Pub Date : 1999-07-01DOI: 10.3402/TELLUSB.V51I3.16442
H. Mouri, Ippei Nagao, K. Okada, S. Koga, Hiroshi L. Tanaka
Samplings of aerosol particles were made almost monthly throughout a year at a coastal Antarctic station Syowa (69°00′S, 39°35′E). With X-ray spectrometry, elemental composition of the individual particles is studied. The dominant aerosol constituents are sulphur species and sea salt. They are internally mixed with each other in most cases. We find seasonal variations in (1) the relative importance of sulphur and sea salt, and (2) the modification of sea salt by acidic materials. In the austral-summer samples, the number fractions of sulphur-rich particles and modified sea-salt particles are high, because the production of marine organosulfer was enhanced. In the austral-winter samples, the number fraction of unmodified sea-salt particles is high, because severe storms enhanced the production of sea salt. DOI: 10.1034/j.1600-0889.1999.t01-2-00002.x
{"title":"Individual-particle analyses of coastal Antarctic aerosols","authors":"H. Mouri, Ippei Nagao, K. Okada, S. Koga, Hiroshi L. Tanaka","doi":"10.3402/TELLUSB.V51I3.16442","DOIUrl":"https://doi.org/10.3402/TELLUSB.V51I3.16442","url":null,"abstract":"Samplings of aerosol particles were made almost monthly throughout a year at a coastal Antarctic station Syowa (69°00′S, 39°35′E). With X-ray spectrometry, elemental composition of the individual particles is studied. The dominant aerosol constituents are sulphur species and sea salt. They are internally mixed with each other in most cases. We find seasonal variations in (1) the relative importance of sulphur and sea salt, and (2) the modification of sea salt by acidic materials. In the austral-summer samples, the number fractions of sulphur-rich particles and modified sea-salt particles are high, because the production of marine organosulfer was enhanced. In the austral-winter samples, the number fraction of unmodified sea-salt particles is high, because severe storms enhanced the production of sea salt. DOI: 10.1034/j.1600-0889.1999.t01-2-00002.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":"47 1","pages":"603-611"},"PeriodicalIF":2.3,"publicationDate":"1999-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91043654","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.V51I2.16276
C. Trudinger, I. Enting, R. Francey, D. Etheridge, P. Rayner
The new high precision Law Dome ice core record of CO 2 and δ 13 CO 2 is used with a 1-D global carbon cycle model to investigate natural variability in the carbon cycle and the anthropogenic CO 2 perturbation, focusing on variations on time-scales of centuries. A major feature of the ice core record is the decrease in CO 2 , and increase in δ 13 C, through the ‘‘Little Ice Age’′ period (roughly 1550–1800). We show that this observed decrease in CO 2 is consistent with the effect of decreased temperature on either terrestrial or oceanic exchange, however the increase in δ 13 C favors a terrestrial response to cooling. We perform single deconvolution model calculations which generally give good agreement with observed variations in CO 2 , δ 13 C and Δ 14 C data for different reservoirs and due to both natural and anthropogenic causes. The fit to prebomb Δ 14 C is improved by using an ice core 10 Be record to represent the natural production of 14 C due to cosmic rays, however, the uncertainties in interpreting the 10 Be are as yet too large to use prebomb Δ 14 C to better constrain the model parameters. DOI: 10.1034/j.1600-0889.1999.t01-1-00009.x
{"title":"Long‐term variability in the global carbon cycle inferred from a high‐precision CO2 and δ13C ice‐core record","authors":"C. Trudinger, I. Enting, R. Francey, D. Etheridge, P. Rayner","doi":"10.3402/TELLUSB.V51I2.16276","DOIUrl":"https://doi.org/10.3402/TELLUSB.V51I2.16276","url":null,"abstract":"The new high precision Law Dome ice core record of CO 2 and δ 13 CO 2 is used with a 1-D global carbon cycle model to investigate natural variability in the carbon cycle and the anthropogenic CO 2 perturbation, focusing on variations on time-scales of centuries. A major feature of the ice core record is the decrease in CO 2 , and increase in δ 13 C, through the ‘‘Little Ice Age’′ period (roughly 1550–1800). We show that this observed decrease in CO 2 is consistent with the effect of decreased temperature on either terrestrial or oceanic exchange, however the increase in δ 13 C favors a terrestrial response to cooling. We perform single deconvolution model calculations which generally give good agreement with observed variations in CO 2 , δ 13 C and Δ 14 C data for different reservoirs and due to both natural and anthropogenic causes. The fit to prebomb Δ 14 C is improved by using an ice core 10 Be record to represent the natural production of 14 C due to cosmic rays, however, the uncertainties in interpreting the 10 Be are as yet too large to use prebomb Δ 14 C to better constrain the model parameters. DOI: 10.1034/j.1600-0889.1999.t01-1-00009.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":"4 1","pages":"233-248"},"PeriodicalIF":2.3,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79225594","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.V51I2.16314
