Abstract

An adequate understanding of the ocean-atmosphere interface is important for understanding climate variability on different time scales. Thus, this research focuses on surface heat fuxes over seasonal scales and their changes during el Niño and La Niña along the eastern Pacific coast (10°N-40°S), consistent with oceanographic and meteorological felds. We used a wide range of up-to-date databases, new mean monthly heat air-sea fuxes (NOCS Flux Dataset v2.0) and complementary global databases (SODA reanalysis, SeaWiFS). The results reported here show that of all the fuxes contributing to net heat fux (Q net), net shortwave radiation (Q sw) is the term that warms and is most dominant, and latent heat flux (Q lat) is the term that most contributes to cooling. Considering seasonal variability, Q sw reduction due to cloud cover in the latter half of the year was associated with the presence of the Intertropical Convergence Zone and the stratus cloud deck at 10°N-Eq and Eq-30°S, respectively. The smaller seasonal amplitude south of 30°S was associated with the southern coastal jet that develops along the eastern flank of the low-level circulation over the southeast anticyclonic Pacific. During el Niño and La Niña, the most significant change was observed for Q lat in the first half of the year, between the equator and the Peruvian coast. Q lat tended to cool (warm) during el Niño (La Niña), acting as a negative feedback. Specifically for Q lat, we found that the air-sea specific humidity difference (rather than the wind) played a prominent role in both el Niño - Southern Oscillation phases. The sum of Q net and the shortwave radiation that penetrates through the base of the mixed layer was compared with the sea surface temperature tendency and was discussed.