海面微波辐射特性测量与分析

在对海面微波辐射特性现场测量和数据处理的基础上,结合对海面微波辐射理论的初步分析,研究了各种环境参数以及辐射计参数与海洋微波谱特性的相关关系,为海洋微波遥感 资料的分析和解译提供了基础数据。测量结果表明了辐射计参数和环境要素对海面微波辐射特性的影响,而这些影响因素在分析、解译遥感资料时是必需考虑的因素。     

海面风速微波散射测量与分析

为了深入研究海面风的微波散射特性 ,利用海洋石油平台和飞机作为仪器的工作平台 ,对海面微波散射特性进行了测量 ,并应用统计分析方法 ,对测量数据作处理分析。结果表明 ,海面微波后向散射系数 (σ°)值与海面风速成线性关系 ,随风速增大而增大。同时 ,σ°值与夹角及散射计天线入射角、极化方式有关。结合对海面微波散射算法中 Phillips模式的分析比较 ,得到 Phillips模式的计算值与实测值变化趋势一致的结果     

水面油膜微波辐射特性实验室测量与分析

要实现利用微波辐射计对海面溢油的厚度等参数进行遥感监测，必须先对水面油膜的微波辐射特性进行研究，以便为传感器的设计和遥感资料的解译提供依据。在实验室条件下，利用“灰体室”的环境条件及测量方法，测试了原油、燃料油和食用植物油膜的微波发射率与油膜厚度之间的关系，并对测量结果进行分析和讨论。为实际应用提供技术资料。     

我国首台天基微波散射计测量海面风场的应用研究

介绍了微波散射计测量海面风场的原理和反演算法,并将此算法应用于我国首台天基微波散射计.获得了我国自主资料的第一幅海面风场图.     

相对海面变化与江苏中部辐射沙洲的变化动态

随着海面上升,岸外沙洲可以做出适当调整以适应逐渐变化的动力条件。如果沙洲能够得到足够的泥沙供给,淤积速率可以与相对海面上升速率同步或超过相对海面上升速率,那么沙洲就能够继续存在,相反则会逐渐消失。江苏中部辐射沙洲整体缺少外来泥沙供给,再加上海面上升和不断的围垦活动,辐射沙洲的总面积势必逐渐缩小,但巨大的沙脊群内部的调节作用可以使一部分沙洲在海面上升过程中得以淤高,并在一定时期内继续存在。     

一维综合孔径微波辐射计遥感海面温度的敏感性分析

一维综合孔径微波辐射计能够有效提高观测的空间分辨率,其观测入射角通常在0°~55°范围内变化。为了开发适用于一维综合孔径微波辐射计的海面温度反演算法,需要评估其观测亮温对海洋大气环境要素的敏感性。利用海面发射率模型和大气辐射传输模型,构建了适用于一维综合孔径微波辐射计的微波海洋大气辐射传输模式,研究了C波段垂直和水平极化微波辐射亮温在不同入射角下对海洋大气环境要素的敏感性变化情况,并定量计算了相应的敏感系数。结果表明:垂直和水平极化亮温对海洋大气环境要素的敏感性表现出不同的特性。随着入射角的增大,垂直极化亮温对海面温度的敏感性增强,对海面风场的敏感性相对减弱;水平极化亮温则相反。由大气水汽含量和云液态水含量误差引入的垂直和水平极化亮温误差随入射角增大而增大,但是,即使在55°的大入射角下垂直和水平极化亮温误差仍小于0.12 K。对于海面温度反演精度优于1 K的要求,一维综合孔径微波辐射计的测温精度需优于0.6 K。研究结果对于一维综合孔径微波辐射计海面温度反演算法的研究和载荷设计具有一定的理论指导意义。     

海洋白浪与海面摩擦速度的直接同步测量及其结果分析

本文报告首次进行的海洋白浪、泡沫和沫流带与海面摩擦速度的直接同步测量结果.由此结果得海洋白浪覆盖率W_c与海面摩擦速度U_*的经验关系为W_c=1.34×10^-5U_*^1.93.这一关系式支持白浪覆盖率正比于海面风应力的论断;显著不同于白浪覆盖率正比于摩擦速度3次方的物理分析结果.基于此经验关系式,还对白浪在海-气交换中的作用进行了讨论.     

