Pub Date : 2017-01-01Epub Date: 2017-04-03DOI: 10.1080/16000889.2017.1291158
T Shirai, M Ishizawa, R Zhuravlev, A Ganshin, D Belikov, M Saito, T Oda, V Valsala, A J Gomez-Pelaez, R Langenfelds, S Maksyutov
We present an assimilation system for atmospheric carbon dioxide (CO2) using a Global Eulerian-Lagrangian Coupled Atmospheric model (GELCA), and demonstrate its capability to capture the observed atmospheric CO2 mixing ratios and to estimate CO2 fluxes. With the efficient data handling scheme in GELCA, our system assimilates non-smoothed CO2 data from observational data products such as the Observation Package (ObsPack) data products as constraints on surface fluxes. We conducted sensitivity tests to examine the impact of the site selections and the prior uncertainty settings of observation on the inversion results. For these sensitivity tests, we made five different site/data selections from the ObsPack product. In all cases, the time series of the global net CO2 flux to the atmosphere stayed close to values calculated from the growth rate of the observed global mean atmospheric CO2 mixing ratio. At regional scales, estimated seasonal CO2 fluxes were altered, depending on the CO2 data selected for assimilation. Uncertainty reductions (URs) were determined at the regional scale and compared among cases. As measures of the model-data mismatch, we used the model-data bias, root-mean-square error, and the linear correlation. For most observation sites, the model-data mismatch was reasonably small. Regarding regional flux estimates, tropical Asia was one of the regions that showed a significant impact from the observation network settings. We found that the surface fluxes in tropical Asia were the most sensitive to the use of aircraft measurements over the Pacific, and the seasonal cycle agreed better with the results of bottom-up studies when the aircraft measurements were assimilated. These results confirm the importance of these aircraft observations, especially for constraining surface fluxes in the tropics.
{"title":"A decadal inversion of CO<sub>2</sub> using the Global Eulerian-Lagrangian Coupled Atmospheric model (GELCA): sensitivity to the ground-based observation network.","authors":"T Shirai, M Ishizawa, R Zhuravlev, A Ganshin, D Belikov, M Saito, T Oda, V Valsala, A J Gomez-Pelaez, R Langenfelds, S Maksyutov","doi":"10.1080/16000889.2017.1291158","DOIUrl":"https://doi.org/10.1080/16000889.2017.1291158","url":null,"abstract":"<p><p>We present an assimilation system for atmospheric carbon dioxide (CO<sub>2</sub>) using a Global Eulerian-Lagrangian Coupled Atmospheric model (GELCA), and demonstrate its capability to capture the observed atmospheric CO<sub>2</sub> mixing ratios and to estimate CO<sub>2</sub> fluxes. With the efficient data handling scheme in GELCA, our system assimilates non-smoothed CO<sub>2</sub> data from observational data products such as the Observation Package (ObsPack) data products as constraints on surface fluxes. We conducted sensitivity tests to examine the impact of the site selections and the prior uncertainty settings of observation on the inversion results. For these sensitivity tests, we made five different site/data selections from the ObsPack product. In all cases, the time series of the global net CO<sub>2</sub> flux to the atmosphere stayed close to values calculated from the growth rate of the observed global mean atmospheric CO<sub>2</sub> mixing ratio. At regional scales, estimated seasonal CO<sub>2</sub> fluxes were altered, depending on the CO<sub>2</sub> data selected for assimilation. Uncertainty reductions (URs) were determined at the regional scale and compared among cases. As measures of the model-data mismatch, we used the model-data bias, root-mean-square error, and the linear correlation. For most observation sites, the model-data mismatch was reasonably small. Regarding regional flux estimates, tropical Asia was one of the regions that showed a significant impact from the observation network settings. We found that the surface fluxes in tropical Asia were the most sensitive to the use of aircraft measurements over the Pacific, and the seasonal cycle agreed better with the results of bottom-up studies when the aircraft measurements were assimilated. These results confirm the importance of these aircraft observations, especially for constraining surface fluxes in the tropics.</p>","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/16000889.2017.1291158","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38311412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-09-01DOI: 10.3402/TELLUSB.V63I4.16347
