Storm catastrophes in the United States

A unique historical data set describing the 142 storms each producing losses in excess of $100 million in the United States during the 1950–89 period were analyzed to describe their temporal characteristics. The storms caused $66.2 billion in losses (in 1991 values), 76% of the nation's insured storm losses in this period. These extreme storm catastrophes (SCs) were most prevalent in the south, southeast, northeast, and central U.S., with few in and west of the Rocky Mountains. Storm incidences were high in the 1950s, low in the 1960s-early 1970s, and increased in the 1980s. Losses due to SCs peaked in the 1950s, again in the late 1960s, with a lesser peak after 1985. The areal extent of storm losses peaked after 1975 and was least in the 1960s. The temporal variations of the three storm measures (incidence, losses, and extent) did not agree except when they all peaked in the 1950s. Regionally-derived time distributions of SCs showed a marked north-south differences in the United States with a U-shaped 40-year distribution in the northern half of the nation, and a relatively flat trend until a peak in the 1980s in the southern regions. The temporal distributions of hurricane-caused catastrophes differed regionally with occurrences in the prime areas, the southern, southeastern, and northeastern U.S., each quite different. Temporal distributions of thunderstorm and winter storm catastrophes were regionally more uniform.     

Evidence for the trapped liquid shift effect in the Mount Ayliff Intrusion,South Africa

Postcumulus trapped liquid shift in layered complexes produces cumulate minerals with more fractionated compositions than the original primary phases. This effect is shown by olivine compositions from the base of the Mount Ayliff Intrusion, where varying proportions of olivine to interstitial liquid produce a suite of rocks which define a tight linear trend on a binary whole-rock plot of MgO versus FeO. Extrapolation of this trend constrains the composition of the primary cumulus olivine to the range Fo_84–86, whereas olivine actually present have compositions Fo_77–83. The magnitude of the discrepancy between the theoretical and observed olivine compositions correlates directly with the weight fraction of interstitial liquid. These observations are quantitatively predicted by the trapped liquid shift model. They also argue against significant migration of residual liquid. Trapped liquid shift is documented over a vertical interval of 60 m. It occurred in rocks lying only 1 m above the basal contact of the intrusion and hence must be a comparatively rapid process.     

Estimates of total radiation and albedo in Sub-Arctic Canada

Summary Maps have recently been prepared of the physiography and plant cover of Labrador-Ungava, in the Canadian Sub-Arctic. These enable detailed studies of representative localities to be extended over wider areas. Methods of estimating the average total insolation from sun and sky received at the surface are discussed, together with aerial measurements of albedo and thus a method of calculating the insolation absorbed by the surface is demonstrated. The limitations of the technique are stressed.

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Zusammenfassung Es wurden Karten der Physiographie und Pflanzenbedeckung von Labrador-Ungava im sub-arktischen Klimagebiet Kanadas bearbeitet; an Hand dieser Karten kann von einzelnen, repräsentativen Orten auf die Verhältnisse in größeren Gebieten geschlossen werden. Die Methoden zur Abschätzung der Globalstrahlung an der Erdoberfläche werden diskutiert. Zusammen mit Messungen der Albedo vom Flugzeug aus ergibt sich eine Möglichkeit, die vom Erdboden absorbierte Strahlungsenergie zu berechnen. Die Grenzen der Leistungsfähigkeit dieser Methode werden betont.

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Résumé On a dressé des cartes de la physiographie et de la couverture végétale du Labrador-Ungava soumis au climat subarctique du Canada. Elles permettent d'étendre les conclusions relatives à certains lieux représentatifs à de plus grands territoires. Discussion des méthodes d'estimation du rayonnement global à la surface du sol. En tentant compte de mesures de l'albédo faites depuis l'avion, on peut calculer l'énergie de rayonnement absorbée par le sol. Les limites d'application de la méthode sont discutées.

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The research described in this paper was sponsored jointly by the Carnegie Arctic Programme of McGill University and the Defence Research Board of Canada.     

The petrology of the Las Canadas volcanoes,Tenerife, Canary islands

Tenerife is the largest of the seven Tertiary to Recent volcanic islands that make up the Canary Archipelago. The island is composed of volcanics belonging to the basanitetrachyte-phonolite assemblage that characterises many Atlantic islands. The most voluminous development of intermediate and salic volcanics has been in the centre of the island where the Las Canadas volcanoes arose upon a basement shield composed mainly of basanite and ankaramite flows, tuffs and agglomerates. The initial post-shield activity built the Vilaflor volcanic complex (Lower and Upper Canadas Series) that originally covered much of the underlying shield volcanics. A vast collapse of the complex, probably during post-Pleistocene times, in the centre of the island has left a large semi-circular wall, and provides an excellent vertical section through the complex. Quaternary volcanism within the collapsed area has built the twin, central-type volcanoes, Viejo and Teide, both of which have attendant satellite vents. That part of the Vilaflor Complex exposed in Las Canadas, together with the Viejo and Teide volcanoes, comprise the Las Canadas volcanoes.Four distinct rock types can be recognised in these volcanoes, basanite, trachybasanite, plagioclase phonolite, and phonolite. Each rock type can be recognised chemically and mineralogically, but there is essentially a gradational series from basanite to phonolite that includes both aphyric and glomerophyric rocks. The volcanics are strongly undersaturated and sodic, and some of the phonolites are mildly peralkaline. Variations in degree of undersaturation, and trace element abundances indicate a number of cycles of activity which would be consistent with the known field relations.Forsteritic olivine occurs in the basanites and trachybasanites but is not a stable phase in the more salic volcanics. Clinopyroxene is ubiquitous, varying in composition from titanaugite in the basanites to slightly sodic augite in the phonolites. Strongly sodic pyroxene is restricted to the groundmass of the microcrystalline phonolites along with aenigmatite and a kataphoritic amphibole. Plagioclase is found only in the groundmass of the basanites, but andesine and potash-oligoclase are common phenocryst minerals in the trachybasanites and plagioclase phonolites respectively, whereas the characteristic feldspar of the phonolites is anorthoclase.The relatively smooth curves of major and trace element variation, the presence of accumulative volcanics at all stages of differentiation, zoning of the mineral phases, and the clustering of the phonolites around the low temperature trough in Petrogeny's Residua System, all indicate that the descent from basanite to phonolite has resulted from fractional crystallisation of a basanite parent magma. The trend of pyroxene crystallisation, and the fairly constant FeO/Fe₂O₃ ratio during fractionation indicate crystallisation under low PO₂ conditions.     

