L-band tomographic monitoring of temperate forests with TangoSAT – Potentials, challenges and synergies

Abstract

Forest vertical structure is a key variable for assessing biodiversity, structural degradation and/or regeneration, and for the development of accurate biomass estimators. Moreover, the knowledge of forest structure changes is important to determine the type and the intensity of forest disturbance as well as the seasonal and annual forest cycle variation. In this framework, the next generation of low-frequency spaceborne SAR configurations will play a crucial role in forest structure monitoring as they will provide the unique ability to image large areas at high spatial and temporal resolution. More importantly, active-passive SAR constellations like the TangoSAT mission will allow to measure bistatic interferometric coherences repeatedly without the disturbing effect of temporal decorrelation on a global scale. This enhanced observation scenario motivates the exploration of the information content of multi-baseline interferometric measurements for the retrieval of physical forest structure parameters by means of tomographic techniques. With this objective in mind, in this work real data results will be presented focusing on the temperate forest of Traunstein (Germany). By processing multibaseline-multitemporal airborne data, a comparison between L-band and P-band tomographic profiles will be carried out to assess (1) their physical information content and (2) their synergies and complementarities. For this purpose, ground measurements will be extensively used. Moreover, considering L-band acquisitions, changes of the profiles induced by environmental (e.g. due to moisture change) and seasonal effects will be quantified. Finally, a first investigation of the impact of the temporal variability of such effects on the profile reconstruction will be presented.