Monitoring land surface and cover in urban and peri-urban environments using digital aerial photography     

Peter Caccetta  Simon Collings  Andrew Devereux  Kassell Hingee  Don McFarlane  Anthony Traylen 《International Journal of Digital Earth》2016,9(5):457-475

This paper describes the development of a system for decimetre-scale monitoring of land-surface and land-cover in urban and peri-urban environments. We describe our methodology that comprises the application of highly automated processing and analysis methods to digital aerial photography. The approach described in this paper addresses a monitoring need by providing the ability to generate change information at a spatial resolution suitable for urban, peri-urban and coastal areas, where an increasing percentage of the worlds’ population dwells. These areas are dynamic, with many environmental issues associated with planning, service provision, resource management and allocation, as well as monitoring regulatory compliance. We present a system based on standardised data and methods, which is able to track and communicate changes in features of interest in a way that has not been previously possible. We describe the methodology and then demonstrate its feasibility by applying it to geographic areas of planning and policy relevant size (the order of tens of thousands of square kilometres). We demonstrate the approach by applying it to the problem of urban forest assessment.  相似文献   

Mobilization of aluminium in the wathering profiles of the African surface in Malawi     

M. J. McFarlane  D. J. Bowden 《地球表面变化过程与地形》1992,17(8):789-805

Leaching of aluminium from the weathering profile of the African surface in Malawi was deduced from the chemistry of a vadose profile. Its loss occurs where congruent kaolinite dissolution results in saprolite collapse, leaving a weakly lateritized, sandy residual mantle. This leaching is a contemporary process, as shown by the precipitation of aluminosilicate evaporites in the dambos (seasonally waterlogged bottomlands). This paper presents the results of determinations, by ICP-OES and AAS-graphite furnace, of aluminium levels in groundwaters, examining the effects of a variety of pretreatments. Filtration (0.45 μm) substantially reduces the levels of total aluminium, showing it to be in particulate form. Subsequent acidification causes precipitation of < 0.45 μm forms of aluminium, further reducing the apparent levels to below ICP-OES detection limit. This is consistent with mobilization in organically bound forms which are destabilized at low pH, and accords with earlier work which showed that indigenous micro-organisms can cause dissolution of kaolinite. Organically bound mobilization provides an explanation for aluminium leaching at near-neutral pH in conjunction with the presence of silica in solution. The identification of this mechanism of kaolinite dissolution and aluminium evacuation from vadose profiles provides a realistic process for the levelling of extensive planation surfaces; the contingent collapse of the kaolinized saprolite would lower the interfluves, progressively narrowing the vadose zone until the landsurface approaches the planar form of the stable, regional water-table.  相似文献   

Magnetic components contributing to the NRM of Middle Siwalik red beds     

Lisa Tauxe  Dennis V. Kent  Neil D. Opdyke 《Earth and Planetary Science Letters》1980,47(2):279-284

The components of the NRM in Middle Siwalik red beds are carried by two phases of hematite, a red pigment phase and a specular hematite phase. We present evidence in the form of a conglomerate test that the specularite phase carries a remanence acquired during or shortly after deposition. The red pigment, however, post-dates deposition, in many cases by at least one reversal boundary. This secondary component has a higher coercivity but a lower blocking temperature in these rocks and can therefore be selectively removed by thermal demagnetization to reveal a primary magnetization useful for magnetostratigraphic studies.  相似文献   

Variability of precipitation intensity: sensitivity to treatment of moist convection in an RCM and a GCM     

Virginie Lorant  Norman A. McFarlane  John F. Scinocca 《Climate Dynamics》2006,26(2-3):183-200

The present study investigates the sensitivity of the frequency distribution of precipitation rates to the closure employed in the penetrative mass flux cumulus parameterization of Zhang and McFarlane in the Canadian regional climate model (CRCM) and in the Canadian Centre for Climate Modelling and Analysis third generation global atmospheric general circulation model (AGCM3). The effects of an alternative prognostic closure for mass flux cumulus parameterization in place of the original diagnostic closure are investigated. A set of experiments is performed in which changes in the frequency distribution of precipitation rates and cloud base mass-flux are examined as a function of the parameters that define each closure scheme. The relationship between the frequency distribution of precipitation and cloud base mass flux is examined and a self-consistent relation is found when the depth of convection is taken into account. Experiments performed with the prognostic closure favor relatively strong cloud base mass-flux and deep penetrative convection with relatively more intense convective precipitation. The mean of the frequency distribution of convective precipitation is larger and the heavier events become more intense. Also, experiments performed with the prognostic closure favor less frequent convective activity. However these changes in the distribution of convective component of precipitation are generally offset by opposite changes in the distribution of the resolved large-scale component of precipitation, resulting in relatively smaller changes in total precipitation. The altered partition of precipitation between convective and large-scale components is found to alter the energy balance and the thermodynamic equilibrium structure of the troposphere. The robustness found in the CRCM results regarding the sensitivity of the frequency distribution of precipitation to changes in the closure of the deep convection parameterization is investigated by performing a similar analysis of AGCM3 simulations. A remarkable similarity of AGCM3 and CRCM results is found suggesting that the closure sensitivity identified in this study is robust.  相似文献   

Vulnerability of Hampton Roads,Virginia to Storm-Surge Flooding and Sea-Level Rise   总被引：9，自引：1，他引：9  

