A new lunar absolute control point: established by images from the landing camera on Chang'e-3

The establishment of a lunar control network is one of the core tasks in selenodesy, in which defining an absolute control point on the Moon is the most important step. However, up to now, the number of absolute control points has been very sparse. These absolute control points have mainly been lunar laser ranging retroreflectors, whose geographical location can be observed by observations on Earth and also identified in high resolution lunar satellite images. The Chang'e-3(CE-3) probe successfully landed on the Moon, and its geographical location has been monitored by an observing station on Earth. Since its positional accuracy is expected to reach the meter level, the CE-3 landing site can become a new high precision absolute control point. We use a sequence of images taken from the landing camera, as well as satellite images taken by CE-1 and CE-2, to identify the location of the CE-3 lander. With its geographical location known, the CE-3 landing site can be established as a new absolute control point, which will effectively expand the current area of the lunar absolute control network by 22%, and can greatly facilitate future research in the field of lunar surveying and mapping, as well as selenodesy.     

Data processing and initial results from the CE-3 Extreme Ultraviolet Camera

The Extreme Ultraviolet Camera(EUVC) onboard the Chang'e-3(CE-3)lander is used to observe the structure and dynamics of Earth's plasmasphere from the Moon. By detecting the resonance line emission of helium ions(He+) at 30.4 nm, the EUVC images the entire plasmasphere with a time resolution of 10 min and a spatial resolution of about 0.1 Earth radius(RE) in a single frame. We first present details about the data processing from EUVC and the data acquisition in the commissioning phase, and then report some initial results, which reflect the basic features of the plasmasphere well. The photon count and emission intensity of EUVC are consistent with previous observations and models, which indicate that the EUVC works normally and can provide high quality data for future studies.     

Baryon loading and the Weibel instability in gamma-ray bursts

The dynamics of two counter-streaming electron–positron–ion unmagnetized plasma shells with zero net charge is analysed in the context of magnetic field generation in gamma-ray burst internal shocks due to the Weibel instability. The effects of large thermal motion of plasma particles, arbitrary mixture of plasma species and space charge effects are taken into account. We show that, although thermal effects slow down the instability, baryon loading leads to a non-negligible growth rate even for large temperatures and different shell velocities, thus guaranteeing the robustness and the occurrence of the Weibel instability for a wide range of scenarios.     

珠江黄茅海河口洪季侧向余环流与泥沙输移

2012年洪季对珠江黄茅海河口湾侧向动力结构与泥沙输移过程进行了系统观测,采用动量平衡和泥沙通量机制分解等方法,分析了河口流、温盐和泥沙侧向分布特征以及泥沙输移过程,探讨了侧向动量平衡与泥沙输移机制。洪季黄茅海河口存在明显的侧向流,西滩和北槽均形成表层向东、底层向西的两层侧向流,拦门沙滩顶呈现表、底层向西、中层向东的三层侧向流,而拦门沙前缘侧向流整体向西。河口湾纵向净泥沙通量表现为北槽向海、西滩向陆,拦门沙滩顶及其前缘均向海;侧向净泥沙通量表现为滩顶及其前缘均向西,西滩向东、北槽向西。这种侧向泥沙辐聚过程是高浓度悬沙聚集于滩槽界面的重要原因,向陆净通量是西滩回淤的重要原因。滩槽间侧向余环流动量平衡主要是侧向斜压梯度力、科氏力和侧向平流作用。欧拉平流输运在侧向泥沙输运中起主要作用,潮泵效应也起重要作用。     

我国海洋学科研究生培养专业开设现状分析与展望

21世纪是海洋的世纪,海洋强国战略的实施需要海洋科学人才支撑。通过对我国已有的涉及海洋科学学科研究生培养的高校和研究所的全面调研和分析比较,总结我国海洋科学研究生学科专业开设院所、依托平台、专业开设的现状、取得的成果,指出目前我国海洋科学方向研究生教育学科专业开设与建设海洋强国战略人才需求之间的矛盾和存在的不足,提出相应的建议和展望,旨在为我国海洋科学学科的研究生教育和人才培养提供有益的借鉴和参考。     

