Subarctic climate: Wikis

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Regions having a subarctic climate (also called boreal climate) are characterized by long, usually very cold winters, and short, cool to mild summers. It is found on large landmasses, away from the moderating effects of an ocean, generally at latitudes from 50° to 70°N poleward of the humid continental climates. These climates represent Köppen climate classification Dfc, Dwc, Dfd and Dwd.

This type of climate offers some of the most extreme seasonal temperature variations found on the planet: In winter, temperatures can drop to −40 °C (−40 °F) and in summer, the temperature may exceed +30 °C (86 °F). However, the summers are short; no more than three months of the year (but at least one month) must have a 24-hour average temperature of at least +10 °C (50 °F) to fall into this category of climate. The subarctic climate is a subset of the continental climate. The subarctic climate is found in the following areas[citation needed]:

The Southern Hemisphere, which has no large landmasses in the upper-middle latitudes that can have both the short but well-defined summers and severe winters that characterize this climate, has no locations with this climate.

With 5-7 consecutive months where the average temperature is below freezing, all moisture in the soil and subsoil freezes solidly to depths of many feet. Summer warmth is insufficient to thaw more than a few surface feet, so permafrost prevails under large areas. Seasonal thaw penetrates from 2 to 14 ft (0.6 to 4 m), depending on latitude, aspect, and type of ground.[1] Some northern areas with subarctic climates located near oceans (southern Alaska and the northern fringe of Europe), have milder winters and no permafrost, and are thus more suited for farming.

The frost-free season is very short, varying from about 45 to 100 days at most, and a freeze can occur during any month in many areas. Vegetation in a subarctic climate is generally of low diversity, as only hardy species can survive the long winters and make use of the short summers. Trees are mostly limited to ferns and evergreen conifers, as few broadleaved trees are able to survive the very low temperatures in winter. This type of forest is also known as taiga, a term which is sometimes applied to the climate found therein as well. Even though the diversity may be low, numbers are high, and the taiga (boreal) forest is the largest forest biome on the planet, with most of the forests located in Russia and Canada. The process by which plants become acclimated to cold temperatures is called hardening

Agricultural potential is generally poor, due to the natural infertility of soils and the prevalence of swamps and lakes left by departing ice sheets, and short growing seasons prohibit all but the hardiest of crops. (Despite the short season, the long summer days at such latitudes do permit some agriculture.) In some areas, ice has scoured rock surfaces bare, entirely stripping off the overburden. Elsewhere rock basins have been formed and stream courses dammed, creating countless lakes.[1]

Should one go poleward or even toward a polar sea, one finds that the warmest month has an average temperature of less than 10°C (50°F), and the subarctic climate grades into a tundra climate even less suitable for trees. Equatorward or toward a lower altitude, this climate grades into the humid continental climates with longer summers (and usually less-severe winters); in a few locations close to a temperate sea (as in North Norway and southern Alaska), this climate can grade into a short-summer version of an oceanic climate as the sea is approached.

Contents

Precipitation

Most subarctic climates have very little precipitation, typically no more than 15 inches (38 cm) over an entire year. Away from the coasts, precipitation occurs mostly in the warmer months. Low precipitation, by the standards of more temperate regions with longer and warmer winters, is typically sufficient in view of the very low evapotranspiration to allow a water-logged terrain in many areas of subarctic climate.

A notable exception to this pattern is that subarctic climates occurring at high-altitudes in otherwise temperate regions have extremely high precipitation due to orographic lift. Mount Washington, with temperatures typical of a subarctic climate, receives an average rain-equivalent of 101.91 inches of precipitation per year.[2]

Locations with subarctic climates

Sample locations with such climates[3]:

Sample locations with the extreme Dfd climate include:

Charts of Selected Cities

Yellowknife
Climate chart (explanation)
J F M A M J J A S O N D
 
 
14
 
-22
-31
 
 
13
 
-19
-28
 
 
13
 
-11
-23
 
 
11
 
0
-11
 
 
19
 
11
1
 
 
27
 
18
9
 
 
35
 
21
12
 
 
41
 
18
10
 
 
33
 
10
4
 
 
35
 
1
-4
 
 
24
 
-10
-18
 
 
16
 
-20
-28
average max. and min. temperatures in °C
precipitation totals in mm
source: Environment Canada[4]
Anchorage
Climate chart (explanation)
J F M A M J J A S O N D
 
 
17
 
-6
-13
 
 
19
 
-3
-11
 
 
17
 
1
-8
 
 
13
 
7
-2
 
 
18
 
13
4
 
 
27
 
17
8
 
 
43
 
18
11
 
 
74
 
17
9
 
 
73
 
13
5
 
 
53
 
4
-2
 
 
28
 
-2
-9
 
 
27
 
-4
-12
average max. and min. temperatures in °C
precipitation totals in mm
source: The Weather Channel[5]
Verkhoyansk
Climate chart (explanation)
J F M A M J J A S O N D
 
