Analysis of the topographic effect on the radiometric correction of MERIS images
Keywords:DEM, MERIS, topographic correction, radiometric correction, O2A-absorption band
Topography alters the vertical structure of the atmosphere and, therefore, its radiative properties regarding the reflection and transmission of the solar radiation. Also it modifies the conditions of illumination of terrain, with remarkable influence in the remote sensing measures of the terrestrial surface in the optical spectrum. In this work we have applied two models of atmospheric and radiometric correction on an ENVISAT/MERIS image, considering the topography, to analyse the importance of such effects. For this, we have exploited the recent rise of Digital Models of Elevation (MDE) sufficiently detailed and precise, available to a global scale, that open new prospects for the topographical corrections of remote sensing data. The results show the adjustment of the conjoint correction model (atmospheric and topographical) in the considered case, improving comparison of spectral signatures of similar surfaces independently of the elevation or the conditions of illumination, compensating the relative variations caused by the topography in the reflectivity measured by sensors. Although the remote sensing of the terrestrial surface has tended traditionally to avoid the bands of atmospheric absorption, a peculiarity that presents the ENVISAT/MERIS images is the availability of a band (O2A) of absorption of the oxygen, located in the 761.5 nm. This band is used mainly for atmospheric corrections (estimate of the surface’s pressure, elevation of clouds, aerosols effects, etc.). But also it has been employed recently to determine the fluorescence of the vegetation, consequently this band of absorption has received remarkable attention in the last years. Considering that this absorption of the oxygen is strongly affected for topography, the determination of information on the terrestrial surface from this absorption of the oxygen requires a very precise correction of the topographical effects. Therefore in this work we analyse in particular the effect of the peak of reflectivity at 761.5 nm originated by an inappropriate correction of the topography and we study the existent relationship between the local atmospheric pressure and the depth band of absorption of the oxygen in this wavelength.
Bernstein, L.S., Adler-Golden, S.M., Sundberg, R.L., Levine, R.Y., Perkins, T.C., Berk, A., Ratkowski, A.J., Felde, G., Hoke, M.L., 2005. A new method for atmospheric correction and aerosol optical property retrieval for VIS-SWIR multi- and hyperspectral imaging sensors: QUAC (quick atmospheric correction). En: Proceedings of International Geosciences and Remote Sensing Symposium. Seoul, Korea, 25-29 Julio. pp 3549- 3552.
Berk, A., Anderson, G.P., Bernstein, L.S., Acharya, P.K., Dothe, H., Matthew, M.W., Adler-Golden, S.M., Chetwynd, J.H., Richtsmeier, S.C., Pukall, B., Allred, C.L., Jeong, L.S., Hoke, M.L. 1999. MODTRAN4
radiative transfer modeling for atmospheric correction. En: Proceedings of SPIE Optical Spectroscopic Techniques and Instrumentation for Atmospheric and Space Research III, Denver, Co, USA, 18 July, 1999
Felicísimo, A. M., 1994. Modelos digitales del terreno. Introducción y aplicaciones en las ciencias ambientales. Oviedo: Pentalfa Ediciones.
Guanter, L., González-Sanpedro, M.C., Moreno, J. 2007.A method for the atmospheric correction of ENVISAT/MERIS data over land targets. International Journal of Remote Sensing, 28(3-4): 709-728. http://dx.doi.org/10.1080/01431160600815525
Moreno, J.F., 1996. Radiometric Corrections of Visible/Infrared Satellite Data Over Terrestrial Environments: Angular, Atmospheric and Topographic Effects. En: Proceedings of International Geosciences and Remote Sensing Symposium. Lincoln, EE.UU., 27-31 Mayo. pp 1823-1825.
Sandmeier, S., Itten, K. 1997. A physically-based model to correct atmospheric and illumination effects in optical satellite data of rugged terrain. IEEE Transactions on Geosciences and Remote Sensing, 35(3): 708-717.http://dx.doi.org/10.1109/36.581991
Wood, J. 1996. The Geomorphological Characterisation of Digital Elevation Models. Ph.D. Thesis, Department of Geography, University of Leicester, Leicester, UK.
Zakšek, K., Oštir, K., Kokalj, Ž. 2011. Sky-View Factor as a Relief Visualization Technique. Remote Sensing 3(2): 398-415. http://dx.doi.org/10.3390/rs3020398
This journal is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International