Elevation Correction Tables for Barometers

1 NOVALYNX CORPORATIONELEVATION Correction TABLESFOR barometric pressure SENSORSNovaLynx Corporation431 Crown Point Cir Ste 120 Grass Valley, CA 95945-9531 USAP hone: (530) 823-7185 Email: 1988-2020 by NovaLynx CorporationELEVATION Correction TABLESFOR barometric pressure SENSORSINTRODUCTIONW eather stations located at elevations above sea level often need adjustment to the barometer sothat sea level pressure is the indicated value. Sometimes the information necessary making for theadjustment is unavailable or is difficult to obtain. This document provides Tables that give thebarometer corrections for various elevations. A brief discussion of the concept of pressurevariations with Elevation is also THE TABLESB arometer corrections to sea level pressure are most often associated with airports, televisionreports, or National Weather Service offices.

2 These organizations give sea level reduced pressurereadings. Some large organizations may have networks of weather stations spread over a largeregion to measure lateral variations in pressure such as those produced by weather fronts. It is notnecessary for a barometer to be corrected to sea level in order for it to operate. The correctionadjustment is simply a preference for the way that pressure is pressure corrections can be obtained by contacting a local airport or National WeatherService weather station operator and requesting the current local reading. The barometer inquestion is then adjusted so that its reading matches that obtained from the airport or NWS. Someerror will be introduced using this method of adjustment, increasing with distance since lateralpressure variations may increase with the horizontal distance from the reporting weather Tables provided with this document are based upon the United States Standard Atmosphereand can be used in situations where no reporting stations exist within the immediate area.

3 Thetables give the Correction factor that is added to the barometric pressure reading for a given stationelevation. The Correction is given both in inches of mercury (inHg) and in millibars (mb). Values areindicated for elevations expressed in feet above sea any station Elevation , add the deviation from zero figure to the barometer s currentbarometric pressure an example, consider a barometer located at an Elevation of 4550 feet with a current readingof inHg. Using the Tables , a value of inHg should be added to the reading. Thebarometer should be adjusted until it produces a reading of inHg to report the equivalent sealevel standard pressure figures indicate the calculated barometric pressure at each elevationbased upon the United States Standard Atmosphere.

4 Actual pressures typically vary by up to1 inHg (34 mb), depending upon weather conditions, time of year, and time of day. The variationis seldom more than 2 inHg (68 mb) from the values given, even in a severe storm. These figuresprovide a method for checking a barometer s operation. A barometer that is located at an elevationof 1950 feet and is reporting a pressure of 860 mb has a calibration problem or is sitting in the eyeof a super hurricane!STANDARD pressure VS. ELEVATIONFeet and mbStationStandardDeviationElevationPress urefrom zero( feet ) ( mb ) ( mb )_____ 0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 zero( feet ) ( mb ) ( mb )

5 _____ 1950 3650 pressure VS. ELEVATIONFeet and mbStationStandardDeviationElevationPress urefrom zero( feet ) ( mb ) ( mb )_____ 3900 zero( feet ) ( mb ) ( mb )_____ 5850 pressure VS.

6 ELEVATIONFeet and inHgStationStandardDeviationElevationPre ssurefrom zero( feet ) ( inHg ) ( inHg )_____ 0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 zero( feet ) ( inHg ) ( inHg )_____ 1950 pressure VS.

7 ELEVATIONFeet and inHgStationStandardDeviationElevationPre ssurefrom zero( feet ) ( inHg ) ( inHg )_____ 3900 zero( feet ) ( inHg ) ( inHg )_____ 5850