Vad är skillnaden mellan de olika automatiserade väderobservationssystemen?

ASOS är i grund och botten en ersättning för AWOS med fler rapporteringsparametrar, och de första enheterna installerades 1991. Enligt Automatiserat flygväder station Wikipedia-sida har varje olika typ följande parametrar:

AWOS

• AWOS A: barometric pressure and altimeter setting (in inches of Mercury).
• AWOS I: wind speed and wind gusts (in knots), wind direction (from which the wind is blowing) and variable wind direction (in degrees of the compass), temperature and dew point (in degrees Celsius), altimeter setting and density altitude.
• AWOS II: all AWOS I parameters, plus visibility and variable visibility (in miles).
• AWOS III: all AWOS II parameters, plus sky condition (in oktas), cloud ceiling height (in feet), and liquid precipitation
  accumulation (in inches).
• AWOS III P: all AWOS III parameters, plus precipitation type (rain, snow and sometimes drizzle) identification.
• AWOS III T: all AWOS III parameters, plus thunderstorm detection (via a cloud-to-ground lightning detector).
• AWOS III P/T: all AWOS III parameters, plus precipitation type identification and thunderstorm detection.
• AWOS IV Z: all AWOS III P/T parameters, plus freezing rain detection via a freezing rain sensor (Note: this configuration used
  to be called AWOS III PTZ).
• AWOS IV R: all AWOS III P/T parameters, plus runway surface condition.
• AWOS IV Z/R: all AWOS III P/T parameters, plus freezing rain detection and runway surface condition.

ASOS

They generally report all the parameters of the AWOS-III, while also having the additional capabilities of reporting temperature and dew point in degrees Fahrenheit, present weather, icing, lightning, sea level pressure and precipitation accumulation.