This data package contains metadata for, and links to, 30-minute mass and energy flux data collected at an eddy covariance tower in the Tromble Weir Watershed area of the Jornada Basin in southern New Mexico, USA. These data are used to quantify the water and energy balances in a small experimental watershed, including observational studies to calculate groundwater recharge as a water balance residual, to build relations between soil moisture state and ET flux, and to quantify land-atmosphere interactions and improve our understanding of the eddy covariance method. Additionally, they have been used in modeling studies as a validation of model performance. The .csv files included in this package list and describe the data entities and variables present in data files archived at the AmeriFlux data repository (site US-Jo2; http://ameriflux.lbl.gov/sites/siteinfo/US-Jo2). The data at AmeriFlux include the 30-minute mass and energy fluxes calculated from 20 Hz data collected at the Tromble Weir Watershed tower. Instrument descriptions and detailed procedures are found in the references listed in the Methods section of this EDI package. This is an ongoing dataset that will be updated annually.