Pub Date : 1999-04-01DOI: 10.1034/J.1600-0889.1999.00024.X
I. Skjelvan, T. Johannessen, L. Miller
The fCO 2 in the Greenland and Norwegian Seas surface water varied significantly during the period from 1995 to 1997. Comparison of fCO 2 data from winter 1995 with data from winter 1997 showed that sea surface fCO 2 decreased between these winters by 20 to 30 μatm in the central Greenland Sea, and the potential CO 2 uptake during the winters of 1995 and 1997 was 3.9. 10 -3 Gt C month 1 and 5.9.10 -3 Gt C month -1 (based on Wanninkhof's relationship for the gas transfer coeflicient), respectively. This difference in CO 2 fluxes can be attributed to lower sea surface temperatures and more extensive sea ice cover in 1997, and these observations were related to increased convection in the Greenland Sea during winter 1997. Larger amplitudes in the seasonal variations of CO 2 flux were also seen during the other seasons in the period 1996-97. compared to 1995. Over the years of investigation in the Greenland Sea, the carbon flux showed an inereasing trend of 9.10 -4 Gt C yr 1 into the ocean, which may be related to the anthropogenic input of carbor, to the atmosphere. The Greenland and Norwegian Seas appear to be sinks for atmospheric CO 2 and together absorb approximately 0.12±0.015 Gt C yr -1 .
{"title":"Interannual variability of fCO2 in the Greenland and Norwegian Seas","authors":"I. Skjelvan, T. Johannessen, L. Miller","doi":"10.1034/J.1600-0889.1999.00024.X","DOIUrl":"https://doi.org/10.1034/J.1600-0889.1999.00024.X","url":null,"abstract":"The fCO 2 in the Greenland and Norwegian Seas surface water varied significantly during the period from 1995 to 1997. Comparison of fCO 2 data from winter 1995 with data from winter 1997 showed that sea surface fCO 2 decreased between these winters by 20 to 30 μatm in the central Greenland Sea, and the potential CO 2 uptake during the winters of 1995 and 1997 was 3.9. 10 -3 Gt C month 1 and 5.9.10 -3 Gt C month -1 (based on Wanninkhof's relationship for the gas transfer coeflicient), respectively. This difference in CO 2 fluxes can be attributed to lower sea surface temperatures and more extensive sea ice cover in 1997, and these observations were related to increased convection in the Greenland Sea during winter 1997. Larger amplitudes in the seasonal variations of CO 2 flux were also seen during the other seasons in the period 1996-97. compared to 1995. Over the years of investigation in the Greenland Sea, the carbon flux showed an inereasing trend of 9.10 -4 Gt C yr 1 into the ocean, which may be related to the anthropogenic input of carbor, to the atmosphere. The Greenland and Norwegian Seas appear to be sinks for atmospheric CO 2 and together absorb approximately 0.12±0.015 Gt C yr -1 .","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":"33 1","pages":"477-489"},"PeriodicalIF":2.3,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79741851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-04-01DOI: 10.3402/TELLUSB.V51I2.16332
J. Boutin, J. Etcheto, Y. Dandonneau, D. Bakker, R. Feely, H. Inoue, M. Ishii, R. Ling, P. Nightingale, N. Metzl, R. Wanninkhof
In order to determine the seasonal and interannual variability of the CO 2 released to the atmosphere from the equatorial Pacific, we have developed p CO 2 -temperature relationships based upon shipboard oceanic CO 2 partial pressure measurements, p CO 2 , and satellite sea surface temperature, SST, measurements. We interpret the spatial variability in p CO 2 with the help of the SST imagery. In the eastern equatorial Pacific, at 5°S, p CO 2 variations of up to 100 μatm are caused by undulations in the southern boundary of the equatorial upwelled waters. These undulations appear to be periodic with a phase and a wavelength comparable to tropical instability waves, TIW, observed at the northern boundary of the equatorial upwelling. Once the p CO 2 signature of the TIW is removed from the Alize II cruise measurements in January 1991, the equatorial p CO 2 data exhibit a diel cycle of about 10 matm with maximum values occurring at night. In the western equatorial Pacific, the variability in p CO 2 is primarily governed by the displacement of the boundary between warm pool waters, where air–sea CO 2 fluxes are weak, and equatorial upwelled waters which release high CO 2 fluxes to the atmosphere. We detect this boundary using