MJO induced diurnal sea surface temperature variations off northwest shelf of Australia observed from Himawari geostationary satellite

High frequency coupling between the tropical upper ocean and atmosphere at diurnal time scales is being recognised as important for the behaviour of large scale climate modes such as Madden Julian Oscillation (MJO). Eastern Indian Ocean warm pool and Northwest shelf of Australia is strongly influenced by the MJO activities. In this study, we use the hourly Himawari-8 geostationary satellite SST data in the Northwest shelf of Australia to understand the modulation of the amplitude of SST diurnal variations with the MJO evolution during the two austral summer seasons of 2015-16 and 2016-17. The high temporal and spatial resolutions of the Himawari-8 SST data were able to capture the temporal and spatial variability of diurnal SST. This study indicates that the diurnal SST variation is a key indicator of and thus plays a fundamental role in the air-sea interactions between MJO and upper-ocean. Our results show that MJO onset (active phase) is preceded by strong diurnal SST variations in MJO suppressed phase. SST diurnal variations are modulated by wind-induced latent heat flux and solar radiation variations. The record El Nino warming event in 2015-16 may have modulated the MJO activities. In addition, we also observe notable spatial variability of diurnal variations of SST in the region, especially during the 2015-16 El Nino event. Citation: Z. Huang, M. Feng, MJO induced diurnal sea surface temperature variations off the northwest shelf of Australia observed from Himawari geostationary satellite, Deep Sea Research Part II: Topical Studies in Oceanography, Volume 183, 2021, 104925, ISSN 0967-0645, https://doi.org/10.1016/j.dsr2.2021.104925