Land Surface Temperature Patterns in the Urban Agglomeration of Krakow (Poland) Derived from Landsat-7/ETM+ Data   总被引：1，自引：0，他引：1  

Jakub P. Walawender  Mariusz Szymanowski  Monika J. Hajto  Anita Bokwa 《Pure and Applied Geophysics》2014,171(6):913-940

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Juncture of erosion,land use/cover status and hazardous geomorphic processes in central lesser Himalaya     

Anita Pande 《Journal of the Geological Society of India》2017,89(4):444-452

The high relief energy of the central lesser Himalayan terrain of Jaigan watershed would indicate to favour the occurrence of highly active geomorphic processes. Present investigation was based on two watersheds with different juncture of erosion, viz. Ghuniyoli and Santri watershed under youthful and equilibrium state of erosion respectively. The juncture of erosion of these watersheds was assessed under the impact of altitudinal variation as well as the erosion environment of these studied watersheds was evaluated under different land use/cover status. However, the present morphodynamics of Ghuniyoli and Santri watersheds can be considered for the detailed investigation of physical factors including geological situation as well as the cultural factors. The litho-structural set-up completely altered the sequential development of landform. The landscape under the resistant strata had undergone equilibrium (early mature) juncture while vulnerable lithology determined youthful (late) juncture. This occurred due to the active tectonics of the watershed. The existence of thrust along with contact zone of two lithologies created more erosion prone conditions in resistant strata. Land use/cover status when compared with juncture of erosion for the entire watershed also followed the same juncture of erosion. Finally it was observed that the juncture of erosion was reflected in hazardous geomorphic processes too. Landform under youthful juncture caused significant hazardous geomorphic processes in comparison to landform under mature juncture.  相似文献   

Soil moisture and rainfall intensity thresholds for runoff generation in southwestern Wisconsin agricultural watersheds   总被引：1，自引：0，他引：1  

Timothy F. Radatz  Anita M. Thompson  Frederick W. Madison 《水文研究》2013,27(25):3521-3534

The goal of this study was to improve understanding of the factors that influence runoff generation during non‐frozen ground periods in small agricultural watersheds in southwestern Wisconsin where the landscapes are controlled by dolostone bedrock in order to provide agricultural producers with a manure management tool. Six small watersheds (ranging from 6 to 17 ha) within two southwestern Wisconsin farm sites (Discovery Farms Program (DFP) and Pioneer Farm (PF)) were instrumented, and surface runoff was continuously monitored from 2004 to 2007. The soils in all watersheds were formed in deep (~1 m) loessial sites. A direct‐plant management strategy and corn‐soybean crop rotation were utilized within watersheds at DFP. A conventional tillage system (chisel plow in the fall followed by soil finisher in the spring) and a corn‐oat‐alfalfa crop rotation were utilized within watersheds at PF. At PF, the amount of precipitation leaving the landscape as surface runoff (1.8%) was two times greater compared to DFP (0.9%), indicating that the direct‐plant management system was better at retaining precipitation than the chisel plow/soil finisher system. Using breakpoint regression analysis, a non‐linear response in runoff generation with antecedent soil moisture (ASM) was observed with a threshold ASM of 0.39 cm³cm^?3 (approximately 80% of total porosity) for all six watersheds. Below this threshold, runoff coefficients were near zero. Above this threshold, runoff coefficients increased with ASM. A non‐linear response in runoff generation with maximum 30 min rainfall intensity (I30) was also observed, and threshold I30 values increased as ASM decreased and as crop cover increased. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Measuring long-run economic effects of natural hazard     

Robert McComb  Young-Kyu Moh  Anita R. Schiller 《Natural Hazards》2011,58(1):559-566

This paper studies the long-run economic effects of severe weather on regional economies. A catastrophic event, such as a hurricane, will have an effect on both the directly impacted region and adjacent regions. With dramatically increasing damage from catastrophic weather events over the past few decades, comprehensive assessment of the long-run economic impact of natural disasters across the broader region becomes more important than ever for planning for post-disaster recovery. We estimate the long-run effect of Hurricane Katrina on the unemployment rate of Houston, TX by employing time-series and fixed-effect models. Using Dallas as a control, we find that Katrina is associated with a higher long-run unemployment rate in Houston than would otherwise have been expected. This implies that the hurricane-generated adverse relative effects on Houston. Our findings suggest that areas that are geographically proximate to the directly impacted region can sustain lasting negative economic consequences.  相似文献   

