Traceable components of terrestrial carbon storage capacity in biogeochemical models

2013 ◽  
Vol 19 (7) ◽  
pp. 2104-2116 ◽  
Author(s):  
Jianyang Xia ◽  
Yiqi Luo ◽  
Ying-Ping Wang ◽  
Oleksandra Hararuk
Keyword(s):  
Carbon Storage ◽  
Storage Capacity ◽  
Terrestrial Carbon ◽  
Biogeochemical Models

scholarly journals A semi-analytical solution to accelerate spin-up of a coupled carbon and nitrogen land model to steady state

2012 ◽  
Vol 5 (5) ◽  
pp. 1259-1271 ◽  
Author(s):  
J. Y. Xia ◽  
Y. Q. Luo ◽  
Y.-P. Wang ◽  
E. S. Weng ◽  
O. Hararuk
Keyword(s):  
Steady State ◽  
Analytical Solution ◽  
Carbon Storage ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Storage Capacity ◽  
Computational Time ◽  
Ecosystem Carbon ◽  
Biogeochemical Models ◽  
Pool Sizes

Abstract. The spin-up of land models to steady state of coupled carbon–nitrogen processes is computationally so costly that it becomes a bottleneck issue for global analysis. In this study, we introduced a semi-analytical solution (SAS) for the spin-up issue. SAS is fundamentally based on the analytic solution to a set of equations that describe carbon transfers within ecosystems over time. SAS is implemented by three steps: (1) having an initial spin-up with prior pool-size values until net primary productivity (NPP) reaches stabilization, (2) calculating quasi-steady-state pool sizes by letting fluxes of the equations equal zero, and (3) having a final spin-up to meet the criterion of steady state. Step 2 is enabled by averaged time-varying variables over one period of repeated driving forcings. SAS was applied to both site-level and global scale spin-up of the Australian Community Atmosphere Biosphere Land Exchange (CABLE) model. For the carbon-cycle-only simulations, SAS saved 95.7% and 92.4% of computational time for site-level and global spin-up, respectively, in comparison with the traditional method (a long-term iterative simulation to achieve the steady states of variables). For the carbon–nitrogen coupled simulations, SAS reduced computational cost by 84.5% and 86.6% for site-level and global spin-up, respectively. The estimated steady-state pool sizes represent the ecosystem carbon storage capacity, which was 12.1 kg C m−2 with the coupled carbon–nitrogen global model, 14.6% lower than that with the carbon-only model. The nitrogen down-regulation in modeled carbon storage is partly due to the 4.6% decrease in carbon influx (i.e., net primary productivity) and partly due to the 10.5% reduction in residence times. This steady-state analysis accelerated by the SAS method can facilitate comparative studies of structural differences in determining the ecosystem carbon storage capacity among biogeochemical models. Overall, the computational efficiency of SAS potentially permits many global analyses that are impossible with the traditional spin-up methods, such as ensemble analysis of land models against parameter variations.

scholarly journals A semi-analytical solution to accelerate spin-up of a coupled carbon and nitrogen land model to steady state

2012 ◽  
Vol 5 (2) ◽  
pp. 803-836 ◽  
Author(s):  
J. Xia ◽  
Y. Luo ◽  
Y.-P. Wang ◽  
E. Weng ◽  
O. Hararuk
Keyword(s):  
Steady State ◽  
Analytical Solution ◽  
Carbon Storage ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Storage Capacity ◽  
Computational Time ◽  
Ecosystem Carbon ◽  
Biogeochemical Models ◽  
Pool Sizes

Abstract. The spin-up of land models to steady state of coupled carbon-nitrogen processes is computationally so costly that it becomes a~bottleneck issue for global analysis. In this study, we introduced a semi-analytical solution (SAS) for the spin-up issue. SAS is fundamentally based on the analytic solution to a set of equations that describe carbon transfers within ecosystems over time. SAS is implemented by three steps: (1) having an initial spin-up with prior pool-size values until net primary productivity (NPP) reaches steady state, (2) calculating quasi steady-state pool sizes by letting fluxes of the equations equal zero, and (3) having a final spin-up to meet the criterion of steady state. Step 2 is enabled by averaged time-varying variables over one period of repeated driving forcings. SAS was applied to both site-level and global scale spin-up of the Australian Community Atmosphere Biosphere Land Exchange (CABLE) model. For the carbon-cycle-only simulations, SAS saved 95.7% and 92.4% of computational time for site-level and global spin-up, respectively, in comparison with the traditional method. For the carbon-nitrogen-coupled simulations, SAS reduced computational cost by 84.5% and 86.6% for site-level and global spin-up, respectively. The estimated steady-state pool sizes represent the ecosystem carbon storage capacity, which was 12.1 kg C m−2 with the coupled carbon-nitrogen global model, 14.6% lower than that with the carbon-only model. The nitrogen down-regulation in modeled carbon storage is partly due to the 4.6% decrease in carbon influx (i.e., net primary productivity) and partly due to the 10.5% reduction in residence times. This steady-state analysis accelerated by the SAS method can facilitate comparative studies of structural differences in determining the ecosystem carbon storage capacity among biogeochemical models. Overall, the computational efficiency of SAS potentially permits many global analyses that are impossible with the traditional spin-up methods, such as ensemble analysis of land models against parameter variations.

