西北太平洋多源微波辐射计海表温度数据交叉比对分析

海表温度产品是研究全球海洋大气系统的重要数据源,在海洋相关领域的研究和应用方面具有重要价值。以西北太平洋海域为研究区域,本文对2013年和2014年3个微波辐射计海表温度产品(AMSR-2,TMI和WindSat)的产品特性和Argo浮标进行了真实性检验,并对3个传感器数据进行了交叉比对分析,具体涉及海表温度分布、温度梯度分布、观测点分布、匹配点分布、平均偏差分布、均方根误差分布、统计分析结果的逐月演变和海表温度误差棒分析。结果表明,3个微波辐射计在空间尺度上都能比较一致地反映西北太平洋海域的海表温度变化趋势。但遥感数据与浮标数据却存在季节性变化和昼夜差异,其中冬季微波数据与浮标数据的平均偏差和均方根误差较小,降轨数据与浮标数据的结果更接近。AMSR-2的海表温度数据质量比TMI和WindSat的海表温度数据更接近Argo数据。相比于WindSat和TMI,AMSR-2和TMI的海表温度数据质量更为接近,但是由于受到近岸陆地信号干扰,AMSR-2和TMI离岸100 km以内海域的数据应当慎用。     

黄海、东海上空春季气溶胶光学特性观测分析

2003年春季国家卫星海洋应用中心等几家单位在黄海和东海海区进行了为期40 d的二类水体信息测量试验,试验中使用手持太阳辐射计对海区上空大气光学特性进行了观测,并获得了大量晴空天气条件下的大气光学数据.利用本次试验获取的测量数据得到了黄海、东海海区春季的大气气溶胶光学特性,其中包括气溶胶光学厚度和气溶胶粒子谱分布.采用Langley方法对测量得到的太阳直射辐射量进行处理得到了海区上空气溶胶光学厚度,利用得到的气溶胶光学厚度来反演气溶胶粒子谱分布.反演结果表明无云情况下黄海、东海上空的气溶胶光学厚度在0.2~0.4左右,且气溶胶粒子谱分布的变化趋势也很接近;海区上空霾层较厚时测量得到的气溶胶光学厚度明显增大,最大接近0.8;气溶胶粒子谱分布的变化趋势发生了明显的变化.     

3维成像微波高度计风速反演

随着航天技术的发展和新型微波载荷的发射(如3维成像高度计),越来越多的小入射角海洋观测雷达将投入运行,如何有效地利用这些小入射角的后向散射数据成为研究的热点课题。利用TRMM(Tropical Rainfall Measuring Mission)的PR(Precipitation Radar)后向散射系数NRCS(Normalized Radar Cross Section)数据对小入射角情况下的海面风速反演方法和风速反演精度进行研究,并对风速反演性能进行统计分析。基于无雨条件下的PR海面后向散射数据,建立小入射角情况下的风速反演算法和经验的GMF模型。风速反演结果分别与浮标、ASCAT进行交叉比对。结果表明:反演风速的偏差小于0.28 m/s,标准差小于1.51 m/s;在中等风速条件下,反演风速的偏差和标准差均小于低风速条件和高风速条件;0°—8°入射角范围内的风速反演精度明显优于8°—12°入射角范围的风速反演精度。     

基于现场观测数据的HY-2A卫星有效波高校正研究

Significant wave height(SWH) can be computed from the returning waveform of radar altimeter, this parameter is only raw estimates if it does not calibrate. But accurate calibration is important for all applications, especially for climate studies. HY-2a altimeter has been operational since April 2012 and its products are available to the scientific community. In this work, SWH data from HY-2A altimeters are calibrated against in situ buoy data from the National Data Buoy Center(NDBC), Distinguished from previous calibration studies which generally regarded buoy data as "truth", the work of calibration for HY-2A altimeter wave data against in situ buoys was applied a more sophisticated statistical technique—the total least squares(TLS) method which can take into account errors in both variables. We present calibration results for HY-2A radar altimeter measurement of wave height against NDBC buoys. In addition, cross-calibration for HY-2A and Jason-2 wave data are talked over and the result is given.     