Lisa R. Kleinosky  Brent Yarnal  Ann Fisher 《Natural Hazards》2007,40(1):43-70

Sea-level rise will increase the area covered by hurricane storm surges in coastal zones. This research assesses how patterns of vulnerability to storm-surge flooding could change in Hampton Roads, Virginia as a result of sea-level rise. Physical exposure to storm-surge flooding is mapped for all categories of hurricane, both for present sea level and for future sea-level rise. The locations of vulnerable sub-populations are determined through an analysis and mapping of socioeconomic characteristics commonly associated with vulnerability to environmental hazards and are compared to the flood-risk exposure zones. Scenarios are also developed that address uncertainties regarding future population growth and distribution. The results show that hurricane storm surge presents a significant hazard to Hampton Roads today, especially to the most vulnerable inhabitants of the region. In addition, future sea-level rise, population growth, and poorly planned development will increase the risk of storm-surge flooding, especially for vulnerable people, thus suggesting that planning should steer development away from low-lying coastal and near-coastal zones.  相似文献   

Characteristics of magnetite in submarine basaltic glass   总被引：1，自引：0，他引：1  

Thomas Pick  Lisa Tauxe 《Geophysical Journal International》1994,119(1):116-128

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Environmental and socioeconomic dynamics of the Indian Ocean tsunami in Penang,Malaysia     

Benjamin Horton  Michael Bird  Thomas Birkland  Susan Cowie  Ong Jin Eong  Andrea Hawkes  Gong Wooi Khoon  Lisa Law  Colin Macgregor  Aileen Tan Shau‐Hwai  Teh Tiong Sa  Zulfigar Yasin 《Singapore journal of tropical geography》2008,29(3):307-324

This paper addresses some of the environmental and socioeconomic dimensions of the 2004 Indian Ocean tsunami on Penang, Malaysia. We aim to offer wide access to unique and perishable data, while at the same time providing insight to ongoing debates about hazards, vulnerability and social capital. Our social survey examines some of the dynamics that shaped the tsunami impact, response and recovery process. While in terms of lives lost Penang may not conform to arguments surrounding vulnerable environments, the recovery process is more marked by social disparities in terms of the ability to access resources. Our physical survey records local topography, flow depth and flow direction, and charts the differential impact of the tsunami. Yet measuring hazards is not a straightforward process, and relies on reflexive methodologies and eyewitness accounts.  相似文献   

广东河源断裂带地热成因及与构造关系初探   总被引：2，自引：2，他引：0  

Lisa TANNOCK  王亚  李景富  刘洁  张珂  徐力峰  Klaus REGENAUER-LIEB 《地质力学学报》2019,25(3):400-411

广东省河源断裂带位于中国东南沿海地热异常区,地热资源十分丰富,但其形成机制和利用前景尚不确定。为此文章开展了多学科综合分析,获得以下初步认识:温泉是断裂带内深循环地下水被地温加热而成,断裂剪切热和花岗岩浆残余热的贡献基本可以排除;沿断裂展布的厚层硅化带是古水热活动的产物;硅化带形成时期的挤压应力方向为北东-南西,与河源断裂及河源盆地晚白垩世以来的伸展活动对应,现代构造应力场为北西西-南东东方向挤压,与古应力场相比发生了明显变化;现今构造应力场使得北东向河源断裂呈右旋挤压运动,而北西向断裂则发生左旋张剪,导致地下水循环格局也发生相应改变;目前温泉沿河源断裂呈带分布,沿北西向断裂呈线性溢出,断裂交汇部位是热泉上升的主要通道。总体而言,河源地区拥有令人鼓舞的地热资源及应用前景,有可能达到建设地热发电厂的目标。建议继续深入开展地质学、地球物理、水文地质学和地热成因机理等多学科综合研究,从而更好地定量评价地热潜能与开发前景。  相似文献   

The role of rock surface hardness and internal moisture in tafoni development in sandstone     

Lisa Mol  Heather A. Viles 《地球表面变化过程与地形》2012,37(3):301-314

The development of cavernous weathering features such as tafoni remains poorly understood. In particular, the roles played by internal moisture and case hardening remain unclear. In this study, Electric Resistivity Tomography (ERT) has been used to map moisture distribution within inner walls of tafoni developed in sandstone, and an Equotip device used to measure rock surface hardness as a proxy measure of the degree of weathering and case hardening. Seven large tafoni in the Golden Gate Highlands National Park (South Africa), varying in size and degree of development have been monitored. A dynamic relationship between surface hardness, degree of weathering and internal moisture regimes has been found. We propose a new conceptual model which illustrates the complex interaction between case hardening and internal moisture and suggests a new direction for cavernous weathering research. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

New metrics for managing and sustaining the ocean's bounty     

Heather Tallis  Sarah E. LesterMary Ruckelshaus  Mark PlummerKaren McLeod  Anne GuerrySandy Andelman  Margaret R. CaldwellMarc Conte  Stephen CoppsDavid Fox  Rod FujitaSteven D. Gaines  Guy GelfenbaumBarry Gold  Peter KareivaChoong-ki Kim  Kai LeeMichael Papenfus  Scott RedmanBrian Silliman  Lisa WaingerCrow White 《Marine Policy》2012,36(1):303-306

Policies are arising around the world, most recently in the United States, that mandate the implementation of marine spatial planning as a practical pathway towards ecosystem-based management. In the new United States ocean policy, and several other cases around the globe, ecosystem services are at the core of marine spatial planning, but there is little guidance on how ecosystem services should be measured, making it hard to implement this new approach. A new framework is shown here for practical, rigorous ecosystem service measurement that highlights contributions from both natural and social systems. The novel three-step framework addresses traditional shortcomings of an ecosystem services approach by giving managers and scientists the tools to assess and track: (1) the condition of the ecosystem (supply metrics), (2) the amount of ocean resources actually used or enjoyed by people (service metrics), and (3) people's preference for that level of service (value metrics). This framework will allow real world progress on marine spatial planning to happen quickly, and with a greater chance for success.  相似文献