Blowing Dust over northern Montana

May 24th, 2017 |

GOES-16 Visible Imagery (0.64 µm) from 1707 through 1802 UTC on 24 May 2017 (Click to enlarge)

GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing

The strong pressure gradient around a Low Pressure system over Alberta and Saskatchewan caused strong winds across northern Montana on 24 May 2017, and blowing dust was the result, especially in Hill and Blaine Counties. The visible animation, above, from 1707 to 1802 UTC on 24 May, shows a faint hazy signature along the border of Canada.  The emphasis is on the word ‘faint’ — it is very difficult to pick out the signature unless you know it’s there already  (Thanks to MIC Tanja Fransen at WFO Glasgow for alerting us to this event).  The ‘Blue’ Visible band animation (below) similarly shows the dust, but it is not distinct in this band either.  (*Note* — part of this, of course, is because the default enhancement for visible imagery has been used.  If the ‘low light’ enhancement is applied, the dust signature is more apparent. This visible animation from 1502-2122, courtesy Tanja Fransen, more obviously shows the dust).

GOES-16 Visible Imagery (0.47 µm) from 1707 through 1802 UTC on 24 May 2017 (Click to enlarge)

Brightness Temperature Difference products are routinely available in AWIPS. The Split-Window Difference (SWD), below, shows the difference between the ‘Clean Infrared Window’ (10.33 µm) and the ‘Dirty Infrared Window’ (12.3 µm) (‘Clean’ and ‘Dirty’ referring to a little and more, respectively, water vapor absorption) has historically been used to detect dust: dust will absorb 10.33 µm radiation but it will not absorb 12.3 µm radiation, thus the SWD can highlight regions of dust.  However, that difference is also influenced by water vapor above the dust, and by the type of dust being lofted.

Split Window Difference (10.33 µm – 12.2 µm) from 1707 to 1802 UTC, 24 May 2017 (Click to enlarge)

The Cloud Phase Difference (8.5 µm – 11.2 µm) also can highlight regions of dust, and for this case the signal of dust was a bit more distinct.

Cloud Phase Brightness Temperature Difference (8.5 µm – 11.2 µm) from 1707 to 1802 UTC, 24 May 2017 (Click to enlarge)

Surface data plotted over the 0.64 µm at 1712 UTC, below, show the strong winds in the region (Here is an image at 1802 UTC). Visibilities in the areas of blowing dust were reported to be near zero.

GOES-16 Visible (0.64 µm) at 1712 UTC and 1700 UTC surface observations (Click to enlarge)

A Terra MODIS true-color Red/Green/Blue (RGB) image at 1745 UTC, below, revealed that the source of some of the most dense dust plumes appeared to be uncultivated fields located north and northeast of Havre.

Terra MODIS true-color RGB image (Click to enlarge)

Terra MODIS true-color RGB image (Click to enlarge)

(Added: Stuart Lawrence, south of Rosetown in west-central Saskatchewan, tweeted out this video that showed the dust storm there. He reported winds up to 98 km/hour). Here is another image of the dust in Saskatchewan.

The GOES Aerosol/Smoke Products (GASP) showed a noticeable signal for this dust. Here is a large-scale animation from 1315-2145 UTC, with a closer view from 1015-2345 UTC here)

GOES-16 daytime and nighttime images of the West Mims Fire in Georgia

April 25th, 2017 |

GOES-16 Blue Visible (0.47 µm, top), Red Visible (0.64 µm, center) and Shortwave Infrared (3.9 µm, bottom) images, with hourly surface plots in yellow [click to play animation]

GOES-16 “Blue” Visible (0.47 µm, top), “Red” Visible (0.64 µm, center) and Shortwave Infrared (3.9 µm, bottom) images, with hourly surface plots in yellow [click to play animation]

** The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. **

A daytime comparison of GOES-16 ABI “Blue” Visible (0.47 µm), “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above; also available as an MP4 animation) displayed the smoke plume and “hot spots” (black to yellow to red pixels) associated with the West Mims Fire that was burning in far southeastern Georgia on 25 April 2017 (this fire complex had been burning since 06 April, during which time the drought conditions had been worsening across that region). Downwind of the fire, in far northeastern Florida, smoke reduced the surface visibility to 2 miles at Jacksonville and 5 miles at Fernandina Beach.

During the subsequent nighttime hours — as the fires were beginning to decrease in both intensity and areal coverage — a comparison of “Snow/Ice” Near-Infrared (1.61 µm), “Cloud-Top Phase” Near-Infrared (2.24 µm) and Shortwave Infrared (3.9 µm) images (below; also available as an MP4 animation) showed that a bright glow from the most intense fires was evident in both of the Near-Infrared spectral bands.

