Details of Award
NERC Reference : NE/J004723/1
Quantifying the impact of atmospheric aerosol on diffuse radiation and the Amazon biosphere
Grant Award
- Principal Investigator:
- Dr D Spracklen, University of Leeds, School of Earth and Environment
- Grant held at:
- University of Leeds, School of Earth and Environment
- Science Area:
- Atmospheric
- Earth
- Freshwater
- Marine
- Terrestrial
- Overall Classification:
- Atmospheric
- ENRIs:
- Biodiversity
- Environmental Risks and Hazards
- Global Change
- Natural Resource Management
- Pollution and Waste
- Science Topics:
- Land - Atmosphere Interactions
- Radiative Processes & Effects
- Tropospheric Processes
- Climate & Climate Change
- Abstract:
- Trees in the Amazon are getting bigger absorbing large amounts of carbon dioxide from the atmosphere; equivalent to almost 10% of anthropogenic greenhouse gas emissions. This "carbon sink" slows the buildup of atmospheric carbon dioxide and therefore plays an important role in regulating climate change. At the moment we do not understand why the Amazon forest is behaving in this way. One potential reason is changes to the amount of tiny particles in the atmosphere called aerosols. We know that human activity has significantly changed the amount of aerosol over the Amazon: each dry season, humans start forest fires across southern parts of the Amazon basin (the so called "Arc of deforestation"). These fires emit large quantities of smoke aerosol into the atmosphere, scattering and absorbing radiation from the sun. This scattering of the sun's rays decreases the amount of direct radiation reaching the surface but increases the amount of diffuse radiation. It has been known for a long time that increases in diffuse radiation can increase plant productivity. For example, gardeners place "diffuser sheets" inside greenhouses that increase diffuse radiation in the similar way to atmospheric particles. The reason why diffuse radiation increases plant productivity is that it penetrates deeper into the canopy and illuminates leaves that would otherwise be in the shade. These previously shaded leaves can do more photosynthesis. A recent study showed that this effect can be very important, increasing the amount of carbon taken up by forests globally by 25%. It is therefore likely that deforestation fires (a major source of carbon dioxide emissions) are at least partly contributing to the sink of carbon dioxide in undisturbed forests in the Amazon basin. So far this effect has not been carefully studied for forests in the Amazon. Firstly, it is not well known exactly how much the amount of aerosol particles over the Amazon has changed. Second, no one has quantified how this change in aerosol particles has altered the amount of diffuse radiation. And finally we do not know whether these changes in diffuse radiation are sufficient to explain any of the observed changes in forest biomass across the Amazon. In this project we will use a suite of atmospheric aerosol, radiation and land-surface models to explore the problem. We will use a global model of atmospheric aerosol to simulate how aerosol distributions have changed over the Amazon over the last few decades. We will input these changes in aerosol into an atmospheric radiation model to quantify how amounts of diffuse radiation have changed. Finally, we will use these changes in diffuse radiation as input to a land-surface model to quantify how it impacts Amazon forests. At each step in the process we will use observations from ground-sites and satellite sensors to test how well the models explain observed changes. The project will lead to a much better understanding of how Amazon aerosol has changed and how this impacts diffuse radiation and the biosphere.
- NERC Reference:
- NE/J004723/1
- Grant Stage:
- Completed
- Scheme:
- New Investigators (FEC)
- Grant Status:
- Closed
- Programme:
- New Investigators
This grant award has a total value of £79,967
FDAB - Financial Details (Award breakdown by headings)
| DI - Other Costs | Indirect - Indirect Costs | DA - Estate Costs | DI - Staff | DA - Other Directly Allocated | DI - T&S |
|---|---|---|---|---|---|
| £2,480 | £30,146 | £11,652 | £28,692 | £5,017 | £1,980 |
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