Ecoinformatics Problems of Global Climate Change - New Ecoinformatics Tools in Environmental Science: Applications and Decision-making - page 455

precipitation are determined by a variation of the dynamical hydrological cycle with
a temperature change by the aerosol direct and indirect effect rather than the second
indirect effect itself. The global mean direct and indirect anthropogenic ARFs at the
tropopause by anthropogenic aerosols are calculated to be 0.9Wm − 2 ,

respectively. It has been suggested therefore that aerosol particles reduce the
increase in the SAT due to GHGs approximately by 40 %, on the global mean.
Quaas et al. (2004) have used three ensembles of simulations with the LMDZ
general circulation model developed at the Laboratoire de M

− 0.1 and −

è t è orologie Dynamique

to assess the radiative impacts of ve GHGs (CO 2 ,CH 4 ,N 2 O, CFC-11, and CFC-

12), as well as sulphate aerosols for the time period 1930 1989 (sea surface tem-

perature was prescribed). It has been shown that the GHGs concentration increase
results in a reduction of clouds at all atmospheric levels, thus decreasing the total
greenhouse effect in the longwave spectrum and increasing absorption of solar
radiation by reduction of cloud albedo. Since different changes in high- (decrease)
and low-level (increase) cloudiness have been obtained, the

-

final result was a
slightly positive net effect due to cloudiness changes. The total aerosol effect
including the aerosol direct and indirect effects remains strongly negative.
Lohmann (2004) has studied the global impact of aerosols on the riming rate of
snow crystals of different shapes with cloud droplets in stratiform clouds using the
AGCM general circulation model to answer the question: can anthropogenic
aerosols decrease the snowfall rate? The

final answer was that in accordance with
the present-day simulation there had been a slight increase of the snowfall rate over
pre-industrial times.
The opinion expressed by Jacobson et al. (2002) that control of emissions of BC
aerosol and organic matter to the atmosphere due to fossil fuel burning can become
an ef cient method of slowing the global warming, has caused a hot discussion.

Feichter et al. (2003) noted this connection that according to estimates obtained by
Jacobson, emissions to the atmosphere of carbon aerosol (BC and organic carbon,
OC) due to fossil fuel burning can cause an increase of global average SAT by
0.35 K. However, there is doubt with respect to grounds for conclusions in this
study connected with, that the emissions under discussion contain also sulphur
dioxide (which determines the formation of sulphate aerosol). Besides, emissions
affect both absorption and scattering of shortwave radiation, which they can cause
both warming and cooling. Still, more important is the fact that the climate model
GATOR-GCMM used by Jacobson has not been tested for adequacy by comparing
with other models and with observational data, which is necessary, especially since
calculations for 6 years cannot ensure a simulation of an equilibrium climate.
Penner (2003) has made some comments.
Chock et al. (2003) have made remarks on the results of Jacobson (2002)
concerning the adequacy of the applied climate model, reliability of input infor-
mation, and substantiation of the needed ecological policy. As for the input
information, it was assumed that annual emissions of BC and OC constituted 6.4
and 10.1 TgC year − 1 . The assumed ratio OM:BC = 3.1:1 is equivalent to global
emissions of OM and OM-submicron aerosol reaching 19.9 and 15.9 TgC year − 1 ,
respectively, that is, much higher than the estimates mentioned above. Besides,