Abstract. Parameters in sea ice-ocean coupled models greatly affect the simulated ocean and ice evolution, are normally tunned to bring model state close observations. Using an adjoint method, spatiotemporally varying parameters of Arctic optimized simultaneously with initial condition atmospheric forcing by assimilating satellite in-situ The assimilation results show that joint parameter estimation (SPE) substantially improves concentration simulation. Particularly October when surface...

Abstract The adjoint method is used to calibrate the medium complexity climate model “Planet Simulator” through parameter estimation. Identical twin experiments demonstrate that this can retrieve default values of control parameters when using a long assimilation window order 2 months. Chaos synchronization nudging, required overcome limits in temporal method, employed successfully reach length. When assimilating ERA‐Interim reanalysis data, observations air temperature and radiative fluxes...

Abstract. Two high-resolution model simulations are used to investigate the spatiotemporal variability of Arctic Ocean sea level. The reveal barotropic level at periods < 30 d, which is strongly captured by bottom pressure observations. seasonal driven volume exchanges with Pacific and Atlantic oceans redistribution water wind. Halosteric effects due river runoff evaporation minus precipitation ice melting/formation also contribute in marginal seas extent regions. In central Ocean,...

Abstract Arctic Ocean Observing System Simulation Experiments (OSSEs) were performed with a pan‐Arctic coupled ocean–sea ice data assimilation system to assess the impacts of assimilating available observations on state. To this end, adjoint method 3‐year window was used assimilate synthetic sampled from 4 km model simulation at spatio‐temporal distribution existing observing system. After assimilation, sea state, including concentration (SIC), thickness (SIT), and volume (SIV),...

Abstract We present an Arctic ocean–sea ice reanalysis covering the period 2007–2016 based on adjoint approach of Estimating Circulation and Climate Ocean (ECCO) consortium. The spatiotemporal variation sea surface temperature (SST), concentration (SIC), thickness (SIT) is substantially improved after assimilation ocean observations. By assimilating additional World Atlas 2018 (WOA18) hydrographic data, freshwater content Canadian Basin becomes closer to observations translates into changes...

Abstract. Two high-resolution model simulations are used to investigate the spatio-temporal variability of Arctic Ocean sea level. The reveal barotropic level at periods < 30 days, which is strongly captured by bottom pressure observations. seasonal driven volume ex-changes with Pacific and Atlantic Oceans redistribution water wind. Halosteric effects due river runoff evaporation minus precipitation (EmPmR), ice melting/formation also contribute in marginal seas extent regions. In central...

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,...

<p>The need for reliable climate predictions is growing in demand various socio-economic sectors. The predictability studies though show that Earth System Models (ESMs) can predict important variables, the suffer from model errors and initialization shocks limit predictability. magnitude of this effect difficult to quantify unless one could perform experiments dynamically- model-consistent settings contrast against each other sources shocks. This idea our study, which concerns...

<p>As part of the ongoing development a data assimilation system for reconstructing Arctic ocean-sea ice state, we incorporated an adjoint sea rheology, which was approximated by free drift assumption due to stability problem, into model coupled model. The sensitivity experiments show that internal stress effect, represented induced remarkable differences in sensitivities and wind central Ocean. In contrast, is mostly marginal zone. reveal including rheology helps extract...

Abstract. The adjoint technique has been applied to the coupled ocean and sea ice models for sensitivity studies Arctic state estimation. However, accuracy of model is degraded by simplifications on model, especially rheology. As part ongoing developments estimation system, we incorporate stabilize viscous-plastic dynamics (adjoint-VP) compare it with a free drift (adjoint-FD) through assimilation experiments. Using adjoint-VP resulted in further cost reduction 7.9 % comparison adjoint-FD...