渤海海峡海岛站与沿岸站大风对比分析

统计了渤海海峡5个海岛站和3个沿岸站1年的大风资料,在每月大风日数、风速、年际和月际变化特征、主导风向等方面进行了对比分析,得出渤海海峡大风如下结论:大风的风力以6～7级为主,南部比北部更易出现大风,且风速也较大;出现大风的最高概率为57.5%,即平均不到2天就出现一次;海岛站与沿岸站大风风力极值相差最大为20.8 m/s;极大风风速43.2 m/s,创历史最高纪录;风速的月变化规律基本一致,呈现两峰两谷形势;大风年主导风向为NW-NNE,风速以偏北大风和偏南大风较大,而偏西风和偏东风较小;具有典型的季风性气候特征,冬季以偏北大风为主,夏季以偏南大风为主,春、秋季偏北大风和偏南大风交替出现;综合应用海岛站和沿岸站大风记录,能更加准确反映渤海海峡大风的气候特征。     

一种基于分割图斑的海岸带遥感图像分类方法

传统的基于象元的分类方法在处理海岸带这类动态多变、混杂度大的地物时常出现“椒盐现象”,难以矢量化形成专题图。提出了一种新的遥感图像分类方法——基于分割图斑的分类法,即选择一个合适的尺度,利用光谱信息按照一定的策略将图像分割为一系列的图斑,并确保图斑内大多数象元的光谱特征相近,分别对图斑内诸象元进行统计,求出各个波段的均值,用该均值替换图斑内所有象元的原始亮度值,这样分类时可以确保同一图斑内的所有象元被分到同一个类别中,从而有效地避免了“椒盐现象”,使分类结果便于矢量化成图,也便于对特定地物的提取。实验结果表明,该方法还能在一定程度上提高分类精度。     

A seasonal Markov chain model for the weather in the central Alps

The dynamics of daily weather types according to Schüepp's classification in the Alpine region is investigated by means of seasonal Markov chain models. A logit model is employed for the transition probabilities of the Markov chain. The parameters follow from a maximum likelihood estimation. A 1st‐ and a 2nd‐order Markov chain model are compared and found to yield very similar results. Model predictions are compared with counted frequencies of seasonally‐averaged joint probabilities for the occurrence of weather types at subsequent days, monthly‐averaged probabilities of a change of the weather type from one to the next day, and daily averages of the probabilities of occurrence of the different weather types. All these predictions coincide with the observations within the statistical limits. The only large deviations occur in the tails of the lengths distributions of uninterrupted episodes of the two most frequent weather types.     

A transition in weather over the Agulhas Current

Aircraft observations were used to investigate contrasting weather conditions over the northern edge of the warm Agulhas Current south of George, South Africa, during June 1989. A sea surface temperature front of 7°C over 10 km was observed near 35°S, 23°E. Surface-sensible and latent heat fluxes increased by a factor of five on the warm side. A deepening of the moist unstable layer was indicated by increased equivalent potential temperatures over the warm side. Most significantly, convectively generated turbulence, as inferred from variances in air pressure, increased exponentially with sea surface temperature and surface layer winds doubled south of 35°S. The sea state, initially smooth over the continental shelf, became rough seawards of the northern edge of the Agulhas Current. Numerical model simulations were performed to assess air-sea interactions. Model-simulated thermodynamic variables responded in close agreement with observations, but the increase in cross-frontal winds was not fully resolved. The aircraft observations provide evidence that the Agulhas Current affects the large-scale pressure field and may enhance the rain-bearing capacity of transient weather systems.     

渤海一次强阵性雷雨大风过程的诊断分析

利用中尺度天气预报数值模式、粗网格再分析资料、地面和高空常规观测资料,对2011年8月31日渤海地区一次强阵性雷雨大风天气过程中的大气资料进行了重建.根据该资料,分析了对流有效位能、水汽输送、假相当位温和湿位涡等物理量在这次强对流过程中的演变特征.结果表明,修正的对流有效位能可以提前对强对流不稳定天气做出指示,与850 hPa假相当位温θse=340 K高能暖湿气团所在的位置以及处于△θse＜0的位势不稳定区有明显对应关系.另外,水汽通量的辐合中心与雷雨大风天气发生的区域基本一致.而700hPa等压面上的湿位涡最大负值区的叠加位置也是雷暴发展的另一有利形势,MPV正负交界处带状区域出现了南压和东移,表明湿位涡的发展趋势对冷锋锋面移动的路径、速度有较为明确的指示意义,移动过程中,由于出现降水,同时还伴随了湿位涡负区减弱的特征.上述物理量为雷雨大风预报提供了部分客观判断依据,可作为预报员得出预报结论的辅助手段之一.     

