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981.
982.
983.
A. M. Rusanov 《Russian Journal of Ecology》2012,43(1):33-39
Results are presented that have been obtained in studies on the effect of forests growing in the steppe zone on the conditions
of formation and qualitative and quantitative composition of organic matter and on the properties of humus in chernozem soils
of neighboring biogeocenoses. 相似文献
984.
Stormwater discharged from highly urbanised catchments on the southern shore of Sydney estuary, Australia, has been identified
as the primary source of contaminants responsible for ecological degradation and reduction in recreational value of the waterway.
Effective management of this pollution requires knowledge of contaminant loads associated with various stormwater flow conditions
in three highly urbanised catchments in Sydney estuary catchment. The majority (>90%) of metal (Cu, Pb and Zn) and total suspended
solid annual loads were contributed during high-flow conditions (>50 mm rainfall dayt1), whereas ≤55% of TN and ≤21% of total phosphorus were contributed to annual loading by dry weather base-flow conditions.
All flow conditions posed an in-stream ecological threat because contaminant concentrations exceeded water quality guidelines
for all analytes measured, except Pb. Irregular, temporal variability in contaminant concentrations associated with base-flow
(within day and amongst days), high-flow (amongst events) and irregular discharges indicated that contaminant contributions
in stormwater were strongly controlled by human activity in the three catchments. Significant variation in contaminant concentrations
under all flow conditions revealed unique chemical signatures for each catchment despite similarities in land uses, location
and geology amongst catchments. These characteristics indicate that assessment and management of stormwater pollution needs
to be conducted on an individual-catchment basis for highly urbanised regions of Sydney estuary catchment. 相似文献
985.
986.
987.
988.
Rapid urbanization in the developing world calls for attention to address the issue of urban sustainability, especially in emerging countries such as China, where social equity and environmental conditions have been marginalized by the rapid economic development. In this paper, we addressed the above issue with an attempt to answer the following questions: (1) How did the sustainability of Chinese cities evolve over time? (2) What are the driving forces for the evolution? By constructing a composite index that incorporates three major aspects of sustainability, economy, environment, and social equity, we characterized the recent evolution of Chinese cities and assessed the disparity among regions in terms of the sustainability measures. Further, we analyzed the driving forces for the change of sustainability indices through a driving force-pressure-state-effect model. We substantiate our numerical analysis of Chinese cities with a detailed case study of Urumqi, the capital of Xinjiang Autonomous Region, which has experienced significant change over the past 3 decades in every aspect of sustainability. We highlight some fundamental socioeconomic driving forces that have caused spatial restructuring, reflected by land-use change, and consequently impacted the urban environment of Urumqi. A brief case analysis of Guangzhou is also provided. 相似文献
989.
Richard C. Foltz 《Journal of Agricultural and Environmental Ethics》2007,20(6):533-542
990.
Quantification and reduction of erroneous differences between images in remote sensing 总被引:1,自引:0,他引:1
The reliability of image data, along with the difficulty of accurately comparing images acquired at different times or from
different sensors, is a generic problem in remote sensing. Measurement repeatability errors occur frequently and can substantially
reduce the system’s ability to reliably quantify real spectral and spatial change in a target. This paper outlines methodologies
for quantifying and reducing erroneous differences between monochrome and multispectral or hyperspectral images. [Each of
these image types is acquired by an instrument that collects light photons across a variable range of the electromagnetic
spectrum (often referred to as an image band). The hyperspectral image is often referred to as a hyperspectral cube with XY
spatial dimensions and many Z bands (spectral demotions)]. In this paper, we specifically discuss the Pixel Block Transform
(PBT), the Spectral Averaging Transform (SAT), and the Wavelet Transform (WAVEL). We briefly address sensor fusion. Results
indicate that the PBT is a powerful cross-noise and repeatability error reducing tool, applicable to monochrome, multispectral,
and hyperspectral images. The SAT is as powerful as the PBT in reducing error but is suitable only for hyperspectral imagery.
WAVEL can reduce some of the finer scale noise, but it is not as powerful in reducing cross-noise as PBT or SAT and it requires
some trial and error for selecting the appropriate wavelet function. It is important that those involved in developing statistically
sound relationships between remotely sensed imagery and other data sources understand the problems and their solutions to
prevent wasting time or developing relationships that are statistically insignificant or unstable, or that lead to faulty
conclusions. 相似文献