Skill assessment of three earth system models with common marine biogeochemistry   总被引：1，自引：0，他引：1  

Roland Séférian  Laurent Bopp  Marion Gehlen  James C. Orr  Christian Ethé  Patricia Cadule  Olivier Aumont  David Salas y Mélia  Aurore Voldoire  Gurvan Madec 《Climate Dynamics》2013,40(9-10):2549-2573

We have assessed the ability of a common ocean biogeochemical model, PISCES, to match relevant modern data fields across a range of ocean circulation fields from three distinct Earth system models: IPSL-CM4-LOOP, IPSL-CM5A-LR and CNRM-CM5.1. The first of these Earth system models has contributed to the IPCC 4th assessment report, while the latter two are contributing to the ongoing IPCC 5th assessment report. These models differ with respect to their atmospheric component, ocean subgrid-scale physics and resolution. The simulated vertical distribution of biogeochemical tracers suffer from biases in ocean circulation and a poor representation of the sinking fluxes of matter. Nevertheless, differences between upper and deep ocean model skills significantly point to changes in the underlying model representations of ocean circulation. IPSL-CM5A-LR and CNRM-CM5.1 poorly represent deep-ocean circulation compared to IPSL-CM4-LOOP degrading the vertical distribution of biogeochemical tracers. However, their representations of surface wind, wind stress, mixed-layer depth and geostrophic circulations (e.g., Antarctic Circumpolar Current) have been improved compared to IPSL-CM4-LOOP. These improvements result in a better representation of large-scale structure of biogeochemical fields in the upper ocean. In particular, a deepening of 20–40 m of the summer mixed-layer depth allows to capture the 0–0.5 μgChl L^?1 concentrations class of surface chlorophyll in the Southern Ocean. Further improvements in the representation of the ocean mixed-layer and deep-ocean ventilation are needed for the next generations of models development to better simulate marine biogeochemistry. In order to better constrain ocean dynamics, we suggest that biogeochemical or passive tracer modules should be used routinely for both model development and model intercomparisons.  相似文献   

Earthquake deformation in the northwestern Sierras Pampeanas of Argentina based on seismic waveform modelling     

Patricia Alvarado  Victor A. Ramos 《Journal of Geodynamics》2011

We investigate the seismic properties of modern crustal seismicity in the northwestern Sierras Pampeanas of the Andean retroarc region of Argentina. We modelled the complete regional seismic broadband waveforms of two crustal earthquakes that occurred in the Sierra de Velasco on 28 May 2002 and in the Sierra de Ambato on 7 September 2004. For each earthquake we obtained the seismic moment tensor inversion (SMTI) and tested for its focal depth. Our results indicate mainly thrust focal mechanism solutions of magnitudes M_w 5.8 and 6.2 and focal depths of 10 and 8 km, respectively. These results represent the larger seismicity and shallower focal depths in the last 100 years in this region. The SMTI 2002 and 2004 solutions are consistent with previous determinations for crustal seismicity in this region that also used seismic waveform modelling. Taken together, the results for crustal seismicity of magnitudes ≥5.0 in the last 30 years are consistent with an average P-axis horizontally oriented by an azimuth of 125° and T-axis orientation of azimuth 241° and plunge 58°. This modern crustal seismicity and the historical earthquakes are associated with two active reverse faulting systems of opposite vergences bounding the eastern margin of the Sierra de Velasco in the south and the southwestern margin of the Sierra de Ambato in the north. Strain recorded by focal mechanisms of the larger seismicity is very consistent over this region and is in good agreement with neotectonic activity during the last 11,000 years by Costa (2008) and Casa et al. (in press); this shows that the dominant deformation in this part of the Sierras Pampeanas is mainly controlled by contraction. Seismic deformation related to propagation of thrusts and long-lived shear zones of this area permit to disregard previous proposals, which suggested an extensional or sinistral regime for the geomorphic evolution since Pleistocene.  相似文献   

Composition and structural aspects of naturally occurring ferrihydrite     

A. Cristina Cismasu  F. Marc Michel  A. Patricia Tcaciuc  Tolek Tyliszczak  Gordon E. Brown  Jr 《Comptes Rendus Geoscience》2011,343(2-3):210-218

