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Jochen Buchs - One of the best experts on this subject based on the ideXlab platform.
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validation of the transferability of membrane based fed batch shake Flask cultivations to stirred tank reactor using three different protease producing bacillus strains
Journal of Bioscience and Bioengineering, 2019Co-Authors: Janina Muller, Tobias Habicher, Anne Hutterott, Nina Musmann, Jochen BuchsAbstract:Most industrial fermentation processes are operated in fed-batch mode to overcome catabolite repression, undesired by-product formation and oxygen limitation. To maintain comparable process conditions during screening of optimal production strains, the implementation of a fed-batch mode at small scale is crucial. In this study, three different protease producing Bacillus species, Bacillus aeolius, B. licheniformis and B. pumilus, were cultivated using the previously described membrane-based fed-batch shake Flasks. Under carbon-limited conditions, catabolite repression was avoided, so that proteases were produced in all strains. Protease yields of B. aeolius and B. licheniformis increased 1.5-fold relative to batch cultivations. To validate process scalability between shake Flasks and stirred tank reactors, membrane-based fed-batch shake Flask cultivations were transferred to laboratory-scale stirred tank reactors with equal feeding rates. Despite inevitable differences between the scales such as pH control, feed supply and feed start, comparable results were achieved. Oxygen transfer rates of B. licheniformis and B. pumilus measured with the respiration activity monitoring system (RAMOS) in shake Flasks and in stirred tank reactor with an off-gas analyzer were almost identical in both cultivation systems. The protease activities referring to the total consumed glucose were also mostly comparable. A slight decrease from shake Flask to stirred tank reactor could be observed, which is presumably due to differences in pH control. This study successfully demonstrates the transferability of membrane-based fed-batch shake Flask cultivations to laboratory-scale stirred tank reactors.
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The metabolic switch can be activated in a recombinant strain of Streptomyces lividans by a low oxygen transfer rate in shake Flasks.
Microbial cell factories, 2018Co-Authors: Ramsés A. Gamboa-suasnavart, Jochen Buchs, Norma A. Valdez-cruz, Gerardo Gaytan-ortega, Greta I. Reynoso-cereceda, Daniel Cabrera-santos, Lorena López-griego, Wolf Klöckner, Mauricio A. Trujillo-roldánAbstract:In Streptomyces, understanding the switch from primary to secondary metabolism is important for maximizing the production of secondary metabolites such as antibiotics, as well as for optimizing recombinant glycoprotein production. Differences in Streptomyces lividans bacterial aggregation as well as recombinant glycoprotein production and O-mannosylation have been reported due to modifications in the shake Flask design. We hypothetized that such differences are related to the metabolic switch that occurs under oxygen-limiting conditions in the cultures. Shake Flask design was found to affect undecylprodigiosin (RED, a marker of secondary metabolism) production; the RED yield was 12 and 385 times greater in conventional normal Erlenmeyer Flasks (NF) than in baffled Flasks (BF) and coiled Flasks (CF), respectively. In addition, oxygen transfer rates (OTR) and carbon dioxide transfer rates were almost 15 times greater in cultures in CF and BF as compared with those in NF. Based on these data, we obtained respiration quotients (RQ) consistent with aerobic metabolism for CF and BF, but an RQ suggestive of anaerobic metabolism for NF. Although the metabolic switch is usually related to limitations in phosphate and nitrogen in Streptomyces sp., our results reveal that it can also be activated by low OTR, dramatically affecting recombinant glycoprotein production and O-mannosylation and increasing RED synthesis in the process.
