Unusually low ice concentration in the Beaufort Sea and Chukchi Sea

September 13th, 2022 |

Suomi-NPP VIIRS Visible images [click to play animated GIF | MP4]

A sequence of Suomi-NPP VIIRS Visible images (above) showed a large area of ice-free water in the western Beaufort Sea and eastern Chukchi Sea north of Alaska — with limited sea ice concentration as far north as 80º N latitude — on 13 September 2022.  

False Color RGB images from NOAA-20 and Suomi-NPP, viewed using RealEarth (below) provided another depiction of the large ice-free region the Beaufort Sea (as well as adjacent portions of the Chukchi Sea).

False Color RGB images from NOAA-20 and Suomi-NPP [click to play animated GIF]

 Sea Ice Concentration (based on the NOAA Enterprise Algorithm) at 0000 UTC on 13 September (below) also showed limited ice coverage and concentration extending past 80º N latitude.

Sea Ice Concentration at 0000 UTC on 13 September [click to enlarge]

According to Rick Thoman (University of Alaska, Fairbanks), Beaufort Sea ice extent was the 9th lowest on record for this date:

Posted in Arctic, Cryosphere, NOAA-20, Red-Green-Blue (RGB) images, Suomi NPP, VIIRS | Comments Off on Unusually low ice concentration in the Beaufort Sea and Chukchi Sea

Sea ice in the Bering Sea

August 14th, 2022 |

GOES-18 True Color RGB images [click to play MP4 animation]

GOES-18 (GOES-West) True Color RGB images viewed using CSPP GeoSphere (above) showed the motion of sea ice filaments that had moved southward through the Bering Strait and into the northwestern Bering Sea (just off the coast of Chokotka Okrug, Russia) on 14 August 2022. 

A sequence of 375-meter resolution VIIRS False Color RGB images from NOAA-20 and Suomi-NPP viewed using RealEarth (below) displayed a more detailed view of the sea ice (brighter shades of cyan).

VIIRS False Color RGB images from NOAA-20 and Suomi-NPP [click to enlarge]

A 30-meter resolution Landsat-8 False Color RGB image (below) provided an even more detailed depiction of the sea ice structure and coverage.

Landsat-8 False Color RGB image [click to enlarge]

H/T to Rick Thoman (University of Alaska, Fairbanks), who pointed out that this sea ice was evident in the Bering Sea on 09 August. More information on this unusual sea ice event is available on this NWS SeaIce Program storymap.

===== 21 August Update =====

VIIRS False Color RGB images from Suomi-NPP and NOAA-20 [click to enlarge]

One week later, another sequence of VIIRS False Color RGB images from Suomi-NPP and NOAA-20 on 21 August (above) indicated that the sea ice had moved a bit farther to the southwest along the Chukotka coast, with much of it located within Mechigmenskiy Zaliv due south of Lorino. 

GOES-18 True Color RGB images (below) showed the motion of this sea ice during the day.

GOES-18 True Color RGB images [click to play MP4 animation]

Posted in Arctic, Cryosphere, GOES-18, Landsat, NOAA-20, RealEarth, Red-Green-Blue (RGB) images, Suomi NPP, VIIRS | Comments Off on Sea ice in the Bering Sea

GOES-18 is currently serving as GOES-West

August 1st, 2022 |

GOES-18 “Red” Visible (0.64 µm) and Mid-level Water Vapor (6.9 µm) images [click to play animated GIF | MP4]

Beginning at 1713 UTC on 01 August 2022, GOES-18 began serving as GOES-West during an operational interleave period — so GOES-18 imagery routinely became available in AWIPS. Examples of GOES-18 “Red” Visible (0.64 µm) and Mid-level Water Vapor (6.9 µm) images from a combination of the Alaska, Pacific-US (PACUS) and Hawai`i Sectors are shown above.

GOES-18 multi-panel images of the PACUS Sector (below) displayed all 16 spectral bands of the ABI instrument.

GOES-18 multi-panel images of the PACUS Sector [click to play animated GIF |MP4]

A closer view of GOES-18 multi-panel images centered on Tropical Storm Frank is shown below.

GOES-18 multi-panel images of Tropical Storm Frank [click to play animated GIF | MP4]

Farther to the north, GOES-18 Visible images centered over Alaska (below) revealed an impressive southwesterly surge of stratus across the Chukchi Sea, which was moving toward the Bering Strait and the coast of Siberia (where some sea ice could be seen along the coast and offshore).

GOES-18 “Red” Visible (0.64 µm) images [click to play animated GIF | MP4]

GOES-18 ABI data also replaced GOES-17 as GOES-West for users receiving imagery via GRB download. Some examples created by Tim Schmit (NOAA/NESDIS/ASPB) — using GOES-18 imagery downloaded by SSEC Satellite Data Services — are shown below.

This transition to GOES-18 will mitigate the degraded GOES-17 infrared imagery caused by its Loop Heat Pipe cooling issues. The Loop Heat Pipe system was re-designed for the GOES-18 ABI instrument. 

16-panel comparisons of GOES-17 and GOES-18 ABI imagery at 1230 UTC [click to enlarge]

Additional information and examples can be found on the Satellite Liaison Blog.

 

Posted in Arctic, GOES-17, GOES-18, Tropical cyclones | Comments Off on GOES-18 is currently serving as GOES-West

Anomalously-deep upper low brings light snow to northwestern Alaska

July 19th, 2022 |

GOES-18 Mid-level (6.9 µm) Water Vapor images, with plots of hourly surface weather type [click to play animated GIF | MP4]

GOES-18 images shown in this blog post are preliminary and non-operational

GOES-18 Mid-level Water Vapor (6.9 µm) images during the 18 July – 19 July 2022 period (above) showed a series of impulses rotating within the broader circulation of an anomalously-deep low pressure system that meandered over the Bering Strait region. Anomalously-cold air associated with this deep low helped to produce brief periods of unusual July snow at some locations across the Seward Peninsula and northwestern Alaska.

In GOES-18 Air Mass RGB images created using Geo2Grid (below), brighter shades of red highlighted the core of this broad low pressure system, where high-altitude ozone levels were elevated (due to an unusually low tropopause).

GOES-18 Air Mass RGB images [click to play animated GIF | MP4]


Plots of rawinsonde data at Nome, Alaska at 00 UTC and 12 UTC on 19 July 2022 [click to enlarge]

In fact, at 12 UTC on 19 July the low 500 hPa geopotential height value of 5269.3 meters from the Nome, Alaska rawinsonde report (above) established a new July record for that site. The 12 UTC sounding also suggested that the tropopause was located at an unusually low pressure level of 483 hPa — such a low tropopause height was supported by NOAA-20 Gridded NUCAPS data from the SPoRT site (below).

NOAA-20 Gridded NUCAPS Tropopause Height at 1236 UTC on 19 July [click to enlarge]

Posted in Arctic, GOES-18, NOAA-20, NUCAPS, Red-Green-Blue (RGB) images, Winter weather | Comments Off on Anomalously-deep upper low brings light snow to northwestern Alaska

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