scholarly journals Assessment of model estimates of land–atmosphere CO<sub>2</sub> exchange across Northern Eurasia

2015 ◽  
Vol 12 (3) ◽  
pp. 2257-2305 ◽  
Author(s):  
M. A. Rawlins ◽  
A. D. McGuire ◽  
J. K. Kimball ◽  
P. Dass ◽  
D. Lawrence ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Soil Respiration ◽  
Soil Carbon ◽  
Residence Time ◽  
Primary Productivity ◽  
Ecosystem Respiration ◽  
Co2 Exchange ◽  
Northern Eurasia ◽  
Vegetation Productivity ◽  
Model Simulations

Abstract. A warming climate is altering land–atmosphere exchanges of carbon, with a potential for increased vegetation productivity as well as the mobilization of permafrost soil carbon stores. Here we investigate land–atmosphere carbon dioxide (CO2) dynamics through analysis of net ecosystem productivity (NEP) and its component fluxes of gross primary productivity (GPP) and ecosystem respiration (ER) and soil carbon residence time, simulated by a set of land surface models (LSMs) over a region spanning the drainage basin of northern Eurasia. The retrospective simulations were conducted over the 1960–2009 record and at 0.5° resolution, which is a scale common among many global carbon and climate model simulations. Model performance benchmarks were drawn from comparisons against both observed CO2 fluxes derived from site-based eddy covariance measurements as well as regional-scale GPP estimates based on satellite remote sensing data. The site-based comparisons show the timing of peak GPP to be well simulated. Modest overestimates in model GPP and ER are also found, which are relatively higher for two boreal forest validation sites than the two tundra sites. Across the suite of model simulations, NEP increases by as little as 0.01 to as much as 0.79 g C m−2 yr−2, equivalent to 3 to 340% of the respective model means, over the analysis period. For the multimodel average the increase is 135% of the mean from the first to last ten years of record (1960–1969 vs 2000–2009), with a weakening CO2 sink over the latter decades. Vegetation net primary productivity increased by 8 to 30% from the first to last ten years, contributing to soil carbon storage gains, while model mean residence time for soil organic carbon decreased by 10% (−5 to −16%). This suggests that inputs to the soil carbon pool exceeded losses, resulting in a net gain amid a decrease in residence time. Our analysis points to improvements in model elements controlling vegetation productivity and soil respiration as being needed for reducing uncertainty in land–atmosphere CO2 exchange. These advances require collection of new field data on vegetation and soil dynamics, the development of benchmarking datasets from measurements and remote sensing observations, and investments in future model development and intercomparison studies. Resulting improvements in parameterizations and processes driving productivity and soil respiration rates will increase confidence in model estimates of net CO2 exchange, component carbon fluxes, and underlying drivers of change across the northern high latitudes.

scholarly journals Assessment of model estimates of land-atmosphere CO<sub>2</sub> exchange across Northern Eurasia

2015 ◽  
Vol 12 (14) ◽  
pp. 4385-4405 ◽  
Author(s):  
M. A. Rawlins ◽  
A. D. McGuire ◽  
J. S. Kimball ◽  
P. Dass ◽  
D. Lawrence ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Soil Carbon ◽  
Residence Time ◽  
Primary Productivity ◽  
Ecosystem Respiration ◽  
Regional Scale ◽  
Northern Eurasia ◽  
Sink Strength ◽  
Vegetation Productivity ◽  
Co2 Sink

