Cape Newenham, Alaska bow shock waves

June 10th, 2018 |

GOES-15 Visible (0.63 µm) images, with hourly plots of wind barbs [click to play animation]

GOES-15 Visible (0.63 µm) images, with hourly plots of wind barbs [click to play animation]

GOES-15 (GOES-West) Visible (0.63 µm) images (above) showed patches of fog and low stratus moving southwestward off Southwest Alaska and across the adjacent offshore waters of the Bering Sea on 10 June 2018.

A closer look using 250-meter resolution Terra/Aqua MODIS and 375-meter resolution Suomi NPP VIIRS true-color Red-Green-Blue (RGB) images from RealEarth (below) revealed a packet of “bow shock waves” created as the shallow fog/stratus interacted with the relatively rugged terrain of the narrow Cape Newenham land feature (Google Maps). Other examples of similar bow shock wave cloud features have been documented here, here and here.

Terra MODIS, Aqua MODIS and Suomi NPP VIIRS true-color RGB images [click to enlarge]

Terra MODIS, Aqua MODIS and Suomi NPP VIIRS true-color RGB images [click to enlarge]

A 30-meter resolution Landsat-8 false-color RGB image (below) provided a more detailed view of the bow shock wave structure. Snow cover (cyan) could be seen on some of the higher-elevation land features.

Landsat-8 false-color RGB image [click to enlarge]

Landsat-8 false-color RGB image [click to enlarge]

A time series plot of Cape Newenham surface observations (below) showed the fluctuations in visibility as northerly winds brought patches of fog over the site.

Time series plot of Cape Newenham surface observations [click to enlarge]

Time series plot of Cape Newenham surface observations [click to enlarge]

Eruption of the Fuego volcano in Guatemala

June 3rd, 2018 |

GOES-16 Visible (0.64 µm, left) and Infrared (10.3 µm, right) images, with hourly plots of surface reports {click to play animation]

GOES-16 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.3 µm, right) images, with hourly plots of surface reports [click to play MP4 animation]

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed that an explosive eruption of the Fuego volcano in Guatemala occurred just after 18 UTC on 03 June 2018. The height of the ash was estimated to be 50,000 feet.

The tan to light brown color of the ash cloud was evident on GOES-16 true-color Red-Green-Blue (RGB) images, as viewed using RealEarth (below).

GOES-16 true-color RGB images [click to play animation]

GOES-16 true-color RGB images [click to play animation]

On GOES-16 Shortwave Infrared (3.9 µm) imagery (below), note the appearance of a persistent thermal anomaly or “hot spot” at the summit of Fuego for about 5 hours prior to the explosive eruption. This thermal anomaly became apparent around 1300 UTC, after which time a low-level volcanic plume could be seen drifting northward.

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and Shortwave Infrared (3.9 µm, right) images, with hourly plots of surface observations [click to play MP4 animation]

GOES-16 Shortwave Infrared (3.9 µm) images [click to play MP4 animation]

GOES-16 Shortwave Infrared (3.9 µm) images [click to play MP4 animation]

16-panel composite of all ABI bands [click to play MP4 animation]

16-panel composite of all ABI bands [click to play MP4 animation]

 

Minor explosive eruption of Kilauea in Hawai’i

May 19th, 2018 |

Himawari-8 Ash Cloud Height product {click to play animation]

Himawari-8 Ash Cloud Height product [click to play animation]

An explosive eruption from the Halema’uma’u crater at the Kilauea summit on the Big Island of Hawai’i occurred around 1550 UTC on 19 May 2018. Using Himawari-8 data, multispectral retrievals of parameters such as Ash Cloud Height (above) and Ash Loading (below) from the NOAA/CIMSS Volcanic Cloud Monitoring site helped to characterize the volcanic ash plume.

Himawari-8 Ash Loading product [click to play animation]

Himawari-8 Ash Loading product [click to play animation]

Later in the day, a Suomi NPP VIIRS True-color Red-Green-Blue (RGB) image viewed using RealEarth (below) showed the hazy signature of volcanic smog or “vog” which had spread out to the south, southwest and west of the Big Island. Light amounts of ash fall were reported downwind of Kilauea.

Suomi NPP VIIRS True-color RGB image [click to enlarge]

Suomi NPP VIIRS True-color RGB image [click to enlarge]

PyroCumulonimbus cloud in Texas

May 11th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, center) and “Clean” Infrared Window (10.3 µm, bottom) images, with hourly plots of surface reports [click to play MP4 animation]

A large pyroCumulonimbus (pyroCb) cloud developed from the Mallard Fire in the Texas Panhandle on 11 May 2018, aided by warm temperatures and strong winds ahead of an approaching dryline (surface analyses).  1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed the large thermal anomaly or “hot spot” (red 3.9 µm pixels) and the rapid development of  the pyroCb cloud beginning shortly after 1900 UTC. Cloud-top infrared brightness temperatures cooled to -60 ºC — the tropopause temperature on the 00 UTC Amarillo sounding — by around 2130 UTC. On the Shortwave Infrared imagery, note the relatively warm (darker gray) appearance of the pyroCb cloud top — a characteristic signature of pyroCb anvils due to enhanced reflection of solar radiation off of smaller cloud-top particles.

4-panel comparisons of Suomi NPP VIIRS Visible (0.64 µm), Near-Infrared “Snow/Ice” (1.61 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images at 1936 UTC and 2029 UTC (below) revealed that the maximum differences between 3.74 µm and 11.45 µm cloud-top infrared brightness temperatures — at the same location on the pyroCb anvil — were 86ºC (+26ºC and -59ºC at 1936 UTC) and 91.5ºC (+27.5ºC and -63ºC at 2029 UTC).

Suomi NPP VIIRS Visible (0.64 µm), Near-Infrared

Suomi NPP VIIRS Visible (0.64 µm, upper left), Near-Infrared “Snow/Ice” (1.61 µm, upper right), Shortwave Infrared (3.74 µm, lower left) and Infrared Window (11.45 µm, lower right) images at 1936 UTC and 2029 UTC [click to enlarge]

Lightning was detected from portions of the smoke plume, as well as the core of the pyroCb thunderstorm.

After dark, the thermal signature of the Mallard Fire was also apparent on GOES-16 Near-Infrared “Cloud particle size” (2.24 µm) imagery (below).

GOES-16 Near-Infrared

GOES-16 Near-Infrared “Cloud particle size” (2.24 µm, top), Shortwave Infrared (3.9 µm, center) and “Clean” Infrared Window (10.3 µm, bottom) images, with hourly plots of surface reports [click to play MP4 animation]

===== 12 May Update =====

Terra MODIS True-color and False-color images [click to enlarge]

Terra MODIS True-color and False-color images [click to enlarge]

In a comparison of 250-meter resolution Terra MODIS True-color and False-color Red-Green-Blue (RGB) images from the MODIS Today site (above), the Mallard Fire burn scar was evident in the False-color. Both images showed a smoke plume from ongoing fire activity, which was drifting northward across the Texas Panhandle.

The corresponding Terra MODIS Land Surface Temperature product (below) indicated that LST values within the burn scar were as high as 137ºF (darker red enhancement), in contrast to values around 100ºF adjacent to the burn scar.

Terra MODIS Land Surface Temperature product [click to enlarge]

Terra MODIS Land Surface Temperature product [click to enlarge]