Friday, July 7, 2017

Satellite Perspective on Arctic Lightning

In yesterday's post on lightning over the Beaufort Sea I somehow neglected to look at the satellite imagery to confirm the presence of deep convective storms in the region where lightning was reported.  I realized this oversight when Rick Thoman sent me an image last night - thanks Rick!  After digging around on the UAF Geographic Information Network of Alaska (GINA) website, I found several images that clearly show the evolution of the thunderstorms.

Here's a particularly nice photo showing a curved line of storms in approximately the center of the image; the shadow of the deep cumulonimbus clouds is evident to the north of the line (the sun's position is in the southeast at the time of this shot).  For reference, Point Barrow is visible in the center left of the image, and Banks Island is towards the upper right.


Here's a zoomed-in photo.


In the image sequence below I've paired up a selection of satellite views with the lightning reports from approximately the same time, running from about 2am to 1pm AKST on Monday; the lightning strikes clearly correspond to the brightest (deepest and therefore most reflective) storm clouds.

















2 comments:

  1. Very nice. An earlier post noted that these t-storms coincided with ice-free ocean, but maybe there's a positive feedback where the energetic t-storm winds disperse sea ice? I wonder, are t-storms becoming more widespread in the Arctic Ocean? How far north does the GOES-16 lightning detector sense?

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  2. I imagine that thunderstorms are becoming more common over parts of the Arctic Ocean that now have a longer ice-free season, although I can't point to data showing this. But I doubt there is a significant wind/ice feedback as thunderstorm winds would tend to be short-lived and in any case very infrequent.

    Apparently the GOES-16 lightning mapper will operate only up to 52°N

    http://www.goes-r.gov/spacesegment/glm.html

    There have been some satellite instruments that have detected lightning globally for various missions but I'm not aware of any current or long-term global monitoring data.

    Perhaps the best way to tackle the problem would be to look at weather observations from Arctic sites. For example Barrow has reported thunder 3 times in 2013-2017 (one just a couple of weeks ago) which is a higher frequency than the long-term average.

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