Journal of Geographical Sciences, Volume. 30, Issue 6, 881(2020)
A review of mass flux monitoring and estimation methods for biogeochemical interface processes in watersheds
Fig. 1. Mass flux associated with biogeochemical watershed interface processes driven by hydrological process (Numbers 1 through 4 correspond to sections 3.1 and 3.4 in this study, respectively. Different colored arrows represent different interface processes.)
Fig. 3. The intact core sediment incubation device (Wang
Fig. 4. Diagram of a high-resolution peeper device (Yang
Fig. 5. Sketch map of the intact sediment column flow-through system (Rydin, 2000; Xu
Table 1.
Seven methods for calculating river material flux (A-E are interpolation method, F and G are extrapolation methods) (Webb et al., 1997; Johnes, 2007)
View tableView in ArticleTable 1.
Seven methods for calculating river material flux (A-E are interpolation method, F and G are extrapolation methods) (Webb et al., 1997; Johnes, 2007)
No. Name Equation Description Applicability References A Interpolation methods ${\rm{Load}} = {\rm{K}}\left( {\mathop \sum \limits_{{\rm{i}} = 1}^{\rm{n}} \frac{{{{\rm{C}}_{\rm{i}}}}}{{\rm{n}}}} \right)\left( {\mathop \sum \limits_{{\rm{i}} = 1}^{\rm{n}} \frac{{{{\rm{Q}}_{\rm{i}}}}}{{\rm{n}}}} \right)$ K=conversion factor to take account of period of record Ci =instantaneous concentration associated with individual samples (mg l-1) Qi =instantaneous discharge at time of sampling (m3 s-1) ${{\rm{\bar Q}}_{\rm{r}}}$=mean discharge for period of record (m3 s-1) ${{\rm{\bar Q}}_{\rm{p}}}$=mean discharge for interval between samples (m3 s-1) n=number of samples Underestimate suspended sediment flux, but are relatively accurate Webb et al. , 1997B ${\rm{Load}} = {\rm{K}}\left( {\mathop \sum \limits_{{\rm{i}} = 1}^{\rm{n}} \frac{{{{\rm{C}}_{\rm{i}}}}}{{\rm{n}}}} \right){{\rm{\bar Q}}_{\rm{r}}}$ Webb et al. , 1997C ${\rm{Load}} = {\rm{K}}\mathop \sum \limits_{{\rm{i}} = 1}^{\rm{n}} \left( {\frac{{{{\rm{C}}_{\rm{i}}}{{\rm{Q}}_{\rm{i}}}}}{{\rm{n}}}} \right)$ Is suitable for pollutants whose flux is not closely associated to the flow rate Hao et al. , 2012Wang et al. , 2011D ${\rm{Load}} = {\rm{K}}\mathop \sum \limits_{{\rm{i}} = 1}^{\rm{n}} \left( {{{\rm{C}}_{\rm{i}}}{{{\rm{\bar Q}}}_{\rm{p}}}} \right)$ Are suitable for pollutants whose flux is closely associated with the flow rate Hao et al. , 2012E ${\rm{Load}} = \frac{{{\rm{K}}\mathop \sum \nolimits_{{\rm{i}} = 1}^{\rm{n}} \left( {{{\rm{C}}_{\rm{i}}}{{\rm{Q}}_{\rm{i}}}} \right)}}{{\mathop \sum \nolimits_{{\rm{i}} = 1}^{\rm{n}} {{\rm{Q}}_{\rm{i}}}}}{{\rm{\bar Q}}_{\rm{r}}}$ Zhang et al. , 2015Hao et al. , 2012F Interpolation method: Log-log rating ${{\rm{C}}_{\rm{i}}} = {\rm{aQ}}_{\rm{i}}^{\rm{b}}$ $e_i$=log($C_i$)-log($C_{ei}$) Log-log estimate of concentration is multiplied by CF2 to give ‘smeared’ estimate of concentration The estimation of suspended sediment flux using method F is relatively low Johnes et al. , 2007G Interpolation method: Smearing estimate ${\rm{CF}}2 = \frac{1}{{\rm{n}}}\mathop \sum \limits_{{\rm{i}} = 1}^{\rm{n}} {10^{{{\rm{e}}_{\rm{i}}}}}$
Table 2.
Mass flux monitoring and estimation methods for biogeochemical interface processes in watersheds and their respective advantages and disadvantages
View tableView in ArticleTable 2.
Mass flux monitoring and estimation methods for biogeochemical interface processes in watersheds and their respective advantages and disadvantages
Processes Interface Methods Advantages Disadvantages Dry deposition Atmosphere-plant-soil interface Wet collection method of dust collector Easy to operate;
Low costInconvenient sample transport;
Water easily overflows from the dust trap;
Prone to evaporate in summer and freeze in winterModel simulation method No particular need for sensitive sensors;
Long-term large-scale deposition flux estimationLow estimations accuracy Soil leaching Plant-soil-water interface In-situ plot method Small workload;
Low costTypical plots are difficult to select;
Not conducive to observing spatial differencesSoil tank simulation experimental method Easy to control experimental conditions and observe experimental results;
No need for long-term field observationsImpossible to exclude potential deviations from natural conditions Model simulation method Simulation results are more accurate Other parameters required River export Plant-soil-water interface Concentration-flow method Easy to understand;
Easy to calculateHigh data intensity requirements;
High cost of monitoringEmpirical model method Low data requirements Poor accuracy Mechanistic model method Good accuracy A large number of input parameters are required Sediment-water interface diffusion Soil-water interface/water-soil interface Static culture of the original column Consideration is given to the consistency between experimental conditions and real environmental conditions Material concentrations in overlying water cannot be kept constant;
Constrained by the sidewall effectConcentration diffusion model of interstitial water Good accuracy High data accuracy requirements;
Vulnerable to disturbancesFlow culture of the primary column Consideration is given to the consistency between experimental conditions and real environmental conditions;
Experimental conditions can be kept constantComplex operation;
Constrained by the sidewall effectFlume experiment Consideration is given to the consistency between experimental conditions and real environmental conditions;
The sidewall effect is well resolvedUndisturbed sediments are difficult to use as test material
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Yao LU, Yang GAO, Tiantian YANG. A review of mass flux monitoring and estimation methods for biogeochemical interface processes in watersheds[J]. Journal of Geographical Sciences, 2020, 30(6): 881
Received: Sep. 20, 2019
Accepted: Mar. 10, 2020
Published Online: Sep. 30, 2020
The Author Email: Yang GAO (gaoyang@igsnrr.ac.cn)
