Distribution of the Planktonic Shrimp Lucifer (Thompson, 1829) (Decapoda, Sergestoidea) off the Amazon

Lucifer faxoni (BORRADAILE, 1915) and L. typus (EDWARDS, 1837) are species first identified in the neritic and oceanic waters off the Amazon. Samplings were made aboard the vessel “Antares” at 22 stations in July and August, 2001 with a bongo net (500-µm mesh size). Hydrological data were taken simultaneously for comparative purposes. L. faxoni was present at thirteen of the fourteen neritic stations analysed, as well as at five of the eight oceanic stations. L. typus was present at three of the fourteen neritic stations and in one of the eight oceanic stations. The highest density of L. faxoni in the neritic province was 7,000 ind.m–3 (St. 82) and 159 ind.m–3 (St. 75) in the oceanic area. For L. typus, the highest density observed was 41 ind.m–3 (St. 64) in the neritic province. In the oceanic province, the highest single density value was recorded at station 75 (5 ind.m–3). Overall, L. faxonitypically presented the highest densities.

Communication System Improvement for Air Traffic Service to Provide a Continuous Surveillance over the Oceanic Area

Air traffic service is an extra-ventricular service which regulates and assists aircraft in real time to ensure their safe operations. The importance of the air traffic service is to prevent collision between aircraft and to expedite and maintain an orderly flow of the air traffic. The objective of this project is to assess the effectiveness of the installed system in assisting the air traffic controller in providing the air traffic service. In order to achieve this objective, the Automatic Dependent Surveillance and Controller Pilot Data Link Communication (ADS/CPDLC) system has been installed and its functionality to provide continuous surveillance and communication has been evaluated. A survey of 35 air traffic controllers had participated to assess the effectiveness of the system to the air traffic controller. The results showed that over 80% of the air traffic controllers agree that the system is able to provide a continuous surveillance and continuous communication over the oceanic area. Apart from that, 60% of the air traffic controllers agree the reduced separation minima can be applies over the oceanic area by using the application of the system. Base on this result, reduced separation minima over the oceanic area can be applied in order to expedite and maintain an orderly flow of air traffic over the oceanic area.

The tides of the northeast Atlantic Ocean

The results of a ten-year programme of measurement and analysis of the tides in the open sea west of Europe are described. Instrumental techniques were developed during the period from capacitance-plane sensors used in shelf seas to strain-gauges and quartz crystal sensors used in oceanic depths up to about 4 km. The measuring stations form two chains, one on the edge of the shelf surrounding the British Isles, and the other surrounding an oceanic area bounded by Scotland, Iceland, the Azores and South Portugal, which is subdivided by a line of stations along the 53 1/2 ° parallel from Inishbofin to the mid-Atlantic Ridge. Records from tide gauges at strategic oceanic sites were collected and analysed over long periods to provide a basis for accurate analysis of the relatively short-term pelagic pressure records. Tidal admittances to the generating potential vary smoothly over the region except for a change in the age (phase slope) of the diurnal tides towards Reykjavik. The shelf-edge chain included current meters, enabling a direct estimation of the M 2 power transmission on to the shelf, namely 60 GW between Malin Head (Eire) and Floro (Norway) and 190 GW between Valentia (Eire) and the Brittany coast near Ouessant. When combined with known power fluxes into the Irish Sea and through the Dover Strait, these give figures for tidal dissipation in the North and Scottish seas that considerably exceed direct estimates based on bottom friction, confirming similar results by Robinson (1979) for the Irish Sea. Dissipation in the English Channel and western Celtic Sea is also much greater than was assumed by Miller (1966). Further, when the eastward flux of energy out of the ocean is computed solely on the basis of the cotidal map drawn for M 2 it is found that about 360 GW is fed into the shelf region between Lisbon and Valentia Island, indicating a substantial loss along the Biscay shelf south of Ouessant. Thus, all estimates of energy loss in the region studied greatly exceed previously assumed values. Dissipation within the main oceanic area itself is, however, about as small as expected. The diurnal tides in the shelf zones are considerably unlike Kelvin-waves, having short wavelength variations and a tendency for larger amplitudes on the open shelf than at the coast. This probably results from the presence of shelf-wave modes previously identified only in the region of St Kilda. The semi-diurnal tides however have much more regular behaviour along the shelf, with a Kelvin-wave profile west of Inishbofin. The tidal constants at two representative oceanic sites are compared with estimates from recent computational models, with wide ranges from fair agreement to disagreement, showing that tidal computations for the North Atlantic are not so uncontroversial as is often supposed. Avoiding reliance on computational modelling, the authors present cotidal maps of plausible accuracy for the constituents O 1 , K 1 , M 2 , S 2 and M 3 . Currents and power fluxes calculated from the M 2 map are presented and discussed. The principal oceanic amphidromes for the diurnal and semi-diurnal tides are west of the area studied, but their positions are estimated reliably. A major semi-diurnal amphidrome east of Iceland is confirmed, but there is no evidence for a supposed amphidrome centred on the Faeroe Islands. The cotidal map for M 3 is the first ever produced for an oceanic area. It contains two amphidromes near the mid-Atlantic Ridge.