Vertical distribution of dissolved organic carbon (DOC) in the Western Mediterranean Sea in relation to the hydrological characteristics

Vertical profiles of dissolved organic carbon (DOC) from eight hydrological stations in the Tyrrhenian Sea, Sardinia Channel and Algerian Sea, are reported. DOC exhibits concentrations ranging from 58 to 88 μM in surface water, 43–57 μM in the intermediate layer and 49–63 μM in deep waters. The assessment of the hydrological characteristics allows different water masses in the study area to be identified; moreover, different hydrological processes are observed in the Tyrrhenian and Algerian basins. DOC exhibits different values in the different water masses. The lowest DOC concentrations (43–46 μM) were found in the Tyrrhenian Levantine Intermediate Water (LIW). Correlations between DOC and apparent oxygen utilization (AOU), investigated within each water mass, exhibit different behaviors in the intermediate and deep waters, suggesting the occurrence of different processes of oxygen consumption in the different water masses.     

Automatic Profiling System for Underice Measurements

The article is devoted to the development of an autonomous profiling system for measuring the aquatic environment under ice. The system moves up and down in the water column along a cable with a load at the lower end, which is lowered into a lane in the ice. The system carrier is designed for transporting an acoustic Doppler current profiler and a salinity, temperature, and pressure probe. The system will be useful for long-term measurements of vertical profiles of the current speed and marine environment parameters, as well as ice draft. The article describes in detail the structure and operation of the system. The hydraulic scheme of the carrier buoyancy system is presented.

     

The Equatorial Atlantic Mid-Ocean Channel: An Ultra High-Resolution Image of Its Burial History Based on TOPAS Profiles

Multibeam bathymetric and ultra high-resolution seismic data reveal that the distal course of the Equatorial Atlantic Mid-Ocean Channel (EAMOC) extends further east and south than was previously known, and is controlled by the presence of morphologic highs related to the Fernando de Noronha Fracture Zone. Distal course of the EAMOC is buried by sediments, and does not have bathymetric expression on the seafloor. The channel fill consists of three seismic sequences, suggesting that the recent geological evolution of the channel is composed of successive phases of decreasing sedimentary activity that finally resulted in its complete burial. Tectonic and volcanic activity related to the Fernando de Noronha Fracture Zone and Ridge, together with the effect of strong pulses of the Antarctic bottom water current during the upper Pliocene are suggested to have contributed to the progressive burial and the final abandonment of the EAMOC.     

THE CORRELATION BETWEEN SUNSPOT AND CORONAL HOLE CYCLES AND A FORECAST OF THE MAXIMUM OF SUNSPOT CYCLE 23

We have shown in previous papers that a close relationship exists between the evolution of polar coronal hole area, estimated from K-coronameter observations, and the Wolf sunspot number, with a time lag of about half a solar cycle. In this paper we study the same relationship, but with the total coronal hole area at the base of the corona as obtained from a potential field model of the coronal magnetic field, which provides a more complete series of about three solar cycles. We confirm the relationship for the two last cycles and find that the forward time shift in the coronal hole area for the best correlation with sunspot number is almost the same for cycles 21 and 22, and this shift is also the time between peaks in both series. We use this result to make an early prediction of the time and size of the sunspot maximum for solar cycle 23, and find that this should occur early in 2001 and have a magnitude of about 190, similar to that of the two previous sunspot cycles.     

Statistical analysis for the hydrogeological evaluation of the fracture networks in hard rocks

The hydrogeological effectiveness of fracture sets is determined and evaluated by the fuzzy c-mean and hierarchical clustering. These cluster analyses combine the geological spatial attributes and the hydraulic relevant attributes of fractures. Based on the results of the clustering the fracture set volumes are estimated.     