南海海平面长期变化及其趋势研究

On the basis of the satellite maps of sea level anomaly(MSLA) data and in situ tidal gauge sea level data,correlation analysis and empirical mode decomposition(EMD) are employed to investigate the applicability of MSLA data,sea level correlation,long-term sea level variability(SLV) trend,sea level rise(SLR) rate and its geographic distribution in the South China Sea(SCS).The findings show that for Dongfang Station,Haikou Station,Shanwei Station and Zhapo Station,the minimum correlation coefficient between the closest MSLA grid point and tidal station is 0.61.This suggests that the satellite altimeter MSLA data are effective to observe the coastal SLV in the SCS.On the monthly scale,coastal SLV in the western and northern part of SCS are highly associated with coastal currents.On the seasonal scale,SLV of the coastal area in the western part of the SCS is still strongly influenced by the coastal current system in summer and winter.The Pacific change can affect the SCS mainly in winter rather than summer and the affected area mostly concentrated in the northeastern and eastern parts of the SCS.Overall,the average SLR in the SCS is 90.8 mm with a rising rate of(5.0±0.4) mm/a during1993–2010.The SLR rate from the southern Luzon Strait through the Huangyan Seamount area to the Xisha Islands area is higher than that of other areas of the SCS.     

中国海洋卫星雷达高度计海上定标场建设初探

文章通过对卫星雷达高度计定标方法和定标内容的描述,跟踪调研国际上业务化的高度计定标场的配置和定标结果,提出我国海洋卫星高度计定标场建设基本思路,同时对定标场周边海区影响高度计定标的地球物理参数和水文气象参数进行初步分析,确定我国海上定标场的基本配置方案,将为我国海洋卫星雷达高度计海上定标场建设提供基本依据和参考。     

基于波形分类和子波形提取的雷达高度计近海波形重构算法

雷达高度计是测量海洋动力参数的重要传感器,为解决雷达高度计在近海测量数据不可用的问题,基于大量波形的分析及已有波形重构算法的比较,本文提出了一种基于波形分类和子波形提取的近海波形重构算法（OceanCS）.采用了验潮站的实测水位以及浮标的实测有效波高数据对算法的结果进行了验证.结果表明,本文提出的算法在近海的回波波形处理方面要优于其他五种算法（海洋算法、OCOG算法、Ice-2算法、Beta5算法和阈值算法）,并且不仅可反演海面高度、还可反演有效波高.通过对高度计的近海回波波形进行重构处理,可以提高近海测高数据的数量和质量.     

利用最冷目标地物替代法计算Jason-2微波辐射计的年度漂移

本文研究最冷目标地物替代法计算Jason-2微波辐射计JMR年度漂移。针对Jason-2卫星微波辐射计(JMR),利用微波辐射计传输模型,建立JMR 3个通道的全球最低亮温观测值的理论计算模型,模拟其3通道全球地物观测最冷亮温;基于2008年—2012年Jason-2地球物理数据(GDR)产品中全球对地观测亮温序列和模型计算的最冷亮温,建立亮温序列的最小观测亮温统计模型,查找全球地物观测最冷亮温序列;根据地物年度变化特性,建立光谱分析模型,去除最冷亮温序列的年度谐波;去除年度谐波后,采用线性拟合的方法外推最冷亮温序列的理论最小值,并据此计算Jason-2微波辐射计仪器的年度漂移量。     

Extraction of internal wave amplitude from nautical X-Band radar observations

One of the most important parameters for oceanic internal waves (IWs) is their amplitude. We have developed a method to retrieve the IW amplitude from nautical X-Band radar images based on the KdV equation for continuous stratified finite depth system. We have also tested the method of measuring the amplitude of IWs from X-Band radar backscatter image sequences acquired on June 2009 in the northeastern South China Sea. The method was applied in several radar images. Experiments show that the retrieval amplitudes are consistent with the in-situ observational amplitudes of IWs by using the towed thermistor chain and conductivity-temperature-depth (CTD) profile. The uncertainty of the method is also discussed.     

利用中国GF-3卫星SAR和HY-2A卫星微波散射计的首次台风联合定量观测

<正>The typhoon,as a mature tropical cyclone that develops in the western part of the North Pacific Ocean with high wind speed and heavy rainfall,is one of the most lethal and costly of natural disasters for the densely populated countries of East Asia.It can be easily detected by space-borne sensors operated at microwave,visible or infrared bands(Liu et al.,2014).Synthetic Aperture Radar(SAR)is