scholarly journals Investigation of a potential HCHO measurement artifact from ISOPOOH

2016 ◽  
Vol 9 (9) ◽  
pp. 4561-4568 ◽  
Author(s):  
Jason M. St. Clair ◽  
Jean C. Rivera-Rios ◽  
John D. Crounse ◽  
Eric Praske ◽  
Michelle J. Kim ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Laboratory Experiments ◽  
First Generation ◽  
Atmospheric Composition ◽  
Previous Exposure ◽  
Methyl Vinyl ◽  
Isoprene Oxidation ◽  
Measurement Artifact ◽  
Recent Laboratory

Abstract. Recent laboratory experiments have shown that a first generation isoprene oxidation product, ISOPOOH, can decompose to methyl vinyl ketone (MVK) and methacrolein (MACR) on instrument surfaces, leading to overestimates of MVK and MACR concentrations. Formaldehyde (HCHO) was suggested as a decomposition co-product, raising concern that in situ HCHO measurements may also be affected by an ISOPOOH interference. The HCHO measurement artifact from ISOPOOH for the NASA In Situ Airborne Formaldehyde instrument (ISAF) was investigated for the two major ISOPOOH isomers, (1,2)-ISOPOOH and (4,3)-ISOPOOH, under dry and humid conditions. The dry conversion of ISOPOOH to HCHO was 3 ± 2 % and 6 ± 4 % for (1,2)-ISOPOOH and (4,3)-ISOPOOH, respectively. Under humid (relative humidity of 40–60 %) conditions, conversion to HCHO was 6 ± 4 % for (1,2)-ISOPOOH and 10 ± 5 % for (4,3)-ISOPOOH. The measurement artifact caused by conversion of ISOPOOH to HCHO in the ISAF instrument was estimated for data obtained on the 6 September 2013 flight of the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) campaign. Prompt ISOPOOH conversion to HCHO was the source of < 4 % of the observed HCHO, including in the high-isoprene boundary layer. Time-delayed conversion, where previous exposure to ISOPOOH affects measured HCHO later in the flight, was conservatively estimated to be < 10 % of observed HCHO, and is significant only when high ISOPOOH sampling periods immediately precede periods of low HCHO.

scholarly journals Investigation of a potential HCHO measurement artifact from ISOPOOH

2016 ◽  
Author(s):  
Jason M. St. Clair ◽  
Jean C. Rivera-Rios ◽  
John D. Crounse ◽  
Eric Praske ◽  
Michelle J. Kim ◽  
...  
Keyword(s):  
Oxidation Product ◽  
Laboratory Experiments ◽  
First Generation ◽  
Vinyl Ketone ◽  
Atmospheric Composition ◽  
Methyl Vinyl ◽  
Isoprene Oxidation ◽  
Measurement Artifact ◽  
Recent Laboratory

Abstract. Recent laboratory experiments have shown that a first generation isoprene oxidation product, ISOPOOH, can decompose to methyl vinyl ketone (MVK) and methacrolein (MACR) on instrument surfaces, leading to overestimates of MVK and MACR concentrations. Formaldehyde (HCHO) was suggested as a decomposition co-product, raising concern that in situ HCHO measurements may also be affected by an ISOPOOH interference. The HCHO measurement artifact from ISOPOOH for the NASA In Situ Airborne Formaldehyde instrument (ISAF) was investigated for the two major ISOPOOH isomers, (1,2)-ISOPOOH and (4,3)-ISOPOOH, under dry and humid conditions. The dry conversion of ISOPOOH to HCHO was 3 ± 2 % and 6 ± 4 % for (1,2)-ISOPOOH and (4,3)-ISOPOOH, respectively. Under humid (RH = 40–60 %) conditions, conversion to HCHO was 6 ± 4 % for (1,2)-ISOPOOH and 10 ± 5 % for (4,3)-ISOPOOH. The measurement artifact caused by conversion of ISOPOOH to HCHO in the ISAF instrument was estimated for data obtained on the 2013 September 6 flight of the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) campaign. Prompt ISOPOOH conversion to HCHO was the source for

scholarly journals Ground-based remote sensing of O<sub>3</sub> by high- and medium-resolution FTIR spectrometers over the Mexico City basin

