Answer to Question 1
ANSWER: Buys Ballots law, after the Dutch meteorologist Christophorus Buys Ballot (18171890), who formulated it, describes the relationship between wind and pressure. We know that, because of friction, surface winds move more slowly than do the winds aloft with the same pressure gradient. Surface winds also blow across the isobars toward lower pressure. The angle at which the winds cross the isobars depends upon surface friction, wind speed, and the height above the surface. Aloft, however, the winds blow parallel to contour lines, with lower pressure (in the Northern Hemisphere) to their left. Consequently, because of this fact, if you (in the Northern Hemisphere) stand with the wind aloft to your back, lower pressure will be to your left and higher pressure to your right. The same rule applies to the surface wind, but with a slight modification due to the fact that here the wind crosses the isobars. At the surface, if you stand with your back to the wind, then turn clockwise about 30 degrees, the center of lowest pressure will be to your left.
Answer to Question 2
ANSWER: The combination of the pressure gradient force and Coriolis force cause winds to flow in a west to east pattern. The decrease in contour line height from south to north is the result of air at this level being warmer in the south and colder in the north. On maps, where horizontal temperature contrasts are large there is also a large height gradientthe contour lines are close together and the winds are strong. Where the horizontal temperature contrasts are small, there is a small height gradientthe contour lines are spaced farther apart and the winds are weaker. In general, on maps such as this we find stronger north-to-south temperature contrasts in winter than in summer, which is why the winds aloft are usually stronger in winter.
