A tad on the chilly side

The most prominent feature of living down here is the phenomenally cold conditions. As the second coldest continuously inhabited place on the planet, as soon as you get off the plane in the midst of summer, the cold is so much more noticeable than on the coast. As the sun disappeared, we watched the temperature gauge fall as the little warmth that the sun provided wasted away.

The temperature here is significantly dependent on the direction of the wind, with the extremes of the temperatures experienced dependent on the unique geography of the continent.

The temperatures are a result of three main factors.

Firstly, the main reason for both polar regions being colder than the tropics is that as the earth is roughly spherical, the sun’s rays are hitting the equator at a perpendicular angle so a square metre of the sun’s rays cross section are falling on a square metre of earth. However at the polar regions, that same square metre of rays are instead being cast at an angle across a much larger area. With the inclination of the planet sitting at 23.5 degrees from the ecliptic – the plane the earth and other planets orbit the sun in – the highest the sun gets in the sky is 23.5 degrees on the summer solstice, when the earth is in its orbit in such a way that pole is pointing the towards the sun. Therefore the energy of the sun is spread out over a much larger area.

As the earth rotates around the sun, the elliptical orbit of the earth is such that each pole alternates at facing the sun on opposite sides of the ellipse, and subsequently once it reaches the point where neither pole is closer to the sun (the equinox), six months of winter begins. This period of lacking sunlight means that any warmth to the region is typically transferred from other parts of the world that are sunlit, either through circulating ocean currents or wind.

Oceans typically moderate temperatures a great deal, as they are heat sinks in the warm months and heat sources as the ground loses heat in the winter. It is for this reason that shore breezes change over the course of the day at beaches – when the sun is up the land heats quicker than the sea generating warmer air with lower pressure compared to the air above the sea, and an onshore breeze results. As the sun sets, the land cools faster and the sea becomes relatively warmer, resulting on an offshore breeze.
Similarly, the ocean never gets as cold as the land as if it gets around freezing, ice will start to form, which insulates further heat loss. Furthermore, convection currents can mix cooler polar water with warmer tropical water. Therefore, the coast of Antarctica is a lot warmer than the interior. The further from the coast, the less this moderation is in effect, with the Antarctic plateau being a vast stretch close to 3000km in diameter. This same principle is what results in the interior of continents such as North America, Europe and Asia having much colder winter temperatures than islands at comparable latitudes such as New Zealand.

To add to this, as you ascend in altitude, the temperature typically drops at a steady rate, until you reach the tropopause, when temperatures rise again as you increase in height. The reason for this is, is that as air rises, the air pressure reduces and air becomes less dense. Its temperature is proportional to its pressure, so the work of expanding into a larger space causes a reduction in temperature. In addition to this, air near the surface of the ground is warmed by earth’s radiation, from heat absorbed from the sun’s rays. The further from the earth, the less effect this has. Convection within the troposphere normally causes mixing of this air.
The Antarctic plateau rises up from its surrounding coastline, and with it, falls the temperature even further.

So typically on most parts of earth, you get cooling as soon as you ascend in altitude from ground level. In winter here, we often see a strong inversion layer in the immediate vicinity of ground level. This is because two of the things that cause warming of air closest to the ground don’t occur. Firstly, there is no sunlight to warm the ground. Anywhere on the planet, if you dig down a couple of metres, you will reach a stable temperature that reflects the average temperature in that region. This is the principle behind using ground-source heat pumps in places with warm summers and cold winters. For here, that temperature 2m down is around -50C, and kept cool by a 3km thick iceslab. However, the surface of the ice (like any ground) is constantly radiating heat away, and if there are no clouds around, it is not reflected back and therefore dissipated in the atmosphere. Unlike other locations, there is no sun to rewarm the ground in the winter. Secondly, in certain wind patterns, there is little mixing of air between that closest to the ground, and that 50 or 100m above. So often our coldest days in winter at ground level are those that are still days with little wind to mix the cold air at ground level with warmer air up higher, and no clouds to reflect the heat back. If we climb the meteorological tower to 30m we can at times get above the invesion layer, where the air temp is much warmer by up to 20 degrees.

The wind patterns of the continent are interesting. Whilst on average it is one of the windiest continents on earth, the interior differs vastly from the coast. The wind accelerates as it descends in altitude heading down the edges of the plateau generating the infamous katabatic winds that can batter the coast, up to the record of 327 km/h reached at the French Dumond d’Urville Station on the East Antarctic coast in 1972. However in the interior, we essentially always have some wind, but is never blowing a gale. The direction of the wind is fundamental for determining local weather conditions.

As we lie at 90.000 degrees south, from here everywhere is ‘north’, which doesn’t help that much in trying to determine what way to refer to different parts of the continent. Therefore the grid system is used with grid north being 0 degrees longitude (ie to Greenwich), grid south 180 degrees east (towards New Zealand), grid west 90 degrees west (towards the Americas) and grid east 90 degrees east (towards Asia).

To our ‘east’ lies the highest and largest bulk of Antarctica, as the continent is not centred directly over the pole. This higher area of landmass is also further from the coast, and therefore the coldest region. It is in the interior of this, where the ‘Pole of Inaccessibility’ lies – the point on the continent furthest from the coast. Near this point lies the Russian Vostok station which has the honour of being the coldest inhabited place recorded, at a nippy -89.3 degrees Celsius. There have now been colder temperatures measured high on the ridges of east Antarctica, but these are not inhabited…yet.
As East Antarctica is uphill from us, the winds tend to flow from there, and with in comes cold dry weather. If the winds switch to the north west, now flowing from the closer Weddell sea, the ocean moderates the temperature resulting in warmer weather, but also carries more water vapour meaning cloudy conditions. The weather chart will look warmer on the screen but the psychological aspect of seeing cloudy weather means you often think it is colder outside.

