{

#region fields

private static readonly double[] Lf = { 1.6, 1.6, 1.6, 0.9, 3.8, 5.8, 6.4, 5.0, 2.4, 0.4, -1.6, -1.6 };

private static readonly double[] Le = { 6.5, 7.5, 9.0, 12.8, 13.9, 13.9, 12.4, 10.9, 9.2, 8.0, 7.0, 6.0 };

#endregion

#region private methods

private static void CalculateDailyFireWeather(List<ClimateRecord> yearRecords)

{

double fineFuelMoistureCodeYesterday = ConfigParameters.FineFuelMoistureCode_Yesterday;

double duffMoistureCodeYesterday = ConfigParameters.DuffMoistureCode_Yesterday;

double droughtCodeYesterday = ConfigParameters.DroughtCode_Yesterday;

if (ConfigParameters.SpringStart < 0 || ConfigParameters.SpringStart >= yearRecords.Count ||

ConfigParameters.WinterStart < 0 || ConfigParameters.WinterStart >= yearRecords.Count ||

ConfigParameters.SpringStart > ConfigParameters.WinterStart) return;

// loop over days from SpringStart to WinterStart

for (var d = ConfigParameters.SpringStart; d < ConfigParameters.WinterStart; ++d)

{

var record = yearRecords[d];

var mo = Calculate_mo(fineFuelMoistureCodeYesterday);

var Ed = Calculate_Ed(record.RH, record.Temp);

var Ew = Calculate_Ew(record.RH, record.Temp);

var ko = Calculate_ko(record.RH, record.WindSpeed);

var kd = Calculate_kd(ko, record.Temp);

var kl = Calculate_kl(record.RH, record.WindSpeed);

var kw = Calculate_kw(kl, record.Temp);

var m = Calculate_m(mo, Ed, kd, Ew, kw);

var re = Calculate_re(record.Precip);

var Mo = Calculate_Mo(duffMoistureCodeYesterday);

var b = Calculate_b(duffMoistureCodeYesterday);

var Mr = Calculate_Mr(re, b, Mo);

var Pr = Calculate_Pr(Mr);

var month = Climate.MonthOfYear(d);

var K = Calculate_K(record.Temp, record.RH, Le[month]);

var duffMoistureCode = Calculate_DuffMoistureCode(record.Precip, Pr, K, duffMoistureCodeYesterday);

var rd = Calculate_rd(record.Precip);

var Qo = Calculate_Qo(droughtCodeYesterday);

var Qr = Calculate_Qr(Qo, rd);

var Dr = Calculate_Dr(Qr);

var V = Calculate_V(record.Temp, Lf[month]);

var droughtCode = Calculate_DroughtCode(record.Precip, Dr, V, droughtCodeYesterday);

var windFunction_ISI = Calculate_WindFunction_ISI(record.WindSpeed);

var fineFuelMoistureFunction_ISI = Calculate_FineFuelMoistureFunction_ISI(m);

var initialSpreadIndex = Calculate_InitialSpreadIndex(windFunction_ISI, fineFuelMoistureFunction_ISI);

var buildUpIndex = Calculate_BuildUpIndex(duffMoistureCode, droughtCode);

var fD = Calculate_fD(buildUpIndex);

var B = Calculate_B(initialSpreadIndex, fD);

record.DuffMoistureCode = duffMoistureCodeYesterday = duffMoistureCode;

record.DroughtCode = droughtCodeYesterday = droughtCode;

record.BuildUpIndex = buildUpIndex;

record.FineFuelMoistureCode = fineFuelMoistureCodeYesterday = Calculate_FineFuelMoistureCode(m);

record.FireWeatherIndex = Calculate_FireWeatherIndex(B);

}

}

private static double Calculate_mo(double fineFuelMoistureCode) => 147.2 * (101.0 - fineFuelMoistureCode) / (59.5 + fineFuelMoistureCode); //This used to be an explicit seed value for FFMC

private static double Calculate_Ed(double rh, double temp) => 0.942 * Math.Pow(rh, 0.679) + 11.0 * Math.Exp((rh - 100.0) / 10.0) + 0.18 * (21.1 - temp) * (1.0 - Math.Exp(-0.115 * rh));

private static double Calculate_Ew(double rh, double temp) => 0.618 * Math.Pow(rh, 0.753) + 10.0 * Math.Exp((rh - 100.0) / 10.0) + 0.18 * (21.1 - temp) * (1.0 - Math.Exp(-0.115 * rh)); //selfs

private static double Calculate_ko(double rh, double windSpeed) => 0.424 * (1.0 - Math.Pow(rh / 100.0, 1.7)) + 0.0694 * Math.Pow(windSpeed, 0.5) * (1.0 - Math.Pow((rh / 100.0), 8));

private static double Calculate_kd(double ko, double temp) => ko * 0.581 * Math.Exp(0.0365 * temp);

private static double Calculate_kl(double rh, double windSpeed) => 0.424 * (1.0 - Math.Pow((100.0 - rh) / 100.0, 1.7)) + 0.0694 * Math.Pow(windSpeed, 0.5) * (1.0 - Math.Pow(((100.0 - rh) / 100.0), 8));

private static double Calculate_kw(double kl, double temp) => kl * 0.581 * Math.Exp(0.0365 * temp);

private static double Calculate_m(double mo, double Ed, double kd, double Ew, double kw)

