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Monday, August 15, 2011

Are there any differences in the atmosphere like temperature, wind speed etc. between Arctic and Antarctic regions?

The two regions, the Arctic and the Antarctica, are located around the north and the south poles of the earth, respectively. The atmosphere at both these places is very cold and they experience extreme solar exposure periods. Therefore, there are several similarities in the weather patterns. However, there are quite a few differences too.

The rotation at the (Antarctic) south pole is opposite to that at (Arctic) north pole. This is manifest in the nature of wind circulation and in the water whirlpools. Also, being in the two opposite hemispheres, there exists a complementarity in the seasonal changes.

The winter period at the Arctic happens to be the summer in the Antarctica and vice versa. On top of that, there is seasonal variation in the climatic conditions in both the regions.

The other main difference arises from the fact that the Arctic is an ocean with frozen ice cover. It is surrounded and partly contributed by the edges of land masses, while the Antarctica is an ice covered land mass (continent) surrounded by oceans. This leads to differences in the temperature patterns in the two regions.

The temperature in Arctic zone drops below -50 degree Celsius in the winter and summer temperature ranges between +10 and -10 degree C. Much of arctic zone is surrounded by relatively warmer ocean water with minimum temperature above -2 degree Celsius. In the Antarctica the interior regions do not benefit from the moderating influence of the ocean waters.

In fact, during the winter, the snow and ice covered Antarctica nearly doubles in size, rendering any influence of the surrounding ocean unreachable into the interiors of the continent. And the temperature is normally much lower compared to the Arctic region.

The lowest temperature can be as low as -90 degree C in the winter and the summer time sees an average temperature in the range of -5 to -35 degrees. Also due to such low temperatures, the atmosphere is very dry. Also in the Antarctica, the wind is very strong with the speed as high as 325km/h while in the arctic the wind is mild with speed in the range of about 20km/h.

In the Antarctic, about 98 per cent of the area is covered with snow and ice all throughout the year. Thus, the sunlight is almost totally gets reflected back rather than getting absorbed. Further, the atmosphere being so dry as to have the average humidity in the range of only 0.03 per cent, is devoid of water vapour and so the sunlight escapes completely instead of getting absorbed by the atmosphere too.

This also contributes to the low temperature in the region. Blizzards are a typical Antarctic phenomenon in which very little, if any, snow actually falls. Instead the loose top layer of the snow is picked up and blown along the surface by the wind. Such phenomena are not experienced in the Arctic zone.

PROF. H. K. SAHU
Chennai Mathematical Institute, Chennai

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