The force on a square centimeter area of an air column, which runs from sea level to the edge of the atmosphere, is about 10.13 N.
Therefore the absolute atmospheric pressure at sea level is approx. 10.13 x 104 N per square meter, which is also called 1 Pa (Pascal), the SI unit for pressure.
A basic dimension analysis shows that 1 bar = 1 x 105 Pa. The higher above sea level you are the lower the atmospheric pressure and visa versa.