TC Induced SST Anomalies in the Eastern Pacific

Tropical cyclones (TC) are widely known to cool sea surface temperatures (SST) due to enhanced vertical mixing and surface fluxes. However, this process is reversed in the eastern tropical Pacific (ETP), where the cooling is replaced by an anomalous warming. Through the use of satellite imagery and optimally interpolated observational products, we show that the TC-induced warming in the ETP is due to enhanced radiative forcing associated with decreased cloudiness following storms. These enhanced fluxes are strong enough to reverse the TC-induced cooling effect and produce significant surface warming in the region. The anomalous warming feature occurs only in the ETP and is due to the region's unique vertical cloud distribution. We find that TCs tend to destroy low lying clouds in this region, leading to clear sky conditions after storm passage and thus increased shortwave radiative forcing and warmer SSTs. These results indicate important climate connections between tropical cyclones and background cloudiness which can potentially influence temperature variability, upper-ocean heat budgets, ocean-atmosphere fluxes, and subsequent TCs affecting the same regions.