Thermal signature of missile strikes at Shayrat Air Base in Syria

April 7th, 2017 |

EUMETSAT Meteosat-10 Shortwave Infrared (3.9 µm) images, with hourly surface reports; Shayrat Air Base is located at the center of the cyan circle [click to play animation]

EUMETSAT Meteosat-10 Shortwave Infrared (3.9 µm) images, with hourly surface reports; Shayrat Air Base is located at the center of the cyan circle [click to play animation]

EUMETSAT Meteosat-10 Shortwave Infrared (3.9 µm) images (above) showed the thermal signature or “hot spot” (darker black pixels) of fires resulting from US missile strikes at Syria’s Shayrat Air Base on 07 April 2017. The warmest infrared brightness temperature was 300.22 K on the 0030 UTC image (the SEVIRI instrument was scanning the Shayrat region at 00:40 UTC), which was about 25 K warmer than the surrounding background temperatures; though the fires were much smaller than the nominal 3 km spatial resolution of the 3.9 µm detector, the sub-pixel effect enables a signal of the fire radiative power to be registered.

A toggle between the 0015 and 0030 UTC images displayed using McIDAS-V (below; courtesy of William Straka, SSEC) highlights the appearance of the thermal signature at Shayrat Air Base. Two persistent hot spots located northeast of Palmyra could have been due to refinery or mining activities.

EUMETSAT Meteosat-10 Shortwave Infrared (3.9 µm) images at 0015 and 0030 UTC [click to enlarge]

EUMETSAT Meteosat-10 Shortwave Infrared (3.9 µm) images at 0015 and 0030 UTC [click to enlarge]

GOES-16 visible and thermal signatures of Space-X EchoStar 23 rocket launch

March 16th, 2017 |

GOES-16 Visible (0.64 µm, left), Near-Infrared (1.61 µm, center) and Shortwave Infrared (3.9 µm, right) images [click to enlarge]

GOES-16 Visible (0.64 µm, left), Near-Infrared (1.61 µm, center) and Shortwave Infrared (3.9 µm, right) images [click to enlarge]

** The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. **

Visible and thermal signatures of the Space-X EchoStar 23 rocket launch were seen with GOES-16 imagery on 16 March 2017. The set of 3 images above consists of 5-minute CONUS sector scans at 05:54:33 UTC (about 5 minutes before launch), 05:59:33 UTC (around launch time) and 06:04:33 UTC (about 5 minutes after launch). The 05:59:33 UTC image was actually scanning the NASA Kennedy Space Center (station identifier KXMR)  area at 06:00:38 UTC, just after the 06:00 UTC launch time. A faint bright glow of the rocket booster was seen on the 0.5-km resolution Visible (0.64 µm) image; the 1-km resolution Near-Infrared (1.61 µm) rocket signature was much brighter, because this spectral band senses radiation from both visible and infrared portions of the electromagnetic radiation spectrum (which of the two was a stronger contributor to the bright signal is difficult to determine); the 2-km resolution Shortwave Infrared (3.9 µm) image displayed a warm (dark black enhancement) “hot spot”, although it was not exceptionally warm (with a 306.8 K maximum brightness temperature).

A “warm signal” was also observed on the three GOES-16 ABI Water Vapor bands: Lower-Level (7.3 µm), Mid-Level (6.9 µm) and Upper-Level (6.2 µm), as shown below. While water vapor is certainly a by-product of rocket booster combustion, it is important to remember that the Water Vapor bands are first and foremost Infrared bands that sense the brightness temperature of a layer of moisture (which can vary in both altitude and depth, depending on the temperature/moisture profile of the atmosphere and/or the satellite viewing angle). In this case, the atmosphere was relatively dry over the region, with little moisture aloft to attenuate the rocket signature — shifting the roughly-corresponding GOES-13 Sounder (had the GOES-13 Sounder instrument been operational)  water vapor weighting functions (available from this site) to lower altitudes. However, moisture considerations aside, the rocket signature seen on the 05:59:33 UTC water vapor imagery was primarily a thermal anomaly.

GOES-16 Lower-Level Water Vapor (7.3 µm, left), Mid-Level Water Vapor (6.9 µm, middle) and Upper-Level Water Vapor (6.2 µm, right) images [click to enlarge]

GOES-16 Lower-Level Water Vapor (7.3 µm, left), Mid-Level Water Vapor (6.9 µm, middle) and Upper-Level Water Vapor (6.2 µm, right) images [click to enlarge]

McIDAS-V images of GOES-16 Near-Infrared (1.6 µm and 2.2 µm) and Shortwave Infrared (3.9 µm) data at 05:59:33 UTC (below; courtesy of William Straka, SSEC) provided another view of the rocket launch signature.