2017 ◽  
Vol 10 (7) ◽  
pp. 2703-2725 ◽  
Author(s):  
Eddy F. Plaza-Medina ◽  
Wolfgang Stremme ◽  
Alejandro Bezanilla ◽  
Michel Grutter ◽  
Matthias Schneider ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Boundary Layer ◽  
Mexico City ◽  
Atmospheric Composition ◽  
Horizontal Distance ◽  
Solar Absorption ◽  
Surface Data ◽  
Medium Resolution

Abstract. We present atmospheric ozone (O3) profiles measured over central Mexico between November 2012 and February 2014 from two different ground-based FTIR (Fourier transform infrared) solar absorption experiments. The first instrument offers very high-resolution spectra and contributes to NDACC (Network for the Detection of Atmospheric Composition Change). It is located at a mountain observatory about 1700 m above the Mexico City basin. The second instrument has a medium spectral resolution and is located inside Mexico City at a horizontal distance of about 60 km from the mountain observatory. It is documented that the retrieval with the high- and medium-resolution experiments provides O3 variations for four and three independent atmospheric altitude ranges, respectively, and the theoretically estimated errors of these profile data are mostly within 10 %. The good quality of the data is empirically demonstrated above the tropopause by intercomparing the two FTIR O3 data, and for the boundary layer by comparing the Mexico City FTIR O3 data with in situ O3 surface data. Furthermore, we develop a combined boundary layer O3 remote sensing product that uses the retrieval results of both FTIR experiments, and we use theoretical and empirical evaluations to document the improvements that can be achieved by such a combination.

scholarly journals Two case studies on the interaction of large-scale transport, mesoscale photochemistry, and boundary-layer processes on the lower tropospheric ozone dynamics in early spring

2001 ◽  
Vol 19 (4) ◽  
pp. 469-486 ◽  
Author(s):  
S. Brönnimann ◽  
F. C. Siegrist ◽  
W. Eugster ◽  
R. Cattin ◽  
C. Sidle ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Large Scale ◽  
Lower Troposphere ◽  
Early Spring ◽  
Atmospheric Composition ◽  
Late Winter ◽  
Chemical Production ◽  
Ozone Concentrations ◽  
Boundary Layer Ozone

Abstract. The vertical distribution of ozone in the lower troposphere over the Swiss Plateau is investigated in detail for two episodes in early spring (February 1998 and March 1999). Profile measurements of boundary-layer ozone performed during two field campaigns with a tethered balloon sounding system and a kite are investigated using regular aerological and ozone soundings from a nearby site, measurements from monitoring stations at various altitudes, backward trajectories, and synoptic analyses of meteorological fields. Additionally, the effect of in situ photochemistry was estimated for one of the episodes employing the Metphomod Eulerian photochemical model. Although the meteorological situations were completely different, both cases had elevated layers with high ozone concentrations, which is not untypical for late winter and early spring. In the February episode, the highest ozone concentrations of 55 to 60 ppb, which were found at around 1100 m asl, were partly advected from Southern France, but a considerable contribution of in situ photochemistry is also predicted by the model. Below that elevation, the local chemical sinks and surface deposition probably overcompensated chemical production, and the vertical ozone distribution was governed by boundary-layer dynamics. In the March episode, the results suggest that ozone-rich air parcels, probably of stratospheric or upper tropospheric origin, were advected aloft the boundary layer on the Swiss Plateau.Key words. Atmospheric composition and structure (pollution – urban and regional; troposphere – composition and  chemistry) – Meteorology and atmospheric dynamics (mesoscale meteorology)

scholarly journals Ground-based remote sensing of O<sub>3</sub> by high and medium resolution FTIR spectrometers over the Mexico City basin

2017 ◽  
Author(s):  
Eddy F. Plaza-Medina ◽  
Wolfgang Stremme ◽  
Alejandro Bezanilla ◽  
Michel Grutter ◽  
Matthias Schneider ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Boundary Layer ◽  
Mexico City ◽  
Atmospheric Composition ◽  
Horizontal Distance ◽  
Solar Absorption ◽  
Surface Data ◽  
Medium Resolution