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Three-dimensional (3D) evaluation of liquid distribution in shake Flask using an optical fluorescence technique
Journal of biological engineering, 2017Co-Authors: Amizon Azizan, Jochen BuchsAbstract:Biotechnological development in shake Flask necessitates vital engineering parameters e.g. volumetric power input, mixing time, gas liquid mass transfer coefficient, hydromechanical stress and effective shear rate. Determination and optimization of these parameters through experiments are labor-intensive and time-consuming. Computational Fluid Dynamics (CFD) provides the ability to predict and validate these parameters in bioprocess engineering. This work provides ample experimental data which are easily accessible for future validations to represent the hydrodynamics of the fluid flow in the shake Flask. A non-invasive measuring technique using an optical fluorescence method was developed for shake Flasks containing a fluorescent solution with a waterlike viscosity at varying filling volume (VL = 15 to 40 mL) and shaking frequency (n = 150 to 450 rpm) at a constant shaking diameter (do = 25 mm). The method detected the leading edge (LB) and tail of the rotating bulk liquid (TB) relative to the direction of the centrifugal acceleration at varying circumferential heights from the base of the shake Flask. The determined LB and TB points were translated into three-dimensional (3D) circumferential liquid distribution plots. The maximum liquid height (Hmax) of the bulk liquid increased with increasing filling volume and shaking frequency of the shaking Flask, as expected. The toroidal shapes of LB and TB are clearly asymmetrical and the measured TB differed by the elongation of the liquid particularly towards the torus part of the shake Flask. The 3D liquid distribution data collected at varying filling volume and shaking frequency, comprising of LB and TB values relative to the direction of the centrifugal acceleration are essential for validating future numerical solutions using CFD to predict vital engineering parameters in shake Flask.
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Improvement and scale-down of a Trichoderma reesei shake Flask protocol to microtiter plates enables high-throughput screening.
Journal of bioscience and bioengineering, 2014Co-Authors: Heiner Giese, Kristina Meier, Paulien Kruithof, Michaela Sieben, Elena Antonov, Ronald Hommes, Jochen BuchsAbstract:Nowadays, high-throughput screening is essential for determining the best microbial strains and fermentation conditions. Although microtiter plates allow higher throughput in screening than shake Flasks, they do not guarantee sufficient oxygen supply if operated at unsuitable conditions. This is especially the case in viscous fermentations, potentially leading to poor liquid movement and surface growth. Therefore, in this study, two aims were pursued. First, an industrial Trichoderma reesei shake Flask protocol is improved with respect to oxygen supply and production. Second, this improved shake Flask protocol is scaled down into microtiter plate under consideration of similar oxygen supply. For this purpose, the respiration activity monitoring system (RAMOS) was applied. An approach based on a sulfite system was introduced to ensure equal maximum oxygen transfer capacities (OTRmax) in microtiter plates and shake Flasks. OTRmax-values of 250 mL shake Flasks and 24-well microtiter plates were determined in a wide range of operating conditions. These sulfite datasets were used to identify operating conditions leading to the same oxygen supply for T. reesei in shake Flasks and 24-well microtiter plates. For 24-well microtiter plates, the shake Flask OTRmax of 20 mmol/L/h of an industrial protocol was obtained under the following optimal operating conditions: 1 mL filling volume per well, 200 rpm shaking frequency and 50 mm shaking diameter. With these conditions almost identical oxygen transfer rates and product concentrations were measured in both scales. The proposed approach is a fast and accurate means to scale-down established screening procedures into microtiter plates to achieve high-throughput.
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Potential errors in conventional DOT measurement techniques in shake Flasks and verification using a rotating flexitube optical sensor.
BMC biotechnology, 2011Co-Authors: Sven Hansen, Frank Kensy, Andreas Kaser, Jochen BuchsAbstract:Background Dissolved oxygen tension (DOT) is an important parameter for evaluating a bioprocess. Conventional means to measure DOT in shake Flasks using fixed Clark-type electrodes immersed in the bulk liquid are problematic, because they inherently alter the hydrodynamics of the systems. Other approaches to measure DOT that apply fluorescing sensor spots fixed at the inside wall of a shake Flask are also suboptimal. At low filling volumes for cultivating microorganisms with a high oxygen demand, the measured DOT signal may be erroneous. Here, the sensor spot is sometimes exposed to gas in the head space of the Flask. Merely repositioning the sensor spot elsewhere in the Flask does not address this problem, since there is no location in the shake Flask that is always covered by the rotating bulk liquid. Thus, the aim of this prospective study is first, to verify the systemic error of Clark-type electrodes for measuring DOT in shake Flasks. The second principle aim is to use the newly built "flexitube optical sensor" to verify potential errors in conventional optical DOT measurements based on fixed sensor spots.
