GOES-16 Cryosphere products — Ice Mask, Ice Concentration and Ice Surface Temperature — have been developed and are in a testing phase. The AWIPS screenshot above shows ice concentrations over parts of Lakes Superior, Huron and Erie. These products are created over the Full Disk ABI domain in regions of clear sky only (clouds over Lakes Michigan and Ontario mean Ice Concentration is not computed there at 1300 UTC). The Ice Mask at the same time, below, shows ‘Day Ice’ (cyan) and ‘Night Ice’ (green) flags; cryosphere products are created day and night, but different algorithms are used: Bands 14 and 15 (11.2 µm and 12.2 µm, respectively) are used day and night; the daytime product also uses Bands 2, 3 and 5 (at 0.64 µm, 0.86 µm and 1.61 µm, respectively) as noted in the Advanced Theoretical Basis Document — ATBD — here.

The strength of ABI is frequency (every hour) of observations, so an animation, as shown below, will allow a user multiple views of the lakes; in partly cloudy (or clearing) conditions, values from one hour can augment values from other hours. An example is shown below with Ice Concentration over the Great Lakes. Clearing skies over Lake Erie allow for a more complete description of Lake Ice, whereas increasing clouds over western Ontario and western Lake Superior mean GOES-R Cryosphere observations are lost. In the absence of very strong winds, however, lake ice does not erode quickly, so although the observations are precluded by cloud cover, earlier observations likely remain valid. It is important to know where the clouds are, however, when viewing these products.

The utility of these clear-sky products with good temporal frequency is augmented in combination with all-sky products that give observations only once or twice daily — such as Synthetic Aperture Radar (SAR) ice observations that available here. For example, the 2307 UTC 13 February Normalized Radar Cross Section (NRCS) image (below) over eastern Lake Erie can be used to fill in information not available from the GOES-16 Cryosphere product.

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The AWIPS toggle below shows Ice Surface Temperature plotted below and on top of the Binary Cloud Mask. You will note that there are regions where Ice Surface Temperature is computed in regions where the Binary Cloud Mask shows clouds! How can this occur in Clear Sky products such as the Cryosphere products (a similar toggle could be created with Ice Concentration or Ice Mask)?

The Cloud Mask in AWIPS shows regions that are Clear or Cloudy — it is binary. The Cloud Mask actually has 4 different states (as noted here): Clear, Probably Clear, Probably Cloudy and Cloudy. The Cloud Mask in AWIPS assigns ‘Cloudy’ to all pixels that aren’t Clear: that includes ‘Probably Clear’, ‘Probably Cloudy’ and ‘Cloudy’ pixels. In contrast, the Cryosphere products are produced in regions that are both Clear, or Probably Clear (as noted in the ATBD). That’s why Cryosphere products can show up in regions that AWIPS shows are Cloudy.

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GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed a string of mesovortices over the eastern portion of Lake Superior, along with a small, isolated mesovortex just offshore in the western portion of Lake Superior on 13 February 2022. Increasing ice coverage was also seen along the edges of the lake.

Farther to the east, GOES-16 Visible images showed a large and well-defined mesovortex over Lake Huron, with smaller mesovortices along a northern Lake Michigan cloud band (below).

Finally, over southern Lake Michigan a distinct mesovortex developed along the southern end of a long lake cloud band that began to move inland across far southwestern Lower Michigan (below).

A closer look at the Lake Michigan vortex using 1-minute Mesoscale Domain Sector GOES-16 Day Cloud Phase Distinction RGB images (below) portrayed the shades of green indicative of glaciating convective clouds around the core of the mesovortex and the trailing Lake Michigan band. The confluence of the western periphery of the mesovortex with the trailing lake cloud band produced a prolonged period of heavy snow at Benton Harbor (KBEH) and up to 12 inches of snowfall at downwind locations in Berrien County, Michigan.

In a sequence of 1-minute GOES-16 Cloud Top Phase Distinction RGB and Cloud Top Phase derived product images from 2000-2100 UTC (below), the supercooled/mixed phase core of the inland mesovortex was surrounded by a ring of ice phase clouds — while the adjoining Lake Michigan cloud band was classified as a mixed-phase feature as it began to move inland.

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GOES-16 (GOES-East) Day Snow-Fog RGB images (above) showed the signature of widespread horizontal convective rolls — which highlighted areas where blowing snow was creating ground blizzard conditions — across parts of eastern North Dakota and far western Minnesota on 11 February 2022. The elongated bands of blowing snow were more concentrated where they were being channeled by strong northerly winds through the lower elevations of the Red River Valley (peak wind gusts included 60 mph in North Dakota and 56 mph in Minnesota). The surface visibility was briefly reduced to near zero at reporting sites such as Crookston MN (KCKN) and Wahpeton ND (KBWP).

A closer view using 1-minute Mesoscale Domain Sector GOES-16 Day Snow-Fog RGB images (below) showed portions of Interstate 29 (between Grand Forks KGFK and Fargo KFAR) and Interstate 94 (between Jamestown KJMS and Fargo KFAR) that were impacted by these bands of blowing snow.

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This event is also discussed at the Satellite Liaison Blog (link).

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This presentation from the TOWR-S Satellite Book Club details TOWR-S RPM 22 additions to AWIPS (additions spearheaded by Tim Schmit and Bill Line, both from NOAA/STAR) that add Level 2 product readouts to RGBs in AWIPS. Thus, for example, the Airmass RGB, above, is underlain by Level 2 products: Cloud Mask and Total Precipitable Water (TPW) and Level 2 Stability Indices (CAPE and Lifted Index). Those Level 2 products are all clear-sky only, however, so sampling in cloudy regions will not yield level 2 product information.

Adding Gridded NUCAPS fields (in the example above and below, total precipitable water has been added; one could also add CAPE and Lifted Index), is an effective way of including estimates of atmospheric thermodynamics in clear and cloudy regions that can then be sampled, as shown below with two sampling examples, one each in clear and cloudy skies. The sampling location is just northwest of the Clear Sky Mask value (i.e., the screen capture did not capture the cursor).

An efficient way to load these data in AWIPS is via a procedure. The augmented RGB loads are part of TOWR-S RPM 22.

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