Investigation and amelioration of long-term instrumental drifts in water vapor and nitrous oxide measurements from the Aura Microwave Limb Sounder (MLS) and their implications for studies of variability and trends
The Microwave Limb Sounder (MLS), launched on NASA's Aura spacecraft in 2004, measures vertical profiles of the abundances of key atmospheric species from the upper troposphere to the mesosphere with daily near-global coverage. We review the first 15 years of the record of H 2 O and N 2 O measu...
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ftdoajarticles:oai:doaj.org/article:0659c0038a874978a1ae775577cef1eb 2023-05-15T13:51:44+02:00 Investigation and amelioration of long-term instrumental drifts in water vapor and nitrous oxide measurements from the Aura Microwave Limb Sounder (MLS) and their implications for studies of variability and trends N. J. Livesey W. G. Read L. Froidevaux A. Lambert M. L. Santee M. J. Schwartz L. F. Millán R. F. Jarnot P. A. Wagner D. F. Hurst K. A. Walker P. E. Sheese G. E. Nedoluha 2021-10-01T00:00:00Z https://doi.org/10.5194/acp-21-15409-2021 https://doaj.org/article/0659c0038a874978a1ae775577cef1eb EN eng Copernicus Publications https://acp.copernicus.org/articles/21/15409/2021/acp-21-15409-2021.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-21-15409-2021 1680-7316 1680-7324 https://doaj.org/article/0659c0038a874978a1ae775577cef1eb Atmospheric Chemistry and Physics, Vol 21, Pp 15409-15430 (2021) Physics QC1-999 Chemistry QD1-999 article 2021 ftdoajarticles https://doi.org/10.5194/acp-21-15409-2021 2022-12-31T07:59:39Z The Microwave Limb Sounder (MLS), launched on NASA's Aura spacecraft in 2004, measures vertical profiles of the abundances of key atmospheric species from the upper troposphere to the mesosphere with daily near-global coverage. We review the first 15 years of the record of H 2 O and N 2 O measurements from the MLS 190 GHz subsystem (along with other 190 GHz information), with a focus on their long-term stability, largely based on comparisons with measurements from other sensors. These comparisons generally show signs of an increasing drift in the MLS “version 4” (v4) H 2 O record starting around 2010. Specifically, comparisons with v4.1 measurements from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) indicate a ∼ 2 %–3 % per decade drift over much of the stratosphere, increasing to as much as ∼ 7 % per decade around 46 hPa. Larger drifts, of around 7 %–11 % per decade, are seen in comparisons to balloon-borne frost point hygrometer measurements in the lower stratosphere. Microphysical calculations considering the formation of polar stratospheric clouds in the Antarctic winter stratosphere corroborate a drift in MLS v4 water vapor measurements in that region and season. In contrast, comparisons with the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on NASA's Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) mission, and with ground-based Water Vapor Millimeter-wave Spectrometer (WVMS) instruments, do not show statistically significant drifts. However, the uncertainty in these comparisons is large enough to encompass most of the drifts identified in other comparisons. In parallel, the MLS v4 N 2 O product is shown to be generally decreasing over the same period (when an increase in stratospheric N 2 O is expected, reflecting a secular growth in emissions), with a more pronounced drift in the lower stratosphere than that found for H 2 O . Comparisons to ACE-FTS and to MLS N 2 O observations in a different spectral region, with the ... Article in Journal/Newspaper Antarc* Antarctic Directory of Open Access Journals: DOAJ Articles Antarctic The Antarctic Atmospheric Chemistry and Physics 21 20 15409 15430 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Physics QC1-999 Chemistry QD1-999 |
spellingShingle |
Physics QC1-999 Chemistry QD1-999 N. J. Livesey W. G. Read L. Froidevaux A. Lambert M. L. Santee M. J. Schwartz L. F. Millán R. F. Jarnot P. A. Wagner D. F. Hurst K. A. Walker P. E. Sheese G. E. Nedoluha Investigation and amelioration of long-term instrumental drifts in water vapor and nitrous oxide measurements from the Aura Microwave Limb Sounder (MLS) and their implications for studies of variability and trends |
topic_facet |
Physics QC1-999 Chemistry QD1-999 |
description |
