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Climate Atlas of Eurasian and North American Arctic regions

Studienarbeit 2001 29 Seiten

Geowissenschaften / Geographie - Phys. Geogr., Geomorphologie, Umweltforschung

Leseprobe

Contents:

1. Introduction

2. Arctic climate stations
2.1. Siberian Section
2.3. Komi-Nanette Section
2.4. Quebec Section
2.5. Central-Canada Section
2.6. Alaska

3. Permafrost and Arctic tree line

4. Conclusions

5. References

6. Appendix

1. Introduction

The following climate atlas will show' the climatic differences between selected arctic regions from Eurasia, or strictly speaking Russia, and North America. The main emphasis will thereby be put on the difference between oceanic (maritime) and continental climate. It will also show the spread of permafrost and the localisation of the Arctic tree line, which both depends on the existing climate.

But what are the differences between oceanic and continental climate? How could the climates be described?

Oceanic climates can be found in coastal regions or a bit more inland on the western side of Eura­sia or eastern parts of North America. They characterise themselves through a high rate of total precipitation - wet climate - and a low annually temperature amplitude - the range between the temperature of the coldest month, normally January on northern hemisphere, and the temperature of the warmest month, normally July. An example for such a climate is shown in Figure la. Here the annually amplitude is [Abbildung in dieser Leseprobe nicht enthalten] and the total amount of precipitation is “9/7 mm”. As you can see, you will always find enough precipitation, so there will be no dry-period. A dry-period is defined as following:

precipitation [mm] < temperature *2 [°C]

As you move inland, away from the western coasts of Eurasia or eastern coasts of North America, the climate will become more continental. This means, that the total precipitation will decrease and the temperature range will increase. A model for an extreme continental climate is given in Figure lb. As you can see the temperature amplitude is [Abbildung in dieser Leseprobe nicht enthalten] - more than two times of that

Abbildung in dieser Leseprobe nicht enthalten

shown in the model for the oceanic climate (Figure la) - and the total amount of precipitation is only “118 mm”. In this example you can also find a dry-period in early summer, where you have little precipitation and a strong rising temperature. Continental climate stations will show a much lower temperature of the coldest month than oceanic stations (here: -45 °C to -17 C).

In areas with continental climates you will have a less depth of snow cover than in oceanic regions for the reason of the lower precipitation.

The arctic can be divided into two vegetation zones, the Taiga, consisting of coniferous forest and the Tundra, normally treeless and covered with lichen and moss. The border between these two zones, which cannot easily marked, will be the Artie tree line.

The lower precipitation, the less snow cover, the colder temperature during winter and the wider annual range, will influence the localisation of the Arctic tree line and also the existence of perma­frost. You can distinguish four types of permafrost by their extension:

Abbildung in dieser Leseprobe nicht enthalten

The Arctic tree line and permafrost will be short discussed in chapter 3.

In the Appendix, the climate-diagrams for each below given station and equivalent maps of the chosen sections and for the locating of the tree line and the permafrost can be found.

2. Arctic climate stations

In this chapter the climatic variation within the arctic will be shown. Therefore four different south-north cross-sections are chosen - each two from Eurasia (Russia) and Northern America (Canada). As a fifth example the most continental climate station in North America, Fort Yukon (Alaska), is shown. For each station, if available, will be given:

- the region and the country within the station is located
- the altitude above sees level
- the mean monthly and annual temperature
- the monthly precipitation and the total amount of it
- the temperature range between the coldest and the warmest month
- the extreme minimum temperature
- the vegetation zone within the station is localised
- the type of permafrost that can be found

The following sections are shown from south to north - the most southern station of each section will be first. In every section, if possible, will be a station, situated close to the tree line and/or the southern limit of Discontinuous permafrost.

2.1. Siberian Section

The first section, which is chosen here, is a section trough Siberia, starting in central Manchuria (China) and moving north up to the Arctic Ocean. The last station, Bulun, is located a bit south of the mouth of the river Lena. This section gives an example of a hyper-continental arctic climate: The temperature range is extremely high - between 41 °C (Harbin) and 63 °C (Verkhoyansk) - and the total precipitation is, excluded the southern cities Harbin and Blagoveshchensk, below 200 mm. In Yakutsk and Verkhoyansk you can find a dry-period in early summer.

Table 1 shows the climate-table for the northern Chinese city of Harbin. It is located within the Asian step, a dry, short grass covered zone of Inner-Asia. Here will you will find isolated perma­frost for the reason that the temperatures in winter are below freezing while having only less snow cover corresponding to the little precipitation. In summer the temperature is about 20 °C, so that the range is 41 °C. The most precipitation will be during summer and for that there is no dry- period (see Figure 2 in the Appendix).

