根据四川卧龙自然保护区巴朗山流域皮条河河水的氢氧同位素组成分析,并与同期降水中氢氧同位素进行比较,研究了河水和降水氢氧同位素的变化规律.结果表明:(1)卧龙地区皮条河河水(δD~δ^18O性关系为:(δD = 3.888δ^18O45.614(R^2= 0.494,p<0.05,n=61).河水δD、δ^18O化幅度远小于降水δD、δ^18O的变化幅度.河水氘过量参数(d)与大气降水的氘过量参数(d)的季节变化趋势基本一致,冬春季氘过量参数(d)值较高,而夏秋季较低.(2)不同的季节,雪水和冰雪融水补给河水不同,雪水和冰雪融水补给河水主要发生在11月至翌年6月.(3)当降水量在0~10 mm时,降水δD、δ^18O的升高(或降低)引起河水δD、δ^18O高(或降低),这种影响在降水后第3天滞后发生.当降水量在10~20 mm时,降水δD、δ^18O升高或降低引起河水δD、δ^18O高或降低,这种影响在降水后第2天滞后发生.降水量在20~30 mm时,这种影响在降水后第1~2天发生.这表明河水δD、δ^18O响应时间与降水强度紧密相关,显示出发育良好的亚高山暗针叶林植被结构有利于土壤对降水的吸收、渗透和运移,从而调节和补充河川径流.
The authors investigated hydrogen and oxygen stable isotope (δD and δ^18O) of water in Pitiao River, and compared them with the δD and δ^18O of precipitation at Wolong Nature Reserve of Sichuan Province to explore the relationship between river water δD and δ^18O. It was found that the water δD was positively correlated with water δ^18O, namely, δD = 3.888 δ^18O -45.614 ( R^2 = 0.494,p 〈0.05,n =61 ). The variations of δ^18O and δD in the river water were much samller than those in the precipitation. The excess deuterium (d) in the river water and in the precipitation showed a very similar patterns of the seasonal variation,with the higher values in winter than in summer. Snow and snow-ice melting water discharging into the river varied with seasons and this process occurred mainly from November to next June. The response times of δ^18O and δD in the river water to precipitation depended on the intensity of precipitation. Given the intensities of precipitation at 0 - 10 mm, 10 -20 mm and 20 -30 mm, the response times of δD and δ^18O in the river water were 3 d, 2 d, and 1 - 2 d, respectively, after the occurrence of precipitation. This suggested that well-structured sub-alpine dark brown coniferous forests could improve rain water permeability into soil and facilitate water movement into the adjacent rivers, by which the forest regulated the run-off process and water discharge into the river.