红外和微波辐射计反演海表面温度的比较

介绍了红外辐射计和微波辐射计测量海表面温度的原理,分析了它们各自在反演海表面温度时的差异。在全球范围的海表面温度的遥感监测中,红外辐射计和微波辐射计的遥感精度受到多种因素影响。传感器本身的噪音、算法反演精度、传感器分辨率、搭载卫星的全球覆盖率等自身因素使辐射计的探测资料产生差别;大气状况、海面风速、测量海洋不同深度海水的表征温度等外界因子也同时影响着红外辐射计和微波辐射计的遥感精度。了解红外波段和微波波段的辐射计在各方面的优劣,有助于发挥各自特长,有效提高卫星监测海表面温度的精度。     

南黄海海面大气长波辐射计算方法的比较

利用了中国近海海洋综合调查与评价项目在南黄海区获得的海-气通量观测资料,对一些常用的计算海面大气长波辐射通量的经验公式进行了比较.结果表明,采用Clark和Josey各自提出的经验公式所得的计算结果与实测结果具有较好的一致性;而利用Bignami和Bunker提出的经验公式计算的海面大气长波辐射通量值与实测资料则存在着较大的误差.出现差别的原因可能与不同经验公式所选参数密切相关.     

Characteristics of Sea Surface Circulation and Eddy Field in the South China Sea Revealed by Satellite Altimetric Data

Temporal and spatial variations of sea surface circulation in the South China Sea were revealed with use of altimetric data provided by TOPEX/POSEIDON from December 1992 to October 1997. The estimated distribution of sea surface dynamic heights from altimetric data coincide well with the results of observation by Soong et al. (1995) and Chu et al. (1998). The RMS variability of sea surface dynamic height, which is obtained after tidal correction based on Yanagi et al. (1997), is high in the central part of the South China Sea, the Gulf of Tongking, the Sunda Shelf and the Gulf of Thailand. The high RMS variability in the Gulf of Tongking, the Sunda Shelf and the Gulf of Thailand is due to set up and set down of sea water by the East Asian monsoon, which is northeasterly during winter and southwesterly during summer. Also, the high RMS variability in the central part of the South China Sea is due to the variations of basin-wide circulation. The circulations are dominant in the central part of the South China Sea during summer and winter, an anticyclonic circulation during summer and a cyclonic circulation during winter. It is suggested that these circulations are controlled by the East Asian monsoon. Hence, there is an interannual variability of the basin-wide circulation associated with the variation of the East Asian monsoon.     

Long-Term 3D Hydrodynamic Modeling and Water Surface Statistics in Marmara Sea

Marmara Sea (MS) lies in the strategic crossroad, accommodating one of the busiest shipping routes in the world. In general, there is a two-layer current system in the MS and Turkish Straits system; the brackish waters originating in the Black Sea (BS) (18 PSU) moving southward to the Aegean Sea (AS), and a lower layer return flow of saltier Aegean waters (38.5 PSU) back to the BS. This variability poses a challenging task within the modeling perspective. In this research, 3D hydrodynamic modeling of MS is performed in order to investigate the spatial and temporal behavior of elevations between years 2000 and 2015. During the calibration process, the grid configuration, time step, and model coefficients (Manning bed roughness coefficient, a wind drag coefficient and horizontal viscosity are coefficients) are adjusted until the computed solution produced the best match to the observed data such as water surface elevations, velocities, and net discharges. To this end, a series of simulations are made. As a result, the observed and the predicted water surface elevations follow each other very closely. The developed model could accurately estimate the net discharge as well. In order to understand the behavior of MS, elevation pattern is calculated and depicted both on annual and seasonal scales. It is demonstrated that the influence of seasonally varying strong fresh water river discharges of Danube in BS have strong influence on the water mass characteristics of the MS.     