Abstract. A warming climate is altering land-atmosphere exchanges of carbon, with a potential for increased vegetation productivity as well as the mobilization of permafrost soil carbon stores. Here we investigate land-atmosphere carbon dioxide (CO2) cycling through analysis of net ecosystem productivity (NEP) and its component fluxes of gross primary productivity (GPP) and ecosystem respiration (ER) and soil carbon residence time, simulated by a set of land surface models (LSMs) over a region spanning the drainage basin of Northern Eurasia. The retrospective simulations cover the period 1960–2009 at 0.5° resolution, which is a scale common among many global carbon and climate model simulations. Model performance benchmarks were drawn from comparisons against both observed CO2 fluxes derived from site-based eddy covariance measurements as well as regional-scale GPP estimates based on satellite remote-sensing data. The site-based comparisons depict a tendency for overestimates in GPP and ER for several of the models, particularly at the two sites to the south. For several models the spatial pattern in GPP explains less than half the variance in the MODIS MOD17 GPP product. Across the models NEP increases by as little as 0.01 to as much as 0.79 g C m−2 yr−2, equivalent to 3 to 340 % of the respective model means, over the analysis period. For the multimodel average the increase is 135 % of the mean from the first to last 10 years of record (1960–1969 vs. 2000–2009), with a weakening CO2 sink over the latter decades. Vegetation net primary productivity increased by 8 to 30 % from the first to last 10 years, contributing to soil carbon storage gains. The range in regional mean NEP among the group is twice the multimodel mean, indicative of the uncertainty in CO2 sink strength. The models simulate that inputs to the soil carbon pool exceeded losses, resulting in a net soil carbon gain amid a decrease in residence time. Our analysis points to improvements in model elements controlling vegetation productivity and soil respiration as being needed for reducing uncertainty in land-atmosphere CO2 exchange. These advances will require collection of new field data on vegetation and soil dynamics, the development of benchmarking data sets from measurements and remote-sensing observations, and investments in future model development and intercomparison studies.

scholarly journals Partitioning of canopy and soil CO<sub>2</sub> fluxes in a pine forest at the dry timberline across a 13-year observation period

2020 ◽  
Vol 17 (3) ◽  
pp. 699-714
Author(s):  
Rafat Qubaja ◽  
Fyodor Tatarinov ◽  
Eyal Rotenberg ◽  
Dan Yakir
Keyword(s):  
Soil Respiration ◽  
Primary Productivity ◽  
Pinus Halepensis ◽  
Ecosystem Respiration ◽  
Carbon Accumulation ◽  
Dry Forest ◽  
Mean Annual Precipitation ◽  
Co2 Uptake ◽  
Belowground Carbon Allocation ◽  
Observation Period

Abstract. Partitioning carbon fluxes is key to understanding the process underlying ecosystem response to change. This study used soil and canopy fluxes with stable isotopes (13C) and radiocarbon (14C) measurements in an 18 km2, 50-year-old, dry (287 mm mean annual precipitation; nonirrigated) Pinus halepensis forest plantation in Israel to partition the net ecosystem's CO2 flux into gross primary productivity (GPP) and ecosystem respiration (Re) and (with the aid of isotopic measurements) soil respiration flux (Rs) into autotrophic (Rsa), heterotrophic (Rh), and inorganic (Ri) components. On an annual scale, GPP and Re were 655 and 488 g C m−2, respectively, with a net primary productivity (NPP) of 282 g C m−2 and carbon-use efficiency (CUE = NPP ∕ GPP) of 0.43. Rs made up 60 % of the Re and comprised 24±4 %Rsa, 23±4 %Rh, and 13±1 %Ri. The contribution of root and microbial respiration to Re increased during high productivity periods, and inorganic sources were more significant components when the soil water content was low. Comparing the ratio of the respiration components to Re of our mean 2016 values to those of 2003 (mean for 2001–2006) at the same site indicated a decrease in the autotrophic components (roots, foliage, and wood) by about −13 % and an increase in the heterotrophic component (Rh∕Re) by about +18 %, with similar trends for soil respiration (Rsa∕Rs decreasing by −19 % and Rh∕Rs increasing by +8 %, respectively). The soil respiration sensitivity to temperature (Q10) decreased across the same observation period by 36 % and 9 % in the wet and dry periods, respectively. Low rates of soil carbon loss combined with relatively high belowground carbon allocation (i.e., 38 % of canopy CO2 uptake) and low sensitivity to temperature help explain the high soil organic carbon accumulation and the relatively high ecosystem CUE of the dry forest.

scholarly journals Partitioning of canopy and soil CO<sub>2</sub> fluxes in a pine forests at the dry timberline

2019 ◽  
Author(s):  
Rafat Qubaja ◽  
Feyodor Tatarinov ◽  
Eyal Rotenberg ◽  
Dan Yakir
Keyword(s):  
Soil Respiration ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Carbon Allocation ◽  
Ecosystem Respiration ◽  
Pine Forest ◽  
Carbon Accumulation ◽  
Dry Forest ◽  
Co2 Uptake ◽  
The Mean

