Today’s GeoXO Imager (GXI) synthetic water vapor transmittance (WVT) imagery off the east coast of Florida/Georgia revealed a series of clear-sky ripple-like features approximately 100 miles off the eastern seaboard (Figure 1). These features were moving toward the Florida coast in the dominant low-to-mid level northeasterly flow.
Although these ripples are reminiscent of gravity waves, their origin is not clear in this case; they are likely larger scale roll structures associated with shear in the marine environment.
Gravity waves were, however, clearly visible in real Flexible Combined Imager (FCI) WVT imagery over Africa earlier in the day (Figure 2). Gravity waves are frequently observed in this region north of the ITCZ as waves propagate out of convective complexes. These waves can be associated with airline turbulence as they propagate outward and upward away from their sources, so the ability to clearly see these waves in clear-sky regions is a benefit of the 0.91 µm channel coming to GXI. Figure 3 shows the same scene in the 7.35 µm water vapor channel, where the waves are still visible, but considerably less well defined.
Figure 2: Gravity waves from today in FCI WVT imagery over Africa. The waves appear as a series of dark ripples moving north near the center of the image, and likely originated with the ITCZ convection in the bottom-right corner of the image.
Figure 3: The gravity waves are still somewhat visible (though significantly less defined) in the FCI 7.35 µm low-level water vapor channel. The clarity of the feature in the 0.91 µm-derived WVT product (Figure 2) presents an opportunity for novel uses of the new GXI channel to identify these waves.