Professionalization of the shipping industry via postgraduate education     

Adolf K.Y. Ng  Anita C. Koo  Athanasios A. Pallis 《Ocean & Coastal Management》2011,54(5):364-373

The paper investigates the roles and nature of postgraduate education on the professionalization of the shipping industry. The recent growth of postgraduate education is marked by the massive expansion of professional programmes on disciplines which traditionally emphasized non-academic, apprentice-style learning approach, including shipping business and management. The reasons behind such growth of demands, however, have remained scarce and empirically under-researched. Understanding this deficiency, in this study, we have undertaken a questionnaire survey completed by students/graduates who are pursuing/have recently pursued masters' programmes in shipping-related business and management offered by six Asian and European universities. Specifically, we analyze student motivations, considerations, and sources of information before enrolling such programmes, the extent that the shipping industry or other forces act as driving forces towards such enrollment, as well as students' evaluation of the postgraduate programmes that they are pursing/have pursued. Integrated in these discussions are comparative analyses of the data provided by different student groups based on their professional experiences and cultural backgrounds. We believe that this study has provided the lacking empirical inputs essential for achieving the sustainable development of postgraduate education in shipping business and management.  相似文献   

Crystal reaming during the assembly, maturation, and waning of an eleven-million-year crustal magma cycle: thermobarometry of the Aucanquilcha Volcanic Cluster   总被引：1，自引：1，他引：0  

Barry A. Walker Jr.  Erik W. Klemetti  Anita L. Grunder  John H. Dilles  Frank J. Tepley  Denise Giles 《Contributions to Mineralogy and Petrology》2013,165(4):663-682

Phenocryst assemblages of lavas from the long-lived Aucanquilcha Volcanic Cluster (AVC) have been probed to assess pressure and temperature conditions of pre-eruptive arc magmas. Andesite to dacite lavas of the AVC erupted throughout an 11-million-year, arc magmatic cycle in the central Andes in northern Chile. Phases targeted for thermobarometry include amphibole, plagioclase, pyroxenes, and Fe–Ti oxides. Overall, crystallization is documented over 1–7.5 kbar (~25 km) of pressure and ~680–1,110 °C of temperature. Pressure estimates range from ~1 to 5 kbar for amphiboles and from ~3 to 7.5 kbar for pyroxenes. Pyroxene temperatures are tightly clustered from ~1,000–1,100 °C, Fe–Ti oxide temperatures range from ~750–1,000 °C, and amphibole temperatures range from ~780–1,050 °C. Although slightly higher, these temperatures correspond well with previously published zircon temperatures ranging from ~670–900 °C. Two different Fe–Ti oxide thermometers (Andersen and Lindsley 1985; Ghiorso and Evans 2008) are compared and agree well. We also compare amphibole and amphibole–plagioclase thermobarometers (Ridolfi et al. 2010; Holland and Blundy 1994; Anderson and Smith 1995), the solutions from which do not agree well. In samples where we employ multiple thermometers, pyroxene temperature estimates are always highest, zircon temperature estimates are lowest, and Fe–Ti oxide and amphibole temperature estimates fall in between. Maximum Fe–Ti oxide and zircon temperatures are observed during the middle stage of AVC activity (~5–3 Ma), a time associated with increased eruption rates. Amphibole temperatures during this time are relatively restricted (~850–1,000 °C). The crystal record presented here offers a time-transgressive view of an evolving, multi-tiered subvolcanic reservoir. Some crystals in AVC lavas are likely to be true phenocrysts, but the diversity of crystallization temperatures and pressures recorded by phases in individual AVC lavas suggests erupting magma extensively reams and accumulates crystals from disparate levels of the middle to upper crust.  相似文献   

Role of a rheophyte in bench development on a sand‐bed river in southeast Australia     

Wayne Erskine  Anita Chalmers  Annabelle Keene  Michael Cheetham  Richard Bush 《地球表面变化过程与地形》2009,34(7):941-953