A series of naturally occurring ferrihydrites sampled from an acid mine drainage environment were characterized and compared with synthetic 2-line ferrihydrite using high energy X-ray total scattering and pair distribution function analysis, Scanning Transmission X-ray Microscopy (STXM), Transmission Electron Microscopy (TEM), BET N₂ surface area measurements, and chemical extractions in order to place constraints on their structural and physical properties as a function of composition. Overall, the short- and intermediate-range ordering of the natural samples is comparable to synthetic ferrihydrite. However, with increasing Al, Si, and organic matter contents, a decrease in particle size and an increase in structural disorder were observed. Silica is suspected to have a pronounced effect on the crystallinity of ferrihydrite as a result of its inhibitory effect on Fe polymerization and particle growth, and it is likely complexed at the surfaces of ferrihydrite nanoparticles. Aluminum, on the other hand may substitute for Fe³⁺ in natural ferrihydrite. Organic matter is pervasive and intimately associated with ferrihydrite aggregates, and its presence during ferrihydrite precipitation may have contributed to additional structural disorder. The increase in impurity content affects not only the particle size and structural order of ferrihydrite but may also have a significant effect on its surface reactivity.  相似文献   

Is there enough zooplankton to feed forage fish populations off Peru? An acoustic (positive) answer     

Michael Ballón  Arnaud Bertrand  Anne Lebourges-Dhaussy  Mariano Gutiérrez  Patricia Ayón  Daniel Grados  François Gerlotto 《Progress in Oceanography》2011,91(4):360-381

The Northern Humboldt Current system (NHCS) produces more fish per unit area than any other region in the world. Although the system produces enough macrozooplankton to sustain its high production of forage fish, the paucity of information on macrozooplankton hampers research into the system. In this study, we estimated the biomass of the epipelagic crustacean macrozooplankton from the NHCS during both austral summer and spring 2005. To do this, we developed a bi-frequency acoustic method and extracted high-resolution information on the biomass and the patterns of distribution of crustacean macrozooplankton, fish and other marine compartments. We found that, although macrozooplankton comprises a number of distinct organisms, the euphausiids were the zooplankton group that better fitted the patterns from independent net sampling zooplankton data. Also, the similarities between the nocturnal patterns of size and biomass macrozooplankton distribution from this study and the known patterns of euphausiids, in particular Euphausia mucronata, suggest that euphausiids were the main constituent of the estimated nocturnal acoustic macrozooplankton biomass even if other organisms such as large copepods may have contributed considerably to the macrozooplankton biomass. The total macrozooplankton biomass was estimated to about 105 g m⁻², i.e., two to five times more than previous estimates. This direct biomass estimation of macrozooplankton is in agreement with the new findings in trophic ecology indicating that forage fish consume mainly macrozooplankton. This high biomass also supports the current hypotheses explaining the NHCS high fish production. Using the method, we are able to revisit present-day and historical acoustic databases and extract high-resolution data on macrozooplankton, a key ecological compartment of the ecosystem. Since zooplankton is the link between the physically driven primary producers and the biologically driven tertiary consumers, this information is essential to achieve a mechanistic understanding of the system, from physics to top predators.  相似文献   

Trace metals (Cd, Cr, Cu, Fe, Ni, Pb, and Zn) in feathers of Black-browed Albatross Thalassarche melanophrys attending the Patagonian Shelf     

Seco Pon JP  Beltrame O  Marcovecchio J  Favero M  Gandini P 《Marine environmental research》2011,72(1-2):40-45

We investigated the concentrations of cadmium, chromium, copper, iron, nickel, lead and zinc among feather tissues in sexes of Black-browed Albatross Thalassarche melanophrys killed in longliners off Argentina in 2005. We found no different metal concentration with sex for cadmium, copper, iron, lead and zinc in feathers of adult birds, though there were significant body-size differences between sexes. However, the concentrations of trace metals differed significantly among the type of feather within individual bird. The mean concentrations of copper, iron, and zinc in breast feathers of T.?melanophrys were lower than those reported for the species from Georgias del Sur/South Georgia, the southern Indian Ocean and for other seabirds' worldwide. While cadmium fall within the known range of concentrations for bird feathers lead were not. Our results may be indicating that level of pollution in Patagonia may not be as negligible as previously thought at least for some trace metals.  相似文献   

Surface Charge Concentrations on Silica in Different 1.0 M Metal-Chloride Background Electrolytes and Implications for Dissolution Rates     

Magnus Karlsson  Colin Craven  Patricia M. Dove  William H. Casey 《Aquatic Geochemistry》2001,7(1):13-32

