Plume Dispersion in Low-Wind-Speed Conditions During Project Sagebrush Phase 2, with Emphasis on Concentration Variability

Eight short-range, open-terrain SF₆ tracer tests in low wind speeds were conducted during Phase 2 of Project Sagebrush using continuous releases. Four tests were made during very unstable conditions in July and August 2016, and four during very stable conditions in October 2016. All tests featured 10-min averaging and 1-Hz sampling of tracer concentrations together with an extensive suite of meteorological measurements. We find that the uncertainty in well-mixed daytime measurements of tracer concentrations, using the absolute value of the relative percentage difference in collocated duplicate samplers, approaches a downwind limit of about 7–8%. Concentration variability in collocated sampling, due to stochastic factors and independent of measurement uncertainty, increases the total observational uncertainty closer to the source from about 20% (daytime) to 40% (very stable conditions). Longer averaging periods moderately reduce the concentration variability. The data indicate that the large increase in concentration variability is linked with the suppression of turbulent mixing, small eddy length scales, and meandering in very stable conditions. These results should be considered when comparing observations with model predictions in evaluations.     

A Regional Measure of Neighborhood Multiple Environmental Deprivation: Relationships with Health and Health Inequalities

The health impacts of simultaneous exposure to multiple adverse environmental factors are of concern in the United Kingdom. UK-wide indicators exist, but context-specific finer resolution measures are lacking. An environmental deprivation index was developed for 398 neighborhoods (average population = 760) in a Scottish council area, including measures of air pollution, noise pollution, traffic environment, undesirable land uses, and crime. Adverse environmental conditions were related to ill health in the region and implicated in wider socioeconomic health inequalities. The results suggest an independent role for environmental deprivation in explaining poor health and health inequalities.     

A 30 million year cycle in Arctic volcanism?

Arctic perimeters volcanism has pulsed to a maximum approximately every 30 million years. This periodicity is similar to that observed on a global scale.     

Norway

This section of a two-part report is introduced by Drs Ehler and Basta of NOAA. It deals with operational discharges of oil from marine transportation sources and was compiled by Virgil F. Keith, Robert A. Mondor and Nannette J. Goldberg, of Engineering Computer Optecnomics, Inc., Annapolis, MD 21401, and Charles N. Ehler, Daniel J. Basta and Thomas F. LaPointe of the Ocean Assessments Division, Office of Oceanography and Marine Services, National Ocean Service, National Oceanic and Atmospheric Administration, Rockville, MD 20852. Charles Ehler is the Acting Chief of the division; Daniel Basta is the Acting Chief of its Strategic Assessment Branch. The second part of the report on predicting surface transport of pollutants in the Gulf will form next month's Viewpoint.     

Book reviews

WETLANDS: a threatened landscape (Institute of British Geographers Special Publication Series No.25) edited by M. Williams. 17 × 24 cm, x + 419 pp. Blackwell, Oxford 1993 (first published 1990) (ISBN 0 631 19199 2) $65.00 (soft).

GUIDE TO MAPS IN SOUTH AUSTRALIAN PARLIAMENTARY PAPERS 1852–1971 (Historical Geography Monograph No.7) edited by J. McQuilton. 21 × 29 cm, 178 pp. Australian Reference Publications, Melbourne 1994 (ISBN 0 9587876 4 6).

THE EMERGENCE OF BIOREGIONALISM IN THE MURRAY‐DARLING BASIN by J.M. Powell. 21 × 30 cm, 105 pp. Murray‐Darling Basin Commission, Canberra 1993. (ISBN 1 875209 212) $20.00 (soft).