Doppler profiles of the 5577 Å airglow

We discuss the altitude and intensity of the nocturnal green line emission resulting from O₂⁺ recombination. The Doppler profile of this emission is markedly non-thermal, the width being characteristic of the energy at which the O(¹S) atoms are produced. A simple theory is formulated which predicts the profile of this line. Experimental evidence on airglow line profiles is reviewed and it is found that the effect predicted here has not yet been observed. However a deliberate search for this effect should yield immediate results.     

A strategy for monitoring of contaminant distributions resulting from proposed sewage sludge disposal at the 106-mile ocean disposal site

It has been proposed that future ocean disposal of sewage sludge from the US east coast be done at a site beyond the edge of the continental shelf. In anticipation of that, a monitoring strategy has been developed to determine the average spatial distribution of contamination. The strategy is an iterative series of measurements developed from models of sludge dispersion and settling which are based on characteristics of the disposal site and sewage sludge. Once disposal is initiated at the site, the strategy requires sampling the upper mixed layer at 36 stations, mostly within 100 km of the site, and deployment of near-bottom sediment traps along a line extending 300 km away from the site. Based on initial results, subsequent sampling locations will be selected to refine estimates of the detectable extent of sludge-derived contamination. The sludge constituents which can be used to detect sludge in water at a dilution of 10⁶ and sludge in sediment traps when diluted by 100 with natural material include zinc, PCBs, coprostanol and spores of the bacterium Clostridium perfringens. Other synthetic organic compounds, besides PCB, may prove to be useful tracers.     

Something is wrong with climate theory

We frequently forget that there is more to science than the making of a more precise measurement or a more elaborate calculation. It is even more than applying to new problems the methods that worked on old problems. These activities, which keep most of us busy most of the time, are important, but the new and unexpected discoveries are more important. And many radically new discoveries arise from scientific puzzles, the "anomalies." We believe that studies of past climates have exposed an anomaly that deserves attention and that may result in a fundamentally new understanding of the climate system. The poles have been much warmer throughout much of Earth's history than they are now. Ice-age episodes with durations of millions of years have been separated by periods of hundreds of millions of years that have left little or no evidence of polar ice sheets. The data are best for the most recent of these ice-free episodes so we will concentrate on the Eocene.     

Concrete: a man‐made rock?

It has been said that concrete is a ‘man‐made rock’ and although the comparison is not perfect, we support this general statement. It is broadly similar in texture to breccias or conglomerates, has a cementitious matrix, has broadly similar physical properties to some sedimentary and igneous rocks and performs somewhat similarly to masonry during its working life in a building or engineering structure. The investigation and testing of concrete have many similarities to those used for the evaluation of building stone.     

Ecological Risk Assessment for seabird interactions in Western and Central Pacific longline fisheries

The risk of seabird–fishery interactions in the Western and Central Pacific Ocean (WCPO) was examined by analysing the overlap of seabird distributions with tuna and swordfish pelagic longline fisheries managed by the Western and Central Pacific Fisheries Commission (WCPFC) and its constituent members. The study used spatially-explicit Productivity–Susceptibility Analysis (PSA). Key data inputs were species productivity, fishing effort, likelihood of capture and species density by region. The outputs tailored results to the needs of fisheries- and wildlife-managers, indicating areas of greatest risk of species interactions, species of greatest concern for population impacts, and the flags or fisheries most likely to contribute to the risk. Large albatross species were found to be most likely to suffer population effects when exposed to longline fishing activity, followed by the larger petrels from the genuses Procellaria, Macronectes and Pterodroma. A mixture of coastal states with nesting seabird populations in their Exclusive Economic Zones (New Zealand, Australia and United States of America), distant water fishing nations (Japan, Taiwan) and flags of convenience (Vanuatu) contributed 90% of the risk to seabird populations. Recommendations include enhancing the level of fisheries observer monitoring in areas indicated as high to medium risk for seabird interactions, and consideration of spatial management tools, such as more intensive or more stringent seabird bycatch mitigation requirements in high- to medium-risk areas. The methods used, and similar studies conducted in the Atlantic Ocean could lead to improved targeting of monitoring resources, and greater specificity in the needs for seabird-mitigation measures. This will assist in reducing seabird mortality in longline fishing operations and with more effective use of resources for fishery managers in both domestic fisheries and RFMOs.     

Formal definition and dating of the GSSP (Global Stratotype Section and Point) for the base of the Holocene using the Greenland NGRIP ice core,and selected auxiliary records

The Greenland ice core from NorthGRIP (NGRIP) contains a proxy climate record across the Pleistocene–Holocene boundary of unprecedented clarity and resolution. Analysis of an array of physical and chemical parameters within the ice enables the base of the Holocene, as reflected in the first signs of climatic warming at the end of the Younger Dryas/Greenland Stadial 1 cold phase, to be located with a high degree of precision. This climatic event is most clearly reflected in an abrupt shift in deuterium excess values, accompanied by more gradual changes in δ¹⁸O, dust concentration, a range of chemical species, and annual layer thickness. A timescale based on multi‐parameter annual layer counting provides an age of 11 700 calendar yr b2 k (before AD 2000) for the base of the Holocene, with a maximum counting error of 99 yr. A proposal that an archived core from this unique sequence should constitute the Global Stratotype Section and Point (GSSP) for the base of the Holocene Series/Epoch (Quaternary System/Period) has been ratified by the International Union of Geological Sciences. Five auxiliary stratotypes for the Pleistocene–Holocene boundary have also been recognised. Copyright © 2008 John Wiley & Sons, Ltd.     

