GGR214H5 Lecture Notes - Lecture 8: Zinal, Fluid Parcel, Polar Easterlies
Document Summary
Wind is the horizontal movement of air: results from the action of forces, ca(cid:374) (cid:271)e e(cid:454)plai(cid:374)ed usi(cid:374)g ne(cid:449)to(cid:374)(cid:859)s la(cid:449) Forces that act on the air: gravity, pressure gradient, coriolis force, centripetal force, friction. Thes forces explain the relationship bw winds we observe and the patterns of isobars or height contours on weather maps. Upper air winds flow parallel to the height contours on upper air maps. Surface winds flow at an angle across the isobars on surface weather maps. Map: winds parallel to the countours, wind directions spiralling into a low or out of a high. Pressure gradient force: change in pressure over a distance, this causes a pressure gradient force pulling in the opposite direction, this is what makes the air move. If no pgf, no other forces: key to get the air moving. In between, the coriolis force is between zero and maximum: elates the st(cid:396)e(cid:374)gth of the fo(cid:396)(cid:272)e to the ea(cid:396)th(cid:859)s (cid:396)otatio(cid:374) a(cid:374)d latitude.
