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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. VIC Modeling Framework. Features specific to Cold-Land Processes:
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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
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)
VIC Snow Algorithm Storck et al. 1999 Bowling et al. 2004 Andreadis et al 2007
VIC Frozen Soil Algorithm Cherkauer et al. 1999, 2003
Wetland Algorithm soil saturated land surface runoff enters lake evaporation depletes soil moisture lake recharges soil moisture Bowling et al. 2004
VIC River Network Routing Model Lohmann et. al. 1998
Snow Cover Extent Comparison NOAA-NESDIS weekly snow charts VIC
SWE, 1981 Thaw Depth, 1981
Fig. 9 Mean day of the year at when 5mm or less of SWE remained in the gridbox (final melt day) for 1980-2001. 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).
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.
WRF Software Architecture Hierarchical organization Multiple dynamical cores Plug compatible physics Abstract interfaces (APIs) to external packages Performance-portable Top-level Control, Memory Management, Nesting, Parallelism, External APIs Dynamics Solvers ARW Solver NMM Solver … Dynamics Solvers Initialization Obs Data, Analyses, Forecast WRF-Var Standard Physics Interface Physics Packages Post processors, Verification WRF system components Model coupling API enabling WRF to be coupled with other models such as ocean, and land models. 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.
Model Coupling ( http://www.mmm.ucar.edu/wrf/WG2/software_2.0/index.html ) 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)
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