Decadal changes in South Pacific sea surface temperatures and the relationship to the Pacific decadal oscillation and upper ocean heat content

Abstract

Decadal changes in Pacific sea surface temperatures (SSTs) and upper ocean heat content (OHC) remain poorly understood. We present an annual average composite coral Sr/Ca‐derived SST time series extending back to 1791 from Fiji, Tonga, and Rarotonga (FTR) in the Pacific Decadal Oscillation (PDO) sensitive region of the southwest Pacific. Decadal SST maxima between 1805 and 1830 Common Era (C.E.) indicate unexplained elevated SSTs near the end of the Little Ice Age. The mean period of decadal SST variability in this region has a period near 25 years. Decades of warmer (cooler) FTR SST co‐occur with PDO negative (positive) phases since at least ~1930 C.E. and positively correlate with South Pacific OHC (0–700 m). FTR SST is also inversely correlated with decadal changes in equatorial Pacific SST as measured by coral Sr/Ca. Collectively, these results support the fluctuating trade wind‐shallow meridional overturning cell mechanism for decadal modulation of Pacific SSTs and OHC.

Impact of Climatic Factors on Albacore Tuna <i>Thunnus alalunga</i> in the South Pacific Ocean

“…The effect of the PDO is spread Pacific wide where during the positive phase the South Pacific and central North Pacific gyres cool and the equatorial region and Eastern margin become warm and vice versa over decadal time scales [47]. Linsley [47] showed the strong association of the PDO with alterations in the upper oceanic heat of the South Pacific Ocean between 0.5˚S -89.5˚S and 64˚W -147˚E which falls within the albacore tuna distribution for Zone 1, Zone 2 and Zone 3 (Figure 1). Also, the spawning zone for the albacore tuna between 10˚S and 25˚S in the South Pacific Ocean is geolocated within the coverage area of Zone 1, Zone 2 and Zone 3 [38] [41].…”

Abrupt Northward Shift of SPCZ position in the late-1920s Indicates Coordinated Atlantic and Pacific ITCZ Change

“…3C). We use a composite average of three coral δ 18 O records from Fanning (Cobb et al, 2013), Palmyra (Cobb et al, 2013) and Maiana (Urban et al, 2000) as a coral δ 18 O-based index of equatorial ENSO state (termed FPM; see Linsley et al, 2015).…”

Untitled

“…3C). We use a composite average of three coral δ 18 O records from Fanning , Palmyra and Maiana (Urban et al, 2000) as a coral δ 18 O-based index of equatorial ENSO state (termed FPM; see Linsley et al, 2015).…”