Disentangling different moisture transport pathways over the eastern subtropical North Atlantic using multi-platform isotope observations and high-resolution numerical modelling
Due to its dryness, the subtropical free troposphere plays a critical role in the radiative balance of the Earth's climate system. But the complex interactions of the dynamical and physical processes controlling the variability in the moisture budget of this sensitive region of the subtropical...
Published in: | Atmospheric Chemistry and Physics |
---|---|
Main Authors: | , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Copernicus Publications
2021
|
Subjects: | |
Online Access: | https://doi.org/10.5194/acp-21-16319-2021 https://doaj.org/article/20c76147d9644ddfaf7ef671937076d9 |
id |
ftdoajarticles:oai:doaj.org/article:20c76147d9644ddfaf7ef671937076d9 |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:20c76147d9644ddfaf7ef671937076d9 2023-05-15T17:32:08+02:00 Disentangling different moisture transport pathways over the eastern subtropical North Atlantic using multi-platform isotope observations and high-resolution numerical modelling F. Dahinden F. Aemisegger H. Wernli M. Schneider C. J. Diekmann B. Ertl P. Knippertz M. Werner S. Pfahl 2021-11-01T00:00:00Z https://doi.org/10.5194/acp-21-16319-2021 https://doaj.org/article/20c76147d9644ddfaf7ef671937076d9 EN eng Copernicus Publications https://acp.copernicus.org/articles/21/16319/2021/acp-21-16319-2021.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-21-16319-2021 1680-7316 1680-7324 https://doaj.org/article/20c76147d9644ddfaf7ef671937076d9 Atmospheric Chemistry and Physics, Vol 21, Pp 16319-16347 (2021) Physics QC1-999 Chemistry QD1-999 article 2021 ftdoajarticles https://doi.org/10.5194/acp-21-16319-2021 2022-12-31T07:12:18Z Due to its dryness, the subtropical free troposphere plays a critical role in the radiative balance of the Earth's climate system. But the complex interactions of the dynamical and physical processes controlling the variability in the moisture budget of this sensitive region of the subtropical atmosphere are still not fully understood. Stable water isotopes can provide important information about several of the latter processes, namely subsidence drying, turbulent mixing, and dry and moist convective moistening. In this study, we use high-resolution simulations of the isotope-enabled version of the regional weather and climate prediction model of the Consortium for Small-Scale Modelling (COSMO iso ) to investigate predominant moisture transport pathways in the Canary Islands region in the eastern subtropical North Atlantic. Comparison of the simulated isotope signals with multi-platform isotope observations (aircraft, ground- and space-based remote sensing) from a field campaign in summer 2013 shows that COSMO iso can reproduce the observed variability of stable water vapour isotopes on timescales of hours to days, thus allowing us to study the mechanisms that control the subtropical free-tropospheric humidity. Changes in isotopic signals along backward trajectories from the Canary Islands region reveal the physical processes behind the synoptic-scale isotope variability. We identify four predominant moisture transport pathways of mid-tropospheric air, each with distinct isotopic signatures: air parcels originating from the convective boundary layer of the Saharan heat low (SHL) – these are characterised by a homogeneous isotopic composition with a particularly high δ D (median mid-tropospheric <math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" overflow="scroll" dspmath="mathml"><mrow><mi mathvariant="italic">δ</mi><mrow class="chem"><mi mathvariant="normal">D</mi></mrow><mo>=</mo><mo>-</mo><mn ... Article in Journal/Newspaper North Atlantic Directory of Open Access Journals: DOAJ Articles Atmospheric Chemistry and Physics 21 21 16319 16347 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Physics QC1-999 Chemistry QD1-999 |
spellingShingle |
Physics QC1-999 Chemistry QD1-999 F. Dahinden F. Aemisegger H. Wernli M. Schneider C. J. Diekmann B. Ertl P. Knippertz M. Werner S. Pfahl Disentangling different moisture transport pathways over the eastern subtropical North Atlantic using multi-platform isotope observations and high-resolution numerical modelling |
