1. VIC Land surface model overview
Dennis P. Lettenmaier
Department of Civil Engineering
University of Washington
for presentation at
DOE ASM project meeting
San Francisco
December 14, 2007

2. VIC Modeling Framework
Features specific to Cold-Land Processes:
Two-layer energy balance snow model (Storck et al. 1999, Andreadis et al 2007)
Frozen soil/permafrost algorithm (Cherkauer et al. 1999, 2003)
Lakes and wetlands model (Bowling et al. 2004)
Blowing snow algorithm (Bowling et al. 2004)

3. VIC Snow Algorithm Storck et al. 1999 Bowling et al. 2004
Andreadis et al 2007

4. VIC Frozen Soil Algorithm
Cherkauer et al. 1999, 2003

5. Wetland Algorithm soil land surface runoff enters lake saturated
evaporation depletes soil moisture
lake recharges soil moisture
Bowling et al. 2004

6. VIC River Network Routing Model
Lohmann et. al. 1998

7. Snow Cover Extent Comparison
NOAA-NESDIS weekly snow charts
VIC

8. SWE, 1981
Thaw Depth, 1981

9. Fig. 9 Mean day of the year at when 5mm or less of SWE remained in the gridbox
(final melt day) for
Slater, A.G., T.J. Bohn, J.L. McCreight, M.C. Serreze, and D.P. Lettenmaier, 2007:
A Multi-Model Simulation of Pan-Arctic Hydrology, J. Geophys. Res. (accepted).

10. Lena at Kusur (Drainage Area: 2,430,000 km2)

11. Yenisey at Igarka (Drainage Area: 2,440,000 km2)

12. Digital river networks for the pan-Arctic drainage basins at the 100 km resolution, showing the watershed boundaries of the Lena, Yenisei, Ob, and Mackenzie.
A routing scheme [Lohmann et al., 1996; 1998] was run offline using daily VIC surface and subsurface runoff as inputs to obtain simulated streamflows at the outlets of selected study basins.
Eleven Regions were calibrated separately (not including Greenland)
Calibration was focused on matching the shape of the monthly hydrograph and annual runoff.
Parameter transfer to un-gauged basins was based on the hydro-climatology of the region.

13. WRF Software Architecture
WRF system components
Initialization
WRF-Var
Obs Data,
Analyses,
Forecast
Dynamics Solvers
ARW Solver
NMM Solver …
Standard Physics Interface
Physics Packages
Top-level Control,
Memory Management, Nesting,
Parallelism, External APIs
Post processors, Verification
Model coupling API enabling WRF to be coupled with other models such as ocean, and land models.
WRF Software Architecture
Hierarchical organization
Multiple dynamical cores
Plug compatible physics
Abstract interfaces (APIs) to external packages
Performance-portable
Skamarock, W. C., J. B. Klemp, J. Dudhia, D. O. Gill, D. M. Barker, W. Wang and J. G. Powers, 2005: A Description of the Advanced Research WRF Version 2. Technical Note, NCAR/TN–468+STR.

14. Model Coupling subroutinization Componentization sequential concurrent
( )
subroutinization
Componentization
(maintains the component codes in close
to their original forms)
( difficult to integrate with components
developed independently by other groups )
sequential
concurrent
(Two-way coupling)
(One-way coupling)
For model coupling the API may be implemented using packages such as the Model Coupling Toolkit (MCT) or The Model Coupling Environment Library (MCEL)
MCEL
MCT
(Single processor)
(Parallel)

15. WRF I/O and Model Coupling API Subroutines
ext_pkg_ioinit
ext_pkg_ioexit
ext_pkg_inquiry
ext_pkg_open_for_read
ext_pkg_open_for_read_begin
ext_pkg_open_for_read_commit
ext_pkg_open_for_write
ext_pkg_open_for_write_begin
ext_pkg_open_for_write_commit
ext_pkg_inquire_opened
ext_pkg_open_for_update
ext_pkg_ioclose
ext_pkg_read_field
ext_pkg_write_field
ext_pkg_get_next_var
ext_pkg_end_of_frame
ext_pkg_iosync
ext_pkg_inquire_filename
ext_pkg_get_var_info
ext_pkg_set_time
ext_pkg_get_next_time
ext_pkg_get_var_ti_type set of routines
ext_pkg_put_var_ti_type set of routines
ext_pkg_get_var_td_type set of routines
ext_pkg_put_var_td_type set of routines
ext_pkg_get_dom_ti_type set of routines
ext_pkg_put_dom_ti_type set of routines
ext_pkg_get_dom_td_type set of routines
ext_pkg_put_dom_td_type set of routines
ext_pkg_warning_string
ext_pkg_error_string