Comparison of Intra-Event Characteristics of Hydrogen and Oxygen Stable Isotopes between Rainfall and Throughfall and the Effects of Pre-Event Precipitation
The isotopic composition of precipitation provides valuable information about its source and transportation. However, raindrops interact with vegetation before reaching the earth’s surface, leading to isotopic changes in the infiltrating water. Comparing isotopic composition between rainfall and thr...
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| Format: | Article |
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MDPI AG
2023-08-01
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| Series: | Forests |
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| Online Access: | https://www.mdpi.com/1999-4907/14/8/1603 |
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| author | Chengcheng Xia Guodong Liu Yuchuan Meng Ke Chen |
| author_facet | Chengcheng Xia Guodong Liu Yuchuan Meng Ke Chen |
| author_sort | Chengcheng Xia |
| collection | DOAJ |
| description | The isotopic composition of precipitation provides valuable information about its source and transportation. However, raindrops interact with vegetation before reaching the earth’s surface, leading to isotopic changes in the infiltrating water. Comparing isotopic composition between rainfall and throughfall helps to understand canopy processes and their impact on isotopic variation. Based on observational data collected during the periods of July 2019, July–August 2020, and July–August 2021 in a planted forest located in the southwest monsoon region of China, this study examines hydrogen and oxygen isotopes in rainfall and throughfall at event and intra-event scales, and investigates the effects of pre-event precipitation (PEP) on the isotopic composition. The results indicate that during the initial stage of precipitation, δ<sup>18</sup>O was enriched in rainfall and it presented a dilution effect gradually, while the d-excess exhibits a low initial value followed by an increasing trend. The difference in δ<sup>18</sup>O between throughfall and rainfall initially increased and subsequently converged around 0, whereas the difference in d-excess experiences a decreasing phase, followed by an increasing phase, and finally a decreasing phase. Canopy interception led to a lag effect during the early stage of precipitation; the forest exhibited higher water vapor content compared to open land in the intermediate stage, which reduced the degree of non-equilibrium fractionation in throughfall, and the flow pathway enhanced in the later stage. Evaporation processes become more prominent as precipitation intensity weakens. The rainfall and throughfall were influenced by distinct meteorological factors in different precipitation events, and the role of the forest canopy varied across different precipitation periods. PEP was found to augment the intercept and slope of the linear relationship between the H-O isotopic composition of throughfall and rainfall. This pre-event effect also contributes to heightened fluctuations in the δ<sup>18</sup>O and d-excess values during subsequent precipitation events. The findings contribute to understanding water dynamics, vegetation interception, and mechanisms governing water input in forested areas during precipitation events, which provides valuable insights for analyzing factors influencing water movement in forest ecosystems. |
| first_indexed | 2024-03-10T23:55:55Z |
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| language | English |
| last_indexed | 2024-03-10T23:55:55Z |
| publishDate | 2023-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Forests |
| spelling | doaj.art-0afce33deca44058ba79d27027129ff42023-11-19T01:09:12ZengMDPI AGForests1999-49072023-08-01148160310.3390/f14081603Comparison of Intra-Event Characteristics of Hydrogen and Oxygen Stable Isotopes between Rainfall and Throughfall and the Effects of Pre-Event PrecipitationChengcheng Xia0Guodong Liu1Yuchuan Meng2Ke Chen3School of Geography and Tourism, Chongqing Normal University, Chongqing 401331, ChinaState Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, ChinaState Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, ChinaState Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, ChinaThe isotopic composition of precipitation provides valuable information about its source and transportation. However, raindrops interact with vegetation before reaching the earth’s surface, leading to isotopic changes in the infiltrating water. Comparing isotopic composition between rainfall and throughfall helps to understand canopy processes and their impact on isotopic variation. Based on observational data collected during the periods of July 2019, July–August 2020, and July–August 2021 in a planted forest located in the southwest monsoon region of China, this study examines hydrogen and oxygen isotopes in rainfall and throughfall at event and intra-event scales, and investigates the effects of pre-event precipitation (PEP) on the isotopic composition. The results indicate that during the initial stage of precipitation, δ<sup>18</sup>O was enriched in rainfall and it presented a dilution effect gradually, while the d-excess exhibits a low initial value followed by an increasing trend. The difference in δ<sup>18</sup>O between throughfall and rainfall initially increased and subsequently converged around 0, whereas the difference in d-excess experiences a decreasing phase, followed by an increasing phase, and finally a decreasing phase. Canopy interception led to a lag effect during the early stage of precipitation; the forest exhibited higher water vapor content compared to open land in the intermediate stage, which reduced the degree of non-equilibrium fractionation in throughfall, and the flow pathway enhanced in the later stage. Evaporation processes become more prominent as precipitation intensity weakens. The rainfall and throughfall were influenced by distinct meteorological factors in different precipitation events, and the role of the forest canopy varied across different precipitation periods. PEP was found to augment the intercept and slope of the linear relationship between the H-O isotopic composition of throughfall and rainfall. This pre-event effect also contributes to heightened fluctuations in the δ<sup>18</sup>O and d-excess values during subsequent precipitation events. The findings contribute to understanding water dynamics, vegetation interception, and mechanisms governing water input in forested areas during precipitation events, which provides valuable insights for analyzing factors influencing water movement in forest ecosystems.https://www.mdpi.com/1999-4907/14/8/1603forest ecosystemthroughfallcanopy interceptionpre-event precipitationisotopic composition |
| spellingShingle | Chengcheng Xia Guodong Liu Yuchuan Meng Ke Chen Comparison of Intra-Event Characteristics of Hydrogen and Oxygen Stable Isotopes between Rainfall and Throughfall and the Effects of Pre-Event Precipitation Forests forest ecosystem throughfall canopy interception pre-event precipitation isotopic composition |
| title | Comparison of Intra-Event Characteristics of Hydrogen and Oxygen Stable Isotopes between Rainfall and Throughfall and the Effects of Pre-Event Precipitation |
| title_full | Comparison of Intra-Event Characteristics of Hydrogen and Oxygen Stable Isotopes between Rainfall and Throughfall and the Effects of Pre-Event Precipitation |
| title_fullStr | Comparison of Intra-Event Characteristics of Hydrogen and Oxygen Stable Isotopes between Rainfall and Throughfall and the Effects of Pre-Event Precipitation |
| title_full_unstemmed | Comparison of Intra-Event Characteristics of Hydrogen and Oxygen Stable Isotopes between Rainfall and Throughfall and the Effects of Pre-Event Precipitation |
| title_short | Comparison of Intra-Event Characteristics of Hydrogen and Oxygen Stable Isotopes between Rainfall and Throughfall and the Effects of Pre-Event Precipitation |
| title_sort | comparison of intra event characteristics of hydrogen and oxygen stable isotopes between rainfall and throughfall and the effects of pre event precipitation |
| topic | forest ecosystem throughfall canopy interception pre-event precipitation isotopic composition |
| url | https://www.mdpi.com/1999-4907/14/8/1603 |
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