GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    Evaluation of modelled climatologies of O 3 , CO, water vapour and NO y in the upper troposphere–lower stratosphere using regular in situ observations by passenger aircraft
    Copernicus GmbH ; 2023
    In:  Atmospheric Chemistry and Physics Vol. 23, No. 23 ( 2023-12-06), p. 14973-15009
    Details
    In: Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 23, No. 23 ( 2023-12-06), p. 14973-15009
    Abstract: Abstract. Evaluating global chemistry models in the upper troposphere–lower stratosphere (UTLS) is an important step toward an improved understanding of the chemical composition in this region. This composition is regularly sampled through in situ measurements based on passenger aircraft, in the framework of the In-service Aircraft for a Global Observing System (IAGOS) research infrastructure. This study focuses on the comparison of the IAGOS measurements in ozone, carbon monoxide (CO), nitrogen reactive species (NOy) and water vapour, with a 25-year simulation output from the LMDZ-OR-INCA chemistry–climate model. For this purpose, we present and apply an extension of the Interpol-IAGOS software that projects the IAGOS data onto any model grid, in order to derive a gridded IAGOS product and a masked (sub-sampled) model product that are directly comparable to one another. Climatologies are calculated in the upper troposphere (UT) and in the lower stratosphere (LS) separately but also in the UTLS as a whole, as a demonstration for the models that do not sort out the physical variables necessary to distinguish between the UT and the LS. In the northern extratropics, the comparison in the UTLS layer suggests that the geographical distribution in the tropopause height is well reproduced by the model. In the separated layers, the model simulates well the water vapour climatologies in the UT and the ozone climatologies in the LS. There are opposite biases in CO in both UT and LS, which suggests that the cross-tropopause transport is overestimated. The NOy observations highlight the difficulty of the model in parameterizing the lightning emissions. In the tropics, the upper-tropospheric climatologies are remarkably well simulated for water vapour. They also show realistic CO peaks due to biomass burning in the most convective systems, and the ozone latitudinal variations are well correlated between the observations and the model. Ozone is more sensitive to lightning emissions than to biomass burning emissions, whereas the CO sensitivity to biomass burning emissions strongly depends on location and season. The present study demonstrates that the Interpol-IAGOS software is a tool facilitating the assessment of global model simulations in the UTLS, which is potentially useful for any modelling experiment involving chemistry climate or chemistry transport models.
    Type of Medium: Online Resource
    ISSN: 1680-7324
    URL: Article
    URL: Article
    DOI: 10.5194/acp-23-14973-2023
    DOI: 10.5194/acp-23-14973-2023-supplement
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2023
    detail.hit.zdb_id: 2069847-1
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    In situ observations of aerosol properties above ice saturation in the polar tropopause region
    American Geophysical Union (AGU) ; 2000
    In:  Journal of Geophysical Research: Atmospheres Vol. 105, No. D24 ( 2000-12-27), p. 29387-29395
    Details
    In: Journal of Geophysical Research: Atmospheres, American Geophysical Union (AGU), Vol. 105, No. D24 ( 2000-12-27), p. 29387-29395
    Abstract: In the polar winter tropopause region (T≅ 200 K, p = 200 hPa) over northern Europe, the occurrence of a haze‐mode aerosol in the diameter range 0.75 μm 〈 D 〈 10 μm was frequently observed during airborne in situ measurements of aerosol properties. In ascending air parcels the haze mode was detected as soon as a water saturation ratio S wν = 0.5 ( S ice ≅ 1.0) was exceeded. Larger cirrus particles with size D 〉 10 μm where found in regions with S wν 〉 0.57 ( S ice ≥ 1.17). Hence, a range of S wν values existed between 0.5 and 0.57, where the haze mode was present outside of cirrus clouds. The ratio of number densities of haze‐mode particles to Aitken‐mode particles reached ∼1.25% inside and 〈 0.3% outside of ice‐supersaturated regions. In descending air parcels a continuous decrease in the number density of haze‐mode particles was observed. This suggests a deliquescence transition in rising air parcels and evaporation of liquid haze droplets without recrystallization in sinking air parcels. Consideration of the possible chemical composition, phase, and growth timescales of the haze‐mode particles leads to the conclusion that they are likely to contain ammoniated sulfates in the liquid phase. On the basis of measured particle sizes and calculated extinction values, the observed haze mode may be a candidate for subvisible cirrus cloud particles.
