东南海岸带海相软土的Cc~n关系

收集整理了国内学者给出的我国东南海岸带不同地区（上海、连云港、广州、深圳、浙江沿海、渤海湾）海相沉积软土的8个Cc与n统计关系式,并根据公开发表的资料增加了这些地区以及沿海其他地区（天津、温州）260个的Cc～n数据,进行了东南海岸带软土的统一分析。发现Cc～n间存在较好的线性关系,具体关系大致可以分为陡变型和缓变型2类,缓变型与国外一些学者给出的统计结果较为接近。本文还对比了两种质量的上海软黏土的试验结果,分析了土样扰动对Cc～n统计关系的影响。     

换填黏性土料加固膨胀岩渠坡施工技术

南水北调中线一期工程总干渠新乡潞王坟膨胀岩试验段桩号SY0+208～SY0+268为换填黏性土料处理措施试验区。以试验段开挖出来的重粉质壤土作为换填黏性土料,通过振动凸块碾碾压来加固不同坡比的膨胀岩渠坡,重点研究换填黏性土料处理措施的施工工艺和施工控制标准。换填黏性土料加固膨胀岩渠坡的成功应用,证明以该处理措施处理膨胀岩渠坡的可行性,为南水北调中线一期工程总干渠膨胀岩渠坡的处理提供了参考。     

频率域航空电磁法浅层水资源调查的试验研究

用航空电磁法进行浅层水资源调查的试验研究,并取得显著成效,在我国还是首次。本文简述了该方法的地质、地球物理前提与技术条件。并指出,HDY-3型双频航空电磁系统,用中比例尺进行航测,在平原的“有咸水”水文地质分区中,圈定咸水、淡水、半咸水,是一种快速、经济而有效的新的水文物探手段。该方法不但能划分咸、淡水及半咸水的界线,还能预测淡水的相对富水程度、研究古沉积环境和土壤粒度。文中还讨论了充实和改进该方法的途径。     

Dynamics of seasonal recharge beneath a semiarid vegetation on the gnangara mound,Western Australia

To estimate seasonal changes in recharge to the underlying sandy aquifer, the soil water dynamics of the unsaturated zone was monitored down to a depth of 20 m over a period of three years (1985 to 1987). The measurements were made by a neutron probe at eight locations beneath a native vegetation in a semiarid region, Western Australia, receiving precipitation of 775 mm yr^?1. A relatively simple method, based on the analyses of sequentially measured soil water profiles involving utilization of zero flux plane in the unsaturated zone, is presented and used to compute seasonal recharge rates. Drainage fluxes (recharge rates) below two specified depths were estimated. These were: R₁ (water flux at a depth of 10 m, just below the maximum rooting depth) and R₂ (water flux at a depth of 18 m, just above the water table). These two estimates were significantly different both on a seasonal and annual basis, but their cumulative values for the three year period were very similar. While the annual precipitation varied from 525 to 850 mm yr^?1, the corresponding spatially averaged R₁ varied from 34 to 149 mm yr^?1, and R₂ varied from 65 to 80 mm yr^?1. A significant difference in recharge between the upslope and downslope positions on a hillslope was ascribed to differences in vegetation density of the understorey and differences in hydraulic properties of subsoils. For the three year period, the average R₁ and R₂ were 13 per cent and 10 per cent of the precipitation respectively. These values compare favourably with a long-term estimate based on an environmental tracer technique.     

Strong bursts and diffusion in avalanching systems

The connection between avalanche dynamics and space physics has been studied for several years. In that context we recently suggested an avalanche model which explains the phenomena of reconnection. In this work the model is generalized to include the influence of an extremely strong perturbation, reflecting the effect of plasma storms originating from the sun. In addition, we allow for diffusion processes and show that the behavior changes with the onset of diffusion processes, rendering it quasi-periodic, along with the supression of small-size avalanches.     

