Atmospheric Aerosols as Indicators of Global Biogeochemical Changes

1
Atmospheric Aerosols as Indicators of Global
Biogeochemical Changes
Rudolf Husar
Washington UniversitySt. Louis, USA
Draft Presentation Prepared for the Induction
into the Hungarian Academy of Sciences
Budapest, June 23, 1998
2
The Physiology and Health Care of the Earth
System

• The physicians evaluate a patients health by
  measuring the temperature, pulse rate, the
  cholesterol level and other vital signs. For
  diagnosis, doctors use many tools, like x-ray
  images, ultrasound scans, usually in combination.

3
The Earth is also like a living organism.
According to the British scientist James
Lovelock, it has become necessary to monitor the
health of planet Earth. The reason is that the
physical and chemical state of the Earths
environment is constantly changing.
The Earth is physically aging, and at the same
time evolution is changing the biosphere. Some of
the changes occur slowly in a steady fashion and
they are foreseeable. However, many
bio-geochemical changes occur quickly,
unexpectedly, and they unevenly distributed in
space and time. From human point of view, many
of these changes are catastrophic events.
Some of the changes, short and long term, are
caused by human activites and therefor can be
influenced by control actions
4
Human Sensory-Motor Response to Changes
Regardless whether the Earth is considered
healthy or sick, the inevitable and
unforeseeable environmental changes require the
following major steps
Decision making, action (management)
Reasoning and explaining (sciences)
Sensing and recognition (monitoring)

The above three steps are the necessary
conditions for sustainable development. This is
logical since all living organisms use this type
of sensory-motor feedback to maintain their
existence.
5
DigitalEarth
6
Sensing and Monitoring
Todays earth scientists evaluate the physiology
of planet earth also by monitoring the
temperature, carbon dioxide, ozone, biomass,
cloudiness, and many other paramters as the vital
signs of the interconnected Earth System. The
observational instruments of earth sciences
include thermometers, chemical sampling analysis
of air, land and water, as well as earth
observing satellites. Dust storms, forest fires,
volcanic emissions and anthropogenic fuel
combustion are major biogeochemical processes
that are visualized by aerosols.
7

Major Biogeochemical Processes Visualized by
Aerosols
Dust storms
Fires
Volcanoes
Anthropogenic pollution
These processes are producing visible aerosols in
form of dust, smoke, and haze. The quantity and
spatial-temporal distribution of dust and smoke
and haze can be used to characterize the flow of
substances through the atmosphere.
8
Just like the human eye, satellite sensors detect
the total amount of solar radiation that is
reflected from the earths surface (Ro) and
backscattered by the atmosphere from aerosol,
pure air, and clouds. A simplified expression for
the relative radiatioin detected by a satellite
sensor (I/Io) is
Satellite Detection of Aerosols
I / Io Ro e-? (1- e-?) P
where ? is the aerosol optical thickness and P
the angular light scattering probability.
Today, geo-synchronous and polar orbiting
satellites can detect different aspects of
aerosols over the globe daily.
9

Explaining Change
The basic elements of life including carbon,
nitrogen, phosphorus, calcium are in constant
circulation between the earths major
environmental compartments atmosphere,
hydrosphere, lithosphere, and biosphere. These
earths compartments remain in balance as long as
the rate of flow of matter and energy in and out
of the compartments is unchanged.
Changes in the environmental compartments will
occur if the circulation (in and out flow) of the
substances is perturbed. For example, the
concentration of atmospheric carbon dioxide in
the atmosphere has been increasing because the
rate of input is larger than the rate of output
from the atmosphere.
10
Recommendations Global Aerosol Watch with GAIN
We recommend the establishment of an
internet-based global aerosol watch system, where
a few experienced observers distributed all over
the world would monitor the daily aerosol pattern
for interesting dust, smoke, or haze aerosol
events. They would utilize the publicly
available on-line satellite, surface monitoring,
and meteorological modeling data provided by many
countries. When an interesting event would occur,
the relevant science and management communities
would be alerted through a Global Aerosol
Information Network (GAIN). Given the alert the
communities could initiate more intense
monitoring and/or prepare the public for the
developing risks. The GAIN system would also be
used for communication and sharing of
internet-based information resources.
Biomass burning - biogeochemists
Aeolian dust - geologists
GAIN Global Aerosol Information Network
Vulcanologists
Radiative effects-Climate Change
Pollution monitoring- Control
Health effects