satellite SST maps. East of the warm pool, Δ P is related to SST and SST anomalies. The 1985–97 CO 2 flux is computed in a 5° wide latitudinal band as a combination of Δ P and CO 2 exchange coefficient, K , deduced from satellite wind speeds, U . It exhibits up to a factor 2 seasonal variation caused by K -seasonal variation and a large interannual variability, a factor 5 variation between 1987 and 1988. The interannual variability is primarily driven by displacements of the warm pool that makes the surface area of the outgassing region variable. The contribution of Δ P to the flux variability is about half the contribution of K . The mean CO 2 flux computed using either the Liss and Merlivat (1986) or the Wanninkhof (1992) K – U parametrization amounts to 0.11 GtC yr −1 or to 0.18 GtC yr −1 , respectively. The error in the integrated flux, without taking into account the uncertainty on the K – U parametrization, is less than 31%. DOI: 10.1034/j.1600-0889.1999.00025.x
{"title":"Satellite sea surface temperature: a powerful tool for interpreting in situ pCO2 measurements in the equatorial Pacific Ocean","authors":"J. Boutin, J. Etcheto, Y. Dandonneau, D. Bakker, R. Feely, H. Inoue, M. Ishii, R. Ling, P. Nightingale, N. Metzl, R. Wanninkhof","doi":"10.3402/TELLUSB.V51I2.16332","DOIUrl":"https://doi.org/10.3402/TELLUSB.V51I2.16332","url":null,"abstract":"In order to determine the seasonal and interannual variability of the CO 2 released to the atmosphere from the equatorial Pacific, we have developed p CO 2 -temperature relationships based upon shipboard oceanic CO 2 partial pressure measurements, p CO 2 , and satellite sea surface temperature, SST, measurements. We interpret the spatial variability in p CO 2 with the help of the SST imagery. In the eastern equatorial Pacific, at 5°S, p CO 2 variations of up to 100 μatm are caused by undulations in the southern boundary of the equatorial upwelled waters. These undulations appear to be periodic with a phase and a wavelength comparable to tropical instability waves, TIW, observed at the northern boundary of the equatorial upwelling. Once the p CO 2 signature of the TIW is removed from the Alize II cruise measurements in January 1991, the equatorial p CO 2 data exhibit a diel cycle of about 10 matm with maximum values occurring at night. In the western equatorial Pacific, the variability in p CO 2 is primarily governed by the displacement of the boundary between warm pool waters, where air–sea CO 2 fluxes are weak, and equatorial upwelled waters which release high CO 2 fluxes to the atmosphere. We detect this boundary using satellite SST maps. East of the warm pool, Δ P is related to SST and SST anomalies. The 1985–97 CO 2 flux is computed in a 5° wide latitudinal band as a combination of Δ P and CO 2 exchange coefficient, K , deduced from satellite wind speeds, U . It exhibits up to a factor 2 seasonal variation caused by K -seasonal variation and a large interannual variability, a factor 5 variation between 1987 and 1988. The interannual variability is primarily driven by displacements of the warm pool that makes the surface area of the outgassing region variable. The contribution of Δ P to the flux variability is about half the contribution of K . The mean CO 2 flux computed using either the Liss and Merlivat (1986) or the Wanninkhof (1992) K – U parametrization amounts to 0.11 GtC yr −1 or to 0.18 GtC yr −1 , respectively. The error in the integrated flux, without taking into account the uncertainty on the K – U parametrization, is less than 31%. DOI: 10.1034/j.1600-0889.1999.00025.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":"9 1","pages":"490-508"},"PeriodicalIF":2.3,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82066277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-04-01DOI: 10.1034/J.1600-0889.1999.00016.X
J. Lloyd
Over the last 5 or so years, there have been significant advances in the understanding of the current role of the terrestrial biosphere in the global carbon cycle, especially in terms of how pools and fluxes are affected by variations in climate (including interannual variability as well as longer-term climate change), increases in atmospheric CO 2 concentrations and changed rates of atmospheric nitrogen deposition. At the same time, significant advances have been made in terms of both direct measurement of ecosystem productivity and in an understanding of the key underlying mechanisms modulating carbon fluxes from terrestrial systems. A brief synopsis of these advances is the subject of this paper. DOI: 10.1034/j.1600-0889.1999.00016.x
