Book reviews

Behavioural biology of killer whales. Editors: C. Kirkevold and J. S. Lockard. Zoo Biology Monographs, Volume 1. Alan Liss Inc., New York, 1986. 457 p. ISBN 0–8451–3100–1. Price: US$79.50.

Aquaculture of Cyprinids. Editors: R. Billard and J. Marcel. Institut National de la Recherche Agronomique, 1986. 504 p. Price FF150.00. Available from INRA Publications, Route de St Cyr, 78000 Versailles, France.

The Peruvian anchoveta and its upwelling ecosystem: three decades of change. Editors: D. Pauly and I. Tsukayama. Institute) del Mar del Peru (IMARPE); Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ); International Center for Living Aquatic Resources Management (ICLARM) 1987.351 p. ISBN 971–1022–34–6, ISSN 0115–4389. Price US$17.50 surface; US$36 airmail. Available from ICLARM, MCP.O. 1501, Makati, Metro Manilla, Philippines.

The freshwater planktonic blue‐greens (Cyanophyta/Cyanobacteria) of New Zealand: a taxonomic guide. By M. K. Etheredge and R. D. Pridmore. Published for the National Water and Soil Conservation Authority, 1987. 122 p, including 93 figures. ISSN0110–4705. Price $38.50. Available from DSIR Publishing, P.O. Box 9741, Wellington, New Zealand.     

An integrative geological and geophysical approach to characterize a superficial deltaic aquifer in the Camargue plain,France

Deltaic aquifers are complex due to the important heterogeneity of their structure and their hydrogeological functioning. Auger drilling provides localized, but very robust geological and hydrogeological information, while geophysical surveys can provide integrated subsurface information. An effective, easy-to-use and low-cost methodology combining geological/hydrogeological information from Auger drillings and the results from three geophysical techniques (Electromagnetic mapping, Electrical Sounding and Electrical Resistivity Tomography) is being developed to characterize the structure of a typical Mediterranean deltaic aquifer. A first hypothesis about hydrodynamic properties of the aquifer is also obtained. The study area is located in the Rhone delta (Middle Camargue/southern France). Integration of geophysical and geological techniques allowed identifying the presence and lateral extension of the Saint-Ferréol paleochannel, the vertical contact between lagoonal–fluvial deposits and the marine clayed silt that separate the superficial aquifer from the deeper aquifer. Likewise, high north–south heterogeneity and east–west homogeneity were highlighted in the study area. Presence of clay in sandy deposits in the low areas implies changes in lateral hydraulic permeability. This fact, jointed to the low hydraulic gradient, suggests a slow groundwater flow in the local system. The Rhone delta presents a typical configuration of a Mediterranean deltaic aquifer, thus this methodological approach can be used for similar deltaic Mediterranean systems.     

The Third GABLS Intercomparison Case for Evaluation Studies of Boundary-Layer Models. Part B: Results and Process Understanding

We describe and analyze the results of the third global energy and water cycle experiment atmospheric boundary layer Study intercomparison and evaluation study for single-column models. Each of the nineteen participating models was operated with its own physics package, including land-surface, radiation and turbulent mixing schemes, for a full diurnal cycle selected from the Cabauw observatory archive. By carefully prescribing the temporal evolution of the forcings on the vertical column, the models could be evaluated against observations. We focus on the gross features of the stable boundary layer (SBL), such as the onset of evening momentum decoupling, the 2-m minimum temperature, the evolution of the inertial oscillation and the morning transition. New process diagrams are introduced to interpret the variety of model results and the relative importance of processes in the SBL; the diagrams include the results of a number of sensitivity runs performed with one of the models. The models are characterized in terms of thermal coupling to the soil, longwave radiation and turbulent mixing. It is shown that differences in longwave radiation schemes among the models have only a small effect on the simulations; however, there are significant variations in downward radiation due to different boundary-layer profiles of temperature and humidity. The differences in modelled thermal coupling to the land surface are large and explain most of the variations in 2-m air temperature and longwave incoming radiation among models. Models with strong turbulent mixing overestimate the boundary-layer height, underestimate the wind speed at 200 m, and give a relatively large downward sensible heat flux. The result is that 2-m air temperature is relatively insensitive to turbulent mixing intensity. Evening transition times spread 1.5 h around the observed time of transition, with later transitions for models with coarse resolution. Time of onset in the morning transition spreads 2 h around the observed transition time. With this case, the morning transition appeared to be difficult to study, no relation could be found between the studied processes, and the variation in the time of the morning transition among the models.     

