Parameterization of size-resolved dust emission and validation with measurements

Abstract

A critical problem in dust research is to estimate size-resolved dust emission rates. Several dust schemes have been proposed but are yet to be rigorously tested against observed data. In the recent Japan-Australia Dust Experiment (JADE), size-resolved dust fluxes were measured. In this study, the JADE data are used to test a size-resolved dust scheme. Our aim is to examine whether the scheme has the capability to predict size-resolved dust fluxes, what the ranges of the scheme parameters are, and whether the scheme is sensitive to the parameters. The JADE data show that dust emission depends linearly on saltation flux and thus confirm the basic assumption of the scheme. The magnitudes of the scheme parameters are found to be consistent with those reported in earlier studies. The estimated size-resolved dust fluxes are in satisfactory agreement with the measurements, although considerable discrepancies remain and are difficult to rectify without speculative tuning of the scheme input parameters. The discrepancies have been traced back to the uncertainties in the parent soil particle size analyses and in the dust flux observations. Ensemble tests showed both model physics uncertainties and parameter uncertainties. It is proposed that the dust scheme under consideration is not as sensitive as previously suspected and is likely to perform well if the parameters are specified within a reasonably correct range. Show more