1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed clusters of thunderstorms that developed along and just behind a cold front moving eastward across Minnesota on 08 August 2020. The northernmost hail-producing thunderstorm in Minnesota exhibited an Above-Anvil Cirrus Plume (reference | VISIT training); in addition, a decaying thunderstorm complex in southeastern North Dakota eventually revealed the cyclonic circulation associated with a Mesoscale Convective Vortex.

GOES-16 Visible images (above) and Infrared images (below) included time-matched SPC Storm Reports.

A toggle between time-matched NOAA-20 VIIRS Infrared Window (11.45 µm) and GOES-16 “Clean” Infrared Window (10.35 µm) images (below) demonstrated the northwestward parallax displacement of GOES-16 cloud-top features (note: the same color enhancement enhancement has been applied to both images). Due to the 375-meter spatial resolution of VIIRS imagery, it was able to sense overshooting top infrared brightness temperatures as cold as -77.8ºC (compared to -65.7ºC with GOES-16). The higher resolution VIIRS image also provided a clearer depiction of the cloud-top gravity waves and tendrils of transverse banding.

A GOES-16 Infrared image with parallax displacement vectors and magnitudes (in km) from this site is shown below. For a 50,000 foot cloud top over southern Minnesota, the parallax adjustment was to the southeast at a distance of 21 km (13 miles) — this corresponded well to what was seen in the NOAA-20/GOES-16 comparison above.

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A previous blog post (link) detailed how to access NOAA CLASS to create Gridded NUCAPS (NOAA-Unique Combined Atmospheric Processing System) imagery from those data.  (You can also view some gridded NUCAPS fields here;  click here to see the 850-mb field of Temperature from that site, it is very similar to the imagery above).   This post details how to use the CSPP QuickLooks software package to create imagery at different levels.  These QuickLook fields give good information quickly and at many different levels for Direct Broadcast data.

Download the Sounder QuickLook software for Linux from the CIMSS website here.  Documentation is also available at the download website.  The files to download are shown in this graphic. The package is self-contained and requires only unzipping and un-tarring.

After downloading, define the $CSPP_SOUNDER_QL_HOME variable as the directory where the package sits on your unix platform.  Then, set up the environment with the command:  source $CSPP_SOUNDER_QL_HOME/cspp_sounder_ql_env.sh.

This software package works on NUCAPS EDR (Environmental Data Records) files created at Direct Broadcast sites by CSPP (that are also available after some time from CLASS), and those files can be found at websites such as this one: ftp://ftp.ssec.wisc.edu/pub/eosdb/ — underneath this are directories for NOAA-20 (‘j01’) and Suomi-NPP (‘npp’). For example, NOAA-20 data from 7 August 2020 from the ~1747 UTC overpass is at ftp://ftp.ssec.wisc.edu/pub/eosdb/j01/crisfsr/2020_08_07_220_1747/ (This website is not preserved forever but will go away after about a week. The directory includes an edr subdirectory that contains the files needed; a typical filename looks like this:  NUCAPS-EDR_v2r0_j01_s202008071752319_e202008071753017_c202008071830250.nc; it is the EDR for NOAA-20 and it contains data on 7 August 2020 from 1752 through 1753 UTC. The directory will include up to about 18 of these EDRs (the number depends on how long the satellite is within view of the Direct Broadcast antenna at CIMSS).

How do you create the QuickLooks?

1. Move the EDR files to your machine, and that’s easily done with wget ftp://ftp.ssec.wisc.edu/pub/eosdb/j01/crisfsr/2020_08_07_220_1747/edr/NUCAPS-EDR*.  Of course, the yyyy_mm_dd_jdy_hhmm value (2020_08_07_220_1747 above) changes with each satellite overpass!
2. Create a list of the files in that directory, i.e., files=$CSPP_SOUNDER_QL_HOME/data/NUCAPS-EDR*
3. Invoke the shell script from $CSPP_SOUNDER_QL_HOME/scripts/ql_level2_image.sh "$files" NUCAPS --dset temp --pressure 850.   This will create an image, shown above, that is a temperature mapping at the closest pressure level to 850 mb in the NUCAPS retrieval. (Pressure levels in the Radiative Transfer Model that is used by NUCAPS are listed here;  in the map label above, note that values are truncated, not rounded).  You can also map dewpoint temperature (dwpt), relative humidity (relh) and mixing ratio (wmix). By default, temperature scaling matches the bounds of the image, but you can specify the bounds if needed, using --plotMin=250.0 --plotMax=300.0, for example.  The time of the image is the time of the first scan line — for this ascending pass, it’s the southernmost line.  In this QuickLook image, the airmass difference between the relatively cool air over Ohio/Indiana and the warmer air to the south is apparent.

You can also create a QuickLook SkewT/logP plots for each scan. This produces one SkewT per ScanLine, at the mid-point along the scanline that contains 30 separate profiles.   The sounding below was produced by this command:

./ql_level2_skewt.sh ./data/NUCAPS-EDR_v2r0_j01_s202008071755119_e202008071755417_c202008071831450.nc NUCAPS

The SkewT has characteristics that suggest the presence of clouds.  What did this particular sounding look like in AWIPS?  That’s shown below.  In AWIPS, the sounding also terminated at about 550 mb, and the temperature and dewpoint lines above that level match the Quick Look sounding shown above.

NUCAPS Sounding Availability points from this NOAA-20 pass are shown below. The sounding point — in yellow — that is circled in blue is the one shown above. The sounding just to the east of that point — a green point that gives useful information down into the boundary layer — is shown here. Quick Looks choose the mid-point sounding along the line, and sometimes, as in this case, the retrieval that produced the profile did not converge.

