Metrics for Intercomparison of Remapping Algorithms (MIRA) protocol applied to Earth system models

Abstract. Strongly coupled nonlinear phenomena such as those described by Earth system models (ESMs) are composed of multiple component with independent mesh topologies and scalable numerical solvers. A common operation in ESMs is to remap or interpolate solution fields defined on their computational another a different combinatorial structure decomposition, e.g., from the atmosphere ocean, during temporal integration system. Several remapping schemes currently use available for ESMs. However, unified approach compare properties these has not been attempted previously. We present rigorous methodology evaluation intercomparison methods through an independently implemented suite metrics that measure ability method adhere constraints grid independence, monotonicity, global conservation, local extrema feature preservation. comprehensive set evaluations conducted based progression scalar idealized smooth more general climate data strong discontinuities strict bounds. examine four algorithms distinct design approaches, namely ESMF Regrid (Hill et al., 2004), TempestRemap (Ullrich Taylor, 2015), generalized moving least squares (GMLS) (Trask Kuberry, 2020) post-processing filters, WLS-ENOR (Li 2020). By repeated iterative application high-order test fields, we verify accuracy each scheme terms observed convergence order determine bounded error propagation using challenging, realistic field both uniform regionally refined cases. In addition retaining under conditions, also demonstrate robust performance when dealing non-smooth data. There failure maintain monotonicity traditional L2-minimization approaches used TempestRemap, contrast stable recovery filters meshless GMLS hybrid mesh-based schemes. Local preservation analysis indicates perform better than low-order dissipative all The behavior remappers remains consistent applied meshes, indicating mesh-invariant implementations. MIRA protocol proposed this paper detailed comparison new schemes, WLS-ENOR, competitive compared standard conservative minimization requiring computation intersections. work presented provides foundation can be extended include complex definitions, topologies, spectral element discretizations, thereby allowing complete production-ready packages.