Thomas Foken, Mathias Göckede, Matthias Mauder University of Bayreuth, Germany Department of Micrometeorology 3 nd CarboEurope-IP Integrated Project Meeting Levi, Finland November, 2005 Thomas Foken, Mathias Göckede, Matthias Mauder Department of Micrometeorology University of Bayreuth, Germany with contributions by Tiina Markkanen University of Helsinki Results of footprint based quality assessment and quality control study for forest sites

Thomas Foken, Mathias Göckede, Matthias Mauder University of Bayreuth, Germany Department of Micrometeorology 3 nd CarboEurope-IP Integrated Project Meeting Levi, Finland November, 2005 Combination of QA/QC tools for eddy covariance measurements with footprint analyses - Quality assessment: Assignment of QC- flags for individual flux measurements according to Foken & Wichura (1996) and Foken et al. (2004) - Footprint-Analysis: Calculation of source areas (model by Rannik et al., 2003) to determine the spatial context of a measurement QA/QC: Evaluation of measurement sites - Concept -

Thomas Foken, Mathias Göckede, Matthias Mauder University of Bayreuth, Germany Department of Micrometeorology 3 nd CarboEurope-IP Integrated Project Meeting Levi, Finland November, Link between data quality and the characteristics of the surrounding terrain - Determination of a footprint climatology for a longer measurement period - Analysis of the flux contributions emitted from different types of land use to the total flux measured - Special effects, like influences of the sensor on the measurements QA/QC: Evaluation of measurement sites - Objectives -

Thomas Foken, Mathias Göckede, Matthias Mauder University of Bayreuth, Germany Department of Micrometeorology 3 nd CarboEurope-IP Integrated Project Meeting Levi, Finland November, 2005 QA/QC: Evaluation of measurement sites - Working programme - Sites with measurements above high vegetation - 23 sites were analyzed and 2 associated sites - no information available from 5 sites (FR-Fon, SE- Nor, SE-Sky1, SE-Sky2, UK-PLa3) Sites with measurements above low vegetation - no analysis of meteorological measurements - fetch analysis, flux contribution from target land use - not reported in this paper

Thomas Foken, Mathias Göckede, Matthias Mauder University of Bayreuth, Germany Department of Micrometeorology 3 nd CarboEurope-IP Integrated Project Meeting Levi, Finland November, 2005 FI-Sod Data quality of latent heat flux Influences of the sensor set up METEK USA-1; Use of the head correction Fr-Pue vertical wind velocity after planar-fit

Thomas Foken, Mathias Göckede, Matthias Mauder University of Bayreuth, Germany Department of Micrometeorology 3 nd CarboEurope-IP Integrated Project Meeting Levi, Finland November, 2005 DE-Wet Boom on the tower, data quality of momentum flux Influences of the sensor set up Mounting of the sonic anemometer on the tower Similar results for NL-Loo

Thomas Foken, Mathias Göckede, Matthias Mauder University of Bayreuth, Germany Department of Micrometeorology 3 nd CarboEurope-IP Integrated Project Meeting Levi, Finland November, 2005 Footprint analysis of fluxes emitted from the target area ● Source-area analysis Basic idea: In complex terrain, the changing source-area under different meteorological conditions affects the flux data quality according to several aspects. Use of the footprint analyses by Rannik et al. (2003): Chose a threshold of 80% of flux emitted by the target land cover: 90% or more of data exceed 80%-threshold: 13 sites 60% to 90% of data exceed 80% threshold: 4 sites 50% to 60% of data exceed the 80% threshold: 3 sites Less than 50% of data exceed the 80% threshold: 4 sites Chose a threshold of 80% of flux emitted by the target land cover: 90% or more of data exceed 80%-threshold: 13 sites 60% to 90% of data exceed 80% threshold: 4 sites 50% to 60% of data exceed the 80% threshold: 3 sites Less than 50% of data exceed the 80% threshold: 4 sites Chose a threshold of 80% of flux emitted by the target land cover 1. 90% or more of data exceed 80%-threshold: 13 sites 2. 60% to 90% of data exceed 80% threshold: 4 sites 3. 50% to 60% of data exceed the 80% threshold: 3 sites 4. Less than 50% of data exceed the 80% threshold: 4 sites

