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Stefan Schmolke - One of the best experts on this subject based on the ideXlab platform.
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Studies of the horizontal inhomogeneities in NO 2 concentrations above a Shipping Lane using ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements and validation with airborne imaging DOAS measurements
Atmospheric Measurement Techniques, 2019Co-Authors: André Seyler, Andreas Carlos Meier, Folkard Wittrock, Lisa Kattner, Barbara Mathieu-Üffing, Enno Peters, Andreas Richter, Thomas Ruhtz, Anja Schönhardt, Stefan SchmolkeAbstract:Abstract. This study describes a novel application of an “onion-peeling” approach to multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements of Shipping emissions aiming at investigating the strong horizontal inhomogeneities in NO2 over a Shipping Lane. To monitor ship emissions on the main Shipping route towards the port of Hamburg, a two-channel (UV and visible) MAX-DOAS instrument was deployed on the island Neuwerk in the German Bight, 6–7 km south of the main Shipping Lane. Utilizing the fact that the effective light path length in the atmosphere depends systematically on wavelength, simultaneous measurements and DOAS retrievals in the UV and visible spectral ranges are used to probe air masses at different horizontal distances to the instrument to estimate two-dimensional pollutant distributions. Two case studies have been selected to demonstrate the ability to derive the approximate plume positions in the observed area. A situation with northerly wind shows high NO2 concentrations close to the measurement site and low values in the north of the Shipping Lane. The opposite situation with southerly wind, unfavorable for the on-site in situ instrumentation, demonstrates the ability to detect enhanced NO2 concentrations several kilometers away from the instrument. Using a Gaussian plume model, in-plume NO2 volume mixing ratios can be derived from the MAX-DOAS measurements. For validation, a comparison to airborne imaging DOAS measurements during the NOSE campaign in July 2013 is performed, showing good agreement between the approximate plume position derived from the onion-peeling MAX-DOAS and the airborne measurements as well as between the derived in-plume NO2 volume mixing ratios (VMRs).
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Studies of the horizontal inhomogeneities inNO 2 concentrations above a Shipping Lane using ground-based MAX-DOAS andairborne imaging DOAS measurements
2018Co-Authors: André Seyler, Andreas Carlos Meier, Folkard Wittrock, Lisa Kattner, Barbara Mathieu-Üffing, Enno Peters, Andreas Richter, Thomas Ruhtz, Anja Schönhardt, Stefan SchmolkeAbstract:Abstract. This study describes a novel application of an onion peeling like approach to MAX-DOAS measurements of Shipping emissions aiming at investigating the strong horizontal inhomogeneities in NO2 over a Shipping Lane. To monitor ship emissions on the main Shipping route towards the port of Hamburg, a two-channel (UV and visible) MAX-DOAS instrument was deployed on the island Neuwerk in the German Bight, 6–7 km south of the main Shipping Lane. Utilizing the fact that the effective light path length in the atmosphere depends systematically on wavelength, simultaneous measurements and DOAS retrievals in the UV and visible spectral range are used to probe air masses at different horizontal distances to the instrument to estimate two-dimensional pollutant distributions. Two case-studies have been selected to demonstrate the ability to derive the approximate plume positions in the observed area. A situation with northerly wind shows high NO2 concentrations close to the measurement site and low values in the north of the Shipping Lane. The opposite situation with southerly wind, unfavorable for the on-site in situ instrumentation, demonstrates the ability to detect enhanced NO2 concentrations several kilometers away from the instrument. To validate the approach, a comparison to air-borne imaging DOAS measurements during the NOSE campaign in July 2013 is performed, showing good agreement between the approximate plume position derived from the onion peeling MAX-DOAS and the air-borne measurements. Combining synergistically information about the plume width from the air-borne measurements and about the vertical plume extent from MAX-DOAS, yields NO2 concentrations in the plume from both measurements which agree very well.
Jaime Jahncke - One of the best experts on this subject based on the ideXlab platform.
