Dissertationen zum Thema „CO2 Air-Sea fluxes“
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Bianchi, Alejandro. „Sea-air CO2 fluxes in the Patagonia sea“. Paris 6, 2010. http://www.theses.fr/2010PA066613.
Der volle Inhalt der QuelleNorman, Maria. „Air-Sea Fluxes of CO2 : Analysis Methods and Impact on Carbon Budget“. Doctoral thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-194960.
Der volle Inhalt der QuelleWittskog, Cristoffer. „Carbon dioxide in the atmosphere: A study of mean levels andair-sea fluxes over the Baltic Sea“. Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-303863.
Der volle Inhalt der QuelleKoldioxid(CO2)-koncentrationen i atmosfären har ökat stadigt sen början av industrialiseringen. Effekten som de ökade CO2-halterna kommer ha på framtidens klimat är ännu inte helt utrett. CO2 bidrar till den livsviktiga växthuseffekten. Det är en ökning av växthusgaser, bland annat CO2, som leder till en ökning av växthuseffekten. Ökad växthuseffekt leder till högre temperatur på jorden. Den största ökningen av CO2 i atmosfären beror på förbränning av fossila bränslen. Även förändringen i markanvändning leder till ökade halter av CO2. De största sänkorna av CO2 är den organiska konsumtionen av CO2 och havens upptag av CO2. Den organiska konsumtionen av CO2 varierar mycket under året och är som störst under de varmare månaderna. Havens upptag av CO2 varierar också mycket under året eftersom havens förmåga att lösa CO2 beror på vattnets temperatur. Syftet med den här studien är att analysera CO2-koncentrationen och CO2-flödena mellan hav och luft på Östergarnsholm, en liten, låg ö öster om Gotland. Resultaten jämförs med tidigare studier. CO2-koncentrationsdata samlades in mellan 1997 – 1999 och 2001 – 2003. CO2-flödesdata samlades in mellan 2001 och 2003. Analysen av CO2-koncentrationen visar att under perioden 1997 till 1999 är CO2- halterna för låga på Östergarnsholm. En korrektion gjordes genom att lägga till 27 ppm till de uppmätta CO2-halterna. Årsvariationerna av CO2-halterna är mycket tydliga men sommaren 1998 sjunker inte CO2-halten till så låga värden som de borde vara. Att CO2-halterna inte sjönk mer beror dels på El Niño-utbrottet 97/98 och dels på den lokalt kalla och regniga sommaren. De direkt mätta CO2-flödena korrigerades med hjälp av den välkända Webbkorrektionen innan de analyserades. CO2-flödena är beroende av vindhastigheten – högre vindhastighet ger högre CO2-flöden. CO2-flödena beror också på skillnaden i CO2-halt mellan luften och havet. Parameteriserade CO2-flöden beräknades och jämfördes med de direkt mätta CO2-flödena. De parameteriserade CO2-flödena beräknas antingen med kvadratiskt eller kubiskt vindberoende. För att beräkna parameteriserade CO2-flöden användes ett fast värde på skillnaden i CO2-halt mellan luften och vattnet eftersom CO2-halten i vattnet inte mäts. De parameteriserade CO2- flödenas vindberoende stämde överrens med de direkt mätta CO2-flödena.
Marrec, Pierre. „Dynamics of the carbonate system and air-sea CO2 fluxes in western European shelf waters : a multi-scale approach“. Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066656/document.
