knitr::opts_chunk$set( eval = TRUE, tidy.opts=list(width.cutoff=60), tidy=TRUE )
This document shows how to use the endoR.R
function of NicheMapR to compute endotherm heat and mass balances. This function collates all the different steps in Endotherm Components Tutorial into a single function, 'endoR', that can be applied to vectors of data. The latter calls a FORTRAN routine call 'SOLVENDO' (high speed calculation). An R equivalent of this, 'endoR_devel' (~ 9x slower), can be used for the development of algorithms for organism-specific sequences of thermoregulatory responses and then, if faster processing is required, a version of SOLVENDO can be modified accordingly. All the underlying theory, equations and subroutines are described in Endotherm Theory Tutorial.
Here is how you run the calculation with all default values, specifying a local air temperature of 0 $^{\circ}\text{C}$.
library(NicheMapR) library(knitr) endo.out <- endoR(TA = 0) treg <- as.data.frame(endo.out$treg) morph <- as.data.frame(endo.out$morph) enbal <- as.data.frame(endo.out$enbal) masbal <- as.data.frame(endo.out$masbal)
treg.lab <- c("core temperature (°C)", "lung temperature (°C)", "dorsal skin temperature (°C)", "ventral skin temperature (°C)", "dorsal fur/feather-air interface temperature (°C)", "ventral fur-air interface temperature (°C)", "current ratio between long and short axis due to postural change (-)", "breathing rate multiplier (-)", "part of the skin surface that is wet (%)", "thermal conductivity of flesh (W/mC)", "effective thermal conductivity of fur/feathers (W/mC)", "thermal conductivity of dorsal fur/feathers (W/mC)", "thermal conductivity of ventral fur/feathers (W/mC)", "thermal conductivity of compressed fur/feathers (W/mC)", "Q10 multiplier on metabolic rate (-)") morph.lab <- c("total outer surface area (m2)", "total volume (m3)","characteristic dimension for convection (m)", "fat mass (kg)", "thickness of fat layer (m)", "flesh volume (m3)", "length (m)", "width (m)", "height (m)", "diameter, core to skin (m)", "diameter, core to fur/feathers (m)", "silhouette area (m2)", "silhouette area normal to sun's rays (m2)", "silhouette area parallel to sun's rays (m2)", "total skin area (m2)", "skin area available for evaporation (m2)", "area for convection (m2)", "area for conduction (m2)", "configuration factor to sky (-)", "configuration factor to ground (-)") enbal.lab <- c("solar radiation absorbed (W)", "longwave (infra-red) radiation absorbed (W)", "metabolic heat generation (W)", "evaporation (W)", "longwave (infra-red) radiation lost (W)", "convection (W)", "conduction (W)", "energy balance (W)", "iterations required for a solution (-)", "was a solution found (0=no, 1=yes)") masbal.lab <- c("breating rate (L/h)", "oxgyen consumption rate (L/h)", "respiratory water loss (g/h)", "cutaneous water loss (g/h)", "oxygen inhaled (mol/h)", "oxygen expelled (mol/h)", "nitrogen inhaled (mol/h)", "nitrogen expelled (mol/h)", "air inhaled (mol/h)", "air expelled (mol/h)") kable(cbind(t(round(treg, 4)), treg.lab), col.names = c("value", "description and units"), caption = 'treg') kable(cbind(t(round(morph, 4)), morph.lab), col.names = c("value", "description and units"), caption = 'morph') kable(cbind(t(round(enbal, 4)), enbal.lab), col.names = c("value", "description and units"), caption = 'enbal') kable(cbind(t(round(masbal, 4)), masbal.lab), col.names = c("value", "description and units"), caption = 'masbal')
Now try a sequence of air temperatures for a specified core temperature, mass, fur/feather depth and base skin wetness, with the option to sweat at 0.25 % increments to cool down if needed. Note that the default settings make the environment a black-body one (all surface and air temperatures the same) with low (5%) relative humidity and low wind speed (0.1 m/s), as is often the case in metabolic chamber experiments. This example uses parameters for the Australian budgerigar Melopsittacus undulatus and compares it against data from Weathers & Schoenbaechler (1976).