Abstract. Partitioning carbon fluxes is key to understanding the process underlying ecosystem response to change. This study used soil and canopy fluxes with stable isotopes (13C) and radiocarbon (14C) measurements of a 50-year-old dry (i.e., 287 mm of annual precipitation) pine forest to partition the ecosystem’s CO2 flux into gross primary productivity (GPP) and ecosystem respiration (Re) and soil respiration flux into autotrophic (Rsa), heterotrophic (Rh), and inorganic (Ri) components. On an annual scale, GPP and Re were 655 and 488 g C m−2, respectively, with a net primary productivity (NPP) of 276 g C m−2 and carbon-use efficiency (CUE = NPP / GPP) of 0.42. Soil respiration (Rs) made up 60 % of the total ecosystem respiration and was comprised of 24 ± 4 %, 23 ± 4 %, and 13 ± 1 % Rsa, Rh, and Ri, respectively. The contribution of root and microbial respiration to Re increased during high productivity periods, and inorganic sources were more significant components when soil water content was low. Compared to the mean values for 2001–2006 at the same site; (Grünzweig et al., 2009), annual Rs decreased by 27 % to the mean 2016 rates of 0.8 ± 0.1 µmol m−2 s−1). This was associated with decrease in the respiration Q10 values across the same observation by 36 % and 9 % in the wet and dry periods, respectively. Low rates of soil carbon loss combined with relatively high below ground carbon allocation (i.e., 40 % of canopy CO2 uptake) help explain the high soil organic carbon accumulation and the relatively high ecosystem CUE of the dry forest. This was indicative of the higher resilience of the pine forest to climate change and the significant potential for carbon sequestration in these regions.

scholarly journals A satellite data driven biophysical modeling approach for estimating northern peatland and tundra CO<sub>2</sub> and CH<sub>4</sub> fluxes

2013 ◽  
Vol 10 (10) ◽  
pp. 16491-16549
Author(s):  
J. D. Watts ◽  
J. S. Kimball ◽  
F.-J. W. Parmentier ◽  
T. Sachs ◽  
J. Rinne ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Ecosystem Respiration ◽  
Co2 Exchange ◽  
Biophysical Modeling ◽  
Climate Data ◽  
Ch4 Emissions ◽  
In Situ Data ◽  
Sensing Applications ◽  
Carbon Dioxide Co2

Abstract. The northern terrestrial net ecosystem carbon balance (NECB) is contingent on inputs from vegetation gross primary productivity (GPP) to offset ecosystem respiration (Reco) of carbon dioxide (CO2) and methane (CH4) emissions, but an effective framework to monitor the regional Arctic NECB is lacking. We modified a terrestrial carbon flux (TCF) model developed for satellite remote sensing applications to estimate peatland and tundra CO2 and CH4 fluxes over a pan-Arctic network of eddy covariance (EC) flux tower sites. The TCF model estimates GPP, CO2 and CH4 emissions using either in-situ or remote sensing based climate data as input. TCF simulations driven using in-situ data explained >70% of the r2 variability in 8 day cumulative EC measured fluxes. Model simulations using coarser satellite (MODIS) and reanalysis (MERRA) data as inputs also reproduced the variability in the EC measured fluxes relatively well for GPP (r2 = 0.75), Reco (r2 = 0.71), net ecosystem CO2 exchange (NEE, r2 = 0.62) and CH4 emissions (r2 = 0.75). Although the estimated annual CH4 emissions were small (<18 g C m−2 yr−1) relative to Reco (>180 g C m−2 yr−1), they reduced the across-site NECB by 23% and contributed to a global warming potential of approximately 165 ± 128 g CO2eq m−2 yr−1 when considered over a 100 yr time span. This model evaluation indicates a strong potential for using the TCF model approach to document landscape scale variability in CO2 and CH4 fluxes, and to estimate the NECB for northern peatland and tundra ecosystems.

scholarly journals A satellite data driven biophysical modeling approach for estimating northern peatland and tundra CO<sub>2</sub> and CH<sub>4</sub> fluxes

2014 ◽  
Vol 11 (7) ◽  
pp. 1961-1980 ◽  
Author(s):  
J. D. Watts ◽  
J. S. Kimball ◽  
F. J. W. Parmentier ◽  
T. Sachs ◽  
J. Rinne ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Ecosystem Respiration ◽  
Biophysical Modeling ◽  
Climate Data ◽  
Model Simulations ◽  
Ch4 Emissions ◽  
In Situ Data ◽  
Sensing Applications ◽  
Carbon Dioxide Co2

