Volumetric T,S-analysis of the Barents Sea Waters
Sergei Mukhametov(1), Victor Arkhipkin(1,2)
and Fedor Tuzov(1,3)
(1)
(2)
(3)
Lomonosov MSU, 119991 Moscow, Russia
Telephone: +7(495)9392215
Email: puffin@bk.ru,
Email: victor.arkhipkin@gmail.com,
Email: fedor-tuz@mail.ru
Abstract
One of the major objectives of the study the World Ocean is currently
determining its average characteristics. Origin and evolution of the composition of
ocean waters, changing the energy budget and dissolved substances, long-term
fluctuations of climate variability parameters of the ocean-atmosphere system in the
seasonal and synoptic scale - all these problems require the knowledge of the
characteristic values of the hydrological characteristics and energy potentsiadov oceans
and their parts.
The present work is devoted to the interannual variability of the thermohaline
characteristics of the Arctic seas. Due to increased attention to the Arctic because most
rapid climate change processes there is a need in the multilateral analysis of the data in
this region. Today, on the Arctic region gathered a large amount of data, but their
distribution is very uneven. One of the most affluent areas of the data is in the Barents
Sea.
Increased melting of ice in recent years has led to the formation of desalinated
water masses in the polar regions of the oceans that extend further. These water masses
are not typical for their areas of distribution, to influence the ocean circulation,
contacting with adjacent water masses. Desalination surface aquifers leads to blockage
of energy lower horizons with the atmosphere, reduce the intensity of winter
convection. Desalination of water of the North Atlantic are described in [Dickson,
Yashayaev 2002; Dickson, Curry 2003], but on the Arctic region, information about the
complex impact of desalination is not as detailed, and usually is the basin of the Arctic
Ocean, rather than the specific area.
The term "water mass" was accurately defined A.D.Dobrovolskiy as "some
relatively large volume of water, which is formed in a specific area of the ocean - the
hearth, source of supply, which has for a long time almost constant and continuous
distribution of physical, chemical, biological characteristics that make up a single
complex and distributed as one single entity "[Mamaev 1987].
The study long-period variability of water mass is to extract regularities of their
transformation through the study of the variability of the main determining its
parameters. Process variability studied using characteristic diagrams of state - bulk TS
diagrams, which were introduced Montgomery, Cochrane and Pollack. [Mamaev 1987].
The relevance of this study is a comparative assessment of the current dynamics and
identify variability adds to the pool of Atlantic waters of the Arctic seas. They largely
determine the vertical heat exchange conditions of the Arctic Ocean, the water
circulation of the seas of the western sector of the Russian Arctic, water exchange with
the open part of the Arctic Ocean.
Introduction
The Barents Sea is located in the north-western part of the Eurasian shelf of the
type of the continental margin of the seas, have good communication with the adjacent
waters to the west and north. The Barents Sea has clear limits in the south and the east
part, on other parts of the border are contingent lines held on the shortest distance
between shore points. Western border of the sea is the line cape Southern (Svalbard) Bear Island - North Cape. The southern border runs along the sea coast and the line cape
Holy Nose - cape Kanin Nos, separating him from the White Sea. From the East Sea is
limited to the west coast of Vaigach and Novaya Zemlya and then line cape Desire cape Kolzat (Graham Bell Island). In the north of the sea border runs along the northern
edge of the archipelago of Franz Josef Land to cape Mary Harmsuort ( Alexandra Land
Island) and further through the Victoria Island and goes to the White cape Lee-Smith
North East Land Island (Svalbard).
Its area is 1424 thousand km2, the volume of 316 thousand km3, the average
depth of 222 m, maximum depth - 600 m ["Sea USSR" 1990]. Barents Sea coast, as the
mainland and the island, quite strongly dissected by numerous fjords, particularly in the
north-western part. The river flow is about 163 km3 / year. Of this amount, on the river
coast of Norway and the Kola Peninsula accounts for about 10% of the total runoff.
The bottom of the Barents Sea has a slight slope from east to west. Depths, mainly from
100 to 350 m, and near the border with the Norwegian Sea increased to 600m. Many
seamounts and depression have an impact on the redistribution of water masses.
Decisive influence on the thermal and salinity regimes of the western sector of
the Barents Sea has the North Atlantic Current, bringing warm salty Atlantic water in
Barents Sea basin. Crossing the threshold of the Faroe-Iceland, the North Atlantic
Current should be in the north-east along the coast of Norway (for Norwegian), which
then branches into the West Spitsbergen, flows into the Arctic basin to the west of
Spitsbergen and the North Cape, flows into the Barents Sea west (Figure 1). The waters
of the North Cape Current, past the Barents Sea and entered the Arctic basin, called the
Barents Sea branch of the Atlantic water mass. The waters of the West Spitsbergen
Current, after receipt of the Arctic basin, called Fram branch.
