Decadal variability in climate and glacier fluctuations on mt baker, washington, usa

Abstract

Climate variability in the Pacific basin has been attributed to large-scale oceanic-atmospheric modulations (e.g. the El Niño-Southern Oscillation (ENSO)) that dominate the weather of adjacent land areas. The Pacific Decadal Oscillation (PDO) and north Pacific index are thought to be indicators of modulations and events in the northeast Pacific. In this study we find that variations in the PDO are reflected in the terminus position of glaciers on Mt Baker, in the northern Cascade Range, Washington. The initiation of retreat and advance phases of six glaciers persisted for 20-30 years, which relate to PDO regime shifts. The result of this study agrees with previous studies that link glacier mass balance changes to local precipitation anomalies and processes in the Pacific. However, the use of mass balance changes and glacier terminus variation for identification of regime shifts in climate indices is complicated by the lack of standardized measuring techniques, differing response times of individual glaciers to changes in climate, geographic and morphometric factors, and the use of assorted climate indices with different domains and time-scales in the Pacific for comparison.

Glacier change in Garibaldi Provincial Park, southern Coast Mountains, British Columbia, since the Little Ice Age

“…The data show that the periods of glacier advance documented in this study are generally cool with variable precipitation, whereas periods of glacier recession are generally warm with variable precipitation, indicating an overall strong dependence on temperature. Our findings also indicate a 5-10 year lag in the frontal response of the glaciers to a change in climate, consistent with previous work in the Pacific Northwest (Kovanen, 2003).…”

Belvedere Glacier, Monte Rosa, Italian Alps: Tongue Thickness and Volume Variations in the Second Half of the 20th Century

“…These phases correspond well with Mount Hood's historical temperature and precipitation patterns, and glacier terminus fluctuations (Fig. 7), as they do elsewhere in the PNW (Kovanen, 2003).…”

“…One such coupled atmosphere-ocean circulation forcing mechanism, the Pacific Decadal Oscillation (PDO) (Mantua et al, 1997;JISAO/SMA Climate Impacts Group, 1999), affects glacier climate on decadal and interdecadal scales throughout the PNW (e.g., McCabe and Fountain, 1995;Bitz and Battisti, 1999;Kovanen, 2003). The PDO (Mantua et al, 1997) is characterized by 20-to 30-year-long phases (JISAO/SMA Climate Impacts Group, 1999) in the north Pacific Ocean.…”

“…Ablation season temperature changes of as little as 0.58C or accumulation season precipitation changes of 10% may be sufficient to alter glacier mass balance (Tangborn, 1980) and ultimately shift termini. Measurable alpine glacier size changes may occur in as few as 1-5 years (Burbank, 1982) to a more decadal scale (Johannesson, 1989;Pelto and Hedlund, 2001;Kovanen, 2003) following climate forcing (Burbank, 1982). Glacier termini measurements have long been used to assess glacier response to climate (Nesje and Dahl, 2000).…”

The response of glaciers to intrinsic climate variability: observations and models of late-Holocene variations in the Pacific Northwest

“…Hodge and others, 1998;Moore and Demuth, 2001;Kovanen, 2003;Nesje and Dahl, 2003;Pederson and others, 2004;Lillquist and Walker, 2006). In particular, for the Pacific Northwest, much is made of the Pacific Decadal Oscillation (PDO).…”