scholarly journals First detection of ozone in the mid-infrared at Mars: implications for methane detection

2020 ◽  
Vol 639 ◽  
pp. A141 ◽  
Author(s):  
K. S. Olsen ◽  
F. Lefèvre ◽  
F. Montmessin ◽  
A. Trokhimovskiy ◽  
L. Baggio ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Polar Vortex ◽  
Trace Gas ◽  
Spectral Signature ◽  
Infrared Range ◽  
Mid Infrared ◽  
Northern Latitudes ◽  
Ultraviolet Range ◽  
Vibration Rotation ◽  
Methane Detection

Aims. The ExoMars Trace Gas Orbiter was sent to Mars in March 2016 to search for trace gases diagnostic of active geological or biogenic processes. Methods. We report the first observation of the spectral features of Martian ozone (O3) in the mid-infrared range using the Atmospheric Chemistry Suite Mid-InfaRed (MIR) channel, a cross-dispersion spectrometer operating in solar occultation mode with the finest spectral resolution of any remote sensing mission to Mars. Results. Observations of ozone were made at high northern latitudes (>65°N) prior to the onset of the 2018 global dust storm (Ls = 163–193°). During this fast transition phase between summer and winter ozone distribution, the O3 volume mixing ratio observed is 100–200 ppbv near 20 km. These amounts are consistent with past observations made at the edge of the southern polar vortex in the ultraviolet range. The observed spectral signature of ozone at 3000–3060 cm−1 directly overlaps with the spectral range of the methane (CH4) ν3 vibration-rotation band, and it, along with a newly discovered CO2 band in the same region, may interfere with measurements of methane abundance.

scholarly journals Impact of Lagrangian transport on lower-stratospheric transport timescales in a climate model

2020 ◽  
Vol 20 (23) ◽  
pp. 15227-15245
Author(s):  
Edward J. Charlesworth ◽  
Ann-Kristin Dugstad ◽  
Frauke Fritsch ◽  
Patrick Jöckel ◽  
Felix Plöger
Keyword(s):  
Atmospheric Chemistry ◽  
Large Scale ◽  
Climate Model ◽  
Polar Vortex ◽  
Transport Processes ◽  
Lagrangian Model ◽  
Trace Gas ◽  
Lagrangian Transport ◽  
Transport Barriers ◽  
The Impact

Abstract. We investigate the impact of model trace gas transport schemes on the representation of transport processes in the upper troposphere and lower stratosphere. Towards this end, the Chemical Lagrangian Model of the Stratosphere (CLaMS) was coupled to the ECHAM/MESSy Atmospheric Chemistry (EMAC) model and results from the two transport schemes (Lagrangian critical Lyapunov scheme and flux-form semi-Lagrangian, respectively) were compared. Advection in CLaMS was driven by the EMAC simulation winds, and thereby the only differences in transport between the two sets of results were caused by differences in the transport schemes. To analyze the timescales of large-scale transport, multiple tropical-surface-emitted tracer pulses were performed to calculate age of air spectra, while smaller-scale transport was analyzed via idealized, radioactively decaying tracers emitted in smaller regions (nine grid cells) within the stratosphere. The results show that stratospheric transport barriers are significantly stronger for Lagrangian EMAC-CLaMS transport due to reduced numerical diffusion. In particular, stronger tracer gradients emerge around the polar vortex, at the subtropical jets, and at the edge of the tropical pipe. Inside the polar vortex, the more diffusive EMAC flux-form semi-Lagrangian transport scheme results in a substantially higher amount of air with ages from 0 to 2 years (up to a factor of 5 higher). In the lowermost stratosphere, mean age of air is much smaller in EMAC, owing to stronger diffusive cross-tropopause transport. Conversely, EMAC-CLaMS shows a summertime lowermost stratosphere age inversion – a layer of older air residing below younger air (an “eave”). This pattern is caused by strong poleward transport above the subtropical jet and is entirely blurred by diffusive cross-tropopause transport in EMAC. Potential consequences from the choice of the transport scheme on chemistry–climate and geoengineering simulations are discussed.

scholarly journals Satellite observations and modeling of transport in the upper troposphere through the lower mesosphere during the 2006 major stratospheric sudden warming

2009 ◽  
Vol 9 (14) ◽  
pp. 4775-4795 ◽  
Author(s):  
G. L. Manney ◽  
R. S. Harwood ◽  
I. A. MacKenzie ◽  
K. Minschwaner ◽  
D. R. Allen ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Lower Stratosphere ◽  
Transport Model ◽  
Polar Vortex ◽  
Trace Gas ◽  
Transport Barrier ◽  
Stratospheric Sudden Warming ◽  
Upper Troposphere ◽  
Comprehensive Picture ◽  
Middle Stratosphere