{"title":"Current perspectives on the terrestrial carbon cycle","authors":"J. Lloyd","doi":"10.1034/J.1600-0889.1999.00016.X","DOIUrl":"https://doi.org/10.1034/J.1600-0889.1999.00016.X","url":null,"abstract":"Over the last 5 or so years, there have been significant advances in the understanding of the current role of the terrestrial biosphere in the global carbon cycle, especially in terms of how pools and fluxes are affected by variations in climate (including interannual variability as well as longer-term climate change), increases in atmospheric CO 2 concentrations and changed rates of atmospheric nitrogen deposition. At the same time, significant advances have been made in terms of both direct measurement of ecosystem productivity and in an understanding of the key underlying mechanisms modulating carbon fluxes from terrestrial systems. A brief synopsis of these advances is the subject of this paper. DOI: 10.1034/j.1600-0889.1999.00016.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":"19 1","pages":"336-342"},"PeriodicalIF":2.3,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76191252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-04-01DOI: 10.3402/TELLUSB.V51I2.16281
R. Law
Carbon dioxide sources for 1981–1995 are calculated using a mass-balance inversion method. Options for deriving a suitable surface constraint for the model from the available observed data are assessed. A new method, in which the longitudinal variation in the observations is accounted for, is compared to a more conventional spline fit to the data. This new constraint is applied either to the zonal mean concentration or to the concentration at all grid points. The results indicate relatively large differences between long-term mean regional sources but relatively good agreement of the interannual variations. The global and tropical sources estimated show a surprising relationship to the southern oscillation index; maximum correlation occurs for CO 2 sources leading the SOI by around 9 months. DOI: 10.1034/j.1600-0889.1999.00011.x
{"title":"CO2 sources from a mass-balance inversion: sensitivity to the surface constraint","authors":"R. Law","doi":"10.3402/TELLUSB.V51I2.16281","DOIUrl":"https://doi.org/10.3402/TELLUSB.V51I2.16281","url":null,"abstract":"Carbon dioxide sources for 1981–1995 are calculated using a mass-balance inversion method. Options for deriving a suitable surface constraint for the model from the available observed data are assessed. A new method, in which the longitudinal variation in the observations is accounted for, is compared to a more conventional spline fit to the data. This new constraint is applied either to the zonal mean concentration or to the concentration at all grid points. The results indicate relatively large differences between long-term mean regional sources but relatively good agreement of the interannual variations. The global and tropical sources estimated show a surprising relationship to the southern oscillation index; maximum correlation occurs for CO 2 sources leading the SOI by around 9 months. DOI: 10.1034/j.1600-0889.1999.00011.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":"54 1","pages":"254-265"},"PeriodicalIF":2.3,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77624919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-04-01DOI: 10.1034/J.1600-0889.1999.00017.X
D. Kicklighter, M. Bruno, S. Dönges, G. Esser, M. Heimann, John V. K. Helfrich, F. Ift, F. Joos, J. Kaduk, G. Kohlmaier, A. McGuire, J. Melillo, R. Meyer, B. Moore, A. Nadler, I. Prentice, W. Sauf, A. Schloss, S. Sitch, U. Wittenberg, G. Würth
