无人船测量技术在矿区堰塞湖水下地形监测中的应用

利用无人船技术开展堰塞湖体等传统方式测量困难水域的水下地形数据的采集与监测,能够安全、快速地获取水下地形、断面图、水体库容等信息.本文以翠宏山铁多金属矿堰塞湖应急测量工作为例,介绍了无人船测量系统的组成,并详细阐述了利用无人船开展水下测量的实施与数据后处理步骤.应用结果表明,利用无人船测量系统能够有效避免测量时的安全威胁,为困难水域的水下地形测量提供可靠的数据支撑.     

复杂水域条件下单波束无人船地形测量应用

水下测量是测绘工作的一个重要组成部分,利用水下测量技术可获取水下地形、河道纵横断面、水深等数据,保障水域施工、水下救援、河道疏浚等工作的正常开展.相较于传统的人工水下测量手段,搭载声呐设备的无人船水下测量系统以其测量速度快、人工成本低、安全系数高、精度高等特点迅速成为水下测量工作所使用的主流技术,并在很多项目中开展应用.在应用过程中发现,无人船测量环境较为复杂,一般的技术流程往往难以满足实际需要.因此,本文从单波束无人船的测量原理出发,结合实际案例,探讨单波束无人船在复杂水域地形测量中存在的问题及解决方式,形成无人船在复杂水域地形测量的技术流程.     

楼兰古城消失之谜引世人关注

延续了数千年的文明,湮没了数千年的记忆,慢慢揭开了神秘面纱,楼兰古城,在风沙和荒烟中渐渐显露出来。考古专家根据楼兰古城附近遗址出土的古墓干尸推论,在距今4000年左右,楼兰地区生活着一群以游牧为生的人。他们金发碧眼,与古欧罗巴人种同宗。或许是因为逐水草而居,他们仅留下几具干尸,就神秘地消失了。其后2000余年,这一地区的历史出现断层,考古发掘和文献中均找不到楼兰的一丝痕迹。从此,楼兰的这段历史成了不解之谜。随着科学考察的不断深入,人们提出了关于楼兰古城灭亡的六种假说。     

用DGPS双天线系统校验定位辅助设备的方法探讨

随着GPS技术的快速发展,使用DGPS定位的精度越来越高,这就为物探船上定位辅助设备的精确校准与校验提供了可能.通过对发现六号物探船定位辅助设备的校准与校验,初步形成了一套比较可行的作业方法.此文结合校验方法及其可行有效性分析,详细阐述了校验方法,并试图对校验误差来源进行探讨,以期提高对定位辅助设备校准与校验的精确度.     

南黄海地震资料邻船干扰特征及压制方法

受过往船只的影响,南黄海地震原始资料普遍存在邻船干扰,使地震数据的品质受到严重影响。在系统总结前人研究成果的基础上,指出邻船干扰在炮集上具有直线型、双曲线型和不规则近双曲线形态,同时具有传播路径相对简单、相对高振幅、宽频带特征。利用将邻船干扰拉平后去除及共偏移距域内f—x预测滤波方法对南黄海二维地震资料进行了测试,结果表明,2种方法均能较好地去除邻船干扰,其中后者更易于实现。     

Variation of freshwater components in the Canada Basin during 1967–2010

As a conservative tracer, oxygen isotopes in seawater are widely used for water mass analysis, along with temperature and salinity. In this study, seawater oxygen-18 datasets in the Canada Basin during 1967–2010 were obtained from the four cruises of the Chinese National Arctic Research Expedition(1999, 2003, 2008, and 2010) and the NASA database. Fractions of sea ice meltwater and river runoff were determined from the salinity-18O system. Our results showed that the river runoff decreased from the south to the north in the Canada Basin. The enhanced amount of river runoff observed in the southern Canada Basin may originate from the Mackenzie River, transported by the Beaufort Gyre. The river runoff component showed maximum fractions during 1967–1969, 1978–1979, 1984–1985, 1993–1994, and 2008–2010, indicating the refresh time of the river runoff was 5.0–16.0 a in the Canada Basin. The temporal variation of the river runoff was related to the change of the Arctic Oscillation(AO) index, suggesting the freshwater stored in the Canada Basin was affected by surface sea ice drift and water mass movement driven by atmospheric circulation.     

