WRF4DVAR
WRF4DVAR: The 4-dimensional component of WRF-Var.
Reference
Huang, X.-Y., Q. Xiao, W. Huang, D. M Barker, J. Michalakes, J. Bray, Z. Ma, Y.-R. Guo, H.-C. Lin, and Y.-H. Kuo, 2006. Preliminary results of WRF 4D-Var. WRF users’ workshop, Boulder, Colorado, 19-22 June 2006. [1]
Barker, D. M., Guo, Y., Huang, W., Huang, H., Rizvi, S., Xiao, Q., Lee, M. S., 2005: WRF-VAR - A unified 3/4D-Var data assimilation system for WRF. 6th WRF/15th MM5 Users' Workshop, 10.1.
Huang, X., Xiao, Q., Huang, W., Barker, D. M., Kuo, Y., Michalakes, J., Ma, Z., 2005: The Weather Research and Forecasting model based 4-dimensional variational data assimilation system. 6th WRF/15th MM5 Users' Workshop.
Xiao, Q., Ma, Z., Huang, W., Huang, X., Barker, D., Kuo, Y., Michalakes, J., 2005: Development of the WRF tangent linear and adjoint models: Nonlinear and linear evolution of the initial perturbations and adjoint sensitivity analysis at high-southern latitudes. 6th WRF/15th MM5 Users' Workshop.
The recent presentations
Preliminary results of WRF 4D-Var. Talk. WRF users workshop, Boulder, Colorado, 19-22 June 2006. [2]
Meeting memos
Major svn commit notes
- 09/19/2006. svn 1623. John Michalak's updated RSL_LITE and related files committed by Xin Zhang.
- 08/23/2006. svn 1551. Yongrun's updated wrf_io.F90 by Hans Huang.
- 08/08/2006. svn 1512. Tl and AD obs operators for GPS PW, GeoAMV and PolarAMV by Hans Huang.
- 07/25/2006. svn 1436. Merge of John M's parallel code to the 4dvar branch by Xin Zhang.
- 07/21/2006. svn 1417. Modifications to arch-files and modifications for g95 options by Xin Zhang.
- 07/20/2006. svn 1412. Bug fixes and cv5-related updates by Hans Huang.
- 07/10/2006. The 4dvar branch has been moved from cvs to svn. To get started with svn, contact John Bray first.
Development notes
- The only obs type which cannot be handled in 4dvar is SSMI (in the current code, SSMI has a different coding structure in get_innov to all other obs types).
Work Plans
AFWA 2007 4D-Var work plan
| Priority | high | medium | high | high | low | low | |
| Multi-inc | J_lbc | Optimize | Met. test | convection | A2C | Sum | |
| Dale | (0.25) | 0.15 | 0.15 | ||||
| Hans | 0.1 | 0.1 | 0.1 | 0.5 | 0.80 | ||
| PS-I | 0.2 | 0.20 | |||||
| CSU | (0.25) | 0.2 | 0.20 | ||||
| Qingnong | 0.3 | 0.30 | |||||
| Jimy | 0.1 | 0.10 | |||||
| John M | 0.1 | 0.10 | |||||
| Tom | 0.4 | 0.40 | |||||
| Xin | 0.25 | 0.25 | 0.25 | 0.75 | |||
| Sum | 0.35 | 0.35 | 0.85 | 0.7 | 0.4 | 0.15 | 2.80 |
| (0.25) | (0.25) | (0.50) |
Multi-incremental formulation (Zhang 0.25 FTE + Huang 0.1 FTE)
Two new programs (may combined to one executable) will be coded first: 1) nup - interpolate from fine resolution to coarse resolution; 2) nup_inv - interpolate from coarse resolution to fine resolution.
Extend WRF 4D-Var version 2 system with the multi-incremental capability using nup and nup_inv.
Period: 1 March – 31 May 2007
Optimization (Henderson 0.4 FTE + Zhang 0.25 FTE + Michalakes 0.1 FTE + Huang 0.1 FTE)
General support for WRF 4D-Var parallelization (Michalakes).
