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41.
Systems for Hazards Identification in High Mountain Areas: An Example from the Kullu District, Western Himalaya 总被引:2,自引:1,他引:1
JamesS.Gardner EricSaczuk 《山地科学学报》2004,1(2):115-127
Methods and techniques for the identification, monitoring and management of natural hazards in high mountain areas are enumerated and described. A case study from the western Himalayan Kullu District in Himachal Pradesh, India is used to illustrate some of the methods. Research on the general topic has been conducted over three decades and that in the Kullu District has been carried out since 1994. Early methods of hazards identification in high mountain areas involved intensive and lengthy fieldwork and mapping with primary reliance on interpretation of landforms, sediments and vegetation thought to be indicative of slope fail ures, rock falls, debris flows, floods and accelerated soil surface erosion. Augmented by the use of airphotos and ad hoc observations of specific events over time, these methods resulted in the gradual accumulation of information on hazardous sites and the beginnings of a chronology of occurrences in an area. The use of historical methods applied to written and photographic material, often held in archives and libraries, further improved the resolution of hazards information. In the past two decades, both the need for, and the ability to, accurately identify potential hazards have increased. The need for accurate information and monitoring comes about as a result of rapid growth in population, settlements, transportation infrastructure and intensified land uses and, therefore, risk and vulnerability in mountain areas. Ability has improved as the traditional methods of gathering and manipulating data have been supplemented by the use of remotesensing, automated terrain modeling, global positioning systems and geographical information systems. This paper focuses on the development and application of the latter methods and techniques to characterize and monitor hazards in high mountain areas. 相似文献
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43.
Barry H. Lynn Cynthia Rosenzweig Richard Goldberg David Rind Christian Hogrefe Len Druyan Richard Healy Jimy Dudhia Joyce Rosenthal Patrick Kinney 《Climatic change》2010,99(3-4):567-587
The Mesoscale Modeling System Version 5 (MM5) was one-way nested to the Goddard Institute for Space Studies global climate model (GISS GCM), which provided the boundary conditions for present (1990s) and future (IPCC SRES A2 scenario, 2050s) five-summer “time-slice” simulations over the continental and eastern United States. Five configurations for planetary boundary layer, cumulus parameterization, and radiation scheme were tested, and one set was selected for use in the New York City Climate and Health Project—a multi-disciplinary study investigating the effects of climate change and land-use change on human health in the New York metropolitan region. Although hourly and daily data were used in the health project, in this paper we focus on long-term current and projected mean climate change. The GISS-MM5 was very sensitive to the choice of cumulus parameterization and planetary boundary layer scheme, leading to significantly different temperature and precipitation outcomes for the 1990s. These differences can be linked to precipitation type (convective vs. non-convective), to their effect on solar radiation received at the ground, and ultimately to surface temperature. The projected changes in climate (2050s minus 1990s) were not as sensitive to choice of model physics combination. The range of the projected surface temperature changes at a given grid point among the model versions was much less than the mean change for all five model configurations, indicating relative consensus for simulating surface temperature changes among the different model projections. The MM5 versions, however, offer less consensus regarding 1990s to 2050s changes in precipitation amounts. All of the projected 2050s temperature changes were found to be significant at the 95th percent confidence interval, while the majority of the precipitation changes were not. 相似文献
44.
Benjamin Gardner 《Geoforum》2009,40(5):781-783
Rather than making a uniform case for understanding the neoliberalization of ranching and pastoralism, the articles in this volume show how everyday practices are made through historically and geographically specific struggles over the characteristics of production, exchange and rule, in which livestock play a particularly important role. Collectively, I believe the articles in this volume highlight the significant relationship between cattle and capitalism, and make a compelling argument that to understand the material implications of neoliberalism we need to pay more attention to livestock as an important and rapidly changing medium of livelihood production and accumulation strategy around the world. 相似文献
45.
Young Baek Son Wilford D. Gardner Alexey V. Mishonov Mary Jo Richardson 《Journal of Earth System Science》2009,118(1):1-10
Hydrographic data, including particulate organic carbon (POC) from the Northeastern Gulf of Mexico (NEGOM) study, were combined
with remotely-sensed SeaWiFS data to estimate POC concentration using principal component analysis (PCA). The spectral radiance
was extracted at each NEGOM station, digitized, and averaged. The mean value and spurious trends were removed from each spectrum.
De-trended data included six wavelengths at 58 stations. The correlation between the weighting factors of the first six eigenvectors
and POC concentration were applied using multiple linear regression. PCA algorithms based on the first three, four, and five
modes accounted for 90, 95, and 98% of total variance and yielded significant correlations with POC with R
2 = 0.89, 0.92, and 0.93. These full waveband approaches provided robust estimates of POC in various water types.
Three different analyses (root mean square error, mean ratio and standard deviation) showed similar error estimates, and suggest
that spectral variations in the modes defined by just the first four characteristic vectors are closely correlated with POC
concentration, resulting in only negligible loss of spectral information from additional modes. The use of POC algorithms
greatly increases the spatial and temporal resolution for interpreting POC cycling and can be extrapolated throughout and
perhaps beyond the area of shipboard sampling. 相似文献
46.
