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    Arctic Tides

    Encyclopedia Arctica 7: Meteorology and Oceanography

    Arctic Tides

    001      |      Vol_VII-0613                                                                                                                  

    (Jonas Ekman Fjeldstad)


            The first attempt to give a survey of the tides in the arctic regions

    was made by Rollin A. Harris in his “Arctic Tides” (1911). But the available

    tidal information was at that time very meager, and the results naturally

    uncertain, since no Observations from the Siberian coast were known. The pat–

    tern of cotidal lines which he drew for the Arctic Sea has not been confirmed

    by later observations.

            Important tidal information was gathered by the Norwegian North Polar

    Expedition with the Maud , 1918-1925. The scientific leader of the expedition,

    Dr. H. U. Sverdrup, made tidal observations at Cape Chelyuskin, Aion Island,

    Cape Serdts Kamen, and Four Pillar Island, and besides these observations the

    expedition also carried out numerous observations of tidal currents, and some

    attempts were also made to determine tidal range on the shelf by means of

    hourly soundings.

            The observations from Cape Chelyuskin and Aion Island showed conclusively

    that the cotidal map of Harris could not be correct. A new system of cotidal

    lines was constructed by the present writer in 1923, and H. U. Sverdrup also

    drew a system of cotidal lines for the shelf. Still the tidal information

    from the arctic regions is very incomplete, and it is not safe to draw cotidal

    lines across the Polar Sea. Some details of the propagation, however, may

    be given.

    002      |      Vol_VII-0614                                                                                                                  
    EA-Oc. Fjeldstad: Arctic Tides


    Semidiurnal Tides in the North Polar Sea

            The semidiurnal tide-producing potential vanishes at the Pole and obtains

    only small values in the whole Polar Basin, for which reason the tides orig–

    inating in the Arctic Sea will be small and almost negligible. The observed

    semidiurnal tides, therefore, must be due to waves propagated from adjacent

    waters. Since Bering Strait is too narrow to be of importance, the tides

    from the North Pacific will not be perceptible except in the vicinity of Bering

    Strait and the semidiurnal tides in the Polar Sea must be closely related to

    the tides of the North Atlantic.

            The North Atlantic and the Polar Sea are in communication through Baffin

    Bay, through the wide opening between Greenland and Spitsbergen, and through

    the Barents Sea. The tidal wave which propagates through Baffin Bay will

    possibly control the tides in the Canadian Arctic Archipelago, but is not likely

    to be of much importance in the Polar Sea itself. The Barents Sea is shallow

    and almost cut off from the Polar Basin by the shallow banks which extend from

    Spitsbergen to Franz Josef Land and on to Novaya Zemlya. Furthermore the de–

    flecting force of the earth’s rotation tends to concentrate the tidal wave

    along the northern coast of Russia. The wave that passes between Novaya Zemlya

    and Franz Josef Land will, therefore, be unimportant, as is seen by comparing

    the tides at Cape Flora and Teplitz Bay. The tidal hours are 5.97 h. and 2.06 h.,

    respectively. The tidal hour at Cape Flora indicates that the tide at this

    place is connected with the branch of the tidal wave which passes across the

    Bar e nts Sea. This is seen if we compare the tidal hour at Cape Flora with the

    tidal hours at places in Novaya Zemlya, where at Byellushya Bay we find 5.74 h.

    and at Krestovaya Bay 5.53 h. The tidal wave at Teplitz Bay, on the other hand,

    003      |      Vol_VII-0615                                                                                                                  
    EA-Oc. Fjeldatad: Arctic Tides

    is evidently connected with the tide on the north coast of Spitsbergen.

            The deep and comparatively wide opening between Greenland and Spits–

    bergen is the chief communication between the Atlantic and the Polar Sea.

    It is, therefore, certain that the semidiurnal tide which is observed in

    the Polar Sea is almost entirely derived from the tidal wave which is

    propagated through this opening.

