Remote sensing in the coastal and marine environment. Proceedings of the US North Atlantic Regional Workshop

Presentations were grouped in the following categories: (1) a technical orientation of Earth resources remote sensing including data sources and processing; (2) a review of the present status of remote sensing technology applicable to the coastal and marine environment; (3) a description of data and information needs of selected coastal and marine activities; and (4) an outline of plans for marine monitoring systems for the east coast and a concept for an east coast remote sensing facility. Also discussed were user needs and remote sensing potentials in the areas of coastal processes and management, commercial and recreational fisheries, and marine physical processes

Remote Sensing, A Tool for Managing the Marine Environment: Eight Case Studies

Case studies suggest the variety of ways in which remote sensing can be useful in studying the coastal and marine environment. It is hoped that the diversity of applications described, of data sources and platforms used (satellite/aircraft), as well as the high- quality photographs that resulted, may identify potential applications. -from STAR, 21(1), 198

A Test of the Parsons–Veronis Hypothesis on the Separation of the Gulf Stream

The Parsons–Veronis model, based on a two-layer wind-driven ocean, predicts the latitude at which the western boundary current separates from the western boundary. It has been tested on the Gulf Stream using both satellite and in situ observations. The hypothesis attributes the difference in the thermocline depth from the eastern to the western side of the ocean and the corresponding northward geostrophic transport (with closed northern end) to the southward Ekman transport integrated across the basin. Twelve years (1977–88) of satellite sea surface temperature data and wind data [from the Fleet Numerical Oceanography Center (FNOC) wind database] have been used for this study. The satellite-derived Gulf Stream northern edges were used to determine the latitudes of separation (i.e., crossing the 2000-m isobath into deep water). Parsons\u27 model is sensitive to two “free” parameters, namely, the reduced gravity and the thermocline depth on the eastern side of the basin. Based on available CTD data and previous current meter studies, these free parameters are selected to establish a representative two-layer model for the midlatitude North Atlantic. When the Ekman drift is integrated over several years, the predicted separation latitude variability agrees with observations with unit slope within 95% confidence limits. The relevant time scale of integration is on the order of 3 years, somewhat less than the estimated time for long baroclinic planetary waves to cross the Atlantic. For this limited dataset, little improvement in the prediction is found for a larger number of years of averaging. More detailed and long-term investigation of this hypothesis should be made in future in context of other western boundary currents

Serving GODAE Data and Products to the Ocean Community

The Global Ocean Data Assimilation Experiment (GODAE [http:// www.godae.org]) has spanned a decade of rapid technological development. The ever-increasing volume and diversity of oceanographic data produced by in situ instruments, remote-sensing platforms, and computer simulations have driven the development of a number of innovative technologies that are essential for connecting scientists with the data that they need. This paper gives an overview of the technologies that have been developed and applied in the course of GODAE, which now provide users of oceanographic data with the capability to discover, evaluate, visualize, download, and analyze data from all over the world. The key to this capability is the ability to reduce the inherent complexity of oceanographic data by providing a consistent, harmonized view of the various data products. The challenges of data serving have been addressed over the last 10 years through the cooperative skills and energies of many individuals

Chlorophyll enchancement and mixing associated with meanders of the shelf break front in the Mid-Atlantic Bight

Meanders of the shelf break front in the Mid-Atlantic Bight (MAB) during April and May of 1997 were associated with chlorophyll enhancement along a hydrographic and a topographic feature. The hydrographic feature was the surface outcrop of the front, which ranged from ~10 to >100 km seaward of the shelf break owing to the meanders. The topographic feature was the shelf break (100-m isobath). Chlorophyll enhancement was observed by a satellite instrument, the ocean color and temperature sensor, and by a fluorometer in situ. It developed in near-surface waters typically nutrient depleted during late spring, thus local nutrient enrichment of near-surface waters was probable. Observations of sufficient resolution to define processes were available only for the region of shelf break chlorophyll enhancement. Along two meander troughs( shoreward extremities near the shelf break), we observed shoaling of cold shelf water. Shelf water shoaled >20 m along frontal-isopycnals, and phytoplankton absorption maxima coincided directly with the shoaled water. Thus local nutrient enrichment by along-isopycnal upwelling was the supported mechanism of chlorophyll enhancement at the shelf break. The basis for along-isopycnal upwelling was seaward flow of shelf water forced by meander circulation near the shelf break. Strong cross-isobath flow and mixing developed as these meanders propagated along the shelf break front of the MAB at a relatively constant rate of ~9 km day¯¹

Satellite measurements of sea surface cooling during hurricane Gloria

Hurricanes and other strong storms can cause important decreases in sea surface temperature by means of vertical mixing within the upper ocean, and by air–sea heat exchange. Here we use satellite-derived infrared images of the western North Atlantic to study sea surface cooling caused by hurricane Gloria (1985). Significant regional variations in sea surface cooling are well correlated with hydrographic conditions. The greatest cooling (up to 5°C) occurred in slope waters north of the Gulf Stream where the seasonal thermocline is shallowest and most compressed; moderate cooling (up to 3 °C) occurred in the open Sargasso Sea where the thermocline is deeper and more diffused; little or no cooling occurred in shallow coastal waters (bottom depth less than 20 m) which were isothermal before the passage of hurricane Gloria. There is a pronounced right-side asymmetry of sea surface cooling with stronger (by a factor of 4) and more extensive (by a factor of 3) cooling found on the right side of the hurricane track. These qualitative results are consistent with the notion that vertical mixing within the upper ocean is the dominant sea surface cooling mechanism of hurricanes

Design, Realization, and Characterization of Advanced Adhesives for Joining Ultra-Stable C/C Based Components

The aim of this work is to develop high-performance adhesives to join carbon fiber reinforced composites (C/C) for use in aerospace applications; in order to guarantee sound mechanical strength, a low coefficient of thermal expansion, and ease of application on large components. Several different adhesive formulations, based on phenolic or cyanate-ester resins (charged with the maximum experimentally feasible amount of carbon-based fillers), are developed and tested. The measurements of the lap shear strength at room temperature of the C/C joined by means of one phenolic and one cyanate ester-based resin demonstrates that these formulations are the most suitable for the given application. A complete characterization, by means of viscosimetry, dilatometry, and thermal gravimetric analysis, coupled with gas analysis by means of mass spectroscopy, confirms that the phenolic-based formulation is the most promising joining material. A nano-indenter is used to obtain its Young modulus and hardness, both inside the joint and as a bulk cured adhesive