Daily δ18O and δD of precipitations from 2007 to 2009 in Guangzhou, South China: Implications for changes of moisture sources
Daily δ18O and δD of precipitations from 2007 to 2009 in Guangzhou, South China: Implications for changes of moisture sources
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DOI：
10.1016/j.jhydrol.2011.02.002
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发表时间：
2011-04
影响因子：
6.4
通讯作者：
Luhua Xie;G. Wei;W. Deng;Xiaoli Zhao
中科院分区：
文献类型：
--
作者：
Luhua Xie;G. Wei;W. Deng;Xiaoli Zhao
本文对2007 - 2009年广州地区降水中氢氧稳定同位素（δ 18 O和δ D）进行了分析。δ 18O与δ D的总相关关系为δ D =（8.46 ± 0.13）δ 18O+（15.0 ± 0.9）。δ 18 O和δ D在夏秋季节普遍出现负值，而在冬春季节出现负值或正值的情况较少。降水δ 18 O与温度、降水量呈显著负相关。每年回归线的变化可能是由于降水的水分来源的变化。冬季和早春的降水主要来自邻近海域的水汽或局地蒸发，而夏季风则从远海带来大量的水汽，气温较高，降水量较大。降水D-过剩的季节变化提供了更多的细节水分来源的变化。在冬季和早春较高的D-过量值估计对应于较小比例的远程水分，而在夏季和秋季较低的D-过量值对应于较大的远程夏季风输送的水分。这与特定时间段内单个等压后向轨迹的模式分析结果基本一致。研究结果表明，降水δ 18O和δ D以及洞穴沉积物和树木年轮中的δ 18O、植物源有机化合物和树木年轮中的δ D等相关古气候指标，目前尚不能单独指示温度或降水量的变化，而应是季风气候的综合指标。
Oxygen and hydrogen stable isotopes (δ18O and δD) in precipitation collected in every event from 2007 to 2009 in Guangzhou, South China, are presented in this paper. The total correlation between δ18O and δD is obtained as δD=(8.46±0.13) δ18O+(15.0±0.9). More negative δ18O and δD generally occur during summer and autumn, while less negative or even positive δ18O and δD occur during winter and spring. Significant negative correlations between precipitation δ18O and temperature, and between precipitation δ18O and precipitation amount are observed. Regression line changes from year to year are likely due to changes in moisture sources for the precipitation. The moisture contributed by adjacent seas or local evaporation account for the main precipitation during winter and early spring, while summer monsoon brings huge amounts of moisture from remote seas associated with higher temperature and larger precipitation amounts. Seasonal variations of the precipitation D-excess provide more details for changes in moisture sources. Higher D-excess values during winter and early spring are estimated to correspond to a lesser proportion of remote moisture, while lower D-excess values during summer and autumn correspond to larger remote moisture transported by summer monsoons. This generally agrees with the results of model analysis on single isobaric backward trajectories for air parcels during specific time periods. Results of this study imply that precipitation δ18O and δD, as well as some related paleoclimate proxies such as δ18O in speleothem and tree ring, and δD in plant-derived organic compounds and tree ring, currently cannot indicate changes in temperature or precipitation amount separately, but should be comprehensive proxies for monsoon climate.