Protocols for Characterizing Aeolian Mass-Flux Profiles

We will present a protocol for characterizing aeolian mass-flux profiles with a focus on those obtained in natural aeolian environments. Three main areas of methodological inconsistencies are explored, using two field-based data sets to demonstrate the variability of the different methodological choices: 1) inconsistent representation of sediment trap elevations; 2) erroneous or sub-optimal regression analysis; and 3) inadequate or ambiguous bed elevation measurements. The protocol devised in this paper will permit results from different field- and laboratory-based studies to be comparable, is physically based, and seems to produce results that most closely represent the measured data. The recommended protocol suggests the following: 1) Measure vertical flux profiles with maximum number traps as feasible with bottom trap heights not exceeding 20 mm; 2) Repeat measurements of bed elevation before, during, and after data collection; 3) Use the geometric mean to represent trap centers; 4) When a trap is deployed at the bed (0 mm), approximate the bottom using aerodynamic roughness length; 5) Fit vertical mass-flux curves using a non-linear exponential fit; and 6) Plot vertical mass-flux so that height above the bed is independent (abscissa) of normalized mass-flux percentage (ordinate).