Fire signatures following a large explosion in Beirut, Lebanon

August 4th, 2020 |

Suomi NPP VIIRS Day/Night Band (0.7 µm), Near-Infrared (1.61 µm and 2.25 µm), Shortwave Infrared (3.75 µm) and Active Fires product (credit: William Straka. CIMSS) [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm), Near-Infrared (1.61 µm and 2.25 µm), Shortwave Infrared (3.75 µm) and Active Fires product (credit: William Straka. CIMSS) [click to enlarge]

A sequence of Suomi NPP VIIRS Day/Night Band (0.7 µm), Near-Infrared (1.61 µm and 2.25 µm), Shortwave Infrared (3.75 µm) and Active Fires product at 2335 UTC on 04 August 2020 (above) showed nighttime reflective and thermal signatures of the fire that was burning about 8.5 hours following a large explosion that occurred at 1508 UTC in Beirut, Lebanon.

Plots of Spectral Response Functions (SRFs) for similar spectral bands on the GOES-R series ABI instrument (1.61 µm, 2.24 µm and 3.9 µm) are shown below — note that the 1.61 µm and 2.24 µm SRF curves are located close to the peak emitted radiance of very hot features such as large fires.

Plots of Spectral Response Functions for GOES-R series ABI 1..61 µm, 2.24 µm and 3.9 µm spectral bands [click to enlarge]

Plots of Spectral Response Functions for GOES-R series ABI 1..61 µm, 2.24 µm and 3.9 µm spectral bands (credit: Mat Gunshor, CIMSS) [click to enlarge]

EUMETSAT Meteosat-8 Visible (0.8 µm) images (below) showed a subtle signature of the explosion cloud as it slowly spread out to the northwest, west and southwest before sunset. Station identifier OLBA is Beirut  Rafic Hariri International Airport.

Meteosat-8 Visible (0.8 µm) images [click to enlarge]

Meteosat-8 Visible (0.8 µm) images [click to enlarge]

VIIRS Today Website is live

August 4th, 2020 |

VIIRS Today imagery from 3 August (Daytime, left, True Color [Bands 1, 4, 3 from VIIRS] and False Color [Bands 7, 2, 1 from VIIRS] from Suomi NPP; Day Night Band imagery from NOAA-20, right)

CIMSS has hosted the MODIS Today website for many years.  Its follow-on, the VIIRS Today has gone live as of 4 August 2020.

As with MODIS today, the USA is subdivided into 8 sectors, and imagery on a 2-km, 1-km and 250-m grid is provided, even though VIIRS’ best resolution at nadir is 375 m (and 750 m for the Day Night Band).

The images above show True-Color and False Color imagery from Suomi NPP on shortly after noon on 3 August over the northeast United States, along with Day Night Band Imagery from NOAA-20, also from (the early morning of) 3 August, shortly before the Full Moon.

VIIRS Today does have an archive going back several years.  The website allows you to choose either Suomi-NPP or NOAA-20 data (links at the page will also show you today’s Suomi-NPP and NOAA-20 orbital passes), and you can view True Color Imagery (combining channels only in the visible part of the electromagnetic spectrum), False-Color Imagery (combining visible and near-infrared information) or (unique to VIIRS) Day Night Band Imagery.  There is also a link to a webpage showing the Moon Phase.

The image below, downloaded from VIIRS Today, shows the NOAA-20 Day Night Band composite from the morning of 4 August 2020 (link).

NOAA-20 Day Night Band image composite, 4 August 2020 (Click to enlarge)