M. J. Marín

UV Index Experimental Values During the Years 2000 and 2001 from the Spanish Broadband UV-B Radiometric Network¶

Abstract An analysis is made of experimental ultraviolet erythemal solar radiation data measured during the years 2000 and 2001 by the Spanish UV-B radiation evaluation and prediction network. This network consists of 16 Robertson–Berger type pyranometers for evaluating solar erythemal radiation and five Brewer spectroradiometers for evaluating the stratospheric ozone. On the basis of these data the Ultraviolet Index (UVI) was evaluated for the measuring stations that are located either in coastal regions or in the more densely populated regions inland on the Iberian Peninsula. It has been checked that in most cases the maximum irradiance values corresponded to solar noon, although there were exceptions that could be explained by cloudiness. The maximum experimental values of the UVI were around 9 during the summer, though frequently passing this value at the inland measurement stations. The annual accumulated dose of irradiation on a horizontal plane has also been studied, as well as the evolution through the year in units of energy, standard erythemal doses and minimum erythemal doses, according to different phototypes.

Quantum fractal superlattices

Fractal superlattices consist of a series of thin layers of two semiconductor materials alternately deposited on each other with widths corresponding to the rules of construction of a fractal set. The scattering of electrons in superlattices is obtained using the transfer matrix method for generalized Cantor fractal potentials that are characterized by a lacunarity parameter. The numerical results show the self-similarity of the reflection coefficient and the appearance of lacunarity-independent energies with perfectly transparent tunneling due to the bound states of the particle in each of the individual potential wells.

A transfer matrix method for the analysis of fractal quantum potentials

The scattering properties of quantum particles on a sequence of potentials converging towards a fractal one are obtained by means of the transfer matrix method. The reflection coefficients for both the fractal potential and finite periodic potential are calculated and compared. It is shown that the reflection coefficient for the fractal potential has a self-similar structure associated with the fractal distribution of the potential whose degree of self-similarity has been quantified by means of the correlation function.

Ten years of measured UV Index from the Spanish UVB Radiometric Network.

An analysis is made of the UV Index (UVI) obtained from the ultraviolet erythemal solar radiation (UVER) data measured by the Spanish UVB Radiometric Network between the years 2000 and 2009. Previously, the daily UVI has been evaluated using two different criteria: (a) the value corresponding to solar noon; and (b) the daily maximum value. The mean percentage of agreement is 92% if we consider the cases for which the difference is zero or one UVI unit. These results are similar to those obtained in a previous work where only 2 years were analyzed. In all the stations the UVI reaches very high values (8-10) in spring-summer, and the very high and extreme (≥ 11) UVI values are more dependent on the continental effect than on the latitude effect. From the UVI values it is possible to classify the stations into four groups: Coastal stations, Continental stations (more than 200 km from the coast), Southern stations (Coastal stations but with similar values of UVI as the Continental ones due to their low latitude) and Canary Islands stations (1400 km southwest from the Iberian Peninsula thus lower latitude). The monthly mean maximum of UVI is reached in July due to the annual evolution of the total ozone column. This value corresponds, for a skin phototype II, to three times the minimal erythemal dose (MED) in an hour in a Coastal station, 3.5 MEDs in an hour measured in a Continental or Southern station and up five MEDs in an hour in the Izaña station (Canary Islands). The cumulative dose on a horizontal plane over an average year has been calculated for each station. More than 40% of the annual dose is received in summer, about 35% in spring, more than 11% in autumn and less than 10% in winter except for the stations in the Canary Islands where the difference between seasons is less significant.

Diffuse Ultraviolet Erythemal Irradiance on Inclined Planes: A Comparison of Experimental and Modeled Data

Values of measured and modeled diffuse UV erythemal irradiance (UVER) for all sky conditions are compared on planes inclined at 40° and oriented north, south, east and west. The models used for simulating diffuse UVER are of the geometric‐type, mainly the Isotropic, Klucher, Hay, Muneer, Reindl and Schauberger models. To analyze the precision of the models, some statistical estimators were used such as root mean square deviation, mean absolute deviation and mean bias deviation. It was seen that all the analyzed models reproduce adequately the diffuse UVER on the south‐facing plane, with greater discrepancies for the other inclined planes. When the models are applied to cloud‐free conditions, the errors obtained are higher because the anisotropy of the sky dome acquires more importance and the models do not provide the estimation of diffuse UVER accurately.