海洋台站数据管理及动态发布系统的设计

针对目前我国海洋环境监测和预报工作的实际需求,采用B/S架构模式设计开发了一套基于JSP的海洋台站数据管理及动态发布系统。系统软件采用Java语言编写,保证了系统的跨平台性和可移植性;B/S模式保证了系统后期维护、管理和升级操作的方便性;Ajax技术的应用提高了网页的实时响应特性、提高了用户体验;数据库连接池的使用提高了数据库的连接性能。该系统已在国家海洋局闽东海洋环境监测中心建立的海洋监测示范系统试点投运半年,运行稳定可靠,综合效益明显。现场应用表明,该系统较好的完成了预期任务,具有较大的推广价值和应用前景。     

一种面向港口溢油监测的小型激光荧光遥测系统

目前,针对港口溢油巡航监测缺乏行之有效的技术手段。为探索激光诱导荧光光谱技术应用于港口溢油监测的可行性,以微型光纤光谱仪搭建小型激光荧光遥测实验系统,并对其性能进行测试分析。结果发现,在光谱仪曝光时间设为最小(1.11 ms)的情况下,环境光对荧光测量仍会产生影响,利用减背景法可以有效去除溢油荧光信号中环境光的影响;在相同条件下,系统测得不同油质溢油样品的荧光光谱表现出不同的光谱特征,轻质油较重质油的荧光峰蓝移、荧光更强;在上述环境光背景影响和光谱测量分析的基础上,进一步测试了系统的信号探测稳定性,结果显示,系统重复测量的相对标准偏差RSD=2.54%,表明该系统具有较好的信号探测稳定性。综上,基于微型光纤光谱仪的小型溢油激光荧光遥测系统可望在近岸港口溢油巡航监测中发挥重要作用。     

适用于快速远程检测海水中氰化物的方法研究

建立了一种适用于海洋远程快速检测氰化物的检测方法,设计了一体化检测装置,未来可搭载到无人艇上实现自动快速检测。针对最佳检测条件进行了一系列优化,得到最佳检测条件:对于100 mL的待测样品,加入酒石酸固体1.5 g;用1～2滴浓度为150 g/L的碳酸钠溶液浸润苦味酸试纸;加热温度80℃,加热时间10min。在最佳检测条件下,检测检出限达0.3mg/L。该方法实现了适用于海水氰化钠的远程检测,大大提高了检测效率,无需人员进入污染现场,安全性高。可广泛用于海洋危化品泄漏、湖泊污染、现场应急筛选等场合的水体样品快速检测。     

A study of the data transferability between two wave-measuring stations

This study concerns the possible interrelationships of wave data among wave-measuring stations. This study uses wave records collected at Station Pi-Tou-Chiao (PTC) from 1983 to 1988, and at Station Keelung (KL) from 1983 to 1988. Depending upon the amount of consecutive data missing in the records, three methods were used to estimate their values. The methods used for data completion are: interpolation, ARMA model, and O'Carroll [O'Carroll, F.M., 1984. Weather modelling for offshore operations. The Statistician, 33, 161–169.] model. Using monthly transfer functions (TFs) between these two stations, the interrelationships of the significant wave heights measured at PTC and KL were estimated, and the records of the two measuring stations were set to have equal lengths. Assessments of the proposed methods were carried out by comparing the mean values, standard deviations, skewness, and kurtosis of both the completed and estimated wave records. The results indicate that the proposed methodologies can be used to fill in data gaps and to transfer data from one station to another—both of these methodologies are needed in the study of oceanographic time series.     

A case study on fine weather in Western Antarctic Peninsula

1 INTRODUcrIONGreat Wall Station (62"I2'S, 58"57'W), the Chinese Antarctic statidn, situates atKing George IsIand of the western Antarctic Peninsula area with typicaI sulypolar oceancIimate. On the upper level, the area is in the polar front zone where the coId polar airand warm southern temper8te air meet; on the surface it is on one of the POlar cycIonepaths prevailing by cold westerly drift current. So it is frequentIy rainy and foggy insummer and bIowing-snowy and snow-stOrmy i…     

南极中山站地区航空飞行的天气条件

随着中国南极考察事业的不断发展,科考工作进一步深入,南极地区不同机型的各类飞行活动将日益增多。开展南极航空气象服务是确保飞行安全,提高科考效率的迫切需求。南极冰雪高原的地形复杂,天气多变且局地性强,但是航路和场站的气象资料积累很少,航空气象服务的困难较大。本文对南极中山站地区影响飞行安全的主要天气现象,中山站地区的适航时间,天气条件等进行了初步探讨。     