A. Schladitz, T. Müller, S. Nordmann, M. Tesche, S. Groß, V. Freudenthaler, J. Gasteiger, A. Wiedensohler
An observation-based numerical study of humidity-dependent aerosol optical properties of mixed marine and Saharan mineral dust aerosol is presented. An aerosol model was developed based on measured optical and microphysical properties to describe the marine and Saharan dust aerosol at Cape Verde. A wavelength-dependent optical equivalent imaginary part of the refractive index and a scattering non-sphericity factor for Saharan dust were derived. Simulations of humidity effects on optical properties by the aerosol model were validated with relative measurements of the extinction coefficient at ambient conditions. Parametrizations were derived to describe the humidity dependence of the extinction, scattering, and absorption coefficients as well as the asymmetry parameter and single scattering albedo. For wavelengths (300–950 nm) and dry dust volume fractions (0–1), aerosol optical properties as a function of relative humidity (RH = 0–90%) can be calculated from tabulated parameters. For instance, at a wavelength of 550 nm, a volume fraction of 0.5 of dust on the total particle volume (dry conditions) and a RH of 90%, the enhancements for the scattering, extinction and absorption coefficients are 2.55, 2.46 and 1.04, respectively, while the enhancements for the asymmetry parameter and single scattering albedo are 1.11 and 1.04. DOI: 10.1111/j.1600-0889.2011.00568.x
{"title":"In situ aerosol characterization at Cape Verde Part 2: Parametrization of relative humidity- and wavelength-dependent aerosol optical properties","authors":"A. Schladitz, T. Müller, S. Nordmann, M. Tesche, S. Groß, V. Freudenthaler, J. Gasteiger, A. Wiedensohler","doi":"10.3402/TELLUSB.V63I4.16347","DOIUrl":"https://doi.org/10.3402/TELLUSB.V63I4.16347","url":null,"abstract":"An observation-based numerical study of humidity-dependent aerosol optical properties of mixed marine and Saharan mineral dust aerosol is presented. An aerosol model was developed based on measured optical and microphysical properties to describe the marine and Saharan dust aerosol at Cape Verde. A wavelength-dependent optical equivalent imaginary part of the refractive index and a scattering non-sphericity factor for Saharan dust were derived. Simulations of humidity effects on optical properties by the aerosol model were validated with relative measurements of the extinction coefficient at ambient conditions. Parametrizations were derived to describe the humidity dependence of the extinction, scattering, and absorption coefficients as well as the asymmetry parameter and single scattering albedo. For wavelengths (300–950 nm) and dry dust volume fractions (0–1), aerosol optical properties as a function of relative humidity (RH = 0–90%) can be calculated from tabulated parameters. For instance, at a wavelength of 550 nm, a volume fraction of 0.5 of dust on the total particle volume (dry conditions) and a RH of 90%, the enhancements for the scattering, extinction and absorption coefficients are 2.55, 2.46 and 1.04, respectively, while the enhancements for the asymmetry parameter and single scattering albedo are 1.11 and 1.04. DOI: 10.1111/j.1600-0889.2011.00568.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2011-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80399497","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 : 2011-01-01DOI: 10.3402/TELLUSB.V63I4.16345
A. Schladitz, T. Müller, A. Nowak, K. Kandler, K. Lieke, A. Massling, A. Wiedensohler
Particle number size distributions and hygroscopic properties of marine and Saharan dust aerosol were investigated during the SAMUM-2 field study at Cape Verde in winter 2008. Aitken and accumulation mode particles were mainly assigned to the marine aerosol, whereas coarse mode particles were composed of sea-salt and a variable fraction of Saharan mineral dust. A new methodical approach was used to derive hygroscopic growth and state of mixing for a particle size range (volume equivalent) from dp ve = 26 nm to 10 μm. For hygroscopic particles with dp ve 250 nm. The mixing state of Saharan dust in terms of the number fraction of nearly hydrophobic particles showed the highest variation and ranges from 0.3 to almost 1. This study was used to perform a successful mass closure at ambient conditions and demonstrates the important role of hygroscopic growth of large sea-salt particles. DOI: 10.1111/j.1600-0889.2011.00569.x
