Squat effects on high speed craft in restricted waterways

The vessels considered here for the squat studies are a bulk carrier and an High Speed Craft (HSC). The bulk carrier of full form (C_B=0.81) is used for validation purpose and subsequently the numerical computations are performed for a High Speed Craft with fine hull form of C_B=0.467. A high speed ferry, with LCB and LCF quite aft of midship is considered for squat study. For a vessel speed of above 6.0 knots and for a waterway width greater than the vessel length there appears to be a sudden increase in sinkage at the stern accompanied by a large value of bow emergence. It could be seen that the speed of the vessel has a much greater influence on the sinkage and trim of the vessel than the waterway restrictions.     

Policies governing the distribution of by-products from scientific and small-scale coastal whaling in Japan

The Japanese government is committed to resuming sustainable commercial whaling, both on the high seas and along the Japanese coastline. To this end scientific whaling programs are supported with public money and the byproducts of the catch are distributed to the public and utilized in a variety of ways. Here we review the policies which govern how these byproducts are disseminated within Japan, as well as how the population as a whole makes use of whale resources. Possibilities for the future, if and when the international moratorium on commercial whaling ends, are also discussed.     

Multiple criteria optimization applied to high speed catamaran preliminary design

The demand for high-speed craft (mainly catamarans) used as passenger vessel has increased significantly in the recent years. Looking towards the future and trying to respond to the increasing requirement, high-speed crafts international market is passing through deep changes. Different types of high-speed crafts are being used for passenger transport. However, catamarans and monohulls have been the main choice not only for passenger vessel but also as ferryboat.Generally speaking, the efficient hydrodynamic hull shapes, engine improvements, and lighter hull structures using aluminum and composite materials make possible the increase in cruising speed.The high demand for catamarans are due to its proven performance in calm waters, large deck area compared to monohull crafts and higher speed efficiency using less power. Although the advantages aforementioned, the performance of catamaran vessels in wave conditions still needs to be improved.The high-speed crafts (HSC) market is demanding different HSC designs and a wide range of dimensions focusing on lower resistance and power for higher speed. Therefore, the hull resistance optimization is a key element for a high-speed hull success.In addition to that, trade-off high-speed catamaran (HSCat) design has been improved to achieve main characteristics and hull geometry. This paper presents a contribution to HSCat preliminary design phase. The HSCat preliminary design problem is raised and one solution is attained by multiple criteria optimization technique.The mathematical model was developed considering: hull arrangement (area and volume), lightweight material application (aluminum hull), hull resistance evaluation (using a slender body theory), as well as wave interference effect between hulls, calculated with 3D theory application. Goal programming optimization system was applied to solve the HSCat preliminary design.Finally this paper includes an illustrative example showing the mathematical model and the optimization solution. An HSCat passenger inland transport in Amazon area preliminary design was used as case study. The problem is presented, the main constrains analyzed and the optimum solution shown. Trade off graphs was also included to highlight the mathematical model convergence process.     

Nitrate in groundwater of China: Sources and driving forces

Identifying the sources of reactive nitrogen (N) and quantifying their contributions to groundwater nitrate concentrations are critical to understanding the dynamics of groundwater nitrate contamination. Here we assessed groundwater nitrate contamination in China using literature analysis and N balance calculation in coupled human and natural systems. The source appointment via N balance was well validated by field data via literature analysis. Nitrate was detected in 96% of groundwater samples based on a common detection threshold of 0.2 mg N L^?1, and 28% of groundwater samples exceeded WHO's maximum contaminant level (10 mg N L^?1). Groundwater nitrate concentrations were the highest beneath industrial land (median: 34.6 mg N L^?1), followed by urban land (10.2 mg N L^?1), cropland (4.8 mg N L^?1), and rural human settlement (4.0 mg N L^?1), with the lowest found beneath natural land (0.8 mg N L^?1). During the period 1980–2008, total reactive N leakage to groundwater increased about 1.5 times, from 2.0 to 5.0 Tg N year^?1, in China. Despite that the contribution of cropland to the total amount of reactive N leakage to groundwater was reduced from 50 to 40% during the past three decades, cropland still was the single largest source, while the contribution from landfill rapidly increased from 10 to 34%. High reactive N leakage mainly occurred in relatively developed agricultural or urbanized regions with a large population. The amount of reactive N leakage to groundwater was mainly driven by anthropogenic factors (population, gross domestic product, urbanization rate and land use type). We constructed a high resolution map of reactive N source appointment and this could be the basis for future modeling of groundwater nitrate dynamics and for policy development on mitigation of groundwater contamination.     

