Operative Environmental Temperature of an Ectotherm Based on Gates (1980)

The function predicts body temperatures (C, operative environmental temperature) of an ectotherm using the approximation in Gates (1980) . The functions omits evaporative and metabolic heat loss (Mitchell 1976; Kingsolver 1983) .

Tb_Gates(
  A,
  D,
  psa_dir,
  psa_ref,
  psa_air,
  psa_g,
  T_g,
  T_a,
  Qabs,
  epsilon,
  H_L,
  ef = 1.3,
  K
)

Arguments

A

numeric surface area (m²).

D

numeric characteristic dimension for conduction (meters).

psa_dir

numeric view factor for the proportion surface area exposed to direct radiation from the sky (or enclosure) (0-1).

psa_ref

numeric view factor for proportion surface area exposed to reflected radiation from the ground (0-1).

psa_air

numeric proportion surface area exposed to air (0-1).

psa_g

numeric proportion surface area in contact with substrate (0-1).

T_g

numeric ground surface temperature (C).

T_a

numeric ambient air temperature (C).

Qabs

numeric Solar radiation absorbed (W).

epsilon

numeric longwave infrared emissivity of skin (proportion), 0.95 to 1 for most animals (Gates 1980) .

H_L

numeric Convective heat transfer coefficient (W m^-2 K^-1).

ef

numeric enhancement factor used to adjust H_L to field conditions using h_L approximation from Mitchell (1976) . Approximated as 1.23 by default, but see Mitchell (1976) for relationship.

K

numeric Thermal conductivity (W K^-1 m^-1), K = 0.5 W K^-1 m^-1 for naked skin, K = 0.15 W K^-1 m^-1for insect cuticle Galushko et al. (2005) ; conductivity of the ground is generally greater than that of animal tissues, so animal thermal conductivity is generally the rate limiting step.

Value

numeric operative environmental temperature, T_e (C).

References

Galushko D, Ermakov N, Karpovski M, Palevski A, Ishay JS, Bergman DJ (2005). “Electrical, thermoelectric and thermophysical properties of hornet cuticle.” Semiconductor Science and Technology, 20(3), 286--289. doi:10.1088/0268-1242/20/3/005 .

Gates DM (1980). Biophysical Ecology. Springer-Verlag, New York, NY, USA.

Kingsolver JG (1983). “Thermoregulation and Flight in Colias Butterflies: Elevational Patterns and Mechanistic Limitations.” Ecology, 64(3), 534-545. doi:10.2307/1939973 .

Mitchell JW (1976). “Heat transfer from spheres and other animal forms.” Biophysical Journal, 16(6), 561-569. ISSN 0006-3495, doi:10.1016/S0006-3495(76)85711-6 .

See also

Other biophysical models: Grashof_number_Gates(), Grashof_number(), Nusselt_from_Grashof(), Nusselt_from_Reynolds(), Nusselt_number(), Prandtl_number(), Qconduction_animal(), Qconduction_substrate(), Qconvection(), Qemitted_thermal_radiation(), Qevaporation(), Qmetabolism_from_mass_temp(), Qmetabolism_from_mass(), Qnet_Gates(), Qradiation_absorbed(), Qthermal_radiation_absorbed(), Reynolds_number(), T_sky(), Tb_CampbellNorman(), Tb_Gates2(), Tb_butterfly(), Tb_grasshopper(), Tb_limpetBH(), Tb_limpet(), Tb_lizard_Fei(), Tb_lizard(), Tb_mussel(), Tb_salamander_humid(), Tb_snail(), Tbed_mussel(), Tsoil(), actual_vapor_pressure(), boundary_layer_resistance(), external_resistance_to_water_vapor_transfer(), free_or_forced_convection(), heat_transfer_coefficient_approximation(), heat_transfer_coefficient_simple(), heat_transfer_coefficient(), saturation_vapor_pressure(), saturation_water_vapor_pressure()

Examples

 Tb_Gates (A       = 0.1, 
           D       = 0.025, 
           psa_dir = 0.6, 
           psa_ref = 0.4, 
           psa_air = 0.5, 
           psa_g   = 0.1, 
           T_g     = 30, 
           T_a     = 37, 
           Qabs    = 2, 
           epsilon = 0.95, 
           H_L     = 10, 
           ef      = 1.23, 
           K       = 0.5)
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