scholarly journals Supplementary material to "Evaluation of carbonyl sulfide biosphere exchange in the Simple Biosphere Model (SiB4)"

2021 ◽  
Author(s):  
Linda M. J. Kooijmans ◽  
Ara Cho ◽  
Jin Ma ◽  
Aleya Kaushik ◽  
Katherine D. Haynes ◽  
...  
Keyword(s):  
Carbonyl Sulfide ◽  
Supplementary Material ◽  
Biosphere Model

scholarly journals Supplementary material to "Canopy uptake dominates nighttime carbonyl sulfide fluxes in a boreal forest"

2017 ◽  
Author(s):  
Linda M. J. Kooijmans ◽  
Kadmiel Maseyk ◽  
Ulli Seibt ◽  
Wu Sun ◽  
Timo Vesala ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Carbonyl Sulfide ◽  
Canopy Uptake ◽  
Supplementary Material

Carbonyl sulfide reflections of leaf and ecosystem processes in a tropical rainforest under controlled drought

2020 ◽  
Author(s):  
Laura Meredith ◽  
Róisín Commane ◽  
Ian Baker ◽  
Juliana Gil-Loaiza ◽  
Joost van Haren ◽  
...  
Keyword(s):  
Tropical Rainforest ◽  
Carbonyl Sulfide ◽  
Ecosystem Processes ◽  
Isotopic Tracers ◽  
Biosphere 2 ◽  
Experimental Systems ◽  
Water Cycling ◽  
Need To Evaluate ◽  
Leaf Level ◽  
Biosphere Model

<p>A promising tracer for partitioning the global balance of CO<sub>2</sub> is carbonyl sulfide (COS or OCS), a trace gas with leaf-level mechanisms shared with carbon dioxide (CO<sub>2</sub>) and water (H<sub>2</sub>O). COS is therefore used to derive insights into photosynthesis and transpiration at ecosystem to global scales. However, it remains unclear whether COS reflects photosynthesis or stomatal conductance most strongly, as its leaf biochemical and physical processes are not perfectly analogous to either CO<sub>2</sub> or H<sub>2</sub>O. There is therefore a need to evaluate the models that encapsulate our current understanding of leaf and soil COS fluxes and predictions of carbon and water cycling against independent constraints in tractable experimental systems.</p><p>In this study, we measured ecosystem, leaf, and soil fluxes of COS in the model Biosphere 2 (B2) Tropical Rainforest across a controlled whole ecosystem drought manipulation. We simultaneously, measured the stable isotopes of CO<sub>2</sub>, H<sub>2</sub>O, and their isotopes (<sup>13</sup>C-CO<sub>2</sub>, <sup>18</sup>O-CO<sub>2</sub>, <sup>2</sup>H-H<sub>2</sub>O, <sup>18</sup>O-H<sub>2</sub>O) on atmosphere, leaf, and soil measurement streams connected to atmospheric towers, leaf chambers, and soil flux chambers. During the B2 Water, Atmosphere, and Life Dynamics (B2 WALD) campaign, the enclosed ecosystem received no rain for 66 days and was first rewet at depth (2-4 m) at 54 days. Here, we compare COS fluxes to simultaneous and independent measurements of GPP and transpiration from the leaf to ecosystem scales across ecosystem control, drought, and recovery. We further integrate COS measurements with the aforementioned isotopic tracers of carbon and water cycling into the Simple Biosphere Model (SiB3). Our goal is to explore the strengths and limitations of COS as a tracer of ecosystem processes dynamically responding to severe and controlled ecosystem drought.</p>

Validation and development of carbonyl sulfide biosphere exchange in the Simple Biosphere Model (SiB4)

2021 ◽  
Author(s):  
Linda Kooijmans ◽  
Ara Cho ◽  
Jin Ma ◽  
Ian Baker ◽  
Aleya Kaushik ◽  
...  
Keyword(s):  
Carbonyl Sulfide ◽  
Original Model ◽  
Seasonal Cycles ◽  
Large Role ◽  
Tropical Regions ◽  
Sources And Sinks ◽  
Mixing Ratios ◽  
Closing The Gap ◽  
Biosphere Model ◽  
Good Agreement

