微型近红外光谱仪测量北极积雪覆盖海冰内部太阳辐照度可行性研究   总被引：1，自引：1，他引：0  

南立文  王晓萍  王杭州  周宏亮  陈鹰 《海洋学报(英文版)》2020,39(9):115-124

The extremely low temperature, high humidity and limited power supply pose considerable challenges when using spectrometers within the Arctic sea ice. The feasibility of using a miniature low-power near-infrared spectrometer module to measure solar radiation in Arctic sea ice environments was investigated in this study.Temperature and integration time dependences of the spectrometer module were examined over the entire target operating range of –50℃ to 30℃, well below the specified operating range of this spectrometer. Using these observations, a dark output prediction model was developed to represent dark output as a function of temperature and integration time. Temperature-induced biases in the saturation output and linear operating range of the spectrometer were also determined. Temperature and integration time dependences of the signal output were evaluated. Two signal output correction models were developed and compared, to convert the signal output at any temperature within the operating temperature range and integration time to that measured at the reference temperature and integration time. The overall performance of the spectrometer was evaluated by integrating it into a refined fiber optic spectrometry system and measuring solar irradiance distribution in the ice cover with thickness of 1.85 m in the Arctic during the 9th Chinese National Arctic Research Expedition. The general shape of the measured solar irradiance above the snow surface agreed well with that measured by other commercial oceanographic spectroradiometers. The measured optical properties of the sea ice were generally comparable to those of similar ice measured using other instruments. This approach provides a general framework for assessing the feasibility of using spectrometers for applications in cold environments.  相似文献   

利用FY-3A近红外资料反演水汽总量   总被引：4，自引：1，他引：3       下载免费PDF全文

胡秀清  黄意玢  陆其峰  郑婧 《应用气象学报》2011,22(1):46-56

该文介绍了利用搭载在FY-3A卫星上的中分辨率光谱成像仪 (MERSI) 的近红外 (NIR) 通道反演大气水汽总量 (PWV) 的方法。根据预先建立的查找表,大气水汽总量可以通过水汽通道与窗区通道的卫星测值相比反演得到。对MERSI近红外水汽通道灵敏度进行估算,结果表明:处于吸收带两翼的905 nm和980 nm通道对不同水汽量的敏感性表现比较接近,对较大水汽含量最为敏感;当水汽较弱时,强吸收的940 nm通道非常敏感。基于这3个通道对水汽含量敏感性的不同表现,采用3个通道水汽总量的加权平均值作为PWV产品的最终反演值。文中设计了水汽总量业务算法反演流程,并基于FY-3A/MERSI最新观测资料进行晴空大气水汽总量的业务处理生成试验,顺利生成MERSI单轨道水汽总量产品及日拼图中国区域产品和全球产品,同时生成多天合成产品,产品反映出MERSI具有较好的近红外水汽探测能力。将卫星反演结果与探空数据进行初步比对检验,显示卫星反演值有20%~30%系统性偏低,需要进一步改进反演查找表。  相似文献   

土壤粒径的光谱响应特性研究   总被引：1，自引：0，他引：1  

曾远文  段松江 《山东国土资源》2019,35(11)

以实验室制备的5个不同粒径水平的土壤样本和室内高光谱数据为基础,通过对光谱数据进行重采样、数学变换等预处理并进行单因素方差分析、相关性分析和回归分析,探讨土壤粒径的高光谱特性,建立了光谱数据预测土壤粒径的校正模型。结果表明,土壤粒径对反射光谱有显著的影响,波长越长影响越大;在全波段范围内土壤粒径和光谱数据都呈负相关关系,对原始光谱数据进行微分变换能增加其与土壤粒径的相关性;以反射率一阶微分建立的回归模型为反演土壤粒径的最佳模型,其建模决定系数■、预测决定系数■、预测相对偏差RPD分别为0.666,0.653,2.043,预测均方根误差RMSE为0.175。  相似文献   

用陆地卫星—5近红外图像观测胶州海况     

平仲良 《海洋与湖沼》1997,28(1):104-108,T001

对海洋上卫星测得的近红外波辐射反映的信息进行理论分析，表明卫星近红外波段图像上反映的海况信息，１９９６年１１月５日陆地卫星ＴＭ６图像显示胶州湾海表温度的波状分布，ＴＭ２，ＴＭ３，ＴＭ４波段彩色合成图像显示胶州湾的悬浮泥沙含量分布和泥沙运动。ＴＭ４图像显示在海洋波动和风力作用下的海况，并用实测潮汐资料，气象信息解译胶州湾海况，在胶州湾中，西部，悬浮泥沙含量较高，而ＴＭ４波段辐射值较低，图像阴暗，较高  相似文献   

