# Which is the most accurate way to model the fundamental atmospheric parameters of the Earth?

I need to calculate the fundamental atmospheric parameters, I mean the actual ones, this is not an exercise but a model for a real world application so I need to take account of the humidity of air. I need to calculate the density of the air, and I've solved this by implementing this calculator in MATLAB. But now I need to find a way to calculate the input parameters which are:

• Air Temperature
• Altimeter Settings (Which is the barometric pressure right?)
• Relative Humidity

given a certain altitude in meters above the sea level. If it's not possible to calculate all the three parameters, given an altitude, please show me a way to calculate the possible ones. For example I know that for the barometric pressure the best equation is the Laplace equation which is an improved version of the barometric formula right?

• Aren't those "parameters" time-varying and/or spatially-dependent? – Kyle Kanos Aug 6 '14 at 13:15
• What data do you have? All these things change with time: the weather changes. If you want accuracy, you need current observations. – Ross Millikan Aug 6 '14 at 13:21
• @KyleKanos yes that's the same I thought but account these dependencies we would need to implement a large scale numerical simulation. Every equation and every calculator I've found it's always time and position independent. So maybe I've just explained myself in a bad way. I want the best model for the atmosphere that does not require a supercomputer or other particular data. However I found this model exploration.grc.nasa.gov/education/rocket/atmosmet.html I don't know if it takes in account humidity but I need these data for an aircraft so I think that I can trust NASA in this! – Aurelius Aug 7 '14 at 11:19