GOES-15 Rapid Scan Operations (RSO) sector for American Samoa

December 15th, 2015

GOES-15 Visible (0.63 µm) images [click to play animation]

GOES-15 Visible (0.63 µm) images [click to play animation]

On 15 December 2015 NOAA/NESDIS conducted a test of the new GOES-15 (GOES-West) Rapid Scan Operations (RSO) sector for coverage of the American Samoa region (SSD message). GOES-15 Visible (0.63 µm, 1-km resolution) images during the test period between 1711 and 1957 UTC are shown above, with plots of surface observations for Pago Pago (station identifier NSTU) and Faleolo (station identifier NSFA). Note that visible images from the Full Disk scan at 1800 UTC and Southern Hemisphere sectors at :22 past each hour are also included in the animation; during routine operations, there are periods when only 1 image per hour is available (from the Southern Hemisphere sector) which covers American Samoa.

The full size of the American Samoa RSO sector is shown below.

GOES-15 Visible (0.63 µm) image showing the size of the American Samoa RSO sector [click to enlarge]

GOES-15 Visible (0.63 µm) image showing the size of the American Samoa RSO sector [click to enlarge]

Displayed below is the American Samoa RSO sector is relation to the typical GOES-West Full Disk scan coverage.

GOES-15 Visible (0.63 µm) image showing the location of the American Samoa RSO sector in relation to the GOES-15 Full Disk scan coverage [click to enlarge]

GOES-15 Visible (0.63 µm) image showing the location of the American Samoa RSO sector in relation to the GOES-15 Full Disk scan coverage [click to enlarge]

The American Samoa RSO sector images were also successfully broadcast over the Satellite Broadcast Network (SBN) for display in AWIPS II; a sample GOES-15 Infrared (10.7 µm, 4-km resolution) image is shown below.

GOES-15 Infrared (10.7 µm) image, displayed using AWIPS II [click to enlarge]

GOES-15 Infrared (10.7 µm) image, displayed using AWIPS II [click to enlarge]

As a preview to the upcoming GOES-R series of satellites, we can examine JMA Himawari-8 Visible (0.64 µm, 0.5 km resolution) images for the same 3-hour time period, as seen below (sun glint over the open water is high during this time of day, due to the sun-satellite geometry of Himiwari-8 positioned at 140º East longitude). The images are available from the AHI instrument every 10 minutes, and show the development of organized clusters of convection just north and south of the larger islands of Samoa and Apia. Remote locations such as American Samoa will receive similar images every 5 minutes from the ABI instrument on GOES-R/S/T.

Himawari-8 Visible (0.64 µm) images [click to play animation]

Himawari-8 Visible (0.64 µm) images [click to play animation]

The nighttime glow of Hawaii’s Kilauwea volcano

April 28th, 2015
Himawari-8 3.9 µm shortwave IR images (click to play animation)

Himawari-8 3.9 µm shortwave IR images (click to play animation)

The Kilauwea Volcano on the Big Island of Hawai’i began erupting in March 2008 (blog post | USGS reference), and has been in a nearly continuous phase of activity since then. During the pre-dawn hours of 28 April 2015, thermal signatures of the Kilauwea summit lava lake and nearby lava flows could be seen on McIDAS-V images of 10-minute interval Himawari-8 3.9 µm shortwave IR images (above; click image to play animation). The dark black pixels represent the hottest IR brightness temperatures.

On the corresponding Himawari-8 2.3 µm near-IR channel images (below; click image to play animation), the clusters of bright white pixels represent the glow of the hot lava features.

Himawari-8 2.3 µm near-IR channel images (click to play animation)

Himawari-8 2.3 µm near-IR channel images (click to play animation)

A different view is provided by the polar-orbiting Suomi NPP satellite — a comparison of AWIPS II images of VIIRS 0.7 µm Day/Night Band and 3.74 µm shortwave IR data (below) revealed the locations of the hottest lava features (black to yellow to red color enhancement) at 11:40 UTC (1:40 am local time).

Suomi NPP VIIRS 0.7 µm Day/Night Band and 3.74 µm shortwave IR images

Suomi NPP VIIRS 0.7 µm Day/Night Band and 3.74 µm shortwave IR images

A longer animation using GOES-15 (GOES-West) 3.9 µm shortwave IR images (below; click image to play animation) showed considerable temporal fluctuation in the location and intensity of the hot lava pixels (black to yellow to red color enhancement). For the latest information on the Kilauea eruption, visit the Hawaiian Volcano Observatory.

