{"id":4094,"date":"2009-12-07T23:59:18","date_gmt":"2009-12-07T23:59:18","guid":{"rendered":"http:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=4094"},"modified":"2010-05-20T20:10:42","modified_gmt":"2010-05-20T20:10:42","slug":"terrain-induced-cloud-features-off-the-coast-of-western-north-america","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/4094","title":{"rendered":"Terrain-induced cloud features off the coast of western North America"},"content":{"rendered":"
\"GOES-11<\/a>

GOES-11 and GOES-14 visible channel images<\/p><\/div>\n

A comparison of GOES-11 and GOES-14 (which was undergoing its NOAA Science Test<\/a><\/strong>) visible channel images (above; <\/strong>also available as a QuickTime animation<\/a>)<\/em><\/strong> showed a series of standing waves to the lee of Isla Guadalupe and also to the lee of Baja California on 07 December 2009<\/a><\/strong>. These terrain features were acting as an obstacle to strong westerly flow within the marine boundary layer, which initiated the formation of the lee waves.<\/p>\n

A signature of these lee waves was also evident on GOES-14 (and to a lesser extent, GOES-11)<\/em> water vapor channel images (below;<\/strong> also available as a QuickTime animation<\/a>)<\/em><\/strong>. The spatial resolution of the 6.5 \u00c2\u00b5m GOES-14 water vapor channel is 4 km, compared to the 8 km resolution of the 6.7 \u00c2\u00b5m water vapor channel on GOES-11 — this allowed the wave structure to be observed with greater clarity using GOES-14.<\/p>\n

\"GOES-11<\/a>

GOES-11 and GOES-14 water vapor images<\/p><\/div>\n

A MODIS 11.0 \u00c2\u00b5m IR image with an overlay of 1-hour MADIS atmospheric motion vectors (below)<\/em><\/strong> showed that lower tropospheric wind speeds were as high as 50 knots over the region.<\/p>\n

\"MODIS<\/a>

MODIS IR image + MADIS 1-hour wind vectors<\/p><\/div>\n

AVHRR Cloud Top Height (CTH) and Cloud Top Temperature (CTT) products (below)<\/em><\/strong> indicated the the crests of the waves immediately downwind of Isla Guadalupe exhibited CTH values as high as to 5 km and CTT values as cold as -30\u00c2\u00ba C — the surrounding marine stratoculumus clouds had CTH values near 2 km and CTT values around +2\u00c2\u00ba C.<\/p>\n

\"AVHRR<\/a>

AVHRR Cloud Top Height and Cloud Top Temperature products<\/p><\/div>\n

Farther to the north, GOES-11 and GOES-14 visible channel images (below; <\/strong>also available as a QuickTime animation<\/a>)<\/em><\/strong> revealed a long cloud plume that had formed downwind of Mount Olympus in far northwestern Washington. Strong northeasterly flow had developed over the region in response to the formation of a broad trough of low pressure<\/a><\/strong> over the western US. Note the improvement in GOES-14 Image Navigation and Registration (INR), with much less image-to-image wobble compared to GOES-11.<\/p>\n

\"GOES-11<\/a>

GOES-11 and GOES-14 visible channel images<\/p><\/div>\n

A MODIS fog\/stratus product image (below)<\/em><\/strong> showed that this cloud plume was also apparent during the pre-dawn hours, before any visible channel imagery would have been available.<\/p>\n

\"MODIS<\/a>

MODIS fog\/stratus product<\/p><\/div>\n

A MODIS 3-channel Red\/Green\/Blue (RGB) image (below)<\/em><\/strong> suggested that this cloud plume was comprised primarily of supercooled water droplets, which exhibit a brighter appearance on the RGB image — ice crystal clouds would have more of a pink-colored look on such an RGB image (like that seen with the deep snow cover over the interior mountains)<\/em><\/p>\n

\"MODIS<\/a>

MODIS false color Red\/Green\/Blue (RGB) image<\/p><\/div>\n

A MODIS visible channel image with an overlay of RUC80 850 hPa winds (below)<\/em><\/strong> confirmed the presence of northeasterly flow over the region. As the flow moved around the obstacle of Mount Olympus, lee-side convergence helped to aid in the formation of the cloud plume.<\/p>\n

\"MODIS<\/a>

MODIS visible image + RUC80 850 hPa winds<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"

A comparison of GOES-11 and GOES-14 (which was undergoing its NOAA Science Test) visible channel images (above; also available as a QuickTime animation) showed a series of standing waves to the lee of Isla Guadalupe and also to the lee of Baja California on 07 December 2009. These terrain features were acting as an obstacle […]<\/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":[22,13,18,40,12,26,45,25],"tags":[],"class_list":["post-4094","post","type-post","status-publish","format-standard","hentry","category-avhrr","category-fog-detection","category-goes-11","category-goes-14","category-modis","category-poes","category-redgreenblue-rgb-images","category-satellite-winds"],"acf":[],"_links":{"self":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/4094","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=4094"}],"version-history":[{"count":9,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/4094\/revisions"}],"predecessor-version":[{"id":5727,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/4094\/revisions\/5727"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=4094"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=4094"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=4094"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}