The Canary Eddy Corridor: A major pathway for long-lived eddies in the subtropical North Atlantic

We report, from remote sensing and in situ observations, a new type of permanent structure in the eastern subtropical Atlantic Ocean, that we call the “Canary Eddy Corridor”. The phenomenon, is a zonal long-lived (>3 months) mesoscale eddy corridor, whose source is the flow perturbation of the Canary Current and the Trade Winds at the Canary Islands. The latitudinal range of the corridor spans 22°N–29°N and extends from the Canaries to at least 32ºW, near the mid-Atlantic. This is the main region of long-lived westward-propagating eddies in the subtropical northeast Atlantic. From a age-distribution study we observe that at least 10% of mesoscale eddies in this region are long-lived, with a dominance of anticyclones over cyclones. Another four westward-propagating eddy corridors were also detected: two small corridors north and south of the Azores Front; a small zonal corridor located near 31ºN, south of the island of Madeira; and a small corridor located near the Cape Blanc giant filament. The existence of these corridors may change, at least for the northeastern subtropical Atlantic, the general idea that mesoscale eddies are disorganized, ubiquitous structures in the ocean. The Canary Eddy Corridor constitutes a direct zonal pathway that conveys water mass- and biogeochemical properties offshore from the Canary Island/Northwest Africa upwelling system, and may be seen as a recurrent offshore pump of organic matter and carbon to the oligotrophic ocean interior. Estimates of volume and mass transport indicate that Canary Eddy Corridor westward transport is more than one-fourth of the southward transport of the Canary Current. The westward transport of kinetic energy by the eddies of the Canary Corridor is as important as the southward transport by the Canary Current. The total primary production related to the Corridor may be as high as the total primary production of the northwest Africa upwelling system for the same latitude range.     

Geothermal effects in the formation of electrically conducting zones and temperature distribution in the earth

Pollack and Chapman have shown that the surface heat flow in continental regions is dependent not only on the earth's crust below the observation site, but also on the upper mantle there. Therefore heat flow can be used to investigate the role of the thermal conditions in the creation of the electrically conductive zones in both the crust and mantle.Empirical exponential formulas describe the depth to the conductivity increase in the crust corresponding to granitization, the depth to the conductive zone at the top of the asthenosphere (SLVZ), as a function of heat flow. Comparing the latter with temperature estimations in the asthenosphere it is concluded that partial melting of the upper mantle occurs only where $\text{q ? 42}\text{m W m}{}^{\mathrm{?2}}\text{? 1}\text{HFU}$.The depth to the conductivity increase corresponding to the mineralogic phase transition in the upper mantle is increased with high temperatures. Such a conductive zone shows that the maximum temperature difference between stable platform areas and active zones is about 1000°C.     

Ein impulsoptisches Transmissometer für Registrierung der Normsichtweite zwischen etwa 40m und ∞ (Videograph)

Zusammenfassung Das impulsoptische Signalübertragungsprinzip mit Funkenlicht als Sender und einem photoelektrischen Impulsempfänger wurde als Transmissometer ausgeführt. Mittels unterkritischem Betrieb der Funkenstrecke unterliegt der Sender keinen störenden Intensitätsschwankungen. Der Meßbereich der Extinktion beträgt 110⁵, entsprechend etwa 40 m bis Normsichtweite. Das Gerät ist klimafest für Flugplatzbelange ausgebildet und benötigt zum Schreiber hin nur Telephonkabel.

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Summary A transmission-measuring apparatus was constructed on the principle of transmitting impulse-optic signals by means of spark light as transmitter and a photo-electric cell as impulse receiver. The transmitter shows no disturbing variations of intensity if the spark gap is operated under the critical value. The measuring range of extinction amounts to 110⁵ corresponding to a normal range of visibility from about 40 m to infinite. The apparatus is designed for airports. A simple telephon cable serves as conection with the recording system.

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Résumé Le procédé à impulsions lumineuses reçues par une cellule photoélectrique a été developpé sous forme d'appareil à transmission. L'emeteur fonctionnant sous longueur sous-critique des étincelles n'éprouve pas de variations gênantes d'intensité. Le domaine de mesure de l'extinction est de 110⁵, correspondant à une portée comprise entre 40 m. et l'infini. L'appareil, à l'abri des intempéries, se prête à l'emploi sur les aérodromes; la liaison avec l'enregistreur se fait à l'aide d'un simple câble téléphonique.

