{"id":{"repo_id":"heid-thes","oai_identifier":"oai:archiv.ub.uni-heidelberg.de:39077"},"canonical_url":"https://search.dev.ndltd.org/etd/heid-thes/oai:archiv.ub.uni-heidelberg.de:39077","repository":{"repo_id":"heid-thes","name":"Universität Heidelberg ; Thes","base_url":"http://archiv.ub.uni-heidelberg.de/volltextserver/cgi/oai2"},"display":{"title":"Decomposition of Urban CO2 Fluxes into Fossil and Biogenic Components using a novel Relaxed Eddy Accumulation System","abstract":"The aim of this thesis is the characterization of a novel relaxed eddy accumulation (REA) system for collection of 14CO2 air samples and its first application in the city of Zurich, Switzerland. The REA system, developed within the ICOS (Integrated Carbon Observation System) Cities project, selects air based on a 20 Hz vertical wind signal into an upwind and a downwind sample, allowing for the first time 14CO2-based decomposition of CO2 fluxes into fossil and biogenic components. This is prerequisite for independent eddy covariance-based top-down assessment of urban fossil fuel CO2 (ffCO2) emissions. Quality control tests during the Zurich campaign show that there is no significant bias between upwind and downwind sampling and that concentration differences between the flask pairs agree with the differences of in situ measurements within (0.02 +- 0.21) ppm. In total, 300 flask pairs were collected, of which 95 were analyzed for 14CO2. These were grouped and interpreted according to atmospheric sampling conditions. The potential of 14CO2-based CO2 flux separation was demonstrated for samples with ffCO2 differences greater than 1.2 ppm. However, for the majority of the collected samples, evaluating ffCO2 estimates is limited by large uncertainties due to the precision of 14CO2 measurements. Exploiting the full potential of the ICOS REA flask sampling system requires larger signals, which could potentially be achieved by lower sampling heights.","abstract_html":"The aim of this thesis is the characterization of a novel relaxed eddy accumulation (REA) system for collection of 14CO2 air samples and its first application in the city of Zurich, Switzerland. The REA system, developed within the ICOS (Integrated Carbon Observation System) Cities project, selects air based on a 20 Hz vertical wind signal into an upwind and a downwind sample, allowing for the first time 14CO2-based decomposition of CO2 fluxes into fossil and biogenic components. This is prerequisite for independent eddy covariance-based top-down assessment of urban fossil fuel CO2 (ffCO2) emissions. Quality control tests during the Zurich campaign show that there is no significant bias between upwind and downwind sampling and that concentration differences between the flask pairs agree with the differences of in situ measurements within (0.02 +- 0.21) ppm. In total, 300 flask pairs were collected, of which 95 were analyzed for 14CO2. These were grouped and interpreted according to atmospheric sampling conditions. The potential of 14CO2-based CO2 flux separation was demonstrated for samples with ffCO2 differences greater than 1.2 ppm. However, for the majority of the collected samples, evaluating ffCO2 estimates is limited by large uncertainties due to the precision of 14CO2 measurements. Exploiting the full potential of the ICOS REA flask sampling system requires larger signals, which could potentially be achieved by lower sampling heights.","abstract_has_math":false,"creators":["Kunz, Ann-Kristin"],"institution":"Universität Heidelberg","degree_name":null,"degree_level":"master","degree_discipline":null,"degree_department":null,"school":null,"contributors":["Levin, Ingeborg"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2023,"date_issued":"2023-10-02","date_published":"2023-10-02","updated_at":"2026-07-24T02:31:02Z","subjects":[],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://www.ub.uni-heidelberg.de/archiv/39077","outbound_label":"Repository record","outbound_source":"source_url"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Levin, Ingeborg"]},{"key":"dc:creator","label":"Author","values":["Kunz, Ann-Kristin"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:publisher","label":"Institution","values":["Universitätsbibliothek Heidelberg"]},{"key":"dc:type","label":"Dc Type","values":["masterThesis"]},{"key":"thesis:degree_level","label":"Degree Level","values":["master"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Universität Heidelberg"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The aim of this thesis is the characterization of a novel relaxed eddy accumulation (REA) system for collection of 14CO2 air samples and its first application in the city of Zurich, Switzerland. The REA system, developed within the ICOS (Integrated Carbon Observation System) Cities project, selects air based on a 20 Hz vertical wind signal into an upwind and a downwind sample, allowing for the first time 14CO2-based decomposition of CO2 fluxes into fossil and biogenic components. This is prerequisite for independent eddy covariance-based top-down assessment of urban fossil fuel CO2 (ffCO2) emissions. Quality control tests during the Zurich campaign show that there is no significant bias between upwind and downwind sampling and that concentration differences between the flask pairs agree with the differences of in situ measurements within (0.02 +- 0.21) ppm. In total, 300 flask pairs were collected, of which 95 were analyzed for 14CO2. These were grouped and interpreted according to atmospheric sampling conditions. The potential of 14CO2-based CO2 flux