大气气溶胶在很多生物地球化学循环中具有重要作用,但是由于它的来源广泛并且具有很大的时空变化,难以在全球范围内精确、实时确定气溶胶的性质、组成及时空分布,因而对大气气溶胶的研究依赖于监测手段的发展。对大气气溶胶实验观测的...大气气溶胶在很多生物地球化学循环中具有重要作用,但是由于它的来源广泛并且具有很大的时空变化,难以在全球范围内精确、实时确定气溶胶的性质、组成及时空分布,因而对大气气溶胶的研究依赖于监测手段的发展。对大气气溶胶实验观测的观测方法和测量仪器有很多,而对地观测卫星利用其特有的优势,可以实现对气溶胶的大范围、实时探测,促进了大气气溶胶这一边缘学科的研究发展。简要回顾了对地观测系统(E arth Observ ing System)的发展历程,然后介绍了对地观测卫星遥感气溶胶的发展及现状,对国际新一代对地观测系统在气溶胶遥感方面的应用现状做了详细的描述和总结。展开更多
The Moderate Resolution Imaging Spectroradiometer （MODIS） is one of the key instruments for NASA＇s Earth Observing System （EOS）, currently operating on both the Terra and Aqua satellites. The MODIS is a major adv...The Moderate Resolution Imaging Spectroradiometer （MODIS） is one of the key instruments for NASA＇s Earth Observing System （EOS）, currently operating on both the Terra and Aqua satellites. The MODIS is a major advance over the previous generation of sensors in terms of its spectral, spatial, and temporal resolutions. It has 36 spectral bands： 20 reflective solar bands （RSB） with center wavelengths from 0.41 to 2.1 μm and 16 thermal emissive bands （TEB） with center wavelengths from 3.7 to 14.4 μm, making observations at three spatial resolutions： 250 m （bands 1-2）, 500 m （bands 3-7）, and lkm （bands 8-36）. MODIS is a cross-track scanning radiometer with a wide field-of-view, providing a complete global coverage of the Earth in less than 2 days. Both Terra and Aqua MODIS went through extensive pre-launch calibration and characterization at various levels. In orbit, the calibration and characterization tasks are performed using its on-board calibrators （OBCs） that include a solar diffuser （SD） and a solar diffuser stability monitor （SDSM）, a v-grooved flat panel blackbody （BB）, and a spectro-radiometric calibration assembly （SRCA）. In this paper, we present an overview of MODIS calibration and characterization activities, methodologies, and lessons learned from pre-launch characterization and in-orbit operation. Key issues discussed in this paper include in-orbit efforts of monitoring the noise characteristics of the detectors, tracking the solar diffuser and optics degradations, and updating the sensor＇s response versus scan angle. The experiences and lessons learned through MODIS have played and will continue to play major roles in the design and characterization of future sensors.展开更多
文摘大气气溶胶在很多生物地球化学循环中具有重要作用,但是由于它的来源广泛并且具有很大的时空变化,难以在全球范围内精确、实时确定气溶胶的性质、组成及时空分布,因而对大气气溶胶的研究依赖于监测手段的发展。对大气气溶胶实验观测的观测方法和测量仪器有很多,而对地观测卫星利用其特有的优势,可以实现对气溶胶的大范围、实时探测,促进了大气气溶胶这一边缘学科的研究发展。简要回顾了对地观测系统(E arth Observ ing System)的发展历程,然后介绍了对地观测卫星遥感气溶胶的发展及现状,对国际新一代对地观测系统在气溶胶遥感方面的应用现状做了详细的描述和总结。
文摘The Moderate Resolution Imaging Spectroradiometer （MODIS） is one of the key instruments for NASA＇s Earth Observing System （EOS）, currently operating on both the Terra and Aqua satellites. The MODIS is a major advance over the previous generation of sensors in terms of its spectral, spatial, and temporal resolutions. It has 36 spectral bands： 20 reflective solar bands （RSB） with center wavelengths from 0.41 to 2.1 μm and 16 thermal emissive bands （TEB） with center wavelengths from 3.7 to 14.4 μm, making observations at three spatial resolutions： 250 m （bands 1-2）, 500 m （bands 3-7）, and lkm （bands 8-36）. MODIS is a cross-track scanning radiometer with a wide field-of-view, providing a complete global coverage of the Earth in less than 2 days. Both Terra and Aqua MODIS went through extensive pre-launch calibration and characterization at various levels. In orbit, the calibration and characterization tasks are performed using its on-board calibrators （OBCs） that include a solar diffuser （SD） and a solar diffuser stability monitor （SDSM）, a v-grooved flat panel blackbody （BB）, and a spectro-radiometric calibration assembly （SRCA）. In this paper, we present an overview of MODIS calibration and characterization activities, methodologies, and lessons learned from pre-launch characterization and in-orbit operation. Key issues discussed in this paper include in-orbit efforts of monitoring the noise characteristics of the detectors, tracking the solar diffuser and optics degradations, and updating the sensor＇s response versus scan angle. The experiences and lessons learned through MODIS have played and will continue to play major roles in the design and characterization of future sensors.
