Tandem-L Forest Parameter Performance Analysis
Francesco De Zan(1), Seung-Kuk Lee(1) and Kostas Papathanassiou(1)
(1) DLR - German Aerospace Center, P.O. Box 1116, D-82230 Wessling, Germany
Tandem-L is a proposal for an innovative interferometric radar mission that enables the systematic monitoring of dynamic processes on the Earth surface. Important application areas are global forest structure and forest vegetation monitoring, measurement of Earth deformation due to tectonic processes, observation of 3-D structure changes in ice, and the monitoring of ocean surface currents. The mission goals will be achieved through the deployment of two satellite platforms with quad-polarimetric L-band SARs that will be operated jointly for five years.
In this paper, we focus on the mission goals concerning (dynamic) forest parameter forest mapping and characterization. i.e. on the estimation of forest height, forest vertical structure and forest biomass as well as on the characterization of their individual change. For this, the polarimetric and single-pass interferometric capabilities of the system are primarily aimed at estimating forest height and vertical structure, through the Pol-InSAR analysis and (quasi-) tomographic techniques. In order to organize the allocation of resources (time, fuel, data volume) to the different mission objectives, and to design an optimized mission scenario, we derive performance models for each different application that depend on the individual system and mission parameter we desire to optimize.
We consider model-based approaches to forest height and structure retrieval which can lead to the discrimination between basic forest types, depending on the presence or absence of certain layers. We suggest that this discrimination will support the above ground biomass estimation together with other allometric relations. The performance models are developed and optimized with respect to the Tandem-L observation scenario and thus based on the combination of a limited number of (single and repeat-pass) spatial baselines expected to be available for each point on the earth. We introduce the individual performance models and use them to identify the key system and mission parameters that impact the performance of forest parameter estimation by means of Tandem-L. Then, based on the product requirements we derive a set of first system and mission requirements.