Modelling the reversible uptake of chemical species in the gas phase by ice particles formed in a convective cloud

Abstract. The present paper is a preliminary study preparing the introduction of reversible trace gas uptake by ice particles into a 3-D cloud resolving model. For this a 3-D simulation of a tropical deep convection cloud was run with the BRAMS cloud resolving model using a two-moment bulk microphysical parameterization. Trajectories encountering the convective clouds were computed from these simulation outputs along which the variations of the pristine ice, snow and aggregate mixing ratios and size distributions were extracted. The reversible uptake of 11 trace gases by ice was examined assuming applicability of Langmuir isotherms using recently evaluated (IUPAC) laboratory data. The results show that ice uptake is only significant for HNO3, HCl, CH3COOH and HCOOH. For H2O2, using new results for the partition coefficient results in significant partitioning to the ice phase for this trace gas also. It was also shown that the uptake is largely dependent on the temperature for some species. The adsorption saturation at the ice surface for large gas concentrations is generally not a limiting factor except for HNO3 and HCl for gas concentration greater than 1 ppbv. For HNO3, results were also obtained using a trapping theory, resulting in a similar order of magnitude of uptake, although the two approaches are based on different assumptions. The results were compared to those obtained using a BRAMS cloud simulation based on a single-moment microphysical scheme instead of the two moment scheme. We found similar results with a slightly more important uptake when using the single-moment scheme which is related to slightly higher ice mixing ratios in this simulation. The way to introduce these results in the 3-D cloud model is discussed.

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Modelling the reversible uptake of chemical species in the gas phase by ice particles formed in a convective cloud

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-4977-2010 ◽

2010 ◽

Vol 10 (10) ◽

pp. 4977-5000 ◽

Cited By ~ 22

Author(s):

V. Marécal ◽

M. Pirre ◽

E. D. Rivière ◽

N. Pouvesle ◽

J. N. Crowley ◽

...

Keyword(s):

Cloud Model ◽

Laboratory Data ◽

Chemical Species ◽

Trace Gas ◽

Limiting Factor ◽

Gas Mixing ◽

Mixing Ratios ◽

Ice Particles ◽

Cloud Resolving Model ◽

Single Moment

Abstract. The present paper is a preliminary study preparing the introduction of reversible trace gas uptake by ice particles into a 3-D cloud resolving model. For this a 3-D simulation of a tropical deep convection cloud was run with the BRAMS cloud resolving model using a two-moment bulk microphysical parameterization. Trajectories within the convective clouds were computed from these simulation outputs along which the variations of the pristine ice, snow and aggregate mixing ratios and concentrations were extracted. The reversible uptake of 11 trace gases by ice was examined assuming applicability of Langmuir isotherms using recently evaluated (IUPAC) laboratory data. The results show that ice uptake is only significant for HNO3, HCl, CH3COOH and HCOOH. For H2O2, using new results for the partition coefficient results in significant partitioning to the ice phase for this trace gas also. It was also shown that the uptake is largely dependent on the temperature for some species. The adsorption saturation at the ice surface for large gas mixing ratios is generally not a limiting factor except for HNO3 and HCl for gas mixing ratio greater than 1 ppbv. For HNO3, results were also obtained using a trapping theory, resulting in a similar order of magnitude of uptake, although the two approaches are based on different assumptions. The results were compared to those obtained using a BRAMS cloud simulation based on a single-moment microphysical scheme instead of the two moment scheme. We found similar results with a slightly more important uptake when using the single-moment scheme which is related to slightly higher ice mixing ratios in this simulation. The way to introduce these results in the 3-D cloud model is discussed.

