Carr Fire pyrocumulonimbus in California

July 27th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and Shortwave Infrared (3.9 µm, right) images [click to play MP4 animation]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above) showed the large thermal anomaly or “hot spot” (cluster of red pixels) associated with the Carr Fire in northern California as it produced a pyrocumulonimbus (pyroCb) cloud during the afternoon hours on 27 July 2018. A 30-meter resolution Landsat-8 False Color image from the previous day showed the large size of the burn scar; extreme fire behavior on 27 July caused the Carr Fire to quickly increase in size and move closer to Redding CA, and also produce the pyroCb.

Another view using GOES-16 “Red” Visible, Shortwave Infrared, “Clean” Infrared Window (10.3 µm) and the Cloud Top Temperature product (below) showed the pyroCb cloud as it drifted rapidly northeast over Nevada and Oregon, along with a second (albeit smaller) pyroCb cloud which developed around 0130 UTC. One standard parameter used for defining a pyroCb cloud is a minimum cloud-top longwave infrared brightness temperature of -40ºC (ensuring complete glaciation) — and in this case with 1-minute imagery, the multi-spectral Cloud Top Temperature (CTT) product (FAQ) indicated that the pyroCb cloud reached the -40ºC threshold 19 minutes earlier than the 10.3 µm infrared imagery. From that point forward, the CTT product was consistently at least 5-10ºC colder than the 10.3 µm brightness temperature; the CTT product eventually displayed a minimum value of -53.9ºC over northeastern California. Even as the 10.3 µm brightness temperature began to rapidly warm after about 0100 UTC, the CTT product continued to display values in the -45 to -50ºC range (shades of green) which allowed for unambiguous tracking of the pyroCb.

GOES-16 "Red" Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), "Clean" Infrared Window (10.3 µm, bottom left) and Cloud Top Temperature product (bottom right) [click to play MP4 animation]

GOES-16 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), “Clean” Infrared Window (10.3 µm, bottom left) and Cloud Top Temperature product (bottom right) [click to play MP4 animation]

In the case of the second (smaller) pyroCb cloud that formed from the Carr Fire after 0130 UTC, the 10.3 µm brightness temperature failed to reach the -40ºC threshold, while the CTT product again displayed values in the -45 to -50ºC range. The coldest CTT value of -53.9ºC (seen with the initial pyroCb) roughly corresponded to an altitude of 12.5 km or 41,000 feet according to 00 UTC rawinsonde data from Reno, Nevada (below). Strong upper-tropospheric winds of 80-90 knots rapidly transported the pyroCb anvil northeastward.

Plot of 00 UTC rawinsonde data from Reno, Nevada [click to enlarge]

Plot of 00 UTC rawinsonde data from Reno, Nevada [click to enlarge]

Iceberg near Innaarsuit, Greenland

July 20th, 2018 |

Landsat-8 False Color RGB image swaths, zoomed in to show the iceberg near Innaarsuit, Greenland [click to enlarge]

Landsat-8 False Color RGB image swaths, zoomed in to show the iceberg near Innaarsuit, Greenland [click to enlarge]

Landsat-8 False Color Red-Green-Blue (RGB) images viewed using RealEarth (above) is zoomed in (final image) to show a large iceberg (snow and ice appear as cyan) near the island community of Innaarsuit, Greenland (shades of light green) on 20 July 2018. Media stories about this iceberg can be found here and here.

County Fire in central California

July 1st, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and Shortwave Infrared (3.9 µm, right) images, with airport identifiers plotted in yellow [click to play animation | MP4]

The County Fire began burning in central California (northwest of Sacramento) around 2112 UTC or 2:12 pm local time on 30 June 2018 — GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above) showed the smoke plume and thermal anomaly or “hot spot” (dark black to red pixels) of the fire during its initial 6.5 hours. Other features of interest in the imagery included reflection of sunlight from solar panel farms as seen here and here, as well as sun glint off the waters of the Sacramento River and the Sacramento-San Joaquin River Delta as seen here.

