GOES-16 Cryosphere Level 2 Products

February 14th, 2022 |
GOES-16 Ice Concentration, 1300 UTC on 4 February 2022 (click to enlarge)

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.

GOES-16 Ice Mask, 1300 UTC on 14 February 2022 (Click to enlarge)

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.

GOES-16 Sea Ice Concentration, hourly from 0700-1600 UTC on 14 February 2022 (Click to enlarge)

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.

RADARSat Constellation Mission (RCM)-3 NRCS imagery over Lake Ontario and eastern Lake Erie, 2307 UTC on 13 February 2022 (Click to enlarge)

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.

GOES-16 Cryosphere Ice Surface Temperature and GOES-16 Cloud Mask, 1300 UTC on 14 February 2022 (Click to enlarge)

Solar eclipse shadow in the Southern Hemisphere

December 4th, 2021 |

GOES-16 Near-Infrared “Snow/Ice” (1.61 µm) images (credit: Tim SchmIt, NOAA/NESDIS) [click to enlarge | MP4]

GOES-16 (GOES-East) Near-Infrared “Snow/Ice” (1.61 µm) images (above) showed the shadow of a total solar ecliipse in the Southern Hemisphere on 04 December 2021. Even though the 1.61 µm imagery is at a lower (1 km) spatial resolution, it provided better contrast than higher-resolution (0.5 km) 0.64 µm “Red” Visible imagery, helping to highlight the shadow (below). Note that the shadow passed over the Antarctic Peninsula.

GOES-16 “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (credit: Tim Schmit, NOAA/NESDIS) [click to enlarge]

GOES-16 CIMSS True Color RGB images (below) provided another view of the eclipse shadow’s progression. 

GOES-16 CIMSS True Color RGB images (credit: Tim Schmit, NOAA/NESDIS) [click to play animated GIF | MP4]

In a 3-panel comparison of GOES-16 “Red” Visible (0.64 µm), Near-Infrared “Snow/Ice” (1.61 µm) and Shortwave Infrared (3.9 µm) images (below), note that the lack of solar reflection within the eclipse shadow led to cooler 3.9 µm brightness temperatures (lighter shades of gray).    

GOES-16 “Red” Visible (0.64 µm, top), Near-Infrared “Snow/Ice” (1.61 µm, middle) and Shortwave Infrared (3.9 µm, bottom) images (credit: Tim Schmit, NOAA/NESDIS/ASPB) [click to play animated GIF | MP4]

The shadow was also apparent in GOES-17 (GOES-West) images (below).

GOES-17 Near-Infrared “Snow/Ice” (1.61 µm) images [click to play animated GIF | MP4]

A composite of POES AVHRR Visible (0.63 µm) swaths around 0700 UTC (below) showed the shadow extending southward across South Georgia and the South Sandwich Islands and reaching the coast of Antarctica. 

Composite of POES AHVRR Visible (0.63 µm) swaths [click to enlarge]

In addition, portions of the solar eclipse shadow could be seen in True Color RGB images from Suomi-NPP and NOAA-20, as viewed using RealEarth (below).

VIIRS True Color RGB images from Suomi-NPP and NOAA-20 [clck to enlarge]

This blog post discusses AMRC/AWS staff viewing the partial eclipse from Antarctica’s McMurdo Station.

A68a Update

December 2nd, 2020 |

A very large iceberg broke off the Larsen-C Ice Shelf on the Antarctic Peninsula in July 2017 (recall this CIMSS Satellite Blog post, or this more recent post). While NOAA’s GOES-16 ABI visible sensors may not be ideal, they can monitor the iceberg’s location if the cloud cover is not too thick, as shown in the “natural color” animation. A similar loop, in the animated gif format. These composite images include information from ABI “blue” and “red” visible bands, along with the near-infrared “vegetation” band. A sample still image from November 21, 2020. More information can be found in the quick guide.

A GOES-16 natural color animation, using images at 15:30 UTC each day. The first day is November 4, while the last day is December 2, 2020.

Since it was relatively cloud-free for several hours on 02 December, an animation of GOES-16 “Red” Visible (0.64 µm) images is shown below — note the presence of numerous small ice floes that had separated from the edges of A68a, and were circulating within the various ocean currents surrounding the large iceberg as it continued its slow drift toward South Georgia island. 

GOES-16

GOES-16 “Red” Visible (0.64 µm) images from 02 December 2020 [click to play animation | MP4]

The geo2grid software was used to generate the images for these animations.

Thanks to a recent tweet by Simon Proud, showing a GOES-16 animation of A68a:

What has the Large Iceberg (A68) been up to this year?

March 31st, 2020 |

GOES-16 True Color RGB images [click to play animation]

GOES-16 True Color RGB images [click to play animation | MP4]

A very large iceberg broke off the Larsen-C Ice Shelf on the Antarctic Peninsula in July 2017 (recall this CIMSS Satellite Blog post). While NOAA’s GOES-16 ABI visible sensors may not be ideal, they can monitor the iceberg’s location if the cloud cover is not too thick. The animation above shows the first 31 days of 2020, with just one image per day. More information from the National Ice Center.

H/T to @annamaria_84 for this tweet using Sentinel3 images:

 

———–Update————————————-

Here’s a similar loop (mp4), but showing hourly GOES-16 “natural color” (composite) imagery, click to play animation: