Drylands cover about 41% of the Earth’s land surface and are defined by low mean annual precipitation amounts compared to potential evaporation. They show high variability in both rainfall amounts and intensities and the occurrence of cyclic and prolonged periods of drought. Drylands support humans through diverse land use systems, provide ecosystem services of global importance and harbor exceptional levels of biodiversity. Remote sensing applications in such environments are hampered by complex and often heterogeneous landscape mosaics, a comparably low signal level in combination with high inter-and intra-annual variations, and highly variable availability of optical data reflecting dry and wet seasons. On top of this, seasonal fire regimes add additional challenges in interpreting the signal. At the same time, there is an unprecedented number of sensor systems from the optical and radar domain. These cover a wide range of spatial and spectral resolutions, revisit rates, and in combination with the availability of long-term archives offer unique potential in addressing these challenges and adapting some of the well-developed applications in forest ecosystems to dryland systems.
This Special Issue therefore aims at providing a platform for the most recent advances in suitable indicators, appropriate time series analysis techniques and strategies to integrate these into assessment and monitoring concepts, where case studies should demonstrate their potential for transferability. We explicitly encourage submissions that showcase the potential of novel sensor systems for advanced assessments and how these may be interfaced with existing archives for long-term and large-area monitoring.
Dr. Achim Röder
Dr. Marion Stellmes