Testing of GOES-16 and GOES-17 Mode 6 scan strategy

February 19th, 2019 |

GOES-16

GOES-16 “Red” Visible (0.64 µm) images [click to play animation]

Both GOES-16 (GOES-East) and GOES-17 (GOES-West) were placed into the Mode 6 scan strategy for a 3-day period of testing beginning at 1500 UTC on 19  February 2019 — which provides Full Disk images every 10 minutes (instead of every 15 minutes for the more common Mode 3 scan strategy). Further details on GOES-R series scan modes are available here and here. GOES-16 Full Disk “Red” Visible (0.64 µm) images are shown above, with Mid-level Water Vapor (6.9 µm) images below.

GOES-16 Mid-level Water Vapor (6.9 µm) images [click to play animation]

GOES-16 Mid-level Water Vapor (6.9 µm) images [click to play animation]

One of the more striking features over the North Atlantic Ocean was a rapidly-intensifying Hurricane Force low — an animation that cycles through GOES-16 Visible and Water Vapor images of this system is displayed below.

GOES-16 "Red" Visible (0.64 µm) and Mid-level Water Vapor (6.9 µm) images [click to play animation]

GOES-16 “Red” Visible (0.64 µm) and Mid-level Water Vapor (6.9 µm) images [click to play animation]

GOES-16 Air Mass RGB images from the AOS site (below) exhibited the orange-to-red hues of ozone-rich air within the atmospheric column due to a lowered tropopause associated with the rapidly deepening North Atlantic storm.

GOES-16 Air Mass RGB images [click to play animation | MP4]

GOES-16 Air Mass RGB images [click to play animation | MP4]

Looking to the west with GOES-17, Full Disk animations of Visible and Water Vapor images are shown below.

GOES-17 "Red" Visible (0.64 µm) images [click to play animation]

GOES-17 “Red” Visible (0.64 µm) images [click to play animation]

GOES-17 Mid-level Water Vapor (6.9 µm) images [click to play animation]

GOES-17 Mid-level Water Vapor (6.9 µm) images [click to play animation]

The more frequent 10-minute images allowed a short-lived signature of orographic waves within a transient dry slot immediately downwind (northeast) of Atka (PAAK) in the Aleutian Islands of Alaska  (below) — such a signature often indicates a high potential of turbulence. There were also areas of transverse banding seen with the jet stream cirrus just southeast of Atka (another satellite signature of turbulence).

GOES-17 Low-level (7.3 µm) and Mid-level (6.9 µm) Water Vapor images [click to play animation]

GOES-17 Low-level (7.3 µm, left) and Mid-level (6.9 µm, right) Water Vapor images [click to play animation]

Similar to what was seen over the North Atlantic, GOES-17 Air Mass RGB images (below) exhibited the orange-to-red hues of ozone-rich air within the atmospheric column due to a lowered tropopause poleward of the jet stream axis as it moved northeastward across the Aleutians.

GOES-17 Air Mass RGB images [click to play animation | MP4]

GOES-17 Air Mass RGB images [click to play animation | MP4]

Small Eddy and coastal jet off the coast of Northern California

May 4th, 2017 |

GOES-16 Visible (0.64 µm) from 1245 through 2200 UTC on 4 May 2017 (Click to play mp4 animation)

GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing.

One of the two GOES-16 Mesoscale Sectors was moved from its default position over the eastern United States and placed over the west coast of the United States on 4 May 2017. This allowed 1-minute imagery of a small-scale coastal eddy between Cape Mendocino and Pt. St. George near Crescent City, above, and an associated coastal jet. (Click here to play 300-meg Animated Gif; alternatively, this animation shows the eddy from 1600-1900 UTC as displayed in AWIPS (courtesy Dan Miller, WFO DLH))

A zoomed-in Visible animation of the coastal eddy is shown below; NWS Eureka described it as “one of the best examples of these coastal eddies seen in quite a while”.

GOES-16 Visible (0.64 µm) images, with hourly surface reports plotted in yellow (Click to animate)

GOES-16 Visible (0.64 µm) images, with hourly surface reports plotted in yellow (Click to animate)

GOES-16 Visible 0.64 µm imagery is able to capture not only the eddy, but also the northerly low-level jet that develops off the coast of Cape Mendocino, swiftly moving clouds southward around that feature. A small eddy also develops south of Cape Mendocino. Note also the abundance of cirrus clouds flowing northward along the coast.

