Himawari-8 Water Vapor Imagery

March 25th, 2015 |
Himawari-8 6.2 µm infrared water vapor channel images (click to play animation)

Himawari-8 6.2 µm infrared water vapor channel images (click to play animation)

Full-resolution animations of Himawari-8 6.2 µm water vapor imagery suggest what a gamechanger Himawari-8 data is, and what a gamechanger GOES-R data will be. Full-disk imagery at every 10 minutes, and at 2-km resolution, means atmospheric motion vectors computed from water vapor imagery (or other channels, such as the 10.35 µm) will cover a larger area and be far more accurate than with present GOES (or MTSAT).

In addition, because there are multiple water vapor channels on Himawari-8 (as will be on GOES-R), water vapor at different levels in the atmosphere can be tracked easily. In the animation below, low-level cloud streets between Japan and the large storm over the northern Pacific are clearly evident, whereas they are shielded from view in the animation above by high-level cirrus — although their presence is evident once they emerge from under the cirrus. Weighting Functions for two similar channels on the GOES Sounder (from here) show that the shorter-wavelength 6.2µm channel will have a larger response to upper level moisture; the longer-wavelength 7.3 µm channel will have a larger response to lower level moisture. Interactions with land features that are evident in the 7.3 µm imagery below do not show up in the 6.2 µm imagery above because most of the signal at 6.2µm is emitted from the upper troposphere. Combining the three water vapor channels (there is also a 6.9 µm channel, not shown here) gives an excellent three-dimensional representation of water vapor in the atmosphere at high temporal resolution.

Himawari-8 7.3 µm infrared water vapor channel images (click to play animation)

Himawari-8 7.3 µm infrared water vapor channel images (click to play animation)

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