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211.
Clare M. Robertson Martin S. Brook Kat A. Holt Ian C. Fuller Douglas I. Benn 《New Zealand geographer》2013,69(1):14-25
Hooker Glacier in the central Southern Alps of New Zealand has undergone significant downwasting and recession (~2.14 km) during the last two centuries. High retreat rates (51 m a?1 1986–2001, 43 m a?1 2001–2011) have produced a large (1.22 km2) proglacial lake. We present a retreat scenario for Hooker Glacier. A retreat scenario predicts that the glacier terminus will stabilise >3 km up‐valley of the current lake outlet after 2028 when ice velocity equals calving rate. 相似文献
212.
Trevor Fuller PhD student 《The Professional geographer》2013,65(2):272-274
A relatively simple modeling approach for estimating spatially distributed surface energy fluxes was applied to two small watersheds, one in a semi-arid climate region and one in a sub-humid region. This approach utilized a combination of ground-based meteorological data and remotely sensed data to estimate ‘instantaneous’ surface energy fluxes at the time of the satellite or aircraft overpasses. The spatial resolution in the watershed grid cells, which was on the order of 100-400 km, was selected to be compatible with ground measurements used for validation. The model estimates of surface energy fluxes compared well with ground-based measurements of surface flux (typically within approximately 40 Wm?2). The model accuracy may be slightly less for bare soil surfaces due to an overestimation of the soil heat flux. In addition to demonstrating the feasibility of computing spatially distributed values of surface energy fluxes, these maps were used to qualitatively infer the dominant factors controlling the energy fluxes for the time period shortly following precipitation events in the basins. For the semi-arid watershed, values of sensible heat flux varied considerably over the watershed and displayed a pattern very similar to that of the spatially variable cumulative precipitation for at least one to eight days prior to the image acquisition. Due to the large fraction of exposed bare soil in a semi-arid ecosystem, even very small precipitation events had a strong influence on the pattern of sensible heat fluxes observed shortly after the event (less than 24 hours). For the sub-humid watershed, the fluxes tended to be more uniform across the watershed, and were influenced by a combination of precipitation total and land cover type. 相似文献
213.
214.
Daniel Brown Keiko Saito Meng Liu Robin Spence Emily So Michael Ramage 《Bulletin of Earthquake Engineering》2012,10(3):741-764
The M7.9 Wenchuan earthquake on May 12th, 2008 was the most destructive in China since 1976. The event caused huge damage and loss of life and exposed weaknesses both in the formulation and implementation of the regulations governing building in the affected provinces. Following the earthquake a massive relief and recovery operation was mounted by the Chinese government. The authors took part in field studies in the affected area which took place 5 and 11?months after the event, at which time recovery operations were well-advanced. The aims of the study were to assess the effects caused by the earthquake to the built environment and society, to collect information on the ongoing recovery efforts and future plans, and to demonstrate the use of tools that allow the collection of spatially referenced damage and recovery data. Based on available satellite imagery supplemented by ground observation, geodatabases were constructed containing information on damage and recovery in several parts of the affected area. The paper gives an overview of the recovery process, describes the methods used to construct these geodatabases, and offers some analysis of the data obtained. It is argued that such databases have great potential for the management of post-disaster recovery and for creating a permanent record of the recovery process. 相似文献
215.
216.
Heather L. Purdie Martin S. Brook Ian C. Fuller John Appleby 《New Zealand geographer》2008,64(1):5-19
Abstract: Seasonal variations in ablation and surface velocity were investigated on the lower Fox Glacier. Variations occur between summer and winter ablation, with surface velocity also showing marked seasonality. Recent advance has resulted in the glacier gaining around 200 m length since late 2004. Longer term, Fox Glacier appears linked to the Southern Oscillation Index, with positive glacier mass balances associated with negative Southern Oscillation Index (El Niño). An estimated glacier response time of approximately 9–14 years suggests the current terminus advance was linked to mass gains in the mid-1990s. Recent collapses at the terminal face continue to prove a hazard at this busy tourist destination. 相似文献
217.
