A parameterization of cirrus cloud formation: Homogeneous freezing of supercooled aerosols
Bernd Kärcher,Ulrike Lohmann +1 more
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In this paper, the number of ice crystals formed via homogeneous freezing of aqueous solution droplets is rather insensitive to details of the aerosol size distribution, but increases rapidly with updraft velocity and decreases with temperature.Abstract:
[1] The nucleation and initial growth of ice crystals in cirrus clouds at low (<235 K) temperatures prevailing in the upper troposphere and in the tropopause region is theoretically considered. The analysis explains the dependence of the number density of ice crystals on the vertical velocity and temperature seen in numerical simulations of cirrus formation when the timescale of depositional growth of the pristine ice particles is fast compared to the timescale of the freezing event. In such cases, applicable in many situations, the number of crystals formed via homogeneous freezing of aqueous solution droplets is rather insensitive to details of the aerosol size distribution, but increases rapidly with updraft velocity and decreases with temperature. The derived parameterization is validated with parcel model simulations, and its applicability for use in climate models is discussed. The potential role of aerosol size and heterogeneous freezing processes in altering the predicted cirrus properties is briefly addressed.read more
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References
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Journal ArticleDOI
Oceanic phytoplankton, atmospheric sulphur, cloud albedo and climate
TL;DR: The major source of cloud-condensation nuclei (CCN) over the oceans appears to be dimethylsulphide, which is produced by planktonic algae in sea water and oxidizes in the atmosphere to form a sulphate aerosol as mentioned in this paper.
Journal ArticleDOI
Aerosols, cloud microphysics, and fractional cloudiness.
TL;DR: Increases in aerosol concentrations over the oceans may increase the amount of low-level cloudiness through a reduction in drizzle—a process that regulates the liquid-water content and the energetics of shallow marine clouds—to contribute to a cooling of the earth's surface.
Journal ArticleDOI
Water activity as the determinant for homogeneous ice nucleation in aqueous solutions
TL;DR: This work shows from experimental data that the homogeneous nucleation of ice from supercooled aqueous solutions is independent of the nature of the solute, but depends only on the water activity of the solution, and presents a thermodynamic theory for homogeneous ice nucleation, which expresses the nucleation rate coefficient as a function of water activity and pressure.
Journal ArticleDOI
Influence of Cirrus Clouds on Weather and Climate Processes: A Global Perspective
TL;DR: In this paper, the authors reviewed and documented the current understanding and knowledge of the composition and structure of cirrus clouds and the radiative properties of clouds as they relate to weather and climate processes.
Book
Fundamentals of atmospheric modeling
TL;DR: In this paper, the authors propose numerical solutions to partial differential equations and finite-differencing the equations of atmospheric dynamics, including boundary-layer and surface processes, and Radiative energy transfer.