Period: 1 March 2007 – 31 January 2008
Make an option of wrfplus using more memory to reduce re-computations. The first working version will be ready for testing before May. The final version will be ready for testing before September. The goal is to reduce the current 4dvar wall clock time by 50% (Henderson).
Period: 1 March – 31 August 2007
Reduce nonlinear re-computations of the basic states in the tangent linear and adjoint integrations. The goal is to reduce the current 4D-Var wall clock time by 50% (Zhang and Huang).
Period: 1 June – 31 August 2007
(We are arranging a subcontract with CSU to provide additional resources for preconditioning and radiances. The former will benefit WRF-Var in general, and may reduce the 4D-Var computation time significantly.)
Meteorological tests (Huang 0.5 FTE + PS-I 0.2 FTE (+ DATC effort: Barker )
Make a 45 km 4D-Var configuration on the AFWA 15 km domain. Collect observations for one or two selected cases (a case here should cover at least a few days). Make the configuration as close as possible to the AFWA current operational system. Compare the 4D-Var results with 3D-Var and make necessary tuning.
Make a 15/45 km 4D-Var configuration over the same domain and cases. Run the multi-incremental (15-km outer loop and 45-km inner loop) formulation and compare the results with the 15 km 3D-Var.
Provide a pre-operational setup to DATC for pre-operational tests. Support and interact with DATC colleagues during the pre-operational tests.
Experiment with different domain sizes and different resolutions to provide guidelines for possible changes of the pre-operational configuration.
Period: 1 March 2007 – 31 January 2008
Lateral boundary control (Zhang 0.25 FTE + Huang 0.1 FTE)
Study different formulations for lateral boundary control used by limited area data assimilation systems. Code the selected formulation and start the initial tests. Testing may continue to next year.
Period: 1 March 2007 – 31 January 2008
Convection (Xiao 0.3 FTE, Dudhia 0.1 FTE)
Investigate the current available convection schemes and select the most efficient one. If necessary, implement it in WRF and compare it with the commonly used scheme by WRF users.
Develop tangent linear and adjoint code of the selected convection scheme.Implement it in wrfplus.
Further testing will be carried out if an additional funding of 0.1 can be made available.
Period: 1 March – 31 August 2007
Using C-grid in Var (Barker 0.15 FTE)
Develop an option for WRF-Var to use C-grid and assess the impact on computational and meteorological aspects.
Period: 1 March – 31 August 2007
CRIEPI 4D-Var plan
Research Plan for the CRIEPI High-Resolution 4D-Var Project
Jenny Sun and Yong-Run Guo
We plan to examine the capability of WRF 4D-Var on convective-scale radar data assimilation with a 12/4 km nested domain using the IHOP June 12-13 squall line case. The study will be first performed with OSSE and then real data. The following is a list of the tasks:
1. WRF 4DVar code test on the inner domain with a reduced resolution. The purpose is to make sure the code runs properly.
2. Conduct the control run: 12/4-km two-domain nested run, the initial and boundary conditions from NCEP AWIP 3-hourly analysis (data already collected and tested with WRF-WPS and WRF-real).
3. Generate simulated sounding data from control run and simulated NEXRAD OBS based on the real radar sites (every 15 min).
4. Generate BE for 3/4DVar: Interplate_stats from Sugimoto 4-km BE that was derived using the NMC method for his 3DVar radar data assimilation study.
5. Conduct WRF 4DVar experiments on the 4km domain. Evaluate the sensitivity of the DA and forecasts with respect to window length (15, 30, and 60 min)
6. Conduct real data experiments.
Hurricane 4D-Var plan
To be added by Qingnong.
A short summary
The 4DVAR system has been under extensive development since 2004. The development effort has been primarily supported by the Air Force Weather Agency (AFWA).
The unified WRF-based 3/4DVAR system is named WRF-Var which includes the WRF model and WRF-3DVAR as its basic components. Its prototype will be ready in 2005 and its basic version should be constructed in 2006.
The WRF-Var follows closely the incremental 4DVAR formulation of Courtier et al. (1994), Veersé and Thépaut (1998), and Lorenc (2003).
The latest description of the 4d component of WRF-Var is Huang et. al. (2006).