We compared the simulated responses of net primary production, heterotrophic respiration, net ecosystem production and carbon storage in natural terrestrial ecosystems to historical (1765 to 1990) and projected (1990–2300) changes of atmospheric CO 2 concentration of four terrestrial biosphere models: the Bern model, the Frankfurt Biosphere Model (FBM), the High-Resolution Biosphere Model (HRBM) and the Terrestrial EcosystemModel (TEM). The results of the model intercomparison suggest that CO 2 fertilization of natural terrestrial vegetation has the potential to account for a large fraction of the so-called ‘‘missing carbon sink’′ of 2.0 Pg C in 1990. Estimates of this potential are reduced when the models incorporate the concept that CO 2 fertilization can be limited by nutrient availability. Although the model estimates differ on the potential size (126 to 461 Pg C) of the future terrestrial sink caused by CO 2 fertilization, the results of the four models suggest that natural terrestrial ecosystems will have a limited capacity to act as a sink of atmospheric CO 2 in the future as a result of physiological constraints and nutrient constraints on NPP. All the spatially explicit models estimate a carbon sink in both tropical and northern temperate regions, but the strength of these sinks varies over time. Differences in the simulated response of terrestrial ecosystems to CO 2 fertilization among the models in this intercomparison study reflect the fact that the models have highlighted different aspects of the effect of CO 2 fertilization on carbon dynamics of natural terrestrial ecosystems including feedback mechanisms. As interactions with nitrogen fertilization, climate change and forest regrowth may play an important role in simulating the response of terrestrial ecosystems to CO 2 fertilization, these factors should be included in future analyses. Improvements in spatially explicit data sets, whole-ecosystem experiments and the availability of net carbon exchange measurements across the globe will also help to improve future evaluations of the role of CO 2 fertilization on terrestrial carbon storage. DOI: 10.1034/j.1600-0889.1999.00017.x
{"title":"A first‐order analysis of the potential rôle of CO2 fertilization to affect the global carbon budget: a comparison of four terrestrial biosphere models","authors":"D. Kicklighter, M. Bruno, S. Dönges, G. Esser, M. Heimann, John V. K. Helfrich, F. Ift, F. Joos, J. Kaduk, G. Kohlmaier, A. McGuire, J. Melillo, R. Meyer, B. Moore, A. Nadler, I. Prentice, W. Sauf, A. Schloss, S. Sitch, U. Wittenberg, G. Würth","doi":"10.1034/J.1600-0889.1999.00017.X","DOIUrl":"https://doi.org/10.1034/J.1600-0889.1999.00017.X","url":null,"abstract":"We compared the simulated responses of net primary production, heterotrophic respiration, net ecosystem production and carbon storage in natural terrestrial ecosystems to historical (1765 to 1990) and projected (1990–2300) changes of atmospheric CO 2 concentration of four terrestrial biosphere models: the Bern model, the Frankfurt Biosphere Model (FBM), the High-Resolution Biosphere Model (HRBM) and the Terrestrial EcosystemModel (TEM). The results of the model intercomparison suggest that CO 2 fertilization of natural terrestrial vegetation has the potential to account for a large fraction of the so-called ‘‘missing carbon sink’′ of 2.0 Pg C in 1990. Estimates of this potential are reduced when the models incorporate the concept that CO 2 fertilization can be limited by nutrient availability. Although the model estimates differ on the potential size (126 to 461 Pg C) of the future terrestrial sink caused by CO 2 fertilization, the results of the four models suggest that natural terrestrial ecosystems will have a limited capacity to act as a sink of atmospheric CO 2 in the future as a result of physiological constraints and nutrient constraints on NPP. All the spatially explicit models estimate a carbon sink in both tropical and northern temperate regions, but the strength of these sinks varies over time. Differences in the simulated response of terrestrial ecosystems to CO 2 fertilization among the models in this intercomparison study reflect the fact that the models have highlighted different aspects of the effect of CO 2 fertilization on carbon dynamics of natural terrestrial ecosystems including feedback mechanisms. As interactions with nitrogen fertilization, climate change and forest regrowth may play an important role in simulating the response of terrestrial ecosystems to CO 2 fertilization, these factors should be included in future analyses. Improvements in spatially explicit data sets, whole-ecosystem experiments and the availability of net carbon exchange measurements across the globe will also help to improve future evaluations of the role of CO 2 fertilization on terrestrial carbon storage. DOI: 10.1034/j.1600-0889.1999.00017.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":"23 1","pages":"343-366"},"PeriodicalIF":2.3,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76980129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-04-01DOI: 10.3402/TELLUSB.V51I2.16270
