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| Registros recuperados: 69 | |
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| Mahan, N. Claude; Bamba, S. Barthélémy; Aman, Angora. |
| Depuis 1977, le Centre de Recherches Océanologiques (CRO) a entrepris des mesures quotidiennes de température de la mer le long des côtes ivoiriennes. Les remontées d'eaux froides qui affectent la côte ivoirienne présentent une forte variabilité à différentes échelles de temps et d'espace. Ces processus environnementaux complexes, irréguliers et difficiles à appréhender ont une grande influence sur un écosystème pélagique instable et par nature changeant (Arfi et al., 1995). Ces mesures répondent à un double objectif concernant l'étude saisonnière de l'upwelling côtier ivoiro-ghanéen pour prévoir les périodes et les zones favorables à la pêche sur le plateau continental ivoirien et à l'alimentation du projet GOOS (Global Ocean Observing System) de la... |
| Tipo: Journal Contribution |
Palavras-chave: Sea surface temperature; Sea level variations; Inshore stations. |
| Ano: 2008 |
URL: http://hdl.handle.net/1834/5748 |
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| Lambaerts, J.; Lapeyre, Guillaume; Plougonven, R.; Klein, Patrice. |
| Recent studies have revealed that strong sea surface temperature (SST) fronts, on the scale of a Western Boundary Current, significantly affect not just the Marine Boundary Layer but the entire troposphere. This has aroused renewed interest in air-sea interactions. The present study investigates the atmospheric response to fixed SST anomalies associated with mesoscale oceanic eddies and submesoscale filaments, using idealized simulations. Our main result is that in weak wind conditions, the vertical velocity in the planetary boundary layer (PBL) is linearly proportional to the SST Laplacian. This is established by a quantitative analysis in the spatial space as well as in the spectral space. Comparing the responses to two different SST fields shows that... |
| Tipo: Text |
Palavras-chave: Air-sea interactions; Boundary layer; Sea surface temperature. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00169/28047/26247.pdf |
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| He, Juan; Zhao, Meixun; Li, Li; Wang, Hui; Wang, Pinxian. |
| High-resolution molecular abundance records for several marine biomarkers during the last glacial and Holocene have been generated for core MD05-2904 (19 degrees 27.32'N, 116 degrees 15.15'E, 2066 in water depth) from the northern South China Sea. The U-37(K') SST record indicates a 4.4 degrees C cooling during the Last Glacial Maximum for this site, consistent with previous reconstructions. The contents Of C-37 alkenones, dinosterol, brassicasterol, and C-30 alkyl diols are used as productivity proxies for haptophytes, dinoflagellates, diatoms, and eustigmatophytes, respectively. These records reveal that both individual phytoplankton group and total productivity increased by several factors during the LGM compared with those for the Holocene, in response... |
| Tipo: Text |
Palavras-chave: Biomarkers; Paleo-productivity; Community structure; Sea surface temperature; South China Sea. |
| Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/00207/31845/30258.pdf |
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| Schneider, E.K.; Kirtman, B.P.; Wu, Z.. |
| The low frequency sea surface temperature (SST) variability in the North Atlantic is studied using the Center for Ocean-Land-Atmosphere Studies (COLA) anomaly coupled general circulation model. The main focus is placed on the relative roles of stable and unstable coupled feedbacks in inducing the low frequency SST variability in various regions of the North Atlantic. To examine this question, a recently developed coupling technique, interactive ensembles, is applied to reduce the strength of “weather noise” in the model and isolate the atmospheric feedback to boundary forcing. |
| Tipo: Journal Contribution |
Palavras-chave: Sea surface temperature. |
| Ano: 2004 |
URL: http://hdl.handle.net/1834/508 |
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| Lopes Dos Santos, Raquel A.; Spooner, Michelle I.; Barrows, Timothy T.; De Deckker, Patrick; Damste, Jaap S. Sinninghe; Schouten, Stefan. |
| Several proxies have been developed to reconstruct past sea surface temperature (SST), but different proxies may reflect temperatures of different seasons and each proxy is characterized by certain uncertainties. Therefore, a multiproxy approach is preferred to precisely reconstruct SST. Here, we reconstruct SST of the ocean offshore southeastern Australia (Murray Canyons area) for the last ~135 ka using three independent organic proxies (TEXH86 based on glycerol dialkyl glycerol tetraethers (GDGTs), UK'37 based on alkenones, and LDI based on long-chain diols) in addition to foraminiferal faunal assemblages. The organic proxy records show similar trends, with the highest temperature (21°C for UK'37 and TEXH86, and 25°C for LDI) during the last interglacial... |
