Weather and Seasonal Effects on Vertical Reflectivity Profiles: Tower-based Coherent and Correlation Tomographic Observations

Abstract:
Vertical reflectivity profiles can change with time due to non-structural effects such as changes in the water content or phase (liquid/frozen). In this paper, the temporal evolution of vertical L-band reflectivity profiles is studied. Temporally dense tomographic observations were made from the BorealScat radar tower overlooking a boreal forest. Freeze-thaw cycles resulted in large variations in vertical reflectivity profiles, although the deviation in the volume-only centre of mass was insignificant (<2 m) compared to the forest height (25 m). The effects of rainfall on the canopy region of reflectivity profiles were minimal and short lived, whereas large variations were observed for ground-level intensity. In general, normalised L-band volume-only reflectivity profiles were robust to weather and seasonal changes for this boreal forest. Vertical reflectivity profiles derived from correlation tomographic observations were undistorted even in dynamic weather conditions, whereas correlation (repeat-pass) tomographic observation resulted in reduced contrast.