Where did the water originally evaporate when snow falls at the polar and Greenland ice caps?

I can think of two ideas:

  1. The water mostly evaporates from the nearest ice-free ocean because water vapour that evaporated further away falls as rain before it is transported to the poles
  2. The water vapour mostly evaporates in warm oceans nearer the equator and is transported by wind/jet streams high in the atmosphere

Which of these two ideas is more correct?

What proportion of snow falling at the ice caps originated from different latitudes? This might include water that evaporated from last year's snowfall.

How do we know, and are there some good studies?

Thank you

  • 2
    $\begingroup$ look up polar circulation cell, at around 60 degrees latitude the air is mostly rising pulling moisture from the surrounding area, and it sinks back down at the pole, that is why most of the polar precipitation is around 60 latitude, and the poles themselves are almost pure desert. Here is a place to get started. en.wikipedia.org/wiki/Atmospheric_circulation $\endgroup$
    – John
    Commented Apr 5 at 15:45
  • 1
    $\begingroup$ Thank you John, very helpful. ChatGPT came up with this: "The subtropical Atlantic is a major source of moisture for the Northern Hemisphere, including Greenland", but I want to check if this is accurate and what scientific studies back it up $\endgroup$
    – Peter A
    Commented Apr 5 at 19:43

1 Answer 1


We can get relatively warm waters much closer at hand to Greenland than tbe tropics, thanks to the Gulf Stream and North Atlantic Drift Current. It won't be Miami Beach, but the western coast of nearby "lceland" has an average ocean temperature of approximately 9°C source. This is enough to almost double the vapor pressure of water over what it would be at 0°C, so when winds are blowing from Iceland towards Greenland they will carry plenty of water that may be condensed as the temperature drops to below freezing.


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