{"id":20756,"date":"2016-02-18T23:59:24","date_gmt":"2016-02-18T23:59:24","guid":{"rendered":"http:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=20756"},"modified":"2016-03-09T16:26:13","modified_gmt":"2016-03-09T16:26:13","slug":"why-1-minute-data-matters-monitoring-fires","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/20756","title":{"rendered":"Why 1-minute satellite data matters: Monitoring Fires"},"content":{"rendered":"

\"GOES-14<\/a>

GOES-14 0.63 \u00b5m Visible (top) and 3.9 \u00b5m Shortwave Infrared (bottom) images [click to play MP4 animation]<\/p><\/div>Extensive wildfires (well-forecast by the Storm Prediction Center<\/a>) occurred over the southern Plains on Thursday 18 February 2016<\/a>, while GOES-14 was operating in SRSO-R mode<\/a>. A comparison of 1-minute GOES-14 Visible (0.63 \u00b5m) and Shortwave Infrared (3.9 \u00b5m) images (above; also available as a large 112 Mbyte animated GIF<\/a>) showed the broad areal coverage of smoke plumes and fire hot spots (dark black to yellow to red pixels) during the day over eastern Oklahoma.<\/p>\n

\"GOES-14<\/a>

GOES-14 0.63 \u00b5m Visible (left) and 3.9 \u00b5m Shortwave Infrared (right) images [click to play MP4 animation]<\/p><\/div>Of particular interest was a rapidly-intensifying and fast-moving grass fire over northwestern Oklahoma, in Harper County just west-northwest of the town of Buffalo, which burned 17,280 acres (media report<\/a>). Note the warm air temperatures as seen in the surface plots — the high of 90\u00ba F at Gage OK (KGAG, south of the fire) tied for the warmest February temperature on record at that site. A closer view of the Buffalo fire is shown above — county outlines are shown as dashed white lines, while US and State highways are plotted in violet (also available as a large 63 Mbyte animated GIF<\/a>). The shortwave infrared images revealed the initial appearance of a color-enhanced fire hot spot (exhibiting an IR brightness temperature of 327.5 K) at 2045 UTC; three minutes later (at 2048 UTC), the IR brightness temperature had already increased to 341.2 K (red enhancement) which is the saturation temperature of the GOES-14 shortwave IR detectors. The hot spots could also be seen racing northeastward toward the Oklahoma\/Kansas border, with the fire eventually crossing US Highway 183 (which runs south-to-north through Buffalo and across the Kansas border). The early detection and subsequent accurate tracking of such rapid fire intensification and propagation could only have been possible using 1-minute imagery.<\/p>\n

The two plots below show GOES-14 pixel values of 3.9\u00a0\u00b5m IR brightness temperature at the initial Buffalo fire site (top plot, at 36:51\u00ba N, 99:48\u00ba W) and at a site just to the northeast (bottom plot, at 36:54\u00ba N, 99:43\u00ba W) through which the moving fire propagated. The blue line shows every value, nominally at 1-minute intervals. The red dots show points sampled every five minutes. Very small temporal scale changes in the fire cannot be captured with a 5-minute sampling interval.<\/p>\n

\"GOES-14<\/a>

GOES-14 Shortwave Infrared (3.9 \u00b5m) Brightness Temperatures at 36:51:36\u00ba N, 99:48:27\u00ba W, 2040-2230 UTC on 18 February 2016 [click to enlarge]<\/p><\/div>

\"GOES-14<\/a>

GOES-14 Shortwave Infrared (3.9 \u00b5m) Brightness Temperatures at 36:54:44\u00ba N, 99:43:22\u00ba W, 2115-2200 UTC on 18 February 2016 [click to enlarge]<\/p><\/div> <\/p>\n

\"GOES-15<\/a>

GOES-15 (left), GOES-14 (center), and GOES-13 (right) 3.9 \u00b5m Shortwave Infrared images covering the initial period 2030-2100 UTC [click to play animation]<\/p><\/div>For the Buffalo fire, a three-satellite comparison of Shortwave Infrared (3.9 \u00b5m) images from GOES-15 (operational GOES-West), GOES-14, and GOES-13 (operational GOES-East) is shown for the initial 30-minute time period 2030-2100 UTC (above). The images are displayed in the native projection of each satellite. In terms of the first unambiguous fire hot spot detection (via a hot color-enhanced image pixel) during that initial period, it would appear from the image time stamps that both GOES-14 and GOES-13 detected the fire at 2045 UTC — however, because GOES-14 was scanning a much smaller sector<\/a>, it did indeed scan the fire at 20:45 UTC (while GOES-13 scanned the fire at 2049 UTC, 4 minutes after its larger scan sector began in southern Canada). Also note that there were no GOES-15 images during that 30-minue period between 2030 and 2100 UTC, due to the satellite having to perform various “housekeeping” activities — so if a NWS forecast office AWIPS were localized to use GOES-15, initial fire detection would not have been posible until reception of the 2100 UTC image (which actually scanned the fire at 2104 UTC).<\/p>\n

