Suomi NPP VIIRS visible and IR images of the eye of Tropical Cyclone Funso

On 24 January 2012 NASA renamed the recently-launched NPP satellite (formerly known as the NPOES Preparatory Project)  the Suomi National Polar-orbiting Partnership (or Suomi NPP) in honor of Dr. Verner Suomi, recognized as “the father of satellite meteorology” (see: NASA News | University of Wisconsin News). A comparison of Suomi NPP 375-meter resolution VIIRS 0.640 µm visible channel and 11.450 µm IR channel images (above) showed the eye of Category 4 Tropical Cyclone Funso, which was located in the Mozambique Channel between Africa and Madagascar at 11:02 UTC on 24 January (track of Tropical Cyclone Funso).

On 25 January 2012, another Suomi NPP 375-meter resolution VIIRS 11.450 µm IR image (below) displayed very cold cloud top IR brightness temperatures (as low as -77º C) associated with a large thunderstom complex over Texas — this storm produced hail up to 1.25 inches in diameter (SPC storm reports) and heavy rainfall of up to 9.29 inches at Uhland (NWS Austin/San Antonio Texas Public Information Statement).

Suomi NPP VIIRS 11.450 µm IR image

The corresponding 4-km resolution GOES-13 (GOES-East) 10.7 µm IR image (below) showed much less structure to the cloud top temperature field, with the coldest IR brightness temperature being -70º C.

GOES-13 10.7 µm IR image

MTSAT-1R 10.8 µm IR channel images

MTSAT-1R 10.8 µm IR channel images from the CIMSS Tropical Cyclones site (above) showed Category 1 Tropical Storm Thane (06B) in the Bay of Bengal, moving toward the east coast of India on 28 December 2011.

Contours of 850-200 hPa satellite-derived deep layer wind shear overlaid on MTSAT-1R 6.75 µm water vapor channel images (below) indicated that Thane was in an environment of low wind shear, which favored some intensification prior to making landfall.

MTSAT-1R 6.75 µm water vapor channel images + Deep layer wind shear

It is interesting to note that the MIMIC Total Precipitable Water product (below) showed the northern counterclockwise circulation of Tropical Storm Thane and the southern clockwise circulation of Tropical Storm Four (04S) — each drawing moisture from the Inter-Tropical Convergence Zone (ITCZ).

MIMIC Total Precipitable Water product

===== 30 December Update =====

Tropical Storm 04 S intensified in a similar low wind shear environment, becoming Tropical Cyclone Benilde in the South Indian Ocean. Benilde was forecast to intensify, with wind gusts up to 140 knots. Meteosat-7 visible/shortwave IR images with an overlay of ASCAT scatterometer surface winds (below) showed the structure of Benilde.

Meteosat-7 visble/shortwave IR imagery + ASCAT surface winds

MTSAT-1R 10.8 µm IR images (click image to play animation)

MTSAT-1R 10.8 µm IR images from the CIMSS Tropical Cyclones site (above; click image to play animation) showed a fairly compact cluster of cold convective cloud tops associated with Tropical Storm Washi as it moved westward toward the Philippines during the 15-16 December 2011 period.

A closer view using MIMIC microwave imagery (below) also showed a relatively small area of enhanced brightness temperatures (representing heavy precipitation) crossing Mindanao Island in the southern Philippines on 16 December.

MIMIC microwave imagery

However, AWIPS images of the MIMIC Total Precipitable Water (TPW) product (below; click image to play animation) revealed that Tropical Storm Washi was embedded within a long fetch of very rich tropical moisture, with TPW values in excess of 60 mm or 2.4 inches (darker red color enhancement). This abundance of moisture helped to fuel over 10 hours of heavy rainfall, which resulted in widespread flash flooding and reports of over 900 deaths in the Philippines.

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

GOES-11 0.65 µm visible channel images + ship reports

According to the National Hurricane Center, on 20 November 2011 Tropical Storm Kenneth became the latest-forming named tropical storm in the eastern North Pacific basin since Hurricane Winnie formed on 04 December 1983. GOES-11 0.65 µm visible channel images from the CIMSS Tropical Cyclones site (above) showed a well-defined circulation, with a ship report of tropical storm force winds north of the storm center.

The corresponding GOES-11 10.7 µm IR images (below) showed a trend of increasing convection withing the northern semicircle of the storm.

GOES-11 10.7 µm IR images + ship reports

AWIPS images of the MIMIC Total Precipitable Water (TPW) product (below; click image to play animation) indicated that TPW values associated with Tropical Storm Kenneth were in the 50-60 mm range (darker orange colors), as rich moisture was sill in place along the Inter-Tropical Convergence Zone (ITCZ) / Monsoon Trough.

