VIC Land surface model overview

Dennis P. Lettenmaier

Department of Civil EngineeringUniversity of Washington

for presentation at

DOE ASM project meeting

San FranciscoDecember 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

soilsaturated

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).

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

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

•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.

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.

Initialization

WRF-Var

Obs Data,Analyses,Forecast

Dynamics SolversDynamics Solvers

ARW SolverNMM Solver

…

Standard Physics Interface

Physics Packages

Top-level Control,Memory Management, Nesting,

Parallelism, External APIs

Post processors, Verification

WRF system components

WRF Software Architecture

– Hierarchical organization

– Multiple dynamical cores

– Plug compatible physics

– Abstract interfaces (APIs) to external packages

– Performance-portable

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.

For model coupling the API may be implemented using packages such as the Model Coupling Toolkit (MCT) or The Model Coupling Environment Library (MCEL)

Model Coupling

Componentization(maintains the component codes in close

to their original forms)

subroutinization( difficult to integrate with components

developed independently by other groups )

concurrent sequential(One-way coupling) (Two-way coupling)

MCTMCEL (Single processor) (Parallel)

( http://www.mmm.ucar.edu/wrf/WG2/software_2.0/index.html )

WRF I/O and Model Coupling API Subroutines

ext_pkg_end_of_frameext_pkg_iosyncext_pkg_inquire_filenameext_pkg_get_var_infoext_pkg_set_timeext_pkg_get_next_timeext_pkg_get_var_ti_type set of routinesext_pkg_put_var_ti_type set of routinesext_pkg_get_var_td_type set of routinesext_pkg_put_var_td_type set of routinesext_pkg_get_dom_ti_type set of routinesext_pkg_put_dom_ti_type set of routines

ext_pkg_get_dom_td_type set of routinesext_pkg_put_dom_td_type set of routines

ext_pkg_warning_stringext_pkg_error_string

ext_pkg_ioinitext_pkg_ioexit ext_pkg_inquiry ext_pkg_open_for_read ext_pkg_open_for_read_beginext_pkg_open_for_read_commitext_pkg_open_for_writeext_pkg_open_for_write_beginext_pkg_open_for_write_commitext_pkg_inquire_openedext_pkg_open_for_update ext_pkg_ioclose ext_pkg_read_field ext_pkg_write_fieldext_pkg_get_next_var