中国卫星海洋观测系统及其传感器(1988—2025)

全面收集1988—2025年中国地球观测卫星(和飞船)计划,包括历史的、运行中的和列入未来计划的。详细介绍风云卫星系列(FY-n)、海洋卫星系列(HY-n)、资源卫星系列(ZY-n)、环境卫星系列(HJ-n)、中国遥感卫星系列(CRS-n)、灾害监测星座/北京小卫星(DMC/BJ-1)、神舟飞船系列(SZ-n)和天宫空间站系列(TG-n)等8个卫星(和飞船、空间站)系列。这些卫星(和飞船、空间站)系列都提供对海洋的观测,从而构成中国卫星海洋观测系统。按装载的传感器分类,进而给出中国的海色、海表温度、海面高度、海面风场和合成孔径雷达(SAR)卫星观测系统。对中国海洋观测卫星与国际海洋观测卫星装载的传感器性能作了比较和讨论,指出差距。列出目前在轨运行的中国海洋卫星观测系统38个传感器及其类似的国外卫星传感器。     

单点高频地波雷达资料估算潮能耗散的方法

使用嵊泗站所布设的地波雷达观测获取的径向流数据,以及嵊泗、芦潮港、岱山3个潮汐观测站水位资料,采用两点近似投影方法反演流场全矢量流速,并用T-Tide程序计算调和常数,分别计算O1、K1、M2、S2各分潮流速场及迟角场,并计算各点上的潮能通量及潮能耗散,得到嵊泗岛以西杭州湾口区域潮能耗散同地形存在良好对应关系,充分证明了采用地波雷达观测数据进行潮能耗散计算这一方法的可行性,供相关工作者作进一步研究和讨论.     

应用INSAR进行黄河三角洲地面沉降监测研究

在分析黄河三角洲的地面沉降状况及其对国民经济造成的影响的基础上,说明了对黄河三角洲进行地面沉降研究的必要性。综述了合成孔径雷达干涉测量的基本原理,针对近年来国内外干涉合成孔径雷达(INSAR)技术在地面沉降方面的研究和应用成果,分析了合成孔径雷达干涉测量技术应用于黄河三角洲地面沉降研究的可行性。     

全极化SAR图像中溢油极化特征研究

相比于单极化SAR图像,全极化SAR图像不仅能体现海面目标的几何特征、后向散射特征,还能体现目标的极化特征。因此,在溢油检测方面,极化SAR更具优势。特征提取作为溢油检测的关键步骤,直接影响到溢油检测的精度。在本文中,我们分析了全极化SAR图像中海面溢油的极化特征,如极化散射熵、平均散射角等。并提出了新的极化特征P,该特征参数能够反映海面目标电磁散射过程中布拉格散射机制和镜面散射机制的比例。为了研究极化特征溢油检测的能力,本文基于SIR-C/X-SAR和Radarsat-2全极化SAR图像开展了相关实验,并对比分析了溢油的多种极化特征。实验结果显示,在中低风速情况下,C波段溢油探测效果优于L波段;本文提出的极化特征P对海面散射机制敏感;基准高度和特征参数P在C波段比其他极化特征更适于溢油检测。     

2DVAR方法在台湾海峡海表流场融合中的应用

高频地波雷达可以提供沿岸大面积海表流的观测,但单个地波雷达只能提供径向流观测。本研究发展了一套二维变分(Two-Dimensional VARiational Method, 2DVAR)数据融合方法,将台湾海峡海域的地波雷达径向流数据与ROMS (Regional Ocean Model System)模式输出结果进行融合,得到一套较好的融合产品。结果显示,融合产品与雷达径向流的平均相对误差相较于模式输出与雷达径向流的平均相对误差由9.70%降低至1.54%。为进一步检验融合方法,设计了两种独立样本试验。试验一将雷达径向流按空间均匀划分为融合样本与独立样本,使用雷达融合样本与模式输出进行融合,此时融合结果的平均均方根误差(Root Mean Square Error, RMSE)相较于模式输出由0.41 m/s降低至0.19 m/s。试验二将雷达径向流和模式输出在空间上都均匀划分为融合样本与独立样本,对两种数据的融合样本进行融合,使用TC (Triple Collocation)方法估计模式输出、雷达观测与融合结果的误差方差,此时融合结果的平均误差方差最小,且其误差方差相对于独立的雷达径向流与模式输出在远岸处有明显减小。以上结果都表明融合数据更加接近实际海流,证明了2DVAR方法融合海表流的有效性。     