Table 1: Harbin (160 m), Manchuria (China)

Abbildung in dieser Leseprobe nicht enthalten

The next station within the Siberian section is Blagoveshchensk; his data are given in Table 2. This city can be located on the river Amur within the vegetation zone of the Taiga, but you will also recognise trees growing in the mixed-forest of mid-latitudes. Here you have already discon­tinuous permafrost, which means that a larger area is covered by it than in the southern Harbun. Therefore the reason for the existence of permafrost will be the same. The most precipitation will be in summer and the temperature range is 44 °C. This station is also shown in Figure 3 in the Appendix.

Table 2: Blagoveshchensk (142 m), Siberia (Russia)

Abbildung in dieser Leseprobe nicht enthalten

The third Siberian station is Yakutsk (Table 3). It is located in central eastern Siberia within the Taiga vegetation zone. Here the climate is much more continental than in the two above shown southern station of this section. The total amount of precipitation will be only 187 mm and the temperature range is 61 °C. The mean temperature will be much colder during the year and so the permafrost extension can be bigger - more than 50% of the area are covered (continuous perma­frost). But one can still find trees for the reason, that the mean temperature is (still) above +10 °C for more than 30 days (one month). In early summer (May - July) there is a dry-period, where you have not enough precipitation (see Figure 4 in the Appendix). The precipitation maximum can be recognised in August one month after the climate maximum.

Table 3: Yakutsk (102m), Siberia (Russia)

Abbildung in dieser Leseprobe nicht enthalten

Table 4 shows the data for the Siberian climate station Verkhoyansk (northern Siberia), located also in the Taiga vegetation zone. The temperature will be above +10 °C in summer (June­August), so trees can grow, and extremely cold in winter. The rage is 65 °C and the extreme minimum temperature (-70 °C) is the coldest of all here chosen stations. The total amount of pre­cipitation is 102 mm. By that in June you will have a dry-period like in Yakutsk (see Figure 5 in the Appendix). The permafrost type, than can be found is continuous permafrost.

Table 4: Verkhoyansk (100 m), Siberia (Russia)

Abbildung in dieser Leseprobe nicht enthalten

The last and most northern station of this section is Bulun (Table 5). It is already located north of the Arctic tree line in the Tundra-zone. Even the mean temperature in July is above +10 °C, this period may to short for tree-growth and the precipitation may to little. Unfortunately the monthly amounts of precipitation are not available but the total sum is below 100 mm. The temperature range is smaller than in Yakutsk or Verkhoyansk, because of its location not to far from the Arctic Ocean, but still 53 °C. For this station see also Figure 6 in the Appendix-

Table 5: Bulun (35 m), Siberia (Russia)

Abbildung in dieser Leseprobe nicht enthalten

As you can see, moving north through Siberia, the climate will get more and more continental, the temperature range increases while the amount of precipitation decreases at the same time. In this section the Arctic tree line can be located somewhere between the stations of Verkhoyansk and Bulun (mean July temperature is 15 °C respectively 12 °C). The discontinuous permafrost reaches as far south as somewhere between the stations of Blagoveshchensk and Harbin (mean annual temperature is 0,5 °C respectively 3,6 °C). Considering these two locations, you can recognise a distance of about 1.000 km between the Arctic tree line and the southern limit of discontinuous permafrost.

2.2. Komi-Nenets Section

The second chosen section is a section of three stations in the Komi-Nenets area, laying nearly close together and located west of the northern Ural Mountain in Russia. This section gives an example for a sub-continental climate with an intermediate temperature range (about 33 °C) and total amount of precipitation (around 500 mm). The northern station Khoseda-Khard is located at the Arctic tree line.

The most southern station of this short section is Pechora, shown in Table 6. It is located in the northern parts of the Taiga vegetation zone. The mean temperature in summer will be three months above +10 °C and in winter not below -20 °C, the range is 35,5 °C. The precipitation spreads all over the year with a little peak in autumn. Here you can find isolated permafrost. This station is also shown in Figure 7 in the Appendix.

Table 6: Pechora, Komi (Russia)

Abbildung in dieser Leseprobe nicht enthalten

The data for the second station in this section, Usť-Usa, are given in Table 7. It is also situated in the northern parts of the Taiga-zone and has a short summer with temperatures above +10 °C. The precipitation spreads throughout the year with a peak in August and September - the total amount is 495 mm. This station can be located in the area of the southern limit of discontinuous perma­frost. For this station see also Figure 8 in the Appendix.

Table 7: Usť-Usa, Komi (Russia)

Abbildung in dieser Leseprobe nicht enthalten

Table 8: Khoseda-Khard, Komi (Russia)

Abbildung in dieser Leseprobe nicht enthalten

The third station Khoseda-Khard (Table 8), located a bit north of the Arctic Circle, is situated in the area of the Arctic tree line. Here the temperature range is 32,2 °C and the total precipitation 436 mm (spread all over the year). It lies within the zone of discontinuous permafrost. A climate- diagram for this station is drawn in Figure 9 in the Appendix.