Abstract. We present atmospheric ozone (O3) profiles measured over central Mexico between November 2012 and February 2014 by two different ground-based FTIR (Fourier transform infrared) solar absorption experiments. The first instrument offers very high resolution spectra and contributes to NDACC (Network for the Detection of Atmospheric Composition Change). It is located at a mountain observatory about 1700 m above the Mexico City basin. The second instrument has a medium spectral resolution and is located inside of Mexico City at a horizontal distance of about 60 km to the mountain observatory. It is documented that the retrieval with the high and medium resolution experiments give O3 variations for three and four independent atmospheric altitude ranges, respectively, whereby the theoretically estimated errors of these profile data are mostly within 10 %. The good quality of the data is empirically demonstrated: above the tropopause by intercomparing the two FTIR O3 data and for the boundary layer by comparing the Mexico City FTIR O3 data with in-situ O3 surface data. Furthermore, we develop a combined boundary layer O3 remote sensing product that uses the retrieval results of both FTIR experiments and demonstrate theoretically and empirically the improvements achieved by such combination.

Thermal gravimetric analysis of in-situ crosslinked nanocellulose whiskers • poly(methyl vinyl ether-co-maleic acid) • polyethylene glycol

TAPPI Journal ◽  
2011 ◽  
Vol 10 (4) ◽  
pp. 29-33
Author(s):  
LEE A. GOETZ ◽  
AJI P. MATHEW ◽  
KRISTIINA OKSMAN ◽  
ARTHUR J. RAGAUSKAS
Keyword(s):  
Thermal Stability ◽  
Polyethylene Glycol ◽  
Vinyl Ether ◽  
Thermal Gravimetric Analysis ◽  
Maleic Acid ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Methyl Vinyl ◽  
Methyl Vinyl Ether

The thermal stability and decomposition of in-situ crosslinked nanocellulose whiskers – poly(methyl vinyl ether-co-maleic acid) – polyethylene glycol formulations (PMVEMA-PEG), (25%, 50%, and 75% whiskers) – were investigated using thermal gravimetric analysis (TGA) methods. The thermal degradation behavior of the films varied according to the percent cellulose whiskers in each formulation. The presence of cellulose whiskers increased the thermal stability of the PMVEMA-PEG matrix.

scholarly journals In Situ exploration of the giant planets

2021 ◽  
Author(s):  
O. Mousis ◽  
D. H. Atkinson ◽  
R. Ambrosi ◽  
S. Atreya ◽  
D. Banfield ◽  
...  
Keyword(s):  
Solar System ◽  
Giant Planets ◽  
Atmospheric Composition ◽  
Formation History ◽  
History Of ◽  
Composition Structure ◽  
Galileo Probe ◽  
Probe Measurements

AbstractRemote sensing observations suffer significant limitations when used to study the bulk atmospheric composition of the giant planets of our Solar System. This impacts our knowledge of the formation of these planets and the physics of their atmospheres. A remarkable example of the superiority of in situ probe measurements was illustrated by the exploration of Jupiter, where key measurements such as the determination of the noble gases’ abundances and the precise measurement of the helium mixing ratio were only made available through in situ measurements by the Galileo probe. Here we describe the main scientific goals to be addressed by the future in situ exploration of Saturn, Uranus, and Neptune, placing the Galileo probe exploration of Jupiter in a broader context. An atmospheric entry probe targeting the 10-bar level would yield insight into two broad themes: i) the formation history of the giant planets and that of the Solar System, and ii) the processes at play in planetary atmospheres. The probe would descend under parachute to measure composition, structure, and dynamics, with data returned to Earth using a Carrier Relay Spacecraft as a relay station. An atmospheric probe could represent a significant ESA contribution to a future NASA New Frontiers or flagship mission to be launched toward Saturn, Uranus, and/or Neptune.

scholarly journals Social Tipping Interventions Can Promote the Diffusion or Decay of Sustainable Consumption Norms in the Field. Evidence from a Quasi-Experimental Intervention Study

2021 ◽  
Vol 13 (6) ◽  
pp. 3529
Author(s):  
Joël Berger
Keyword(s):  
Laboratory Experiments ◽  
Sustainable Consumption ◽  
Environmentally Sustainable ◽  
Carbon Neutrality ◽  
Consumption Decisions ◽  
Policy Tool ◽  
Field Evidence ◽  
Current Prevalence ◽  
Quasi Experimental ◽  
Recent Laboratory