{"title":"In situ aerosol characterization at Cape Verde. Part 1: Particle number size distributions, hygroscopic growth and state of mixing of the marine and Saharan dust aerosol","authors":"A. Schladitz, T. Müller, A. Nowak, K. Kandler, K. Lieke, A. Massling, A. Wiedensohler","doi":"10.3402/TELLUSB.V63I4.16345","DOIUrl":"https://doi.org/10.3402/TELLUSB.V63I4.16345","url":null,"abstract":"Particle number size distributions and hygroscopic properties of marine and Saharan dust aerosol were investigated during the SAMUM-2 field study at Cape Verde in winter 2008. Aitken and accumulation mode particles were mainly assigned to the marine aerosol, whereas coarse mode particles were composed of sea-salt and a variable fraction of Saharan mineral dust. A new methodical approach was used to derive hygroscopic growth and state of mixing for a particle size range (volume equivalent) from dp ve = 26 nm to 10 μm. For hygroscopic particles with dp ve 250 nm. The mixing state of Saharan dust in terms of the number fraction of nearly hydrophobic particles showed the highest variation and ranges from 0.3 to almost 1. This study was used to perform a successful mass closure at ambient conditions and demonstrates the important role of hygroscopic growth of large sea-salt particles. DOI: 10.1111/j.1600-0889.2011.00569.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90512987","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 : 2010-11-01DOI: 10.3402/TELLUSB.V62I5.16581
C. Alden, John B. Miller, J. White
The rare stable carbon isotope, 13 C, has been used previously to partition CO 2 fluxes into land and ocean components. Net ocean and land fluxes impose distinctive and predictable fractionation patterns upon the stable isotope ratio, making it an excellent tool for distinguishing between them. Historically, isotope constrained inverse methods for calculating CO 2 surface fluxes—the ‘double deconvolution’—have disagreed with bottom-up ocean flux estimates. In this study, we use the double deconvolution framework, but add, as a constraint, independent estimates of time histories of ocean fluxes to the atmospheric observations of CO 2 and 13 CO 2 . We calculate timeseries of net land flux, total disequilibrium flux and terrestrial disequilibrium flux from 1991 to 2008 that are consistent with bottom-up net ocean fluxes. We investigate possible drivers of interannual variability in terrestrial disequilibrium flux, including terrestrial discrimination, and test the sensitivity of our results to those mechanisms. We find that C 3 plant discrimination and shifts in the global composition of C 3 and C 4 vegetation are likely drivers of interannual variability in terrestrial disequilibrium flux, while contributions from heterotrophic respiration and disturbance anomalies are also possible. DOI: 10.1111/j.1600-0889.2010.00481.x
{"title":"Can bottom-up ocean CO 2 fluxes be reconciled with atmospheric 13 C observations?","authors":"C. Alden, John B. Miller, J. White","doi":"10.3402/TELLUSB.V62I5.16581","DOIUrl":"https://doi.org/10.3402/TELLUSB.V62I5.16581","url":null,"abstract":"The rare stable carbon isotope, 13 C, has been used previously to partition CO 2 fluxes into land and ocean components. Net ocean and land fluxes impose distinctive and predictable fractionation patterns upon the stable isotope ratio, making it an excellent tool for distinguishing between them. Historically, isotope constrained inverse methods for calculating CO 2 surface fluxes—the ‘double deconvolution’—have disagreed with bottom-up ocean flux estimates. In this study, we use the double deconvolution framework, but add, as a constraint, independent estimates of time histories of ocean fluxes to the atmospheric observations of CO 2 and 13 CO 2 . We calculate timeseries of net land flux, total disequilibrium flux and terrestrial disequilibrium flux from 1991 to 2008 that are consistent with bottom-up net ocean fluxes. We investigate possible drivers of interannual variability in terrestrial disequilibrium flux, including terrestrial discrimination, and test the sensitivity of our results to those mechanisms. We find that C 3 plant discrimination and shifts in the global composition of C 3 and C 4 vegetation are likely drivers of interannual variability in terrestrial disequilibrium flux, while contributions from heterotrophic respiration and disturbance anomalies are also possible. DOI: 10.1111/j.1600-0889.2010.00481.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2010-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84675364","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 : 2010-11-01DOI: 10.3402/TELLUSB.V62I5.16607
