Effects of including the adjoint sea ice rheology on estimating Arctic Ocean–sea ice state

• DOI: 10.5194/os-19-305-2023
• Publication Date: 2023-03-17T06:38:35Z
• Authors: Guokun Lyu; Armin Koehl; Xinrong Wu; Meng Zhou; Detlef Stammer
• Keywords: Adjoint equation; Sea ice concentration

Abstract. The adjoint assimilation method has been applied to coupled ocean and sea ice models for sensitivity studies Arctic state estimations. However, the accuracy of model is degraded by simplifications model, especially rheologies. As part ongoing developments in estimation systems, we incorporate approximate viscous-plastic dynamics (adjoint-VP) compare it with free-drift (adjoint-FD) through experiments. Using adjoint-VP results a further cost reduction 7.9 % comparison adjoint-FD, noticeable improvements temperature over open water intermediate layers Ocean. Adjoint-VP adjusts input more efficiently than adjoint-FD does involving different retreat processes. For instance, melts up 1.0 m marginal seas from May June overadjusting air (>8 ∘C); reproduces smaller adjustments atmospheric within their prior uncertainty range. These here lay foundation improving Ocean estimations comprehensively adjusting initial conditions, forcings, parameters model.