    Type of Medium: Online Resource
    ISSN: 0148-0227
    URL: Article
    DOI: 10.1029/2000JD900474
    Language: English
    Publisher: American Geophysical Union (AGU)
    Publication Date: 2000
    detail.hit.zdb_id: 2033040-6
    detail.hit.zdb_id: 3094104-0
    detail.hit.zdb_id: 2130824-X
    detail.hit.zdb_id: 2016813-5
    detail.hit.zdb_id: 2016810-X
    detail.hit.zdb_id: 2403298-0
    detail.hit.zdb_id: 2016800-7
    detail.hit.zdb_id: 161666-3
    detail.hit.zdb_id: 161667-5
    detail.hit.zdb_id: 2969341-X
    detail.hit.zdb_id: 161665-1
    detail.hit.zdb_id: 3094268-8
    detail.hit.zdb_id: 710256-2
    detail.hit.zdb_id: 2016804-4
    detail.hit.zdb_id: 3094181-7
    detail.hit.zdb_id: 3094219-6
    detail.hit.zdb_id: 3094167-2
    detail.hit.zdb_id: 2220777-6
    detail.hit.zdb_id: 3094197-0
    SSG: 16,13
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    Mercury Plumes in the Global Upper Troposphere Observed during Flights with the CARIBIC Observatory from May 2005 until June 2013
    MDPI AG ; 2014
    In:  Atmosphere Vol. 5, No. 2 ( 2014-05-28), p. 342-369
    Details
    In: Atmosphere, MDPI AG, Vol. 5, No. 2 ( 2014-05-28), p. 342-369
    Type of Medium: Online Resource
    ISSN: 2073-4433
    URL: Article
    DOI: 10.3390/atmos5020342
    Language: English
    Publisher: MDPI AG
    Publication Date: 2014
    detail.hit.zdb_id: 2605928-9
    SSG: 23
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    Impact of the South Asian monsoon outflow on atmospheric hydroperoxides in the upper troposphere
    Copernicus GmbH ; 2020
    In:  Atmospheric Chemistry and Physics Vol. 20, No. 21 ( 2020-11-03), p. 12655-12673
    Details
    In: Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 20, No. 21 ( 2020-11-03), p. 12655-12673
    Abstract: Abstract. During the OMO (Oxidation Mechanism Observation) mission, trace gas measurements were performed on board the HALO (High Altitude Long Range) research aircraft in summer 2015 in order to investigate the outflow of the South Asian summer monsoon and its influence on the composition of the Asian monsoon anticyclone (AMA) in the upper troposphere over the eastern Mediterranean and the Arabian Peninsula. This study focuses on in situ observations of hydrogen peroxide (H2O2obs) and organic hydroperoxides (ROOHobs) as well as their precursors and loss processes. Observations are compared to photostationary-state (PSS) calculations of H2O2PSS and extended by a separation of ROOHobs into methyl hydroperoxide (MHPPSS) and inferred unidentified hydroperoxide (UHPPSS) mixing ratios using PSS calculations. Measurements are also contrasted to simulations with the general circulation ECHAM–MESSy for Atmospheric Chemistry (EMAC) model. We observed enhanced mixing ratios of H2O2obs (45 %), MHPPSS (9 %), and UHPPSS (136 %) in the AMA relative to the northern hemispheric background. Highest concentrations for H2O2obs and MHPPSS of 211 and 152 ppbv, respectively, were found in the tropics outside the AMA, while for UHPPSS, with 208 pptv, highest concentrations were found within the AMA. In general, the observed concentrations are higher than steady-state calculations and EMAC simulations by a factor of 3 and 2, respectively. Especially in the AMA, EMAC underestimates the H2O2EMAC (medians: 71 pptv vs. 164 pptv) and ROOHEMAC (medians: 25 pptv vs. 278 pptv) mixing ratios. Longitudinal gradients indicate a pool of hydroperoxides towards the center of the AMA, most likely associated with upwind convection over India. This indicates main contributions of atmospheric transport to the local budgets of hydroperoxides along the flight track, explaining strong deviations from steady-state calculations which only account for local photochemistry. Underestimation of H2O2EMAC by approximately a factor of 2 in the Northern Hemisphere (NH) and the AMA and overestimation in the Southern Hemisphere (SH; factor 1.3) are most likely due to uncertainties in the scavenging efficiencies for individual hydroperoxides in deep convective transport to the upper troposphere, corroborated by a sensitivity study. It seems that the observed excess UHPPSS is excess MHP transported to the west from an upper tropospheric source related to convection in the summer monsoon over Southeast Asia.
