河流水质采样策略与频率对氮磷负荷估算的影响  

Impact of sampling strategy and frequency of river water quality on nitrogen and phosphorus load estimation

作　　者：贾临东 胡宏祥 杜新忠 雷秋良[2] 张天鹏 刘宏斌[2] 蒋跃林 JIA Lin-dong;HU Hong-xiang;DU Xin-zhong;LEI Qiu-liang;ZHANG Tian-peng;LIU Hong-bin;JIANG Yue-lin(Anhui Province Key Laboratory of Farmland Ecological Conservation and Pollution Prevention,College of Resources and Environment,Anhui Agricultural University,Hefei 230036,China;State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China,Key Laboratory of Nonpoint Source Pollution Control,Ministry of Agriculture and Rural Affairs,Institute of Agricultural Resources and Regional Planning,Chinese Academy of Agricultural Sciences,Beijing 100081,China)

机构地区：[1]安徽农业大学资源与环境学院,农田生态保育与污染防控安徽省重点实验室,安徽合肥230036 [2]中国农业科学院农业资源与农业区划研究所,北方干旱半干旱耕地高效利用全国重点实验室,农业农村部面源污染控制重点实验室,北京100081

出　　处：《中国环境科学》2024年第4期2111-2118,共8页China Environmental Science

基　　金：宁夏联合基金资助项目(U20A20114);国家重点研发计划(2022YFC3204001);国家自然科学基金(U20A20114,42107076)。

摘　　要：为探究适合的流域水质监测频率与采样策略,提高氮磷污染物负荷估算的精度,基于云南省洱源县凤羽河流域2011~2013年间逐日流量与总氮､总磷浓度的每日数据,在7d/次,14d/次,21d/次,28d/次4种采样频率下设定了3种不同的采样情景(情景a:普通随机取样､情景b:随机取样的基础上增加降水量超过10mm的水样样品采集,情景c:随机取样的基础上增加降水量超过25mm的水样样品采集).基于采样频率与采样情景的组合,利用LOADEST模型估算的总氮与总磷负荷,并与逐日连续水量水质数据计算的实测值进行比较,评估了不同取样频率和取样情景下LOADEST模型的负荷估算精度.结果表明:在LOADEST模型的估算过程中,同种采样频率下,增加降雨时期的浓度数据将会提高LOADEST模型的模拟精度;在降雨事件期间进行加密采样,不仅加大了工作量,且增加的采样次数过多(如情景b)使总氮的RMSE值由1.92增至2.26,总磷的RMSE值由0.08增至0.19,高估氮磷负荷,模型模拟精度降低.在四种不同的采样频率下,情景c中总氮的RMSE值范围为1.92~2.07,总磷的RMSE值范围为0.06~0.13,均取得了该频率下最低的RMSE值,模型估算精度最高;从不同频率与采样情景对模型估算结果的影响来看,对总氮负荷估算结果(RMSE值范围为1.92~2.52)影响要大于总磷(RMSE值范围为0.06~0.18).其中,情景a与情景b的负荷估算结果精度随着采样频率降低而降低.情景c的估算结果受现有取样频率降低的影响不明显.本研究表明,在常规固定频率水质监测基础上结合气象预报适量增加降雨时的采样可在28d/次的较低取样频率下得到较高的氮磷负荷估算精度,符合我国各地区环境水质采样频率,可为相关研究的水质采样策略提供一定的参考作用.In order to explore suitable sampling frequency and strategy for water quality monitoring in the basin and improve the accuracy of nitrogen and phosphorus pollutant load estimation,nutrient loads were estimated based on daily data of daily discharge and total nitrogen and total phosphorus concentrations in Fengyu River Basin,Eryuan County,Yunnan Province from 2011 to 2013,under different scenarios.Specifically,three different sampling scenarios were set up(scenario a:general random sampling,scenario b:sampling water samples with more than 10mm of precipitation added on the basis of random sampling,and scenario c:sampling water samples with more than 25mm of precipitation added on the basis of random sampling)with sampling frequency ranging from weekly to nearly monthly.Based on the combination of different sampling frequencies and sampling scenarios,the accuracy of load estimations by LOADEST model is evaluated by comparing the total nitrogen and total phosphorus load estimated by LOADEST with the measured value calculated by daily continuous water quality and streamflow data.The results show that:adding the concentration data during the rainfall period will improve the simulation accuracy of LOADEST model under the same sampling frequency;sampling during rainfall events increases the frequency of sampling(such as scenario b),resulting in the RMSE of total nitrogen increasing from 1.92 to 2.26,and the RMSE value of total phosphorus increased from 0.08 to 0.19,which will affect the simulation accuracy of the model by overestimating the nitrogen and phosphorus load.Under four different sampling frequencies,the RMSE values of total nitrogen and total phosphorus in scenario c ranged from 1.92 to 2.07 and 0.06 to 0.13,obtained the lowest RMSE value and the highest accuracy of model estimation;different frequencies and sampling scenarios have greater impact on total nitrogen load estimation results(RMSE ranging from 1.92 to 2.52)than total phosphorus load estimation(RMSE ranging from 0.06 to 0.18).The accuracy of load

关 键 词：LOADEST模型 总氮 总磷 采样情景 负荷估算 

分 类 号：X522[环境科学与工程—环境工程]