新30井不同深度下的水温观测试验及其结果

本文通过在新30号观测井孔里重新放置一套新的测温仪, 使新、 老水温监测仪在不同深度同时观测, 发现在同一井孔中, 不同深度的水温探头所记录到的井水温度变化曲线形态是不一样的, 也就是观测井放置探头的深度与部位对井水温观测结果有明显的影响。 通过对新30井水温试验仪观测数据分析, 可以确定探头放置180～185 m处, 水温日变化有规律, 有潮汐显示, 而且与同井观测的井水位在日变形态上具有一定的同步性, 表现为水位上升时水温上升, 水位下降时水温也下降。 另外, 分析了该井水温探头在不同深度的日变形态和映震灵敏度, 并初步确定该井放置水温探头较为合理的观测深度为180 m。     

The New Zealand Coastal Society: What does it do and who is it for?

Abstract:   This article briefly outlines the aims and activities of the New Zealand Coastal Society, a technical interest group formed in 1992. It explains the history of the society, who its members are, and addresses the question of who would benefit from joining the society.     

Multi-decadal coastal change in New Zealand: Evidence, mechanisms and implications

Abstract:   Coastal research and monitoring on New Zealand beaches have typically examined seasonal and event-driven (storms) changes in the coast. However, historical records are now of sufficient length to indicate that change occurs at longer timescales. This paper presents examples of multi-decadal change at three case-study locations around New Zealand. Results show that morphological adjustment of the coast occurs at multi-decadal scales and is much larger than short-term dynamics. Physical mechanisms driving changes are ill defined but may be associated with El Niños and La Niña episodes which modulate waves and sea level, as well as changes in sediment supply.     

Geographical reflections on Sir Edmund Hillary (1919–2008)

Abstract: During the past year, the media, public and officialdom have focused on Sir Edmund Hillary, his achievements, and what they mean to New Zealand. In this commentary, we reflect on how they relate to human geography. Although we acknowledge the obvious tensions that exist between adventuring and the contemporary concerns of the discipline, we also illustrate how Hillary's life and actions resonate with many of the discipline's current hopes, aims and challenges. Specifically, we discuss thematic overlaps in the fields of geopolitics and national identities, colonial histories and resistances, as well as the emerging public geography. We posit that ‘Hillary's geography’ is closer to human geography than is realized or at least acknowledged by geographers.     

Trajectories of protection: Protectorates of Aborigines in early 19th century Australia and Aotearoa New Zealand

Abstract: This article tracks the passage of Aboriginal protection, as a contested imperial institution, from the Caribbean to Australia and Aotearoa New Zealand via the Cape Colony and Britain. In doing so, it reconfigures the historical geographies of colonial philanthropy, and of those individuals who sought to implement and resist it, as a set of specific, intersecting trajectories. These trajectories, of people, ideas and texts, both connected and remade multiple colonial places. The article also advocates positioning the contemporary politics of the colonial past in Britain, Australia and Aotearoa New Zealand, within a wider, trans‐imperial, set of connections.     

2011年新西兰Mw6.1地震震源过程及强地面运动特征初步分析

2011年2月21日新西兰南岛发生M_w6.1地震,震中位置43.58°S,172.70°E,震源深度约5.0 km,发震断层为新西兰第三大城市克赖斯特彻奇(Christchurch)南约9 km一条近东西走向的未知隐伏断层,为逆冲断层机制.地震已经造成163人遇难,Christchurch城内多处建筑物严重损毁,距震中约1 km的Heathcote Valley Primary School (HVSC)台站强地面运动峰值加速度(PGA)高达2.0g.针对新西兰M_w6.1地震近场强地面运动偏高这一现象,利用HVSC台站的强震观测记录,计算地震震源谱参数,应用Brune圆盘模型估算其近场强地面运动的理论值,并建立动态复合震源模型进行模拟计算.研究结果表明,新西兰M_w6.1地震近断层强地面运动偏高的主要原因为复杂震源破裂过程中有效应力降(动态应力降,Δσ_d)过高造成的.未来工作中,需要加强对可能发生的、距离城市较近的中小型地震的重视,防止地震对城市的加强型破坏.     

The effect of submerged plateaux on Pleistocene gyral circulation and sea-surface temperatures in the Southwest Pacific

Uniquely in the Southern Hemisphere the New Zealand micro-continent spans the interface between a subtropical gyre and the Subantarctic Circumpolar Current. Its 20° latitudinal extent includes a complex of submerged plateaux, ridges, saddles and basins which, in the present interglacial, are partial barriers to circulation and steer the Subtropical (STF) and Subantarctic (SAF) fronts. This configuration offers a singular opportunity to assess the influence of bottom topography on oceanic circulation through Pleistocene glacial – interglacial (G/I) cycles, its effect on the location and strength of the fronts, and its ability to generate significant differences in mixed layer thermal history over short distances.For this study we use new planktic foraminiferal based sea-surface temperature (SST) estimates spanning the past 1 million years from a latitudinal transect of four deep ocean drilling sites. We conclude that: 1. the effect of the New Zealand landmass was to deflect the water masses south around the bathymetric impediments; 2. the effect of a shallow submerged ridge on the down-current side (Chatham Rise), was to dynamically trap the STF along its crest, in stark contrast to the usual glacial–interglacial (G–I) meridional migration that occurs in the open ocean; 3. the effect of more deeply submerged, downstream plateaux (Campbell, Bounty) was to dynamically trap the SAF along its steep southeastern margin; 4. the effects of saddles across the submarine plateaux was to facilitate the development of jets of subtropical and subantarctic surface water through the fronts, forming localized downstream gyres or eddies during different phases in the G–I climate cycles; 5. the deep Pukaki Saddle across the Campbell-Bounty Plateaux guided a branch of the SAF to flow northwards during each glacial, to form a strong gyre of circumpolar surface water in the Bounty Trough, especially during the mid-Pleistocene Climate Transition (MIS 22-16) when exceptionally high SST gradients existed across the STF; 6. the shallower Mernoo Saddle, at the western end of the Chatham Rise, provided a conduit for subtropical water to jet southwards across the STF in the warmest interglacial peaks (MIS 11, 5.5) and for subantarctic water to flow northwards during glacials; 7. although subtropical or subantarctic drivers can prevail at a particular phase of a G–I cycles, it appears that the Antarctic Circumpolar Current is the main influence on the regional hydrography.Thus complex submarine topography can affect distinct differences in the climate records over short distances with implications for using such records in interpreting global or regional trends. Conversely, the local topography can amplify the paleoclimate record in different ways in different places, thus enhancing its value for the study of more minor paleoceanographic influences that elsewhere are more difficult to detect. Such sites include DSDP 594, which like some other Southern Ocean sites, has the typical late Pleistocene asymmetrical saw-tooth G–I climate pattern transformed to a gap-tooth pattern of quasi-symmetrical interglacial spikes that interrupt extended periods of minimum glacial temperatures.     

