Uncovering below cloud rain‐vapor interactions during tropical rain events through simultaneous and continuous real‐time monitoring of rain and vapor isotopes
Due to limited water vapor measurements, vapor isotopes have been traditionally estimated under the assumption of isotopic equilibrium between rain and vapor below cloud base. However, recent advancements in analytical instruments allow more vapor isotopic measurements that have challenged this assu...
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sg-ntu-dr.10356-1820992025-01-13T15:30:49Z Uncovering below cloud rain‐vapor interactions during tropical rain events through simultaneous and continuous real‐time monitoring of rain and vapor isotopes He, Shaoneng Jackisch, Dominik Feng, Lujia Samanta, Dhrubajyoti Wang, Xianfeng Goodkin, Nathalie F. Asian School of the Environment Earth Observatory of Singapore Earth and Environmental Sciences Below-cloud processes Rain evaporation Due to limited water vapor measurements, vapor isotopes have been traditionally estimated under the assumption of isotopic equilibrium between rain and vapor below cloud base. However, recent advancements in analytical instruments allow more vapor isotopic measurements that have challenged this assumption. To enhance our understanding of rain-vapor interactions below cloud base in tropical regions, we established an automated system to measure rain and vapor isotopes simultaneously and continuously in real time at minute intervals in Singapore. Among 324 rain events monitored from 2016 to 2019, 81% exhibited a substantial departure of rain and vapor isotopes from the expected equilibrium. This departure suggests that raindrop evaporation plays a larger role in determining their isotopes. The conclusion is supported by the generally lower slopes of the local meteoric water line. Seasonal variations in rain event characteristics indicate changing influences of rain-vapor interactions: during monsoons, more frequent heavy rainfall maintains relatively high humidity below cloud base, favoring rain-vapor isotopic equilibrium, whereas during inter-monsoons, more light rain events lead to pronounced rain evaporation and larger isotopic differences. Furthermore, rain-vapor interactions below cloud base significantly modulated their isotope evolution during individual events. As events progressed, reduced humidity favored evaporation, increasing rain isotope values and decreasing its d-excess, whereas vapor isotope values decreased and its d-excess increased. Our study introduces a new approach to capturing real-time high-resolution rain and vapor isotopes at minute intervals to understand the dynamics of rain-vapor interactions below cloud base. Findings underscore the crucial role of these interactions in influencing rain and vapor isotopes during tropical rain events. Ministry of Education (MOE) National Research Foundation (NRF) Published version The authors gratefully acknowledge the financial support provided by the Singapore Ministry of Education (Grant MOE‐MOET2EP10121‐0008). This research is also supported by the National Research Foundation Singapore and the Singapore Ministry of Education under the Research Centers of Excellence initiative. 2025-01-07T08:01:12Z 2025-01-07T08:01:12Z 2024 Journal Article He, S., Jackisch, D., Feng, L., Samanta, D., Wang, X. & Goodkin, N. F. (2024). Uncovering below cloud rain‐vapor interactions during tropical rain events through simultaneous and continuous real‐time monitoring of rain and vapor isotopes. Journal of Geophysical Research: Atmospheres, 129(22). https://dx.doi.org/10.1029/2023JD040084 2169-897X https://hdl.handle.net/10356/182099 10.1029/2023JD040084 2-s2.0-85208957939 22 129 en MOE‐MOET2EP10121‐0008 Journal of Geophysical Research: Atmospheres © 2024 American Geophysical Union. All rights reserved. This article may be downloaded for personal use only. Any other use requires prior permission of the copyright holder. The Version of Record is available online at http://doi.org/10.1029/2023JD040084 application/pdf |
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Earth and Environmental Sciences Below-cloud processes Rain evaporation He, Shaoneng Jackisch, Dominik Feng, Lujia Samanta, Dhrubajyoti Wang, Xianfeng Goodkin, Nathalie F. Uncovering below cloud rain‐vapor interactions during tropical rain events through simultaneous and continuous real‐time monitoring of rain and vapor isotopes |
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Due to limited water vapor measurements, vapor isotopes have been traditionally estimated under the assumption of isotopic equilibrium between rain and vapor below cloud base. However, recent advancements in analytical instruments allow more vapor isotopic measurements that have challenged this assumption. To enhance our understanding of rain-vapor interactions below cloud base in tropical regions, we established an automated system to measure rain and vapor isotopes simultaneously and continuously in real time at minute intervals in Singapore. Among 324 rain events monitored from 2016 to 2019, 81% exhibited a substantial departure of rain and vapor isotopes from the expected equilibrium. This departure suggests that raindrop evaporation plays a larger role in determining their isotopes. The conclusion is supported by the generally lower slopes of the local meteoric water line. Seasonal variations in rain event characteristics indicate changing influences of rain-vapor interactions: during monsoons, more frequent heavy rainfall maintains relatively high humidity below cloud base, favoring rain-vapor isotopic equilibrium, whereas during inter-monsoons, more light rain events lead to pronounced rain evaporation and larger isotopic differences. Furthermore, rain-vapor interactions below cloud base significantly modulated their isotope evolution during individual events. As events progressed, reduced humidity favored evaporation, increasing rain isotope values and decreasing its d-excess, whereas vapor isotope values decreased and its d-excess increased. Our study introduces a new approach to capturing real-time high-resolution rain and vapor isotopes at minute intervals to understand the dynamics of rain-vapor interactions below cloud base. Findings underscore the crucial role of these interactions in influencing rain and vapor isotopes during tropical rain events. |
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Asian School of the Environment |
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Asian School of the Environment He, Shaoneng Jackisch, Dominik Feng, Lujia Samanta, Dhrubajyoti Wang, Xianfeng Goodkin, Nathalie F. |
format |
Article |
author |
He, Shaoneng Jackisch, Dominik Feng, Lujia Samanta, Dhrubajyoti Wang, Xianfeng Goodkin, Nathalie F. |
author_sort |
He, Shaoneng |
title |
Uncovering below cloud rain‐vapor interactions during tropical rain events through simultaneous and continuous real‐time monitoring of rain and vapor isotopes |
title_short |
Uncovering below cloud rain‐vapor interactions during tropical rain events through simultaneous and continuous real‐time monitoring of rain and vapor isotopes |
title_full |
Uncovering below cloud rain‐vapor interactions during tropical rain events through simultaneous and continuous real‐time monitoring of rain and vapor isotopes |
title_fullStr |
Uncovering below cloud rain‐vapor interactions during tropical rain events through simultaneous and continuous real‐time monitoring of rain and vapor isotopes |
title_full_unstemmed |
Uncovering below cloud rain‐vapor interactions during tropical rain events through simultaneous and continuous real‐time monitoring of rain and vapor isotopes |
title_sort |
uncovering below cloud rain‐vapor interactions during tropical rain events through simultaneous and continuous real‐time monitoring of rain and vapor isotopes |
publishDate |
2025 |
url |
https://hdl.handle.net/10356/182099 |
_version_ |
1821279338695229440 |