Observed Changes in One-in-20 Year Extremes of Canadian Surface Air Temperatures

Weather and climate extremes are often associated with substantial adverse impacts on society and the environment. Assessment of changes in extremes is of great and broad interest. This study first homogenizes daily minimum and maximum surface air temperatures recorded at 146 stations in Canada. In order to assess changes in one-in-20 year extremes (i.e., extremes with a 20-year return period) in temperature, annual maxima and minima of both daily minimum temperatures and daily maximum temperatures are derived from the homogenized daily temperature series and analyzed with a recently developed extreme value analysis approach based on a tree of generalized extreme value distributions (including stationary and non-stationary cases). The procedure is applied to estimate the changes over the period 1911 to 2010 at 115 stations, located mainly in southern Canada, and over the period 1961 to 2010 at 146 stations across Canada (including 37 stations in the North). The results show that warming is strongest for extreme low temperature and weakest for extreme high temperature and is much stronger in the Canadian Arctic than in southern Canada. Warming is stronger in winter than in summer and stronger during nighttime than daytime of the same season.     

The development of an interactive multi-scale GIS

Abstract

This paper presents the development of the first geographical information system (GIS) that may be used to manipulate a single dataset at a very large range of scales (different detail levels). The design of this multi-scale GIS is fully integrated in the open DBMS Postgres and the open GIS GEO + + . Besides the system design, this paper will also give details of the implementation in the Postgres DBMS environment of three generalization tools: 1. the BLG-tree for line and area simplification, 2. the Reactive-tree for selection based on importance and location, and 3. the GAP-tree for solving problems when using the other two structures for an area partitioning. Together with the geographical frontend, the DBMS forms the flexible basis for the realization of powerful GIS applications. The implementation has been successfully benchmarked with two large datasets: World Databank II and DLMS DFAD. The response times improve by one to two orders of magnitude.     

Choosing methods for estimating dissolved and particulate riverine fluxes from monthly sampling

Abstract

In discrete water quality surveys, riverine fluxes are associated with unknown uncertainties (biases and imprecisions). Annual flux errors have been determined from the generation of discrete surveys by Monte Carlo sorting for monthly sampling, from 10 years of daily records (120 records). Eight calculation methods were tested for suspended particulate matter, dissolved solids and dissolved and total nutrients in medium to large basins (10³ to 10⁶ km²) covering a wide range of hydrological conditions and riverine biogeochemistry. The performance of each method was analysed first by type of riverine material, which appeared to be much less pertinent than the flux variability matrix. The latter combines the river flow duration in two percent of time (W_2%) and the truncated exponent (b_50sup) defining the relationship of concentration vs discharge (C–Q) at higher flows (C = aQ^b50sup). As flux variability increases (high W_2% and/or high b_50sup), averaging and rating curve methods become less efficient compared to hydrograph separation methods. Flux biases and imprecisions were plotted in the [W_2%, b_50sup] matrix for discrete monthly surveys.

Editor Z. W. Kundzewicz

Citation Raymond, S., Moatar, F., Meybeck, M., and Bustillo, V., 2013. Choosing methods for estimating dissolved and particulate riverine fluxes from monthly sampling. Hydrological Sciences Journal, 58 (6), 1326–1339.     

