Model

Using CWRF numeric model developedby ISWS/UIUC with GFS real forecast data which has 4 times per day and 0.5°×0.5° SST real-time analysis data from NCEP as initial and boundary conditions,adopting 8 group different parameterization schemes from microphysics,cumulusconvection,boundary layer and radiation parameterization,an ensemble forecast system which has 32 members was established.Also,the time-variation integration forecast schemeand dynamic weight allocation integration forecast schemewere designed.Based on above forecast system,we experimented on 120 hours real time ensemble forecast.The result showed that CWRF model has good forecast ability for precipitationin China.In short term forecast,the ensemble member is more sensitive to cumulusparameterization.Dynamic weight allocation integration forecast schemewhich considered forecast errors can reflectmodel′s forecast capacity in different physical parameterizations,location,and forecast period conditions,on the whole,it has better forecast ability than time-variation integration forecast schemeand any ensemble member.