![\"Himawari-8](\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2018\/12\/181222_himawari8_infrared_Krakatoa_anim.gif\")
<\/a>Himawari-8 “Clean” Infrared Window (10.4 \u00b5m)<\/em> images, with hourly plots of surface reports from Jakarta (station identifier WIII)<\/em> [click to play animation | MP4<\/strong><\/a>]<\/p><\/div>Himawari-8 “Clean” Infrared Window (10.4 \u00b5m) images (above)<\/strong><\/em> showed the volcanic cloud from an eruption of Anak Krakatau<\/strong><\/a> in Indonesia on 22 December 2018. Two distinct pulses were evident: the first began around 1340 UTC, with the second starting around 1520 UTC. At times the cloud-top infrared brightness temperatures were -80\u00baC or colder (violet enhancement)<\/em> — which roughly corresponded to altitudes around 15-16 km on rawinsonde data<\/strong><\/a> from nearby Jakarta (WIII) (below)<\/strong><\/em>. The eruption process appears to have played a role in generating a tsunami<\/strong><\/a> that was responsible for over 400 fatalities — via a partial collapse of the southern flank of the volcano which then triggered an undersea landslide (visualization<\/a><\/strong>).<\/p>\n Plots of rawinsonde data from Jakarta, Indonesia [click to enlarge]<\/p><\/div>After sunrise, the volcanic cloud was evident in Himawari-8 “Red” Visible (0.64 \u00b5m) images (below)<\/strong><\/em> — a toggle between Visible and Infrared images at 0110 UTC<\/strong><\/a> showed an example of one of the cold overshooting tops.<\/p>\n Himawari-8 “Red” Visible (0.64 \u00b5m)<\/em> images, with hourly plots of surface reports\u00a0from Jakarta (station identifier WIII)<\/em> [click to play animation | MP4<\/strong><\/a>]<\/p><\/div>At the onset of the eruption, multi-spectral retrievals from the NOAA\/CIMSS Volcanic Cloud Monitoring<\/strong><\/a> site showed Ash Height values of 12-14 km and Ash Loading values of 9-10 g\/m2 (below)<\/em><\/strong>. However, after about 1.5 hours the extremely high water and ice content of the volcanic cloud prevented further retrievals of such parameters.<\/p>\n Himawari-8 Ash Height retrievals [click to play animation]<\/p><\/div> Himawari-8 Ash Loading retrievals [click to play animation]<\/p><\/div>A toggle between NOAA-20 VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 \u00b5m) images viewed using RealEarth<\/strong><\/a> (below)<\/strong><\/em> showed the volcanic cloud at 0610 UTC on 23 December.<\/p>\n NOAA-20 VIIRS True Color RGB and Infrared Window (11.45 \u00b5m)<\/em> images at 0610 UTC [click to enlarge]<\/p><\/div>A comparison of Infrared Window images from NOAA-20 VIIRS (11.45 \u00b5m) and Himawari-8 AHI (10.4 \u00b5m) at 0610 UTC (below)<\/strong><\/em> demonstrated the advantage of improved spatial resolution — the minimum cloud-top infrared brightness temperature of the overshooting top feature was significantly colder on the 375-m resolution VIIRS image (-87\u00baC, darker shade of violet) than on the corresponding AHI image with 2-km resolution at satellite sub-point (-74.2\u00baC).<\/p>\n 0610 UTC Infrared Window images from NOAA-20 VIIRS (11.45 \u00b5m)<\/em> and Himawari-8 AHI (10.4 \u00b5m)<\/em> [click to enlarge]<\/p><\/div>There was also a significant amount of lightning associated with this volcanic cloud: #Krakatoa<\/a>\/#Krakatau<\/a> #lightning<\/a> update: Rough counts have had peak values of 90 lightning events per minute detected around the volcano! Between ~1430 UTC 22 Dec and ~1900 UTC 23 Dec, there have been tens of thousands of lightning events detected by GLD360. pic.twitter.com\/iekphVjsD2<\/a><\/p>\n \u2014 Chris Vagasky (@COweatherman) December 23, 2018<\/a><\/p><\/blockquote>\n<\/a><\/a><\/a><\/a><\/a><\/a>
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