N. Lefèvre, D. Diverrés, F. Gallois
{"title":"Origin of CO2undersaturation in the western tropical Atlantic","authors":"N. Lefèvre, D. Diverrés, F. Gallois","doi":"10.3402/TELLUSB.V62I5.16607","DOIUrl":"https://doi.org/10.3402/TELLUSB.V62I5.16607","url":null,"abstract":"","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2010-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76691569","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 : 2009-04-01DOI: 10.1111/J.1600-0889.2008.00412.X
J. Ström, Ann-Christine Engvall, F. Delbart, R. Krejci, R. Treffeisen
Concurrent observations of particle number densities and size distributions observed at two different heights (near ocean level and 475 m above sea level) in Ny-Alesund, Svalbard were studied with respect to the diurnal variation during a summer period in June 2004. The results show that observed variation in particle number density in the Arctic boundary layer may be strongly modulated by vertical mixing and dilution. The particles appeared to be formed in the early morning when solar intensity reached about 30% of the mid-day intensity. Based on differences in the observed number densities at the two heights it appears as if particles are formed in the lower part of the boundary layer. The formation rate of 10 nm diameter particles is estimated to be 0.11 cm -3 s -1 and the growth rate is in a range between 1 and 2 nm h -1 . DOI: 10.1111/j.1600-0889.2008.00412.x
研究了2004年6月夏季在斯瓦尔巴群岛新奥勒松两个不同高度(近海平面和海拔475 m)同时观测到的颗粒数密度和粒径分布的日变化。结果表明，观测到的北极边界层粒子数密度变化可能受到垂直混合和稀释的强烈调制。这些粒子似乎是在太阳强度达到正午强度30%左右的清晨形成的。根据在两个高度观测到的数密度的差异，似乎粒子是在边界层的下部形成的。10 nm直径颗粒的形成速率估计为0.11 cm -3 s -1，生长速率在1 ~ 2 nm h -1之间。DOI: 10.1111 / j.1600-0889.2008.00412.x
{"title":"On small particles in the Arctic summer boundary layer : observations at two different heights near Ny-Alesund, Svalbard","authors":"J. Ström, Ann-Christine Engvall, F. Delbart, R. Krejci, R. Treffeisen","doi":"10.1111/J.1600-0889.2008.00412.X","DOIUrl":"https://doi.org/10.1111/J.1600-0889.2008.00412.X","url":null,"abstract":"Concurrent observations of particle number densities and size distributions observed at two different heights (near ocean level and 475 m above sea level) in Ny-Alesund, Svalbard were studied with respect to the diurnal variation during a summer period in June 2004. The results show that observed variation in particle number density in the Arctic boundary layer may be strongly modulated by vertical mixing and dilution. The particles appeared to be formed in the early morning when solar intensity reached about 30% of the mid-day intensity. Based on differences in the observed number densities at the two heights it appears as if particles are formed in the lower part of the boundary layer. The formation rate of 10 nm diameter particles is estimated to be 0.11 cm -3 s -1 and the growth rate is in a range between 1 and 2 nm h -1 . DOI: 10.1111/j.1600-0889.2008.00412.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2009-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75625251","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 : 2009-04-01DOI: 10.1111/J.1600-0889.2009.00415.X
A. Prenni, P. DeMott, D. Rogers, S. Kreidenweis, G. McFarquhar, Gong Zhang, M. Poellot
This paper presents airborne measurements of ice nuclei (IN) number concentration and elemental composition from the mixed-phase Arctic cloud experiment (M-PACE) in northern Alaska during October 2004. Although the project average IN concentration was low, less than 1 L -1 STP, there was significant spatial and temporal variability, with local maximum concentrations of nearly 60 L -1 STP. Immersion and/or condensation freezing appear to be the dominant freezing mechanisms, whereas mechanisms that occur below water saturation played a smaller role. The dominant particle types identified as IN were metal oxides/dust (39%), carbonaceous particles (35%) and mixtures of metal oxides/dust with either carbonaceous components or salts/sulphates (25%), although there was significant variability in elemental composition. Trajectory analysis suggests both local and remote sources, including biomass burning and volcanic ash. Seasonal variability of IN number concentrations based on this study and data from SHEBA/FIRE-ACE indicates that fall concentrations are depleted relative to spring by about a factor of five. Average IN number concentrations from both studies compare favorably with cloud ice number concentrations of cloud particles larger than 125 μ m, for temperatures less than −10 °C. Cloud ice number concentrations also were enhanced in spring, by a factor of ∼2, but only over a limited temperature range. DOI: 10.1111/j.1600-0889.2009.00415.x
