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Impact of dust part...
Impact of dust particle non-sphericity on climate simulations
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- Raisanen, P. (författare)
- Illmatieteen Laitos,Finnish Meteorological Institute (FMI)
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- Haapanala, P. (författare)
- Helsingin Yliopisto,University of Helsinki
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- Chung, C. E. (författare)
- Gwangju Institute of Science and Technology
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- Kahnert, Michael, 1968 (författare)
- Chalmers tekniska högskola,Chalmers University of Technology
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- Makkonen, R. (författare)
- Universitetet i Oslo,University of Oslo,Helsingin Yliopisto,University of Helsinki
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- Tonttila, J. (författare)
- Illmatieteen Laitos,Finnish Meteorological Institute (FMI),Helsingin Yliopisto,University of Helsinki
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- Nousiainen, T. (författare)
- Helsingin Yliopisto,University of Helsinki
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(creator_code:org_t)
- 2012-12-11
- 2013
- Engelska.
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Ingår i: Quarterly Journal of the Royal Meteorological Society. - : Wiley. - 0035-9009 .- 1477-870X. ; 139:677, s. 2222-2232
- Relaterad länk:
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http://dx.doi.org/10...
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https://research.cha...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- Although mineral aerosol (dust) particles are irregular in shape, they are treated as homogeneous spheres in climate model radiative transfer calculations. Here, we test the effect of dust particle non-sphericity in the ECHAM5.5-HAM2 global aerosol-climate model. The short-wave optical properties of the two insoluble dust modes in HAM2 are modelled using an ensemble of spheroids that has been optimized to reproduce the optical properties of dust-like aerosols, thereby providing a significant improvement over spheres. First, the direct radiative effects (DRE) of dust non-sphericity were evaluated diagnostically, by comparing spheroids with both volume-equivalent and volume-to-area (V/A) equivalent spheres. In the volume-equivalent case, the short-wave DRE of insoluble dust at the surface and at the top of the atmosphere (TOA) was slightly smaller (typically by 3-4%) for spheroidal than for spherical dust particles. This rather small difference stems from compensating non-sphericity effects on the dust optical thickness and asymmetry parameter. In the V/A-equivalent case, the difference in optical thickness was virtually eliminated and the DRE at the TOA (surface) was approximate to 20% (approximate to 13%) smaller for spheroids than for spheres, due to a larger asymmetry parameter. Even then, however, the global-mean DRE of non-sphericity was only 0.055 W m(-2) at the TOA and 0.070 W m(-2) at the surface. Subsequently, the effects of dust non-sphericity were tested interactively in simulations in which ECHAM5.5-HAM2 was coupled to a mixed-layer ocean model. Consistent with the rather small radiative effects noted above, the climatic differences from simulations with spherical dust optics were generally negligible.
Ämnesord
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Klimatforskning (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Climate Research (hsv//eng)
Nyckelord
- MODEL ECHAM5-HAM
- INDEPENDENT SPHERES
- climate modelling
- LIGHT-SCATTERING
- dust particles
- MINERAL AEROSOL
- aerosols
- TROPOSPHERIC AEROSOLS
- ABSORPTION
- OPTICAL-PROPERTIES
- SENSITIVITY
- radiative transfer
- SPHEROIDS
- NONSPHERICAL ICE PARTICLE
- non-sphericity
Publikations- och innehållstyp
- art (ämneskategori)
- ref (ämneskategori)
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