Validation of Changing Water Origins over Indochina during the Withdrawal of the Asian Monsoon using Stable Isotopes
Validation of Changing Water Origins over Indochina during the Withdrawal of the Asian Monsoon using Stable Isotopes
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DOI：
10.2151/sola.2005-030
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发表时间：
2005
期刊：
影响因子：
1.9
通讯作者：
K. Ichiyanagi;K. Yoshimura;M. Yamanaka
中科院分区：
文献类型：
--
作者：
K. Ichiyanagi;K. Yoshimura;M. Yamanaka
2001年8月至11月，在泰国的三个测站观测了日降雨量和δ18O。用标记水传输模型估算了水源来源。随着亚洲季风从印度支那撤退，水源地的时空分布显示出明显的从印度洋向太平洋的过渡。提出了考虑水汽来源转换的印度支那地区亚洲季风退出日期的新定义。利用瑞利型同位素环流模型，在统计意义上重现了泰国三个站降水同位素的日变化。因此，模式中的大气水分平衡可以用这些降水同位素进行可靠的验证。然而，模拟的δ18O值显然被低估了，这可能是因为蒸发的同位素比率存在不确定性，而且在小尺度上缺乏同位素物理。
Daily rainfall and δ18O were observed from August to November 2001 at three stations in Thailand. Water origins were estimated using a tagged-water transport model. The temporal and spatial distributions of water origins showed a clear transition from the Indian Ocean to the Pacific Ocean as the Asian monsoon retreated from Indochina. A new definition of the withdrawal date of the Asian monsoon over Indochina is proposed that considers the transition of the origin of water vapor. The daily variability of precipitation isotopes at three stations in Thailand was reproduced at statistically significant levels using a Rayleigh-type isotope circulation model. Therefore, the atmospheric water balance in the model can be validated reliably with these precipitation isotopes. Nevertheless, the simulated δ18O values were obviously underestimated, perhaps because of uncertainties in the evaporating isotope ratios and the lack of isotope physics at small scales.