Sebastien Conil - One of the best experts on this subject based on the ideXlab platform.
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a dedicated Flask sampling strategy developed for integrated carbon observation system icos stations based on co2 and co measurements and stochastic time inverted lagrangian transport stilt footprint modelling
Atmospheric Chemistry and Physics, 2020Co-Authors: Ingeborg Levin, Ute Karstens, Markus Eritt, Fabian Maier, Sabrina Arnold, Daniel Rzesanke, Samuel Hammer, Michel Ramonet, Gabriela Vitkova, Sebastien ConilAbstract:Abstract. In situ CO2 and CO measurements from five Integrated Carbon Observation System (ICOS) atmosphere stations have been analysed together with footprint model runs from the regional Stochastic Time-Inverted Lagrangian Transport (STILT) model to develop a dedicated strategy for Flask sampling with an automated sampler. Flask sampling in ICOS has three different purposes, namely (1) to provide an independent quality control for in situ observations, (2) to provide representative information on atmospheric components currently not monitored in situ at the stations, and (3) to collect samples for 14CO2 analysis that are significantly influenced by fossil fuel CO2 ( ffCO2 ) emission areas. Based on the existing data and experimental results obtained at the Heidelberg pilot station with a prototype Flask sampler, we suggest that single Flask samples are collected regularly every third day around noon or in the afternoon from the highest level of a tower station. Air samples shall be collected over 1 h, with equal temporal weighting, to obtain a true hourly mean. At all stations studied, more than 50 % of Flasks collected around midday will likely be sampled during low ambient variability ( parts per million (ppm) standard deviation of 1 min values). Based on a first application at the Hohenpeisenberg ICOS site, such Flask data are principally suitable for detecting CO2 concentration biases larger than 0.1 ppm with a 1 σ confidence level between Flask and in situ observations from only five Flask comparisons. In order to have a maximum chance to also sample ffCO2 emission areas, additional Flasks are collected on all other days in the afternoon. To check if the ffCO2 component will indeed be large in these samples, we use the continuous in situ CO observations. The CO deviation from an estimated background value is determined the day after each Flask sampling, and depending on this offset, an automated decision is made as to whether a Flask shall be retained for 14CO2 analysis. It turned out that, based on existing data, ffCO2 events of more than 4–5 ppm that would allow ffCO2 estimates with an uncertainty below 30 % were very rare at all stations studied, particularly in summer (only zero to five events per month from May to August). During the other seasons, events could be collected more frequently. The strategy developed in this project is currently being implemented at the ICOS stations.