The diffusion of environmentally sustainable consumption patterns is crucial for reaching net carbon neutrality. As a promising policy tool for reaching this goal, scholars have put forward social tipping interventions (SOTIs). “Social tipping” refers to the phenomenon that a small initial change in a parameter of a social system can create abrupt, nonlinear change via self-reinforcing feedback. If this reduces the burden on the environment, it is of potential interest for environmental policy. SOTIs are attempts to create social tipping intentionally. SOTIs produce rapid norm changes in laboratory experiments. However, little is known about the potential of SOTIs in the field. This research reports on a field intervention promoting the consumption of hot beverages in reusable mugs instead of one-way cups, conducted at Swiss university cafeterias (N = 162,523 consumption decisions). Two SOTIs involved an appeal promoting sustainable consumption with regular feedback about the current prevalence of sustainable consumption. Two control treatments involved either the same appeal without feedback or no intervention. This research offers three key findings. First, SOTIs involving regular normative feedback can transform sustainable consumption from a minority behavior into a social norm within weeks. Second, tipping points in real-world environmental dilemmas may exceed the values found in recent laboratory experiments (≥50% vs. ≥25%). Third, SOTIs can also promote the decay of sustainable consumption. By implication, the risk-free use of SOTIs requires deeper insights into the boundary conditions of these dynamics.

scholarly journals Listener-Position and Orientation Dependency of Auditory Perception in an Enclosed Space: Elicitation of Salient Attributes

2021 ◽  
Vol 11 (4) ◽  
pp. 1570
Author(s):  
Bogdan Ioan Băcilă ◽  
Hyunkook Lee
Keyword(s):  
Auditory Perception ◽  
Laboratory Experiments ◽  
Head Orientation ◽  
Repertory Grid Technique ◽  
Apparent Source ◽  
Grid Technique ◽  
Subjective Study ◽  
Enclosed Space ◽  
Orientation Dependency

This paper presents a subjective study conducted on the perception of auditory attributes depending on listener position and head orientation in an enclosed space. Two elicitation experiments were carried out using the repertory grid technique—in-situ and laboratory experiments—which aimed to identify perceptual attributes among 10 different combinations of the listener’s positions and head orientations in a concert hall. It was found that, between the in-situ and laboratory experiments, the listening positions and head orientations were clustered identically. Ten salient perceptual attributes were identified from the data obtained from the laboratory experiment. Whilst these included conventional attributes such as ASW (apparent source width) and LEV (listener envelopment), new attributes such as PRL (perceived reverb loudness), ARW (apparent reverb width) and Reverb Direction were identified, and they are hypothesised to be sub-attributes of LEV (listener envelopment). Timbral characteristics such as Reverb Brightness and Echo Brightness were also identified as salient attributes, which are considered to potentially contribute to the overall perceived clarity.

scholarly journals Natural dimethyl sulfide gradients would lead marine predators to higher prey biomass

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Kylie Owen ◽  
Kentaro Saeki ◽  
Joseph D. Warren ◽  
Alessandro Bocconcelli ◽  
David N. Wiley ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Dimethyl Sulfide ◽  
Zooplankton Biomass ◽  
Foraging Success ◽  
Spatially Correlated ◽  
Prey Biomass ◽  
Marine Predators ◽  
Predator Foraging ◽  
The Impact

AbstractFinding prey is essential to survival, with marine predators hypothesised to track chemicals such as dimethyl sulfide (DMS) while foraging. Many predators are attracted to artificially released DMS, and laboratory experiments have shown that zooplankton grazing on phytoplankton accelerates DMS release. However, whether natural DMS concentrations are useful for predators and correlated to areas of high prey biomass remains a fundamental knowledge gap. Here, we used concurrent hydroacoustic surveys and in situ DMS measurements to present evidence that zooplankton biomass is spatially correlated to natural DMS concentration in air and seawater. Using agent simulations, we also show that following gradients of DMS would lead zooplankton predators to areas of higher prey biomass than swimming randomly. Further understanding of the conditions and scales over which these gradients occur, and how they are used by predators, is essential to predicting the impact of future changes in the ocean on predator foraging success.

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