On the spatio-temporal dynamics of soil moisture at the field scale

In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: On the spatio-temporal dynamics of soil moisture at the field scale s u m m a r y In this paper, we review the state of the art of characterizing and analyzing spatio-temporal dynamics of soil moisture content at the field scale. We discuss measurement techniques that have become available in recent years and that provide unique opportunities to characterize field scale soil moisture variability with high spatial and/or temporal resolution. These include soil moisture sensor networks, hydrogeo-physical measurement techniques, novel remote sensing platforms, and cosmic ray probes. Techniques and methods to analyze soil moisture fields are briefly discussed and include temporal stability analysis, wavelet analysis and empirical orthogonal functions. We revisit local and non-local controls on field scale soil moisture dynamics and discuss approaches to model these dynamics at the field scale. Finally, we address the topic of optimal measurement design and provide an outlook and future research perspectives. Soil moisture is a key state variable in the terrestrial system as it controls the exchange of water and energy between the land surface and the atmosphere. These exchange processes are characterized by a high nonlinearity and complex feedback mechanisms. Soil moisture is highly variable in space and time with characteristic length scales ranging from a few centimeters up to several kilometers and characteristic time scales ranging from minutes up to years. In recent years, soil moisture has been the subject of several review papers. In particular, these review papers focused on different measurement technologies available at the field to catchment scale with a focus on hydrogeophysical methods, sensor technologies and distributed sensor networks (Fares et al., 2013; Robinson et al., 2008a,b), the importance of soil moisture for describing and understanding vadose zone processes (Vereecken et al., 2008a), the role of soil moisture in climate and atmospheric processes (Sene-viratne et al., 2010), and the role that soil properties can play in soil moisture estimation (Zhu et al., 2012). Many studies analyzed spatial variability of soil moisture at a range of scales, including the field scale (Bell et al. Western et al. (2002) reviewed the various scaling techniques that are available to link soil moisture variability across scales and made a …