Where’s Winter?

Warning: heavy geek content.

Meteorological winter is here as of December 1 and the sun has almost reached its lowest point in the sky. Even though we’re nearly 4 million km closer to the sun than we were in June, the low angle in the sky and short daylight hours ensure a limited amount of heat. There is an El Niño event occurring this year; rainfall amounts are down and temperatures have been considerably above average so far. Because the way the earth accelerates at this point on its way around the sun we have reached our earliest sunset time of 4:41pm while mornings will continue to darken until the end of the month.

Looking south towards the location of the proposed dog park. At celestial noon (12:09pm), the sun was 23.8° above the horizon. On December 22nd, it will appear to be only 23° above the horizon and then begin to recover until June 21 when it will peak at 69.8°.

Not a trace of ice by the river.

As a result of the mild weather there are some plants that have not yet gone into dormancy and they are a probable indication of what global warming will bring to Toronto’s climate if temperatures continue to rise.

A dandelion in flower.

A wild rose has retained its leaves.

Moss feeds on an old tree stump.

Garlic mustard lurks in the undergrowth.

The downside of such mild weather is that in wooded areas, and especially if warming affects Canada’s boreal forest, leaves on the ground slowly decompose when in a normal winter they would be compressed by snow and their carbon content preserved. This decomposition releases carbon dioxide, reducing the natural carbon sink effect of the boreal forest.

On a lighter note, although it’s quite common in Toronto for winter to begin in earnest after Christmas, this winter there is a feeling that we may be getting off lightly.

After the last two winters, let’s hope so.

Tennis players enjoying a mild December in neighbouring Lions Park.

 

 

We’ve hit bottom (sunset times anyway). Caution: geek content.

This is the time of year when evenings are dark and there seems no end to the gloom. Never fear, our current sunset time of 4:41 p.m. is the earliest it can be – even though the Winter Solstice is more than two weeks away. In fact, by December 16th, the sun will begin to set later, continuing its trend until June.

At first I was astonished by this fact. It seemed to go against everything that I thought I knew about the Winter Solstice and the length of the daylight hours. On closer examination, there is a similar anomaly in the sunrise times which are progressively later until January 9th. OK then so what’s going on? The answer lies in the orbit of the earth and our current position. The earth doesn’t travel around the sun in a circle, in fact it’s an ellipse which is a kind of oval shape. Currently we are almost at our closest annual approach to the sun which occurs around the 3rd of January. We’re about 800,000 km closer at the moment than we will be in July. We’re also travelling faster because we’re rounding the corner at the near end of the ellipse. Because of this, it takes longer for the earth to rotate into position and the solar noon drifts later and later. In late October, solar noon is around 12:01 p.m.  while today, it’s happening at 12:09 p.m. and it will move to 12:32 p.m. by February. Because of this, our sunset and sunrise times are pushed later, hence the earliest sunsets occurring well before the solstice.

Sorry, I just had to have my moment of Geekiness.

For a better explanation try this link.