TS Converted from R

src/fwi/C6calc.ts

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+/**
+ * C-6 Conifer Plantation Fire Spread Calculator
+ *
+ * Calculate C6 (Conifer plantation) Fire Spread. C6 is a special
+ * case, and thus has its own function. To calculate C6 fire spread, this
+ * function also calculates and can return ROS, CFB, RSC, or RSI by specifying
+ * in the option parameter.
+ * All variables names are laid out in the same manner as Forestry Canada Fire
+ * Danger Group (FCFDG) (1992). Development and Structure of the Canadian
+ * Forest Fire Behavior Prediction System." Technical Report ST-X-3, Forestry
+ * Canada, Ottawa, Ontario.
+ *
+ * @param FUELTYPE    The Fire Behaviour Prediction FuelType
+ * @param ISI         Initial Spread Index
+ * @param BUI         Buildup Index
+ * @param FMC         Foliar Moisture Content
+ * @param SFC         Surface Fuel Consumption
+ * @param CBH         Crown Base Height
+ * @param ROS         Rate of Spread
+ * @param CFB         Crown Fraction Burned
+ * @param RSC         Crown Fire Spread Rate (m/min)
+ * @param option      Which variable to calculate ("ROS", "RSC", "RSI", or "CFB" (the default).)
+ *
+ * @return ROS, CFB, RSC or RSI depending on which option was selected
+ */
+
+import { criticalSurfaceIntensity, surfaceFireRateOfSpread, crownFractionBurned } from "./CFBcalc"
+import { buildupEffect } from "./buildup_effect";
+
+function intermediateSurfaceRateOfSpreadC6(ISI: number): number {
+    // Eq. 62 (FCFDG 1992) Intermediate surface fire spread rate
+    return 30 * Math.pow(1 - Math.exp(-0.08 * ISI), 3.0);
+}
+
+function surfaceRateOfSpreadC6(RSI: number, BUI: number): number {
+    // Eq. 63 (FCFDG 1992) Surface fire spread rate (m/min)
+    return RSI * buildupEffect("C6", BUI);
+}
+
+function crownRateOfSpreadC6(ISI: number, FMC: number): number {
+    // Average foliar moisture effect
+    const FMEavg = 0.778;
+    // Eq. 59 (FCFDG 1992) Crown flame temperature (degrees K)
+    const tt = 1500 - 2.75 * FMC;
+    // Eq. 60 (FCFDG 1992) Head of ignition (kJ/kg)
+    const H = 460 + 25.9 * FMC;
+    // Eq. 61 (FCFDG 1992) Average foliar moisture effect
+    const FME = Math.pow(1.5 - 0.00275 * FMC, 4.0) / (460 + 25.9 * FMC) * 1000;
+    // Eq. 64 (FCFDG 1992) Crown fire spread rate (m/min)
+    return 60 * (1 - Math.exp(-0.0497 * ISI)) * FME / FMEavg;
+}
+
+function crownFractionBurnedC6(RSC: number, RSS: number, RSO: number): number {
+    return (RSC > RSS) && (RSS > RSO) ? crownFractionBurned(RSS, RSO) : 0;
+}
+
+function rateOfSpreadC6(RSC: number, RSS: number, CFB: number): number {
+    // Eq. 65 (FCFDG 1992) Calculate Rate of spread (m/min)
+    return RSC > RSS ? RSS + CFB * (RSC - RSS) : RSS;
+}
+
+export function C6calc(
+    FUELTYPE: string, 
+    ISI: number, 
+    BUI: number, 
+    FMC: number, 
+    SFC: number, 
+    CBH: number, 
+    option: string = "CFB"
+): number {
+    // This should be validated for the FUELTYPE
+    // if (FUELTYPE !== "C6") {
+    //     throw new Error("Invalid FUELTYPE for C6 calculation");
+    // }
+
+    const RSI = intermediateSurfaceRateOfSpreadC6(ISI);
+    if (option === "RSI") {
+        console.warn("Deprecated: intermediateSurfaceRateOfSpreadC6");
+        return RSI;
+    }
+
+    const RSC = crownRateOfSpreadC6(ISI, FMC);
+    if (option === "RSC") {
+        console.warn("Deprecated: crownRateOfSpreadC6");
+        return RSC;
+    }
+
+    const RSS = surfaceRateOfSpreadC6(RSI, BUI);
+    const CSI = criticalSurfaceIntensity(FMC, CBH);
+    const RSO = surfaceFireRateOfSpread(CSI, SFC);
+    const CFB = crownFractionBurnedC6(RSC, RSS, RSO);
+    if (option === "CFB") {
+        console.warn("Deprecated: crownFractionBurnedC6");
+        return CFB;
+    }
+
+    console.warn("Deprecated: rateOfSpreadC6");
+    const ROS = rateOfSpreadC6(RSC, RSS, CFB);
+    return ROS;
+}
+
+// Exporting functions for external usage
+export { intermediateSurfaceRateOfSpreadC6, surfaceRateOfSpreadC6, crownRateOfSpreadC6, crownFractionBurnedC6, rateOfSpreadC6 };