S. Yamamoto, S. Murayama, N. Saigusa, H. Kondo
The objective of this research is to elucidate the seasonal and inter-annual variations of CO 2 exchanges between the atmosphere and a temperate deciduous forest in Japan and to elucidate their relation to meteorological conditions. The uptake rates of CO 2 from October 1993 to December 1996 were estimated from field measurements of CO 2 concentrations and meteorological conditions using a tower. Net of uptake rate of CO 2 was positive (uptake by forest ecosystems) from June to September and negative (release to the air) from October to April. Averages of integrated uptake rates of CO 2 were 840, − 450 and 390 gCO 2 /m 2 /year (2.3, − 1.2 and 1.1 tC/ha/year) for daytime, night and whole day (net), but they had notable inter-annual variation due to the differences of averaged insolation and temperature each summer of 1994 to 1996. The errors of CO 2 flux due to topographical conditions were investigated through comparison with heat budgets. CO 2 uptake rate estimated by tower measurement might be underestimation of 40%, therefore, above net-uptake value, 1.1 tC/ha/year became 1.8. This value of uptake rate was smaller than the results obtained in other temperate deciduous forests. The causes of this are partially in the difference of the height of the site and the short active period of the present forest. According to the CO 2 flux measurements in several forests including the present one, the forest ecosystems could be a large sink of CO 2 , however, more data of the CO 2 flux is needed at the various forests and latitudes to reduce the uncertainty of estimation of CO 2 uptake on a global scale. DOI: 10.1034/j.1600-0889.1999.00020.x
{"title":"Seasonal and inter-annual variation of CO2 flux between a temperate forest and the atmosphere in Japan","authors":"S. Yamamoto, S. Murayama, N. Saigusa, H. Kondo","doi":"10.3402/TELLUSB.V51I2.16314","DOIUrl":"https://doi.org/10.3402/TELLUSB.V51I2.16314","url":null,"abstract":"The objective of this research is to elucidate the seasonal and inter-annual variations of CO 2 exchanges between the atmosphere and a temperate deciduous forest in Japan and to elucidate their relation to meteorological conditions. The uptake rates of CO 2 from October 1993 to December 1996 were estimated from field measurements of CO 2 concentrations and meteorological conditions using a tower. Net of uptake rate of CO 2 was positive (uptake by forest ecosystems) from June to September and negative (release to the air) from October to April. Averages of integrated uptake rates of CO 2 were 840, − 450 and 390 gCO 2 /m 2 /year (2.3, − 1.2 and 1.1 tC/ha/year) for daytime, night and whole day (net), but they had notable inter-annual variation due to the differences of averaged insolation and temperature each summer of 1994 to 1996. The errors of CO 2 flux due to topographical conditions were investigated through comparison with heat budgets. CO 2 uptake rate estimated by tower measurement might be underestimation of 40%, therefore, above net-uptake value, 1.1 tC/ha/year became 1.8. This value of uptake rate was smaller than the results obtained in other temperate deciduous forests. The causes of this are partially in the difference of the height of the site and the short active period of the present forest. According to the CO 2 flux measurements in several forests including the present one, the forest ecosystems could be a large sink of CO 2 , however, more data of the CO 2 flux is needed at the various forests and latitudes to reduce the uncertainty of estimation of CO 2 uptake on a global scale. DOI: 10.1034/j.1600-0889.1999.00020.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":"10 1","pages":"402-413"},"PeriodicalIF":2.3,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75250975","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.V51I2.16286
B. A. S. Denning, M. Holzer, K. Gurney, M. Heimann, R. Law, P. Rayner, I. Fung, S. Fan, Shoichi, Taguchi, P. Friedlingstein, Y. Balkanski, John A. Taylor, Manfred, Maiss, I. Levin