Abstract. The northern terrestrial net ecosystem carbon balance (NECB) is contingent on inputs from vegetation gross primary productivity (GPP) to offset the ecosystem respiration (Reco) of carbon dioxide (CO2) and methane (CH4) emissions, but an effective framework to monitor the regional Arctic NECB is lacking. We modified a terrestrial carbon flux (TCF) model developed for satellite remote sensing applications to evaluate wetland CO2 and CH4 fluxes over pan-Arctic eddy covariance (EC) flux tower sites. The TCF model estimates GPP, CO2 and CH4 emissions using in situ or remote sensing and reanalysis-based climate data as inputs. The TCF model simulations using in situ data explained > 70% of the r2 variability in the 8 day cumulative EC measured fluxes. Model simulations using coarser satellite (MODIS) and reanalysis (MERRA) records accounted for approximately 69% and 75% of the respective r2 variability in the tower CO2 and CH4 records, with corresponding RMSE uncertainties of &amp;leq; 1.3 g C m−2 d−1 (CO2) and 18.2 mg C m−2 d−1 (CH4). Although the estimated annual CH4 emissions were small (< 18 g C m−2 yr−1) relative to Reco (> 180 g C m−2 yr−1), they reduced the across-site NECB by 23% and contributed to a global warming potential of approximately 165 ± 128 g CO2eq m−2 yr−1 when considered over a 100 year time span. This model evaluation indicates a strong potential for using the TCF model approach to document landscape-scale variability in CO2 and CH4 fluxes, and to estimate the NECB for northern peatland and tundra ecosystems.

scholarly journals Assessment of organic matter temporal dynamics in the klyazma basin using remote sensing and qgis trends.earth

2021 ◽  
Vol 34 (02) ◽  
pp. 973-992
Author(s):  
Tatiana A. Trifonova ◽  
Natalia V. Mishchenko ◽  
Pavel S. Shutov
Keyword(s):  
Remote Sensing ◽  
Land Use ◽  
Organic Matter ◽  
River Basin ◽  
Primary Productivity ◽  
Catchment Area ◽  
Ecosystem Respiration ◽  
Plant Production ◽  
Biological Processes ◽  
Catchment Areas

The article addresses the dynamics of biological processes in various landscapes within a holistic natural geosystem—a catchment area. The Klyazma river (the fourth order tributary to the Volga) was selected as the object of study. The natural complex of the Klyazma river basin is a combination of different landscapes, each marked by a diverse composition of geomorphological and soil-vegetation structures. The study is based on remote sensing data and the Trends.Earth Land Degradation Monitoring Project (Land Cover Dataset, European Space Agency 2015, 300 m spatial resolution) implemented using the open-source Quantum GIS 2.18. Four landscape provinces and eight site were identified in the studied catchment area according to the geomorphological structure and the soil and vegetation cover. The ecosystem parameters Gross Primary Productivity, Net Primary Productivity, and Ecosystem Respiration were measured in the identified sites. In different landscapes the biological processes, characterizing the organic matter dynamics in the form of plant production and organic matter accumulation, differ in both rate and intensity, and variously respond to the changes in climate parameters and land use. The river basin, as a holistic ecosystem, showed sufficient stability of the dynamic processes. This suggests that holistic natural ecosystems, such as catchment areas, have internal compensatory mechanisms that maintain the development stability over long period of time, while irrational land use remains the main damaging factor.

scholarly journals Increased Litter Greatly Enhancing Soil Respiration in Betula platyphylla Forests of Permafrost Region, Northeast China

Forests ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 89
Author(s):  
Hong Wei ◽  
Xiuling Man
Keyword(s):  
Soil Respiration ◽  
Carbon Cycle ◽  
Soil Carbon ◽  
Northeast China ◽  
Stand Age ◽  
Permafrost Region ◽  
Betula Platyphylla ◽  
Litter Input ◽  
Litter Manipulation ◽  
And Control