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Modeling Study of Ice Formation in Warm-Based Precipitating Shallow Cumulus Clouds

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-11-0344.1 ◽

2012 ◽

Vol 69 (11) ◽

pp. 3315-3335 ◽

Cited By ~ 14

Author(s):

Jiming Sun ◽

Parisa A. Ariya ◽

Henry G. Leighton ◽

Man Kong Yau

Keyword(s):

Cloud Model ◽

Cloud Condensation Nuclei ◽

Interaction Model ◽

Convective Cloud ◽

Liquid Droplets ◽

Condensation Nuclei ◽

Cumulus Clouds ◽

Ice Nuclei ◽

Shallow Cumulus ◽

Ice Particles

Abstract Observations of large concentrations of ice particles in the dissipating stage of warm-based precipitating shallow cumulus clouds point to the limitations of scientists’ understanding of the physics of such clouds and the possible role of cloud dynamics. The most commonly accepted mechanisms of ice splinter production in the riming process have limitations to properly explain the rapid production of ice bursts. A more detailed description of the temporal and spatial evolution of hydrometeors and their interaction with cloud condensation nuclei and ice nuclei is needed to understand this phenomenon. A cloud model with bin-resolved microphysics can describe the time-dependent evolution of liquid droplets and ice particles and provide insights into how the physics and dynamics and their interaction may result in ice initiation and ice multiplication. The authors developed a 1.5-dimensional nonhydrostatic convective cloud and aerosol interaction model with spectral (bin) microphysics. The number and mass concentrations of aerosols, including ice nuclei and cloud condensation nuclei, were explicitly followed. Since both in situ observations of bioaerosols and laboratory experiments pointed to efficient nucleation capabilities at relative warm temperatures, it was assumed that ice-nucleating bioaerosols are involved in primary ice particle formation in condensation and immersion modes. Results show that bioaerosols can be the source of primary ice pellets, which in turn lead to high ice concentrations.

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Explicit simulation of aerosol physics in a cloud-resolving model

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-4-753-2004 ◽

2004 ◽

Vol 4 (1) ◽

pp. 753-803 ◽

Cited By ~ 2

Author(s):

A. M. L. Ekman ◽

C. Wang ◽

J. Wilson ◽

J. Ström

Keyword(s):

Chemical Species ◽

Convective Cloud ◽

Substantial Part ◽

Cloud Droplets ◽

Upper Troposphere ◽

Aerosol Mass ◽

Cloud Resolving Model ◽

Long Time ◽

Nucleation Scavenging ◽

Aitken Mode

Abstract. The role of convection in introducing aerosols and promoting the formation of new particles to the upper troposphere has been examined using a cloud-resolving model coupled with an interactive explicit aerosol module. A baseline simulation suggests good agreement in the upper troposphere between modeled and observed results including concentrations of aerosols in different size ranges, mole fractions of key chemical species, and concentrations of ice particles. In addition, a set of 34 sensitivity simulations has been carried out to investigate the sensitivity of modeled results to the treatment of various aerosol physical and chemical processes in the model. The size distribution of aerosols is proved to be an important factor in determining the aerosols' fate within the convective cloud. Nucleation mode aerosols (0<−d<−5.84 nm) are quickly transferred to the larger modes as they grow through coagulation and condensation of H2SO4. Accumulation mode aerosols (d>−31.0 nm) are almost completely removed by nucleation (activation of cloud droplets) and impact scavenging. However, a substantial part (up to 10% of the boundary layer concentration) of the Aitken mode aerosol population (5.84 nm<−d<−31.0 nm) reaches the top of the cloud and the free troposphere. These particles may continually survive in the upper troposphere, or over time form ice crystals, both that could impact the atmospheric radiative budget. The sensitivity simulations performed indicate that critical processes in the model causing a substantial change in the upper tropospheric Aitken mode number concentration are coagulation, condensation, nucleation scavenging, nucleation of aerosols and the transfer of aerosol mass and number between different aerosol bins. In particular, for aerosols in the Aitken mode to grow to CCN size, coagulation appears to be more important than condensation. Less important processes are dry deposition, impact scavenging and the initial vertical distribution and concentration of aerosols. It is interesting to note that in order to sustain a vigorous storm cloud, the supply of CCN must be continuous over a considerably long time period of the simulation. Hence, the treatment of the growth of particles is in general much more important than the initial aerosol concentration itself.