    Type of Medium: Online Resource
    ISSN: 1680-7324
    URL: Article
    DOI: 10.5194/acp-20-12655-2020
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2020
    detail.hit.zdb_id: 2092549-9
    detail.hit.zdb_id: 2069847-1
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 5
    Online Resource
    Online Resource
    Dynamics and composition of the Asian summer monsoon anticyclone
    Copernicus GmbH ; 2018
    In:  Atmospheric Chemistry and Physics Vol. 18, No. 8 ( 2018-04-24), p. 5655-5675
    Details
    In: Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 18, No. 8 ( 2018-04-24), p. 5655-5675
    Abstract: Abstract. This study places HALO research aircraft observations in the upper-tropospheric Asian summer monsoon anticyclone (ASMA) into the context of regional, intra-annual variability by hindcasts with the ECHAM/MESSy Atmospheric Chemistry (EMAC) model. The observations were obtained during the Earth System Model Validation (ESMVal) campaign in September 2012. Observed and simulated tracer–tracer relations reflect photochemical O3 production as well as in-mixing from the lower troposphere and the tropopause layer. The simulations demonstrate that tropospheric trace gas profiles in the monsoon season are distinct from those in the rest of the year, and the measurements reflect the main processes acting throughout the monsoon season. Net photochemical O3 production is significantly enhanced in the ASMA, where uplifted precursors meet increased NOx, mainly produced by lightning. 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. Radial transport barriers of the circulation are effectively overcome by subseasonal dynamical instabilities of the anticyclone, which occur quite frequently and are of paramount importance for the trace gas composition of the ASMA. Both the isentropic entrainment of O3-rich air and the photochemical conversion of uplifted O3-poor air tend to increase O3 in the ASMA outflow.
    Type of Medium: Online Resource
    ISSN: 1680-7324
    URL: Article
    URL: Article
    DOI: 10.5194/acp-18-5655-2018
    DOI: 10.5194/acp-18-5655-2018-supplement
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2018
    detail.hit.zdb_id: 2092549-9
    detail.hit.zdb_id: 2069847-1
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 6
    Online Resource
    Online Resource
    Overview: On the transport and transformation of pollutants in the outflow of major population centres – observational data from the EMeRGe European intensive operational period in summer 2017
    Copernicus GmbH ; 2022
    In:  Atmospheric Chemistry and Physics Vol. 22, No. 9 ( 2022-05-05), p. 5877-5924
    Details
    In: Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 22, No. 9 ( 2022-05-05), p. 5877-5924
    Abstract: Abstract. Megacities and other major population centres (MPCs) worldwide are major sources of air pollution, both locally as well as downwind. The overall assessment and prediction of the impact of MPC pollution on tropospheric chemistry are challenging. The present work provides an overview of the highlights of a major new contribution to the understanding of this issue based on the data and analysis of the EMeRGe (Effect of Megacities on the transport and transformation of pollutants on the Regional to Global scales) international project. EMeRGe focuses on atmospheric chemistry, dynamics, and transport of local and regional pollution originating in MPCs. Airborne measurements, taking advantage of the long range capabilities of the High Altitude and LOng Range Research Aircraft (HALO, https://www.halo-spp.de, last access: 22 March 2022), are a central part of the project. The synergistic use and consistent interpretation of observational data sets of different spatial and temporal resolution (e.g. from ground-based networks, airborne campaigns, and satellite measurements) supported by modelling within EMeRGe provide unique insight to test the current understanding of MPC pollution outflows. In order to obtain an adequate set of measurements at different spatial scales, two field experiments were positioned in time and space to contrast situations when the photochemical transformation of plumes emerging from MPCs is large. These experiments