separation was demonstrated for samples with ffCO2 differences greater than 1.2 ppm. However, for the majority of the collected samples, evaluating ffCO2 estimates is limited by large uncertainties due to the precision of 14CO2 measurements. Exploiting the full potential of the ICOS REA flask sampling system requires larger signals, which could potentially be achieved by lower sampling heights.","Ziel dieser Arbeit ist die Charakterisierung eines neu entwickelte Relaxed Eddy Accumulation (REA) Systems zur Sammlung von 14CO2 Luftproben und dessen erste Anwendung in der Stadt Zürich, Schweiz. Das im Rahmen des ICOS Cities Projekts entwickelte REA System selektiert Luft auf Grundlage eines 20 Hz Vertikalwindsignals in eine Aufwind- und eine Abwindprobe, welches erstmals eine direkte 14CO2-basierte Zerlegung der CO2-Flüsse in fossile und biogene Anteile ermöglicht. Dies ist Voraussetzung für eine unabhängige Eddy Covarianz-basierte Top-Down-Bestimmung urbaner ffCO2 Emissionen. Qualitätskontrolltests während der Zürich Kampagne zeigen, dass es keine signifikanten Unterschiede zwischen Auf- und Abwindprobennahme gibt und dass die Konzentrationsdifferenzen der Flask-Paare innerhalb von (0.02 +- 0.21) ppm mit den Differenzen der in situ Messungen übereinstimmen. Insgesamt wurden 300 Proben gesammelt, von denen 95 auf 14CO2 analysiert wurden. Diese wurden nach atmosphärischen Bedingungen während der Probenahmezeiträume gruppiert und interpretiert. Das Potenzial der 14CO2-basierten CO2-Fluss Separation konnte für Proben mit ffCO2-Differenzen größer als 1.2 ppm gezeigt werden. Für den Großteil der gesammelten Proben ist die Auswertung der ffCO2-Bestimmungen jedoch durch große Unsicherheiten aufgrund der Präzision der 14CO2-Messungen eingeschränkt. Um das volle Potenzial des ICOS REA Flask-Sammlers auszuschöpfen, sind größere Signale erforderlich, welche durch niedrigere Probenahmehöhen erreicht werden könnten."]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Decomposition of Urban CO2 Fluxes into Fossil and Biogenic Components using a novel Relaxed Eddy Accumulation System"]}]}],"canonical_facts":{"dc:contributor":["Levin, Ingeborg"],"dc:creator":["Kunz, Ann-Kristin"],"dc:description.abstract":["The aim of this thesis is the characterization of a novel relaxed eddy accumulation (REA) system for collection of 14CO2 air samples and its first application in the city of Zurich, Switzerland. The REA system, developed within the ICOS (Integrated Carbon Observation System) Cities project, selects air based on a 20 Hz vertical wind signal into an upwind and a downwind sample, allowing for the first time 14CO2-based decomposition of CO2 fluxes into fossil and biogenic components. This is prerequisite for independent eddy covariance-based top-down assessment of urban fossil fuel CO2 (ffCO2) emissions. Quality control tests during the Zurich campaign show that there is no significant bias between upwind and downwind sampling and that concentration differences between the flask pairs agree with the differences of in situ measurements within (0.02 +- 0.21) ppm. In total, 300 flask pairs were collected, of which 95 were analyzed for 14CO2. These were grouped and interpreted according to atmospheric sampling conditions. The potential of 14CO2-based CO2 flux separation was demonstrated for samples with ffCO2 differences greater than 1.2 ppm. However, for the majority of the collected samples, evaluating ffCO2 estimates is limited by large uncertainties due to the precision of 14CO2 measurements. Exploiting the full potential of the ICOS REA flask sampling system requires larger signals, which could potentially be achieved by lower sampling heights.","Ziel dieser Arbeit ist die Charakterisierung eines neu entwickelte Relaxed Eddy Accumulation (REA) Systems zur Sammlung von 14CO2 Luftproben und dessen erste Anwendung in der Stadt Zürich, Schweiz. Das im Rahmen des ICOS Cities Projekts entwickelte REA System selektiert Luft auf Grundlage eines 20 Hz Vertikalwindsignals in eine Aufwind- und eine Abwindprobe, welches erstmals eine direkte 14CO2-basierte Zerlegung der CO2-Flüsse in fossile und biogene Anteile ermöglicht. Dies ist Voraussetzung für eine unabhängige Eddy Covarianz-basierte Top-Down-Bestimmung urbaner ffCO2 Emissionen. Qualitätskontrolltests während der Zürich Kampagne zeigen, dass es keine signifikanten Unterschiede zwischen Auf- und Abwindprobennahme gibt und dass die Konzentrationsdifferenzen der Flask-Paare innerhalb von (0.02 +- 0.21) ppm mit den Differenzen der in situ Messungen übereinstimmen. Insgesamt wurden 300 Proben gesammelt, von denen 95 auf 14CO2 analysiert wurden. Diese wurden nach atmosphärischen Bedingungen während der Probenahmezeiträume gruppiert und interpretiert. Das Potenzial der 14CO2-basierten CO2-Fluss Separation konnte für Proben mit ffCO2-Differenzen größer als 1.2 ppm gezeigt werden. Für den Großteil der gesammelten Proben ist die Auswertung der ffCO2-Bestimmungen jedoch durch große Unsicherheiten aufgrund der Präzision der 14CO2-Messungen eingeschränkt. Um das volle Potenzial des ICOS REA Flask-Sammlers auszuschöpfen, sind größere Signale erforderlich, welche durch niedrigere Probenahmehöhen erreicht werden könnten."],"dc:format.medium":["application/pdf"],"dc:publisher":["Universitätsbibliothek Heidelberg"],"dc:title":["Decomposition of Urban CO2 Fluxes into Fossil and Biogenic Components using a novel Relaxed Eddy Accumulation System"],"dc:type":["masterThesis"],"thesis:degree_level":["master"],"thesis:institution_name":["Universität Heidelberg"]},"updated_at":"2026-07-24T02:31:02Z"}