Abstract. An unusually strong and prolonged stratospheric sudden warming (SSW) in January 2006 was the first major SSW for which globally distributed long-lived trace gas data are available covering the upper troposphere through the lower mesosphere. We use Aura Microwave Limb Sounder (MLS), Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS) data, the SLIMCAT Chemistry Transport Model (CTM), and assimilated meteorological analyses to provide a comprehensive picture of transport during this event. The upper tropospheric ridge that triggered the SSW was associated with an elevated tropopause and layering in trace gas profiles in conjunction with stratospheric and tropospheric intrusions. Anomalous poleward transport (with corresponding quasi-isentropic troposphere-to-stratosphere exchange at the lowest levels studied) in the region over the ridge extended well into the lower stratosphere. In the middle and upper stratosphere, the breakdown of the polar vortex transport barrier was seen in a signature of rapid, widespread mixing in trace gases, including CO, H2O, CH4 and N2O. The vortex broke down slightly later and more slowly in the lower than in the middle stratosphere. In the middle and lower stratosphere, small remnants with trace gas values characteristic of the pre-SSW vortex lingered through the weak and slow recovery of the vortex. The upper stratospheric vortex quickly reformed, and, as enhanced diabatic descent set in, CO descended into this strong vortex, echoing the fall vortex development. Trace gas evolution in the SLIMCAT CTM agrees well with that in the satellite trace gas data from the upper troposphere through the middle stratosphere. In the upper stratosphere and lower mesosphere, the SLIMCAT simulation does not capture the strong descent of mesospheric CO and H2O values into the reformed vortex; this poor CTM performance in the upper stratosphere and lower mesosphere results primarily from biases in the diabatic descent in assimilated analyses.

scholarly journals Satellite observations and modelling of transport in the upper troposphere through the lower mesosphere during the 2006 major stratospheric sudden arming

2009 ◽  
Vol 9 (2) ◽  
pp. 9693-9745 ◽  
Author(s):  
G. L. Manney ◽  
R. S. Harwood ◽  
I. A. MacKenzie ◽  
K. Minschwaner ◽  
D. R. Allen ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Lower Stratosphere ◽  
Transport Model ◽  
Polar Vortex ◽  
Trace Gas ◽  
Transport Barrier ◽  
Upper Troposphere ◽  
Comprehensive Picture ◽  
Ch4 And N2o ◽  
Middle Stratosphere

Abstract. An unusually strong and prolonged stratospheric sudden warming (SSW) in January 2006 was the first major SSW for which globally distributed long-lived trace gas data are available covering the upper troposphere through the lower mesosphere. We use Aura Microwave Limb Sounder (MLS), Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS) data, the SLIMCAT Chemistry Transport Model (CTM), and assimilated meteorological analyses to provide a comprehensive picture of transport during this event. The upper tropospheric ridge that triggered the SSW was associated with an elevated tropopause and layering in trace gas profiles in conjunction with stratospheric and tropospheric intrusions. Anomalous poleward transport (with corresponding quasi-isentropic troposphere-to-stratosphere exchange at the lowest levels studied) in the region over the ridge extended well into the lower stratosphere. In the middle and upper stratosphere, the breakdown of the polar vortex transport barrier was seen in a signature of rapid, widespread mixing in trace gases, including CO, H2O, CH4 and N2O. The vortex broke down slightly later and more slowly in the lower than in the middle stratosphere. In the middle and lower stratosphere, small remnants with trace gas values characteristic of the pre-SSW vortex lingered through the weak and slow recovery of the vortex. The upper stratospheric vortex quickly reformed, and, as enhanced diabatic descent set in, CO descended into this strong vortex, echoing the fall vortex development. Trace gas evolution in the SLIMCAT CTM agrees well with that in the satellite trace gas data from the upper troposphere through the middle stratosphere. In the upper stratosphere and lower mesosphere, the SLIMCAT simulation does not capture the strong descent of mesospheric CO and H2O values into the reformed vortex; poor CTM performance in the upper stratosphere and lower mesosphere results primarily from biases in the diabatic descent in assimilated analyses.

A Mid-Infrared Dual-Comb Spectrometer for High Sensitivity Multi-Component Trace Gas Detection

2020 ◽  
Author(s):  
Leonard Nitzsche ◽  
Jens Goldschmidt ◽  
Jens Kießling ◽  
Sebastian Wolf ◽  
Frank Kühnemann ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Gas Detection ◽  
Trace Gas ◽  
Trace Gas Detection ◽  
Mid Infrared

Relationship of the drying process of a corn grain with the thermal emissivity and optical interference in the mid infrared range

