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71.
使用SBDART 辐射传输模式模拟EOS/MODIS 可见光和近ö短波红外通道的光学特性, 分析了使用这些通道进行云雾光学厚度和有效粒子半径反演的可行性, 建立了不同条件下的正演模拟辐射数据库, 在此基础上反演云雾光学厚度和有效粒子半径。敏感性研究表明, 不同波长的近/短波红外波段反射率对不同高度上的粒子敏感, 使用不同通道组合反演所得的有效粒子半径反映了云层不同高度上的粒子尺度特征。结合卫星数据和常规资料做了实例分析, 分析结果表明, 反演结果具有合理性。 相似文献
72.
TANG Junwu GU Xingfa NIU Shengli MA Chaofei & MIN Xiangjun . National Satellite Ocean Application Service 《中国科学E辑(英文版)》2005,(Z2)
The CBERS-02, the second satellite of China Brazil Earth Resources Satellite series, was launched on Oct. 21, 2002. Onboard the satellite, there are three major sensors, a CCD camera, a wide field imager and an infrared multispectral scanner (http://www. cresda.com). The purpose of this paper is to calibrate the CCD camera with a methodol- ogy of cross-calibration. The spatial resolution of the multispectal bands of CCD camera is 19.5 m, the swath is about 115 km. It is capable of side… 相似文献
73.
《中国科学E辑(英文版)》2005,(Z2)
Land surface evapotranspiration is one of the most important components in water cycle between earth and atmosphere, and plays a very important role in the atmosphere, hydrosphere, and biosphere of the planet. It is an urgent task to understand the evapotranspiration process over different surface types and conditions in agriculture, hydrogeology, forest, and ecology for the purpose of using water resources properly. Additionally, land surface evapotranspiration is a key parameter in the synop… 相似文献
74.
John C. Price 《Remote sensing of environment》2003,86(4):491-499
Nearly simultaneous reflectance data sets from the Landsat 7 Enhanced Thematic Mapper Plus (ETM+), at 30-m resolution, and the Terra satellite instrument MODIS, at 500-m resolution, are compared for their ability to map fractional coverage of surface types over large areas. Lower spatial resolution MODIS classification results are generally comparable those of ETM+, with discrepancies for some regions with mixed surface types. Analysis of laboratory and field spectra suggests an ambiguity, the “brightness ambiguity”, which can prevent accurate area estimation of pixels having two or more surface types. This ambiguity, plus general mathematical inversion issues, can account for the discrepancy. Thus, occasional high-resolution measurements, as from Landsat 7, are necessary to refine estimations of large area surface types from MODIS and similar lower spatial resolution instruments. 相似文献
75.
Scaling Gross Primary Production (GPP) over boreal and deciduous forest landscapes in support of MODIS GPP product validation 总被引:1,自引:0,他引:1
David P. Turner William D. RittsWarren B. Cohen Stith T. GowerMaosheng Zhao Steve W. RunningSteven C. Wofsy Shawn UrbanskiAllison L. Dunn J.W. Munger 《Remote sensing of environment》2003,88(3):256-270
The Moderate Resolution Imaging Radiometer (MODIS) is the primary instrument in the NASA Earth Observing System for monitoring the seasonality of global terrestrial vegetation. Estimates of 8-day mean daily gross primary production (GPP) at the 1 km spatial resolution are now operationally produced by the MODIS Land Science Team for the global terrestrial surface using a production efficiency approach. In this study, the 2001 MODIS GPP product was compared with scaled GPP estimates (25 km2) based on ground measurements at two forested sites. The ground-based GPP scaling approach relied on a carbon cycle process model run in a spatially distributed mode. Land cover classification and maximum annual leaf area index, as derived from Landsat ETM+ imagery, were used in model initiation. The model was driven by daily meteorological observations from an eddy covariance flux tower situated at the center of each site. Model simulated GPPs were corroborated with daily GPP estimates from the flux tower. At the hardwood forest site, the MODIS GPP phenology started earlier than was indicated by the scaled GPP, and the summertime GPP from MODIS was generally lower than the scaled GPP values. The fall-off in production at the end of the growing season was similar to the validation data. At the boreal forest site, the GPP phenologies generally agreed because both responded to the strong signal associated with minimum temperature. The midsummer MODIS GPP there was generally higher than the ground-based GPP. The differences between the MODIS GPP products and the ground-based GPPs were driven by differences in the timing of FPAR and the magnitude of light use efficiency as well as by differences in other inputs to the MODIS GPP algorithm—daily incident PAR, minimum temperature, and vapor pressure deficit. Ground-based scaling of GPP has the potential to improve the parameterization of light use efficiency in satellite-based GPP monitoring algorithms. 相似文献
76.
