Many of the islands in Indonesia have been shrouded in smoke for much of October. RGB composites from Himawari-8, above, for 0200 UTC on each day from 08-26 October 2015 testify to the dense smoke, especially over the island of Borneo. News reports suggest the haze will persist through the end of the year. This is in part due to the strong El Nino event ongoing; El Nino events typically suppress rainfall over the western tropical Pacific basin.

Smoke detection using visible channels, such as those combined in the true color imagery above, is straightforward. At night, however, visible imagery is not available. The animation below shows the difficulty in detecting smoke using infrared imagery. Although parts of the smoke plume show up, the widespread pall of smoke is not captured. Hot spots can be detected using the 3.9 µm (and 2.3 µm) bands on Himawari-8, but viewing the transport of the resultant smoke is a challenge. Except for the VIIRS Day/Night Band imagery from Suomi NPP, then, nighttime smoke detection relies on model output (Source).

The SSEC RealEarth web map server can be used to take a closer look at the islands of Borneo and Sumatra from 20-26 October. Daily comparisons of Suomi NPP VIIRS fire detections and true-color RGB images shown below revealed that although there was a gradual decreasing trend in the number and areal coverage of fires by 26 October, a great deal of smoke still remained over much of the region.

A daily time series plot of weather conditions at the major airport of Kuala Lumpur, below, showed that the surface visibility was often restricted to less than 1 mile during the 20-26 October period.

The Suomi NPP VIIRS instrument contains a day-night sensor that produces useful visible imagery when illuminated by the Moon (and a full Moon occurred on 27 October 2015). The image above from 1837 UTC on 26 October (Courtesy William Straka, SSEC) shows a pall of smoke from Borneo to Sumatra. Thunderstorms are also present over the South China Sea and Borneo. An toggle of the Day Night Band, the 3.9 µm infrared and the 1.6 µm infrared imagery shows that hot spots associated with fires can be detected (enhanced as orange in the 3.9 µm and white in the 1.6 µm), but the associated smoke is mostly undetected in the infrared.

Two sites, one NASA and one NOAA, can give additional information about the smoke. The toggle below, taken from imagery at the NASA site, shows MODIS True-Color imagery, Aeorosol Optical Depth (AOD) (in NASA Worldview, with units) (in cloud-free regions) and retrieved Carbon Monoxide concentrations (in NASA Worldview, with units). AODs are very large, and CO concentrations are off the scale.

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GOES-15 (GOES-West) Infrared (10.7 µm) images (above; also available as an MP4 animation) displayed the formation of a ring of cold eyewall cloud-top IR brightness temperatures (in the -80 to -90º C range, violet colors) during the period of rapid intensification of Hurricane Patricia on 22 October 2015; the storm reached Category 5 intensity around 00 UTC on 23 October. Patricia then continued to intensify, reaching maximum sustained surface winds estimated at 175 knots with a minimum central pressure of 878.4 hPa or 25.94 inches of mercury (making this the strongest tropical cyclone on record for the National Hurricane Center area of responsibility, which is the North Atlantic Ocean and the eastern North Pacific Ocean). The storm weakened somewhat prior to making landfall (although still as a Category 5 hurricane) around 2315 UTC on 23 October.

Multi-day YouTube animations showing the formation of Patricia are available here (0.63 µm visible imagery from GOES-13) and here (10.7 µm infrared imagery from GOES-13). The multi-day location of Patricia’s 850 hPa relative vorticity signature (derived from satellite atmospheric motion vector data) can be seen here.

A plot of the Advanced Dvorak Technique intensity estimate (below) showed the rate of rapid intensification on 22-23 October. At one point Patricia’s central pressure deepened 100 hPa in 24 hours, and 73 hPa in 12 hours, making it the fastest-intensifying tropical cyclone on record in the Western Hemisphere.

GOES-15 Visible (0.63 µm) images (below; also available as an MP4 animation) revealed the small “pinhole” eye of Patricia during rapid intensification on 22 October.

As Patricia was rapidly intensifying from a Category 1 to Category 5 intensity, the tropical cyclone was moving over a region of high Ocean Heat Content (below), and Sea Surface Temperature values were as high as 31º C.

A comparison of Suomi NPP VIIRS Infrared (11.45 µm) and Day/Night Band (0.7 µm) images at 0741 UTC on 23 October is shown below (courtesy of William Straka, SSEC). With ample illumination from the Moon (which was in the Waxing Gibbous phase, at 78% of Full), the “visible image at night” capability of the Day/Night Band provided a detailed view of cloud-top gravity waves surrounding the eye.

A later VIIRS Infrared (11.45 µm) image at 0920 UTC is shown below.

A comparison of GOES-15 (GOES-West) and GOES-13 (GOES-East) Visible (0.63 µm) images (below) showed the eye of Patricia from sunrise on 23 October until landfall along the west coast of Mexico around 2315 UTC. A mesonet station at the Chamela-Cuixmala Biosphere Reserve (located approximately 10 miles northwest of the eye landfall position) reported maximum sustained winds of 185 mph at 2350 UTC, with a peak wind gust of 210.9 mph at 2310 UTC.

MIMIC morphed microwave imagery (below) showed the development and motion of the very compact eye during the 22-23 October period. There was also a signature of the formation of a secondary outer eyewall, suggesting that an eyewall replacement cycle was underway as Patricia was approaching the west coast of Mexico.

View a 23 October weather briefing held at CIMSS to discuss Hurricane Patricia here.

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

Following the landfall of Patricia late in the day on 23 October, and increase in offshore sediment could be seen in Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images (from the RealEarth web map server) on 24 and 25 October (below), a result of runoff from heavy rains inland.

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Himawari-8 viewed Typhoon Champi in the North Pacific on 22 October 2015, as shown above. The storm was near peak intensity during this animation, as indicated by the graphs of satellite maximum wind speed and minimum surface pressure shown below (taken from this website). The eye (abnormally large for a Typhoon!) of Champi passed just to the south of the island of Iwo Jima, where a wind gust of 72 knots (83 mph) occurred at 09 UTC (surface observations). The Himawari-8 AHI instrument has 16 channels, as will the GOES-R ABI when it is launched in October 2016.

The Himawari-8 AHI instrument is also capable of gathering rapid-scan images over specified “Target Areas” every 2.5 minutes; rapid-scan Visible (0.64 µm) images of the eye of Typhoon Champi are shown below (also available as an MP4 animation). The GOES-R ABI will have the capability to scan special mesoscale sectors at 1-minute or even 30-second intervals.

Himawari-8 data — all channels — are routinely available here and here.

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A plot of the Advanced Dvorak Technique (ADT) intensity estimate for Hurricane Olaf (above) showed that the storm went through a period of rapid intensification during the 19-20 October 2015 period, reaching Category 4 strength. The National Hurricane Center noted that Olaf became the 6th major hurricane in the eastern North Pacific during the 2015 season, and that this was is the farthest south (9.9º N latitude) that a major hurricane had formed in that ocean basin since reliable records began in 1971 (discussion archive: NHC | CPHC).

4-km resolution GOES-15 (GOES-West) 10.7 µm Infrared channel images during the period of rapid intensification (below) revealed that cloud-top IR brightness temperatures were quite cold (in the -80º to -90º C range, violet colors) early in the day on 19 October, but then warmed a bit into the -70º to -80º C range (black to white shades) on 20 October as the eye became more well-defined.

A 375-meter resolution Suomi NPP VIIRS Infrared (11.45 µm) image at 10:23 UTC on 20 October (below) hinted at the presence of mesovortices within the eye of Hurricane Olaf.

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