Spatial distributions and seasonal cycles of aerosols in India and China seen in global climate-aerosol model S. V. Henriksson1, A. Laaksonen1,2, V.-M. Kerminen1, P. Räisänen1, H. Järvinen1, A.-M. Sundström3, and G. de Leeuw1,3 1Finnish Meteorological Institute, Helsinki, Finland 2Department of Applied Physics, University of Kuopio, Kuopio, Finland 3Department of Physics, University of Helsinki, Helsinki, Finland
Abstract. A climate-aerosol model is employed to study spatial and temporal variability
of aerosol properties over India and China for recent (year 2006) and future
conditions (year 2020) under different emission pathways. We present results
for aerosol mass concentration in different size classes and optical
properties for the five different aerosol species treated by the model.
Aerosol mass concentration and optical depth have significant contributions
from both anthropogenic and natural aerosols. Different species have maxima
in different regions, with the highest anthropogenic aerosol concentrations
found in Kolkata and elsewhere in the Ganges basin in India and on the
northern part of the east coast and in the Sichuan basin in China. In India,
natural aerosols have a maximum in the summer due to higher wind speeds,
whereas anthropogenic aerosols have a maximum in the winter due to less
efficient wet removal. Surface concentrations also tend to be higher in
winter due to the additional reason of lower average boundary layer height.
In China, seasonal cycles are weaker with natural aerosols having a maximum
in the spring and sulfate contribution to the aerosol optical depth (AOD)
being higher in the latter half of the year. MODIS AOD spatial distributions
are reproduced well by the model, except for the Ganges valley with high
absorption and for the Thar desert with high dust concentrations. Seasonal
cycles compare qualitatively well with MODIS measurements.
Citation: Henriksson, S. V., Laaksonen, A., Kerminen, V.-M., Räisänen, P., Järvinen, H., Sundström, A.-M., and de Leeuw, G.: Spatial distributions and seasonal cycles of aerosols in India and China seen in global climate-aerosol model, Atmos. Chem. Phys., 11, 7975-7990, doi:10.5194/acp-11-7975-2011, 2011.