In this section the distance between the Arctic tree line, located at Khoseda-Khard (mean July temperature 12,6 °C), and the southern extension of discontinuous permafrost at Ust’-Usa (mean annual temperature -3,2 °C) is much shorter than within the Siberian section. For the fact, that the stations are relatively close together, they are not so much different from each other.

2.3. Quebec Section

One of the two North-American sections chosen in here is going through central Quebec, an East- ern-Canadian province. The section, consisting of three climate-stations, is moving from southeast Quebec to western Quebec, at the coast of the Hudson Bay. It is a very good example for an oce­anic climate in the Arctic. In this region you will find high precipitation (total amount between 962 mm and 631 mm) and a temperature range of around 35 °C. You won’t find any dry-period.

The climate-data for the Quebec section are given for the latest normal-period 1961-1990.

The first station of this section is Manicouagan (Table 9), located east of the Gulf of St. Lawrence. It lies within the Taiga vegetation zone and has the highest precipitation of all here chosen arctic stations. You will find enough precipitation during the whole year but more in summer than in winter. Here you have isolated permafrost, which means that only little areas are affected. This fact is the result of the high rate of precipitation, even in winter, and by that the much higher snow- cover, so that the cold winter-air cannot penetrate the ground. Sometimes, the temperature gets, even it is an oceanic station, very cold, but only for one or a few day. The extreme minimum tem­perature is -51,1 °C. Figure 10 in the Appendix shows the climate-diagram for this station

Table 9:Manicouagan (406 m), Quebec (Canada)

Abbildung in dieser Leseprobe nicht enthalten

Table 10: Nitchequon (536 m), Quebec (Canada)

Abbildung in dieser Leseprobe nicht enthalten

Table 10 shows the data for the station Nitchequon, central Quebec. It lies within the southern zone of Tundra-vegetation, but you will although find some trees, related to the fact, that there a more than 30 days with a temperature above +10 °C. The precipitation is a bit lower (total amount 783 mm) than in Manicouagan, but there will still enough precipitation in winter to form a good snow-cover that prevents most parts of the ground of permafrost. So one will find only isolated permafrost. The temperature range is 36 °C. The climate-diagram is given in Figure 11 in the Ap­pendix.

The last and most northern station of the Quebec-Section is Poste-de-la-Baleine, shown in Table 11. It is situated at the coast of the Hudson Bay in the area of the Arctic tree line and the southern limit of discontinuous permafrost. As you can see, the precipitation is lower than at the two other eli mate-stations but still 631 mm during the year. The temperature range is equal compared to the other stations. For this station see also Figure 12 in the appendix.

Table 11: Poste-de-la-Baleine (16m), Quebec (Canada)

Abbildung in dieser Leseprobe nicht enthalten

Comparing the three climate-stations of the Quebec section, one will find only little differences. In this region, with the most oceanic climate of the chosen cross-sections, the Arctic tree line and the southern limit of permafrost are located nearly close together in the area around Poste-de-la- Baleine (mean annual temperature -4,3 °C, mean July temperature 10 °C) (see Table 11). As you can see, while moving westwards, away from the Atlantic Ocean, the total amount of precipitation will decrease.

2.4. Central-Canada Section

The last chosen section is the Central-Canada section, going from Medicine Hat in the Canadian Prairie close to the border to the United States all the way north to Alert nearly at the top of Elles­mere Island, “the north cape of Canada”. It is the longest section, including ten climate-stations. Here you will have a continental climate and find differences between the stations within this sec­tion. The Temperature range varies form 32,5 °C in Medicine Hat up to 44,0 °C in Baker Lake (southern Northwest Territories) and the total amount of precipitation is between 489,4 mm at La Ronge (central Saskatchewan) and 131,4 mm at Resolute Airport (central Northwest Territories). The data for the Canadian climate-stations are given for the latest normal period 1961-1990.

The most southern station of this section is Medicine Hat (Table 12) in Southeast Alberta, one of the so-called Canadian “Prairie-provinces”. It is situated within the North American Prairie, a vegetation zone consisting of wide-open long grass covered plains. Here you won’t find any per­mafrost - the station lies at to southern latitude. Although the mean annual temperature is +5,1 °C, some winter day might be very cold - the extreme minimum is -46,1 °C. In August, you can rec­ognise a small dry-period (see Figure 13 in the Appendix). The most precipitation will be recog­nised in early summer.

Table 12: Medicine Hat (717 m), Alberta (Canada)

Abbildung in dieser Leseprobe nicht enthalten

[...]

Details

Seiten
29
Jahr
2001
ISBN (eBook)
9783640133680
ISBN (Buch)
9783640135356
Dateigröße
8.6 MB
Sprache
Englisch
Katalognummer
v113747
Note
1,7
Schlagworte
Climate Atlas Eurasian North American Arctic Ecological Historical Biogeography Alpine Regions

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Titel: Climate Atlas of Eurasian and North American Arctic regions