{"id":28541,"date":"2018-06-18T18:54:17","date_gmt":"2018-06-18T18:54:17","guid":{"rendered":"http:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=28541"},"modified":"2018-06-19T22:54:23","modified_gmt":"2018-06-19T22:54:23","slug":"high-cloud-shadow-over-eastern-iowa","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/28541","title":{"rendered":"High cloud shadow over eastern Iowa"},"content":{"rendered":"<p><center><\/p>\n<blockquote class=\"twitter-tweet\" data-lang=\"en\">\n<p dir=\"ltr\" lang=\"en\"><a href=\"https:\/\/twitter.com\/CIMSS_Satellite?ref_src=twsrc%5Etfw\">@CIMSS_Satellite<\/a>: Any idea what the relatively small, darker area\/depression was going over Grundy County (west of Waterloo) from 1232z to 1342z? Most prevalent at 1312z. Shows up in all GOES bands. Channel 7 also shows a corresponding darker area just north of that area.<\/p>\n<p>\u2014 Andrew Ansorge (@ajsorge) <a href=\"https:\/\/twitter.com\/ajsorge\/status\/1008707662832381952?ref_src=twsrc%5Etfw\">June 18, 2018<\/a><\/p><\/blockquote>\n<p><script async src=\"https:\/\/platform.twitter.com\/widgets.js\" charset=\"utf-8\"><\/script><\/center><\/p>\n<p>It&#8217;s always good to get a question that lends itself well to the &#8220;<strong><a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/category\/what-the-heck-is-this\">What the heck is this?<\/a><\/strong>&#8221; blog category. The answer, as is often the case, relies on an examination of imagery from a variety of GOES-16 <strong><a href=\"https:\/\/www.goes-r.gov\/spacesegment\/abi.html\">ABI<\/a><\/strong> bands.\u00a0 To begin, note the darker feature seen on 1-minute <strong><a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/23225\">Mesoscale Domain Sector<\/a><\/strong> GOES-16 &#8220;Blue&#8221; Visible (<a href=\"http:\/\/cimss.ssec.wisc.edu\/goes\/OCLOFactSheetPDFs\/ABIQuickGuide_Band01.pdf\"><strong>0.47 \u00b5m<\/strong><\/a>), &#8220;Red&#8221; Visible (<a href=\"http:\/\/cimss.ssec.wisc.edu\/goes\/OCLOFactSheetPDFs\/ABIQuickGuide_Band02.pdf\"><strong>0.64 \u00b5m<\/strong><\/a>) and Near-Infrared &#8220;Vegetation&#8221; (<a href=\"http:\/\/cimss.ssec.wisc.edu\/goes\/OCLOFactSheetPDFs\/ABIQuickGuide_Band03.pdf\"><strong>0.86 \u00b5m<\/strong><\/a>) images <em><strong>(below),<\/strong><\/em> which was moving northeastward across eastern Iowa and passing just to the west of Waterloo (KALO) on the morning of <strong><a href=\"http:\/\/www.wpc.ncep.noaa.gov\/dailywxmap\/index_20180618.html\">18 June 2018<\/a><\/strong>.<\/p>\n<p><div style=\"width: 650px\" class=\"wp-caption aligncenter\"><a class=\"thumbnail\" href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2018\/06\/180618_goes16_visible_nearIR_Iowa_high_cloud_shadow_anim.gif\"><img loading=\"lazy\" decoding=\"async\" class=\"thumbnail\" src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2018\/06\/G16_VIS_NEARIR_IA_18JUN2018_960x427_B123_2018169_130101_0003PANELS_00032.GIF\" alt=\"GOES-16 &quot;Blue&quot; Visible (0.47 \u00b5m), &quot;Red&quot; Visible (0.64 \u00b5m) and Near-Infrared &quot;Snow\/Ice&quot; (1.61 \u00b5m) images\" width=\"640\" height=\"480\" \/><\/a><p class=\"wp-caption-text\">GOES-16 &#8220;Blue&#8221; Visible <em>(0.47 \u00b5m, left)<\/em>, &#8220;Red&#8221; Visible <em>(0.64 \u00b5m, center)<\/em> and Near-Infrared &#8220;Vegetation&#8221; <em>(0.86 \u00b5m, right)<\/em> images [click to play animation | <a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2018\/06\/180618_goes16_visible_nearIR_Iowa_high_cloud_shadow_anim.mp4\"><strong>MP4<\/strong><\/a>]<\/p><\/div>To explore the initial hypothesis that this might be a shadow from a higher-altitude cloud feature, GOES-16 Near-Infrared &#8220;Cirrus&#8221; (<strong><a href=\"http:\/\/cimss.ssec.wisc.edu\/goes\/OCLOFactSheetPDFs\/ABIQuickGuide_Band04.pdf\">1.37 \u00b5m<\/a><\/strong>), Mid-level Water Vapor (<a href=\"http:\/\/cimss.ssec.wisc.edu\/goes\/OCLOFactSheetPDFs\/ABIQuickGuide_Band09.pdf\"><strong>6.9 \u00b5m<\/strong><\/a>) and Upper-level Water Vapor (<a href=\"http:\/\/cimss.ssec.wisc.edu\/goes\/OCLOFactSheetPDFs\/ABIQuickGuide_Band08.pdf\"><strong>6.2 \u00b5m<\/strong><\/a>) images were examined <em><strong>(below),<\/strong><\/em> which did indeed reveal a small cloud element aloft that was drifting in the same direction as the darker feature seen above.