Welcome Spring!

March 20, 2013 Comments Off on Welcome Spring!

Happy Vernal Equinox one and all! We hit the Meteorological Spring on March 1, and we have now joined Astronomical Spring as of March 20, 2013 at 6:02 am. We haven’t quite reached the spring celebration point yet up here in Northern Minnesota, but truthfully were we really expecting it this early anyway?

I did not grow up in Minnesota, spending my formative years in the more temperate climates of Kansas and Southern Pennsylvania, so I hadn’t experienced Minnesota winters prior to moving here to attend college. I have now lived here more than anywhere else, and have learned to adjust my thinking a bit. Where I grew up, it was reasonable to expect things like crocuses, tulips and daffodils to be blooming by late March, or at least up and making headway. After a number of winters here in Minnesota, I realized that a) the Groundhog was not from Minnesota and February 2 always means 6 more weeks of winter regardless of what happens with shadows on that date, and b) the Vernal Equinox did not mean we were anywhere near what I would call spring.

For those of us who remember last March fondly because of early warm temperatures- though not for its lack of snow, normal has returned at least for this year. I ran into an interesting comparison between last March and this March via Facebook (Thanks D.C.!) and thought I would share it with you. We are considerably cooler this year than we were last year at this point. Take a look at this graphic from Climate Central. It tells an interesting story to be sure. We are definitely a little cooler than average this year, while we were much warmer than average last year for the first few weeks of March. Remember those incredibly early ice off dates last year? Anyone want to make predictions for this year?

However, there really is good news out there, since we have now passed the Vernal Equinox, there really is no choice even in Northern Minnesota, the days will get longer and the weather will get warmer! It has to because of the change in the angle of the sun’s rays hitting the earth. On the Equinox we are no matter where we live worldwide having approximately 12 hours of daylight and 12 hours of dark on March the 20th this year. We reached that point where the Path of the Ecliptic (the route that the sun and moon and planets consistently follow through the night sky year round) has intersected the Celestial Equator (that imaginary line in space that follows straight out from Earth’s equator into the night sky). In the graphic below the red line is the Celestial Equator, and the green one the Ecliptic. From this point on in the Northern Hemisphere the Earth will be tilted toward the sun until September and the Autumnal Equinox where the Earth’s tilt begins that switch back to the Southern Hemisphere tilted toward the sun.

Image from http://www.space.com/20307-spring-season-vernal-equinox.html

I always find the change in daylength fascinating. We live in a region of the world where our daylength changes through the year from not quite 9 hours of daylight at our shortest day to almost 16 hours of daylight at our longest. A change of daylength of about 7 hours. That seems like a lot to me, but it is nothing compared to what happens in the polar regions of the earth, who go from nearly total darkness 24 hours a day to nearly total daylight 24 hours a day in the course of a few days around the equinoxes. Having not experienced that type of shift, or even 24 hour daylight or darkness, it’s hard to wrap my head around that kind of change. But equally hard is the notion that in the regions around the equator, they essentially have no change at all through the year- its always about 12 hours of daylight and 12 hours of dark. Guess I need to put on my traveling shoes and check these extremes out!

The Vernal Equinox also gives us another semi-annual occurance, the sun rises and set precisely in the east and west. Great way to figure out exactly how your world is oriented, like which way your house really faces. Below is a graphic of the changes on the declination of the sun from the point where it is furthest to the south of east and west at 22 degees above the horizon on the Winter Solstice through the Vernal and Autumnal equinoxes at 45 degrees and dead on, to the Summer Solstice where the sun reaches its highest point above the horizon at about 69 degrees. Again that change seems extreme at a difference of 47 degrees. But travel further to the south or the north and things change rapidly. Those of us who live in the northern part of the state gain about 12 minutes more daylight by Summer Solstice than those living in the Twin Cities region of the state. One of those many perks of living up north!

If you have been reading my blogs you have no doubt figured out that I definitely have Spring Fever, and am ready to see the trend of more snow every few days the last couple of weeks to come to an end, and for the great melt to begin. It’s time for sap to flow in the maple trees! Here’s to rising sap whenever it comes, it is just exciting to know that it will come! Hang on and enjoy the change.

These updates are made possible by a generous donation from David and Rosemary Good.