Der volle Inhalt der QuelleThe raise of atmospheric CO2 due to anthropogenic activities is a major driver of the climate change. The ocean plays a key role in the uptake of this anthropogenic CO2. The constraint of air–sea CO2 fluxes and their variability at various time and spatial levels remain a central task in global carbon cycle and climate studies. The contribution of open ocean to this uptake is presently rather well quantified, whereas the role of the coastal ocean to this process remains ambiguous due to the diversity and the high spatio-temporal variability of the CO2 system and air-sea CO2 fluxes in these ecosystems. This PhD thesis investigated the spatial and temporal variability of the CO2 system and air-sea CO2 fluxes in contrasted ecosystems of the north-west European continental shelf. These highly dynamic biogeochemical ecosystems host numerous key hydrographical structures (permanently well-mixed, seasonally stratified, frontal structures, estuarine) of temperate zones, in which the dynamic of the CO2 system were poorly documented. From tidal to multi-annual variability, from a fixed station off Roscoff to the north-west European continental shelf and from seawater samples to satellite data, this PhD thesis provides an integrative overview of the complexity of the CO2 system dynamics in coastal seas and the ongoing challenges to achieve
Marrec, Pierre. „Dynamics of the carbonate system and air-sea CO2 fluxes in western European shelf waters : a multi-scale approach“. Electronic Thesis or Diss., Paris 6, 2014. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2014PA066656.pdf.
Der volle Inhalt der QuelleThe raise of atmospheric CO2 due to anthropogenic activities is a major driver of the climate change. The ocean plays a key role in the uptake of this anthropogenic CO2. The constraint of air–sea CO2 fluxes and their variability at various time and spatial levels remain a central task in global carbon cycle and climate studies. The contribution of open ocean to this uptake is presently rather well quantified, whereas the role of the coastal ocean to this process remains ambiguous due to the diversity and the high spatio-temporal variability of the CO2 system and air-sea CO2 fluxes in these ecosystems. This PhD thesis investigated the spatial and temporal variability of the CO2 system and air-sea CO2 fluxes in contrasted ecosystems of the north-west European continental shelf. These highly dynamic biogeochemical ecosystems host numerous key hydrographical structures (permanently well-mixed, seasonally stratified, frontal structures, estuarine) of temperate zones, in which the dynamic of the CO2 system were poorly documented. From tidal to multi-annual variability, from a fixed station off Roscoff to the north-west European continental shelf and from seawater samples to satellite data, this PhD thesis provides an integrative overview of the complexity of the CO2 system dynamics in coastal seas and the ongoing challenges to achieve
Dufour, Carolina. „Rôle des tourbillons océaniques dans la variabilité récente des flux air-mer de CO2 dans l'océan Austral“. Thesis, Grenoble, 2011. http://www.theses.fr/2011GRENU040/document.
Der volle Inhalt der QuelleBy taking up large amounts of atmospheric CO2, the Southern Ocean helps to regulate the climate system. Southern Ocean carbon sink is poorly constrained, in part because data coverage is sparse and also because ocean models that have been used in such assessments fail to explicitly resolve key physical features such as mesoscale eddies. In recent decades, the growth of the Southern Ocean carbon sink may have been partly counteracted due to a loss of natural CO2 from the ocean driven by an intensification of westerlies, related to a positive trend in the Southern Annular Mode (SAM). This thesis focuses on documenting and understanding recent spatial and temporal variability of air-sea CO2 fluxes in the Southern Ocean. Sensitivity to positive phases of the SAM are tested by making simulations with a regional model of the Southern Ocean (south of 30°S) that couples biogeochemistry to the dynamics, is forced by atmosphere reanalysis data, and partially resolves the mesoscale. The resulting response of Southern Ocean CO2 fluxes to the SAM is dominated by a strong CO2 efflux to the atmosphere from the Antarctic Zone due to an increase in surface dissolved inorganic carbon (DIC). This increase is driven by the mixed-layer dynamics and is supplied by a meridional transport of DIC, a competition between the wind-driven circulation and the standing eddy-induced circulation. This work discusses the effect of increasing model resolution on simulated air-sea CO2 fluxes
Olivier, Léa. „Rôle de la mésoéchelle dans l'océan Atlantique tropical sur la salinité et les flux air-mer de CO2“. Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS149.
