CIMSS Satellite Blog

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 thick smoke and the hot thermal signature of the Woolsey Fire in southern California on 09 November 2018. On this day it exhibited extreme fire behavior, with the large thermal anomaly or fire “hot spot” (red enhancement) moving rapidly southwestward and reaching the coast. The fires were driven by hot, dry Santa Ana winds, which arrived at Camarillo KCMA around 19 UTC and reached the coast at Point Mugu Naval Air Station KNTD around 22 UTC.

A longer animation of GOES-16 Shortwave Infrared imagery (below) begins at 2115 UTC on 08 November — when a Mesoscale Sector was first positioned over California — and ends 44 hours later at 1725 UTC on 10 November. The first Ventura County fire to show a pronounced thermal signature was the Hill Fire; the earliest appearance of Woolsey Fire pixels that were hot enough to be color-enhanced (yellow) was at 2254 UTC on 08 November (30 minutes after the reported start time of 2224 UTC). The area of hottest (red) pixels then began to increase in coverage and spread toward the southwest after about 06 UTC on 09 November. As was seen in the Visible/Shortwave Infrared animation above, the morning period from 15-19 UTC (7-11 AM local time) was when the fire moved very quickly toward the California coast and the beaches of Malibu. After sunset on 09 November, the area and intensity of hot red/yellow pixels began to decrease, and after 10 UTC (2 AM local time) on 10 November only darker black fire pixels persisted.

GOES-16 Shortwave Infrared (3.9 µm) images [click to play MP4 animation]

A comparison of Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images at 0923 UTC on 10 November (below) also showed a marked reduction in coverage and intensity of hot pixels compared to 15 hours earlier.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images at 0923 UTC [click to enlarge]

The smoke was very dense as it moved out over the adjacent offshore waters of the Pacific Ocean on 09 November, as seen in a sequence of MODIS and VIIRS Visible images (below).

MODIS and VIIRS Visible images [click to enlarge]

VIIRS True Color Red-Green-Blue (RGB) images from Suomi NPP at 2104 UTC and NOAA-20 at 2154 UTC on 09 November (below) also depicted the optically-thick nature of the smoke.

Suomi NPP VIIRS True Color RGB image at 2104 UTC [click to enlarge]

NOAA-20 VIIRS True Color RGB image at 2154 UTC [click to enlarge]

The smoke was so thick that Suomi NPP VIIRS Aerosol Optical Depth values exceeded 1.0 (below), likely due to the VIIRS Cloud Mask product falsely flagging the center portion as “cloud”.

Suomi NPP VIIRS True Color RGB and Aerosol Optical Depth [click to enlarge]

from CIMSS Satellite Blog http://cimss.ssec.wisc.edu/goes/blog/archives/30635