Tag Archives: Vernal Equinox

Climatology

Satellite imagery provides bird’s eye view of Earth at the change of seasons

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Satellite imagery provides bird’s eye view of Earth at the change of seasons.

Pretty neat imagery and explanation from NASA:

Enjoy the Equinox!

Every year, there are two equinoxes. One is in March; the other is in September. In 2014, the March equinox falls on March 20, 2014. On the equinoxes, the sun shines directly on the equator and the length of day and night is nearly equal. Seasons are opposite on either side of the equator, so the March equinox is called the spring (or vernal) equinox in the northern hemisphere. But in the southern hemisphere, it’s known as the fall (autumnal) equinox. What do equinoxes look like from space? The Spinning Enhanced Visible and Infrared Imager (SEVIRI) on EUMETSAT’s Meteosat-9 captured these four views of Earth from geosynchronous orbit. The images show how sunlight fell on the Earth on December 21, 2010 (upper left), and March 20 (upper right), June 21 (lower left), and September 20, 2011 (lower right). Each image was taken at 6:12 a.m. local time. Notice how on March 20 and September 20, the terminator — the divide between day and night — is a straight north-south line, and the Sun is said to sit directly above the equator. Equinox means “equal night” in Latin, capturing the idea that daytime and nighttime are equal lengths everywhere on the planet.

Read more about the equinoxes and solstices at
http://earthobservatory.nasa.gov/IOTD/view.php?id=52248&src=fb

See a video of the equinoxes and solstices from space at
http://www.youtube.com/watch?v=FmCJqykN2J0

Read more about the March Equinox from Date and Time at
http://www.timeanddate.com/calendar/march-equinox.html

Astronomy, Climatology

Image captures the start of spring as seen from space

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Spring officially began this morning at 5:02am MDT.  It is during this time, the vernal equinox, that the Earth’s axis is not tilted toward or away from the Sun.  As a result equal amounts of the Sun’s light are directed to the Northern and Southern Hemispheres.

Soon after the event this morning one of NOAA’s GOES satellites captured the light on the face of the planet in near perfect equilibrium.

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At 7:02 ET on March 20, 2013, Earth was at its equinox. At 7:45 ET, the GOES-13 satellite captured this full disk image of Earth. (NOAA) Click the image for a larger view.

From NOAA:

Mar 20, 2013
GOES Satellite Captures Spring Equinox
It is that time of year again (it happens twice) when the relative angle of Earth is perpendicular to the Sun, causing equal incoming solar energy to the Northern and Southern hemispheres – as well as equal day and nighttime. At 7:02 ET on March 20, 2013, Earth was at its equinox. At 7:45 ET, the GOES-13 satellite captured this full disk image of Earth. The visible imagery sensor on GOES requires sunlight to “see” clouds, and so it provides a useful example of the equinox. In this image the GOES imagery extends to each of the poles since the entire hemisphere is equally lit. After the equinox passes today, the Northern Hemisphere will be more lit than the Southern Hemisphere – causing the seasons. (Note: the Sun in this image is artificially created, though the GOES spacecraft does have sensors continually monitoring the Sun for solar activity.)