This dataset includes the following measurements made over a xeric tall grass prairie in the southwest portion of Rocky Flats National Wildlife Refuge in 2011 and 2012: 1) half hourly eddy covariance measurements of latent heat flux (evapotranspiration) and fluxes of carbon dioxide and sensible heat, and friction velocity (U star) 2) half hour averages of solar and net radiation; photosynthetically active radiation; air temperature and humidity; soil temperature, moisture, and heat flux; wind speed and direction; and half hour sums of precipitation. 3) approximately weekly measurements of vegetation including leaf area index, height of vegetation, dry and wet weights