Huawu Wu , Hongxiang Fan , Jing Li , Fu-Jun Yue , Ergang Lian , Congsheng Fu , Ruiyu Lei , Mengyao Ding , Jinzhao Liu , Xiao-Yan Li
{"title":"再现中国地表水δ18O和δ2H等值线:机器学习方法","authors":"Huawu Wu , Hongxiang Fan , Jing Li , Fu-Jun Yue , Ergang Lian , Congsheng Fu , Ruiyu Lei , Mengyao Ding , Jinzhao Liu , Xiao-Yan Li","doi":"10.1016/j.jhydrol.2024.131565","DOIUrl":null,"url":null,"abstract":"<div><p>The availability of comprehensive stable isotope data in China is limited, which hinders a thorough understanding of interpreting runoff sources and land–atmosphere water fluxes on a national scale. In this study, we have undertaken the task of establishing a dataset of surface water isotopes (δ<sup>18</sup>O and δ<sup>2</sup>H) to create surface water isoscapes, and identify its controlling factors. Our analysis, utilizing a random forest model (RF), indicates that the isotopic patterns observed in precipitation are well-reflected in river water across China. Specifically, the δ<sup>18</sup>O isoscape in river demonstrates enrichment in the Western arid zone and depletion in the Tibetan Plateau. These patterns are strongly influenced by hydro-climatic factors such as relative humidity, precipitation, and catchment properties, such as elevation. Notably, elevation is a significant variable in the RF model, governing the isotopic composition (δ<sup>18</sup>O and d-excess) of rivers throughout China, primarily due to the rainout effect resulting in isotopically-depleted precipitation from lowlands to elevated mountain regions. In contrast, surface water d-excess isoscape reveals a more complex spatial variability in China, mainly associated with contrasting moisture sources including maritime vapor from tropical oceans and inland recycling vapor. In addition, secondary evaporation processes resulted from cumulative dams and developed irrigation systems also contribute to this variability. Hence, catchment-scale evapotranspiration and instream evaporative processes contribute to the enrichment of downstream river water isotopes. The predictive surface water isoscapes will help understand the impact of changes in the hydrological cycle on a larger scale and provide practical guidance for future monitoring efforts and isotopic simulations.</p></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":null,"pages":null},"PeriodicalIF":5.9000,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Reproducing surface water isoscapes of δ18O and δ2H across China: A machine learning approach\",\"authors\":\"Huawu Wu , Hongxiang Fan , Jing Li , Fu-Jun Yue , Ergang Lian , Congsheng Fu , Ruiyu Lei , Mengyao Ding , Jinzhao Liu , Xiao-Yan Li\",\"doi\":\"10.1016/j.jhydrol.2024.131565\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The availability of comprehensive stable isotope data in China is limited, which hinders a thorough understanding of interpreting runoff sources and land–atmosphere water fluxes on a national scale. In this study, we have undertaken the task of establishing a dataset of surface water isotopes (δ<sup>18</sup>O and δ<sup>2</sup>H) to create surface water isoscapes, and identify its controlling factors. Our analysis, utilizing a random forest model (RF), indicates that the isotopic patterns observed in precipitation are well-reflected in river water across China. Specifically, the δ<sup>18</sup>O isoscape in river demonstrates enrichment in the Western arid zone and depletion in the Tibetan Plateau. These patterns are strongly influenced by hydro-climatic factors such as relative humidity, precipitation, and catchment properties, such as elevation. Notably, elevation is a significant variable in the RF model, governing the isotopic composition (δ<sup>18</sup>O and d-excess) of rivers throughout China, primarily due to the rainout effect resulting in isotopically-depleted precipitation from lowlands to elevated mountain regions. In contrast, surface water d-excess isoscape reveals a more complex spatial variability in China, mainly associated with contrasting moisture sources including maritime vapor from tropical oceans and inland recycling vapor. In addition, secondary evaporation processes resulted from cumulative dams and developed irrigation systems also contribute to this variability. Hence, catchment-scale evapotranspiration and instream evaporative processes contribute to the enrichment of downstream river water isotopes. The predictive surface water isoscapes will help understand the impact of changes in the hydrological cycle on a larger scale and provide practical guidance for future monitoring efforts and isotopic simulations.</p></div>\",\"PeriodicalId\":362,\"journal\":{\"name\":\"Journal of Hydrology\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":5.9000,\"publicationDate\":\"2024-07-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Hydrology\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0022169424009612\",\"RegionNum\":1,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"ENGINEERING, CIVIL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Hydrology","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0022169424009612","RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, CIVIL","Score":null,"Total":0}
Reproducing surface water isoscapes of δ18O and δ2H across China: A machine learning approach
The availability of comprehensive stable isotope data in China is limited, which hinders a thorough understanding of interpreting runoff sources and land–atmosphere water fluxes on a national scale. In this study, we have undertaken the task of establishing a dataset of surface water isotopes (δ18O and δ2H) to create surface water isoscapes, and identify its controlling factors. Our analysis, utilizing a random forest model (RF), indicates that the isotopic patterns observed in precipitation are well-reflected in river water across China. Specifically, the δ18O isoscape in river demonstrates enrichment in the Western arid zone and depletion in the Tibetan Plateau. These patterns are strongly influenced by hydro-climatic factors such as relative humidity, precipitation, and catchment properties, such as elevation. Notably, elevation is a significant variable in the RF model, governing the isotopic composition (δ18O and d-excess) of rivers throughout China, primarily due to the rainout effect resulting in isotopically-depleted precipitation from lowlands to elevated mountain regions. In contrast, surface water d-excess isoscape reveals a more complex spatial variability in China, mainly associated with contrasting moisture sources including maritime vapor from tropical oceans and inland recycling vapor. In addition, secondary evaporation processes resulted from cumulative dams and developed irrigation systems also contribute to this variability. Hence, catchment-scale evapotranspiration and instream evaporative processes contribute to the enrichment of downstream river water isotopes. The predictive surface water isoscapes will help understand the impact of changes in the hydrological cycle on a larger scale and provide practical guidance for future monitoring efforts and isotopic simulations.
期刊介绍:
The Journal of Hydrology publishes original research papers and comprehensive reviews in all the subfields of the hydrological sciences including water based management and policy issues that impact on economics and society. These comprise, but are not limited to the physical, chemical, biogeochemical, stochastic and systems aspects of surface and groundwater hydrology, hydrometeorology and hydrogeology. Relevant topics incorporating the insights and methodologies of disciplines such as climatology, water resource systems, hydraulics, agrohydrology, geomorphology, soil science, instrumentation and remote sensing, civil and environmental engineering are included. Social science perspectives on hydrological problems such as resource and ecological economics, environmental sociology, psychology and behavioural science, management and policy analysis are also invited. Multi-and interdisciplinary analyses of hydrological problems are within scope. The science published in the Journal of Hydrology is relevant to catchment scales rather than exclusively to a local scale or site.