During the subsequent overnight hours, the thermal signature exhibited on GOES-16 Near-Infrared “Snow/Ice” (1.61 µm), Near-Infrared “Cloud Particle Size” (2.24 µm) and Shortwave Infrared (3.9 µm) images (below) revealed the rapid southward spread of the fire along the Napa/Yolo county line — the fire began in far western Yolo County, and eventually moved into far eastern Napa County. The smaller, less intense fire signature seen just to the northwest was that of the Pawnee Fire.

GOES-16 Near-Infrared

GOES-16 Near-Infrared “Snow/Ice” (1.61 µm, left), Near-Infrared “Cloud Particle Size” (2.24 µm, center) and Shortwave Infrared (3.9 µm, right) images, with airport identifiers plotted in yellow and Napa/Yolo County outlines plotted in blue [click to play animation | MP4]

A toggle between Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images (below) showed the thermal anomaly and bright glow of the County fire at 1043 UTC or 3:43 am local time. Due to ample illumination from the Moon (in the Waning Gibbous phase, at 90% of Full), the smoke plume could be seen drifting southwest over the adjacent waters of the Pacific Ocean — note the shadow cast by the smoke plume upon the fog/stratus deck immediately off the coast.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images, with surface reports plotted in cyan [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images, with surface reports plotted in cyan [click to enlarge]

A toggle between consecutive Suomi NPP VIIRS Day/Night Band (0.7 µm) images (below) showed the change in location of the smoke plume during the ~1 hour and 40 minutes separating the 2 satellite overpasses. The region was on the far western edge of the earlier swath. These images demonstrate the “visible image at night” capability of the VIIRS Day/Night Band.

Suomi NPP VIIRS Day/Night Band (0.7 µm) images [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) images [click to enlarge]

The 00 UTC rawinsonde data from nearby Oakland (below) showed northeasterly winds at altitudes of 1500-2800 meters or 4900-9200 feet.

Plots of rawinsonde data from Oakland, California [click to enlarge]

Plots of rawinsonde data from Oakland, California [click to enlarge]

During the late morning and early afternoon of 01 July, the fire burn scar could be seen beneath the smoke plume on 250-meter resolution Terra and Aqua MODIS False Color Red-Green-Blue (RGB) images viewed using RealEarth (below).

Terra MODIS True Color and False Color RGB images [click to enlarge]

Terra MODIS True Color and False Color RGB images [click to enlarge]

Aqua MODIS True Color and False Color RGB images [click to enlarge]

Aqua MODIS True Color and False Color RGB images [click to enlarge]

===== 03 July Update =====

Landsat-8 False Color RGB image [click to enlarge]

Landsat-8 False Color RGB image [click to enlarge]

A 30-meter resolution Landsat-8 False Color RGB image (above) showed the areal extent of the County Fire burn scar on the morning of 03 July. Pink-colored pixels indicated hot signatures of actively-burning fires. The morning Incident Report listed the fire size at 70,000 acres and 5% containment.

Fog/stratus over Lake Michigan

June 30th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with hourly plots of surface reports [click to play animation | MP4]

As a warm and very humid air mass (surface analyses) moved northward across the relatively cool waters of Lake Michigan on 30 June 2018, GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) revealed complex interactions of the resulting fog/stratus with coastlines and islands — features such as “bow shock waves” and internal reflections of waves off the northern end of the lake could be seen.

A 30-meter resolution Landsat-8 false-color Red-Green-Blue (RGB) image viewed using RealEarth (below) provided a very detailed view of the fog/stratus structure over the northern end of the lake.

Landsat-8 false-color RGB image [click to enlarge]

Landsat-8 false-color RGB image [click to enlarge]

The Aqua MODIS Sea Surface Temperature product at 1734 UTC (below) showed SST values in the middle 60s to around 70ºF across the southern end of Lake Michigan (the southern lake buoy reported a water temperature of 66ºF), transitioning to SST values around 60ºF mid-lake. The northern lake buoy reported a water temperature of 54ºF — much colder than the surface air dew points that were in the low to middle 70s F, which explained the more widespread coverage of lake fog/stratus farther north.

Aqua MODIS Sea Surface Temperature product, with plots of surface and buoy reports [click to enlarge]

Aqua MODIS Sea Surface Temperature product, with plots of surface and buoy reports [click to enlarge]