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

======== 21 November Update ========

GOES-15 0.63 µm visible images (click image to play animation)

Kenneth was upgraded to a Hurricane on 21 November. GOES-15 0.63 µm visible channel images (above; click image to play animation) showed a ragged eye forming as curved convective bands wrapped around the center of the tropical cyclone. Kenneth was able to intensify in part because it was in an environment that possessed uncharacteristically low values of deep layer wind shear (below).

GOES-11 10.7 µm IR image + deep layer wind shear

======== 22 November Update ========

GOES-15 0.63 µm visible channel images (click image to play animation)

Hurricane Kenneth strengthened to a Category 4 storm on 22 November, becoming the most intense major hurricane to form so late in the season in the satellite era. GOES-15 0.63 µm visible channel images (above; click image to play animation) showed the well-defined eye of Kenneth.

EUMETSAT Meteosat-9 10.8 µm IR images

A sequence of EUMETSAT Meteosat-9 10.8 µm IR images at 6-hour intervals (above) showed the development of an unusual tropical cyclone over the western Mediterranean Sea during the 06 November – 08 November 2011 time period.

The tropical cyclone was designated “01M” in a bulletin issued by NOAA/NESDIS Satellie Analysis Branch at 18:19 UTC on 07 November:

Wind speeds were estimated to have reached 45 knots according to various satellite analysis techniques.

Shown below is a comparison of EUMETSAT Meteosat-9 0.64 µm visible channel images at 12:00 UTC on 07 November and 08 November.

EUMETSAT Meteosat-9 0.64 µm visble channel images at 12:00 UTC on 07 and 08 November

GOES-13 0.63 µm visible channel images + ASCAT scatterometer surface winds

Tropical Storm Rina rapidly intensified (CIMSS ADT plot) to hurricane intensity off the coast of Honduras on 24 October 2011 — GOES-13 0.63 µm visible channel images with an overlay of ASCAT scatterometer surface winds from the CIMSS Tropical Cyclones site (above) showed that Hurricane Rina exhibited a central dense overcast early in the day, with convective bursts near the center of the circulation.

A longer animation of GOES-15 10.7 µm IR channel images (below; click image to play animation) revealed a number of convective bursts, with large areas of the central dense overcast exhibiting cloud top IR brightness temperatures of -80ºC or colder (violet color enhancement).

GOES-15 10.7 µm IR channel images (click image to play animation)

AWIPS images of the MIMIC Total Precipitable Water (TPW) product (below; click image to play animation) suggested that Hurricane Rina may have been tapping moisture from the Eastern Pacific Ocean Intertropical Convergence Zone / Monsoon Trough.

MIMIC Total Precipitable Water product + tropical surface analysis (click image to play animation)

It is interesting to note that an increasing pressure gradient between high pressure located over the Gulf of Mexico and the deepening circulation of Hurricane Rina was beginning to enhance the intensity of dry Tehuano gap winds flowing southward into the Gulf of Tehuantepec (below).

MIMIC TPW + Tropical surface analysis + ASCAT scatterometer surface winds

===== 25 October Update =====

NOAA-16 false color Red/Green/Blue (RGB) image

On 25 October 2011, widespread high altitude cirrus “transverse banding” was seen along the western periphery of Hurricane Rina on a 1-km resolution NOAA-16 false color Red/Green/Blue (RGB) image (above), created using AVHRR visible channels 1 (0.63 µm) and 2 (0.86 µm) along with IR channel 4 (10.8 µm).

4-km resolution GOES-13 6.5 µm “water vapor channel” images (below; click image to play animation) showed that Hurricane Rina was a prolific producer of transverse banding during much of the day. The GOES-13 satellite had been placed into Rapid Scan Operations (RSO) mode, providing images as often as every 5-10 minutes.

GOES-13 6.5 µm water vapor channel images (click image to play animation)

1-km resolution GOES-13 0.63 µm visible channel RSO images (below; click image to play animation) revealed the formation of a well-defined eyewall during the afternoon hours.

GOES-13 0.63 µm visible channel images (click image to play animation)

GOES-15 10.7 µm IR images (click image to play animation)

GOES-15 10.7 µm IR images (above; click image to play animation) showed a large area of very cold cloud top IR brightness temperatures associated with Tropical Storm Jova over the East Pacific Ocean on 07 October 2011. Embedded within the large region of cloud top IR temperatures colder than -80º C (light purple color enhancement) were smaller areas that exhibited cloud top IR temperatures of -90º C or colder (dark purple color enhancement) — and the coldest cloud top IR brightness temperature seen was -94.65º C at 09:30 UTC. It is unusual to see cloud top IR brightness temperatures of -90º C or colder on 4-km resolution GOES IR imagery.

