Package 'gunit'

Convert conductance units

Description

Convert conductance units

Usage

convert_conductance(
  .g,
  P = set_units(101.3246, kPa),
  R = set_units(8.31446, J/K/mol),
  Temp = set_units(298.15, K)
)

Arguments

.g	Conductance in class units. Units must convertible to one of "m/s", "umol/m^2/s/Pa", or "mol/m^2/s"
P	A pressure value of class units that is convertible to kPa. Default is 101.3246 kPa, Earth's atmospheric pressure at sea level.
R	Ideal gas constant of class units that is convertible to J/K/kg. Default is 8.31446 J/K/mol.
Temp	A temperature value of class units that is convertible to K. Default is 25 degreeC (298.15 K).

Value

@return a tibble in units "m/s", "umol/m^2/s/Pa", and "mol/m^2/s".

Examples

# library(gunit)
library(units)

g_sc <- set_units(10, "m/s")
convert_conductance(g_sc)

g_sc <- set_units(4, "umol/m^2/s/Pa")
convert_conductance(g_sc)

g_sc <- set_units(0.4, "mol/m^2/s")
convert_conductance(g_sc)

---

gunit package

Description

Convert Conductance Units

Details

See the README on GitHub

---

Convert g_c ($\mu$mol CO2/m^2/s/Pa) to g_w ($\mu$mol H2O /m^2/s/Pa)

Description

Convert g_c ($\mu$mol CO2/m^2/s/Pa) to g_w ($\mu$mol H2O /m^2/s/Pa)

Convert g_c (umol CO2/m^2/s/Pa) to g_w (umol H2O /m^2/s/Pa)

Usage

gw2gc(g_w, D_c, D_w, unitless, a)

gc2gw(g_c, D_c, D_w, unitless, a)

Arguments

g_w	conductance to water vapor in units ($\mu$mol H2O / (m^2 s Pa)) of class units.
D_c	diffusion coefficient for CO2 in air in units of m^2/s of class units
D_w	diffusion coefficient for H2O in air in units of m^2/s of class units
unitless	Logical. Should scientific units of arguments be checked and set? TRUE is safer, but slower. If FALSE, values provided are assumed to be in correct units. units
a	exponent used for conversion. Use 1 for still air; 0.67 for laminar flow (Jones 2014). Should be unitless.
g_c	conductance to CO2 in units ($\mu$mol H2O / (m^2 s Pa)) of class units.

Details

Diffusive conductance to CO2 is greater than that of H2O because of the higher molecular weight. To convert:

$g_\mathrm{c} = g_\mathrm{w} (D_\mathrm{c} / D_\mathrm{w}) ^ a$

$g_\mathrm{w} = g_\mathrm{c} (D_\mathrm{w} / D_\mathrm{c}) ^ a$

Value

Value with units $\mu$mol / (m^2 s Pa) of class units.

Note

This function will soon be moving to the standalone gunit package.

References

Jones H. 2014. Plants and Microclimate (3rd edition). Cambridge University Press.

Examples

library(units)
D_c = set_units(1.29e-05, "m^2/s")
D_w = set_units(2.12e-05, "m^2/s")
g_c = set_units(3, "umol/m^2/s/Pa")
a = 1
g_w = gc2gw(g_c, D_c, D_w, a, unitless = FALSE)
g_w

gw2gc(g_w, D_c, D_w, a, unitless = FALSE)

---