heat_index_nws

ncl/ncl_entries/meteorology.ipynb

@@ -16,7 +16,8 @@
     "This section covers meteorology functions from NCL:\n",
     "\n",
     "- [dewtemp_trh](https://www.ncl.ucar.edu/Document/Functions/Built-in/dewtemp_trh.shtml)\n",
-    "- [daylight_fao56](https://www.ncl.ucar.edu/Document/Functions/Crop/daylight_fao56.shtml)"
+    "- [daylight_fao56](https://www.ncl.ucar.edu/Document/Functions/Crop/daylight_fao56.shtml)\n",
+    "- [heat_index_nws](https://www.ncl.ucar.edu/Document/Functions/Contributed/heat_index_nws.shtml)"
    ]
   },
   {
@@ -116,6 +117,80 @@
     "max_daylight(days_of_year, latitudes)"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## heat_index_nws\n",
+    "\n",
+    "NCL's `heat_index_nws` computes the heat index as calculated by the National Weather Service{footcite}`nws_heat_index`\n",
+    "\n",
+    "Default coefficients when temperature if greater 80°F and relative humidity is greater than 40%\n",
+    "\n",
+    "Alternate coefficients when temperature is between 70°F and 115°F and relative humidity less than 80%\n",
+    "\n",
+    "The equation for the heat index to match the NOAA National Weather Service table is derived from regression analysis, so the default coefficients have a degree of error up to ±1.3°F{footcite}`rothfusz_heat_index`"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### Grab and Go"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "array([85.3104587])"
+      ]
+     },
+     "execution_count": 9,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "# Input: Single Value\n",
+    "from geocat.comp import heat_index\n",
+    "\n",
+    "temp = 85  # Degrees Fahrenheit\n",
+    "rh = 45  # %\n",
+    "\n",
+    "heat_index(temp, rh)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 10,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "array([137.36135724, 135.8679973 ,  85.3104587 ])"
+      ]
+     },
+     "execution_count": 10,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "# Input: List/Array\n",
+    "from geocat.comp import heat_index\n",
+    "\n",
+    "temps = [104, 100, 85]  # Degrees Fahrenheit\n",
+    "rhs = [55, 65, 45]  # %\n",
+    "\n",
+    "heat_index(temps, rhs)"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -130,7 +205,8 @@
     "## Python Resources\n",
     "- [GeoCAT-comp `dewtemp` documentation](https://geocat-comp.readthedocs.io/en/latest/user_api/generated/geocat.comp.meteorology.dewtemp.html)\n",
     "- [Convert between different temperature scales in SciPy](https://docs.scipy.org/doc/scipy/reference/generated/scipy.constants.convert_temperature.html)\n",
-    "- [GeoCAT-comp `max_daylight` Documentation](https://geocat-comp.readthedocs.io/en/latest/user_api/generated/geocat.comp.meteorology.max_daylight.html)\n",
+    "- [GeoCAT-comp `max_daylight` documentation](https://geocat-comp.readthedocs.io/en/latest/user_api/generated/geocat.comp.meteorology.max_daylight.html)\n",
+    "- [GeoCAT-comp `heat_index` documentation](https://geocat-comp.readthedocs.io/en/stable/user_api/generated/geocat.comp.meteorology.heat_index.html)\n",
     "\n",
     "## Additional Reading\n",
     "- [NOAA: Dew Point vs. Humidity](https://www.weather.gov/arx/why_dewpoint_vs_humidity)"

ncl/ncl_index/ncl-index-table.csv

@@ -45,3 +45,4 @@ NCL Function,Description,Python Equivalent,Notes
 `round <https://www.ncl.ucar.edu/Document/Functions/Built-in/round.shtml>`__,"Rounds a float or double variable to the nearest whole number","``round()`` or ``numpy.round()``",`example notebook <../ncl_entries/general_applied_math.ipynb#decimalplaces-round>`__
 `daylight_fao56 <https://www.ncl.ucar.edu/Document/Functions/Crop/daylight_fao56.shtml>`__," Compute maximum number of daylight hours as described in FAO 56","``geocat.comp.meteorology.max_daylight()``",`example notebook <../ncl_entries/meteorology.ipynb#daylight-fao56>`__
 `dewtemp_trh <https://www.ncl.ucar.edu/Document/Functions/Built-in/dewtemp_trh.shtml>`__,"Calculates the dew point temperature given temperature and relative humidity","``geocat.comp.dewtemp()``",`example notebook <../ncl_entries/meteorology.ipynb#dewtemp-trh>`__
+`heat_index_nws <https://www.ncl.ucar.edu/Document/Functions/Contributed/heat_index_nws.shtml>`__,"Compute the 'heat index' as calculated by the National Weather Service","``geocat.comp.heat_index()``",`example notebook <../ncl_entries/meteorology.ipynb#heat-index-nws>`__

ncl/ncl_raw/meteorology.ncl

@@ -0,0 +1,53 @@
+; dewtemp_trh
+; Adapted from https://www.ncl.ucar.edu/Document/Functions/Built-in/dewtemp_trh.shtml
+
+; ncl -n dewtemp_trh.ncl >> dewtemp_trh_output.txt
+
+print("Temperature (K), Relative Humidity (%), Dew Temperature (C)")
+do tk=273,374
+	do rh=1,100
+		begin
+		dewtemp = dewtemp_trh(tk,rh)-273.15
+		print (tk +","+ rh +","+ dewtemp)
+		end
+	end do
+end do
+
+; daylight_fao56
+; Adapted from https://www.ncl.ucar.edu/Document/Functions/Crop/daylight_fao56.shtml
+
+; ncl -n daylight_fao56.ncl >> daylight_fao56_output.txt
+
+print("DOY, Latitude (Degrees), Daylight Hours")
+do doy=0,365
+	do lat=-66,66
+		begin
+		daylight_hours = daylight_fao56(doy, lat)
+		print (doy +","+ lat +","+ daylight_hours)
+		end
+	end do
+end do
+
+; heat_index_nws
+; https://www.ncl.ucar.edu/Document/Functions/Contributed/heat_index_nws.shtml
+
+; ncl -n heat_index_nws.ncl >> heat_index_nws_output.txt
+
+print("Temperature (F), Relative Humidity (%), Alternate Coefs (True/False), Heat Index (F)")
+do tf=0, 115
+	do rh=1,100
+		begin
+		heatindex = heat_index_nws(tf,rh,(/2,2/), False)
+		print (tf +","+ rh +"," + "0" + "," + heatindex)
+		end
+	end do
+end do
+
+do tf=0,115
+	do rh=1,100
+		begin
+		heatindex = heat_index_nws(tf,rh,(/2,2/), True)
+		print (tf +","+ rh +"," + "1" + "," + heatindex)
+		end
+	end do
+end do

ncl/receipts/heat_index_nws.ncl

@@ -0,0 +1,18 @@
+print("Temperature (F), Relative Humidity (%), Alternate Coefs (True/False), Heat Index (F)")
+do tf=0, 115
+	do rh=1,100
+		begin
+		heatindex = heat_index_nws(tf,rh,(/2,2/), False)
+		print (tf +","+ rh +"," + "0" + "," + heatindex)
+		end
+	end do
+end do
+
+do tf=0,115
+	do rh=1,100
+		begin
+		heatindex = heat_index_nws(tf,rh,(/2,2/), True)
+		print (tf +","+ rh +"," + "1" + "," + heatindex)
+		end
+	end do
+end do