===== 10 October Update =====

A comparison of GOES-11 (GOES-West), GOES-15, and GOES-13 (GOES-East) visible channel images (below) showed the eye of Category 3 Hurricane Jova on 10 October 2011. Note how the difference in satellite viewing angle produces very different eyewall illumination characteristics.

GOES-11, GOES-15, and GOES-13 visible channel images

GOES-15 is scheduled to replace GOES-11 as the operational GOES-West satellite in December 2011.

GOES-13 Visible images (click image to play animation)

Hurricane Ophelia, the fourth hurricane of the north Atlantic tropical season, is pictured above near peak intensity as it moves over the open waters of the Atlantic Ocean, northeast of Hispaniola (which island is visible in the southwest corner of the image loop). The hurricane displays a circular central dense overcast region around a eye in which one might infer the presence of small-scale vortices. Several factors argue for weakening with Ophelia. Note in the animation the motion of the cirrus clouds entering the frame from the west. These high-level winds suggest an increase the shear over Ophelia, and in fact the convective distribution around the storm shows an asymmetry with more convection east of the center. Further, Ophelia’s projected track takes it across a region of ocean that is cooler following the passage of major Hurricane Katia earlier in September. This cool wake limits the energy available to subsequent storms like Ophelia. This loop toggles between images retrieved from the CIMSS Tropical Weather website, showing an enhanced infrared image and a mapping of the sea surface temperatures over the Atlantic in which the wake of Katia is plain. Observations from AVHRR confirm the existence of the cooler SSTs ahead of Ophelia.

The vigor of the convection within a hurricane can be measured by the number of overshooting tops within the circulation. This plot, for example, shows a weakening in Katia as the number of overshooting tops dropped on 2 September. Overshooting tops can be inferred by differencing the 10.7 µm and 6.5 µm channels on the GOES imager. This animation shows only occasional evidence of overshooting tops. Visible imagery from GOES-15 shows evidence of a few overshoots possibly north of the center, and in a spiral band east of the center. A very oblique view from GOES-11 suggests a similar distribution to the overshoots, but also shows a mostly smooth cirrus canopy above the hurricane. The number of overshoots should decrease as Ophelia moves over the cooler waters to its north.

Added: This POES AVHRR Infrared image, showing half of the storm, shows cloud tops as cold as -77 C, but little in the way of overshooting tops. A comparison of this same POES AVHRR IR image (viewed using McIDAS)  with the corresponding POES AVHRR visible image (below) nicely shows the curved convective band that was wrapping around they eye of Hurricane Ophelia.

POES AVHRR 10.8 µm IR and 0.63 µm visible channel images

GOES-15 0.63 µm visible channel images (click image to play animation)

GOES-15 0.63 µm visible channel images  (above; click image to play animation) showed the rather small but very distinct eye of Category 4 Hurricane Hilary in the Eastern North Pacific Ocean on 23 September 2011. GOES-15 (the newest in the series of GOES N/O/P satellites, launched and tested in 2010) is scheduled to replace GOES-11 as the operational GOES-West satellite in December 2011.

During this same time period on 23 September, the GOES-11 satellite was placed into Super Rapid Scan Operations (SRSO) mode, providing bursts of data at 1-minute intervals. Magnified versions of GOES-11 0.65 µm visible channel images (below; click image to play animation; also available as a QuickTime movie) revealed that at times there were multiple mesovortices within the eye of Hurricane Hilary. Larger-scale (zoomed-out) views of GOES-11 SRSO Water Vapor, Visible, and IR channel images are available from CIRA/RAMMB.

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

MTSAT-2 10.8 µm IR channel images (click image to play animation)

MTSAT-2 10.8 µm IR channel images (above; click image to play animation) showed Category 4 Typhoon Roke as it approached Japan during the 19 September – 20 September 2011 period. Roke exhibited a well-defined eye during this time. Massive evacuations were urged by the Japanese government as this strong tropical cyclone approached major population centers in southern Japan.

On an MTSAT-2 IR image with surface and ship reports plotted from the CIMSS Tropical Cyclones site (below), the large radius of strong winds could be seen from the ship report of 50 knots a fair distance east of the storm center.

MTSAT-2 IR image + surface and ship reports

MTSAT-2 0.72 µm visible channel images (below; click image to play animation) showed the eye on 20 September — and there was a hint of meso-vortices within the eye of Roke on the 05:01 UTC visible image.

MTSAT-2 0.72 µm visible channel images (click image to play animation)