In my five and half months of living above 62 degrees north latitude I’ve learned many things regarding the effects that this location imposes upon daily life. Without question the meteorological effects are more extreme and definitely more pronounced but so are other aspects such as light. I recently experienced my first Winter Solstice above 62 degrees north latitude and it was definitely different from all those I experienced in the lower 48; the day was very short with not much light and a lot of darkness. Now in the lower 48 I remember seeing almost no perceptible shift in the daylight until we were well into February and I am a sky watcher and hence more aware of such nuances. However, up here, within two weeks I could definitely tell the daylight was increasing and that has continued to this writing. We are currently adding 3 minutes and 30 seconds of daylight per day and it is very noticeable. Yet this figure is the same regardless of where one is on the earth – okay, if you’re in the southern hemisphere then the daylight is decreasing but it’s still doing so by this same amount – so why is it so noticeable at higher latitudes yet becomes harder and harder to discern as one approaches the equator..?
My suspicion is it’s based upon the geometry of a sphere and one that’s tilted at roughly 23 degrees to the vertical in conjunction with the atmosphere. I’ve never been good with mathematics in general and geometry in particular but I can imagine the earth as a roughly spherical object (if ya want to get picky I guess it’s closer to an egg shape…) tilted 23 degrees off the vertical axis and not just spinning but also orbiting the sun. It’s the tilt that gives the earth its seasons; as it orbits the sun one of the two hemispheres (northern or southern) will at one point be closer to the sun – and hence have ‘summer’ – and at the opposite position in its orbit be tilted away from the sun and hence experience ‘winter’. So far, so good… Now, its known that the thickness of the atmosphere varies with location; it is thickest at the equator and slowly decreases as one moves towards the poles This means that sunlight reaching the earth has to travel through different thicknesses of atmosphere to reach the surface. The more atmosphere the light travels through the more diffuse it becomes; its scattered by all the various molecules in the atmosphere. Therefore at lower latitudes incoming light travels through more atmosphere and is more scattered and hence more diffuse and so would appear to be ‘weaker’ than light striking the higher latitudes. This could well account for the perceived slower shift to increasing daylight in the lower 48 as to up here; the more diffuse and ‘weaker’ light requires more time to finally begin to show a change where as in the higher latitudes the light is not scattered and diffused as much so smaller changes are more easily perceived by our eyes. This also explains that phenomena of ‘flat light’ that photographers often speak to; it’s this same sharper, stronger light that traveled through less atmosphere.
Or at least this all sounds well and good; an interesting test would be to find a planet with the same tilt but no atmosphere to use as a baseline. If this summation is correct the perceived increase/decrease of light on the planet without an atmosphere would appear to be the same regardless of one’s latitude. It’s these kinds of situations I enjoy investigating; to me they are not immediately obvious yet they are undeniable. Without question the less thick atmosphere produces some other effects at the higher latitudes; I suspect this is the reason I see such amazing barometric pressure swings up here. Just this past Monday I saw a pressure reading of 28.88″ Hg (978.26 Mb) which is extremely low and would be something one might see in the eye of a medium strength hurricane in the lower 48 yet up here it was just low pressure; we did see a bit of snow along with it but no winds or other extreme weather.
It’s an interesting experience living in the higher latitudes; it makes me wonder what it would be like living at 80 degrees north latitude if not higher..? I suspect I’ll never know as the farthest north piece of Alaska is around 71.5 degrees north latitude. Still and all its fun to wonder…
Anyone with even a modicum of understanding regarding the geometry of our planet with respect to our star knows that we see our seasonal procession based upon the tilt of the earth in relation to the sun. Given our planet is roughly spherical and the fact that we are inclined around 15 degrees its also no surprise that both seasonal differences and the amount of light and dark variation are much less at the equator and increases incrementally the further one moves towards the poles. Virtually everyone knows the far northern sections of Scandinavian countries such as Norway, Sweden and Finland are referred to as lands ‘of the Midnight Sun’ but this could be said of almost any country with land that is beyond 60 degrees north or south latitude. Of course there is the fabled ‘other side of the coin’ regarding these long periods of daylight and the northern hemisphere is now well on its way into such a period.
