https://scholars.lib.ntu.edu.tw/handle/123456789/571663
標題: | Typhoon rainfall impact on drip water δ18O in Xianyun cave, Southeast China | 作者: | Yang Y Xu T Zhang X Ma L Lone M.A Jiang X. Mahjoor Ahmad Lone |
關鍵字: | Hurricanes; Isotopes; Rain; Rivers; Isotopic composition; Isotopic signatures; Monthly rainfalls; Negative deviations; Southeastern china; State of the art; Underground rivers; Variation characteristics; Reservoirs (water); cave; environmental monitoring; isotopic composition; karst; oxygen isotope; rainfall; river water; speleothem; stable isotope; typhoon; China | 公開日期: | 2021 | 卷: | 35 | 期: | 2 | 來源出版物: | Hydrological Processes | 摘要: | Precisely dated high-resolution speleothems may record past typhoon events, however, the state of the art cave monitoring is a prerequisite to identify suitable stalagmites for the reconstruction of such events. With this motivation, we examined the isotopic composition (δ18O and d-excess values) of rainfall, outside river, cave drip water, and an underground river in the Xianyun cave system, located in southeastern China. Monthly to bi-monthly monitoring of environmental and isotopic conditions was conducted for 1 year, from December 2018 to December 2019, including a typhoon event (August 24, 2019 to August 26, 2019), called Bailu. The δ18O of rainfall samples over the cave and outside river water ranged from ?9.7? to ?1.9? and ?8.2? to ?6.3?, respectively, while the δ18O of Typhoon Bailu rainfall and instantaneous outside river water ranged from ?19.6? to ?6.3? and ?10.4? to ?7.7?, respectively. Typhoon Bailu-induced rainfall showed distinctly negative δ18O values as compared to those of the monthly and bi-monthly rainfall, exhibiting a three-stage inverted U-shaped variation characteristic. Four drip water monitoring sites inside the cave revealed low variations during the studied period with average values of ?7.8?, ?8.0?, ?8.0?, and ?8.1?. However, during the typhoon, the drip water δ18O values exhibited similar characteristic as outside rainfall but with just 0.2? negative deviation owing to precipitation amount and drip water source reservoir. The integration of rainfall amount with drip water source reservoir determines the degree to which a typhoon isotopic signature gets diluted during epikarst infiltration. This study provides the first instrumental evidence of typhoon signal in karst system in southeastern China. Our results imply that the δ18O of drip water in Xianyun cave can instantaneously respond to typhoon rainfall. However, the 0.2? shift in drip water δ18O is difficult to be recorded by speleothems. We suggest multi-year monitoring to ascertain fully if the stalagmites could be used as paleotyphoon proxy. ? 2021 John Wiley & Sons Ltd |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-85101744315&doi=10.1002%2fhyp.14062&partnerID=40&md5=7d4bb316eca5c7b93f6e0dbfc2df02d8 https://scholars.lib.ntu.edu.tw/handle/123456789/571663 |
ISSN: | 8856087 | DOI: | 10.1002/hyp.14062 |
顯示於: | 地質科學系 |
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