2017 ◽  
Vol 56 (12) ◽  
pp. 3470
Author(s):  
Carlos Villaseñor-Mora ◽  
Francisco J. Gantes-Nunez ◽  
Arturo Gonzalez-Vega ◽  
Victor H. Hernandez-Gonzalez
Keyword(s):  
Infrared Range ◽  
Drying Process ◽  
Optical Interference ◽  
Mid Infrared ◽  
Thermal Emissivity ◽  
Relationship Of ◽  
Corn Grain

scholarly journals Case studies of the impact of orbital sampling on stratospheric trend detection and derivation of tropical vertical velocities: solar occultation vs. limb emission sounding

2016 ◽  
Vol 16 (18) ◽  
pp. 11521-11534 ◽  
Author(s):  
Luis F. Millán ◽  
Nathaniel J. Livesey ◽  
Michelle L. Santee ◽  
Jessica L. Neu ◽  
Gloria L. Manney ◽  
...  
Keyword(s):  
Case Studies ◽  
Atmospheric Chemistry ◽  
Stratospheric Ozone ◽  
Sampling Bias ◽  
Nonuniform Sampling ◽  
Trend Detection ◽  
Trace Gas ◽  
Uniform Sampling ◽  
Solar Occultation ◽  
The Impact

Abstract. This study investigates the representativeness of two types of orbital sampling applied to stratospheric temperature and trace gas fields. Model fields are sampled using real sampling patterns from the Aura Microwave Limb Sounder (MLS), the HALogen Occultation Experiment (HALOE) and the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS). The MLS sampling acts as a proxy for a dense uniform sampling pattern typical of limb emission sounders, while HALOE and ACE-FTS represent coarse nonuniform sampling patterns characteristic of solar occultation instruments. First, this study revisits the impact of sampling patterns in terms of the sampling bias, as previous studies have done. Then, it quantifies the impact of different sampling patterns on the estimation of trends and their associated detectability. In general, we find that coarse nonuniform sampling patterns may introduce non-negligible errors in the inferred magnitude of temperature and trace gas trends and necessitate considerably longer records for their definitive detection. Lastly, we explore the impact of these sampling patterns on tropical vertical velocities derived from stratospheric water vapor measurements. We find that coarse nonuniform sampling may lead to a biased depiction of the tropical vertical velocities and, hence, to a biased estimation of the impact of the mechanisms that modulate these velocities. These case studies suggest that dense uniform sampling such as that available from limb emission sounders provides much greater fidelity in detecting signals of stratospheric change (for example, fingerprints of greenhouse gas warming and stratospheric ozone recovery) than coarse nonuniform sampling such as that of solar occultation instruments.

scholarly journals Dynamics and composition of the Asian summer monsoon anticyclone

2017 ◽  
Author(s):  
Klaus-Dirk Gottschaldt ◽  
Hans Schlager ◽  
Robert Baumann ◽  
Duy S. Cai ◽  
Veronika Eyring ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
Atmospheric Chemistry ◽  
Asian Summer Monsoon ◽  
Monsoon Season ◽  
Lower Troposphere ◽  
Equatorial Region ◽  
Ozone Production ◽  
Trace Gas ◽  
Asian Summer ◽  
Southern Fringe

Abstract. This study places HALO research aircraft observations in the upper-tropospheric Asian summer monsoon anticyclone (ASMA) obtained during the Earth System Model Validation (ESMVal) campaign in September 2012 into the context of regional, intra-annual variability by hindcasts with the ECHAM/MESSy Atmospheric Chemistry (EMAC) model. The simulations demonstrate that tropospheric trace gas profiles in the monsoon season are distinct from the rest of the year. Air uplifted from the lower troposphere to the tropopause layer dominates the eastern part of the ASMA’s interior, while the western part is characterised by subsidence down to the mid-troposphere. Soluble compounds are being washed out when uplifted by convection in the eastern part, where lightning simultaneously replenishes reactive nitrogen in the upper troposphere. Net photochemical ozone production is significantly enhanced in the ASMA, contrasted by an ozone depleting regime in the mid-troposphere and more neutral conditions in autumn and winter. An analysis of multiple monsoon seasons in the simulation shows that stratospherically influenced tropopause layer air is regularly entrained at the eastern ASMA flank, and then transported in the southern fringe around the interior region. Observed and simulated tracer-tracer relations reflect photochemical O3 production, as well as in-mixing from the lower troposphere and the tropopause layer. The simulation additionally shows entrainment of clean air from the equatorial region by northerly winds at the western ASMA flank. Although the in situ measurements were performed towards the end of summer, the main ingredients needed for their interpretation are present throughout the monsoon season. A transition between two dynamical modes of the ASMA took place during the HALO ESMVal campaign. Transport barriers of the original anticyclone are overcome effectively when it splits up. Air from the fringe is stirred into the interiors of the new anticyclones and vice versa. Instabilities of this and other types occur quite frequently. Our study emphasises their paramountcy for the trace gas composition of the ASMA and its outflow into regions around the world.

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