scholarly journals Seasonal cycles and variability of O<sub>3</sub> and H<sub>2</sub>O in the UT/LMS during SPURT

2006 ◽  
Vol 6 (1) ◽  
pp. 109-125 ◽  
Author(s):  
M. Krebsbach ◽  
C. Schiller ◽  
D. Brunner ◽  
G. Günther ◽  
M. I. Hegglin ◽  
...  
Keyword(s):  
Trace Gases ◽  
Distribution Functions ◽  
Trace Gas ◽  
Large Set ◽  
Transport Barrier ◽  
Tropical Tropopause ◽  
Time Period ◽  
Data Coverage ◽  
Insight Into

Abstract. Airborne high resolution in situ measurements of a large set of trace gases including ozone (O3) and total water (H2O) in the upper troposphere and the lowermost stratosphere (UT/LMS) have been performed above Europe within the SPURT project. SPURT provides an extensive data coverage of the UT/LMS in each season within the time period between November 2001 and July 2003. In the LMS a distinct spring maximum and autumn minimum is observed in O3, whereas its annual cycle in the UT is shifted by 2–3 months later towards the end of the year. The more variable H2O measurements reveal a maximum during summer and a minimum during autumn/winter with no phase shift between the two atmospheric compartments. For a comprehensive insight into trace gas composition and variability in the UT/LMS several statistical methods are applied using chemical, thermal and dynamical vertical coordinates. In particular, 2-dimensional probability distribution functions serve as a tool to transform localised aircraft data to a more comprehensive view of the probed atmospheric region. It appears that both trace gases, O3 and H2O, reveal the most compact arrangement and are best correlated in the view of potential vorticity (PV) and distance to the local tropopause, indicating an advanced mixing state on these surfaces. Thus, strong gradients of PV seem to act as a transport barrier both in the vertical and the horizontal direction. The alignment of trace gas isopleths reflects the existence of a year-round extra-tropical tropopause transition layer. The SPURT measurements reveal that this layer is mainly affected by stratospheric air during winter/spring and by tropospheric air during autumn/summer. Normalised mixing entropy values for O3 and H2O in the LMS appear to be maximal during spring and summer, respectively, indicating highest variability of these trace gases during the respective seasons.

scholarly journals Seasonal cycles and variability of O<sub>3</sub> and H<sub>2</sub>O in the UT/LMS during SPURT

2005 ◽  
Vol 5 (4) ◽  
pp. 7247-7282
Author(s):  
M. Krebsbach ◽  
C. Schiller ◽  
D. Brunner ◽  
G. Günther ◽  
M. I. Hegglin ◽  
...  
Keyword(s):  
Trace Gases ◽  
Distribution Functions ◽  
Trace Gas ◽  
Large Set ◽  
Transport Barrier ◽  
Mixing Ratios ◽  
Tropical Tropopause ◽  
Time Period ◽  
Data Coverage

Abstract. Airborne high resolution in situ measurements of a large set of trace gases including ozone (O3) and total water (H2O) in the upper troposphere and the lowermost stratosphere (UT/LMS) have been performed above Europe within the SPURT project. With its innovative campaign concept, SPURT provides an extensive data coverage of the UT/LMS in each season within the time period between November 2001 and July 2003. Ozone volume mixing ratios in the LMS show a distinct spring maximum and autumn minimum, whereas the O3 seasonal cycle in the UT is shifted by 2 to 3 month later towards the end of the year. The more variable H2O measurements reveal a maximum during spring/summer and a minimum during autumn/winter with no phase shift between the two atmospheric compartments. For a comprehensive insight into trace gas composition and variability in the UT/LMS several statistical methods are applied using chemical, thermal and dynamical vertical coordinates. In particular, 2-dimensional probability distribution functions serve as a tool to transform localised aircraft data to a more comprehensive view of the probed atmospheric region. It appears that both trace gases, O3 and H2O, reveal the most compact arrangement and are best correlated in the view of potential vorticity (PV) and distance to the local tropopause, indicating an advanced mixing state on these surfaces. Thus, strong gradients of PV seem to act as a transport barrier both in the vertical and the horizontal direction. The alignment of trace gas isopleths reflects the existence of a year-round extra-tropical tropopause transition layer. The SPURT measurements reveal that this layer is mainly affected by stratospheric air during winter/spring and by tropospheric air during autumn/summer. Mixing entropy values for O3 and H2O in the LMS appear to be maximal during spring and summer, respectively, indicating highest variability of these trace gases during the respective seasons.

