How far north can we see solar glint in GOES satellite tv for pc imagery?

By Bernie Connell and Erin Sanders

Solar glint is an optical phenomenon that may be seen in seen and near-IR satellite tv for pc imagery over water options akin to ocean, lakes, and rivers.  Its presence depends upon the geometry between Solar, Earth, and satellite tv for pc viewing angle.  When daylight is mirrored off water options in direction of the satellite tv for pc sensor at practically equal angles, one of these reflection is known as specular reflection.

How far north can we see solar glint? Solar glint is a typical incidence within the tropics and is often seen in daytime satellite tv for pc imagery between 30ºN and 30ºS.  The next examples present solar glint at latitudes increased than 30ºN throughout northern hemisphere summer time utilizing seen imagery within the purple a part of the spectrum (0.64 μm).  The primary animation exhibits imagery from the GOES-17 satellite tv for pc situated at 137.2°W within the early hours between sundown and dawn on July 21, 2021.  From this angle, a seasoned eye might discern the sample of solar glint areas showing to journey north and eastward with the altering angle of the solar.

GOES 17 – Arctic sundown and dawn on July 21, 2021 from 8:30-10:30 UTC.

Let’s zoom in on a couple of of those areas and take a more in-depth look.  From this angle the areas of solar glint are simpler to identify.  Because the Solar, water floor, and satellite tv for pc geometry modifications, areas of brightness seem after which disappear in lower than an hour.

GOES 17 – Arctic sundown on July 21, 2021 from 8:10-9:20 UTC.

These areas of solar glint point out comparatively calm waters with a easy floor to replicate daylight, very similar to a mirror.  The rise in mirrored photo voltaic power that reaches the satellite tv for pc sensor can saturate the picture as seen by the brilliant white swaths.  Nonetheless, not all water surfaces replicate daylight equally.  Winds trigger rougher water and waves that may scatter daylight in a number of instructions and seem darker, as much less daylight shall be directed to the satellite tv for pc sensor.  Cloud cowl may also obscure any water floor beneath.  Each of those can result in patchy areas of solar glint in satellite tv for pc imagery.  Are you able to differentiate between calm water, tough water, and cloud cowl within the subsequent two examples?

GOES 17 – Arctic dawn on July 21, 2021 from 9:00-9:50 UTC.

GOES 17 – Arctic dawn on July 21, 2021 from 9:20-10:20 UTC.

The next set of animations present solar glint detected by GOES-16 situated at 75.2°W on July 26, 2021.  We’ll once more begin with the complete view from sundown to dawn, after which deal with two examples.

GOES 16 – Arctic sundown and dawn on July 26, 2021 from 3:30-6:30 UTC.

Zooming in over the Pacific Ocean off the western coast of the USA exhibits the distinction between the in depth vivid glint space and darker surrounding areas of cloud.  The solar glint could be seen effectively above 40ºN.

GOES 16 – Arctic sundown on July 26, 2021 from 3:30-4:20 UTC.

Solar glint highlights areas of calm water and might reveal particulars concerning the water floor and its reflective properties.  On this subsequent instance, it additionally exhibits the ocean-land boundary with Greenland to the north.  Solar glint seems on the water floor however not land, though land can actually affect wind patterns over the water floor and have an effect on how the sunshine is mirrored.

GOES 16 – Arctic dawn on July 26, 2021 from 4:40-5:30 UTC.

So how far north can we see solar glint in GOES satellite tv for pc imagery?  It’s clearly seen above 75ºN on this present day!  The latitudinal extent of the place solar glint could be seen has a seasonal dependence.  Within the northern hemisphere it may be noticed between the vernal equinox (~20 March) and the autumnal equinox (~22 September).  The summer time solstice (~20 June) is after we would anticipate solar glint to be seen the farthest north of the equator primarily based on the positioning of the Solar, Earth, and satellite tv for pc.

Discover the surprising.