本文介绍了2004年10月在阿拉斯加北部进行的混合相北极云实验(M-PACE)对冰核(IN)数、浓度和元素组成的航空测量结果。虽然项目平均IN浓度较低，小于1 L -1 STP，但存在显著的时空变异性，局部最高浓度接近60 L -1 STP。浸没和/或冷凝冻结似乎是主要的冻结机制，而发生在水饱和度以下的机制起较小的作用。被确定为氮氧化物的主要颗粒类型是金属氧化物/粉尘(39%)、碳质颗粒(35%)和金属氧化物/粉尘与碳质成分或盐/硫酸盐的混合物(25%)，尽管元素组成存在显著差异。轨迹分析表明有本地和远程来源，包括生物质燃烧和火山灰。基于本研究和SHEBA/FIRE-ACE数据的氮素数量浓度的季节变化表明，秋季浓度相对于春季减少了约五倍。在低于- 10°C的温度下，两项研究的平均IN数浓度与大于125 μ m的云粒子的云冰数浓度比较有利。云冰数浓度在春季也增加了约2倍，但仅在有限的温度范围内。DOI: 10.1111 / j.1600-0889.2009.00415.x
{"title":"Ice nuclei characteristics from M‐PACE and their relation to ice formation in clouds","authors":"A. Prenni, P. DeMott, D. Rogers, S. Kreidenweis, G. McFarquhar, Gong Zhang, M. Poellot","doi":"10.1111/J.1600-0889.2009.00415.X","DOIUrl":"https://doi.org/10.1111/J.1600-0889.2009.00415.X","url":null,"abstract":"This paper presents airborne measurements of ice nuclei (IN) number concentration and elemental composition from the mixed-phase Arctic cloud experiment (M-PACE) in northern Alaska during October 2004. Although the project average IN concentration was low, less than 1 L -1 STP, there was significant spatial and temporal variability, with local maximum concentrations of nearly 60 L -1 STP. Immersion and/or condensation freezing appear to be the dominant freezing mechanisms, whereas mechanisms that occur below water saturation played a smaller role. The dominant particle types identified as IN were metal oxides/dust (39%), carbonaceous particles (35%) and mixtures of metal oxides/dust with either carbonaceous components or salts/sulphates (25%), although there was significant variability in elemental composition. Trajectory analysis suggests both local and remote sources, including biomass burning and volcanic ash. Seasonal variability of IN number concentrations based on this study and data from SHEBA/FIRE-ACE indicates that fall concentrations are depleted relative to spring by about a factor of five. Average IN number concentrations from both studies compare favorably with cloud ice number concentrations of cloud particles larger than 125 μ m, for temperatures less than −10 °C. Cloud ice number concentrations also were enhanced in spring, by a factor of ∼2, but only over a limited temperature range. DOI: 10.1111/j.1600-0889.2009.00415.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2009-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88578926","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 : 2009-04-01DOI: 10.3402/TELLUSB.V61I2.16836
T. Naegler
Oceanic excess radiocarbon data is widely used as a constraint for air–sea gas exchange. However, recent estimates of the global mean piston velocity 〈 k 〉 from Naegler et al., Krakauer et al., Sweeney et al. and Muller et al. differ substantially despite the fact that they all are based on excess radiocarbon data from the GLODAP data base. Here I show that these estimates of 〈 k 〉 can be reconciled if first, the changing oceanic radiocarbon inventory due to net uptake of CO 2 is taken into account; second, if realistic reconstructions of sea surface Δ 14 C are used and third, if 〈 k 〉 is consistently reported with or without normalization to a Schmidt number of 660. These corrections applied, unnormalized estimates of 〈 k 〉 from these studies range between 15.1 and 18.2 cm h -1 . However, none of these estimates can be regarded as the only correct value for 〈 k 〉. I thus propose to use the ‘average’ of the corrected values of 〈 k 〉 presented here (16.5 ± 3.2 cm h -1 ) as the best available estimate of the global mean unnormalized piston velocity 〈 k 〉, resulting in a gross ocean-to-atmosphere CO 2 flux of 76 ± 15 PgC yr -1 for the mid-1990s. DOI: 10.1111/j.1600-0889.2008.00408.x
海洋过量放射性碳数据被广泛用作海气交换的约束条件。然而，Naegler等人、Krakauer等人、Sweeney等人和Muller等人最近对全球平均活塞速度< k >的估计存在很大差异，尽管他们都是基于GLODAP数据库中的过量放射性碳数据。这里我表明，如果首先考虑到二氧化碳净吸收引起的海洋放射性碳储量的变化，这些< k >估计值是可以调和的;第二，如果使用真实的海面重建Δ 14c，第三，如果< k >在施密特数660的归一化或不归一化的情况下一致地报告。这些校正应用，这些研究中< k >的非标准化估计范围在15.1和18.2 cm h -1之间。然而，这些估计都不能被视为< k >的唯一正确值。因此，我建议使用这里给出的< k >校正值的“平均值”(16.5±3.2 cm h -1)作为全球平均非标准化活塞速度< k >的最佳可用估计，从而得出20世纪90年代中期海洋到大气的CO 2总通量为76±15 PgC年-1。DOI: 10.1111 / j.1600-0889.2008.00408.x
