Kane’s Mysterious Waters: Transient Polynyas

Open_Polar_Sea (1)

From “Arctic Exploration Grinnell Expedition 1853-1854-1855”, artist James Hamilton after sketches by Elisha Kent Kane, engraved by R. Hinshelwood.

Led by Elisha Kent Kane, M.D., the Second Grinnell Expedition (1853-1855) continued on-going searches for the missing Franklin Expedition. According to Kane’s writings in Arctic Explorations, his approach was to take a course that should “lead most directly to the open sea of which he had inferred the existence” and to “examine the [Greenland] coast-lines for vestiges of the lost party.” Within the first dozen or so pages of his book, Kane had established the theoretical existence of an open polar sea.

Kane further supports the existence of open seawater by referring to noted historical explorers:

An open sea near the Pole, or even an open Polar basin, has been a topic of theory for a long time, and has been shadowed forth to some extent by actual or supposed discoveries. As far back as the days of Barentz, in 1596, without referring to the earlier and more uncertain chronicles, was seen to the eastward of the northernmost cape of Novaia Zemlia; and, until its limited extent was defined by direct observation, it was assumed to be the sea itself.

The Dutch fisherman above and around Spitzbergen pushed their adventurous cruises through the ice into open spaces varying in size and form with the season and the winds; and Dr. Scoresby, a venerated authority, alludes to such vacancies in the floe as pointing in argument to a freedom of movement from the north, inducing open water in the neighborhood of the Pole. [1]

Kane also theorizes a milder climate towards the [North] Pole; however, he does not provide an explanation as to how such an open sea may exist:

It is impossible, in reviewing the facts which connect themselves with this discovery, — the melted snow upon the rocks, the crowds of marine birds, the limited, but still advancing vegetable life, the rise of the thermometer in the water, — not to be struck with their bearing on the question of a milder climate near the Pole. [2]

While discussing the northern extent of the search for Franklin, Kane provides the number of miles searched and approximate longitude and latitude coordinates of ice-free water:

During this period [August and September, 1854] the labours of the expedition have delineated 960 miles of [Greenland] coast-line, without developing any traces of the missing ships or the slightest information bearing upon their fate. The amount of travel to effect this exploration exceeded 2000 miles, all of which was upon foot or by the aid of dogs.

Greenland has been traced to its northern face, whence it is connected with the further north of the opposite coast by a great glacier. This coast has been charted as high as lat. 82° 27’. Smith’s Sound expands into a capacious bay: it has been surveyed throughout its entire extent. From its northern and eastern corner, in lat. 80° 10, long. 66°, a channel has been discovered and followed until further progress was checked by water free of ice. This channel trended nearly due north, and expanded into an apparently open sea, which abounded with birds and bears and marine life. [3]

Kane recorded these observations of open Arctic water north of Cape Andrew Jackson, and his findings were reportedly corroborated by Isaac I. Hayes, M.D., Hans Hendrik, and by notations in William’s Morton’s journal:

The journeys which I had made myself, and those of my different parties, had shown that an unbroken surface of the ice covered the entire sea to the east, west, and south. From the southernmost ice, seen by Dr. Hayes only a few weeks before, to the region of the mysterious water, was, as the crow flies, 106 miles. But for the unusual sight of birds and the unmistakable giving way of the ice beneath them, they would not have believed in the evidence of eyesight. Neither Hans nor Morton was prepared for it.

Landing on the cape, and continuing their exploration, new phenomena broke upon them. They were on the shores of a channel, so open that a frigate, or a fleet of frigates, might have sailed up it. The ice, already broken and decayed, formed a sort of horseshoe-shaped beach, against which the waves broke in surf. As they travelled north, this channel expanded into an iceless area; “for four or five small pieces” – lumps – were all that could be seen over the entire surface of its white-capped waters. Viewed from the cliffs, and taking 36 miles as the mean radius open to reliable survey, this sea had a justly-estimated extent of more than 4000 square miles. [4]

Note: Line-of-sight to a 36-mile water horizon requires the viewer to be ~650 feet above mean sea level.

