How Does Altitude Affect Humidity Sensor Readings?

AI Thread Summary
Altitude affects humidity sensor readings due to changes in atmospheric pressure and temperature, which influence both relative and absolute humidity calculations. To convert relative humidity to absolute humidity, the vapor pressure must be accurately determined, as it varies primarily with temperature. The atmospheric pressure also changes with altitude, and while it can be approximated using an exponential model, direct measurements provide greater accuracy. Understanding the relationship between vapor pressure and temperature is crucial for accurate humidity readings at different altitudes. Accurate calculations require considering both the atmospheric pressure and vapor pressure profiles.
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Homework Statement


So I sent a humidity sensor up in a weather balloon, which gave a reading for relative humidity. I eventually want an absolute humidity, but I am unsure whether I need to correct the output based on the changing density and atmospheric pressure with altitude.

Homework Equations


As I understand it:
RH = (% volume of water) * atmospheric pressure / vapor pressure.
AH = mass of water / volume of air.

The Attempt at a Solution


I want to obtain the %volume of water, and multiply by the density profile of air to obtain the absolute humidity profile.

The vapor pressure changes with height (I think) since the temperature and density changes, moving you to a different spot on the vapor dome. The atmospheric pressure also changes. So is atmospheric pressure / vapor pressure a constant? If not, how can I account for that to get the % volume of water?

Thanks!
 
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Do you know how to get the atmospheric pressure as a function of altitude?
 
Yes, I can just assume the exponential atmosphere. It's the vapor pressure I'm confused about-- doesn't it change with temperature and density as well?
 
oobgular said:
Yes, I can just assume the exponential atmosphere. It's the vapor pressure I'm confused about-- doesn't it change with temperature and density as well?
It changes with temperature only.
 
You can get a more accurate pressure profile by measuring it directly, or by knowing the temperature profile and applying the barotropic equation.
 
I don't get how to argue it. i can prove: evolution is the ability to adapt, whether it's progression or regression from some point of view, so if evolution is not constant then animal generations couldn`t stay alive for a big amount of time because when climate is changing this generations die. but they dont. so evolution is constant. but its not an argument, right? how to fing arguments when i only prove it.. analytically, i guess it called that (this is indirectly related to biology, im...
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