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31.
Land surface processes and their initialisation are of crucial importance for Numerical Weather Prediction (NWP). Current land data assimilation systems used to initialise NWP models include snow depth analysis, soil moisture analysis, soil temperature and snow temperature analysis. This paper gives a review of different approaches used in NWP to initialise land surface variables. It discusses the observation availability and quality, and it addresses the combined use of conventional observations and satellite data. Based on results from the European Centre for Medium-Range Weather Forecasts (ECMWF), results from different soil moisture and snow depth data assimilation schemes are shown. Both surface fields and low-level atmospheric variables are highly sensitive to the soil moisture and snow initialisation methods. Recent developments of ECMWF in soil moisture and snow data assimilation improved surface and atmospheric forecast performance.  相似文献   
32.
Parametric models of heave, pitch and roll dynamics of a high-speed craft have been estimated for different wave incidence angles in the frequency domain. Several issues that make the identification problem interesting are the following: type of parameterization, starting values, non-quadratic functions, excitation signals and short data record. The method employed guarantees a fine linear approximation of the nonlinear dynamics of a fast ship for the ultimate goal of stabilization control to reduce motion sickness associated with heave, pitch and roll accelerations. In addition, the approach achieves high-quality starting values and avoids non-quadratic terms in the cost function, which results in less computational load and significantly more accurate models when compared with a previous method employed for the same problem.  相似文献   
33.
The use of standards in the geospatial domain, such as those defined by the Open Geospatial Consortium (OGC), for exchanging data has brought a great deal of interoperability upon which systems can be built in a reliable way. Unfortunately, these standards are becoming increasingly complex, making their implementation an arduous task. The use of appropriate software metrics can be very useful to quantify different properties of the standards that ultimately may suggest different solutions to deal with problems related to their complexity. In this regard, we present in this article an attempt to measure the complexity of the schemas associated with the OGC implementation specifications. We use a comprehensive set of metrics to provide a multidimensional view of this complexity. These metrics can be used to evaluate the impact of design decisions, study the evolution of schemas, and so on. We also present and evaluate different solutions that could be applied to overcome some of the problems associated with the complexity of the schemas.  相似文献   
34.
This paper presents the results of investigations of the generalized subsidence occurring in and around the city of Murcia, Spain. Based on this research, this is the first integrated investigation of its type performed in Spain. The phenomenon of ground consolidation in the city of Murcia leads to the appearance of severe cracking and settlement in buildings. Subsidence is the result of two factors: on the one hand, the nature of the ground in this area, as it is made of recent deposits of clay and soft limes filled in with clay–lime backfills in the top layers. On the other hand, the increase in groundwater withdrawal during the 1992–95 drought led to a decrease in the water level of a magnitude never before recorded in the city. The risk prevention management suggested convenience of the installation of a measurement network to study and follow the phenomena of the subsidence to quantify it and to calibrate this theoretical model. This network is composed of extensometers and piezometers, the best devices to measure moderate ground movements, which is the case of Murcia. The first phase (Phase I) of this study of ground settlement in the metropolitan area of Murcia involved the installation of a network with 22 extensometers and taking the first measurement series. In a second phase (Phase II), during a period of 4 years, measurements with extensometers were performed to make the analysis and calibration of the theoretical model. Experience and data analysis showed the convenience of installation of new control points with an incremental extensometer and a piezometer in close position with the aim of precisely correlating piezometric levels with the observed subsidence. The third phase (Phase III) started in 2007, a new control technique, based on radar interferometry (InSAR), is being employed to provide information about subsidence in areas not previously monitored.  相似文献   
35.
In the Bariloche region, the Gondwanan basement consists of metamorphic and deformed igneous rocks intruded by Mesozoic and Tertiary granitoids. Metasediments and amphibolites have been affected by three main deformation events (D1, D2 and D3). D1 (S1 foliation) is well shown preserved in the microlithons of the S2 regional foliation and in albite and garnet porphyroblasts. Both foliations have been folded by upright open folds with associated crenulation (S3) locally developed in the D3 folds hinge zones. An early-stage (syn-D1) subduction episode can be invoked based on evidence of high pressure (HP) metamorphism in schists and amphibolites as well as on the presence of pre-collisional I-type granitoids. D2–D3 developed under regional intermediate pressure–low pressure (IP–LP) metamorphic conditions. High temperature (HT) conditions were reached, as deduced from regional migmatization and the intrusion of syn- to late-orogenic S-type granitoids. The transition from HP to IP metamorphic conditions could be associated with the emplacement of NE directed crustal-scale thrusts during D2.  相似文献   
36.
