| 三峡库区典型河流水-气界面CO2通量日变化观测及其影响因素分析 |
| 摘要点击 2287 全文点击 800 投稿时间：2018-03-11 修订日期：2018-04-19 |
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| 中文关键词 CO2释放 水-气界面 日变化 季节变化 环境因子 |
| 英文关键词 CO2 emission water-air interface daily change seasonal change environmental factors |
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| 中文摘要 |
| 为研究河流水-气界面CO2通量的季节和日变化特征；于2016年7月15~17日以及2017年11月4~6日对三峡库区嘉陵江支流竹溪河进行定点定时采集表层水样，并同步监测关键环境因子，采用亨利定律结合薄边界层模型计算其水-气界面CO2通量F（CO2）.结果表明，竹溪河表层水CO2分压p（CO2）及界面CO2脱气通量呈现出显著的日间和季节变化，以及明显的日内变化特征：在上午09：00前后达到释放高峰，随后波动下降；水-气界面CO2通量日间均值分别为（100.9±31.6）、（78.6±12.1）、（83.9±29.7）、（137.5±42.1）、（147.6±34.0）、（132.4±21.7）mmol·（m2·d）-1；并表现出夏季表层水体CO2释放通量明显低于秋季，其均值分别为（87.8±27.5）mmol·（m2·d）-1和（139.2±34.0）mmol·（m2·d）-1；总体表现出大气CO2源的特征.竹溪河p（CO2）和F（CO2）受到诸多环境因子的影响，相关分析表明，pH、碱度、水温和气温是主要环境影响因子，CO2释放通量可以用pH和碱度预测. |
| 英文摘要 |
| Diurnal and seasonal characterization of CO2 partial pressure p(CO2) and CO2 areal flux F(CO2) at the water-air interface in an anthropogenic river in the Three Gorges Reservoir area was studied. A tributary of the Jialing River in Chongqing Municipality was chosen, and daily and seasonal samples were taken in summer and autumn, focusing on riverine p(CO2), F(CO2), and their associated controls. Henry's law combined with the thin boundary layer model was adopted to estimate the CO2 flux via the water-air interface. The results indicated that F(CO2) was not high on average, namely (87.8±27.5) mmol·(m2·d)-1 and (139.2±34.0) mmol·(m2·d)-1 in summer and autumn, respectively. The water-air interface F(CO2) showed significant hourly, daily, and seasonal variations. CO2 release peaked around 09:00 and then slightly decreased. We also found that pH, alkalinity, water, and temperature were significantly related to p(CO2) and F(CO2), whereas pH and alkalinity were the best predictors of F(CO2). This study aids understanding of the impacts of urbanization on CO2 emissions in the rivers and helps to re-evaluate local riverine CO2 budgets. |