Water and carbon storage capacity inIsolatocereus dumortieri(Cactaceae) in an intertropical semiarid zone in Mexico

2015 ◽  
Vol 31 (3) ◽  
pp. 240-243 ◽  
Author(s):  
Numa P. Pavón ◽  
Christian O. Ayala ◽  
Ana Paola Martínez-Falcón
Keyword(s):  
Carbon Storage ◽  
Storage Capacity ◽  
Semiarid Zone

scholarly journals Glacial – interglacial atmospheric CO<sub>2</sub> change: a simple "hypsometric effect" on deep-ocean carbon sequestration?

2006 ◽  
Vol 2 (5) ◽  
pp. 711-743 ◽  
Author(s):  
L. C. Skinner
Keyword(s):  
Carbon Sequestration ◽  
Carbon Storage ◽  
Ocean Circulation ◽  
Deep Water ◽  
Deep Sea ◽  
Storage Capacity ◽  
Deep Ocean ◽  
Contributing Factors ◽  
Carbon Reservoir ◽  
Ocean Carbon

Abstract. Given the magnitude and dynamism of the deep marine carbon reservoir, it is almost certain that past glacial – interglacial fluctuations in atmospheric CO2 have relied at least in part on changes in the carbon storage capacity of the deep sea. To date, physical ocean circulation mechanisms that have been proposed as viable explanations for glacial – interglacial CO2 change have focussed almost exclusively on dynamical or kinetic processes. Here, a simple mechanism is proposed for increasing the carbon storage capacity of the deep sea that operates via changes in the volume of southern-sourced deep-water filling the ocean basins, as dictated by the hypsometry of the ocean floor. It is proposed that a water-mass that occupies more than the bottom 3 km of the ocean will essentially determine the carbon content of the marine reservoir. Hence by filling this interval with southern-sourced deep-water (enriched in dissolved CO2 due to its particular mode of formation) the amount of carbon sequestered in the deep sea may be greatly increased. A simple box-model is used to test this hypothesis, and to investigate its implications. It is suggested that up to 70% of the observed glacial – interglacial CO2 change might be explained by the replacement of northern-sourced deep-water below 2.5 km water depth by its southern counterpart. Most importantly, it is found that an increase in the volume of southern-sourced deep-water allows glacial CO2 levels to be simulated easily with only modest changes in Southern Ocean biological export or overturning. If incorporated into the list of contributing factors to marine carbon sequestration, this mechanism may help to significantly reduce the "deficit" of explained glacial – interglacial CO2 change.

scholarly journals Terrestrial biosphere changes over the last 120 kyr

2016 ◽  
Vol 12 (1) ◽  
pp. 51-73 ◽  
Author(s):  
B. A. A. Hoogakker ◽  
R. S. Smith ◽  
J. S. Singarayer ◽  
R. Marchant ◽  
I. C. Prentice ◽  
...  
Keyword(s):  
Carbon Storage ◽  
Temperate Forest ◽  
Large Scale ◽  
Net Primary Productivity ◽  
Carbon Isotopic Composition ◽  
Pollen Data ◽  
Terrestrial Carbon ◽  
Terrestrial Biosphere ◽  
Last Glacial ◽  
The Last Glacial

Abstract. A new global synthesis and biomization of long (> 40 kyr) pollen-data records is presented and used with simulations from the HadCM3 and FAMOUS climate models and the BIOME4 vegetation model to analyse the dynamics of the global terrestrial biosphere and carbon storage over the last glacial–interglacial cycle. Simulated biome distributions using BIOME4 driven by HadCM3 and FAMOUS at the global scale over time generally agree well with those inferred from pollen data. Global average areas of grassland and dry shrubland, desert, and tundra biomes show large-scale increases during the Last Glacial Maximum, between ca. 64 and 74 ka BP and cool substages of Marine Isotope Stage 5, at the expense of the tropical forest, warm-temperate forest, and temperate forest biomes. These changes are reflected in BIOME4 simulations of global net primary productivity, showing good agreement between the two models. Such changes are likely to affect terrestrial carbon storage, which in turn influences the stable carbon isotopic composition of seawater as terrestrial carbon is depleted in 13C.

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