The sheltering effect of the Balearic Islands in the hindcast wave field

The sheltering effect of the Balearic Islands in the hindcast wave field was studied for typical Mediterranean wave situations of Llevant, Tramuntana and Mestral and for mild conditions such as the Garbí and Ponent winds. For this purpose, a third generation wave model was applied to the Mediterranean Sea and different patterns of the sheltered areas were found for the various representative situations depending on the wind variability and on the magnitude of the wind speed. From the analysis it was concluded that the sheltered zones created during storms generally persist for short periods of time of the order of 6 h, possibly reaching a maximum of 12 h. In contrast with earlier results obtained for swell dominated ocean areas, it was observed that in this area, due to the short fetches the sea states are mainly local wind seas and thus the wave field behind the islands depends on the local wind.     

Dominant climate factors influencing the Arctic runoff and association between the Arctic runoff and sea ice

介绍了星载雷达波谱仪的观测原理及误差分析模型,并在Hauser等提出的SWIM(sea wave investigation and monitoring by satellite)的基础上分析了波谱仪反演海浪谱的波长分辨率和角度分辨率。为了减小反演调制谱的波动,在数据处理过程中时域和波数域相邻单元的平均个数分别为10和8个。系统在不同的模式下工作,为了获取20°的角度分辨率,对调制谱平均次数分别取3次(模式1)、7次(模式2)、10次(模式3)。使用解析法和仿真法分析了SWIM工作在模式2时海浪谱观测的能量误差,两种方法的结果一致。对于给定的海浪条件,能量误差小于20%。     

Effect of atmospheric CO2 and solar activity on wind regime and water column stability in the major global upwelling areas

It is not clear whether global warming will favour or reduce global ocean phytoplankton productivity in coastal areas. Moreover, the relative contributions made by natural and/or anthropogenic factors to possible changes in phytoplankton productivity are not clear. As the relationship between primary production and alongshore wind forcing is well established for the Eastern Boundary Current (EBC) ecosystems, our aim is to determine whether the changes experienced over the last five decades (1958–2007) in atmospheric CO₂ and solar activity have been able to affect the wind regime and water column stability in the most biologically productive upwelling areas of California, Canary, Humboldt and Benguela. We approached the work by statistically studying the effect of solar activity and atmospheric CO₂ on surface alongshore wind stress and on water column stability. There was an increasing trend in wind stress and water column stability in all the upwelling areas over the period studied (with the single exception of stability in the California EBC system). The analysis of detrended series evidenced significant relationships between atmospheric CO₂ concentration and wind stress and water column stability in the coastal upwelling areas investigated. In addition, wind stress and stability data were found to be consistent, with negative linear relationships between wind stress and CO₂ in most of the sites in the Benguela, Canary and Humboldt regions associated, as expected, to positive relationships when water column stability is used as regressand. The results of the present study suggest that greenhouse gas forcing, independent of its well known general increasing trend, was able to decrease wind stress intensity and increase water column stability for the period 1958 to present in most of the sites of the four Eastern Boundary Ecosystems studied, with the one exception of the California region. Conversely, the impact of solar activity appeared to be quite low compared to the greenhouse gas forcing.     

The form of the asymptotic depth-limited wind-wave spectrum: Part III — Directional spreading

The directional spreading of both the wavenumber and frequency spectra of finite-depth wind generated waves at the asymptotic depth limit are examined. The analysis uses the Wavelet Directional Method, removing the need to assume a form for the dispersion relationship. The paper shows that both the wavenumber and frequency forms are narrowest at the spectral peak and broaden at wavenumbers (frequencies) both above and below the peak. The directional spreading of the wavenumber spectrum is bi-modal above the spectral peak. In contrast, the frequency spectrum is uni-modal. This difference is shown to be the result of energy in the wind direction being displaced from the linear dispersion shell. A full parametric relationship for the directional spreading of the wavenumber spectrum is developed. The analysis clearly shows that typical dispersion relationships are questionable at high frequencies and that such effects can be significant. This result supports greater attention being focussed on the routine recording of wavenumber spectra, rather than frequency spectra.     

投弃式海流剖面测量仪测量原理研究

根据投弃式海流剖面测量仪的测量原理建立了二维海流运动感生电场离散和连续模型,通过模型推导得到了海流与感生电场间的关系公式。通过对海流感生电磁场的分析,对海流测量的基本方法进行了研究,通过感生电磁场的量级的计算,确定了投弃式海流剖面测量仪研究的主要方向和关键技术。