Eruption of Mount Veniaminof on the Alaska Peninsula

November 21st, 2018 |
GOES-17

GOES-17 “Red” Visible (0.64 µm) and Split Window Difference (10.3-12.3 µm) images [click to play MP4 animation]

* GOES-17 images posted here are preliminary and non-operational *

Following an eruption of Mount Veniaminof on 21 November 2018, 1-minute Mesoscale Domain Sector GOES-17 “Red” Visible (0.64 µm) and Split Window Difference (10.3-12.3 µm) images (above) showed the volcanic ash plume drifting southeastward over the Gulf of Alaska. During the period 1947-2323 UTC the plume was seen to grow to a length of 200 miles from the volcano summit. Note in the Visible imagery that the 2625 ft (800 m) volcano acted as a barrier to the northwesterly boundary layer winds to create a cloud-free “notch” immediately downwind of Veniaminof.

NOAA-20 VIIRS True Color RGB images viewed using RealEarth (below) highlighted the light brown color of the ash plume.

NOAA-20 VIIRS True Color RGB images [click to enlarge]

NOAA-20 VIIRS True Color RGB images [click to enlarge]

A sequence of retrieved Ash Probability, Ash Height and Ash Loading (source) derived from Terra/Aqua MODIS and Suomi NPP VIIRS data (below) indicated high probabilities of ash content, height values primarily in the 4-6 km range and ash loading exceeding 4 g/m3 at times.

Terra/Aqua MODIS and Suomi NPP VIIRS Ash Probability, Ash Height and Ash Loading images [click to play animation | MP4]

Terra/Aqua MODIS and Suomi NPP VIIRS Ash Probability, Ash Height and Ash Loading images [click to play animation | MP4]

 

Increasing ice concentration in Hudson Bay

November 21st, 2018 |

Sea ice concentration derived from AMSR2 data, 06-21 November [click to play animation | MP4]

Daily sea ice concentration derived from AMSR2 data, 06-21 November [click to play animation | MP4]

After increasingly colder air began moving from eastern Nunavut across Hudson Bay beginning on 06 November (surface analyses), the daily sea ice concentration as derived from GCOM-W1 AMSR2 data (source) began to increase in the northern half of Hudson Bay (above) — especially after 15 November once mid-day (18 UTC) temperatures colder than -20ºF were seen at reporting stations along the northwest coast.

A sequence of daily Terra/Aqua MODIS True Color Red-Green-Blue (RGB) images (source) showed signatures of the increasing of ice coverage.

Terra/Aqua MODIS True Color RGB images, 06-21 November [click to play animation | MP4]

Daily Terra/Aqua MODIS True Color RGB images, 06-21 November [click to play animation | MP4]

A toggle between Terra MODIS True Color and False Color RGB images on 21 November (below) confirmed that much of the northern half of Hudson Bay contained ice — snow/ice (as well as ice crystal clouds) appear as darker shades of red in the False Color image (in contrast to the cyan shades of supercooled water droplet clouds).

Terra MODIS True Color and False Color RGB images on 21 November [click to enlarge]

Terra MODIS True Color and False Color RGB images on 21 November [click to enlarge]

19 November maps of Ice Concentration, Ice Stage and Departure from Normal via the Canadian Ice Service (below) further characterized this ice formation, which was ahead of normal for the central portion of Hudson Bay.

Ice Concentration [click to enlarge]

Ice Concentration [click to enlarge]

Ice Stage [click to enlarge]

Ice Stage [click to enlarge]

Ice Concentration Departure [click to enlarge]

Ice Concentration Departure [click to enlarge]

Mesoscale Convective System in Argentina

November 13th, 2018 |

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images, with GLM Groups plotted in cyan/green [click to play MP4 animation]

In support of the RELAMPAGO-CACTI field experiment, GOES-16 (GOES-East) had a Mesoscale Domain Sector centered over northeastern Argentina on 13 November 2018 — and 1-minute “Clean” Infrared Window (10.3 µm) images with plots of GLM Groups (above) showed a large and long-lived Mesoscale Convective System moving eastward across far northeastern Argentina and expanding into southern Paraguay and southeastern Brazil. Note the large amount of lightning in the anvil region far southeast of the core of the convection.

The corresponding GOES-16 Infrared animation without lightning data is shown below. Minimum cloud-top infrared brightness temperatures often reached -90ºC and colder (yellow pixels embedded within darker violet regions).

GOES-16 "Clean" Infrared Window (10.3 µm) images [click to play MP4 animation]

GOES-16 “Clean” Infrared Window (10.3 µm) images [click to play MP4 animation]

A comparison of NOAA-20 VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images using RealEarth (below) provided a very detailed view of the MCS at 1703 UTC. On the Infrared image, storm-top signatures often associated with severe thunderstorms included a well-defined enhanced-V (with a pronounced cold/warm couplet) situated over the Paraguay/Argentina border, and a “warm trench” surrounding the cold overshooting top at the vertex of the enhanced-V over extreme southern Paraguay.

