Possible impacts of climate change on extreme weather events at local scale in south–central Canada

Synoptic weather typing and regression-based downscaling approaches have become popular in evaluating the impacts of climate change on a variety of environmental problems, particularly those involving extreme impacts. One of the reasons for the popularity of these approaches is their ability to categorize a complex set of meteorological variables into a coherent index, facilitating the projection of changes in frequency and intensity of future daily extreme weather events and/or their impacts. This paper illustrated the capability of the synoptic weather typing and regression methods to analyze climatic change impacts on a number of extreme weather events and environmental problems for south–central Canada, such as freezing rain, heavy rainfall, high-/low-streamflow events, air pollution, and human health. These statistical approaches are helpful in analyzing extreme events and projecting their impacts into the future through three major steps or analysis procedures: (1) historical simulation modeling to identify extreme weather events or their impacts, (2) statistical downscaling to provide station-scale future hourly/daily climate data, and (3) projecting changes in the frequency and intensity of future extreme weather events and their impacts under a changing climate. To realize these steps, it is first necessary to conceptualize the modeling of the meteorology, hydrology and impacts model variables of significance and to apply a number of linear/nonlinear regression techniques. Because the climate/weather validation process is critical, a formal model result verification process has been built into each of these three steps. With carefully chosen physically consistent and relevant variables, the results of the verification, based on historical observations of the outcome variables simulated by the models, show a very good agreement in all applications and extremes tested to date. Overall, the modeled results from climate change studies indicate that the frequency and intensity of future extreme weather events and their impacts are generally projected to significantly increase late this century over south–central Canada under a changing climate. The implications of these increases need be taken into consideration and integrated into policies and planning for adaptation strategies, including measures to incorporate climate change into engineering infrastructure design standards and disaster risk reduction measures. This paper briefly summarized these climate change research projects, focusing on the modeling methodologies and results, and attempted to use plain language to make the results more accessible and interesting to the broader informed audience. These research projects have been used to support decision-makers in south–central Canada when dealing with future extreme weather events under climate change.     

Temporal and spatial variability of SSTs in the tropical Atlantic and Indian Oceans

Summary The objective of this study is to describe spatial and temporal patterns of sea-surface temperature (SST) variability in the Atlantic and Indian Oceans. The analysis domain extends from 40°S to 25°N and 50°W to 80°E, hence the tropical and most of the South Atlantic and central and western Indian Oceans. The investigation, covering the years 1948 to 1979, utilizes the COADS marine data set. Empirical orthogonal functions and spectral analysis are used to analyze SST fields.A major finding of this investigation is that SSTs vary coherently throughout most of the analysis domain. The greatest coherence is evident from 10°N to 30°S in the Atlantic and from 20°N to 35°S in the western Indian Ocean. Spectral analysis of regional time series shows that throughout this region the time scale of 5–6 years is the dominant one in the fluctuations; this is also the case for the Southern Oscillation and for equatorial rainfall. SST variations are roughly in-phase within each ocean and the two oceans are roughly in-phase with each other, i.e., the lags which exist are much smaller than the dominant time scale of the fluctuations. The SST anomalies appear to propagate eastward from NE Brazil; the eastern Atlantic lags the western by two to six months and the Indian Ocean lags the western Atlantic by four to eight months.With 15 Figures     

Rainfall Conditions in Equatorial East Africa during the Nineteenth Century as Inferred from the Record of Lake Victoria

The East African lakes have exhibited dramaticfluctuations on both historical and paleo-climatictime scales. Levels of these lakes, and otherhistorical indicators in Africa, suggested thatenvironmental conditions in the nineteenth centurywere much more extreme than anything evident in themodern record. In this study, a water balance modelis used to estimate the rainfall associated with theseconditions, based on the Lake Victoria record. Theresults suggest that the conditions were not unlikeanomalous periods found during the twentieth century,but they may have persisted for somewhat longerperiods of time. The paper also demonstrates ageneric tool that can be applied to interpretinghistorical and paleo-lake levels in quantitative termsof rainfall.     

The problem of origin,deformation and recrystallization of calcite-quartz bodies

The calcite-quartz bodies which occur in the Upper Wenlock slaty succession of Llangollen have a distinctive fabric of platy calcite crystals and coarse, sometimes euhedral, quartz. The calcite internal deformation lamellae and folds and boudins formed in the bodies during the production of the folds and cleavage of the country rock are described together with the recrystallization fabrics of some of the calcite. Note is made of similar rocks from Ribblesdale and Coniston and their origin discussed.     

Development of slaty cleavage in a mudstone unit from the Cantabrian Mountains, northern Spain

A 200 m thick mudstone unit in the Carboniferous of the Cantabrian Mountains, northern Spain, exhibits an increase in intensity of the slaty cleavage from top to bottom which appears to be correlated with a decrease in the mean grain size, average bed thickness and quartz: mica ratio. Anastomosing cleavage domains, formed by pressure solution and by kinking and rotation of the detrital micas, become closer spaced, wider and more continuous towards the finer-grained base of the unit. Growth of strongly oriented new micas within the cleavage domains also appears to be correlated with the intensity of the domain development and hence with the initial lithology. Clay minerals have been completely replaced throughout the mudstone by muscovite, paragonite and pyrophyllite during low-grade metamorphism. The growth of an oriented mica fabric, however, is restricted to samples with well-developed cleavage domains.     

