Heat budget of the surface mixed layer south of Africa     

Vincent Faure  Michel Arhan  Sabrina Speich  Sergey Gladyshev 《Ocean Dynamics》2011,61(10):1441-1458

ARGO hydrographic profiles, two hydrographic transects and satellite measurements of air–sea exchange parameters were used to characterize the properties and seasonal heat budget variations of the Surface Mixed Layer (SML) south of Africa. The analysis distinguishes the Subtropical domain (STZ) and the Subantarctic Zone (SAZ), Polar Frontal Zone (PFZ) and Antarctic Zone (AZ) of the Antarctic Circumpolar Current. While no Subantarctic Mode Water forms in that region, occurrences of deep SML (up to ∼450 m) are observed in the SAZ in anticyclones detached from the Agulhas Current retroflection or Agulhas Return Current. These are present latitudinally throughout the SAZ, but preferentially at longitudes 10–20° E where, according to previous results, the Subtropical Front is interrupted. Likely owing to this exchange window and to transfers at the Subantarctic Front also enhanced by the anticyclones, the SAZ shows a wide range of properties largely encroaching upon those of the neighbouring domains. Heat budget computations in each zone reveal significant meridional changes of regime. While air–sea heat fluxes dictate the heat budget seasonal variability everywhere, heat is mostly brought through lateral geostrophic advection by the Agulhas Current in the STZ, through lateral diffusion in the SAZ and through air–sea fluxes in the PFZ and AZ. The cooling contributions are by Ekman advection everywhere, lateral diffusion in the STZ (also favoured by the ∼10° breach in the Subtropical Front) and geostrophic advection in the SAZ. The latter likely reflects an eastward draining of water warmed through mixing of the subtropical eddies.  相似文献   

The many faces of local community: Exploring lay conceptualizations of the Norwegian lokalsamfunn     

Sabrina Scherzer  Nina Gunnerud Berg  Haakon Lein 《Norsk geografisk tidsskrift. Norwegian journal of geography》2020,74(3):152-164

ABSTRACT

Despite much attention paid to the topic of community in academic literature and policy documents, there is a relative lack of knowledge about what laypersons perceive as a local community. Based on data from a national survey, the authors examine how c.1400 Norwegians conceptualized local community – lokalsamfunn in Norwegian. They reveal some of the linguistic and conceptual aspects of local community as a term, in addition to tendencies and patterns among the survey responses. The respondents’ conceptualizations contained references to lokalsamfunn variously as a geographical area, people and relations, activities and involvement, attachment to place and people, and provider of local goods and services. Their main emphasis was on lokalsamfunn as a spatial unit. However, the responses contained relatively few references to the relational aspects of lokalsamfunn. The authors conclude that a common, lay understanding may be that lokalsamfunn is a vaguely defined but limited geographical unit filled with people who to varying degrees know each other and interact. Concerning policymaking aimed at fostering communal well-being, the authors hold that any community-based programming requires intricate knowledge of the people who form the community, since without community interaction and a degree of social cohesion any envisioned programmes may not succeed.  相似文献   

Evaluating water management processes in Germany: conceptual approach and practical applications     

Sabrina Kirschke  Jeanette Völker  Sandra Richter 《Environmental Earth Sciences》2016,75(14):1098

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How do Canadian media report climate change impacts on health? A newspaper review     

King  Nia  Bishop-Williams  Katherine E.  Beauchamp  Sabrina  Ford  James D.  Berrang-Ford  Lea  Cunsolo  Ashlee  Team  IHACC Research  Harper  Sherilee L. 《Climatic change》2019,152(3-4):581-596

Climatic Change - Research on climate change media coverage is growing. Few studies, however, have investigated how the media portrays climate change impacts on human health. This review,...  相似文献   

Coordination of boron in nominally boron-free rock forming silicates: Evidence for incorporation of BO₃ groups in clinopyroxene   总被引：1，自引：0，他引：1  

Ulf Hålenius  Henrik Skogby  Sabrina Nazzareni  Jeppa Resmark 《Geochimica et cosmochimica acta》2010,74(19):5672-1594

To explore mechanisms of B-incorporation in common chain silicates we have investigated synthetic diopside samples produced under boron-saturated conditions by ¹¹B and ²⁹Si magic-angle spinning (MAS) NMR and single-crystal NRA, FTIR, EMP and XRD/SREF techniques. Our samples contain 0.14-0.65 wt.% B₂O₃. NMR reveals that B is predominantly present in trigonal coordination in the clinopyroxene structure. This observation is supported by vibrational bands characteristic for B-O stretching in BO₃ groups in the range 1250-1400 cm⁻¹ in polarised single crystal FTIR-spectra. Single crystal structure refinements suggest that boron replaces Si at the T site. Combined, these results suggest that boron replacement for Si at the T-site leads to disruption of one of the T-O bonds of the nominal clinopyroxene structure resulting in replacement of SiO₄ tetrahedra by BO₃ groups. Our results show that high concentrations of boron can be incorporated in the nominally boron-free diopside. Elevated B-concentrations in the present calcic clinopyroxenes are accompanied by modifications of the diopside crystal structure involving the breaking of one T-O bond and simultaneous formation of vacancies at the octahedral M2 site. These structural modifications destabilize the structure and constitute thereby limiting factors for incorporating higher boron concentrations in diopside.  相似文献   

Weathering of Valle Ricca stiff and jointed clay     

Francesca Bozzano  Mario Gaeta  Sabrina Marcoccia   《Engineering Geology》2006,84(3-4):161-182

The study proposes a weathering model of Pliocene–Pleistocene stiff and jointed blue-grey clay transforming into yellow clay. Physical, mineralogical, chemical and textural changes, as well as the weathering profile were investigated in a quarry of central Italy. Based on geological records and inferences, these changes are likely to have occurred within a time-span of about 50,000 years BP, upon overburden stress unloading and in a stress regime that is locally controlled by suction. Weathering propagated into the clay at a rate of about 0.3 mm/year and was enhanced by the enlargement of the pre-existing tectonic discontinuities and by the formation of new joints. A mass loss of about 22–25 wt.% was calculated. Considering Fe and P as immobile elements, the individual oxides contribute to mass loss in the following order: SiO₂ > CaO = CO₂ > Al₂O₃ > MgO > K₂O > S > Na₂O > TiO₂ > MnO. The Fe₂O₃ / (Fe₂O₃ + FeO) ratio varies from 9–29% in the blue-grey clay to 75–82% in the yellow one. Oxidation and/or dissolution of 7 Å-Fe²⁺-bearing clay minerals, mica-like minerals and calcite and parallel increase of smectite and Fe-hydroxides play a critical role in the chemical changes and explain the higher plasticity of the yellow clay with respect to the blue-grey one. The role of water during the weathering process was inferred to occur in cyclical steps: 1) seepage of meteoric water; 2) dissemination of highly oxidizing meteoric water; 3) triggering of oxidation and dissolution of minerals; 4) water evaporation; 5) partial migration of the elements contained in the aqueous solution and consequent deposition of minerals in the joints.  相似文献   

Reconstruction of the Sunspot Number Source Database and the 1947 Zurich Discontinuity     

Clette  Frédéric  Lefèvre  Laure  Bechet  Sabrina  Ramelli  Renzo  Cagnotti  Marco 《Solar physics》2021,296(9):1-16

Solar Physics - The final version (V.19) of the total solar irradiance data from the SOlar Radiation and Climate Experiment (SORCE) Total Irradiance Monitor has been released. This version includes...  相似文献