Polynyas are semi-permanent open water greater than five square kilometers and are surrounded by sea ice. Generally, they are formed by two mechanisms: 1) upwelling warmer sea water melting surface ice, and 2) wind and wave-action breaking ice, particularly thinner first-year ice, that is then widely dispersed by wind and by water currents. These hydrodynamic forces in combination can potentially open vast areas of Arctic seas in summer and/or winter with year-to-year variations, forming polynyas that range in size 10 to 100 kilometers. [5,6]

The Canadian Arctic Archipelago has at least 23 documented polynyas and several shorelead polynyas, the latter of which can extend hundreds of kilometers. Of note, the North Water (NOW) polynya is one of the largest and most widely studied, occupying much of Smith Sound and extending north towards the southern entrance of Kane Basin. Smaller polynyas are present at Flagler Bay (Ellesmere Island), and at the confluence of Robeson Channel and the Lincoln Sea. Numerous smaller, transient polynyas can be found year round throughout the Arctic, and at times, along the Ellesmere-Greenland waterway. [7]

Kane alluded to the importance of polynyas to nearly all Arctic animals, especially marine mammals, when he observed that the open sea “abounded with birds and bears and marine life.” According to Martin, the NOW polynya “contains large concentrations of white whales, narwhals, walruses, and seals, with polar bears foraging along the coast… All of this suggests that polynyas are vital for the overwinter survival of arctic species. [8]

Because 19th century Arctic explorers lacked adequate instrumentation to study and measure Arctic polynyas, Kane and others theorizing them as an open sea is understandable, since their presence had been observed for hundreds of years by Arctic region fishermen and explorers. Kane, nonetheless, had identified one key element of polynya formation, comparatively warmer water (though without the upwelling component). Because these open areas of water were predictable along the Ellesmere-Greenland coastlines, Kane aptly utilized them as part of his overall strategy when searching for the lost Franklin Expedition. Research continues on the formation and oceanographic characteristics of Arctic and Antarctic transient polynyas.

Notes:

  1. Arctic Explorations in Search of Sir John Franklin, Elisha Kent Kane, M.D., U.S.N., T. Nelson and Sons, Paternoster Row, Edinburgh and New York, 1877, p. 182.
  2. Ibid, p. 183.
  3. Ibid, p. 206.
  4. Ibid, pp. 179-180.
  5. “Polynyas,” Seelye Martin, University of Washington, Department of Oceanography, 2001, p. 1-7.
  6. On Sea Ice, W. F. Weeks, University of Alaska Press, Fairbanks, Alaska, 2010, p. 281-329.
  7. “Polynyas and Tidal Currents in the Canadian Arctic Archipelago,” Charles G. Hannah, et al, Arctic, 62, 1, March, 2009, p. 83-95.
  8. Martin, p.4.

Frances Hennessey writes informally on Dr. Isaac Israel Hayes and other 19th century Arctic-related topics. Fran tweets @openpolarsea and has a poetry blog www.oceanic-visions.com

Understanding By Degrees: Determining Latitude (Part 1 of 3)

Posted by on Oct 28, 2013 in Arctic Visions, Navigation | 2 Comments
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Sextant, made by Jesse Ramsden, last quarter of 18th century, courtesy of the National Museum of American History, Smithsonian Institution. Diagram courtesy the English Wikipedia

Arctic explorers in the 19th century routinely used a sextant for celestial navigation to determine their location at sea and when trekking across glaciers and other terrain on foot or by dog sledge. This first of three posts discusses basic principles of obtaining solar-noon latitude by sextant and the inherent errors often present when attempting to sight the low-angled Arctic sun. Latitude findings enabled explorers to determine and document how far north they had traveled, and at times, to document historical most northern points explored in the High Arctic.

The Greeks developed the concept of latitude and longitude grids that systematically divided the earth into a system of horizontal lines of latitude (going east to west) that originated at the equator. One degree of latitude equals ~70 miles and is constant from the equator to the geographic North and South Poles. The equator represents zero degrees latitude.

