In winter, location in the northem hemisphere may have a negative net gain ofsolar energy a and heat loss, resulting in cooler weather. The opposite is true for the summer time ofJune. seasons thus arise from the relative geometrical positions ofearth and the sun. The equatorial repon receives higher radiation from the sun at all times ofa year so there is a positive net energy gain and the region is warmer than the northem and the southern regions. This gives rise to a permanent global wind movement as illustrated in Figure 3.2.3.