First observation of the hot spot from space at sub-degree angular resolution using POLDER data

We show that the Polarization and Directionality of the Earth's Reflectances (POLDER)/ADEOS two-dimensional imaging concept permits measurement of the innermost few degrees of the hot spot (the enhancement of land surface reflectance when Sun and view, directions coincide) with an angular resolution of approximately 0.3degrees, The analysis approach assumes that the hotspot characteristics (amplitude. width) are homogeneous over regions of about 50 km in extent. Examples of the hot spot in red and near-infrared bands are shown. The five hot spot examples presented show a variation of less than a factor of two in both amplitude and width, despite sampling a wide variety of land cover including grassland, woodland and dense eucalypt forest. POLDER offers the potential for the first systematic global mapping of hot-spot characteristics, and hence a possible new source of quantitative information on vegetation structure.