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modeling predator and prey hotspots management implications of baleen whale co occurrence with krill in central california
PLOS ONE, 2020Co-Authors: Cotton R Rockwood, Meredith L Elliott, Benjamin Saenz, Nadav Nur, Jaime JahnckeAbstract:As global ocean-bound commerce increases, managing human activities has become important in reducing conflict with threatened wildlife. This study investigates environmental factors determining abundance and distribution of blue whales (Balaenoptera musculus), humpback whales (Megaptera novaeangliae) and their prey (Euphausia pacifica and Thysanoessa spinifera) in central California. We provide insights into environmental drivers of the ecology and distribution of these species, model whale distributions and determine coincident hotspots of whales and their prey that will help decrease human threats to whales and protect critical feeding habitat. We developed separate predictive models of whale abundances (using negative binomial regression on count data) and krill abundance (using a two-part hurdlemodel combining logistic and negative binomial regressions) over a 14 year period (2004-2017). Variables included in situ surface and midwater oceanographic measures (temperature, salinity, and fluorescence), basin-scale climate indices, and bathymetric- and distance-related data. Predictions were applied to 1 km2 cells spanning the study area for May, June, July, and September during each of the 14 years of surveys to identify persistent distribution patterns. Both whales and krill were found to consistently use the northeast region of Cordell Bank, the Farallon Escarpment, and the shelf-break waters. The main identified blue whale hotspots were also krill hotspots, while co-occurrence was more limited and varied seasonally for humpback whales and krill. These results are valuable in identifying patterns in important areas of ecological interaction to assist management of whales. Areas north of Cordell Bank are of particular management concern since they overlap with the end of the San Francisco Bay northern Shipping Lane. Our findings can help decrease threats to whales, particularly in important foraging areas, by supporting implementation of vessel management and informing potential conflicts with other human uses.
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High mortality of blue, humpback and fin whales from modeling of vessel collisions on the U.S. West Coast suggests population impacts and insufficient protection
PloS one, 2017Co-Authors: R. Cotton Rockwood, John Calambokidis, Jaime JahnckeAbstract:Mortality from collisions with vessels is one of the main human causes of death for large whales. Ship strikes are rarely witnessed and the distribution of strike risk and estimates of mortality remain uncertain at best. We estimated ship strike mortality for blue humpback and fin whales in U.S. West Coast waters using a novel application of a naval encounter model. Mortality estimates from the model were far higher than current minimum estimates derived from stranding records and are closer to extrapolations adjusted for detection probabilities of dead whales. Our most conservative model estimated mortality to be 7.8x, 2.0x and 2.7x the U.S. recommended limit for blue, humpback and fin whales, respectively, suggesting that death from vessel collisions may be a significant impediment to population growth and recovery. Comparing across the study area, the majority of strike mortality occurs in waters off California, from Bodega Bay south and tends to be concentrated in a band approximately 24 Nm (44.5 km) offshore and in designated Shipping Lanes leading to and from major ports. While some mortality risk exists across nearly all West Coast waters, 74%, 82% and 65% of blue, humpback and fin whale mortality, respectively, occurs in just 10% of the study area, suggesting conservation efforts can be very effective if focused in these waters. Risk is highest in the Shipping Lanes off San Francisco and Long Beach, but only a fraction of total estimated mortality occurs in these proportionally small areas, making any conservation efforts exclusively within these areas insufficient to address overall strike mortality. We recommend combining Shipping Lane modifications and re-locations, ship speed reductions and creation of 'Areas to be Avoided' by vessels in ecologically important locations to address this significant source of whale mortality.
André Seyler - One of the best experts on this subject based on the ideXlab platform.
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Studies of the horizontal inhomogeneities in NO 2 concentrations above a Shipping Lane using ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements and validation with airborne imaging DOAS measurements
Atmospheric Measurement Techniques, 2019Co-Authors: André Seyler, Andreas Carlos Meier, Folkard Wittrock, Lisa Kattner, Barbara Mathieu-Üffing, Enno Peters, Andreas Richter, Thomas Ruhtz, Anja Schönhardt, Stefan SchmolkeAbstract:Abstract. This study describes a novel application of an “onion-peeling” approach to multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements of Shipping emissions aiming at investigating the strong horizontal inhomogeneities in NO2 over a Shipping Lane. To monitor ship emissions on the main Shipping route towards the port of Hamburg, a two-channel (UV and visible) MAX-DOAS instrument was deployed on the island Neuwerk in the German Bight, 6–7 km south of the main Shipping Lane. Utilizing the fact that the effective light path length in the atmosphere depends systematically on wavelength, simultaneous measurements and DOAS retrievals in the UV and visible spectral ranges are used to probe air masses at different horizontal distances to the instrument to estimate two-dimensional pollutant distributions. Two case studies have been selected to demonstrate the ability to derive the approximate plume positions in the observed area. A situation with northerly wind shows high NO2 concentrations close to the measurement site and low values in the north of the Shipping Lane. The opposite situation with southerly wind, unfavorable for the on-site in situ instrumentation, demonstrates the ability to detect enhanced NO2 concentrations several kilometers away from the instrument. Using a Gaussian plume model, in-plume NO2 volume mixing ratios can be derived from the MAX-DOAS measurements. For validation, a comparison to airborne imaging DOAS measurements during the NOSE campaign in July 2013 is performed, showing good agreement between the approximate plume position derived from the onion-peeling MAX-DOAS and the airborne measurements as well as between the derived in-plume NO2 volume mixing ratios (VMRs).