Sulfur hexafluoride (SF 6 ) is an excellent tracer of large-scale atmospheric transport, because it has slowly increasing sources mostly confined to northern midlatitudes, and has a lifetime of thousands of years. We have simulated the emissions, transport, and concentration of SF 6 for a 5-year period, and compared the results with atmospheric observations. In addition, we have performed an intercomparison of interhemispheric transport among 11 models to investigate the reasons for the diVerences among the simulations. Most of the models are reasonably successful at simulating the observed meridional gradient of SF 6 in the remote marine boundary layer, though there is less agreement at continental sites. Models that compare well to observations in the remote marine boundary layer tend to systematically overestimate SF 6 at continental locations in source regions, suggesting that vertical trapping rather than meridional transport may be a dominant control on the simulated meridional gradient. The vertical structure of simulated SF 6 in the models supports this interpretation. Some of the models perform quite well in terms of the simulated seasonal cycle at remote locations, while others do not. Interhemispheric exchange time varies by a factor of 2 when estimated from 1-dimensional meridional profiles at the surface, as has been done for observations. The agreement among models is better when the global surface mean mole fraction is used, and better still when the full 3-dimensional mean mixing ratio is used. The ranking of the interhemispheric exchange time among the models is not sensitive to the change from station values to surface means, but is very sensitive to the change from surface means to the full 3-dimensional tracer fields. This strengthens the argument that vertical redistribution dominates over interhemispheric transport in determining the meridional gradient at the surface. Vertically integrated meridional transport in the models is divided roughly equally into transport by the mean motion, the standing eddies, and the transient eddies. The vertically integrated mass flux is a good index of the degree to
{"title":"Three-dimensional transport and concentration of SF6. A model intercomparison study (TransCom 2)","authors":"B. A. S. Denning, M. Holzer, K. Gurney, M. Heimann, R. Law, P. Rayner, I. Fung, S. Fan, Shoichi, Taguchi, P. Friedlingstein, Y. Balkanski, John A. Taylor, Manfred, Maiss, I. Levin","doi":"10.3402/TELLUSB.V51I2.16286","DOIUrl":"https://doi.org/10.3402/TELLUSB.V51I2.16286","url":null,"abstract":"Sulfur hexafluoride (SF 6 ) is an excellent tracer of large-scale atmospheric transport, because it has slowly increasing sources mostly confined to northern midlatitudes, and has a lifetime of thousands of years. We have simulated the emissions, transport, and concentration of SF 6 for a 5-year period, and compared the results with atmospheric observations. In addition, we have performed an intercomparison of interhemispheric transport among 11 models to investigate the reasons for the diVerences among the simulations. Most of the models are reasonably successful at simulating the observed meridional gradient of SF 6 in the remote marine boundary layer, though there is less agreement at continental sites. Models that compare well to observations in the remote marine boundary layer tend to systematically overestimate SF 6 at continental locations in source regions, suggesting that vertical trapping rather than meridional transport may be a dominant control on the simulated meridional gradient. The vertical structure of simulated SF 6 in the models supports this interpretation. Some of the models perform quite well in terms of the simulated seasonal cycle at remote locations, while others do not. Interhemispheric exchange time varies by a factor of 2 when estimated from 1-dimensional meridional profiles at the surface, as has been done for observations. The agreement among models is better when the global surface mean mole fraction is used, and better still when the full 3-dimensional mean mixing ratio is used. The ranking of the interhemispheric exchange time among the models is not sensitive to the change from station values to surface means, but is very sensitive to the change from surface means to the full 3-dimensional tracer fields. This strengthens the argument that vertical redistribution dominates over interhemispheric transport in determining the meridional gradient at the surface. Vertically integrated meridional transport in the models is divided roughly equally into transport by the mean motion, the standing eddies, and the transient eddies. The vertically integrated mass flux is a good index of the degree to","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":"56 1","pages":"266-297"},"PeriodicalIF":2.3,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84753830","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.1600-0889.1999.00027.X
R. Wanninkhof, S. Doney, T. Peng, J. L. Bullister, Kitack Lee, R. Feely