The change of litter input can affect soil respiration (Rs) by influencing the availability of soil organic carbon and nutrients, regulating soil microenvironments, thus resulting in a profound influence on soil carbon cycle of the forest ecosystem. We conducted an aboveground litterfall manipulation experiment in different-aged Betula platyphylla forests (25-, 40- and 61-year-old) of the permafrost region, located in the northeast of China, during May to October in 2018, with each stand treated with doubling litter (litter addition, DL), litter exclusion (no-litter, NL) and control litter (CK). Our results indicated that Rs decreased under NL treatment compared with CK treatment. The effect size lessened with the increase in the stand age; the greatest reduction was found for young Betula platyphylla forest (24.46% for 25-year-old stand) and tended to stabilize with the growth of forest with the reduction of 15.65% and 15.23% for 40-and 61- year-old stands, respectively. Meanwhile, under DL treatment, Rs increased by 27.38%, 23.83% and 23.58% on 25-, 40- and 61-year-old stands, respectively. Our results also showed that the increase caused by DL treatment was larger than the reduction caused by NL treatment, leading to a priming effect, especially on 40- and 61-year-old stands. The change in litter input was the principal factor affecting the change of Rs under litter manipulation. The soil temperature was also a main factor affecting the contribution rate of litter to Rs of different-aged stands, which had a significant positive exponential correlation with Rs. This suggests that there is a significant relationship between litter and Rs, which consequently influences the soil carbon cycle in Betula platyphylla forests of the permafrost region, Northeast China. Our finding indicated the increased litter enhanced the Rs in Betula platyphylla forest, which may consequently increase the carbon emission in a warming climate in the future. It is of great importance for future forest management in the permafrost region, Northeast China.

scholarly journals Gross primary productivity of Brazilian Savanna (Cerrado) estimated by different remote sensing-based models

2021 ◽  
Vol 307 ◽  
pp. 108456
Author(s):  
Marcelo Sacardi Biudes ◽  
George Louis Vourlitis ◽  
Maísa Caldas Souza Velasque ◽  
Nadja Gomes Machado ◽  
Victor Hugo de Morais Danelichen ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Primary Productivity ◽  
Gross Primary Productivity ◽  
Brazilian Savanna

scholarly journals Dynamics of the soil respiration response to soil reclamation in a coastal wetland

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiliang Song ◽  
Yihao Zhu ◽  
Weifeng Chen
Keyword(s):  
Soil Respiration ◽  
Soil Temperature ◽  
Soil Carbon ◽  
Water Content ◽  
Coastal Wetlands ◽  
Positive Relationship ◽  
Soil Reclamation ◽  
Diurnal Changes ◽  
Seasonal Scale ◽  
Study Sites

AbstractThe soil carbon (C) pools in coastal wetlands are known as “blue C” and have been damaged extensively owing to climate change and land reclamation. Because soil respiration (RS) is the primary mechanism through which soil carbon is released into the atmosphere at a global scale, investigating the dynamic characteristics of the soil respiration rate in reclaimed coastal wetlands is necessary to understand its important role in maintaining the global C cycle. In the present study, seasonal and diurnal changes in soil respiration were monitored in one bare wetland (CK) and two reclaimed wetlands (CT, a cotton monoculture pattern, and WM, a wheat–maize continuous cropping pattern) in the Yellow River Delta. At the diurnal scale, the RS at the three study sites displayed single-peak curves, with the lowest values occurring at midnight (00:00 a.m.) and the highest values occurring at midday (12:00 a.m.). At the seasonal scale, the mean diurnal RS of the CK, CT and WM in April was 0.24, 0.26 and 0.79 μmol CO2 m−2 s−1, and it increased to a peak in August for these areas. Bare wetland conversion to croplands significantly elevated the soil organic carbon (SOC) pool. The magnitude of the RS was significantly different at the three sites, and the yearly total amounts of CO2 efflux were 375, 513 and 944 g CO2·m−2 for the CK, CT and WM, respectively. At the three study sites, the surface soil temperature had a significant and positive relationship to the RS at both the diurnal and seasonal scales, and it accounted for 20–52% of the seasonal variation in the daytime RS. The soil water content showed a significant but negative relationship to the RS on diurnal scale only at the CK site, while it significantly increased with the RS on seasonal scale at all study sites. Although the RS showed a noticeable relationship to the combination of soil temperature and water content, the synergic effects of these two environment factors were not much higher than the individual effects. In addition, the correlation analysis showed that the RS was also influenced by the soil physico-chemical properties and that the soil total nitrogen had a closer positive relationship to the RS than the other nutrients, indicating that the soil nitrogen content plays a more important role in promoting carbon loss.

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