topic_facet |
Physics QC1-999 Chemistry QD1-999 |
description |
Due to its dryness, the subtropical free troposphere plays a critical role in the radiative balance of the Earth's climate system. But the complex interactions of the dynamical and physical processes controlling the variability in the moisture budget of this sensitive region of the subtropical atmosphere are still not fully understood. Stable water isotopes can provide important information about several of the latter processes, namely subsidence drying, turbulent mixing, and dry and moist convective moistening. In this study, we use high-resolution simulations of the isotope-enabled version of the regional weather and climate prediction model of the Consortium for Small-Scale Modelling (COSMO iso ) to investigate predominant moisture transport pathways in the Canary Islands region in the eastern subtropical North Atlantic. Comparison of the simulated isotope signals with multi-platform isotope observations (aircraft, ground- and space-based remote sensing) from a field campaign in summer 2013 shows that COSMO iso can reproduce the observed variability of stable water vapour isotopes on timescales of hours to days, thus allowing us to study the mechanisms that control the subtropical free-tropospheric humidity. Changes in isotopic signals along backward trajectories from the Canary Islands region reveal the physical processes behind the synoptic-scale isotope variability. We identify four predominant moisture transport pathways of mid-tropospheric air, each with distinct isotopic signatures: air parcels originating from the convective boundary layer of the Saharan heat low (SHL) – these are characterised by a homogeneous isotopic composition with a particularly high δ D (median mid-tropospheric <math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" overflow="scroll" dspmath="mathml"><mrow><mi mathvariant="italic">δ</mi><mrow class="chem"><mi mathvariant="normal">D</mi></mrow><mo>=</mo><mo>-</mo><mn ... |
format |
Article in Journal/Newspaper |
author |
F. Dahinden F. Aemisegger H. Wernli M. Schneider C. J. Diekmann B. Ertl P. Knippertz M. Werner S. Pfahl |
author_facet |
F. Dahinden F. Aemisegger H. Wernli M. Schneider C. J. Diekmann B. Ertl P. Knippertz M. Werner S. Pfahl |
author_sort |
F. Dahinden |
title |
Disentangling different moisture transport pathways over the eastern subtropical North Atlantic using multi-platform isotope observations and high-resolution numerical modelling |
title_short |
Disentangling different moisture transport pathways over the eastern subtropical North Atlantic using multi-platform isotope observations and high-resolution numerical modelling |
title_full |
Disentangling different moisture transport pathways over the eastern subtropical North Atlantic using multi-platform isotope observations and high-resolution numerical modelling |
title_fullStr |
Disentangling different moisture transport pathways over the eastern subtropical North Atlantic using multi-platform isotope observations and high-resolution numerical modelling |
title_full_unstemmed |
Disentangling different moisture transport pathways over the eastern subtropical North Atlantic using multi-platform isotope observations and high-resolution numerical modelling |
title_sort |
disentangling different moisture transport pathways over the eastern subtropical north atlantic using multi-platform isotope observations and high-resolution numerical modelling |
publisher |
Copernicus Publications |
publishDate |
2021 |
url |
https://doi.org/10.5194/acp-21-16319-2021 https://doaj.org/article/20c76147d9644ddfaf7ef671937076d9 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Atmospheric Chemistry and Physics, Vol 21, Pp 16319-16347 (2021) |
op_relation |
https://acp.copernicus.org/articles/21/16319/2021/acp-21-16319-2021.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-21-16319-2021 1680-7316 1680-7324 https://doaj.org/article/20c76147d9644ddfaf7ef671937076d9 |
op_doi |
https://doi.org/10.5194/acp-21-16319-2021 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
21 |
container_issue |
21 |
container_start_page |
16319 |
op_container_end_page |
16347 |
_version_ |
1766130089269919744 |