Saharan Air Layer plume over the Atlantic Ocean

September 20th, 2019 |

Saharan Air Layer product [click to play animation | MP4]

GOES-16 “Split Window” Saharan Air Layer product [click to play animation | MP4]

GOES-16 (GOES-East) Split Window images (above) showed a large plume of the Saharan Air Layer (SAL) that moved westward off the coast of Africa then westward and northwestward across the eastern and central Atlantic Ocean during the 15-20 September 2019 period.

On 20 September, the hazy SAL plume could be easily seen in Full Disk GOES-16 True Color Red-Green-Blue (RGB) images from the AOS site (below).

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

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

The SAL plume was also apparent in True Color RGB images from Suomi NPP and NOAA-20 as viewed using RealEarth (below).

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

A comparison of GOES-16 CIMSS Natural Color RGB, Aerosol Optical Depth and Dust Detection product images from 1500-1900 UTC on 20 September (below) revealed AOD values as high as 0.5 within the hazy dust-laden SAL plume; the Dust Detection product indicated large areas of Low- to Medium-Confidence dust (with isolated pockets of High Confidence).

GOES-16 CIMSS Natural Color RGB, Aerosol Optical Depth, and Dust Detection product [click to play animation | MP4]

GOES-16 CIMSS Natural Color RGB, Aerosol Optical Depth, and Dust Detection product [click to play animation | MP4]


On a side note, the Full Disk True Color shown above images revealed 3 different types of solar backscatter: a small spot of very bright sun glint off the water of the Amazon River and its tributaries, which moved from east to west (below)

GOES-16

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

along with 2 separate (and larger) areas of more diffuse solar backscatter, which propagated from west to east: the first (possibly a 180º-42º=138º or “rainbow” backscatter) appeared about midway between the Equator and the southern tip of South America — and the second  (a 180º backscatter) appeared farther north, closer to the Equator, slightly later in time (this type of solar backscatter was previously discussed here). These 3 solar backscatter features can also be seen in a rocking animation below.

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

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

Thanks to Fred Wu (NOAA/NESDIS) and Steve Miller (CIRA) for providing further insight regarding the nature of the 2 larger types of solar backscatter.

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