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a dedicated Flask sampling strategy developed for icos stations based on co 2 and co measurements and stilt footprint modelling
Atmospheric Chemistry and Physics, 2020Co-Authors: Ingeborg Levin, Ute Karstens, Markus Eritt, Fabian Maier, Sabrina Arnold, Daniel Rzesanke, Samuel Hammer, Michel Ramonet, Gabriela Vitkova, Sebastien ConilAbstract:Abstract. In situ CO2 and CO measurements from five atmospheric ICOS (Integrated Carbon Observation System) stations have been analysed together with footprint model runs from the regional transport model STILT, to develop a dedicated strategy for Flask sampling with an automated sampler. Flask sampling in ICOS has three different purposes: (1) Provide an independent quality control for in situ observations, (2) provide representative information on atmospheric components currently not monitored in situ at the stations, (3) collect samples for 14CO2 analysis that are significantly influenced by fossil fuel CO2 (ffCO2) emission areas. Based on the existing data and experimental results obtained at the Heidelberg pilot station with a prototype Flask sampler, we suggest that single Flask samples should be collected regularly every third day around noon/afternoon from the highest level of a tower station. Air samples shall be collected over one hour with equal temporal weighting to obtain a true hourly mean. At all stations studied, more than 50 % of Flasks to be collected around mid-day will likely be sampled during low ambient variability (
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A dedicated Flask sampling strategy developed for Integrated Carbon Observation System (ICOS) stations based on CO2 and CO measurements and Stochastic Time-Inverted Lagrangian Transport (STILT) footprint modelling
Atmospheric Chemistry and Physics, 2020Co-Authors: Ingeborg Levin, Ute Karstens, Markus Eritt, Fabian Maier, Sabrina Arnold, Daniel Rzesanke, Samuel Hammer, Michel Ramonet, Gabriela Vitkova, Sebastien ConilAbstract:In situ CO 2 and CO measurements from five Integrated Carbon Observation System (ICOS) atmosphere stations have been analysed together with footprint model runs from the regional Stochastic Time-Inverted Lagrangian Transport (STILT) model to develop a dedicated strategy for Flask sampling with an automated sampler. Flask sampling in ICOS has three different purposes, namely (1) to provide an independent quality control for in situ observations, (2) to provide representative information on atmospheric components currently not monitored in situ at the stations, and (3) to collect samples for 14 CO 2 analysis that are significantly influenced by fossil fuel CO 2 (ffCO 2) emission areas. Based on the existing data and experimental results obtained at the Heidelberg pilot station with a prototype Flask sam-pler, we suggest that single Flask samples are collected regularly every third day around noon or in the afternoon from the highest level of a tower station. Air samples shall be collected over 1 h, with equal temporal weighting, to obtain a true hourly mean. At all stations studied, more than 50 % of Flasks collected around midday will likely be sampled during low ambient variability (
Ulrike Maier - One of the best experts on this subject based on the ideXlab platform.
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Calculating liquid distribution in shake Flasks on rotary shakers at waterlike viscosities
Biochemical Engineering Journal, 2007Co-Authors: Jochen Buchs, Ulrike Maier, Stefan Lotter, Cyril P. PeterAbstract:Abstract Screening projects in biotechnological industry performed in shake Flasks risk unwanted development if not failure, when operating conditions are not suitable. Limited knowledge, however, is available for the mechanistical design of operating conditions in this type of bioreactor. The fundamental engineering variables are influenced by the geometry of the rotating bulk liquid: for momentum transfer, the contact area between the liquid and the Flask inner wall is the friction area, and for mass transfer, the wetted wall exposed to the surrounding air is the mass exchange area. To assess the geometry of the rotating bulk liquid moving inside a shaken Erlenmeyer Flask, with respect to the mentioned important engineering variables mentioned, a mechanistical model for the liquid distribution in shake Flasks is described in this work. The model is based on a superposition of two individual movements: a circular translatoric movement and a rotation of the Flask counteracting the first motion to keep the shake Flasks’ spatial orientation. If the effect of viscosity is neglected, the liquid distribution results in an exactly symmetrical paraboloid. A comparison of the calculated liquid distribution with photographs shows very good qualitative agreement of the real liquid distributions by the model equations. Quantitative agreement has been demonstrated by comparison of the liquid height. Furthermore, model equations are presented for the calculation of the contact area between the liquid and the Flask wall. This may eventually lead to a prediction of the volumetric power consumption. Similarly, the calculation of the mass transfer area (i.e. liquid surface area and wetted Flask wall) is presented.