基于ICA的漫射光相关谱血流分离算法研究          下载免费PDF全文

孙玲  白静  邸文奇  尚禹 《CT理论与应用研究》2022,31(6):809-820

血流是人体的一个重要生理参数,实时测量脑部、骨骼肌及乳腺等组织的血流对疾病诊断治疗及手术、重症监护有重要意义。近红外漫射光相关谱（DCS）是新兴的组织血流测量技术,利用DCS技术进行血流测量时,每个距离的光源-探测器（S-D）均含有不同程度的表层组织和深层组织的混合信号,其中表层信号对提取深层组织的血流有较大影响。本文结合N阶线性算法（NL算法）和独立成分分析算法（ICA）对DCS技术获取的近距离和远距离光学信号进行分离处理。计算机仿真表明,本文提出的算法可以较好地分离出表层和深层组织的血流信号,对今后DCS技术在临床的血流测量应用有重要潜力。   相似文献   

Noise reduction methods in the analysis of near infrared lunar occultation light curves for high angular resolution measurements     

Tapas Baug  Thyagarajan Chandrasekhar 《天文和天体物理学研究(英文版)》2013,(11):1363-1380

A lunar occultation （LO） technique in the near-infrared （NIR） provides angular resolution down to milliarcseconds for an occulted source, even with ground- based 1 m class telescopes. LO observations are limited to brighter objects because they require a high signal-to-noise ratio （S/N ~40） for proper extraction of angular diameter values. Hence, methods to improve the S/N ratio by reducing noise using Fourier and wavelet transforms have been explored in this study. A sample of 54 NIR LO light curves observed with the IR camera at Mt Abu Observatory has been used. It is seen that both Fourier and wavelet methods have shown an improvement in S/N compared to the original data. However, the application of wavelet transforms causes a slight smoothing of the fringes and results in a higher value for angular diameter. Fourier transforms which reduce discrete noise frequencies do not distort the fringe. The Fourier transform method seems to be effective in improving the S/N, as well as improving the model fit, particularly in the fainter regime of our sample. These methods also provide a better model fit for brighter sources in some cases, though there may not be a significant imorovement in S/N.  相似文献   

恒星形成区GGD12-15的近红外观测     

房敏  姚永强 《天文学报》2004,45(1):1-15

给出恒星形成区GGD12-15的宽波段JHK和窄波段H2v=1-0S(1)近红外成像观测．观测图像揭示了致密的年轻红外星团和与红外源成协的红外星云，并发现了以H2发射结表征的星团外流活动．大多数红外点源在光学波段不可见；对76颗红外点源的JHK′测光结果显示，有32颗具有红外超，其中5颗表现原恒星特征，表明分子云中的恒星形成活动很活跃．以B8光谱型作为大质量星分界，由色星等图估计出大质量星所占星团比例为-10％～26％．GGD12—15星团的K′星等分布的峰值位于15.0mag，并在13．0mag-16．0mag平坦分布；[H—K′]色分布的峰值出现在-0．7mag，在此以上更红的星团成分占70％．在GGD12-15区新发现的氢分子发射结集中在星团中心领域，其空间分布明显与剧烈的恒星形成活动相关；有5个发射结位于分子外流的中心区域，暗示其激发可能与分子外流同源．  相似文献   

Near—Infrared Imaging Observations of the Orion A—W Star Forming Region     

Jun－JieWang 《中国天文和天体物理学报》2002,2(3):260-265

We carried out near-infrared imaging observations of the Ori A-W region using the Italian 1.5m TIRGO infrared telescope at Gornergrat. A group of infrared objects is visible on the K band image, including an IRAS source (IRS 1). From its IRAS flux density the IRAS luminosity is derived to be 45L⊙, which shows that IRS 1 is a low-mass protostar. By superimposing the position of the VLA H2O maser on the K image, we can identify the less evolved object IRS 1 as the excitation source of the H2O maser, within a projected distance of 470AU. This would be evidence that the maser effect is associated with the youngest phase of stellar evolution. The first probable HH object candidate in the Ori A-W region is discovered from the H2 S(1) 1-0 observation. Comparing the position of the H2O maser with the direction of the molecular hydrogen emission in the region, we suggest that the observed H2O maser could be tracing the circumstellar disk of IRS 1.  相似文献   

20颗依巴谷碳星的近红外测光     

陈培生  杨孝鸿  汪洵浩 《天文学报》2003,44(2):110-115

对20颗依巴谷(Hipparcos)卫星所观测的碳星作了近红外JHK测光，由近红外观测结果估算了其在K波段的热改正BCK和视热星等mbpl以及有效温度Te，结合依巴谷卫星所得视差，得到其中一些星的绝对热星等Mbol。  相似文献   

巨早型星系的近红外谱合成     

周旭 《天体物理学报》1992,12(4):308-323

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