No abstract

The winter-time arctic atmospheric boundary layer was investigated with micrometeorological and SF6 tracer measurements collected in Prudhoe Bay, Alaska. The flat, snow-covered tundra surface at this site generates a very small (0.03 cm) surface roughness. The relatively warm maritime air mass originating over the nearby, partially frozen Beaufort Sea is cooled at the tundra surface resulting in strong (4 to 30 °C · (100 m)-1) temperature inversions with light winds and a persistent weak (1 to 2 °C · (100 m)-1) surface inversion with wind speeds up to 17 m s-1. The absence of any diurnal atmospheric stability pattern during the study was due to the very limited solar insolation. Vertical profiles were measured with a multi-level mast from 1 to 17 m and with a Doppler acoustic sounder from 60 to 450 m. With high wind speeds, stable layers below 17 m and above 300 m were typically separated by a layer of neutral stability. Turbulence statistics and spectra calculated at a height of 33 m are similar to measurements reported for non-arctic, open terrain sites and indicate that the production of turbulence is primarily due to wind shear. The distribution of wind direction recorded at 1 Hz was frequently non-Gaussian for 1-hr periods but was always Gaussian for 5-min periods. We also observed non-Gaussian hourly averaged crosswind concentration profiles and assume that they can be modeled by calculating sequential short-term concentrations, using the 5-min standard deviation of horizontal wind direction fluctuations (Σθ) to estimate a horizontal dispersion coefficient (Σy), and constructing hourly concentrations by averaging the short-term results. Non-Gaussian hourly crosswind distributions are not unique to the arctic and can be observed at most field sites. A weak correlation between horizontal (Σv) and vertical (Σw) turbulence observed for both 1-hr and 5-min periods indicates that a single stability classification method is not sufficient to determine both vertical and horizontal dispersion at this site. An estimate of the vertical dispersion coefficient, Σz, could be based on ΣΦ or a stability classification parameter which includes vertical thermal and wind shear effects (e.g., Monin-Obukhov length, L). © 1989 Kluwer Academic Publishers.

Richard Lerner's new book, Final Solutions: Biology, Prejudice, and Genocide, is a powerful and troubling treatise. It weaves together several topical strands into a direct, clear, and compelling argument. The chief strength of the book lies in its focus on a single aspect of Nazi ideology (biological determinism), the role played in the maintenance of that ideology by medical and biological scientists, and Lerner's warnings about those he views as the contemporary successors of these scientists. Unlike Lerner's other contributions to the scholarly literature, this book is less a psychological treatise than it is a polemical history of some behavioral sciences in the twentieth century, Lerner's argument is provocative, clearly reasoned, and demands consideration by social scientists, humanists, and those who would avoid both the repetition of the past and our ignorance of its costs and lessons.