Der volle Inhalt der QuelleThe tropical Atlantic Ocean (TAO) controls exchanges from one hemisphere to the other and is a place of strong interactions with the atmosphere. The TAO is home to five of the world's largest rivers as well as intense rainfall in the intertropical convergence zone (ITCZ). This induces large spatial variability of salinity and of air-sea CO2 flux. While the global ocean is a strong CO2 sink, the TAO is a strong source of CO2 to the atmosphere due to the deep waters rich in inorganic carbon upwelled to the surface at the equator. However, this source is mitigated by the low CO2 concentrations in the Amazon River plume whose freshwater is low in inorganic carbon and favours phytoplankton blooms. It is in this context that propagate the tropical instability waves (TIWs) and the North Brazil current (NBC) rings, the two dominant mesoscale forms in the TAO. The objective of this work is to describe and understand the variability of the surface salinity and CO2 fluxes associated with the mesoscale. In-situ observations collected during cruises and Argo floats are coupled to surface satellite salinity, temperature and chlorophyll-a. In the equatorial Atlantic the salinity gradient between the fresh water from rainfall under the ITCZ and the salty water of the equatorial upwelling is very strong in May-June. The TIWs strongly distort this gradient, and are therefore particularly well observed in surface salinity. The observation of TIWs in salinity provides complementary information to their observation in surface temperature on their seasonal and interannual variability. Furthermore, salinity does not only play the role of a passive tracer, as together with temperature, it determines the seawater surface density. This affects the energy that allows TIWs to develop and propagate. One of the energy sources is the potential energy generated by the deformation of the density gradient. The effect of salinity on this energy is as strong as that of temperature, which means that by adding the contribution of salinity, the potential energy is doubled. TIWs modify and are modified by the salinity in the equatorial Atlantic. On the western edge of the basin, the Amazon plume results in even more salinity variability than in the equatorial Atlantic. The NBC rings, eddies that are 200 km in diameter, are highly contrasted structures. They trap the salty, CO2-rich waters of the NBC, but their rotation stirs water from the Amazon plume. The fresh water of the plume enhances the exchanges of CO2 and heat with the atmosphere. The northwestern TA in February 2020 was found to be a CO2 sink 10 times stronger than expected, and more than 40% of this flux is due to the effect of eddies. Their role is twofold, on the one hand they stir the plume which becomes a strong carbon sink, but also, they do not retain the CO2-rich surface signature of the waters they trap, and instead often stir freshwater filaments. The situation in summer is very different from the one in winter. The NBC changes its orientation by 90° and instead of following the South American coastline, it flows towards Africa. The NBC passes the mouth of the Amazon that is close to its maximum discharge and advects the plume eastwards. However, the NBC rings and the winds change this classical pattern. The formation and propagation of eddies make the plume discontinuous, and the winds favour a northwestward transport of fresh water. Thus, in August -September, whereas part of the plume indeed flows eastwards, another part is advected towards the Lesser Antilles. Particularly strong examples of this were observed in late summer 2021. This work shows the importance of the oceanic mesoscale for understanding key phenomena, such as the propagation of the TIWs and of the Amazon plume and the TAO carbon budget
Prytherch, John. „Measurement and parameterisation of the air-sea CO2 flux in high winds“. Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/209567/.
Der volle Inhalt der QuelleGutiérrez-Loza, Lucía. „Mechanisms controlling air-sea gas exchange in the Baltic Sea“. Licentiate thesis, Uppsala universitet, Luft-, vatten- och landskapslära, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-409744.
Der volle Inhalt der QuelleAndersson, Andreas. „Air-sea exchange of O2 and CO2 : Processes controlling the transfer efficiency“. Doctoral thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-314166.
Der volle Inhalt der QuelleMongwe, Ndunisani Precious. „Understanding modelled sea-air CO2 flux biases in the Southern Ocean through the seasonal cycle“. Doctoral thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29260.
Der volle Inhalt der QuelleRoobaert, Alizée. „Observation-based estimates of the global oceanic CO2 sink: Spatiotemporal analysis, quantification of uncertainties, processes description“. Doctoral thesis, Universite Libre de Bruxelles, 2020. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/307139.