The Microwave Limb Sounder (MLS), launched on NASA's Aura spacecraft in 2004, measures vertical profiles of the abundances of key atmospheric species from the upper troposphere to the mesosphere with daily near-global coverage. We review the first 15 years of the record of H 2 O and N 2 O measurements from the MLS 190 GHz subsystem (along with other 190 GHz information), with a focus on their long-term stability, largely based on comparisons with measurements from other sensors. These comparisons generally show signs of an increasing drift in the MLS “version 4” (v4) H 2 O record starting around 2010. Specifically, comparisons with v4.1 measurements from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) indicate a ∼ 2 %–3 % per decade drift over much of the stratosphere, increasing to as much as ∼ 7 % per decade around 46 hPa. Larger drifts, of around 7 %–11 % per decade, are seen in comparisons to balloon-borne frost point hygrometer measurements in the lower stratosphere. Microphysical calculations considering the formation of polar stratospheric clouds in the Antarctic winter stratosphere corroborate a drift in MLS v4 water vapor measurements in that region and season. In contrast, comparisons with the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on NASA's Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) mission, and with ground-based Water Vapor Millimeter-wave Spectrometer (WVMS) instruments, do not show statistically significant drifts. However, the uncertainty in these comparisons is large enough to encompass most of the drifts identified in other comparisons. In parallel, the MLS v4 N 2 O product is shown to be generally decreasing over the same period (when an increase in stratospheric N 2 O is expected, reflecting a secular growth in emissions), with a more pronounced drift in the lower stratosphere than that found for H 2 O . Comparisons to ACE-FTS and to MLS N 2 O observations in a different spectral region, with the ... |
format |
Article in Journal/Newspaper |
author |
N. J. Livesey W. G. Read L. Froidevaux A. Lambert M. L. Santee M. J. Schwartz L. F. Millán R. F. Jarnot P. A. Wagner D. F. Hurst K. A. Walker P. E. Sheese G. E. Nedoluha |
author_facet |
N. J. Livesey W. G. Read L. Froidevaux A. Lambert M. L. Santee M. J. Schwartz L. F. Millán R. F. Jarnot P. A. Wagner D. F. Hurst K. A. Walker P. E. Sheese G. E. Nedoluha |
author_sort |
N. J. Livesey |
title |
Investigation and amelioration of long-term instrumental drifts in water vapor and nitrous oxide measurements from the Aura Microwave Limb Sounder (MLS) and their implications for studies of variability and trends |
title_short |
Investigation and amelioration of long-term instrumental drifts in water vapor and nitrous oxide measurements from the Aura Microwave Limb Sounder (MLS) and their implications for studies of variability and trends |
title_full |
Investigation and amelioration of long-term instrumental drifts in water vapor and nitrous oxide measurements from the Aura Microwave Limb Sounder (MLS) and their implications for studies of variability and trends |
title_fullStr |
Investigation and amelioration of long-term instrumental drifts in water vapor and nitrous oxide measurements from the Aura Microwave Limb Sounder (MLS) and their implications for studies of variability and trends |
title_full_unstemmed |
Investigation and amelioration of long-term instrumental drifts in water vapor and nitrous oxide measurements from the Aura Microwave Limb Sounder (MLS) and their implications for studies of variability and trends |
title_sort |
investigation and amelioration of long-term instrumental drifts in water vapor and nitrous oxide measurements from the aura microwave limb sounder (mls) and their implications for studies of variability and trends |
publisher |
Copernicus Publications |
publishDate |
2021 |
url |
https://doi.org/10.5194/acp-21-15409-2021 https://doaj.org/article/0659c0038a874978a1ae775577cef1eb |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Atmospheric Chemistry and Physics, Vol 21, Pp 15409-15430 (2021) |
op_relation |
https://acp.copernicus.org/articles/21/15409/2021/acp-21-15409-2021.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-21-15409-2021 1680-7316 1680-7324 https://doaj.org/article/0659c0038a874978a1ae775577cef1eb |
op_doi |
https://doi.org/10.5194/acp-21-15409-2021 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
21 |
container_issue |
20 |
container_start_page |
15409 |
op_container_end_page |
15430 |
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