Suomi NPP Day/Night Band (0.70 µm) and Infrared Window Channel (11.45 µm) images at 1616 UTC on 8 July 2015 (click to enlarge)

The toggle above shows Suomi NPP VIIRS 0.7 µm Day/Night Band and the 11.45 µm Infrared images (courtesy of William Straka, SSEC). It is unusual because two strong tropical cyclones (Category 2 Typhoon Chan-Hom on the left, and Category 4 Typhoon Nangka on the right) are captured in one satellite overpass.

The Day/Night Band (DNB) image shows little evidence of lightning (bright white streaks) with either storm; due to ample illumination from a Third Quarter Moon (at 54% of Full),  the DNB was able to provide a “visible image at night”. Both images show Nangka to be the stronger storm: the eye is more pronounced, and is more symmetric. More information on these storms is available here.

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Himawari-8 6.2 µm (top), 6.9 µm (middle) and 7.3 µm (bottom) water vapor infrared imagery, 0000 UTC 5 July 2015 – 1200 UTC 7 July 2015 (click to animate)

The Japanese Meteorological Agency is using Himawari-8 as its operational satellite, effective 0200 UTC on 7 July 2015. The animation above shows two days of water vapor imagery from Himawari-8 (6.2 µm, top, 6.9 µm, middle and 7.3 µm, bottom) over the tropical Pacific, revealing the train of three tropical cyclones moving westward towards Asia (testimony to why satellite data are important!). Typhoon Nangka, on the right, has developed an eye. Himawari-8 samples a full-disk image every 10 minutes, with nominal 2-km resolution in the infrared channels. Moveable sectors are also available at 2.5-minute intervals, such as shown in this animation from here.

Himawari-8 has 0.5-km resolution in the 0.64 µm visible channel. A 3-hour animation over Typhoon Nangka, at routine 10-minute time-steps, is shown below.

Himawari-8 0.64 µm visible imagery, 0400 UTC 5 July 2015 – 0700 UTC 7 July 2015, showing Typhoon Nangka (click to animate)

The sixteen channels on the AHI instrument onboard Himawari-8 are similar to those that will be found on the ABI instrument onboard GOES-R, which is scheduled for launch in March of 2016. The animation below shows all 16 channels of the Himawari-8 AHI.

Himawari-8 data, all AHI channels, over Typhoon Nangka, 0400 UTC 5 July 2015 – 0810 UTC 7 July 2015 (click to animate)

A very large (74 MegaByte) Himawari-8 true-color Red/Green/Blue (RGB) full-disk image at 0340 UTC is shown below (courtesy of Jerrold Robaidek, SSEC).

Himawari-8 true-color image

A few interesting features to point out on the full-disk image are shown below (courtesy of Scott Bachmeier, CIMSS) — from north to south:

Wildfire smoke and thunderstorms in Siberia

Smoke from fires in Alaska and Canada

Blowing dust/sand in the Gobi Desert, and air pollution in northeastern China

Mountain waves downwind of Japan, and developing storms in the North Pacific Ocean

Tropical Storm Linfa off the coast of China

Typhoons Chan-Hom and Nangka in the West Pacific Ocean

Thunderstorms over the Indian Ocean

Banded thunderstorms over northern New Zealand, and snow cover in the mountains of southern New Zealand

Winter storm along the coast of Antarctica

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Himawari-8 10.35 µm infrared imagery, 1447-2002 UTC on 6 July 2015 (click to animate)

Typhoon Chan-Hom in the western Pacific Ocean is forecast to strengthen and move towards Taiwan later this week. A Himawari-8 target sector is viewing the storm today, and a 5-hour animation with a 2.5-minute time step (10.35 µm infrared imagery) is shown above. Very cold overshooting tops (the yellow enhancement show tops colder than -90º C) periodically develop. The toggle below of Sea Surface Temperature and Wind Shear (taken from the CIMSS Tropical Cyclones site) shows conditions — very warm sea-surface temperatures and low values of deep-layer wind shear — favorable for strengthening.

SSTs and Wind Shear superimposed on the forecast track of Typhoon Chan-Hom (click to enlarge)

The three water vapor images shown below, also from Himawari-8, show that Chan-Hom is the 2nd of three tropical systems in a row. Linfa is west of the Philippines and approaching the coast of China; Nangka is east of Chan-Hom. Note that the 6.2 µm imagery is more sensitive to water vapor higher in the troposphere: Cirrus shields are apparent. The 7.3 µm imagery is not so sensitive to upper-level moisture and can therefore detect cumulus fields underneath cirrus.

Himawari-8 6.2 µm, 6.9 µm and 7.3 µm infrared water vapor images, 2040 UTC on 6 July 2015 (click to enlarge)

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Suomi NPP VIIRS 0.70 µm visible Day/Night Band and 11.45 µm – 3.74 µm IR Brightness Temperature Difference images, and Ceilings and Visibilities, ~0800 UTC (click to enlarge)

July’s first Full Moon occurred at 0219 UTC on 2 July (a second full moon occurs later this month on 31 July). Strong illumination from the moon showed river valley fog in several tributaries of the Mississippi River (for example, the Wisconsin River in southwest Wisconsin; the Upper Iowa River in Iowa) across the Upper Midwest. The Suomi NPP VIIRS Day/Night Band also shows a plume of Canadian wildfire smoke aloft, stretching from central Iowa northwestward to western Minnesota. This smoke (visible on 1 July in Aqua true-color imagery from the MODIS Today site) is not apparent in the IR Brightness Temperature Difference field, although the river valley fog certainly is. Smoke is transparent to most infrared channels and detection at night is very difficult if visible information such as that provided by the Day/Night Band is not present.

The VIIRS Day/Night Band also enabled detection of the dense plume of Canadian wildfire smoke as it moved off the US East Coast and over the adjacent offshore waters of the western Atlantic Ocean at 0614 UTC  (below). Again, note that the smoke aloft does not exhibit a signature on the corresponding VIIRS Infrared imagery.

Suomi NPP VIIRS 0.7 µm Day/Night Band and 11.45 µm Infrared images (click to enlarge)

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