Transporting CRM Variance in a Multiscale Modelling Framework

Abstract. An unphysical checkerboard pattern has recently been identified in E3SM-MMF that is hypothesized to be associated with the inability of the large-scale dynamics to transport fluctuations within the embedded CRM on the global grid. To address this issue, a method is presented to facilitate large-scale transport of CRM variance in E3SM-MMF. Simulation results show that the method is effective at reducing the occurrence of unphysical checkerboard patterns on a range of time scales, from days to years. This result is confirmed both subjectively through visual inspection and quantitatively with a previously developed pattern categorization technique. The CRM variance transport does not significantly alter the model climate, although is does tend to reduce temporal variance on fields associated with convection on the global grid.