ATOC 181 Lecture 4: ATOC181lec4

• School: McGill University
• Department: Atmospheric & Oceanic Sciences
• Course: ATOC 181
• Professor: Gerard Szejwach

Document Summary

Standard sea level pressure: 1013. 25 hpa ("hecto-pascal", 1013. 25 mbar (millibar, non-si unit, 1 atm ("atmosphere"; an older unit) Pressure and density profiles: both air pressure and density decrease exponentially with height. Vertical pressure and atmospheric mass: at 5500m above sea level, one is above 50% f an air column"s total mass, aircraft cabins are pressurized, to supply enough oxygen to passengers at 11km altitude. Why don"t we feel air pressure: because it acts in all directions, body"s internal pressure adjusts to atmosphere, so there is no pressure difference, also: lungs are never fully emptied when exhaling. Radiosondes for vertical profiles: used for vertical air profiling up to 30 km altitude (until the balloon bursts, developed in the 1920s, measures temp, pressure, humidity and sometimes position (gps racking, released twice daily from many locations worldwide. Small instrument package carried by helium balloon equipped with a radio transmitter. "cold" far above earth (outer space: **different from what we believe (complex, not simple)**