An ensemble climate projection for Africa     

Carlo Buontempo  Camilla Mathison  Richard Jones  Karina Williams  Changgui Wang  Carol McSweeney 《Climate Dynamics》2015,44(7-8):2097-2118

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Stability of the sponge assemblage of Mediterranean coralligenous concretions along a millennial time span     

Marco Bertolino  Barbara Calcinai  Riccardo Cattaneo‐Vietti  Carlo Cerrano  Anna Lafratta  Maurizio Pansini  Daniela Pica  Giorgio Bavestrello 《Marine Ecology》2014,35(2):149-158

The Mediterranean coralligenous substratum is a hard bottom of biogenic origin, mainly composed of calcareous algae, growing in dim light conditions. Sponges are among of the most representative taxa of the coralligenous assemblages, with more than 300 recorded species of different habits: massive, erect, boring and insinuating. When sponges die, their siliceous spicules remain trapped in the biogenic concretion, offering the opportunity to describe the coralligenous spongofauna over a very long span of time, virtually dating back to a large part of the Holocene period. The data reported here were obtained from core samples collected from four coralligenous concretions. Each block was collected in a different locality of the Ligurian Sea: Santo Stefano Shoals, Bogliasco, Punta del Faro (Portofino Promontory) and Punta Manara. Radiocarbon age determinations indicate for these conglomerates a maximal age between 1600 and 3100 years. The spicules trapped in the cores show deep dissolution marks in the form of circular holes on their surface or present an enlargement of the axial canal. However, their original shape, generally intact, suggests the absence of mechanical injuries and allows a tentative identification at the species level. The analysis of these old spicules reveals an ancient sponge assemblage composed of 30 recognisable species. This indicates that almost one half of the sponge community today settled on coralligenous substrata has been present in the conglomerates for their entire existence.  相似文献   

How dynamical models can learn from the data��an example with a simplified ENSO model     

Heiko Paeth  Janna Lindenberg  Maik Kschischo  Andreas Hense 《Theoretical and Applied Climatology》2011,104(1-2):221-231

Most dynamical models of the natural system contain a number of empirical parameters which reflect our limited understanding of the simulated system or describe unresolved subgrid-scale processes. While the parameterizations basically introduce some uncertainty to the model results, they also hold the prospect of tuning the model. In general, a deterministic tuning is related to an inversion of the model which is often impossible or requires considerable computing effort for most climate models. Another way to adjust the model parameters to a specific observed process is stochastic fitting where a set of parameters and model output are taken as random variables. Here, we present a dynamical?Cstatistical approach with a simplified model of the El Ni?o?CSouthern Oscillation (ENSO) cycle whose parameters are adjusted to simulated and observed data by means of Bayesian statistics. As ENSO model, we employ the Schop?CSuarez delay oscillator model. Monte Carlo experiments highlight the large sensitivity of the model results to varied model parameters and initial values. The statistical adjustment is done by Bayesian model averaging of the Monte Carlo experiments. Applying the method to simulated data, the posterior ensemble mean is much closer to the reference data than the prior ensemble mean. The learning effect of the model is evident in the leading empirical orthogonal functions and statistically significant in the mean state. When the method is applied to the observed ENSO time series, the ENSO model in its classical setup is not able to account for the temporally varying periodicity of the observed ENSO phenomenon. An improved setup with continuous adjustment periods and extended parameter range is developed in order to allow the model to learn from the data gradually. The improved setup leads to promising results during the twentieth century and even a weak forecast skill over 6?months. Thus, the described method offers a promising tool for data assimilation in dynamical weather and climate models. However, the simplified ENSO model is barely appropriate for operational ENSO forecasts owing to its limited physical complexity.  相似文献   

Probabilistic seismic hazard assessment for Thailand   总被引：3，自引：1，他引：2  

Teraphan Ornthammarath  Pennung Warnitchai  Kawin Worakanchana  Saeed Zaman  Ragnar Sigbj?rnsson  Carlo Giovanni Lai 《Bulletin of Earthquake Engineering》2011,9(2):367-394

