Rapidly shrinking Arctic sea ice has had significant impacts on the Arctic Ocean and many outer Arctic regions. It is therefore urgently needed to reliably estimate Arctic sea-ice thickness (SIT) by combined use of available observation and numerical modeling. Here, for the first time, we assimilate the latest CryoSat-2 summer SIT data into a coupled ice-ocean model. In particular, an Incremental Analysis Update scheme is implemented to overcome the discontinuity brought by assimilating biweekly SIT and daily sea ice concentration data. Along with an improvement in sea ice volume, our SIT estimates have smaller errors than that without SIT assimilation in areas where the sea ice is roughest and experiences strong deformation, e.g., around the Fram Strait and Greenland. This study suggests that the newly-developed CryoSat-2 SIT product, when assimilated properly with our approach, has great potential for Arctic sea ice simulation and prediction.

This article is composed of three independent commentaries of how Integrated, Coordinated, Open, and Networked (ICON), as well as Findable, Accessible, Interoperable, and Reusable (FAIR; under the umbrella of I from ICON), principles are currently embedded in ocean sciences, and what are the opportunities and challenges by adopting them. Each commentary focuses on a different perspective as follows: (i) field sampling and experimentation to remote-sensing and autonomous observations (Section 1); (ii) global collaboration, technology transfer and application, reproducibility, and data sharing and infrastructure (Section 2); (iii) increasing diversity and broadening participation in ocean sciences (Section 3). Overall, there is a consensus that ocean sciences is well-advanced in adopting many of the ICON-FAIR principles regarding (i) and (ii), although there are still plenty of opportunities to develop further by, for instance, making broader use of data-of-opportunity and citizen science, improving efforts towards standardized data organization and avoiding data fragmentation, and increasing training activities to implement good practices. On the other hand, fostering diversity and broadening participation in ocean sciences is still in its infancy. Actions are needed to overcome under-representation of women and other marginalized groups, create opportunities for early-career scientists, and build bridges to support scientists from low-income countries. We recognize that adopting ICON-FAIR principles come with high costs and efforts, but it has strong potential to develop ocean sciences in many aspects.