Snowmelt variability in Polar Bear Pass,Nunavut, Canada,from QuikSCAT: 2000–2009

Snowmelt onset and end date estimates are made from QuikSCAT scatterometer measurements in the Canadian High Arctic wetland of Polar Bear Pass (PBP) and the surrounding region of Bathurst Island, Nunavut. In situ data within PBP is used to validate QuikSCAT snowmelt onset/end date estimates. Results indicate that within PBP from 2000 to 2009, the mean snowmelt onset date was Year Day (YD) 162, the mean snowmelt end date was YD179, and the mean snowmelt duration was 17 days. More interannual variability was apparent in snowmelt end date and duration compared with onset, and only snowmelt end date was significantly correlated with mean June air temperature at ?0.78. Cooler air temperatures in 2004 contributed to a long snowmelt duration of 24 days, and the very short snowmelt duration in 2007 of just 11 days was caused by rapid and sustained increases in air temperature. For snowmelt end date and duration the mean spatial pattern revealed two centres of later snowmelt end date/longer snowmelt duration over Bathurst Island. They were separated by early snowmelt end date/short snowmelt duration in PBP. These patterns are in agreement with the spatial distribution of mean May to July air temperature over Bathurst Island and are likely influenced by the local‐scale topography of Bathurst Island. Given the correlation between air temperature and snowmelt end date, we might expect quicker snowmelt under increased warming. The latter process may have implications for the sustainability of the PBP wetland under a warmer climate. Copyright © 2011 John Wiley & Sons, Ltd.     

商代含高放射性成因铅的青铜器矿料来源与古蜀三星堆在矿业贸易中的地位

含高放射性成因铅是商代青铜器的重要特征,但对其矿料来源的讨论众说纷纭,莫衷一是。本文收集了河南郑州商城、山西垣曲商城、湖北盘龙城、四川三星堆、陕西汉中（地区）、江西新干大洋洲、河南安阳殷墟和陕北（地区）覆盖整个商代的8个遗址/地区700件出土青铜器样品的铅同位素组成数据,并与全国606个Pb—Zn、Cu、Sn多金属矿床4025件矿石样品的铅同位素组成数据进行比对分析,探讨商代青铜器的矿料来源和古蜀国在矿业贸易中的地位。研究表明：（1）河南郑州商城、湖北盘龙城、陕西汉中、山西垣曲商城、河南安阳殷墟和陕北6个遗址/地区的青铜器很可能采用了含异常铅和正常铅的两类铅料;而四川三星堆与江西新干大洋洲出土的青铜器则主要采用了含异常铅的铅料。四川三星堆、陕西汉中和陕北3个遗址/地区出土的青铜器很可能采用了含异常铅和正常铅的两类铜料;而河南郑州商城、湖北盘龙城、山西垣曲商城、河南安阳殷墟与江西新干大洋洲出土的青铜器采用的铜料很可能以含正常铅为主,但不排除采用含异常铅铜料的可能性。（2）对比全国Cu、Pb—Zn、Sn及多金属矿床铅同位素资料,商代遗址出土的青铜器中的高放射性成因铅的铅料,最有可能来自四川云南交界处的MVT型Pb—Zn矿床;而含高放射性成因铅的铜料,则最可能来自四川云南交界处的IOCG型Cu矿和山西中条山铜矿峪Cu矿床。（3）综合三星堆遗址得天独厚的地理位置,三星堆青铜文明的兴衰时间及其与其他文化交流与贸易往来的路径,推测古蜀三星堆很可能是商代含高放射性成因铅的铅料及部分铜料贸易的大型中转地,商代含高放射性成因铅的青铜器的兴盛与衰落则很可能与三星堆青铜文明的开启与消亡有关。     

Late Jurassic intraplate extension in southern Central Asian Orogenic Belt: Evidence from Beidashan mafic rocks in AlxaSCIEI北大核心CSCD