The empirical rate laws formulated to describe the dissolution rates of oxide minerals include the surface charge concentration that results from the protonation and deprotonation of surface functional groups. Previous experiments on quartz and silica have shown that dissolution rates vary as a function of different background electrolyte solutions, however, such experiments are often conducted at elevated temperatures where it is difficult to estimate surface charge along with the dissolution rates. In the present study we measuresurface charge concentrations for silica in different electrolyte solutions at 298 K in order to quantify the extent to which the different counterions could affect the dissolution rates through their influence on the surface charge concentrations. The experimental solutions in the electrolyte series: LiCl, NaCl, KCl, RbCl, CaCl₂, SrCl₂ and BaCl₂ were prepared to maintain a constant metal concentration of 1.0 M. For the alkali-metal chlorides, the surface charge concentrations correlate with the size of the hydrated alkali metal, consistent with the idea that these counterions affect charge via outer-sphere coordination that shield proton surface complexes from one another. The reactivity trend for alkaline-earth cations is less clear, but the data demonstrate distinct differences in the acid-base propertiesof the silica surface in these different electrolytes. We then discuss how these trends are manifested in the rate equations used to interpret dissolution experiments.  相似文献   

Book reviews     

David K. Rea  Dirk Verschuren  Joseph R. Desloges  Patricia M. Anderson 《Journal of Paleolimnology》1996,16(3):357-295

  相似文献   

Chemical and geological control of spring water in Eastern Guaniguanico mountain range, Pinar del Rìo, Cuba     

Juan Reynerio Fagundo-Castillo  Joel José Carrillo-Rivera  Iñaki Antigüedad-Auzmendi  Patricia González-Hernández  Roberto Peláez-Díaz  Rebeca Hernández-Díaz  Dámaso Cáceres-Govea  José Ramón Hernández-Santana  Margaret Suárez-Muñoz  Clara Melián-Rodríguez  Mónica Rodríguez-Piña 《Environmental Geology》2008,55(2):247-267

Flows of different hierarchy, which travel through limestone, schist, sandstone and ultra-basic rocks, with ages from the Paleocene to the Jurassic, at Sierra del Rosario, Pinar del Río, Cuba, were characterized. The waters were sampled from 1984 until 2004 and the data were statistically processed by means of chemical equilibrium and physico-chemical models, under a flow system view of interpretation. Results demonstrate that the physico-chemical properties of the water are controlled by water–rock interaction resulting from residence time since rainwater infiltrate and the path it follows to the discharge zone and the type of aquifer material the different groundwater flows are in contact with. Geochemical indices allow the definition of the different types of flow (local, intermediate, regional) to be characterized, permitting a further definition of the different flow systems and rock type involved, as well as its use for water supply and medical use. The main geochemical processes which control the chemical composition acquisitions mode are: congruent dissolution of calcite, dolomite, and halite; incongruent dissolution of plagioclase and microcline minerals; pyrite oxidation, sulphate reduction, and silica dissolution at the surface or silica precipitation at deep saturation and circulation zones.  相似文献   

The Decision‐Making/Accountability Spatial Incongruence Problem for Research Linking Environmental Science and Policy          下载免费PDF全文

Patricia Solís  Jennifer K. Vanos  Robert E. Forbis Jr. 《Geographical review》2017,107(4):680-704

Increasingly, scholars engage policy makers around fundamental, complex questions on environmental change in interdisciplinary settings. Researchers attempting to develop robust contributions to knowledge that can support policymaker understandings in this context face significant inferential challenges in dealing with the spatial dimension of their phenomenon of interest. In this paper, we extend an understanding of well‐defined methodological challenges familiar to applied spatial scientists by explicitly articulating the Decision‐Making/Accountability, Spatial Incongruence Problem, or DASIP. Three case studies illustrate how spatial incongruences matter to researchers who work on complex, interdisciplinary problems, while seeking to understand decision‐making or policy‐related phenomenon: urban heat‐island mitigation research in Arizona, water transfer conflicts in Kansas, and hydraulic‐fracturing debates in Texas. With such examples, we aim to evoke a deeper understanding of this problem in applied research and also inspire thinking about how scholars might innovate methods for creating knowledge about environmental change that supports spatially accountable decision making.  相似文献   

Influences of physical structures on urban energy budgets   总被引：1，自引：0，他引：1  

Werner H. Terjung  Patricia A. O'Rourke 《Boundary-Layer Meteorology》1980,19(4):421-439

Four typical urban surroundings were modelled, ranging from high-rise structures to low buildings and combinations thereof. These building systems were exposed to typical summer and winter climatic scenarios for latitudes 10, 34, and 50 N. Systematic variations of interior building temperatures were also introduced. The resultant changes in the components of the systems' energy budgets were examined with respect to cause and effect. The simulations produced a variety of unexpected features which intuitively had not been anticipated. It is believed that energy budget features of real cities cannot vary drastically from those simulated, and described in this report.  相似文献