Link between Seashore Water Temperature and Open Ocean State in Peru

Abstract

The link between the coastal ocean and the open sea varies greatly by region. This factor must be elucidated to consider climate projections for a particular coastal region. This study examines this link between coastal areas in Peru and open seas. Water temperature loggers were installed at six sites along the Peruvian coast between 2017 and 2020. The obtained data and that from the EN4 dataset of the open ocean were compared. The coastal water temperature changes in Peru correlates well with the open ocean sea surface temperature in terms of monthly mean anomalies. The correlation coefficient values range from 0.80 to 0.92 with a > 99% confidence level except for one observation point (0.26). This suggests a global ocean observation system underlying EN4 can directly contribute to a reliable climate (water temperature) prediction of coastal areas in Peru. On shorter timescales, the logger-derived temperature changes show spectral peaks at 80 and 120 days north of 5°S, suggesting the coastal monitoring can capture the sub-seasonal dynamical aspects of equatorial Kelvin waves. In contrast, clear peaks are not detected south of 5ºS, implying that a practical leak of equatorial wave energy into off-equatorial regions is not anticipated along Peruvian coast on this time scale.