Hemispheric-scale climate response to Northern Eurasia land surface characteristics and snow anomalies

This paper presents a synopsis of recently published studies by the co-authors, which show that several land surface characteristics unique to Northern Eurasia are responsible for facilitating a causal relationship between autumn snow anomalies in this region and subsequent hemispheric winter climate patterns. The large size and extratropical location of the contiguous Eurasian land mass results in broad, continental-scale interannual snow cover extent and depth variations throughout autumn and winter, and corresponding diabatic heating anomalies. These surface anomalies occur in the presence of a large region of stationary wave activity, produced in part by the orographic barriers that separate northern/central Eurasia from southern/eastern Eurasia. This co-location of snow-forced anomalies and ambient wave energy is unique to Northern Eurasia, and initiates a teleconnection pathway involving stationary wave–mean flow interaction throughout the troposphere and stratosphere, ultimately resulting in a modulation of the winter Arctic Oscillation (AO). Complementary new results are also presented which show that partial snow cover extent or snow depth only anomalies in Northern Eurasia are insufficient to initiate the teleconnection pathway and produce a winter AO signal. This synopsis provides a useful interpretation of the earlier studies in the specific context of Northern Eurasia regional climate and environmental change.     

Exchange rates,soybean supply response,and deforestation in South America

The advancement of South America's agro-pastoral frontier has been widely linked to losses in biodiversity and tropical forests, with particular impacts on the Brazilian cerrado, the Atlantic Forest, and the Amazon. Here we consider an important, yet largely overlooked, driver of South America's soybean expansion, namely the devaluation of local currencies against the US dollar in the late 1990s and early 2000s. Much interest has emerged in recent years over the environmental implications of soybean production in Brazil, with evidence of both direct incursions into moist tropical forest by soybean producers and of potential indirect effects, via the displacement of existing ranching operations. In this research we utilize historical trends in soybean prices, exchange rates, and cropland dedicated to soybean production in Bolivia, Paraguay, and Brazil to estimate the impact of currency devaluations on area of production. The results suggest that approximately 80,000 km², or 31% of the current extent of soybean production in these countries, emerged as a supply area response to the devaluation of local currencies in the late 1990s. The results also indicate that the more recent depreciation of the dollar and appreciation of the Brazilian real have counteracted a recent rise in global soybean prices, in the process sparing an estimated nearly 90,000 km² from new cropland, 40,000 km² of this in the Amazon alone. Amidst an increasingly neoliberal economic environment, where barriers to trade are jettisoned in favor of the free flow of commodities, relative currency values will occupy an important role in the future sourcing of both agricultural expansion and environmental degradation.     

Historical Gorda Ridge t-phase swarms: relationships to ridge structure and the tectonic and volcanic state of the ridge during 1964–1966

The U.S. Navy’s Sound Surveillance System (SOSUS) hydrophone arrays are extemely efficient receptors of a high-frequency earthquake energy phase known as the t(ertiary)-wave, or t-phase (Fox et al., 1994). After a nearly 30-year hiatus in such studies, SOSUS arrays are again being utilized to detect t-phases and to locate seismic and volcanic events occurring along the Gorda seafloor spreading center (Fox et al., 1995; Fox and Dziak, 1998). Earlier, Northrop et al. (1968) also used other military arrays to infer tectonic structure along the Gorda Ridge. From October 1964 through December 1966, over 600 low-magnitude earthquakes occurred along the Gorda Ridge. Nearly all of these events had magnitudes below the detection thresholds of land-based seismic networks. Northrop et al. (1968) interpreted the geographic distribution of these events as evidence for a nascent fracture zone near the midpoint of the ridge. In the present study, the spatial distributions of these older data and, for the first time, their temporal distributions as well, were examined with respect to detailed bathymetry of the ridge that was acquired in the early 1980s. This analysis, of 570 on-axis and 74 off-axis events, led to the following observations: (1) nearly all of the Gorda Ridge t-phase events occurred in discreet swarms centered about the ridge axis, (2) most of the events within each of 8 (of 9) observed swarms occurred mainly along single ridge segments, and, (3) reconfirming the earlier Northrop et al. (1968) conclusion, most of the events originated in the region of a major change in the strike of the ridge axis. During the 27-month interval that the ridge was observed, relatively few t-phase events took place along the northernmost segment of the Gorda Ridge where the 1996 eruption occurred. However, a unique sequence of small events which visually resemble the events associated with a Juan de Fuca Ridge eruption in 1993 (Fox et al., 1995) and a Gorda Ridge eruption in 1996 (Fox and Dziak, 1998) may have been associated with an eruption on the ridge during 1965.     

Theory-guided machine learning to predict density evolution of sand dynamically compacted under Ko condition

Acta Geotechnica - This paper introduces a theory-guided machine learning (TGML) framework, which combines a theoretical model (TM) and a machine learning (ML) algorithm to predict compaction...