ATOC 184 Lecture Notes - Lecture 7: Coriolis Force, Centrifugal Force, Pressure-Gradient Force
4 Feb 2019
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Document Summary
Geostrophic balance is a good approximate above 900 hpa (1. 5 km) above the ground where friction is not important. At ground levels, friction reduces wind speed which reduce coriolis force. Pgf and coriolis force are no longer equal and opposite. Wind will then flow slightly to an angle across isobar towards low pressure. Spirals in towards low pressure systems and out away from high pressure systems. Surface pressure is not dependent on temperature. Weight of the molecules above an area will be the same anywhere. How do we change the number of molecules in a column. Higher pressure = net gain of air molecules. Net inflow of air molecules into a region of atmosphere. Winds on one side of column will be faster than the other side. Air molecules are entering in column faster than air molecules are leaving. Lower pressure = net loss of air molecules. Net outflow of air molecules from a region of the atmosphere.