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Advances in understanding and modeling the gas–liquid mass transfer in shake Flasks
Biochemical Engineering Journal, 2004Co-Authors: Ulrike Maier, Mario Losen, Jochen BuchsAbstract:Abstract The gas–liquid mass transfer in 250 ml shake Flasks has previously been sucessfully modelled on basis of Higbie’s penetration theory. The current contribution presents advances in understanding and modelling the gas–liquid mass transfer in shake Flasks at waterlike liquid viscosity in Flask sizes between 50 and 1000 ml. An experimental investigation of the maximum gas–liquid mass transfer capacity OTRmax using the sodium sulphite system was extended to relative filling volumes of 4–16%, shaking diameters of 1.25, 2.5, 5, 7, 10 cm and shaking frequencies of 50–500 rpm for the above Flask sizes. Simultaneously, the previous model of the gas–liquid mass transfer was extended to a “two sub-reactor model” to account for different mechanisms of mass transfer in the liquid film on the Flask wall and the bulk of the liquid rotating within the Flask. The shake Flask is for the first time considered to be a two-reactor system consisting of a stirred tank reactor (bulk liquid) and a film reactor (film on Flask wall and base). The mass transfer into the film on the Flask wall and base at “in-phase” operating conditions is described by Higbie’s penetration theory. Two different mass transfer theories were applied to successfully describe the mass transfer into the bulk liquid: a model by Kawase and Moo-Young and a model by Gnielinski. The agreement between the new modelling approach, which requires absolutely no fitting parameters and the experimental is within ±30%. The applicability of the models to a biological system was shown using a Pichia pastoris culture. This is particularly notable since geometrically non-similar liquid distributions in very different sizes of shaking Flasks are covered. A comparable description of the gas–liquid mass transfer in bubble aerated reactors like stirred tanks is absolutely out of reach. A spatially- and time-resolved consideration of the mass transfer in the liquid film on the Flask wall and base has shown that the validity of Higbie’s theory sensitively depends on the film thickness and contact time.
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Impact of out-of-phase conditions on screening results in shaking Flask experiments
Biochemical Engineering Journal, 2004Co-Authors: Cyril P. Peter, Ulrike Maier, Stefan Lotter, Jochen BuchsAbstract:Abstract Screening projects dealing with filamentous microorganisms in shaking flaks may generate strains showing a less filamentous morphology with a decreased apparent viscosity of the fermentation broth. The apparent viscosity of the fermentation broths showing pseudo-plastic flow behavior can be calculated by known relations, if the average shear rate is known. A method is presented allowing the determination of the relevant average shear rate, and thus, apparent viscosity of the fermentation broth at given operating conditions of the shaking Flask experiment. At elevated apparent viscosity, shaking Flask fermentations are subject to the recently discovered out-of-phase conditions. Measurements of the oxygen transfer capacity (OTRmax) in a highly viscous fluid have clearly shown reduced mass transfer, and therefore a reduced productivity of the investigated strains, when out-of-phase conditions are present. This leads to a selection pressure preferring a less filamentous morphology accompanied by lower apparent viscosity in screening projects in shaking Flasks. In two completely different cases, the apparent broth viscosity of several consecutive strain generations was investigated. The later strain generation showed a lower apparent broth viscosity compared to the predecessor strain. In a third case, it was shown that out-of-phase conditions prevent the development of an improved culture medium.
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characterisation of the gas liquid mass transfer in shaking bioreactors
Biochemical Engineering Journal, 2001Co-Authors: Ulrike Maier, Jochen BuchsAbstract:Abstract The maximum gas–liquid mass transfer capacity of 250 ml shaking Flasks on orbital shaking machines has been experimentally investigated using the sulphite oxidation method under variation of the shaking frequency, shaking diameter, filling volume and viscosity of the medium. The distribution of the liquid within the Flask has been modelled by the intersection between the rotational hyperboloid of the liquid and the inner wall of the shaking Flask. This model allows for the calculation of the specific exchange area ( a ), the mass transfer coefficient ( k L ) and the maximum oxygen transfer capacity (OTR max ) for given operating conditions and requires no fitting parameters. The model agrees well with the experimental results. It was furthermore shown that the liquid film on the Flask wall contributes significantly to the specific mass transfer area ( a ) and to the oxygen transfer rate (OTR).