A comparison of different methods for estimating the anthropogenic CO 2 burden in the Atlantic Ocean is performed using referenced, high quality total dissolved inorganic carbon (DIC) data. The dataset is from two cruises through the center of the basin between 62°N and 43°S in 1991 and 1993. The specific anthropogenic input is determined utilizing empirical procedures as described in Gruber et al. (1996) and Chen and Millero (1979) to correct for remineralization and to estimate preanthropogenic endmembers. These estimates are compared with output of the Princeton ocean biogeochemical model and the NCAR ocean model. The results show that the specific inventories of anthropogenic carbon agree to within 20% but with different storage and uptake patterns. The empirical estimates differ because of assumptions about mixing and winter outcrop endmembers. The same remineralization quotients (Redfield ratios) were used for each method. Varying these constants within the range of literature values causes changes in specific inventories of similar magnitude as the differences observed with different methodologies. Comparison of anthropogenic CO 2 uptake and chlorofluorocarbon ages suggests that the anthropogenic CO 2 penetration in the North Atlantic is too shallow following the procedure according to Gruber et al. (1996), and too deep using those of Chen and Millero (1979). The results support these previous observations in that the uptake of CO 2 in the North Atlantic is disproportionate to its surface area. This is caused by a combination of deep water formation and deep winter mixed layers. DOI: 10.1034/j.1600-0889.1999.00027.x
{"title":"Comparison of methods to determine the anthropogenic CO2 invasion into the Atlantic Ocean","authors":"R. Wanninkhof, S. Doney, T. Peng, J. L. Bullister, Kitack Lee, R. Feely","doi":"10.1034/J.1600-0889.1999.00027.X","DOIUrl":"https://doi.org/10.1034/J.1600-0889.1999.00027.X","url":null,"abstract":"A comparison of different methods for estimating the anthropogenic CO 2 burden in the Atlantic Ocean is performed using referenced, high quality total dissolved inorganic carbon (DIC) data. The dataset is from two cruises through the center of the basin between 62°N and 43°S in 1991 and 1993. The specific anthropogenic input is determined utilizing empirical procedures as described in Gruber et al. (1996) and Chen and Millero (1979) to correct for remineralization and to estimate preanthropogenic endmembers. These estimates are compared with output of the Princeton ocean biogeochemical model and the NCAR ocean model. The results show that the specific inventories of anthropogenic carbon agree to within 20% but with different storage and uptake patterns. The empirical estimates differ because of assumptions about mixing and winter outcrop endmembers. The same remineralization quotients (Redfield ratios) were used for each method. Varying these constants within the range of literature values causes changes in specific inventories of similar magnitude as the differences observed with different methodologies. Comparison of anthropogenic CO 2 uptake and chlorofluorocarbon ages suggests that the anthropogenic CO 2 penetration in the North Atlantic is too shallow following the procedure according to Gruber et al. (1996), and too deep using those of Chen and Millero (1979). The results support these previous observations in that the uptake of CO 2 in the North Atlantic is disproportionate to its surface area. This is caused by a combination of deep water formation and deep winter mixed layers. DOI: 10.1034/j.1600-0889.1999.00027.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":"54 1","pages":"511-530"},"PeriodicalIF":2.3,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78844160","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.V51I2.16269
R. Francey, R. Francey, C. Allison, D. Etheridge, C. Trudinger, C. Trudinger, I. Enting, I. Enting, M. Leuenberger, R. Langenfelds, E. Michel, L. Steele, L. Steele
We present measurements of the stable carbon isotope ratio in air extracted from Antarctic ice core and firn samples. The same samples were previously used by Etheridge and co-workers to construct a high precision 1000-year record of atmospheric CO 2 concentration, featuring a close link between the ice and modern records and high-time resolution. Here, we start by confirming the trend in the Cape Grim in situ δ 13 C record from 1982 to 1996, and extend it back to 1978 using the Cape Grim Air Archive. The firn air δ 13 C agrees with the Cape Grim record, but only after correction for gravitational separation at depth, for diffusion effects associated with disequilibrium between the atmosphere and firm, and allowance for a latidudinal gradient in δ 13 C between Cape Grim and the Antarctic coast. Complex calibration strategies are required to cope with several additional systematic influences on the ice core δ 13 C record. Errors are assigned to each ice core value to reflect statistical and systematic biases (between ± 0.025‰ and ± 0.07‰); uncertainties (of up to ± 0.05‰) between core-versus-core, ice-versus-firn and firn-versus-troposphere are described separately. An almost continuous atmospheric history of δ 13 C over 1000 years results, exhibiting significant decadal-to-century scale variability unlike that from earlier proxy records. The decrease in δ 13 C from 1860 to 1960 involves a series of steps confirming enhanced sensitivity of δ 13 C to decadal timescale-forcing, compared to the CO 2 record. Synchronous with a ‘‘Little Ice Age’′ CO 2 decrease, an enhancement of δ 13 C implies a terrestrial response to cooler temperatures. Between 1200 AD and 1600 AD, the atmospheric δ 13 C appear stable. DOI: 10.1034/j.1600-0889.1999.t01-1-00005.x
{"title":"A 1000-year high precision record of δ 13 C in atmospheric CO 2","authors":"R. Francey, R. Francey, C. Allison, D. Etheridge, C. Trudinger, C. Trudinger, I. Enting, I. Enting, M. Leuenberger, R. Langenfelds, E. Michel, L. Steele, L. Steele","doi":"10.3402/TELLUSB.V51I2.16269","DOIUrl":"https://doi.org/10.3402/TELLUSB.V51I2.16269","url":null,"abstract":"We present measurements of the stable carbon isotope ratio in air extracted from Antarctic ice core and firn samples. The same samples were previously used by Etheridge and co-workers to construct a high precision 1000-year record of atmospheric CO 2 concentration, featuring a close link between the ice and modern records and high-time resolution. Here, we start by confirming the trend in the Cape Grim in situ δ 13 C record from 1982 to 1996, and extend it back to 1978 using the Cape Grim Air Archive. The firn air δ 13 C agrees with the Cape Grim record, but only after correction for gravitational separation at depth, for diffusion effects associated with disequilibrium between the atmosphere and firm, and allowance for a latidudinal gradient in δ 13 C between Cape Grim and the Antarctic coast. Complex calibration strategies are required to cope with several additional systematic influences on the ice core δ 13 C record. Errors are assigned to each ice core value to reflect statistical and systematic biases (between ± 0.025‰ and ± 0.07‰); uncertainties (of up to ± 0.05‰) between core-versus-core, ice-versus-firn and firn-versus-troposphere are described separately. An almost continuous atmospheric history of δ 13 C over 1000 years results, exhibiting significant decadal-to-century scale variability unlike that from earlier proxy records. The decrease in δ 13 C from 1860 to 1960 involves a series of steps confirming enhanced sensitivity of δ 13 C to decadal timescale-forcing, compared to the CO 2 record. Synchronous with a ‘‘Little Ice Age’′ CO 2 decrease, an enhancement of δ 13 C implies a terrestrial response to cooler temperatures. Between 1200 AD and 1600 AD, the atmospheric δ 13 C appear stable. DOI: 10.1034/j.1600-0889.1999.t01-1-00005.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":"118 1","pages":"170-193"},"PeriodicalIF":2.3,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89859650","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.V51I2.16288
R. Houghton
Rates of land-use change, including clearing for agriculture and harvest of wood, were reconstructed from statistical and historic documents for 9 world regions and used, along with the per ha changes in vegetation and soil that result from land management, to calculate the annual flux of carbon between land and atmosphere. Between 1850 and 1990, changes in land use are calculated to have added 124 PgC to the atmosphere, about half as much as released from combustion of fossil fuels over this period. About 108 PgC are estimated to have been transferred from forests to the atmosphere as a result of human activity, 2/3 from tropical forests and 1/3 from temperate zone and boreal forests. Another 16 PgC were lost from non-forests, largely as a result of cultivation of mid-latitude grassland soils. About 800 × 10 6 ha of forest were cleared for agricultural purposes, and approximately 2000 × 10 6 ha were harvested. Conversion of forests to agricultural lands released 105 PgC; harvest of wood released about 20 PgC. These estimates of release include the accumulations of carbon in wood products (17 PgC) and woody debris (4 PgC), the losses of carbon from oxidation of wood products, woody debris, and soil organic matter (373 PgC in total), and the accumulations of carbon in forests recovering from harvest and in the fallows of shifting cultivation (249 PgC). Over the decade of the 1980s the annual net flux of carbon from changes in land use averaged about 2.0 PgC yr −1 , higher than the 1.6 PgC yr −1 estimated previously. Almost all of this flux was from tropical regions, where rates of deforestation averaged approximately 15 × 10 6 ha yr −1 . Outside the tropics, regrowth of forests logged in earlier years largely balanced the losses of carbon from oxidation of wood products. DOI: 10.1034/j.1600-0889.1999.00013.x