| Tipo: Text |
Palavras-chave: Sea surface temperature; LDI index; TEX86H index; U-37(K') index; Foraminiferal assemblages; SE Australia. |
| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00246/35763/34274.pdf |
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| Harada, Naomi; Ninnemann, Ulysses; Lange, Carina B.; Marchant, Margarita E.; Sato, Miyako; Ahagon, Naokazu; Pantoja, Silvio. |
| We show environmental and nitrogen cycle changes between 13 and 2.5 kyr BP (from the latest deglaciation to the Holocene) based on biogeochemical records in a sediment core from the Pacific entrance of the Strait of Magellan. Organic carbon, total nitrogen, and C-37 alkenone contents were low during 13-9 kyr BP but increased rapidly at 8 kyr BP. The relative contribution of tetra-unsaturated C-37 alkenone, used as a salinity proxy, suggests low salinity during 13-9 kyr BP changing to high salinity at 8 kyr BP. Planktic foraminifer data showed that Globigerina bulloides was more abundant during the deglacial-early Holocene than in the mid-late Holocene, whereas abundances of Neogloboquadrina pachyderma showed the opposite pattern. This evidence plus... |
| Tipo: Text |
Palavras-chave: Biogenic components; Delta C-13; Delta N-15; Planktic foraminifera; Alkenone; Sea surface temperature; Southern Patagonia. |
| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00264/37548/36825.pdf |
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| Roa Pascuali, Liliana; Demarcq, Herve; Nieblas, Anne-elise. |
| In order to optimize frontal detection in sea surface temperature fields at 4 km resolution, a combined statistical and expert-based approach is applied to test different spatial smoothing of the data prior to the detection process. Fronts are usually detected at 1 km resolution using the histogram-based, single image edge detection (SIED) algorithm developed by Cayula and Cornillon in 1992, with a standard preliminary smoothing using a median filter and a 3 × 3 pixel kernel. Here, detections are performed in three study regions (off Morocco, the Mozambique Channel, and north-western Australia) and across the Indian Ocean basin using the combination of multiple windows (CMW) method developed by Nieto, Demarcq and McClatchie in 2012 which improves on the... |
| Tipo: Text |
Palavras-chave: Mesoscale thermal fronts; Preliminary smoothing; Sea surface temperature; 4 km resolution; Gradient intensity classification; Expert-based approach; Detection efficiency; Indian Ocean. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00269/37998/42023.pdf |
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| Isern-fontanet, J.; Hascoet, Erwan. |
| The noise present in infrared satellite measurements of sea surface temperature (SST) hampers the use of surface quasi-geostrophic (SQG) equations to diagnose ocean dynamics at high resolutions. Here we propose a methodology to reduce the contribution of noise when diagnosing surface vorticity, divergence, and vertical velocity from SST able to retain the dynamics at scales of a few kilometers. It is based on the use of denoising techniques with curvelets as basis functions and the application of a selective low-pass filters to improve the reconstruction of surface upwelling/downwelling patterns. First, it is tested using direct numerical simulations of SQG turbulence and then applied to diagnose low-frequency vertical velocity patterns from real MODIS... |
| Tipo: Text |
Palavras-chave: Sea surface temperature; Surface quasi-geostrophy; Remote sensing; Vertical velocity; Ocean submesoscales; Image denoising. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00170/28162/26391.pdf |
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| Royer, Francois; Fromentin, Jean-marc. |
| This paper provides an exploratory analysis aiming to seek whether the colour of environmental noise theory could help in understanding the intriguing reproductive strategy of Atlantic bluefin tuna (BFT). A frequency-based approach based on spectral exponents, f(beta) with beta < 0, is chosen and applied on 10 biogeographical provinces covering the North Atlantic. The major BFT spawning area, i.e. the Mediterranean Sea, was the only one to display a pink power spectrum, whereas open ocean regions displayed more reddened fluctuations, i.e. greater variance at low frequencies. Environmental noise in the Mediterranean could, thus, offer more favourable characteristics on the long-term than the open ocean. The implications of these findings are discussed in... |