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Power consumption in shaking Flasks on rotary shaking machines: I. Power consumption measurement in unbaffled Flasks at low liquid viscosity
Biotechnology and bioengineering, 2000Co-Authors: Jochen Buchs, Ulrike Maier, Claudia Milbradt, Bernd ZoelsAbstract:In this first article of a series a new method is introduced that enables the accurate determination of the power consumption in a shaking Flask. The method is based on torque measurements in the drive and appropriate compensation of the friction losses. The results for unbaffled shaking Flasks at low viscosities are presented after varying shaking frequency, Flask size, filling volume, shaking diameter, and surface quality (hydrophilic and hydrophobic) of the inner Flask walls. The order of magnitude of the values of power consumption in shaking Flasks is equal to, or even higher than, the values typical for agitated tank bioreactors. A physically based model equation for shaking Flasks is derived that introduces a modified power number and a resulting constant as the only fitting parameter. With this equation, the measured results are correlated with sufficient accuracy. For the first time, comprehensive data for the power consumption in unbaffled shaking Flasks at low viscosity is available, giving a detailed picture of the influences of the different variables. © 2000 John Wiley & Sons, Inc. Biotechnol Bioeng 68: 589–593, 2000.
Ingeborg Levin - One of the best experts on this subject based on the ideXlab platform.
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a dedicated Flask sampling strategy developed for integrated carbon observation system icos stations based on co2 and co measurements and stochastic time inverted lagrangian transport stilt footprint modelling
Atmospheric Chemistry and Physics, 2020Co-Authors: Ingeborg Levin, Ute Karstens, Markus Eritt, Fabian Maier, Sabrina Arnold, Daniel Rzesanke, Samuel Hammer, Michel Ramonet, Gabriela Vitkova, Sebastien ConilAbstract:Abstract. In situ CO2 and CO measurements from five Integrated Carbon Observation System (ICOS) atmosphere stations have been analysed together with footprint model runs from the regional Stochastic Time-Inverted Lagrangian Transport (STILT) model to develop a dedicated strategy for Flask sampling with an automated sampler. Flask sampling in ICOS has three different purposes, namely (1) to provide an independent quality control for in situ observations, (2) to provide representative information on atmospheric components currently not monitored in situ at the stations, and (3) to collect samples for 14CO2 analysis that are significantly influenced by fossil fuel CO2 ( ffCO2 ) emission areas. Based on the existing data and experimental results obtained at the Heidelberg pilot station with a prototype Flask sampler, we suggest that single Flask samples are collected regularly every third day around noon or in the afternoon from the highest level of a tower station. Air samples shall be collected over 1 h, with equal temporal weighting, to obtain a true hourly mean. At all stations studied, more than 50 % of Flasks collected around midday will likely be sampled during low ambient variability ( parts per million (ppm) standard deviation of 1 min values). Based on a first application at the Hohenpeisenberg ICOS site, such Flask data are principally suitable for detecting CO2 concentration biases larger than 0.1 ppm with a 1 σ confidence level between Flask and in situ observations from only five Flask comparisons. In order to have a maximum chance to also sample ffCO2 emission areas, additional Flasks are collected on all other days in the afternoon. To check if the ffCO2 component will indeed be large in these samples, we use the continuous in situ CO observations. The CO deviation from an estimated background value is determined the day after each Flask sampling, and depending on this offset, an automated decision is made as to whether a Flask shall be retained for 14CO2 analysis. It turned out that, based on existing data, ffCO2 events of more than 4–5 ppm that would allow ffCO2 estimates with an uncertainty below 30 % were very rare at all stations studied, particularly in summer (only zero to five events per month from May to August). During the other seasons, events could be collected more frequently. The strategy developed in this project is currently being implemented at the ICOS stations.