Atlantic water mass is the most stable water mass, maintains its characteristics
over the whole year, and are characterized by high values of temperature and salinity. In
the surface layer of the characteristic values are 34.5-35.0‰, and 3-5 ° C in winter, 810°C in the summer (Fig. 2); with depth the temperature drops, but throughout the year
remains positive, not falling below 3°C at depths of up to 200 m. To the east of the Kola
meridian (33°30’ E), the temperature of the Atlantic water drops to 1-3°C in the surface
layer and up to 1°C on the horizon 200 m. This water mass is released as a transformed
Atlantic water, which is different from the Barents Sea waters are very few. Atlantic
water flows into the Barents Sea through its northern border. They are distributed in the
form of subsurface flow, the maximum temperature is (1.5°C) occur at depths of 100200 m [Kosarev, 1999].
Fig.1: Map of the currents in the Barents Sea (http://www.eoearth.org)
Barents Sea water - formed as a result of the transformation of the Atlantic
waters under the influence of local conditions. These waters are characterized by low
temperature and high salinity.
Fig. 2: T,S diagram for the northern part of the Barents Sea, Atlantic water mass
Fig. 3: T,S diagram for the southern region of the Barents Sea, Atlantic water mass
Arctic water flows in the form of surface currents from the north. It is a negative
temperature water and low salinity. In winter, the Arctic waters are absent in summer
are common in the northern Barents Sea.
Coastal waters. Comes from the continental runoff, the waters of the White Sea,
and the coastal course along the Norwegian coast of the Norwegian Sea. In winter, the
coastal waters are noted only in the surface layers, and in the summer the entire
southern part of the area is completely filled with them.
On the western border of the Barents Sea, thanks to good connections to the
Norwegian Sea, there is an active exchange of water. Mainly, it is in receipt of Atlantic
waters forming Nordkapp current in the south-western part of the Barents Sea. In
general, due to the small effect of river flow and active water exchange with the ocean,
the chemical composition of the waters of the Barents Sea close to the composition of
ocean waters, and as a result the value of the salinity differ slightly from the average
salinity of the ocean. The highest salinity at the sea surface – 35.0 ‰ - is observed in
the western part of the area. From west to east there is a tendency to reduce the salinity
of 32.0-33.0 ‰. Also, there has been a slight decrease in salinity (34.5 ‰) in the
northern part, due to the melting of ice (Fig. 6). The distribution of salinity has seasonal
variability. In autumn and winter in the waters salinity is high (32.5-35.0 ‰) (Fig. 7).
This is due to the influx of Atlantic waters to the west, ice formation in the north,
extremely small river runoff in the coastal region.
The temperature distribution also has a seasonal dependence. In the winter in the
south and south-west surface temperature is 4-5°C (Figure 5), in the central areas 0-3o,
and in the northern and north-eastern parts of it is close to freezing point. In summer,
the temperature distribution observed latitudinal dependence. In the southwestern part
of the Barents Sea surface temperature reaches a value of 8-9°C (Figure 4), in the
central part it varies between 3°C to 5°C, in the north the temperature is around 0°C.
The distribution of temperature in the water is influenced by many local factors. To the
south-western part of the Barents Sea, the main factor is the impact of Atlantic waters in
this regard, the temperature in this region is slightly decreased with depth to the bottom
(Figure 3). In the north-eastern part to a depth of 200m there are negative temperatures,
the temperature rises to more deeply because of 1°C Atlantic waters, extending to the
bottom layer in the north-east. In summer, this region is experiencing a cold
intermediate layer at depths of 50 to 100m.
The circulation of the Barents Sea due to several factors. One of the highlights is
a strong warm current from the Norwegian Sea, which forms during the Nordkapp. It
runs between Bear Island and North Cape from the south-west to east at a speed of up to
25 cm/s. Then, it branches into Murmansk and Murmansk coastal currents. Coastal
Murmansk during a speed of 15-20 cm/s, spreading along the coast of the Kola
Peninsula, combined with the White Sea passage at the throat of the White Sea, and
moves east to Kolguev. Then Murmansk coastal current is divided into two branches Kanin and Kolguev flow. The first is along the coast in the south-eastern part of the
area, the second - in the north-east to the coast of Novaya Zemlya. Murmansk passes
over the northern coastal Murmansk and forms of the West during the Novaya Zemlya.