Thomas Foken, Mathias Göckede, Matthias Mauder University of Bayreuth, Germany Department of Micrometeorology 3 nd CarboEurope-IP Integrated Project Meeting Levi, Finland November, 2005 DK-Sor Category 4: Fr-Pue, BE-Bra, DK-Sor, PT-Mit1

Thomas Foken, Mathias Göckede, Matthias Mauder University of Bayreuth, Germany Department of Micrometeorology 3 nd CarboEurope-IP Integrated Project Meeting Levi, Finland November, 2005 PT-Mit1 Category 4: Fr-Pue, BE-Bra, DK-Sor, PT-Mit1

Thomas Foken, Mathias Göckede, Matthias Mauder University of Bayreuth, Germany Department of Micrometeorology 3 nd CarboEurope-IP Integrated Project Meeting Levi, Finland November, 2005 Flux data quality assessment ● Source-area analysis Basic idea: In complex terrain, the changing source-area under different meteorological conditions affects the flux data quality according to several aspects. Use of the footprint analyses by Rannik et al. (2003): Chose a threshold of 80% of flux emitted by the target land cover: 90% or more of data exceed 80%-threshold: 13 sites 60% to 90% of data exceed 80% threshold: 4 sites 50% to 60% of data exceed the 80% threshold: 3 sites Less than 50% of data exceed the 80% threshold: 4 sites Chose a threshold of 80% of flux emitted by the target land cover: 90% or more of data exceed 80%-threshold: 13 sites 60% to 90% of data exceed 80% threshold: 4 sites 50% to 60% of data exceed the 80% threshold: 3 sites Less than 50% of data exceed the 80% threshold: 4 sites

Thomas Foken, Mathias Göckede, Matthias Mauder University of Bayreuth, Germany Department of Micrometeorology 3 nd CarboEurope-IP Integrated Project Meeting Levi, Finland November, 2005 Flux data quality assessment ● Source-area analysis Basic idea: In complex terrain, the changing source-area under different meteorological conditions affects the flux data quality according to several aspects. Use of the footprint analyses by Rannik et al. (2003): Chose a threshold of 80% of flux emitted by the target land cover: 90% or more of data exceed 80%-threshold: 13 sites 60% to 90% of data exceed 80% threshold: 4 sites 50% to 60% of data exceed the 80% threshold: 3 sites Less than 50% of data exceed the 80% threshold: 4 sites Chose a threshold of 80% of flux emitted by the target land cover: 90% or more of data exceed 80%-threshold: 13 sites 60% to 90% of data exceed 80% threshold: 4 sites 50% to 60% of data exceed the 80% threshold: 3 sites Less than 50% of data exceed the 80% threshold: 4 sites 1. Highest quality – no disturbances: 6 sites 2. Only disturbances in isolated wind sectors: 7 sites 3. Isolated disturbances and up to one omnidirectional effect: 7 sites 4. Multiple omnidirectional effects: 5 sites

Thomas Foken, Mathias Göckede, Matthias Mauder University of Bayreuth, Germany Department of Micrometeorology 3 nd CarboEurope-IP Integrated Project Meeting Levi, Finland November, 2005 ● Source-area analysis Basic idea: In complex terrain, the changing source-area under different meteorological conditions affects the flux data quality according to several aspects. Use of the footprint analyses by Rannik et al. (2003): Chose a threshold of 80% of flux emitted by the target land cover: 90% or more of data exceed 80%-threshold: 13 sites 60% to 90% of data exceed 80% threshold: 4 sites 50% to 60% of data exceed the 80% threshold: 3 sites Less than 50% of data exceed the 80% threshold: 4 sites Chose a threshold of 80% of flux emitted by the target land cover: 90% or more of data exceed 80%-threshold: 13 sites 60% to 90% of data exceed 80% threshold: 4 sites 50% to 60% of data exceed the 80% threshold: 3 sites Less than 50% of data exceed the 80% threshold: 4 sites Category 4: CH-Lae, ES-LMa, FI-Hyy, Fr-Pue, It-Col FI-Hyy: CO 2 -flux