Weathers, W.W. & Schoenbaechler, D.C. (1976) Regulation of body temperature in the Budgerygah, Melopsittacus undulatus. Australian Journal of Zoology, 24, 39–47.
library(NicheMapR) # environment TAs <- seq(0, 50, 1) # air temperature (°C) VEL <- 0.1 # wind speed (m/s) vd <- WETAIR(rh = 30, db = 40)$vd # Weathers and Schoenbaechler had 16.7 mm Hg # above 40 °C = 30% RH at 40 °C vd_sat <- WETAIR(rh = 100, db = TAs)$vd # Weathers and Schoenbaechler had 16.7 mm Hg # above 40 °C = 30% RH at 40 °C exp_rh <- vd / vd_sat * 100 exp_rh[exp_rh > 100] <- 100 exp_rh[TAs < 30] <- 15 hum <- exp_rh # core temperature TC <- 38 # core temperature (°C) TC_MAX <- 43 # maximum core temperature (°C) TC_INC <- 0.25 # increment by which TC is elevated (°C) # size and shape AMASS <- 0.0337 # mass (kg) SHAPE_B <- 1.1 # start off near to a sphere (-) SHAPE_B_MAX <- 5 # maximum ratio of length to width/depth UNCURL <- 0.1 # allows the animal to uncurl to SHAPE_B_MAX, the value being the increment # SHAPE_B is increased per iteration SHAPE <- 4 # use ellipsoid geometry SAMODE <- 1 # use bird surface area relations (2 is mammal, 0 is based on shape specified # in GEOM) # feather properties DHAIRD <- 30E-06 # hair diameter, dorsal (m) DHAIRV <- 30E-06 # hair diameter, ventral (m) LHAIRD <- 23.1E-03 # hair length, dorsal (m) LHAIRV <- 22.7E-03 # hair length, ventral (m) ZFURD <- 5.9E-03 # fur depth, dorsal (m) ZFURV <- 5.7E-03 # fur depth, ventral (m) RHOD <- 5000E+04 # hair density, dorsal (1/m2) RHOV <- 5000E+04 # hair density, ventral (1/m2) REFLD <- 0.248 # fur reflectivity dorsal (fractional, 0-1) REFLV <- 0.351 # fur reflectivity ventral (fractional, 0-1) # physiological responses PCTWET <- 0.5 # base skin wetness (%) PCTWET_MAX <- 5 # maximum skin wetness (%) PCTWET_INC <- 0.25 # intervals by which skin wetness is increased (%) Q10s <- rep(1, length(TAs)) Q10s[TAs >= TC_MAX] <- 2 # assuming Q10 effect kicks in only after air temp rises above TC_MAX QBASAL <- 10 ^ (-1.461 + 0.669 * log10(AMASS * 1000)) # basal heat generation (W) DELTAR <- 5 # offset between air temperature and breath (°C) EXTREF <- 25 # O2 extraction efficiency (%) PANT_INC <- 0.1 # turns on panting, the value being the increment by which the panting multiplier # is increased up to the maximum value, PANT_MAX PANT_MAX <- 15 # maximum panting rate - multiplier on air flow through the lungs above # that determined by metabolic rate PANT_MULT <- 1 # multiplier on basal metabolic rate at maximum panting level ptm <- proc.time() # start timing endo.out <- lapply(1:length(TAs), function(x){endoR(TA = TAs[x], VEL = VEL, TC = TC, TC_MAX = TC_MAX, RH = hum[x], AMASS = AMASS, SHAPE = SHAPE, SHAPE_B = SHAPE_B, SHAPE_B_MAX = SHAPE_B_MAX, PCTWET = PCTWET, PCTWET_INC = PCTWET_INC, PCTWET_MAX = PCTWET_MAX, Q10 = Q10s[x], QBASAL = QBASAL, DELTAR = DELTAR, DHAIRD = DHAIRD, DHAIRV = DHAIRV, LHAIRD = LHAIRD, LHAIRV = LHAIRV, ZFURD = ZFURD, ZFURV = ZFURV, RHOD = RHOD, RHOV = RHOV, REFLD = REFLD, TC_INC = TC_INC, PANT_INC = PANT_INC, PANT_MAX = PANT_MAX, EXTREF = EXTREF, UNCURL = UNCURL, SAMODE = SAMODE, PANT_MULT = PANT_MULT)}) # run endoR across environments proc.time() - ptm # stop timing # extract the output endo.out1 <- do.call("rbind", lapply(endo.out, data.frame)) # thermoregulation output treg <- endo.out1[, grep(pattern = "treg", colnames(endo.out1))] colnames(treg) <- gsub(colnames(treg), pattern = "treg.", replacement = "") # morphometric output morph <- endo.out1[, grep(pattern = "morph", colnames(endo.out1))] colnames(morph) <- gsub(colnames(morph), pattern = "morph.", replacement = "") # heat balance enbal <- endo.out1[, grep(pattern = "enbal", colnames(endo.out1))] colnames(enbal) <- gsub(colnames(enbal), pattern = "enbal.", replacement = "") # mass aspects masbal <- endo.out1[, grep(pattern = "masbal", colnames(endo.out1))] colnames(masbal) <- gsub(colnames(masbal), pattern = "masbal.", replacement = "") QGEN <- enbal$QGEN # metabolic rate (W) H2O <- masbal$H2OResp_g + masbal$H2OCut_g # g/h water evaporated TFA_D <- treg$TFA_D # dorsal fur surface temperature TFA_V <- treg$TFA_V # ventral fur surface temperature TskinD <- treg$TSKIN_D # dorsal skin temperature TskinV <- treg$TSKIN_V # ventral skin temperature TCs <- treg$TC # core temperature par(mfrow = c(2, 2)) par(oma = c(2, 1, 2, 2) + 0.1) par(mar = c(3, 3, 1.5, 1) + 0.1) par(mgp = c(2, 1, 0)) plot(QGEN ~ TAs, type = 'l', ylab = 'metabolic rate, W', xlab = expression("air temperature, "*~degree*C*""), ylim = c(0.2, 1.2)) points(Weathers1976Fig1$Tair, Weathers1976Fig1$mlO2gh * 20.1 / 3600 * (AMASS * 1000), pch = 16, col = 2) legend(x = 30, y = 1.2, legend = c("observed", "predicted"), col = c("red", "black"), lty = c(NA, 1), bty = "n", pch = c(16, NA)) plot(H2O ~ TAs, type = 'l', ylab = 'water loss, g/h', xlab = expression("air temperature, "*~degree*C*""), ylim = c(0, 1.5)) points(masbal$H2OResp_g ~ TAs, type = 'l', lty = 2) points(masbal$H2OCut_g ~ TAs, type = 'l', lty = 2, col = 'blue') legend(x = 3, y = 1.5, legend = c("total (obs)", "total (pred)", "respiratory", "cutaneous"), col = c("red", "black", "black", "blue"), lty = c(NA, 1, 2, 2), bty = "n", pch = c(16, NA, NA, NA)) points(Weathers1976Fig3$Tair, Weathers1976Fig3$mgH2Ogh * AMASS, pch = 16, col = 2) plot(TFA_D ~ TAs, type = 'l', col = 'grey', ylab = expression("feather, skin and core temperature, "*~degree*C*""), xlab = expression("air temperature, "*~degree*C*""), ylim = c(10, 50)) points(TFA_V ~ TAs, type = 'l', col = 'grey', lty = 2) points(TskinD ~ TAs, type = 'l', col = 'orange') points(TskinV ~ TAs, type = 'l', col = 'orange', lty = 2) points(TCs ~ TAs, type = 'l', col = 'red') legend(x = 30, y = 33, legend = c("core (obs)", "core (pred)", "skin dorsal", "skin ventral", "feathers dorsal", "feathers ventral"), col = c("red", "red", "orange", "orange", "grey", "grey"), lty = c(NA, 1, 1, 2, 1, 2), bty = "n", pch = c(16, NA, NA, NA, NA, NA)) points(Weathers1976Fig2$Tair, Weathers1976Fig2$Tb, pch = 16, col = 2) plot(masbal$AIR_L * 1000 / 60 ~ TAs, ylim = c(0, 250), lty = 1, xlim = c(-5, 50), ylab = "ml air / min", xlab=expression("air temperature, "*~degree*C*""), type = 'l') legend(x = 0, y = 250, legend = c("observed", "predicted"), col = c("red", "black"), lty = c(NA, 1), bty = "n", pch = c(16, NA)) points(Weathers1976Fig5$breaths_min * (13.2 * AMASS ^ 1.08) * ((Weathers1976Fig5$Tair + 273.15) / 273.15) ~ Weathers1976Fig5$Tair, col = 2, pch = 16) # tidal volume allometry from Lasiewski, R. C., and W. A. Calder. 1971, correcting volume according to PV = nRT equation, where V_2 = T_2 * V_1 / T_2, and T_1 is at STP, so 0 °C
In this final example, the microclimate model is run for a location in central Australia, under unshaded conditions, and the then the relevant outputs are sent into the endotherm model along with the same animal parameters as above.
