Chloride in precipitation and streamwater for the upland catchment of river severn,mid-wales; some consequences for hydrochemical models

Variations in the concentration of Cl in rainfall and stream runoff are presented for two catchments in the Hafren forest of mid-Wales, Great Britain. Despite the large fluctuations in rainfall concentrations, Cl in the streamwater remains relatively constant. Using the two-reservoir Birkenes model, an attempt was made to simulate observed Cl in streamwater. The original model was unable to reproduce the observations and several modifications are suggested to provide better simulations. The resulting model is not the only one capable of reproducing the observations; other hydrochemical models will most probably also achieve this although emphasis will in each case be placed on different aspects. In this paper, it is suggested that the stochastic properties of water movement and chemical processes can account for the streamwater chemistry responses observed. On the catchment scale these processes will lead to an apparently deterministic behaviour that may well be described by simple relationships.     

Equilibrium models of differentially-rotating polytropic cylinders

The equilibrium structure of differentially rotating polytropic cylinders is determined numerically. We setn=3 and use a quadratic function for the law of differential rotation. We construct different models by varying the angular velocity at the axis and the ratio of the angular velocity at the surface to the angular velocity at the axis. By taking a decreasing function for the rotation law we are able to treat models with an angular velocity at the axis greater than the break-up velocity of uniformly rotating cylinders. We also determine whether a Richardson-like criterion for stability is violated in the models.     

The earth is our home: systemic metaphors to redefine our relationship with nature

Climate change is one of the most compelling challenges for science communication today. Societal reforms are necessary to reduce the risks posed by a changing climate, yet many people fail to recognize climate change as a serious issue. Unfortunately, the accumulation of scientific data, in itself, has failed to compel the general public on the urgent need for pro-environmental policy action. We argue that certain metaphors for the human-environment relationship can lead people to adopt a more nuanced and responsible conception of their place in the natural world. In two studies, we tested properties of multiple metaphors with the general public (study 1) and experts on climate change (study 2). The metaphor “the earth is our home” resonated with climate experts as well as diverse subpopulations of the general public, including conservatives and climate-change deniers.     

Applicability of Kinetic Models for In Situ Combustion Processes with Different Oil Types

The in situ combustion (ISC) process is of interest as an enhanced oil recovery method because it is an alternative to traditional steam-based processes for heavy oil and bitumen recovery. ISC is a technique applicable outside the window of reservoir conditions deemed appropriate for steam injection (such as deeper and thinner reservoirs). The process involves complex chemical reactions and physical recovery mechanisms, and predicting the likelihood of successful ISC in field applications remains challenging. This paper describes a numerical investigation of the capability of different ISC kinetic models to predict the combustion behaviors of different types of oils (light oil, heavy oil, and bitumen). Three kinetic models (of Coats, Crookston, and Belgrave) were selected from literature and compared using data from four published combustion-tube experiments. The comparison procedure is as follows: (1) validate the numerical modeling of each kinetic model by matching the selected experimental results or duplicating the numerical results found in published literature; (2) adjust fluid viscosities and densities to match the fluid properties of each experiment;and (3) use each validated kinetic model to predict the performance of the other experiments without further tuning the kinetic parameters. The knowledge derived from the experiments provides guidance for choosing the appropriate kinetic model when no other data are available and for the preliminary design and screening study of a potential ISC project.     

Avalanche Climatology of the Western United States,with an Emphasis on Alta,Utah*

Climate and snowpack characteristics of avalanches vary spatially across the western United States, distinguishing three regions. The coastal mountain renges have warmer, denser snow; interior (continental) ranges have colder, less-dense snow; and intermountain ranges have intermediate characteristics. Avalanche character of Alta, Utah, is related to eastern Pacific 700-mb height anomalies for December, January, and March, but not for February. Avalanche conditions around Alta do not always relate to localized pressure gradient winds for December and February.     

Small-Scale Retrospective Ground Water Monitoring Study for Simazine in Different Hydrogeological Settings

A ground water monitoring study was conducted for the triazine herbicide simazine at 11 sites in the United States. The study used carefully selected, small-scale sites (average size: about 33 acres) with documented product use and sensitive hydrogeological settings. The sites selected were Tulare County, California (two sites); Fresno County, California; Sussex County, Delaware; Hardee and Palm Beach counties, Florida; Winnebago County, Illinois; Jackson County, Indiana; Van Buren and Berrien counties, Michigan; and Jefferson County, West Virginia. These sites satisfied the following criteria: a history of simazine use, including the year prior to the start of the study; permeable soil and vadose zone; shallow depth to water; no restrictive soil layers above the water table; and gentle slopes not exceeding 2 percent. A variety of crop types, climates, and irrigation practices were included. Monitoring well clusters (shallow and deep) were installed at each site except in California and West Virginia, where only shallow wells were installed. Simazine was monitored at these sites at quarterly intervals for a two-year period during 1986–1988.
The results of the study showed that out of 153 samples analyzed, 45 samples showed simazine detections. A substantial majority of the detections (32 out of 45) occurred in Tulare, Fresno, and Jefferson counties. The detections in these areas were attributed to mechanisms other than leaching, such as drainage wells, karst areas, surface water recharge, or point source problems. An additional 11 detections in Van Buren County were apparently due to an unknown upgradient source. Only one detection (in Palm Beach County, Florida) near the screening level of 0.1 ppb was attributed to possible leaching. The results of this investigation support the hypothesis that simazine does not leach significantly under field use conditions.