A set of probabilistic seismic hazard maps for Thailand has been derived using procedures developed for the latest US National Seismic Hazard Maps. In contrast to earlier hazard maps for this region, which are mostly computed using seismic source zone delineations, the presented maps are based on the combination of smoothed gridded seismicity, crustal-fault, and subduction source models. Thailand’s composite earthquake catalogue is revisited and expanded, covering a study area limited by 0°–30°N Latitude and 88°–110°E Longitude and the instrumental period from 1912 to 2007. The long-term slip rates and estimates of earthquake size from paleoseismological studies are incorporated through a crustal fault source model. Furthermore, the subduction source model is used to model the megathrust Sunda subduction zones, with variable characteristics along the strike of the faults. Epistemic uncertainty is taken into consideration by the logic tree framework incorporating basic quantities, such as different source modelling, maximum cut-off magnitudes and ground motion prediction equations. The ground motion hazard map is presented over a 10 km grid in terms of peak ground acceleration and spectral acceleration at 0.2, 1.0, and 2.0 undamped natural periods and a 5% critical damping ratio for 10 and 2% probabilities of exceedance in 50 years. The presented maps give expected ground motions that are based on more extensive data sources than applied in the development of previous maps. The main findings are that northern and western Thailand are subjected to the highest hazard. The largest contributors to short- and long-period ground motion hazard in the Bangkok region are from the nearby active faults and Sunda subduction zones, respectively.  相似文献   

U and Th content in the Central Apennines continental crust: A contribution to the determination of the geo-neutrinos flux at LNGS     

M. Coltorti  R. Boraso  M. Morsilli  A. Riva  R. Tassinari  G. Di Carlo 《Geochimica et cosmochimica acta》2011,75(9):2271-2294

The regional contribution to the geo-neutrino signal at Gran Sasso National Laboratory (LNGS) was determined based on a detailed geological, geochemical and geophysical study of the region. U and Th abundances of more than 50 samples representative of the main lithotypes belonging to the Mesozoic and Cenozoic sedimentary cover were analyzed. Sedimentary rocks were grouped into four main “reservoirs” based on similar depositional settings and mineralogy. The initial assumption that similar chemico-physical depositional conditions would lead to comparable U and Th contents, was then confirmed by chemical analyses. Basement rocks do not outcrop in the area. Thus U and Th in the upper and lower crust of Valsugana and Ivrea-Verbano areas were analyzed. Irrespective of magmatic or metamorphic origin lithotypes were subdivided into a mafic and an acid reservoir, with comparable U and Th abundances.Based on geological and geophysical properties, relative abundances of the various reservoirs were calculated and used to obtain the weighted U and Th abundances for each of the three geological layers (sedimentary cover, upper and lower crust). Using the available seismic profile as well as the stratigraphic records from a number of exploration wells, a 3D modeling was developed over an area of 2° × 2° down to the Moho depth, for a total volume of about 1.2 × 10⁶ km³. This model allowed us to determine the volume of the various geological layers and eventually integrate the Th and U contents of the whole crust beneath LNGS.On this base the local contribution to the geo-neutrino flux (S) was calculated and added to the contribution given by the rest of the world, yielding a refined reference model prediction for the geo-neutrino signal in the Borexino detector at LNGS: S(U) = (28.7 ± 3.9) TNU and S(Th) = (7.5 ± 1.0) TNU. An excess over the total flux of about 4 TNU was previously obtained by Mantovani et al. (2004) who calculated, based on general worldwide assumptions, a signal of 40.5 TNU. The considerable thickness of the sedimentary rocks, almost predominantly represented by U- and Th-poor carbonatic rocks in the area near LNGS, is responsible for this difference. Thus the need for detailed integrated geological study is underlined by this work, if the usefulness of the geo-neutrino flux for characterizing the global U and Th distribution within the Earth’s crust, mantle and core is to be realized.  相似文献   

Ecosystem-based marine spatial management: Review of concepts, policies, tools, and critical issues   总被引：1，自引：0，他引：1  

Stelios Katsanevakis  Vanessa Stelzenmüller  Andy South  Thomas Kirk Sørensen  Peter J.S. Jones  Sandy Kerr  Fabio Badalamenti  Christos Anagnostou  Patricia Breen  Guillem Chust  Giovanni D’Anna  Mike Duijn  Tatiana Filatova  Fabio Fiorentino  Helena Hulsman  Kate Johnson  Aristomenis P. Karageorgis  Ingrid Kröncke  Simone Mirto  Carlo Pipitone  Susan Portelli  Wanfei Qiu  Henning Reiss  Dimitris Sakellariou  Maria Salomidi  Luc van Hoof  Vassiliki Vassilopoulou  Tomás Vega Fernández  Sandra Vöge  Anke Weber  Argyro Zenetos  Remment ter Hofstede 《Ocean & Coastal Management》2011,54(11):807-820