<\/p>\n<p><div style=\"width: 650px\" class=\"wp-caption aligncenter\"><a class=\"thumbnail\" href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2018\/06\/180618_goes16_cirrus_water_vapor_Iowa_high_cloud_shadow_anim.gif\"><img loading=\"lazy\" decoding=\"async\" class=\"thumbnail\" src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2018\/06\/G16_CIRRUS_WATER_VAPOR_IA_18JUN2018_960x427_B498_2018169_130101_0003PANELS_00032.GIF\" alt=\"GOES-16 Near-Infrared \" width=\"640\" height=\"480\" \/><\/a><p class=\"wp-caption-text\">GOES-16 Near-Infrared &#8220;Cirrus&#8221;<em> (1.37 \u00b5m, left),<\/em> Mid-level Water Vapor <em>(6.9 \u00b5m, center)<\/em> and Upper-level Water Vapor <em>(6.2 \u00b5m, right)<\/em> images [click to play animation | <a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2018\/06\/180618_goes16_cirrus_water_vapor_Iowa_high_cloud_shadow_anim.mp4\"><strong>MP4<\/strong><\/a>]<\/p><\/div>Finally, a comparison of GOES-16 Near-Infrared &#8220;Cirrus&#8221; (1.37 \u00b5m), Shortwave Infrared (<a href=\"http:\/\/cimss.ssec.wisc.edu\/goes\/OCLOFactSheetPDFs\/ABIQuickGuide_Band07.pdf\"><strong>3.9 \u00b5m<\/strong><\/a>) and &#8220;Clean&#8221; Infrared Window (<a href=\"http:\/\/cimss.ssec.wisc.edu\/goes\/OCLOFactSheetPDFs\/ABIQuickGuide_Band13.pdf\"><strong>10.3 \u00b5m<\/strong><\/a>) images <em><strong>(below)<\/strong> <\/em>showed that this small (and likely thin) high-altitude cloud exhibited no signature in the Shortwave Infrared, but did exhibit a 10.3 \u00b5m brightness temperature as cold as -20\u00baC <em>(cyan enhancement)<\/em> at times.<\/p>\n<p><div style=\"width: 650px\" class=\"wp-caption aligncenter\"><a class=\"thumbnail\" href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2018\/06\/180618_goes16_cirrus_shortwaveIR_IRwindow_Iowa_high_cloud_shadow_anim.gif\"><img loading=\"lazy\" decoding=\"async\" class=\"thumbnail\" src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2018\/06\/G16_CIRRUS_SWIR_IR_IA_18JUN2018_960x427_B4713_2018169_130101_0003PANELS_00032.GIF\" alt=\"GOES-16 Near-Infrared \" width=\"640\" height=\"480\" \/><\/a><p class=\"wp-caption-text\">GOES-16 Near-Infrared &#8220;Cirrus&#8221;<em> (1.37 \u00b5m, left),<\/em> Shortwave Infrared<em> (3.9 \u00b5m, center)<\/em> and &#8220;Clean&#8221; Infrared Window<em> (10.3 \u00b5m, right)<\/em> images [click to play animation | <a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2018\/06\/180618_goes16_cirrus_shortwaveIR_IRwindow_Iowa_high_cloud_shadow_anim.mp4\"><strong>MP4<\/strong><\/a>]<\/p><\/div>12 UTC rawinsonde data from Davenport, Iowa <em><strong>(below)<\/strong><\/em> showed southwesterly winds and an air temperature just below -20\u00baC at an altitude of around 9.6 km.<\/p>\n<p><div style=\"width: 650px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2018\/06\/180618_12UTC_KDVN_RAOB.GIF\"><img loading=\"lazy\" decoding=\"async\" class=\"\" src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2018\/06\/180618_12UTC_KDVN_RAOB.GIF\" alt=\"12 UTC rawinsonde data from Davenport, Iowa [click to enlarge]\" width=\"640\" height=\"480\" \/><\/a><p class=\"wp-caption-text\">12 UTC rawinsonde data from Davenport, Iowa [click to enlarge]<\/p><\/div>Thanks to Andrew Ansorge (NWS DMX) and Rich Mamrosh (NWS GRB) for alerting us to this interesting feature!<\/p>\n","protected":false},"excerpt":{"rendered":"<p>@CIMSS_Satellite: Any idea what the relatively small, darker area\/depression was going over Grundy County (west of Waterloo) from 1232z to 1342z? Most prevalent at 1312z. Shows up in all GOES bands. Channel 7 also shows a corresponding darker area just north of that area. \u2014 Andrew Ansorge (@ajsorge) June 18, 2018 It&#8217;s always good to [&hellip;]<\/p>\n","protected":false},"author":18,"featured_media":28561,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[74,38],"tags":[],"class_list":["post-28541","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-goes-16","category-what-the-heck-is-this"],"acf":[],"_links":{"self":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/28541","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=28541"}],"version-history":[{"count":18,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/28541\/revisions"}],"predecessor-version":[{"id":28586,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/28541\/revisions\/28586"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media\/28561"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=28541"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=28541"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=28541"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}