NOAA-20 VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images at 1703 UTC [click to enlarge]

NOAA-20 VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images at 1703 UTC [click to enlarge]

The warm trench signature was also evident on 2-km resolution GOES-16 Infrared imagery at that same time (below), just west of Posadas, Argentina SARP. However, the warm trench surrounding the small overshooting top was only apparent from 1700 to 1705 UTC — so it was remarkable timing to have an overpass of the NOAA-20 satellite capture the brief signature in greater detail (at 375-meter resolution). A similar short-lived small overshooting top was seen at the vertex of the enhanced-V signature for the 6-minute period centered at 1652 UTC.

GOES-16 "Clean" Infrared Window (10.3 µm) image at 1703 UTC, with and without GLM Groups plotted in cyan/green [click to enlarge]

GOES-16 “Clean” Infrared Window (10.3 µm) image at 1703 UTC, with and without GLM Groups plotted in cyan/green [click to enlarge]

Woolsey Fire in southern California

November 9th, 2018 |

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

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

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above) showed the thick smoke and hot thermal signature of the Woolsey Fire in southern California on 09 November 2018. On this day it exhibited extreme fire behavior, with the large thermal anomaly or fire “hot spot” (red enhancement) moving rapidly southwestward and reaching the coast (Wildfire Today). The fires were driven by hot, dry Santa Ana winds, which arrived at Camarillo KCMA around 19 UTC (11 AM local time) and reached the coast at Point Mugu Naval Air Station KNTD around 22 UTC (2 PM local time).

A longer animation of GOES-16 Shortwave Infrared imagery (below) begins at 2115 UTC (1:15 PM local time) on 08 November — when a Mesoscale Sector was first positioned over California — and ends 52.5 hours later at 0149 UTC on 11 November (5:49 PM local time on 10 November). The first Ventura County fire to show a pronounced thermal signature was the Hill Fire; the earliest appearance of Woolsey Fire pixels that were hot enough to be color-enhanced (yellow) was at 2254 UTC (30 minutes after the reported start time of 2224 UTC). The area of hottest (red) pixels then began to increase in coverage and spread toward the southwest after about 06 UTC on 09 November (10 PM local time on 08 November), when Santa Ana winds began to increase at higher elevations several miles inland. As was seen in the Visible / Shortwave Infrared animation above, the morning period from 15-19 UTC (7-11 AM local time) on 09 November was when the fire moved very quickly toward the California coast and the beaches of Malibu. After sunset on 09 November, the area and intensity of hot red/yellow pixels began to decrease, and after 10 UTC (2 AM local time) on 10 November only darker black fire pixels persisted. During the day on 10 November, color-enhanced hot fire pixels were again evident from 1726-2353 UTC (9:26 AM to 3:53 PM local time). Note that at 19 UTC the marine layer began to move inland, with the dewpoint jumping to 46ºF at KNTO and to 33ºF at KCMA an hour later — the fire responded to this influx of moist air by beginning to die down.

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]

A nighttime comparison of Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images at 0923 UTC (1:23 AM local time) on 10 November (below) showed a marked reduction in coverage and intensity of hot pixels compared to 15 hours earlier.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images at 0923 UTC [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images at 0923 UTC [click to enlarge]

The smoke was very dense as it moved out over the adjacent offshore waters of the Pacific Ocean on 09 November, as seen in a sequence of MODIS and VIIRS Visible images (below).

MODIS and VIIRS Visible images [click to enlarge]

MODIS and VIIRS Visible images [click to enlarge]

VIIRS True Color Red-Green-Blue (RGB) images from Suomi NPP at 2104 UTC and NOAA-20 at 2154 UTC on 09 November (below) also depicted the optically-thick nature of the smoke.

Suomi NPP VIIRS True Color image at 2104 UTC [click to enlarge]

Suomi NPP VIIRS True Color RGB image at 2104 UTC [click to enlarge]

NOAA-20 VIIRS True Color image at 2154 UTC [click to enlarge]

NOAA-20 VIIRS True Color RGB image at 2154 UTC [click to enlarge]

The smoke was so thick that Suomi NPP VIIRS Aerosol Optical Depth values exceeded 1.0 (below) —  this is likely due to the VIIRS Cloud Mask product (a component of the AOD algorithm)  falsely flagging the thick center portion of the smoke as “cloud”.

Suomi NPP VIIRS True Color RGB and Aerosol Optical Depth [click to enlarge]

Suomi NPP VIIRS True Color RGB and Aerosol Optical Depth [click to enlarge]

===== 11 November Update =====

GOES-16

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

Santa Ana winds began to increase again on 11 November — 1-minute GOES-16 Visible and Shortwave Infrared images (above) showed the development of new smoke plumes and hot thermal signatures around the periphery of the ongoing Woolsey Fire. As of 1812 UTC (10:12 AM local time), the fire had burned 83,275 acres and was listed as 10% contained.

The new smoke plumes (as well as residual smoke from previous days of burning) could be seen on VIIRS True Color RGB imagery from Suomi NPP at 2029 UTC and NOAA-20 at 2114 UTC (below). The entire image swaths as captured and processed by the Direct Broadcast ground station at CIMSS/SSEC can be seen here and here.

Suomi NPP VIIRS True Color RGB image at 2029 UTC [click to enlarge]

Suomi NPP VIIRS True Color RGB image at 2029 UTC [click to enlarge]

NOAA-20 VIIRS True Color RGB image at 2114 UTC [click to enlarge]

NOAA-20 VIIRS True Color RGB image at 2114 UTC [click to enlarge]