To the CIMSS Inbox, From to the Alaska Ice Desk:

I noticed what I think are a pair of mesoscale convective vorticies forming on a boundary in the southeastern Beaufort Sea between the Mackenzie River Delta and the ice pack where there's still open water. I don't think there's much impactful going on, and there's no SAR to see the wind field yet but an interesting feature none the less. This is adaptive day/night band and overall the imagery wasn't great, but wanted to pass it along as an interesting feature to look at.

Indeed, the feature is very hard to see in the Day Night Band because of a lack of lunar illumination (the moon is a New Moon on November 1st). How did this feature evolve with time (can that be viewed?), and what did other VIIRS Imager Bands show?

In AWIPS, the Day Night Band imagery is shown as the Near Constant Contrast (NCC) product. The animation below shows Day Night Band imagery for the five hours between 1028 and 1528 UTC on 1 November. You will immediately note that the brightness of the scene varies considerably – because of the appearance and disappearance of Aurora on this date! It proved very difficult to enhance this NCC product to match the Adapative DNB shown above! (Note the position of Kaktovik in the image up top and the image below).

The I04 data below, at 3.74 µm, however, shows (faintly!) the two circulation centers at 1209 UTC.

The animation of the I05 data (infrared imagery at 11.45 µm), rescaled so that brightness temperatures are between 0 and -80^oC, below, shows the feature at 1209 UTC, and maybe you can infer its movement (I cannot) from these widely-spaced snapshots. But it’s an interesting feature to investigate.

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Added, Bill Line, NOAA/NESDIS at CIRA, forwarded along the following animation of Day Night Band images from two JPSS Satellites (NOAA-20 and NOAA-21). The swirls are near the western edge of the animation below and appear to be moving to the west. But the lack of illumination is making interpretation a challenge. Thanks for the imagery Bill!

Thanks to Mike Lawson at the Alaska Ice Desk for highlighting this ice-edge feature.

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GOES-East airmass RGB imagery, above, shows the evolution of a strong system that brought heavy rain to the central United States as well as snow over the western Great Lakes. The Potential Vorticity Anomaly that supported the surface cyclone, orange in the RGB shown above, starts over the Rocky Mountains and moves northeastward to the northern Plains before shifting more eastward across the Great Lakes at the end of the animation. Total Precipitable water fields from MIMIC, below (archived here), show the deep moisture drawn northward from the Gulf of Mexico that the system could access. Madison, WI, set a daily record rainfall — 2.21″ — on 30 October. You might also infer deep moisture in the airmass RGB where the field is a deep green color.

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The images below compare GFS pressures on the 2 PVU surface (source) to the airmass RGB fields at the same time. There is good (but not perfect) spatial agreement between the modeled initial pressure maximum on the 2 PVU surface (that is, a lowered tropopause associated with the Potential Vorticity Anomaly) and the orange-hued region in the airmass RGB.

GOES Imagery with its excellent temporal resolution is what a forecaster is going to use to monitor the evolution of a system. Polar Orbiter data offers unique fields that aren’t really available from basic GOES imagery. Suomi-NPP overflew the region and Microwave-derived estimates of rain rate are shown below (the data are mislabeled as coming from NOAA-20) in a toggle with various GOES-16 bands at the same time. The band of heavier precipitation is associated with strong low-level frontogenesis (here is a 12-h NAM forecast of 700-mb Frontogenesis — source — at 1800 UTC on 31 October). In the toggle below, one of the Band 13 images has been rescaled to allow the display to use the entire color bar. It is time to make that adjustment in the upper midwest as very cold cloud tops that accompany strong convection are not likely until next Spring!

GOES data can also be used to estimate rain rate. In addition to the level 2 rain rate product, GREMLIN (GOES Radar Estimation via Machine Learning to Inform Numerical Modeling), which field is shown below in a toggle with ATMS estimates of Rain Rate from NOAA-20 (as labeled this time), is available. There is excellent agreement between the two estimates especially regions of heavier precipitation.

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Microwave data can also give snowfall estimates, as displayed at this website. Estimates from a variety of Low Earth Orbit (LEO) satellites that have Microwave Sounders on board are shown below for times between 1500 and 1900 UTC on 31 October 2024.

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A prolonged eruptive period of Popocatépetl occurred during 23-30 October 2024. An animation of GOES-16 (GOES-East) Nighttime Microphysics RGB + daytime True Color RGB images from the CSPP GeoSphere site (above) displayed the volcanic plumes — which often exhibited brighter shades of magenta at night, and a hazy appearance during the day — during its multiple eruptive phases (the most robust of which began around 1631 UTC on 25 October).

Preliminary/non-operational GOES-19 Ash RGB images (below) also showed the periodic pulses of ash from Popocatépetl.

