{"title":"Reconciliation of excess 14 C-constrained global CO 2 piston velocity estimates","authors":"T. Naegler","doi":"10.3402/TELLUSB.V61I2.16836","DOIUrl":null,"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":2.3000,"publicationDate":"2009-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"37","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Tellus Series B-Chemical and Physical Meteorology","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.3402/TELLUSB.V61I2.16836","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"METEOROLOGY & ATMOSPHERIC SCIENCES","Score":null,"Total":0}
引用次数: 37
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
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
期刊介绍:
Tellus B: Chemical and Physical Meteorology along with its sister journal Tellus A: Dynamic Meteorology and Oceanography, are the international, peer-reviewed journals of the International Meteorological Institute in Stockholm, an independent non-for-profit body integrated into the Department of Meteorology at the Faculty of Sciences of Stockholm University, Sweden. Aiming to promote the exchange of knowledge about meteorology from across a range of scientific sub-disciplines, the two journals serve an international community of researchers, policy makers, managers, media and the general public.