Variations of solar EUV,UV and ionospheric foF2 related to the solar rotation period

Spectral analysis of daily values of various solar indices viz. sunspot number, 10.7-cm flux, H Lyman-<alpha> and -<beta>, specific He, Fe and Mg lines and solar X-rays was carried out for two selected intervals. During interval A (May-August 1978, 123 days) the solar indices showed a prominent periodicity near 27 days, while during interval B (January-May 1979, 151 days) the solar indices showed a prominent periodicity near 13 days. For the same intervals, foF2 (max) and foF2 (average) during 1000–1500 LT were similarly analysed for the locations Cachoeira Paulista, SP, Brazil (23○S, 45○W), and Okinawa (26○N, 128○E) and Kokubunji (36○N, 139○E) in Japan. The 27-day and 13-day periodicities in solar indices were reflected in the foF2 series, but in different relative proportions at the three locations, probably due to the interference of local aerodynamical effects. Some other periodicities were common to solar indices and foF2, while some others were present in the solar indices but not in foF2, or vice versa.     

Regional variability in relationships between climate and dengue/DHF in Indonesia

Since 1970, the worldwide distribution, frequency and intensity of epidemics of dengue and dengue haemorrhagic fever (DHF) have increased dramatically. In Indonesia, as elsewhere, the geographic distribution and behaviour of the two main vectors – Aedes aegypti and Aedes albopictus – and the consequent transmission dynamics of the disease are strongly influenced by climate. Monthly incidence data were examined in relation to monthly data for temperature, rainfall, rainfall anomalies, humidity and the Southern Oscillation Index for 1992–2001. Focusing on eight provinces, significant Pearson correlations were observed between dengue/DHF incidence and at least one climate variable ( r  = ±0.2 to ±0.43; P  < 0.05). Multiple regression analyses showed that 12.9–24.5 per cent of variance in incidence was explained by two or three climate variables in each province ( P  < 0.1–0.01). Rainfall appears to be the principal climatic agent affecting the geographic distribution and temporal pattern of incidence while temperature appears to play a critical role in outbreak intensity. Wide regional and temporal variations in the strength and nature of the observed associations led to the identification of three groups of provinces where increases in dengue/DHF incidence were variously associated with increased rainfall, decreased rainfall and/or high susceptibility to climate variability. Although climatic factors play an important role in explaining the timing and intensity of dengue/DHF outbreaks, a wide range of other factors specific to local environments also appear to be involved – information that may assist in the prediction and mitigation of regional dengue/DHF outbreaks.     

Preliminary Map of Soil's Predominant Periods in Barcelona Using Microtremors

—?In order to evaluate soil effects in the urban area of Barcelona, the Nakamura's technique has been used to estimate the predominant periods of soils. Noise measurements for 195 sites were performed using a strong motion accelerograph and a velocimeter. In this work, the resulting preliminary map of predominant periods is presented. The obtained predominant periods are coherent with the geological and geotechnical features of the area. The analysis of the information has allowed the distinctions among several types of soil and underlying materials. A predominant period of about 0.06?s is evaluated for sites located over outcrop Paleozoic rock in the Tibidabo-Collserola Mountains. For sites consisting of material named tricycle, that is the most extensive and also the most heterogeneous zone, predominant period range from 0.10?s up to 2.0?s depending on the thickness of the surface materials and the kind and thickness of the underlying materials. In the Besós river two zones are observed: the riverside with periods between 0.50?s and 0.83?s and a second area with periods between 1.0 and 2.1?s. In the Llobregat river delta the obtained periods are quite homogeneous with values around 0.72?s. Other predominant periods are found in some tertiary rock outcrop.     

The aegean sea oil spill in the Galicia Coast (NW Spain). I. Distribution and fate of the crude oil and combustion products in subtidal sediments.

The spatial distribution and fate of petrogenic and pyrogenic hydrocarbons in coastal sediments following the Aegean Sea oil spill (Galicia, NW Spain) was investigated through a detailed study of chemical markers. Alkanes and acyclic isoprenoid hydrocarbons were degraded within six months of the accident, but triterpane and sterane distributions were still detectable and were useful in monitoring, respectively, the oil source and weathering. Aromatic steranes were also useful source indicators, and oil degradation was clear from the decrease of certain alkyl dibenzothiophene and phenanthrene isomers. The pyrogenic polycyclic aromatic hydrocarbons produced in the tanker wreck were found more persistent than the petrogenic ones. However, the presence of the oil in the sediments was recognized even one year after the accident and was found particularly preserved in the subsurface layers.     

