Towards a fully unstructured ocean model for ice shelf cavity environments: Model development and verification using the Firedrake finite element framework

Numerical studies of ice flow have consistently identified the grounding zone outlet glaciers and streams (the region where starts to float) as crucial for predicting rate grounded loss ocean. Owing extreme environments difficulty access ocean cavities beneath shelves, field observations are rare. Estimates melt rates derived from satellites also difficult make near zones with confidence. Therefore, numerical models important tools investigate these critical remote regions. The relative inflexibility structured grid means, however, that they can struggle resolve processes in irregular cavity geometries zones. To help solve this issue, we present a new nonhydrostatic unstructured mesh model under shelves built using Firedrake finite element framework. We demonstrate our ability simulate full shelf domains community standard ISOMIP+ Ocean0 test case compare results against those obtained popular MITgcm model. Good agreement is found between two models, despite their use different discretisation schemes sensitivity parameterisation resolution. Verification tests based on Method Manufactured Solutions (MMS) show sound second-order accurate. A main driver behind availability an automatically generated adjoint Our first calculations, sensitivities respect inputs idealised domain, promising point address number questions influence vulnerability future.