Low 210Pb in the upper thermocline in the Canadian Basin: scavenge process over the Chukchi Sea

210Pb was measured during the 3rd Chinese National Arctic Research Expedition cruise to investigate its spatial pattern in the western Arctic Ocean, as well as its relation with the thermocline in the Canadian Basin. The specific activities varied from 0.04 to 2.72, 0.013 to 4.37, and 0.1 to 4.85 Bq/m3 for dissolved, particulate, and bulk 210Pb, respectively, corresponding to respective averages of 0.65, 0.43, and 1.08 Bq/m3. In the Canadian Basin, the minimum 210Pb activities occurred in the thermocline, which was characterized by low temperature of-1.52°C and salinity of 33.1. Combining the spatial distribution of 210Pb and hydrographical characteristics in the western Arctic Ocean, this scenario was ascribed to the effective scavenging of 210Pb when the Pacific water flowed across the Chukchi Shelf. Quantitatively, this interpretation was supported by both the shorter residence times and higher scavenging efficiencies(SE) of dissolved 210Pb over the Chukchi Shelf. The highest SE values were observed in the Herald Shoal and bottom waters over the slope.     

Distribution of dissolved oxygen and causes of maximum concentration in the Bering Sea in July 2010

According to data obtained in the Bering Sea during the 4th Chinese National Arctic Research Expedition, the distribution of dissolved oxygen(DO) was studied, causes of its maximum concentration were discussed, and the relationships between DO and other parameters, such as salinity, temperature, and chlorophyll a were analyzed. The results showed DO concentration ranged from 0.53 to 12.05 mg/L in the Bering Sea basin. The upper waters contained high concentrations and the maximum occurred at the depth range from 20 to 50 m. The DO concentration decreased rapidly when the depth was deeper than 200 m and reached the minimum at the depth range from 500 to 1 000 m, and then increased slowly with the depth increasing but still kept at a low level. On the shelf, the DO concentration ranged from 6.53 to 16.63 mg/L with a mean value of 10.75 mg/L, and showed a characteristic of decreasing from north to south. The DO concentration was higher in the area between the Bering Sea and Lawrence Island and was lower in the southeast and southwest of Lawrence Island at the latitude of 62°N. The formation of maximum DO concentration was concerned with phytoplankton photosynthesis and formation of the themocline. To the south of Sta. B07 in the Bering Sea basin, the oxygen produced by photosynthesis permeated to the deeper water and the themocline made it difficult to exchange vertically, and to the north of Sta. B07, the maximum DO concentration occurred above the themocline due to phytoplankton activities. On the shelf, the oxygen produced by phytoplankton photosynthesis gathered at the bottom of the thermocline and formed the DO maximum concentration. In the Bering Sea basin, the DO and salinity showed a weak negative correlation(r=0.40) when the salinity was lower than 33.1, a significant negative correlation(r=0.92) when the salinity ranged from 33.1 to 33.7, and an irregular reversed parabola(r=0.95) when the salinity was greater than 33.7.     

Abundance and distribution of meiofauna in the Chukchi Sea

The metazoan meiofauna in the Chukchi Sea were collected from seven shallow water stations(depths ranging 46 to 52 m) and five deep sea stations(depths ranging between 393 and 2 300 m) during the 4th Chinese National Arctic Research Expedition in 2010. The results showed that abundance of meiofauna was higher in shallow water sediments(average of 2 445 ind./(10 cm2)) than in deep sea sediments(407.06 ind./(10 cm2)). A UNIANOVA test for difference between the two different regions was highly significant(F=101.15, p0.01). Nematodes were numerically dominant, representing(96.6±4.6)% of the total meiofaunal abundance at the shallow water stations and(98.90±1.42)% at deep sea stations. The number of higher taxonomic groups and abundance of meiofauna were higher at Stas CC1, CC4, and R06 near the Bering Strait and the continent, than at the rest of the shallow water and deep sea stations. The primary factors causing the differences were concentrations of nutrients P and Si of bottom seawater(R=0.831, p0.003), followed by depth(R=-0.655, p0.05) and sand fractions of sediments(R=0.632, p 0.05). The numbers of meiofauna on the 65 μm and 32 μm sieves were significantly higher than those on the rest of the screens. Differences in numbers of meiofauna retained on screens with different mesh openings were highly significant among all sampling stations(F=31.60, p0.01). The highest numbers of individuals on screens with 32 μm mesh openings were found at deep sea stations. The number of meiofauna in the top 0–1, 1–2, and 2–4 cm segments constituted 84.4% of the total and was significantly higher than those in the bottom 4–6 and 6–10 cm segments(F=15, p0.01).     

“地球”号钻探船即将探测日本地震带——震后快速考察将测量断层余热

在经历了2011年3月11日日本东北部毁灭性地震所引发的海啸的强烈颠簸和重创之后,日本“地球”号（Chikyu）钻探船被赋予了一项非常适合自己的新的使命：在靠近引发海啸的9．0级东日本地震震中的断裂带开展钻探业务并进行温度测量。