A discussion of atmospheric circulation during the last ice age     

R.G. Barry  J.D. Ives  J.T. Andrews 《Quaternary Research》1971

  相似文献   

A note on peak-to-mean concentration ratios     

P. J. Barry 《Boundary-Layer Meteorology》1971,2(1):122-126

The peak-to-mean concentration ratio obtained from observations near a point source of pollution is a particular example of the ratio of any short-period concentration to the long-term mean. The value of this ratio may be obtained from the probability distribution function: $$F(C) = F(0) exp [ - F(0) C/M]$$ whereF(C) is the probability or frequency that the ratio of a short-period average concentration (C) to the long-term mean (M) exceeds the valueC/M, andF(0) is a parameter dependent on the length of the short period and the position of the sampler relative to the centre-line of the plume. From (1) the peak-to-mean concentration ratio is shown to be related to the two averaging times by the expression $$P/M = 1/F(0) [lnF(0) - lnt_M /t_P ]$$ wheret _M andt _P are, respectively, the averaging times of the long-term meanM and the short-term peakP. Using recently published experimental data, Equation (1) and hence also (2) are shown to be valid for averaging timest _P from 5 s to 24 h and oft _M from 6 min to 5 yr providedt _P ?t _M .  相似文献   

Partial neutrality     

W.R.P. Bourne 《Marine pollution bulletin》1980,11(11):306-307

  相似文献   

Scotland in the seventies     

W.R.P. Bourne 《Marine pollution bulletin》1980,11(2):29-31

  相似文献   

Application of matrix analysis in delineating sinkhole risk areas along highway (I-70 near Frederick,Maryland)     

Wanfang?ZhouEmail author  Barry?F.?Beck  Angela?L.?Adams 《Environmental Geology》2003,44(7):834-842

Sinkhole collapse in the area of Maryland Interstate 70 (I-70) and nearby roadways south of Frederick, Maryland, has been posing a threat to the safety of the highway operation as well as other structures. The occurrence of sinkholes is associated with intensive land development. However, the geological conditions that have been developing over the past 200 million years in the Frederick Valley control the locations of the sinkholes. Within an area of approximately 8 km², 138 sinkholes are recorded and their spatial distribution is irregular, but clustered. The clustering indicates the existence of an interaction between the sinkholes. The point pattern of sinkholes is considered to be a sample of a Gibbsian point process from which the hard-core Strauss Model is developed. The radius of influence is calculated for the recorded sinkholes which are most likely to occur within 30 m of an existing sinkhole. The stochastic analysis of the existing sinkholes is biased toward the areas with intensive land use. This bias is adjusted by considering (1) topography, (2) proximity to topographic depressions, (3) interpreted rock formation, (4) soil type, (5) geophysical anomalies, (6) proximity to geologic structures, and (7) thickness of overburden. Based on the properties of each factor, a scoring system is developed and the average relative risk score for individual 30-m segments of the study area is calculated. The areas designated by higher risk levels would have greater risk of a sinkhole collapse than the areas designated by lower risk levels. This risk assessment approach can be updated as more information becomes available.  相似文献   

Analyses of organic and inorganic contaminants in Salton Sea fish   总被引：3，自引：0，他引：3  

Riedel R  Schlenk D  Frank D  Costa-Pierce B 《Marine pollution bulletin》2002,44(5):403-411

Chemical contamination of fish from the Salton Sea, a quasi-marine lake in Southern California, could adversely impact millions of birds using the Pacific Flyway and thousands of humans using the lake for recreation. Bairdiella icistia (bairdiella), Cynoscion xanthulus (orangemouth corvina), and Oreochromis spp. (tilapia) were sampled from two river mouths and two nearshore areas of the Salton Sea. Muscle tissues were analyzed for a complete suite of 14 trace metals and 53 pesticides. Fish muscle tissues had concentrations of selenium ranging between 1.89 and 2.73 microg/g wet weight. 4,4'-DDE accounted for 94% of the total DDT metabolites. Total DDTs ranged between 17.1 and 239.0 and total PCBs between 2.5 and 18.6 ng/g wet weight. PCB congeners 132, 138, 153, 168, and 180 comprised over 50% of the total PCBs. Given the potential implementation of a commercial fishing at the Salton Sea in the future, the presence of persistent organic pollutants and selenium warrants further research into the effects of these mixtures on fish populations, and on wildlife and humans consuming fish.  相似文献   

An Anatomy of Adaptation to Climate Change and Variability   总被引：36，自引：7，他引：29  

Barry Smith  Ian Burton  Richard J.T. Klein  J. Wandel 《Climatic change》2000,45(1):223-251

