“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

Widespread fire activity in Oklahoma

March 11th, 2011
POES AVHRR 0.63 µm visible image + POES AVHRR 3.7 µm shortwave IR image

POES AVHRR 0.63 µm visible image + POES AVHRR 3.7 µm shortwave IR image

AWIPS images of 1-km resolution POES AVHRR 0.63 µm visible and POES AVHRR 3.7 µm shortwave IR data (above) showed a large number of IR “hot spots” (black to red to yellow color enhancement) due to widespread fire activity across southeastern Oklahoma on 10 March 2011. One well-defined smoke plume could be sen streaming southeastward ffrom one of the larger fires.

On the following day (11 March 2011), the POES AVHRR 3.7 µm shortwave IR image again displayed a large number of fire hot spots over that same region.

POES AVHRR 3.7 µm shortwave IR image

POES AVHRR 3.7 µm shortwave IR image

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.

Fire and Ice, as viewed by GOES-11

March 9th, 2011

 

GOES-11 3.9 µm shortwave IR images (click image to play animation)

GOES-11 3.9 µm shortwave IR images (click image to play animation)

 

A fissure eruption on the Kilauea volcano on the island of Hawaii began on 05 March 2011 — and 3 days later, McIDAS images of GOES-11 3.9 µm shortwave IR data (above; click image to play animation) displayed a prominent “hot spot” (yellow to red enhanced pixels) during the day on 08 March 2011.

GOES-11 0.65 µm visible images (below; click image to play animation) showed the hazy summit plume spreading southwestward during the day. This volcanic plume contained high levels of sulphur dioxide (SO2), as seen on an image of OMI total column SO2 (courtesy of NOAA/NESDIS).

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

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

About 3000 miles (4800 km ) to the north, GOES-11 0.65 µm visible images (below; click image to play animation) showed the movement of ice in the Bering Sea west of Alaska. Note that the motion of the ice was toward the northeast early in the animation, but then changed to motion toward the southwest later in the day. Surface winds along with tidal currents in the Bering Sea have an influence on the overall motion of the ice.

 

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

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

The motion of the ice in the Bering Sea could also be seen on a sequence of AWIPS images of POES AVHRR 0.86 µm visible channel data (below).

POES AVHRR 0.86 µm visible images

POES AVHRR 0.86 µm visible images

 

The POES AVHRR Sea Surface Temperature (SST) product (below) indicated that SST values were in the low to middle 30f F (darker blue color enhancement) in the ice-free water south and west of the ice edge.

POES AVHRR Sea Surface Temperature product

POES AVHRR Sea Surface Temperature product

 

Contrails over eastern North Dakota

March 7th, 2011
POES AVHRR 10.8 µm "IR window" image

POES AVHRR 10.8 µm "IR window" image

A pair of interesting “Figure 8” aircraft condensation trails (or “contrails”) could be seen on a 1-km resolution POES AVHRR 10.8 µm “IR window” image over eastern North Dakota on 07 March 2011 (above). The contrails appeared slightly colder (brighter white) than the surrounding snow-covered ground surfaces. These contrail patterns were presumably made by military jets conducting training exercises from nearby Grand Forks Air Force Base.

The contrail patterns were even more apparent on the corresponding POES AVHRR 3.7 µm “shortwave IR” image (below). The contrail features appeared darker on the shortwave IR image due to reflection of solar radiation off the small supercooled water droplets that comprised the cloud features — and their shadows appeared as slightly cooler (brighter white) signatures on the surface.

POES AVHRR 3.7 µm "IR window" image

POES AVHRR 3.7 µm "IR window" image

On the 0.63 µm POES AVHRR visible image (below), the contrail shadows showed up very well as darker features against the bright snow-covered ground. Using an Interactive Image Fader Tool, the distance offset between the contrails themselves (darker features on the shortwave IR image) and their shadows (darker features on the visible image) was quite obvious — this distance offset was due to the fairly low sun angle at this time of the day over North Dakota in early March.

POES AVHRR 0.63 µm visible image

POES AVHRR 0.63 µm visible image

Tip of the hat to Gregg Gallina (NOAA/NESDIS/SAB) for bring this interesting feature to our attention!