Applications of remote sensing to estuarine management

Projects for sewage outfall siting for pollution control in the lower Chesapeake Bay wetlands are reported. A dye-buoy/photogrammetry and remote sensing technique was employed to gather circulation data used in outfall siting. This technique is greatly favored over alternate methods because it is inexpensive, produces results quickly, and reveals Lagrangian current paths which are preferred in making siting decisions. Wetlands data were obtained by interpretation of color and color infrared photographic imagery from several altitudes. Historical sequences of photographs are shown that were used to document wetlands changes. Sequential infrared photography of inlet basins was employed to determine tidal prisms, which were input to mathematical models to be used by state agencies in pollution control. A direct and crucial link between remote sensing and management decisions was demonstrated in the various projects

Precision measurement of the Casimir-Lifshitz force in a fluid

The Casimir force, which results from the confinement of the quantum mechanical zero-point fluctuations of the electromagnetic fields, has received significant attention in recent years for its effect on micro- and nano-scale mechanical systems. With few exceptions, experimental observations have been limited to conductive bodies interacting separated by vacuum or air. However, interesting phenomena including repulsive forces are expected to exist in certain circumstances between metals and dielectrics when the intervening medium is not vacuum. In order to better understand the effect of the Casimir force in such situations and to test the robustness of the generalized Casimir-Lifshitz theory, we have performed the first precision measurements of the Casimir force between two metals immersed in a fluid. For this situation, the measured force is attractive and is approximately 80% smaller than the force predicted by Casimir for ideal metals in vacuum. We present experimental results and find them to be consistent with Lifshitz's theory.Comment: 6 pages, 3 figures. (version before final publication

Chapter 12: Vulnerability of fishes of the Great Barrier Reef to climate change

Climate change has already caused significant impacts to Earth’s ecosystems. Shifts in plant and animal biogeographic ranges, changes to population abundance, adjustments in the timing of seasonal activities and the establishment of invasive species have all been attributed to climate change. Most examples of biological impacts from climate change involve terrestrial species, however, similar effects have been observed in marine species, especially from temperate regions. The impact of climate change on coral reefs has also been widely considered, mostly with regard to coral bleaching and the degradation of coral communities. Much less attention has been given to the impact that climate change will have on other organisms that are associated with coral reefs. Fish are one of the most conspicuous and diverse components of tropical marine ecosystems, yet how they will be affected by climate change has not been comprehensively assessed.This is Chapter 12 of Climate change and the Great Barrier Reef: a vulnerability assessment. The entire book can be found at http://hdl.handle.net/11017/13

How responsible is a region for its carbon emissions? An integrated input-output and CGE analysis

Targets for CO2 reduction tend to be set in terms of the amount of pollution generated within the borders of a given region or nation. That is, under a "production accounting principle". However, in recent years there has been increased public and policy interest in the notion of a carbon footprint, or the amount of pollution generated globally to serve final consumption demand within a region or nation. That is, switching focus to a "consumption accounting principle". However, this paper argues that a potential issue arising from the increasing focus on consumption-based "carbon footprint" type measures is that while regional CO2 generation embodied in export production is attributed outside of the region (i.e. to the carbon footprints of other regions/nations), regional consumers are likely to benefit from such production. Moreover, where there is a geographical and supply chain gap between producers and final consumers, it may be difficult to identify precisely "whose" carbon footprint emissions should be allocated to. We demonstrate our argument by using a regional computable general equilibrium (CGE) model of the Welsh economy to simulate the impacts of an increase in export demand for the output of an industry (metal manufacturing) that is both carbon and export intensive and generally produces to meet intermediate rather than final demands. In doing so, we demonstrate how the CGE model results may be used to create „post-shock‟ input-output accounts to examine changes in the structure of economic activity and the resulting impact on CO2 generation under both production and consumption accounting measures. In this respect, to our knowledge, the current paper makes a novel contribution in using CGE techniques to model "carbon footprint" impacts of a change in economic activity

Stable suspension and dispersion-induced transitions from repulsive Casimir forces between fluid-separated eccentric cylinders

Using an exact numerical method for finite nonplanar objects, we demonstrate a stable mechanical suspension of a silica cylinder within a metallic cylinder separated by ethanol, via a repulsive Casimir force between the silica and the metal. We investigate cylinders with both circular and square cross sections, and show that the latter exhibit a stable orientation as well as a stable position, via a method to compute Casimir torques for finite objects. Furthermore, the stable orientation of the square cylinder is shown to undergo an unusual 45 degrees transition as a function of the separation lengthscale, which is explained as a consequence of material dispersion.Comment: Published in Physical Review Letters. Vol. 101, page, 190404 (2008

