基于流量和溶存浓度的河流水系氧化亚氮释放量估算  

Estimation of Nitrous Oxide Emission from River System Based on Water Discharge and Dissolved Nitrous Oxide Concentration

作　　者：李冰清 胡敏鹏 王铭烽 张育福 吴昊[1,2] 周佳[1,2] 吴锴彬 戴之舟[1,2] 陈丁江 LI Bing-qing;HU Min-peng;WANG Ming-feng;ZHANG Yu-fu;WU Hao;ZHOU Jia;WU Kai-bin;DAI Zhi-zhou;CHEN Ding-jiang(College of Environmental&Resource Sciences,Zhejiang University,Hangzhou 310058,China;Ministry of Education Key Laboratory of Environment Remediation and Ecological Health,Zhejiang University,Hangzhou 310058,China;Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]浙江大学环境与资源学院,杭州310058 [2]浙江大学环境修复与生态健康教育部重点实验室,杭州310058 [3]浙江大学浙江省亚热带土壤与植物营养重点实验室,杭州310058

出　　处：《环境科学》2022年第1期369-376,共8页Environmental Science

基　　金：国家自然科学基金项目(41877465);浙江省杰出青年基金项目(LR19D010002)。

摘　　要：随着活性氮污染负荷增加,河流已成为许多地区重要的氧化亚氮(N_(2)O)释放源.由于许多研究的监测数据较少以及现行方法存在中间参数估算困难和难以表达时空变异性等不足,估算河流水系N_(2)O释放量尚存在较大不确定性.以浙江永安溪水系为研究对象,基于2016-06~2019-07对10个监测断面的逐月监测结果,分析了河流N_(2)O溶存浓度[ρ(N_(2)O)]和释放通量的时空分布特征及其影响因素,建立了河流N_(2)O释放通量估算的二元回归模型.结果表明,永安溪水系ρ(N_(2)O)(0.03~2.14μg·L;)和释放通量[1.32~82.79μg·(m^(2)·h)^(-1)]呈现1~2个数量级的时空变异性.河流ρ(N_(2)O)的时空变化主要受硝态氮、氨氮和可溶性有机碳无机氮质量比影响,而N_(2)O释放通量主要受流量和ρ(N_(2)O)影响.基于河流流量和ρ(N_(2)O)建立的二元回归模型能解释河流N_(2)O释放通量90%的时空变异性,具有较高精度.模型估算的整个永安溪水系N_(2)O释放量为3.67 t·a^(-1),其中29%来源于干流和71%来源于支流.IPCC(联合国政府间气候变化专门委员会)的排放因子推荐值方法会高估受人类活动影响小的河流N_(2)O释放量,但会低估受人类活动影响大的河流N_(2)O释放量.研究结果推进了对河流水系N_(2)O释放规律的定量认识,为较准确地估算河流水系N_(2)O释放量提供了借鉴方法.Due to increasing active nitrogen pollution loads, river systems have become an important source of nitrous oxide(N_(2)O) in many areas. Due to the lack of monitoring data in many studies as well as the difficulty in estimating intermediate parameters and expressing temporal-spatial variability in current methods, a high level of uncertainty remains in the estimates of riverine N_(2)O emission quantity. Based on the monthly monitoring efforts conducted for 10 sampling sites across the Yonganxi River system in Zhejiang Province from June 2016 to July 2019, the temporal and spatial dynamics of riverine N_(2)O dissolved concentrations ρ(N_(2)O), N_(2)O fluxes, and their influencing factors were addressed. A multiple regression model was then developed for predicating riverine N_(2)O emission flux to estimate annual N_(2)O emission quantity for the entire river system. The results indicated that observed riverine ρ(N_(2)O)(0.03-2.14 μg·L;) and the N_(2)O fluxes [1.32-82.79 μg·(m^(2)·h)^(-1)] varied by 1-2 orders of magnitude of temporal-spatial variability. The temporal and spatial variability of ρ(N_(2)O) were mainly influenced by the concentrations of nitrate, ammonia, and dissolved organic carbon, whereas the N_(2)O emission fluxes were mainly affected by river water discharges and ρ(N_(2)O). A multiple regression model that incorporates variables of river water discharge and ρ(N_(2)O) could explain 90% of the variability in riverine N_(2)O emission fluxes and has high accuracy. The model estimated N_(2)O emission quantity from the entire Yonganxi River system of 3.67 t·a^(-1), with 29% from the main stream and 71% from the tributaries. The IPCC default emission factor method might greatly overestimate and underestimate N_(2)O emission quantities for rivers impacted by low and high pressures of human activities, respectively. This study advances our quantitative understanding of N_(2)O emission for the entire river system and provides a reference method for estimating riverine N_(2)O emission with more

关 键 词：河流 氧化亚氮 溶存浓度 释放通量 模型 

分 类 号：X16[环境科学与工程—环境科学]