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a dedicated Flask sampling strategy developed for icos stations based on co 2 and co measurements and stilt footprint modelling
Atmospheric Chemistry and Physics, 2020Co-Authors: Ingeborg Levin, Ute Karstens, Markus Eritt, Fabian Maier, Sabrina Arnold, Daniel Rzesanke, Samuel Hammer, Michel Ramonet, Gabriela Vitkova, Sebastien ConilAbstract:Abstract. In situ CO2 and CO measurements from five atmospheric ICOS (Integrated Carbon Observation System) stations have been analysed together with footprint model runs from the regional transport model STILT, to develop a dedicated strategy for Flask sampling with an automated sampler. Flask sampling in ICOS has three different purposes: (1) Provide an independent quality control for in situ observations, (2) provide representative information on atmospheric components currently not monitored in situ at the stations, (3) collect samples for 14CO2 analysis that are significantly influenced by fossil fuel CO2 (ffCO2) emission areas. Based on the existing data and experimental results obtained at the Heidelberg pilot station with a prototype Flask sampler, we suggest that single Flask samples should be collected regularly every third day around noon/afternoon from the highest level of a tower station. Air samples shall be collected over one hour with equal temporal weighting to obtain a true hourly mean. At all stations studied, more than 50 % of Flasks to be collected around mid-day will likely be sampled during low ambient variability (
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A dedicated Flask sampling strategy developed for Integrated Carbon Observation System (ICOS) stations based on CO2 and CO measurements and Stochastic Time-Inverted Lagrangian Transport (STILT) footprint modelling
Atmospheric Chemistry and Physics, 2020Co-Authors: Ingeborg Levin, Ute Karstens, Markus Eritt, Fabian Maier, Sabrina Arnold, Daniel Rzesanke, Samuel Hammer, Michel Ramonet, Gabriela Vitkova, Sebastien ConilAbstract:In situ CO 2 and CO measurements from five Integrated Carbon Observation System (ICOS) atmosphere stations have been analysed together with footprint model runs from the regional Stochastic Time-Inverted Lagrangian Transport (STILT) model to develop a dedicated strategy for Flask sampling with an automated sampler. Flask sampling in ICOS has three different purposes, namely (1) to provide an independent quality control for in situ observations, (2) to provide representative information on atmospheric components currently not monitored in situ at the stations, and (3) to collect samples for 14 CO 2 analysis that are significantly influenced by fossil fuel CO 2 (ffCO 2) emission areas. Based on the existing data and experimental results obtained at the Heidelberg pilot station with a prototype Flask sam-pler, we suggest that single Flask samples are collected regularly every third day around noon or in the afternoon from the highest level of a tower station. Air samples shall be collected over 1 h, with equal temporal weighting, to obtain a true hourly mean. At all stations studied, more than 50 % of Flasks collected around midday will likely be sampled during low ambient variability (
Daniel Rzesanke - One of the best experts on this subject based on the ideXlab platform.
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a dedicated Flask sampling strategy developed for integrated carbon observation system icos stations based on co2 and co measurements and stochastic time inverted lagrangian transport stilt footprint modelling
Atmospheric Chemistry and Physics, 2020Co-Authors: Ingeborg Levin, Ute Karstens, Markus Eritt, Fabian Maier, Sabrina Arnold, Daniel Rzesanke, Samuel Hammer, Michel Ramonet, Gabriela Vitkova, Sebastien ConilAbstract:Abstract. In situ CO2 and CO measurements from five Integrated Carbon Observation System (ICOS) atmosphere stations have been analysed together with footprint model runs from the regional Stochastic Time-Inverted Lagrangian Transport (STILT) model to develop a dedicated strategy for Flask sampling with an automated sampler. Flask sampling in ICOS has three different purposes, namely (1) to provide an independent quality control for in situ observations, (2) to provide representative information on atmospheric components currently not monitored in situ at the stations, and (3) to collect samples for 14CO2 analysis that are significantly influenced by fossil fuel CO2 ( ffCO2 ) emission areas. Based on the existing data and experimental results obtained at the Heidelberg pilot station with a prototype Flask sampler, we suggest that single Flask samples are collected regularly every third day around noon or in the afternoon from the highest level of a tower station. Air samples shall be collected over 1 h, with equal temporal weighting, to obtain a true hourly mean. At all stations studied, more than 50 % of Flasks collected around midday will likely be sampled during low ambient variability ( parts per million (ppm) standard deviation of 1 min values). Based on a first application at the Hohenpeisenberg ICOS site, such Flask data are principally suitable for detecting CO2 concentration biases larger than 0.1 ppm with a 1 σ confidence level between Flask and in situ observations from only five Flask comparisons. In order to have a maximum chance to also sample ffCO2 emission areas, additional Flasks are collected on all other days in the afternoon. To check if the ffCO2 component will indeed be large in these samples, we use the continuous in situ CO observations. The CO deviation from an estimated background value is determined the day after each Flask sampling, and depending on this offset, an automated decision is made as to whether a Flask shall be retained for 14CO2 analysis. It turned out that, based on existing data, ffCO2 events of more than 4–5 ppm that would allow ffCO2 estimates with an uncertainty below 30 % were very rare at all stations studied, particularly in summer (only zero to five events per month from May to August). During the other seasons, events could be collected more frequently. The strategy developed in this project is currently being implemented at the ICOS stations.
