The spatial distribution of tornadoes and high wind impacts associated with inland-moving tropical cyclones in the southeastern United States

The southeastern United States is routinely hit by tropical cyclones (TC). As TC track inland and dissipate their inland impacts can be substantial. This study examined the spatial patterns of societal impacts associated with tornadoes and high winds with 31 inland-moving TC that made landfall from 1985 to 2008. Hourly weather information was collected from all available first-order weather stations affected by each storm, as well as tropical cyclone preliminary reports issued from the National Hurricane Center. Societal impacts were identified through selected newspapers across the region and the National Climatic Data Center’s Storm Data. Geographic Information System (GIS) software was employed to make geometric measurements of the distance and direction of the impacts relative to storm center. From these measurements, the spatial distribution of the societal and meteorological impacts was plotted relative to the track (e.g., left vs. right) and location (forward vs. rear sector) of the cyclone center. Various tropical cyclone attributes, including size, strength, and forward speed of movement were then related to the occurrence of different impacts and their location relative to the cyclone track. The majority of tropical cyclone tornado and high wind impacts occur in the right-forward sector of the tropical cyclone. However, many TC produce impacts that occur in other sectors far from the center of circulation. These abnormalities are associated in many cases with interactions between the tropical cyclone circulation, topography, peripheral dry air, and extratropical synoptic weather features.     

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).     

Hidden philosophies: How geographic thought has been limited by its theoretical models

Dominant theoretical models in geography have been drawn by analogy from theories in economics and biology. The philosophical assumptions which underlie this transfer are normally unexamined. The economic model itself rests on a mechanical analogy and on a philosophy of science which emphasizes empiricism, determination and reductionism. The ecological model, while realist at base, is limited by the ontological priority it grants to Nature. Though some recent approaches in Marxism echo these old antinomies, a Marxist model based on the philosophy of internal relations offers an opportunity to transcend these barriers.     

Comparison of Nutrient and Microbial Dynamics over a Seasonal Cycle in a Mid-Atlantic Coastal Lagoon Prone to <Emphasis Type="Italic">Aureococcus anophagefferens</Emphasis> (Brown Tide) Blooms

To determine the roles of dissolved organic matter in the onset, duration, and decline of blooms of the “brown tide” pelagophyte, Aureococcus anophagefferens, nutrient and microbial dynamics, heterotrophic and autotrophic carbon (C) and nitrogen (N) uptake, and peptide hydrolysis were compared in natural populations: (1) seasonally, among physically similar sites in a mid-Atlantic coastal lagoon, Chincoteague Bay, (2) at an individual site as a bloom initiated, developed, and declined, and (3) in whole versus size-fractionated water. Throughout the year, urea was the dominant form of N taken up at both bloom and nonbloom sites. C acquisition in the A. anophagefferens (1.2–5.0 μm) size fraction was dominated by bicarbonate uptake during bloom initiation but organic C compounds were taken up later during and after the bloom. Bacterial productivity was enhanced during and just after the bloom and bacterial abundance was four times higher at the bloom versus nonbloom site.     

Effect and timing of increased freshwater runoff into sheltered harbor environments around Auckland City, New Zeland

Two short cores of late Holocene, low tidal, estuarine sediment from the sheltered fringes of the Auckland's Waitemata Harbor, New Zealand, record the following changes through time since human colonization: an abrupt decline and disappearance of marine molluscs, a major decline and virtual disappearance of ostracods, an abrupt decline in calcareous foraminifera (mostlyAmmonia spp.), a rapid increase, in abundance of agglutinated foraminifera, large diatoms, and freshwater thecamoebians, and an increase in sedimentation rate, but no consistent trend in change of grain size. The up-core foraminiferal changes mimic their present day up-estuary zonation, which correlates strongly with decreasing salinity and pH. In both localities the faunal changes can be correlated with the documented local land-use history and increased freshwater runoff over time. At the head of the Waitemata Harbor, in Lucas Creek estuary, three phases of foraminiferal faunal change occurred: minor changes during initial Polynesian forest clearance (1500–1800 AD), a major change in early European times (1840–1870 AD) with clearance of most of the remaining native forest, and another small change in very, recent times (∼1990s) with urbanization in the Lucas Creek catchment. On the eastern, seaward fringes of the Waitemata Harbor, in the smaller Tamaki Estuary, no faunal changes occurred in association with complete forest clearance and establishment of pastoral farming in Polynesian and early European times (before 1950s). Major foraminiferal and other faunal changes occurred in the late European period (1960s–1970s) coincident with the onset of major urbanization spreading throughout the Tamaki catchment. Our results suggest increased freshwater runoff is the major culprit for many of the observed biotic changes in the urbanized estuaries of New Zealand.     

Blooms of Dinoflagellate Mixotrophs in a Lower Chesapeake Bay Tributary: Carbon and Nitrogen Uptake over Diurnal,Seasonal, and Interannual Timescales

A multi-year study was conducted in the eutrophic Lafayette River, a sub-tributary of the lower Chesapeake Bay during which uptake of inorganic and organic nitrogen (N) and C compounds was measured during multiple seasons and years when different dinoflagellate species were dominant. Seasonal dinoflagellate blooms included a variety of mixotrophic dinoflagellates including Heterocapsa triquetra in the late winter, Prorocentrum minimum in the spring, Akashiwo sanguinea in the early summer, and Scrippsiella trochoidea and Cochlodinium polykrikoides in late summer and fall. Results showed that no single N source fueled algal growth, rather rates of N and C uptake varied on seasonal and diurnal timescales, and within blooms as they initiated and developed. Rates of photosynthetic C uptake were low yielding low assimilation numbers during much of the study period and the ability to assimilate dissolved organic carbon augmented photosynthetic C uptake during bloom and non-bloom periods. The ability to use dissolved organic C during the day and night may allow mixotrophic bloom organisms a competitive advantage over co-occurring phytoplankton that are restricted to photoautotrophic growth, obtaining N and C during the day and in well-lit surface waters.