yanhongyi
Member
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While the above procedure is useful, often for realtime applications it is better to run a so-called “cycling” forecast. In a WRF/WRFDA cycling system, rather than using WPS to generate the initial conditions for your assimilation/forecast, the output from a previous forecast is used. In this way, information from previous observations can be used to improve the current “first guess” of the atmosphere, ultimately resulting in an even better
analysis and forecast. The procedure for cycling is as follows:
1. For your initial forecast time (T1), generate initial and boundary conditions for WRF (wrfinput and wrfbdy_d01) via WPS (as described in Chapter
3 of this users guide) and real.exe (as described in Chapter 5 of this users guide)
2. Run WRFDA on this wrfinput to assimilate observations to produce a wrfvar_output file (a new, improved wrfinput)
3. Run da_update_bc.exe to update the WRF lateral boundary conditions file created in step 1 (wrfbdy_d01) to be consistent with the new wrfinput
file
4. Run wrf.exe to produce a WRF forecast (wrfout) for the next forecast time (T2)
5. Repeat step 1 for the next forecast time (T2) to produce initial and boundary conditions for WRF (wrfinput and wrfbdy_d01) via WPS and real.exe
6. Run da_update_bc.exe to update the lower boundary conditions of the WRF forecast file (wrfout) with data from the wrfinput file generated
in step 5.
7. Run WRFDA on this wrfout file to assimilate observations and produce a wrfvar_output file (a new, improved wrfinput for the next WRF forecast)
8. Run da_update_bc.exe again to update the WRF boundary conditions file created in step 5 (wrfbdy_d01) to be consistent with the new wrfinput
file
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The above content comes from WRFuserguide.
What I want to ask about this paragraph and description in the userguide is, for example, if I want to make a 12-hour cyclic forecast, then, in addition to using WPS to produce the wrfinput to directly run wrf, we should use the previous forecast file (wrfout) as the new initial field after assimilation.
But after I use WRFDA to assimilate the observations into the wrfout file, it is still in the format of the wrfout file. After naming it directly as wrfinput, the WRF cannot be successfully driven. What should I do?
While the above procedure is useful, often for realtime applications it is better to run a so-called “cycling” forecast. In a WRF/WRFDA cycling system, rather than using WPS to generate the initial conditions for your assimilation/forecast, the output from a previous forecast is used. In this way, information from previous observations can be used to improve the current “first guess” of the atmosphere, ultimately resulting in an even better
analysis and forecast. The procedure for cycling is as follows:
1. For your initial forecast time (T1), generate initial and boundary conditions for WRF (wrfinput and wrfbdy_d01) via WPS (as described in Chapter
3 of this users guide) and real.exe (as described in Chapter 5 of this users guide)
2. Run WRFDA on this wrfinput to assimilate observations to produce a wrfvar_output file (a new, improved wrfinput)
3. Run da_update_bc.exe to update the WRF lateral boundary conditions file created in step 1 (wrfbdy_d01) to be consistent with the new wrfinput
file
4. Run wrf.exe to produce a WRF forecast (wrfout) for the next forecast time (T2)
5. Repeat step 1 for the next forecast time (T2) to produce initial and boundary conditions for WRF (wrfinput and wrfbdy_d01) via WPS and real.exe
6. Run da_update_bc.exe to update the lower boundary conditions of the WRF forecast file (wrfout) with data from the wrfinput file generated
in step 5.
7. Run WRFDA on this wrfout file to assimilate observations and produce a wrfvar_output file (a new, improved wrfinput for the next WRF forecast)
8. Run da_update_bc.exe again to update the WRF boundary conditions file created in step 5 (wrfbdy_d01) to be consistent with the new wrfinput
file
==========================================================================================================================
The above content comes from WRFuserguide.
What I want to ask about this paragraph and description in the userguide is, for example, if I want to make a 12-hour cyclic forecast, then, in addition to using WPS to produce the wrfinput to directly run wrf, we should use the previous forecast file (wrfout) as the new initial field after assimilation.
But after I use WRFDA to assimilate the observations into the wrfout file, it is still in the format of the wrfout file. After naming it directly as wrfinput, the WRF cannot be successfully driven. What should I do?