Pyrocumulus clouds and dense smoke from fires in Georgia

June 20th, 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)

McIDAS images of GOES-13 0.63 µm visible channel data (above; click image to play animation) revealed numerous pyrocumulus clouds and large areas of very dense smoke associated with the “Honey Prairie Fire” in the Okefenokee Swamp area of southeastern Georgia on 20 June 2011. The shadows cast by the pyrocumulus towers almost resembled those cast by overshooting tops which are often seen on the anvil tops of severe thunderstorms.

A sequence of 3 AWIPS images of POES AVHRR 0.63 µm visible channel data (below) offered a larger-scale view of the smoke as it drifted eastward across the adjacent offshore waters of the Atlantic Ocean. The shadow cast by a pyrocumulus tower could be seen on the final 21:22 UTC image. As expected, this dense smoke plume exhibited very high Aerosol Optical Depth (AOD) values (see the US Air Quality “Smog Blog” and the NOAA IDEA sites for AOD imagery).

POES AVHRR 0.63 µm visible channel images

POES AVHRR 0.63 µm visible channel images

The 21:22 UTC POES AVHRR 10.8 µm IR image (below) showed that the coldest cloud top IR brightness temperatures at that time were -18º C, which corresponded to an altitude of nearly 24,000 feet using the interactive Skew-T diagram with data from the rawinsonde report from Charleston, South Carolina.

POES AVHRR 10.8 µm IR image + interactive Skew-T for Charleston SC rawinsonde

POES AVHRR 10.8 µm IR image + interactive Skew-T for Charleston SC rawinsonde

 

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On the following day (21 June 2011) the winds were much lighter across the region, so the smoke was not being transported as far eastward over the Atlantic Ocean. In fact, GOES-13 0.63 µm visible channel images (below; click image to play animation) showed that significant amounts of the smoke remained just offshore — so when a sea breeze front began to move inland during the afternoon hours, much of this smoke was brought back inland. For example, at St. Augustine, Florida (surface identifier KSGJ), the surface visibility dropped from 10 miles to 0.75 mile after the surface winds shifted to easterly behind the sea breeze front.

 

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)

 

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A sequence of 250-meter resolution MODIS true color Red/Green/Blue (RGB) images from the SSEC MODIS Today site (below; displayed using Google Earth) showed varying regimes of transport of the thick smoke on 19 June, 20 June, 21 June, and 22 June 2011.

 

MODIS true color RGB images (displayed using Google Earth)

MODIS true color RGB images (displayed using Google Earth)


Smoke dissipation via downdrafts from a collapsing thunderstorm

June 17th, 2011 |
POES AVHRR 10.8 µm IR images

POES AVHRR 10.8 µm IR images

AWIPS images of POES AVHRR 10.8 µm IR data (above) showed a thunderstorm that was moving off the Georgia/Florida coast during the pre-dawn hours on 17 June 2011. Rapidly-warming cloud top IR brightness temperatures indicated that this thunderstorm was quickly dying.

A POES AVHRR false color Red/Green/Blue (RGB) image at 12:36 UTC (below) depicted a well-defined outflow boundary resulting from the downdrafts of the collapsing thunderstorm — and to the east of the storm, the hazy signature of residual smoke from wildfires that had been burning across the region during previous days.

POES AVHRR false color Red/Green/Blue (RGB) image

POES AVHRR false color Red/Green/Blue (RGB) image

McIDAS images of GOES-13 0.63 µm visible channel data (below) showed that a great deal of the smoke east of the storm was apparently dissipated by cleaner downdraft air from the dying convection.

GOES-13 0.63 µm visible channel images

GOES-13 0.63 µm visible channel images

This clearing of the smoke was also apparent on a MODIS true color image from the SSEC MODIS Today site (below).

MODIS true color image

MODIS true color image

For additional images and information, see the US Air Quality “Smog Blog”.

Eruption of the Nabro volcano in Eritrea

June 14th, 2011 |
FY-2E 0.73 µm visible channel images (click image to play animation)

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

The Nabro volcano erupted in the northeast Africa country of Eritrea on 12 June 2011. An oblique view using the Chinese FY-2E satellite (positioned over the Equator at 105º East longitude) 0.73 µm visible channel data (above; click image to play animation) showed the volcanic plume streaming northwestward on 13 June (the Nabro volcano is located near the bottom center of the images. Note that the plume became much brighter on the visible images later in the day, due to forward scattering.

A sequence of EUMETSAT Meteosat-9 7.35 µm “water vapor channel” images (below; click image to play animation) was useful for following the leading edge of the volcanic plume (the volcano summit is circled on the first few images of the animation). The plume moved northward over far northeastern Africa, and eventually curved anticyclonically and passed over the northern Arabian Peninsula on 14 June. It then appeared as if the leading edge of the volcanic plume might have eventually become entrained into a conveyor of isentropic ascent, where moisture began to increase (exhibiting a darker blue color on the water vapor images).

Meteosat-9 7.35 µm water vapor channel images (click image to play animation)

Meteosat-9 7.35 µm water vapor channel images (click image to play animation)

Hurricane Adrian in the East Pacific

June 9th, 2011 |
GOES-12 0.63 µm visible channel images

GOES-12 0.63 µm visible channel images

 

Hurricane Adrian developed into a Category 3 hurricane early in the day on 09 June 2011. McIDAS images of GOES-12 0.63 µm visible channel data (above) initially showed a well-defined eye before it began to get partially obscured by the high clouds of a central dense overcast (CDO).

DMSP SSMIS 85 GHz microwave images from the CIMSS Tropical Cyclones site (below) revealed a distinct eye at 12:09 UTC and 14:56 UTC.

DMSP SSMIS 85 GHz microwave images

DMSP SSMIS 85 GHz microwave images

GOES 10.7 µm IR images (below) also briefly showed a well-defined eye early in the day, which later filled in a bit beneath the CDO as a curved band of cold high clouds began to wrap around the eastern and northern quadrants of the hurricane.

GOES 10.7 µm IR images

GOES 10.7 µm IR images

The circulation of Hurricane Adrian could be clearly seen on an AWIPS image of ASCAT scatterometer winds overlaid on a GOES IR image (below).

ASCAT scatterometer winds (overlaid on GOES IR image)

ASCAT scatterometer winds (overlaid on GOES IR image)

AWIPS images of the MIMIC Total Precipitable Water (TPW) product (below) showed that Adrian was tapping moisture from the Inter-Tropical Convergence Zone (ITCZ) / “Monsoon Trough”, which was located at approximately 10º North latitude over the eastern Pacific Ocean.

 

MIMIC Total Precipitable Water product

MIMIC Total Precipitable Water product

===== 10 June Update =====

Hurricane Adrian intensified to a Category 4 storm on 10 June 2011. 4-km resolution GOES 10.7 µm IR channel images (below; click image to play animation) continued to show a well-defined eye structure.

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

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

A closer view of the eye could be seen using 1-km resolution GOES visible channel images (below; click image to play animation).

GOES visible channel images (click image to play animation)

GOES visible channel images (click image to play animation)

The intensity of Hurricane Adrian was expected to decrease as the storm began to move over colder waters, as seen on an image of the Sea Surface Temperature (SST) analysis (below).

Sea Surface Temperature (SST) analysis

Sea Surface Temperature (SST) analysis