Satellite-derived surface water pCO2 and air–sea CO2 fluxes in the northern South China Sea in summer

Zhu, Yu; Shang, Shuo; Zhai, Weidong; Dai, Minhan

doi:10.1016/j.pnsc.2008.09.004

Cited by 52 publications

(39 citation statements)

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“…Many efforts have been made to estimate sea surface p CO 2 and air‐sea CO 2 fluxes from space by developing linear or multiple regression relationships between p CO 2 and satellite‐derived parameters, such as sea surface temperature (SST) [e.g., Stephens et al . ; Metzl et al ., ; Hood et al ., ; Nelson et al ., ; Levefre et al ., ; Cosca et al ., ; Olsen et al ., ; Lefèvre et al ., ] and/or chlorophyll a concentration ( chla ) [e.g., Ono et al ., ; Rangama et al ., ; Zhu et al ., ]. To obtain better regression equations leading to better predictions, more parameters, such as longitude, latitude [e.g., Wanninkhof et al ., ; Lueger et al ., ], salinity [e.g., Sarma et al ., ], colored dissolved organic matter (CDOM) [e.g., Lohrenz and Cai , ; Else et al ., ], and mixed layer depth [e.g., Lueger et al ., ], have been included.…”

Section: Introductionmentioning

confidence: 99%

A mechanistic semi‐analytical method for remotely sensing sea surface pCO₂ in river‐dominated coastal oceans: A case study from the East China Sea

et al. 2015

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While satellite remote sensing has become a very useful tool contributing to assessments of sea surface partial pressure of carbon dioxide (pCO 2 ) that subsequently allow quantification of air-sea CO 2 flux, the application of empirical approaches in coastal oceans has proven challenging owing to the interaction of multiple controlling factors. We propose a ''mechanistic semi-analytic algorithm'' (MeSAA) to estimate sea surface pCO 2 in river-dominated coastal oceans using satellite data. Observed pCO 2 can be analytically expressed as the sum of individual components controlled by major factors such as thermodynamics (or temperature), mixing, and biology. With marine carbonate system calculations, temperature and mixing effects can be predicted using thermodynamic principles and by assuming conservative two endmember mixing of total dissolved inorganic carbon and total alkalinity (e.g., the Changjiang River and Kuroshio water in the East China Sea, ECS). Next, an integral expression for pCO 2 drawdown due to biological effects can be parameterized using the chlorophyll a concentration (chla). We demonstrate the validity and applicability of the algorithm in the ECS during summertime. Sensitivity analysis shows that errors in empirical coefficients and three input satellite parameters (salinity, SST, chla) have limited influence on the algorithm, and satellite-derived pCO 2 is consistent with underway data, even though no in situ pCO 2 data from the ECS shelves was used to train the algorithm. Our algorithm has more physical and biogeochemical mechanistic meaning than empirical methods, and should be applicable to other similar systems.

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Section: Introductionmentioning

confidence: 99%

A mechanistic semi‐analytical method for remotely sensing sea surface pCO₂ in river‐dominated coastal oceans: A case study from the East China Sea

et al. 2015

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“…Empirical relations have been developed between satellitederived sea surface temperatures (SST) and pCO 2 in water (pCO 2water , measured in situ) (Zirino et al 1997, Boutin et al 1999; between chlorophyll a concentrations and pCO 2water (Zhu et al 2009); or between pCO 2water , chlorophyll a concentrations, and SST (Chen et al 2011). Some authors have used a combination of these methods, such as empirical relations and the compilation of available data from oceanographic cruises (Wanninkhof et al 2012).…”

Section: Introductionmentioning

confidence: 99%

“…Asimismo, se han desarrollado relaciones empíricas entre la temperatura superficial del mar (TSM) medida con imágenes de satélite y la pCO 2 del agua (pCO 2agua , medida in situ) (Zirino et al 1997, Boutin et al 1999, o entre la concentración de clorofila a y la pCO 2agua (Zhu et al 2009). Otros autores han desarrollado relaciones empíricas entre la pCO 2agua , la concentración de clorofila a y la TSM (Chen et al 2011), o bien, la combinación de estas metodologías como las relaciones empíricas y la recopilación de datos disponibles de cruceros oceanográficos (Wanninkhof et al 2012).…”

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Water–air carbon fluxes in the coastal upwelling zone off northern Baja California

