Multi- and Quasi-Decadal Variations of Sea Surface Temperature in the North Atlantic

Abstract

The multi-and quasi-decadal variabilities of the sea surface temperature (SST) anomaly over the North Atlantic are investigated by means of two-dintensional propagating CEOR Forty-six years of the COADS SST dataset from 1947 to 1992 are used. After removing the monthly climatology and four-year low-pass filtering the SST anomaly is submitted to CEOR The total variance of the three largest modes accounts for 87.0% of the total variance. Mode 1 is a very slow oscillation with an approximate 42-yr period and has basinwide spatial evolution, with alternate warm and cold anomalies appearing off Newfoundland and migrating northward until they disappear south of Greenland. The center of action of the anomalies both occur in the vicinity of the Labrador Sea. Newfoundland, and south of Greenland where deep-water formation takes place. Mode 2 + 3 is a quasi-decadal ftuctuation with an approximate 14-yr period. Mode 2 + 3 contains quasidecadal timescales with alternating warm and cold anomalies propagating from the Labrador Sea eastward following the North Atlantic Current and the subpolar gyre.

Air temperature impacts over Eastern North America and Europe associated with low‐frequency North Atlantic SST variability

“…However, the lack of an authoritative consensus definition of the AMO in the scientific literature to date precludes us from definitively claiming that the leading mode and the AMO are one and the same. PC2 has spectral energy concentrated in the 6-14 year period (Figure 1(e)), in agreement with the work of Mizoguchi et al (1999).…”

“…The third and higher-order modes are not discussed in the present examination to highlight the modes clearly associated with the AMO and the NAO only. Some EOF analyses (namely Mizoguchi et al, 1999) of North Atlantic SST have found a quasi-decadal signal manifesting itself as the splitting of modes 2 and 3; this did not occur in the present examination. Subsequently, the two PC time series were each detrended and scaled by their respective standard deviations.…”

“…The current work offers a unified investigation of North Atlantic SST modes, the overlying atmospheric circulation, and air temperature impacts over adjacent landmasses. In effect, this study offers a bridge connecting previous works that have diagnosed North Atlantic SST variability (Deser and Blackmon, 1993;Delworth, 1996;Mizoguchi et al, 1999) with treatments of SST-related climate variability (e.g. Sutton and Hodson, 2005; hereafter SH05) and NAO impacts (Hurrell, 1995;Wallace and Thompson, 2002;Cohen and Barlow, 2005) in the trans-North Atlantic region.…”

“…Later studies refer to different incarnations of this leading mode as the Atlantic multi-decadal oscillation (AMO; Kerr, 2000;Enfield et al, 2001). Significant SST modes also exist at quasi-decadal (Mizoguchi et al, 1999) and inter-annual timescales (Delworth, 1996); these secondary modes have been linked to North Atlantic Oscillation (NAO) variability (Wu and Gordon, 2002;Justino and Peltier, 2005).…”

Fine Pattern of Natural Modes in Sea Surface Temperature Variability: 1985–2003

“…They also identified another 7-8-yr oscillation, which involves the entire double-gyre circulation of the North Atlantic. Enfield and Mestas-Nuñez (1999) summarized the classic features normally associated with the Pacific ENSO mode as follows: (i) a region of intense amplitude within Ϯ10°o f the equator and east of the date line, which decreases to small amplitude over a wide, wedge-shaped region 3 Multidecadal NA 3 Interdecadal Eastern NP 3 Interdecadal Eastern TP 3 Interdecadal Central TP 3 Multidecadal NP 3 Interannual to interdecadal SA Mizoguchi et al (1999) COADS ( Lohmann and Latif (2005).…”