### 2.2.3.4. Adjustable Parameters and Physical Constants[¶](#adjustable-parameters-and-physical-constants "Permalink to this headline")

Values of certain adjustable parameters inherent in the biogeophysical or biogeochemical parameterizations have either been obtained from the literature or calibrated based on comparisons with observations. These are described in the text. Physical constants, generally shared by all of the components in the coupled modeling system, are presented in [Table 2.2.7](#table-physical-constants).

Table 2.2.7 Physical constants[¶](#id21 "Permalink to this table")    
| description
 | name

 | value

 | units

 |
| --- | --- | --- | --- |
| Pi

 | \\(\\pi\\)

 | 3.14159265358979323846

 | \-

 |
| Acceleration of gravity

 | \\(g\\)

 | 9.80616

 | m s\-2

 |
| Standard pressure

 | \\(P\_{std}\\)

 | 101325

 | Pa

 |
| Stefan-Boltzmann constant

 | \\(\\sigma\\)

 | 5.67 \\(\\times 10^{-8}\\)

 | W m \-2 K \\({}^{-4}\\)

 |
| Boltzmann constant

 | \\(\\kappa\\)

 | 1.38065 \\(\\times 10^{-23}\\)

 | J K \-1 molecule \-1

 |
| Avogadro’s number

 | \\(N\_{A}\\)

 | 6.02214 \\(\\times 10^{26}\\)

 | molecule kmol\-1

 |
| Universal gas constant

 | \\(R\_{gas}\\)

 | \\(N\_{A} \\kappa\\)

 | J K \-1 kmol \-1

 |
| Molecular weight of dry air

 | \\(MW\_{da}\\)

 | 28.966

 | kg kmol \-1

 |
| Dry air gas constant

 | \\(R\_{da}\\)

 | \\({R\_{gas} \\mathord{\\left/ {\\vphantom {R\_{gas} MW\_{da} }} \\right.} MW\_{da} }\\)

 | J K \-1 kg \-1

 |
| Molecular weight of water vapor

 | \\(MW\_{wv}\\)

 | 18.016

 | kg kmol \-1

 |
| Water vapor gas constant

 | \\(R\_{wv}\\)

 | \\({R\_{gas} \\mathord{\\left/ {\\vphantom {R\_{gas} MW\_{wv} }} \\right.} MW\_{wv} }\\)

 | J K \-1 kg \-1

 |
| Von Karman constant

 | \\(k\\)

 | 0.4

 | \-

 |
| Freezing temperature of fresh water

 | \\(T\_{f}\\)

 | 273.15

 | K

 |
| Density of liquid water

 | \\(\\rho \_{liq}\\)

 | 1000

 | kg m \-3

 |
| Density of ice

 | \\(\\rho \_{ice}\\)

 | 917

 | kg m \-3

 |
| Specific heat capacity of dry air

 | \\(C\_{p}\\)

 | 1.00464 \\(\\times 10^{3}\\)

 | J kg \-1 K \-1

 |
| Specific heat capacity of water

 | \\(C\_{liq}\\)

 | 4.188 \\(\\times 10^{3}\\)

 | J kg \-1 K \-1

 |
| Specific heat capacity of ice

 | \\(C\_{ice}\\)

 | 2.11727 \\(\\times 10^{3}\\)

 | J kg \-1 K \-1

 |
| Latent heat of vaporization

 | \\(\\lambda \_{vap}\\)

 | 2.501 \\(\\times 10^{6}\\)

 | J kg \-1

 |
| Latent heat of fusion

 | \\(L\_{f}\\)

 | 3.337 \\(\\times 10^{5}\\)

 | J kg \-1

 |
| Latent heat of sublimation

 | \\(\\lambda \_{sub}\\)

 | \\(\\lambda \_{vap} +L\_{f}\\)

 | J kg \-1

 |
| 1 “Thermal conductivity of water”

 | \\(\\lambda \_{liq}\\)

 | 0.57

 | W m \-1 K \-1

 |
| 1 “Thermal conductivity of ice”

 | \\(\\lambda \_{ice}\\)

 | 2.29

 | W m \-1 K \-1

 |
| 1 “Thermal conductivity of air”

 | \\(\\lambda \_{air}\\)

 | 0.023 W m \-1 K \-1

 |  |
| Radius of the earth

 | \\(R\_{e}\\)

 | 6.37122

 | \\(\\times 10^{6}\\) m

 |

1Not shared by other components of the coupled modeling system.