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Mit 6 Textabbildungen     

Solar-Blind Diamond Detectors for Lyra, the Solar VUV Radiometer on Board Proba II

Fabrication, packaging and experimental results on the calibration of metal-semiconductor-metal (MSM) photodetectors made on diamond are reported. LYRA (Lyman- RAdiometer onboard PROBA-2) will use diamond detectors for the first time in space for a solar physics instrument. A set of measurement campaigns was designed to obtain the XUV-to-VIS responsivity of the devices and other characterizations. The measurements of responsivity in EUV and VUV spectral ranges (40–240 nm) have been carried out by the Physkalisch-Technische Bundesanstalt (PTB) in Germany at the electron storage ring BESSY II. The longer wavelength range from 210 to 1127 nm was measured with monochromatic light by using a Xe-lamp at IMO-IMOMEC. The diamond detectors exhibit a photoresponse which lie in the 35–65 mA/W range at 200 nm (corresponding to an external quantum efficiency of 20–40%) and indicate a visible rejection ratio (200–500 nm) higher than four orders of magnitude.     

A Comparative Analysis of Transpiration and Bare Soil Evaporation

Transpiration E^v and bare soil evaporation E^b processes are comparatively analysed assuming homogeneous and inhomogeneous areal distributions of volumetric soil moisture content . For a homogeneous areal distribution of we use a deterministic model, while for inhomogeneous distributions a statistical-deterministic diagnostic surface energy balance model is applied. The areal variations of are simulated by Monte-Carlo runs assuming normal distributions of .The numerical experiments are performed for loam. In the experiments we used different parameterizations for vegetation and bare soil surface resistances and strong atmospheric forcing. According to the results theE^v()-^Eb() differences are great, especially in dry conditions. In spite of this, the available energy flux curves of vegetation A^v() and bare soil A^b() surfaces differ much less than the E^v() and ^Eb() curves. The results suggest that E^v is much more non-linearly related to environmental conditions than ^Eb. Both E^v and ^Eb depend on the distribution of , the wetness regime and the parameterization used. With the parameterizations, ^Eb showed greater variations than E^v. These results are valid when there are no advective effects or mesoscale circulation patterns and the stratification is unstable.     

A record of pre-Variscan Barrovian regional metamorphism in the eastern part of the Slavonian Mountains (NE Croatia)

Summary Petrological investigations and monazite dating are carried out on medium-grade metamorphic rocks (micaschist, gneiss and amphibolite) from the Kutjevačka Rijeka transect in the Slavonian Mts., Tisia Unit (NE Croatia). Field, mesoscopic and microstructural observations, as well as the preserved mineral chemistry, point to a single metamorphic event during peak assemblage growth reaching amphibolite facies conditions of ca. 600–650 °C and 8–11 kbar. Th, U and Pb contents of yttrium-rich accessory monazites indicate a pre-Variscan, i.e. Ordovician-Silurian age (444 ± 19 and 428 ± 25 Ma) for the medium-grade metamorphism of garnet-bearing micaschist.     

Petrology of a new basalt occurrence in Hungary

Summary A new occurrence of basalt (minimum K/Ar age 57.9 ± 2.2 m.y.) is reported from Budaliget, near Budapest. Major and minor element concentrations show that the basalts are alkaline and potassic in nature ranging from olivine tholeiite to moderately undersaturated basanite. High mg-values and concentrations of Ni and Cr indicate that some of the samples may represent primary compositions. High pressure accidental xenoliths, xenocrysts and cognate megacrysts are frequent and the chemical zoning patterns of olivine and pyroxene phenocrysts indicate a complex evolution and polibaric conditions for the crystallization. The discovery of the new basalt occurrence is important from a geodynamical point of view: prior to the last two major geodynamical events (Plio-Pleistocene rifting with associated alkali basaltic volcanism and collision of microplates with associated Miocene calk-alkaline volcanism) the continental lithosphere below NE Transdanubia may have experienced another rifting period in the Paleocene or Upper Cretaceous.With 7 Figures     

FRACTURES AS CONDUCTING DYKES AND CORRESPONDING TWO-DIMENSIONAL MODELS*

A statistical treatment of MT data from the Pannonian Basin, Hungary, based on the distortion theory of the S-effect suggests that the local increase in crustal conductivity is connected with deep fractures. Field model measurements have recently been carried out in a shallow, quasi two-dimensional basin of well known tectonics using MT station distances of 1–3 km. The results of the investigation and numerical modelling of near surface distortions, support the idea that deep fractures (faults) contain the conducting formations. According to 2-D model computations, several conducting dykes at considerable depths can cause anomalies which are indiscernible from an anomaly due to a conducting layer. The significance of these results is discussed from the point of view of geothermal energy exploitation.