Wildfires in British Columbia

August 17th, 2018 |

GOES-16

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

A 2-panel comparison of GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above) showed the smoke plumes and thermal anomalies or “hot spots” (darker black to red pixels) associated with a flare-up of wildfires in western British Columbia on 17 August 2018.

A sequence of Shortwave Infrared (3.7 µm) images from Terra / Aqua MODIS and Suomi NPP / NOAA-20 VIIRS (below) revealed the diurnal changes in areal coverage and intensity of the thermal signature of the fires.

Shortwave Infrared (3.7 µm) images from Terra / Aqua MODIS and Suomi NPP / NOAA-20 VIIRS [click to enlarge]

Shortwave Infrared (3.7 µm) images from Terra / Aqua MODIS and Suomi NPP / NOAA-20 VIIRS [click to enlarge]

Toggles between Visible and Shortwave Infrared images from Terra MODIS (1912 UTC), NOAA-20 VIIRS (1950 UTC) ans Suomi NPP VIIRS (2129 UTC) are shown below (note: the NOAA-20 images are incorrectly labeled as Suomi NPP). It is interesting to note the impact that the smoke plume had on the air temperature at Quesnel (CYQZ) — because the smoke layer was optically dense enough (VIIRS True Color image) to significantly reduce incoming solar radiation, the temperature was as much as 14-18ºF (8-10ºC) cooler than Prince George (CYXS) to the north and Williams Lake (CYWL) to the south.

Terra MODIS Visible (0.65 µm) and Shortwave Infrared (3.7 µm) images [click to enlarge]

Terra MODIS Visible (0.65 µm) and Shortwave Infrared (3.7 µm) images at 1912 UTC [click to enlarge]

NOAA-20 VIIRS Visible (0.64 µm) and Shortwave Infrared (3.74 µm) images [click to enlarge]

NOAA-20 VIIRS Visible (0.64 µm) and Shortwave Infrared (3.74 µm) images at 1950 UTC [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) and Shortwave Infrared (3.74 µm) images at 2129 UTC [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) and Shortwave Infrared (3.74 µm) images at 2129 UTC [click to enlarge]

Farther to the east in Alberta, thick smoke caused very poor air quality in cities like Edmonton and Grande Prairie (photo 1 | photo 2). Daily composites of Suomi NPP VIIRS True Color RGB images from 11 August to 17 August (below) revealed the transport of smoke across British Columbia, Alberta and Saskatchewan.

Daily composites of Suomi NPP VIIRS True Color RGB images (with VIIRS fire detections in red), 11-17 August [click to play MP4 | Animated GIF]

Daily composites of Suomi NPP VIIRS True Color RGB images (with VIIRS fire detections in red), 11-17 August [click to play MP4 | Animated GIF]

A time series of surface reports from Edmonton, Alberta covering the period 14-17 August (below) showed that smoke restricted the surface visibility there to 1.5 miles on 15 August and 17 August.

Time series of surface reports from Edmonton, Alberta during the period 14-17 August [click to enlarge]

Time series of surface reports from Edmonton, Alberta during the period 14-17 August [click to enlarge]

===== 19 August Update =====

* GOES-17 images shown here are preliminary and non-operational *

GOES-17 Near-Infrared

GOES-17 Near-Infrared “Cloud Particle Size” (2.24 µm, left) and Shortwave Infrared (3.9 µm, right) images [click to play 81 Mbyte MP4 animation]

A 2-panel comparison of GOES-17 Near-Infrared “Cloud Particle Size” (2.24 µm) and Shortwave Infrared (3.9 µm) images during the 7-day period of 13-19 August (above) showed the diurnal changes in thermal signatures of the ongoing British Columbia wildfires. The nighttime thermal signatures seen on the 2.24 µm images (brighter white pixels) result from the fact that this spectral band is located close to the peak emitted radiance of very hot features such as active volcanoes or large fires (below).

Plots of Spectral Response Functions for ABI Bands 5, 6 and 7 [click to enlarge]

Plots of Spectral Response Functions for ABI Bands 5, 6 and 7 [click to enlarge]

Hurricane Lane in the eastern Pacific Ocean

August 17th, 2018 |

NOAA-20 VIIRS Imagery at 1023 UTC on 17 August 2018. Day Night Band Visible (0.7 µm) and I05 Infrared (11.45 µm) imagery are shown (Click to enlarge)

The active eastern Pacific Hurricane season continues, as Lane has formed. Suomi NPP and NOAA-20 overflew the system early on 17 August 2018. The toggle above, from NOAA-20’s VIIRS Instrument, shows both the Day Night Band 0.70 µm visible Image and the 11.45 µm infrared channels. Lack of lunar illumination means that only Earthglow is making clouds visible; a distinct eye is not present. The step animation below between the NOAA-20 11.45 µm infrared and, 50 minutes later, Suomi NPP’s 11.45 µm Infrared, right at the limb of the scan, also show no distinct eye.

VIIRS I05 11.45 µm Infrared Imagery from NOAA-20 (1023 UTC) and Suomi NPP (1113 UTC) on 17 August 2018 (Click to enlarge)

In fact, however, an eye was likely present at this time. As noted in the National Hurricane Center’s 0900 UTC Discussion (Link), “Recent microwave images show a well-defined low-level eye, but this feature is not yet apparent in geostationary satellite images.”  AMSR-2 (Advanced Microwave Scanning Radiometer 2) estimates of Convective Precipitation and Surface Rainfall in the toggle below (data from 1003 UTC) show a distinct eye.  AMSR-2 is a microwave instrument that flies on JAXA’s GCOM satellite;  microwave views of tropical cyclones are able to penetrate the cirrus shield that is commonly present, revealing important information about the low-level structure of a developing system.

GCOM AMSR-2 estimates of convective precipitation and surface rainfall rates at 1003 UTC on 17 August 2018 (Click to enlarge)

Polar Orbit tracks are available here. For the latest information on Hurricane Lane, refer to the National Hurricane Center or to the CIMSS/SSEC Tropical Weather Website. Imagery from Polar Orbiters are available at this site that shows data from an antenna in Honolulu.

Thank you to William Straka, CIMSS, for the imagery.