get_p_wet: Function to find effective proportion of surface area that is...

In mrke/NicheMapR: R implementation of Niche Mapper software for biophysical modelling

Function to find effective proportion of surface area that is wet from experimental water loss data

Description

A set of equations for computing the proportion of the total surface area of an organism that is acting as a free water surface for evaporation, which is used in the ectotherm model of NicheMapR NicheMapR to compute cutaneous water loss rates. This function requires the WETAIR and DRYAIR functions of NicheMapR. Elia Pirtle and Michael Kearney developed this R function and example in November 2017.

Usage

get_p_wet(cut.known = 1, E_tot = 0.344 / 60 / 1000, E_cut = 0.108 / 60 / 1000, T_b = 25, RHin = 30, vel = 0.0021)

Arguments

cut.known	= 0, Is cutaneous water loss supplied? 0 = no (invokes estimation by partitioning respiratory), 1 = yes
resp.known	= 0, Is respiratory water loss supplied? 0 = no (invokes estimation by partitioning respiratory), 1 = yes
eye.known	= 0, Is ocular water loss supplied? 0 = no (invokes estimation by ocular surface area paritioning), 1 = yes
vent.known	= 0, Is ventilation rate supplied? 0 = no (rely on estimate from V_O2), 1 = yes
press.known	= 0, Is barometric pressure known (1, uses altitude) or has it been provided as the 'bp' variable (0)
A_tot.known	= 0, Is total surface area known? 0 = no (uses Meeh's formula A_tot = 10 x mass.g ^ (2/3) / 10000), 1 = yes
E_tot	= 0.344 / 60 / 1000, Observed total evaporative water loss rate, g/s
E_cut	= 0.108 / 60 / 1000, Observed cutaneous evaporative water loss rate, g/s
E_resp	= 0.0371 / 60 / 1000, Observed respiratory evaporative water loss rate, g/s
E_eye	= 0.199 / 60 / 1000, Observed ocular evaporative water loss rate, g/s
mass.g	= 26.7, Wet mass of animal, g
A_tot	= 0.00894, Total surface area, m2
fcond	= 0.25, Fraction of total area area touching surfaces, dec% (therefore no evaporation or convection)
feye	= 0.002, Fraction of total area area comprising both eyes
eye_frac	= 0.58, Fraction of time eye is open, 1 meaning both eyes fully open, dec%
T_b	= 25, Core body temperature, °C
T_s	= 24.99, Skin (surface) temperature, °C
T_a	= 24.98, Air temperature, °C
vel	= 0.0021, wind speed, m / s
RHex	= 100, relative humidity of exhaled air, %
RHin	= 30, relative humidity of atmosphere, %
E_O2	= 15, Oxygen extraction efficiency, %
RQ	= 0.766, Respiratory quotient, dec%
M_1	= 0.013, Metabolic rate equation parameter 1 V_O2 = M_1 * M ^ M_2 * 10 ^ (M_3 * T_b) based on Eq. 2 from Andrews & Pough 1985. Physiol. Zool. 58:214-231
M_2	= 0.800, Metabolic rate equation parameter 2
M_3	= 0.038, Metabolic rate equation parameter 3
V_O2_STP	= M_1 * mass.g ^ M_2 * 10 ^ (M_3 * T_b) / 3600 / 1000, Oxygen consumption rate corrected to STP, L O2 / s
T_ref_O2	= 25, Reference temperature for oxygen consumption rate correction (°C)
V_air_STP	= V_O2_STP / (0.2094 * E_O2 / 100), Ventilation rate at STP, L/s
rho_flesh	= 1000, Density of flesh (kg/m3)
T_ref_vent	= 25, Reference temperature for ventilation rate correction (°C)
T_A	= 8817, Arhhenius temperature (K)
T_AL	= 50000, Arrhenius temperature for decrease below lower boundary of tolerance range T_L (K)
T_AH	= 90000, Arrhenius temperature for decrease above upper boundary of tolerance range T_H (K)
T_L	= 279, Lower boundary (K) of temperature tolerance range for Arrhenius thermal response
T_H	= 306, Upper boundary (K) of temperature tolerance range for Arrhenius thermal response
alt	= 0.03, Altitude (km)
bp	= 101325, Barometric pressure (pascal)

Value

E_tot total evaporative water loss, g/s

E_cut cutaneous evaporative water loss, g/s

E_resp respiratory evaporative water loss, g/s

E_eye ocular evaporative water loss, g/s

R_a boundary layer resitance, s/m

R_s skin resistance, s/m

A_tot total surface area, m2

A_eye ocular surface area, m2

A_eff effective area for evaporation, m2

A_wet area acting as a free water surface, m2

p_wet proportion of surface area acting as a free water surface, dec%

mrke/NicheMapR documentation built on June 9, 2024, 12:38 p.m.