Atmospheric Lengthscales for Global VSWIR Imaging Spectroscopy

Future global Visible Shortwave Infrared Imaging Spectrometers, such as the Surface Biology and Geology (SBG) mission, will regularly cover the Earth's entire terrestrial land area. These missions need high fidelity atmospheric correction to produce consistent maps of terrestrial and aquatic ecosystem traits. However, estimation of surface reflectance and atmospheric state is computationally challenging, and the terabyte data volumes of global missions will exceed available processing capacity. This article describes how missions can overcome this bottleneck using the spatial continuity of atmospheric fields. Contemporary imaging spectrometers oversample atmospheric spatial variability, so it is not necessary to invert every pixel. Spatially sparse solutions can train local linear emulators that provide fast, exact inversions in their vicinity. We find that estimating the atmosphere at 200 m scales can outperform traditional atmospheric correction, improving speed by one to two orders of magnitude with no measurable penalty to accuracy. We validate performance with an airborne field campaign, showing reflectance accuracies with RMSE of 1.1% or better compared to ground measurements of diverse targets. These errors are statistically consistent with retrieval uncertainty budgets. Local emulators can close the efficiency gap and make rigorous model inversion algorithms feasible for global missions such as SBG.

Achieving population dispersal through tailor-made community planning: an Israeli experiment in the Galilee region

The author describes a program designed to encourage population dispersal that was carried out in the central Galilee region of Israel during the 1980s. The program involved setting up 52 small communities with the appropriate infrastructures to attract young, well-educated settlers. "The plan succeeded in attracting the desired type of population...to the region, and the newcomers viewed the new communities as their permanent homes. Based on this experience and on the analysis of relevant literature, a development strategy of tailor-made community planning is hereby recommended for future projects. It is especially appropriate in the context of developed countries with a slow to zero population growth and with spreading social norms of the postindustrial society."