{"id":37353,"date":"2020-06-27T23:59:09","date_gmt":"2020-06-27T23:59:09","guid":{"rendered":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=37353"},"modified":"2020-06-29T03:29:15","modified_gmt":"2020-06-29T03:29:15","slug":"exploring-the-effects-of-parallax-over-alaska","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/37353","title":{"rendered":"Exploring the effects of GOES-17 parallax over Alaska"},"content":{"rendered":"

\"GOES-17<\/a>

Topography, GOES-17 \u201cRed\u201d Visible (0.64 \u00b5m)<\/em> and “Clean” Infrared Window (10.35 \u00b5m)<\/em> images [click to play animation | MP4<\/strong><\/a>]<\/p><\/div>GOES-17 (GOES-West)<\/em> \u201cRed\u201d Visible (0.64 \u00b5m<\/strong><\/a>) and “Clean” Infrared Window (10.35 \u00b5m<\/strong><\/a>) images (above)<\/strong><\/em> displayed the formation of an orographic rotor cloud downwind (north-northeast) of the Kigluaik and Bendeleben Mountains in the Seward Peninsula<\/strong><\/a> of Alaska on 27 June 2020. Even though the highest terrain in those mountain ranges was only 3700-4700 feet (1.1-1.4 km), the coldest cloud-top infrared brightness temperatures within the rotor cloud feature were around -50 to -51\u00baC.<\/p>\n

A plot of rawinsonde data<\/strong><\/a> from Nome (below)<\/strong><\/em> showed the strong southwesterly winds that existed within most the troposphere on that day. The tropopause temperatures were around -51\u00baC at altitudes of 9.4-9.6 km — indicating that these high-altitude rotor clouds were forced by vertically-propagating waves initiated by interaction of the anomalously-strong<\/strong><\/a> southerly\/southwesterly lower-tropospheric flow with the west-to-east oriented mountain ranges.<\/p>\n

\"Plot<\/a>

Plot of rawinsonde data from Nome, Alaska [click to enlarge]<\/p><\/div>Comparisons of topography and Visible\/Infrared images from Suomi NPP and GOES-17 around 1320 UTC and 2140 UTC are shown below. Since there is generally very little parallax<\/strong><\/a> offset associated with imagery from polar-orbiting satellites (such as Suomi NPP), the rotor cloud appeared closer to the topography that helped to force development of that cloud feature.<\/p>\n

\"Topography,<\/a>

Topography, Suomi NPP VIIRS Visible (0.64 \u00b5m)<\/em> and GOES-17 “Red” Visible (0.64 \u00b5m)<\/em> images around 1320 UTC [click to enlarge]<\/p><\/div>

\"Topography,<\/a>

Topography, Suomi NPP VIIRS Infrared Window (11.45 \u00b5m)<\/em> and GOES-17 “Clean” Infrared Window (10.35 \u00b5m)<\/em> images around 1320 UTC [click to enlarge]<\/p><\/div>

\"Topography,<\/a>

Topography, Suomi NPP VIIRS Visible (0.64 \u00b5m)<\/em> and GOES-17 “Red” Visible (0.64 \u00b5m)<\/em> images around 2140 UTC [click to enlarge]<\/p><\/div>

\"Topography,<\/a>

Topography, Suomi NPP VIIRS Infrared Window (11.45 \u00b5m)<\/em> and GOES-17 “Clean” Infrared Window (10.35 \u00b5m)<\/em> images around 2140 UTC [click to enlarge]<\/p><\/div>Plots of GOES-17 parallax correction vectors and displacements (in km) for a 30,00-feet (9.1 km) cloud feature at select points over the Alaska region (from this site<\/strong><\/a>) are shown below. For such a cloud feature over the Seward Peninsula, the parallax offset would be about 40 km (25 miles) — which closely corresponded to the offset seen between the GOES-17 and Suomi NPP images shown above.<\/p>\n

\"Plots<\/a>

Plots of GOES-17 parallax correction vectors and displacements (in km) for a 30,000-foot (9.1 km) cloud feature at select points over the Alaska region [click to enlarge]<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"

GOES-17 (GOES-West) \u201cRed\u201d Visible (0.64 \u00b5m) and “Clean” Infrared Window (10.35 \u00b5m) images (above) displayed the formation of an orographic rotor cloud downwind (north-northeast) of the Kigluaik and Bendeleben Mountains in the Seward Peninsula of Alaska on 27 June 2020. Even though the highest terrain in those mountain ranges was only 3700-4700 feet (1.1-1.4 km), […]<\/p>\n","protected":false},"author":18,"featured_media":37355,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[80,49,48],"tags":[],"class_list":["post-37353","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-goes-17","category-suomi_npp","category-viirs"],"acf":[],"_links":{"self":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/37353","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=37353"}],"version-history":[{"count":7,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/37353\/revisions"}],"predecessor-version":[{"id":37361,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/37353\/revisions\/37361"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media\/37355"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=37353"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=37353"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=37353"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}