Observations from spaceborne radar contain considerable information about vegetation dynamics.The ability to extract this information could lead to improved soil moisture retrievals and the increased capacity to monitor vegetation phenology and water stress using radar data.The purpose of this review paper is to provide an overview of the current state of knowledge with respect to backscatter from vegetated (agricultural) landscapes and to identify opportunities and challenges in this domain.Much of our understanding of vegetation backscatter from agricultural canopies stems from SAR studies to perform field-scale classification and monitoring.Hence, SAR applications, theory, and applications are considered here too.An overview will be provided of the knowledge generated from ground-based and airborne experimental campaigns that contributed to the development of crop classification, crop monitoring, and soil moisture monitoring applications.A description of the current vegetation modeling approaches will be given.A review of current applications of spaceborne radar will be used to illustrate the current state of the art in terms of data utilization.Finally, emerging applications, opportunities and challenges will be identified and discussed.Improved representation of vegetation phenology and water dynamics will be identified as essential to improve soil moisture retrievals, crop monitoring, and for the development of emerging drought/water stress applications.

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Tandem-L is a highly innovative SAR satellite mission for the global observation of dynamic processes on the Earth's surface with hitherto unknown quality and resolution. Thanks to its novel imaging techniques and its unprecedented acquisition capacity, Tandem-L will deliver urgently needed information for the solution of pressing scientific questions in the areas of the biosphere, geosphere, cryosphere and hydrosphere. The feasibility of Tandem-L has been analyzed and confirmed in the scope of a phase A study, which has been conducted in close cooperation between the German Aerospace Center (DLR) and the German space industry. This paper provides an overview of the Tandem-L mission concept and summarizes the actual development status.

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The German Tandem-L mission is devoted to provide an overall observation of the dynamic processes within the Eart system at different spatial and temporal scales. Among the mission objectives, the measurement of the 3-D fores structure by means of multi-pass coherence SAR tomography (TomoSAR) has particular relevance. Up to now, th potential of TomoSAR for the characterization of the forest volume has been proved with airborne data, but Tandem-will allow for the first time to map the vertical forest structure and monitor seasonal and annual variations globall with a high spatial resolution. Recently, a performance model for the characterization of the structure information o multibaseline (MB) data stacks has been presented, and the primarily objective of this paper is to examine in dept such model for global performance analysis and investigate the required acquisition trade-offs in the framework of th Tandem-L mission design and acquisition plan.

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ALOS-Next/Tandem-L is a proposal for a highly innovative L-band SAR satellite mission for the global observation of dynamic processes on the Earth's surface with hitherto unparalleled quality and resolution. It is based on a collaboration between DLR and JAXA which started with a pre-phase A study in 2013 and is currently undergoing a phase A study. Thanks to the novel imaging techniques and the vast recording capacity with up to 8 Tbytes/day, it will provide vital information for solving pressing scientific questions in the biosphere, geosphere, cryosphere, and hydrosphere. By this, the new L-band SAR mission will make an essential contribution for a better understanding of the Earth system and its dynamics. ALOS-Next/Tandem-L will, moreover, open new opportunities for risk analysis, disaster management and environmental monitoring by employing especially designed acquisition modes and techniques in combination with a reconfigurable tandem satellite configuration and an L-band SAR instrument with advanced digital beamforming techniques.

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In this paper the science requirements for the mapping of dynamic processes on the Earth surfaces is presented. From the science requirements and the need of a regular and continuous global surface cover for most of the applications a dedicated mission concept has been developed. The presented results are a summary of pre-phase A mission study that is performed in a bilateral cooperation between the Japan Aerospace Exploration Agency (JAXA) and the German Aerospace Center (DLR). Tandem-L is an innovative mission proposal that will provide a unique, world-wide database for a better understanding of the Earth system dynamics in important research and societal relevant fields, as well as enabling a multitude of innovative applications.

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This paper provides an overview of the BIOMASS Mission End-to-End simulator (BEES) and of the mission performance analysis performed with it. The end-to-end performance, in terms of biomass estimates error, is close to the 20% error goal set for the mission. The main sources of errors are temporal decorrelation and the limited available bandwidth, while system induced errors have a negligible impact on the final performance.@en

This paper discusses the implementation of an end-to-end simulator for the BIOMASS mission. An overview of the system architecture is provided along with a functional description of the modules that comprise the simulator.@en

SIGNAL is an innovative earth exploration mission proposal with the main objective to estimate accurately and repeatedly topography and topographic changes associated with mass change or other dynamic effects on glaciers, ice caps and polar ice sheets. Elevation measurements are complemented with glacier velocity measurements, providing valuable additional information for a better understanding of the hydrology of glacierized basins and of the Arctic and Antarctic water cycle. SIGNAL is capable of monitoring all critical regions with a high spatial resolution and an adequate revisit time. This paper gives an overview about the actual mission design status and provides a brief description of the topography (DEM - digital elevation map) self-calibration strategy and the estimated global interferometric performance.@en

Tandem-L is a proposal for an innovative interferometric and polarimetric radar mission that enables the systematic monitoring of dynamic processes on the Earth surface. Important mission objectives are global forest height and bio-mass inventories, large scale measurements of millimetric displacements due to tectonic shifts, and systematic observations of glacier movements. The innovative mission concept and the high data acquisition capacity of Tandem-L provide a unique data source to observe, analyze and quantify the dynamics of a wide range of mutually interacting processes in the bio-, litho-, hydro- and cryosphere. By this, Tandem-L will be an essential step to advance our understanding of the Earth system and its intricate dynamics.@en