Interplay of orbital forcing and tectonic pulses in the Cambrian Iberian platform, NE Spain

The stratigraphy of carbonate/shale couplets, cycles and cycle-stacking patterns in a Cambrian shallow water platform (Iberian Chains, NE Spain) are related to sea-level changes driven by orbital forcing and by tectonic pulses. The interplay of both effects can be discriminated in the Iberian fault-controlled platform, in which the tectonic activity can be analysed by accurate and detailed biostratigraphic correlations based on trilobite zonation. The stratigraphic hierarchy of rhythmically interbedded limestones and shales, in two coeval but structurally separated geodynamic settings, yields cycle ratios of 1.44 :1. This ratio is supported by time thickness and spectral analysis, which is based on a graphic method of analysis: the Map of Grey Lines. The cycle ratio seems to be evidence for orbital forcing by obliquity and precession cycles predicted for early Paleozoic time. Carbonate/shale couplets, the smallest rhythmic units recognisable in the field, represent short-term, periodic fluctuations in supply of terrigenous sediments and carbonate productivity of uncertain origin, which could be associated with one of several harmonics of the former orbital cycles. The pulsating tectonic activity was approximated by using a quantitative analysis of tectonically induced subsidence (Shaw method). Recurrence frequencies of tectonic pulses were estimated and dated by biostratigraphy. As a result, tectonic disturbances in the Cambrian Iberian platform show an episodic periodicity comparable to that of orbital eccentricity cycles, which could mask their recognition. Received: 15 November 1999 / Accepted: 9 February 2000     

Preliminary Analysis of V and Hp Light Curves of 26 Carbon Miras

Light variations of a representative sample of 26 more or less periodically variable carbon stars were analyzed on the basis of 2220 individual observations made by the Hipparcos satellite and 33 544 visual observations listed in AFOEV and VSOLJ databases within the interval JD = 2 448 000 (1988) ±6 cycles. We found the osculating linear ephemerides of all stars and their mean light curves, as well. We found that the light curves of the carbon Miras in our set can be satisfactorily expressed as a linear combination of only two basic light curves. The analysis was done by an own method combining robust regression and principal component analysis.     

An analysis of surges triggered by a small flare

On 22 October, 1980, near the solar central meridian in the western vicinity of a large spot group, a subflare of the two-ribbon type was observed. Three surges were associated with this flare. Their starting points were situated close to the principal flare patches on both sides of a short filament that was visible for only a few hours. True flow velocities and decelerations along the arch-shaped surge trajectories have been determined for two of the surges. The highest velocities were found at the onset of the surges.The event was studied from a series of H on- and off-band flltergrams taken with the Debrecen coronagraph of 53 cm aperture.     

Multi-temporal assessment of vulnerability to climate change: insights from the agricultural sector in Mexico

Vulnerability to climate change was evaluated for three different time periods: 1990, 2000, and 2010. Our objective was to discuss the scope of a multi-temporal assessment of vulnerability. The method used 55 indicators—with emphasis on the agricultural sector in Mexico—of which 27 were updated for the year 2010 and 33 were retrospectively estimated for the year 1990. The results show that in the 20-year study period, the exposure of the municipalities (and inhabitants) has increased, and sensitivity and adaptive capacity have decreased. The number of municipalities vulnerable to climate change declined over the 20-year period. We found that calculating vulnerability by adding exposure and sensitivity and subtracting adaptive capacity (E?+?S???AC) can lead to unintentional underestimation of total vulnerability. When rating vulnerability, care must be taken in what is reported: the results differ for the number of inhabitants versus the number of municipalities. Our previous published vulnerability evaluation was for the year 2000, so we wanted to evaluate the sensitivity of some variables and the vulnerability formula itself we used in that moment. It is possible to evaluate the vulnerability multi-temporally, which allows to evaluate the sensibility and calibration of the variables and indicators used and the reconsideration of their application.     

Biogeographical drivers of ragweed pollen concentrations in Europe

Theoretical and Applied Climatology - The drivers of spatial variation in ragweed pollen concentrations, contributing to severe allergic rhinitis and asthma, are poorly quantified. We analysed the...     

Climatic constraints for the maize-soybean system in the humid subtropical region of Argentina

