RT Codes

Official code comparison Web site of the MODIS atmospheric correction group


This is an official code comparison site of the MODIS atmospheric correction group at the University of Maryland. Our group is responsible for the development, further improvement, and validation of a vector version of the 6S radiative transfer (RT) code used for atmospheric correction of MODIS data. We are also in charge of organizing and controlling a joint code comparison project devoted to the comparison of several vector/scalar RT codes, which we perform in collaboration with the NASA Goddard Space Flight Center.

Latest updates on the 6S status

1. A β-version of the vector 6S code (6SV1.0B) was released in May, 2005. A lastest version (6SV2.1), recently released in June 2015, is now available. Both of these two versions can be downloaded here. The Web interface , using the first vector β-version of the code (6SV1.0B) can help the inexperienced user learn how to use the code.

2.The validation study of the vector 6S code has been completed. The results are summarized in few publications which can be downloaded here.

Latest updates on the code comparison project

1. The results of the project were partially presented at the AEROCENTER seminar on October 2nd, 2007. The participating codes were estimated on the basis of four major characteristics: versatility, accuracy, user-friendliness, and speed (Download the presentation).

2. The project has been completed. The results are presented on this site and summarized in the following publication: S. Y. Kotchenova, E. F. Vermote, R. Levy, and A. Lyapustin. Radiative transfer codes for atmospheric correction and aerosol retrieval: intercomparison study, Applied Optics, Vol. 47, No. 13, p. 2215-2226, 2008.

Note: The 'Effects of polarization' section also describes the impact of differences between simulations of the codes on aerosol optical thickness and surface reflectance retrievals.