An improvement on the dust emission scheme in the global aerosol-climate model ECHAM5-HAM T. Cheng1,3, Y. Peng1,4, J. Feichter1, and I. Tegen2 1Max-Planck-Institute for Meteorology, Bundesstr. 53, 20146, Hamburg, Germany 2Leibniz-Institute for Tropospheric Research, Permoserstrasse 15, 04318 Leipzig, Germany 3Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China 4Canadian Centre for Climate Modeling and Analysis, 3964 Gordon Head Road, Victoria, B.C., V8N 3X3, Canada
Abstract. Formulation of the dust emission scheme in the global aerosol-climate
modeling system ECHAM5-HAM has been improved. Modifications on the surface
aerodynamic roughness length, soil moisture and East-Asian soil properties
are included in the parameterization, which result in a large impact on the
threshold wind friction velocity for aeolian erosion and thus influence the
simulated dust emission amount. The annual global mean of dust emission in
the year 2000 is reduced by 76.5% and 2.2%, respectively, due to
changes in the aerodynamic roughness length and the soil moisture. An
inclusion of detailed East-Asian soil properties leads to an increase of
16.6% in the annual global mean of dust emission, which exhibits mainly
in the arid and semi-arid areas of northern China and southern Mongolia.
Measurements of the surface dust concentrations are collected in remote
marine sites globally and in dust source regions of East Asia. The averaged
relative differences between model results and measurements are reduced from
17% to 12% in global remote marine sites and from 69% to 30% in
East Asia, by including the improvements. Comparisons between model results
and available measurements verify a more realistic dust
distribution with the improved emission scheme.
Citation: Cheng, T., Peng, Y., Feichter, J., and Tegen, I.: An improvement on the dust emission scheme in the global aerosol-climate model ECHAM5-HAM, Atmos. Chem. Phys., 8, 1105-1117, doi:10.5194/acp-8-1105-2008, 2008.