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Studies of the horizontal inhomogeneities inNO 2 concentrations above a Shipping Lane using ground-based MAX-DOAS andairborne imaging DOAS measurements
2018Co-Authors: André Seyler, Andreas Carlos Meier, Folkard Wittrock, Lisa Kattner, Barbara Mathieu-Üffing, Enno Peters, Andreas Richter, Thomas Ruhtz, Anja Schönhardt, Stefan SchmolkeAbstract:Abstract. This study describes a novel application of an onion peeling like approach to MAX-DOAS measurements of Shipping emissions aiming at investigating the strong horizontal inhomogeneities in NO2 over a Shipping Lane. To monitor ship emissions on the main Shipping route towards the port of Hamburg, a two-channel (UV and visible) MAX-DOAS instrument was deployed on the island Neuwerk in the German Bight, 6–7 km south of the main Shipping Lane. Utilizing the fact that the effective light path length in the atmosphere depends systematically on wavelength, simultaneous measurements and DOAS retrievals in the UV and visible spectral range are used to probe air masses at different horizontal distances to the instrument to estimate two-dimensional pollutant distributions. Two case-studies have been selected to demonstrate the ability to derive the approximate plume positions in the observed area. A situation with northerly wind shows high NO2 concentrations close to the measurement site and low values in the north of the Shipping Lane. The opposite situation with southerly wind, unfavorable for the on-site in situ instrumentation, demonstrates the ability to detect enhanced NO2 concentrations several kilometers away from the instrument. To validate the approach, a comparison to air-borne imaging DOAS measurements during the NOSE campaign in July 2013 is performed, showing good agreement between the approximate plume position derived from the onion peeling MAX-DOAS and the air-borne measurements. Combining synergistically information about the plume width from the air-borne measurements and about the vertical plume extent from MAX-DOAS, yields NO2 concentrations in the plume from both measurements which agree very well.
H. Graßl - One of the best experts on this subject based on the ideXlab platform.
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A search for large‐scale effects of ship emissions on clouds and radiation in satellite data
Journal of Geophysical Research, 2011Co-Authors: Karsten Peters, Johannes Quaas, H. GraßlAbstract:[1] Ship tracks are regarded as the most obvious manifestations of the effect of anthropogenic aerosol particles on clouds (indirect effect). However, it is not yet fully quantified whether there are climatically relevant effects on large scales beyond the narrow ship tracks visible in selected satellite images. A combination of satellite and reanalysis data is used here to analyze regions in which major Shipping Lanes cut through otherwise pristine marine environments in subtropical and tropical oceans. We expect the region downwind of a Shipping Lane is affected by the aerosol produced by Shipping emissions but not the one upwind. Thus, differences in microphysical and macrophysical cloud properties are analyzed statistically. We investigate microphysical and macrophysical cloud properties as well as the aerosol optical depth and its fine-mode fraction for the years 2005–2007 as provided for by retrievals of the two Moderate Resolution Imaging Spectroradiometer instruments. Water-cloud properties include cloud optical depth, cloud droplet effective radius, cloud top temperature, and cloud top pressure. Large-scale meteorological parameters are taken from ERA-Interim reanalysis data and microwave remote sensing (sea surface temperature). We analyze the regions of interest in a Eulerian and Lagrangian sense, i.e., sampling along Shipping Lanes and sampling along wind trajectories, respectively. No statistically significant impacts of Shipping emissions on large-scale cloud fields could be found in any of the selected regions close to major Shipping Lanes. In conclusion, the net indirect effects of aerosols from ship emissions are not large enough to be distinguishable from the natural dynamics controlling cloud presence and formation.
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A search for large-scale effects of ship emissions on clouds and radiation in satellite data
Journal of Geophysical Research: Atmospheres, 2011Co-Authors: Karsten Peters, Johannes Quaas, H. GraßlAbstract:Ship tracks are regarded as the most obvious manifestations of the effect of anthropogenic aerosol particles on clouds (indirect effect). However, it is not yet fully quantified whether there are climatically relevant effects on large scales beyond the narrow ship tracks visible in selected satellite images. A combination of satellite and reanalysis data is used here to analyze regions in which major Shipping Lanes cut through otherwise pristine marine environments in subtropical and tropical oceans. We expect the region downwind of a Shipping Lane is affected by the aerosol produced by Shipping emissions but not the one upwind. Thus, differences in microphysical and macrophysical cloud properties are analyzed statistically. We investigate microphysical and macrophysical cloud properties as well as the aerosol optical depth and its fine-mode fraction for the years 2005-2007 as provided for by retrievals of the two Moderate Resolution Imaging Spectroradiometer instruments. Water-cloud properties include cloud optical depth, cloud droplet effective radius, cloud top temperature, and cloud top pressure. Large-scale meteorological parameters are taken from ERA-Interim reanalysis data and microwave remote sensing (sea surface temperature). We analyze the regions of interest in a Eulerian and Lagrangian sense, i.e., sampling along Shipping Lanes and sampling along wind trajectories, respectively. No statistically significant impacts of Shipping emissions on large-scale cloud fields could be found in any of the selected regions close to major Shipping Lanes. In conclusion, the net indirect effects of aerosols from ship emissions are not large enough to be distinguishable from the natural dynamics controlling cloud presence and formation. Copyright 2011 by the American Geophysical Union
Marianne Glasius - One of the best experts on this subject based on the ideXlab platform.