根据9个世界区域的统计和历史文件重建了土地利用变化率，包括开垦农业用地和砍伐木材，并将其与土地管理导致的每公顷植被和土壤变化一起用于计算土地和大气之间的年碳通量。据计算，在1850年至1990年间，土地利用的变化向大气中增加了124种PgC，大约是同期化石燃料燃烧释放的PgC的一半。据估计，由于人类活动，大约有108种PgC从森林转移到大气中，其中2/3来自热带森林，1/3来自温带和北方森林。另外16个PgC来自非森林，主要是由于中纬度草地土壤的种植。大约800 × 10.6公顷的森林被砍伐用于农业，大约2000 × 10.6公顷的森林被采伐。退耕还林释放105 PgC;收获的木材释放约20 PgC。这些释放估计包括木制品(17 PgC)和木屑(4 PgC)中的碳积累，木制品、木屑和土壤有机质氧化导致的碳损失(总共373 PgC)，以及采伐后恢复的森林和轮作休耕地中的碳积累(249 PgC)。在20世纪80年代的十年中，土地利用变化产生的年净碳通量平均约为2.0 PgC /年，高于先前估计的1.6 PgC /年。几乎所有这些通量都来自热带地区，那里的森林砍伐率平均约为15 × 106公顷/年。在热带地区以外，早期砍伐的森林的再生在很大程度上平衡了木材产品氧化造成的碳损失。DOI: 10.1034 / j.1600-0889.1999.00013.x
{"title":"The annual net flux of carbon to the atmosphere from changes in land use 1850–1990*","authors":"R. Houghton","doi":"10.3402/TELLUSB.V51I2.16288","DOIUrl":"https://doi.org/10.3402/TELLUSB.V51I2.16288","url":null,"abstract":"Rates of land-use change, including clearing for agriculture and harvest of wood, were reconstructed from statistical and historic documents for 9 world regions and used, along with the per ha changes in vegetation and soil that result from land management, to calculate the annual flux of carbon between land and atmosphere. Between 1850 and 1990, changes in land use are calculated to have added 124 PgC to the atmosphere, about half as much as released from combustion of fossil fuels over this period. About 108 PgC are estimated to have been transferred from forests to the atmosphere as a result of human activity, 2/3 from tropical forests and 1/3 from temperate zone and boreal forests. Another 16 PgC were lost from non-forests, largely as a result of cultivation of mid-latitude grassland soils. About 800 × 10 6 ha of forest were cleared for agricultural purposes, and approximately 2000 × 10 6 ha were harvested. Conversion of forests to agricultural lands released 105 PgC; harvest of wood released about 20 PgC. These estimates of release include the accumulations of carbon in wood products (17 PgC) and woody debris (4 PgC), the losses of carbon from oxidation of wood products, woody debris, and soil organic matter (373 PgC in total), and the accumulations of carbon in forests recovering from harvest and in the fallows of shifting cultivation (249 PgC). Over the decade of the 1980s the annual net flux of carbon from changes in land use averaged about 2.0 PgC yr −1 , higher than the 1.6 PgC yr −1 estimated previously. Almost all of this flux was from tropical regions, where rates of deforestation averaged approximately 15 × 10 6 ha yr −1 . Outside the tropics, regrowth of forests logged in earlier years largely balanced the losses of carbon from oxidation of wood products. DOI: 10.1034/j.1600-0889.1999.00013.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":"577 1","pages":"298-313"},"PeriodicalIF":2.3,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80003729","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.1600-0889.1999.00029.X
F. Louanchi, M. Hoppema, D. Bakker, A. Poisson, M. Stoll, H. Baar, B. Schauer, D. Ruiz-Pino, D. Wolf-Gladrow
The results of an existing one-dimensional diagnostic model that calculates the fugacity of CO 2 (fCO 2 ) in the surface layer of the southern ocean were compared with in situ observations from different ocean sectors and seasons. Our model is based on the translation of monthly variations of constraints fields into surface water fCO 2 variations, and was used to assess the CO 2 uptake of the southern ocean. In situ observations are useful to verify the model results and were here applied to improve the estimation of the CO 2 uptake of the southern ocean south of 50 S. The model reproduces the fCO 2 distribution in both Pacific and Indian sectors of the southern ocean satisfactorily, the mean deviation being only 5 μatm. This diserepancy requires only a minor modification of the CO 2 uptake calculated by the model for that area. By contrast, the model strongly underestimates the fCO 2 levels in carly spring and early winter in the Weddell gyre. This indicates that the CO 2 uptake by the Atlantic sector of the southern ocean as calculated by the model, amounting to 0.47 GtC yr -1 . should be reduced, possibly by about half of this value. The reason for this mismatch lies in the use of climatological physical constraints by the model, that do not sufficiently well describe reality. Partly, the mismatch is also caused by a difference of seasonal stage between the model which reflects climatological conditions and the real ocean which is affected by interannual variability. Based on this study it is concluded that the CO 2 uptake of the southern ocean south of 50 S is likely to lie somewhere between 0.6 and 0.7 GtC yr -1 for the 1990s, which is a high value compared to estimates from other investigations.
