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Detailed Reference Information |
Miller, R.L., Perlwitz, J. and Tegen, I. (2004). Feedback upon dust emission by dust radiative forcing through the planetary boundary layer. Journal of Geophysical Research 109: doi: 10.1029/2004JD004912. issn: 0148-0227. |
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Large changes to the amount of airborne soil particles (or mineral dust aerosol) inferred from the climate record raise the question of whether radiative forcing by dust particles amplifies or else diminishes these changes. A previous study with an atmospheric general circulation model (AGCM) indicates that dust radiative forcing in the present-day climate reduces emission of dust into the atmosphere. Here, we interpret this reduction as an interaction between dust radiative forcing and the planetary boundary layer (PBL). By reducing sunlight incident upon the surface, dust decreases the turbulent flux of sensible heat into the atmosphere. This reduces turbulent mixing within the PBL, along with the downward transport of momentum to the surface, resulting in a decrease of surface wind speed and dust emission. We illustrate this mechanism by comparing the diurnal cycle of emission simulated by two versions of an AGCM, one containing dust radiative forcing, and the other with this forcing set to zero. At some of the most productive source regions, morning emission is reduced in proportion to the surface radiative forcing. We suggest that this negative feedback is underestimated by the AGCM. |
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BACKGROUND DATA FILES |
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Abstract |
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Keywords
Atmospheric Composition and Structure, Aerosols and particles (0345, 4801), Global Change, Climate dynamics, Meteorology and Atmospheric Dynamics, Boundary layer processes, Meteorology and Atmospheric Dynamics, Land/atmosphere interactions, Meteorology and Atmospheric Dynamics, Planetary meteorology (5445, 5739) |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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