* GOES-17 images shown here are preliminary and non-operational *

A comparison of GOES-17 (soon to become GOES-West) and GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above) revealed a plume of lake effect clouds streaming south of Fort Peck Lake in northeastern Montana on 11 January 2019. As a cold front moved south-southwestward across the region (surface analyses), surface winds shifted to northerly at Glasgow KGGW which brought a flow of colder air across the still-unfrozen lake. Note that before sunrise the initial formation of the lake effect clouds could be seen on Shortwave Infrared imagery — and after sunrise, the feature appeared progressively warmer (shades of orange) on 3.9 µm images as the supercooled water droplets at the cloud top reflected increasing amounts of incoming solar radiation.

An Aqua MODIS Sea Surface Temperature product at 1942 UTC (below) showed that mid-lake water temperatures south of Glasgow were as warm as 36ºF (lighter shades of blue) — significantly warmer than Glasgow’s early morning surface air temperatures that were as cold as 17ºF at 14 UTC.

A comparison of the Sea Surface Temperature product with the corresponding Aqua MODIS Visible (0.65 µm), Near-Infrared “Snow/Ice” (1.61 µm), Shortwave Infrared (3.9 µm) and Infrared Window (11.0 µm) images at 1942 UTC (below) showed the lake effect cloud plume as well as a patch of snow cover northeast of the lake — snow absorbs radiation at the 1.61 µm wavelength, making it appear dark on the “Snow/Ice” image.

Terra and Aqua MODIS True Color and False Color Red-Green-Blue (RGB) images viewed using RealEarth (below) showed that parts of the Missouri River upstream (to the west of) of Fort Peck Lake — in the area of the UL Bend National Wildlife Refuge — were beginning to freeze (ice and snow appear as shades of cyan on the False Color RGB images).

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* GOES-17 images shown here are preliminary and non-operational *

GOES-17 “Red” Visible (0.64 µm) images (above) revealed the low-level circulation of an occluded Hurricane Force low (surface analyses) over the West Pacific Ocean on 09 January – 10 January 2019. This storm was forecast to produce wave heights up to 40-60 feet.

GOES-17 Low-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images (below) showed the circulation of the storm at higher altitudes.

Metop-A ASCAT surface scatterometer wind speeds were as high as 67 knots southwest of the storm center and 63 knots to the northeast (below).

A toggle between VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 — as viewed using RealEarth — is shown below.

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GOES-16 (GOES-East) Mid-level Water Vapor (6.9 µm) images (above) revealed the formation of a standing wave cloud along the Minnesota shoreline of Lake Superior on 08 January 2019. This cloud feature was formed by a vertically-propagating internal gravity wave that resulted from the interaction of strong post-frontal northwesterly flow with the topography of the shoreline — the terrain quickly drops from an elevation of about 2000 feet above sea level (over northeastern Minnesota) to about 600 feet above sea level (over Lake Superior) in a very short distance.

A northwest-to-southeast oriented cross section of RAP40 model fields along line segment B-B’ (below) showed a deep pocket of positive Omega (upward vertical motion, yellow to red colors) that corresponded to the cloud band along the Minnesota Lake Superior shoreline. Note that this Omega feature was vertically tilted in an “upshear” direction (toward the northwest), and extended upward to the 350-400 hPa pressure level. There was also an increasing upward component of the ageostrophic vertical circulation, which was likely the initial forcing mechanism leading to formation of the standing wave cloud seen on satellite imagery.

A comparison of Aqua MODIS Visible (0.65 µm), Near-Infrared “Cirrus” (1.37 µm), Shortwave Infrared (3.7 µm) and Infrared Window (11.0 µm) images at 1912 UTC (below) showed characteristics indicative of a cirrus cloud band composed of small ice crystals: a highly reflective signature at 1.37 µm, warm brightness temperatures (around -5ºC) at 3.7 µm and cold brightness temperatures (-40 to -43ºC) at 11.0 µm.

A sequence of NOAA-20 (at 1808 and 1949 UTC) Suomi NPP (at 1859 UTC) VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images (below) exhibited a similar warm 3.74 µm / cold 11.45 µm signature of the standing wave cloud.

The coldest wave cloud infrared brightness temperature values of -40 to -47ºC seen on MODIS and VIIRS imagery roughly corresponded altitudes of 6.6 to 7.3 km (21,600 to 23,900 feet) according to 12 UTC rawinsonde data from International Falls, Minnesota (below).

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A webapp that was developed to match images and hence learn about the ABI spectral bands. After navigating to the page, click and hold on an image, draw a line to the matching image. You can “right click” to open an image. Finally click on the yellow “check” box to verify your selections.

8 Spectral bands

One option is to match 8 of the total 16 ABI spectral bands.

16 Spectral bands

Another option is to match all 16 ABI spectral bands.

Matching Visible bands to ground-based photos

With this webapp, one matches the correct ABI visible spectral band with a photograph that was taken on the ground. A short (30-sec) animation on running the webapp: mp4 or mov.

How to use this webapp with your images

Check out this site for directions on how to build a web page to match pairs of images. This webapp is Copyright © 2018 by Tom Whittaker. Images from T. Schmit and NOAA. Inspired by Jordan Gerth’s ABI Matching game.

Questions and other Webapps

Webapps have been developed to demonstrate other concepts of remote sensing, such as pixel size and generating composites.

For any questions.

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