Environmental controls of photosynthesis:
NPP and meteorological parameters:
Models:
Models:
Climate–Vegetation Dynamics:
Research project:
Regional carbon budgets:
CO 2 sources and sinks
Regional anthropogenic source contributions of CO 2 in winter:
Further steps:
- Coupling with:
- VPRM - Vegetation Photosynthesis and Respiration Model (Mahadevan et al. 2008)
- STILT - Stochastic Time-Inverted Lagrangian Transport Model (Lin et al. 2003)
- Methods for filtering anthropogenic sources (Tuzson et al. 2010)
- Flux sites, satellite-linked measurements
Matter fluxes:
Volatile organic compounds (VOCs)
- anthropogenic:
- from combustion, solvents, leakages, petrochemistry,…
- alkanes, alkenes, alkynes, aromatics
- oxygenated VOC
- biogenic (BVOC):
- from current synthesis and storage pools
- > 1000 different substances (known)
- isoprene
- terpenes
- oxygenated VOC
Why biogenic hydrocarbons (BVOC)?
Why biogenic hydrocarbons (BVOC)?
Why biogenic hydrocarbons (BVOC)?
Why biogenic hydrocarbons (BVOC)?
State-of-the-Art:
- BVOC emissions dependent on temperature and radiation
- dependent on type of ecosystem, stage of development, extent of biotic and abiotic stresses
- few experimental studies on interactions of stress with emissions, few tree species/ecosystems studied
- influence of stress (e.g. temperature, drought, pests, salt) very inconsistent
- hardly represented in models or represented with large uncertainties but very important for process understanding of atmospheric chemistry
Study areas:
- Rural stations (Alpine foothills / Alps):
- Meteorological observatory Hohenpeißenberg (MOHp)
- Environmental research station Schneefernerhaus (UFS)
- Garmisch-Partenkirchen - Kramer - Kreuzeck (GAP)
- Urban stations:
- Houston, TX, USA
Objectives:
- Identification and quantification of biogenic contributions
- in comparison to anthropogenic contributions
- Potential for ozone formation
- in comparison to anthropogenic contributions
- Identification of source regions
- Seasonal variability of VOC sources
- Differentiation of air masses from the free troposphere and the planetary boundary layer
- Influences of meteorology and photochemistry
- Applicability of the PMF receptor model in rural areas
Method:
Receptor Modeling with Positive Matrix Factorization
- extended factor analysis
- Non-negativity, weighting of individual data points with uncertainty
Determination of source profiles:
- each factor corresponds to one source
- contribution of each source to each individual sample
- typical “fingerprint”:
- chemical composition of each source
Source contributions of urban vegetation from the PMF:
Source contributions of vegetation from receptor modeling (PMF):
Saisonale Variabilität:
Daily biogenic contribution:
- significant importance of biogenic emissions in both rural and urban atmosphere
- thus direct influence on air quality (regional) and climate system (global)
How will climate change and (urban) stress affect biogenic emissions in the future?
- Sustainable protection of ecosystem services and environmental quality
Research project:
Carbon turnover at plant level
- Influence of drought stress and recovery on young pine trees of different provenance (Spain, Italy, Germany)
- Gas exchange measurements (+ physiological parameters)
- C-emissions (biogenic hydrocarbons)
- Photosynthesis
- Transpiration
- Process understanding:
- isotope labeling
Photosynthesis, transpiration, and BVOC emissions:
parameterization
