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| Regional Climate and Air
Quality |
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Principal Investigators
MIT:
M.Molina, R.Prinn, E.Eltahir
ETH: C.Shar, H.Davies
UT: A.Sumi,
H.Akimoto, S.Kodo
EPFL: M.Rossi, H.van den Bergh
Recent
research has made it clear that atmospheric pollution in the form of
gaseous and aerosol constituents can substantially influence
regional and global climate. Thus policy decision regarding climate
need to take into account air pollution policies and vice-versa. The
interaction between meteorological and chemical components of the
system is two-way: the regional circulation, cloud and precipitation
patterns determine the transport and washout of the chemical
species, while the presence of atmospheric pollutants feeds back to
the regional climate through radiative and cloud-microphysical
processes.
Goals/Objectives
- To integrate existing activities from the fields of regional
climate modeling, air pollution modeling, and laboratory studies
of air and aerosol chemical reactions to better inform ongoing
policy studies.
- To improve the representation of surface hydrology and
precipitation processes in regional models.
- To find, describe and understand from a fundamental point of
view novel heterogeneous chemical processes taking place at the
gas/solid or gas/liquid interface.
- To confirm the experimental results by several independent
methods in order to afford a wide range of experimental parameters
and to minimize artifacts or spurious effects.
- The integration of the meteorological and chemical activities
detailed above, using a Regional Atmospheric Transport and
Chemistry (RATCH) model.
The major scientific goals
are:
- To understand better the ways in which regional climate change
can affect regional air quality.
- To understand better the ways in which radiatevely important
species produced on the regional scale can affect climate on
regional to global scales
- To provide a mechanism for timely integration of the above
laboratory studies of chemical reaction into air quality modeling
and setting priorities for the laboratory studies through
exploratory modeling studies
- To understand the two-way feedbacks between regional air
quality and climate
- Reaction probabilities for heterogeneous chemistry processes
measured with different techniques in each of the laboratories
will be intercompared and will be provided as input to the
regional atmospheric chemistry model
- Prediction of gases and aerosols and regional scale for input
to ecosystem and human health studies
- Objective analyses of proposed air pollution and climate
policies and measures
- Better tools that are designed to study regional impacts of
any global change
- Better understanding of the mechanisms responsible for the
response of the soil hydrology in mid-latitudes to doubling of
carbon dioxide
- Better understanding of the impact of changes in vegetation
and wintertime snow cover on the regional climate of
mid-latitudes.
Results/Findings
- Found and studied a “slow” heterogeneous chemical reaction
that may be of importance in areas of intense agriculture or where
ammonia emissions are important.
- Soot from combustion sources when interacting with NO2 may
result in the formation of HONO which is a trigger of
photochemical smog formation. The sources of HONO are not clear.
The project has highlighted the influence of ht type of soot ant
its reactivity as a function of combustion stoichiometry
- Characterized the ice surface of Cirrus clouds and contrail
particles formed in the upper troposphere where the greenhouse
effect is the largest.
- Investigated the mechanism of atmospheric oxidation of
aromatic compounds, particularly toluene. This is an important
process in smog formation in polluted cities.
- Started investigations of chemical properties of soot
particles, in particular their susceptibility to be oxidized by
the hydroxyl radical.
- Determination of characterization of regional-scale climate
predictability
- Hydrological feedback processes between the soil and
atmosphere, and in particular between soil moisture and
precipitation, in order to assess the predictability of regional
climate and to evaluate the impacts of climate change on water
resources. Results demonstrate that precipitation in summertime
mid-latitude climates depend heavily upon the soil-moisture
contents.
- Improvement of the representation of surface hydrology and
precipitation processes in regional
models.
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