A radiometrically-retrieved Ash Height product from the NOAA/CIMSS Volcanic Cloud Monitoring site (below) showed that the volcanic plume occasionally reached altitudes of 12 km or greater (magenta).

The aforementioned robust eruption that began around 1631 UTC on 25 October ejected ash to an estimated altitude of 32000 ft (FL320) — and southwesterly winds ahead of a 300 hPa trough over Mexico transported this ash across the Gulf of Mexico. On 26 October, there were several Pilot Reports (PIREPs) of Volcanic Ash (VA) over the eastern Gulf of Mexico, near or over the west coast of Florida, at altitudes of 25000-28000 ft (FL250-FL280) (below).

The #SO2 plume from #Popocatépetl, as shown here by #TROPOMI on 10/27/2024, extends more than 3,500 miles to the east of the #volcano over the Atlantic Ocean. #mcidas pic.twitter.com/6LwAXXQllC

— Robert Carp (@rmcarp) October 28, 2024

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The Community Satellite Processing Package (CSPP) software Polar2Grid supports the creation of imagery using Microwave Integrated Retrieval Software (MIRS) algorithms. This is useful because on-line sources of imagery occasionally go missing. Consider, for example, the Snowfall Rate values that are available at this site from GINA. NOAA-20 was viewing parts of Alaska, but no data were created. Polar2Grid can help.

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Polar2Grid is self-contained unix-based software that creates reprojected imagery from JPSS data that can be found online. One set of online data sources are the NOAA/NESDIS/Amazon Web Service bit buckets for Suomi-NPP (here) and for NOAA-20 (here). JPSS Satellites include many different data types. For MIRS products (a list of MIRS products that Polar2Grid can create is here), click on “NPR-MIRS-IMG” as highlighted below. Clicking will reveal different years, and then different months and days. Click through until you reach the date you want; for this case, that’s 28 October 2024.

Once you get to the date you are interested in, you’ll see many pages of files, because each file covers about 30 seconds of information from the satellite. Page 14, shown below (with 100 files per page!), shows data ending at 1226 UTC on 28 October. For this blog post, I’m looking for data (based on this prediction of the NOAA-20 orbit) between 1211 and 1217 UTC on 28 October (meaning I’d have to scroll up on this page online).

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After downloading the files, and also the files for Suomi NPP near 1324 UTC on the 28th, it’s time to create imagery. This is done using the -r mirs flag (that is, the MIRS reader) in Polar2Grid. The commands I used (from within the $POLAR2GRID_HOME/bin directory) are below. Prior to running polar2grid, I created and defined a grid (‘ANC’) and stored the grid parameters in a file (‘ANC.yaml’) using the grid helper command: ./p2g_grid_helper.sh ANC -155.0 62.0 2000 -2000 1440 960 > ANC.yaml ; the grid is centered at 62^oN, 155^oW, has 2000-m resolution in the east-west and north-south directions, and the grid has dimensions of 1440×960.

./polar2grid.sh -r mirs -w geotiff -p sfr -g ANC –grid-configs ./ANC.yaml -f ./path_to_N20_data/NPR-MIRS-IMG*n20*s20241028*
./polar2grid.sh -r mirs -w geotiff -p sfr -g ANC –grid-configs ./ANC.yaml -f ./path_to_NPP_data/NPR-MIRS-IMG*npp*s2024102813*

Then I added a predefined colormap to the .tif file that Polar2Grid created, and then added coastlines, lat/lon lines, and a colorbar to the final image with the commands below.

./add_colormap.sh /path_to_colortable/SFR_colortable.txt noaa20_atms_sfr_20241028_121155_ANC.tif
./add_colormap.sh /path_to_colortable/SFR_colortable.txt npp_atms_sfr_20241028_132706_ANC.tif
./add_coastlines.sh –add-coastlines –add-grid –grid-D 5.0 5.0 –grid-d 5.0 5.0 –grid-text-size 16 –add-colorbar –colorbar-height 32 –colorbar-text-size 24 –colorbar-tick-marks 5.0 –colorbar-minor-tick-marks 5 noaa20_atms_sfr_20241028_121155_ANC.tif
./add_coastlines.sh –add-coastlines –add-grid –grid-D 5.0 5.0 –grid-d 5.0 5.0 –grid-text-size 16 –add-colorbar –colorbar-height 32 –colorbar-text-size 24 –colorbar-tick-marks 5.0 –colorbar-minor-tick-marks 5 npp_atms_sfr_20241028_132706_ANC.tif

The imagery was annotated, and the toggle below is the result. The Suomi NPP image below compares well with the image in the toggle at the top of the blog post, and the earlier NOAA-20 Snow Fall Rate has been created; the slow progress of enhanced snowfalls approaching the Anchorage area can be discerned.

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