Age of Air in the Stratosphere from Observations

2020 ◽  
Author(s):  
Marianna Linz ◽  
Benjamin Birner ◽  
Alan Plumb ◽  
Edwin Gerber ◽  
Florian Haenel ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Nitrous Oxide ◽  
Sulfur Hexafluoride ◽  
Trace Gases ◽  
Trace Gas ◽  
Calculation Methods ◽  
Stratospheric Circulation ◽  
Tracer Age ◽  
Compact Relationship

&lt;p&gt;Age of air is an idealized tracer often used as a measure of the stratospheric circulation. We will show how to quantitatively relate age to the diabatic circulation and the adiabatic mixing. As it is an idealized tracer, age cannot be measured itself and must be inferred from other tracers. Typically, the two primary trace gases used are sulfur hexafluoride and carbon dioxide. Other tracers have a compact relationship with age, however, and can also be used to calculate age. We will discuss a range of tracer measurements from both satellites and in situ, including sulfur hexafluoride, carbon dioxide, nitrous oxide, methane, and the ratio of argon to nitrogen. We will compare the age derived from these different species, including different calculation methods and caveats, and compare with modeled ideal age and trace gas concentrations. We conclude by showing the strength of the diabatic circulation and the adiabatic mixing calculated from these trace gas calculations.&lt;/p&gt;

Cross-isentropic mixing: A DEEPWAVE case study

2020 ◽  
Author(s):  
Hans-Christoph Lachnitt ◽  
Peter Hoor ◽  
Daniel Kunkel ◽  
Stafan Hofmann ◽  
Martina Bramberger ◽  
...  
Keyword(s):  
Gravity Wave ◽  
Trace Gases ◽  
Measurement Data ◽  
Wave Activity ◽  
Southern Alps ◽  
Trace Gas ◽  
Leeward Side ◽  
Mixing Processes ◽  
Stability Parameters

&lt;p&gt;The tropopause acts as a transport barrier between the upper troposphere and the lower stratosphere. Non-conservative (i.e. PV changing) processes are required to overcome this barrier. Orographically generated gravity waves (i.e. mountain waves) can potentially lead to cross-isentropic fluxes of trace gases via the generation of turbulence. Thus they may alter the isentropic gradient of these trace species across the tropopause.&lt;br&gt;The specific goal of this study is to identify cross-isentropic mixing processes at the tropopause based on the distribution of trace gases (i.e. tracer-tracer correlations). Based on airborne in-situ trace gas measurements of CO and N&lt;sub&gt;2&lt;/sub&gt;O during the DEEPWAVE (Deep Propagating Gravity Wave Experiment) campaign in July 2014 we identified mixing regions above the Southern Alps during periods of gravity wave activity. These in-situ data show that the composition of the air above the Southern Alps change from the upstream to the leeward side of the mountains indicating cross isentropic mixing of trace gases in the region of gravity wave activity.&lt;br&gt;We complement our analysis of the measurement data with high resolution operational analysis data from the ECMWF (European Centre for Medium-Range Weather Forecasts). Furthermore, using potential vorticity and stability parameters.&lt;br&gt;Using 3D wind fields, data form Graphical Turbulence Guidance (GTG) system and in-situ measurements of the vertical wind we identify occurrence of turbulence in the region of mixing events. Using wavelet analysis, we could identify the spatial and temporal scales of local trace gas fluxes. We also give estimates of cross-isentropic flux, i.e. we want to quantify the mixing in terms of exchange.&lt;/p&gt;

scholarly journals Seasonality and extent of extratropical TST derived from in-situ CO measurements during SPURT

2004 ◽  
Vol 4 (5) ◽  
pp. 1427-1442 ◽  
Author(s):  
P. Hoor ◽  
C. Gurk ◽  
D. Brunner ◽  
M. I. Hegglin ◽  
H. Wernli ◽  
...  
Keyword(s):  
Potential Temperature ◽  
Mixing Layer ◽  
Trace Gas ◽  
Tropical Tropopause ◽  
Tropopause Region ◽  
Gas Measurements ◽  
Transport And Mixing ◽  
Extratropical Tropopause ◽  
Background Air