Casuarina cunninghamiana Miq. is an important rheophytic tree in New South Wales, Australia because it is fast growing and can tolerate flood disturbance. Widden Brook is an active sand‐bed stream that has widened substantially since initial European settlement in the early 1800s and is characterized by high flood variability and multi‐decadal periods of alternating high and low flood frequency, called flood‐ and drought‐dominated regimes. Channel contraction by bench formation is currently occurring. Conversion of coarse‐grained point bars to benches is an important process of channel contraction. When point bars grow to a height where suspended sediment is first deposited to thicknesses of at least 50 mm by sub‐bankfull floods, rapid establishment of C. cunninghamiana occurs. As the trees grow they partially block bankside flows, thereby locally reducing flow velocity and inducing further deposition on the benches. Such synergistic relationships between bar height and inundation, fine‐grained sediment deposition, tree establishment and the development of a bankside low current velocity zone are fundamental for bench development. Size‐class frequency data demonstrate that C. cunninghamiana on the benches consists of pure even‐aged stands with most trees clustering near the average diameter. Two benches have similar size class frequency distributions but a third has significantly smaller trees. Recruitment on benches is episodic, may occur in areas open to grazing and is dependent on favourable conditions that allow tree survival. These favourable conditions include high seed availability, low levels of competition, deposition of fine sediments and adequate moisture for tree growth. Although C. cunninghamiana germinates on bars, seedlings are eliminated by prolonged inundation or flood scour and do not reach maturity. Recurring catastrophic floods or a sequence of large floods in rapid succession episodically destroy benches by substantial channel widening and initiate a new phase of bar and bench development. A conceptual model of the conversion of point bars to benches by thick mud deposition and C. cunninghamiana recruitment has been developed for sand‐bed streams draining similar sandstone catchments. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Deriving effects of pressure depletion on elastic framework moduli from sonic logs     

Anne-Kari Furre  Mona Andersen  Anita Smalø Moen  Randi Kristin Tønnessen 《Geophysical Prospecting》2009,57(3):427-437

We have developed a method to determine the effect of pore pressure depletion on elastic framework moduli, by utilizing sonic logs from wells drilled at different locations through a reservoir at varying depletion stages. This is done by first inverting the sonic logs for elastic framework bulk and shear moduli, thus carefully removing pressure dependent fluid effects. By crossplotting these elastic framework moduli against an increase in net stress (which is directly related to depletion), we derive the stress sensitivity of the elastic framework moduli. We found that the observed stress sensitivity was consistent with time-lapse seismic results and that the sensitivity derived from the sonic logs was much smaller than predicted by hydrostatic measurements on core samples. This method is applicable to depletion scenarios in mature fields and can be used both for modelling and inverting time-lapse seismic data for effects of pore pressure depletion on seismic data.  相似文献   

Retention of mercury in sediments of the Baltic Sea near Oulu,Finland     

Kimmo Tolonen  Erkki Alasaarela  Anita Liehu 《Journal of Paleolimnology》1988,1(2):133-140

Several cores were compared to elucidate the grade of mercury retention in sediments of the Baltic Sea near Oulu, Finland. The known history of the mercury discharge to waste water from a chlor-alkali plant, the primary pollution source, was compared to that in the sedimentary record. One core was dated by lead-210 and varve counts. During the past thirty years, the rate of sedimentation was up to 10 mm per year corresponding to a dry matter accumulation rate of about 3 kg m^–2a^–1. Under these conditions, most of the mercury reaching the sediment was retained. Correspondingly, the mercury levels in fish were considerably lower, with a delay of some five years.The present mercury content of the upper layers is some 1/4 or 1/5 that of the late 1970's, but it is still some twentyfold compared to levels at the beginning of the century. The extent to which the present mercury level in the sediment represents the various phases of industrial emission remains unsolved due to the origin of mercury in this sea area from several other sources and due to difficulties in exact core correlations from different years.  相似文献   

Spectroscopic diagnostics for N III ion     

B. N. Dwivedi  Anita Mohan  A. K. Gupta 《Astrophysics and Space Science》1996,243(1):163-163

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