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Explicit simulations of aerosol physics in a cloud-resolving model: a sensitivity study based on an observed convective cloud

Atmospheric Chemistry and Physics ◽

10.5194/acp-4-773-2004 ◽

2004 ◽

Vol 4 (3) ◽

pp. 773-791 ◽

Cited By ~ 50

Author(s):

A. M. L. Ekman ◽

C. Wang ◽

J. Wilson ◽

J. Ström

Keyword(s):

Chemical Species ◽

Convective Cloud ◽

Sensitivity Study ◽

Substantial Part ◽

Cloud Droplets ◽

Upper Troposphere ◽

Cloud Resolving Model ◽

Long Time ◽

Nucleation Scavenging ◽

Aitken Mode

Abstract. The role of convection in introducing aerosols and promoting the formation of new particles to the upper troposphere has been examined using a cloud-resolving model coupled with an interactive explicit aerosol module. A baseline simulation suggests good agreement in the upper troposphere between modeled and observed results including concentrations of aerosols in different size ranges, mole fractions of key chemical species, and concentrations of ice particles. In addition, a set of 34 sensitivity simulations has been carried out to investigate the sensitivity of modeled results to the treatment of various aerosol physical and chemical processes in the model. The size distribution of aerosols is proved to be an important factor in determining the aerosols' fate within the convective cloud. Nucleation mode aerosols (here defined by 0≤d≤5.84 nm) are quickly transferred to the larger modes as they grow through coagulation of aerosols and condensation of H2SO4. Accumulation mode aerosols (here defined by d≥31.0 nm) are almost completely removed by nucleation (activation of cloud droplets) and impact scavenging. However, a substantial part (up to 10% of the boundary layer concentration) of the Aitken mode aerosol population (here defined by 5.84 nm≤d≤31.0 nm) reaches the top of the cloud and the free troposphere. These particles may continually survive in the upper troposphere, or over time form ice crystals, both that could impact on the atmospheric radiative budget. The sensitivity simulations performed indicate that critical processes in the model causing a substantial change in the upper tropospheric number concentration of Aitken mode aerosols are coagulation of aerosols, condensation of H2SO4, nucleation scavenging, nucleation of aerosols and the transfer of aerosol mass and number between different aerosol bins. In particular, for aerosols in the Aitken mode to grow to CCN size, coagulation of aerosols appears to be more important than condensation of H2SO4. Less important processes are dry deposition, impact scavenging and the initial vertical distribution and concentration of aerosols. It is interesting to note that in order to sustain a vigorous storm cloud, the supply of CCN must be continuous over a considerably long time period of the simulation. Hence, the treatment of the growth of particles is in general much more important than the initial aerosol concentration itself.

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Analysis on the Evolution and Microphysical Characteristics of Two Consecutive Hailstorms in Spring in Yunnan, China

Atmosphere ◽

10.3390/atmos12010063 ◽

2021 ◽

Vol 12 (1) ◽

pp. 63

Author(s):

Sidou Zhang ◽

Shiyin Liu ◽

Tengfei Zhang

Keyword(s):

