Dust devil height and spacing with relation to the martian planetary boundary layer thickness

DD spacing was measured using nearest neighbor statistics, following the assumption that because convection cell widths have been measured to be ∼1.2 ± 0.2h (Willis, G.E., Deardorff, J.W. [1979]. J. Geophys. Res. 84(C1), 295-302), a preference for DD formation at vertices of convection cells intersections could be used to estimate the PBL height. During local spring and summer, the DD average nearest neighbor (ANN) ranged from ∼1 to 2h, indicating that DD spacing does indeed correlate with PBL height. However, this result is complicated by two factors: (1) convection cell spacing estimates indicate that the observed DD distributions undersample the possible grid of cell vertices in each CTX image, and (2) comparison of the ANN with a random distribution shows that the most closely-spaced DD distributions exhibit some clustering; we propose that this clustering demonstrates that many of the observed DDs are located along convection cell walls, in addition to cell vertices.