| Tipo: Text |
Palavras-chave: Thunnus thynnus; Spectral analysis; Spawning; Sea surface temperature; Environmental noise. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2437.pdf |
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| Picart, Stephane Saux; Tandeo, Pierre; Autret, Emmanuelle; Gausset, Blandine. |
| Machine learning techniques are attractive tools to establish statistical models with a high degree of non linearity. They require a large amount of data to be trained and are therefore particularly suited to analysing remote sensing data. This work is an attempt at using advanced statistical methods of machine learning to predict the bias between Sea Surface Temperature (SST) derived from infrared remote sensing and ground “truth” from drifting buoy measurements. A large dataset of collocation between satellite SST and in situ SST is explored. Four regression models are used: Simple multi-linear regression, Least Square Shrinkage and Selection Operator (LASSO), Generalised Additive Model (GAM) and random forest. In the case of geostationary satellites for... |
| Tipo: Text |
Palavras-chave: Machine learning; Systematic error; Sea surface temperature; Random forest. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00426/53797/54721.pdf |
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| Small, David; Austin, William; Rinterknecht, Vincent. |
| A sediment core from the north-east North Atlantic contains high-resolution co-registered foraminiferal O-18 and ice-rafted detritus (IRD) records for the last deglaciation. These reveal a distinct ice-rafting event that occurred at the time of Greenland Interstade 1d (GI-1d), a feature also seen in other high-resolution cores from the North Atlantic. The occurrence of a geographically widespread peak in IRD at ice distal sites at a time when increased freshwater flux to the surface ocean is inferred to have caused rapid cooling suggests a mechanistic link between the processes, analogous to the Younger Dryas (GS-1) cooling episode. The general absence of IRD at southern locations at other times during GI-1 when the flux of icebergs from surviving ice... |
| Tipo: Text |
Palavras-chave: Deglaciation; Hydrography; Ice-rafted detritus; North Atlantic; Sea surface temperature. |
| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00291/40180/39238.pdf |
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| Ho, Sze Ling; Laepple, Thomas. |
| Knowledge of the magnitude of the Last Glacial Maximum (LGM) cooling is a useful constraint for estimating the climate sensitivity used in projecting future climate change. Proxy comparison, especially that between the alkenone-based U-37(K ') and the archaeal tetraether-based TEX86, has been increasingly applied in paleoceanographic studies as a measure to better constrain proxy-derived temperature estimates. In this study, we compile and compare published multiproxy (U-37(K ') and TEX86H) records of glacial cooling measured on the same sediment cores. In spite of the diversity in oceanographic and sedimentation settings spanned by the study sites, we find that the TEX86H-derived mean tropical LGM cooling is approximately twice as strong as that suggested... |
| Tipo: Text |
Palavras-chave: Last Glacial Maximum; Sea surface temperature; Multiproxy; PMIP3; U-37(K '); TEX86H. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00352/46297/45933.pdf |
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| Drushka, Kyla; Asher, William E.; Sprintall, Janet; Gille, Sarah T.; Hoang, Clifford. |
| Surface salinity variability on O(1-10) km lateral scales (the submesoscale) generates density variability and thus has implications for submesoscale dynamics. Satellite salinity measurements represent a spatial average over horizontal scales of approximately 40-100 km but are compared to point measurements for validation, so submesoscale salinity variability also complicates validation of satellite salinities. Here, we combine several databases of historical thermosalinograph (TSG) measurements made from ships to globally characterize surface submesoscale salinity, temperature, and density variability. In river plumes; regions affected by ice melt or upwelling; and the Gulf Stream, South Atlantic, and Agulhas Currents, submesoscale surface salinity... |
| Tipo: Text |
Palavras-chave: Small scale processes; Freshwater; Fronts; Sea surface temperature; Oceanic variability. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00676/78805/81042.pdf |
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| Registros recuperados: 69 | |
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