Dust over the US Central Plains and Gulf of Mexico
15 January 2021 15:00-16 January 23:50 UTC
A major dust outbreak over the American Central Plains in mid-January 2021, could be clearly seen in GOES imagery.
10 June 2022
19 January 2021
By Jochen Kerkmann (EUMETSAT) and Ivan Smiljanic (CGI)
Figure 1 is the GOES-16 Dust RGB 10-minute interval animation over the Central Plains, starting at around 15:30 UTC, strong northerly winds picked up dust over eastern Colorado. The dust was carried southward across Oklahoma and Texas towards the Gulf of Mexico.
On the following day, the dust plume began to flow off the Texas coast and over the Gulf of Mexico by 06:00 UTC, and, although the plume signature began to diminish in the Dust RGB images after sunrise, it was very apparent in Geocolor (True Color) RGB imagery. The GOES-17 Geocolor RGB product (Figure 2) shows the dust cloud on 16 January 15:00 UTC (see red arrows). The GOES-17 image shows a stronger signal than GOES-16 from forward scattering at 15:00 UTC due to the sunrise in the East, while the satellite was over Pacific in the west.
Even though near-IR 1.3 μm spectral region experience strong absorption of water vapour, in the drier atmosphere the NIR1.3 channel can detect aerosols (i.e. dust) in mid and low altitudes. In this case, the dust was detected as a grey cloud (reflectance range 1-2%) traveling from Colorado towards Texas during the day on 15 January (Figure 3).
A day later the dust was already advected into the region of more moisture (Gulf of Mexico), so was only vaguely detected by the NIR1.3 channel. The dry-to-moist border, i.e. bright-to-dark grey gradient cutting though southern Texas, can be clearly seen in Figure 4.
GOES imagery comparison
Figure 4: GOES-16 v GOES-17 view on the dust, through ABI NIR1.3 channel, 15 January, 18:00 UTC (noon in Texas). Imagery visualised within 0-3% reflectivity range, Gamma correction 0.5. More slant view of GOES-17 provides less sensitivity to low- to mid-level dust (aerosol) detection. Dry-moist boundary annotated by a blue line, lakes around state of Texas encircled in yellow.
