The surface heat fluxes along the eastern Pacific coast from 10°N to 40°S

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 fluxes over seasonal scales and their changes during El Nino and La Nina along the eastern Pacific coast (10 degrees N-40 degrees S), consistent with oceanographic and meteorological fields. We used a wide range of up-to-date databases, new mean monthly heat air-sea fluxes (NOCS Flux Dataset v2.0) and complementary global databases (SODA reanalysis, SeaWiFS). The results reported here show that of all the fluxes contributing to net heat flux (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 degrees N-Eq and Eq-30 degrees S, respectively. The smaller seasonal amplitude south of 30 degrees 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 Nino and La Nina, 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 Nino (La Nina), 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 Nino - 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.