GOES-16 Near-Infrared (1.61 µm and 2.2 µm) and Shortwave Infrared (3.9 µm) images [click to enlarge]

GOES-16 Near-Infrared (1.61 µm and 2.2 µm) and Shortwave Infrared (3.9 µm) images [click to enlarge]

Turbulence over the central Pacific Ocean

December 27th, 2016 |
Himawari-8 Water Vapor Imagery (6.2 µm, top; 6.9 µm, middle; 7.3 µm, bottom), 1700-1900 UTC on 27 December 2016 [click to enlarge]

Himawari-8 Water Vapor Imagery (6.2 µm, top; 6.9 µm, middle; 7.3 µm, bottom), 1700-1900 UTC on 27 December 2016 [click to enlarge]

Turbulence over the Pacific Ocean affected at least one flight on Tuesday 27 December 2016 near 24º N, 162º E, as indicated by a pilot report issued at 1745 UTC:

PGUA UUA /OV 24N 162E/TM 1745/FL340/TP B777/TB MOD-SEV/RM ZOA

In the animation above of the three Himawari-8 Water Vapor bands (sensing radiation emitted at 6.2 µm, 6.9 µm and 7.3 µm), a characteristic banded gravity wave structure is evident which is associated with the pilot report of moderate to severe turbulence (Note: the ABI instrument on the GOES-R series of satellites will feature these same 3 upper level, mid-level and lower level water vapor bands). In contrast to a turbulence event earlier this month, documented here on this blog, the wave features responsible for this turbulence were more distinct in 8-bit McIDAS-X imagery, and were also apparent in all three water vapor bands.

The Himawari-8 satellite data were used in the subsequent issuance of a SIGMET (Significant Meteorological Information) advisory:

WSPA06 PHFO 271824
SIGPAS

KZAK SIGMET SIERRA 1 VALID 271825/272225 PHFO-
OAKLAND OCEANIC FIR MOD OCNL SEV TURB FCST BTN FL280 AND FL360.
WI N2640 E16810 – N2120 E16810 – N2120 E16240 – N2640 E16250
– N2640 E16810. MOV E 25KT. BASED ON ACFT AND SAT.

The full 11-bit McIDAS-V imagery from the 6.2 µm Water Vapor band on Himawari-8, below, shows multiple ephemeral signatures of potential turbulence. In contrast to the event on 14 December, the gravity waves in this event perturbed clouds enough that they were also apparent in the Infrared Window band, as shown in this toggle between the 10.4 µm and 6.2 µm images. Himawari-8 Infrared Window brightness temperatures exhibited by the gravity wave were in the -30º to -40ºC range at 1740 UTC, which roughly corresponded to altitudes of 30,000-34,000 feet according to data from the 12 UTC rawinsonde report from Minamitorishima RJAM (IR image | text) located about 890 km or 550 miles to the west of the wave feature. Additional Himawari-8 Water Vapor images created using AWIPS II are here for the 6.2 µm imagery (from 1720-1740 UTC); this is a toggle between 6.2 µm and 7.3 µm imagery at 1720 UTC.

Himawari-8 Infrared Imagery (6.2 µm), 1600-1900 UTC on 27 December 2016 [click to animate]

Himawari-8 Water Vapor (6.2 µm) Imagery, 1600-1900 UTC on 27 December 2016 [click to animate]

The superior spatial resolution of Himawari-8 (2-km at the sub-satellite point) was vital in detecting the gravity wave features causing the turbulence. Water Vapor imagery from COMS-1, with a nominal resolution of 4 km, does not show the features associated with the turbulence report.

COMS-1 Infrared Imagery (6.75 µm), 1630-1800 UTC on 27 December 2016 [click to animate]

COMS-1 Water Vapor (6.75 µm) Imagery, 1630-1800 UTC on 27 December 2016 [click to animate]

Similarly, HimawariCast data that is broadcast at reduced resolution was insufficient to monitor this event. See the toggle below from 1740 UTC.

Himawari-8 Infrared Imagery (6.2 µm) at 1740 UTC on 27 December 2016, native resolution and as distributed via Himawaricast [click to enlarge]

Himawari-8 Water Vapor (6.2 µm) Imagery at 1740 UTC on 27 December 2016, at native resolution and as distributed via Himawaricast [click to enlarge]

Moderate to severe turbulence aloft near the International Date Line

December 14th, 2016 |

Himawari-8 Water Vapor (6.2 µm) images, with pilot reports of turbulence [click to play animation]

Himawari-8 Water Vapor (6.2 µm) images, with pilot reports of turbulence [click to play animation]

