#PRESSURE ALTITUDE FORMULA MANUAL#
#PRESSURE ALTITUDE FORMULA TV#
#PRESSURE ALTITUDE FORMULA DOWNLOAD#

If you don't wish to use the chart, you may do the following steps:

If you have obtained your Density Altitude from this chart, you may skip down to 'How Accurate is this Calculation' below. Read the Density Altitude in feet from the scale on the left side of the chart. Then find the position on that line which corresponds to your temperature, using the scale at the bottom of the chart. Use the Pressure Altitude obtained from Step 1.įind the blue line in the chart which corresponds to your pressure altitude, interpolating if necessary between the lines. You can use this chart to do the temperature correction. No, it's not going to be precisely accurate, as it's based upon two assumptions, one that the barometric pressure at sea level is always 29.92, and a second that atmospheric pressure declines at the rate of 1 inch of mercury per thousand feet of altitude gain - but it's better than nothing. Pressure Altitude = 29.92 - (Physical Altitude / 1000) Station Pressure = 30.14 - (4500 / 1000) = 30.14 - 4.5 = 25.64īut what if we have nothing to tell us the atmospheric pressure at all? Then do this:

#PRESSURE ALTITUDE FORMULA TV#

The sea-level barometric pressure is also what is reported by radio and TV stations.Įxample: Your local TV station is reporting that the barometric pressure is 30.14 inches. You may obtain the sea-level barometric pressure from the weather service. Station Pressure = Sea-level Barometric Pressure - (Physical Altitude / 1000) If we have no instrument to measure the local station pressure, but we know the sea-level barometric pressure, we can do this:Īn approximation for the station pressure is: If you have obtained the Pressure Altitude from the table above, you may skip to Step 2 below.

#PRESSURE ALTITUDE FORMULA DOWNLOAD#

If you would like to download a copy of the Excel spreadsheet upon which the table above is based, so you can print your own copy, right-click on the following link: Pressure Altitude Spreadsheet. Finding 19.5 in the table, I see the Pressure Altitude is 11,374 feet. If you aren't familiar with the distinction between station pressure and barometric pressure, you may wish to read this reference: Barometric Pressure and Ballistic SoftwareĮxample: The sensor in my Casio Pathfinder watch reads a pressure of 19.5 inches.

Just pick the nearest increment to your station pressure. It's in increments of 0.25 inches of mercury. If you have the station pressure from an instrument you carry, the easiest way to find the Pressure Altitude is to consult the table below. The easiest method for doing this is to print copies of the table and the chart below, and use those. Then we must compensate the pressure altitude for the temperature, which is usually different than the ICAO standard temperature at the pressure altitude. The pressure altitude is the altitude an aircraft altimeter would read at our location if the reference pressure on the altimeter were set to the current sea-level barometric pressure. However, it will get you pretty close if you don't have a Kestrel or other weather meter to do the calculation for you.įirst we must calculate the pressure altitude, because barometric pressure varies, which affects the pressure altitude. Your Kestrel includes humidity in its calculation of density altitude. This article is an addition to and continuation of the method of using density altitude in computing ballistic performance, Making Ballistic Cards Using Density Altitude

#PRESSURE ALTITUDE FORMULA MANUAL#

My question is what equation is used to calculate current location altitude given current location temperature and current location pressure (or, if no such equation exists, best suited in range from sea level to 2 km altitude).Manual Calculation of Density Altitude Manual Calculation of Density Altitude However, this formula isn't what I was looking for because it appears that the temperature at current location isn't taken into account. This formula uses more constant values including the universal gas constant, $R^*$, the gravitational acceleration, $g_0$ and the molar mass of Earth's air, $M$. This website uses the 'hypsometric formula': This project is done between altitudes of-100 meters to 2000 meters above sea level. Temperature, pressure and altitude of a 'reference-level' could be provided if necessary (using a fixed sea-level pressure constant is also acceptable). In a certain project, I need to calculate the altitude of the current location given the current location temperature and current location pressure.

Pressure altitude formula