            The propagation of the semidiurnal tidal wave can be seen by a com–

    parison of the tidal hours at different places. The tidal hour means

    Greenwich time for high water of the component in question. It is found

    by dividing the phase angle X by 30 and adding the West Longitude of the

    place expressed in time. In Table 1 we have collected the tidal hours of

    the components M 2 and S 2 together with the phase difference S ° 2 - M ° 2 . The

    table is divided into four different sections. In the first part of the

    table we follow the increasing values of the tidal hours from the northern

    coast of Spitsbergen to Maud Harbour, Cape Chelyuskin. In the second part

    are represented the tidal data belonging to the Kara Sea branch of the tidal

    wave. The tidal hours seem to indicate that the tidal wave here comes from

    the north. The third part of the table shows the propagation of the Norden–

    skiöld (Laptev) Sea branch of the tide to the Lena Delta.

    004      |      Vol_VII-0616                                                                                                                  
    EA-Oc. Fjeldstad: Arctic Tides

    Table 1
    Station M 2 M ° 2 S 2 S ° 2 THM 2 THS 2 S ° 2 -M ° 2
    Port Virgo 41.4 38° 14.3 70° 0.55 h. 1.6 h. 32°
    Mosel Bay 35.0 87 13.1 121 1.82 3.0 34
    Treurenberg Bay 28.0 99 10.7 150 2.16 4.9 51
    Sveanor 25.1 92 11.1 138 1.85 3.4 46
    Brandy Bay 28.0 83 10.0 135 1.47 3.2 52
    Teplitz Bay 15.5 178 6.4 229 2.06 3.8 51
    Maud Harbor 12.6 324 5.0 3 3.76 4.1 39
    Zarya Harbor 17.7 26 8.2 99 6.53 9.0 63
    Port Dickson 8.55
    Nerpalakh Lagoon 7.3 25 4.6 91 3.90 5.9 66
    Sagastyr 9.30
    Bykhov 7.1 316 4.2 14 1.90 3.9 58
    Tiksi Bay 11.8 15 8.9 65 3.90 5.6 50
    Dashka Island 3.0 55 2.1 102 5.30 6.8 47
    Bennett Island 35.0 137 6.61
    Flaxman Island 6.7 354 2.7 37 9.53 11.6 43
    Point Barrow 5.2 336 2.1 16 9.65 11.0 40
    Aion Island 1.7 347 0.9 35 0.33 2.0 48
    Four Pillar Island 1.0 60 0.5 110 3.17 4.8 50
    Pitlekai 2.5 184 1.0 240 5.71 7.6 56
    Cape Serdtse Kamen 3.9 221 1.5 307 7.81 9.7 77

    005      |      Vol_VII-0617                                                                                                                  
    EA-Oc. Fjeldstad: Arctic Tides

            In the last part of the table we follow the increasing values of the tidal

    hour from Bennett Island to the northern coast of Alaska and across the

    Siberian shelf to Aion Island and Four Pillar Island. We see that the wave

    is propagated very rapidly across the deep Polar Basin from Spitsbergen to

    Cape Chelyuskin so that the time interval between high water at Port Virgo

    and Maud Harbor is 3.2 hours. The distance between the two places is 1,965 km.,

    giving an average velocity of propagation of 165 meters per sec. If we

    compare this with the simple formula c = √(gh) we find that the velocity cor–

    responds to a mean depth of 2,770 m. In reality the depths must exceed 3,000 m.

    Such depths were also found by Nansen.

            The difference between the tidal [ ?] hours of Port Virgo and Point Barrow

    is 9 hours. This is more than we should expect, for the distance between Port

    Virgo and Point Barrow is about 3,200 km., and the time of propagation would

    be only 6 hours if the wave were propagated across an uninterrupted deep polar

    basin with a depth of about 3,000 m. This point was one of Rollin A. Harris’

    strongest arguments for the assumption of a large tract of land in the Polar Sea.

