{"id":17390,"date":"2014-12-21T23:45:39","date_gmt":"2014-12-21T23:45:39","guid":{"rendered":"http:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=17390"},"modified":"2014-12-22T20:05:30","modified_gmt":"2014-12-22T20:05:30","slug":"mountain-wave-clouds-over-southern-california","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/17390","title":{"rendered":"Mountain wave clouds over southern California"},"content":{"rendered":"
\"GOES-15<\/a>

GOES-15 6.5 \u00b5m water vapor channel images click to play animation)<\/p><\/div>\n

AWIPS images of 4-km resolution resolution GOES-15 (GOES-West) 6.5 \u00b5m water vapor channel data (above; click image to play animation)<\/strong><\/em> showed the development of a patch of mountain wave or “lee wave” clouds immediately downwind of the higher elevations of the western Transverse Ranges<\/strong><\/a> in southern California on 21 December 2014<\/strong><\/a>.\u00a0 These clouds developed in response to strong northerly winds interacting with the west-to-east oriented topography (12 UTC NAM 700 hPa wind and height<\/strong><\/a>). As seen on the plotted surface reports, at Sandberg (station identifier KSDB)<\/em> the highest wind gust was 52 knots or 59 mph\u00a0 at 17:42 UTC — and later in the day there also a peak wind gust of 87 mph at Whitaker Peak and 86 mph at Montcito Hills<\/strong><\/a>. In addition, there were isolated pilot reports of moderate turbulence in the vicinity of the mountain wave cloud at 20:21 UTC<\/strong><\/a> and 23:06 UTC<\/strong><\/a>;\u00a0 farther to the east there was a pilot report of moderate to severe turbulence at 01:27 UTC<\/strong><\/a>.<\/p>\n

A comparison of 1-km resolution MODIS 6.7 \u00b5m and 4-km resolution GOES-15 6.5 \u00b5m water vapor channel images around 21:00 UTC (below)<\/strong><\/em> demonstrated the advantage of higher spatial resolution (and the minimal parallax<\/strong><\/a> offset)<\/em> of the polar-orbiter MODIS imagery for more accurate location of the mountain wave cloud.<\/p>\n

\"MODIS<\/a>

MODIS 6.7 \u00b5m and GOES-15 6.5 \u00b5m water vapor channel images<\/p><\/div>\n

At 20:42 UTC (below),<\/strong><\/em> the coldest 1-km resolution POES AVHRR Cloud Top Temperature value associated with the mountain wave cloud feature was -69\u00ba C (darker red color enhancement),<\/em> with the highest Cloud Top Height value being 14 km or 45,900 ft (cyan color enhancement)<\/em>., which is actually colder and higher than the tropopause on\u00a0 the 12 UTC rawinsonde report at Vandenberg AFB<\/strong><\/a>. The highest elevation in the western portion of the Transverse Ranges where the mountain wave cloud formed is Mount Pinos at 8847 feet or 2697 meters, so it appears that a vertically-propagating wave developed which helped the cloud reach such a high altitude.<\/p>\n

\"POES<\/a>

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

At 21;20 UTC, a comparison of 375-meter resolution (projected onto a 1-km resolution AWIPS grid)<\/em> Suomi NPP VIIRS 0.64 \u00b5m visible channel, 3.74 \u00b5m shortwave IR channel, and 11.45 \u00b5m IR channel images (below)<\/strong><\/em> showed that while the coldest cloud-top 11.45 \u00b5m IR brightness temperatures were around -60\u00ba C, the 3.74 \u00b5m shortwave IR temperatures were in the +5 to +10\u00ba C range — this indicates that the mountain wave cloud was composed of very small<\/em> ice particles, which were efficient reflectors of solar radiation contributing to much the warmer shortwave IR brightness temperatures.<\/p>\n

\"Suomi<\/a>

Suomi NPP VIIRS 0.64 \u00b5m visible, 3.74 \u00b5m shortwave IR, and 11 45 \u00b5m IR channel images<\/p><\/div>\n

A 375-meter resolution Suomi NPP VIIRS true-color Red\/Green\/Blue (RGB) image from the SSEC RealEarth<\/strong><\/a> web map server is shown below.<\/p>\n

\"Suomi<\/a>

Suomi NPP VIIRS true-color image<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"

AWIPS images of 4-km resolution resolution GOES-15 (GOES-West) 6.5 \u00b5m water vapor channel data (above; click image to play animation) showed the development of a patch of mountain wave or “lee wave” clouds immediately downwind of the higher elevations of the western Transverse Ranges in southern California on 21 December 2014.\u00a0 These clouds developed in […]<\/p>\n","protected":false},"author":18,"featured_media":17392,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[22,21,43,12,26,53,45,49,48],"tags":[],"class_list":["post-17390","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-avhrr","category-aviation","category-goes-15","category-modis","category-poes","category-real-earth","category-redgreenblue-rgb-images","category-suomi_npp","category-viirs"],"acf":[],"_links":{"self":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/17390","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=17390"}],"version-history":[{"count":19,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/17390\/revisions"}],"predecessor-version":[{"id":17413,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/17390\/revisions\/17413"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media\/17392"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=17390"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=17390"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=17390"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}