Der volle Inhalt der QuelleDepuis le début de la révolution industrielle, une grande quantité de gaz à effet de serre tels que le dioxyde de carbone (CO2) a été émise dans l'atmosphère en raison des activités humaines. L'une des principales conséquences de ces émissions est une augmentation rapide de la concentration en CO2 atmosphérique et une modification profonde du système climatique de la Terre. L'océan joue un rôle important dans l'équilibre radiatif de la Terre car il agit comme un important puits de CO2 pour l'atmosphère. En absorbant actuellement environ 25 % du CO2 émis par l'homme, il ralentit considérablement le changement climatique. Comprendre la dynamique spatiale et temporelle actuelle de l'échange de CO2 air-mer et les différents processus qui régissent cet échange est d'une importance cruciale pour anticiper l'évolution du puits océanique de CO2 à l'avenir.Cette thèse a été réalisée dans ce contexte et s'est concentrée sur une meilleure quantification de l'échange de CO2 à travers l'interface air-mer (FCO2) de l'océan global, considérant à la fois l’océan ouvert et les régions côtières. L'objectif principal était de combler les lacunes dans notre compréhension des processus qui régissent la distribution spatiale et temporelle du FCO2. Cet objectif a été principalement atteint grâce à des approches observationnelles et a abordé trois aspects principaux: une quantification des différentes sources d'incertitudes du FCO2 à l'échelle globale, une analyse de la distribution spatiale de l'échange de CO2 océanique avec un fort accent sur l'océan côtier et une première évaluation de la dynamique saisonnière du FCO2 côtier et de ses moteurs sous-jacents. Ce dernier s'est appuyé sur une approche de fusion de modèles et d’approches observationnelles permettant de décomposer la saisonnalité du FCO2 en ses principaux moteurs physiques et biogéochimiques.La quantification du FCO2 océanique à partir d’observations consiste à calculer un gradient de pression partielle air-mer de CO2 (ΔpCO2) entre l'atmosphère et la surface de la mer. Des produits globaux continus mensuels de la pression partielle de CO2 (pCO2) peuvent par exemple être dérivés à partir de bases de données observationnelles de pCO2 et de méthodes d'interpolation statistique. ΔpCO2 est ensuite multiplié par un coefficient de vitesse de transfert d'échange gazeux (k), qui dépend de la vitesse du vent. Cependant, la paramétrisation de k est sujette à de larges incertitudes et mal quantifiées. À partir d'une synthèse de la littérature de toutes les paramétrisations de k disponibles dans la littérature au cours des 25 dernières années, j'ai d'abord quantifié les incertitudes sur FCO2 associées à k à l'échelle globale et régionale pour l'océan ouvert. J'ai également quantifié les incertitudes associées au choix d'un produit éolien par rapport à un autre. Nos résultats montrent que la gamme du FCO2 global, calculée avec ces différentes paramétrisations de k, diverge de 12 % lors de l'utilisation de CCMP, ERA ou NCEP1. En raison des différences dans les pattern de vent régionaux, les différences régionales sur le FCO2 sont plus prononcés que globalement. Ces différences globales et régionales augmentent de manière significative lors de l'utilisation de NCEP2 ou d'autres formulations de k. Afin de réduire les incertitudes associées au choix du produit de vent, il est possible de recalculer la paramétrisation de k pour un produit de vent donné et à une résolution spatio temporelle.Dans un deuxième temps, nous avons amélioré la quantification et l'analyse des principaux pattern et des différents processus sur la distribution spatiale du FCO2 pour l’ensemble des régions côtières. Cette analyse a été réalisée à l'échelle globale (à une résolution spatiale de 0.25°), en utilisant une segmentation régionale de l'océan côtier, et latitudinalement. J'ai trouvé que les régions côtières aux hautes latitudes agissent comme un puits de CO2 tandis que les régions côtières tropicales et le long de l'équateur ont tendance à agir comme une source de CO2 atmosphérique. Globalement, j'ai quantifié que les régions côtières agissent actuellement en tant que puits de