Atmospheric mixing and pollution transport 


ANSTO's atmospheric radioactivity science program contributes to international efforts aimed at improving our understanding of mixing and transport processes in the earth’s atmosphere, with a strong focus on the sources and fate of airborne pollutants and greenhouse gases.
 
AMPT_p1AMPT_p2AMPT_p3

 

Radon in the atmosphere

 

1500 L dual flow loop, two filter radon detector
ANSTO-built 1500 L dual flow loop, two filter radon detector
 
Radon sample extraction rig at ANSTO
Radon sample extraction rig at ANSTO
Pollution and greenhouse gases emitted into the atmosphere from the Earth's surface can remain close to the ground, potentially causing health problems for the local population, or they can be mixed upwards into the lower part of the atmosphere where they can be transported across regions, countries and continents.
 
Requirements for atmospheric composition and air quality monitoring are becoming ever more demanding with respect to precision and geographical coverage, not just for scientific process studies, but also for national and international inventory and accounting purposes.
 
At the same time, the success of forecasts produced by pollution, weather and climate models, such as those run routinely by the Bureau of Meteorology and the CSIRO, is critically dependent upon the accuracy with which mixing and transport processes in the lower atmosphere are represented.
 
ANSTO’s Atmospheric Mixing and Pollution Transport (AMPT) group conducts experimental research using 222Rn (radon), a naturally-occurring radioactive trace gas of terrestrial origin.
 
AMPT develops unique instrumentation systems for surface, tower and aircraft based platforms, supported by specialised laboratory sample processing and analysis facilities, and deploys them in collaborative long-term and campaign-style measurement programs as part of national and international efforts to advance scientific knowledge of the earth’s atmosphere and pollution transport.
 
Outcomes from this research are aimed at enabling practical, science-based improvements to the management of pollution (health) and alleviation of the effects of climate change.
 
AMPT is also engaged in contractual work, building ANSTO radon detectors and analysing gas, liquid and solid samples for research collaborators as well as for government and commercial clients.
 
See also: Radon Analytical Laboratory.

Global and regional atmospheric composition

 
ANSTO’s unique technology for highly sensitive measurements of atmospheric radon is recognised by the World Meteorological Organisation (WMO) as the best in the world for global and regional atmospheric composition baseline studies.
IER_Cape_Grim
The Cape Grim baseline Air Pollution Station in Northwest Tasmania
 
AMPT_GAWsite
WMO-GAW site at the Korean King Sejong Station in Antarctica
 AMPT_MarineNational
Marine National Facility RV Investigator
 
As an unambiguous tracer of terrestrial influence on air mass composition, radon is an essential component of baseline studies for: selection of least terrestrially perturbed marine air masses; tracing and analysis of air mass history and fetch; calibration / constraint of regionally-integrated emission estimates for important distributed trace gases; and evaluation of transport and mixing schemes in climate and chemical transport models.
 
AMPT leads the radon component of the Cape Grim Baseline Air Pollution Station Science Program. Cape Grim Station is operated by the Bureau of Meteorology (BoM) as a principal node of the WMO Global Atmospheric Watch program (WMO-GAW).
 
AMPT also leads or contributes to radon monitoring programs at other key WMO-GAW stations worldwide, including Mauna Loa Observatory in Hawaii, Cape Point Observatory in South Africa, Gosan Island in South Korea, Jungfraujoch in the Swiss Alps, King Sejong Station in Antarctica and Mt Waliguan in Tibet.
 
The network of AMPT radon measurements at Cape Grim, Macquarie Island, Cape Point, King Sejong Station and aboard the Australian National Marine Facility RV Investigator is collectively referred to as ANSTO’s “Southern Ocean Air Composition Tracer Network”.
 
This network represents a unique tracer facility for aiding the characterisation of sources and movement of atmospheric pollutants in the Southern Ocean region.
 

