有色噪声作用下的卡尔曼滤波

利用GPS载波相位三差观测量进行动态定位(或精密导航),就必须研究有色噪声滤波的理论问题.根据需求,推导了动态噪声、观测噪声为有色噪声的线性系统滤波公式,并证明白噪声卡尔曼滤波是有色噪声卡尔曼滤波的特例,或者说有色噪声的卡尔曼滤波是白噪声卡尔曼滤波的推广.     

Characteristics and variations of the picophytoplankton community in the Arctic Ocean

Picophytoplankton are responsible for much of the carbon fixation process in the Arctic Ocean, and they play an im- portant role in active microbial food webs. The climate of the Arctic Ocean has changed in recent years, and picophytoplankton, as the most vulnerable part of the high-latitude pelagic ecosystem, have been the focus of an increasing number of scientific studies. This paper reviews and summarizes research on the characteristics of picophytoplankton in the Arctic Ocean, including their abundance, biomass, spatial distribution, seasonal variation, commtmity structure, and factors influencing their growth. The impact of climate change on the Arctic Ocean picophytoplankton community is discussed, and future research directions are considered.     

三维数值模式用于海底摩擦系数的研究

本文讨论了在风暴潮和潮汐作用下海底摩擦力与平均流速的关系公式,即;利用湍流能量损耗理论得到了一个新的求拖曳系数C_b的公式;并且通过一个三维模式,在理想的矩形海区中计算了各种条件下的C_b分布。     

藏东吉塘地区早古生代花岗岩锆石U-Pb年龄、Hf同位素及其对原特提斯洋演化的启示

以前对藏东吉塘地区的早古生代岩浆事件鲜有报道,在吉塘地区的浪拉山新发现了中—晚奥陶世花岗岩。采用LA-ICP-MS锆石U-Pb测年,获得该花岗岩的206Pb/238U年龄加权平均值为455±2.0 Ma（WSWD=1.15,n=26）,属于中—晚奥陶世。岩石地球化学特征表明,该花岗岩具有高SiO2（78.72%~79.48%）、富钾（K2O/Na2O=5.55~10.20）,低MgO（0.10%~0.25%）的特征,铝饱和指数A/CNK为1.08~1.26,岩石属于高钾钙碱性强过铝S型花岗岩。岩石稀土元素总体表现为轻稀土元素富集、重稀土元素亏损的特征,具强烈负Eu异常,δEu值为0.35~0.39;在原始地幔标准化微量元素蛛网图上,明显富集Rb、Th、Nd、Pb等元素,亏损Ba、Nb、Sr、P、Ti等元素。结合区域地质资料分析,该岩体是由原特提斯洋俯冲消减引起古老地壳物质部分熔融形成的,是原特提斯洋俯冲消减的岩浆事件响应;说明在中—晚奥陶世吉塘地区存在原特提斯洋的俯冲消减作用。     

海洋钙离子非保守行为及海洋钙问题

钙离子是海洋11种常量离子之一,与钠、钾等离子的保守性不同,钙离子在海洋中的分布表现出微小但系统的变化。钙离子的变化往往与海洋碳酸钙的形成和溶解过程有关,所以,钙离子可直接指示海洋碳酸钙通量（深层海洋碳通量的主要组成部分）。同时,碳酸钙沉淀或溶解又会改变总碱度和溶解无机碳,通过钙离子变化也能间接探讨海洋碳酸盐系统和海洋吸收CO2的能力。介绍了以碳酸钙溶解形成超额钙为主的海洋钙离子多种非保守行为及其控制过程,讨论这些过程对海水组成和海洋碳酸盐系统的影响,探讨未来海洋酸化条件下钙离子可能的变化及其潜在的效应,最后展望在南海开展钙离子精细行为的研究意义。      

Experiments on the ocean sequestration of fossil fuel CO2: pH measurements and hydrate formation

We have carried out a series of in situ experiments to investigate the formation of a CO₂ hydrate (CO₂:5.75 H₂O) for the purpose of evaluating scenarios for ocean fossil fuel CO₂ disposal with a solid hydrate as the sequestered form. The experiments were carried out with a remotely operated vehicle in Monterey Bay at a depth of 619 m. pH measurements made in close proximity to the hydrate–seawater interface showed a wide range of values, depending upon the method of injection and the surface area of the hydrate formed. Rapid injection of liquid CO₂ into an inverted beaker to form a flocculant mass of hydrate resulted in pH initially as low as 4.5 within a few centimeters of the interface, decaying slowly over 1–2 h towards normal seawater values as dense CO₂ rich brine drained from the hydrate mass. In a second experiment, slower injection of the liquid CO₂ to produce a simple two-layer system with a near planar interface of liquid CO₂ with a thin hydrate film yielded pH values indistinguishable from the in situ ocean background level of 7.6. Both field and laboratory results now show that the dissolution rate of a mass of CO₂ hydrate in seawater is slow but finite.     

NUMERICAL EXPERIMENTS OF EFFECT OF SSTA OVER THE INDIAN OCEAN ON ATMOSPHERIC LOW-FREQUENCY OSCILLATION IN THE EXTRATROPICAL LATITUDE

Numerical experiments on forcing dissipation and heating response of dipole (unipole) are carried out using global spectral models with quasi-geostrophic barotropic vorticity equations. For each experiment model integration is run for 90 days on the condition of three-wave quasi-resonance. The results are given as follows: Under the effects of dipole (unipole) forcing source and basic flow intensity, there exist strong interactions among the three planetary waves and quasi-biweekly and intraseasonal oscillation of the three planetary waves. In the meantime, the changes in the intensity of dipole or unipole forcing source and basic flow have different frequency modulation effects on LFO in the middle and higher latitudes. The results of the stream function field of three quasi-resonant waves evolving with time confirm that the low-frequency oscillation exists in extratropical latitude.     

Coming to the table: Early stakeholder engagement in marine spatial planning

From 2009 to 2011, marine spatial planning (MSP) rapidly gained visibility in the United States as a promising ocean management tool. A few small-scale planning efforts were completed in state waters, and the Obama Administration proposed a framework for large-scale regional MSP throughout the U.S. Exclusive Economic Zone. During that same time period, the authors engaged a variety of U.S ocean stakeholders in a series of dialogs with several goals: to share information about what MSP is or could be, to hear stakeholder views and concerns about MSP, and to foster better understanding between those who depend on ocean resources for their livelihood and ocean conservation advocates. The stakeholder meetings were supplemented with several rounds of in-depth interviews and a survey. Despite some predictable areas of conflict, project participants agreed on a number of issues related to stakeholder engagement in MSP: all felt strongly that government planners need to engage outsiders earlier, more often, more meaningfully, and through an open and transparent process. Equally important, the project affirmed the value of bringing unlike parties together at the earliest opportunity to learn, talk, and listen to others with whom they rarely engage.     

GNSS接收机晶振参数对载波相位测量的影响分析

分析了射频与基带时钟不同源对载波相位测量的影响,构建了由晶振各类误差源引起的载波环跟踪误差模型。分析与实验结果表明,时钟不同源会导致载波相位测量出错,晶振引起的载波环测量误差随环路噪声带宽增大而减小,减小晶振的h系数和g灵敏度可提高测量精度。选用单一稳定度高、g灵敏度小的晶振作为GNSS接收机时钟,可改善载波相位精度。