Density Altitude

[Konstantinos]

What exactly is the density altitude? I have not understood it.

We say for altitude or elevation: I am 2.000 m ABOVE MEAN SEA LEVEL.

What we say for denisty altitude? I am 2.000 m ABOVE WHAT?

If I am in a mountain peak which is 2.000 m above sea level, then can my density altitude be 1.500 m? 2.000 m? 2.500 m?

Is there a formula - function which gives me the density altitude? It depends on altitude, temperature and humidity? What humidity? Absolute or relative?

Thank you.

[flyer]

You could look at Wikipedia which tends to be very scientifically orientated but this link is much simpler

http://www.flyingmag...altitude-pencil

[Konstantinos]

Hello again flyer. I studied your link and wikipedia, and I think I understood. So, I created a script on matlab, using wikipedia's formula: http://en.wikipedia.org/wiki/Density_altitude#Calculation

Code:

fprintf ( 1,'Hello, I will calculate your density altitude.\n' );ts=input('Please, give me the sea level temperature (degrees C):');fprintf ( 1, 'Thank you.\n' );ps=input('Please, give me the sea level atmospheric pressure (mb):');fprintf ( 1, 'Thank you.\n' );tm=input('Please, give me the temperature of your position (degrees C):');fprintf ( 1, 'Thank you.\n' )pm=input('Please, give me the atmospheric pressure of your position (mb):');fprintf ( 1, 'Thank you.\n' );da=145442.156*(1-((pm/ps)/((tm+273.15)/(ts+273.15)))^0.234969);dam= da/3.2808399;fprintf('Your density altitude is %d m or %d feet\n', dam, da);

And a simple running:

>> Density_AltitudeHello, I will calculate your density altitude.Please, give me the sea level temperature (degrees C):17Thank you.Please, give me the sea level atmospheric pressure (mb):1017.9Thank you.Please, give me the temperature of your position (degrees C):23.5Thank you.Please, give me the atmospheric pressure of your position (mb):999.9Thank you.Your density altitude is 4.146678e+002 m or 1.360459e+003 feet>> 

Is it good? What is your opinion?

I am trying to understand the difference between "altitude" and "density altitude". I can see only one difference. The altitude does not depend on my position's current air temperature, but the density altitude does. If my position's current air temperature is increased, then the density altitude is also increased, but the altitude remains fixed. If my position's current air temperature is decreased, then the density altitude is also decreased, but the altitude remains fixed.

I am wondering if I am right.

Also my multimeter says: The DENSITY ALTITUDE screen is calculated from the absolute values of station pressure, relative
humidity and temperature. So, what formula it uses?