src/fwi/CFBcalc.ts

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+/**
+ * Crown Fraction Burned Calculator
+ *
+ * Calculate Calculate Crown Fraction Burned. To calculate CFB, we
+ * also need to calculate Critical surface intensity (CSI), and Surface fire
+ * rate of spread (RSO). The value of each of these equations can be returned
+ * to the calling function without unnecessary additional calculations.
+ *
+ * All variables names are laid out in the same manner as Forestry Canada Fire
+ * Danger Group (FCFDG) (1992). Development and Structure of the Canadian
+ * Forest Fire Behavior Prediction System." Technical Report ST-X-3, Forestry
+ * Canada, Ottawa, Ontario.
+ *
+ * @param FUELTYPE The Fire Behaviour Prediction FuelType
+ * @param FMC      Foliar Moisture Content
+ * @param SFC      Surface Fuel Consumption
+ * @param CBH      Crown Base Height
+ * @param ROS      Rate of Spread
+ * @param option   Which variable to calculate ("ROS", "RSC", "RSI", or "CFB" (the default).)
+ * @returns        CFB, CSI, RSO depending on which option was selected.
+ */
+
+/**
+ * Calculate Critical Surface Intensity (CSI).
+ *
+ * @param FMC Foliar Moisture Content
+ * @param CBH Crown Base Height
+ * @returns   Critical Surface Intensity (CSI)
+ */
+function criticalSurfaceIntensity(FMC: number, CBH: number): number {
+    return 0.001 * (Math.pow(CBH, 1.5)) * Math.pow((460 + 25.9 * FMC), 1.5);
+}
+
+/**
+ * Calculate Surface Fire Rate of Spread (RSO).
+ *
+ * @param CSI Critical Surface Intensity
+ * @param SFC Surface Fuel Consumption
+ * @returns   Surface Fire Rate of Spread (RSO)
+ */
+function surfaceFireRateOfSpread(CSI: number, SFC: number): number {
+    return CSI / (300 * SFC);
+}
+
+/**
+ * Calculate Crown Fraction Burned (CFB).
+ *
+ * @param ROS Rate of Spread
+ * @param RSO Surface Fire Rate of Spread
+ * @returns   Crown Fraction Burned (CFB)
+ */
+function crownFractionBurned(ROS: number, RSO: number): number {
+    return ROS > RSO ? 1 - Math.exp(-0.23 * (ROS - RSO)) : 0;
+}
+
+/**
+ * Main function to calculate various fire behavior metrics.
+ *
+ * @param FUELTYPE The Fire Behaviour Prediction FuelType
+ * @param FMC      Foliar Moisture Content
+ * @param SFC      Surface Fuel Consumption
+ * @param ROS      Rate of Spread
+ * @param CBH      Crown Base Height
+ * @param option   Which variable to calculate ("ROS", "RSC", "RSI", or "CFB" (the default).)
+ * @returns        CFB, CSI, RSO depending on which option was selected.
+ */
+function CFBcalc(
+    FUELTYPE: string, 
+    FMC: number, 
+    SFC: number, 
+    ROS: number, 
+    CBH: number, 
+    option: string = "CFB"
+): number {
+    const CSI = criticalSurfaceIntensity(FMC, CBH);
+
+    if (option === "CSI") {
+        console.warn("Deprecated: criticalSurfaceIntensity");
+        return CSI;
+    }
+
+    const RSO = surfaceFireRateOfSpread(CSI, SFC);
+
+    if (option === "RSO") {
+        console.warn("Deprecated: surfaceFireRateOfSpread");
+        return RSO;
+    }
+
+    const CFB = crownFractionBurned(ROS, RSO);
+    console.warn("Deprecated: crownFractionBurned");
+    return CFB;
+}
+
+// Export the function for external usage
+export { CFBcalc, criticalSurfaceIntensity, surfaceFireRateOfSpread, crownFractionBurned };