            The time difference between Port Virgo and Aion Island is 11.8 hours. At

    Four Pillar Island high water takes place 2.8 hours later than at Aion Island.

    These tidal hours are best explained if we assume that the tidal wave is

    propagated across the shelf in a southwesterly direction.

            On the other side of the polar basin along the Canadian Arctic Archipelago

    few observations of the tide have been made.

            From the northern coast of Greenland and Grant Land we have some observa–

    tions made by Peary’s expedition. The tidal hours vary, with apparent ir–

    regularity, probably indicating the influence of the tidal wave from Baffin Bay

    006      |      Vol_VII-0618                                                                                                                  
    EA-Oc. Fjeldstad: Arctic Tides

    through Kane Basin and Robeson Channel. The two stations lying farthest away

    from the entrance to Robeson Channel are Cape Morris Jesup, on the northern

    coast of Greenland, with the tidal hour 0.68 h., and Cape Aldrich, on Grant

    Land, with the tidal hour 0.31 h.

            The Canadian Arctic Expedition under the leadership of V. Stefansson, 1913-1918,

    observed the tide at several points along the coast of the continent eastward

    frost Alaska to Amundsen Gulf, and also on the open shores of the Polar Sea on

    Banks Island and in the vicinity of Ellef Ringnes Island (3). The results are:

    Collinson Point: spring range, 0.60 ft.; neap range, 0.20 ft.; establishment

    of port, 0 h.18 m.. Demarcation Point: spring range, 0.72 ft.; establishment,

    12 h.14 m.. The tidal hours are 9.95 h. and 9.23 h., respectively. The ob–

    ervations at Cape Kellett gave as results: spring range, 0.43 ft.; neap range,

    0.40 ft.. The establishment could be determined only approximately and the

    result was 9 h.50 m.. If this be correct, the tidal hour is 5.63 h.

            The propagation of the tide on that part of the Siberian shelf to the

    north of the New Siberian Islands can be followed by the results of the hourly

    soundings. In Table 2 we have arranged the results according to increasing

    values of east longitude.

    Table 2
    Lat. M 2 M ° 2 TH Remarks
    I 76°39 139°40 50 cm 31° 3.7h July 23-25, 1924
    II 76 16 142 15 51 58 4.4 July 12-16, 1942
    III 75 46 143 25 (55) - (5.0) Fade e vski Isl. Aug. 13, 1924
    IV 76 30 143 58 49.7 89 5.4 July 2-3, 1924
    V 76 18 144 08 72 95 5.6 July 6-8, 1924
    VI 76 41 149 05 35 137 6.61 Bennett Isl., 1881
    VII 74 40 166 29 11 159 6.2 May 1-2, 1923
    VIII 74 26 167 45 13 153 5.9 April 25-26, 1923

    007      |      Vol_VII-0619                                                                                                                  
    EA-Oc. Fjeldstad: Arctic Tides

            In this ta lb bl e are also included the results from Bennett Island and the result

    of an observation from Fadeevski Island, which serve as a check on the results

    of the hourly soundings. We remark that the results from station I, II, and IV

    agree completely in regard to the amplitudes, and that the result from Fadeevski

    Island also confirms these results, which give larger tidal ranges than those

    found elsewhere in the Polar Sea. Station V gives a still greater amplitude,

    but this may possibly be erroneous, and to some degree be a result of the

    ship’s motion above a sloping bottom.

            The table indicates that the tidal hours change rapidly in this region.

    This fact is easily explained when we take into account that the depth on

    this part of the shelf is only some 20 meters.

            The direction of propagation in this region is about S. 80° E., as indi–

    cated by the results of current measurements.

            In the region to the east of Bennett Island the direction of propagation

    is more southerly, and across the shelf the direction must be toward the south–


            In the East Siberian Sea the direction of propagation must also be toward

    the southwest. The tidal wave is here stron g ly affected by frictional resistance

    and the amplitude in reduced from 12 cm. at the edge of the shelf to about 2 cm.

    at Aion and only 1 cm. at Four Pillar Island. The time necessary to cover the

    distance across the shelf to Aion Island is 6 hours. The distance is about

    530 km. and so the velocity of propagation will be about 24 m. per sec..


