Seasonal and Interannual Variability of the Indo-Pacific Warm Pool and its Associated Climate Factors Based on Remote Sensing

Zi Yin,Shuang Long,Qing Dong,Fanping Kong,Dan Cao

doi:10.3390/rs12071062

Abstract

With satellite observed Sea Surface Temperature (SST) accumulated for multiple decades, multi-time scale variabilities of the Indo-Pacific Warm Pool are examined and contrasted in this study by separating it into the Indian Ocean sector and the Pacific Ocean sector. Surface size, zonal center, meridional center, maximum SST and mean SST as the practical warm pool properties are chosen to investigate the warm pool variations for the period 1982–2018. On the seasonal time scale, the oscillation of the Indian Warm Pool is found much more vigorous than the Pacific Warm Pool on size and intensity, yet the interannual variabilities of the Indian Warm Pool and the Pacific Warm Pool are comparable. The Indian Warm Pool has weak interannual variations (3–5 years) and the Pacific Warm Pool has mighty interdecadal variations. The size, zonal movement and mean SST of the Indian Ocean Warm Pool (IW) are more accurate to depict the seasonal variability, and for the Pacific Ocean Warm Pool (PW), the size, zonal and meridional movements and maximum SST are more suitable. On the interannual scale, except for the meridional movements, all the other properties of the same basin have similar interannual variation signals. Following the correlation analysis, it turns out that the Indian Ocean basin-wide index (IOBW) is the most important contributor to the variabilities of both sectors. Lead-lag correlation results show that variation of the Pacific Ocean Warm Pool leads the IOBW and variation of the Indian Ocean Warm Pool is synchronous with the IOBW. This indicates that both sectors of the Indo-Pacific Warm Pool are significantly correlated with basin-wide warming or cooling.

Highlights

The warm pool is normally defined as the enclosed ocean area by an isotherm of a certain sea surface temperature (SST) in the range of 27.5–29 ◦C [1,2,3]
Through detecting oscillations of the eastern edge positions of the western Pacific warm pool (WPWP), it turns out that the South Warm Tongue and the North Warm Tongue were controlled by the annual cycles and were slightly affected by the El Niño onsets, whereas the East Cold Tongue was totally controlled by the El Niño onsets and nearly had no obvious annual cycle [20]
The basin line divides the Indo-Pacific Warm Pool (IPWP) into the Indian Ocean sector and the Pacific Ocean sector, and they are visually different in variations

Summary

Introduction

The warm pool is normally defined as the enclosed ocean area by an isotherm of a certain sea surface temperature (SST) in the range of 27.5–29 ◦C [1,2,3]. Surface heat flux, SST, 20 ◦C isotherm depth, upper ocean heat content, sea surface salinity, warm pool centroids and edges and many other properties of the warm pool were constantly studied [3,4,19,20,21]. The thermal edges of the warm pool were investigated and the chlorophyll-a front in the eastern of the WPWP was detected by the satellite-based ocean color data. Kim et al [4] firstly introduced five warm pool surface properties to delineate the variabilities of the warm pool and contrasted the similarities and differences of the Indian Ocean sector and the Pacific Ocean sector on the seasonal and interannual time scale

Methods

Results

Discussion

Conclusion