Water changes over the Gulf of Mexico from Ian

September 30th, 2022 |

Polar-Orbiting satellites flying over Florida viewed remarkable changes in water quality from before and after the passage of Hurricane Ian. Imagery from Suomi-NPP, for example, from 25 September and 30 September, toggled below (imagery derived from the VIIRS Today website), shows a large increase in turbidity in the Gulf (and over the Atlantic off the coast of eastern Florida) as well as discharge plumes from near Fort Myers and from points to the south.

VIIRS Today True-Color imagery from Suomi-NPP, 25 and 30 September 2022 (Click to enlarge)

True-color imagery from the Aqua MODIS instrument (below), taken from the MODIS Today website, also shows the dramatic changes (between 25 September and 30 September) in turbidity and water quality off the southwestern coast of Florida.

MODIS True-color imagery over the southeastern Gulf of Mexico before (25 September) and after (30 September) Hurricane Ian

Note: Hurricane Wilma caused a similar increase in turbidity (link).

Thanks to RIck DiMaio, Lewis University, for pointing this out!

01 October Update: One feature of interest was a small cyclonic eddy that developed along the end of a long curved filament of cyan-colored turbidity which was wrapping around the Florida Keys — shown in GOES-16 (GOES-East) True Color RGB images from the CSPP Geosphere site  (below).

GOES-16 True Color RGB images [click to play MP4 animation]

Rapid ice growth in Lake Erie

January 31st, 2022 |

GOES-16 “Red” Visible (0.64 µm) images, with surface wind barbs (knots) plotted in cyan [click to play animated GIF | MP4]

GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed the widespread coverage of ice across Lake Erie on 31 January 2022. Surface winds were generally light across the region, minimizing wind stress on the pack ice. A careful inspection of the imagery revealed some straight pathways cut through the ice by US Coast Guard icebreakers.

An Aqua MODIS True Color RGB image from the MODIS Today site (below) provided a higher-resolution view of the linear icebreaker paths in the western portion of the lake (where the ice was generally thicker).

Aqua MODIS True Color RGB image [click to enlarge]

The entire icebreaker channel was apparently completed sometime before sunrise on 31 January — the western portion was evident in a Sentinel-1A Synthetic Aperture Radar (SAR) Normalized Radar Cross Section (NRCS) image (source) at 2324 UTC on 30 January, and its eastward continuation was seen in a RCM-1 SAR NRCS image at 1136 UTC image on 31 January (below).

SAR NCRS images from Sentinel-1A at 2324 UTC on 30 January and from RCM-1 at 1136 UTC on 31 January [click to enlarge]

A toggle between GOES-16 Visible images at 1801 UTC on 29 January and 31 January (below) showed the marked increase in ice coverage during that 48-hour period.

GOES-16 “Red” Visible (0.64 µm) images at 1801 UTC on 29 January and 31 January 2022 [click to enlarge]

In fact, a GLERL plot of current Lake Erie ice coverage compared to the historical average (below) showed that the percentage of ice cover had recently become well above average for the date.

Plot of current Lake Erie ice coverage (black) compared to the historical average (red) [click to enlarge]

Early November with little snow

November 7th, 2021 |
BRDF Imagery from MODIS, 7 November 2021 (Click to enlarge)

A MODIS-based true-color cloud-free image, above, from SSEC’s Real Earth (link) shows a distinct lack of snow cover — for early November!!! — over the USA and Canada. These BRDF (Bidirectional Reflectance Distribution Function) fields account for sun angle, viewing angle and surface type; data over the past 16 days are used in this computation. Monitor these fields at the RealEarth link in the coming weeks to see the inevitable (albeit delayed!) increase in snow cover over North America!

Consolidation of ice within Green Bay

March 4th, 2021 |

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed the wind-driven consolidation of ice within Green Bay during the 03 March04 March 2021 period. Northerly winds in the wake of a cold frontal passage on 03 March led to the fracturing of land-fast ice in the far northern portion of Green Bay — this ice then began drifting south-southwestward.

By sunrise on 04 March, GOES-16 Visible images indicated that the fractured ice had continued to drift farther southward overnight, eventually merging with the land-fast ice that had been covering the southern half of Green Bay; overnight low temperatures in the upper teens to low 20s F likely aided this merger process. Note that some filaments of ice had also migrated through gaps between islands, drifting southward across far western Lake Michigan (just off the coast of Wisconsin).

A toggle between 250-meter resolution Aqua MODIS True Color RGB images (source) on the 2 days is shown below.

Aqua MODIS True Color RGB images [click to enlarge]

Aqua MODIS True Color RGB images [click to enlarge]

As an aside, farther inland the tornado damage path from an EF3 tornado in northeastern Wisconsin was still evident, 13.5 years later (below).

Aqua MODIS True Color RGB images [click to enlarge]

Aqua MODIS True Color RGB images [click to enlarge]