On average, approximately how many days per year is the temperature at the North Pole colder than at the South Pole; 200, 160, 120, 80, 40? How many days per year is the North Pole temperature colder than Vostok, Station, Antarctica?
You would expect temperatures along the Equator to be hot, and they are except in locations where high mountains protrude. However, even though the Congo Basin in Africa and the Amazon Basin in South America , which straddle the Equator, can be insufferably hot all year long, they're not necessarily the hottest places on Earth. Desert locales, such as the Arabian Desert or Great Sandy Desert of Australia , and inland areas below sea level, such as the Dead Sea Valley or Death Valley , typically register higher temperatures than locations smack on the Equator. Cloud free areas with little vegetation, even if 25 º or more from the Equator, are apt to be considerably hotter during the summer season than is a steamy jungle. In parts of the Sahara Desert , the average insolation or solar energy (short-wave and long-wave) received during the course of a year is over 200 kilolangleys, whereas in Zaire , the average annual value is closer to 120 kilolangleys.
The same can be said about the North and South Pole. Although they're brutally cold, they're not necessarily the coldest places on our planet. The lowest temperatures occur where the surface is snow covered, solar radiation is minimal, the air is extremely dry, and drainage allows the more dense colder air to accumulate. So for instance, the village of Verkhoyansk in northeastern Siberia, situated along a stream bottom and confined by mountains, is often much colder than the North Pole, positioned in the ice covered Arctic Ocean . The lowest temperature ever observed in the Northern Hemisphere was recorded at Verkhoyansk (-94º F or - 67.8º C). While not exactly the north geographic pole, northeastern Siberia is one of the two cold poles in the Northern Hemisphere; the other is the Greenland Ice Sheet. Both of these areas are bitterly cold during the winter months. Intense surface cooling with subsidence and the formation of a persistent low-level inversion insure that cold air remains in place. You definitely don't want your tongue coming in contact with metal here.
Similarly, Vostok Station in Antarctica is colder than the South Pole. Vostok, though, is higher than the Pole. Both the South Pole and Vostok lie atop a huge ice cap. The South Pole has an elevation of over 9,000 ft (2,743 m), and Vostok Station is nearly almost 11,500 ft (close to 3,500 m) -- the higher altitude essentially accounts for the lower temperature readings. If both stations are governed by the same air mass, and with a lapse rate of 5.5 º F per thousand ft. (1 º C per 100 m) in dry (unsaturated) air, temperatures at Vostok can be expected to be nearly 15º F colder than at the Pole. Vostok is unquestionably the coldest spot on Earth. Its average annual temperature is -67 1º F (-55.1º C)! Very few humans have been subjected to such harsh temperatures. More astounding are the minimum temperatures at Vostok, the lowest temperatures ever recorded on our planet. In July of 1983 a confirmed temperature of -128.6º F (- 89.2º C) was observed, and in the winter of 1997, and unconfirmed temperature of -132º F (- 91º C) was reported. By the way, the temperature at Vostok has never been above 0º F (-18º C), and its much colder there than at the summit of Mt. Everest . Best to just keep your tongue inside your mouth if you happen to visit Vostok.
Ok, so now we know that the Poles aren't necessarily the coldest points on the Earth's surface, but since they're, well, poles apart, how do their temperature regimes compare? In a nutshell, the South Pole is colder, a lot colder. Basically, it's colder not only because it's more than 9,000 feet (2,743 m) higher but also because it has a higher continentality than it's northern counterpart. Continentality is the measure to which a spot on the Earth's surface if influenced by a landmass. It's partially based on the distance to the sea or other large moisture source. Theoretically, the coldest minimum temperature should occur where the continentalty is highest. The area around the North Pole consists of ice flows, which are commonly about 10 ft (3m) thick, beneath which lies relatively warm seawater (~28 F or �2C). Since the South Pole is near the center of Antarctica, a landmass 1.7 times larger than Australia, and since the North Pole is in an ocean, albeit a frozen one, it's pretty obvious which one has a higher continentality.
At the poles, there are actually only 2 days in the year; each lasts 6 months. For more than 180 consecutive days the Sun circles the sky and is constantly above the horizon, though not far above it. When it finally tires and sets, it does so for more than 180 successive days, cloaking the pole in abysmal darkness, resulting in some of the most inhospitable conditions on Earth. If you're not familiar with Seasonal Affective Disorder (SAD), you will be if you over-winter at the South Pole.
At the South Pole (Amundsen-Scott Station), the average temperature of the coldest month (August) is approximately �76 F (� 60 C), and the average temperature of the warmest month (January) is � 18º F (�28.2 C). Records go back at the South Pole to 1957. At the North Pole, long term temperature records aren't available, but in 2003 a live weather camera and an unmanned weather station were installed on the sea ice. During the last 3 years, the daily temperatures have vacillated between about �40º F (-40º C) during December and January to a little above freezing (0º C) in June, July and August. The seawater below the ice provides enough heat to keep winter temperatures from falling much below about �40º F (-40º C). I suppose all the activity of Santa and his mischievous little helpers, plus 8 or 9 tiny reindeer might be responsible for boosting the temperatures here a little too.
At the South Pole, temperatures in January average about �18º F (-28º C), while at the North Pole, the January temperatures range from between about �15º F (-26 C) to about �45º F (-43 C) and perhaps average about �30º F (-34 C). Therefore, the average temperature during the warmest month at the South Pole is only about 12 degrees warmer (F) than the coldest month at the North Pole. January is the only month when the North Pole temperatures are colder than those at the South Pole. So, on a day-to-day basis it's likely that less than 40 days in a given year are colder at the North Pole than the South Pole. At Vostok, the average January temperature is �25.7º F (-32.1º C), just a few degrees warmer than the North Pole, and thus in a given year maybe less than 2-dozen days are colder at the North Pole than at Vostok Station.
For more about this, see the following links.
http://www.arctic.noaa.gov/np2003/gallery_np_weatherdata.html#weather
North Pole Weather Data
http://hypertextbook.com/facts/2000/YongLiLiang.shtml
Coldest Temperatures on Earth
http://www.gi.alaska.edu/ScienceForum/ASF6/682.html
Alaska Science Forum
This week's question is provided by Dr. James Foster. Dr. Foster originated this series and did it as a solo project for the GSFC website for SEVEN YEARS! Two years ago, Dr. Foster has decided to share the enthusiasm he has for this project with other Goddard scientists and will be posing questions on a semi-regular basis.