{"id":51689,"date":"2023-04-13T13:10:00","date_gmt":"2023-04-13T13:10:00","guid":{"rendered":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=51689"},"modified":"2023-04-18T19:58:23","modified_gmt":"2023-04-18T19:58:23","slug":"banded-wind-structures-over-lake-huron","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/51689","title":{"rendered":"Banded wind structures over Lake Huron"},"content":{"rendered":"\n
\"\"<\/a>
RCM-2 SAR Winds on 1144 UTC on 13 April 2023 (click to enlarge)<\/figcaption><\/figure>\n\n\n\n

The SAR wind analysis above shows curious banded wind features over central Lake Huron. The bands have a vertical separation of around 10 km and exist just south of essentially calm winds (magenta in the enhancement used). Peak winds within the bands 8-10 m\/s, and the (weaker) winds in between the peaks are 4-6 m\/s. Because this blogger can’t quite figure out why they’re there, the ‘What the Heck is this?’ category is being used. The region of light winds is between a cold front to the north, and high pressure to the south (1500 UTC surface analysis<\/a>). The slider below compares the wind field to the 3.9 \u00b5m<\/a> brightness temperature field<\/a> (Note that only values between 0 and 6o<\/sup> C are shown). There is an obvious relationship between brightness temperatures between the very light winds between northern lower Michigan and Manitoulin Island — the lake surface has brightness temperatures between 2.2o<\/sup> and 2.8o<\/sup> C where winds are lighter vs. 3o<\/sup> – 3.9o<\/sup> C where stronger winds exist to the south; however, the banded wind features do not appear to have an appreciable effect on the underlying lake surface temperatures.<\/p>\n\n\n\n

The 1200 UTC sounding from Detroit<\/a>, from the Wyoming Sounding site<\/a>, shows stable air below 800 mb. The airmass will be chilled from beneath when it moves over the Lake, too, so a strong surface inversion likely exists as well.<\/p>\n\n\n\n\t\n\t\t\n\t\t\t<\/polyline>\n\t\t\t<\/polyline>\n\t\t\t<\/polyline>\n\t\t\t<\/polyline>\n\t\t\t<\/svg>\n\t\t<\/span>\n\t<\/span>\n<\/div>\n\n\n\n\n\n

The toggle below compares derived winds<\/a> and Normalized Radar Cross Section (NRCS)<\/a> fields at 1144 UTC from RCM-2 observations.<\/p>\n\n\n\n

\"\"<\/a>
RCM2 Derived SAR Winds and Normalized Radar Cross Section values, 1144 UTC on 13 April 2023 (Click to enlarge)<\/figcaption><\/figure>\n\n\n\n
\n\n\n\n

Added: 17 April 2023: This website<\/a> shows SAR data over Lake Huron only (other individual Great Lakes views are available here<\/a>). Included at the Lake Huron website is a netcdf file that combines both scenes on this day over Lake Huron, shown below in a slider with the GOES-16 Low-Level water vapor imagery (that is, Band 10 at 7.34 \u00b5m). There are features in the ABI imagery that overlap the wind features. (Click here<\/a> to see a toggle). Note that the color enhancement bounds have been altered slightly from the default (-109 to 55 o<\/sup>C) to -107 to 58 o<\/sup>C to make the bands more obvious.<\/p>\n\n\n\n\t\n\t\t\n\t\t\t<\/polyline>\n\t\t\t<\/polyline>\n\t\t\t<\/polyline>\n\t\t\t<\/polyline>\n\t\t\t<\/svg>\n\t\t<\/span>\n\t<\/span>\n<\/div>\n\n\n\n\n\n

\n\n\n\n

The animation of GOES-16 Band 10 imagery from 1101 – 1201 UTC (i.e. bracketing the SAR observations), below, shows that the bands persist, at least for this hour, and perhaps the wind features extend inland over lower Michigan; at least, the features in the Band 10 imagery show up there!<\/p>\n\n\n\n

\"\"<\/a>
GOES-16 Band 10 (Low-Level Water Vapor) infrared (7.34 \u00b5m) imagery, 1101 – 1201 UTC on 13 April 2023. (Click to enlarge)<\/figcaption><\/figure>\n\n\n\n
\n\n\n\n

The computed weighting function for the Detroit sounding at 1200 UTC on 13 April 2023, below, (from the CIMSS Weighting Function site<\/a>) shows results for the three ABI infrared Water Vapor channels (Bands 8, 9 and 10 at 6.19, 6.95 and 7.34 \u00b5m, respectively). Much of the energy sensed by the ABI at 7.34 \u00b5m originates from a layer between 600 and 700 mb. <\/p>\n\n\n\n

\"\"<\/a>
Weighting Functions for GOES-16’s ABI infrared Water Vapor channels (Bands 8, 9 and 10) (Click to enlarge)<\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"

The SAR wind analysis above shows curious banded wind features over central Lake Huron. The bands have a vertical separation of around 10 km and exist just south of essentially calm winds (magenta in the enhancement used). Peak winds within the bands 8-10 m\/s, and the (weaker) winds in between the peaks are 4-6 m\/s. […]<\/p>\n","protected":false},"author":19,"featured_media":51699,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[74,104,25,38],"tags":[],"class_list":["post-51689","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-goes-16","category-sar","category-satellite-winds","category-what-the-heck-is-this"],"acf":[],"_links":{"self":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/51689","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\/19"}],"replies":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/comments?post=51689"}],"version-history":[{"count":15,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/51689\/revisions"}],"predecessor-version":[{"id":51767,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/51689\/revisions\/51767"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media\/51699"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=51689"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=51689"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=51689"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}