Furthermore, water vapor is lighter than air and, so, more humid air is less dense than less humid air (though not by much). Your actual elevation could easily be as low as about 5000 feet when the density altitude is 8000 feet.įor simplicity's sake, humidity is often ignored in calculating density altitude, as it's impact on air density is relatively small. If you calculate an density altitude of 8000 feet, that means the air density at your location is the same as the "standard" density at an elevation of 8000. Air density will affect the speed, performance, and climbing rate of the aircraft.Īltitude density is a way of expressing what your actual air density is in terms of the "standard" density at a given altitude. Since airplanes fly through the medium of air, it's important to know how dense the air is on any given day and for any given flight. If you are a pilot, you are already familiar with the notion of density altitude. To illustrate how misguided this assumption is, we need to introduce the ideas of density altitude and adjusted barometric pressure. What the NCAA conversion tables fail to take into account, however, are the other factors that influence air pressure and density-things like temperature, humidity, and movement of weather systems. In effect, the NCAA converstions proceed under the assumption that the abundance of oxygen molecules remains constant at each of the various competition venues located at elevations in excess of 3000 feet. And, since altitude is so easy to quantify, the NCAA eventually created a table of conversions for adjusting distance performances at each of the member schools' tracks located above 3000 feet elevation.Ī sampling of those adjustments would include:Ī 9:30.00 3K run at the Great Friends of the University of New Mexico track is converted to a 9:15.21 equivalent at sea level.Ī 4:30.00 1500 run at Rex Field on the campus of Adams State College is converted to a 4:18.62 equivalent at sea level.Ī 30:00.00 10K at New Mexico State track in Las Cruces is converted to a 29:21.77 equivalent at sea level. It is merely the most obvious and the easiest to quantify of the factors that affect air pressure and density. Therefore, the packing of oxygen molecules is more dense at sea level than it is in Albuquerque, meaning that oxygen is more abundant at sea level than in Albuquerque.īut altitude is far from the only thing that affects air pressure and density. At sea level, the air you breathe is compressed by 5000 more vertical feet of atmosphere than the air you breathe in Albuquerque. The towels at the bottom of the stack bear more weight and thus become more compressed than the towels higher in the stack. The weight of the stack compresses the towels in the stack. Once the towels are stacked, compression starts to take place. You can think of the atmosphere as something like the stack of bath towels in your closet. ![]() ![]() In fact, from a human performance standpoint, altitude is little more than differentiated density of oxygen molecules. The air is lense dense at higher elevation and, so, the oxygen molecules needed to make the human machine run are in shorter quantity. I'll monitor that frequently and do my best to quickly answer any questions that arise.įor years, we've accepted the notion that running distance is more difficult at higher elevation than lower. Whether you accessed from the Utah or New Mexico site, please know that you're welcome to add your questions to the comments section of this article. To all readers from Utah, although this article relies on examples from New Mexico, you should easily be able to draw parallels to Utah. There is some information included in this article that was not included in the clinic presentation, but the vast majority of the content was included in the clinic session. Note: This article is a written summary of a clinic presentation I gave Tuesday, July 31, at the New Mexico High School Coaches Association Clinic in Albuquerque. When you live in the shadow of the Rocky Mountains, it's easy to assume that altitude is all you need to know to assess distance performance.
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