    Diurnal tides

            In Table 3 we have compiled all the available harmonic constants relating

    to the components K 1 and O 1 in the arctic regions. In the first column of the

    008      |      Vol_VII-0620                                                                                                                  
    EA-Oc. Fjeldstad: Arctic Tides

    table is given the western longitude of the station expressed in time. The

    first part of the table gives the harmonic constants for places along the

    eastern side from the northern part of Norway, Svalbard, and Siberia to

    Alaska. The other part of the table gives the harmonic constants for some

    places along the coast of Greenland and Grant land.

    Table 3
    Station Long. K 1 K ° 1 0 1 0 ° 1 THK 1 THO 1
    Bodø 23.04 10.3 208° 3.9 32° 12.91 h. 1.17 h.
    Kabelvåg 23.03 10.5 212 3.9 54 13.16 2.63
    Bear Island 22.72 5.4 230 4.4 66 14.05 3.12
    Port Virgo 23.29 2.7 225 1.2 12 13.62 0.08
    Mosel Bay 22.93 7.0 245 2.7 72 15.26 3.73
    Treurenberg Bay 22.88 7.3 270 2.1 70 16.88 3.43
    Sveanor 22.78 8.7 271 1.2 78 16.85 3.98
    Teplitz Bay 20.14 3.0 26 1.2 49 21.85 23.42
    Zarya Harbor 17.66 3.6 3 2.4 8 17.86 18.19
    Maud Harbor 16.97 4.8 24 2.0 4 18.16 17.25
    Nerpalakh Lagoon 14.86 0.6 293 0.3 350 10.39 14.19
    Four Pillar Isl. 13.17 0.6 12 0.4 76 13.97 18.24
    Aion Island 12.81 0.4 355 0.4 12 12.48 13.61
    Pitlekai 11 . 57 1.5 53 1.2 63 15.10 15.79
    Cape Serdtse Kamen 11.44 1.5 77 1.3 64 16.57 15.70
    Point Barrow 10.44 1.5 347 1.5 20 9.55 11.76
    Flaxman Island 9.77 2.4 7 2.7 45 10.25 12.72

    009      |      Vol_VII-0621                                                                                                                  
    EA-Oc. Fjeldstad: Arctic Tides

    Station Long. K 1 1 0 1 1 THK 1 THO 1
    Jan Mayen 0.56 3.4 97 6.1 49 7.00 3.85
    Denmark Isl. 1.75 8.7 65 9.3 35 6.08 4.08
    Little Finsch Isl. 1.41 11.8 75 7.6 25 6.41 3.08
    Cape M. Jesup 2.24 7.6 340 5.7 312 0.93 23.03
    Cape Bryant 3.70 9.8 286 4.3 262 22.77 21.15
    C. Sheridan 4.08 4.9 298 2.7 278 23.95 22.63
    Polaris Bay 4.12 12.2 246 4.6 209 20.51 18.04
    Fort Conger 4.32 8.5 222 5.8 199 19.12 17.59
    Cape Aldrich 4.67 5.2 311 3.4 281 1.36 23.36

            If we fix our attention on the component 0 1 we see that the phase is

    everywhere less than 90° for the stations along the coast from Alaska to

    Svalbard. The tidal hour increases from about 12 hours at Point Barrow to

    18 hours at Maud Harbor, and 23.5 hours at Teplitz Bay. [Pitlekai and Cape

    Serdts Kamen are situated near Bering Strait, and the tide here is possibly

    influenced by the tidal wave entering the Polar Basin from the North Pacific.

    These places are, therefore, not taken into account in the following discussion.]