{"title":"Reconciliation of excess 14 C-constrained global CO 2 piston velocity estimates","authors":"T. Naegler","doi":"10.3402/TELLUSB.V61I2.16836","DOIUrl":"https://doi.org/10.3402/TELLUSB.V61I2.16836","url":null,"abstract":"Oceanic excess radiocarbon data is widely used as a constraint for air–sea gas exchange. However, recent estimates of the global mean piston velocity 〈 k 〉 from Naegler et al., Krakauer et al., Sweeney et al. and Muller et al. differ substantially despite the fact that they all are based on excess radiocarbon data from the GLODAP data base. Here I show that these estimates of 〈 k 〉 can be reconciled if first, the changing oceanic radiocarbon inventory due to net uptake of CO 2 is taken into account; second, if realistic reconstructions of sea surface Δ 14 C are used and third, if 〈 k 〉 is consistently reported with or without normalization to a Schmidt number of 660. These corrections applied, unnormalized estimates of 〈 k 〉 from these studies range between 15.1 and 18.2 cm h -1 . However, none of these estimates can be regarded as the only correct value for 〈 k 〉. I thus propose to use the ‘average’ of the corrected values of 〈 k 〉 presented here (16.5 ± 3.2 cm h -1 ) as the best available estimate of the global mean unnormalized piston velocity 〈 k 〉, resulting in a gross ocean-to-atmosphere CO 2 flux of 76 ± 15 PgC yr -1 for the mid-1990s. DOI: 10.1111/j.1600-0889.2008.00408.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2009-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76104702","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 : 2009-04-01DOI: 10.1111/J.1600-0889.2008.00411.X
J. Salazar, G. Poveda
The role of a simplified hydrological cycle and a physical representation of clouds is investigated in the Daisyworld model, subject to constant and variable solar forcing and varying cloud albedo and height. Under constant forcing, properties of the cloudy hydrologic cycle control the long-term system dynamics to non-oscillatory, oscillatory, abiotic or biotic states. In case of oscillatory solutions, their amplitude and periodicity are controlled by the net cooling or warming effects from clouds. Two conditions are considered under variable forcing—active or neutral—depending on the existence or not of biota–environment feedbacks. Temperature, cloudiness and hydrological variables are self-regulated in the active condition, whereas non-regulated in the neutral condition. Self-regulation is quantified through two measurements (luminosity range and total life), both of which can be larger in our model than in several other variants of Daisyworld, depending on cloud characteristics. The hydrological cycle and clouds can make the planet more habitable for life, independent of the capacity of the system for biological adaptation. Two hypotheses are put forward: (1) beneficial effects for life emerge from biota–clouds interactions, enhancing the global amount of life and extending the life span; and (ii) the existence of a maximum self-regulation capacity principle. DOI: 10.1111/j.1600-0889.2008.00411.x
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Pub Date : 2008-09-01DOI: 10.3402/TELLUSB.V60I4.16937
H. Lejenäs, H. Rodhe
Professor emeritus Bert Bolin passed away on December 30, 2007 leaving a great blank behind him. He ecame the Editor-in-Chief of Tellus after the death of Carl-Gustaf Rossby in 1957. After the journal split into two series (A and B) in 1983 he remained as Editor-in-Chief of Tellus A until his retirement in 1990. DOI: 10.1111/j.1600-0889.2008.00362.x
{"title":"In Memoriam - Bert Bolin","authors":"H. Lejenäs, H. Rodhe","doi":"10.3402/TELLUSB.V60I4.16937","DOIUrl":"https://doi.org/10.3402/TELLUSB.V60I4.16937","url":null,"abstract":"Professor emeritus Bert Bolin passed away on December 30, 2007 leaving a great blank behind him. He ecame the Editor-in-Chief of Tellus after the death of Carl-Gustaf Rossby in 1957. After the journal split into two series (A and B) in 1983 he remained as Editor-in-Chief of Tellus A until his retirement in 1990. DOI: 10.1111/j.1600-0889.2008.00362.x","PeriodicalId":54432,"journal":{"name":"Tellus Series B-Chemical and Physical Meteorology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79488691","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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