Fires burning across eastern Oklahoma

March 23rd, 2011 |
GOES-13 3.9 µm shortwave IR images (click image to play animation)

GOES-13 3.9 µm shortwave IR images (click image to play animation)

AWIPS images of 4-km resolution GOES-13 3.9 µm shortwave IR data (above; click image to play animation) displayed a number of “hot spots” (black to red to yellow  color enhancement) associated with fires that were burning across much of eastern Oklahoma on 23 March 2011. The GOES-13 satellite had been placed into Rapid Scan Operations (RSO) mode to monitor severe convection in the eastern US, providing images as frequently as every 5-10 minutes.

The corresponding 1-km resolution GOES-13 6.3 µm visible channel images (below; click image to play animation) showed the development of a few long southeastward-drifting smoke plumes emanating from some of the larger fires.

 

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

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

A comparison of the 4-km resolution GOES-13 3.9 µm shortwave IR image with the corresponding 1-km resolution POES AVHRR 3.7 µm shortwave IR image (below) demonstrates the advantage of higher spatial resolution for determining the exact location of the hottest fire pixels, as well as for the detection of many of the smaller fires.

GOES-13 3.9 µm shortwave IR image + POES AVHRR 3.7 µm shortwave IR image

GOES-13 3.9 µm shortwave IR image + POES AVHRR 3.7 µm shortwave IR image

These samples of images at both higher temporal resolution and at higher spatial resolution offer a glimpse of the types of improvements that will be available with the ABI instrument on the future GOES-R satellite. 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.

“Plume of unknown etiology” moving over Alaska

March 17th, 2011 |
GOES-11 0.65 µm visible channel images (click image to play animation)

GOES-11 0.65 µm visible channel images (click image to play animation)

McIDAS images of GOES-11 0.65 µm visible channel data (above; click image to play animation) showed an interesting “dark plume” feature that was moving in an arc from far northeastern Russia, across the East Siberian Sea and Chukchi Sea, and finally over far northwestern Alaska on 16 March – 17 March 2011.

When viewed from a more western angle using MTSAT-2 0.73 µm visible channel images (below; click image to play animation), the plume feature (which can be seen moving over far northwestern Alaska in the upper right portion of the images) also exhibited a darker appearance, similar to that seen on the GOES-11 visible imagery. This darker appearance was due to backward scattering of light from the particles within the plume.

 

MTSAT-2 0.73 µm visible channel images (click image to play animation)

MTSAT-2 0.73 µm visible channel images (click image to play animation)

AWIPS images of POES AVHRR 0.86 µm visible channel data (below) provided more of a “direct view from above”,  and revealed that the main body of the plume was basically transparent (allowing details of the sea ice to be seen through the plume).  However, the plume edges appeared to have some vertical structure, being thick enough to cast shadows onto the sea ice below.

POES AVHRR 0.86 µm visible channel images

POES AVHRR 0.86 µm visible channel images

It is interesting to note that this plume feature did not exhibit any notable signature on POES AVHRR 12.0 µm IR images (below).

POES AVHRR 12.0 µm IR images

POES AVHRR 12.0 µm IR images

A series of MODIS true color Red/Green/Blue (RGB) images (below; courtesy of the GINA, University of Alaska) again showed the transparent nature of the main body of the plume feature, except for the thicker edges which  were casting shadows.

MODIS true color Red/Green/Blue (RGB) images (courtesy of University of Alaska, GINA)

MODIS true color Red/Green/Blue (RGB) images (courtesy of University of Alaska, GINA)

Could this feature have been an aged volcanic plume that was being transported aloft over the Arctic? AWIPS images of the MODIS Volcanic Ash Mass Loading product (below) did display a few isolated very small patches exhibiting 1-10 tons per square kilometer of loading at 04:44 UTC on 17 March, but there was no temporal continuity when examining the Ash Mass Loading product before or after this particular time.

