Authors: Momchil Molnar (APS, LASP, University of Colorado, Boulder/NSO), Kevin Reardon (University of Colorado, Boulder/NSO), Steven Cranmer (APS, LASP,University of Colorado, Boulder), Adam Kowalski (APS, LASP,University of Colorado, Boulder; NSO)

We present observational constraints on the chromospheric wave heating from spectral chromospheric observations with the IRIS spacecraft. The data from the IRIS observatory covers diagnostics sampling the solar atmosphere from the photosphere through the high chromosphere to the corona. Based on sit-and-stare UV spectral observations of the Mg II h&k spectral window we compute the velocity and intensity fluctuations in the chromosphere and find them to agree with previous observations in the optical and millimeter. We compare these observations with synthetic data from modern rMHD (Bifrost) models of the solar chromosphere and we find the agreement satisfactory. However, when we examine the amount of wave energy flux in the simulations, we find that it is not as well correlated with the observed velocity or intensity oscillations as expected. This has profound implications for inferring wave fluxes and sheds doubt on previous work, specifically 1D static models.