981 resultados para Mediterranean and Black Seas


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The sea state of the Beaufort and Chukchi seas is controlled by the wind forcing and the amount of ice-free water available to generate surface waves. Clear trends in the annual duration of the open water season and in the extent of the seasonal sea ice minimum suggest that the sea state should be increasing, independent of changes in the wind forcing. Wave model hindcasts from four selected years spanning recent conditions are consistent with this expectation. In particular, larger waves are more common in years with less summer sea ice and/or a longer open water season, and peak wave periods are generally longer. The increase in wave energy may affect both the coastal zones and the remaining summer ice pack, as well as delay the autumn ice-edge advance. However, trends in the amount of wave energy impinging on the ice-edge are inconclusive, and the associated processes, especially in the autumn period of new ice formation, have yet to be well-described by in situ observations. There is an implicit trend and evidence for increasing wave energy along the coast of northern Alaska, and this coastal signal is corroborated by satellite altimeter estimates of wave energy.

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Dissertação de dout. em Ecologia, Faculdade de Ciências do Mar e do Ambiente, Univ. do Algarve, 2005

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Galeus atlanticus is a small-sized deepwater catshark living on the slope bottom of the Alborán Sea. Given its external similarities with Galeus melastomus, both species are often confused, which makes G. atlanticus a very poorly understood species both in terms of catches and biological aspects. For this study, a total of 741 G. atlanticus specimens, caught during scientific surveys from 1997 to 2003, were analysed. The distributional patterns were described and the reproductive status estimated. Galeus atlanticus occurred throughout the Alborán Sea, between the Strait of Gibraltar and Cape Gata, including the slope of the Island of Alborán. Its bathymetric range extended from 330 to 790 m and no size depth trends have been observed. Mature specimens, both males and females, were caught in all seasons of the year. Size at first maturity was significantly different between sexes, with estimates of 32.9 cm for males and 36.9 cm for females. The differential growth of some secondary sexual characteristics, such as clasper length in males and oviducal gland diameter in females, were compared with those of G. melastomus.

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The Aerosol Direct Radiative Experiment (ADRIEX) took place over the Adriatic and Black Seas during August and September 2004 with the aim of characterizing anthropogenic aerosol in these regions in terms of its physical and optical properties and establishing its impact on radiative balance. Eight successful flights of the UK BAE-146 Facility for Atmospheric Airborne Measurements were completed together with surface-based lidar and AERONET measurements, in conjunction with satellite overpasses. This paper outlines the motivation for the campaign, the methodology and instruments used, describes the synoptic situation and provides an overview of the key results. ADRIEX successfully measured a range of aerosol conditions across the northern Adriatic, Po Valley and Black Sea. Generally two layers of aerosol were found in the vertical: in the flights over the Black Sea and the Po Valley these showed differences in chemical and microphysical properties, whilst over the Adriatic the layers were often more similar. Nitrate aerosol was found to be important in the Po Valley region. The use of new instruments to measure the aerosol chemistry and mixing state and to use this information in determining optical properties is demonstrated. These results are described in much more detail in the subsequent papers of this special issue.

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