Solstice Solstice Solstice, Equinox Equinox Equinox

November 18, 2010

Today it was sunny for the first time since I got back to Bozeman. Sun is nice. Sun is one of my favorite things. If I were a mole and had to live underground, I would be very sad. If I was a wharf rat in a rainy place, I would be very sad. In fact, I moved to Bozeman because it is generally sunny here.

The problem was that it was very warm as well. It got into the 50’s.

The temperature and wind combined to make the snow a little slushy and a little non-existent at the beginning of the trail, but thank goodness for the temperature-elevation gradient, it was much improved, although a little sticky, as I climbed up Sourdough.

Sunlight generally means warmer temperatures, but in far northern and southern latitudes the sun in winter is at an oblique angle and instead of soaking into the ground, it bounces back into the hinterlands of the atmosphere forgetting to leave its warmth behind (especially when there is snow, which has a high albedo or reflection rate, not to be confused with libido, or sexual desire). However, judging by my inability to wake up before 7:00 am and my need to go to sleep at 5:00 pm, there is not a lot of sunlight blessing Bozeman these days. Why was it so warm today?

Okay, there are a lot of reasons why it was warm, but I want to investigate why it is warmer in November than in January when there is the same amount of sunlight. We are 32 days away from the solstice. The average temperature in Bozeman on November 18 is a high of 39 and a low of 16 (it was obviously warmer today, but this is just a nasty mean). The average temperature 32 days after the solstice on January 21 is a high of 30 and a low of 8, which is not as different as I thought it would be, but still below the all important 32 degrees.

Seasons lag behind solstices and equinoxes (Two of my favorite words, by the way. Say them three or four times and you will know why) because the earth and more importantly the oceans store heat energy. Water has a high latent heat, or amount of energy needed to change states. A lot of energy, in this case sunlight, needs to injected into the oceans to cause temperature change enough to affect global weather patterns. The same is true when less energy is heating the water. It takes a while for the energy (heat) in the water to be released.

So January is colder than December and July is warmer than June. We knew that already. But this lag time is important in understanding the global climate, which we all know is changing due to our greedy consumption of fossil fuels, which are far less tasty than Ben and Jerry’s Fossil Fuel ice cream. More carbon dioxide molecules in the hinterlands of the atmosphere are reflecting sunlight back toward the earth and this time it will leave a little more heat near the ground. Because of the lag time, we may not know when the oceans are too warm for the earth to continue on its seasonal cycle until there is no chance of reversing the trend.

Then January might be like November and November like September and there won’t be nearly enough time to ski…let alone survive.

The weather today made me remember how gorgeous Bozeman is. Check out the wind on top of Baldy. You can click the photo to make it larger.

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One Response to “Solstice Solstice Solstice, Equinox Equinox Equinox”

  1. Hannah said

    You said oblique. Cool.

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