Open AccessSensitivity studies of the effect of increased aerosol concentrations and snow crystal shape on the snowfall rate in the Arctic
Author(s) -
Lohmann U.,
Zhang J.,
Pi J.
Publication year - 2003
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2003jd003377
Subject(s) - snow , aerosol , environmental science , atmospheric sciences , ice crystals , coalescence (physics) , drizzle , precipitation , liquid water content , accretion (finance) , arctic , mesoscale meteorology , supersaturation , materials science , meteorology , cloud computing , geology , physics , astrophysics , astrobiology , thermodynamics , oceanography , computer science , operating system
The mesoscale model GESIMA is used to simulate microphysical properties of Arctic clouds and their effect on radiation. Different case studies during the FIRE ACE/SHEBA project show that GESIMA is able to simulate the cloud boundaries, ice and liquid water content, and effective radii in good agreement with observations. For two different aerosol scenarios, the simulation results show that the anthropogenic aerosol can alter microphysical properties of Arctic clouds, and consequently modify surface precipitation. Borys et al. [2000] proposed that anthropogenically induced decreases in cloud droplet size inhibit the riming process. On the contrary, we find that the accretion of snow crystals with cloud droplets is increased in the polluted cloud owing to its higher cloud droplet number concentration. Instead, the autoconversion rate of cloud droplets and accretion of drizzle by snow decreases caused by the shutdown of the collision‐coalescence process in the polluted cloud. The amount of precipitation reaching the surface as snow depends crucially on the crystal shape. If aggregates are assumed, then a tenfold increase in aerosol concentration leads to an increase in accumulated snow by 40% after 7 hours of simulation whereas the snow amount decreases by 30% when planar crystals are assumed because of the larger accretion efficiency of snow crystals with cloud droplets in case of aggregates.