Fires and blowing dust across western Texas

February 27th, 2011

 

MODIS true color Red/Green/Blue (RGB) image (viewed using Google Earth)

MODIS true color Red/Green/Blue (RGB) image (viewed using Google Earth)

 

High winds (gusting to 69 mph at Amarillo, Texas) downed power lines that ignited a number of grassland wildfires across western Texas on 27 February 2011 — according to media reports, these fires destroyed at least 60 homes, burned more than 140,000 acres, and caused an accident on Interstate 20 near Midland, Texas that killed a 5-year-old child. These high winds were also responsible for widespread areas of blowing dust, which reduced surface visibilities in a number of locations. Laredo, Texas recorded a daily high temperature of 103ºF (the first high temperature of 100º F or greater of the year in the US). A MODIS true color Red/Green/Blue (RGB) image from the SSEC MODIS Today site (above, viewed using Google Earth) showed the areas which were affected by blowing dust and smoke plumes from wildfires.

 

A comparison of AWIPS images of 4-km resolution GOES-13 3.9 µm shortwave IR data with the corresponding 1-km resolution MODIS 3.7 µm shortwave IR data (below) demonstrated the improved fire hot spot (red to yellow color enhancement) detection capability provided by higher spatial resolution. On the MODIS image, some of the fire pixels were so hot that they “wrapped around” on the color scale and appeared as white pixels.

MODIS 3.7 µm + GOES-13 3.9 µm shortwave IR images

MODIS 3.7 µm + GOES-13 3.9 µm shortwave IR images

 

An AWIPS comparison of the MODIS 0.65 µm visible channel and the corresponding MODIS 1.38 µm “cirrus detection channel” image (below) showed the utility of the near-IR cirrus detection channel for highlighting the areal coverage of the blowing dust (which showed up as the slightly brighter areas, since this MODIS channel is sensitive to any particles that are efficient scatters of light). At the time of the MODIS image, winds across this region were gusting as high as 46 knots at Pecos (station identifier KPEQ).

 

MODIS 0.65 µm visible image + MODIS 1.38 µm "cirrus detection" image

MODIS 0.65 µm visible image + MODIS 1.38 µm "cirrus detection" image

 

Farther to the north over the Texas Panhandle region, a similar comparison of the 4-km resolution GOES-13 3.9 µm shortwave IR data with the corresponding 1-km resolution MODIS 3.7 µm shortwave IR data (below) again demonstrated the improved fire hot spot (red to yellow color enhancement) detection capability provided by higher spatial resolution.

MODIS 3.7 µm + GOES-13 3.9 µm shortwave IR images

MODIS 3.7 µm + GOES-13 3.9 µm shortwave IR images

 

A similar AWIPS comparison of the MODIS 0.65 µm visible channel and the corresponding MODIS 1.38 µm “cirrus detection channel” image (below) again showed the utility of the near-IR cirrus detection channel for highlighting the areal coverage of the blowing dust. At the time of the MODIS image, winds across this region were gusting as high as 60 knots at Amarillo (station identifier KAMA), where surface visibility was restricted to 1.5 miles.

MODIS 0.65 µm visible image + MODIS 1.38 µm "cirrus detection" image

MODIS 0.65 µm visible image + MODIS 1.38 µm "cirrus detection" image

 

 

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