A Case Study on Drivers of the Isotopic Composition of Water Vapour at the Coast of East Antarctica
Stable water isotopes (SWIs) contain valuable information on the past climate and phase changes in the hydrologic cycle. Recently, vapour measurements in the polar regions have provided new insights into the effects of snow-related and atmospheric processes on SWIs. The purpose of this study is to e...
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Online Access: | https://doi.org/10.22541/essoar.167340708.83192511/v1 https://essopenarchive.org/users/574481/articles/618237-a-case-study-on-drivers-of-the-isotopic-composition-of-water-vapour-at-the-coast-of-east-antarctica?commit=33f58fc74c90e9e16eadfc5b45b659a2acfbf7f2 https://infoscience.epfl.ch/record/299210/files/953609_0_merged_1673016251.pdf http://infoscience.epfl.ch/record/299210 |
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ftinfoscience:oai:infoscience.epfl.ch:299210 2023-05-15T13:43:17+02:00 A Case Study on Drivers of the Isotopic Composition of Water Vapour at the Coast of East Antarctica Chaar, Riqo Sigmund, Armin Ebner, Pirmin Philipp Lehning, Michael 2023-01-13T17:21:23Z https://doi.org/10.22541/essoar.167340708.83192511/v1 https://essopenarchive.org/users/574481/articles/618237-a-case-study-on-drivers-of-the-isotopic-composition-of-water-vapour-at-the-coast-of-east-antarctica?commit=33f58fc74c90e9e16eadfc5b45b659a2acfbf7f2 https://infoscience.epfl.ch/record/299210/files/953609_0_merged_1673016251.pdf http://infoscience.epfl.ch/record/299210 unknown doi:10.22541/essoar.167340708.83192511/v1 https://essopenarchive.org/users/574481/articles/618237-a-case-study-on-drivers-of-the-isotopic-composition-of-water-vapour-at-the-coast-of-east-antarctica?commit=33f58fc74c90e9e16eadfc5b45b659a2acfbf7f2 https://infoscience.epfl.ch/record/299210/files/953609_0_merged_1673016251.pdf http://infoscience.epfl.ch/record/299210 http://infoscience.epfl.ch/record/299210 Text 2023 ftinfoscience https://doi.org/10.22541/essoar.167340708.83192511/v1 2023-02-13T23:13:07Z Stable water isotopes (SWIs) contain valuable information on the past climate and phase changes in the hydrologic cycle. Recently, vapour measurements in the polar regions have provided new insights into the effects of snow-related and atmospheric processes on SWIs. The purpose of this study is to elucidate the drivers of the particularly depleted vapour isotopic composition measured on a ship close to the East Antarctic coast during the Antarctic Circumnavigation Expedition in 2017. Reanalysis data and backward trajectories are used to model the isotopic composition of air parcels arriving in the atmospheric boundary layer (ABL) above the ship. A novel approach is developed to account for moisture exchanges with the snow surface. The model generally reproduces the observed trend with strongly depleted vapour δ18O values in the middle of the 6-day study period. This depletion is caused by direct air mass advection from the ice sheet where the vapour is more depleted in heavy SWIs due to distillation during cloud formation. The time spent by the air masses in the marine ABL shortly before arrival at the ship is crucial as ocean evaporation typically leads to an abrupt change in the isotopic signature. Snow sublimation is another important driver because the air masses and the sublimation flux will differ substantially in their isotopic composition if the air masses cross the ocean-snow boundary or descend from higher atmospheric levels. Although our model makes strong simplifications, it is a useful and computationally efficient method for understanding SWI dynamics at polar sites. Text Antarc* Antarctic Antarctica East Antarctica Ice Sheet EPFL Infoscience (Ecole Polytechnique Fédérale Lausanne) Antarctic East Antarctica The Antarctic |
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Open Polar |
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EPFL Infoscience (Ecole Polytechnique Fédérale Lausanne) |