The Moa-Baracoa and Mayarí-Cristal massifs (eastern Cuba) are two ophiolitic complexes mainly constituted by harzburgite tectonites and minor dunites, cut by gabbroic dykes. The Moa-Baracoa massif exhibits a well developed Moho transition zone and an incomplete crustal section made up of layered gabbros and tectonically emplaced pillow basalts. A plutonic crustal section is absent in the Mayarí-Cristal massif and mantle tectonites are in tectonic contact with arc-related volcanic rocks. Mantle peridotites are very refractory in terms of modal composition, whole rock major element and HREE contents implying that Moa-Baracoa and Mayarí-Cristal harzburgites are residues after high degrees (20–30%) of partial melting. The relative enrichment of Th, Nb, Ta and LREE in peridotites is due to re-equilibration of melting residues with percolating melts. Peridotites lost on average 6 wt% of relative MgO by intense seafloor weathering. REE contents and Mg# of melts in equilibrium with cumulate gabbros from the Moho transition zone and crustal section of the Moa-Baracoa massif coincide with those of the spatially-related pillow basalts. On the other hand, no geochemical relation has been inferred between melt in equilibrium with Mayarí-Cristal segregate and the spatially-related arc volcanics. Our results indicate that the Mayarí-Baracoa Ophiolitic Belt formed at an original back-arc spreading centre. The Moa-Baracoa massif represents a portion of MORB-like lithosphere located nearby a back-arc mid-ocean spreading ridge, and the Mayarí-Cristal massif represents a piece of transitional (MORB to IAT) mantle located closer to the paleo-volcanic arc than Moa-Baracoa.  相似文献   
37.
After 2 years of operation onboard the Spanish satellite MINISAT, EURDhas achieved an unprecedented success in the observation of the terrestrialnightglow in the EUV, covering a range of 350-1100 Å EURD hasprovided a total of more than 543 hours ofintegration in the long wavelength spectrometer and more than898 hours in the short wavelength one, allowing the achievement of the most detailed atlas of the terrestrial EUV nightglow ever obtained. We present here the spectra obtained, together with the identification of the lines, some of themdetected for the first time in the nightglow. These spectrarepresent an improvement in sensitivity of several orders of magnitude with respect to previous observations. It has beenpossible, for the first time, to identify the complete Lymanseries of atomic hydrogen, resolving up to Lyman-. It hasalso been possible to identify the helium Lyman- line at 537 Å andto detect other lines of the blended Lyman series of helium, at 515 and522 Å. The spectra clearly show the presenceof the OII lines at 617, 644, 673, and 718 Å, previouslyobserved in the dayglow but seen here for the first time in thenightglow. In addition to the recombination continuum of the atomicoxygen at 911 Å, two features of OI have been detected in thenightglow: the 3s 3Do transition at 989 Å, previouslyobserved by Chakrabarti (1984) and the 2p34s3So transition at 1040 Å, partially overlapped with Lyman , but clearly distinguishable from it. This feature has been seen for the first timein the terrestrial nightglow. The radiative recombination continuum of atomic oxygen at 911 Å, that wasabsent in the observations of the first year of operation of EURD,is now clearly visible. The reasons of the absence of the OIfeature during the first year of operation are still unknown.Anderson et al. (1976) also noticed a strong variation with time of this 911 Å emission.  相似文献   
38.
The geological mapping of the Garonne Dome had already shown an angular unconformity between the Upper Ordovician and the underlying series. This paper presents data from a nearby location, Planelh deth Pas Estret, southeast of the Garonne Dome, where the unconformity can be seen at outcrop scale. The unconformity angles amount to up to 20°. This unconformity is interpreted as a result of an extensional event of pre-Upper Ordovician age. To cite this article: J. Garc??a-Sansegundo et al., C. R. Geoscience 336 (2004).  相似文献   
39.
A Smart City relies on six key factors: Smart Governance, Smart People, Smart Economy, Smart Environment, Smart Living and Smart Mobility. This paper focuses on Smart Mobility by improving one of its key components: positioning. We developed and deployed a novel indoor positioning system (IPS) that is combined with an outdoor positioning system to support seamless indoor and outdoor navigation and wayfinding. The positioning system is implemented as a service in our broader cartography-based smart university platform, called SmartUJI, which centralizes access to a diverse collection of campus information and provides basic and complex services for the Universitat Jaume I (Spain), which serves as surrogate of a small city. Using our IPS and based on the SmartUJI services, we developed, deployed and evaluated two end-user mobile applications: the SmartUJI APP that allows users to obtain map-based information about the different facilities of the campus, and the SmartUJI AR that allows users to interact with the campus through an augmented reality interface. Students, university staff and visitors who tested the applications reported their usefulness in locating university facilities and generally improving spatial orientation.  相似文献   
40.
The use of complex statistical models has recently increased substantially in the context of species distribution behavior. This complexity has made the inferential and predictive processes challenging to perform. The Bayesian approach has become a good option to deal with these models due to the ease with which prior information can be incorporated along with the fact that it provides a more realistic and accurate estimation of uncertainty. In this paper, we first review the sources of information and different approaches (frequentist and Bayesian) to model the distribution of a species. We also discuss the Integrated Nested Laplace approximation as a tool with which to obtain marginal posterior distributions of the parameters involved in these models. We finally discuss some important statistical issues that arise when researchers use species data: the presence of a temporal effect (presenting different spatial and spatio-temporal structures), preferential sampling, spatial misalignment, non-stationarity, imperfect detection, and the excess of zeros.  相似文献   
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