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Contribution of ship traffic to aerosol particle concentrations downwind of a major Shipping Lane
Atmospheric Chemistry and Physics, 2014Co-Authors: Niku Kivekäs, Andreas Massling, Henrik Grythe, Robert Lange, Viktor Rusnak, Simon Carreno, Henrik Skov, Erik Swietlicki, Quynh T. Nguyen, Marianne GlasiusAbstract:Abstract. Particles in the atmosphere are of concern due to their toxic properties and effects on climate. In coastal areas, ship emissions can be a significant anthropogenic source. In this study we investigated the contribution from ship emissions to the total particle number and mass concentrations at a remote location. We studied the particle number concentration (12 to 490 nm in diameter), the mass concentration (12 to 150 nm in diameter) and number and volume size distribution of aerosol particles in ship plumes for a period of 4.5 months at Hovsore, a coastal site on the western coast of Jutland in Denmark. During episodes of western winds, the site is about 50 km downwind of a major Shipping Lane and the plumes are approximately 1 hour old when they arrive at the site. We have used a sliding percentile-based method for separating the plumes from the measured background values and to calculate the ship plume contribution to the total particle number and PM0.15 mass concentration (mass of particles below 150 nm in diameter, converted from volume assuming sphericity) at the site. The method is not limited to particle number or volume concentration, but can also be used for different chemical species in both particle and gas phase. The total number of analyzed ship plumes was 726, covering on average 19% of the time when air masses were arriving at the site over the Shipping Lane. During the periods when plumes were present, the particle concentration exceeded the background values on average by 790 cm−3 by number and 0.10 μg m−3 by mass. The corresponding daily average values were 170 cm−3 and 0.023 μg m−3, respectively. This means that the ship plumes contributed between 11 and 19% to the particle number concentration and between 9 and 18% to PM0.15 during days when air was arriving over the Shipping Lane. The estimated annual contribution from ship plumes, where all wind directions were included, was in the range of 5–8% in particle number concentration and 4–8% in PM0.15.
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Contribution of ship traffic to aerosol particle concentrations downwind of a major Shipping Lane
Atmospheric Chemistry and Physics Discussions, 2014Co-Authors: Niku Kivekäs, Andreas Massling, Henrik Grythe, Robert Lange, Viktor Rusnak, Henrik Skov, Erik Swietlicki, Quynh T. Nguyen, S. D. Carreno, Marianne GlasiusAbstract:Abstract. Particles in the atmosphere are of concern due to their toxic properties and effects on climate. In coastal areas ship emissions can be a significant anthropogenic source. In this study we investigated the contribution from ship emissions to the total particle number and mass concentrations at a remote location. We studied the particle number concentration (12 to 490 nm in diameter), the mass concentration (12 to 150 nm in diameter) and number and volume size distribution of aerosol particles in ship plumes for a period of four and a half months at Høvsøre, a coastal site on the western coast of Jutland in Denmark. During episodes of western winds the site is about 50 km downwind of a major Shipping Lane and the plumes are approximately one hour aged when they arrive at the site. We have used a sliding percentile based method for separating the plumes from the measured background values and to calculate the ship plume contribution to the total particle number and PM0.15 mass concentration (mass of particles below 150 nm in diameter, converted from volume assuming sphericity) at the site. The method is not limited to particle number or volume concentration, but can also be used for different chemical species in both particle and gas phase. The total number of analyzed ship plumes was 726, covering on average 19% of the time when air masses were arriving to the site over the Shipping Lane. During the periods when plumes were present, the particle concentration exceeded the background values on average by 790 cm−3 by number and 0.10 μg m−3 by mass. The corresponding daily average values were 170 cm−3 and 0.023 μg m−3, respectively. This means that the ship plumes contributed between 11 and 19% to the particle number concentration, and between 9 and 18% to PM0.15 during days when air was arriving over the Shipping Lane. The estimated annual contribution from ship plumes, where all wind directions were included, was in the range of 5–8% in particle number concentration and 4–8% in PM0.15.
