GOES-17 (left) and Himawari-8 (right) visible (0.64 µm) imagery over Fiji, 2100 UTC on 13 December through 0500 UTC on 14 December (Click to animate)

An active area of tropical weather has spawned two tropical cyclones that bracketed the islands of Fiji early on 14 December. Himawari-8 (data courtesy the Japanese Meteorological Agency, JMA) and GOES-17 both viewed the two storms, with Yasa on the left and Zazu on the right, and stereoscopic views are shown above. (To view the imagery in three dimensions, relax/cross your eyes until three images are present, and focus on the image in the center). Click here for a full-sized mp4, and here for an animated gif.

The storms had an interesting development, as shown below in a 3-day Himawari-8 Clean Window infrared imagery mp4 animation (Click here for a large animated gif of the same scene) from 10-13 December 2020. Yasa in particular developed in a region of considerable shear and initially followed a circuitous route (shown in this graphic from RSMC Fiji), but it has since moved into a more favorable environment.  Yasa also absorbed the remains of Tropical Storm #4.

Himawari-8 Clean window infrared (10.41 µm) imagery, 0000 UTC on 10 December – 2350 UTC on 13 December (Click to animate;  data courtesy JMA)

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Added:  The morning view of the storms, above, from 1900 UTC on 14 December reveals that Zazu is becoming sheared.  The low-level center is exposed with convection shifted to the east.  This is consistent with shear analyses from the SSEC Tropical website, below, that shows westerly shear over the storm.

For more information on these storms, refer to the SSEC tropical website (link), or to the RSMC in Fiji (link). At present, Yasa is forecast to make landfall in Fiji later this week as a very strong storm. Interests there should monitor this storm closely.

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GOES-16 (GOES-East) Dust RGB images (above) displayed signatures of blowing dust (brighter shades of pink) moving southward across far southeastern New Mexico and southwestern Texas on 13 December 2020. Strong winds behind a cold front — gusting in excess of 40 knots or 46 mph — reduced surface visibility to 2.5 miles at Hobbs, New Mexico (KHOB) and 1 mile at Midland, Texas (KMAF).

GOES-16 True Color RGB images created using Geo2Grid (below) showed the tan-colored signature of blowing dust increase during the afternoon hours leading up to sunset.

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GOES-16 (GOES-East) Day Snow-Fog Red-Green-Blue (RGB), “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (above) showed and undular bore propagating slowly north-northwestward across northeastern Minnesota and western Lake Superior on 11 December 2020. Also evident on the RGB and 1.61 µm images was the presence of a few industrial plumes — with their point sources being north of Hibbing — moving south-southwestward. These plume sources were likely large coal-fired power plants and other industrial sites located across that region; emissions from these industrial sources acted as cloud condensation nuclei, causing a higher concentration of smaller supercooled cloud droplets downwind of each plume source.

In a comparison of Suomi NPP VIIRS Visible (0.64 µm), Near-Infrared (1.61 µm) and Shortwave Infrared (3.74 µm) images at 1734 UTC (below), the industrial plumes appeared warmer (shades of green) due to enhanced reflection of incoming solar radiation by the smaller cloud droplets within the plumes.

Plots of rawinsonde data from International Falls, Minnesota (below) depicted a strong temperature inversion based around 1.2 km — the undular bore was likely ducted within this inversion.

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This blog has featured numerous blog posts that use visible imagery from two Geostationary Platforms (e.g., GOES-16/GOES-17 ; Himawari-8/GEOKOMPSAT-2).  Different cloud heights can be perceived in that imagery (for those who have mastered the art of crossing their eyes!).

GOES-R-type satellites also produce a Level 2 Product:  Cloud Top Height.  Can that product be used in concert with the Stereoscopic imagery to quantify the height differences seen in visible imagery?  The image above was created using Geo2Grid and ImageMagick: Geo2Grid to create the GOES-16 (left) and GOES-17 (right) visible imagery, ImageMagick to paste them together.  The GOES-R data (Full Disk in this case) have been remapped to a common projection. The scripts that does this sits below. (Click here to view Geo2Grid documentation).


../p2g_grid_helper.sh SWUSStereo -115.0 34.0 2000 -2000 960 720 > $GEO2GRID_HOME/SWStereo.conf
#
#
../geo2grid.sh -r abi_l1b -w geotiff -p C02 -g SWUSStereo --grid-configs $GEO2GRID_HOME/SWStereo.conf --method nearest -f /arcdata/goes_restricted/grb/goes17/2020/2020_12_11_346/abi/L1b/RadF/OR_ABI*G17_s2020346180*.nc
../geo2grid.sh -r abi_l1b -w geotiff -p C02 -g SWUSStereo --grid-configs $GEO2GRID_HOME/SWStereo.conf --method nearest -f /arcdata/goes_restricted/grb/goes16/2020/2020_12_11_346/abi/L1b/RadF/OR_ABI*G16_s2020346180*.nc
../add_coastlines.sh --add-borders --borders-resolution=h --borders-outline='black' --add-coastlines --coastlines-outline='blue' --coastlines-resolution=h --add-grid --grid-text-size 12 --grid-d 10.0 10.0 --grid-D 10.0 10.0 GOES-17_ABI_RadF_C02_20201211_180???_SWUSStereo.tif
../add_coastlines.sh --add-borders --borders-resolution=h --borders-outline='black' --add-coastlines --coastlines-outline='blue' --coastlines-resolution=h --add-grid --grid-text-size 12 --grid-d 10.0 10.0 --grid-D 10.0 10.0 GOES-16_ABI_RadF_C02_20201211_180???_SWUSStereo.tif
convert GOES-16_ABI_RadF_C02_20201211_180???_SWUSStereo.png GOES-17_ABI_RadF_C02_20201211_180???_SWUSStereo.png +append GOES-1617Stereo_ABI_RadF_C02_20201211_1800_SWUSStereo.png

Unfortunately, Geo2Grid doesn’t (yet!) display Level 2 products. But AWIPS does. A somewhat later Stereoscopic image (1941 UTC on 11 December) is shown below. GOES-R data (CONUS and PACUS in this case) are shown in a common projection, with GOES-16 shown on the left and GOES-17 shown on the right.

Can quantitative information from the Cloud Top Height Level 2 product, shown below, be easily incorporated into stereoscopic imagery?

First, I tried making side-by-side imagery with GOES-16 Visible and GOES-16 Cloud Top Heights. That is shown below.  Cross your eyes to combine the information.  Although one may be able to view something here — by aligning the state boundaries, your blogger did not find this side-by-side view useful — except in the conventional sense, seeing features in the visible to the left and corresponding information in the Level 2 product on the right.

Including the Cloud Top imagery to the right of the stereoscopic pair, however, did allow for a simple (although, perhaps, headache-inducing) comparison between the perceived height differences in the visible imagery and the quantitative differences in the Level 2 product.  If I had GOES-17 Cloud Heights, I would include those to the left of the visible pairs.

Perhaps the solution lies in color-enhancing the visible imagery based on the cloud top height.  That is work for the future.

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The Sandwich Product in AWIPS, a combination of visible imagery — proving texture — and infrared imagery providing color is one way to color the visible imagery based on cloud-top brightness temperatures (as a proxy for height).  A 2.5-hour animation of the Sandwich product is shown below. It does provide an interesting way to view heights of clouds!

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