Ocean-Atmosphere Interrelation of Bjerknes Feedback Loop Associated with Indian Ocean Dipole Retrieved from Altimeter Radar and Microwave Radiometer of Satellite Altimetry

Abstract

In the past few decades, satellite altimetry has surpassed tremendous achievements in examining the mesoscale of ocean dynamics. Recently, new potential of the satellite in observing the variability of climate phenomena through atmospheric medium been unlocked. As it has been ascertained that satellite altimetry not only outstanding in monitoring ocean dynamic, but also in observing atmospheric variability, we intuitively propose a hypothesis that satellite altimetry is reliable in monitoring Bjerknes feedback; a feedback loop involving interaction between atmosphere and oceans. Thus, the aim of this study is to determine the capability of satellite altimetry in observing Bjerknes feedback through Precipitable Water Vapour (PWV) and Sea Level Anomaly (SLA) during the anomalous climate mode of Indian Ocean Dipole (IOD). The results signify the convincing arguments as both PWV and SLA indexes have high correlation with Dipole Mode Index (DMI), particularly in the west region of Indian Ocean; 0.67 and 0.62, respectively. The correlation of PWV and SLA indexes are also significantly high; 0.73 and 0.69 in west and east region, respectively. The Principal Component Analysis (PCA) results are also convincing as the spatial pattern of primary (PC1) and secondary (PC2) components of both PWV and SLA are associated with positive and negative IOD, respectively. The temporal pattern of PC1 for PWV and SLA have relatively high correlation with positive IOD. The substantially high temporal correlation (0.81) between PWV and SLA PC1 has reinforce the confidence in the capability of satellite altimetry in observing the Bjerknes feedback.