ARC/INFO ASCII Grid Soil Parameter Files

The model first reads a file listing the names of all of the needed soil parameters. It then reads each soil parameter file and extracts the parameter value for the current grid cell.

Soil hydrologic and thermal parameters needed for the different VIC model set-ups are listed below. All input files must be available, 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 '#'.

Special utility programs and scripts are available for manipulating the parameters within the grid files.

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.

File List File

File names must be in the order listed below, skipped or names out of order may not necessarily crash the model, but will yield incorrect results.

In version 4.0 average soil column parameters were replaced with average layer parameters. Soil parameter files for older versions of the model can be updated by using the average soil column parameter file for each soil moisture layer parameter.

File Number	Parameter	Units	Description
1	cell number	N/A	Grid cell numbers
2	run flag	N/A	Flag to indicate whether grid cell is run: 1 = run current cell
3	dem	m	Grid cell elevation file
4	b_infilt	N/A	Variable infiltration curve parameter (b_infilt)
5	Ds	fraction	Fraction of Dsmax where non-linear baseflow begins
6	Dsmax	mm/day	Maximum velocity of baseflow
7	Ws	fraction	Fraction of maximum soil moisture where non-linear baseflow occurs
8	c	N/A	Exponent used in infiltration curve, normally set to 2
9	avg_T	C	Average soil temperature, used as the bottom boundary for soil heat flux solutions
10	dp	m	Soil thermal damping depth (depth at which soil temperature remains constant through the year, ~4 m)
11	off_gmt	hours	Time zone offset from GMT
12:(Nlayer+11)	Wcr_FRACT	fraction	Fractional soil moisture content of each soil moisture layer at the critical point (~70% of field capacity) (fraction of maximum moisture).
(Nlayer+12):(2*Nlayer+11)	Wpwp_FRACT	fraction	Fractional soil moisture content of each soil moisture layer at the wilting point (fraction of maximum moisture)
(2*Nlayer+12)	rough	m	Surface roughness of bare soil
(2*Nlayer+13)	snow_rough	m	Surface roughness of snowpack
(2*Nlayer+14)	annual_prec	mm	Average annual precipitation
(2Nlayer+15): (3Nlayer+14)	sand	percent	Percent sand in the current layer.
(3Nlayer+15): (4Nlayer+14)	clay	percent	Percent clay in the current layer.
(4Nlayer+15): (5Nlayer+14)	Ksat	mm/day	Saturated hydraulic conductivity of the current layer.
(5Nlayer+15): (6Nlayer+14)	phi_s	mm/mm	Soil moisture diffusion coefficient.
(6Nlayer+15): (7Nlayer+14)	init_moist	mm	Initial moisture content of current layer.
(7Nlayer+15): (8Nlayer+14)	depth	m	Thickness of current layer.
(8Nlayer+15): (9Nlayer+14)	bulk density	kg/m³	Bulk density of current layer.
(9Nlayer+15): (10Nlayer+14)	porosity	fraction	Porosity of current layer.
(10*Nlayer+15)	fs_active	1 or 0	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.

Example File List File:

File is for the Illinois River within the Upper Mississippi Basin (upm), some parameters are down subdirectories for the current calibration run (ILL_CALIB17).

cellnum.upm
ill_run.asc
upm_dem.asc
ILL_CALIB17/b_infilt.upm
ILL_CALIB17/Ds.upm
Dsmax.upm
ILL_CALIB17/Ws.upm
c.upm
avg_temp.upm
dp.upm
off_gmt.upm
Wcr_fix.upm
Wcr_fix.upm 
Wcr_fix.upm 
Wpwp_fix.upm
Wpwp_fix.upm 
Wpwp_fix.upm 
rough.upm
snow_rough.upm
annual_prec.upm
annual_prec.upm
sand_l0.asc
sand_l1.asc
sand_l1.asc
clay_l0.asc
clay_l1.asc
clay_l1.asc
ILL_CALIB17/Ksat.asc
ILL_CALIB17/Ksat2.upm
ILL_CALIB17/Ksat2.upm
phi_s.upm
phi_s.upm
phi_s.upm
init_moist1.upm
init_moist2.upm
init_moist3.upm
ILL_CALIB17/depth1.upm
ILL_CALIB17/depth2.upm
ILL_CALIB17/depth3.upm
bulk_l0.asc
bulk_l1.asc
bulk_l1.asc
poro_l0.asc
poro_l1.asc
poro_l1.asc
fs_active.asc

Example ARC/INFO Gridded File:

Cell number file for the Upper Mississippi

ncols         22
nrows         19
xllcorner     -97.00
yllcorner     38.5
cellsize      0.50
NODATA_value  -9999
-9999 -9999 -9999     1     2     3     4     5 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999
-9999 -9999 -9999     6     7     8     9    10 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999
-9999 -9999    11    12    13    14    15    16    17 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999
-9999 -9999    18    19    20    21    22    23    24    25    26    27    28    29    30    31 -9999 -9999 -9999 -9999 -9999 -9999
   32 -9999    33    34    35    36    37    38    39    40    41    42    43    44    45    46 -9999 -9999 -9999 -9999 -9999 -9999
   47    48    49    50    51    52    53    54    55    56    57    58    59    60    61    62 -9999 -9999 -9999 -9999 -9999 -9999
   63    64    65    66    67    68    69    70    71    72    73    74    75    76    77    78 -9999 -9999 -9999 -9999 -9999 -9999
-9999    79    80    81    82    83    84    85    86    87    88    89    90    91    92 -9999 -9999 -9999 -9999 -9999 -9999 -9999
-9999 -9999    93    94    95    96    97    98    99   100   101   102   103   104   105   106   107 -9999 -9999 -9999 -9999 -9999
-9999 -9999 -9999   108   109   110   111   112   113   114   115   116   117   118   119   120   121   122 -9999 -9999 -9999 -9999
-9999 -9999 -9999   123   124   125   126   127   128   129   130   131   132   133   134   135   136   137 -9999 -9999 -9999 -9999
-9999 -9999 -9999   138   139   140   141   142   143   144   145   146   147   148   149   150   151   152 -9999 -9999 -9999 -9999
-9999 -9999 -9999 -9999   153   154   155   156   157   158   159   160   161   162   163   164   165   166   167 -9999   168   169
-9999 -9999 -9999 -9999 -9999   170   171   172   173   174   175   176   177   178   179   180   181   182   183   184   185   186
-9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999   187   188   189   190   191   192   193   194   195   196   197   198 -9999 -9999
-9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999   199   200   201   202   203   204   205   206   207   208 -9999 -9999 -9999 -9999
-9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999   209   210   211   212   213   214   215   216 -9999 -9999 -9999 -9999 -9999
-9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999   217   218   219   220   221   222   223 -9999 -9999 -9999 -9999 -9999 -9999
-9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999   224   225   226 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999

VIC Administrator

Last modified: Fri May 12 14:28:53 PDT 2000

ARC/INFO ASCII Grid Soil Parameter Files

File List File

File Number

Parameter

Units

Description

Example File List File:

Example ARC/INFO Gridded File: