Increase in Gulf of Mexico water turbidity in the wake of Hurricane Irma

September 11th, 2017 |

Suomi NPP VIIRS true-color RGB images on 07 September and 11 September [click to enlarge]ep

A comparison of Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images on 07 September (before Irma) and 11 September (after Irma) revealed a marked increase in turbidity of the shallow Continental Shelf waters off the coast of southern/southwestern Florida and the Florida Keys. Irma moved through that region on 10 September as a Category 3 hurricane — and even though the center of Irma moved northward off/along the west coast of Florida (with a wind gust to 75 mph at Key West) , the strongest winds were recorded along/near the east coast of Florida: wind gusts to 92 mph and 109 mph and 142 mph — stirring up particulates within the shallow Continental Shelf waters.

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

Large-scale (CONUS) VIIRS true-color before-Irma and after-Irma images are available here and here. Note that the cloud shield of Irma had expanded as far westward as Kansas, Texas and Oklahoma on 12 September ( GOES-16 true-color images) — in addition to large areas of dense smoke from wildfires in the Pacific Northwest (blog post) which was drifting eastward across the northern US.

Category 5 Hurricane Irma over the Lesser Antilles

September 6th, 2017 |

Suomi NPP’s Day Night Band Image, below, from Real Earth, shows Hurricane Irma as it is over the island of Barbuda — note that the island is entirely within the eye! (Click here for an image with no underlying maps).

Suomi NPP Day Night Band Visible (0.7 µm) image, 0529 UTC on 6 September 2017, with underlying map (Click to enlarge)

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

GOES-16 Clean Window (10.3 µm) imagery at 30-second intervals, 0957 – 1202 UTC on 6 September 2017 (Click to animate)

GOES-16 Clean Window (10.3 µm) imagery, above, for two hours near sunrise on 6 September 2017 show a well-developed Irma moving through the islands to the east of Puerto Rico. The storm maintains its excellent satellite presentation with a distinct eye. Geostationary Lightning Mapper Data overlain on the 10.3 µm imagery (with a greyscale enhancement), below, shows that lightning continues to be active within the eyewall of this strong storm.

GOES-16 10.3 µm imagery at 15-minute intervals, with Geostationary Lightning Mapper (GLM) data overlain at 3-minute intervals, yellow oldest, red newest (Click to animate)

For the latest on this powerful storm, consult the National Hurricane Center website, or the CIMSS Tropical Weather Website.

Increase in Turbidity near the Texas Gulf Coast following Hurricane Harvey

August 30th, 2017 |

Terra MODIS True-Color imagery off the Texas Gulf Coast on 23 and 30 August, 2017 (Click to enlarge)

MODIS Today imagery from 23 August (pre-Harvey) (cropped) and 30 August (post-Harvey) (cropped), above, show an enormous increase in turbidity in the nearshore waters off the coast of Texas. Further, many of the rivers change their appearance to brown and flooding in the post-Harvey image. (River gauges in flood stage; Source)

A similar toggle using Suomi NPP VIIRS Imagery, from this site, also from 23 August and 30 August, is shown below. The increase in turbidity was due to a combination of strong winds and runoff from very heavy rainfall associated with the hurricane.

Suomi NPP True-Color imagery off the Texas Gulf Coast on 23 and 30 August, 2017 (Click to enlarge)

Suomi NPP VIIRS Products include a River Flood estimate, developed by Sanmei Li and others at George Mason University. The toggle below from RealEarth shows Suomi NPP VIIRS True Color at 1904 UTC, and the River Flood Product for the same time.

Suomi NPP VIIRS True-Color imagery off the Texas Gulf Coast, 1904 UTC on 30 August, 2017, and the Suomi NPP River Flood Product at the same time (Click to enlarge)

(Thanks to Bill Taylor and John Stoppkotte, NWS in N. Platte NE, for noting this!)

Canadian wildfire smoke over Quebec, Maine and the Canadian Maritimes

August 17th, 2017 |

GOES-16 Visible (0.64 µm, top) and Cirrus (1.37 µm, bottom) images [click to play MP4 animation]

GOES-16 Visible (0.64 µm, top) and Cirrus (1.37 µm, bottom) images [click to play MP4 animation]

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

Filaments of smoke aloft from Canadian wildfires were evident in GOES-16 “Red” Visible (0.64 µm) and Cirrus (1.37 µm) imagery (above; also available as a 24 Mbyte animated GIF) on 17 August 2017, drifting cyclonically eastward over Quebec, Maine and the Canadian Maritimes. The appearance of the smoke signature on Cirrus images was due to the fact that this spectral band is useful for detecting features composed of particles that are efficient scatterers of light (such as cirrus cloud ice crystals, airborne dust or volcanic ash, and in this case, smoke).

A comparison of GOES-16 “Clean” Infrared Window (10.3 µm) and Cirrus (1.37 µm) images (below; also available as a 21 Mbyte animated GIF) demonstrated that no smoke signature was seen on the infrared images (since smoke is effectively transparent at infrared wavelengths).

GOES-16 Infrared Window (10.3 µm, top) and Cirrus (1.37 µm, bottom) images [click to play MP4 animation]

GOES-16 Infrared Window (10.3 µm, top) and Cirrus (1.37 µm, bottom) images [click to play MP4 animation]

A more upstream view of the smoke feature was provided by a comparison of  Terra MODIS Visible (0.65 µm), Cirrus (1.375 µm) and Infrared Window (11.0 µm) images at 1626 UTC (below). Again, note the lack of a smoke signature in the Infrared image.

Terra MODIS Visible (0.65 µm), Cirrus (1.375 µm) and Infrared Window (11.0 µm) images [click to enlarge]

Terra MODIS Visible (0.65 µm), Cirrus (1.375 µm) and Infrared Window (11.0 µm) images [click to enlarge]

Depending on the altitude of these smoke filament features, daily composites of  Suomi NPP VIIRS true-color images covering the 5-day period of 12 August17 August (below) suggest that their source was either widespread fires in the Northwest Territories, or intense fires in British Columbia (which included pyroCb that injected smoke to very high altitudes).

Suomi NPP VIIRS daily true-color images [click to enlarge]

Suomi NPP VIIRS daily true-color images [click to enlarge]