Synthesis of observed air–sea CO<sub>2</sub> exchange fluxes in the river-dominated East China Sea and improved estimates of annual and seasonal net mean fluxes
Limited observations exist for a reliable assessment of annual CO<sub>2</sub> uptake that takes into consideration the strong seasonal variation in the river-dominated East China Sea (ECS). Here we explore seasonally representative CO<sub>2</sub> uptakes by the whole East Chi...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-07-01
|
| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/11/3855/2014/bg-11-3855-2014.pdf |
| _version_ | 1818957001998204928 |
|---|---|
| author | C.-M. Tseng P.-Y. Shen K.-K. Liu |
| author_facet | C.-M. Tseng P.-Y. Shen K.-K. Liu |
| author_sort | C.-M. Tseng |
| collection | DOAJ |
| description | Limited observations exist for a reliable assessment of annual CO<sub>2</sub> uptake
that takes into consideration the strong seasonal variation in the
river-dominated East China Sea (ECS). Here we explore seasonally
representative CO<sub>2</sub> uptakes by the whole East China Sea derived from
observations over a 14-year period. We firstly identified the biological
sequestration of CO<sub>2</sub> taking place in the highly productive,
nutrient-enriched Changjiang River plume, dictated by the Changjiang River
discharge in warm seasons. We have therefore established an
empirical algorithm as a function of sea surface temperature (SST) and
Changjiang River discharge (CRD) for predicting sea surface <i>p</i>CO<sub>2</sub>.
Syntheses based on both observations and models show that the annually
averaged CO<sub>2</sub> uptake from atmosphere during the period 1998–2011 was
constrained to about 1.8 ± 0.5 mol C m<sup>−2</sup> yr<sup>−1</sup>. This assessment
of annual CO<sub>2</sub> uptake is more reliable and representative, compared to
previous estimates, in terms of temporal and spatial coverage. Additionally,
the CO<sub>2</sub> time series, exhibiting distinct seasonal pattern, gives mean
fluxes of −3.7 ± 0.5, −1.1 ± 1.3, −0.3 ± 0.8 and
−2.5 ± 0.7 mol C m<sup>−2</sup> yr<sup>−1</sup> in spring,
summer, fall and winter, respectively, and also reveals apparent
interannual variations. The flux seasonality shows a strong sink in spring
and a weak source in late summer–mid-fall. The weak sink status during
warm periods in summer–fall is fairly sensitive to changes of <i>p</i>CO<sub>2</sub> and
may easily shift from a sink to a source altered by environmental changes
under climate change and anthropogenic forcing. |
| first_indexed | 2024-12-20T11:02:55Z |
| format | Article |
| id | doaj.art-afde9b3b0a3840b588ba54b4b85632cc |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-20T11:02:55Z |
| publishDate | 2014-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-afde9b3b0a3840b588ba54b4b85632cc2022-12-21T19:42:57ZengCopernicus PublicationsBiogeosciences1726-41701726-41892014-07-0111143855387010.5194/bg-11-3855-2014Synthesis of observed air–sea CO<sub>2</sub> exchange fluxes in the river-dominated East China Sea and improved estimates of annual and seasonal net mean fluxesC.-M. Tseng0P.-Y. Shen1K.-K. Liu2Institute of Oceanography, National Taiwan University, Taipei 106, TaiwanInstitute of Oceanography, National Taiwan University, Taipei 106, TaiwanInstitute of Hydrological & Oceanic Sciences, National Central University, Jungli, Taoyuan 320, TaiwanLimited observations exist for a reliable assessment of annual CO<sub>2</sub> uptake that takes into consideration the strong seasonal variation in the river-dominated East China Sea (ECS). Here we explore seasonally representative CO<sub>2</sub> uptakes by the whole East China Sea derived from observations over a 14-year period. We firstly identified the biological sequestration of CO<sub>2</sub> taking place in the highly productive, nutrient-enriched Changjiang River plume, dictated by the Changjiang River discharge in warm seasons. We have therefore established an empirical algorithm as a function of sea surface temperature (SST) and Changjiang River discharge (CRD) for predicting sea surface <i>p</i>CO<sub>2</sub>. Syntheses based on both observations and models show that the annually averaged CO<sub>2</sub> uptake from atmosphere during the period 1998–2011 was constrained to about 1.8 ± 0.5 mol C m<sup>−2</sup> yr<sup>−1</sup>. This assessment of annual CO<sub>2</sub> uptake is more reliable and representative, compared to previous estimates, in terms of temporal and spatial coverage. Additionally, the CO<sub>2</sub> time series, exhibiting distinct seasonal pattern, gives mean fluxes of −3.7 ± 0.5, −1.1 ± 1.3, −0.3 ± 0.8 and −2.5 ± 0.7 mol C m<sup>−2</sup> yr<sup>−1</sup> in spring, summer, fall and winter, respectively, and also reveals apparent interannual variations. The flux seasonality shows a strong sink in spring and a weak source in late summer–mid-fall. The weak sink status during warm periods in summer–fall is fairly sensitive to changes of <i>p</i>CO<sub>2</sub> and may easily shift from a sink to a source altered by environmental changes under climate change and anthropogenic forcing.http://www.biogeosciences.net/11/3855/2014/bg-11-3855-2014.pdf |
| spellingShingle | C.-M. Tseng P.-Y. Shen K.-K. Liu Synthesis of observed air–sea CO<sub>2</sub> exchange fluxes in the river-dominated East China Sea and improved estimates of annual and seasonal net mean fluxes Biogeosciences |
| title | Synthesis of observed air–sea CO<sub>2</sub> exchange fluxes in the river-dominated East China Sea and improved estimates of annual and seasonal net mean fluxes |
| title_full | Synthesis of observed air–sea CO<sub>2</sub> exchange fluxes in the river-dominated East China Sea and improved estimates of annual and seasonal net mean fluxes |
| title_fullStr | Synthesis of observed air–sea CO<sub>2</sub> exchange fluxes in the river-dominated East China Sea and improved estimates of annual and seasonal net mean fluxes |
| title_full_unstemmed | Synthesis of observed air–sea CO<sub>2</sub> exchange fluxes in the river-dominated East China Sea and improved estimates of annual and seasonal net mean fluxes |
| title_short | Synthesis of observed air–sea CO<sub>2</sub> exchange fluxes in the river-dominated East China Sea and improved estimates of annual and seasonal net mean fluxes |
| title_sort | synthesis of observed air sea co sub 2 sub exchange fluxes in the river dominated east china sea and improved estimates of annual and seasonal net mean fluxes |
| url | http://www.biogeosciences.net/11/3855/2014/bg-11-3855-2014.pdf |
| work_keys_str_mv | AT cmtseng synthesisofobservedairseacosub2subexchangefluxesintheriverdominatedeastchinaseaandimprovedestimatesofannualandseasonalnetmeanfluxes AT pyshen synthesisofobservedairseacosub2subexchangefluxesintheriverdominatedeastchinaseaandimprovedestimatesofannualandseasonalnetmeanfluxes AT kkliu synthesisofobservedairseacosub2subexchangefluxesintheriverdominatedeastchinaseaandimprovedestimatesofannualandseasonalnetmeanfluxes |