were conducted in summer 2017 over Europe and in the inter-monsoon period over Asia in spring 2018. The intensive observational periods (IOPs) involved HALO airborne measurements of ozone and its precursors, volatile organic compounds, aerosol particles, and related species as well as coordinated ground-based ancillary observations at different sites. Perfluorocarbon (PFC) tracer releases and model forecasts supported the flight planning, the identification of pollution plumes, and the analysis of chemical transformations during transport. This paper describes the experimental deployment and scientific questions of the IOP in Europe. The MPC targets – London (United Kingdom; UK), the Benelux/Ruhr area (Belgium, the Netherlands, Luxembourg and Germany), Paris (France), Rome and the Po Valley (Italy), and Madrid and Barcelona (Spain) – were investigated during seven HALO research flights with an aircraft base in Germany for a total of 53 flight hours. An in-flight comparison of HALO with the collaborating UK-airborne platform Facility for Airborne Atmospheric Measurements (FAAM) took place to assure accuracy and comparability of the instrumentation on board. Overall, EMeRGe unites measurements of near- and far-field emissions and hence deals with complex air masses of local and distant sources. Regional transport of several European MPC outflows was successfully identified and measured. Chemical processing of the MPC emissions was inferred from airborne observations of primary and secondary pollutants and the ratios between species having different chemical lifetimes. Photochemical processing of aerosol and secondary formation or organic acids was evident during the transport of MPC plumes. Urban plumes mix efficiently with natural sources as mineral dust and with biomass burning emissions from vegetation and forest fires. This confirms the importance of wildland fire emissions in Europe and indicates an important but discontinuous contribution to the European emission budget that might be of relevance in the design of efficient mitigation strategies. The present work provides an overview of the most salient results in the European context, with these being addressed in more detail within additional dedicated EMeRGe studies. The deployment and results obtained in Asia will be the subject of separate publications.
    Type of Medium: Online Resource
    ISSN: 1680-7324
    URL: Article
    URL: Article
    DOI: 10.5194/acp-22-5877-2022
    DOI: 10.5194/acp-22-5877-2022-supplement
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2022
    detail.hit.zdb_id: 2092549-9
    detail.hit.zdb_id: 2069847-1
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 7
    Online Resource
    Online Resource
    Redistribution of total reactive nitrogen in the lowermost Arctic stratosphere during the cold winter 2015/2016
    Copernicus GmbH ; 2022
    In:  Atmospheric Chemistry and Physics Vol. 22, No. 5 ( 2022-03-17), p. 3631-3654
    Details
    In: Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 22, No. 5 ( 2022-03-17), p. 3631-3654
    Abstract: Abstract. During winter 2015/2016, the Arctic stratosphere was characterized by extraordinarily low temperatures in connection with a very strong polar vortex and with the occurrence of extensive polar stratospheric clouds. From mid-December 2015 until mid-March 2016, the German research aircraft HALO (High Altitude and Long-Range Research Aircraft) was deployed to probe the lowermost stratosphere in the Arctic region within the POLSTRACC (Polar Stratosphere in a Changing Climate) mission. More than 20 flights have been conducted out of Kiruna, Sweden, and Oberpfaffenhofen, Germany, covering the whole winter period. Besides total reactive nitrogen (NOy), observations of nitrous oxide, nitric acid, ozone, and water were used for this study. Total reactive nitrogen and its partitioning between the gas and particle phases are key parameters for understanding processes controlling the ozone budget in the polar winter stratosphere. The vertical redistribution of total reactive nitrogen was evaluated by using tracer–tracer correlations (NOy–N2O and NOy–O3). The trace gases are well correlated as long as the NOy distribution is controlled