<p>The uptake of carbonyl sulfide (COS) in plants is strongly dependent on stomatal conductance. The COS uptake is therefore strongly related to the photosynthetic uptake of CO<sub>2</sub> in plants. As there is a gap in the COS budget with a source missing (or an overestimated sink) in tropical regions, this asks for evaluation of all sources and sinks of COS to be able to apply COS as a photosynthetic tracer. The COS uptake by vegetation and soil is simulated by the Simple Biosphere Model (SiB4) but it has not been validated against ecosystem and vegetation fluxes across different biomes. We evaluated the SiB4 COS biosphere flux with observations and updated it with the latest insights, with the aim to get the best possible estimate of the global COS biosphere sink. Overall, we find good agreement of simulated diurnal and seasonal cycles of COS ecosystem fluxes with flux observations made over grasslands, evergreen needleleaf forest and deciduous broadleaf forests over Europe and Northern America. We improved the simulations of COS soil exchange with the implementation of the Ogee et al. (2016) soil model such that SiB4 is now capable of simulating COS emissions from soils. We found that accounting for varying COS mixing ratios (retrieved from an inversion by the TM5-4DVAR model) plays a large role in determining the global COS biosphere sink. With these modifications to the model, we find an average underestimation of the COS biosphere flux of 11 % compared to observations. Furthermore, our model modifications caused a drop in the global COS biosphere sink from 967 Gg S yr-1 in the original model to 788 Gg S yr-1 in the updated version. The largest drop in fluxes is over the tropical regions, mostly driven by lower COS mixing ratios and contributes towards closing the gap in the COS budget. However, given the underestimation of COS uptake in the boreal and temperature regions, it is unlikely that the remaining gap in the COS budget is caused by an overestimated tropical biosphere sink.   </p><p> </p>

scholarly journals Evaluation of carbonyl sulfide biosphere exchange in the Simple Biosphere Model (SiB4)

2021 ◽  
Vol 18 (24) ◽  
pp. 6547-6565
Author(s):  
Linda M. J. Kooijmans ◽  
Ara Cho ◽  
Jin Ma ◽  
Aleya Kaushik ◽  
Katherine D. Haynes ◽  
...  
Keyword(s):  
Mole Fraction ◽  
Mechanistic Model ◽  
Carbonyl Sulfide ◽  
Growing Season ◽  
Global Scale ◽  
Terrestrial Plants ◽  
Large Variability ◽  
Accurate Representation ◽  
High Productivity ◽  
Biosphere Model

Abstract. The uptake of carbonyl sulfide (COS) by terrestrial plants is linked to photosynthetic uptake of CO2 as these gases partly share the same uptake pathway. Applying COS as a photosynthesis tracer in models requires an accurate representation of biosphere COS fluxes, but these models have not been extensively evaluated against field observations of COS fluxes. In this paper, the COS flux as simulated by the Simple Biosphere Model, version 4 (SiB4), is updated with the latest mechanistic insights and evaluated with site observations from different biomes: one evergreen needleleaf forest, two deciduous broadleaf forests, three grasslands, and two crop fields spread over Europe and North America. We improved SiB4 in several ways to improve its representation of COS. To account for the effect of atmospheric COS mole fractions on COS biosphere uptake, we replaced the fixed atmospheric COS mole fraction boundary condition originally used in SiB4 with spatially and temporally varying COS mole fraction fields. Seasonal amplitudes of COS mole fractions are ∼50–200 ppt at the investigated sites with a minimum mole fraction in the late growing season. Incorporating seasonal variability into the model reduces COS uptake rates in the late growing season, allowing better agreement with observations. We also replaced the empirical soil COS uptake model in SiB4 with a mechanistic model that represents both uptake and production of COS in soils, which improves the match with observations over agricultural fields and fertilized grassland soils. The improved version of SiB4 was capable of simulating the diurnal and seasonal variation in COS fluxes in the boreal, temperate, and Mediterranean region. Nonetheless, the daytime vegetation COS flux is underestimated on average by 8±27 %, albeit with large variability across sites. On a global scale, our model modifications decreased the modeled COS terrestrial biosphere sink from 922 Gg S yr−1 in the original SiB4 to 753 Gg S yr−1 in the updated version. The largest decrease in fluxes was driven by lower atmospheric COS mole fractions over regions with high productivity, which highlights the importance of accounting for variations in atmospheric COS mole fractions. The change to a different soil model, on the other hand, had a relatively small effect on the global biosphere COS sink. The secondary role of the modeled soil component in the global COS budget supports the use of COS as a global photosynthesis tracer. A more accurate representation of COS uptake in SiB4 should allow for improved application of atmospheric COS as a tracer of local- to global-scale terrestrial photosynthesis.

scholarly journals Inverse modelling of carbonyl sulfide: implementation, evaluation and implications for the global budget

2021 ◽  
Vol 21 (5) ◽  
pp. 3507-3529
Author(s):  
Jin Ma ◽  
Linda M. J. Kooijmans ◽  
Ara Cho ◽  
Stephen A. Montzka ◽  
Norbert Glatthor ◽  
...  
Keyword(s):  
Mole Fraction ◽  
Satellite Data ◽  
Dimethyl Sulfide ◽  
Transport Model ◽  
Carbonyl Sulfide ◽  
Stratospheric Aerosol ◽  
Inverse Modelling ◽  
Model Framework ◽  
Tropical Ocean ◽  
Biosphere Model

