The fascination of the impact of sunlight

 This morning, over the space of a few minutes I was able to see the impact of sunlight on the frost covered roofs of the houses across the street. The temperature was 27 F or about -3 C, but the roofs in the sunlight began to lose their frost.

I began by noticing that the roof at an angle of 45 degrees on the distant house cleared of frost before the shallower angled roof of the house in the foreground. In the photo above, taken just a couple of minutes after I observed that difference, both house have roofs clear of frost that are in direct sunlight.

 In this photo, taken just eight minutes later more roofs are almost clear of frost on the far house, while for the near house that clearing is just beginning.

In this last photo only a shaded section of one of the roofs of the far house still have frost. In the foreground, the shaded shed roof, where the sunlight is just appearing, is beginning to lose its frost.

Its a fascinating progression to me.

Here comes the sun.

Today's Ottawa Citizen has an article about solar radiation on this, the shortest day in the year. In Ottawa the day's length is down to its lowest of the year at 8 hours, 42 minutes and 49 seconds, But tomorrow will have a longer day by a grand total of four seconds. And the day's will get incrementally longer after that.

Today's sun will reach a peak elevation of 21.2 degrees above the horizon, a huge contrast to its angle of inclination of 68 degrees at the summer solstice. And the current solar radiation at 550 watts per meter will increase to 1240 watts. Summer is a coming in!

 I find this article fascinating while Anne calls it boring. There is a second article, about the number of fender benders and pedestrian injuries caused by falls during the freezing rain storm of yesterday. I feel the  article about the return of sunlight is much more uplifting.