I knew I’d see much larger extremes in terms of both light and darkness as the seasons progress living at 62.27 degrees north latitude; for determining the extent of these values the internet is indeed a most useful tool. Even with my own research and exposure to the long periods of daylight during a couple of spring Alaskan trips back in the early 2000’s I’m finding I’m still both startled and impressed with the rapidity with which these changes take effect. This morning it was not even light enough outside to see the trees in my yard until 08:36 AKDT! Sure, its overcast – of late all I can say is ‘what else is new..?’ – and that does block the light to some extent but even as I type this at 09:17 AKDT I can look to the east and not yet see the light spot created by the sun as it crosses the horizon. Talkeetna is now seeing just 9.2 hours of daylight but perhaps the fact that just impresses me no end is we continue to lose 5 minutes and 37 seconds of daylight every twenty four hours!! Good grief, that’s 39.432 minutes of light loss per week..! As a point of reference here’s a few other US cities:
- Albuquerque, NM (ABQ) – currently 11.0 hours of daylight
- Atlanta, GA (ATL) – currently 11.1 hours of daylight
- Bellingham, WA (BLI) – currently 10.4 hours of daylight
- Colorado Springs, CO (COS) – currently 10.9 hours of daylight
- Kalamazoo, MI (AZO) – currently 10.7 hours of daylight
- Miami, FL (MIA) – currently 11.3 hours of daylight
To really grasp just how quickly the light is disappearing up here as of October 21st there is just a 2.1 hour spread between Miami and Talkeetna with just 15 days left until we reach the mid-point between the Autumnal Equinox and the Winter Solstice. Now look at how much daylight these same cities can expect on the Winter Solstice which as a matter of convenience I’ve stated as December 21st:
- Albuquerque, NM (ABQ) – 9.6 hours of daylight
- Atlanta, GA (ATL) – 9.8 hours of daylight
- Bellingham, WA (BLI) – 8.0 hours of daylight
- Colorado Springs, CO (COS) – 9.3 hours of daylight
- Kalamazoo, MI (AZO) – 8.9 hours of daylight
- Miami, FL (MIA) – 10.4 hours of daylight
- Talkeetna, AK (TKA) – 4.6 hours of daylight
In the span of just 66 days the difference in daylight between Miami and Talkeetna will jump to 5.8 hours! That’s almost a 300% increase in the difference in daylight in just a bit more than two months time.
The one question I heard more than any other when I would share my dream of living in Alaska was; “How will stand all that winter darkness?”. While I’d be the last one to try to convince anyone that I’m ‘mainstream’ in my beliefs and outlooks I have discovered that my feelings regarding this question directly matches what I hear from my fellow ‘Talkeetna-ites’ and probably most Alaskans; I know I’m gonna have much more trouble with the extended daylight than the darkness! I did experience this during the previously mentioned camping trips and it drove me nuts; its darn difficult to sleep in a tent when the sun is just setting behind Mt Iliamna in the Aleutian Range at 01:00 AKDT! When I first arrived up here on August 6th it was twilight until almost midnight and it was getting light at 05:00 AKDT; I had a very tough time until I purchased light blocking drapes for my bedroom windows.
Speaking of light I’m just now seeing the sun behind the clouds clearing the eastern horizon and its 09:37 AKDT. I do know many folks who hunger after sunshine and could easily live with 365 sunny days a year; I’m definitely not in this category! I need variety in my weather and I enjoy extremes as well. I will sorely miss the severe thunderstorms of the lower 48 along with the tornadic interludes and even the freezing rain (that doesn’t occur up here…); if there’s any solace for me its I will finally get to see snowstorms which regularly dump double digits of snow and bone chilling Arctic air outbreaks which will plunge air temps into the -15 F to -40 F range. Some folks suggested maybe my being ‘okay’ with so much darkness is a reflection of my soul; not in an evil sense but rather in a melancholy or sad sense. I suppose this is possible but I don’t think so; just as there are people as I mentioned earlier who live for sunshine and cannot tolerate even a couple of consecutive days of rain I favor first very variable weather but I’ll also generally take clouds over a clear sky. I’m sure growing up in SE Michigan fostered this perspective as winters there are usually overcast; in addition there’s no doubt I’m built for cold and hence extended sunlight is often too warm for me.
Although I’ve never experienced an Alaskan winter I’m sure I will be fine with the absence of light and the extreme weather conditions. I had darn well better be because my German Shepherd Dog (Qanuk) will not abide more than two consecutive days without at least an hour’s worth of walking (actually he runs everywhere, I walk..!). I’m in the process of trying to get an educated opinion regarding just how much cold he can endure for how long. I can see us walking outdoors in three feet of snow – yes, even though we have dirt roads for the most part they are plowed although some times it takes many days if the recent snow storm was particularly heavy – and an air temp of -30 F. I have made sure I have the gear required to handle these conditions and I know my Alaskan Malamute (Anana) will just love such weather; I just need to find out how long is safe for Qanuk to be out and about in such conditions. I would love to see the snow begin soon although given the recent weather pattern it could well be another few weeks; at least I know I will not be forced to endure what I came to refer to as a ‘brown winter’ which had become very common in SE Michigan. Rain and 35 F air temps is not winter to me..!