Wind Speed ◽

Cloud Model ◽

Global Analysis ◽

Maximum Velocity ◽

Western Pacific Subtropical High ◽

Convective Cloud ◽

Radar Data ◽

Reanalysis Data ◽

Cloud Water ◽

High Level

By using products of the cloud model, National Centers for Environmental Prediction (NCEP) Final Operational Global Analysis (FNL) reanalysis data, and Doppler weather radar data, the mesoscale characteristics, microphysical structure, and mechanism of two hail cloud systems which occurred successively within 24 h in southeastern Yunnan have been analyzed. The results show that under the influence of two southwest jets in front of the south branch trough (SBT) and the periphery of the western Pacific subtropical high (WPSH), the northeast-southwest banded echoes affect the southeastern Yunnan of China twice. Meanwhile, the local mesoscale radial wind convergence and uneven wind speed lead to the intense development of convective echoes and the occurrence of hail. The simulated convective cloud bands are similar to the observation. The high-level mesoscale convergence line leads to the development of convective cloud bands. The low-level wind direction or wind speed convergence and the high-level wind speed divergence form a deep tilted updraft, with the maximum velocity of 15 m·s−1 at the −40~−10 °C layer, resulting in the intense development of local convective clouds. The hail embryos form through the conversion or collision growth of cloud water and snowflakes and have little to do with rain and ice crystals. Abundant cloud water, especially the accumulation region of high supercooled water (cloud water) near the 0 °C layer, is the key to the formation of hail embryos, in which qc is up to 1.92 g·kg−1 at the −4~−2 °C layer. The hail embryos mainly grow by collision-coalescence (collision-freezing) with cloud water (supercooled cloud drops) and snow crystal riming.

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Characterization of Transport Regimes and the Polar Dome during Arctic Spring and Summer using in-situ Aircraft Measurements

10.5194/acp-2019-70 ◽

2019 ◽

Cited By ~ 3

Author(s):

Heiko Bozem ◽

Peter Hoor ◽

Daniel Kunkel ◽

Franziska Köllner ◽

Johannes Schneider ◽

...

Keyword(s):

Lower Troposphere ◽

High Arctic ◽

The Arctic ◽

Trace Gas ◽

Second Phase ◽

Aerosol Formation ◽

Transport Barrier ◽

Data Set ◽

Air Masses ◽

Mixing Ratios

Abstract. The springtime composition of the Arctic lower troposphere is to a large extent controlled by transport of mid-latitude air masses into the Arctic, whereas during the summer precipitation and natural sources play the most important role. Within the Arctic region, there exists a transport barrier, known as the polar dome, which results from sloping isentropes. The polar dome, which varies in space and time, exhibits a strong influence on the transport of air masses from mid-latitudes, enhancing it during winter and inhibiting it during summer. Furthermore, a definition for the location of the polar dome boundary itself is quite sparse in the literature. We analyzed aircraft based trace gas measurements in the Arctic during two NETCARE airborne field camapigns (July 2014 and April 2015) with the Polar 6 aircraft of Alfred Wegener Institute Helmholtz Center for Polar and Marine Research (AWI), Bremerhaven, Germany, covering an area from Spitsbergen to Alaska (134° W to 17° W and 68° N to 83° N). For the spring (April 2015) and summer (July 2014) season we analyzed transport regimes of mid-latitude air masses travelling to the high Arctic based on CO and CO2 measurements as well as kinematic 10-day back trajectories. The dynamical isolation of the high Arctic lower troposphere caused by the transport barrier leads to gradients of chemical tracers reflecting different local chemical life times and sources and sinks. Particularly gradients of CO and CO2 allowed for a trace gas based definition of the polar dome boundary for the two measurement periods with pronounced seasonal differences. For both campaigns a transition zone rather than a sharp boundary was derived. For July 2014 the polar dome boundary was determined to be 73.5° N latitude and 299–303.5 K potential temperature, respectively. During April 2015 the polar dome boundary was on average located at 66–68.5° N and 283.5–287.5 K. Tracer-tracer scatter plots and probability density functions confirm different air mass properties inside and outside of the polar dome for the July 2014 and April 2015 data set. Using the tracer derived polar dome boundaries the analysis of aerosol data indicates secondary aerosol formation events in the clean summertime polar dome. Synoptic-scale weather systems frequently disturb this transport barrier and foster exchange between air masses from midlatitudes and polar regions. During the second phase of the NETCARE 2014 measurements a pronounced low pressure system south of Resolute Bay brought inflow from southern latitudes that pushed the polar dome northward and significantly affected trace gas mixing ratios in the measurement region. Mean CO mixing ratios increased from 77.9 ± 2.5 ppbv to 84.9 ± 4.7 ppbv from the first period to the second period. At the same time CO2 mixing ratios significantly dropped from 398.16 ± 1.01 ppmv to 393.81 ± 2.25 ppmv. We further analysed processes controlling the recent transport history of air masses within and outside the polar dome. Air masses within the spring time polar dome mainly experienced diabatic cooling while travelling over cold surfaces. In contrast air masses in the summertime polar dome were diabatically heated due to insolation. During both seasons air masses outside the polar dome slowly descended into the Arctic lower troposphere from above caused by radiative cooling. The ascent to the middle and upper troposphere mainly took place outside the Arctic, followed by a northward motion. Our results demonstrate the successful application of a tracer based diagnostic to determine the location of the polar dome boundary.