The dimensions of this eddy are approximately 70 km in the along-shore direction and 55 km perpendicular to the shore, yet GOES-16 is able to capture and resolve many small-scale cloud bands. The small cloud band streaming south around Cape Mendocino, for example, is only about 6 km wide and is well-resolved; if GOES-16 becomes GOES-East at 75 W Longitude, this is the type of resolution that can be expected in Salt Lake City.

It should be noted that none of the models (including the hourly RTMA, below) resolved this eddy feature.

Suomi NPP VIIRS Visible (0.64 µm) image, with RTMA surface winds {Click to enlarge)

Suomi NPP VIIRS Visible (0.64 µm) image, with RTMA surface winds {Click to enlarge)

Thanks to Dan Miller, Science and Operations Officer (SOO) in Duluth for calling this awesome feature to our attention!

Middle and upper-atmospheric wave structures in the vicinity of a subtropical jet stream

April 4th, 2016 |

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images, with ECMWF model maximum wind isotachs [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images, with ECMWF model maximum wind isotachs [click to enlarge]

A strong (120-knot) subtropical jet stream was moving eastward across the Gulf of Mexico during the 03 April – 04 April 2016 period. During the overnight hours between these 2 days, a Suomi NPP VIIRS Day/Night Band (0.7 µm) image at 0753 UTC (above) revealed a large packet of arc-shaped mesospheric airglow waves south of the axis of the jet stream (as indicated by isotachs of the maximum tropospheric wind speed from the ECMWF model). Note how there were no cloud features which corresponded to these waves in the 0753 UTC VIIRS Infrared Window (11.45 µm) image; since the Moon was in the waning Gibbous phase (at 13% of Full), there was very little lunar illumination of cloud features, so airglow — essentially the “night glow” emitted from a variety of high-altitude (80-105 km) gases (primarily the sodium layer) near the mesopause — was allowing these high-altitude waves to be detected using the sensitive Day/Night Band (reference: “Suomi satellite brings to light a unique frontier of nighttime environmental sensing capabilities”).

During the subsequent daytime hours on 04 April, more interesting (tropospheric) waves were seen in the vicinity of this subtropical jet stream — small packets of waves that were propagating westward, against the ambient flow –one over Florida/Georgia/South Carolina, and another over South Texas. Unfortunately, these features fall into the “What the heck is this?” blog category, so no coherent explanation of them can be offered at this time.

GOES-13 Water Vapor (6.5 µm) images, with ECMWF model maximum wind isotachs [click to play animation]

GOES-13 Water Vapor (6.5 µm) images, with ECMWF model maximum wind isotachs [click to play animation]

An interesting question from Shea Gibson:

Low-level “barrier jet” along the southeast coast of Greenland

December 29th, 2013 |
GOES-13 6.5 µm water vapor images with Metop ASCAT scatterometer winds and surface METARs and surface analyses (click to play animation)

GOES-13 6.5 µm water vapor images with Metop ASCAT scatterometer winds and surface METARs and surface analyses (click to play animation)

AWIPS images of GOES-13 6.5 µm water vapor channel data with available overpasses of Metop ASCAT surface scatterometer winds (above; click image to play animation) revealed the presence of a low-level “barrier jet” along the southeast coast of Greenland on 29 December 2013. Maximum ASCAT wind speeds were 58 knots at 12:16 UTC, 62 knots at 13:57 UTC, and 62 knots at 22:09 UTC. It is interesting to note that a secondary area of low pressure was seen rotating around the primary low, and appeared to be rapidly intensifying judging from the quick development of a “corkscrew” appearance on the water vapor imagery near the end of the animation. ASCAT winds along the northwestern periphery of this secondary low were as high as 53 knots at 22:09 UTC.

The cyclonic circulation around the quasi-stationary area of low pressure located east of Greenland encountered the abrupt rise in topography of the island (below), which caused an acceleration of the flow known as a “barrier jet”.

Topography of Greenland, with Metop ASCAT scatterometer winds and surface METAR reports and surface analysis

Topography of Greenland, with Metop ASCAT scatterometer winds and surface METAR reports and surface analysis