MTSAT-2 visible (daytime) and IR (night-time) images

A sequence of MTSAT-2 0.675 µm visible channel images (during daytime) and 10.8 µm IR channel images (during the night) revealed the signature of what could be a “midget” tropical cyclone which was moving westward across the western Pacific Ocean during the 17 July – 19 July period (above; click image to play animation).

MTSAT-2 6.75 µm water vapor channel images with overlays of satellite wind derived deep-layer wind shear from the CIMSS Tropical Cyclones site (below; click image to play animation) showed that the region near 21º North latitude 130º East longitude was experiencing generally light to moderate northeasterly wind shear during this time period.

MTSAT-2 water vapor images + deep layer wind shear

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MIMIC Total Precipitable Water product (click image to play animation)

Abundant moisture associated with a strong tropical wave (18 UTC surface analysis) fueled strong thunderstorms which produced record-setting rainfall at San Juan, Puerto Rico on 18 July 2013. AWIPS images of the MIMIC Total Precipitable Water (TPW) product (above; click image to play animation) showed the westward motion of the tropical wave, which exhibited TPW values greater than 50 mm or 2.0 inches (darker orange color enhancement) over a broad area — in fact, TPW values in the vicinity of Puerto Rico reached 60 mm or 2.4 inches on 18 July. Much drier air with significantly lower TPW values (30-35 mm or 1.2-1.4 inches, cyan to darker blue color enhancement) followed in the wake of the tropical wave passage; this dry air was likely the leading edge of a westward pulse of the Saharan Air Layer or SAL (real-time SAL images).

McIDAS images of 4-km resolution GOES-13 10.7 µm IR channel data (below; click image to play animation) showed numerous clusters of thunderstorms with very cold cloud top IR temperatures — IR brightness temperature values were as cold as -82º C (violet color enhancement) at 17:10 UTC.The location of San Juan is marked by the ‘*‘ symbol on the images.The GOES-13 satellite had been placed into Rapid Scan Operations (RSO) mode, providing images as frequently as every 5-10 minutes.

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

A 1-km resolution POES AVHRR 12.0 µm IR image (below) showed a strong thunderstorm beginning to move over the far eastern end of Puerto Rico at 19:35 UTC.

POES AVHRR 12.0 µm IR image (with METAR surface reports)

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GOES-13 false-color Red/Green/Blue (RGB) image

Tungurahua is an active stratovolcano in Ecuador (Wikipedia); a Landsat-8 false-color image showed the partially snow-covered dome of the volcano on 13 July 2013. On the following day, the Washington Volcanic Ash Advisory Center issued a volcanic ash advisory due to an explosive eruption that occurred at 11:51 UTC on 14 July 2013. A GOES-13 false-color Red/Green/Blue (RGB) image created using the NOAA/CIMSS GOES-R Volcanic Ash Detection Algorithm (above) highlighted a warm thermal anomaly and a volcanic cumulonimbus (based upon very rapid cloud top cooling rates and cold IR brightnesss temperature values) minutes after the eruption began — during the “11:45 UTC” GOES-13 image, the satellite was actually scanning the region of the volcanic eruption at 11:58 UTC.

GOES-15 (left), GOES-12 (center), and GOES-13 (right) visible images

A comparison of the early stages of the volcanic cloud as viewed from GOES-15 (GOES-West), GOES-12 (GOES-South America), and GOES-13 (GOES-East) is shown with visible channel images (above) and IR channel images (below). The actual times that each of the satellites were scaning the region of the volcanic eruption are noted in the labels, and the images are shown in the native projection for each individual satellite.

The GOES-13 satellite was the first to detect to volcanic cloud, since it was scanning the area at 11:58 UTC (about 7 minutes after the beginning of the eruption). The oblique viewing angle from the GOES-15 satellite helped to highlight the darker gray appearance of the ash-laden volcanic cloud, and reveal the long shadow being cast to the west of the tall feature (estimated to be as high as 45,000 feet above ground level). The volcanic cloud appeared largest on the GOES-12 images due to the more direct viewing angle, as well as the later scan time.

GOES-15 (left), GOES-12 (center), and GOES-13 (right) IR images

Animations depicting the volcanic cloud evolution are shown using GOES-12 0.65 µm visible channel, 6.5 µm water vapor channel, and 10.7 µm “IR window” channel images (below). Since a large amount of water vapor is usually exhaled during such explosive eruptions, the extent of the volcanic cloud can be more easily followed on the water vapor channel images.

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

GOES-12 6.5 µm water vapor channel images (click image to play animation)

GOES-12 10.7 µm IR channel images (click image to play animation)

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Landsat-8 and GOES-13 views of Convection over Southern Wisconsin

The SSEC Data Center has started ingesting Landsat-8 data, and serving the data up as McIDAS AREA files via ADDE. The image above compares Landsat-8 visible imagery (in the blue part of the visible — near 0.50 µm) that has been scaled down by a factor of 6 from the native 30-m resolution with GOES-13 visible imagery that has been magnified by a factor of 5 from the nominal 1-km resolution. A full-resolution image from Landsat-8 of the convective cell just southeast of Ft. Atkinson, WI is shown here.

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