Clarification of Answer by
17 Jun 2004 10:33 PDT
Hello again abook.
The answer is not really the complex atmospheric patterns, it is the
fact that the southern hemisphere has more area of ocean than the
northern hemisphere, thus when the Earth is closer to the sun the
southern oceans absorb that extra energy more than the in the northern
hemisphere where there is more land area.
"There is more land in the Northern Hemisphere, and more water bodies
in the Southern Hemisphere. Now, land has a much lower specific heat
capacity than water; in other words, water can hold a lot of heat
while land cannot. Hence, land gets heated up faster and also cools
faster than water. So, during summer, the greater amount of land in
the northern hemisphere gets heated up quicker, while in the southern
hemisphere, the water soaks a lot of heat and gets warmer by a much
lesser amount. In any case, the result is that northern summers are
hotter than the southern summers"
"Even though the difference between the earth?s perihelion and
aphelion distances is less than 3%. The amount of solar energy
striking the earth is 7% greater at perihelion (in January) than at
aphelion (in July). This would lead one to conclude that summer in the
southern hemisphere, which occurs at perihelion, is warmer than summer
in the northern hemisphere. This, however, is not the case. Most of
the land mass of the earth is concentrated in the northern hemisphere.
The southern hemisphere, by contrast, is 80% covered by water. Water
has the ability to absorb large amounts of heat. The additional solar
energy supplied by the sun at perihelion is absorbed by the large
bodies of water in the southern hemisphere. The result is that
temperatures are actually more moderate during summers in the southern
hemisphere. On Mars, which does not have any oceans to absorb heat,
the temperature fluctuations are much greater due to perihelion and
"But that's not the whole story. Earth is warmer overall in July due
to the unequal distribution of land on the planet. Oceans and
continents are not distributed evenly around the globe, so the summer
sun beating down on the extensive land in the Northern Hemisphere
raises the temperature more than it does in the Southern Hemisphere
six months later."
Very best regards