library(NicheMapR) loc <- c(131.05, -22.75) Usrhyt <- 0.07 maxshade <- 100 micro <- micro_global(loc = loc, Usrhyt = Usrhyt, maxshade = maxshade) metout <- as.data.frame(micro$metout) # unshaded above-ground conditions soil <- as.data.frame(micro$soil) # unshaded below-ground soil temperatures shadmet <- as.data.frame(micro$shadmet) # shaded above-ground conditions shadsoil <- as.data.frame(micro$shadsoil) # shaded below-ground soil temperatures dates <- micro$dates TAs <- metout$TALOC # air temperatures at height of animal (°C) TAREFs <- metout$TAREF # air temperatures at reference height (°C) TSKYs <- metout$TSKYC # sky temperatures (°C) TGRDs <- soil$D0cm # surface temperatures (°C) VELs <- metout$VLOC # wind speeds at animal height (m/s) RHs <- metout$RHLOC # relative humidity at animal height (%) QSOLRs <- metout$SOLR # solar radiation (W/m2) Zs <- metout$ZEN # zenith angle of the sun (degrees) ELEV <- micro$elev # elevation (m) ABSSB <- 1 - micro$REFL # substrate solar absorptivity (%) # core temperature TC <- 38 # core temperature (°C) TC_MAX <- 43 # maximum core temperature (°C) TC_INC <- 0.25 # increment by which TC is elevated (°C) # size and shape AMASS <- 0.0337 # mass (kg) SHAPE <- 4 # use ellipsoid geometry SHAPE_B <- 1.1 # start off near to a sphere (-) SHAPE_B_MAX <- 5 # maximum ratio of length to width/depth UNCURL <- 0.1 # allows the animal to uncurl to SHAPE_B_MAX, the value being the increment # SHAPE_B is increased per iteration # feather properties DHAIRD <- 30E-06 # hair diameter, dorsal (m) DHAIRV <- 30E-06 # hair diameter, ventral (m) LHAIRD <- 23.1E-03 # hair length, dorsal (m) LHAIRV <- 22.7E-03 # hair length, ventral (m) ZFURD <- 5.9E-03 # fur depth, dorsal (m) ZFURV <- 5.7E-03 # fur depth, ventral (m) RHOD <- 5000E+04 # hair density, dorsal (1/m2) RHOV <- 5000E+04 # hair density, ventral (1/m2) REFLD <- 0.248 # fur reflectivity dorsal (fractional, 0-1) REFLV <- 0.351 # fur reflectivity ventral (fractional, 0-1) # physiological responses PCTWET <- 0.1 # base skin wetness (%) PCTWET_MAX <- 0.1 # maximum skin wetness (%) PCTWET_INC <- 0.25 # intervals by which skin wetness is increased (%) Q10 <- 1 # Q10 effect of body temperature on metabolic rate (-) QBASAL <- 10 ^ (-1.461 + 0.669 * log10(AMASS * 1000)) # basal heat generation (W) DELTAR <- 5 # offset between air temperature and breath (°C) EXTREF <- 25 # O2 extraction efficiency (%) PANT_INC <- 0.1 # turns on panting, the value being the increment by which the panting # multiplier is increased up to the maximum value, PANT_MAX PANT_MAX <- 15 # maximum panting rate - multiplier on air flow through the lungs above # that determined by metabolic rate PANT_MULT <- 1 # multiplier on basal metabolic rate at maximum panting level # run the model ptm <- proc.time() # start timing endo.out <- lapply(1:length(TAs), function(x){endoR(TA = TAs[x], TAREF = TAREFs[x], TSKY = TSKYs[x], TGRD = TGRDs[x], VEL = VELs[x], RH = RHs[x], QSOLR = QSOLRs[x], Z = Zs[x], ELEV = ELEV, ABSSB = ABSSB, TC = TC, TC_MAX = TC_MAX, AMASS = AMASS, SHAPE = SHAPE, SHAPE_B = SHAPE_B, SHAPE_B_MAX = SHAPE_B_MAX, PCTWET = PCTWET, PCTWET_INC = PCTWET_INC, Q10 = Q10, QBASAL = QBASAL, DELTAR = DELTAR, DHAIRD = DHAIRD, DHAIRV = DHAIRV, LHAIRD = LHAIRD, LHAIRV = LHAIRV, ZFURD = ZFURD, ZFURV = ZFURV, RHOD = RHOD, RHOV = RHOV, REFLD = REFLD, TC_INC = TC_INC, PANT_INC = PANT_INC, PANT_MAX = PANT_MAX, EXTREF = EXTREF, UNCURL = UNCURL, SAMODE = SAMODE, SHADE = 0, PANT_MULT = PANT_MULT)}) proc.time() - ptm # end timing # extract the output endo.out1 <- do.call("rbind", lapply(endo.out, data.frame)) # thermoregulation output treg <- endo.out1[, grep(pattern = "treg", colnames(endo.out1))] colnames(treg) <- gsub(colnames(treg), pattern = "treg.", replacement = "") # morphometric output morph <- endo.out1[, grep(pattern = "morph", colnames(endo.out1))] colnames(morph) <- gsub(colnames(morph), pattern = "morph.", replacement = "") # heat balance enbal <- endo.out1[, grep(pattern = "enbal", colnames(endo.out1))] colnames(enbal) <- gsub(colnames(enbal), pattern = "enbal.", replacement = "") # mass aspects masbal <- endo.out1[, grep(pattern = "masbal", colnames(endo.out1))] colnames(masbal) <- gsub(colnames(masbal), pattern = "masbal.", replacement = "") # extract variables for plotting QGEN <- enbal$QGEN # metabolic rate (W) H2O <- masbal$H2OResp_g + masbal$H2OCut_g # g/h water evaporated TFA_D <- treg$TFA_D # dorsal fur surface temperature TFA_V <- treg$TFA_V # ventral fur surface temperature TskinD <- treg$TSKIN_D # dorsal skin temperature TskinV <- treg$TSKIN_V # ventral skin temperature TCs <- treg$TC # core temperature SkinW <- treg$SKINWET # skin wetness (%) Pant <- treg$PANT # panting multiplier (-) # plot the results par(mfrow = c(2, 2)) par(oma = c(2, 1, 2, 2) + 0.1) par(mar = c(3, 3, 1.5, 1) + 0.1) par(mgp = c(2, 1, 0)) plot(QGEN ~ dates, type = 'l', ylab = 'metabolic rate, W', xlab = 'time', ylim = c(0, QBASAL * 5)) plot(H2O ~ dates, type = 'l', ylab = 'water loss, g / h', xlab = 'time', ylim = c(0, 2)) points(masbal$H2OResp_g ~ dates, type = 'l', lty = 2) points(masbal$H2OCut_g ~ dates, type = 'l', lty = 2, col = 'blue') legend(x = 4, y = 2, legend = c("total", "respiratory", "cutaneous"), col = c("black", "black", "blue"), lty = c(1, 2, 2), bty = "n") plot(TFA_D ~ dates, type = 'l', col = 'grey', ylab = 'temperature, °C', xlab = 'time', ylim = c(0, 60)) points(TFA_V ~ dates, type = 'l', col = 'grey', lty = 2) points(TskinD ~ dates, type = 'l', col = 'orange') points(TskinV ~ dates, type = 'l', col = 'orange', lty = 2) points(TCs ~ dates, type = 'l', col = 'red') legend(x = 1, y = 65, legend = c("core", "skin dorsal", "skin ventral", "feathers dorsal", "feathers ventral"), col = c("red", "orange", "orange", "grey", "grey"), lty = c(1, 1, 2, 1, 2), bty = "n", ncol = 2) plot((H2O / (AMASS * 1000)) * 100 ~ dates, type = 'l', ylab = 'H2O loss, % body mass / h', xlab = 'time', ylim = c(0, 5))
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