            The difference of approximately 12 hours between the tidal hours of Point

    Barrow and Svalbard indicates that the wave is mainly generated in the Polar

    Basin itself and that it is a somewhat retarded equilibrium tide. In a circum–

    polar basin like the Arctic Sea the ideal tidal hours will differ little from

    the western longitude of the place expressed in time. From the table we see

    010      |      Vol_VII-0622                                                                                                                  
    EA-Oc. Fjeldstad: Arctic Tides

    that the tidal hours and the longitude run nearly parallel for 0 1 .

            The great value of the phase angle 76° which we find at Four Pillar

    Island is explained by the location of the island. The sea here is very shal–

    low and, owing to frictional resistance to the currents, the wave will probably

    b e of a progressive character across the shelf. The difference between the

    tidal hours at Aion Island and Four Pillar Island is too great, but we have

    to bear in mind that the tide here has a very swell amplitude so that the

    results are probably affected by relatively large erro r s.

            The tidal hour for the stations on the northern coast of Greenland and

    Grant land show the influence of the tide wave from Baffin Bay, which enters

    the Polar Basin through Kane Basin and Robeson Channel.

            For the component K 1 the tidal hour and the longitude correspond fairly

    well along the coast from Point Harrow to Teplitz Bay, but from there to Port

    Virgo we again find decreasing values of the tidal hour. Thus we find for

    Treurenberg Bay 16.88, Mosel Bay 15.26 and Port Virgo 13.62.

            These tidal hours are closely connected with the tidal hours in the Nor–

    wegian Sea. The diurnal wave K 1 enters the Norwegian Sea through the passage

    between Scotland and Iceland, and another branch enters through Denmark Strait

    between Iceland and Greenland. The observations are too few to trace the

    propagation of these two waves in detail, but the principal progress of the

    waves can be seen. The tidal hour for K 1 at Thorshavn, Faroe Islands, is

    9.5 h., at Bergen we find 10.98 h., at Bodø 12.90 h., and Port Virgo 13.62

    hours, These figures indicate that the wave is mainly of a progressive char–

    acter. The other branch of the wave may be traced at Denmark Island, Little

    Finsch Island, and Jan Mayen, where the tidal hours are 6.08, 6.41, and 7.00,


    011      |      Vol_VII-0623                                                                                                                  
    EA-Oc. Fjeldstad: Arctic Tides

            These two waves must Interfere in the strait between Svalbard and Green–

    land, and so the tidal hours at Port Virgo, and possibly also at Cape Morris

    Jesup, are influenced by this. The tidal hour at Cape Morris Jesup may also

    be influenced by the wave which enters through Robeson Channel.

            Tidal Currents.

            The shelf region north of Siberia presents unique conditions for the

    investigation of tidal currents. In the winter time the rigid ice cover is

    only slightly affected by the tidal motion, and there are no disturbances by

    surface waves. The Maud was in possession of a number of Ekman current meters,

    but these instruments were not well suited for use in the Arctic during the

    very low winter air temperatures. Dr. Sverdrup, with the assistance of the

    aviator, Odd Dahl, succeeded in constructing an electric registering current

    meter, which could be left in the sea for weeks at a time, and which regis–

    teredd the velocities and the direction of the currents on deck. This current

    meter was put in operation in the spring of 1923, and during spring and summer

    they obtained several long series of current measurements from a fixed depth.

            The hydrographic conditions on this part of the shelf are characterized

    by nearly homogenous water from the surface down to a depth of same 30 meters.

    Then comes a transition layer with rapidly increasing densities, and a bottom

    layer with more homogeneous water. The frictional resistance caused by the

    ice cover reduces the velocities in the upper layer, so that the greatest

    current velocities ordinarily are found in the transition layer. Near the

    bottom the velocities are again reduced by frictional influence.

            The current meter was operated in depths where from experience the greatest

    velocities were to be expected.

    012      |      Vol_VII-0624                                                                                                                  
    EA-Oc. Fjeldstad: Arctic Tides

            In Table 4 we give the results of some of the measurements during the

    spring and summer 1923.