Himawari-8 Water Vapor (6.2 µm) images (above; also available as MP4 and McIDAS-V animations) revealed the presence of a subtle packet of upper-tropospheric gravity waves propagating southeastward near the International Date Line (180º longitude over the central Pacific Ocean), just to the west/southwest of Midway Atoll on 14 December 2016 — and there were a few pilot reports of moderate to severe turbulence (which were responsible for at least one injury) in the general vicinity of this gravity wave feature from 1530 to 1740 UTC, at altitudes of 35,000 to 38,000 feet:

PHNL UUA /OV 2800N 18000W/TM 1530/FL380/TP B767/TB MOD-SEV/RM ZOA CWSU
PHNL UUA /OV 2643N 17757W/TM 1732/FL350/TP A330/TB SEV/RM ZOA CWSU
PHNL UUA /OV 2626N 17917W/TM 1740/FL360/TP B747/TB SEV/RM ZOA CWSU

A larger-scale view using all 3 water vapor bands of the AHI instrument on the Himawari-8/9 satellites (below; also available as an MP4 animation) showed that a broad trough was moving eastward away from the International Date Line, with the signature of a jet streak diving southward toward the region of the turbulence reports (Note: the ABI instrument on the GOES-R series of satellites will feature these same 3 upper level, mid-level and lower level water vapor bands).

Himawari-8 Water Vapor (6.2 µm, top; 6.9 µm, middle; 7.4 µm, bottom) images [click to play animation]

Himawari-8 Water Vapor (6.2 µm, top; 6.9 µm, middle; 7.4 µm, bottom) images [click to play animation]

GFS model 250 hPa analyses (12 UTC | 18 UTC | source) confirmed that the region of turbulence reports was located within the exit region an approaching 50-70 m/s or 97-136 knot upper tropospheric jet, where convergence (red contours) was maximized.


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Similarly, Himawari-8 water vapor image Derived Motion Winds, below, also indicated increasing upper-tropospheric convergence along the International Date Line (180º longitude) between 25º and 30º N latitude from 12 UTC to 18 UTC (below; source).

Himawari-8 water vapor image Derived Motion Winds at 12 UTC, with corresponding contours of Upper-tropospheric divvergence [click to enlarge]

Himawari-8 water vapor image Derived Motion Winds at 12 UTC, with corresponding contours of Upper-tropospheric divvergence [click to enlarge]

Himawari-8 water vapor image Derived Motion Winds at 15 UTC, with corresponding contours of Upper-tropospheric divergence [click to enlarge]

Himawari-8 water vapor image Derived Motion Winds at 15 UTC, with corresponding contours of Upper-tropospheric divergence [click to enlarge]

Himawari-8 water vapor image Derived Motion Winds at 18 UTC, with corresponding contours of Upper-tropospheric divergence [click to enlarge]

Himawari-8 water vapor image Derived Motion Winds at 18 UTC, with corresponding contours of Upper-tropospheric divergence [click to enlarge]

A comparison of 2-km resolution Himawari-8 and 4-km resolution GOES-15 Water Vapor images (below; also available as an MP4 animation) showed that the gravity wave feature was not readily apparent on the lower spatial resolution GOES-15 images (which were only available every 30 minutes, in contrast to every 10 minutes from Himawari-8). The same color enhancement is applied to both sets of images — but because of differences between the Himawari-8 vs GOES-15 water vapor band characteristics (namely the central wavelength and the spectral response function, but also the water vapor weighting function profiles as influenced by the dissimilar satellite viewing angles) the resulting water vapor images differ in their general appearance.

Himawari-8 Water Vapor (6.2 µm, left) and GOES-15 Water Vapor (6.5 µm, right) images, with pilot reports of turbulence [click to play animation]

Himawari-8 Water Vapor (6.2 µm, left) and GOES-15 Water Vapor (6.5 µm, right) images, with pilot reports of turbulence [click to play animation]

This case demonstrated well the importance of viewing all 11 bits of information contained in the Himawari-8 Imagery. The animation at the top of the Blog Post shows an 8-bit display; a similar 8-bit display that uses a different color enhancement is here, courtesy of Dan Lindsey at CIRA. All 8-bit displays are limited to 256 different colors. The image below compares 8-bit (McIDAS-X on the left) and 11-bit (McIDAS-V on the right) displays at 1530 UTC.

Himawari-8 Water Vapor (6.2 µm) image at 1530 UTC, as viewed using 8-bit McIDAS-X (left) and 11-bit McIDAS-V (right) displays [click to enlarge]

Himawari-8 Water Vapor (6.2 µm) image at 1530 UTC, as viewed using 8-bit McIDAS-X (left) and 11-bit McIDAS-V (right) displays [click to enlarge]

Here is a toggle from AWIPS that compares 11-bit and 8-bit displays. The feature causing the turbulence is quite subtle, and 11-bit displays (which allow 2048 different colors) are necessary to accurately show it.