| 长沙近地面水汽中稳定同位素的监测与分析 |
| 摘要点击 2088 全文点击 968 投稿时间：2015-07-26 修订日期：2015-09-14 |
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| 中文关键词 大气水汽 降水 氢同位素 氧同位素 长沙地区 |
| 英文关键词 atmospheric water vapor precipitation hydrogen isotope oxygen isotope Changsha |
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| 中文摘要 |
| 根据长沙地区于2014年11月12日~2015年4月13日监测的大气水汽中δ18 O和δ2 H及观测的气象要素,分析了长沙近地面水汽中δ18 O和δ2 H变化特征以及与温度、 绝对湿度、 降水量的关系. 结果表明:①长沙大气水汽中δ18 O和δ2 H季节变化显著,在冬季表现为高值. 冬季大气水汽中δ18 O和δ2 H与绝对湿度存在正相关关系. δ18 O和δ2 H在监测期间存在较大波动,尤其是有降水事件发生时. 降水事件对长沙大气水汽中δ18 O和δ2 H的变化影响显著,水汽稳定同位素的低值与降水事件有关. ②不同天气条件下长沙大气水汽中δ18 O和δ2 H的日变化实质上与绝对湿度有关,而绝对湿度的大小又主要受控于局地的蒸散发和大气湍流的强度. 单次降水过程中大气水汽δ18 O和δ2 H存在显著的类似于降水中稳定同位素的"降雨量效应". ③长沙大气水汽中δ18 O和δ2 H总是低于降水中δ18 O和δ2 H,逐日变化基本一致,它们之间的平均差值分别为8.6‰和66.82‰. ④长沙冬半年大气水汽线方程为δ2 H=7.18δ18 O+10.58,水汽线的斜率和截距总是小于同时段大气水线的斜率和截距,春季水汽线的斜率和截距明显高于冬季水汽线的斜率和截距. |
| 英文摘要 |
| Based on the monitored atmospheric water vapor stable isotopes and observed meteorological elements at Changsha during the period from November 12, 2014 to April 13, 2015, the variations of water vapor stable isotopes and the relationships between isotope ratios and temperature, absolute humidity, precipitation amount were analyzed in this paper. The results indicated that: ① Seasonal variations of δ18 O and δ2 H in atmospheric water vapor at Changsha were remarkable, with high values in winter. δ18 O and δ2 H in atmospheric water vapor were positively correlated with absolute humidity in winter. There were some fluctuations of the δ18 O and δ2 H in atmospheric water vapor, especially when the precipitation events occurred. Precipitation events had a significant effect on the variations of δ18 O and δ2 H in atmospheric water vapor, and low values were often accompanied with precipitation events; ② Diurnal Variations of δ18 O and δ2 H in atmospheric water vapor had a close correlation with the atmospheric water vapor content, whereas the absolute humidity was mainly controlled by the strength of the local evapotranspiration and atmospheric turbulence. The "precipitation amount effect" was observed during the process of a single precipitation event; ③ Values of δ18 O and δ2 H in atmospheric water vapor were always lower than those of precipitation in Changsha, but he variation trends were completely consistent, the average difference values were 8.6 ‰ and 66.82 ‰, respectively; ④ The meteoric vapor line (MVL) in cold months was δ2 H=7.18δ18 O+10.58, the slope and intercept of MVL were always lower than those of MWL, and the slope and intercept of MVL in spring were significantly higher than those of winter. |
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