海洋观测中的实时操作系统分析研究

海洋观测是获取海洋环境信息的重要方式,实时、可靠的操作系统是海洋观测中信息采集与处理系统的重要组成部分。实时操作系统计算的正确性不仅取决于计算的逻辑正确性,还取决于产生结果的时间。该系统具有高精度计时系统、多级中断嵌套机制和实时调度机制,这些特性保证任务在规定的时间内完成。文中对三个典型的操作系统(Wind River公司的Vx Works、BRTT公司的Antelope和开源的RTLinux)进行研究,并从功能、关键模块以及优缺点等方面进行分析论证,详细阐述了实时操作系统的功能特性以及实时操作系统在相关领域应用的重要性。     

海洋科技在21世纪海上丝绸之路建设中的作用

21世纪海上丝绸之路建设在海洋经济活动、海上综合保障等方面对海洋科技领域提出了新命题。在分析我国海洋技术优势领域的基础上,围绕科技创新政策伙伴关系、培育创新品牌、推进海洋经济和产业发展等方面,深入阐述了海洋科技领域在21世纪海上丝绸之路建设中的支撑作用,同时提出具体工作思路。     

碳纳米管和纳米二氧化钛复合光催化剂处理海洋柴油污染的研究

利用溶胶凝胶法自制了碳纳米管和纳米二氧化钛的复合光催化剂,采用投射电子显微镜和X光衍射仪对粉体的粒径、物象、形貌和热稳定性等进行表征。通过研究光照条件、催化剂的投加量、油的初始浓度、催化剂制备的煅烧条件等因素,考察了自制碳纳米管和纳米二氧化钛的复合催化剂对降解模拟海洋柴油污染的海水去除率的影响。研究发现,在可见光照条件下,400℃煅烧2 h的复合催化剂,投加量为0.4 g/L、柴油的初始浓度为0.6 g/L、反应的光照时间为4 h时效果最好,去除率可达到67.65%。     

正弦激励下零浮力海洋拖缆动力特性与实验研究

海洋地震拖缆是海洋油气资源勘探中的关键设备,为研究海洋地震拖缆的动力特性及其在不同频率正弦激励干扰下的动力响应,建立了零浮力拖缆的数学模型,设计了一套完整的实验方案,通过弹性测力机构放大张力信号以排除环境干扰,测量了不同拖曳速度与激振频率条件下拖缆首部的张力变化及缆上位移响应情况,初步分析了正弦激励作用下零浮力拖缆的动力学响应。弹性测力机构具有良好的线性度与可重复性,拖缆受到的水阻力与拖曳速度的平方成正比,数值计算与实验结果对比验证了数学模型的正确性,初步分析了正弦激励作用下零浮力拖缆的动力学响应。     

水平轴潮流能叶轮尖速比特性分析研究

针对设计尖速比对水平轴潮流能叶轮动力特性的影响问题开展研究工作。基于叶素-动量理论建立叶轮动力特性仿真模型,以叶片数量分别为2、3、4的叶轮为对象,考察设计尖速比对叶轮的功率系数的影响。研究结果表明:设计尖速比越大的叶轮,其最大效率也越高;叶片数量多的叶轮,其功率系数略优于叶片数量少的叶片。结合分析结果,给出了水平轴潮流能叶轮的设计尖速比的选择建议。     

海洋重力测量动态环境效应分析与补偿

针对使用小型测量船搭载摆杆型海洋重力仪获取数据质量不高的问题,在深入分析海洋环境动态效应误差特性基础上,提出了一种基于互相关分析的交叉耦合效应修正法,对高动态海洋重力测量数据实施综合误差补偿和精细处理。使用典型恶劣海况条件下的观测数据对该方法的有效性进行了验证,结果显示,重力测线成果内符合精度从原先的±9.35×10-5m/s2大幅提升到±1.43×10-5m/s2,同时使用卫星测高反演重力对精细处理结果的可靠性进行了外部检核,外符合精度也从原先的±7.73×10-5m/s2提高到±5.63×10-5m/s2。     

伴随对流层中低层气温持续下降的雪转雨过程分析

利用欧洲中期天气预报中心（ECMWF）0.25°×0.25°分辨率细网格模式产品、探空观测资料和风廓线雷达等资料,对2014年2月18日浙江嘉兴雨雪天气过程中降水相态先由雨转雪、再由雪转雨的变化条件进行了分析,并对ECMWF细网格模式产品进行了预报性能检验,结果表明：模式形势预报准确,但未能预报出雪转雨过程。在对流层中低层气温持续降低的情况下,水汽凝结高度不同是造成两次相态转换的主要原因。上午垂直运动加强,水汽充沛,降水粒子的凝结高度高,足以形成大的雪花,在较低的零度层高度以下降落时不至于融化;下午垂直运动减弱,水汽集中在低层,尽管这一高度层的气温在-3～-2 ℃,但是不足以凝结成固态降水,同时地面气温受海上暖平流影响而回升,因此降水相态由雪转雨。     

Deep convective clouds over the northern Pacific and their relationship with oceanic cyclones

Based on combined Cloud Sat/CALIPSO detections, the seasonal occurrence of deep convective clouds(DCCs) over the midlatitude North Pacific(NP) and cyclonic activity in winter were compared. In winter, DCCs are more frequent over the central NP, from approximately 30°N to 45°N, than over other regions. The high frequencies are roughly equal to those occurring in this region in summer. Most of these DCCs have cloud tops above a 12 km altitude, and the highest top is approximately 15 km. These wintertime marine DCCs commonly occur during surface circulation conditions of low pressure, high temperature, strong meridional wind, and high relative humidity. Further, the maximum probability of DCCs,according to the high correlation coefficient, was found in the region 10°–20° east and 5°–10° south of the center of the cyclones. The potential relationship between DCCs and cyclones regarding their relative locations and circulation conditions was also identified by a case study. Deep clouds were generated in the warm conveyor belt by strong updrafts from baroclinic flows. The updrafts intensified when latent heat was released during the adjustment of the cyclone circulation current. This indicates that the dynamics of cyclones are the primary energy source for DCCs over the NP in winter.     

Classification of precipitation types using fall velocity-diameter relationships from 2D-video distrometer measurements

Fall velocity-diameter relationships for four different snowflake types (dendrite, plate, needle, and graupel) were investigated in northeastern South Korea, and a new algorithm for classifying hydrometeors is proposed for distrometric measurements based on the new relationships. Falling ice crystals (approximately 40 000 particles) were measured with a two-dimensional video disdrometer (2DVD) during a winter experiment from 15 January to 9 April 2010. The fall velocity-diameter relationships were derived for the four types of snowflakes based on manual classification by experts using snow photos and 2DVD measurements: the coefficients (exponents) for different snowflake types were 0.82 (0.24) for dendrite, 0.74 (0.35) for plate, 1.03 (0.71) for needle, and 1.30 (0.94) for graupel, respectively. These new relationships established in the present study (PS) were compared with those from two previous studies. Hydrometeor types were classified with the derived fall velocity-diameter relationships, and the classification algorithm was evaluated using 3× 3 contingency tables for one rain-snow transition event and three snowfall events. The algorithm showed good performance for the transition event: the critical success indices (CSIs) were 0.89, 0.61 and 0.71 for snow, wet-snow and rain, respectively. For snow events, the algorithm performance for dendrite and plate (CSIs = 1.0 and 1.0, respectively) was better than for needle and graupel (CSIs = 0.67 and 0.50, respectively).