GOES-16

GOES-16 “Snow/Ice” Near-Infrared (1.61 µm, top), “Cloud-Top Phase” Near-Infrared (2.24 µm, center) and Shortwave Infrared (3.9 µm, bottom) images, with hourly surface plots in yellow [click to play animation]

Although the spatial resolution of the 1.61 µm Band 5 is 1 km (at satellite sub-point) versus 2 km for the 2.24 µm Band 6, the bright nighttime fire signature was more defined on the 2.24 µm imagery; this is explained by examining a plot of the Spectral Response Function (SRF) for each band (below; courtesy of Mat Gunshor, CIMSS). For a very hot fire target — represented by the red 1200 K line — the 2.24 µm Band 6 SRF is located near the peak of the 1200 K curve, so more of the fire-emitted radiance can be sensed by Band 6 (in spite of its lower spatial resolution).

Spectral Response Function plots for GOES-16 ABI Band 5 (1.61 µm), Band 6 (2.24 µm) and Band 7 (3.9 µm) [click to enlarge]

Spectral Response Function plots for GOES-16 ABI Band 5 (1.61 µm), Band 6 (2.24 µm) and Band 7 (3.9 µm) [click to enlarge]

Fires in eastern Kansas and Oklahoma

April 11th, 2017 |

GOES-16 (left) and GOES-13 (right) Shortwave Infrared (3.9 µm) images [click to play animation]

GOES-16 (left) and GOES-13 (right) Shortwave Infrared (3.9 µm) images [click to play animation]

 ** The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. **

A comparison of GOES-16 and GOES-13 Shortwave Infrared (3.9 µm) images (above) showed numerous fire “hot spot” signatures (black to yellow to red pixels, with red being the hottest) from prescribed burning across the Flint Hills region of eastern Kansas and northeastern Oklahoma on 11 April 2017. Such fires are an annual tradition in this area, required to preserve the tallgrass prairies — for example, over 2.7 million acres were burned during Spring 2016. The 2-km spatial resolution (at satellite sub-point) and 5-minute scan interval of GOES-16 allowed for more accurate detection and monitoring of the fires (compared to the 4-km spatial resolution and 15-30 minute scan interval of GOES-13).

The corresponding Visible GOES-16 (0.64 µm) vs GOES-13 (0.63 µm) images (below) tracked the development and transport of smoke from the fires. Hourly reports of surface visibility (in statute miles) are plotted in red; at Fort Riley, Kansas, smoke reduced the visibility from 10.0 miles at 21 UTC to 1.0 mile at 23 UTC, adversely affecting air quality there.

GOES-16 Visible (0.64 µm, left) and GOES-13 Visible (0.63 µm, right) images, with hourly reports of surface visibility (statute miles, red) [click to play animation]

GOES-16 Visible (0.64 µm, left) and GOES-13 Visible (0.63 µm, right) images, with hourly reports of surface visibility (statute miles, red) [click to play animation]

Grass fires in Kansas, Oklahoma and Texas

March 6th, 2017 |

GOES-16 (left) and GOES-13 (right) 3.9 µm Shortwave Infrared images [click to play MP4 animation]

GOES-16 (left) and GOES-13 (right) 3.9 µm Shortwave Infrared images [click to play MP4 animation]

** The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. **

Widespread grass fires began to burn across parts of southwestern Kansas, northwestern Oklahoma and the Texas Panhandle on 06 March 2017. The fires grew very quickly during the late morning and early afternoon hours, due to strong southwesterly winds (with gusts as high as 67 mph in Oklahoma)  behind a dryline (surface analyses); a cold front then moved southward across the region during the late afternoon and evening hours, bringing strong northerly/northwesterly winds. In a comparison shown above of Shortwave Infrared (3.9 µm) images — 1-minute interval (Mesoscale Sector) 2-km resolution GOES-16 vs. 5-7 minute interval (Rapid Scan Operations) 4-km resolution GOES-13 (also available as a 204 Mbyte animated GIF) — a large fire (the Starbuck Fire) can be seen making a fast northeastward run from Oklahoma into Kansas behind the dryline; then, after the passage of the cold front, the leading edge of that and another large fire turned southward and moved from Kansas back into Oklahoma. Another large fire in the Texas Panhandle (the Perryton Fire) moved rapidly eastward and crossed the border into Oklahoma. At least 7 deaths have resulted from these fires (CNN).

===== 07 March Update =====

The large size of the grass fire burn scars could be seen in comparisons of true-color and false-color Red/Green/Blue (RGB) images from Terra MODIS (1732 UTC), Suomi NPP VIRS (1857 UTC) and Aqua MODIS (1912 UTC) images viewed using RealEarth (below).

Terra MODIS true-color and false-color images [click to enlarge]

Terra MODIS true-color and false-color images [click to enlarge]

Suomi NPP VIIRS true-color and false-color images [click to enlarge]

Suomi NPP VIIRS true-color and false-color images [click to enlarge]

Aqua MODIS true-color and false-color images [click to enlarge]

Aqua MODIS true-color and false-color images [click to enlarge]

The creation of true-color and false-color images such as these will be possible using the ABI spectral bands available on GOES-16 and the GOES-R series of satellites. A separate blog post highlighting other multi-spectral GOES-16 views of these fire burn scars on 07 March  is available here.