基于Argo资料的世界大洋温度跃层的分布特征

基于2002年至2007年Argo浮标温度剖面资料,计算温度跃层特征参数,判定跃层的类型。在此基础之上,绘制了世界大洋四季温度跃层特征分布图。分析结果初步揭示了世界大洋温度跃层深度和强度的分布规律及其冬、夏两季的变化规律。     

基于Argo网格产品资料的台湾以东海域海温场结构与温跃层特征分析

基于2005年1月~2009年12月中国Argo实时数据中心发布的Argo网格化产品,对台湾以东海域的表层和深层海温进行了分析,证实了日本南部海域存在北太平洋副热带模态水,提出暖水团概念,分析了其成因和垂直结构,并利用SODA(Simple Ocean Data Assimilation)数据和WOA09(World Ocean Atlas 2005)数据对暖水团进行验证。揭示出台湾以东海域各层次温度大面分布大体呈3个模态特征,并依此将台湾以东海域分为热带、副热带和温带三个海区;对各海域截取断面图,对其温跃层进行分析,归纳出永久性温跃层和季节性温跃层在垂直方向上的分布和季节性变化,并对其成因进行了讨论。     

北黄海盆地东部M隆起构造特征及演化

北黄海盆地是中国东部近海中生代断陷型盆地,详细记载着中国东部复杂的构造活动信息,期间经历了多期岩浆活动和构造反转。M隆起位于北黄海盆地东部,其构造活动记录比周边的坳陷更为详细。为充分认识M隆起的地质结构及沉积响应关系,在充分利用地震、钻测井等资料的基础上,结合区域构造背景,从构造运动学和动力学等方面探讨分析其构造演化历程,进而为北黄海盆地乃至中国东部地区的构造演化提供新的依据。高精度三维地震资料及地质分析揭示,该隆起区发育有5个典型的不整合面,纵向上可划分为5个构造层。结合北黄海盆地所处构造位置、构造变形和沉积充填特征,及板块运动和区域构造演化史,将北黄海盆地东部M隆起自中侏罗世至今的构造演化划分为5个阶段(共9期):裂陷阶段(稳定沉积期、掀斜形成期、早白垩世凹陷沉积期)、构造反转阶段(晚白垩世抬升剥蚀期)、再次裂陷阶段(早渐新世初沉积期、早渐新世末剥蚀期、F2断层活跃期)、再次构造反转阶段(整体抬升期)、区域沉降阶段(区域沉降期)。     

清洁疏浚物对2种海洋微藻种间竞争的影响

采用实验生态学方法,研究了不同起始密度下悬浮清洁疏浚物对中肋骨条藻Skeletonema costatum和赤潮异弯藻Heterosigma akashiwo生长的影响。研究结果表明,在实验室单培养条件下,清洁疏浚物培养液中,起始密度不同,微藻生长状况明显不同。起始密度为0.2×10⁴ cells·mL^-1时,进入指数生长期和静止期的时间延长,但生长所达到的最大细胞密度较高;起始密度为0.8×10⁴ cells·mL^-1时,进入指数生长期和静止期的时间缩短,但生长所达到的种群最大密度较低。混合培养条件下,清洁疏浚物培养液中,起始密度不同,导致了微藻种间竞争关系的变化,中肋骨条藻与赤潮异弯藻具有明显的种间竞争,赤潮异弯藻是竞争的优胜者,中肋骨条藻受到赤潮异弯藻的抑制,整个实验周期内细胞密度下降都非常明显,细胞密度明显低于单培养时的细胞密度,而赤潮异弯藻细胞密度并没有明显的减少。在3种不同质量浓度组清洁疏浚物培养液中,质量浓度最高的1 000 mg·L^-1培养液中藻细胞密度显著低于100 和500 mg·L^-1质量浓度组,而100 mg·L^-1培养液中藻细胞密度最高,说明清洁疏浚物质量浓度越高,对海洋微藻抑制影响越为明显,质量浓度越低,影响越小。