Two Brazilian archaeological sites investigated by GPR: Serrano and Morro Grande

The application of the ground penetrating radar (GPR) at two archaeological sites, Serrano and Morro Grande, situated in Araruama County, Rio de Janeiro, Brazil, aids the study of a prehistoric indigenous culture, associated with the “Tupinambá” that inhabited the region during prehistoric times.The archaeological remains of the study area are mainly characterized by pottery artifacts for several uses, including funerary urns, which were buried within layers of sand and clay. Several profiles were acquired using a RAMAC system, with a 200 and 400 MHz frequency antennae. At the Serrano site, the profiles were acquired around some partially exposed pottery shards, due to sand exploitation. The resultant profiles provided a response model to guide the interpretation of new profiles acquired at other sites in the area, which present similar characteristics.The results showed the great importance of the dielectric permittivity contrast which exists between the targets and the host media, in order for possibly significant features to be identified in radar data.     

Combining European Earth Observation products with Dynamic Global Vegetation Models for estimating Essential Biodiversity Variables

ABSTRACT

Global, fast and accessible monitoring of biodiversity is one of the main pillars of the efforts undertaken in order to revert it loss. The Group on Earth Observations Biodiversity Observation Network (GEO-BON) provided an expert-based definition of the biological properties that should be monitored, the Essential Biodiversity Variables (EBVs). Initiatives to provide indicators for EBVs rely on global, freely available remote sensing (RS) products in combination with empirical models and field data, and are invaluable for decision making. In this study, we provide alternatives for the expansion and improvement of the EBV indicators, by suggesting current and future data from the European Space Agencýs COPERNICUS and explore the potential of RS-integrated Dynamic Global Vegetation Models (DGVMs) for the estimation of EBVs. Our review found that mainly due to the inclusion of the Sentinel constellation, Copernicus products have similar or superior potential for EBV indicator estimation in relation to their NASA counterparts. DGVMs simulate the ecosystem level EBVs (ecosystem function and structure), and when integrated with remote sensing data have great potential to not only offer improved estimation of current states but to provide projection of ecosystem impacts. We suggest that focus on producing EBV relevant outputs should be a priority within the research community, to support biodiversity preservation efforts.     

Geostatistics and Bayesian updating for transmissivity estimation in a multiaquifer system in Manitoba,Canada

In ground water flow and transport modeling, the heterogeneous nature of porous media has a considerable effect on the resulting flow and solute transport. Some method of generating the heterogeneous field from a limited dataset of uncertain measurements is required. Bayesian updating is one method that interpolates from an uncertain dataset using the statistics of the underlying probability distribution function. In this paper, Bayesian updating was used to determine the heterogeneous natural log transmissivity field for a carbonate and a sandstone aquifer in southern Manitoba. It was determined that the transmissivity in m²/sec followed a natural log normal distribution for both aquifers with a mean of -7.2 and - 8.0 for the carbonate and sandstone aquifers, respectively. The variograms were calculated using an estimator developed by Li and Lake (1994). Fractal nature was not evident in the variogram from either aquifer. The Bayesian updating heterogeneous field provided good results even in cases where little data was available. A large transmissivity zone in the sandstone aquifer was created by the Bayesian procedure, which is not a reflection of any deterministic consideration, but is a natural outcome of updating a prior probability distribution function with observations. The statistical model returns a result that is very reasonable; that is homogeneous in regions where little or no information is available to alter an initial state. No long range correlation trends or fractal behavior of the log-transmissivity field was observed in either aquifer over a distance of about 300 km.     

Coda Q before and after the eruptions of 13 November 1985, and 1 September 1989, at Nevado del Ruiz Volcano, Colombia

 Coda Q^–1 was calculated at Nevado del Ruiz Volcano (NRV) before and after two phreatomagmatic eruptions (November 1985, September 1989) and for a period of stability (May 1987) using a functional form for coda derived from a single scattering model (Sato 1977). Substantial changes were found before and after the eruptions. The highest value of Q^–1 was found during the November 1985 eruption, an intermediate value for the September 1989 eruption, and the lowest value for May 1987. It seems that the changes in coda Q^–1 at NRV have a still-unknown relationship with the volume or magnitude of the eruption. A relatively strong frequency dependence was found for all periods. Also Q^–1 clearly changed with time, suggesting that the scattering was strong for the eruption of November 1985 and decreased for the eruption of September 1989, and that the intrinsic absorption probably increased. This suggests the possibility that crystallization is taking place in the NRV magma. The clear change of coda Q^–1 before and after the eruptions at NRV also suggests the possibility that coda Q^–1 is a premonitory tool of activity at this volcano. Received: 25 October 1996 / Accepted: 21 January 1998     

A Method for Obtaining the Nuclear Component in Active Galaxies

We present a new method for the obtention of the nuclear component of active galatic nuclei, that relies on the convolution of a two-dimensional model of the host galaxy, based on seeing-free morphological parameters, with the seeing PSF. The procedure overcomes some limitations of the methods currently in use and does not assume that the nucleus is unresolved. This revised version was published online in July 2006 with corrections to the Cover Date.