SWDC-4A联合POS进行集成传感器定向研究

主要介绍利用国产轻型组合宽角数字测绘相机SWDC-4A联合POS搭载轻型飞机A2C进行航测试验研究,探讨相机联合POS进行集成传感器定向测图的精度。试验采用将POS数据解算的定位定向参数参与到摄影测量区域网平差中,采用统一的数学模型和算法确定像片精确外方位元素的方法,并以常规空三结果对其进行验证,实验结果表明：采用地面元分辨率为6厘米的航摄影像,通过33个地面检查点的验证,表明SWDC-4A联合POS的集成传感器定向满足1:500测图要求。     

Glitch effects in ISOCAM Long Wave detector

One of the main limitations to the sensitivity of observations carried out withthe ISOCAM infrared camera comes from the responsivity variations and glitchescaused by impacts of charged particles. After more than 28 months of successfuloperations, the predicted glitch rate has been re-evaluated and compared toin-flight measurements. Glitch properties have been studied in orderto improve the removal algorithms, and thus the ultimate sensitivity of ISOCAM.All informations about the glitch phenomenon are very useful in order toprepare next space experiments.     

Cosmic Ray Effects on the ISOCAM Long Wave Detector

The ISOCAM detector is subjected to transient effects induced bycosmic rays, the so-called glitches. This paper is focused onthe ISOCAM long wave detector. The predicted glitch rates havebeen re-evaluated by taking into account secondary particlesproduction in the materials surrounding the LW detector. We showin this preliminary study that the difference between thepreviously predicted glitch rate and the observed rate may beexplained by secondary particles.     

The transient behaviour of the long wavelength channel of ISOCAM

The detector of the long wavelength channel of the ISOCAMcamera on-board the Infrared Space Observatory is a Galliumdoped Silicon photo-conductor hybridized by Indium bump. Itpresents systematic memory effects of the response which canbias the photometry by a factor of typically 40%. The main features of the response after flux variations are discussed. A simple empirical model actually used to correct systematically the data with a photometric accuracy of 5–10% is detailed.     

亚洲两个季风区大气季节内振荡的比较分析

本文利用ECMWF逐日再分析资料(1961～2000年),主要从结构和水平传播包括经向传播和纬向传播方面对南海和南亚两个季风区的30～60天振荡进行了比较分析.研究结果发现,两个季风区的大气季节内振荡都存在明显的年际变化,但并没有出现同相或反相的变化关系.两个季风区ISO在结构上既有相似的地方也有不同点,在垂直结构上都...     

Titan's 3-micron spectral region from ISO high-resolution spectroscopy

The near-infrared spectrum of Titan, Saturn's largest moon and one of the Cassini/Huygens' space mission primary targets, covers the 0.8 to 5 micron region in which it shows several weak CH₄ absorption regions, and in particular one centered near 2.75 micron. Due to the interference of telluric absorption, only part of this window region (2.9-3.1 μm) has previously been observed from the ground [Noll, K.S., Geballe, T.R., Knacke, R., Pendleton, F., Yvonne, J., 1996. Icarus 124, 625-631; Griffith, C.A., Owen, T., Miller, G.A., Geballe, T., 1998. Nature 395, 575-578; Griffith, C.A., Owen, T., Geballe, T.R., Rayner, J., Rannou, P., 2003. Science 300, 628-630; Geballe, T.R., Kim, S.J., Noll, K.S., Griffith, C.A., 2003. Astrophys. J. 583, L39-L42]. We report here on the first spectroscopic observations of Titan covering the whole 2.4-4.9 μm region by two instruments on board the Infrared Space Observatory (ISO) in 1997. These observations show the 2.75-μm window in its complete extent for the first time. In this study we have also used a high-resolution Titan spectrum in the 2.9-3.6 μm region taken with the Keck [Geballe, T.R., Kim, S.J., Noll, K.S., Griffith, C.A., 2003. Astrophys. J. 583, L39-L42; Kim, S.J., Geballe, T.R., Noll, K.S., Courtin, R., 2005. Icarus 173, 522-532] to infer information on the atmospheric parameters (haze extinction, single scattering albedo, methane abundance, etc.) by fitting the methane bands with a detailed microphysical model of Titan's atmosphere (updated from Rannou, P., McKay, C.P., Lorenz, R.D., 2003. Planet. Space Sci. 51, 963-976). We have included in this study an updated version of a database for the CH₄ absorption coefficients [STDS, Wenger, Ch., Champion, J.-P., 1998. J. Quant. Spectrosc. Radiat. Transfer 59, 471-480. See also http://www.u-bourgogne.fr/LPUB/TSM/sTDS.html for latest updates; Boudon, V., Champion, J.-P., Gabard, T., Loëte, M., Michelot, F., Pierre, G., Rotger, M., Wenger, Ch., Rey, M., 2004. J. Mol. Spectrosc. 228, 620-634]. For the atmosphere we find that (a) the haze extinction profile that best matches the data is one with higher (by 40%) extinction in the atmosphere with respect to Rannou et al. (2003) down to about 30 km where a complete cut-off occurs; (b) the methane mixing ratio at Titan's surface cannot exceed 3% on a disk-average basis, yielding a maximum CH₄ column abundance of 2.27 km-am in Titan's atmosphere. From the derived surface albedo spectrum in the 2.7-3.08 micron region, we bring some constraints on Titan's surface composition. The albedo in the center of the methane window varies from 0.01 to 0.08. These values, compared to others reported in the other methane windows, show a strong compatibility with the water ice spectrum in the near-infrared. Without confirming its existence from this work alone, our data then appear to be compatible with water ice. A variety of other ices, such as CO₂, NH₃, tholin material or hydrocarbon liquid cannot be excluded from our data, but an additional unidentified component with a signature around 2.74 micron is required to satisfy the data.     

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GPS／INS直接定向精度分析

近年来,GPS／INS融合技术在国内逐渐被应用于航空摄影测量中,利用其直接获得外方位元素,从而减少外业控制点。通过试验,在DMC数码相机同高精度的GPS／INS系统联结下,直接获取了试验区的外方位元素,并对GPS／INS数据直接定向的精度进行分析和总结,得出了一些有益的结论。     

热带大气季节内振荡的一个数值模拟研究

文中分析了中国科学院大气物理研究所全球气候谱模式ALGCM (R4 2L9) 12a(1978～ 1989年 )积分的逐日输出结果 ,并与 1978～ 1989年的逐日NCEP资料对照 ,以此对热带季节内振荡 (30～ 6 0d振荡 )进行数值模拟研究。分析表明 ,该模式在热带地区可以模拟出明显的季节内振荡 (ISO)的准周期信号 ,并抓住了热带ISO的基本传播特征 ,能较好地再现东、西半球传播速度的差异 ,同时模式模拟存在东传要好于西传 ,冬、春季的模拟要好于夏、秋季的现象。该模式模拟的热带ISO的强度较许多大气模式明显提高 ,尤其是对 2 0 0hPa上ISO动能强度的模拟。模式基本模拟出了ISO低层辐合、高层辐散的水平风场特征。模式较好地再现了热带ISO纬向风的垂直结构。此外 ,观测资料表明热带ISO在冬、春强 ,而夏、秋弱的季节性倾向与ISO的年际变化相联系 ,模拟的ISO在季节性倾向偏差上表现为冬、夏相对强 ,而春、秋相对弱。垂直速度、散度、水汽等物理量的配置同NCEP资料的结构特征仍有明显差异 ,模拟的ISO空间分布也不太理想 ,表明要很好模拟ISO结构和空间分布特征 ,还须做不少工作。