Abstract. Carbonyl sulfide (COS) has the potential to be used as a climate diagnostic due to its close coupling to the biospheric uptake of CO2 and its role in the formation of stratospheric aerosol. The current understanding of the COS budget, however, lacks COS sources, which have previously been allocated to the tropical ocean. This paper presents a first attempt at global inverse modelling of COS within the 4-dimensional variational data-assimilation system of the TM5 chemistry transport model (TM5-4DVAR) and a comparison of the results with various COS observations. We focus on the global COS budget, including COS production from its precursors carbon disulfide (CS2) and dimethyl sulfide (DMS). To this end, we implemented COS uptake by soil and vegetation from an updated biosphere model (Simple Biosphere Model – SiB4). In the calculation of these fluxes, a fixed atmospheric mole fraction of 500 pmol mol−1 was assumed. We also used new inventories for anthropogenic and biomass burning emissions. The model framework is capable of closing the COS budget by optimizing for missing emissions using NOAA observations in the period 2000–2012. The addition of 432 Gg a−1 (as S equivalents) of COS is required to obtain a good fit with NOAA observations. This missing source shows few year-to-year variations but considerable seasonal variations. We found that the missing sources are likely located in the tropical regions, and an overestimated biospheric sink in the tropics cannot be ruled out due to missing observations in the tropical continental boundary layer. Moreover, high latitudes in the Northern Hemisphere require extra COS uptake or reduced emissions. HIPPO (HIAPER Pole-to-Pole Observations) aircraft observations, NOAA airborne profiles from an ongoing monitoring programme and several satellite data sources are used to evaluate the optimized model results. This evaluation indicates that COS mole fractions in the free troposphere remain underestimated after optimization. Assimilation of HIPPO observations slightly improves this model bias, which implies that additional observations are urgently required to constrain sources and sinks of COS. We finally find that the biosphere flux dependency on the surface COS mole fraction (which was not accounted for in this study) may substantially lower the fluxes of the SiB4 biosphere model over strong-uptake regions. Using COS mole fractions from our inversion, the prior biosphere flux reduces from 1053 to 851 Gg a−1, which is closer to 738 Gg a−1 as was found by Berry et al. (2013). In planned further studies we will implement this biosphere dependency and additionally assimilate satellite data with the aim of better separating the role of the oceans and the biosphere in the global COS budget.

scholarly journals Towards understanding the variability in biospheric CO<sub>2</sub> fluxes: using FTIR spectrometry and a chemical transport model to investigate the sources and sinks of carbonyl sulfide and its link to CO<sub>2</sub>

2016 ◽  
Vol 16 (4) ◽  
pp. 2123-2138 ◽  
Author(s):  
Yuting Wang ◽  
Nicholas M. Deutscher ◽  
Mathias Palm ◽  
Thorsten Warneke ◽  
Justus Notholt ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Transport Model ◽  
Carbonyl Sulfide ◽  
Co2 Concentration ◽  
Chemical Transport ◽  
Chemical Transport Model ◽  
Solar Absorption ◽  
Ftir Spectrometry ◽  
Carbon Dioxide Co2 ◽  
Biosphere Model

Abstract. Understanding carbon dioxide (CO2) biospheric processes is of great importance because the terrestrial exchange drives the seasonal and interannual variability of CO2 in the atmosphere. Atmospheric inversions based on CO2 concentration measurements alone can only determine net biosphere fluxes, but not differentiate between photosynthesis (uptake) and respiration (production). Carbonyl sulfide (OCS) could provide an important additional constraint: it is also taken up by plants during photosynthesis but not emitted during respiration, and therefore is a potential means to differentiate between these processes. Solar absorption Fourier Transform InfraRed (FTIR) spectrometry allows for the retrievals of the atmospheric concentrations of both CO2 and OCS from measured solar absorption spectra. Here, we investigate co-located and quasi-simultaneous FTIR measurements of OCS and CO2 performed at five selected sites located in the Northern Hemisphere. These measurements are compared to simulations of OCS and CO2 using a chemical transport model (GEOS-Chem). The coupled biospheric fluxes of OCS and CO2 from the simple biosphere model (SiB) are used in the study. The CO2 simulation with SiB fluxes agrees with the measurements well, while the OCS simulation reproduced a weaker drawdown than FTIR measurements at selected sites, and a smaller latitudinal gradient in the Northern Hemisphere during growing season when comparing with HIPPO (HIAPER Pole-to-Pole Observations) data spanning both hemispheres. An offset in the timing of the seasonal cycle minimum between SiB simulation and measurements is also seen. Using OCS as a photosynthesis proxy can help to understand how the biospheric processes are reproduced in models and to further understand the carbon cycle in the real world.

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