Carbon-Nitrogen Interactions Breakout Group

Flocke/Guenther: What is the impact of changes in vegetation, including the dead trees on CO2 uptake biogenic emissions, and the water cycle?

The carbon uptake and associated VOC emissions of the western landscape is decreasing. Why? Due to changes in land cover, ecological disturbances, inc invasive

species, insect outbreaks, and climate, inc. water availability?

Tower and Airborne flux measurement capabilities: CO2, water vapor, heat, energy, VOCs, reactive N, O3, soil moisture, comprehensive meteorology

Karl: What is the impact of human induced land use changes on C cycle and trace gas emissions , especially the impact of wholesale change to crop growth to support bio-fuels?

The future changes in agricultural practices in the US, due to growing demand on bio-fuel production, that could offset the air quality mitigation strategies through changing

VOC emissions and increased reactive N emissions.

Measurements: VOCs, O3, NOx, NOy, met measurements and VOC fluxes on switchgrass and poplar plantations throughout the US.

Carbon/Nitrogen continued

Mak: What is the importance of the tropical coastal zone and the immediate turnover in that zone for the C cycle and their dependence on N import, N deposition, and riverine inputs?

The contribution of carbon dioxide for the export of terrestrial organic carbon in tropical coastal zones is much larger than what is represented in current carbon cycle models.

Measurements: CO2 fluxes and 13 CO2, and 14CO2 wet and dry intensives, 2-3 times per year/ coastal/tidal platforms.

Cohn: Can we improve CO2 inversions using height resolved CO2 measurements? Can we get info that is better than what Britt used to improved models and inversions?

CO2 inversions can be improved by better representation of boundary layer dynamics and atmospheric chemistry.

Measurements: O3, NOx, NOy, CO, VOCs globally and vertically resolved

Melville/Huebert: ocean surface processes and air-sea gas fluxes

Predictions of air-sea gas fluxes can be improved by including the effects of surface wave processes, surfactants, bubbles.

Measurements: boundary layer measurement of air-sea fluxes coherent with surface wave measurements.

Fried/Cantrell/Guenther: Can we close the carbon budget for a specific locations including CO2, reactive C including CO, VOCs, and aerosols?

Focus short-lived intermediates, especially C, N and HOx cycle

Total carbon budgets cannot be closed because a

a significant fraction of the oxidation products of isoprene have not been accounted for. What fraction of the isoprene emitted is deposited before

being oxidized to CO2?

Measurements: redo Blodgett study with multi-phase measurements of free radicals, radiation, water, isoprene oxidation products, HOx, NOx,

NOy PAN above a poplar plantation.

Carbon/Nitrogen continued

Lemone/Melville: How does extreme weather, i.e. hurricanes, frontal passages, storm squalll lines impact the exchange of trace gases on land and oceans? What

happens when cold water comes to the surface after a big stir-up following hurricane passage.

Transport, uptake and emissions may increase disproportionately during and after extreme weather events and require quantification.

Measurements: Chasing fluxes in adverse environments, UAVs, drones, deployable buoys, esp. after hurricanes or towers, instrumented drilling platforms, flying above

systems

Huebert: Do we sufficiently understand the bias introduced by fair weather sampling instead?

Need to pay special attention to the neglected areas of the globe and neglected seasons.

Holland: What role do nitric and sulfuric acid and ammonia inputs from the atmosphere play in ocean acidification?

Nitric and sulfuric acid, and ammonia inputs from the atmosphere contribute to ocean acidification and future CO2 uptake.

Measurements: wet and dry deposition of NOx, SOx, and HNO3 on deployable buoys

Within canopy exchange and turbulent exchange of CO2 and trace gases.

Oncley: What is the role of horizontal advection in calculating NEE locally? Horizontal advection is large enough to change the apparent sign of Net Ecosystem

CO2 Exchange for a typical forest ecosystem. Measurements: 3-D mapping of CO2 concentrations within a box. Tram CO2

system. CO2 fluxes along sides and top of box

Sun: Understand trace gas transport in complex terrain, including nighttime and daytime transport. Need to understand canopy-atmosphere exchange, including vertical and horizontal exchange and their scalability.

Lenschow: How does turbulent boundary layer affect fluxes and distributions of trace gas reactive species on the time scale of a few seconds to few hours?

Patton: Is the frequency, intensity, and/or coherence of canopy-scalestructures affected by the radiative coupling between spatiallyheterogeneous boundary-layer clouds and underlying vegetation? Doescloud/land-surface coupling impact the intermittent venting ofbiogenic and/or surface sourced species? Are the species trapped fora longer/shorter time in the sub-canopy layers which would modify thewithin-canopy chemical processing?

For the Record• Hakkarinen: Stabilize emissions of CO2 in round numbers, at what

concentration in the atmosphere would the concentration stabilize? How do we get to 550-580 ppm?

• Yes, we predict the observed mass of CO2 in the atmosphere up to today. Can we forecast what the observed mass of carbon dioxide is 20 years from now to within 5%?

• Mayer: what can Lidars do for you? Can flourescent lidars tell you something you want to know? Column content okay? Range resolved measurement? What temporal and spatial resolution is needed?

• Holland: Can we do complete C and N budgets, focusing on their interactions? Can both budgets be balanced?

• Is ozone important for the CO2 budgets and what is the effect of N fertilization on CO2?

• Cantrell: What is the future release of methane hydrates?• Fried: Does nitrification impact OCS emissions and emissions of other trace

gases?