Ingrid Horák-Terra Antonio Martínez Cortizas Cynthia Fernandes Pinto Da Luz Alexandre Christófaro Silva Tim Mighall Plínio Barbosa De Camargo Carlos Victor Mendonça-Filho Paulo Eduardo De Oliveira Francisco Willian Cruz Pablo Vidal-Torrado 《第四纪科学杂志》2020,35(5):664-676
The late Quaternary evolution of central-eastern Brazil has been under-researched. Questions remain as to the origin of the Cerrado, a highly endangered biome, and other types of vegetation, such as the Capões – small vegetation islands of semi-deciduous and mountain forests. We investigated the factors that influenced the expansion and contraction of the Cerrado and Capões during the late Quaternary (last ~35 ka), using a multi-proxy approach: stable isotopes (δ13C, δ15N), geochemistry, pollen and multivariate statistics derived from a peat core (Pinheiro mire, Serra do Espinhaço Meridional). Five major shifts in precipitation, temperature, vegetation and landscape stability occurred at different timescales. Our study revealed that changes in the South Atlantic Convergence Zone (SACZ) seem to have been coeval with these shifts: from the Late Glacial Maximum to mid-Holocene the SACZ remained near (~29.6 to ~16.5k cal a bp ) and over (~16.5 to ~6.1 k cal a bp ) the study area, providing humidity to the region. This challenges previous research which suggested that climate was drier for this time period. At present, the Capões are likely to be a remnant of a more humid climate; meanwhile, the Cerrado biome seems to have stablished in the late Holocene, after ~3.1 k cal a bp . 相似文献
47.
Evolution of the Kivu Rift,East Africa: interplay among tectonics,sedimentation and magmatism 下载免费PDF全文
Douglas A. Wood Hubert J. Zal Christopher A. Scholz Cynthia J. Ebinger Irénée Nizere 《Basin Research》2017,29(Z1):175-188
The seismically and volcanically active Kivu Rift, in the western branch of the East African Rift System, is a type locale for studies of high‐elevation, humid‐climate rift basins, as well as magmatic basin development. Interpretations of offshore multi‐channel seismic (MCS) reflection data, terrestrial radar topography, lake bathymetry and seismicity data recorded on a temporary array provide new insights into the structure, stratigraphy and evolution of the Kivu rift. The Kivu rift is an asymmetric graben controlled on its west side by a ca. 110 km‐long, N‐S striking border fault. The southern basins of the lake and the upper Rusizi river basin are an accommodation zone effectively linking 1470 m‐high Lake Kivu to 770 m‐high Lake Tanganyika. MCS data in the eastern Kivu lake basin reveal a west‐dipping half graben with at least 1.5 km of sedimentary section; most of the ca. 2 km of extension in this sub‐basin is accommodated by the east‐dipping Iwawa normal fault, which bounds an intrabasinal horst. Lake Kivu experienced at least three periods of near desiccation. The two most recent of these approximately correlate to the African Megadrought and Last Glacial Maximum. There was a rapid lake level transgression of at least 400 m in the early Holocene. The line load of the Virunga volcanic chain enhances the fault‐controlled basin subsidence; simple elastic plate models suggest that the line load of the Virunga volcanic chain depresses the basin by more than 1 km, reduces flank uplift locally and broadens the depocentre. Not only do the voluminous magmatism and degassing to the lake pose a hazard to the riparian population, but our studies demonstrate that magmatism has important implications for short‐term processes such as lake levels, inflow and outlets, as well as long term modification of classic half‐graben basin morphology. 相似文献
48.
49.
休伦湖Saginaw湾沉积物反硝化率的测定及其时空特征 总被引:9,自引:2,他引:7
用N2生成法测定了北美休伦湖Saginaw湾1995年夏季7、8月份沉积物反硝化率,Saginaw湾内湾的沉积物反硝化率为16.0-39.6μmolN2/(m2·h),外湾沉积反硝化率为22.7 -26.1μmolN2/(m2·h),比较了不同湖泊沉积物反硝化率数值大小,指出休伦湖Saginaw湾水体现阶段的营养状况为贫-中营养水平.内外湾沉积物反硝化率数值波动大小与Saginaw河及休伦湖的影响有关;N2:TIN通量比值有不随采样时间的变化而变更等特性.在反硝化率测定过程中,反硝化率与O2消耗率之间有明显的正相关关系;沉积物上覆水中NH+4与NO-3之间通量值在变化趋势上有明显的负相关关系。 相似文献
50.
Variation in DOC and trace metal concentration along the heavily urbanized basin in Kathmandu Valley,Nepal 总被引:1,自引:0,他引:1
Water samples were analyzed for DOC and trace metals from Bagmati River within Kathmandu valley, Nepal, to understand the
variation trends of DOC and trace metals and their relationship along the drainage network. The variability in organic matter
and wastewater input within the Bagmati drainage basin appeared to control DOC and most of the trace metal concentration.
The large input of organic matter and wastewater creates anoxic condition by consuming dissolved oxygen and releasing higher
concentrations of DOC, trace elements such as nickel, arsenic, barium, cadmium, and copper with downstream distance. Concentrations
of DOC and trace metals like barium and zinc showed strong relationships with human population density and suggest that human
activities have strong control on these parameters along the drainage network. The DOC and most of the trace metal concentration
increased with downstream distance and appeared to be directly associated with human activities. The variation trends of most
of the trace metals appeared to be the same; however, concentration varied widely. Inputs of organic matter and wastewater
due to human activities appeared directly to be associated for the variation of DOC and trace metals along the Bagmati drainage
network within Kathmandu valley. 相似文献