MODIS Volcanic Ash Mass Loading product

MODIS Volcanic Ash Mass Loading product

Volcanic Ash Height product

Volcanic Ash Height product

The corresponding MODIS Volcanic Ash Height product (above) indicated that these features were located at an altitude of 3-4 km, while the MODIS Ash Mass Effective Particle Radius product (below) showed values in the 3-5 µm range.

Volcanic Ash Particle Effective Radius product

Volcanic Ash Particle Effective Radius product

However, rather than an aged volcanic ash plume, a more plausible explanation of the feature seen on satellite imagery is the long-range transport of smoke and pollution from industrial sources in northeastern China. A calculation of 96-hour backward trajectories using the NOAA ARL HYSPLIT model (below) indicated that air parcels arriving at 3 points along the plume at an altitude of 6-km had originated within the boundary layer over northeastern China on 13 March. MODIS images showing the thick haze over that region can be found on the US Air Quality “Smog Blog”.

NOAA ARL HYSPLIT back trajectories arriving at  the 4km, 6km, and 8km altitudes

NOAA ARL HYSPLIT back trajectories arriving at the 4km, 6km, and 8km altitudes

Ice breakup in the northern portion of Green Bay

March 15th, 2011 |
MODIS true color Red/Green/Blue (RGB) images

MODIS true color Red/Green/Blue (RGB) images

 

A comparison of 250-meter resolution MODIS true color Red/Green/Blue (RGB) images from the SSEC MODIS Today site (above) shows the breakup of ice in the northern portion of Green Bay, Wisconsin. It can be seen that there is a significant amount of ice motion (due to southwesterly winds) in the time between the 16:52 UTC Terra MODIS image and the 18:35 UTC Aqua MODIS image — and other smaller ice floes can also be seen moving in portions of northern Lake Michigan and southern Lake Superior. Also note that the southwest-to-northeast oriented long-track tornado damage path from the 07 June 2007 severe convection event could still be clearly identified about 100 km to the west of the ice-covered portion of Green Bay.

An animation of McIDAS images of 1-km resolution GOES-13 0.63 µm visible channel data (below; click image to play animation) does show the movement of the ice in the northern portion of Green Bay during the day — but even at an image interval of 15 minutes, errors in the Image Navigation and Registration (INR) tend to produce a bit of “wobble” which makes tracking the ice motion more difficult.

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)

With the next-generation Advanced Baseline Imager (ABI) on the future GOES-R satellite, the spatial resolution of the visible channel will be improved to 500 meters — and the nominal temporal resolution of images over the continental US will be every 5 minutes (although 30-second image intervals will be available for special weather situations). CIMSS participation in GOES-R Proving Ground activities includes the creation of model-simulated ABI visible images, as well as model simulations of 9 other ABI InfraRed (IR) band images.

Subtropical Storm “Ariani” off the coast of Brazil

March 15th, 2011 |

 

GOES-12 0.65 µm visible images (click image to play animation)

GOES-12 0.65 µm visible images (click image to play animation)

 

 

Subtropical Storm “Ariani” developed off the southeast coast of Brazil on 15 March 2011. GOES-12 0.65 µm visible channel images (above; click image to play animation) displayed a number of overshooting tops within the large cloud shield of the disturbance. Some hints of a cyclonic (clockwise in the Southern Hemisphere) circulation could be seen both within the southern flank of the cloud shield, and also just to the southwest of the cloud shield over the open water.

GOES-13 10.7 µm IR images from the CIMSS Tropical Cyclones site (below; click image to play animation) showed a broad area of old cloud tops associated with this feature.

 

GOES-13 10.7 µm IR images (click image to play animation)

GOES-13 10.7 µm IR images (click image to play animation)

 

A GOES-13  IR/Water Vapor difference product (below; click image to play animation) did indicate that there was a large area of overshooting tops (red to violet color enhanced areas). For more information on this product and its application to tropical cyclone intensity analysis, see Olander and Velden, 2009.

 

GOES-13 IR/Water Vapor difference product (click image to play animation)

GOES-13 IR/Water Vapor difference product (click image to play animation)