Back Goto VIC Operations Page Goto VIC Model Home Page Next

Soil Parameter File

Soil hydrologic and thermal parameters needed for the different VIC model set-ups are listed below. All columns of the input file must be filled, but certain parameters need only be defined if the full energy or frozen soil models are activated. Red text indicates parameters needed for the energy balance model. Violet text indicates parameters needed for the frozen soil model. Header lines can be added by starting the line with a '#'.

The following icons are used to identify changes between version 3.2.1 and 4.0 in the documentation:

  • indicates new features added to the code,
  • indicates features no longer available in the code,
  • indicates features that have been modified.
    •

    In previous versions certain parameters were read as average values for the entire soil column. In version 4.0 all soil parameter values are now read for all layers. Converting the soil parameter file from older model versions, should simply require copying column average values to separate columns for each soil moisture layer.

    Column

    Variable Name

    Units

    Number of Values

    Description

    1

     

    N/A

     1

    1 = Run Grid Cell, 0 = Do Not Run

    2

    gridcel

    N/A

     1

    Grid cell number

    3

    lat

    degrees

     1

    Latitude of grid cell

    4

    lon

    degrees

     1

    Longitude of grid cell

    5

    infilt

    N/A

     1

    Variable infiltration curve parameter (binfilt)

    6

    Ds

    fraction

     1

    Fraction of Dsmax where non-linear baseflow begins

    7

    Dsmax

    mm/day

     1

    Maximum velocity of baseflow

    8

    Ws

    fraction

     1

    Fraction of maximum soil moisture where non-linear baseflow occurs

    9

    c

    N/A

     1

    Exponent used in baseflow curve, normally set to 2

    10 : (Nlayer+9)

    expt

    N/A

    Nlayer

    Parameter describing the variation of Ksat with soil moisture

    (Nlayer+10) :(2*Nlayer+9)

    Ksat

    mm/day

    Nlayer

    Saturated hydrologic conductivity

    (2*Nlayer+10):(3*Nlayer+9)

    phi_s

    mm/mm

    Nlayer

    Soil moisture diffusion parameter

    (3*Nlayer+10):(4*Nlayer+9)

    init_moist

    mm

    Nlayer

    Initial layer moisture content

    (4*Nlayer+10)

    elev

    m

     1

    Average elevation of grid cell

    (4*Nlayer+11):(5*Nlayer+10)

    depth

    m

    Nlayer

    Thickness of each soil moisture layer

    (5*Nlayer+11)

    avg_T

    C

     1

    Average soil temperature, used as the bottom boundary for soil heat flux solutions

    (5*Nlayer+12)

    dp

    m

     1

    Soil thermal damping depth (depth at which soil temperature remains constant through the year, ~4 m)

    (5*Nlayer+13):(6*Nlayer+12)

    bubble

    cm

     Nlayer

    Bubbling pressure of soil

    (6*Nlayer+13):(7*Nlayer+12)

    quartz

    fraction

     Nlayer

    Quartz content of soil

    (7*Nlayer+13):(8*Nlayer+12)

    bulk_density

    kg/m3

    Nlayer

    Bulk density of soil layer

    (8*Nlayer+13):(9*Nlayer+12)

    soil_density

    kg/m3

    Nlayer

    Soil particle density, normally 2685 kg/m3

    (9*Nlayer+13)

    off_gmt

    hours

     1

    Time zone offset from GMT

    (9*Nlayer+14):(10*Nlayer+13)

    Wcr_FRACT

    fraction

     Nlayer

    Fractional soil moisture content at the critical point (~70% of field capacity) (fraction of maximum moisture)

    (10*Nlayer+14):(11*Nlayers+13)

    Wpwp_FRACT

    fraction

     Nlayer

    Fractional soil moisture content at the wilting point (fraction of maximum moisture)

    (11*Nlayer+14)

    rough

    m

     1

    Surface roughness of bare soil

    (11*Nlayer+15)

    snow_rough

    m

     1

    Surface roughness of snowpack

    (11*Nlayer+16)

    annual_prec

    mm

    1

    Average annual precipitation.

    (11*Nlayer+17):(12*Nlayer+16)

    resid_moist

    fraction

    Nlayer

    Soil moisture layer residual moisture.

    (12*Nlayer+17)

    fs_active

    1 or 0

    1

    If set to 1, then frozen soil algorithm is activated for the grid cell. A 0 indicates that frozen soils are not computed even if soil temperatures fall below 0C.

    (12*Nlayer+18)

    July_Tavg

    C

     1

    Average July soil temperature, used for treeline computations (if JULY_TAVG_SUPPLIED=TRUE in the global control file).

    Example Soil Parameter File:

    Example Soil Parameter File: VIC 4.0.5/4.0.6 Water Balance 

    #RUN	GRID	LAT	LNG	INFILT	Ds	Ds_MAX	Ws	C	EXPT_1	EXPT_2	EXPT_3	Ksat_1	Ksat_2	Ksat_3	PHI_1	PHI_2	PHI_3	MOIST_1	MOIST_2	MOIST_3	ELEV	DEPTH_1	DEPTH_2	DEPTH_3	AVG_T	DP	BUBLE1	BUBLE2	BUBLE3	QUARZ1	QUARZ2	QUARZ3	BULKDN1	BULKDN2	BULKDN3	PARTDN1	PARTDN2	PARTDN3	OFF_GMT	WcrFT1	WcrFT2	WcrFT3	WpFT1	WpFT2	WpFT3	Z0_SOIL	Z0_SNOW	PRCP	RESM1	RESM2	RESM3	FS_ACTV	JULY_TAVG
1	7	43.739	-92.4.0	0.010	1.e-4	3.05	0.93	2	4.0	4.0	4.0	250.0	250.0	250.0	-999	-999	-999	0.4	0.4	0.4	306.3	0.1	6.90	2.000	14.0	4.0	75.0	75.0	75.0	0.24	0.24	0.24	1306	1367	1367	2650	2650	2650	-6	0.330	0.330	0.330	0.133	0.133	0.133	0.001	0.010	500	0.02	0.02	0.02	1	18.665

    Back Goto VIC Operations Page Goto VIC Model Home Page Next

    Goto Hydrologic Models Page Goto CE Home Page Goto CE Home Page Goto UW Home Page

    VIC Administrator
    Last modified: Wed May 2 12:29:50 PDT 2007