Halloween Moon on GOES-13 imagery

October 31st, 2010

GOES-13 0.63 µm "visible channel" image

GOES-13 0.63 µm "visible channel" image

Steve Nazar wrote in an email:

“For the first time, I’ve seen Luna in a GOES photo! Maybe this is commonplace, but I’ve only seen it this once in roughly 20 years of looking at your site. Luna was in GOES East at 2345H Oct 31, and in no others in the sequence. It showed just above the horizon over Vancouver Island, in all wavelengths.”

The GOES-13 (GOES East) 0.63 µm “visible channel” image (above) did indeed show a crescent of the Moon being illuminated just off the Earth’s horizon late in the day on 31 October 2010. A wide band of cloudiness moving over much of British Columbia and the Pacific Northwest was associated with a frontal boundary and an upper level trough of low pressure over that region . As it turns out, the Moon can actually be seen on GOES images a handful of times every year, depending on the viewing angle of the satellite in relation to the position of the Moon (for example, see http://cimss.ssec.wisc.edu/goes/blog/archives/2106).

GOES-13 3.9 µm "shortwave IR channel" image

GOES-13 3.9 µm "shortwave IR channel" image

The GOES-13 3.9 µm “shortwave IR image (above) showed that the illuminated portion of the Moon exhibited very hot IR brightness temperatures (dark black enhancement) — the maximum value indicated using McIDAS was 340 K. The very hot sunlit surface of the moon can actually reach temperatures of 383 K / +110º C / +230º F, while surface temperatures on the very cold “dark” side of the moon can fall to 93 K / -180º C / -292º F.

GOES-13 6.5 µm "water vapor channel" image

GOES-13 6.5 µm "water vapor channel" image

The GOES-13 6.5 µm “water vapor channel” image (above) showed a rather interesting pattern of banded gradients — this was due to the fact that the water vapor channel detectors are designed to sample much colder features, so the extreme heat of the illuminated moon surface caused a supersaturation or “roll-over” from hot (black) to cold (white).

GOES-13 10.7 µm "IR window channel" image

GOES-13 10.7 µm "IR window channel" image

The GOES-13 10.7 µm “IR window channel” image (above) also displayed very hot IR brightness temperatures across the sunlit portion of the Moon (as high as 330.5 K).

An animation of these 4 images is shown below:

GOES-13 visible, shortwave IR, water vapor, and IR window channels

GOES-13 visible, shortwave IR, water vapor, and IR window channels

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