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ftinfoscience |
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unknown |
description |
Stable water isotopes (SWIs) contain valuable information on the past climate and phase changes in the hydrologic cycle. Recently, vapour measurements in the polar regions have provided new insights into the effects of snow-related and atmospheric processes on SWIs. The purpose of this study is to elucidate the drivers of the particularly depleted vapour isotopic composition measured on a ship close to the East Antarctic coast during the Antarctic Circumnavigation Expedition in 2017. Reanalysis data and backward trajectories are used to model the isotopic composition of air parcels arriving in the atmospheric boundary layer (ABL) above the ship. A novel approach is developed to account for moisture exchanges with the snow surface. The model generally reproduces the observed trend with strongly depleted vapour δ18O values in the middle of the 6-day study period. This depletion is caused by direct air mass advection from the ice sheet where the vapour is more depleted in heavy SWIs due to distillation during cloud formation. The time spent by the air masses in the marine ABL shortly before arrival at the ship is crucial as ocean evaporation typically leads to an abrupt change in the isotopic signature. Snow sublimation is another important driver because the air masses and the sublimation flux will differ substantially in their isotopic composition if the air masses cross the ocean-snow boundary or descend from higher atmospheric levels. Although our model makes strong simplifications, it is a useful and computationally efficient method for understanding SWI dynamics at polar sites. |
format |
Text |
author |
Chaar, Riqo Sigmund, Armin Ebner, Pirmin Philipp Lehning, Michael |
spellingShingle |
Chaar, Riqo Sigmund, Armin Ebner, Pirmin Philipp Lehning, Michael A Case Study on Drivers of the Isotopic Composition of Water Vapour at the Coast of East Antarctica |
author_facet |
Chaar, Riqo Sigmund, Armin Ebner, Pirmin Philipp Lehning, Michael |
author_sort |
Chaar, Riqo |
title |
A Case Study on Drivers of the Isotopic Composition of Water Vapour at the Coast of East Antarctica |
title_short |
A Case Study on Drivers of the Isotopic Composition of Water Vapour at the Coast of East Antarctica |
title_full |
A Case Study on Drivers of the Isotopic Composition of Water Vapour at the Coast of East Antarctica |
title_fullStr |
A Case Study on Drivers of the Isotopic Composition of Water Vapour at the Coast of East Antarctica |
title_full_unstemmed |
A Case Study on Drivers of the Isotopic Composition of Water Vapour at the Coast of East Antarctica |
title_sort |
case study on drivers of the isotopic composition of water vapour at the coast of east antarctica |
publishDate |
2023 |
url |
https://doi.org/10.22541/essoar.167340708.83192511/v1 https://essopenarchive.org/users/574481/articles/618237-a-case-study-on-drivers-of-the-isotopic-composition-of-water-vapour-at-the-coast-of-east-antarctica?commit=33f58fc74c90e9e16eadfc5b45b659a2acfbf7f2 https://infoscience.epfl.ch/record/299210/files/953609_0_merged_1673016251.pdf http://infoscience.epfl.ch/record/299210 |
geographic |
Antarctic East Antarctica The Antarctic |
geographic_facet |
Antarctic East Antarctica The Antarctic |
genre |
Antarc* Antarctic Antarctica East Antarctica Ice Sheet |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica Ice Sheet |
op_source |
http://infoscience.epfl.ch/record/299210 |
op_relation |
doi:10.22541/essoar.167340708.83192511/v1 https://essopenarchive.org/users/574481/articles/618237-a-case-study-on-drivers-of-the-isotopic-composition-of-water-vapour-at-the-coast-of-east-antarctica?commit=33f58fc74c90e9e16eadfc5b45b659a2acfbf7f2 https://infoscience.epfl.ch/record/299210/files/953609_0_merged_1673016251.pdf http://infoscience.epfl.ch/record/299210 |
op_doi |
https://doi.org/10.22541/essoar.167340708.83192511/v1 |
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