ATOC 181 Lecture Notes - Lecture 10: Countercurrent Exchange, Advection, Tropopause
10 Mar 2016
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A: represents a time-averaged (smoothed) picture of global wind systems - average air flow, prevailing winds: local winds and weather can vary greatly from this average. If the earth was not rotating (or very slowly) and uniformly covered by water, we would have a simple thermally direct circulation (at least on sun-facing side). With earth"s rotation, single-cell breaks down into 3 cells (per hemisphere) on a uniformly water-covered planet earth. Real-world general circulation is much more complicated due to land/ocean contrasts, topography (mountain ranges), seasonality, etc: semi-permanent highs and lows (h"s often found in subtropical latitudes, as suggested by 3-cell model, but not constantly), (the following figure) seasonality. Left: entire patterns shift south in nh winter. Shows average sea-level pressure distribution and surface wind-flow patterns for jan. Right: entire patterns shift north in nh summer. Shows average sea-level pressure distribution and surface wind-flow patterns for july. - a snapshot of typical nh winter flow.
