Swan Lake Fire in Alaska

August 17th, 2019 |

GOES-17

GOES-17 “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-17 “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above) revealed thick smoke and a pronounced thermal anomaly associated with the Swan Lake Fire which was burning on the Kenai Peninsula in south-central Alaska on 17 August 2019. Later in the day, a few pyrocumulus jumps could be seen in Visible imagery over the fire source region.

Strong northwesterly winds were transporting smoke from the Swan Lake Fire across the Kenai Peninsula and the Seward area — a time series of surface report data from Seward (below) showed that this smoke reduced the visibility to 1-2 miles at times.

Time series of surface reports from Seward, Alaska [click to enlarge]

Time series of surface report data from Seward, Alaska [click to enlarge]

The Air Quality Index reached 410 at Copper Landing and 358 at Seward (below).

Air Quality Index at Copper Landing and Seward [click to enlarge]

Air Quality Index at Copper Landing and Seward [click to enlarge]

The southward transport of smoke across the Seward area and out across the adjacent offshore waters of the Gulf of Alaska was evident in VIIRS True Color Red-Green-Blue (RGB) images from NOAA-20 and Suomi NPP, as viewed using RealEarth (below).

VIIRS True Color RGB images from NOAA-20 and Suomi NPP [click to enlarge]

VIIRS True Color RGB images from NOAA-20 and Suomi NPP [click to enlarge]

GOES-17 ABI Temperature Data Quality Flags (TDQF) thresholds update

August 8th, 2019 |

Top: Thumbnails of GOES-17 and GOES-16 ABI Band 12 (9.6 µm) on August 1, 2019. Bottom: Time series of GOES-17 minus GOES-16 brightness temperature for a region located between the two satellites. Also plotted is the GOES-17 Focal Plane Temperature. The reduced duration of the GOES-17 data to be flagged is highlighted. [click to enlarge]

As of 19:45 UTC on August 8, 2019, the new Look-Up-Table (LUT) went into operations for use in the GOES-17 ABI Temperature Data Quality Flags (TDQF). These hotter thresholds are possible due to the recent implementation of the Predictive Calibration algorithm.  Note that the image also includes the percent good (and conditionally usable) values (flagged 0 or 1) for both GOES-16 and GOES-17 ABI. Recall there are 5 Data Quality Flags for ABI data:

  • DQF:percent_good_pixel_qf = 1.f ;
  • DQF:percent_conditionally_usable_pixel_qf = 0.f ;
  • DQF:percent_out_of_range_pixel_qf = 0.f ;
  • DQF:percent_no_value_pixel_qf = 0.f ;
  • DQF:percent_focal_plane_temperature_threshold_exceeded_qf = 0.f

The last one, DQF:percent_focal_plane_temperature_threshold_exceeded_qf, reports what percentage of the images pixels are warmer than the threshold value. Note that the thresholds on both the increasing and decreasing temperatures are also reported in the meta-data.

Near realtime brightness temperature comparisons between GOES-16 and GOES-17, as well as historical comparisons for a region centered on the equator and half way between the two satellites.

From the NOAA Notification:

Product(s) or Data Impacted: GOES-17 ABI auxiliary field change

Date/Time of Initial Impact: August 8, 2019 1945 UTC

Details/Specifics of Change:

The GOES-17 ABI Temperature Data Quality Flags (TDQF) thresholds for the thermal bands have been updated to the values in the table below.  This update will make utilizing the TDQF more effective for flagging saturated data caused by the GOES-17 ABI cooling system anomaly. There will be no impacts to distribution caused by this update.

Table of updated Temperature Quality Data Flag thresholds [click to enlarge]

Table of updated Temperature Quality Data Flag thresholds [click to enlarge]

Tropical Depression Flossie near Hawai’i

August 5th, 2019 |

GOES-17

GOES-17 “Red” Visible (0.64 µm), “Clean” Infrared Window (10.35 µm) and Upper-level Water Vapor (6.2 µm) images [click to play animation | MP4]

An animation that cycles through GOES-17 (GOES-West) “Red” Visible (0.64 µm), “Clean” Infrared Window (10.35 µm) and Upper-level Water Vapor (6.2 µm) images (above) showed Tropical Depression Flossie just northeast of Hawai’i on 05 August 2019. Note that (1) the exposed low-level circulation center (LLCC) was very apparent in the visible imagery, (2) deep convection offset to the east/northeast of the LLCC exhibited cloud-top infrared brightness temperatures as cold as -83ºC , and (3) a series of gravity waves were propagating westward away from the convection, moving toward Hawai’i.

GOES-15 Infrared imagery and deep-layer wind shear data from the CIMSS Tropical Cyclones site (below) showed that the tropical cyclone was in an environment of strong shear, which was responsible for the displacement between the exposed LLCC and the convection. In addition to the wind shear, the weakening trend of the system was also due to its motion over cold Sea Surface Temperatures and low Ocean Heat Content.

GOES-15 Infrared Window (10.7 µm) images, with contours and streamlines of deep-layer wind shear [click to enlarge]

GOES-15 Infrared Window (10.7 µm) images, with contours and streamlines of deep-layer wind shear at 18 UTC [click to enlarge]

Severe thunderstorms in the Dakotas, as viewed by 4 GOES

August 3rd, 2019 |

 

Visible images from GOES-17, GOES-15, GOES-14 and GOES-16, with SPC Storm Reports plotted in red [click to play animation | MP4]

Visible images from GOES-17, GOES-15, GOES-14 and GOES-16, with SPC Storm Reports plotted in red [click to play animation | MP4]

With GOES-14 undergoing its annual INR testing and evaluation, it afforded the ability to monitor features such as severe thunderstorms in the western Dakotas from 4 GOES — GOES-17 (GOES-West) at 137.2ºW, GOES-15 at 128ºW, GOES-14 at 105ºW and GOES-16 (GOES-East) at 75.2ºW longitude (above). These storms produced hail as large as 2.0 inches in diameter and damaging winds to 75 mph (SPC Storm Reports). The images are displayed in the native projection of each satellite.