Geoscience Reference
In-Depth Information
Chapter 9
Numerical Dust Models
Ina Tegen and Michael Schulz
Abstract Models of dust emission, transport and deposition are used as a tool to
understand the various aspects that control distributions and impacts of dust. While
global models of the dust cycle are used to investigate dust at large scales and long-
term changes, regional dust models are the ideal tool to study in detail the processes
that influence dust distribution as well as individual dust events. Simulating dust
emissions, which depend non-linearly on surface wind speed, is a critical issue in
dust transport models. Surface wind fields used to compute emission fluxes must
be available at appropriate resolution to resolve the processes responsible for dust
emissions. A major problem in model-based assessments of dust effects is that
atmospheric models are often unable to reproduce the small-scale wind events that
are responsible for a large part of dust emission. Recent satellite-retrieved surface
roughness data for desert regions considerably improve dust emission computations.
Model intercomparison studies highlight that the averages and seasonal variability
of vertically integrated mineral dust parameters like optical thickness and Ångstrom
exponent agree within a factor of two with observations. Less agreement is found
for surface concentration and deposition fields of mineral dust particles.
Keywords Dust models ￿ Emission ￿ Surface parameters ￿ Dust sources ￿
Meteorology ￿ Dust transport ￿ Deposition ￿ Optical properties ￿ Regional dust
models ￿ Global dust models
Search WWH ::




Custom Search