Integration of spatial functional interaction in the extrapolation of ocean surface temperature anomalies due to global warming

The aim of this paper is to derive spatiotemporal extrapolation maps of ocean surface temperature to investigate two global warming effects: On the one hand, the reduction of daily heat fluxes from the sea into the air at the end of the day and during the night, in tropical regions. On the other hand, the strengthening of ocean current flows, due to the increase of ocean surface minimum daily temperature differences between two connected ocean regions. These maps are constructed from the spatial functional time series framework. Specifically, the spatial functional extrapolation of ocean surface temperature from Hawaii Ocean to the Gulf of México reflects an increase of Hawaii Ocean surface temperature in the last 15 years, caused by the reduction of daily heat fluxes from the sea into the air. Furthermore, for the two connected regions of Indian Ocean, and the eastern coast of Australia, the spatial functional extrapolation results derived show more pronounced differences between ocean surface minimum daily temperatures in the year 2003 than in the years 1995–1997. Thus, a strengthening of the flow of the East Australian Current is appreciated.