Abstract. We present airborne in-situ trace gas measurements which were performed on eight campaigns between November 2001 and July 2003 during the SPURT-project (SPURenstofftransport in der Tropopausenregion, trace gas transport in the tropopause region). The measurements on a quasi regular basis allowed an overview of the seasonal variations of the trace gas distribution in the tropopause region over Europe from 35°-75°N to investigate the influence of transport and mixing across the extratropical tropopause on the lowermost stratosphere. From the correlation of CO and O3 irreversible mixing of tropospheric air into the lowermost stratosphere is identified. The CO distribution indicates that transport and subsequent mixing of tropospheric air across the extratropical tropopause predominantly affects a layer, which closely follows the shape of the local tropopause. In addition, the seasonal cycle of CO2 illustrates the strong coupling of that layer to the extratropical troposphere. Both, horizontal gradients of CO on isentropes as well as the CO-O3-distribution in the lowermost stratosphere reveal that the influence of quasi-horizontal transport and subsequent mixing weakens with distance from the local tropopause. The mixing layer extends to about 25 K in potential temperature above the local tropopause exhibiting only a weak seasonality. However, at large distances from the tropopause a significant influence of tropospheric air is still evident. The relation between N2O and CO2 indicates that a significant contribution of air originating from the tropical tropopause contributes to the background air in the extratropical lowermost stratosphere.

scholarly journals Statistical analysis of water vapour and ozone in the UT/LS observed during SPURT and MOZAIC

2008 ◽  
Vol 8 (22) ◽  
pp. 6603-6615 ◽  
Author(s):  
A. Kunz ◽  
C. Schiller ◽  
F. Rohrer ◽  
H. G. J. Smit ◽  
P. Nedelec ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Water Vapour ◽  
Trace Gases ◽  
Distribution Functions ◽  
Variance Analysis ◽  
Trace Gas ◽  
Data Sets ◽  
Data Set ◽  
Atmospheric Processes ◽  
Passenger Aircraft

Abstract. A statistical analysis for the comparability of water (H2O) and ozone (O3) data sets sampled during the SPURT aircraft campaigns and the MOZAIC passenger aircraft flights is presented. The Kolmogoroff-Smirnoff test reveals that the distribution functions from SPURT and MOZAIC trace gases differ from each other with a confidence of 95%. A variance analysis shows a different variability character in both trace gas data sets. While the SPURT H2O data only contain atmospheric processes variable on a diurnal or synoptical timescale, MOZAIC H2O data also reveal processes, which vary on inter-seasonal and seasonal timescales. The SPURT H2O data set does not represent the full MOZAIC H2O variance in the UT/LS for climatological investigations, whereas the variance of O3 is much better represented. SPURT H2O data are better suited in the stratosphere, where the MOZAIC RH sensor looses its sensitivity.

scholarly journals Seasonality and extent of extratropical TST derived from in-situ CO measurements during SPURT

2004 ◽  
Vol 4 (2) ◽  
pp. 1691-1726 ◽  
Author(s):  
P. Hoor ◽  
C. Gurk ◽  
D. Brunner ◽  
M. I. Hegglin ◽  
H. Wernli ◽  
...  
Keyword(s):  
Significant Contribution ◽  
Trace Gas ◽  
Horizontal Gradients ◽  
Tropical Tropopause ◽  
Tropopause Region ◽  
Gas Measurements ◽  
Transport And Mixing ◽  
Extratropical Tropopause ◽  
Background Air

Abstract. We present airborne in-situ trace gas measurements which were performed on eight campaigns between November 2001 and July 2003 during the SPURT-project (SPURenstofftransport in der Tropopausenregion, trace gas transport in the tropopause region). The measurements on a quasi regular basis allowed an overview on the seasonal variations of the trace gas distribution in the tropopause region over Europe from 35°–75° N to investigate the influence of transport and mixing across the extratropical tropopause on the lowermost stratosphere. From the correlation of CO and O3 irreversible mixing of tropospheric air into the lowermost stratosphere is identified. The CO distribution indicates that transport and subsequent mixing of tropospheric air across the extratropical tropopause predominantely affects a layer, which closely follows the shape of the local tropopause. In addition the seasonal cycle of CO2 illustrates the strong coupling of that layer to the extratropical troposphere. Both, horizontal gradients of CO on isentropes as well as the CO-O3-distribution in the lowermost stratosphere reveal that the influence of quasi-horizontal transport and subsequent mixing weakens with distance from the local tropopause. However, at large distances from the tropopause a significant influence of tropospheric air is still evident. The relation between N2O and CO2 indicates that a significant contribution of air originating from the tropical tropopause contributes to the background air in the extratropical lowermost stratosphere.

scholarly journals Diagnostics of the Tropical Tropopause Layer from in-situ observations and CCM data

2009 ◽  
Vol 9 (3) ◽  
pp. 11659-11698
Author(s):  
E. Palazzi ◽  
F. Fierli ◽  
F. Cairo ◽  
C. Cagnazzo ◽  
G. Di Donfrancesco ◽  
...  
Keyword(s):  
Vertical Structure ◽  
Climate Model ◽  
Joint Analysis ◽  
Vertical Profiles ◽  
Transport Barrier ◽  
Tropical Tropopause Layer ◽  
Mixing Ratios ◽  
Tropical Tropopause ◽  
Scatter Plots