CO2 avec une valeur de -0.20 ± 0.02 Pg C an-1. Pour la première fois, j'ai également comparé la distribution spatiale du FCO2 côtier à celle de l'océan ouvert adjacent, à l'échelle globale. À l'exception de certaines régions telles que celles dominées par les apports fluviaux, j'ai démontré que les régions côtières et l’océan ouvert adjacent présentaient une distribution latitudinale similaire sur leur densité de FCO2 par unité de surface, suggérant des réponses analogues à l'augmentation du CO2 atmosphérique. J'ai également réévalué le budget mondial de CO2 de l'océan et estimé une absorption mondiale de CO2 anthropique comprise entre -2.6 ± 0.4 Pg C an-1 et -2.9 ± 0.5 Pg C an-1 pour la période 1998-2015. Dans un troisième temps, j'ai contribué à la création du premier produit continu de pCO2 observationnelles fusionnant le domaine côtier et l'océan ouvert de manière cohérente. Cette étude a montré que la différence entre les estimations provenant du produit de pCO2 de l’océan ouvert à celles dérivant du produit de pCO2 de l’océan côtier le long de leur zone de chevauchement augmente avec la latitude mais reste proche de 0 µatm globallement. Des divergences plus fortes existent cependant au niveau régional, entraînant des différences qui dépassent 10 % sur la moyenne climatologique de pCO2, en particulier dans les régions contraintes par moins d'observations, associées à une complexité biogéochimique, comme le système d'upwelling péruvien et les régions couvertes de glace.Dans une quatrième étape, une analyse temporelle de la saisonnalité du FCO2 a été réalisée pour l'océan côtier sur la base d'une approche observationnelle. J'ai analysé et quantifié la dynamique saisonnière du FCO2 à l'échelle globale et pour différentes bandes latitudinales. À l'échelle globale, les régions côtières agissent comme un puits de CO2 avec une absorption plus intense se produisant en été (-21 Tg C mois-1) en raison de l'influence disproportionnée des régions côtières des hautes latitudes dans l'hémisphère Nord. J'ai également estimé la contribution de différents processus (couverture de glace de mer, vitesse du vent et changement de ΔpCO2) à l'amplitude saisonnière du FCO2. Cette approche basée sur les données observationnelles m'a permis de conclure que ΔpCO2 est le principal moteur de la variabilité du FCO2 à l'échelle saisonnière. J'ai ensuite utilisé un modèle biogéochimique océanique global pour décomposer davantage la variabilité saisonnière du pCO2 côtier en ses processus physiques et biologiques. À partir d'une première évaluation qualitative, j'ai conclu que l'effet thermique associé aux changements de température de la surface de la mer est le principal effet régissant la variabilité côtière saisonnière du pCO2 sauf aux hautes latitudes où l'effet non thermique associé aux changements de biologie, de circulation, d'eau douce et de l’échange de CO2 air-mer domine. J'ai également constaté que, globalement, l'effet thermique à lui seul devrait entraîner des fluctuations saisonnières plus importantes, mais son influence est en partie compensée par l'effet non thermique.Tout au long de cette thèse, j'ai également évalué dans quelle mesure les produits continus de pCO2 observationnelles dérivés d'une approche de réseau de neurones artificiels et du modèle biogéochimique océanique global MOM6-COBALT pourraient reproduire les champs de pCO2 bruts extraits des bases de données globale. Dans l'ensemble, j'ai montré qu'à l'échelle régionale, les deux produits sont relativement en bon accord par rapport aux observations. J'ai également identifié les régions où les différences sont les plus importantes et où de futures données observationnelles sont nécessaires à l'avenir, ainsi que les régions où les deux produits présentent un accord le plus satisfaisant et, par conséquent, le plus approprié pour de futures analyses de compréhension des différents processus.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Villela, Franco Nadal Junqueira. „Análise decadal do fluxo de CO2 entre o oceano e a atmostera na Passagem de Drake, Oceano Austral“. Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/90/90131/tde-24112011-125748/.