阿拉善地块北缘晚中生代(晚侏罗世-早白垩世)时期发育有广阔的伸展盆地体系,其形成可能与陆内伸展作用有关。本文首次在阿拉善地块西北缘北大山陶来地区识别出一套晚侏罗世镁铁质-超镁铁质岩,对其进行系统的岩石学、年代学和地球化学研究,从而为该地区陆内伸展提供岩浆作用方面的证据。LA-ICP-MS锆石U-Pb定年结果表明,北大山陶来地区角闪辉长岩形成时代为155.7±4.6Ma(MSWD=1.5),即晚侏罗世。角闪辉长岩显示出高铝基性岩的地化特征,如低SiO 2(48.0%~52.5%),高Al 2O 3(15.3%~18.2%)、MgO(8.78%~10.6%)和CaO(12.8%~16.7%)。此外,它们还显示出高的Mg#(72~82)、Cr(295×10^(-6)~960×10^(-6))和Ni(97.4×10^(-6)~186×10^(-6)),N-MORB型和平坦的HREE配分形式、Eu正异常,较高的Nb/La比值,这些都表明其可能为软流圈地幔减压熔融产生的原始岩浆与壳幔过渡带中含斜长石堆晶岩相互作用后分离结晶的产物。富铝和富钙源区以及岩浆中高的水含量抑制斜长石早期成核与生长共同控制了高铝角闪辉长岩的形成。辉长岩表现出N-MORB型全岩地球化学特征和板内成因岩浆锆石特征(高Nb/Hf及低Hf/Th、Th/Nb),均揭示了阿拉善西北缘陶来地区晚侏罗世镁铁质-超镁铁质岩体是板内岩石圈伸展作用的产物。在古亚洲洋最终碰撞闭合后伸展基础上,蒙古-鄂霍茨克洋闭合与古太平洋俯冲后撤叠加作用引发了岩石圈伸展,并沿中亚造山带南缘多个古生代缝合带产出了194~124Ma多期镁铁质-超镁铁质岩。     

Simulation of location-specific severe thunderstorm events using high resolution land data assimilation

In this study, the impact of different land initial conditions on the simulation of thunderstorms and monsoon depressions is investigated using the Weather Research and Forecasting (WRF) model. A control run (CNTL) and a simulation with an improved land state (soil moisture and temperature) using the High Resolution Land Data Assimilation System (HRLDAS, experiment name: EHRLDAS) are compared for three different rainfall cases in order to examine the robustness of the assimilation system. The study comprises two thunderstorm cases (one in the pre-monsoon and one during the monsoon) and one monsoon depression case that occurred during the Interaction of Convective Organisation, Atmosphere, Surface and Sea (INCOMPASS) field campaign of the 2016 Indian monsoon. EHRLDAS is shown to yield improvements in the representation of location-specific rainfall, particularly over land. Further, it is found that surface fluxes as well as convective indices are better captured for the pre-monsoon thunderstorm case in EHRLDAS. By analysing components of the vorticity tendency equation, it is found that the vertical advection term is the major contributor towards the positive vorticity tendency in EHRLDAS compared to CNTL, hence improving localised convection and consequently facilitating rainfall. Significant improvements in the simulation of the pre-monsoon thunderstorm are noted, as seen using Automatic Weather Station (AWS) validation, whereas improvements in the monsoon depression are minimal. Further, it is found that vertical advection (moisture flux convergence) is the major driver modulating the convective circulation in localised thunderstorm (monsoon depression) cases and these dynamics are better represented by EHRLDAS compared to CNTL. These findings underline the importance of accurate and high resolution land-state conditions in model initial conditions for forecasting severe weather systems, particularly the simulation of localised thunderstorms over India.     

高分三号山地冰川表面运动提取与分析

冰川表面运动提取在冰川动力学与物质平衡变化研究中具有重要意义。针对当前我国自主遥感卫星数据在冰川运动监测应用中存在的不足,选用GF-3卫星FSI模式下获取的2019—2020年间覆盖亚洲高山区典型冰川的SAR数据,借助并行化偏移量跟踪算法获取了研究区冰川表面流速分布。研究结果表明：优化后的偏移量跟踪算法极大地提高了运行效率;全局形变拟合估计、地形偏差校正及滤波降噪后,冰川运动分布形态更加直观,精度可达0.5 m;通过与准同期Landsat-8影像提取的冰川流速对比以及对非冰川区位移残差的统计分析,验证了GF-3影像在监测不同区域冰川流速结果方面的可靠性及适用性;GF-3影像凭借其良好的空间分辨率,在规模较小、运动缓慢的冰川运动提取方面具有显著的优势,能够更好地体现冰川运动细节信息及其差异性。该研究有助于分析气候变化背景下青藏高原地区冰川的运动规律及其时空演变特征。