    Table 4
    Series Lat. N. Long. E. V 1 V 2 T X TH
    1 74°12′ 168°50′ 16.4 −14.8 260° −75° 9.4
    2 74 20 168 33 14.6 −13.0 243 −83 8.9
    3 74 24 168 12 9.9 −8.0 241 −66 8.8
    4 74 40 166 24 18.6 −14.3 236 −94 8.8
    5 75 24 166 00 8.7 −8.3 243 −78 9.0

            In this table, V 1 is the maximum velocity and V 2 the minimum velocity of

    the component M 2 . T is the phase angle and X the direction of the maximum

    current. (−75° means S. 75° W.)

            The results are naturally affected by relatively large errors with respect

    to the angles T and X since the current ellipses are nearly circular.

            At spring tide the velocities reach values of some 30 cm./sec.

            In the summer of 1924 the Maud vas drifting with the ice along that part

    of the shelf which lies to the north of the Hew Siberian Islands. Here the

    tidal currents are considerably stronger and are able to break up the ice into

    smaller ice floes which to some degree are carried along with the tidal cur–

    rents. Measurements of the ice drift indicated the existence of tidal currents

    which sometimes amount to more than 40 cm./sec.

            The current measurements which were made during the summer of 1924 were

    combined with measurements of the ice drift, and thus it was possible to find

    the distribution of the velocities with depth.

    013      |      Vol_VII-0625                                                                                                                  
    EA-Qc. Fjeldstad: Arctic Tides

            We give here the results of three such series of current measurements

    (Table 5). On June 30, 1924, at longitude 143°53′ E., latitude 76°34′ N.,

    the depth of the sea was 36 meters and the Ekman current meter was working

    at depths of 15, 23, and 31 meters. The measurements were continued during

    one tidal period. It is seen that the velocities show a decrease toward the

    bottom, indicating the influence of friction.

    Table 5
    Depth V 1 V 2 T X TH
    0 17.2 −8.8 53° −6° 4.2
    15 14.4 −9.0 42 −23 3.8
    23 14.5 −7.2 71 31 4.8
    31 10.1 −0.2 72 44 4.8

            Observations made on July 23, 1924, at longitude 139°40′ E., latitude

    76°39′ W., provide one of the few instances when the surface drift of the ice

    and the surface elevation have been determined simultaneously. Thus it is

    possible to obtain a comparison between the observed amplitude and the ampli–

    tude which can be computed theoretically from the observed velocity.

    Table 6
    Depth V 1 V 2
    0 26.5 −15.9 −5° −29°
    12 24.1 −14.2 −7 −27
    20 14.3 −8.1 −12 −22

    014      |      Vol_VII-0626                                                                                                                  
    EA-Oc. Fjeldstad: Arctic Tides

            The computed velocities agree fairly well with the observed values.

    The computed angles can not be directly compared with the observed values,

    since the angle in the theoretical solution is reckoned from the time of

    high water, and the orientation of the current ellipse is reckoned from the

    direction of propagation of the tidal wave.

            The influence of the stratification of the sea on the tidal currents

    is demonstrated by a series of current measurements in the region to the

    east of Bennett Island in May 1923. The current meter was shifted at sev–

    eral depths and the currents thus determined. It was found that the

    velocities were strong at a depth of 40 meters, but decreased rapidly toward

    the surface and toward the bottom.

            Sverdrup explained this distribution of velocity by assuming that the

    eddy viscosity was great in the upper layer, where the water was homogeneous,

    and also in the bottom layer, but that the viscosity nearly vanished in the

    transition layer, where the stability is great. But the stratification is

    also favorable for the formation of internal waves, which might to some degree

    be responsible for the velocity distribution. The conditions for studying

    the dynamics of tidal waves and currents are very favorable in the shelf

    region of the Arctic, and one might wish that new arctic expeditions would

    take up such investigations.


    Jonas Ekman Fjeldstad

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