About 10, icebergs are produced in this region every year. Bergs then cross to the west side of the bay, where they move south in the Baffin Island Current toward Labrador. At the northern end of Baffin Bay, in Melville Bay, lies an especially fertile iceberg-producing glacier front produced by the Humboldt Glacier , the largest glacier in the Northern Hemisphere. Some icebergs take only 8—15 months to move from Lancaster Sound to Davis Strait , but the total passage around Baffin Bay can take three years or more, owing to groundings and inhibited motion when icebergs are embedded in winter sea ice.
The number of bergs decreases linearly with latitude. This reduction is primarily due to melting and break-up or grounding followed by breakup. Surviving bergs will have lost at least 85 percent of their original mass. Much work has gone into modeling the patterns of iceberg drift, especially because of the need to divert icebergs away from oil rigs. An iceberg is affected by the frictional drag of the wind on its smooth surfaces skin friction drag and upon its protuberances form drag.
The Drift Latitudes, by Jamal Mahjoub | The Independent
Likewise, the drag of the current acts upon its immersed surfaces; however, the current changes direction with increasing depth, by means of an effect known as the Ekman spiral. This force is typically stronger on icebergs than on sea ice, because icebergs have a larger mass per unit of sea-surface area.
As a result, it is unusual for icebergs to move in the same direction as sea ice. Icebergs progress at about 3 percent of the wind speed. When an iceberg runs aground, it can plow a furrow several metres deep in the seabed that may extend for tens of kilometres. Iceberg scour marks have been known from the Labrador Sea and Grand Banks since the early s.
In the Arctic, many marks are found at depths of more than metres 1, feet , whereas the deepest known sill , or submerged ridge, within Greenland fjords is metres about feet deep. This unsolved anomaly suggests that icebergs were much deeper in the past or that sedimentation rates within the fjords are so slow that marks dating from periods of reduced sea level have not yet been filled in. It is also possible that an irregular berg can increase its draft by capsizing, though model studies suggest that the maximum gain is only a few percent.
Since not all iceberg-producing fjords have been adequately surveyed, another possibility is that Greenland fjords exist with entrances of greater depth. In addition, iceberg scour marks have been found on land. On King William Island in the Canadian Arctic, scour marks have been identified in locations where the island rose out of the sea—the result of a postglacial rebound after the weight of the Laurentide Ice Sheet was removed.
Furthermore, Canadian geologist Christopher Woodworth-Lynas has found evidence of iceberg scour marks in the satellite imagery of Mars. Scour marks are strong indicators of past water flow. Observations indicate that long furrows like plow marks are made when an iceberg is driven by sea ice, whereas a freely floating berg makes only a short scour mark or a single depression.
It is thought that these patterns are created when a tabular berg runs aground on a wide front and is then carried forward by tilting and plowing on successive tides. Grounded bergs have a deleterious effect on the ecosystem of the seabed, often scraping it clear of all life. Both icebergs and pack ice transport sediment in the form of pebbles, cobbles, boulders, finer material, and even plant and animal life thousands of kilometres from their source area.
Arctic icebergs often carry a top burden of dirt from the eroded sides of the valley down which the parent glacier ran, whereas both Arctic and Antarctic bergs carry stones and dirt on their underside. Stones are lifted from the glacier bed and later deposited out at sea as the berg melts. The presence of ice-rafted debris IRD in seabed-sediment cores is an indicator that icebergs, sea ice , or both have occurred at that location during a known time interval.
The age of the deposit is indicated by the depth in the sediment at which the debris is found. Noting the locations of ice-rafted debris is a very useful method of mapping the distribution of icebergs and thus the cold surface water occurring during glacial periods and at other times in the geologic past. The type of rock in the debris can also be used to identify the source region of the transporting iceberg. Caution must be used in such interpretation because, even in the modern era, icebergs can spread far beyond their normal limits under exceptional conditions. For instance, reports of icebergs off the coast of Norway in spring coincided with the most extreme advance ever recorded of East Greenland sea ice.
It is likely that the bergs were carried eastward along with the massive production and outflow of Arctic sea ice. In one chapter, the Bash-Buzuq, an irregular cavalry division of the Ottoman army, captures families sympathetic to the Mahdi. Juma, the captain of the Bash-Buzuq, is enraged when the prisoners turn out to be more insolent than fearful, and prepares a cruel and unusual punishment for two of them:.
When the men returned with wood, two large crosses were constructed, rough and uneven like two deformed trees in the middle of the sandy plain. The old man and the mute were nailed on by their hands and feet, their waists bound to the stakes with rope to carry some of their weight, so that the nails should not tear through their flesh.
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The women wailed and screamed, but Juma was unrelenting. Other forms of torture could have been imagined, but for these insurgents crucifixion is pointedly humiliating. The Ottomans would like to see themselves as the biblical Romans; but in persecuting a messiah-figure from their own faith, they have more in common with the Pharisees. Juma seems to have forgotten that the soldiers of the mightiest army in Sudan were, nominally at least, followers of Christ.
He wields a Christian symbol to degrade other Muslims, but its meaning turns on him and, like the Mahdi, eventually slips his grasp. The officer to whom he makes this remark is Captain Ellesworth, the character who represents the British viewpoint. There are occasions, however, when the signs are conducive to cultural understanding.
In The Carrier , a 17th-century astronomer called Rashid travels to Europe to look for an optical device that enlarges perspective. He is shipwrecked off the coast of Jutland, and saved from intolerant Danes by a fellow astronomer, who discovers only later the expertise of his dark-skinned servant.source
On the latitude drift of sunspot groups and solar rotation
The novel is pleased with its conceit of the universe as a gateway to the universal. These metaphors struggle for effect since they are not specific to either culture, while the telescope is a very familiar symbol of new vision. Yasin, the narrator of Travelling with Djinns , once again has an English mother and a Sudanese father. He has left his Danish wife and is taking their seven-year-old son, Leo, on a trip through Europe, during which he tries to explain his multiple heritage.
Six months in the life of a year-old is one-seventy-fourth — his time is more precious than mine. It is and he has abandoned his English wife and daughter in London and moved to Liverpool; during the First World War he had served in a U-boat patrolling these waters. In a local jazz club, he meets a West Indian singer with whom he falls in love and has another daughter. The novel is mainly set in the present day and split between the viewpoints of the two half-sisters. The three lives are linked by a shared unease about family history, how much our lives are defined by it, and how much we can construct for ourselves.
The Drift Latitudes uses physical structures to describe the immigrant mind. After separating from her French husband, Jade reshapes her home and her life.
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When the refugee dies on her building site, she discovers that a German V-2 rocket was once dug up from its foundations. These metaphors are too neatly aligned with their meanings. A woman may indeed decide to make alterations to her house after a separation, but the symbolism involved in hollowing out its insides and keeping the front intact is too obvious, as is the business of the German rocket and the German family history or the church overrun by every multicultural fad.
In Wings of Dust the use of a similar trope is more refined.
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