M. Engardt, K. Holmén
We describe, and use, a limited area, 3-dimensional transport model. The model domain is located over the Arctic, but includes the majority of the anthropogenic CO 2 emissions in western and eastern Europe, which together make up about 1/3 of the global CO 2 emissions. The model is run for several winter periods, using anthropogenic CO 2 emissions only, and the results are compared with independent CO 2 measurements taken at a monitoring station on Spitsbergen in the high Arctic. We show that the initial concentrations and boundary values of the domain are not crucial for the results, and conclude that most of the measured variability above the winter baseline in CO 2 at the Arctic monitoring station emanates from recent CO 2 sources within the model domain. From the observed small spatial variability in the monthly mean atmospheric CO 2 mixing ratio in the north Atlantic region, we assume that there is only little net exchange between the atmosphere and ocean during the studied periods. Based on the co-variation between CO 2 and particulate mass, we hypothesise that most of the measured CO 2 variability is due to anthropogenic fossil fuel emissions, although we can not rule out a biogenic CO 2 component. Using the transport model, we compare different estimates of fossil-fuel consumption in the mid-latitudes. We find that the industrial centres and the surrounding gas- fields in the lower-Ob region (60°−72°N, 65°−80°E) occasionally have a much larger impact on the CO 2 measurements at Spitsbergen than follows from a recent CO 2 emission inventory. This implies that there may be an overlooked CO 2 source in this region, possibly flaring of gas. DOI: 10.1034/j.1600-0889.1999.t01-1-00006.x
{"title":"Model simulations of anthropogenic-CO2 transport to an Arctic monitoring station during winter","authors":"M. Engardt, K. Holmén","doi":"10.3402/TELLUSB.V51I2.16270","DOIUrl":"https://doi.org/10.3402/TELLUSB.V51I2.16270","url":null,"abstract":"We describe, and use, a limited area, 3-dimensional transport model. The model domain is located over the Arctic, but includes the majority of the anthropogenic CO 2 emissions in western and eastern Europe, which together make up about 1/3 of the global CO 2 emissions. The model is run for several winter periods, using anthropogenic CO 2 emissions only, and the results are compared with independent CO 2 measurements taken at a monitoring station on Spitsbergen in the high Arctic. We show that the initial concentrations and boundary values of the domain are not crucial for the results, and conclude that most of the measured variability above the winter baseline in CO 2 at the Arctic monitoring station emanates from recent CO 2 sources within the model domain. From the observed small spatial variability in the monthly mean atmospheric CO 2 mixing ratio in the north Atlantic region, we assume that there is only little net exchange between the atmosphere and ocean during the studied periods. Based on the co-variation between CO 2 and particulate mass, we hypothesise that most of the measured CO 2 variability is due to anthropogenic fossil fuel emissions, although we can not rule out a biogenic CO 2 component. Using the transport model, we compare different estimates of fossil-fuel consumption in the mid-latitudes. We find that the industrial centres and the surrounding gas- fields in the lower-Ob region (60°−72°N, 65°−80°E) occasionally have a much larger impact on the CO 2 measurements at Spitsbergen than follows from a recent CO 2 emission inventory. This implies that there may be an overlooked CO 2 source in this region, possibly flaring of gas. DOI: 10.1034/j.1600-0889.1999.t01-1-00006.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":"1 1","pages":"194-209"},"PeriodicalIF":2.3,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83552743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-04-01DOI: 10.3402/TELLUSB.V51I2.16267
W. Ludwig, J. Probst