Numerical simulation of the plasma double layer

A one-dimensional particle-in-cell computer simulation is used to model the formation of an electrostatic double layer. The conditions for the onset of the layer formation are explored and a relation between the length of the layer and the electrostatic potential difference across is found.     

Infrared and Raman spectroscopy studies of the α–β phase transition in cristobalite

Infrared and Raman spectra of cristobalite are presented as a function of temperature through the phase transition. The modes are assigned and the assignments compared to those of earlier workers. The compatibility of modes at the G-point of the a-phase with the X and G-points of the ß-phase is given. In the transition region of ca. 500–550 K, smooth changes in intensity, frequency and linewidths are seen in many modes, indicative of coexistence of a- and ß-forms.     

Chemical Mechanism Development: Laboratory Studies and Model Applications

Within the German Tropospheric Research Programme (TFS) numerous kinetic and mechanistic studies on the tropospheric reaction/degradation of the following reactants were carried out: oxygenated VOC, aromatic VOC, biogenic VOC, short-lived intermediates, such as alkoxy and alkylperoxy radicals.At the conception of the projects these selected groups were classes of VOC or intermediates for which the atmospheric oxidation mechanisms were either poorly characterised or totally unknown. The motivation for these studies was the attainment of significant improvements in our understanding of the atmospheric chemical oxidation processes of these compounds, particularly with respect to their involvement in photooxidant formation in the troposphere. In the present paper the types of experimental investigations performed and the results obtained within the various projects are briefly summarised. The major achievements are highlighted and discussed in terms of their contribution to improving our understanding of the chemical processes controlling photosmog formation in the troposphere.     

Long-term changes in the type,but not amount,of ingested plastic particles in short-tailed shearwaters in the southeastern Bering Sea

We report the current (1997-1999, 2001) incidence and amount of ingested plastic in short-tailed shearwaters (Puffinus tenuirostris) in the southeastern Bering Sea and compare our results with plastic reported in shearwaters during 1970-1978. We also examine correlations between plastic loads and shearwater body mass. We found that 84% (N = 330) of shearwaters sampled in 1997-1999 and 2001 contained plastic. The incidence and amount of ingested plastic have not significantly changed since the 1970s. In contrast, the predominant type of plastic has changed over time, from industrial plastic to user plastic. S,asonal patterns in the incidence and amount of ingested plastic also changed from peak levels during early and late summer in the 1970s to mid summer in the late 1990s and 2001. We suggest that the availability of neuston plastic to seabirds in the Bering Sea has undergone a shift in composition since the 1970s. Shearwater body mass appears little if at all impaired by plastic, at least at present levels of consumption.     

Application of the luciferase cell culture bioassay for the detection of refined petroleum products

A luciferase cell culture-based bioassay, developed to detect 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-like activity of halo-genated and polycyclic aromatic hydrocarbons, was optimized to detect refined petroleum products and to determine their relative inducing potency. Quality control standards from 32 refined products (gasolines and diesels, jet fuels, lubricating oils, fuel oils and weathered products) and three commercial products were evaluated. Induction equivalents (I-EQs) were determined by direct comparison of the EC50 and EC20 values (based on the median and 20% TCDD maximal response, respectively) from dose-response curves for each product to those obtained with TCDD. Most petroleum products were active in the luciferase bioassay, with those products composed of fractions produced later in the distillation process (i.e. fuel oils) inducing higher levels. Additionally, weathering of products reduced their induction potency. Based on the high I-EQ estimates of many products, biological effects associated with exposure may have been previously underestimated using other diagnostic methods.     

Wide-Field Camera for Gravitational Microlensing Survey: MOA-cam2

We have constructed a large, mosaic CCD camera called MOA-cam2 which has 4096 × 6144-pixelsto search for gravitational microlensing events. MOA-cam2 has three4096 × 2048-pixel SITe CCD chips, which have a very high quantum efficiency (nearly 80% in the wave region 500 to 800 nm),and three buttable sides. We have placed the threechips side by side with 100 m dead space. MOA-cam2 has been installed on the 61 cm Boller and Chivens telescope of the MOA collaboration at the Mt. John University Observatory (MJUO) in NewZealand since July 1998. The field coverage is 0.92° × 1.38° per exposure. The technical details of MOA-cam2 and the first images obtained with the Boller and Chivens telescope are presented. MOA-cam2 introduces a second phase of research on gravitational microlensing by the MOA collaboration.