{"id":3457,"date":"2009-09-18T22:41:22","date_gmt":"2009-09-18T22:41:22","guid":{"rendered":"http:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=3457"},"modified":"2009-09-21T16:51:57","modified_gmt":"2009-09-21T16:51:57","slug":"mtsat-1r-band-5-anomaly","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/3457","title":{"rendered":"MTSAT-1R Band 5 Anomaly"},"content":{"rendered":"<p style=\"text-align: center;\">\n<div style=\"width: 490px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2009\/09\/MTSAT_2009259_1430_GHOST_HURRICANEEYE-1.GIF\" target=\"_blank\"><img loading=\"lazy\" decoding=\"async\" class=\"    \" title=\"Night-time MTSAT-1R 3.75 \u00c2\u00b5m shortwave IR image (14:30 UTC)\" src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2009\/09\/MTSAT_2009259_1430_GHOST_HURRICANEEYE-1.GIF\" alt=\"MTSAT-1R shortwave IR image\" width=\"480\" height=\"385\" \/><\/a><p class=\"wp-caption-text\">Night-time MTSAT-1R 3.75 \u00c2\u00b5m shortwave IR image (14:30 UTC)<\/p><\/div>\n<p>A curious image artifact was noted on MTSAT-1R 3.75 \u00c2\u00b5m shortwave IR imagery, in the form of a very cold &#8220;false eye&#8221; appearing\u00c2\u00a0 just to the right of the actual eye of Typhoon Choi-Wan (17W) in the western North Pacific Ocean<strong> <\/strong>. The &#8220;ghost&#8221; of the eye exhibited a satellite radiance of zero <em>(very cold, appearing bright white on the image),<\/em> and was offset from the true eye by 16 pixels in the horizontal and 1-2 pixels in the vertical. This false eye was most apparent on MTSAT-1R imagery during the local night-time hours, as was seen on 16 September 2009 at 14:30 UTC <em><strong>(above)<\/strong><\/em> and 15:30 UTC <em><strong>(below)<\/strong><\/em>.<\/p>\n<p style=\"text-align: center;\">\n<div style=\"width: 490px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2009\/09\/MTSAT_2009259_1530_GHOST_HURRICANEEYE.GIF\" target=\"_blank\"><img loading=\"lazy\" decoding=\"async\" class=\"   \" title=\"Night-time MTSAT-1R 3.75 \u00c2\u00b5m shortwave IR image (15:30 UTC)\" src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2009\/09\/MTSAT_2009259_1530_GHOST_HURRICANEEYE.GIF\" alt=\"MTSAT-1R shortwave IR image (15:30 UTC)\" width=\"480\" height=\"384\" \/><\/a><p class=\"wp-caption-text\">Night-time MTSAT-1R 3.75 \u00c2\u00b5m shortwave IR image (15:30 UTC)<\/p><\/div>\n<p>This false eye artifact was also evident during local daytime hours, but the &#8220;ghost&#8221; did not exhibit zero radiance &#8212; the feature could be seen better on the shortwave IR imagery once a contrast stretch\u00c2\u00a0 enhancement was applied <em><strong>(below)<\/strong><\/em>. The offsets of the false eye were the same as seen during local night-time hours.<\/p>\n<p style=\"text-align: center;\">\n<div style=\"width: 490px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2009\/09\/mtsat_swir_vis_anim.gif\" target=\"_blank\"><img loading=\"lazy\" decoding=\"async\" class=\"   \" title=\"Daytime MTSAT-1R shortwave IR (original and enhanced) + MTSAT-1R visible images\" src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2009\/09\/mtsat_swir_vis_anim.gif\" alt=\"MTSAT-1R shortwave IR (original and enhanced) and visible images\" width=\"480\" height=\"384\" \/><\/a><p class=\"wp-caption-text\">Daytime MTSAT-1R shortwave IR (original and enhanced) + MTSAT-1R visible images<\/p><\/div>\n<p>A similar <em>(but less obvious)<\/em> image artifact could be seen on a night-time shortwave IR image over China <em><strong>(below)<\/strong><\/em> &#8212; there was a bright white &#8220;ghost&#8221;\u00c2\u00a0 to the\u00c2\u00a0 right of the warm area that was between the two colder cloud features <em>(again, the ghost feature was offset to the east by 16 pixels with a vertical displacement of 1-2 pixels)<\/em>.<\/p>\n<p style=\"text-align: center;\">\n<div style=\"width: 490px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2009\/09\/MTSAT_2009259_1730_GHOST_CHINA.GIF\" target=\"_blank\"><img loading=\"lazy\" decoding=\"async\" class=\" \" title=\"Night-time MTSAT-1R 3.75 \u00c2\u00b5m shortwave IR image (over China)\" src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2009\/09\/MTSAT_2009259_1730_GHOST_CHINA.GIF\" alt=\"Night-time MTSAT-1R 3.75 \u00c2\u00b5m shortwave IR image (over China)\" width=\"480\" height=\"384\" \/><\/a><p class=\"wp-caption-text\">Night-time MTSAT-1R 3.75 \u00c2\u00b5m shortwave IR image (over China)<\/p><\/div>\n<p>The exact cause of these image artifacts is not known; however, since the MTSAT-1R satellite scans from left to right using a <a title=\"CCD (Wikipedia)\" href=\"http:\/\/http:\/\/en.wikipedia.org\/wiki\/Charge-coupled_device\" target=\"_blank\"><strong>Charge-Coupled Device (CCD)<\/strong><\/a> array,\u00c2\u00a0 the satellite sensor may be overcompensating for the CCD &#8220;quantum wells&#8221; losing more charge faster than expected, subtracting more of a bias than it should <em>(this could also be a side-effect of sensor aging)<\/em>. Instrument cross-talk could be another source of this type of image anomaly.<\/p>\n<p><em><strong>Kudos to Chris Schmidt at CIMSS for processing and analyzing these MTSAT-1R images, and supplying the explanations of possible causes of such an image artifact.<\/strong><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>A curious image artifact was noted on MTSAT-1R 3.75 \u00c2\u00b5m shortwave IR imagery, in the form of a very cold &#8220;false eye&#8221; appearing\u00c2\u00a0 just to the right of the actual eye of Typhoon Choi-Wan (17W) in the western North Pacific Ocean . The &#8220;ghost&#8221; of the eye exhibited a satellite radiance of zero (very cold, [&hellip;]<\/p>\n","protected":false},"author":18,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[20,38],"tags":[],"class_list":["post-3457","post","type-post","status-publish","format-standard","hentry","category-mtsat","category-what-the-heck-is-this"],"acf":[],"_links":{"self":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/3457","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=3457"}],"version-history":[{"count":7,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/3457\/revisions"}],"predecessor-version":[{"id":3464,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/3457\/revisions\/3464"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=3457"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=3457"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=3457"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}