Variability of Sea Surface Circulation in the Japan Sea

Composite sea surface dynamic heights (CSSDH) are calculated from both sea surface dynamic heights that are derived from altimetric data of ERS-2 and mean sea surface that is calculated by a numerical model. The CSSDH are consistent with sea surface temperature obtained by satellite and observed water temperature. Assuming the geostrophic balance, sea surface current velocities are calculated. It is found that temporal and spatial variations of sea surface circulation are considerably strong. In order to examine the characteristics of temporal and spatial variation of current pattern, EOF analysis is carried out with use of the CSSDH for 3.5 years. The spatial and temporal variations of mode 1 indicate the strength or weakness of sea surface circulation over the entire Japan Sea associated with seasonal variation of volume transport through the Tsushima Strait. The spatial and temporal variations of mode 2 mostly indicate the temporal variation of the second branch of the Tsushima Warm Current and the East Korean Warm Current. It is suggested that this variation is possibly associated with the seasonal variation of volume transport through the west channel of the Tsushima Strait. Variations of mode 3 indicate the interannual variability in the Yamato Basin.     

中国南海海表面温度与对流关系初探

利用1985年1月～2009年7月月平均海表面温度(SST)和代表局地对流的对外长波辐射(OLR)资料,讨论中国南海海表面温度与局地对流之间的关系。结果显示,在气候平均意义下,南海对流增强所需的SST阈值为27℃,即当SST低于27℃时,南海OLR值高于240 W/m2,并且随SST的升高变化不大;SST超过27℃后,随着SST的升高,OLR迅速减小,对流强度不断增强。与一般热带海洋不同之处在于SST超过29.5℃后对流仍加强。冬季风阶段(10月～次年4月)SST值较低,对流受到抑制,即使在3、4月SST高于27℃时对流强度仍较弱;5月为南海夏季风爆发月,SST较4月仅升高1℃,但对流强度显著增强;夏季风阶段(6～9月)南海的高温暖水使对流在平均意义上维持高值,但对流的变化与局地SST变化之间的关系不明显。     

波浪和太阳短波辐射对渤、黄海夏季温度垂直结构的影响

基于普林斯顿(POM)模式,采用不同的垂直混合方案并考虑太阳短波辐射的作用,对渤海、黄海夏季垂直热结构进行了数值试验。试验结果表明,夏季波浪混合控制着渤海、黄海上混合层的形成,加入波浪混合能明显改善陆架浅海的夏季温度垂直结构。太阳短波辐射对渤海、黄海夏季上层垂直热结构有一定的作用,研究夏季海洋上层垂直热结构应该包括太阳短波辐射的影响,特别是对于水深相对较深的黄海。     

北黄海-渤海表层沉积物中浮游植物生物标志物的分布特征及指示意义

作为一种新的地球化学指标方法,多参数生物标志物法已被广泛应用于重建浮游植物生产力及群落结构。本文对北黄海-渤海表层沉积物中浮游植物生物标志物的分布进行了研究。通过对北黄海-渤海60个站位的调查研究发现,硅藻、甲藻和颗石藻这3种浮游植物的生物标志物含量高值区主要分布在泥质区,同TOC的分布模式类似。为了消除粒度和沉积速率对含量的影响,将这3种生物标志物含量分别与TOC做比值,结果发现相对含量高值区与高生产力区相对应。以这3种生物标志物的相对比例来分别指示浮游植物在北黄海-渤海的相对贡献变化,结果表明近岸区硅藻相对贡献高,这主要与硅藻在高浓度硅的情况下具有竞争优势有关;而由于对营养盐的竞争关系,甲藻相对贡献高值区处于远岸区。在北黄海中部发现高的颗石藻相对贡献,与黄海暖流入侵路径相对应。