![\"MODIS](\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2018\/12\/181203_modis_viirs_fogBTD_Upper_Midwest_plumes_anim.gif\")
<\/a>MODIS and VIIRS “Fog\/stratus” BTD images [click to enlarge]<\/p><\/div>A sequence of nighttime MODIS and VIIRS “Fog\/stratus” infrared Brightness Temperature Difference (BTD) images (above)<\/strong><\/em> revealed long plumes (darker shades of red)<\/em> streaming southwestward for over 200 miles from their industrial point sources in the Mesabi Range<\/strong><\/a> of northeastern Minnesota on 03 December 2018<\/strong><\/a>.<\/p>\n During the subsequent daytime hours, a comparison of GOES-16 (GOES-East)<\/em> “Red” Visible (0.64 \u00b5m<\/strong><\/a>), Near-Infrared “Snow\/Ice” (1.61 \u00b5m<\/strong><\/a>), Near-Infrared “Cloud Particle Size” (2.24 \u00b5m<\/strong><\/a>) and Shortwave Infrared (3.9 \u00b5m<\/strong><\/a>) images (below)<\/strong><\/em> showed signatures of these Mesabi Range plumes along with others emanating from industrial or power plant sources. A few ship tracks were also apparent across Lake Superior.<\/p>\n Particles emitted from the exhaust stacks at power plants and industrial sites (as well as ships) can act as efficient cloud condensation nuclei, which causes the formation of large numbers of supercooled water droplets having a smaller<\/em> diameter than those found within the adjacent unperturbed supercooled clouds — and these smaller supercooled cloud droplets are better reflectors of incoming solar radiation, thereby appearing brighter in the Near-Infrared and warmer (darker gray)<\/em> in the Shortwave Infrared images.<\/p>\n GOES-16 “Red” Visible (0.64 \u00b5m),<\/em> Near-Infrared “Snow\/Ice” (1.61 \u00b5m),<\/em> Near-Infrared “Cloud Particle Size” (2.24 \u00b5m)<\/em> and Shortwave Infrared (3.9 \u00b5m)<\/em> images [click to play animation | MP4<\/strong><\/a>]<\/p><\/div>On the following night, another sequence of MODIS and VIIRS “Fog\/stratus” infrared Brightness Temperature Difference (BTD) images (below)<\/strong><\/em> highlighted a number of industrial and power plant plumes across Minnesota, northern Wisconsin and the Upper Peninsula of Michigan. The curved shape of many of these plumes resulted from boundary layer winds shifting from northerly to westerly as the night progressed.<\/p>\n MODIS and VIIRS “Fog\/stratus” BTD images [click to enlarge]<\/p><\/div>During the following daytime hours on 04 December<\/a><\/strong>, a comparison of VIIRS Visible (0.64 \u00b5m), Near-Infrared “Snow\/Ice” (1.61 \u00b5m), Shortwave Infrared (3.74 \u00b5m) and Infrared Window (11.45 \u00b5m) images (below)<\/strong><\/em> showed 2 plume types across eastern Nebraska. There were several of the brighter\/warmer plumes similar to those noted on the previous day across Minnesota\/Wisconsin\/Michigan — but one large plume originating from industrial sites just east of Norfolk (KOFK) had the effect of eroding the supercooled cloud deck via glaciation (initiated by the emission of particles that acted as efficient ice nuclei<\/em>) and subsequent snowfall. This is similar to the process that creates aircraft “distrails” or “fall streak clouds” as documented here<\/a><\/strong>, here<\/a><\/strong> and here<\/a><\/strong>.<\/p>\n VIIRS Visible (0.64 \u00b5m),<\/em> Near-Infrared “Snow\/Ice” (1.61 \u00b5m),<\/em> Shortwave Infrared (3.74 \u00b5m)<\/em> and Infrared Window (11.45 \u00b5m)<\/em> images [click to enlarge]<\/p><\/div> It’s been confirmed that this snow band is originating from 2 plants in Norfolk. The steam produced there is essentially acting to add moisture and warmth to the clouds creating the snow. Had reports of large flake and up to 1in. If you live in that area how much have you seen? pic.twitter.com\/mSiVcj6uH2<\/a><\/p>\n \u2014 NWS Omaha (@NWSOmaha) December 3, 2018<\/a><\/p><\/blockquote>\n<\/a><\/a><\/a>
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