基于北京一号影像的射阳河口无机氮磷营养盐监测研究

通过在射阳河口现场采集光谱和水样,将实测光谱重采样为北京一号的波段反射率并与可溶性无机氮（DIN）和可溶性无机磷（DIP）浓度作相关性分析,结果表明,北京一号的近红外和红波段与DIN和DIP浓度呈强烈的正相关,这反映了沉积物的再悬浮作用是该海域营养盐的重要来源,波段组合因子中与DIN、DIP浓度相关性高的主要是由近红外波段与绿波段以及红波段与绿波段的比值或差值构成的因子,其相关性高于单波段因子。最终选择因子F10（3,1）的三次多项式模型作为该海域DIN、DIP浓度定量反演模型。模型相对浓度较高的样本组（DIN≥200g/L,DIP≥20g/L）的预测精度分别为73.69%和73.45%,而该海域DIN、DIP浓度的均值远远超过了上述阈值,影像反演结果也与实际情况高度吻合,反映了模型在该海域的实际应用价值。     

The Demeter microsatellite and ground segment

The Demeter program is the first application of the Myriade microsatellite program conducted by the Cnes (French Space Agency) since 1997. The Myriade objective was to benefit from the miniaturization of the technologies to develop a product with a reduced size, weight and cost able to implement either scientific missions, demonstrators or operational applications in different areas: earth observation, astronomy, fundamental physics or telecommunications, within limited financial budget.The Demeter satellite was launched in end of June 2004, from Baikonour, aboard a Dnepr launcher, on a sun synchronous orbit at 710 km altitude. Its main scientific objectives are the detection and characterization of ionosphere electrical and magnetic disturbances in connection with a seismic activity.The scientific payload has been built by French scientific institutes (LPCE, CESR, CETP) involved in external and internal geophysics and by SSD/ESTEC (ESA). It is composed of several electrical and magnetic sensors, an ion spectrometer, an energetic particle analyzer and a Langmuir probe.The Demeter platform is designed in order to offer a high level of performances in terms of power, attitude and orbit control, data storage and transmission, flexibility. For example the large amount of scientific data is transmitted to the ground station with a high data rate telemetry link in X band.This paper describes the Demeter satellite and ground segment. It focuses on the specific design adaptations of the Myriade product for Demeter and it presents the preliminary in orbit platform performances.     

“航天清华一号”微小卫星影像湖泊信息提取——以艾比湖为例

简要介绍了航天清华一号(HT-1)微小卫星的主要参数,并以艾比湖景为例,用ENVI软件对图像进行条带噪声消除、显示增强、几何纠正、假彩色合成等处理。最后介绍了如何在获取的影像中进行水面信息、地物信息、地貌信息等多种湖泊信息的提取。