GOES-15 3.9 µm shortwave IR images (click to play animation)

GOES-15 3.9 µm shortwave IR images (click to play animation)

Ice motion in the Chukchi Sea

December 9th, 2014
Suomi NPP VIIRS 0.7 µm Day/Night Band images (click to play animation)

Suomi NPP VIIRS 0.7 µm Day/Night Band images (click to play animation)

AWIPS II images of Suomi NPP VIIRS 0.7 µm Day/Night Band data covering the 05 December – 09 December 2014 period (above; click image to play animation; also available as an MP4 movie file) revealed a fairly abrupt increase in the southwesterly motion of drift ice in the Chukchi Sea (off the northwest coast of Alaska), with giant ice floes beginning to break away north of Barrow (station identifier PABR) on 08 December. Although the northern half of the satellite scene saw little to no sunlight during this time, abundant illumination from the Moon (in the Waning Gibbous phase, at 82% of full) helped to demonstrate the “visible image at night” capability of the VIIRS Day/Night Band.

This change in ice motion was caused by an increase in northeasterly wind over that region, in response to a tightening pressure gradient between a 1040 hPa high pressure centered north of Siberia and a 958 hPa low pressure centered south of Kodiak Island in the Gulf of Alaska (below). The strong winds were also creating the potential for heavy freezing spray over the open waters north and south of the Bering Strait.

Suomi NPP VIIRS 0.7 µm Day/Night Band image, with surface analysis

Suomi NPP VIIRS 0.7 µm Day/Night Band image, with surface analysis

Along the northwest coast of Alaska, northeasterly winds at Point Hope (station identifier PAPO) gusted as high as 62 knots or 71 mph on 09 December (below). Not far to the north at Cape Lisburne (PALU), the peak wind gust was 39 knots or 45 mph.

Point Hope, Alaska meteorogram

Point Hope, Alaska meteorogram

October snowfall on the Big Island of Hawai’i

October 14th, 2014
GOES-15 6.5 µm water vapor channel images (click to play animation)

GOES-15 6.5 µm water vapor channel images (click to play animation)

McIDAS images of GOES-15 (GOES-West) 6.5 µm water vapor channel data (above; click image to play animation) showed an upper-level low that moved from east to west over the Hawaiian Islands during the 13 October – 14 October 2014 period. This low forced the development of widespread showers and thunderstorms, especially over the Big Island of Hawai’i — and even produced some snowfall in the highest elevations around the summits of Mauna Kea and Mauna Loa. Some excerpts from Area Forecast Discussions issued by the National Weather Service at Honolulu on 13 October:

FXHW60 PHFO 131350
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST MON OCT 13 2014
[…]
FORECAST MODELS HAVE BEEN CONSISTENTLY CALLING FOR 500 MB TEMPERATURES BETWEEN -12 AND -13C WITHIN THE CORE OF THE COMPACT UPPER LOW. THIS IS EXCEPTIONALLY COLD FOR OCTOBER
[…]
FORECAST MODELS SHOW THAT THIS FEATURE WILL HOLD AS IT MOVES OVER THE BIG ISLAND LATER TODAY INTO TONIGHT…LIKELY PRODUCING ACCUMULATING SNOW OVER THE SUMMITS ABOVE 12000 FT. AS A RESULT…A WINTER WEATHER ADVISORY HAS BEEN ISSUED.
[…]

=====

FXHW60 PHFO 140152
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
330 PM HST MON OCT 13 2014
[…]
THE SUMMITS OF THE BIG ISLAND HAVE BEGUN TO REPORT SNOWFALL ACCUMULATION…AND THIS WILL CONTINUE WITH A COUPLE OF INCHES POSSIBLE OVERNIGHT.
[…]

While examining a nighttime (11:21 UTC or 1:21 am local time) comparison of AWIPS II images of Suomi NPP VIIRS 0.7 µm Day/Night Band (DNB) and 11.45 µm IR channel data covering Tropical Storm Ana (below), the main feature of interest was the inner core of cloud-top IR brightness temperatures as cold as -86º C (yellow color enhancement) associated with Ana — however, equally interesting was the appearance of a pair of bright white features in the middle of the Big Island on the DNB image (which highlighted the areas of snow cover that remained at the higher elevations).

Suomi NPP VIIRS 0.7 µm Day/Night Band and 11.45 µm IR channel images

Suomi NPP VIIRS 0.7 µm Day/Night Band and 11.45 µm IR channel images

A closer view comparing the VIIRS DNB and IR images centered over the Big Island (below) seemed to suggest that the 2 patches of bright snow cover (well-illuminated by a nearly Full Moon) were located along the western slopes of Mauna Kea and Mauna Loa. A similar comparison of the DNB image and high-resolution topography can be seen here.

Suomi NPP VIIRS 0.7 µm Day/Night Band and 11.45 µm IR channel images

Suomi NPP VIIRS 0.7 µm Day/Night Band and 11.45 µm IR channel images

An animation of GOES-15 0.63 µm visible channel images during the following daylight hours of 14 October (below; click image to play animation) revealed the gradual melting of the 2 patches of high-elevation snow cover as temperatures rose from around freezing into the 50s F near the summits (Cooperative observations).

GOES-15 0.63 µm visible channel images (click to play animation)

GOES-15 0.63 µm visible channel images (click to play animation)