用MODIS影像反演环渤海地区的大气水汽含量 总被引:16,自引:1,他引:16
主要介绍通过遥感影像来反演大气水汽的算法,两通道比值法和三通道比值法。并用环渤海地区的MODIS影像对该地区的水汽进行了反演。 相似文献
77.
基于MODIS和GIS的洪灾监测评估系统 总被引:14,自引:0,他引:14
在分析我国遥感技术在洪水监测方面应用的基础上,指出目前洪灾遥感监测在时效性等方面的不足.通过介绍MODIS的特点,以及与NOAA AVHRR的对比,提出建立基于MODIS和GIS的洪灾监测评估系统.利用免费、较高时间分辨率的MODIS数据,运用GIS技术,实现对不同土地利用类型的淹没情况的实时监测,为汛情的动态监测和评估提供迅速、直观、可靠的现状和变化信息. 相似文献
78.
Comparison of land surface emissivity and radiometric temperature derived from MODIS and ASTER sensors 总被引:1,自引:0,他引:1
Frédéric Jacob Franc?ois Petitcolin Éric Vermote Kenta Ogawa 《Remote sensing of environment》2004,90(2):137-152
This study compared surface emissivity and radiometric temperature retrievals derived from data collected with the MODerate resolution Imaging Spectroradiometer (MODIS) and Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) sensors, onboard the NASA's Earth Observation System (EOS)-TERRA satellite. Two study sites were selected: a semi-arid area located in northern Chihuahuan desert, USA, and a Savannah landscape located in central Africa. Atmospheric corrections were performed using the MODTRAN 4 atmospheric radiative transfer code along with atmospheric profiles generated by the National Center for Environmental Predictions (NCEP). Atmospheric radiative properties were derived from MODTRAN 4 calculations according to the sensor swaths, which yielded different strategies from one sensor to the other. The MODIS estimates were then computed using a designed Temperature-Independent Spectral Indices of Emissivity (TISIE) method. The ASTER estimates were derived using the Temperature Emissivity Separation (TES) algorithm. The MODIS and ASTER radiometric temperature retrievals were in good agreement when the atmospheric corrections were similar, with differences lower than 0.9 K. The emissivity estimates were compared for MODIS/ASTER matching bands at 8.5 and 11 μm. It was shown that the retrievals agreed well, with RMSD ranging from 0.005 to 0.015, and biases ranging from −0.01 to 0.005. At 8.5 μm, the ranges of emissivities from both sensors were very similar. At 11 μm, however, the ranges of MODIS values were broader than those of the ASTER estimates. The larger MODIS values were ascribed to the gray body problem of the TES algorithm, whereas the lower MODIS values were not consistent with field references. Finally, we assessed the combined effects of spatial variability and sensor resolution. It was shown that for the study areas we considered, these effects were not critical. 相似文献
79.
Integrative information models for filling/reconstructing hydro-climatic time-series are required for a variety of practical applications. A GIS-based model for a rapid and reliable assessment of monthly time-series of several key hydro-climatic variables at the basin scale, is here developed as plug-in and applied to the entire region of Sicily (Italy). The plug-in, once the desired basin outlet section and time-window are selected, uses appropriate spatial techniques and algorithms to identify its drainage area and estimate the corresponding mean areal rainfall and temperatures time-series. A recent regional regressive rainfall-runoff model is successively applied for the assessment of the runoff time-series. Finally, a consolidated temperature-based method is applied to estimate monthly potential evapotranspiration time-series, while, actual evapotranspiration and soil moisture storage time-series are derived through a classical water balance model. The tool, supported by a preliminarily developed database, includes automatic procedures for data retrieving and processing and a user friendly interface. 相似文献
80.
In recent years,the damage of Apocheima Cinerarius Erschoff in Xinjiang province has seriously threatened the survival and green barrier function of natural Populus euphratica.Due to the large coverage and high tree body of Populus euphratica,traditional monitoring methods are difficult to meet the requirement of rapid monitoring of pest.In this study,the NDVI time series data set of Xiamale forestry in Xinjiang Bachu was reconstructed from the MODIS data from 2014 to the first half of 2017,and the NDVI time series curves were further fitted by three filters.It is found that the S\|G filter can preserve more details of the original curve,and the global fitting can weaken the heterogeneity effectively,so that the vegetation coverage space is better.Through the analysis of the NDVI time series data of the aircraft control area and the comparison with catastrophe point of the non\|flight zone,it is found that the aircraft biological agent means has obvious and continual effects on the controlling of insect pests.proven by the investigation of pest’s population on the ground..The results showed that it was feasible to analyse the insect pests by using the time series of Populus euphratica NDVI. 相似文献