With an all time recorded high of -12 degrees C and a minimum of -83C, the station maintains the record of the second coldest inhabited place on the earth. Summer average temperatures sit around -30 or -40C and as the sun sets, taking with it its radiant heat, the temps fall to around -55 to -65. Recently, we had an especially cold snap, with the ambient temps reaching -75C with windchill on top of that.

Windchill calculations are a contentious issue, with the original science underpinning traditional calculations being debated. Revisions have occurred and now better reflect the impact of wind on the human body, but they remain a point of debate. Is it worse to be in -75C weather with no wind, or -50C weather with 20 knots of wind? The seasoned veterans who spend a lot of time outside down here over winter seem to think that the calculations have a reasonable degree of validity, as the perceived temperature accounting for windchill can be so much colder than what is felt without. A part of it depends on how you dress – whether you clothes are better at windbreaking or have thick insulating layers will to a mild degree dictate how you perceive these differences. But at the coldest we had recently of -75C, the windchill pushed it down to -105C and that wind certainly had a bite to it. Windchill only accounts for rate of loss of temperature – ambient temperature of -75C with windchill of -100C means that you should lose heat at the same rate that you would if it was -100C without wind. However, if you were not a warm blooded mammal, the coldest you could get would still be -75C, but you will just get there faster than if there was no wind.

You do get adjusted to the temperature pretty promptly, or else going outside would remain a very unpleasant experience. As a lot of the station inhabitants get by without going outside at all if they don’t want to, it is often humorously ironic to partake is discussions in the galley about the weather with people who have just been outside.
‘What’s the weather like outside today?’
‘Oh, it’s pretty warm out there (being serious)’
(Looking at weather screen) ‘Oh yeah, its -50C at the moment’
When the weather is always below 0C, you can make some efficiencies such as referring to all temps without the minus in front of it. It also makes comments such as ‘it’s freezing outside’ relatively redundant. But when someone says ‘it’s cold outside’, at least there is more of a spectrum to cold, and like, reeeeaaaal cold.

When -50C seems like a warm day, you know that your standards have changed somewhat! You can notice the difference when you go outside. Your face doesn’t feel like as many needles are jabbing it if you aren’t wearing your balaclava. Your layers of wrapping up are resistant to getting cold to your core. But a 20 degree swing from -50 to -70 is much less discernable than going from +10 to +30C. This is in part because at either -50 or -70, if you aren’t wrapped up to the nines when you go outside, either way will result in frostbite or hypothermia if you are outside for more than a couple of minutes.

A typical clothing get-up for going outside normally consists of:
– base clothing of merino long sleeve top and cotton or wool trousers
– Thick woolen socks
– ‘FDX’ cold weather boots with woolen bootie liners
– Carhart heavy duty padded over trousers
– Woolen or polar-fleece sweatshirt
– ‘Big Red’ Canada Goose down jacket
– Woolen balaclava
– Woolen beanie
– Polar-fleece neck gaiter
– Goggles with non-tinted lens for winter months
– Marmot 8000m mitts with down liners
With this set up, no skin should be left exposed and even in the coldest temperatures, you can last an hour outside, depending on activities. The biggest variable I have found is what you are holding. Touching metal even through top of the line gloves, such as a camera tripod, sled handle, or scientific equipment sucks the heat out of your hands at a rapid rate. This addition of conduction of heat away along with normal radiation and convection can be profound and result in chilly digits in a matter of a couple of minutes. Mitts tend to keep your hands a lot warmer than gloves, as the individual fingers can keep their adjacent fingers warm rather than the heat being lost as radiation.

If you have to take your hands out of gloves to do work such as adjusting buttons on a camera, screwing up bolts or other fine-motor skills that are not compatible with heavy duty mitts, your hands can take a hammering.

The most common place for people to get frostbite is around the face though. The contours of the face, with overlapping balaclavas, goggles and neck gaiters often means that small gaps are missed around the eyes, nose or mouth. Meal-time conversation will often turn to the inflamed skin on the person’s face opposite you at the table, who didn’t quite cover up completely. These mild variants tend to resolve within a few days, and are not a lot different to get a spot of sunburn on your nose.
I have found the biggest problem being regarding wearing a balaclava. As we breath in, our upper airway humidifies the air, and when we exhale, it tends to condense on the balaclava. This after a while saturates the balaclava and it can then freeze. My attempt at growing a mangy beard has protected my chin and lips from being plastered to my balaclava, but my nose has suffered a few times, enough so that it is lucky I haven’t picked up the nickname Rudolf.

It is cold enough outside that if you throw a glass of boiling water up in the air, it freezes into a fine mist before descending.
With ambient temperatures always colder than a freezer, food storage is never an issue. Other than a few liquids, almost all food is stored in non heated areas, with the requirements for the upcoming week, being brought up on a weekly basis to defrost before being able to be used. Defrosting your icecream for half a day before you can put it in the freezer to be eaten is a novelty. The phrase ‘First world problems’ doesn’t quite seem congruous here, so instead the common answer to any gripes is ‘it’s a harsh continent…’

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One Response to A tad on the chilly side

  1. Noel Munford says:

    Well and interesting read. By the way it’s 15 degrees C here.LOL

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