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排序方式: 共有755条查询结果,搜索用时 31 毫秒
331.
Christopher J. Mertens Jeremy R. Winick Richard H. Picard David S. Evans Manuel López-Puertas Peter P. Wintersteiner Xiaojing Xu Martin G. Mlynczak James M. Russell III 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
Thermospheric infrared radiance at 4.3 μm is susceptible to the influence of solar-geomagnetic disturbances. Ionization processes followed by ion-neutral chemical reactions lead to vibrationally excited NO+ (i.e., NO+(v)) and subsequent 4.3 μm emission in the ionospheric E-region. Large enhancements of nighttime 4.3 μm emission were observed by the TIMED/SABER instrument during the April 2002 and October–November 2003 solar storms. Global measurements of infrared 4.3 μm emission provide an excellent proxy to observe the nighttime E-region response to auroral dosing and to conduct a detailed study of E-region ion-neutral chemistry and energy transfer mechanisms. Furthermore, we find that photoionization processes followed by ion-neutral reactions during quiescent, daytime conditions increase the NO+ concentration enough to introduce biases in the TIMED/SABER operational processing of kinetic temperature and CO2 data, with the largest effect at summer solstice. In this paper, we discuss solar storm enhancements of 4.3 μm emission observed from SABER and assess the impact of NO+(v) 4.3 μm emission on quiescent, daytime retrievals of Tk/CO2 from the SABER instrument. 相似文献
332.
Swarvanu Dasgupta Ramesh P. Singh Menas Kafatos 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
Chlorophyll concentrations derived from satellite borne ocean color sensors data provide an idea of the distribution of phytoplanktons across the oceans which help us in understanding the spatial and temporal dynamics of phytoplanktons. The changes in the patterns of distribution and abundance of the planktons have significant impact on the entire ecosystem and play a key role in the global carbon cycle. In this paper, we have analyzed annual and seasonal chlorophyll concentrations retrieved from MODIS data for the periods March 2000–October 2003, which reveal the spatial and seasonal distribution of chlorophyll concentrations across the global oceans. Chlorophyll concentrations anomaly indicate that chlorophyll concentrations in almost all ocean regions responded similarly. 相似文献
333.
马文坡 《运载火箭与返回技术》2007,28(4):23-27
介绍了卫星光学遥图像获取与图像处理一体化优化设计的思路;运用通用像质方程(GIQE)对于利用小相对孔径光学系统和调制传递函数补偿(MTFC)方法得到的图像的品质与利用相对较大相对孔径光学系统得到的图像的品质进行了对比分析。 相似文献
334.
国外海洋盐度与土壤湿度探测卫星的发展 总被引:5,自引:2,他引:3
文章调查研究了国外海洋盐度与土壤湿度探测卫星发展情况、探测机理;重点对SMOS、Aquarius、SMAP等三颗最具代表性的土壤湿度和海洋盐度探测卫星进行了研究分析,比对了三颗卫星的主要技术指标,并总结了其技术发展特点和关键技术;最后结合我国技术基础对发展我国盐度与湿度卫星提出了建议。 相似文献
335.
Sven Kühl Walburga Wilms-Grabe Christian Frankenberg Michael Grzegorski Ulrich Platt Thomas Wagner 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2006,37(12):2247-II
The scanning imaging absorption spectrometer for atmospheric chartography was launched successfully onboard ENVISAT on March 1, 2002. It observes the solar radiation transmitted and backscattered from the atmosphere and reflected from the ground in nadir, limb and occultation viewing modes. Chlorine dioxide (OClO), an important indicator for stratospheric chlorine activation, can be measured in the UV spectral range by differential optical absorption spectroscopy (DOAS).
First results of the DOAS retrieval of OClO slant column densities from the SCIAMACHY nadir measurements are presented and compared to measurements of the global ozone monitoring experiment (GOME), which has successfully measured OClO since 1995. While SCIAMACHY operates in the same orbit, it measures ≈30 min earlier than GOME and has an increased spatial resolution (30 × 60 km2 compared to 40 × 320 km2 for GOME). 相似文献
336.
Willem W. Verstraeten Frank Veroustraete Walter Heyns Tom Van Roey Jan Feyen 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008,41(1):20-35
Uncertainty on carbon fluxes is determined by the uncertainties of ecosystem model structure, data and model parameter uncertainties and the temporal and spatial inaccuracy of the input data retrieval. The objective of this paper is to understand the error propagation and uncertainty of evaporative fraction (EF), soil moisture content (SMC) and water limited net ecosystem productivity (NEP). In this respect, C-Fix and spaceborne remote sensing are used for the ‘Brasschaat’ pixel. A simple model based on error theory and a Monte-Carlo approach are used. Different error scenarios are implemented to assess input uncertainty on EF, SMC and NEP as estimated with C-Fix. 相似文献
337.
Habibeh Valizadeh Alvan Farid Haydari Azad Shattri Mansor 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
Pre-earthquake physical and chemical interactions in the earth’s ground may cause anomalies in latent heat flux, air and surface temperature. Earthquakes occur when the energy accumulated in rocks releases. Sometimes, the movements of the ground cause ruptures in the earth’s surface and sometimes the two sides of an existing fault shift towards each other. In a structurally complex and inhomogeneous collision region such as the Iranian Plateau, seismicity is not the result of activity of a single fault but is due to energy discharge in fault zones hundreds of kilometers wide. 相似文献
338.
Simultaneous determination of aerosol- and surface characteristics from top-of-atmosphere reflectance using MERIS on board of ENVISAT 总被引:1,自引:0,他引:1
Wolfgang von Hoyningen-Huene Alexander A. Kokhanovsky John P. Burrows Veronique Bruniquel-Pinel Peter Regner Frederic Baret 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2006,37(12):2172-II
The determination of aerosol optical thickness (AOT) from nadir scanning multi-spectral radiometers, like SeaWiFS, MERIS or MODIS, requires the separation of spectral atmospheric and surface properties. Since SeaWiFS and MERIS do not provide information at 2.1 μm, like MODIS, the estimation of the surface reflectance cannot be made by the cross correlation approach described by Kaufman et al., 1997. The BAER approach (Bremen AErosol Retrieval), von Hoyningen-Huene et al., 2003, uses a linear mixing model of spectra for ‘green vegetation’ and ‘bare soil’, tuned by the NDVI, determining an apparent surface to enable this separation of aerosol and surface properties from VIS and NIR channels. Thus AOT can be derived over a wide range of land surfaces for wavelengths <0.67 μm. Using MERIS L1 data over Europe, the AOT retrieved is comparable with ground-based observations, provided by AERONET. Regional variation of AOT can be observed, showing the atmospheric variability for clear sky conditions by: large scale variation of aerosol turbidity, regional pollution, urban regions, effects of contrails and cases of aerosol-cloud interaction. Simultaneously with the spectral AOT also spectral surface reflectance is obtained, where all atmospheric influences have been considered (molecules, aerosols and absorbing gases (O3)) for channels with wavelengths <0.67 μm. The AOT is extrapolated by Angström power law to NIR channels and the atmospheric correction for land surface properties is performed, enabling the further investigation of land use and spectral land properties. 相似文献
339.
研究了光机扫描仪扫描条带宽度随扫描角变化的变化规律,并推导出扫描条带宽度变化量的计算公式.讨论了卫星侧摆成像时,计算条带宽度变化量的方法.最后,建立了扫面条带的数学模型,并对MODIS扫描条带宽度变化进行了仿真. 相似文献
340.