{"id":424,"date":"2007-06-19T22:37:59","date_gmt":"2007-06-19T22:37:59","guid":{"rendered":"http:\/\/cimss.ssec.wisc.edu\/satellite-blog\/2007\/06\/19\/enhanced-v-and-warm-trench-ir-signatures\/"},"modified":"2008-03-11T20:51:36","modified_gmt":"2008-03-11T20:51:36","slug":"enhanced-v-and-warm-trench-ir-signatures","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/424","title":{"rendered":"“Enhanced-V” and “Warm Trench” IR signatures"},"content":{"rendered":"

\"AWIPS<\/a><\/p>\n

Severe thunderstorms developed over northwestern Kansas on 19 June 2007<\/strong><\/a>. An AWIPS image of the MODIS 11.0\u00c2\u00b5m InfraRed (IR) channel (above)<\/strong><\/em> revealed an “enhanced-v”<\/strong> and a “warm trench”<\/strong> IR signature on adjacent storm tops. The coldest cloud top brightness temperature values were -77\u00c2\u00ba C<\/strong> on both signatures; the warmest IR temperature associated with the “enhanced-v” was -58\u00c2\u00ba C<\/strong>, while the warmest IR temperature in the “warm trench” was –61\u00c2\u00ba C<\/strong>. You can get a sense that such a “trench” can surround an overshooting top by examining astronaut photography of thunderstorms taken from the space shuttle<\/strong><\/a> (image courtesy of Earth Sciences and Image Analysis Laboratory, NASA Johnson Space Center).<\/em><\/p>\n

\"AWIPS<\/a><\/p>\n

A closer view of the MODIS IR image with a different color enhancement (above)<\/strong><\/em> shows that both IR signatures were surrounded by clusters of negative (yellow)<\/em> and positive (red)<\/em> cloud-to-ground (CG) lightning strikes. SPC storm reports<\/strong><\/a> listed hail<\/strong><\/a> (up to 1.75 inches in diameter)<\/em> within 1 hour of the MODIS image in the region of both IR signatures, but only the southernmost enhanced-v storm produced a tornado<\/strong><\/a>; however, higher radar reflectivity values<\/strong><\/a> (65-70 dBz) were seen with the northernmost “warm trench” storm.<\/p>\n

\"AWIPS<\/a><\/p>\n

A comparison of the GOES-12 and MODIS IR images (above)<\/strong><\/em> demonstrates the better detection capability of these types of IR signatures using 1-km resolution MODIS IR imagery (vs 4-km resolution GOES IR imagery). The IR channels on the next-generation GOES-R Advanced Baseline Imager (ABI)<\/strong><\/a> will have a 2-km resolution.<\/p>\n

\"GOES-12<\/a><\/p>\n

GOES-12 10.7\u00c2\u00b5m IR imagery (above; 100-image QuickTime animation<\/a>)<\/strong><\/em> showed that these severe thunderstorms in Kansas persisted into the nighttime hours, and eventually became part of a very large Mesoscale Convective Complex (MCC) farther to the south over Oklahoma and Texas. Note the large number of IR pixels exhibiting brightness temperatures of -80\u00c2\u00ba C<\/strong> or colder (violet enhancement)<\/em> after 02:02 UTC; IR brightness temperatures were as cold as -93\u00c2\u00ba C<\/strong> on a 23:22 UTC NOAA-12 AVHRR IR image<\/strong><\/a>, and as cold as -84\u00c2\u00ba C<\/strong> on 05:10\/05:13 UTC GOES \/ MODIS IR images<\/strong><\/a> (with 4159 negative<\/strong><\/a> and 334 positive<\/strong><\/a> CG lightning strikes at that time). Later SPC storm reports<\/strong><\/a> included hail up to 4.25 inches<\/strong> in diameter in Kansas (at around 00:05 UTC), and wind gusts to 94 mph<\/strong> in Texas (at around 07:09 UTC).<\/p>\n","protected":false},"excerpt":{"rendered":"

Severe thunderstorms developed over northwestern Kansas on 19 June 2007. An AWIPS image of the MODIS 11.0\u00c2\u00b5m InfraRed (IR) channel (above) revealed an “enhanced-v” and a “warm trench” IR signature on adjacent storm tops. The coldest cloud top brightness temperature values were -77\u00c2\u00ba C on both signatures; the warmest IR temperature associated with the “enhanced-v” […]<\/p>\n","protected":false},"author":18,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[19,34,30,12,3],"tags":[],"class_list":["post-424","post","type-post","status-publish","format-standard","hentry","category-goes-12","category-goes-r","category-lightning","category-modis","category-severe-convection"],"acf":[],"_links":{"self":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/424","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/users\/18"}],"replies":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/comments?post=424"}],"version-history":[{"count":0,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/424\/revisions"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=424"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=424"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=424"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}