Add windchill calculation to Vantage agent (#550)

* Added wind chill temperature to acquisition data

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Limit wind chill calc upper range

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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Brian Koopman <[email protected]>

socs/agents/vantagepro2/drivers.py

@@ -2,6 +2,7 @@
 import struct
 import time
 
+import numpy as np
 from serial import Serial
 
 # some commands require a CRC code (cyclic redundancy check) -
@@ -58,6 +59,22 @@ def F_to_C(temp):
     return (temp - 32) * (5 / 9)
 
 
+def wind_chill(temp, wind):
+    """Function to calculate wind chill temperature. Only valid if temp < 50F.
+    Taken from https://www.calculator.net/wind-chill-calculator.html
+    If temp > 50F, need to use heat index instead...
+
+        Temp: Temperature in Fahrenheit
+        wind: Speed in miles per hour
+    """
+    # Calculation not valid above 50 F
+    if temp > 50:
+        return temp
+
+    chill = 35.75 + 0.6215 * temp - 35.75 * np.power(wind, 0.16) + 0.4275 * temp * np.power(wind, 0.16)
+    return chill
+
+
 class VantagePro2:
     """Allows communication to Vantage Pro 2 Weather Monitor Module.
     Contains commands to be issued and member variables that store
@@ -318,6 +335,11 @@ def receive_data(self):
         loop_data['time_sunrise'] = byte_data[75]
         loop_data['time_sunset'] = byte_data[76]
 
+        # Add wind chill temperature to observation data
+        temp = byte_data[9] / 10.0
+        wind_speed = byte_data[10]
+        loop_data['wind_chill_temp'] = F_to_C(wind_chill(temp, wind_speed))
+
         # Correct UV Index by a factor of 10 and fix overflow
         uvi = loop_data['UV']
         if uvi < 0: