South Sandwich Islands lee waves

January 16th, 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 created using Geo2Grid (above) revealed long trails of lee waves extending northeastward from many of the South Sandwich Islands on 16 January 2021. These lee waves were generated by strong southwesterly winds within the marine boundary layer interacting with the topography of the islands — wind speeds had increased across that portion of the South Atlantic Ocean, in response to the tight pressure gradient between high pressure north of the islands and a deepening area of low pressure southeast of the islands (MSLP analyses).

A toggle between two NOAA-20 VIIRS True Color RGB images as viewed using RealEarth (below) provided a higher-resolution view of the lee waves extending from the island chain.

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

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

Many of these islands contain active volcanoes, which frequently produce plumes (which are primarily comprised of steam). A closer look at the lee waves emanating from one of the northernmost islands (below) appeared to suggest that a brighter white volcanic plume existed within the train of waves.

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

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