ESS124
Prof. Jin-Yi Yu
Thickness of
the Atmosphere
•The thickness of the atmosphere is only about 2% of Earth’s thickness (Earth’s radius = ~6400km).
•Most of the atmospheric mass is confined in the lowest 100 km above the sea level.
q Because of the shallowness of the atmosphere,
its motions over large areas are primarily horizontal.
čTypically, horizontal wind
speeds are a thousands time greater than vertical wind speeds.
(But the
small vertical displacements of air have an important impact on the state of the atmosphere.)
90%
70%
(from Meteorology Today)