The primary instrument used in celestial navigation, the sextant, refers to the Latin word for one-sixth of a circle or 60 degrees. It is designed to measure the relative angle between two items, typically the horizon and the sun, moon, and stars. In addition ascertaining the angle of the sun, an accurate celestial sighting required eye-height above the ocean and exact time.

Hovering over the southern horizon, the Arctic summer sun was the explorer’s constant companion. After the June solstice, from the Arctic Circle (N66º 34’ 44”) to the geographic North Pole, the sun provides 24 hours of light (ergo the “midnight sun”). For this reason, explorers relied upon sun sightings to ascertain latitude. At high latitudes, the sun can often appear as a hazy, opalescent disc rather than a distinct point of light. While this procedure appears straightforward, the High Arctic sun appears to circle (in a horizontal ellipse) over the southern horizon, making exact noon sightings taken under hazy skies often problematic.

The ship’s astronomer (or other trained crew) typically made daily noon-sun sightings and computations to confirm location, especially for off-ship explorations. Out of maritime tradition and practice, documenting explored locations was a routine requirement. Noteworthy events and locations visited were typically verified by accompanying team members (assistants) and officially recorded in ship logbooks and/or in personal diaries, providing a written record of daily crew activities, particularly meteorological and other scientific observations. During 19th century Arctic explorations, nothing of consequence aboard or off-ship was performed in isolation, aside from routine assigned duties, such as melting snow for water or stoking fires.

In general practice, instructions using a sextant have varied little over the past 150 years and are described in basic terms. To properly sight the sun, the sextant should be held vertically. A basic sighting tube is preferred since the sun is a relatively larger disc than the point of light of a star or planet.  With the index arm set at zero degrees, the horizon is sighted using the half-horizon mirror. Next, the index arm is carefully moved forward so that sun is visualized. Once the lower limb (or “edge”) of the sun touches the horizon, the degrees of latitude can be read at the graduated arc. At this point, the index arm should be clamped in place and the sun’s position minutely adjusted as needed with the micrometer or vernier dial. The window in the index arm provides the height of the sun above the horizon measured in degrees.

The eye-height of the observer (and thus the sextant) should be measured above sea level, to include the height of the ship’s deck. Typically, when standing on a flat ocean beach, light-of-sight is about 4.7 km (~3 miles) to water horizon. As observer height increases, so does the light-of-sight across a bay, sound, or the ocean. On modern sextants, several filters or shades reduce intense solar light to a visible disc. These filters were not present on pre-19th century sextants; thus, crew members who frequently made noon-day sun sightings potentially received repeated eye-blinding injuries. After obtaining the height of the sun (in degrees) at local solar noon, with the exact time (as possible), 19th century Arctic explorers used sight reduction tables found in American and/or British Almanacs for latitude (and longitude) calculations.

Prudent mariners and explorers of the era routinely verified calculated positions, especially those that appeared too far north or south of previously confirmed locations. Daily travels on foot or by boat were verified and tentatively confirmed by making calculations of distance, speed, and time. For example, computed distances of 70 miles (one degree of latitude) by foot or by dog sledge over broken sea ice and/or punishing ice hummocks would have been questioned by knowledgeable crew members and distances recalculated for accuracy.

Sextants of the 19th century were prone to inherent errors because of temperature extremes, mirror misalignment, and when other components, such as the spotting scope, may be potentially out of adjustment or collimation (optical-mechanical alignment). All of these potential errors can be further complicated by the extreme rigors of Arctic exploration, including the effects of cold and fatigue, while on dog sledges and/or trekking amongst tumultuous ice hummocks or unstable (“rotten”) ice. The environmental hazards experienced then are still arduous and potentially life-threatening to present-day Arctic explorers and mariners.

Frances Hennessey writes informally on 19th century Arctic exploration, concentrating on Hayes. Fran has a small collection of Hayes first editions, two of which are signed by the author. She also tweets @openpolarsea and has a poetry blog: www.oceanic-visions.com