Der volle Inhalt der QuelleVILLELA, FRANCO N. J. Decadal analysis of the CO2 sea-air flux in the Drake Passage, Southern Ocean 2011. 148 f. Dissertação (mestrado) Programa de Pós-Graduação em Ciência Ambiental (PROCAM), Universidade de São Paulo, São Paulo, 2011. For the area bounded by parallels 60°S and 62.5°S and meridians 60°W and 65°W, located in the southern Drake Passage in the Southern Ocean, near the Antarctic Peninsula, mean seasonal and annual distributions of CO2 flux at the ocean-atmosphere interface, from 2000 to 2009, have been computed, as well as their associated variables: the CO2 partial pressure at sea surface (PCO2sw), the CO2 partial pressure in atmosphere (PCO2ar), the CO2 pressure difference between ocean and atmosphere (PCO2), and the gas transfer rate (TR), which is the product of the CO2 solubility coefficient in sea water by the gas transfer velocity. The parameterization used to calculate fluxes was that of Takahashi et al. (2009) with TR depending on the squared wind speed multiplied by a scale factor 0.26. The study area has about 75,000 km2 and was divided into a grid of 0.5° x 0.5°, resulting in 50 area boxes. Over 46,000 PCO2sw measurements were used, which in the spatial mean varied from 362.7±11.2 to 371.9±17.5 µatm, in summer and spring, respectively. The PCO2 varied from 0.4 to 5.7 µatm in autumn and spring, respectively. TR varied from 0.065±0.04 to 0,088±0.002 gC.month-1.m-2.µatm-1, in summer and winter, respectively. The net flux, taking ice concentration as negligible, varied from 0.039±0.865 to 0.456±1.221 gC.month-1.m-2, in autumn and winter, respectively. The total annual carbon flux, estimated through the spatial mean per square, was 95 GgC.y-1. Thus, in the annual estimate the region acts as a source to the atmosphere, mainly due to the continental shelf having PCO2sw considerably greater than that of the atmosphere. Seasonally, it is suggested that in summer the greater availability of solar radiation, warmer sea surface temperature (SST), and weaker winds favor the production of phytoplanktonic mass, making the biological pump the dominating process in lowering the PCO2sw and the absorption of atmospheric CO2 by the sea surface. On the other hand, in winter winds intensify and, in association with the strong cooling of the SST, promote mixing with deep waters rich in dissolved inorganic carbon, leading the sea surface to a state of supersaturation in CO2 relative to the atmosphere. Stronger circumpolar west winds and displaced to the south have been pointed as the cause for the increase of PCO2sw at a rate equal to or greater than that occurring in the atmosphere. In the study area it has been detected a mean trend of wind intensity 0.23±0.03 m.s-1.decade-1 and an increase in the western zonal component of 1.47±1.3%.decade-1. It is suggested that these trends are related to the Southern Annular Mode (SAM). However, the decadal trend estimated for the PCO2sw was smaller than for the atmosphere, in spite of both indicating increasing tendencies. It is believed that the great variability and scatter distribution of the data have masked the magnitude of the PCO2SW trend estimate.
Chang, Yung-Tsang, und 張詠翔. „Comparison of CO2 fluxes determining with the eddy covariance system and the CO2 partial pressure gradient between the air-sea interfaces“. Thesis, 2011. http://ndltd.ncl.edu.tw/handle/69230859096246131819.
Der volle Inhalt der Quelle中興大學
環境工程學系所
99
Open path CO2 analyzer has been used in CO2 flux measurements over ocean recently. CO2 flux has been estimated by close path CO2 analyzer for decades. To compare the CO2 flux of open path and close path methods, three experiments were set in the study: (1) using open path eddy covariance system (ECS) and close path Underway pCO2 system to measure CO2 fluxes over pool in Black-faced Spoonbill Conservation Association in Cigu Dist. The results showed that the CO2 flux of open path CO2 analyzer is up to 100 times larger than that of close path, but the direction of flux is opposite; (2) in the second case, the third method, profile method was added to estimate CO2 flux. The result of profile method showed that the tendency of flux is the same as ECS, but the flux of profile method is about 8 times larger than open path, however, direction of flux was still inconsistent with Underway pCO2 system; (3) the results of the experiment in a fish pond which has stronger ecosphere activities showed that the flux of open path is positive (sink), and it’s negative (source) for close path method. In addition, the diurnal cycle of CO2 concentration is obvious where it is lower in the daytime and higher at night. The PKT Method was used to calibrate the effect between relative humidity and CO2 concentration in case (1) and case (3). In both cases, PKT Method can correct the biases resulted from the relative humidity after WPL correction, the CO2 flux after calibrating by PKT Method was smaller than WPL calibration method, and the flux in May 14th is similar to the flux of Underway pCO2 system, but the direction of flux is still opposite. After adding pH parameter and CO2 atmospheric concentration measured at 1.5 m into the CO2 flux calculation of Underway pCO2 system, the results showed that the flux and the direction of flux will be consistent with ECS.