基于遥感反射比光谱的一种藻类识别方法

利用所得的甲藻门和硅藻门的17种藻类遥感反射比光谱,对其进行平滑、取倒数和归一化等预处理后,进行了四阶微分处理.根据聚类分析结果,甲藻门各藻种分为一类,而硅藻门的藻种分为另一类,这说明经上述处理后,甲藻门和硅藻门的差异性显著增大.将甲藻门和硅藻门的四阶微分光谱分别平均得到门类的特征光谱,并在原始数据中加入泥沙进行敏感性...     

A general purpose exact Rayleigh scattering look-up table for ocean color remote sensing

1 Introduction In the total radiance received by an ocean color remote sensor, over 80% radiance is the contribution being scattered by air molecule and aerosol, and a wa- ter-leaving radiance carrying the ocean color informa- tion is only a small part. T…     

极区冰基拖曳式海洋剖面浮标系统低功耗设计与实现

针对极区冰基拖曳式海洋剖面浮标长期稳定获取极区水文和气象数据的工作需求,进行了浮标系统的低功耗方案设计。该方案基于超低功耗51系列微处理器,根据最低功耗工作模式与最短工作时间原则,采用高效的电源管理机制对浮标系统各个部分的能量消耗进行合理的分配与管理,并应用了Argos卫星通讯模块ARGOS-3 PMT-RFM的BPSK调制低速数据传输模式,可有效降低浮标系统的整体能耗。该浮标在北极冰站上长达1年的运行情况表明该系统工作稳定,所采用的低功耗能量管理方案实现了浮标系统长期连续观测的需求。该浮标的成功试验和推广应用有助于极地研究人员更准确地分析海冰变化过程。     

河口悬浮泥沙浓度Sea WiFS遥感定量模式研究

利用海洋水色卫星 Seastar/SeaWiFS数据和准同步实测表层含沙量资料,建立长江口区悬浮泥沙遥感定量模式.通过“exact closed-form”算法对多时相SeaWiFS数据进行几何定位,并利用大气辐射传输简化理论对其进行大气校正,求得各波段遥感反射率;在完成投影变换和几何精校正之后,建立遥感参数与含沙量相关关系,得到长江口区悬浮泥沙遥感定量模式.     

A spectral response approach for detecting dominant phytoplankton size class from satellite remote sensing

An important goal in ocean colour remote sensing is to accurately detect different phytoplank- ton groups with the potential uses including the validation of multi-phytoplankton carbon cycle models; synoptically monitoring the health of our oceans, and improving our understanding of the bio-geochemical interactions between phytoplankton and their environment. In this paper a new algorithm is developed for detecting three dominant phytoplankton size classes based on distinct differences in their optical signatures. The technique is validated against an independent cou- pled satellite reflectance and in situ pigment dataset and run on the 10-year NASA Sea viewing Wide Field of view Sensor (SeaWiFS) data series. Results indicate that on average 3.6% of the global oceanic surface layer is dominated by microplankton, 18.0% by nanoplankton and 78.4% by picoplankton. Results, however, are seen to vary depending on season and ocean basin.     

最优插值法用于天气雷达测定区域降水量

本文通过数据模拟和实测资料分析，表明用最优插值法测量区域降水量的测量精度和变分法相当，而最优插值法对雨时计的分布和密度要求较低，计算处理也简单。     

空间分辨率对水深遥感反演的影响分析

遥感水深反演中空间分辨率的影响是一个重要的科学问题。本文使用东岛的QuickBird和WorldView-2多光谱影像及实测水深点进行实验研究,实验使用了原始空间分辨率（2.4/2m）以及4种降空间分辨率（4m,8m,16m和32m）的影像,使用相同的水深控制点开展水深遥感反演,并对水深反演结果使用相同的检查点进行精度验证。实验结果表明,随着空间分辨率由2.4/2m降低至4m,8m和16m,水深遥感反演的精度呈现出逐渐提高的趋势,进一步降低空间分辨率则会导致水深反演精度下降。当影像空间分辨率为16m时,水深反演结果误差最小且与实测水深值相关性最高,此时两景影像的水深反演平均相对误差分别21.2%和13.1%,相对于最大值分别降低了14.7%和2.9%;平均绝对误差分别为2.0m和1.4m,相对于最大值分别降低了1.0m和0.5m。本文研究结果为水深遥感反演研究与应用中遥感数据的选择提供了参考。