As noted here, CSPP software now includes the ability to show reprojected values of Aerosol Optical Depth, in this case within AWIPS. The AOD from the NOAA-20 afternoon pass on 21 July shows extensive smoke over the Plains of Canada and the northern Plains of the USA. Clean air is confined to the Upper Peninsula (UP) of Michigan. The Day Night band imagery at the same time is more distinct over the UP as well. Note, for example, how easy it is to see Lake Superior compared to Lake of the Woods on the Minnesota/Canada border, or Lake Manitoba.

AOD computation with VIIRS data requires visible bands that give no information at night (the ATBD for VIIRS AOD is here). Day Night Band imagery — with a near-full moon — gives information on smoke distribution based on, as above, how well surface features can be viewed.

VIIRS data from the CIMSS Direct Broadcast site — the source of these AWIPS images — can also be viewed online here.

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VIIRS AOD from the afternoon overpass on 22 July 2024, below, shows a general increase in AOD values over the midwest as the region of relatively clean air over the western Great Lakes shrinks.

Earth-based observations at Madison from this site show the evolution of the particulate matter from 17-22 July. There is an increase an lowering in the particulates over the course of time. In particular, a defined layer near 4 km becomes apparent by 19 July 2024.

The smoke layer is also apparent in the series of small plots shown below, starting high in the atmosphere on 18 July, and descending to around 4 km on 19 July. A lower-layer of particulates was also present on 19-21 July 2024; showers on the 21st likely removed that lower layer.

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GOES-R Satellites also produce the Level 2 product Aerosol Optical Depth. The animation below shows GOES-derived values from 1756-2201 UTC on 22 July. The data are produced every 5 minutes, and the extensive smoke pall is captured.

Four VIIRS overpasses occurred during the 5 hour animation shown above. The four toggles below compare the VIIRS and GOES-R AOD. The VIIRS product on this day shows more coverage. This is likely related to the different cloud masks.

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Next Generation Fire System (NGFS) Alerts (from this website) for the 24 hours including most of 19 July 2024, above, include an alert for a fire on the island of Kauai. Satellite imagery (note the blue button in the alert above) for the time of the alert, below, includes RGB imagery with a box highlighting the detected pixel.

The animation below shows the NGFS Microphysics RGB from 0501 to 0556 UTC (0556 UTC was when NGFS detected the fire, and the detected warm pixels associated with the detected fire are highlighted (in a color related to the computed Fire Radiative Power (FRP)). The box that appears at the end of the animation is a mouse-over feature of the NGFS website that shows information about the fire.

The animation below is of the shortwave infrared imagery (GOES-18 Band 7, 3.9 µm) covering the same time as the NGFS Microphysics above.

A slow animation from the CSPP Geosphere site, below, includes a development (in the Night Microphysics RGB) of signal in the region of the detected fire.

The fire could be viewed from the Federal Aviation Administration webcam at the airfield at Loleau (SOK). The image below shows the camera views at that site. In particular, the northwest view shows the fire, in this case at 2008 UTC on 19 July 2024 (link to webcam).

An animation of the webcam views that show how the fire evolved during the earlier part of the day on 19 July 2024 is below. Note that the smoke plume initially moves inland, but as it ascends higher into the atmosphere, it switches direction and moves out to sea. The 1200 UTC 19 July 2024 Lihue Sounding (from this site; Lihue is on the windward side of Kauai. This fire near Waimea is on the leeward side) shows the tradewinds that are moving the smoke plume offshore. Later in the animation, the amount of smoke increases presumably as winds increase. Clouds are also increasing.

The True-color imagery from GOES-18, above, shows only a very faint smoke plume at the start of the animation. Clouds form over the fire location, and then increase in general as the amount of smoke visible from the satellite increases. The animation belows shows webcam views paired with the closest-in-time GOES-18 image between 1801 and 1901 UTC.

NOAA-20 overflew the fire shortly after 1200 UTC on 19 July. The image below compares Day Night Band imagery on 18 and 19 July.

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I am grateful to Chris Brenchley, WFO Honolulu, for alerting me to the presence of this fire!

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The Community Satellite Processing Package (CSPP) Polar2grid package is being updated and amended. Polar2grid version 3.1 (coming soon to a computer near your desk!) will include the ability to create reprojected images of Aerosol Optical Depth (AOD) and Normalized Difference Vegetation Index (NDVI). The imagery above from AWIPS shows the NOAA-20 AOD near the Lone Rock fire in north-central Oregon. The large values of AOD within the smoke plume are obvious. AOD display values are capped at 1.

Normalized Difference Vegetation Index, shown below in a toggle outlines the region where the fire has been, as an orange region surrounded by yellow to the north and green to the south, with the fire burning to the southeast of the burnscar.

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A zoomed-out toggle of True Color and AOD, below, shows a much large smoke plume (characterized by very large AOD values) over much of Idaho in addition to the smoke plumes from individual fires in the Pacific Northwest.

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GOES-18 True Color imagery (from the CSPP Geosphere website) shows the growth of the Lone Rock fire burn scar over rural north-central Oregon (note the Columbia River at the top of the imagery) from 13 July 2024 (when the fire started in Gilliam County) to 17 July 2024. Careful examination of the True Color imagery shows a fire signal (in the form of a smoke plume) first appearing at 2206 UTC on 13 July 2024. How did NGFS — the Next Generation Fire System — alerts handle this event?

GOES-18 Band 7 shortwave infrared (3.9 µm) imagery, below, from the NGFS Real Earth instance shows 5-minute time steps before the time of the fire. It’s very difficult to determine the fire location from the Band 7 imagery alone. (Important: these GOES data are terrain-corrected; that is, the effects of parallax on the satellite detections have been removed. Thus, the actual location of the satellite pixels where fires are detected is defined with greater precision after applying terrain correction. This blog post (thanks Bill Line!) discusses parallax in surface features).

The NGFS Microphysics RGB (Quick Guide) below, for the same times as the Band 7 imagery above, shows a color change as the fire develops.

A feature of the Real Earth instance for NGFS is that the probe gives you information about the fire, as shown below. The Fire Radiative Power is shown, and the outline color of the pixel is a function of that number — note it changes from orange to red during the animation as the fire intensifies.

The NGFS Alerts Dashboard will continue to detect a fire after it has started (although Alerts are most useful for initial fire detections), as shown below in a screen shot from just before 1400 UTC on 18 July 2024. There are five alerts present for the Lone Rock fire — that has moved into Morrow County by that time — shown in grey. These alerts are labeled as being part of the Lone Rock fire because the fire was known at the time. These alerts are associated with new satellite pixels into which the fire has spread. They can also be due to fires flaring up again after a quiescent period.

Satellite Imagery from one of those alerts is shown below, and I’ve chosen the Day Cloud Fire RGB because it highlights the burn scar that is apparent in the Geosphere True Color imagery above. Recall that the pixels at this website can be queried to determine land surface features — that is shown in the stepped toggle below. The fire at this time was burning in a region of vegetation that included grassland, chapparal and forests.

The CIMSS NGFS website is here. Note that not all functionality shown in this blog post is publicly available.

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