Regional Climate and Biosphere-Atmosphere Interactions
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Regional climate models use a dynamical downscaling technique to simulate the impact of global climate at finer resolutions. Typically, the grid-cell resolution of a regional climate model ranges from 20-60 km, wheras the grid-cell resolution for a global model is ~300-500 km. These high resolution studies are better able to capture complex topographic features and land surface resposes to climate change, and can assess smaller-scale, regional climate signatls that may not be simulated in global models.
The tool our group uses for this type of analysis is the ICTP Regional Climate Model. This model, originally developed at NCAR and now supported by the ICTP, is based on the MM5 dynamical core and adds detailed radiation, cloud, and land surface schemes to allow the model to be run for extended time periods.
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Because the land surface component represents the lower boundary condition of the atmospheric models, changes in the land surface and its representation in atmospheric models can have significant effects on regional and global climate. The effects of the biosphere on the atmosphere are modeled through these land surface models. Our research group has coupled a recently developed, state-of-the-science land surface model, The Community Land Model (CLM version 3.5) to the RegCM in order to improve the representation of the land surface. This newly coupled model will be part of the next RegCM release (Spring 2010), but please contact us if you are interested in obtaining a beta version.
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Related Projects:
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Chemistry-Climate Feedbacks on Egypt and the Nile River Basin, PIs: Allison Steiner (US) and Ashraf Zakey (Egypt), US Collaborators: Sanford Sillman (UM) and Rahul Zaveri (PNNL), Funding Source: US-Egypt Joint Science and Technology Fund
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Integration of physical and social sciences for development of a sustainable water resouce policy in Bolivia, South America PI: Christopher Poulsen (UM-Geological Sciences) co-Is: Todd Ehlers (UM-Geological Sciences), Maria Carmen Lemos (UM-SNRE), Allison Steiner (UM-AOSS) Funding Source: UM Graham Environmental Sustainability Institute
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Recent Papers:
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Steiner, A. L., J.S. Pal, S.A. Rauscher, J.L. Bell, N.S. Diffenbaugh,A. Boone, L.C. Sloan and F. Giorgi (2009) Land surface coupling in regional climate simulationsof the West African monsoon, Climate Dynamics, doi: 10.1007/s00382-009-0543-6, available online
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Giorgi, F., N.S. Diffenbaugh, X.J. Gao, E. Coppola, S.K. Dash, O. Frumento, S.A. Rauscher, A. Remedio, I. Seidou Sanda, A. Steiner, B. Sylla and A.S. Zakey (2008) The Regional Climate Change Hyper-Matrix Framework, Eos, 89 (45), 445-446.
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Regional Atmospheric Chemistry and Biosphere-Atmosphere Interactions
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Chemistry is the troposphere is affected by both anthropogenic emissions and natural emissions from the biosphere. My past work has used regional atmospheric chemistry models to evaluate the contribution of emissions from the biosphere and to understand their impact on regional chemistry.
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One way that the biosphere can affect tropospheric composition is through the emission of biogenic volatile organic compounds (VOC). Biogenic VOCs are a broad range of carbon-containing compounds that are emitted naturally from vegetation. Typically, atmospheric variables such as light and temperature control their emissions, indicating their close link to climate. Biogenic VOCs are important for gas-phase atmospheric chemistry because they can react with NOx in the presence of sunlight to form ground-level ozone. Once they are oxidized in the atmosphere, they can also impact the particle concentrations in the atmosphere, by forming secondary organic aerosol (SOA). Both of these processes can affect air quality and climate.
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Our group is working on developing a regional-scale coupled chemistry-climate model that can account for these natural emissions to the atmosphere on long-term (e.g., decadal) scales.
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Aerosols, which are solid or liquid particles suspended in the atmosphere, have a significant effect on climate. These particles can be emitted naturally (e.g., dust, volcanic emissions) or anthropogenically (e.g., industrial and motor vehicle emissions). In addition, many gas phase organic species partition to the particle phase once in the atmosphere, further adding to atmospheric aerosol concentrations. There are many facets of atmospheric aerosol research, including understanding the chemical composition, size distribution, and optical properties of these particles. To date, my work has focused on modeling anthropogenic aerosols and understanding how they affect the climate at the Earth's surface.
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In addition to the regional scale, our group is also looking at the interactions between atmospheric chemistry and climate at the canopy scale. We are working to develop a coupled chemistry-climate model for use in evaluating measurments during the 2009 CABINEX study at the University of Michigan Biological Station. Updates to come soon!
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Related Projects:
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Chemistry-Climate Feedbacks on Egypt and the Nile River Basin, PIs: Allison Steiner (US) and Ashraf Zakey (Egypt), US Collaborators: Sanford Sillman (UM) and Rahul Zaveri (PNNL), Funding Source: US-Egypt Joint Science and Technology Fund
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Collaborative Research: PROPHET 2009: Community Atmosphere-Biosphere Interactions Experiment (CABINEX) PI: Mary Anne Carroll (UM-AOSS) co-Is: Allison Steiner (UM-AOSS) Funding Source: NSF Atmospheric Chemistry
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Recent Papers:
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Steiner, A. L., R.C. Cohen, R.A. Harley, S. Tonse, D.B. Millet, G.W. Schade and A.H. Goldstein (2008) VOC reactivity in central California: Comparing an air quality model to ground-based measurements, Atmos. Chem. Phys., 8, 351-368.
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Steiner, Allison L., S. Tonse, R.C. Cohen, A.H. Goldstein, and R.A. Harley (2006) The influence of future climate and emissions on regional air quality in California, JGR-Atmospheres, 111, D18303, doi: 10.1029/2005JD006935.
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Primary Research Qustions
How does this all fit together? We're interested in understanding the
feedbacks between the atmosphere and biosphere for both chemistry
and climate. This includes the following questions:
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How will changes in the land surface impact regional climate, and how do the spatial scales of model represtations ofthe land surface affect climate?
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What are the climatic controls on biogenic VOC emissions, and how do these affect tropospheric chemistry on the interannual time scales?
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How do short-lived species such as tropospheric ozone and atmospheric aerosols affect regional climate?
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What will be the impacts of changing biogenic and anthropogenic emissions on regional climate?