From the northeast to the island of Hope suitable for Perseus, giving rise to the Bear
cold flow rates of up to 50 cm/s.
Fig. 4: The temperature distribution in the
surface layer of the Barents Sea in
summer
Fig. 5: The temperature distribution in
the surface layer of the Barents
Sea in winter
Fig. 6: Distribution of salinity (‰) in the
surface layer of the Barents Sea in
the summer salinity distribution
Fig. 7: Distribution of salinity (‰) in the
surface layer of the Barents Sea in
winter
T,S-analysis of the Barents Sea waters
As sources of oceanographic data were used the database of measurements of
oceanographic (World Ocean Database) National Oceanographic Data Centre USA
(NODC) and an electronic atlas of the oceans edition 2013 (WOA)
[http://www.nodc.noaa.gov]. The Atlas of temperature and salinity of the water located
in the centers 15 minute spherical trapezoids. The depth of from 0 m to 100 m in 5 m,
from 100 m to 500 m in steps of 25 m, from 500 m to 1500 m in increments of 50 m.
Let me remind you that the maximum depth of the Barents Sea about 600 m.
To construct the bulk of statistical TS diagrams interpolated data on temperature and
salinity were sorted by TS classes. For each TS class each cut were counted amounts
held by this class in the amount of sea water. The volume of water in the Barents Sea
have been evaluated in the temperature range (-1.8°C to 9°C) with a step 0.2°C, the
salinity range of 30-36 ‰ in increments of 0.1 ‰. The largest volume of water
correspond to the following temperatures, salinity ranges (Table 1-3):
Table 1. The temperature of the cell with the maximum amount of water in the Barents
Sea for months.
Month
Central temperature cell
January
February
March
April
May
June
July
Augustus
September
October
November
December
-0.3°С
-0.5°С
-0.5°С
-0.5°С
-0.9°С
-0.9°С
-0.9°С
-0.7°С
-0.7°С
-0.7°С
0.3°С
-0.3°С
The volume of water mass,
cubic km
17264
17628
19339
18506
20055
16970
20783
24337
24001
20705
14270
16024
Table 2. Salinity cell with the maximum amount of water in the Barents Sea for
months.
Month
January
February
March
April
May
June
July
Augustus
September
October
November
December
Central salinity cell
34.85‰
34.95‰
34.95‰
34.85‰
34.85‰
34.95‰
34.95‰
34.95‰
34.85‰
34.95‰
34.95‰
34.95‰
The volume of water mass,
cubic km
70637
62801
59914
69535
70955
75064
77990
71470
68673
76666
96754
76723
Table 3. The average temperature and salinity of the water in the Barents Sea for
months.
Month
January
February
March
April
May
June
July
Augustus
September
October
November
December
T, °C
0.889
0.800
0.542
0.462
0.424
0.775
0.981
1.343
1.492
1.445
1.615
1.169
S, ‰
34.825
34.797
34.786
34.808
34.821
34.794
34.739
34.716
34.700
34.715
34.748
34.803
Conclusions
The Barents Sea - a water area, released in the oceans of its thermohaline
structure. The highest average sea temperature in November is due to strong winter
convection. Surface waters of the sea, cools, increases its density and sink to
considerable depths, taking up a large amount of sea water. Due to the fact that the
temperature of the surface water in the summer season above average sea temperature
rises. Well stratified structure of water temperature in August and September,
November and December starts to blur. Salinity is the structure, on the contrary, it
becomes more stable and less stable in the fall in the spring.
This work was supported by a contract with the Russian Science Foundation
(contract №14-37-00038)
Key words
Barents Sea, volume, temperature, salinity, T,S-analysis
References
Kosarev A.N., Zalogin B.S. (1999) Моря. М. «Мысль»(in Russian)
Mamaev О.И. (1987) Термохалинный анализ вод Мирового океана. Л.
Гидрометеоиздат, (in Russian)
Проект «Моря СССР» (USSR Seas) Том 1. Баренцево море.
Гидрометеорологические условия. Л. Гидрометеоиздат, 1990 (in Russian)
Вып.1
Curry R., Dickson B.,( 2003) “Achange in the freshwater balance of the Atlantic Ocean
over the past four decades”, Nature, Vol.426, pp.826-829.
Dickson B., Yashayaev I. (2002 ) “Rapid freshening of the deep North Atlantic Ocean
over the past four decades”, Nature, Vol. 416, pp.832-836.
http://www.nodc.noaa.gov - World Ocean Atlas 2013 version 2 (WOA13 V2)