First images from Himawari-8

December 18th, 2014
Himawari-8 0.64 µm visible channel image (click to enlage)

Himawari-8 0.64 µm visible channel image (click to enlarge)

The Japan Meteorological Agency has released the first images from the AHI instrument on the Himawari-8 satellite, which was launched on 7 October this year.

This link shows full disk imagery from all 16 spectral bands. The AHI on Himawari-8 is very similar to the ABI that will fly on GOES-R.

A comparison of images using each of the 16 spectral bands is shown below, centered over the Sea of Japan. Cloud streets are seen over much of the open waters, due to the southeastward and eastward transport of very cold air from Siberia (surface analysis). Lee waves (or “mountain waves”) are evident on the water vapor bands (8, 9  and 10) downwind or southeast of the higher terrain areas on the main Japanese island of Honshu.

Comparison of the 16 AHI spectral bands, centered on the Sea of Japan (click to enlarge)

Comparison of the 16 AHI spectral bands, centered on the Sea of Japan (click to enlarge)

 Band 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
µm  0.47   0.64   0.86   1.37   1.6   2.2   3.9   6.2   7.0   7.4   8.4   9.6   10.33   11.2   12.3   13.3 

Similar comparisons of Himawari-8 images covering Hawaii, western Australia, and the far Southern Hemisphere are available on the First Light AHI Satellite Band Webapp.

As seen on the MTSAT-2 vs Himawari-8 comparison below, even at large satellite viewing angles over the far southern portion of the Southern Hemisphere (for example, between Australia/Tasmania and Antarctica) AHI imagery such as that from water vapor channels exhibits higher quality (due to factors such as improved spatial resolution, signal-to-noise ratio, data bit depth, etc).

MTSAT-2 vs Himawari-8 water vapor channel images

MTSAT-2 vs Himawari-8 water vapor channel images

Rapid cyclogenesis off the coast of Japan, with an aircraft experiencing severe turbulence

December 16th, 2014
COMS-1 6.95 µm water vapor channel images (click to play animation)

COMS-1 6.95 µm water vapor channel images (click to play animation)

McIDAS images of KARI COMS-1 6.95 µm water vapor channel data (above; click image to play animation; also available as an MP4 movie file) showed the tell-tale signatures — well-formed dry slot; distinct comma head — of rapid cyclogenesis for a pair of storms off the west and east coasts of Japan on 16 December 2014. An American Airlines passenger jet flying from Seoul, South Korea (RKSO) to Dallas/Fort Worth, Texas experienced severe turbulence at an altitude around 27,000 feet over the eastern portion of Honshu Island, Japan (media report); several passengers and crew members were injured (with some requiring hospitalization), forcing the aircraft to divert from its course and turn back to make a landing at Tokyo Narita airport (RJAA). The turbulence encounter likely occurred near the center portion of the red square which was drawn on the images whose times were within about 30 minutes of the 10:35 UTC turbulence encounter  (FlightAware track log) — note the development of a “transverse banding” signature along the western edge of the southern storm comma head feature (10:00 UTC image).  After the multi-layered clouds of the comma head departed, lee waves or “mountain waves” could be seen downwind of the high terrain of Honshu Island. It should also be noted that the flight path was in the left exit region of an intensifying upper-tropospheric jet streak (250 hPa winds).

A dry slot exhibiting much warmer brightness temperatures (brighter yellow to orange color enhancement) was seen with the more southern of the two storms, which became the dominant system as it moved northeastward and rapidly intensified from a central pressure of 998 hPa at 06 UTC to 971 hPa at 18 UTC (below). The storm was forecast to produce a large area of hurricane-force winds over the far northwestern Pacific Ocean.

MTSAT-2 6.75 µm water vapor channel images with surface analyses at 06, 12, and 18 UTC

MTSAT-2 6.75 µm water vapor channel images with surface analyses at 06, 12, and 18 UTC

An AWIPS image of MTSAT-2 water vapor channel data with overlays of the NWS Ocean Prediction Center surface analysis and Metop ASCAT scatterometer winds showed surface wind speeds as high as 55 knots (63 mph) with the southern storm and 53 knots (61 mph) with the northern storm at 11:48 UTC (below). During the day wind gusts as high as 81 knots (93 mph) were reported at the Izu Islands south of Tokyo Bay.

MTSAT-2 6.75 µm water vapor channel image, with Metop ASCAT scatterometer surface winds and surface analysis

MTSAT-2 6.75 µm water vapor channel image, with Metop ASCAT scatterometer surface winds and surface analysis

Aircraft dissipation trails and “hole punch clouds” over Florida

December 12th, 2014
GOES-13 0.63 µm visible channel images (click to play animation)

GOES-13 0.63 µm visible channel images (click to play animation)

McIDAS images of 1-km resolution GOES-13 0.63 µm visible channel data (below; click image to play animation; also available as an MP4 movie) revealed numerous aircraft dissipation trails and “hole punch clouds” which formed over southern Florida and the adjacent waters of the Atlantic Ocean on 12 December 2014. These features are formed when an aircraft penetrates a supercooled cloud layer — the particles in the exhaust act as ice nuclei which allow the supercooled water droplets to transform into ice crystals.

A comparison of 250-meter resolution Terra MODIS true-color and false-color Red/GreenBlue (RGB) images from the SSEC MODIS Today site (below) confirmed that the clouds within the dissipation trails and the hole punch features had glaciated — ice crystal clouds appear as shades of cyan in the false-color image, in contrast to supercooled water droplet cloud which appear as varying shades of white.

Terra MODIS true-color and false-color images

Terra MODIS true-color and false-color images

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