Home Itens selecionados Provedores de dados OAI Créditos Sobre Ajuda

			Busca avançada
	Provedor de dados ArchiMer (3) Autor Bickert, Torsten (1) Dekkers, Mark J. (1) Johnson, J (1) Just, Janna (1) Lopes Dos Santos, Raquel A (1) Stevens, I (1) Van Hoesel, Annelies (1) Von Dobeneck, Tilo (1) Mais... Palavra-chave NW Africa (3) Paleoclimate (2) Afrique Nord-Ouest (1) Cape Ghir (1) Coastal upwelling (1) Environmental magnetism (1) IRM end-member modeling (1) Keywords: organic proxies (1) Magnetotactic bacteria (1) Meso-échelle (1) Mesoscale features (1) Modèle numérique (1) Numerical model (1) Productivity (1) SE Australia (1) SST (1) Terrigenous input (1) Upwelling (1) Vegetation (1) Mais... Tipo do documento Text (3) Ano 2012 (2) 2003 (1) País France (3) Idioma Inglês (3)		Ordenar por:  Relevância Autor Título Ano Registros recuperados: 3 Primeira ... 1 ... Última A numerical modelling study of upwelling filaments off the NW African coast ArchiMer Stevens, I; Johnson, J. A fine resolution (1/12degrees x 1/12degrees) primitive equation limited area model is constructed for the region off NW Africa in the eastern North Atlantic to examine the generation of cool upwelling filaments. A seasonal shift in the trade wind pattern leads to coastal upwelling and an equatorward coastal current. The filaments form at four preferred locations along the NW African coast between 25degreesN and 35degreesN, the largest filament being at Cape Ghir. The generation mechanism for the filaments is similar to the one proposed for filaments in the California current system. As a result of baroclinic instability meanders develop on the coastal current and transport cool upwelled water offshore to form the filaments. During the relaxation phase of... Tipo: Text Palavras-chave: Modèle numérique; Upwelling; Meso-échelle; Afrique Nord-Ouest; Cape Ghir; Numerical model; Coastal upwelling; Mesoscale features; NW Africa; Cape Ghir. Ano: 2003 URL: http://archimer.ifremer.fr/doc/00321/43247/42978.pdf Reconstruction of late Quaternary marine and terrestrial environmental conditions of Northwest Africa and Southeast Australia. A multiple organic proxy study using marine sediments ArchiMer Lopes Dos Santos, Raquel A. NW Africa and SE Australia are regions which are particularly vulnerable to climate change. In this thesis, organic proxies are used from marine sediment cores to reconstruct past environmental conditions from these areas. In sediments from NW Africa, the UK'37 showed an efficient proxy for sea surface temperature (SST) reconstruction, while the TEXH86 reconstructed thermocline temperatures. The UK'37 and TEXH86 records for the last 192 ka showed that periods of reduced AMOC coincide with a reduction in the vertical temperature gradient. Thus, variations in AMOC strength is a driver of the thermocline structure in the tropical Atlantic. Three independent organic proxies (UK’37,TEXH86 and LDI) were used to reconstruct SSTs for the last 135 ka in sediments... Tipo: Text Palavras-chave: Keywords: organic proxies; Paleoclimate; NW Africa; SE Australia; SST; Productivity; Vegetation. Ano: 2012 URL: https://archimer.ifremer.fr/doc/00494/60594/64078.pdf Signatures and significance of aeolian, fluvial, bacterial and diagenetic magnetic mineral fractions in Late Quaternary marine sediments off Gambia, NW Africa ArchiMer Just, Janna; Dekkers, Mark J.; Von Dobeneck, Tilo; Van Hoesel, Annelies; Bickert, Torsten. Two gravity cores retrieved off NW Africa at the border of arid and subtropical environments (GeoB 13602-1 and GeoB 13601-4) were analyzed to extract records of Late Quaternary climate change and sediment export. We apply end-member (EM) unmixing to 350 acquisition curves of isothermal remanent magnetization (IRM). Our approach enables to discriminate rock magnetic signatures of aeolian and fluvial material, to determine biomineralization and reductive diagenesis. Based on the occurrence of pedogenically formed magnetic minerals in the fluvial and aeolian EMs, we can infer that goethite formed in favor to hematite in more humid climate zones. The diagenetic EM dominates in the lower parts of the cores and within a thin near-surface layer probably... Tipo: Text Palavras-chave: IRM end-member modeling; NW Africa; Environmental magnetism; Magnetotactic bacteria; Paleoclimate; Terrigenous input. Ano: 2012 URL: https://archimer.ifremer.fr/doc/00265/37617/36987.pdf Registros recuperados: 3 Primeira ... 1 ... Última

Empresa Brasileira de Pesquisa Agropecuária - Embrapa Todos os direitos reservados, conforme Lei n° 9.610 Política de Privacidade Área restrita		Embrapa Parque Estação Biológica - PqEB s/n° Brasília, DF - Brasil - CEP 70770-901 Fone: (61) 3448-4433 - Fax: (61) 3448-4890 / 3448-4891 SAC: https://www.embrapa.br/fale-conosco