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The influence of typhoons on atmospheric composition deduced from IAGOS measurements over Taipei

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-3945-2020 ◽

2020 ◽

Vol 20 (6) ◽

pp. 3945-3963

Author(s):

Frank Roux ◽

Hannah Clark ◽

Kuo-Ying Wang ◽

Susanne Rohs ◽

Bastien Sauvage ◽

...

Keyword(s):

Carbon Monoxide ◽

Relative Humidity ◽

Tropical Cyclones ◽

Marine Boundary Layer ◽

Chemical Species ◽

Atmospheric Composition ◽

Commercial Aircraft ◽

Regular Feature ◽

Mixing Ratios ◽

The Vertical Distribution

Abstract. The research infrastructure IAGOS (In-Service Aircraft for a Global Observing System) equips commercial aircraft with instruments to monitor the composition of the atmosphere during flights around the world. In this article, we use data from two China Airlines aircraft based in Taipei (Taiwan) which provided daily measurements of ozone, carbon monoxide and water vapour throughout the summer of 2016. We present time series, from the surface to the upper troposphere, of ozone, carbon monoxide and relative humidity near Taipei, focusing on periods influenced by the passage of typhoons. We examine landing and take-off profiles in the vicinity of tropical cyclones using ERA-5 reanalyses to elucidate the origin of the anomalies in the vertical distribution of these chemical species. Results indicate a high ozone content in the upper- to middle-troposphere track of the storms. The high ozone mixing ratios are generally correlated with potential vorticity and anti-correlated with relative humidity, suggesting stratospheric origin. These results suggest that tropical cyclones participate in transporting air from the stratosphere to troposphere and that such transport could be a regular feature of typhoons. After the typhoons passed Taiwan, the tropospheric column was filled with substantially lower ozone mixing ratios due to the rapid uplift of marine boundary layer air. At the same time, the relative humidity increased, and carbon monoxide mixing ratios fell. Locally, therefore, the passage of typhoons has a positive effect on air quality at the surface, cleansing the atmosphere and reducing the mixing ratios of pollutants such as CO and O3.

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A laboratory and model investigation of secondary ice production during to supercooled drop collisions with ice surfaces

10.5194/egusphere-egu21-15696 ◽

2021 ◽

Author(s):

Paul Connolly ◽

Rachel James ◽

Vaughan Phillips

Keyword(s):