Identification of larvae of snapper Chrysophrys auratus forster by electrophoretic separation of tissue enzymes (note)

A comparison was made between the electrophoretic patterns of isozymes of esterases and glucosephosphate isomerases of adult snapper Chryosophrys auratus, suspected snapper larvae, jack mackerel Trachurus novaezelandiae larvae, and blue mackerel Scomber australasicus larvae. The suspected snapper larvae revealed similar isozyme patterns to those of the adults, but differed from the other two larval species.     

How much runoff do riparian wetlands affect?

Abstract

Nitrate runoff from pastoral fanning is of concern because it contributes to lake eutrophication. Surface flow in wetlands is a measure of the runoff likely to experience nitrate attenuation. This study assessed the potential of small headwater wetlands to reduce catchment nitrate loads by quantifying the proportion of total runoff that occurred as surface flow at the outlet of wetlands. Surface flow can be measured from wetlands in side valleys (valley wetlands) with well defined flow channels, but not in those parallel to the stream (riparian wetlands) with distributed flow. This study, from November 2004 to June 2008: (1) measured the mean specific flow yield (mm yr^?1) at the outlet of 6 wetlands; (2) classified wetlands into 3 types based on hydrology; (3) mapped and classified all wetlands in the catchment; and (4) calculated the area‐weighted mean specific yield of wetlands for the whole catchment. The 6.6 km² study catchment at Taupo, North Island, New Zealand, was predominantly pasture on volcanic soils where flows were baseflow dominated. Riparian and valley wetlands occupied 5% of catchment area. Type 1 wetlands flowed continuously, were dominated by baseflow (81–83%), and had a mean annual yield (± SE) of 167 ± 46 mm (34% of stream yield). Type 2 wetlands dried up during droughts and type 3 wetlands dried up each summer. Both latter types had a low baseflow component (20%) and a yield of 66±18 mm (13% of stream yield). In one tributary, gaugings over 4 days in summer during a wet year indicated that 27% of streamflow originated from wetlands. For the catchment as a whole, wetland baseflow accounted for 11± 4% of mean annual streamflow and wetland quickflow another 8 ± 2%, although these percentages are likely underestimates because seepages occurred downslope from measurement points. Although riparian and valley wetlands occupied only 5% of the catchment area, they could potentially have attenuated nitrogen in 11–19% of runoff. Other catchments may have different hydrology and wetland nitrate attenuation, and the methods outlined here could be used to quantify these differences.     

Sediment remobilisation from decomposing cordgrass (Spartina anglica) patches on a wave‐exposed intertidal flat

Abstract

Concerns about the potential adverse effects of Spartina invasion on New Zealand estuaries, such as habitat loss and degradation, have led to herbicide use to control its spread. An experiment was conducted in the Manukau Harbour (New Zealand) to determine sediment remobilisation rates (?E) from herbicide‐treated S. anglica patches. Paired treatment and control patches (≤25 m diam.) were monitored at two sites 500 m apart with different wave exposures. Above‐ (AGB) and below‐ground (BGB) biomass decomposition and AE were determined from repeat surveys over c. 2.5 years. Work done by waves (W), which integrates wave‐energy dissipation at the bed over time, was used as a surrogate measure of sediment transport potential. Complete AGB loss occurred in both treated patches within 3 months of initial herbicide application, whereas BGB (a matrix of roots and rhizomes) persisted much longer. An exponential decay model (r ² = 0.6) fitted to the site‐two treatment data predicted an c. 85% reduction in BGB after 5 years, whereas the BGB changes for the larger and more heterogeneous site‐one treatment were more complex. BGB was a better predictor of average bed elevation than AGB in multiple regression models and, although bed elevation decreased through time and with waves, BGB was positively related to bed elevation at both sites. AE was similar for both treatment patches (c. 0.05 and c. 0.06 m yr^‐1, P < 0.001, r² ≥ 0.97) and complete sediment loss was predicted to occur within 6–10 years. The site‐one control patch accumulated sediment (0.01 m yr^‐1 , P < 0.001, r ² = 0.81) whereas the more wave‐exposed site‐two control eroded (0.01 m yr^‐1, P = 0.0017, r ² = 0.61). The potential for adverse sediment effects resulting from Spartina control at wave‐exposed sites will be minimal if the treated areas are small relative to the size of the estuary.