Meteosat « CIMSS Satellite Blog

Tropical Cyclone Giovanna (12S)

February 13th, 2012

Meteosat-7 10.8 µm IR images

EUMETSAT Meteosat-7 10.8 µm IR images from the CIMSS Tropical Cyclones site (above) showed the formation of a well-defined eye as Tropical Cyclone Giovanna (12S) intensified from a Category 3 to a Category 4 storm over the Indian Ocean late in the day on 12 February 2012.

Tropical Cyclone Giovanna maintained a Category 4 intensity as it approached the island nation of Madagascar on 13 February, with the diameter of the eye contracting somewhat on IR imagery as Giovanna was undergoing an eyewall replacement cycle (below).

Meteosat-7 10.8 µm IR images

A few hours prior to landfall, a timely overpass of the EUMETSAT Metop-A satellite allowed a nice view of the surface wind structure using ASCAT scatterometer winds (below).

Meteosat-7 10.8 µm IR images + MetOp-A ASCAT scatterometer surface winds

As the tropical cyclone approached the eastern coast of Madagascar, the erosion of the eastern semicircle of the inner eyewall of Giovanna could be seen in the MIMIC-TC product (below).

MIMIC-TC microwave product

Posted in Meteosat, Satellite winds, Tropical cyclones | No Comments »

Large outbreak of Saharan dust over the eastern Atlantic Ocean

February 7th, 2012

EUMETSAT Meteosat-9 0.635 µm visible channel images (click image to play animation)

McIDAS images of EUMETSAT Metosat-9 0.635 µm visible channel images (above; click image to play animation) showed a very large outbreak of airborne Saharan dust streaming off the continent of Africa and moving west-southwestward out over the adjacent waters of the eastern Atlantic Ocean on 07 February 2012. In addition, a pair of long von Karman vortex streets can be seen moving southwestward from the Cape Verde islands.

While the viewing angle was more extreme, the Saharan dust could also be seen on GOES-13 0.63 µm visible channel images (below).

GOES-13 0.63 µm visible channel images + surface reports

The emergence of this Saharan dust over water can be seen to occur around 00:00 UTC on 06 February on the Meteosat-9 Saharan Air Layer tracking product (below).

EUMETSAT Meteosat-9 Saharan Air Layer tracking product

Posted in GOES-13, Meteosat | No Comments »

“Sting Jet” signature associated with a high wind event in Scotland

January 3rd, 2012

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

A rapidly intensifying mid-latitude cyclone (named “Cyclone Ulli” by the Europeans | surface analysis) was responsible for a high wind event as it moved over Scotland on 03 January 2012. A sequence of EUMETSAT Meteosat-9 7.35 µm water vapor channel images (above; click image to play animation) revealed two notable signatures: (1) the formation of a pronounced area of warm/dry water vapor brightness temperatures (bright yellow to orange color enhancement) over the open water north of Ireland, which indicated a strongly forced region of rapidly descending middle-tropospheric air, and (2) a classic “Sting Jet” signature (Monthly Weather Review | Wikipedia) which then moved eastward across Scotland. Just to the south of the sting jet signature, a wind gust of 78 knots (90 mph) was recorded at Glasgow at 08:20 UTC, followed by a wind gust of 70 knots (81 mph) at Edinburgh at 08:50 UTC. There were additional reports of wind gusts in excess of 87 knots (100 mph) at non-METAR sites in Scotland.

The Sting Jet signature can also be seen in EUMETSAT Meteosat-9 10.8 µm IR images (Animated GIF | QuickTime movie) and EUMETSAT Meteosat-9 0.635 µm visible channel images (Animated GIF | QuickTime movie).

A comparison of 1-km resolution NOAA-19 0.63 µm visible channel and 10.8 µm IR channel images at 12:54 UTC (below) showed the structure of the cyclone as it was centered over the North Sea between the British Isles and Norway.