Wildfires in Texas

April 15th, 2011 |
GOES-13 0.63 µm visible channel images (click image to play animation)

GOES-13 0.63 µm visible channel images (click image to play animation)

Large wildfires continued to burn out of control across much of Texas on 15 April 2010. McIDAS images of GOES-13 0.63 µm visible channel data (above; click image to play animation) showed the growth of a number of very long smoke plumes which were fanned out by strong northerly and northwesterly winds in the wake of a cold frontal passage. The GOES-13 satellite had been placed into Rapid Scan Operations (RSO), providing images as frequently as every 5-10 minutes.

MODIS true color Red/Green/Blue (RGB) images from the SSEC MODIS Today site (below; displayed using Google Earth) also showed that a significant dust plume aloft was spreading out southeastward across the region. The blowing dust exhibited a distinct light brown color, in contrast to the light gray color of the smoke plumes.

MODIS true color Red/Green/Blue (RGB) images (displayed using Google Earth)

MODIS true color Red/Green/Blue (RGB) images (displayed using Google Earth)

AWIPS images of POES AVHRR 3.7 µm shortwave IR and 10.8 µm IR window data from the previous evening (below) showed the very large size of some of the fire “hot spots” (black to red to yellow color enhancement on the shortwave IR image) — as well as the fact that some of the fires were so hot that they even exhibited a dark black hot spot signature of the 10.8 µm IR window channel image.

POES AVHRR 3.7 µm shortwave IR + 10.8 µm IR window images

POES AVHRR 3.7 µm shortwave IR + 10.8 µm IR window images

CIMSS participation in GOES-R Proving Ground activities includes making a variety of POES AVHRR images and products available for National Weather Service offices to add to their local AWIPS workstations.

Von Karman vortices south of the Aleutian Islands

April 14th, 2011 |

 

POES AVHRR 0.86 µm visible channel images

POES AVHRR 0.86 µm visible channel images

AWIPS images of POES AVHRR 0.86 µm visible channel data (above) revealed a pair of von Karman vortices streaming southward from the Aleutian Islands of Alaska on 14 April 2011. In this 2-image comparison, note that the cloud features were moving, but the ice in the Bering Sea remained stationary.

An overlay of MADIS low-level atmospheric motion vectors (or “cloud-tracked winds”) indicated that northerly winds across the region were generally in the 20-30 knot range (below).

POES AVHRR visible images + MADIS atmospheric motion vector winds

POES AVHRR visible images + MADIS atmospheric motion vector winds

POES AVHRR Cloud Top Temperature product

POES AVHRR Cloud Top Temperature product

The corresponding POES AVHRR Cloud Top Temperature (CTT) product images (above) indicated that CTT values for these von Karman vortex features were generally in the -10 to -15º C range, while POES AVHRR Cloud Top Height (CTH) product images (below) showed that the tops of the clouds were  around 1-2 km.

POES AVHRR Cloud Top Height products

POES AVHRR Cloud Top Height products

Widespread fires continue in eastern Kansas; resultant smoke pall aloft over Missouri

April 13th, 2011 |

 

POES AVHRR 3.7 µm shortwave IR image

POES AVHRR 3.7 µm shortwave IR image

An AWIPS image of POES AVHRR 3.7 µm shortwave IR data (above) revealed a large number of fire “hot spots” (black to red to yellow pixels) across much of eastern Kansas on 12 April 2011. The majority of these were grassland fires.

On the following day (13 April 2011), a well-defined area of dense smoke aloft could be seen stretching from Missouri into southwestwen Iowa on a MODIS 0.65 µm visible channel image (below).

MODIS 6.5 µm visible channel image

MODIS 6.5 µm visible channel image

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GOES-13 0.63 µm visible channel images (click image to play animation)

GOES-13 0.63 µm visible channel images (click image to play animation)

GOES-13 0.63 µm visible images (above; click image to play animation) showed that the dense smoke feature moved very little during the day. An overlay of NAM12 850 mb winds (below) indicated that light southwesterly winds in the morning transitioned to a more organized southeasterly flow as a low-level cyclonic circulation moved southward across Nebraska into Kansas.

GOES-13 visible images + NAM12 850 mb winds

GOES-13 visible images + NAM12 850 mb winds

A MODIS true color Red/Green/Blue (RGB) image from the SSEC MODIS Today site (below; displayed using Google Earth) provided a better view of the smoke pall aloft as the northern end wrapped around the low-level cyclonic circulation.

MODIS true color RGB image (displayed using Google Earth)

MODIS true color RGB image (displayed using Google Earth)

MODIS Aerosol Optical Depth (AOD) products from the IDEA site (below) showed very high ADO values  (orange to red color enhancement) associated with this smoke feature.

MODIS Aerosol Optical Depth (AOD) products

MODIS Aerosol Optical Depth (AOD) products

Flooding along the Red River in North Dakota

April 11th, 2011 |
MODIS false color RGB image (displayed using Google Earth)

MODIS false color RGB image (displayed using Google Earth)

A MODIS false color Red/Green/Blue (RGB) image from the SSEC MODIS Today site (above; courtesy of Kathy Strabala, CIMSS) showed the areal extent of the unprecedented overland flooding that was occurring along parts of the Red River in North Dakota on 11 April 2011. Spring snow-melt along with recent heavy rainfall were contributing to the flooding. Interstate 29 north of Fargo was closed on the previous day due to rising floodwater covering the roadway.

AWIPS images of 1-km resolution MODIS 0.65 µm visible channel and 2.1 µm near-IR “snow/ice” channel data (below) was also useful for helping to highlight the location of the flooded areas. Both water and frozen lakes appear as very dark features on the 2.1 µm “snow/ice” channel image — but the frozen lakes are brighter white on the visible image.

MODIS 0.65 µm visible image + MODIS 2.1 µm near-IR "snow/ice" image

MODIS 0.65 µm visible image + MODIS 2.1 µm near-IR "snow/ice" image

A comparison of 250-meter resolution MODIS true color and false color RGB images (below) offered a more detailed view of the flooding in the Fargo and Grand Forks areas. The flooded areas exhibited a “muddy” light brown appearance on the true color image. Farther to the west, the still-frozen Devils Lake (whose water level had reached a new record high level) and portions of northeastern North Dakota that still had snow cover (as much as 6 inches remaining on the ground) could also be seen (snow cover and frozen lakes appeared as lighter blue to cyan features on the false color image).

250-meter resolution MODIS true color and false color RGB images

250-meter resolution MODIS true color and false color RGB images