Atmospheric CO 2 is consumed both by organic matter formation and chemical rock weathering, and subsequently discharged as dissolved organic carbon, particulate organic carbon, and dissolved inorganic carbon to the oceans by rivers. In the long term, varying the ratio of the amount of atmospheric CO 2 consumed by continental erosion and the amount of CO 2 released during carbonate precipitation and organic matter respiration in the oceans can change the CO 2 content in the atmosphere. The purpose of this paper is to determine whether riverine organic carbon fluxes during the last glacial maximum (LGM) may have been different from today in order to assess the potential impact on atmospheric CO 2 . Previous studies mainly focused on the role of the river fluxes of inorganic carbon in this respect, but none of them examined possible variations in the fluxes of organic carbon, although the erosion of organic carbon actually represents the bulk of the atmospheric CO 2 consumption by continental erosion. We therefore applied a global carbon erosion model to a LGM scenario in order to determine the riverine fluxes of organic matter during that time. The climatic conditions during the LGM were reconstructed using a computer simulation with a general circulation model. It is found that during the LGM the riverine organic carbon input into the oceans was at least ∼10% lower than today. Most of the reduction of the total organic matter fluxes is due to the reduction of the fluxes of dissolved organic carbon. The fluxes of particulate organic carbon remained almost unchanged. The oceanic response to the lower carbon input was estimated on the basis of a present-day steady state budget for organic river carbon in the oceans, and implies that the reduction of the river fluxes were more than counterbalanced by lower burial rates due to the smaller shelf area during the LGM. This suggests that both the lower river carbon input and the relatively greater share of this carbon being subjected to oceanic respiration, acted as a negative feedback to the low atmospheric CO 2 content during the LGM. DOI: 10.1034/j.1600-0889.1999.t01-1-00003.x
{"title":"Soil erosion and atmospheric CO2 during the last glacial maximum: the rôle of riverine organic matter fluxes","authors":"W. Ludwig, J. Probst","doi":"10.3402/TELLUSB.V51I2.16267","DOIUrl":"https://doi.org/10.3402/TELLUSB.V51I2.16267","url":null,"abstract":"Atmospheric CO 2 is consumed both by organic matter formation and chemical rock weathering, and subsequently discharged as dissolved organic carbon, particulate organic carbon, and dissolved inorganic carbon to the oceans by rivers. In the long term, varying the ratio of the amount of atmospheric CO 2 consumed by continental erosion and the amount of CO 2 released during carbonate precipitation and organic matter respiration in the oceans can change the CO 2 content in the atmosphere. The purpose of this paper is to determine whether riverine organic carbon fluxes during the last glacial maximum (LGM) may have been different from today in order to assess the potential impact on atmospheric CO 2 . Previous studies mainly focused on the role of the river fluxes of inorganic carbon in this respect, but none of them examined possible variations in the fluxes of organic carbon, although the erosion of organic carbon actually represents the bulk of the atmospheric CO 2 consumption by continental erosion. We therefore applied a global carbon erosion model to a LGM scenario in order to determine the riverine fluxes of organic matter during that time. The climatic conditions during the LGM were reconstructed using a computer simulation with a general circulation model. It is found that during the LGM the riverine organic carbon input into the oceans was at least ∼10% lower than today. Most of the reduction of the total organic matter fluxes is due to the reduction of the fluxes of dissolved organic carbon. The fluxes of particulate organic carbon remained almost unchanged. The oceanic response to the lower carbon input was estimated on the basis of a present-day steady state budget for organic river carbon in the oceans, and implies that the reduction of the river fluxes were more than counterbalanced by lower burial rates due to the smaller shelf area during the LGM. This suggests that both the lower river carbon input and the relatively greater share of this carbon being subjected to oceanic respiration, acted as a negative feedback to the low atmospheric CO 2 content during the LGM. DOI: 10.1034/j.1600-0889.1999.t01-1-00003.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":"1 1","pages":"156-164"},"PeriodicalIF":2.3,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90401307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-04-01DOI: 10.3402/TELLUSB.V51I2.16277