Adaptation to climate variability and change is important both for impact assessment (to estimate adaptations which are likely to occur) and for policy development (to advise on or prescribe adaptations). This paper proposes an "anatomy of adaptation" to systematically specify and differentiate adaptations, based upon three questions: (i) adapt to what? (ii) who or what adapts? and (iii) how does adaptation occur? Climatic stimuli include changes in long-term mean conditions and variability about means, both current and future, and including extremes. Adaptation depends fundamentally on the characteristics of the system of interest, including its sensitivities and vulnerabilities. The nature of adaptation processes and forms can be distinguished by numerous attributes including timing, purposefulness, and effect. The paper notes the contribution of conceptual and numerical models and empirical studies to the understanding of adaptation, and outlines approaches to the normative evaluation of adaptation measures and strategies.  相似文献   

Local configuration measures for categorical spatial data: binary regular lattices     

Barry Boots 《Journal of Geographical Systems》2006,8(1):1-24

This paper examines the utility of a number of pattern measures for local exploratory analysis of binary spatial data. Based on a review of existing pattern measures in cartography, geography, image analysis, and landscape ecology, two fundamental classes of such measures, termed compositional and configurational, are identified. The paper focuses on configurational measures and it is suggested that as many as five such measures (join counts, patch numbers, patch sizes, patch proximity, and distribution of the classes relative to the focal cell of the window) are required to differentiate between all possible local categorical maps. This suggestion is explored by examining aspects of the statistical behaviour (probability distributions and correlations between extreme values of pairs of measures) of a set of 12 configurational measures. Their use is also demonstrated by means of an empirical example.  相似文献   

Multiple exposures and dynamic vulnerability: Evidence from the grape industry in the Okanagan Valley, Canada   总被引：7，自引：1，他引：7  

Suzanne Belliveau  Barry Smit  Ben Bradshaw 《Global Environmental Change》2006,16(4):364-378

This paper assesses the vulnerability of grape growers and winery operators in the Okanagan Valley, British Columbia to climate variability and change, in the context of other sources of risk. Through interviews and focus groups, producers identified the climatic and non-climatic risks relevant to them and the strategies employed to manage these risks. The results show that the presence of multiple exposures affects the way in which producers are vulnerable to climate change. Producers are vulnerable to conditions that not only affect crop yield, but also affect their ability to compete in or sell to the market. Their sensitivity to these conditions is influenced in part by institutional factors such as trade liberalization and a “markup-free delivery” policy. Producers’ ability to adapt or cope with these risks varies depending on such factors as the availability of resources and technology, and access to government programmes. Producers will likely face challenges associated with the supply of water for irrigation due to a combination of climatic changes and changing demographics in the Okanagan Valley, which in turn affect their ability to adapt to climatic conditions. Finally, adaptations made by producers can change the nature of the operation and its vulnerability, demonstrating the dynamic nature of vulnerability.  相似文献   

Parameterization of Ozone Photolysis Frequency in the Lower Troposphere Using Data from Photodiode Array Detector Spectrometers     

Evelyn Jäkel  Manfred Wendisch  Barry L. Lefer 《Journal of Atmospheric Chemistry》2006,54(1):67-87

Spectroradiometers using photodiode array detectors (PDAs) are increasingly applied for airborne and ground-based atmospheric measurements of spectral actinic flux densities due to their high time resolution (less than one second). However they have limited sensitivity of ultraviolet (UV) radiation for wavelengths less than about 305 nm. This results in uncertainties of ozone photolysis frequencies derived from spectral actinic flux density measurements using PDA spectrometers. To overcome this limitation a parameterization method is introduced which extrapolates the data towards the wavelength range of limited sensitivity of the PDA spectrometers (less than about 305 nm). The parameterization is based on radiative transfer simulations and is valid for measurements in the lower troposphere. The components of the suggested parameterization are the lower threshold wavelength of the PDA spectrometer, the slant ozone column (ratio of the total ozone column and the cosine of the solar zenith angle), and the ambient temperature. Tests of the parameterization with simulated actinic flux density spectra have revealed an uncertainty of the derived ozone photolysis frequency of ±5%. Field comparisons of the parameterization results with independent measurements of the ozone photolysis frequency were within ±10% for solar zenith angles less than 70^∘. Finally the parameterization was applied to airborne measurements to emphasize the advantage of high time resolution of PDA spectrometers to study ozone photolysis frequency fields in inhomogeneous cloud condtitions.  相似文献