bigleaf.constants {bigleaf} | R Documentation |
Constants Used in the bigleaf Package
Description
This function defines the following constants:
Usage
bigleaf.constants(
cp = 1004.834,
Rgas = 8.31451,
Rv = 461.5,
Rd = 287.0586,
Md = 0.0289645,
Mw = 0.0180153,
eps = 0.622,
g = 9.81,
solar_constant = 1366.1,
pressure0 = 101325,
Tair0 = 273.15,
k = 0.41,
Cmol = 0.012011,
Omol = 0.0159994,
H2Omol = 0.01801528,
sigma = 5.670367e-08,
Pr = 0.71,
Sc_CO2 = 1.07,
Le067 = 0.93,
Kelvin = 273.15,
DwDc = 1.6,
days2seconds = 86400,
kPa2Pa = 1000,
Pa2kPa = 0.001,
umol2mol = 1e-06,
mol2umol = 1e+06,
kg2g = 1000,
g2kg = 0.001,
kJ2J = 1000,
J2kJ = 0.001,
se_median = 1.253,
frac2percent = 100
)
Arguments
cp |
Specific heat of air for constant pressure (J K-1 kg-1) |
Rgas |
Universal gas constant (J mol-1 K-1) |
Rv |
Gas constant of water vapor (J kg-1 K-1) (Stull 1988 p.641) |
Rd |
Gas constant of dry air (J kg-1 K-1) (Foken p. 245) |
Md |
Molar mass of dry air (kg mol-1) |
Mw |
Molar mass of water vapor (kg mol-1) |
eps |
Ratio of the molecular weight of water vapor to dry air (=Mw/Md) |
g |
Gravitational acceleration (m s-2) |
solar_constant |
Solar constant (W m-2) |
pressure0 |
Reference atmospheric pressure at sea level (Pa) |
Tair0 |
Reference air temperature (K) |
k |
von Karman constant |
Cmol |
Molar mass of carbon (kg mol-1) |
Omol |
Molar mass of oxygen (kg mol-1) |
H2Omol |
Molar mass of water (kg mol-1) |
sigma |
Stefan-Boltzmann constant (W m-2 K-4) |
Pr |
Prandtl number |
Sc_CO2 |
Schmidt number for CO2 |
Le067 |
Lewis number for water vapor to the power of 0.67 |
Kelvin |
Conversion degree Celsius to Kelvin |
DwDc |
Ratio of the molecular diffusivities for water vapor and CO2 |
days2seconds |
Seconds per day |
kPa2Pa |
Conversion kilopascal (kPa) to pascal (Pa) |
Pa2kPa |
Conversion pascal (Pa) to kilopascal (kPa) |
umol2mol |
Conversion micromole (umol) to mole (mol) |
mol2umol |
Conversion mole (mol) to micromole (umol) |
kg2g |
Conversion kilogram (kg) to gram (g) |
g2kg |
Conversion gram (g) to kilogram (kg) |
kJ2J |
Conversion kilojoule (kJ) to joule (J) |
J2kJ |
Conversion joule (J) to kilojoule (kJ) |
se_median |
Conversion standard error (SE) of the mean to SE of the median |
frac2percent |
Conversion between fraction and percent |
Details
This function is passed as an argument to every function that uses one or more constants. Individual constants passed to a function can be easily altered. E.g. the following command will change the value of the von Karman constant from 0.41 to 0.4:
bigleaf.constants(k=0.4)
the value of a constant can be returned by calling:
bigleaf.constants()$*name_of_constant*
To permanently change the constants contained within this function (which
makes sense for some of them, e.g. for the von Karman constant),
the command fixInNamespace
can be used. E.g.
fixInNamespace(bigleaf.constants,ns="bigleaf")
Note that this has to be repeated every time the package is newly installed/loaded.