scholarly journals Fingerprints of Arctic aerosol-cloud-turbulence interactions in conserved variable space

2021 ◽  
Author(s):  
Roel Neggers ◽  
Jan Chylik
Keyword(s):  
Aerosol Cloud ◽  
Arctic Aerosol ◽  
Variable Space

scholarly journals Characterization of the cloud microphysical and optical properties and aerosol-cloud interaction in the Arctic from in situ ground-based measurements during the CLIMSLIP-NyA campaign, Svalbard

2017 ◽  
Author(s):  
Gwennolé Guyot ◽  
Frans Olofson ◽  
Peter Tunved ◽  
Christophe Gourbeyre ◽  
Guy Fevbre ◽  
...  
Keyword(s):  
Indirect Effect ◽  
Climate Models ◽  
Droplet Diameter ◽  
Arctic Region ◽  
The Arctic ◽  
Blowing Snow ◽  
Aerosol Cloud ◽  
Arctic Aerosol

Abstract. This study will focus on cloud microphysical and optical characterization of three different types of episodes encountered during the ground based CLIMSLIP-NyA campaign performed in Ny-Alesund, Svalbard: the Mixed Phase Cloud (MPC), snow precipitation and Blowing Snow (BS) events. These in situ cloud measurements will be combined with aerosol measurements and air mass backtrajectory simulations to qualify and parameterize the arctic aerosol cloud interaction and to assess the influence of anthropogenic pollution transported into the Arctic. The results show a cloud bimodal distribution with the droplet mode at 10 µm and the crystal mode centered at 250 µm, for the MPC cases. The precipitation cases presents a crystal distribution centered around 350 µm with mostly of dendritic shape. The BS cases show a higher concentration but smaller crystals, centered between 150 and 200 µm, with mainly irregular crystals. A polluted case, where aerosol properties are influenced by anthropogenic emission from Europe and East Asia, was compared to a clean case with local aerosol sources. These anthropogenic emissions seem to cause higher Black Carbon, aerosol and droplet concentrations, a more pronounced accumulation mode, smaller droplet sizes and a higher activation fraction Fa. Moreover, the activation diameter decreases as the droplet diameter increases and Fa increases showing that smaller particles are activated and droplets grow when the aerosol number decreases. This is in agreement with the first (Twomey) and second (Albrecht) aerosol indirect effect. The quantification of the variations of droplet concentration and size leads to IE (Indirect Effect) and NE (Nucleation Efficiency) coefficients values around 0.2 and 0.43, respectively. These values are close to those found by other studies in the arctic region which confirms these parameterizations of arctic aerosol-cloud interaction in climate models.

Aerosol-cloud-climate interactions in the climate model CAM-Oslo

2008 ◽  
Author(s):  
Alf KirkevÃ¥g ◽  
Trond Iversen ◽  
Øyvind Seland ◽  
Jens Boldingh Debernard ◽  
Trude Storelvmo ◽  
...  
Keyword(s):  
Climate Model ◽  
Aerosol Cloud ◽  
Climate Interactions

The radiative effect of an aged, internally mixed Arctic aerosol originating from lower-latitude biomass burning

Tellus B ◽  
2009 ◽  
Vol 61 (4) ◽  
Author(s):  
Ann-Christine Engvall ◽  
Johan Ström ◽  
Peter Tunved ◽  
Radovan Krejci ◽  
Hans Schlager ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Lower Latitude ◽  
Radiative Effect ◽  
Arctic Aerosol

Numerical Solution of a Nonlinear Diffusion Model for Soybean Hydration with Moving Boundary

2015 ◽  
Vol 11 (5) ◽  
pp. 587-595 ◽  
Author(s):  
Douglas J. Nicolin ◽  
Gisleine E. C. da Silva ◽  
Regina Maria M. Jorge ◽  
Luiz Mario M. Jorge
Keyword(s):  
Differential Equation ◽  
Diffusion Model ◽  
Nonlinear Diffusion ◽  
Numerical Scheme ◽  
Moving Boundary ◽  
Grid Method ◽  
Variable Diffusivity ◽  
Variable Space ◽  
Diffusive Fluxes ◽  
Moisture Profiles

Abstract Variable diffusivity and volume of the grains are taken into account in the diffusion model that describes mass transfer in soybean hydration. The variable space grid method (VSGM) was used to consider the increase in grain size, and the diffusivity was considered an exponential function of the moisture content. An equation for the behavior of the grain radius as a function of time was obtained by global mass balance over the soybean grain and the differential equation considered that the increase in radius happens due to the influence of the convective and diffusive fluxes at the surface of the grains. The model was solved by an explicit numerical scheme which presented satisfactory results. The results showed the behavior of moisture profiles obtained as a function of time and radial position and also showed how the grain radius increased with time and changed the solution domain of the diffusion equation.

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