A. Denning, Taro Takahashi, P. Friedlingstein
Atmospheric CO 2 accumulates near the Earth's surface because of relatively deeper vertical mixing when photosynthesis is active than when it is not. Some models simulate an excess of more than 2.5 ppmv CO 2 in the remote Northern Hemisphere due to this ‘‘rectification’′ of an annually balanced terrestrial carbon cycle. The covariance between CO 2 flux and vertical mixing, and the resulting vertical structure of CO 2 are generally consistent with field data at local scales, but it is difficult to reconcile such a strong rectifier signal with current ideas about the global carbon budget. A rectifier effect of 2.5 ppmv at northern flask sampling stations implies an unreasonably strong northern sink of atmospheric CO 2 , and a corresponding source in the tropics or Southern Hemisphere. DOI: 10.1034/j.1600-0889.1999.t01-1-00010.x
{"title":"Can a strong atmospheric CO2 rectifier effect be reconciled with a “reasonable” carbon budget?","authors":"A. Denning, Taro Takahashi, P. Friedlingstein","doi":"10.3402/TELLUSB.V51I2.16277","DOIUrl":"https://doi.org/10.3402/TELLUSB.V51I2.16277","url":null,"abstract":"Atmospheric CO 2 accumulates near the Earth's surface because of relatively deeper vertical mixing when photosynthesis is active than when it is not. Some models simulate an excess of more than 2.5 ppmv CO 2 in the remote Northern Hemisphere due to this ‘‘rectification’′ of an annually balanced terrestrial carbon cycle. The covariance between CO 2 flux and vertical mixing, and the resulting vertical structure of CO 2 are generally consistent with field data at local scales, but it is difficult to reconcile such a strong rectifier signal with current ideas about the global carbon budget. A rectifier effect of 2.5 ppmv at northern flask sampling stations implies an unreasonably strong northern sink of atmospheric CO 2 , and a corresponding source in the tropics or Southern Hemisphere. DOI: 10.1034/j.1600-0889.1999.t01-1-00010.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":"735 1","pages":"249-253"},"PeriodicalIF":2.3,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76803018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-04-01DOI: 10.3402/TELLUSB.V51I2.16327
I. Skjelvan, T. Johannessen, L. Miller
The f CO 2 in the Greenland and Norwegian Seas surface water varied significantly during the period from 1995 to 1997. Comparison of f CO 2 data from winter 1995 with data from winter 1997 showed that sea surface f CO 2 decreased between these winters by 20–30 μatm in the central Greenland Sea, and the potential CO 2 uptake during the winters of 1995 and 1997 was 3.9·10 −3 Gt C month −1 and 5.9·10 −3 Gt C month −1 (based on Wanninkhof ′s relationship for the gas transfer coeYcient), respectively. This difference in CO 2 fluxes can be attributed to lower sea surface temperatures and more extensive sea ice cover in 1997, and these observations were related to increased convection in the Greenland Sea during winter 1997. Larger amplitudes in the seasonal variations of CO 2 flux were also seen during the other seasons in the period 1996–97, compared to 1995. Over the years of investigation in the Greenland Sea, the carbon flux showed an increasing trend of 9·10 −4 Gt C yr −1 into the ocean, which may be related to the anthropogenic input of carbon to the atmosphere. The Greenland and Norwegian Seas appear to be sinks for atmospheric CO 2 and together absorb approximately 0.12 ± 0.015 Gt C yr −1 . DOI: 10.1034/j.1600-0889.1999.00024.x
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Pub Date : 1999-04-01DOI: 10.1034/J.1600-0889.1999.T01-1-00004.X
M. Bender, M. Battle
{"title":"KEYNOTE PERSPECTIVE. Carbon cycle studies based on the distribution of O 2 in air","authors":"M. Bender, M. Battle","doi":"10.1034/J.1600-0889.1999.T01-1-00004.X","DOIUrl":"https://doi.org/10.1034/J.1600-0889.1999.T01-1-00004.X","url":null,"abstract":"","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":"44 1","pages":"165-169"},"PeriodicalIF":2.3,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80254208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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