A faster animation covering a longer 2.5-hour period from 2030-2300 UTC is shown below. Again, a true sense of the fast northeastward speed of fire propagation could only be gained using 1-minute imagery.<\/p>\n

\"GOES-15<\/a>

GOES-15 (left), GOES-14 (center), and GOES-13 (right) 3.9 \u00b5m Shortwave Infrared images covering the 2.5 hour period 2030-2300 UTC [click to play animation]<\/p><\/div>\n

\"GOES-14<\/a>

GOES-14 Shortwave Infrared (3.9 \u00b5m) 9mages [click to play animation]<\/p><\/div>The animation above shows another view of 1-minute GOES-14 Shortwave Infrared (3.9 \u00b5m) imagery, centered over northeastern Oklahoma — in these images, the hottest fire pixels are darkest black. Time series of infrared brightness temperature values at two individual fire pixels (shown here<\/a>) are plotted below. The Blue lines show the 1-minute data; Red dots show how 5-minute monitoring would have adequately captured the events. Pixel Brightness Temperature changes that occur on the order of 1 or 2 minutes are common, and peak values can be missed with 5-minute granularity.<\/p>\n

\"GOES-14<\/a>

GOES-14 Shortwave Infrared (3.9 \u00b5m) Brightness Temperatures from 2138-2301 UTC on 18 February 2016, at 35:31:17\u00ba N, 96:05:55\u00ba W [click to enlarge]<\/p><\/div>

\"GOES-14<\/a>

GOES-14 Shortwave Infrared (3.9 \u00b5m) Brightness Temperatures from 2138-2301 UTC on 18 February 2016, at 35:23:51\u00ba N, 95:20:52\u00ba W [click to enlarge]<\/p><\/div>In the GOES-R<\/a> era, Fire Products will be produced every 5 minutes. Individual NWS Forecast Offices will be able to request Rapid-Scan Imagery (1-minute intervals) over a 1000 km x 1000 km mesoscale sector.<\/p>\n

===== 19 February Update =====<\/strong><\/p>\n

Seen below are RealEarth<\/a> comparisons of Aqua MODIS and Suomi NPP VIIRS true-color Red\/Green\/Blue (RGB) images from the early afternoon of 18 February (before the Buffalo OK fire) and 19 February (after the Buffalo OK fire), which revealed the long southwest-to-northeast oriented burn scar. As seen on the GOES-14 animation above, the fire crossed US Highway 183 just to the north of Buffalo (that portion of the highway was closed for several hours).<\/p>\n

\"Aqua<\/a>

Aqua MODIS true-color images on 18 February and 19 February [click to enlarge]<\/p><\/div>

\"Suomi<\/a>

Suomi NPP VIIRS true-color images on 18 February and 19 February [click to enlarge]<\/p><\/div>In addition, a comparison of Suomi NPP VIIRS true-color and false-color images (below) helps to discriminate between the darker burn scar and the cloud shadows seen on the true-color image — the Buffalo fire burn scar appears as varying shades of brown in both the true-color and the false-color images.<\/p>\n

\"Suomi<\/a>

Suomi NPP VIIRS true-color and false-color images [click to enlarge]<\/p><\/div>\n

===== 27 February Update =====<\/strong><\/p>\n

\"Landsat-8<\/a>

Landsat-8 false-color RGB images on 18 February (a few hours prior to the start of the fire) and 27 February (several says after the fire) [click to enlarge]<\/p><\/div>A comparison of 30-meter resolution Landsat-8 false-color (created using OLI<\/a> bands 6\/5\/4) RGB images from 18 February (about 3.5 hours prior to the start of the Buffalo OK fire) and 27 February (several days after the fire) provided a very detailed view of the burn scar. Note that a few green fields remained within the burn scar, and also appeared to prevent the spread of the fire along portions of its perimeter — this is a result of the vast difference between the very low moisture content of the dry<\/a> grassland (which burned quickly and easily) and the high moisture content of the well-irrigated fields of winter wheat, alfalfa, and canola crops.<\/p>\n","protected":false},"excerpt":{"rendered":"

Extensive wildfires (well-forecast by the Storm Prediction Center) occurred over the southern Plains on Thursday 18 February 2016, while GOES-14 was operating in SRSO-R mode. A comparison of 1-minute GOES-14 Visible (0.63 \u00b5m) and Shortwave Infrared (3.9 \u00b5m) images (above; also available as a large 112 Mbyte animated GIF) showed the broad areal coverage of […]<\/p>\n","protected":false},"author":19,"featured_media":20772,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[6,11,40,43,34,55,12,53,45,49,48],"tags":[],"class_list":["post-20756","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-fire-detection","category-goes-13","category-goes-14","category-goes-15","category-goes-r","category-landsat","category-modis","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\/20756","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=20756"}],"version-history":[{"count":44,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/20756\/revisions"}],"predecessor-version":[{"id":20898,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/20756\/revisions\/20898"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media\/20772"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=20756"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=20756"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=20756"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}