UV Index on Tilted Surfaces

Abstract Solar ultraviolet erythemal irradiance (UVER) has been studied on inclined planes with different orientations in Valencia, Spain. To do this a platform was designed that could turn through 90° on its own axis. The radiometers were inclined at an angle close to the latitude of Valencia (39.5° N). Using two timers the platform could be turned through 90° every 5 min. On clear or partially cloudy days, including those with different turbidity values, it was observed that the UVER showed a maximum at 1200 h GMT, very close to solar noon, in the north and south positions, while the maximum for east and west orientations was found at approximately one hour before and one hour after midday respectively. It was also observed how the irradiance for the south orientation was greater and for the north was less than for the horizontal plane, as well as the opposite performances of the east and west orientations, for four days close to the summer and winter solstices and each equinox. Some experimental results were also compared with the results from the SMARTS2.9 model for the same conditions. It was found that the model frequently overestimated the experimental data. With respect to the maximum calculated UV Index in the different planes this was always higher for the south orientation than for the north, while it was similar for east and west orientations throughout the year. Finally the accumulated erythemal dosage for the considered period was obtained as a function of phototype and orientation, confirming that the accumulated erythemal dosage decreased by around 37% in the north orientation compared to the horizontal value, while in the south position it was only 6% less and some 20% and 15% less in the east and west positions, respectively.

Selecting Microbial Strains from Pine Tree Resin: Biotechnological Applications from a Terpene World

Resin is a chemical and physical defensive barrier secreted by many plants, especially coniferous trees, with insecticidal and antimicrobial properties. The degradation of terpenes, the main components accounting for the toxicity of resin, is highly relevant for a vast range of biotechnological processes, including bioremediation. In the present work, we used a resin-based selective medium in order to study the resin-tolerant microbial communities associated with the galls formed by the moth Retinia resinella; as well as resin from Pinus sylvestris forests, one of the largest ecosystems on Earth and a yet-unexplored source of terpene-degrading microorganisms. The taxonomic and functional diversity of the cultivated, resin-tolerant fraction of the whole microbiota were unveiled by high-throughput sequencing, which resulted in the detection of more than 40 bacterial genera among the terpene-degrading microorganisms, and a range of genes involved in the degradation of different terpene families. We further characterized through culture-based approaches and transcriptome sequencing selected microbial strains, including Pseudomonas sp., the most abundant species in both environmental resin and R. resinella resin-rich galls, and three fungal species, and experimentally confirmed their ability to degrade resin and also other terpene-based compounds and, thus, their potential use in biotechnological applications involving terpene catabolism.

UVER and UV index at high altitude in Northwestern Argentina

Measurements of ultraviolet erythemal radiation (UVER) made during two years at three sites located at altitudes over 1000ma.s.l. in Northwestern Argentina (Salta, San Carlos, and El Rosal) have been used to estimate and analyze the UV Index (UVI) and the cumulative doses at these locations. For the UVER irradiance, data of January (maximum values) and June (minimum values) have been analyzed as representative of the year for all locations. The UVI reaches extreme (>11) values in >20% of the analyzed days in Salta (1190ma.s.l.), while these are reached in San Carlos (1611ma.s.l.) and El Rosal (3355ma.s.l.) in >40% of the analyzed days. Finally, the cumulative doses over an average year have also been studied for each location. The doses received during austral summer and autumn are of the same order, and represent one third of the annual dose, while the doses received during austral winter and spring represent one sixth of the annual dose approximately.

Sensitivity of UVER enhancement to broken liquid water clouds: A Monte Carlo approach

The study uses a Monte Carlo radiative transfer model to examine the sensitivity of the UV erythemal radiation (UVER) enhancement to broken liquid water clouds of the cumulus and stratocumulus type. The model uses monochromatic radiation at 310 nm corresponding approximately to the peak of the product between irradiance and the erythemal curve. All scattering, absorption, extinction coefficients, and spectral albedos are tuned to this wavelength. In order of importance, fractional cloud cover, the area of individual cloud patches, and cloud thickness exert a strong influence on the enhancement, with smaller contributions from cloud optical depth, cloud base height, and solar zenith angle. In order to produce realistic enhancements for our study area located in the Valencia region of Spain (39°30′N, 0°25′W), measurements were obtained from a Landsat image of the region in combination with a spectral Fourier transform model. The Monte Carlo model, as applied to the Fourier transform cloud distribution, produced satisfactory results compared to 1 year of measured UVER enhancement for the study region provided that fractional cloud cover was equal to or greater than 3/10. At smaller cloud fractions, the neglect of cloud patches less than 50 m × 50 m in area by the model created significant discrepancies.

UVB and erythemal solar radiation on tilted planes in Valencia, Spain

A preliminary analysis of experimental UVB and erythemal solar radiation data measured in Valencia a Mediterranean coastal site in Spain, is made. The data have been recorded by means of four broadband radiometers YES UVB-1 recently installed by the Solar Radiation Group of the University of Valencia. One of them measures global horizontal irradiance. The second one has a shadowband for the measurement of diffuse horizontal irradiance. The other two instruments record global irradiance data on planes inclined 45° alternating North-South and East-West orientation. The results show some differences between UVB irradiation on horizontal and tilted surfaces and also among the different orientations. The irradiance received in horizontal position is higher than on the others planes and the daily maximum value is reached at noon in horizontal, North and South positions whereas on East plane it happens before the noon and after the noon in West orientation. This kind of measurements allows the evaluation of the UV Index corresponding to solar radiation on tilted surfaces with different azimutal angles. The differences between horizontal UV Index and North UV Index are of three units. In contrast on the South is of one unit at the most.