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Biogeosciences An interactive open-access journal of the European Geosciences Union
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Discussion papers | Copyright
https://doi.org/10.5194/bg-2017-447
© Author(s) 2017. This work is distributed under
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Research article 07 Nov 2017

Research article | 07 Nov 2017

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This discussion paper is a preprint. It has been under review for the journal Biogeosciences (BG). The manuscript was not accepted for further review after discussion.

Biogeochemical contrast between different latitudes and the effect of human activity on spatio-temporal carbon cycle change in Asian river systems

Tadanobu Nakayama Tadanobu Nakayama
  • Center for Global Environmental Research, National Institute for Environmental Studies, Tsukuba, 305-8506, Japan

Abstract. Recent research has shown inland water may play some role in carbon cycling, although the extent of its contribution has remained uncertain due to limited amount of reliable data available. In this study, the author applied an advanced model coupling eco-hydrology and biogeochemical cycle (NICE-BGC) to regional-continental scales, which incorporates complex coupling of hydrologic-carbon cycle and interplay between inorganic and organic carbon. The author evaluates latitudinal effect and human impact on hydrologic and carbon cycles between boreal Ob River, temperate Yangtze River, and subtropical Mekong River basins in Asia by using different resolutions of river network data. The model simulated more heterogenous distributions of water and carbon flux in the finer river network data in these regions, and helped to identify some hot spots on a regional scale. Then, the model was extended to continental scale at 1°×1° resolution with a time step of Δt=1 day to evaluate seasonal and diurnal variations in carbon flux parameters. The model result showed there is a seasonal variability of horizontal transport and vertical fluxes among boreal, temperate, and tropical regions and among each continent, which reflects seasonal variations of biologic and hydrologic processes there. The result showed CO2 evasion increases and sediment storage decreases in nighttime, particularly clearly seen temporarily in summer in Yangtze River, which implied some hot spots and hot moments in the day-night difference of vertical fluxes in regional scale. These results emphasize the important role of Asian river systems on global carbon cycle, and the further need to improve the resolution of simulation, to implement carbon observation network, and to apply satellite data in the higher-resolution.

Tadanobu Nakayama
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Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
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Interactive discussion
Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement
Tadanobu Nakayama
Tadanobu Nakayama
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This paper intends to investigate the ability of an advanced eco-hydrologic and biogeochemical coupling model NICE-BGC to estimate diurnal and seasonal variations of carbon flux budgets between different latitudes from various watersheds. Result implies shift of importance of aquatic metabolism and terrestrially derived carbon between daytime and nighttime. The result also helps to contribute on the further improvement in biogeochemical cycle along terrestrial-aquatic continuum.
This paper intends to investigate the ability of an advanced eco-hydrologic and biogeochemical...
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