Incorporating jurisdiction issues into an analysis of carbon attributable to Welsh final consumption under different economic conditions: an integrated IO and CGE analysis

This paper considers the combined use of regional input-output (IO) and computable general equilibrium (CGE) methods to examine regional pollution problems from different consumption and production orientated perspectives. The first stage of the analysis involves using a regional input-output framework and data derived on direct CO2 (as carbon) generation by industry (and in household final consumption) to examine regional accountability for CO2 generation. In doing we consider an accounting method that permits greater accountability of regional private and public (household and government) final consumption as the main driver of regional carbon generation, while retaining focus on the local production, technology and consumption decisions that fall under the jurisdiction of regional policymakers. However, we go on to argue that a potential issue arising from the increasing focus on consumption-based „carbon footprint‟ type measures is that regional CO2 generation embodied in export production is attributed outside of the region, while regional consumers are likely to benefit from such production. We demonstrate our argument by using a regional CGE model to simulate the impacts of an increase in export demand for regional production on key macroeconomic variables, including GDP, employment and household consumption, as well as on different measures of CO2 attributable to regional consumption. In terms of the latter, we demonstrate how CGE model results may be used to create „post-shock‟ IO accounts to permit the calculation of CO2 generation under the various production and consumption accounting principles considered in the first part of the paper. Our empirical analyses focus on the case example of the Welsh regional economy and an anticipated increase in export demand for the output of one of the biggest polluting sectors, Iron and Steel production

The retroflection of part of the East Greenland Current at Cape Farewell

The East Greenland Current (EGC) and the smaller East Greenland Coastal Current (EGCC) provide the major conduit for cold fresh polar water to enter the lower latitudes of the North Atlantic. They flow equatorward through the western Irminger Basin and around Cape Farewell into the Labrador Sea. The surface circulation and transport of the Cape Farewell boundary current region in summer 2005 is described. The EGCC merges with Arctic waters of the EGC to the south of Cape Farewell, forming the West Greenland Current. The EGC transport decreases from 15.5 Sv south of Cape Farewell to 11.7 Sv in the eastern Labrador Sea (where the water becomes known as Irminger Sea Water). The decrease in EGC transport is balanced by the retroflection of a substantial proportion of the boundary current (5.1 Sv) into the central Irminger Basin; a new pathway for fresh water into the interior of the subpolar gyre

Turbulent drag on a low-frequency vibrating grid in superfluid He-4 at very low temperatures

We present measurements of the dissipative turbulent drag on a vibrating grid in superfluid He-4 over a wide range of (low) frequencies. At high velocities, the dissipative drag is independent of frequency and is approximately the same as that measured in normal liquid He-4. We present measurements on a similar grid in superfluid He-3-B at low temperatures which shows an almost identical turbulent drag coefficient at low frequencies. However, the turbulent drag in He-3-B is substantially higher at higher frequencies. We also present measurements of the inertial drag coefficient for grid turbulence in He-4. The inertial drag coefficient is significantly reduced by turbulence in both superfluid and normal liquid He-4

Towards improved socio-economic assessments of ocean acidification’s impacts

Ocean acidification is increasingly recognized as a component of global change that could have a wide range of impacts on marine organisms, the ecosystems they live in, and the goods and services they provide humankind. Assessment of these potential socio-economic impacts requires integrated efforts between biologists, chemists, oceanographers, economists and social scientists. But because ocean acidification is a new research area, significant knowledge gaps are preventing economists from estimating its welfare impacts. For instance, economic data on the impact of ocean acidification on significant markets such as fisheries, aquaculture and tourism are very limited (if not non-existent), and non-market valuation studies on this topic are not yet available. Our paper summarizes the current understanding of future OA impacts and sets out what further information is required for economists to assess socio-economic impacts of ocean acidification. Our aim is to provide clear directions for multidisciplinary collaborative research

Measurements of the Casimir-Lifshitz force in fluids: the effect of electrostatic forces and Debye screening

In this work, we present detailed measurements of the Casimir-Lifshitz force between two gold surfaces (a sphere and a plate) immersed in ethanol and study the effect of residual electrostatic forces, which are dominated by static fields within the apparatus and can be reduced with proper shielding. Electrostatic forces are further reduced by Debye screening through the addition of salt ions to the liquid. Additionally, the salt leads to a reduction of the Casimir-Lifshitz force by screening the zero-frequency contribution to the force; however, the effect is small between gold surfaces at the measured separations and within experimental error. An improved calibration procedure is described and compared to previous methods. Finally, the experimental results are compared to Lifshitz's theory and found to be consistent for the materials used in the experiment.Comment: 11 figures. PRA in pres