The Coriolis effect and wind direction.

Why don't winds move directly north to south? The prevailing winds do not move in a straight north–south direction because of the Coriolis effect. In the Northern Hemisphere, the Coriolis effect causes an apparent deflection of winds to the right of their direction of travel and to the left in the Southern Hemisphere. We say “apparent” deflection because we see this deflection only if we make our observations from the surface of the earth. To an observer in space, it would appear that winds move in approximately a straight line, while the earth rotates beneath them.  Geographic variation in temperature and precipitation is very complex, but also very important to the science of ecology. The distributions of biomes we discuss in this chapter is substantially influenced by geographic variation in temperature and precipitation. How can we study and represent variation in these climatic variables without being overwhelmed by a mass of numbers? This practical problem is addressed by a visual device called a climate diagram.