Why is the air more dense at sea level than at a mountain top?

Answer 1

In simple terms - gravity ! The closer you are to the Earth's core - the higher the gravity. At mountain summits - the gravity is less - therefore the air molecules are able to move further apart.

Answer 2

Mean sea level pressure (MSLP) is the pressure at sea level or (when measured at a given elevation on land) the station pressure reduced to sea level assuming an isothermal layer at the station temperature.

This is the pressure normally given in weather reports on radio, television, and newspapers or on the internet. When barometers in the home are set to match the local weather reports, they measure pressure reduced to sea level, not the actual local atmospheric pressure. See Altimeter (barometer vs. absolute).

The reduction to sea level means that the normal range of fluctuations in pressure is the same for everyone. The pressures which are considered high pressure or low pressure do not depend on geographical location. This makes isobar Isobar

Isobar may refer to:* A contour line of equal or constant pressure in meteorology* Isobar , in nuclear physics, one of multiple nuclides with equal numbers of nucleons* A heat pipe* Isobar , a 2009 science fiction film...

s on a weather map meaningful and useful tools.

The altimeter Altimeter

An altimeter is an instrument used to measure the altitude of an object above a fixed level. The measurement of altitude is called altimetry, which is related to the term bathymetry, the measurement of depth underwater.-Pressure altimeter:...

setting in aviation, set either QNHQNH

QNH is a Q code. Most commonly referred to as "Quasi-Non-Hydrostatic". It is a pressure setting used by pilots, air traffic control and low frequency weather beacons to refer to the barometric altimeter setting which will cause the altimeter to read altitude above mean sea level within a certain...

or QFE, is another atmospheric pressure reduced to sea level, but the method of making this reduction differs slightly.

QNH: The barometric altimeter setting which will cause the altimeter to read airfield elevation when on the airfield. In ISA temperature conditions the altimeter will read altitude above mean sea level in the vicinity of the airfield

QFE: The barometric altimeter setting which will cause an altimeter to read zero when at the reference datum of a particular airfield (generally a runway threshold). In ISA temperature conditions the altimeter will read height above the datum in the vicinity of the airfield.

Answer 3

The answer is very simple, it all depends upon its depth, the more you go down less propotion of o2(oxygen) decreases because less creatures live in their!.