by its gas-phase production from N2O. Deviations of the observed NOy from this correlation indicate the influence of heterogeneous processes. In early winter no such deviations have been observed. In January, however, air masses with extensive nitrification were encountered at altitudes between 12 and 15 km. The excess NOy amounted to about 6 ppb. During several flights, along with gas-phase nitrification, indications for extensive occurrence of nitric acid containing particles at flight altitude were found. These observations support the assumption of sedimentation and subsequent evaporation of nitric acid-containing particles, leading to redistribution of total reactive nitrogen at lower altitudes. Remnants of nitrified air masses have been observed until mid-March. Between the end of February and mid-March, denitrified air masses have also been observed in connection with high potential temperatures. This indicates the downward transport of air masses that have been denitrified during the earlier winter phase. Using tracer–tracer correlations, missing total reactive nitrogen was estimated to amount to 6 ppb. Further, indications of transport and mixing of these processed air masses outside the vortex have been found, contributing to the chemical budget of the winter lowermost stratosphere. Observations within POLSTRACC, at the bottom of the vortex, reflect heterogeneous processes from the overlying Arctic winter stratosphere. The comparison of the observations with CLaMS model simulations confirm and complete the picture arising from the present measurements. The simulations confirm that the ensemble of all observations is representative of the vortex-wide vertical NOy redistribution.
    Type of Medium: Online Resource
    ISSN: 1680-7324
    URL: Article
    DOI: 10.5194/acp-22-3631-2022
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2022
    detail.hit.zdb_id: 2092549-9
    detail.hit.zdb_id: 2069847-1
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 8
    Online Resource
    Online Resource
    Measurements of nitrogen oxides from aircraft in the northeast Atlantic flight corridor
    American Geophysical Union (AGU) ; 1998
    In:  Journal of Geophysical Research: Atmospheres Vol. 103, No. D23 ( 1998-12-20), p. 31217-31229
    Details
    In: Journal of Geophysical Research: Atmospheres, American Geophysical Union (AGU), Vol. 103, No. D23 ( 1998-12-20), p. 31217-31229
    Abstract: We investigated the size and composition of exhaust plumes of commercial airliners in the northeast Atlantic flight corridor off the shores of Ireland and Scotland, an area with high air traffic density in the tropopause region. The primary objective was to measure the contribution of the NO and NO y emitted from aircraft to the nitrogen oxide background. We have made measurements in aircraft flight corridors by flying a research aircraft perpendicular to the routes of commercial transatlantic air traffic. Although previous studies had succeeded in identifying a few plumes, this study was the first systematic investigation of over 60 aircraft plumes through in situ NO and NO y measurements. These plumes were up to 1.5 km wide (along our flight paths) and showed NO y mixing ratios of up to 10 ppb above the background levels. The measurements showed that on larger scales the composition of NO y in the background air masses was very heterogeneous. On top of this natural variability of the NO y , we could not identify any influence of air traffic exhaust on air chemistry on scales larger than a few kilometers from our data. A secondary objective was to estimate the importance of the oxidation of NO χ to NO y in the relatively fresh plumes. The measured NO/NO y ratios were near the NO/NO χ ratios calculated from a simple photo‐stationary state assumption. This result was also consistent with calculations made with an expanding box model that included gas‐phase chemistry for the measured plume conditions. The model calculated NO/NO y and NC/NO χ ratios were almost equal, and these were consistent with the measured NO/NO y , ratios. These calculations showed that oxidation of NO χ to higher oxides played only a negligible role in our measured plumes of ages between 14 and 90 min.
