Small complement to the "filter dev" documentation. A first implementation of...

Small complement to the "filter dev" documentation. A first implementation of the wet globe temperature has been contributed, but this is NOT usable yet (a few coefficients still must be set for the convective heat transfer coefficient).

meteoio/MainPage.h

@@ -355,10 +355,11 @@ namespace mio {
  *    @endcode
  * -# Adding the created implementation file to meteoFilters/CMakeLists.txt in a similar way as for the other
  *    filters
- * -# Adding the filter in the processing loop, in BlockFactory::getBlock(), by adding three lines similar to:
+ * -# Adding the filter in the processing loop, in meteoFilters/ProcessingBlock.cc in the BlockFactory::getBlock()
+ * method by adding three lines similar to:
  *    @code
  *     else if (blockname == "MIN_MAX"){
- *     		return new FilterMinMax(vec_args);
+ *     		return new FilterMinMax(vec_args, blockname);
  * 	}
  *    @endcode
  *    The key (here the string "MIN_MAX") is the key that the user will put in his io.ini to select the processing block.

meteoio/meteoLaws/Atmosphere.cc

@@ -107,6 +107,32 @@ double Atmosphere::wetBulbTemperature(const double& T, const double& RH, const d
 	return ( T - (RH*Vp - Vp) * mixing_ratio * L / p / Cst::specific_heat_air );
 }
 
+/**
+* @brief Black Globe Temperature.
+* This is an estimation of the black globe temperature based on physical modeling as in
+* V. E. Dimiceli, S. F. Piltz and S. A. Amburn, <i>"Estimation of Black Globe Temperature for Calculation of the Wet Bulb Globe Temperature Index"</i> in World Congress on Engineering and Computer Science, <b>2</b>, 2011. 
+* @param TA air temperature (K)
+* @param RH relative humidity (between 0 and 1)
+* @param VW wind velocity (m/s)
+* @param iswr_dir direct solar SW radiation (W/m^2)
+* @param iswr_diff diffuse solar SW radiation (W/m^2)
+* @param cos_Z cosinus of the solar zenith angle
+* @return black globe temperature (K)
+*/
+double Atmosphere::blackGlobeTemperature(const double& TA, const double& RH, const double& VW, const double& iswr_dir, const double& iswr_diff, const double& cos_Z)
+{
+	const double a=1, b=1, c=1; //HACK: get real values!
+	
+	const double S = iswr_dir + iswr_diff;
+	const double h = a * pow(S, b) * pow(cos_Z, c);
+	const double emissivity = 0.575 * pow(RH*waterSaturationPressure(TA), 1./7.);
+	const double B = S * (iswr_dir/(4.*Cst::stefan_boltzmann*cos_Z) + 1.2/Cst::stefan_boltzmann*iswr_diff) + emissivity*Optim::pow4(TA);
+	const double C = h * pow(VW, 0.58) / 5.3865e-8;
+	
+	const double Tg = (B + C*TA + 7680000) / (C + 256000);
+	return Tg;
+}
+
 /**
 * @brief Wind log profile.
 * This is used to compute the equivalent wind speed at a different height.
@@ -182,6 +208,28 @@ double Atmosphere::heatIndex(const double& TA, const double& RH)
 	return C_TO_K(HI);
 }
 
+/**
+* @brief Wet Bulb Globe Temperature index.
+* This is an index aiming at expressing the human-perceived air temperature due to humidity, wind and radiation.
+* This is the foundation of ISO 7243 and is widely used for physical activity safety evaluation (for example for physical training).
+* @param TA air temperature (K)
+* @param RH relative humidity (between 0 and 1)
+* @param VW wind velocity (m/s)
+* @param iswr_dir direct solar SW radiation (W/m^2)
+* @param iswr_diff diffuse solar SW radiation (W/m^2)
+* @param cos_Z cosinus of the solar zenith angle
+* @param altitude altitude of the point where to perform the calculation
+* @return Heat index (K)
+*/
+double Atmosphere::WBGT_index(const double& TA, const double& RH, const double& VW, const double& iswr_dir, const double& iswr_diff, const double& cos_Z, const double& altitude)
+{
+	const double NWB = wetBulbTemperature(TA, RH, altitude);
+	const double GT = blackGlobeTemperature(TA, RH, VW, iswr_dir, iswr_diff, cos_Z);
+	const double DB = TA;
+	
+	return 0.7*NWB + 0.2*GT + 0.1*DB;
+}
+
 /**
 * @brief Standard water vapor saturation
 * @param T air temperature (K)

meteoio/meteoLaws/Atmosphere.h

@@ -38,10 +38,12 @@ class Atmosphere {
 		static double virtualTemperatureFactor(const double& e, const double& p);
 		static double waterVaporDensity(const double& Temperature, const double& VaporPressure);
 		static double wetBulbTemperature(const double& T, const double& RH, const double& altitude);
+		static double blackGlobeTemperature(const double& TA, const double& RH, const double& VW, const double& iswr_dir, const double& iswr_diff, const double& cos_Z);
 		static double windLogProfile(const double& v_ref, const double& z_ref, const double& z, const double& z0=0.03);
 
 		static double windChill(const double& TA, const double& VW);
 		static double heatIndex(const double& TA, const double& RH);
+		static double WBGT_index(const double& TA, const double& RH, const double& VW, const double& iswr_dir, const double& iswr_diff, const double& cos_Z, const double& altitude);
 
 		//clear sky emissivity
 		static double Brutsaert_emissivity(const double& RH, const double& TA);