A technique is described for obtaining rapid high‐quality silhouette photographs of plankton samples at sea. This technique was designed to facilitate identification and enumeration of pelagic marine fish eggs in near real‐time. It uses readily available photographic materials and unlike previously described techniques, the silhouettes are recorded directly on to photographic paper rather than film. The resolution is adequate for microscopic measurements. Examples are presented from a cruise off Westland, New Zealand, which investigated the distribution of hoki eggs. 相似文献
218.
Interfacial interactions, namely interfacial tension, wettability, capillarity and interfacial mass transfer are known to govern fluid distribution and behavior in porous media. Therefore the interfacial interactions between CO2, brine and oil and/or gas reservoirs have a significant influence on the effectiveness of any CO2 storage operations. However, data and knowledge of interfacial properties in storage conditions are scarce. This issue becomes particularly true in the case of deep saline aquifers where limited, economically driven, data collection and archiving are available. In this paper, we present a complete set of brine–CO2 interfacial tension data at pressure, temperature and salinity conditions, representative of a CO2 storage operation. A semi-empirical correlation is proposed to calculate the interfacial tension from the experimental data. Wettability is studied at pore scale, using glass micromodels in order to track fluids distribution as a function of the thermodynamic properties and wettability conditions for water–CO2 systems. With this approach, we show that, in strongly hydrophilic porous media, the CO2 does not wet the solid surface whereas; if the porous media has less hydrophilic properties the CO2 significantly wets the surface. 相似文献
219.
Benjamin Bernard Silvana Hidalgo Claude Robin Bernardo Beate Jenny Quijozaca 《Bulletin of Volcanology》2014,76(9):1-20
Based on geochronological, petrological, stratigraphical, and sedimentological data, this paper describes the deposits left by the most powerful Holocene eruption of Chachimbiro compound volcano, in the northern part of Ecuador. The eruption, dated between 3640 and 3510 years BC, extruded a ~650-m-wide and ~225-m-high rhyodacite dome, located 6.3 km east of the central vent, that exploded and produced a large pyroclastic density current (PDC) directed to the southeast followed by a sub-Plinian eruptive column drifted by the wind to the west. The PDC deposit comprises two main layers. The lower layer (L1) is massive, typically coarse-grained and fines-depleted, with abundant dense juvenile fragments from the outgassed dome crust. The upper layer (L2) consists of stratified coarse ash and lapilli laminae, with juvenile clasts showing a wide density range (0.7–2.6 g cm?3). The thickness of the whole deposit ranges from few decimeters on the hills to several meters in the valleys. Deposits extending across six valleys perpendicular to the flow direction allowed us to determine a minimum velocity of 120 m s?1. These characteristics show striking similarities with deposits of high-energy turbulent stratified currents and in particular directed blasts. The explosion destroyed most of the dome built during the eruption. Subsequently, the sub-Plinian phase left a decimeter-thick accidental-fragment-rich pumice layer in the Chachimbiro highlands. Juvenile clasts, rhyodacitic in composition (SiO2?=?68.3 wt%), represent the most differentiated magma of Chachimbiro volcano. Magma processes occurred at two different depths (~14.4 and 8.0 km). The hot (~936 °C) deep reservoir fed the central vent while the shallow reservoir (~858 °C) had an independent evolution, probably controlled by El Angel regional fault system. Such destructive eruptions, related to peripheral domes, are of critical importance for hazard assessment in large silicic volcanic complexes such as those forming the Frontal Volcanic Arc of Ecuador and Colombia. 相似文献
220.
Maganti Janardhana P. Robin Davis S. S. Ravichandran A. M. Prasad D. Menon 《地震工程与工程振动(英文版)》2014,13(2):347-355
Glass fi ber reinforced gypsum(GFRG) wall panels are prefabricated panels with hollow cores, originally developed in Australia and subsequently adopted by India and China for use in buildings. This paper discusses identifi cation and calibration of a suitable hysteretic model for GFRG wall panels fi lled with reinforced concrete. As considerable pinching was observed in the experimental results, a suitable hysteretic model with pinched hysteretic rule is used to conduct a series of quasi-static as inelastic hysteretic response analyses of GFRG panels with two different widths. The calibration of the pinching model parameters was carried out to approximately match the simulated and experimental responses up to 80% of the peak load in the post peak region. Interestingly, the same values of various parameters(energy dissipation and pinching related parameters) were obtained for all fi ve test specimens. 相似文献