{"id":41794,"date":"2021-08-05T23:59:00","date_gmt":"2021-08-05T23:59:00","guid":{"rendered":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=41794"},"modified":"2021-08-10T13:06:09","modified_gmt":"2021-08-10T13:06:09","slug":"comparing-sar-data-over-lake-superior-to-radar","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/41794","title":{"rendered":"Comparing SAR data over Lake Superior to radar"},"content":{"rendered":"\n<figure class=\"wp-block-image size-large is-resized\"><a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2021\/08\/RCM2_SHUB_2021_08_05_23_40_58_0681522058_088.75W_47.61N_VV_C5_GFS05CDF_wind.png\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2021\/08\/RCM2_SHUB_2021_08_05_23_40_58_0681522058_088.75W_47.61N_VV_C5_GFS05CDF_wind-1000x1024.png\" alt=\"\" class=\"wp-image-41795\" width=\"817\" height=\"836\" srcset=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2021\/08\/RCM2_SHUB_2021_08_05_23_40_58_0681522058_088.75W_47.61N_VV_C5_GFS05CDF_wind-1000x1024.png 1000w, https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2021\/08\/RCM2_SHUB_2021_08_05_23_40_58_0681522058_088.75W_47.61N_VV_C5_GFS05CDF_wind-293x300.png 293w, https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2021\/08\/RCM2_SHUB_2021_08_05_23_40_58_0681522058_088.75W_47.61N_VV_C5_GFS05CDF_wind-768x787.png 768w, https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2021\/08\/RCM2_SHUB_2021_08_05_23_40_58_0681522058_088.75W_47.61N_VV_C5_GFS05CDF_wind-1500x1536.png 1500w, https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2021\/08\/RCM2_SHUB_2021_08_05_23_40_58_0681522058_088.75W_47.61N_VV_C5_GFS05CDF_wind.png 1909w\" sizes=\"auto, (max-width: 817px) 100vw, 817px\" \/><\/a><figcaption>SAR winds from RCM-2, 2340 UTC on 5 August 2021 (Click to enlarge)<\/figcaption><\/figure>\n\n\n\n<p>Synthetic Aperture Radar (SAR) winds are derived from a microwave signal pinged from a satellite; backscatter is converted into winds (given a background field that is typically from a numerical model).  The wind structure here is suggestive of a bowing feature to a convective downdraft.  How does it compare to radar or satellite imagery?  GOES-16 Satellite imagery for the hour bracketing the imagery above is shown below.  Convection (weak) is apparent moving east from the tip of Keewenaw peninsula.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2021\/08\/GOES-16_ABI_RadC_C02_20210805_2301_to_2356_SARSuperiorAnnot2anim.gif\"><img loading=\"lazy\" decoding=\"async\" width=\"960\" height=\"720\" src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2021\/08\/GOES-16_ABI_RadC_C02_20210805_2301_to_2356_SARSuperiorAnnot2anim.gif\" alt=\"\" class=\"wp-image-41800\" \/><\/a><figcaption>GOES-16 &#8220;Red&#8221; Visible (0.64mm) imagery, 2301-2356 UTC on 5 August 2021 (click to enlarge)<\/figcaption><\/figure>\n\n\n\n<p>What did radar imagery look like at this time? The imagery below, courtesy Nick Langlieb, the SOO at WFO Marquette, shows radar echoes (base reflectivity) at a different level than the Lake-surface values sampled by SAR, so a direct comparison is a challenge (click <a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2021\/08\/KMQT_CC.png\">here<\/a> to see Correlation Coefficient at the same time).  It&#8217;s peculiar that no radar signal is apparent to match the strong SAR winds just offshore from the tip of the Keewenaw peninsula (between 88\u00ba and 87.5\u00ba W) &#8212; although there is a feature oriented north-south a small distance to the west of the peninsular tip;  there seems to be a better (but not exact) match with the SAR winds near 87\u00ba W.  <\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2021\/08\/KMQT_Z.png\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"557\" src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2021\/08\/KMQT_Z-1024x557.png\" alt=\"\" class=\"wp-image-41803\" srcset=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2021\/08\/KMQT_Z-1024x557.png 1024w, https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2021\/08\/KMQT_Z-300x163.png 300w, https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2021\/08\/KMQT_Z-768x418.png 768w, https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2021\/08\/KMQT_Z-1536x835.png 1536w, https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2021\/08\/KMQT_Z.png 1920w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/a><figcaption>1.3\u00ba &#8211; Base Reflectivity, 2340 UTC on 5 August 2021 (click to enlarge)<\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Synthetic Aperture Radar (SAR) winds are derived from a microwave signal pinged from a satellite; backscatter is converted into winds (given a background field that is typically from a numerical model). The wind structure here is suggestive of a bowing feature to a convective downdraft. How does it compare to radar or satellite imagery? GOES-16 [&hellip;]<\/p>\n","protected":false},"author":19,"featured_media":41795,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[74,104,25],"tags":[],"class_list":["post-41794","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-goes-16","category-sar","category-satellite-winds"],"acf":[],"_links":{"self":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/41794","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=41794"}],"version-history":[{"count":8,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/41794\/revisions"}],"predecessor-version":[{"id":41810,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/41794\/revisions\/41810"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media\/41795"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=41794"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=41794"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=41794"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}