Model:TopoFlow-Snowmelt-Energy Balance: Difference between revisions
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Q_LW = net longwave radiation (W / m^2) | Q_LW = net longwave radiation (W / m^2) | ||
T_air = air temperature (deg C) | T_air = air temperature (deg C) | ||
T_surf | T_surf = surface (snow) temperature (deg C) | ||
RH = relative humidity (none) (in (0,1)) | RH = relative humidity (none) (in (0,1)) | ||
p_0 = atmospheric pressure (mbar) | p_0 = atmospheric pressure (mbar) | ||
u_z = wind velocity at height z (m / s) | u_z = wind velocity at height z (m / s) | ||
z = reference height for wind (m) | z = reference height for wind (m) | ||
z0_air | z0_air = surface roughness height (m) | ||
h0_snow = initial snow depth (m) | h0_snow = initial snow depth (m) | ||
h0_swe | h0_swe = initial depth, snow water equivalent (m) | ||
ρ_snow | ρ_snow = density of the snow (kg / m^3) | ||
c_snow | c_snow = specific heat capacity of snow (J / (kg deg_C)) | ||
ρ_air = density of the air (kg / m^3) | ρ_air = density of the air (kg / m^3) | ||
c_air = specific heat capacity of air (J / (kg deg_C)) | c_air = specific heat capacity of air (J / (kg deg_C)) | ||
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L_v = latent heat of vaporization, water (J / kg) (2500000) | L_v = latent heat of vaporization, water (J / kg) (2500000) | ||
e_air = air vapor pressure at height z (mbar) | e_air = air vapor pressure at height z (mbar) | ||
e_surf | e_surf = vapor pressure at the surface (mbar) | ||
g = gravitational constant = 9.81 (m / s^2) | g = gravitational constant = 9.81 (m / s^2) | ||
κ = von Karman's constant = 0.41 (unitless) | κ = von Karman's constant = 0.41 (unitless) | ||
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Save sw pixels: 0 Case5_0D-hswe.txt (m) | Save sw pixels: 0 Case5_0D-hswe.txt (m) | ||
Save cc pixels: 0 Case5_0D-Ecc.txt (J/m^2) | Save cc pixels: 0 Case5_0D-Ecc.txt (J/m^2) | ||
|Input format=ASCII, Binary | |Input format=ASCII, Binary | ||
|Output format=ASCII, Binary | |Output format=ASCII, Binary | ||
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D_e = D_h = bulk exchange coefficient for vapor (m / s) | D_e = D_h = bulk exchange coefficient for vapor (m / s) | ||
Ri = g * z * (T_air - T_surf) / (u_z^2 (T_air + 273.15)) = Richardson's number (unitless) | Ri = g * z * (T_air - T_surf) / (u_z^2 (T_air + 273.15)) = Richardson's number (unitless) | ||
Q_cc = (see note below) = cold content flux (W / m^2) | Q_cc = (see note below) = cold content flux (W / m^2) | ||
E_cc(0) = h0_snow * ρ_snow * c_snow * (T_0 - T_snow) = initial cold content (J / m^2) (T0 = 0 now) | E_cc(0) = h0_snow * ρ_snow * c_snow * (T_0 - T_snow) = initial cold content (J / m^2) (T0 = 0 now) | ||
e_air = e_sat(T_air) * RH = vapor pressure of air (mbar) | e_air = e_sat(T_air) * RH = vapor pressure of air (mbar) | ||
e_surf = e_sat(T_surf) = vapor pressure at surface (mbar) | e_surf = e_sat(T_surf) = vapor pressure at surface (mbar) | ||
e_sat = 6.11 * exp((17.3 * T) / (T + 237.3)) = saturation vapor pressure (mbar, not KPa), Brutsaert (1975) | e_sat = 6.11 * exp((17.3 * T) / (T + 237.3)) = saturation vapor pressure (mbar, not KPa), Brutsaert (1975) | ||
|Describe length scale and resolution constraints=Recommended grid cell size is around 100 meters, but can be parameterized to run with a wide range of grid cell sizes. DEM grid dimensions are typically less than 1000 columns by 1000 rows. | |Describe length scale and resolution constraints=Recommended grid cell size is around 100 meters, but can be parameterized to run with a wide range of grid cell sizes. DEM grid dimensions are typically less than 1000 columns by 1000 rows. | ||
|Describe time scale and resolution constraints=The basic stability condition is: dt < (dx / u_min), where dt is the timestep, dx is the grid cell size and u_min is the smallest velocity in the grid. This ensures that flow cannot cross a grid cell in less than one time step. Typical timesteps are on the order of seconds to minutes. Model can be run for a full year or longer, if necessary. | |Describe time scale and resolution constraints=The basic stability condition is: dt < (dx / u_min), where dt is the timestep, dx is the grid cell size and u_min is the smallest velocity in the grid. This ensures that flow cannot cross a grid cell in less than one time step. Typical timesteps are on the order of seconds to minutes. Model can be run for a full year or longer, if necessary. |
Revision as of 18:13, 17 February 2010
Contact
Name | Scott Peckham |
Type of contact | Model developer |
Institute / Organization | CSDMS, INSTAAR, University of Colorado |
Postal address 1 | 1560 30th street |
Postal address 2 | |
Town / City | Boulder |
Postal code | 80305 |
State | Colorado |
Country | USA"USA" is not in the list (Afghanistan, Albania, Algeria, Andorra, Angola, Antigua and Barbuda, Argentina, Armenia, Australia, Austria, ...) of allowed values for the "Country" property. |
Email address | Scott.Peckham@colorado.edu |
Phone | 303-492-6752 |
Fax |
TopoFlow-Snowmelt-Energy Balance
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