Cardiac and Lysosomal Responses to Periodic Copper in the Mussel Perna viridis (Bivalvia: Mytilidae)

Biological monitoring of metals in marine waters often employs tissue residue analyses from bivalves. Chemical residues in tissues do not elucidate biological injury, however, whereas biomarkers, do afford sensitive stress indices. Physiological and cytological responses were evaluated in laboratory experiments from the mussel Perna viridis in order to assess the species’ suitability for pollution monitoring in the tropics. Periodic copper exposure increased tissue residues but failed to perturb cardiac activity. Copper destabilized haemocyte lysosomal membranes in a exposure-dependent relationship showing a sensitive, rapid, indication of stress. Cytological biomarkers from P. viridis have potential as indices of pollutant exposure and could facilitate effective biomonitoring of water quality throughout South-east Asia.     

Characterization of dissolved organic matter fluorescence in the South Atlantic Bight with use of PARAFAC model: Interannual variability

Systematic water sampling for characterization of chromophoric dissolved organic matter (CDOM) in the coastal South Atlantic Bight, was conducted as part of the long term Coastal Ocean Research and Monitoring Program (CORMP). Water samples were collected during a 3.5 year period, from October 2001 until March 2005, in the vicinity of the Cape Fear River (CFR) outlet and in adjacent Onslow Bay (OB). During this study there were two divergent hydrological and meteorological conditions in the CFR drainage area: a severe drought in 2002, followed by the very wet year of 2003. CDOM was characterized optically by the absorption coefficient at 350 nm, the spectral slope coefficient (S), and by Excitation Emission Matrix (EEM) fluorescence. Parallel Factor Analysis (PARAFAC) was used to assess CDOM composition from EEM spectra and six components were identified: three terrestrial humic-like components, one marine humic-like component and two protein-like components. Terrestrial humic-like components contributed most to dissolved organic matter (DOM) fluorescence in the low salinity plume of the CFR. The contribution of terrestrial humic-like components to DOM fluorescence in OB was much smaller than in the CFR plume area. Protein-like components contributed significantly to DOM fluorescence in the coastal ocean of OB and they dominated DOM fluorescence in the Gulf Stream waters. Hydrological conditions during the observation period significantly impacted both concentration and composition of CDOM found in the estuary and coastal ocean. In the CFR plume, there was an order of magnitude difference in CDOM absorption and fluorescence intensity between samples collected during the drought compared to the wet period. During the drought, CDOM in the CFR plume was composed of equal proportions of terrestrial humic-like components (ca. 60% of the total fluorescence intensity) with a significant contribution of proteinaceous substances (ca. 20% of the total fluorescence). During high river flow, CDOM was composed mostly of humic substances (nearly 75% of total fluorescence) with minor contributions by proteinaceous substances. The impact of changes in fresh water discharge patterns on CDOM concentration and composition was also observed in OB, though to a lesser degree.     

Soil redistribution and pedologic transformations in coastal plain croplands

In agricultural basins of the southeastern coastal plain there are typically large disparities between upland soil erosion and sediment delivered to streams. This suggests that colluvial storage and redistribution of eroded soil within croplands is occurring, and/or that processes other than fluvial erosion are at work. This study used soil morphology and stratigraphy as an indicator of erosion and deposition processes in a watershed at Littlefield, North Carolina. Soil stratigraphy and morphology reflect the ways in which mass fluxes associated with cultivation transform the local soils. Fluvial, aeolian and tillage processes were all found to be active in the redistribution of soil. The soil transformations are of five general types. First, erosion and compaction in the cultivated area as a whole result in the thinning of Arenic and Grossarenic Paleudults and Paleaquults to form Arenic, Typic and Aquic Paleudults and Paleaquults. Second, redistribution of surficial material within the fields results in transitions between Arenic and Typic or Aquic subgroups as loamy sand A and E horizons are truncated or accreted. Third, aeolian deposition at forested field boundaries leads to the formation of compound soils with podzolized features. Fourth, sandy rill fan deposits at slope bases create cumulic soils distinct from the loamy sands of the source area or the darker, finer terrace soils buried by the fan deposits. Finally, tillage and fluvial deposition in upland depressions results in the gradual burial of Rains (poorly drained Typic Paleaquults) soils. Results confirm the importance of upland sediment storage and redistribution, and the role of tillage and aeolian processes as well as fluvial processes in the region. Copyright © 1999 John Wiley & Sons, Ltd.     

Developing underutilized fisheries: Oregon's developmental fisheries program

Oregon's Developmental Fisheries Program is designed to encourage the commercial exploration and development of State managed underutilized fishery resources. A key program strategy is allocating relatively secure harvest rights to pioneering entrepreneurs when a fishery successfully transitions from “developing” to “developed” status. Since the program's inception in 1993, two fisheries, sardine and bay clam, have moved from undeveloped to developed status. Case studies of these fisheries show that many challenges impact the success of the Developmental Fisheries Program including difficulties in designing and allocating asset rights, establishing operational program guidelines, selecting measurable targets that meet legislative standards for a developed fishery, and financing developmental fisheries management practices. Developmental fisheries strategies used in other regions and countries are summarized. Recommendations are made for improving Oregon's Developmental Fishery Program including establishing clear objectives and timelines for the Program and identifying appropriate renewal requirements for permits and other developmental incentives on a fishery-by-fishery basis.