Thomas Foken, Mathias Göckede, Matthias Mauder University of Bayreuth, Germany Department of Micrometeorology 3 nd CarboEurope-IP Integrated Project Meeting Levi, Finland November, 2005 Most of the stations: Slightly worse quality during unstable stratification coursed by convection and coherent structures DE-Wei: momentum-flux

Thomas Foken, Mathias Göckede, Matthias Mauder University of Bayreuth, Germany Department of Micrometeorology 3 nd CarboEurope-IP Integrated Project Meeting Levi, Finland November, 2005 Overview (all stations) ● Source-area analysis Basic idea: In complex terrain, the changing source-area under different meteorological conditions affects the flux data quality according to several aspects. Use of the footprint analyses by Rannik et al. (2003): Chose a threshold of 80% of flux emitted by the target land cover: 90% or more of data exceed 80%-threshold: 13 sites 60% to 90% of data exceed 80% threshold: 4 sites 50% to 60% of data exceed the 80% threshold: 3 sites Less than 50% of data exceed the 80% threshold: 4 sites Chose a threshold of 80% of flux emitted by the target land cover: 90% or more of data exceed 80%-threshold: 13 sites 60% to 90% of data exceed 80% threshold: 4 sites 50% to 60% of data exceed the 80% threshold: 3 sites Less than 50% of data exceed the 80% threshold: 4 sites

Thomas Foken, Mathias Göckede, Matthias Mauder University of Bayreuth, Germany Department of Micrometeorology 3 nd CarboEurope-IP Integrated Project Meeting Levi, Finland November, 2005 Overview (all stations) ● Source-area analysis Basic idea: In complex terrain, the changing source-area under different meteorological conditions affects the flux data quality according to several aspects. Use of the footprint analyses by Rannik et al. (2003): Chose a threshold of 80% of flux emitted by the target land cover: 90% or more of data exceed 80%-threshold: 13 sites 60% to 90% of data exceed 80% threshold: 4 sites 50% to 60% of data exceed the 80% threshold: 3 sites Less than 50% of data exceed the 80% threshold: 4 sites Chose a threshold of 80% of flux emitted by the target land cover: 90% or more of data exceed 80%-threshold: 13 sites 60% to 90% of data exceed 80% threshold: 4 sites 50% to 60% of data exceed the 80% threshold: 3 sites Less than 50% of data exceed the 80% threshold: 4 sites

Thomas Foken, Mathias Göckede, Matthias Mauder University of Bayreuth, Germany Department of Micrometeorology 3 nd CarboEurope-IP Integrated Project Meeting Levi, Finland November, 2005 Conclusions ● Source-area analysis Basic idea: In complex terrain, the changing source-area under different meteorological conditions affects the flux data quality according to several aspects. Use of the footprint analyses by Rannik et al. (2003): Chose a threshold of 80% of flux emitted by the target land cover: 90% or more of data exceed 80%-threshold: 13 sites 60% to 90% of data exceed 80% threshold: 4 sites 50% to 60% of data exceed the 80% threshold: 3 sites Less than 50% of data exceed the 80% threshold: 4 sites Chose a threshold of 80% of flux emitted by the target land cover: 90% or more of data exceed 80%-threshold: 13 sites 60% to 90% of data exceed 80% threshold: 4 sites 50% to 60% of data exceed the 80% threshold: 3 sites Less than 50% of data exceed the 80% threshold: 4 sites The footprint and data quality analysis can only be one criteria for site evaluation. Is the ecosystem or the latitude or altitude of the station important for the aims of CARBOEUROPE ? Is the special character of an ecosystem (boreal, alpine) a reason for a lower data quality ? Is the station equipped also with other measuring systems that this station can be used for further research ? Is the staff of the station able to handle even complicate situations and make footprint and data quality analysis before submitting the data to the data basis ?