Luo, Zhi-Yu, und 羅智譽. „Effect of wind regarding reliability and variability on the flux estimates of the air-sea CO2 exchange in the East China Sea“. Thesis, 2014. http://ndltd.ncl.edu.tw/handle/94896553266910480931.
Der volle Inhalt der Quelle國立臺灣大學
海洋研究所
102
To accurately investigate air-sea CO2 exchange in the coastal waters, especially for the East China Sea (ECS), is challenging because of the environment complexities and diversity of the shelf seas, easily affected by human activities and climate changes. Reliable assessments of air-sea CO2 exchange fluxes in the ECS are additionally limited by inadequately spatiotemporal coverage and shortage of manpower resources. Here, we explore seasonally representative CO2 uptakes by the whole ECS by combining the remote sensing data and field observations. We firstly evaluated the results of Tseng et al. (2014) and further demonstrated the reliability and representativeness of Tseng’s empirical algorithm for computing pCO2 by using remote sensing data including SST, Chlorophyll a (Chl-a) and wind speed. Secondly, we demonstrated the satellite wind speed data are higher than those collected in land weather station (field wind speed = 0.8 × satellite wind speed), in order to re-evaluate the CO2 fluxes in the ECS. The average annual flux between 2003 and 2010 was constrained to -1.1 mol C m-2 y-1 as a net sink of atmospheric CO2 with the seasonal mean fluxes of -2.1 (Mar.-May), -0.3 (June-Aug.), -0.2 (Sep.-Nov.) and -1.9(Dec.-Jan.), respectively. The flux seasonality showed a strong sink in spring and winter, a sink-to-source transition during late summer – mid-fall period and a source-to-sink transition in late fall. Finally, the annual mean CO2 flux estimated in this study was nearly one half of those reported previously, indicating the importance of wind effect regarding spatial variability and reliability of wind field. Especially in some severe weather events, the more spatial gradients of wind speed would make more significant impact on the air-sea exchange flux of CO2 in continental margins.
Shadwick, Elizabeth Henderson. „Carbon Cycling in Canadian Coastal Waters: Process Studies of the Scotian Shelf and the Southeastern Beaufort Sea“. 2010. http://hdl.handle.net/10222/13107.
Der volle Inhalt der QuellePhD Thesis
Lai, Hsin-Yu, und 賴星宇. „Distribution and Air-Sea Exchange Flux of CO2 over the Marginal Seas surrounding Taiwan during Late Spring through Early Summer, 2008“. Thesis, 2009. http://ndltd.ncl.edu.tw/handle/x7pmza.