Sources and sinks of nutrients in a New Zealand hill pasture catchment I. Stormflow generation

The processes of stormflow generation were studied in a hill pasture catchment near Hamilton, New Zealand. Although rainfall was relatively evenly distributed throughout the year, stormflow was highly seasonal and over 65 per cent occurred during the winter. Three main processes contributing to stormflow were identified which could be related to soil type and physiographic position. On gleyed soils derived from rhyolitic colluvium, saturation overland flow was the dominant process. Hydrographs from ‘Whipkey’ throughflow troughs also indicated that there was a subsurface response (saturated wedge) from this soil type. On steeper convex slopes, more permeable soils were derived from weathered greywacke. The presence of ephemeral springs on the hillslopes and direct observation during storm events indicated that storm runoff was generated as return flow from this soil. It was noted that nitrate concentrations from subsurface sources were 5–10 times higher than surface runoff. This difference in concentration was utilized in a chemical mixing equation which partitioned stormflow sources. This was compared with the stormflow predicted from rain falling on to saturated areas. There was good agreement between the two models for winter-spring events with respect to the volumes of surface runoff predicted, however the saturated areas model underestimated total stormflow. The results of the study are briefly discussed in terms of the potential for water quality management.     

Vertical distribution of trace elements in the surface waters offshore Nova Scotia

Concentrations of the trace elements Fe, Al, Mn, Cu, Cd, Zn and Ni were measured in shallow vertical profiles (maximum depth 500 m) off the Scotian Shelf in the western North Atlantic. The distributions of the trace elements show variations with depth, the most consistent of which are for Fe and Zn. A minimum concentration near the surface followed by an increase with depth is attributed to in situ mechanisms.     

Features of clay minerals in the YSDP102 core on the continental shelf of the southeast Yellow Sea

Ninety-eight clay mineral samples from the YSDP102 core were analyzed by x-ray diffractometer to study the four clay minerals: illite, chlorite, kaolinite and smectite. Twenty-eight samples had been analyzed on the laser particle-siz eanalyzer to reveal the particle features of the sediments. Distribution of the clay minerals and the particle characteristics in the YSDP102 core show that the core experienced three different depositional periods and formed three different sedimentary intervals due to different sediment sources and different depositional environments. Features of the clay minerals and the heavy minerals in the YSDP102 core indicate that coarse-grained sediments and fine-grained sediments result from different sources. The Yellow Sea Warm Current has greatly influenced the sedimentary framework of this region since the current‘s formation.     

中国黄土高原塬区表层土壤水分盈缺状况的研究

陆地表层水分的盈缺直接关系到局地气候变化.本文利用黄土高原塬区初夏至盛夏期两次陆面过程野外试验(LOess Plateau land surface process field EXperiment 2005,LOPEX05和LOPEX06)的野外试验观测资料,分析了试验期间黄土高原白庙塬区不同下垫面的水分蒸散和表层土壤水分盈缺状况.结果表明:在土壤水分比较充足的条件下,植被蒸腾增加量在正午时的峰值为0.05 mm·h-1,而较大降水发生后的首个晴日.冬小麦地和裸地的蒸散分别可达4.60 mm·d-和3.70 mm·d-1.局地降水是影响陆面蒸散量变化的主要因素,而植被冠层的存在增加了陆面蒸散发量中的植物蒸腾量值.2006年4月下旬到7月中旬,裸地的水分缺失为16.3 mm·m2,冬小麦地的水分缺失为39.9mm·m2.其中缺失最严重的时间段为5月下旬到6月上旬,最大旬缺失量达16.5 mm·m2,7月上旬和中旬,由于降水季节来临,土壤水分有少量盈余.在2005年7月中旬至8月下旬,玉米地和裸地的水分盈余分别为17.9 mm·m2和25.3 mm·m2.不同时间尺度的统计均表明,降水不仅是影响陆面蒸散量的主要因素,而且也是表层土壤水分盈缺的决定性因子.     

Identification of a new outflow channel on Mars in Syrtis Major Planum using HRSC/MEx data

Syrtis Major Planum is a volcanic plain dominated by lava flows. High resolution stereo camera (HRSC) images of the northern Syrtis Major region display erosional features such as grooves, teardrop-shaped islands and valleys. These landforms are characteristics of outflow channels seen on Mars, therefore implying that a flood event took place in this region. The flow of 100 km long and a few kilometer wide followed the local slopes in most locations. Maximum flood discharges estimated from images and topography vary from about 0.3×10⁶ to 8×10⁶ m³/s, and therefore are in the range of terrestrial mega-floods in the Scablands or Lake Bonneville. In North Syrtis Major, the relationships with surrounding lava flows and the timing of the flood coeval to Syrtis Major volcanic activity suggest that it could be related to the subsurface water discharge mobilized by the volcanic activity. The proximity of Noachian age basement rocks 20 km away from the flood and below lava flows might have played a role in its formation and water presence.