Actinoform cloud in the East Pacific

November 16th, 2021 |

GOES-17 True Color RGB images [click to play animated GIF | MP4]

GOES-17 (GOES-West) True Color RGB images created using Geo2Grid (above) showed a cyclonically-rotating actinoform cloud feature that was moving west-southwestward across the East Pacific Ocean (about midway between Hawai’i and California) on 16 November 2021.

In GOES-17 Day Cloud Phase Distinction RGB images (below), the increasing shades of green exhibited by the curved bands of shallow convection suggested that those features were likely mixed-phase clouds — composed of a combination of liquid/supercooled water droplets and ice particles. 

GOES-17 Day Cloud Phase Distinction RGB images [click to play animated GIF | MP4]

Similarly, in a toggle between NOAA-20 VIIRS True Color and False Color RGB images viewed using RealEarth (below), darker shades of cyan suggested the presence of mixed-phase banded cloud elements within the core of the actinoform feature.

NOAA-20 VIIRS True Color and False Color images at 2218 UTC [click to enlarge]

Other examples of actinoform clouds can be examined by scrolling through this link.

ACSPO SSTs on 9 November

November 9th, 2021 |
ACSPO SSTs over the northern Gulf of Mexico derived from NOAA-20 VIIRS data, 0800 UTC 09 Nov 2021 (Click to enlarge)

The Advanced Clear Sky Processor for Ocean algorithm is part of the Community Software Processing Package (CSPP), CIMSS-maintained software that can be applied to Direct Broadcast data, such as those data from NOAA-20 and Suomi-NPP (and other satellites) downloaded at two antennae at CIMSS. CSPP will create AWIPS-ready tiles so that SST information can be viewed within AWIPS (as shown above and below) and the AWIPS-ready tiles are available via LDM feed from CIMSS (images — rather large — are also routinely available online: here for the image above, here for the Suomi-NPP-derived image below).

Both SST images show remarkable gradients in sea surface temperature: upper 60s (cyan) to low 80s (yellow) just south of Louisiana in less than 20 miles (above); low 60s (blue) to 80 (chartreuse) to the east of the Outer Banks, also in less than 20 miles (below). The warmest water in the Gulf of Mexico is around 83º F, and shelf water is in the mid-60s. Warmest Gulf Stream waters are around 81º F. Magenta values correspond to temperatures in the 50s.

ACSPO SSTs over the northern Gulf of Mexico derived from Suomi-NPP VIIRS data, 0710 UTC 09 Nov 2021 (Click to enlarge)

Buck Fire in North Texas

October 28th, 2021 |

GOES-16 True Color RGB images [click to play animated GIF | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) True Color RGB images created using Geo2Grid (above) showed a distinct smoke plume associated with the Buck Fire in North Texas on 28 October 2021. The fire spread rapidly toward the southeast, driven by strong northwesterly winds gusting in excess of 40 knots. Note that the brighter white smoke plume was embedded within broader plumes of blowing dust (shades tan to light brown).

In a sequence of 1-minute GOES-16 “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images along with 5-minute Fire Temperature and Fire Power derived products — all with an overlay of 5-minute Visible Derived Motion Winds (below), the maximum surface 3.9 µm brightness temperature sensed with this fire was 138.7ºC (which is the saturation temperature for the ABI Band 7 detectors), the peak Fire Temperature exceeded 2900 K and the Fire Power reached 1800 MW (the Fire Temperature and Fire Power derived products are components of the GOES Fire Detection and Characterization Algorithm FDCA). Derived Motion Winds tracked the smoke plume moving southeastward at speeds up to 49 knots.

GOES-16 Visible, Shortwave Infrared, Fire Temperature, and Fire Power with an overlay of Derived Motion Winds [click to play animated GIF | MP4]

===== 29 October Update =====

NOAA-20 VIIRS DayNight Band image at 0816 UTC [click to enlarge]

During the subsequent nighttime hours, the bright glow of the Buck Fire could be seen on a NOAA-20 VIIRS Day/Night Band image at 0816 UTC or 3:16 am CDT, as viewed using RealEarth (above).

The fire continued to burn into the following day — and the burn scar could be seen in NOAA-20 VIIRS True Color and False Color images (below).

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

GOES-16 True Color RGB images (below) again displayed a long smoke plume that was transported southeastward. 

GOES-16 True Color RGB images [click to play animated GIF | MP4]

Alisal Fire in Southern California

October 12th, 2021 |

GOES-17 True Color RGB images [click to play animated GIF | MP4]

GOES-17 (GOES-West) True Color RGB images created using Geo2Grid (above) showed the transport of smoke from the Alisal Fire in Southern California on 12 October 2021. The dashed line in the images is Highway 101 — a portion of which was closed, as the wind-driven fire raced toward the coast. Late in the day some low-altitude smoke began to move eastward along the coast, eventually reducing the surface visibility to 6 miles at Santa Barbara.

During the preceding overnight hours (at 0916 UTC or 2:16 am PDT), a comparison of Suomi-NPP VIIRS Shortwave Infrared and Day/Night Band images (below) revealed the thermal signature and nighttime glow of the fire. The VIIRS imagery was downloaded and processed via the SSEC/CIMSS Direct Broadcast ground station.

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

The Suomi-NPP overpass time of the fire region was actually 0926 UTC — and a time-matched comparison of Shortwave Infrared images from GOES-17 and Suomi-NPP (below) demonstrated that the superior spatial resolution of VIIRS instrument (~375 meters, vs ~2 km for the ABI on GOES-17) provided a more accurate depiction of the areal coverage of the fire.

Shortwave Infrared images from Suomi-NPP (3.74 µm) and GOES-17 (3.9 µm) [click to enlarge]

===== 13 October Update =====

GOES-17 True Color RGB images [click to play animated GIF | MP4]

On 13 October, GOES-17 True Color RGB images (above) showed that as offshore wind speeds relaxed, a shift to onshore flow recirculated some of the smoke inland — with smoke briefly reducing the surface visibility to 1.5 miles at Santa Barbara airport (below). Farther to the south, residual smoke from the previous day of burning was also evident, with some of it traveling as far as Isla Guadalupe (Guadalupe Island) nearly 400 miles away.

Time series of surface observation data from Santa Barbara Municipal Airport [click to enlarge]