Metal‐saturated sulfide assemblages in NWA 2737: Evidence for impact‐related sulfur devolatilization in Martian meteorites

NWA 2737, a Martian meteorite from the Chassignite subclass, contains minute amounts (0.010 ± 0.005 vol%) of metal‐saturated Fe‐Ni sulfides. These latter bear evidence of the strong shock effects documented by abundant Fe nanoparticles and planar defects in Northwest Africa (NWA) 2737 olivine. A Ni‐poor troilite (Fe/S = 1.0 ± 0.01), sometimes Cr‐bearing (up to 1 wt%), coexists with micrometer‐sized taenite/tetrataenite‐type native Ni‐Fe alloys (Ni/Fe = 1) and Fe‐Os‐Ir‐(Ru) alloys a few hundreds of nanometers across. The troilite has exsolved flame‐like pentlandite (Fe/Fe + Ni = 0.5–0.6). Chalcopyrite is almost lacking, and no pyrite has been found. As a hot desert find, NWA 2737 shows astonishingly fresh sulfides. The composition of troilite coexisting with Ni‐Fe alloys is completely at odds with Chassigny and Nahkla sulfides (pyrite + metal‐deficient monoclinic‐type pyrrhotite). It indicates strongly reducing crystallization conditions (close to IW), several log units below the fO₂ conditions inferred from chromites compositions and accepted for Chassignites (FMQ‐1 log unit). It is proposed that reduction in sulfides into base and precious metal alloys is operated via sulfur degassing, which is supported by the highly resorbed and denticulated shape of sulfide blebs and their spongy textures. Shock‐related S degassing may be responsible for considerable damages in magmatic sulfide structures and sulfide assemblages, with concomitant loss of magnetic properties as documented in some other Martian meteorites.     

Soil erosion risk assessment of the Keiskamma catchment,South Africa using GIS and remote sensing

This paper examines the soil loss spatial patterns in the Keiskamma catchment using the GIS-based Sediment Assessment Tool for Effective Erosion Control (SATEEC) to assess the soil erosion risk of the catchment. SATEEC estimates soil loss and sediment yield within river catchments using the Revised Universal Soil Loss Equation (RUSLE) and a spatially distributed sediment delivery ratio. Vegetation cover in protected areas has a significant effect in curtailing soil loss. The effect of rainfall was noted as two pronged, higher rainfall amounts received in the escarpment promote vegetation growth and vigour in the Amatole mountain range which in turn positively provides a protective cover to shield the soil from soil loss. The negative aspect of high rainfall is that it increases the rainfall erosivity. The Keiskamma catchment is predisposed to excessive rates of soil loss due to high soil erodibility, steep slopes, poor conservation practices and low vegetation cover. This soil erosion risk assessment shows that 35% of the catchment is prone to high to extremely high soil losses higher than 25 ton ha⁻¹ year⁻¹ whilst 65% still experience very low to moderate levels of soil loss of less than 25 ton ha⁻¹ year⁻¹. Object based classification highlighted the occurrence of enriched valley infill which flourishes in sediment laden ephemeral stream channels. This occurrence increases gully erosion due to overgrazing within ephemeral stream channels. Measures to curb further degradation in the catchment should thrive to strengthen the role of local institutions in controlling conservation practice.     

Interactions of diffuse and focused allogenic recharge in an eogenetic karst aquifer (Florida, USA)

The karstic upper Floridan aquifer in north-central Florida (USA) is recharged by both diffuse and allogenic recharge. To understand how recharged water moves within the aquifer, water levels and specific conductivities were monitored and slug tests were conducted in wells installed in the aquifer surrounding the Santa Fe River Sink and Rise. Results indicate that diffuse recharge does not mix rapidly within the aquifer but instead flows horizontally. Stratification may be aided by the high matrix porosity of the eogenetic karst aquifer. Purging wells for sample collection perturbed conductivity for several days, reflecting mixing of the stratified water and rendering collection of representative samples difficult. Interpretive numerical simulations suggest that diffuse recharge impacts the intrusion of allogenic water from the conduit by increasing hydraulic head in the surrounding aquifer and thereby reducing influx to the aquifer from the conduit. In turn, the increase of head within the conduits affects flow paths of diffuse recharge by moving newly recharged water vertically as the water table rises and falls. This movement may result in a broad vertical zone of dissolution at the water table above the conduit system, with thinner and more focused water-table dissolution at greater distance from the conduit.