Introduction to the Special Issue on Airborne Field Campaigns for Soil Moisture

The 52 papers in this special issue make use of airborne and/or ground data to deal with questions such as: 1) the estimation of effective soil temperature and vegetation water content from remote sensing data; 2) the impact of physical parameters such as soil texture, topography, vegetation type. and surface roughness on surface soil moisture retrieval; 3) the transferability of current retrieval equations across scales ranging from tens of kilometers; and 4) issues related to downscaling of low-resolution passive-microwave observations of surface soil moisture.