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Pub Date : 1999-04-01DOI: 10.3402/TELLUSB.V51I2.16271
P. Rayner, R. Law
(1999). The interannual variability of the global carbon cycle. Tellus B: Chemical and Physical Meteorology: Vol. 51, No. 2, pp. 210-212.
(1999)。全球碳循环的年际变化。《化学与物理气象学》，第51卷第2期，页210-212。
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Pub Date : 1999-04-01DOI: 10.3402/TELLUSB.V51I2.16309
C. Häger, G. Würth, G. Kohlmaier
In this contribution, we perform a case study of the German forests. We couple the Frankfurt biosphere model (FBM) with a model of the age class development (AGEDYN). The coupled model is applied to simulate the temporal development of carbon pools in German forests under the influence of climate change taking into account changes in the age class structure. In the base case, the growth of forest stands is simulated using a temporally averaged climate dataset, being representative for the contemporary climate conditions. To assess the sensitivity of forest growth to changes in environmental conditions, the FBM is run in several scenarios. In these simulations the effects both of climate change and of the direct effect of increased levels of atmospheric CO 2 on photosynthesis (CO 2 fertilization) on forest growth are assessed. In another simulation run with the FBM both effects — climate change and CO 2 fertilization — are combined. In simulations under present day's climate conditions a good agreement is gained between simulation results and statistical data of the present standing stock carbon density of Germany's forests. A pure climate change leads to a decrease of the annual increments as well as to the climax standing stocks. The negative effect of climate change alone is overcompensated by enhanced photosynthesis in the simulations with combined climate change and CO 2 fertilization. In the transient case, the coupled model is used in two scenarios describing first a continuation of present day's climate conditions and second a transient climate change from present conditions (1990) to 2 × CO 2 conditions in 2090. Here, the simulations indicate that changes in the forest's age class structure can have a stronger influence on the future carbon balance of the forests in the considered region than the combined efffect of climate change and CO 2 fertilization. DOI: 10.1034/j.1600-0889.1999.00019.x
{"title":"Biomass of forest stands under climatic change: a German case study with the Frankfurt biosphere model (FBM)","authors":"C. Häger, G. Würth, G. Kohlmaier","doi":"10.3402/TELLUSB.V51I2.16309","DOIUrl":"https://doi.org/10.3402/TELLUSB.V51I2.16309","url":null,"abstract":"In this contribution, we perform a case study of the German forests. We couple the Frankfurt biosphere model (FBM) with a model of the age class development (AGEDYN). The coupled model is applied to simulate the temporal development of carbon pools in German forests under the influence of climate change taking into account changes in the age class structure. In the base case, the growth of forest stands is simulated using a temporally averaged climate dataset, being representative for the contemporary climate conditions. To assess the sensitivity of forest growth to changes in environmental conditions, the FBM is run in several scenarios. In these simulations the effects both of climate change and of the direct effect of increased levels of atmospheric CO 2 on photosynthesis (CO 2 fertilization) on forest growth are assessed. In another simulation run with the FBM both effects — climate change and CO 2 fertilization — are combined. In simulations under present day's climate conditions a good agreement is gained between simulation results and statistical data of the present standing stock carbon density of Germany's forests. A pure climate change leads to a decrease of the annual increments as well as to the climax standing stocks. The negative effect of climate change alone is overcompensated by enhanced photosynthesis in the simulations with combined climate change and CO 2 fertilization. In the transient case, the coupled model is used in two scenarios describing first a continuation of present day's climate conditions and second a transient climate change from present conditions (1990) to 2 × CO 2 conditions in 2090. Here, the simulations indicate that changes in the forest's age class structure can have a stronger influence on the future carbon balance of the forests in the considered region than the combined efffect of climate change and CO 2 fertilization. DOI: 10.1034/j.1600-0889.1999.00019.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":"1 1","pages":"385-401"},"PeriodicalIF":2.3,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89368406","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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