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| Mirage in Greenland |
While surfing the web for earth curvature mirage information (another story), I just happened to come across an interesting article that speaks of the mirage effect in the polar regions and it brought me back to my post below from last year on November 28, 2011 titled: "The Location of the Ships? Maybe."
There was a lot of discussion in the comments section of that post on how far one could possibly see across the ice. Russell Potter first mentioned refraction at the horizon. We all ended up concluding approximately 15 or 20 miles would be the maximum one could see anything across the ice. If this article has any merit (click here) - then one might be able to see much farther across in the high arctic region.
Although, in this article they are talking about seeing mountains at 200 miles. Wow, maybe Mount Everest.
Mountains are much larger than a ship of Franklin's era. But it does possibly allow for exceeding the 15 to 20 mile mark maybe to see a fuzzy dot apparition of a ship. I clearly remember seeing these mirages of far out glaciers out on Hudson Bay last spring, and did take pics. Will have to look for those. It was remarkable how high they shot up from the horizon, almost reminded me a little of the the northern lights (aurora borealis) that we see once in a while in northern Wisconsin.
Excerpts:
Under arctic mirage conditions, instances of atmospheric visibility extending 320 km (200 miles) have been reported. In 1937 and 1939, W.H. Hobbs documented several occasions during which objects were sighted at distances well in excess of those possible under normal viewing conditions. One significant arctic-mirage sighting occurred on May 24, 1909 when Commander Donald B. MacMillan observed and clearly recognized Capes Joseph Henry and Hekla in Grant Land from his position on Cape Washington on the north Greenland coast 320 km (200 miles) away.
(now we all know this story below, and I believe it's Croker btw, not Crocker ------ well, if you are a Franklinite....)
For example, in 1818, Sir John Ross observed and named the "Crocker Mountains" in the Canadian Arctic, which he estimated to be 50 km (30 miles) away from his position in Lancaster Sound and appeared to block his way to finding the Northwest Passage. No such physical landmark has ever been found to exist. Hobbs hypothesized that Ross had actually seen the snow capped heights of North Somerset Island looming up from their actual position 320 km (200 miles) distant.
Interestingly, in 1913 the aforementioned Captain MacMillan lead an expedition to locate Crocker Land and the Crocker Mountains. As the expedition approached Ross' coordinates for the mountains, MacMillan wrote: "There can be no doubt about it. Great heavens, what a land! Hills, valleys, snow-capped peaks extending through at least 120 degrees of the horizon." They pushed forward across the arctic ice for 50 km (30 miles) inland and found...NOTHING! Crocker Land and the Crocker Mountains had been mirages!
I have a question. The upper part of the Sommerset Island is not too high (the highest altitude is less than 500 m). So, even if you put these mountains up on the sky because the "mirage" effect, wouldn´t they be too small to be seen from such distance?.
ReplyDeleteThe nearest point of the Sommerset Island from the mouth of the Lancaster Sound is in fact more or less near (320km) to be seen from there, but the range of mountains are 135 km farther.
In the article is said that James Ross saw the Churchill mountains in the Antartica from a distance of 500 km but they are more than 3.000 m high.
The effect creates the sensation of closeness but don´t approach the things.
P.S.: A very interesting article for those who are uninitiated on the matter (navigation I mean)as me.