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a dedicated Flask sampling strategy developed for icos stations based on co 2 and co measurements and stilt footprint modelling
Atmospheric Chemistry and Physics, 2020Co-Authors: Ingeborg Levin, Ute Karstens, Markus Eritt, Fabian Maier, Sabrina Arnold, Daniel Rzesanke, Samuel Hammer, Michel Ramonet, Gabriela Vitkova, Sebastien ConilAbstract:Abstract. In situ CO2 and CO measurements from five atmospheric ICOS (Integrated Carbon Observation System) stations have been analysed together with footprint model runs from the regional transport model STILT, to develop a dedicated strategy for Flask sampling with an automated sampler. Flask sampling in ICOS has three different purposes: (1) Provide an independent quality control for in situ observations, (2) provide representative information on atmospheric components currently not monitored in situ at the stations, (3) collect samples for 14CO2 analysis that are significantly influenced by fossil fuel CO2 (ffCO2) emission areas. Based on the existing data and experimental results obtained at the Heidelberg pilot station with a prototype Flask sampler, we suggest that single Flask samples should be collected regularly every third day around noon/afternoon from the highest level of a tower station. Air samples shall be collected over one hour with equal temporal weighting to obtain a true hourly mean. At all stations studied, more than 50 % of Flasks to be collected around mid-day will likely be sampled during low ambient variability (
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A dedicated Flask sampling strategy developed for Integrated Carbon Observation System (ICOS) stations based on CO2 and CO measurements and Stochastic Time-Inverted Lagrangian Transport (STILT) footprint modelling
Atmospheric Chemistry and Physics, 2020Co-Authors: Ingeborg Levin, Ute Karstens, Markus Eritt, Fabian Maier, Sabrina Arnold, Daniel Rzesanke, Samuel Hammer, Michel Ramonet, Gabriela Vitkova, Sebastien ConilAbstract:In situ CO 2 and CO measurements from five Integrated Carbon Observation System (ICOS) atmosphere stations have been analysed together with footprint model runs from the regional Stochastic Time-Inverted Lagrangian Transport (STILT) model to develop a dedicated strategy for Flask sampling with an automated sampler. Flask sampling in ICOS has three different purposes, namely (1) to provide an independent quality control for in situ observations, (2) to provide representative information on atmospheric components currently not monitored in situ at the stations, and (3) to collect samples for 14 CO 2 analysis that are significantly influenced by fossil fuel CO 2 (ffCO 2) emission areas. Based on the existing data and experimental results obtained at the Heidelberg pilot station with a prototype Flask sam-pler, we suggest that single Flask samples are collected regularly every third day around noon or in the afternoon from the highest level of a tower station. Air samples shall be collected over 1 h, with equal temporal weighting, to obtain a true hourly mean. At all stations studied, more than 50 % of Flasks collected around midday will likely be sampled during low ambient variability (
