MODIS-derived daily PAR simulation from cloud-free images and its validation

CORC > 地理科学与资源研究所 > 中国科学院地理科学与资源研究所 > 历年回溯文献

	MODIS-derived daily PAR simulation from cloud-free images and its validation
	Chen Liangfu ; Gao Yanhua ; Yang Lei ; Liu Qinhuo ; Gu Xingfa ; Tian Guoliang
	2008
关键词	Aerosols Computer simulation Irradiation Light absorption Mathematical models
英文摘要	In this paper, a MODIS-derived daily PAR (photosynthetically active radiation) simulation model from cloud-free image over land surface has been developed based on Bird and Riordan's model. In this model, the total downwelling spectral surface irradiance is divided into two parts: one is beam irradiance, and another is diffuse irradiance. The attenuation of solar beam irradiance comprises scattering by the gas mixture, absorption by ozone, the gas mixture and water vapor, and scattering and absorption by aerosols. The diffuse irradiance is scattered out of the direct beam and towards the surface. The multiple ground-air interactions have been taken into account in the diffuse irradiance model. The parameters needed in this model are atmospheric water vapor content, aerosol optical thickness and spectral albedo ranging from 400 nm to 700 nm. They are all retrieved from MODIS data. Then, the instantaneous photosynthetically available radiation (IPAR) is integrated by using a weighted sum at each of the visible MODIS wavebands. Finally, a daily PAR is derived by integration of IPAR. In order to validate the MODIS-derived PAR model, we compared the field PAR measurements in 2003 and 2004 against the simulated PAR. The measurements were made at the Qianyanzhou ecological experimental station, Chinese Ecosystem Research Network. A total of 54 days of cloud-free MODIS L1B level images were used for the PAR simulation. Our results show that the simulated PAR is consistent with field measurements, where the correlation coefficient of linear regression between calculated PAR and measured PAR is 0.93396. However, there were some uncertainties in the comparison of 1 km pixel PAR with the tower flux stand measurement. © 2007 Elsevier Ltd. All rights reserved.
出处	Solar Energy
卷	82 期:6 页:528-534
收录类别	EI
语种	英语
内容类型	EI期刊论文
源URL	[http://ir.igsnrr.ac.cn/handle/311030/25001]
专题	地理科学与资源研究所_历年回溯文献
推荐引用方式 GB/T 7714	Chen Liangfu,Gao Yanhua,Yang Lei,et al. MODIS-derived daily PAR simulation from cloud-free images and its validation. 2008.