Jason-1: Assessment of the System Performances

On 7 December 2001, Jason-1 was successfully launched by a Boeing Delta II rocket from the Vandenberg Air Force Base, California. The Jason-1 satellite will maintain the high accuracy altimeter service provided since 1992 by TOPEX/Poseidon (T/P), ensuring the continuity in observing and monitoring the Ocean Dynamics (intraseasonal to interannual changes, mean sea level, tides, etc.). Despite one-fourth the mass and power, the Jason-1 system has been designed to have basically the same performance as T/P, measuring sea surface topography at a centimetric level. This new CNES/NASA mission also provides near real-time data for sea state and ocean forecast. The first two months of the Jason-1 mission have been dedicated to the assessment of the overall system. The goals of this assessment phase were:

1. To assess the behavior of the spacecraft at the platform and payload levels (Jason-1 being the first program to call on the PROTEUS versatile multimission platform for Low and Medium Earth Orbit Missions developed in partnership between Alcatel Space and CNES);

2. To verify that platform performance requirements are met with respect to Jason-1 requirements;

3. To verify that payload instruments performance requirements evaluated at instrument level are met;

4. To assess the performance of the Jason-1 Ground System.

This article will display the main outputs of the assessment of the system. It will demonstrate that all the elements of the onboard and ground systems are within the specifications. Provision of data to the Jason-1 Science Working Team started at the end of March 2002. This is the goal of a six-month phase after closure of the initial assessment phase to derive the error budget of the system in terms of altimetry user products.     

Recruitment patterns of Serpula vermicularis L. (Polychaeta, Serpulidae) in Loch Creran, Scotland

This study aimed to contribute to conservation management of reefs of Serpula vermicularis by increasing understanding of the factors influencing larval settlement. The study was carried out in Loch Creran, which supports the most extensive known development of S. vermicularis reefs in the world. Settlement plates were deployed to examine the influence of season, depth, reef density, substrate type and orientation. Monthly deployment of plates revealed settlement of S. vermicularis to occur predominantly from mid-June to mid-October, peaking in late August to early September. Settlement of Pomatoceros spp. peaked much earlier, in late May to early June. Deployment of plates at different depths revealed a marked reduction in S. vermicularis settlement intensity between 6 and 12 m. As this corresponds with the deeper limit of the peripheral fringe of serpulid reefs in the loch, it is suggested that this limit is imposed by a depth-correlated settlement response, rather than reduction in available substrata. Comparisons of various substrata showed a preference by S. vermicularis larvae for a slate over a scallop substrate and no evidence of enhanced recruitment to occupied or unoccupied tubes of S. vermicularis, suggesting that gregarious attraction is unlikely to be a factor causing reef formation. Settlement onto the upper side of a horizontal scallop substrate was found to be insignificant in comparison with the underside or a vertically orientated scallop. Evidence for the role of light in controlling the depth and substrate-orientation preferences of S. vermicularis larvae is discussed. Based on the results of this study, recommendations are made regarding remediation of areas suffering reef damage.     

Relaxation Time and Conductivity at a Rural Station: Raichur

An examination of decay and growth rates of electric field near the ground during total solar eclipse of 16 February 1980 was made to study the electrical relaxation time and conductivity at Raichur. The values obtained i. e., 1320 seconds and 67.1163× 10-16 mhos m-1 of the two parameters were in fair agreement with the reported ones at the rural locations.     

用机载多普勒雷达资料进行三维风场解析反演 II. 多重解析多普勒方法应用于在CaPE现场实验中获取的机载雷达实测资料

模拟结果证明，在机载雷达的技术参数下，多重解析多普勒（MANDOP）方法能够提供误差可以接受的三维风场反演。 1991年夏在美国的佛罗里达州举行的CaPE现场实验中首次应用了机载双束多普勒雷达，并获取了珍贵的雷达实测资料。用MANDOP方法分析1991年8月9日观测到的一个飑线，取得类似于以往用地基雷达资料得到飑线内部大气环流结构。另外，机载雷达资料与 地基雷达资料联合反演的结果与纯粹用机载雷达资料反演的结果之间很好的相关性证明了机载雷达资料的可靠性。