Der volle Inhalt der Quelle國立臺灣師範大學
海洋環境科技研究所
97
The distribution of CO2 in the surface water and the sea-air flux exchange in the sea areas around Taiwan are investigated in this study, and to discuss the reason of variation and the relationship with the distribution of water mass. Automated Underway pCO2 System are used to detect the seawater and air fCO2 during the late spring and early summer of 2008, from May 28 to July 13, including the South China Sea(SCS), the West Philippine Sea(WPS), the Western Taiwan Coast(WTC), and the East China Sea(ECS). The range of the atmospheric fCO2 is 367.4~402.2 μatm and the peaks are found near lands (Taiwan, China, and Luzon Island), the difference of concentration up to 35 μatm. The ranges of the surface water fCO2 are as follows: SCS: 352.3~415.6 μatm(Avg.= 389.3±16.5, n=1400), WPS: 346.9~399.0 μatm(Avg.= 377.6±5.8, n=840), TS: 370.5~407.3 μatm(Avg.= 389.2±4.8, n=836), ECS: 162~707 μatm(Avg.=378±69, n=1497); and ECS has the highest variation up to 545 μatm. The lowest and second lowest values of fCO2(217、162 μatm) are found in Changjiang Plume and Minjiang Plume, increasing from west to east with longitude and opposite to the concentration of chl-a. It’s quite obvious that the gradient of seawater fCO2 increase with the decrease of the biomass of plankton. The high values of fCO2(707、676 μatm) are found in Changjiang Upwelling and Coastal Upwelling which have low temperature. These areas also have very low transmittance(13.9 %) and very high nutrients(NO2+NO3) and Chl-a(32.2 μM, 106.7 mg/m3). It’s speculated that the high fCO2 may come from the bottom water of Changjiang Upwelling and Coastal Upwelling. Water masses in SCS and WPS are more stable and have the fCO2 gradient increase from shelf to offshore because the low temperature and rich of chl-a in nearshore seawater make the fCO2 of water decrease. In offshore, the fCO2 of SCS and WPS are high in daytime and low at night(△fCO2 =7.9), mainly reflecting the temperature difference between day and night(0.2~0.3℃) because of low biological effect. The surface water fCO2 of WTC has few variations but the atmospheric fCO2 has regional peaks because it is influenced by terrigenous matter. Data in this study suggests that the sea areas around Taiwan served as a source of atmospheric fCO2 during late spring and early summer, and the sea-to-air CO2 flux in SCS is +1.74±2.06 mol C/m2/yr, in WPS is +0.54±0.59, in WTC is +0.29±0.18, and in the ECS is +0.28±4.94.
Lee, Mi-Shuan, und 李宓薰. „Variation of air-sea CO2 flux in surface water off southeast Taiwan in response to the passage of Typhoon Saola in 2012“. Thesis, 2013. http://ndltd.ncl.edu.tw/handle/94174732100875030064.
Der volle Inhalt der Quelle國立臺灣海洋大學
海洋環境化學與生態研究所
101
Previous studies suggest that strong winds can largely enhance air-sea CO2 exchange flux during the passage of typhoon. Understanding how air-sea CO2 exchange flux would response to the passage of typhoon is therefore essential to better quantify the carbon budget in the subtropical oceans. However, limited to the rough sea conditions and cruise arrangement, the field data of air-sea CO2 exchange flux just before and after typhoon passage are scarce. In this study, two cruises (OR2 1893, 2012/7/26-30 and OR2 1894B, 2012/8/4-6) off the southeast Taiwan were fortuitously conducted just pre- and post-Typhoon Saola passage (2012/8/1-3) in summer 2012, which thus provide a unique opportunity to examine the response of air-sea CO2 exchange flux to typhoon passage in the subtropical ocean. The results show that ∆pCO2 (the difference of partial pressure of CO2 between the surface water and the air = pCO2sw – pCO2air) ranged between -37 to 41 and -36 to 38 atm before and after the typhoon passage, respectively. The source area is generally associated with the occurrence of high pCO2sw, while the sink area is coincident with the appearance of high pCO2air, which may be resulted from the air mass from land. The averaged air-sea CO2 exchange flux was -0.05 and 0.05 mmolC m-2 day-1 before and after the typhoon passage, respectively, suggesting that the study area turned from a sink of atmospheric CO2 pre-typhoon passage to a CO2 source post-typhoon passage. The wind speeds difference between the pre- and post-typhoon periods was not significant so that it only play a minor role on the variation of air-sea CO2 flux in response to the typhoon passage. Nonetheless, the elevated wind speed during the period of typhoon passage might lead to CO2 efflux increase by about 7 times (~0.48 mmolC m-2 day-1). Furthermore, the amount of CO2 uptake during the non-typhoon period in summer was estimated to be about 4.25 mmolm-2, while the amount of CO2 release during the typhoon period was about 4.32 mmolm-2. In other words, the CO2 uptake during the non-typhoon period was almost totally release back to the atmosphere during the typhoon period. As a result, the study area was nearly neutral to the atmospheric CO2 in summer 2012. Finally, our result generally confirms the previous findings that the passage of typhoon may enhance CO2 release from ocean to the atmosphere in the subtropical oceans, which may represent a positive feedback to global warming.