Fig. 1. Description of the POPLEX field campaign. This 3-D representation of the study area with a translucent QuikSCAT-DSM overlay shows four satellites and five monitoring stations, representing the many others used for POPLEX. Air (A), groundwater (G), and river (R) discharge stations are marked with map pins. The graphs show examples of groundwater quality, air quality, and river discharge. The black path represents the POPLEX itinerary. Urban areas, field sites, monitoring instruments, and activities are also depicted in the insets. Coordinates refer to GCS WGS 1984. Credit: NASA Jet Propulsion Lab and POPLEX Team