Laboratory Data ◽

Ice Formation ◽

Atmospheric Sciences ◽

Ice Particles ◽

Cold Room ◽

Mode 2 ◽

Rain Drops ◽

Break Up ◽

Ice Surfaces ◽

Ice Production

This work presents new laboratory data investigating collisions between supercooled drops and ice particles as a source of secondary ice particles in natural clouds. Furthermore we present numerical model simulations to put the laboratory measurements into context.Secondary ice particles form during the breakup of freezing drops due to so-called &#8220;spherical freezing&#8221; (or Mode 1),&#160;where an ice shell forms around the freezing drop. This process has been studied and observed for drops in free-fall&#160;in laboratory experiments since the 1960s, and also&#160;more recently by Lauber et al. (2018) with a high-speed camera. Aircraft field measurements (Lawson et al. 2015)&#160;and lab data (Kolomeychuk et al. 1975) suggest that such a process is dependent on the size of drops, with larger drops being more effective at producing secondary ice. &#160;Collision induced break-up of rain drops has been well studied with pioneering investigations in the mid-1980s, and numerous modelling studies showing that it is responsible for observed trimodal rain drop size distributions in the atmosphere, which can be well approximated by an exponential distribution.&#160;In mixed-phase clouds we know that rain-drops can collide with more massive&#160;ice particles. This, depending on the type of collision, may lead to the break-up of the supercooled drop (e.g. as hinted by Latham and Warwicker, 1980), potentially stimulating secondary ice formation (Phillips et al. 2018 - non-spherical, Mode 2).&#160; There is a dearth of laboratory data investigating this mechanism.&#160; This mechanism is the focus of the presentation.Here we present the results of recent experiments where we make use of the University of Manchester (UoM) cold room facility. The UoM cold room facility consists of 3 stacked cold rooms that can be cooled to temperatures below -55 degC. A new facility has been built to study secondary ice production via Mode 2 fragmentation. We generate supercooled drops at the top of the cold rooms and allow them to interact with different ice surfaces near the bottom. This interaction is filmed with a new&#160;camera setup.Our latest results will be presented at the conference.ReferencesKolomeychuk, R. J., D. C. McKay, and J. V. Iribarne. 1975. &#8220;The Fragmentation and Electrification of Freezing Drops.&#8221;&#160;Journal of the Atmospheric Sciences&#160;32 (5): 974&#8211;79. https://doi.org/10.1175/1520-0469(1975)032<0974>2.0.CO;2.Latham, J., and R. Warwicker. 1980. &#8220;Charge Transfer Accompanying the Splashing of Supercooled Raindrops on Hailstones.&#8221; Quarterly Journal of the Royal Meteorological Society 106 (449): 559&#8211;68. https://doi.org/10.1002/qj.49710644912.Lauber, Annika, Alexei Kiselev, Thomas Pander, Patricia Handmann, and Thomas Leisner. 2018. &#8220;Secondary Ice Formation during Freezing of Levitated Droplets.&#8221; Journal of the Atmospheric Sciences 75 (8): 2815&#8211;26. https://doi.org/10.1175/JAS-D-18-0052.1.Lawson, R. Paul, Sarah Woods, and Hugh Morrison. 2015. &#8220;The Microphysics of Ice and Precipitation Development in Tropical Cumulus Clouds.&#8221; Journal of the Atmospheric Sciences 72 (6): 2429&#8211;45. https://doi.org/10.1175/JAS-D-14-0274.1.&#160;&#160;

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Structural changes in the shallow and transition branch of the Brewer–Dobson circulation induced by El Niño

10.5194/acp-2018-688 ◽

2018 ◽

Author(s):

Mohamadou Diallo ◽

Paul Konopka ◽

Michelle L. Santee ◽

Rolf Müller ◽

Mengchu Tao ◽

...

Keyword(s):

