Gas exchange rates for a first‐order stream determined with deliberate and natural tracers
Gas exchange rates for a first‐order stream determined with deliberate and natural tracers
复制标题
使用故意和自然示踪剂确定的一级流的气体交换率
DOI：
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发表时间：
1990
期刊：
影响因子：
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通讯作者：
J. Elwood
中科院分区：
文献类型：
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作者：
R. Wanninkhof;P. Mulholland;J. Elwood
Gas transfer velocities have been determined for a first-order stream by performing a 3-hour release of the volatile tracer sulfur hexafluoride, SF{sub 6}, and the nonvolatile tracer tritiated water, {sup 3}H{sub 2}O. The average gas transfer velocity for the 292-m reach was 29 cm/h which corresponds to a reaction coefficient for oxygen at 25C of 134 day{sup {minus}1}. Groundwater inflow along the stream was corrected for by measuring the downstream dilution of the {sup 3}H{sub 2}O spike. Downstream discharge increased from 0.5 L/s, 2 m downstream of the point of tracer release, to 19.3 L/s at a point 292 m downstream. As an alternative to using (radioactive) {sup 3}H{sub 2}O, the authors investigated the possibility of using natural radon, {sup 222}Rn, as a groundwater tag and using the variation of SF{sub 6} and {sup 222}Rn along the stream to determine gas exchange rates and groundwater inflow. The method yielded an average transfer velocity of 21 cm/h and underestimated the groundwater inflow by a factor of 3. This large discrepancy is attributed to a doubling of stream discharge between the time the stream was sampled for radon and the tracer experiment and the limited number of radon samples.
Gas transfer velocities have been determined for a first-order stream by performing a 3-hour release of the volatile tracer sulfur hexafluoride, SF{sub 6}, and the nonvolatile tracer tritiated water, {sup 3}H{sub 2}O. The average gas transfer velocity for the 292-m reach was 29 cm/h which corresponds to a reaction coefficient for oxygen at 25C of 134 day{sup {minus}1}. Groundwater inflow along the stream was corrected for by measuring the downstream dilution of the {sup 3}H{sub 2}O spike. Downstream discharge increased from 0.5 L/s, 2 m downstream of the point of tracer release, to 19.3 L/s at a point 292 m downstream. As an alternative to using (radioactive) {sup 3}H{sub 2}O, the authors investigated the possibility of using natural radon, {sup 222}Rn, as a groundwater tag and using the variation of SF{sub 6} and {sup 222}Rn along the stream to determine gas exchange rates and groundwater inflow. The method yielded an average transfer velocity of 21 cm/h and underestimated the groundwater inflow by a factor of 3. This large discrepancy is attributed to a doubling of stream discharge between the time the stream was sampled for radon and the tracer experiment and the limited number of radon samples.