Abstract. A suite of diagnostics is applied to in-situ aircraft measurements and one Chemistry-Climate Model (CCM) data to characterize the vertical structure of the Tropical Tropopause Layer (TTL). The diagnostics are based on the vertical tracers profiles, relative vertical tracers gradients, and tracer-tracer relationships in the tropical Upper Troposphere/Lower Stratosphere (UT/LS), using tropopause coordinates. Observations come from the four tropical campaigns performed from 1998 to 2006 with the research aircraft Geophysica and have been directly compared to the output of the ECHAM5/MESSy CCM. The model vertical resolution in the TTL allows for appropriate comparison with high-resolution aircraft observations and the diagnostics used highlight common TTL features between the model and the observational data. The analysis of the vertical profiles of water vapour, ozone, and nitrous oxide, in both the observations and the model, shows that concentration mixing ratios exhibit a strong gradient change across the tropical tropopause, due to the role of this latter as a transport barrier and that transition between the tropospheric and stratospheric regimes occurs within a finite layer. The use of relative vertical ozone gradients, in addition to the vertical profiles, helps to highlight the region where this transition occurs and allows to give an estimate of its thickness. The analysis of the CO-O3 and H2O-O3 scatter plots and of the Probability Distribution Function (PDF) of the H2O-O3 pair completes this picture as it allows to better distinguish tropospheric and stratospheric regimes that can be identified, first, by their differing chemical composition. The joint analysis and comparison of observed and modelled data allows us to evaluate the capability of the model in reproducing the observed vertical structure of the TTL and its variability, and also to assess whether observations from particular regions on a monthly timescale can be representative of the fine scale mean structure of the Tropical Tropopause Layer.

scholarly journals Measurement report: Photochemical production and loss rates of formaldehyde and ozone across Europe

2021 ◽  
Author(s):  
Clara M. Nussbaumer ◽  
John N. Crowley ◽  
Jan Schuladen ◽  
Jonathan Williams ◽  
Sascha Hafermann ◽  
...  
Keyword(s):  
Trace Gases ◽  
Ozone Production ◽  
Trace Gas ◽  
Coastal Site ◽  
Sources And Sinks ◽  
Oxidation Of Methane ◽  
Mountain Site ◽  
In Situ Observations ◽  
Summer Time

Abstract. Various atmospheric sources and sinks regulate the abundance of tropospheric formaldehyde (HCHO) which is an important trace gas impacting the HOx (≡ HO2 + OH) budget and the concentration of ozone (O3). In this study, we present the formation and destruction terms of ambient HCHO and O3 calculated from in-situ observations of various atmospheric trace gases measured at three different sites across Europe during summer time. These include a coastal site in Cyprus in the scope of the Cyprus Photochemistry Experiment (CYPHEX) in 2014, a mountain site in Southern Germany as part of the Hohenpeißenberg Photochemistry Experiment (HOPE) in 2012 and a forested site in Finland where measurements were performed during the Hyytiälä United Measurements of Photochemistry and Particles (HUMPPA) campaign in 2010. We show that at all three sites formaldehyde production from the OH oxidation of methane (CH4), acetaldehyde (CH3CHO), isoprene (C5H8) and methanol (CH3OH) can almost completely balance the observed loss via photolysis, OH oxidation and dry deposition. Ozone chemistry is clearly controlled by nitrogen oxides (NOx ≡ NO + NO2) that includes O3 production from NO2 photolysis and O3 loss via the reaction with NO. Finally, we use the HCHO budget calculations to determine whether net ozone production is limited by the availability of VOCs (VOC limited regime) or NOx (NOx limited regime). At the mountain site in Germany O3 production is VOC limited, whereas it is NOx limited at the coastal site in Cyprus. The forested site in Finland is in the transition regime.

scholarly journals Versatile soil gas concentration and isotope monitoring: optimization and integration of novel soil gas probes with online trace gas detection

2022 ◽  
Vol 19 (1) ◽  
pp. 165-185
Author(s):  
Juliana Gil-Loaiza ◽  
Joseph R. Roscioli ◽  
Joanne H. Shorter ◽  
Till H. M. Volkmann ◽  
Wei-Ren Ng ◽  
...  
Keyword(s):  
Real Time ◽  
Trace Gases ◽  
Soil Gas ◽  
Redox Conditions ◽  
Trace Gas ◽  
Soil System ◽  
Isotopic Signatures ◽  
Gas Measurements ◽  
The Impact