et al. 2015

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M C INTRODUCTIONA topic of great concern and interest for climatologists and oceanographers is to determine how quickly natural and anthropogenic CO 2 is being absorbed by the oceans. The ocean acts as a large CO 2 sink (Takahashi et al. 2009), and a better understanding of the actual rate of ocean uptake of INTRODUCCIÓNUno de los temas más críticos y de gran interés para climatólogos y oceanólogos es conocer qué tan rápido está siendo absorbido el CO 2 natural y antropogénico por el océano. Dado que el océano es un gran sumidero de CO 2 (Takahashi et al. 2009) ABSTRACT. An important challenge in marine science is to quantify the air-sea flux of carbon because of its possible relation to climate change and the decreasing pH in seawater. In coastal areas of Mexico, the magnitude and variability of carbon fluxes between the ocean and the atmosphere is almost completely unknown. Therefore, the objective of this research was to determine the variability of air-sea carbon fluxes in the upwelling system off northern Baja California. A one-year time series of carbon fluxes was generated from data on partial pressure of carbon dioxide (pCO 2 ) from an oceanographic buoy installed immediately south of Punta Banda (Ensenada, Baja California), which measured salinity, temperature, and pCO 2 in the water (pCO 2water ) and air (pCO 2air ) every 3 h during 2009. The study area presented several upwelling events with low sea surface temperatures (≤14 ºC), salinity <34.0, and high values of pCO 2water , which resulted in an export of excess CO 2 in the water to the atmosphere, identifying the area as a temporary source of CO 2 . In contrast, during the relaxation of upwelling, low values of pCO 2water and intermediate surface temperatures resulted in the sea acting as a sink for CO 2 . The average daily flux was 0.6 ± 0.11 mmol C m ; thus, the system turned out to be a net source of CO 2 from the ocean to the atmosphere.Key words: ocean-atmosphere carbon fluxes, coastal zone, upwelling, North Pacific. RESUMEN.Cuantificar los flujos mar-atmósfera de carbono es un reto ambiental importante por su posible relación con el cambio climático y la disminución del pH del mar. En las zonas costeras de México se desconoce casi totalmente la magnitud y la variabilidad de los flujos de carbono entre el océano y la atmósfera. Por tal motivo, el objetivo de esta investigación fue conocer la variabilidad de los flujos de carbono en el sistema de surgencias frente a Baja California norte. Los flujos de carbono se estimaron de una serie de tiempo de la presión parcial de bióxido de carbono (pCO 2 ) generada a través de una boya oceanográfica instalada inmediatamente al sur de punta Banda, (Ensenada, Baja California), la cual medía salinidad, temperatura y pCO 2 en el agua (pCO 2agua ) y el aire (pCO 2aire ), cada 3 h durante 2009. La zona de estudio presentó varios eventos de surgencias, con temperaturas superficiales del mar bajas (≤14 ºC), salinidad <34.0 y valores altos de pCO 2agua , cuyo resultado fue una exportación del exceso de CO 2 en e...

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“…Remote sensing pCO 2 data are used to calculate the spatial variability and the correlation among observations in individual grid boxes. Given the rapidly growing applications of remote sensing techniques in mapping pCO 2 and constraining pCO 2 spatial variability [e.g., Stephens et al, 1995;Nelson et al, 2001;Ono et al, 2004;Sarma et al, 2006;Zhu et al, 2009;Hales et al, 2012;Jo et al, 2012], our approach to estimating uncertainty in gridded pCO 2 data should have numerous applications.…”

Section: Introductionmentioning

confidence: 99%

Quantifying uncertainty sources in the gridded data of sea surface CO₂ partial pressure

et al. 2014

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The bulk uncertainty in the gridded sea surface pCO 2 data is crucial in assessing the reliability of the CO 2 flux estimated from measurements of air-sea pCO 2 difference, because atmospheric pCO 2 are relatively homogeneous and well defined. The bulk uncertainty results from three different sources: analytical error (E m ), spatial variance (r 2 s ), and the bias from undersampling (r 2 u ). Common uncertainty quantification by standard deviation may mix up the different sources of uncertainty. We have established a simple procedure to determine these three sources of uncertainty using remote sensing-derived and field-measured pCO 2 data. E m is constrained by the analytical method and data reduction procedures. r 2 s is derived from the remotely sensed pCO 2 field. r 2 u is determined by spatial variance and the effective number of observations, considering, for the first time, the geometric bias introduced by pCO 2 sampling. This approach is applied to 1 3 1 gridded pCO 2 data collected from the East China Sea. We demonstrate that the spatial distribution of these biases is uneven and that none of them follow the same spatial trend as the standard deviation. r 2 s contributes the most to the uncertainty in gridded pCO 2 data over those grid boxes with good sampling coverage, while r 2 u dominates the total uncertainty in the grid boxes with poor sampling coverage. Application of this procedure to other parts of the global ocean will help to better define the inherent spatial variability of the pCO 2 field and thus better interpolate and/or extrapolate pCO 2 data, and eventually better constrain air-sea CO 2 fluxes.

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Satellite-derived surface water pCO2 and air–sea CO2 fluxes in the northern South China Sea in summer

Cited by 52 publications

References 10 publications

A mechanistic semi‐analytical method for remotely sensing sea surface pCO₂ in river‐dominated coastal oceans: A case study from the East China Sea

A mechanistic semi‐analytical method for remotely sensing sea surface pCO₂ in river‐dominated coastal oceans: A case study from the East China Sea

Water–air carbon fluxes in the coastal upwelling zone off northern Baja California

Quantifying uncertainty sources in the gridded data of sea surface CO₂ partial pressure

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Satellite-derived surface water pCO2 and air–sea CO2 fluxes in the northern South China Sea in summer

Cited by 52 publications

References 10 publications

A mechanistic semi‐analytical method for remotely sensing sea surface pCO2 in river‐dominated coastal oceans: A case study from the East China Sea

A mechanistic semi‐analytical method for remotely sensing sea surface pCO2 in river‐dominated coastal oceans: A case study from the East China Sea

Water–air carbon fluxes in the coastal upwelling zone off northern Baja California

Quantifying uncertainty sources in the gridded data of sea surface CO2 partial pressure

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A mechanistic semi‐analytical method for remotely sensing sea surface pCO₂ in river‐dominated coastal oceans: A case study from the East China Sea

A mechanistic semi‐analytical method for remotely sensing sea surface pCO₂ in river‐dominated coastal oceans: A case study from the East China Sea

Quantifying uncertainty sources in the gridded data of sea surface CO₂ partial pressure