Observation of a slanted moisture structure with weak updraft leading to localized heavy rainfalls

Abstract Understanding moisture structures within moist low-level jets (MLLJs) that fuel moisture into mesoscale convective systems (MCSs) is essential for revealing the development of MCSs that cause localized heavy rainfalls. The moisture structure in MLLJs and the mechanisms that determine it are...

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Main Authors: Satoru Yoshida, Tetsu Sakai, Tomohiro Nagai, Hiromu Seko, Teruyuki Kato, Koichi Shiraishi, Shingo Shimizu
Format: Article
Language:English
Published: Nature Portfolio 2025-07-01
Series:Scientific Reports
Online Access:https://doi.org/10.1038/s41598-025-02314-2
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author Satoru Yoshida
Tetsu Sakai
Tomohiro Nagai
Hiromu Seko
Teruyuki Kato
Koichi Shiraishi
Shingo Shimizu
author_facet Satoru Yoshida
Tetsu Sakai
Tomohiro Nagai
Hiromu Seko
Teruyuki Kato
Koichi Shiraishi
Shingo Shimizu
author_sort Satoru Yoshida
collection DOAJ
description Abstract Understanding moisture structures within moist low-level jets (MLLJs) that fuel moisture into mesoscale convective systems (MCSs) is essential for revealing the development of MCSs that cause localized heavy rainfalls. The moisture structure in MLLJs and the mechanisms that determine it are unclear. We used radiosondes, a water vapor lidar, and Doppler lidar to observe MLLJs in Kyushu, western Japan. The observations revealed an unstable moist layer that was saturated or nearly saturated and that extended vertically from near the surface to more than 1 km above sea level in the MLLJ. The thickness of the moist layer gradually increased with a slant angle of less than 1° toward the MCS. The MLLJ involved weak updrafts below the cloud bases that contributed to thickening the slanted moist layer via vertical transport of moisture. The slanted moisture structure with a weak updraft appeared to effectively fuel moisture into MCSs and led to localized heavy rainfalls.
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institution Kabale University
issn 2045-2322
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publishDate 2025-07-01
publisher Nature Portfolio
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series Scientific Reports
spelling doaj-art-0941f148de4a4a0eb3ad30d0fcd237052025-08-20T03:45:20ZengNature PortfolioScientific Reports2045-23222025-07-011511910.1038/s41598-025-02314-2Observation of a slanted moisture structure with weak updraft leading to localized heavy rainfallsSatoru Yoshida0Tetsu Sakai1Tomohiro Nagai2Hiromu Seko3Teruyuki Kato4Koichi Shiraishi5Shingo Shimizu6Meteorological Research InstituteMeteorological Research InstituteMeteorological Research InstituteMeteorological Research InstituteMeteorological Research InstituteFukuoka UniversityNational Research Institute for Earth Science and Disaster ResilienceAbstract Understanding moisture structures within moist low-level jets (MLLJs) that fuel moisture into mesoscale convective systems (MCSs) is essential for revealing the development of MCSs that cause localized heavy rainfalls. The moisture structure in MLLJs and the mechanisms that determine it are unclear. We used radiosondes, a water vapor lidar, and Doppler lidar to observe MLLJs in Kyushu, western Japan. The observations revealed an unstable moist layer that was saturated or nearly saturated and that extended vertically from near the surface to more than 1 km above sea level in the MLLJ. The thickness of the moist layer gradually increased with a slant angle of less than 1° toward the MCS. The MLLJ involved weak updrafts below the cloud bases that contributed to thickening the slanted moist layer via vertical transport of moisture. The slanted moisture structure with a weak updraft appeared to effectively fuel moisture into MCSs and led to localized heavy rainfalls.https://doi.org/10.1038/s41598-025-02314-2
spellingShingle Satoru Yoshida
Tetsu Sakai
Tomohiro Nagai
Hiromu Seko
Teruyuki Kato
Koichi Shiraishi
Shingo Shimizu
Observation of a slanted moisture structure with weak updraft leading to localized heavy rainfalls
Scientific Reports
title Observation of a slanted moisture structure with weak updraft leading to localized heavy rainfalls
title_full Observation of a slanted moisture structure with weak updraft leading to localized heavy rainfalls
title_fullStr Observation of a slanted moisture structure with weak updraft leading to localized heavy rainfalls
title_full_unstemmed Observation of a slanted moisture structure with weak updraft leading to localized heavy rainfalls
title_short Observation of a slanted moisture structure with weak updraft leading to localized heavy rainfalls
title_sort observation of a slanted moisture structure with weak updraft leading to localized heavy rainfalls
url https://doi.org/10.1038/s41598-025-02314-2
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