Seasonal and downstream alterations of dissolved organic matter and dissolved inorganic ions in a human-impacted mountainous tributary of the Yellow River, China

Abstract This is the first part of a study focusing on evaluating the performance of the Noah land surface model (LSM) in simulating surface water and energy budgets for the high-elevation source region of the Yellow River (SRYR). A comprehensive dataset is utilized that includes in situ micrometeorological and profile soil moisture and temperature measurements as well as laboratory soil property measurements of samples collected across the SRYR. Here, the simulation of soil water flow is investigated, while Part II concentrates on the surface heat flux and soil temperature simulations. Three augmentations are proposed: 1) to include the effect of organic matter on soil hydraulic parameterization via the additivity hypothesis, 2) to implement the saturated hydraulic conductivity as an exponentially decaying function with soil depth, and 3) to modify the vertical root distribution to represent the Tibetan conditions characterized by an abundance of roots in the topsoil. The diffusivity form of Richards’ equation is further revised to allow for the simulation of soil water flow across soil layers with different hydraulic properties. Usage of organic matter for calculating the porosity and soil suction improves the agreement between the estimates and laboratory measurements, and the exponential function together with the Kozeny–Carman equation best describes the in situ . Through implementation of the modified hydraulic parameterization alone, the soil moisture underestimation in the upper soil layer under wet conditions is resolved, while the soil moisture profile dynamics are better captured by also including the modified root distribution.

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Augmentations to the Noah Model Physics for Application to the Yellow River Source Area. Part II: Turbulent Heat Fluxes and Soil Heat Transport

Journal of Hydrometeorology ◽

10.1175/jhm-d-14-0199.1 ◽

2015 ◽

Vol 16 (6) ◽

pp. 2677-2694 ◽

Cited By ~ 22

Author(s):

Donghai Zheng ◽

Rogier van der Velde ◽

Zhongbo Su ◽

Xin Wang ◽

Jun Wen ◽

...

Keyword(s):

Heat Flux ◽

Organic Matter ◽

Surface Temperature ◽

Heat Transport ◽

Yellow River ◽

Turbulent Heat Flux ◽

Heat Fluxes ◽

The Yellow River ◽

Turbulent Heat ◽

Turbulent Heat Fluxes

Abstract This is the second part of a study on the assessment of the Noah land surface model (LSM) in simulating surface water and energy budgets in the high-elevation source region of the Yellow River. Here, there is a focus on turbulent heat fluxes and heat transport through the soil column during the monsoon season, whereas the first part of this study deals with the soil water flow. Four augmentations are studied for mitigating the overestimation of turbulent heat flux and underestimation of soil temperature measurements: 1) the muting effect of vegetation on the thermal heat conductivity is removed from the transport of heat from the first to the second soil layer, 2) the exponential decay factor imposed on is calculated using the ratio of the leaf area index (LAI) over the green vegetation fraction (GVF), 3) Zilitinkevich’s empirical coefficient for turbulent heat transport is computed as a function of the momentum roughness length , and 4) the impact of organic matter is considered in the parameterization of the thermal heat properties. Although usage of organic matter for calculating improves the correspondence between the estimates and laboratory measurements of heat conductivities, it is shown to have a relatively small impact on the Noah LSM performance even for large organic matter contents. In contrast, the removal of the muting effect of vegetation on and the parameterization of greatly enhances the soil temperature profile simulations, whereas turbulent heat flux and surface temperature computations mostly benefit from the modified formulation. Further, the nighttime surface temperature overestimation is resolved from a coupled land–atmosphere perspective.

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Dissolved Organic Matter and Inorganic Ions in a Central Himalayan Glacier—Insights into Chemical Composition and Atmospheric Sources

Environmental Science & Technology ◽

10.1021/es4009882 ◽

2013 ◽

Vol 47 (12) ◽

pp. 6181-6188 ◽

Cited By ~ 35

Author(s):

Jianzhong Xu ◽

Qi Zhang ◽

Xiangying Li ◽

Xinlei Ge ◽

Cunde Xiao ◽

...

Keyword(s):

Organic Matter ◽

Chemical Composition ◽

Dissolved Organic Matter ◽

Inorganic Ions ◽

Himalayan Glacier

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Comparison of macrobenthic communities between the invasive Spartina alterniflora and native Suaeda glauca habitats in the Yellow River Delta

10.21203/rs.3.rs-734847/v1 ◽

2021 ◽

Author(s):

Qiuying Han ◽

Qingxi Han ◽

Yujue Wang ◽

Dongyan Liu

Keyword(s):

Organic Matter ◽

Functional Groups ◽

Spartina Alterniflora ◽

Seasonal Changes ◽

Yellow River ◽

Yellow River Delta ◽

The Yellow River ◽

The Yellow River Delta ◽

Macrobenthic Communities ◽

Suaeda Glauca

Abstract Salt marsh habitats in estuaries play important roles in species compositions and macrobenthos abundances. Here, the macrobenthic communities and environmental conditions in two habitats, which are dominated by the invasive species Spartina alterniflora (SA) and native species Suaeda glauca (SG), in the Yellow River Delta were studied to assess habitat function. The seasonal data showed that the species diversity and abundance of macrobenthos in the SA habitat were much higher than those in the SG habitat. The functional groups in the former showed significant seasonal changes and shifted from polychaeta (68%) in spring to mollusca (97%) in autumn, but in the latter, it was dominated by crustacea (63-86%), mollusca (1-25%) and polychaeta (9-13%), and only mollusca exhibited obvious seasonal changes. The sediments in the SA habitat contained richer organic matter contents and exhibited higher Chl- a concentrations than those in the SG habitat, although the grain sizes were coarser in the SA habitat. At the seasonal scale, macrobenthos in the SA habitat displayed significant negative correlations with salinity and organic matter. The results indicated that the macrobenthos functional groups in the SA habitat were simpler and more sensitive to environmental changes than those in the SG habitat. The vegetation structures may give rise to the differences in macrobenthos distributions in both habitats, which need to be further observed and explored.

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