Atmospheric mixing and surface exchange

AMPT_aircraft
Radon measurements from aircraft

 

ANSTO builds and deploys tower-based and airborne instruments to measure vertical radon variations through the lower atmosphere.
 
The AMPT group takes continuous two-point radon gradient measurements from towers in Sydney Australia and Cabauw in The Netherlands, and also collects detailed radon profiles in the lower troposphere (up to 3-4km) using samplers mounted on motor-gliders. 
 
This research contributes to a richer, quantitative understanding of mixing and exchange processes for heat, momentum, water vapour, trace gases and pollution in the lower atmosphere on a range of scales, thereby providing valuable observational underpinning to improved representations of physical processes in weather, climate and chemical transport models.
 

Air pollution and trace gases

 
This research capitalises on the global need for improved characterisation of sources and transport of atmospheric pollutants.
AMPT_RD_wide
Fine particle pollution concentrations in Sydney, nights with different radon-based stability categories: near neutral (black squares); weakly stable (red circles); moderately stable (green triangles); very stable (blue triangles)
 
AMPT researchers have developed a novel technique that uses near-surface radon measurements to quantify the degree of pollutant mixing more accurately than is possible using common meteorological methods. 
By applying radon-based mixing categories to simultaneous measurements of urban pollutants, it is possible to clearly characterise nocturnal pollution concentrations typical of “well-mixed” to “stable” atmospheric conditions, even under very low wind speeds.
 
This information is crucial for the estimation of public exposure to harmful pollutants. The new radon-based technique has been successfully applied in urban pollution studies in Sydney, Australia, and Lanzhou, China.
 
ANSTO operates a network of radon monitoring stations in the greater Sydney area, co-located with fine particle pollution sampling units. By combining information on the recent history of the airstream (provided by the radon measurements) with elemental analysis of the pollution samples using Ion Beam Analysis (provided by ANSTO's ANTARES accelerator), seasonal to inter-annual patterns of pollution and greenhouse gas emissions can be characterised for urban and industrial sources impacting a high proportion of the Australian population.
 
ANSTO has a major involvement in international carbon research programs. Data from AMPT’s global network of high precision radon detectors, deployed at surface sites and on tall towers, is used for pollution characterisation studies and calibration of regional greenhouse gas emission estimates in Australia and Europe. Radon is the best natural tracer for this purpose, and high quality radon measurements are crucial to these research programs.
  
 

Key collaborations

 
AMPT has strong national links to the Australian Bureau of Meteorology (BoM) and the CSIRO. International collaborations include involvement in the WMO Global Atmosphere Watch and European carbon programs.
 
Baseline and atmospheric composition: BoM; CSIRO Ocean and Atmosphere Flagship (CO&A); NOAA-CMDL; South African Weather Service (SAWS); Korean Polar Research Institute (KOPRI); Jeju National University (South Korea); University of Basel (Switzerland); China Meteorological Authority (CMA); University of Melbourne (UniMelb).
 
European Carbon Program: Energy Research Centre of the Netherlands (ECN); University of Basel (Switzerland); University of Groningen (Netherlands); CNRS (France); EU Joint Research Centre at Ispra (Italy); University of Heidelberg (Germany).
 
Vertical mixing and surface exchange: ECN; Airborne Research Australia (Flinders University); Centre for Australian Weather and Climate Research (CAWCR).
 
Atmospheric pollution: Jeju and Hanyang Universities (South Korea); University of Basel (Switzerland); CMA; CAWCR; CO&A; University of Wollongong (UoW); UniMelb; NSW Office of Environment and Heritage.
 
Southern Ocean and Antarctica: Australian Antarctic Division (AAD); KOPRI; Australian Marine National Research Facility (CSIRO).
 

Contacts

 
Dr Alastair Williams, PhD, FRMetS
Leader, Atmospheric Research Group
Phone: +61-2-9717 3694
Email: Alastair.Williams@ansto.gov.au