Suomi-NPP VIIRS Visible (0.64 µm) images (above) showed a variety of Beaufort Sea ice floe motion within the nearshore waters of Alaska and Yukon during the 20-21 June 2022 period. Just north of Utqiavik (or Barrow, PABR), a sharp “shear line” was seen on 20 June — with a narrow line of ice flows moving east-northeastward, directly adjacent to the the pack ice that was moving westward.

Farther to the east (in the bottom right corner of this satellite scene), a fracture in the fast ice off the Yukon coastline led to the separation of a large ice floe on 21 June — which then drifted west-northwestward. Of note were the unusually warm surface air temperatures at stations near/along the northern coastline of Yukon, with some temperature readings rising into the upper 50s and low 60s F.

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Gridded NUCAPS data, available from NOAA-20 data within AWIPS, can be used to construct cross-sections in AWIPS. The image above includes an editable baseline J-J’ (one of 10 different lines that can be used for data in AWIPS) from Minnesota into Indiana, roughly perpendicular to a line of broken cumulus over Wisconsin and Iowa.

The cross section of equivalent potential temperature, above, shows very warm temperatures over the southern portions of the cross section, with theta-e values around 350 K. Potential Instability, i.e., theta-e values decreasing with height, is widespread along the cross-section. The broken cloud field in the VIIRS imagery on top eventually did initiate convection, as shown in this radar capture from 0012 UTC on 22 June.

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How do you create the cross-sections in AWIPS? Use the Volume Browser, as shown in the screen capture below. Select ‘Cross Section’ (vs. ‘Plan view’, for example) from the choices in the Volume Browser right next to ‘File’, ‘Edit’ and ‘Tools’, then choose ‘GriddedNUCAPS’ under ‘Sources’, and choose the correct Plane — as one of the Specified Lines you have previously moved in AWIPS; then choose the variable (possibilities are shown in the image; I chose Equiv Pot Temp).

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Imagery in this blog was created using a cloud instance of AWIPS from the TOWR-S group within NOAA/NWS. Thank you!

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The five-day composite of the VIIRS flood product is just one flood product that can be viewed in RealEarth. VIIRS is an instrument aboard SNPP and NOAA-20, which are low earth orbiting satellites. This means that while only two daytime observations may be retrieved per day over a given region, the spatial resolution of 375-m is quite highly resolved. VIIRS flood composites, such as the five-day composite, provide the “maximal flood extent” during flood events. More information about VIIRS and other satellite flood products can be found here.

In areas of Bangladesh and northwest India, persistent rains have caused recent heavy flooding. Millions of people have already been displaced and the flooding is forecast to continue. The VIIRS five-day flood product composite over a six-day time period can be seen below, with the 7-day CMORPH2 satellite-derived precipitation accumulation product. Comparing the images, the spatial placement of flooding with accumulated precipitation coincides well.

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Q: Can geostationary imagers see the very thin, very high Noctilucent Clouds? A: Yes and no, depending on the satellite, how data are processed, time of the year, time of the day and spectral band. Thanks to Simon Proud for this tweet using JMA‘s Advanced Himawari Imager (AHI):

Whoa, awesome view of #Noctilucent clouds over the North pole, seen by Japan's #Himawari satellite on the afternoon of 20th June.

This is one of the clearest views of noctilucent clouds I've ever seen, wonderful! pic.twitter.com/PZ8jAgOpW8

— Simon Proud (@simon_sat) June 21, 2022

Since NOAA’s ABI is a similar instrument to AHI it seems likely that ABI can also observe noctilucent clouds at times. Noctilucent clouds are possibly only observable in visible bands when they are off the earth’s edge, with space as a background, and when illuminated from certain angles. However, due to ground system processing in the generation of the ABI radiance files, most users cannot see data that the ABI scans off the Earth’s edge in space. Special processing of ABI data does allow to show off Earth pixels, such as in these examples with the moon and the Webb Space Telescope plume in space. Recall that the AHI Full Disk is made up of 23 swaths (as opposed to 22 for the ABI), so it scans a bit more space both north and south of the Earth.

An animation including the AHI 3.9 micrometer band shows the relationship between the Earth’s edge and the apparent cloud location. (A animated gif version.) Consider also the large apparent displacement of these high altitude (“shining at night”) clouds due to parallax.

Also see this image:

A fine display of #NoctilucentClouds just before midnight on June 20, across the northern sky. This was from latitude 51° N in southern Alberta, Canada. @NLCalerts pic.twitter.com/Miq2ckV2ni

— Alan Dyer (@amazingskyguy) June 21, 2022

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