Fig. 3: Mixed layer heights over dune fields.
a An example mixed layer height H annual climatology for the Rub Al Khali measured using CALIPSO for 2006–2019. Monthly means and standard deviations given (n = 222). b H and measured dune wavelengths x for 34 dune fields in the geometry data set, means (red dots with black outlines) and standard deviations (red lines) for both measurements are shown, as is the Pearson’s correlation coefficient rHx and the identity H = x. If two characteristic dunes are identified in a tile, only the larger one is included in the averaging for this plot. c An example of the H extraction from CALIPSO (pictured) over the Rub Al Khali. As the satellite passes over the dune field (gray region), the CALIPSO (green line) scan of the atmosphere detects high backscatter β from aerosols in the mixed layer relative to the free atmosphere above (blue map, 5-km horizontal resolution). The mean difference (red line) of the delineation between high and low β, Z, (purple line) and elevation η (gray region) for the scan constitutes one H value20.
