V11

Question 1

Environmental controls of photosynthesis:

Answer 1

Question 2

NPP and meteorological parameters:

Answer 2

Question 3

Models:

Answer 3

Question 4

Models:

Answer 4

Question 5

Climate–Vegetation Dynamics:

Answer 5

Question 6

Research project:

Regional carbon budgets:

CO 2 sources and sinks

Answer 6

Question 7

Regional anthropogenic source contributions of CO 2 in winter:

Answer 7

Question 8

Further steps:

Answer 8

• 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

Question 9

Matter fluxes:

Volatile organic compounds (VOCs)

Answer 9

• 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

Question 10

Why biogenic hydrocarbons (BVOC)?

Answer 10

Question 11

Why biogenic hydrocarbons (BVOC)?

Answer 11

Question 12

Why biogenic hydrocarbons (BVOC)?

Answer 12

Question 13

Why biogenic hydrocarbons (BVOC)?

Answer 13

Question 14

State-of-the-Art:

Answer 14

• 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

Question 15

Study areas:

Answer 15

• Rural stations (Alpine foothills / Alps):
  
  • Meteorological observatory Hohenpeißenberg (MOHp)
  • Environmental research station Schneefernerhaus (UFS)
  • Garmisch-Partenkirchen - Kramer - Kreuzeck (GAP)
• Urban stations:
  
  • Houston, TX, USA

Question 16

Objectives:

Answer 16

• Identification and quantification of biogenic contributions
  
  • in comparison to anthropogenic contributions
    
    • Potential for ozone formation
• 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

Question 17

Method:

Receptor Modeling with Positive Matrix Factorization

Answer 17

• extended factor analysis
• Non-negativity, weighting of individual data points with uncertainty

Question 18

Determination of source profiles:

Answer 18

• each factor corresponds to one source
• contribution of each source to each individual sample
• typical “fingerprint”:
  
  • chemical composition of each source

Question 19

Source contributions of urban vegetation from the PMF:

Answer 19

Question 20

Source contributions of vegetation from receptor modeling (PMF):

Answer 20

Question 21

Saisonale Variabilität:

Answer 21

Question 22

Daily biogenic contribution:

Answer 22

• 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

Question 23

Research project:

Carbon turnover at plant level

Answer 23

• 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

Question 24

Photosynthesis, transpiration, and BVOC emissions:

parameterization

Answer 24

Question 25

Chemospecies – tree individuals:

Answer 25

• Further steps:
  
  • coupling to atmospheric chemistry (SOA formation)
  • parameterization of biogeochemical models
  • investigation of scaling effects