Pacific Interdecadal Climate Variability: Linkages between the Tropics and the North Pacific during Boreal Winter since 1900

Abstract

This study examines the tropical linkages to interdecadal climate fluctuations over the North Pacific during boreal winter through a comprehensive and physically based analysis of a wide variety of observational datasets spanning the twentieth century. Simple difference maps between epochs of high sea level pressure over the North Pacific (1900-24 and 1947-76) and epochs of low pressure (1925-46 and 1977-97) are presented for numerous climate variables throughout the tropical Indo-Pacific region, including rainfall, cloudiness, sea surface temperature (SST), and sea level pressure. The results support the notion that the Tropics play a key role in North Pacific interdecadal climate variability. In particular, SST anomalies in the tropical Indian Ocean and southeast Pacific Ocean, rainfall and cloudiness anomalies in the vicinity of the South Pacific convergence zone, stratus clouds in the eastern tropical Pacific, and sea level pressure differences between the tropical southeast Pacific and Indian Oceans all exhibit prominent interdecadal fluctuations that are coherent with those in sea level pressure over the North Pacific. The spatial patterns of the interdecadal tropical climate anomalies are compared with those associated with ENSO, a predominantly interannual phenomenon; in general, the two are similar with some differences in relative spatial emphasis. Finally, a published 194-yr coral record in the western tropical Indian Ocean is shown to compare favorably with the twentieth-century instrumental records, indicating the potential for extending knowledge of tropical interdecadal climate variability to earlier time periods.

Observations of Local Positive Low Cloud Feedback Patterns and Their Role in Internal Variability and Climate Sensitivity

“…Large positive SST anomalies are found in the Eastern Pacific and in the North Pacific. The Eastern Pacific anomalies are much more spatially confined than those of a typical ENSO signal, while the North Pacific anomalies are quite similar to the Pacific Decadal Oscillation (Deser et al, 2004). The overall Pacific pattern is strikingly similar to the modeled pattern that represents the impact of AMO on the Pacific (Li et al, 2016; Zhang & Delworth, 2007).…”

An assessment and interpretation of the observed warming of West Antarctica in the austral spring

“…The Niño3 index used by Liu et al (2004) only indirectly relates to the Antarctic sea ice field. Moreover, the Niño3 index does not capture the low frequency, decadal scale variations of tropical climate that could influence the extratropics (Deser et al 2004). …”

“…Zhang et al 1997;Deser et al 2004) or as part of the century scale positive SST trends associated with climate change (e.g. Deser et al 2010); it is likely that both multidecadal climate variability and climate change have contributed to the SST trend pattern evident in Fig.…”

On glacier retreat and drought cycles in the Rocky Mountains of Montana and Canada

“…A positive index (warm western Pacific) is associated with a higher probability for precipitation on the adjacent continent. The PDO may owe some of its power to stimulation by ENSO-related processes (Deser et al, 2004). Also, ENSO-based variations, by themselves, may influence rainfall patterns in much of the West (Ropelewski and Halpert, 1987).…”