Abstract
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.
Highlights
Atmospheric aerosol is an important forcing factor in the global climate system
In case 5 we artificially tune a parameter of wind stress correction factor, which is a constant number over the globe and reduces the threshold wind friction velocity proportionally
An improvement on the dust emission scheme is included in the global aerosol-climate modeling system ECHAM5HAM
Summary
Atmospheric aerosol is an important forcing factor in the global climate system. considerable uncertainties still exist in the estimates of direct and indirect effects of aerosols on the earth radiation budget and global climate changes (IPCC, 2007). The model can appropriately estimate the global distribution, transportation and climate impact of dust aerosols. The parameterization of dust emission in ECHAM5-HAM is still rather crude. Some key parameters such as the surface roughness, soil moisture and soil properties at various locations are not very well included. Further modifications on the dust emission scheme are expected in order to simulate the mineral dust aerosols more realistically. We present an improved dust emission scheme for application into the ECHAM5-HAM, which incorporates updates of the surface aerodynamic roughness length, soil moisture and East-Asian soil properties. Results from model simulations with the improved scheme as well as comparisons with the previous simulation and measurements are shown in Sect.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