El Niño ◽

Structural Changes ◽

Lower Stratosphere ◽

Transport Model ◽

El Nino ◽

Southern Oscillation ◽

Satellite Observations ◽

Trace Gas ◽

Residual Circulation ◽

Mixing Ratios

Abstract. The stratospheric Brewer–Dobson circulation (BD-circulation) determines the transport and lifetime of key radiatively active trace gases and further impacts surface climate through downward coupling. Here, we quantify the variability in the lower stratospheric BD-circulation induced by the El Nino Southern Oscillation (ENSO), using satellite trace gas measurements and simulations with the Lagrangian chemistry transport model, CLaMS, driven by ERA-Interim and JRA-55 reanalyses. We show that despite discrepancies in the deseasonalised ozone (O3) mixing ratios between CLaMS simulations and satellite observations, the patterns of changes in the lower stratospheric O3 anomalies induced by ENSO agree remarkably well over the 2005–2016 period. Particularly during the most recent El Niño in 2015–2016, both satellite observations and CLaMS simulations show the largest negative tropical O3 anomaly in the record. Regression analysis of different metrics of the BD-circulation strength, including mean age of air, vertical velocity, residual circulation and age spectrum, shows clear evidence for structural changes of the BD-circulation in the lower stratosphere induced by El Niño, consistent with observed O3 anomalies. These structural changes during El Niño include a weakening of the transition branch of the BD-circulation between about 370–420 K (∼ 100–70 hPa) and equatorward of about 60° and, a strengthening of the shallow branch at the same latitudes and between about 420–500 K (∼ 70–30 hPa). The strengthening of the shallow branch induces negative tropical O3 anomalies due to enhanced tropical upwelling, while the weakening of the transition branch combined with enhanced downwelling due to the strengthening shallow branch leads to positive O3 anomalies in the extratropical upper troposphere-lower stratosphere (UTLS). Our results suggest that a shift of the ENSO basic state toward more frequent El Niño-like conditions in a warming future climate will substantially alter UTLS trace gas distributions due to these changes in the vertical structure of the stratospheric circulation.

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Level 2 processing for the imaging Fourier transform spectrometer GLORIA: derivation and validation of temperature and trace gas volume mixing ratios from calibrated dynamics mode spectra

Atmospheric Measurement Techniques ◽

10.5194/amt-8-2473-2015 ◽

2015 ◽

Vol 8 (6) ◽

pp. 2473-2489 ◽

Cited By ~ 19

Author(s):

J. Ungermann ◽

J. Blank ◽

M. Dick ◽

A. Ebersoldt ◽

F. Friedl-Vallon ◽

...

Keyword(s):

Fourier Transform ◽

Horizontal Resolution ◽

Trace Gas ◽

Radiative Transfer Model ◽

Transfer Model ◽

Ionization Mass ◽

Fourier Transform Spectrometer ◽

Upper Troposphere ◽

Mixing Ratios

Abstract. The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) is an airborne infrared limb imager combining a two-dimensional infrared detector with a Fourier transform spectrometer. It was operated aboard the new German Gulfstream G550 High Altitude LOng Range (HALO) research aircraft during the Transport And Composition in the upper Troposphere/lowermost Stratosphere (TACTS) and Earth System Model Validation (ESMVAL) campaigns in summer 2012. This paper describes the retrieval of temperature and trace gas (H2O, O3, HNO3) volume mixing ratios from GLORIA dynamics mode spectra that are spectrally sampled every 0.625 cm−1. A total of 26 integrated spectral windows are employed in a joint fit to retrieve seven targets using consecutively a fast and an accurate tabulated radiative transfer model. Typical diagnostic quantities are provided including effects of uncertainties in the calibration and horizontal resolution along the line of sight. Simultaneous in situ observations by the Basic Halo Measurement and Sensor System (BAHAMAS), the Fast In-situ Stratospheric Hygrometer (FISH), an ozone detector named Fairo, and the Atmospheric chemical Ionization Mass Spectrometer (AIMS) allow a validation of retrieved values for three flights in the upper troposphere/lowermost stratosphere region spanning polar and sub-tropical latitudes. A high correlation is achieved between the remote sensing and the in situ trace gas data, and discrepancies can to a large extent be attributed to differences in the probed air masses caused by different sampling characteristics of the instruments. This 1-D processing of GLORIA dynamics mode spectra provides the basis for future tomographic inversions from circular and linear flight paths to better understand selected dynamical processes of the upper troposphere and lowermost stratosphere.

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