Early sunrise in Greenland. Is the explanation of scientist attributing it to global warming wrong?

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The early sunrise could be an atmospheric effect. The atmosphere is essentially a gradient index lens. The important feature to remember about a gradient index system is that light bends toward the higher index. The physics is the same as a fiber optic, but the scale is a bit bigger. The refractive index of air is a function of the temperature and pressure, and composition. The refractive index decreases as air warms and also with increasing humidity. If there is a mass of warm, moist air (relative to prior years) near the ground over regions to the south the conditions are right for a mirage. The sunrise further south is seen because there is an inversion in the refractive index with low index near ground level and higher index at elevation. Further, the refractive index is wavelength dependent with higher refraction at shorter wavelengths. An over the horizon sunrise would appear green because the red end of the spectrum is not refracted enough and the blue end is of the spectrum is lost to Rayleigh scattering.

Edit: Rio, the refraction effect that I refer to is from water vapor that has not condensed into droplets. If the water droplets (in liquid or ice form) are present a diffraction effect (rainbow) is also possible. Although isostatic rebound is probably not the right answer, it is a good and constructive answer because your hypothesis is a known physical phenomenon and it is possible to test the hypothesis against the evidence to either accept or reject the hypothesis. Science destroys far more hypotheses than it accepts. My hypothesis can be tested by analyzing photographs of the phenomenon for an change in the spectral distribution of the sunlight....Show more

I have spent a lot of time in the mountains. The sunrise is about an hour later on the West face of the Rockies, like in Grand Junction, CO. The Rockies are a helluva lot taller than an ice sheet in the Artic circle, of this I am confident. Though not as wide as an ice sheet..

But I find it hard to believe that just suddenly, for the first time ever, the sunrise is two days early. According to you people, the ice sheet has been in continuous meltdown for 120 years. The sunrise would be creeping forward by minutes per year, not just two days out of the blue. The isostatic rebound would be the same thing, a slow process.

If the rafting ice over the ocean had been undermined by warmer currents, there would have been a tsunami to wash away Greenland, when the shelf collapsed. For that much ice to fall that rapidly...somebody, some satellite, some seismic meter, somewhere would have noticed a few thousand miles, and millions of tons, of ice just suddenly dropping a few hundred feet.

This story pegs my BS meter....Show more

It took a little effort to locate Illulissat in Google Earth, and you're right, there's hills and a fjord, and more hilly terrain before part of the icecap appears---like at least 50 miles away. As I said in my answer to the referenced question, there's a lot of imprecision about the point of observation. However, it is still possible to "notice" that the sun has come up early. Let's say that you're a native of Illulissat, and you're in the habit of going to a coffee shop, and the front of it is in perpetual darkness until, say, Jan 13. But this year it's lit up on Jan 11. It's possible to notice those kinds of things fairly unambiguously that doesn't depend on subjective interpretation. After all, it's these kinds of observations that led ancient people to erect monuments to mark off astronomical events of the year.

If there is really an solid icecap "horizon" responsible for determining when this event occurs for Ilulissat, and it's 50 miles away, then instead of about 30 feet of ice melted down being responsible for 2-days early appearance of the sun, there would have to be more in the order of 500 feet of ice melted down. A virtual collapse of the local icecap. While nothing concrete can really be said for this story without more details, I wouldn't discount natives of Ilulissat reporting an early sun. If they say it seems awfully early for the sun to appear, I would give them some credence, because, after all, they live there....Show more

Didn't have to do any research. Landmass can rebound, though I've forgotten the technical term. Nor did I bother to google llulissat, so I could be wrong.

Edit: Ok wrong direction, should have looked. d/dx is right about refraction and clouds offsetting the curvature. One exception the clouds should be high altitude for flatting.

But thanks for the link....Show more

Never take seriously an article that uses the phrase "sparking fears" in the headline....Show more