Eruption of the Cotopaxi volcano in Ecuador

August 14th, 2015

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

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

GOES-13 visible (0.63 µm) images (above; click to play animation) displayed distinct dark-gray ash plumes from 2 separate daytime eruptions of the Cotopaxi volcano in Ecuador on 14 August 2015 (there was also an initial eruption that occurred during the preceding nighttime hours). The asterisk near the center of the images marks the location of the volcano summit. Volcanic ash fall was observed in the capitol city of Quito (station identifier SEQU, located about 50 km or 30 miles north of the volcano), and some flights were diverted due to the volcanic ash cloud.

The corresponding GOES-13 infrared (10.7 µm) images (below; click image to play animation) showed that cloud-top IR brightness  temperatures were as cold a -53º C (orange color enhancement) at 1915 UTC.

GOES-13 infrared (10.7 µm) images [click to play animation]

GOES-13 infrared (10.7 µm) images [click to play animation]

The volcanic cloud features were also easily tracked on GOES-13 water vapor (6.5 µm) images (below; click image to play animation). In fact, note how the signature in the water vapor imagery is more distinctly seen for a longer period of time than on the 10.7 µm infrared imagery.

 GOES-13 water vapor (6.5 µm) images [click to play animation]

GOES-13 water vapor (6.5 µm) images [click to play animation]

The tan-colored volcanic ash cloud was also evident on Aqua MODIS and Suomi NPP VIIRS true-color Red/Green/Blue (RGB) imagery (below), as viewed using the SSEC RealEarth web map server.

Aqua MODIS true-color images [click to enlarge]

Aqua MODIS true-color images [click to enlarge]

Suomi NPP VIIRS true-color image [click to enlarge]

Suomi NPP VIIRS true-color image [click to enlarge]

A comparison of Suomi NPP VIIRS visible (0.64 µm) and infrared (11.45 µm) images is shown below (courtesy of William Straka, SSEC). The coldest cloud-top IR brightness temperature was -72.7º C.

Suomi NPP VIIRS visible (0.64 µm) and infrared (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS visible (0.64 µm) and infrared (11.45 µm) images [click to enlarge]

Ice in Hudson Bay, Canada

August 7th, 2015

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

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

GOES-13 visible (0.63 µm) images (above; click image to play animation; also available as an MP4 movie file) revealed a large amount of ice remaining in southern and eastern portions of Hudson Bay, Canada on 07 August 2015. The ice can be seen “sloshing” back and forth during the day as winds and/or water currents moved it around.

The discrimination of ice vs supercooled water droplet clouds can be made by comparing Terra MODIS true-color and false-color Red/Green/Blue (RGB) images at 1611 UTC (below). On the false-color image, ice (and glaciated clouds with a high concentration of ice crystals at cloud top) appeared as darker shades of red, in contrast to supercooled water droplet clouds which appeared as varying shades of white to cyan.

Terra MODIS true-color and false-color images [click to enlarge]

Terra MODIS true-color and false-color images [click to enlarge]

A Suomi NPP VIIRS true-color image as visualized using the SSEC RealEarth web map server (below) showed the ice at 1800 UTC; even greater detail can be seen in this zoomed-in version of the image.

Suomi NPP VIIRS true-color image [click to enlarge]

Suomi NPP VIIRS true-color image [click to enlarge]


Maps from from the Canadian Ice Service (below) indicated that the concentration of this thick first-year ice (dark green) was still as high as 9/10ths to 10/10ths (red) on 07 August; on 03 August, the ice concentration departure from normal was as high as +9/10ths to +10/10ths (dark blue) in some locations.

Hudson Bay ice concentration [click to enlarge]

Hudson Bay ice concentration [click to enlarge]

Hudson Bay ice stage [click to enlarge]

Hudson Bay ice stage [click to enlarge]

Hudson Bay ice concentration departure from normal [click to enlarge]

Hudson Bay ice concentration departure from normal [click to enlarge]

Himawari-8 true-color imagery

August 6th, 2015
Himawari-8 true-color images (click to play YouTube animation)

Himawari-8 true-color images (click to play YouTube animation)

A sequence of 10-minute interval Himawari-8 true-color Red/Green/Blue (RGB) images covering the period 01 August to 06 August 2015 is shown above (also available as a very large 721 MByte animated GIF, a 66 Mbyte MP4 movie file, or an alternate version here on YouTube). One of the most prominent features seen is Typhoon Soudelor in the West Pacific Ocean, which reached Category 5 Super Typhoon intensity late in the day on 03 August, as indicated in a plot of the Advanced Dvorak Technique intensity estimate from the CIMSS Tropical Cyclones site (below).

Advanced Dvorak Technique (ADT) intensity estimation plot for Super Typhoon Soudelor (click to enlarge)

Advanced Dvorak Technique (ADT) intensity estimation plot for Super Typhoon Soudelor (click to enlarge)

Other features of interest seen during this 6-day animation include hazy-white plumes of urban pollution and/or wildfire smoke streaming eastward off the Asian continent, as well as light brown or tan-colored plumes of blowing dust/sand originating from the interior desert regions.

The Himawari-8 AHI data are provided by the JMA, acquired by NOAA/NESDIS/STAR, and processed at SSEC/CIMSS. The true-color images use information from AHI bands 1, 2, and 3, combined with a customized contrast stretch algorithm. No background image was used.

Wildfires continue in the interior of Alaska

July 25th, 2015

GOES-15 visible (top) and shortwave IR (bottom) images [click to play animation]

GOES-15 visible (top) and shortwave IR (bottom) images [click to play animation]

Wildfires continued to burn across parts of the interior of Alaska during the 22-25 July 2015 period, as is shown in GOES-15 (GOES-West) 0.63 µm visible channel and 3.9 µm shortwave IR images (above; click to play animation; also available as an MP4 movie file). Also of interest is: (1) the diurnal change of intensity and areal coverage of the fire hot spots (darker black to red pixels on the shortwave IR images), with the fires dying down at night, and (2) the change in direction of smoke transport, from westward on 22 July to eastward on 24 July. The switch in smoke transport direction was the result of changing winds associated with a broad area of low pressure moving across Alaska during that period (surface analyses).

A more detailed view of the fire hot spots was provided by 375-meter resolution (mapped onto a 1-km AWIPS grid) Suomi NPP VIIRS 3.74 µm shortwave IR images (below; click to play animation).

Suomi NPP VIIRS shortwave IR images [click to play animation]

Suomi NPP VIIRS shortwave IR images [click to play animation]

Many of the fires were burning in the general vicinity of the Utopia Creek, Indian Mountain airport (station identifier PAIM); a time series of surface observation from that site (below) showed that visibility was 1 mile or less due to smoke at times on 25 July.

Time series of surface observation from Utopia Creek, Indian Mountain airport [click to enlarge]

Time series of surface observation from Utopia Creek, Indian Mountain airport [click to enlarge]

Daily composites of Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images viewed using the SSEC RealEarth web map server are shown below.

Suomi NPP VIIRS true-color images [click to enlarge]

Suomi NPP VIIRS true-color images [click to enlarge]