Riverine CO2 supersaturation and outgassing in a subtropical monsoonal mountainous area (Three Gorges Reservoir Region) of China

Li, Siyue; Ni, Maofei; Mao, Rong; Bush, Richard T

doi:10.1016/j.jhydrol.2018.01.057

Cited by 48 publications

(34 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…1) and the rest were TGR streams and small rivers. The study thus clearly shows distinct differences from a previous study (Li et al, 2018) through the contribution of specific new objectives and data supplements with wider significance. Our new contributions to the literature thus include (1) the determination and controls of k levels for small rivers and streams in subtropical areas of China and (2) new models developed in subtropical mountainous river networks.…”

Section: Introductioncontrasting

confidence: 71%

“…1250 mm with large intra-annual and interannual variability. About 75 % of the total annual rainfall is concentrated between April and September (Li et al, 2018).…”

Section: Study Areasmentioning

confidence: 99%

“…Rivers serve as a significant contributor of CO 2 to the atmosphere (Raymond et al, 2013;Cole et al, 2007;Li et al, 2012;Tranvik et al, 2009). As a consequence, accurate quantification of riverine CO 2 emissions is a key component to estimate net continental carbon (C) flux (Raymond et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…Generally, two methods are used to estimate CO 2 areal fluxes from the river system: direct measurements using floating chambers (FCs) and the indirect calculation of a thin boundary layer (TBL) model, which is dependent on the gas concentration gradient at the air-water interface and gas transfer velocity, k (Guerin et al, 2007;Xiao et al, 2014). Direct measurements are normally laborious, while the latter method is simple and thus preferred (Butman and Raymond, 2011;Lauerwald et al, 2015;Li et al, 2012Li et al, , 2013Ran et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…Models of k were further developed using hydraulic properties (i.e., flow velocity, water depth) by flux measurements with chambers and a TBL model. Our recent study preliminarily investigated pCO 2 and air-water CO 2 areal flux as well as their controls from fluvial networks in the Three Gorges Reservoir (TGR) area (Li et al, 2018). The past study was based on two fieldwork studies, and diffusive models from other rivers and/or regions were used.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Gas transfer velocities of CO<sub>2</sub> in subtropical monsoonal climate streams and small rivers

Mao

et al. 2019

Biogeosciences

Self Cite

View full text Add to dashboard Cite

Abstract. CO2 outgassing from rivers is a critical component for evaluating riverine carbon cycle, but it is poorly quantified largely due to limited measurements and modeling of gas transfer velocity in subtropical streams and rivers. We measured CO2 flux rates and calculated k and partial pressure (pCO2) in 60 river networks of the Three Gorges Reservoir (TGR) region, a typical area in the upper Yangtze River with monsoonal climate and mountainous terrain. The determined k600 (gas transfer velocity normalized to a Schmidt number of 600 (k600) at a temperature of 20 ∘C) value (48.4±53.2 cm h−1) showed large variability due to spatial variations in physical processes related to surface water turbulence. Our flux-derived k values using chambers were comparable with k values using the model derived from flow velocities based on a subset of data. Unlike in open waters, e.g., lakes, k600 is more pertinent to flow velocity and water depth in the studied river systems. Our results show that TGR river networks emitted approx. 0.69 to 0.71 Tg CO2 (1 Tg =1012 g) during the monsoon period using varying approaches such as chambers, derived k600 values and models. This study suggests that incorporating scale-appropriate k measurements into extensive pCO2 investigations is required to refine basin-wide carbon budgets in subtropical streams and small rivers. We concluded that the simple parameterization of k600 as a function of morphological characteristics is site specific for regions and watersheds and hence highly variable in rivers of the upper Yangtze. k600 models should be developed for stream studies to evaluate the contribution of these regions to atmospheric CO2.

show abstract

Section: Introductioncontrasting

confidence: 71%

“…1250 mm with large intra-annual and interannual variability. About 75 % of the total annual rainfall is concentrated between April and September (Li et al, 2018).…”

Section: Study Areasmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Gas transfer velocities of CO<sub>2</sub> in subtropical monsoonal climate streams and small rivers

Mao

et al. 2019

Biogeosciences

Self Cite

View full text Add to dashboard Cite

show abstract

Water seepage and retention in purple soil bunds on sloping farmland in the Three Gorges Reservoir area, China

et al. 2022

View full text Add to dashboard Cite

Soil bunds are a common land reconstruction practice in the Three Gorges Reservoir area of China, and play a key role in runoff regulation and soil conservation on cultivated hillslopes. This study investigated water movement pathways and retaining effects of soil bunds using water transport trajectory observations inferred from field dye tracing experiments. It was found that water infiltration in the bund was characterised by spatial heterogeneity in three dimensions. The stained area ratio (SAR) of the bund was much lower than that of the adjacent field at all depths. Dye patterns resembled inclined strips in the bund, and lateral seepage occurred mainly on the top of hard pan. SAR, stained path width (SPW) <20 mm, and stained path number (SPN) all decreased with increasing horizontal distance. The SPW <20 mm proportion and SAR both decreased according to a logarithmic function, while the changing trend of SPN followed a first‐order exponential decay. Three pathways of water movement in the bund could be distinguished, namely, vertical infiltration, lateral seepage and flow along the bund–bedrock interface. The primary water seepage channel in the bund was likely to be the bund–bedrock interface (accounting for around 80% of the total flow). These results provide preliminary realisation of water movement mechanisms in the purple soil bunds on sloping farmland and inform management options for bund stability maintenance.

show abstract

Dynamic controls on riverine pCO2 and CO2 outgassing in the Dry-hot Valley Region of Southwest China

Luo

2019

Aquat Sci

View full text Add to dashboard Cite

Riverine CO2 supersaturation and outgassing in a subtropical monsoonal mountainous area (Three Gorges Reservoir Region) of China

Cited by 48 publications

References 38 publications

Gas transfer velocities of CO<sub>2</sub> in subtropical monsoonal climate streams and small rivers

Gas transfer velocities of CO<sub>2</sub> in subtropical monsoonal climate streams and small rivers

Water seepage and retention in purple soil bunds on sloping farmland in the Three Gorges Reservoir area, China

Dynamic controls on riverine pCO2 and CO2 outgassing in the Dry-hot Valley Region of Southwest China

Contact Info

Product

Resources

About

Riverine CO2 supersaturation and outgassing in a subtropical monsoonal mountainous area (Three Gorges Reservoir Region) of China

Cited by 48 publications

References 38 publications

Gas transfer velocities of CO&lt;sub&gt;2&lt;/sub&gt; in subtropical monsoonal climate streams and small rivers

Gas transfer velocities of CO&lt;sub&gt;2&lt;/sub&gt; in subtropical monsoonal climate streams and small rivers

Water seepage and retention in purple soil bunds on sloping farmland in the Three Gorges Reservoir area, China

Dynamic controls on riverine pCO2 and CO2 outgassing in the Dry-hot Valley Region of Southwest China

Contact Info

Product

Resources

About

Gas transfer velocities of CO<sub>2</sub> in subtropical monsoonal climate streams and small rivers

Gas transfer velocities of CO<sub>2</sub> in subtropical monsoonal climate streams and small rivers