{

if (mo > Ed)

return Ed + (mo - Ed) * Math.Pow(10.0, -kd);

return (mo < Ed && mo < Ew) ? (Ew - mo) * Math.Pow(10.0, -kw) : mo;

}

private static double Calculate_FineFuelMoistureCode(double m) => Math.Min(100.0, 59.5 * (250.0 - m) / (147.2 + m));

private static double Calculate_re(double precip) => precip > 1.5 ? 0.92 * precip - 1.27 : 0.0;

private static double Calculate_Mo(double duffMoistureCode) => 20.0 + Math.Exp(5.6348 - duffMoistureCode / 43.43);

private static double Calculate_b(double duffMoistureCode)

{

if (duffMoistureCode <= 33.0)

{

return 100.0 / (0.5 + 0.3 * duffMoistureCode);

}

if (duffMoistureCode > 65.0)

{

return 6.2 * Math.Log(duffMoistureCode) - 17.2;

}

return 14.0 - 1.3 * Math.Log(duffMoistureCode);

}

private static double Calculate_Mr(double re, double b, double Mo) => Mo + 1000.0 * re / (48.77 + b * re);

private static double Calculate_Pr(double Mr) => Math.Max(0.0, 244.72 - 43.43 * Math.Log(Mr - 20.0));

private static double Calculate_K(double temp, double rh, double Le) => temp < -1.1 ? 0.0 : 1.894 * (temp + 1.1) * (100.0 - rh) * Le * Math.Pow(10.0, -6.0);

private static double Calculate_DuffMoistureCode(double precip, double Pr, double K, double duffMoistureCode) => precip > 1.5 ? Pr + 100.0 * K : duffMoistureCode + 100.0 * K;

private static double Calculate_rd(double precip) => precip > 2.8 ? 0.83 * precip - 1.27 : 0.0;

private static double Calculate_Qo(double droughtCode) => 800.0 * Math.Exp(-droughtCode / 400.0);

private static double Calculate_Qr(double Qo, double rd) => Qo + 3.937 * rd;

private static double Calculate_Dr(double Qr) => Math.Max(0.0, 400.0 * Math.Log(800.0 / Qr));

private static double Calculate_V(double temp, double Lf) => temp < -2.8 ? Lf : 0.36 * (temp + 2.8) + Lf;

private static double Calculate_DroughtCode(double precip, double Dr, double V, double droughtCodeYesterday) => precip > 2.8 ? Dr + 0.5 * V : droughtCodeYesterday + 0.5 * V;

private static double Calculate_WindFunction_ISI(double windSpeed) => Math.Exp(0.05039 * windSpeed);

private static double Calculate_FineFuelMoistureFunction_ISI(double m) => 91.9 * Math.Exp(-0.1386 * m) * (1.0 + Math.Pow(m, 5.31) / (4.93 * Math.Pow(10.0, 7.0)));

private static double Calculate_InitialSpreadIndex(double windFunction_ISI, double fineFuelMoistureFunction_ISI) => 0.208 * windFunction_ISI * fineFuelMoistureFunction_ISI;

private static double Calculate_BuildUpIndex(double duffMoistureCode, double droughtCode) => duffMoistureCode <= 0.4 * droughtCode ? 0.8 * duffMoistureCode * droughtCode / (duffMoistureCode + 0.4 * droughtCode) : duffMoistureCode - (1.0 - 0.8 * droughtCode / (duffMoistureCode + 0.4 * droughtCode)) * (0.92 + 0.0114 * Math.Pow(duffMoistureCode, 1.7));

private static double Calculate_fD(double buildUpIndex) => buildUpIndex <= 80.0 ? 0.626 * Math.Pow(buildUpIndex, 0.809) + 2.0 : 1000.0 / (25.0 + 108.64 * Math.Exp(-0.023 * buildUpIndex));

private static double Calculate_B(double initialSpreadIndex, double fD) => 0.1 * initialSpreadIndex * fD;

private static double Calculate_FireWeatherIndex(double B) => B > 1.0 ? Math.Exp(2.72 * Math.Pow(0.434 * Math.Log(B), 0.647)) : B;

#endregion