Arctic Weather and the Polar Environment
As Santa Claus and his reindeer will tell you, the north pole is a cold, dry and windy place only fit for the Abominable Snowman.
All myths aside, the Arctic polar region is generally kinder and gentler than its southern counterpart, Antarctica. That’s because the most northern part of the Arctic is open ocean, which retains more heat and keeps the north warmer than the Antarctic.
How warm is it? Not very. By definition, “polar” indicates that it’s below freezing for more than half the year. Polar climates basically lack warm summers. Trees don’t grow, but glaciers and ice sheets do.
How dry is it? Like the Sahara, only colder. Northwest Greenland gets around 75mm of precipitation a year. That’s not much.
The Arctic is hard to describe because it covers such a huge area. One way to define the Arctic is by its climate and ecology. The Arctic is everything north of the 10°C (50°F) summer isotherm, which represents the average temperature in July. An isotherm indicates a line of equal or constant temperature, and it’s used to show temperature distributions on weather maps. The summer isotherm is basically tree line for most of the Arctic, though a lot of Arctic maps also include the Subarctic when drawing boundaries around the northern polar region.
The Arctic Circle (66° 33’N latitude) is near the limit of the midnight sun and the polar night. The Arctic winter is around nine months long, when the polar night lasts 20-24 hours. The midnight sun occurs in the summer, when the sun is still visible at midnight.
The Ocean Effect
The Arctic Ocean, which is actually several seas coming together, is surrounded by a broad and shallow continental shelf. Pack ice still covers nearly half of the Arctic Ocean even in the summer, when the southern peripheral ice recedes. That means most of the Arctic waters are static.
Think of the Arctic Ocean a marine parfait – it’s multi-layered. The upper layer is the frozen crust. Below that lies a rich, thin layer of water that is fed mostly from Siberian rivers. The next water layer is deeper and warmer, and it comes from the Atlantic Ocean. Finally, an even deeper layer that sits below 800 meters (2,625 feet) is very cold and still.
The most impressive glaciers in the northern hemisphere are formed by rivers of ice that come from the Greenland ice cap. The largest of these calve off huge icebergs into Disko Bay on the west coast. Smaller icebergs are created in Scoresby Sound of East Greenland. Svalbard, Spitsbergen is also a great place to see Arctic glaciers, river beds and ice grottos up-close and personal.
The Arctic waters manage to support plenty of wildlife, especially in the fringe areas near land, where the continental shelf is shallow and the peripheral ice melts in the summer. The nutrient-rich surface waters promote seasonal plankton blooms that nourish fish, birds, seals, and whales during their summer grazing. The Arctic Ocean’s warming effect and the surrounding land masses provide habitat for plants as well as user-friendly travel and migration routes for the local animal populations.
A Land Of Extremes
The Arctic region sees big fluctuations in climate and environment, and the ecological balance is fragile and slow to recover. Plants and animals need a lot of therapy to adapt to this stressful life.
In the winter, anticyclones – high pressure systems that rotate clockwise – dominate the region’s weather patterns. In the summer, these systems decrease and warmer, wetter ocean air visits the region.
During the winter, it’s cold, dark and the temperature rarely gets above freezing. Summer hits quickly with nearly continuous daylight from May to July, and that’s when everything comes to life in the Arctic. There’s a frenzy of growth and activity. Plants bloom and insects take over during that brief warm and sunny spell. Animals and migratory breeding birds take advantage of those few months. Spring and fall are mere blips on the Arctic radar.
[TRIP TRIVIA: The coldest spot in the north is NOT the North Pole. It’s near Verkhayansk, Siberia! That’s because the interior of Asia’s large northern landmass is too cold to hold moisture – it’s just a big frozen desert – while the Arctic Ocean is comparatively warmer.]
Two Climates In One
There are two general types of polar climate:
• The “ice-cap” or “perpetual frost” climate, which has sub-freezing temperatures all year.
• The tundra, where at least one month’s average temperature is above freezing.
To complicate matters further, tundra comes in three flavors: Arctic, Antarctic, and Alpine tundra, which is found in mountainous terrain where cold temperatures are due to high elevation regardless of latitude.
Antarctica is the only continent on earth where a polar climate dominates. The Arctic is more diverse.
In the Arctic, tundra is found in the southern regions, and ice caps are further north. A lot of the Arctic region is permanently covered by solid or drifting pack ice. That permanent ice is a 3 to 4-meter thick ice sheet covering approximately 8 million square kilometers north of Svalbard and Franz Josef Land. It’s tough to impossible for plants and animals to live under that polar ice, considering very little sunlight penetrates through to the water. Only a few species inhabit the very far north.
Tundra covers most of northern Canada and Alaska, parts of northern Siberia, northern Iceland, and the extreme northeastern coast of Scandinavia east to the Bering Strait. Tundra is known for its low temperatures and short growing seasons – that means no (or very few) trees grow there. Grasses, mosses and lichens are the big three in the Arctic tundra. Plants are very slow-growing and long-living. They are stunted in size compared to their warm-weather relatives. Even the tiniest plants can be incredibly old.
Year-round permafrost means that the ground material stays at or below freezing for two or more years. Ice doesn’t have to be present, though it often is. An active layer of ground on the surface (on top of the permafrost) that thaws seasonally during the short summer can support plant life.
Typically, ground temperature varies less than air temperature from season to season. Temperatures are also colder the deeper you go into the ground. In some of the “warmer” climates, where air temps hover just below and around freezing, you see discontinuous permafrost. That means permafrost only forms in sheltered areas that often face north, so there are patches of permafrost that might not go very deep under the surface.
[TRIP TRIVIA: Want to take world-class wildflower photos? Go to the Arctic! Though they bloom fast to take advantage of the condensed summer sunshine, there are over 300 species of low-growing flowering plants. Compare that to only two flowering species in Antarctica!]
Ice Cap, Anyone?
In polar language, an ice cap is a dome-shaped ice mass that covers less than 50,000 square kilometers of area, usually on a mountain or at high altitude. If the ice covers more than 50,000 km2, it’s called an ice sheet.
In many Canadian dialects, an ice cap is an iced cappuccino – a fun and frothy drink of the coffee variety that comes in mugs small enough to wrap your fist around. While standing on a polar ice cap, a hot cap(puccino) might be more appropriate.