 
5
 
-51
-54
 
 
5
 
-49
-50
 
 
3
 
-25
-39
 
 
5
 
-7
-23
 
 
8
 
9
-5
 
 
23
 
16
9
 
 
28
 
19
8
 
 
25
 
14
4
 
 
13
 
6
-3
 
 
8
 
1
-19
 
 
8
 
-35
-40
 
 
5
 
-49
-50
average max. and min. temperatures in °C
precipitation totals in mm
source: World Weather[6]
Samedan
Climate chart (explanation)
J F M A M J J A S O N D
 
 
30
 
-2
-18
 
 
25
 
0
-17
 
 
31
 
3
-12
 
 
44
 
6
-6
 
 
81
 
12
-1
 
 
87
 
16
2
 
 
89
 
18
3
 
 
99
 
18
3
 
 
72
 
15
0
 
 
59
 
11
-4
 
 
54
 
4
-11
 
 
31
 
-2
-16
average max. and min. temperatures in °C
precipitation totals in mm
source: MeteoSchweiz[7]
Luleå
Climate chart (explanation)
J F M A M J J A S O N D
 
 
32
 
-7
-13
 
 
26
 
-6
-13
 
 
23
 
-1
-9
 
 
18
 
4
-3
 
 
23
 
11
2
 
 
32
 
17
9
 
 
42
 
20
12
 
 
42
 
18
11
 
 
31
 
12
6
 
 
34
 
6
0
 
 
31
 
-2
-6
 
 
27
 
-6
-11
average max. and min. temperatures in °C
precipitation totals in mm
source: World Weather Information[8]
Kiruna
Climate chart (explanation)
J F M A M J J A S O N D
 
 
30
 
-11
-22
 
 
26
 
-9
-20
 
 
26
 
-5
-18
 
 
27
 
-1
-9
 
 
34
 
8
-2
 
 
49
 
15
5
 
 
86
 
18
7
 
 
74
 
15
5
 
 
49
 
10
1
 
 
47
 
-2
-11
 
 
42
 
-7
-13
 
 
34
 
-9
-20
average max. and min. temperatures in °C
precipitation totals in mm
source: SMHI[9]

References

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Simple English

Regions having a subarctic climate (also called boreal climate) are characterized by long, usually very cold winters, and brief, warm summers. It is found on large landmasses, away from the moderating effects of an ocean, generally at latitudes from 50° to 70°N. Due to the absence of any large landmasses at such latitudes, it is not found in the Southern Hemisphere. These climates represent Köppen climate classification Dfc, Dwc, Dfd and Dwd.

This type of climate offers some of the most extreme seasonal temperature variations found on the planet: In winter, temperatures can drop to −40°C (also −40°F) and in summer, the temperature may exceed 30°C (86°F). However, the summers are short; no more than three months of the year (but at least one month) and must have a 24-hour average temperature of at least 10°C (50°F) to fall into this category of climate. The subarctic climate is a subset of the continental climate. The subarctic climate is found in the following areas:

With 5-7 consecutive months where the average temperature is below freezing, all moisture in the soil and subsoil freezes solidly to depths of many feet. Summer warmth is insufficient to thaw more than a few surface feet, so permafrost prevails under large areas. Seasonal thaw penetrates from 2 to 14 ft (0.6 to 4 m), depending on latitude, aspect, and type of ground.[1] Some northern areas with subarctic climates located near oceans (southern Alaska and the northern fringe of Europe), have milder winters and no permafrost, and are thus more suited for farming.

The frost-free season is very short, varying from about 45 to 100 days at most, and a freeze can occur during any month in many areas. Vegetation in a subarctic climate is generally of low diversity, because only hardy species can survive the long winters and make use of the short summers. Trees are mostly limited to ferns and evergreen conifers, as few broadleaved trees are able to survive the very low temperatures in winter. This type of forest is also known as taiga, a term which is sometimes applied to the climate found therein as well. Even though the diversity may be low, numbers are high, and the taiga (boreal) forest is the largest forest biome on the planet, with most of the forests located in Russia and Canada.

Agricultural potential is generally poor, due to the natural infertility of soils and because of the many swamps and lakes left by departing ice sheets, and short growing seasons allow only the hardiest of crops. (Despite the short season, the long summer days at such latitudes do permit some agriculture.)

There is very little precipitation, no more than 15 to 20 inches over an entire year and, away from the coasts, occurs mostly in the warmer months. Low precipitation, by the standards of more temperate regions with longer and warmer winters, is typically sufficient in view of the very low evapotranspiration to allow a water-sogged terrain in many areas of subarctic climate.

Poleward or even approaching polar seas, the warmest month has an average temperature of less than 10°C (50°F), and the subarctic climate grades into a tundra climate even less suitable for trees.

Sample locations with such climates[2]:

Sample locations with the extreme Dfd climate include:

  • Oymyakon, Russia
  • Verkhoyansk, Russia

References

  1. http://www.fs.fed.us/colorimagemap/images/130.html
  2. http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/climate_systems/subarctic.html

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