Diurnal variation of stable isotopes in rainfall observed at Bengkulu for the YMC-Sumatra 2017
Diurnal variation of stable isotopes in rainfall observed at Bengkulu for the YMC-Sumatra 2017
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2017 年 YMC-苏门答腊岛在明古鲁观测到的降雨中稳定同位素的日变化
DOI：
10.1088/1755-1315/303/1/012008
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Takayuki Uesugi and Warjono
中科院分区：
文献类型：
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作者：
Kimpei Ichiyanagi;Rusmawan Suwarman;Halda Aditya Belgaman;Masahiro Tanoue;Takayuki Uesugi and Warjono
降水中稳定同位素的日变化及其控制因素知之甚少，特别是在热带地区。本研究调查了在印度尼西亚苏门答腊岛南部的本库鲁观测到的降雨中稳定同位素的日变化。从2017年12月1日至2018年1月15日，每隔6小时收集一次海洋大陆年（YMC-Sumatra 2017）的降雨样本。雨水的氧、氢同位素组成δ 18 O和δH分别为-15.1% o ~-1.8% o和-108.9% o ~-1.3% o，d-过剩值为1.9% o ~ 17.1% o。本库鲁观测结果表明，降水量的日变化不明显，但δ 18 O在清晨和下午较轻，中午前和夜间较重。δ 18 O在12月1-4日和21-24日连续降雨期间逐渐亏损。在这些时段中，早晨的降雨量远大于傍晚的降雨量，而在其他时段中，傍晚的降雨量大于早晨的降雨量。基于卫星获得的CMORPH数据，它被认为是上午雨和傍晚雨对应于周围海域的弱降雨和苏门答腊岛内陆地区的强降雨，分别。水汽来源的差异和早晚层状降水与对流降水的比值可能影响热带降水的同位素组成。
Diurnal variability of stable isotopes in precipitation and its controlling factors are poorly understood, especially in the tropics. This study investigated the diurnal variability of stable isotopes in rainfall observed at Bengkulu in southern Sumatra, Indonesia. Rainfall samples were collected at 6-h intervals from 1 December 2017 to 15 January 2018 for the Year of the Maritime Continent (YMC-Sumatra 2017). The oxygen and hydrogen isotopic compositions δ 18 O and δH) of the rainwater varied from–15.1% o to–1.8% o and from–108.9% o to–1.3% o, respectively, and the d-excess varied from 1.9% o to 17.1% o. The observations at Bengkulu revealed that diurnal variation in rainfall amount was not significant for the entire period; however, the δ 18 O was lighter in both the early morning and the afternoon and heavier before noon and overnight. The δ 18 O became gradually depleted in the periods of continuous rain that occurred during 1–4 and 21–24 December. The amount of morning rain was much greater than evening rain in these periods, whereas the amount of evening rain was greater than morning rain in other periods. Based on satellite-derived CMORPH data, it is assumed that morning rain and evening rain corresponded to weak rainfall over surrounding sea region and strong rainfall over inland regions of Sumatra, respectively. The differences in moisture source and ratio of stratiform/convective rain rate between morning and evening might affect the isotopic composition of rainfall in the tropics.