KEYWORDS: Data modeling, Coastal modeling, Atmospheric modeling, Satellites, 3D modeling, Microwave radiation, Radiometry, Climatology, Data processing, Global Positioning System
Satellite altimetry has proved successful as a global tool for monitoring sea surface height, significant wave height and
wind speed. Nevertheless, a global archive of 17 years of raw data from a series of missions is presently unexploited
around the world coastline. This huge amount of unused data can be re-analyzed, improved and more intelligently
exploited, possibly promoting coastal altimetry to the rank of operational service. Operational users interested in
monitoring sea level change and wave conditions in the coastal zone (e.g. for coastal erosion, sediment/pollutant
transport applications) still rely on sparse (and expensive) in situ monitoring stations or poor models. In this work we
present a new approach in the exploitation of altimeter data in the coastal zone (currently impeded by unsuitable
waveform retracking scheme and coarse along-track spatial sampling in the coastal zone, among others). The objective
of this paper is to show how a new, robust, retracking algorithm is able to retrieve with high accuracy physical ocean
parameters from altimeter waveforms in the coastal zone. The main focus lies on retrieving sea surface height in the
coastal zone with the same precision as is achieved in the open ocean. In addition, the retrieval of more accurate
altimeter-derived wave products in the coastal zone is also important as waves are more directly relevant to many
operational applications in the coastal zone.
Fifteen years of global altimetry data over the coastal ocean lie, largely unexploited, in the data archives, simply because
intrinsic difficulties in the corrections and issues of land contamination in the footprint. These data would be invaluable
for studies of coastal circulation, sea level change and impact on the coastline. Amongst some initiatives, we describe
here the COASTALT Project, funded by ESA. The main objective of the COASTALT Project is to contribute towards
making the status of pulse-limited coastal altimetry operational. In this paper we will first illustrate the first project
phase, based on the assessment of user requirements, and summarize those requirements. Then we will describe the
COASTALT methodology and objectives. Finally, we will illustrate and discuss the various options for coastal
waveform retracking, and present a plan for the validation of the retracked data. The first results in the radar altimeter
waveform analysis show the complexity of the coastal signals due to land contamination and calm/rough waters.
Nanolithography based on atomic force microscopy is a widely used techniques for the prototyping of nanostructures. This technique has attracted great attention due to its simplicity, versatility and precise control. Oxidation is performed at normal atmosphere where the meniscus connecting tip and surface plays a key role. The present study describes the electrical conductivity of this nanometer-size meniscus. By acquiring force vs distance curves, we determine the relationship between the tip-surface separation and electrical current. It is observed an increase of the electrical current at small finite separations (< 2 nm) due to a change in water meniscus properties, and a decrease of electrical current when the meniscus is elongated.
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