Abstract. Gas concentrations and isotopic signatures can unveil microbial metabolisms and their responses to environmental changes in soil. Currently, few methods measure in situ soil trace gases such as the products of nitrogen and carbon cycling or volatile organic compounds (VOCs) that constrain microbial biochemical processes like nitrification, methanogenesis, respiration, and microbial communication. Versatile trace gas sampling systems that integrate soil probes with sensitive trace gas analyzers could fill this gap with in situ soil gas measurements that resolve spatial (centimeters) and temporal (minutes) patterns. We developed a system that integrates new porous and hydrophobic sintered polytetrafluoroethylene (sPTFE) diffusive soil gas probes that non-disruptively collect soil gas samples with a transfer system to direct gas from multiple probes to one or more central gas analyzer(s) such as laser and mass spectrometers. Here, we demonstrate the feasibility and versatility of this automated multiprobe system for soil gas measurements of isotopic ratios of nitrous oxide (δ18O, δ15N, and the 15N site preference of N2O), methane, carbon dioxide (δ13C), and VOCs. First, we used an inert silica matrix to challenge probe measurements under controlled gas conditions. By changing and controlling system flow parameters, including the probe flow rate, we optimized recovery of representative soil gas samples while reducing sampling artifacts on subsurface concentrations. Second, we used this system to provide a real-time window into the impact of environmental manipulation of irrigation and soil redox conditions on in situ N2O and VOC concentrations. Moreover, to reveal the dynamics in the stable isotope ratios of N2O (i.e., 14N14N16O, 14N15N16O, 15N14N16O, and 14N14N18O), we developed a new high-precision laser spectrometer with a reduced sample volume demand. Our integrated system – a tunable infrared laser direct absorption spectrometry (TILDAS) in parallel with Vocus proton transfer reaction mass spectrometry (PTR-MS), in line with sPTFE soil gas probes – successfully quantified isotopic signatures for N2O, CO2, and VOCs in real time as responses to changes in the dry–wetting cycle and redox conditions. Broadening the collection of trace gases that can be monitored in the subsurface is critical for monitoring biogeochemical cycles, ecosystem health, and management practices at scales relevant to the soil system.

scholarly journals Diagnostics of the Tropical Tropopause Layer from in-situ observations and CCM data

2009 ◽  
Vol 9 (24) ◽  
pp. 9349-9367 ◽  
Author(s):  
E. Palazzi ◽  
F. Fierli ◽  
F. Cairo ◽  
C. Cagnazzo ◽  
G. Di Donfrancesco ◽  
...  
Keyword(s):  
Climate Model ◽  
Regional Scale ◽  
Transport Processes ◽  
Joint Analysis ◽  
Vertical Profiles ◽  
Transport Barrier ◽  
Model Estimate ◽  
Tropical Tropopause Layer ◽  
Tropical Tropopause

Abstract. A suite of diagnostics is applied to in-situ aircraft measurements and one Chemistry-Climate Model (CCM) data to characterize the vertical structure of the Tropical Tropopause Layer (TTL). The diagnostics are based on vertical tracer profiles and relative vertical tracer gradients, using tropopause-referenced coordinates, and tracer-tracer relationships in the tropical Upper Troposphere/Lower Stratosphere (UT/LS). Observations were obtained during four tropical campaigns performed from 1999 to 2006 with the research aircraft Geophysica and have been compared to the output of the ECHAM5/MESSy CCM. The model vertical resolution in the TTL (~500 m) allows for appropriate comparison with high-resolution aircraft observations and the diagnostics used highlight common TTL features between the model and the observational data. The analysis of the vertical profiles of water vapour, ozone, and nitrous oxide, in both the observations and the model, shows that concentration mixing ratios exhibit a strong gradient change across the tropical tropopause, due to the role of this latter as a transport barrier and that transition between the tropospheric and stratospheric regimes occurs within a finite layer. The use of relative vertical ozone and carbon monoxide gradients, in addition to the vertical profiles, helps to highlight the region where this transition occurs and allows to give an estimate of its thickness. The analysis of the CO-O3 and H2O-O3 scatter plots and of the Probability Distribution Function (PDF) of the H2O-O3 pair completes this picture as it allows to better distinguish tropospheric and stratospheric regimes that can be identified by their different chemical composition. The joint analysis and comparison of observed and modelled data allows to state that the model can represent the background TTL structure and its seasonal variability rather accurately. The model estimate of the thickness of the interface region between tropospheric and stratospheric regimes agrees well with average values inferred from observations. On the other hand, the measurements can be influenced by regional scale variability, local transport processes as well as deep convection, that can not be captured by the model.

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