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A sequence of 3 VIIRS True Color Red-Green-Blue (RGB) images from Suomi NPP and NOAA-20 as visualized using RealEarth (above) showed plumes of blowing dust moving off the coast of Namibia and South Africa on 07 August 2020.

EUMETSAT Meteosat-11 Visible (0.6 µm) images (below) displayed the motion of the dust plumes during the daytime hours.

A plot of surface data from Luderitz, Namibia (station identifier FYLZ) is shown below; it indicated that winds gusted to 36 knots (41 mph) at 08 UTC.

H/T to Santiago Gassó for bringing this event to our attention.

#sentinel2 had a not-so-centered overpass, but some of the northern plumes seem to me like sand although there are plumes coming of the pan further inland. #highlatitudedust @sheffield_dust @jobullard https://t.co/pBaIQf2Z3v pic.twitter.com/4hwnR59CNa

— Santiago Gassó (@SanGasso) August 9, 2020

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VIIRS Today, like MODIS today, subsects the US into 8 sectors of equal size. If you live in central South Carolina, or in the middle of Florida, for example, the Sector 7/Sector 8 seam is right on top of you. Perhaps you want to view the entire Great Lakes in one image, rather than a split between Sector 3 and Sector 4. (This image, from this website, shows the 8 sectors over the United States).  There are easy ways to create seam-spanning imagery.

Because the sectors are of fixed and unchanging locations and sizes (1300×1500 for 1-km resolution, 5200×6000 for 250-m resolution), it’s a simple matter to create a script to access the imagery, cut parts out, and paste them back together. For this task, I use ImageMagick, a useful, scriptable image manipulation package. The two grid sizes (950x1100 for sector USA3, 700x1100 for sector USA4) and offsets (+351+101 for sector USA3,+0+101 for sector USA4) were determined by trial and error that took about 5 minutes.

The first script below is for the 1-km resolution images. The second script below is for 250-m resolution images; it has a multiplication factor of 4 applied. These scripts are on a unix system, and it would be simple enough to put some date-enabling at the front end to make this useful in a cron. That exercise, as they say, is left to the reader.

wget http://ge.ssec.wisc.edu/viirs-today/images/noaa20/true_color/2020_08_03_216/n2.20216.USA3.143.1000m.jpg
wget http://ge.ssec.wisc.edu/viirs-today/images/noaa20/true_color/2020_08_03_216/n2.20216.USA4.143.1000m.jpg
convert -crop 950x1100+351+101 n2.20216.USA3.143.1000m.jpg test1_1000.jpg
convert -crop 700x1100+0+101 n2.20216.USA4.143.1000m.jpg test2_1000.jpg
convert test1_1000.jpg test2_1000.jpg +append n2.20216.GreatLakes.143.1000m.jpg

wget http://ge.ssec.wisc.edu/viirs-today/images/noaa20/true_color/2020_08_03_216/n2.20216.USA3.143.250m.jpg
wget http://ge.ssec.wisc.edu/viirs-today/images/noaa20/true_color/2020_08_03_216/n2.20216.USA4.143.250m.jpg
convert -crop 3800x4400+1401+401 n2.20216.USA3.143.250m.jpg test1_250.jpg
convert -crop 2800x4400+0+401 n2.20216.USA4.143.250m.jpg test2_250.jpg
convert test1_250.jpg test2_250.jpg +append n2.20216.GreatLakes.143.250m.jpg

The 1-km resolution True-Color imagery from NOAA-20 (‘n2’ in the file name; ‘n1’ is Suomi-NPP) for the Great Lakes on day 216 of the years 2020 (i.e., 3 August 2016, represented as 20216 in the url) is shown above; it spans sectors USA3 and USA4. The 250-m resolution image is here.

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From an email received from South Carolina:  Our area is always split between USA7 and USA8, making it hard to use the sectorized imagery.

A script for that region, in this case for Day Night Band imagery, is below. This script accesses both Suomi-NPP and NOAA-20 data.

wget http://ge.ssec.wisc.edu/viirs-today/images/noaa20/night_dynamic/2020_08_05_218/n2.20218.USA8.DNBD.1000m.jpg
wget http://ge.ssec.wisc.edu/viirs-today/images/noaa20/night_dynamic/2020_08_05_218/n2.20218.USA7.DNBD.1000m.jpg
convert -crop 800x750+501+0 n2.20218.USA7.DNBD.1000m.jpg test1_1000.jpg
convert -crop 800x750+0+0 n2.20218.USA8.DNBD.1000m.jpg test2_1000.jpg
convert test1_1000.jpg test2_1000.jpg +append n2.20218.SOUTHCAROLINA.DNBD.1000m.jpg
wget http://ge.ssec.wisc.edu/viirs-today/images/snpp/night_dynamic/2020_08_05_218/n1.20218.USA8.DNBD.1000m.jpg
wget http://ge.ssec.wisc.edu/viirs-today/images/snpp/night_dynamic/2020_08_05_218/n1.20218.USA7.DNBD.1000m.jpg
convert -crop 800x750+501+0 n1.20218.USA7.DNBD.1000m.jpg test1_1000.jpg
convert -crop 800x750+0+0 n1.20218.USA8.DNBD.1000m.jpg test2_1000.jpg
convert test1_1000.jpg test2_1000.jpg +append n1.20218.SOUTHCAROLINA.DNBD.1000m.jpg

The Day Night Band Composite from NOAA-20 is shown below. Click here to see the Suomi-NPP image.

This technique would work with MODIS Today imagery as well.

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