The strong activity of noctilucent clouds at middle latitudes in 2020
The 2020 summer season had more frequent than usual occurrences of noctilucent clouds (NLCs) in the Northern Hemisphere at middle latitudes (45–50°N), with the lowest latitude at which NLCs were seen being 34.1°N. In order to investigate a reason for this extraordinary NLC season, we have analyzed l...
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ftnipr:oai:nipr.repo.nii.ac.jp:00017339 2023-06-11T04:16:12+02:00 The strong activity of noctilucent clouds at middle latitudes in 2020 2023-03 https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=17339 http://id.nii.ac.jp/1291/00017203/ en eng https://doi.org/10.1016/j.polar.2022.100920 https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=17339 http://id.nii.ac.jp/1291/00017203/ Polar Science, 100920(2023-03) 18739652 Noctilucent clouds Summer mesopause Solar activity Journal Article 2023 ftnipr https://doi.org/10.1016/j.polar.2022.100920 2023-04-29T19:34:29Z The 2020 summer season had more frequent than usual occurrences of noctilucent clouds (NLCs) in the Northern Hemisphere at middle latitudes (45–50°N), with the lowest latitude at which NLCs were seen being 34.1°N. In order to investigate a reason for this extraordinary NLC season, we have analyzed long-term Aura/MLS satellite data for all available summer periods from 2005 to 2021. Both Aura/MLS summer temperature and water vapor in the mesopause region, between about 79 and 89 km altitude, have been considered. There has been a decrease in the summer mesopause temperature between 2016 and 2020. At the same time, water vapor mixing ratio has significantly increased (by about 12–17%) in the zonal mean H2O value in the 2020 summer compared to 2017. There exists a positive linear trend in the H2O amount by about 5% between 2005 and 2021 at middle latitudes 45–50°N at 0.0046 hPa. A combination of lower mesopause temperature and water vapor mixing ratio maximum at middle latitudes is the main reason for frequent and widespread occurrences of NLCs seen around the globe at middle latitudes in the summer of 2020. The 24th solar cycle minimum can explain neither the H2O maximum nor NLC maximum in 2020. Article in Journal/Newspaper Polar Science Polar Science National Institute of Polar Research Repository, Japan Polar Science 35 100920 |
institution |
Open Polar |
collection |
National Institute of Polar Research Repository, Japan |
op_collection_id |
ftnipr |
language |
English |
topic |
Noctilucent clouds Summer mesopause Solar activity |
spellingShingle |
Noctilucent clouds Summer mesopause Solar activity The strong activity of noctilucent clouds at middle latitudes in 2020 |
topic_facet |
Noctilucent clouds Summer mesopause Solar activity |
description |
The 2020 summer season had more frequent than usual occurrences of noctilucent clouds (NLCs) in the Northern Hemisphere at middle latitudes (45–50°N), with the lowest latitude at which NLCs were seen being 34.1°N. In order to investigate a reason for this extraordinary NLC season, we have analyzed long-term Aura/MLS satellite data for all available summer periods from 2005 to 2021. Both Aura/MLS summer temperature and water vapor in the mesopause region, between about 79 and 89 km altitude, have been considered. There has been a decrease in the summer mesopause temperature between 2016 and 2020. At the same time, water vapor mixing ratio has significantly increased (by about 12–17%) in the zonal mean H2O value in the 2020 summer compared to 2017. There exists a positive linear trend in the H2O amount by about 5% between 2005 and 2021 at middle latitudes 45–50°N at 0.0046 hPa. A combination of lower mesopause temperature and water vapor mixing ratio maximum at middle latitudes is the main reason for frequent and widespread occurrences of NLCs seen around the globe at middle latitudes in the summer of 2020. The 24th solar cycle minimum can explain neither the H2O maximum nor NLC maximum in 2020. |
format |
Article in Journal/Newspaper |
title |
The strong activity of noctilucent clouds at middle latitudes in 2020 |
title_short |
The strong activity of noctilucent clouds at middle latitudes in 2020 |
title_full |
The strong activity of noctilucent clouds at middle latitudes in 2020 |
title_fullStr |
The strong activity of noctilucent clouds at middle latitudes in 2020 |
title_full_unstemmed |
The strong activity of noctilucent clouds at middle latitudes in 2020 |
title_sort |
strong activity of noctilucent clouds at middle latitudes in 2020 |
publishDate |
2023 |
url |
https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=17339 http://id.nii.ac.jp/1291/00017203/ |
genre |
Polar Science Polar Science |
genre_facet |
Polar Science Polar Science |
op_relation |
https://doi.org/10.1016/j.polar.2022.100920 https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=17339 http://id.nii.ac.jp/1291/00017203/ Polar Science, 100920(2023-03) 18739652 |
op_doi |
https://doi.org/10.1016/j.polar.2022.100920 |
container_title |
Polar Science |
container_volume |
35 |
container_start_page |
100920 |
_version_ |
1768373704609234944 |