    Type of Medium: Online Resource
    ISSN: 0148-0227
    URL: Article
    DOI: 10.1029/98JD02624
    Language: English
    Publisher: American Geophysical Union (AGU)
    Publication Date: 1998
    detail.hit.zdb_id: 2033040-6
    detail.hit.zdb_id: 3094104-0
    detail.hit.zdb_id: 2130824-X
    detail.hit.zdb_id: 2016813-5
    detail.hit.zdb_id: 2016810-X
    detail.hit.zdb_id: 2403298-0
    detail.hit.zdb_id: 2016800-7
    detail.hit.zdb_id: 161666-3
    detail.hit.zdb_id: 161667-5
    detail.hit.zdb_id: 2969341-X
    detail.hit.zdb_id: 161665-1
    detail.hit.zdb_id: 3094268-8
    detail.hit.zdb_id: 710256-2
    detail.hit.zdb_id: 2016804-4
    detail.hit.zdb_id: 3094181-7
    detail.hit.zdb_id: 3094219-6
    detail.hit.zdb_id: 3094167-2
    detail.hit.zdb_id: 2220777-6
    detail.hit.zdb_id: 3094197-0
    SSG: 16,13
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 9
    Online Resource
    Online Resource
    Global-scale atmosphere monitoring by in-service aircraft – current achievements and future prospects of the European Research Infrastructure IAGOS
    Stockholm University Press ; 2015
    In:  Tellus B: Chemical and Physical Meteorology Vol. 67, No. 1 ( 2015-01-01), p. 28452-
    Details
    In: Tellus B: Chemical and Physical Meteorology, Stockholm University Press, Vol. 67, No. 1 ( 2015-01-01), p. 28452-
    Type of Medium: Online Resource
    ISSN: 1600-0889 , 0280-6509
    URL: Article
    DOI: 10.3402/tellusb.v67.28452
    RVK:
    RA 1000
    RVK:
    UA 8382.2
    Language: Unknown
    Publisher: Stockholm University Press
    Publication Date: 2015
    detail.hit.zdb_id: 2026992-4
    detail.hit.zdb_id: 246061-0
    SSG: 16,13
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 10
    Online Resource
    Online Resource
    3-D tomographic observations of Rossby wave breaking over the North Atlantic during the WISE aircraft campaign in 2017
    Copernicus GmbH ; 2021
    In:  Atmospheric Chemistry and Physics Vol. 21, No. 13 ( 2021-07-07), p. 10249-10272
    Details
    In: Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 21, No. 13 ( 2021-07-07), p. 10249-10272
    Abstract: Abstract. This paper presents measurements of ozone, water vapour and nitric acid (HNO3) in the upper troposphere/lower stratosphere (UTLS) over North Atlantic and Europe. The measurements were acquired with the Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) during the Wave Driven Isentropic Exchange (WISE) campaign in October 2017. GLORIA is an airborne limb imager capable of acquiring both 2-D data sets (curtains along the flight path) and, when the carrier aircraft is flying around the observed air mass, spatially highly resolved 3-D tomographic data. Here, we present a case study of a Rossby wave (RW) breaking event observed during two subsequent flights 2 d apart. RW breaking is known to steepen tracer gradients and facilitate stratosphere–troposphere exchange (STE). Our measurements reveal complex spatial structures in stratospheric tracers (ozone and nitric acid) with multiple vertically stacked filaments. Backward-trajectory analysis is used to demonstrate that these features are related to several previous Rossby wave breaking events and that the small-scale structure of the UTLS in the Rossby wave breaking region, which is otherwise very hard to observe, can be understood as stirring and mixing of air masses of tropospheric and stratospheric origin. It is also shown that a strong nitric acid enhancement observed just above the tropopause is likely a result of NOx production by lightning activity. The measurements showed signatures of enhanced mixing between stratospheric and tropospheric air near the polar jet with some transport of water vapour into the stratosphere. Some of the air masses seen in 3-D data were encountered again 2 d later, stretched to very thin filament (horizontal thickness down to 30 km at some altitudes) rich in stratospheric tracers. This repeated measurement allowed us to directly observe and analyse the progress of mixing processes in a thin filament over 2 d. Our results provide direct insight into small-scale dynamics of the UTLS in the Rossby wave breaking region, which is of great importance to understanding STE and poleward transport in the UTLS.
    Type of Medium: Online Resource
    ISSN: 1680-7324
    URL: Article
    DOI: 10.5194/acp-21-10249-2021
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2021
    detail.hit.zdb_id: 2092549-9
    detail.hit.zdb_id: 2069847-1
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...