[Physics] Pressure at ground level and at sea level

homework-and-exercisesmetrologypressuresi-unitsunits

$1$atm $= 101325$pa
$1$bar $= 100000$ pa
$1$atm $= 1.013$ bar
$1$bar $= 0.987$atm

From wiki:

The bar is a metric (but not SI) unit of pressure exactly equal to $100000$ Pa.[1] It is about equal to the atmospheric pressure on Earth at sea level.
Atmospheric pressure is the pressure exerted by the weight of air in the atmosphere.

My question: I presume ground level is higher than sea level. #Why is the pressure at sea level Less than at ground level?#
I thought that since sea level is at a lower level, there will be a greater weight of air and hence higher pressure on it compared to at ground level

my correction. I am sorry. Why is the pressure at sea level =1bar Less than at ground level=1atm, when supposedly there would be more air hence a greater weight of air hence a higher pressure?

Best Answer

As David has mentioned, you are interpreting too much into the value 101'325 Pa. This is an average pressure which can change quite a lot depending on the weather. E.g. if you are in a low pressure system, the sea level pressure can be far bellow 100'000 Pa, If the local weather is a high pressure system, it will be much higher than 101'325 Pa.

Of course you are right: ground level pressure is usually lower than sea level pressure.