Improving the usability of the MISR L1B2 Georectified Radiance Product (2000–present) in land surface applications

Abstract

Abstract. The Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA s Terra platform has been acquiring global measurements of the spectro-directional reflectance of the Earth since 24 February 2000 and is still operational as of this writing. The primary radiometric data product generated by this instrument is known as the Level 1B2 Georectified Radiance Product (GRP): it contains the 36 radiometric measurements acquired by the instrument s 9 cameras, each observing the planet in 4 spectral bands. The product version described here is projected on a digital elevation model and is available from the NASA Langley Atmospheric Science Data Center (ASDC) ( https://doi.org/10.5067/Terra/MISR/MI1B2T_L1.003 (Jovanovic et al., 1999). The MISR instrument is highly reliable. Nevertheless, its on-board computer occasionally becomes overwhelmed by the amount of raw observations coming from the cameras focal planes, especially when switching into or out of Local Mode acquisitions that are often requested in conjunction with field campaigns. Whenever this occurs, one or more lines of data are dropped while the computer resets and readies itself for accepting new data. Although this type of data loss is minuscule compared to the total amount of measurements acquired, and is marginal for atmospheric studies dealing with large areas and long periods of time, this outcome can be crippling for land surface studies that focus on the detailed analysis of particular scenes at specific times. This paper describes the problem, reports on the prevalence of missing data, proposes a practical solution to optimally estimate the values of the missing data and provides evidence of the performance of the algorithm through specific examples in South Africa. The software to process MISR L1B2 GRP data products as described here is openly available to the community from the GitHub web site https://github.com/mmverstraete or https://doi.org/10.5281/zenodo.3519989 .