Conventional sectoral management and piecemeal governance are considered less and less appropriate in pursuit of sustainable development. Ecosystem based marine spatial management (EB-MSM) is an approach that recognizes the full array of interactions within an ecosystem, including human uses, rather than considering single issues, species, or ecosystem services in isolation. Marine spatial planning and ocean zoning are emerging concepts that can support EB-MSM. EB-MSM is driven by high-level goals that managers aim to achieve through the implementation of measures. High-level goals and objectives need to be translated into more operational objectives before specific targets, limits and measures can be elaborated.Monitoring, evaluation and adaptation are necessary to ensure that marine management measures are both effective and efficient. Solid monitoring frameworks are the foundation of adaptive management, as they provide the necessary information to evaluate performance and the effectiveness of management actions. Marine protected areas (MPAs) - possibly set up in networks - constitute a key component in EB-MSM policies and practises and have been applied as a cornerstone in conservation of marine biodiversity, management of fish populations, development of coastal tourism, etc. Moreover, MPA experiences have provided methods and concepts (such as zoning) to a wider EB-MSM context. The assignment of values to biophysical features of the marine environment allows the direct assessment of related management choices and may assist EB-MSM.A range of monetary valuation techniques have been proposed to reduce attributes of goods and services to a single metric. However, in the marine environment such an approach is often over simplistic, and thus less reductive techniques may be necessary. Rather than producing a single metric, the results of non-monetary assessments guide policy allowing weight to be given as necessary to potential areas of conflict and consensus.Strategies to take into account climate change effects and geohazard risks in EB-MSM have been applied or proposed worldwide. EB-MSM regimes must be alert to such risks and flexible to account for changes.  相似文献   

Surface atmospheric circulation patterns and associated minimum temperatures in the Maipo and Casablanca valleys, central Chile     

Carlo Montes  Ricardo C. Muñoz  Jorge F. Perez-Quezada 《Theoretical and Applied Climatology》2013,111(1-2):275-284

This paper analyzes the influence of circulation anomalies on the magnitude of minimum air temperature (T _min) at a daily scale in two important agricultural valleys of Chile (Maipo and Casablanca) during the period 2001–2007. A statistical classification of synoptic fields was performed, resulting in eight circulation patterns (CPs, 84 % of explained variance). The corresponding anomalies of T _min (AT_min) of each CP were analyzed in order to understand their synoptic-scale forcing mechanisms. Results showed a direct association between AT_min and the synoptic structure. The average weakening in sea level pressure (SLP) yields positive AT_min, while negative AT_min is associated with a strengthening in SLP. In the latter case, it was also found that a synoptic structure (10.2 % of frequency) corresponding to a migratory high-pressure system passing eastward across the Andes led to the lowest AT_min and a higher probability of frost in both valleys (22 % on average) in winter and springtime.  相似文献   

On the equations of the dynamics of the attracting point masses     

Carlo Morosi  Livio Pizzocchero 《Celestial Mechanics and Dynamical Astronomy》1990,48(1):1-21

On the equations of the dynamics of the attracting point masses  相似文献   

Cosmic microwave background polarisation: foreground contrast and component separation     

Carlo Baccigalupi   《New Astronomy Reviews》2003,47(11-12):1127

We evaluate the expected level of foreground contamination to the cosmic microwave background (CMB) polarised radiation, focusing on the diffuse emission from our own Galaxy. In particular, we perform a first attempt to simulate an all sky template of polarised emission from thermal dust. This study indicates that the foreground contamination to CMB B-modes is likely to be relevant on all frequencies, and even at high Galactic latitudes. We review the recent developments in the design of data analysis techniques dedicated to the separation of CMB and foreground emissions in multi-frequency observations, exploiting their statistical independence. We argue that the high quality and detail of the present CMB observations represent an almost ideal statistical dataset where these algorithms can operate with excellent performance. We explicitly show that the recovery of CMB B-modes is possible even if they are well below the foreground level, working at the arcminute resolution at an almost null computational cost. This capability well represents the great potentiality of these new data analysis techniques, which should be seriously taken into account for implementation in present and future CMB observations.  相似文献   

A review of near-surface QS estimation methods using active and passive sources     

Parolai  Stefano  Lai  Carlo G.  Dreossi  Ilaria  Ktenidou  Olga-Joan  Yong  Alan 《Journal of Seismology》2022,26(4):823-862

Journal of Seismology - Seismic attenuation and the associated quality factor (Q) have long been studied in various sub-disciplines of seismology, ranging from observational and engineering...  相似文献