Autumnal Equinox

The autumnal equinox occurs tomorrow, the day that the Sun’s direct rays will be directly over the equator.  With North Dakota situated between 46 and 49 degrees north of the equator, this means that the shadows of an object are now longer than the object casting the shadow.  In addition, the amount of potential evaporation drops off quite rapidly this time of year.  It is also the reason that the water year begins on October 1 as this is a time of year that you tend to get more precipitation than evaporation in many parts of the northern hemisphere.  This is especially true in our area, but this is also the beginning of when we tend not to get much moisture to fall as well.

Daryl Rithcison

 

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