A dry air atmospheric pressure volume dielectric barrier discharge, produced immediately below a water volume, is employed to produce plasma treated water. Producing treated water with high concentrations of reactive oxygen nitrogen species such as nitrate for use as nitrogen fertilizer is the primary motivation behind this design. A 0D chemistry model is developed and informed by the electrical, geometric and plasma gas temperature characteristics of the device. Modeled ozone and nitrate densities are compared to those measured experimentally in the plasma effluent and treated liquid for a range of gas temperatures.  Good agreement is demonstrated between the ozone densities measured in the effluent; however, the model does not account for the liquid chemistry. A gas temperature based shift from ozone to NO_x producing regimes is observed in both experiment and model, and the reactions responsible for this shift are discussed.