The implementation of two summer crops in the same growing season is a possible alternative for land intensification in areas with a long frost-free period. The aim of this study was to analyse the strategy of land intensification through the implementation of the maize-soybean succession at two locations (Reconquista, 29°09′S 59°40′W and Las Breñas, 27°05′S 61°5′W) of the humid subtropical region of Argentina. CERES-Maize and CROPGRO-Soybean models were used to evaluate the impact of inter-annual variability of climate (36 years) of both locations on rain-fed grain yields of the following productive alternatives: (i) monoculture of maize, (ii) monoculture of soybean and (iii) the succession of a short-cycle maize followed by soybean as the second summer crop (maize-soybean system). The maize-soybean system was evaluated by the method of land equivalent ratio (LER), based on the sum of the relative grain yields of its components. The impact of the inter-annual variability of climate and of “El Niño” or “La Niña” episodes (El Niño Southern Oscillation phenomenon (ENSO)) on LER values was analysed. Simulated yields of maize monoculture (5687 kg ha^?1; CV = 49.7% and 5637 kg ha^?1; CV = 57.6% at Reconquista and Las Breñas, respectively) were higher than those of the short-cycle maize, especially at Las Breñas (5448 kg ha^?1; CV = 49.3% and 2322 kg ha^?1; CV = 33.9% at Reconquista and Las Breñas, respectively). Simulated yields of the soybean monoculture were higher (3588 kg ha^?1; CV = 26.1% and 2883 kg ha^?1; CV = 20.7% at Reconquista and Las Breñas, respectively) that those of the soybean as the second crop (2634 kg ha^?1; CV = 38.1% and 2456 kg ha^?1; CV = 32.9% at Reconquista and Las Breñas, respectively) at both locations. Average LERs were 1.69 (CV = 11.4%) at Reconquista and 1.41 (CV = 26.1%) at Las Breñas, and the inter-annual variability of LER was mainly determined by grain yields of (i) soybean as the second crop at Reconquista and (ii) maize monoculture at Las Breñas. Soil water content after maize harvest and rainfalls during reproductive period of soybean as the second crop conditioned LER values, but they were generally greater than 1. At Reconquista, LER values were not affected by the different episodes of ENSO phenomenon. By contrast, at Las Breñas, LER values were higher during La Niña episodes (1.48; CV = 26.6%) than during El Niño episodes (1.32; CV = 23.7%) mainly by their effects on grain yields of maize monoculture. Therefore, crop simulation models demonstrate the possibility to intensify land use (40–70%) at two locations of the humid subtropical region of Argentina, by the implementation of the maize-soybean system.     

Testing spatial heterogeneity in geographically weighted principal components analysis

We propose a method to evaluate the existence of spatial variability in the covariance structure in a geographically weighted principal components analysis (GWPCA). The method, that is extensive to locally weighted principal components analysis, is based on performing a statistical hypothesis test using the eigenvectors of the PCA scores covariance matrix. The application of the method to simulated data shows that it has a greater statistical power than the current statistical test that uses the eigenvalues of the raw data covariance matrix. Finally, the method was applied to a real problem whose objective is to find spatial distribution patterns in a set of soil pollutants. The results show the utility of GWPCA versus PCA.     

Galileo Constellation Design

A significant effort has been carried out in Europe to define the European Global Navigation Satellite System (GNSS), named Galileo Satellites flying in Medium Earth Orbits (MEO) will compose the system (according to the most recent architecture definition baseline); a regional complement of geosynchronous satellites may be required to increase performances over Europe and maybe also to provide some specific communication services. Nominal medium performances are envisaged, but they will be increased by means of augmentation systems (local or wide area), or even by using simultaneously other GNSSs such as GPS. All the involved requirements make the design process quite complex. A powerful software tool, Elcano, has been developed for this purpose; its capabilities will be outlined, and the results of the design process will be presented. ? 2001 John Wiley & Sons, Inc.     

Timing of low-temperature metamorphism and cooling of the Paleozoic and Mesozoic formations of the Bükkium,innermost Western Carpathians,Hungary

K-Ar ages of illite-muscovite and fission track ages of zircon and apatite were determined from various lithotypes of the Bükkium, which forms the innermost segment of the Western Carpathians. The stratigraphic ages of these Dinaric type formations cover a wide range from the Late Ordovician up to the Late Jurassic. The grade of the orogenic dynamo-thermal metamorphism varies from the late diagenetic zone through the anchizone up to the epizone (chlorite, maximally biotite isograd of the greenschist facies). The K-Ar system of the illite-muscovite in the < 2 m grain-size fraction approached equilibrium only in epizonal and high-temperature anchizonal conditions. The orogenic metamorphism culminated between the eo-Hellenic (160-120 Ma) phase connected to the beginning of the subduction in the Dinarides, and the Austrian (100-95 Ma) phase characterized by compressional crustal thickening. No isotope geochronological evidence was found for proving any Hercynian recrystallization. The stability field of fission tracks in zircon was approached using the thermal histories of the different tectonic units. A temperature less than 250°C and effective heating time of 20–30 Ma had only negligible effects on the tracks, whereas total annealing was reached between 250 and 300°C. Apatite fission track ages from the Paleozoic and Mesozoic formations show that the uplift of the Bükk Mountains occurred only in the Tertiary (not earlier than ca. 40 Ma ago). Thermal modeling based on apatite fission track length spectra and preserved Paleogene sediment thickness data proved that the Late Neogene burial of the recently exhumed plateau of the Bükk Mountains exceeded 1 km.     

Green areas and water management in residential developments in the European Western Mediterranean. A case study of Alicante,Spain

The intense urbanization of the Mediterranean coast as a result of the development of residential-tourist activities since the 1960s, especially from the mid-1990s to 2008, has generated new urban environments associated with extensive urban typologies. These include gardens linked to houses with outdoor spaces that are shared between all of the residents of the residential developments. The aim of this study is to determine the main characteristics of these new urban green spaces and their effect on domestic water consumption in Alicante (Spain). To do this, we analysed the characteristics that define these types of gardens (surface area, density, plant species and irrigation system) and determined their water needs using the Water Use Classifications of Landscape Species method. The main conclusions are that the increase in paved areas is one of the strategies to reduce water consumption in spaces where turf grass is the most common plant species. This is due to increased water prices and lack of water resources.