Review of: “Ice core records of biomass burning tracers (levoglucosan, dehydroabietic and vanillic acids) from Aurora Peak in Alaska since 1660s: A new dimension of forest fire activities in the Northern Hemisphere”

Abstract. A 180 m long (343 years) ice core was drilled in the saddle of Aurora Peak in Alaska (63.52∘ N, 146.54∘ W; elevation: 2825 m) and studied for biomass-burning tracers. Concentrations of levoglucosan and dehydroabietic and vanillic acids exhibit multidecadal variability, with higher spikes in 1678, 1692, 1695, 1716, 1750, 1764, 1756, 1834, 1898, 1913, 1966 and 2005 CE. Historical trends of these compounds showed enhanced biomass-burning activities in the deciduous broadleaf forests, boreal conifer forests, and/or tundra woodland and mountain ecosystems before the 1830s and after the Great Pacific Climate Shift (GPCS). The gradually elevated level of dehydroabietic acid after the GPCS is similar to p-hydroxybenzoic acid (p-HBA) from the Svalbard ice core, suggesting common climate variability in the Northern Hemisphere. The periodic cycle of levoglucosan, which seemed to be associated with the Pacific Decadal Oscillation (PDO), may be more involved with the long-range atmospheric transport than other species. These compounds showed significant correlations with global lower-tropospheric temperature anomalies (GLTTAs). The relations of the biomass-burning tracers with the PDO and GLTTA in this study suggest that their emission, frequency and deposition are controlled by the climate-driven forces. In addition, historical trends of dehydroabietic and vanillic acids (burning products of resin and lignin, respectively) from our ice core demonstrate the Northern Hemispheric connections to the common source regions as suggested from other ice core studies from Svalbard, Akademii Nauk and Tunu Greenland in the Northern Hemisphere.

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Reinterpretation of Pingos in Antarctica

Quaternary Research ◽

10.1016/0033-5894(89)90037-9 ◽

1989 ◽

Vol 32 (1) ◽

pp. 114-116 ◽

Cited By ~ 9

Author(s):

Sean J. Fitzsimons

Keyword(s):

Northern Hemisphere ◽

Ice Core ◽

Sedimentary Processes ◽

Thermal Erosion ◽

Environmental Requirements ◽

Tension Cracks ◽

Vestfold Hills ◽

Geologic Setting

AbstractIn 1983 pingos were reported in the Vestfold Hills, Antarctica. The features form dome-shaped hills up to 4 m high and 12 m in diameter and occur on an ice-cored moraine. Their form, structure, and sedimentary processes observed on the surface of the moraine, together with a consideration of the environmental requirements for pingo growth preclude their origin as pingos. They appear to be residual landforms that have formed on the surface of the moraine as the ice core has been destroyed by ablation and thermal erosion. The previous interpretation of the features has relied on the shape of the hills and their occurrence in a similar geologic setting to pingos in the Northern Hemisphere. The interpretation appears to have misinterpreted tension cracks and coherent slumping of sediment as dilation cracks and as evidence for the extrusion of a central sediment plug. Pingos on supraglacial debris have not been described from any other locations and it seems that their formation is inconsistent with the ablation of the ice core of moraines.

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Reconstructing an Interdecadal Pacific Oscillation Index from a Pacific Basin–Wide Collection of Ice Core Records

Journal of Climate ◽

10.1175/jcli-d-20-0455.1 ◽

2021 ◽

Vol 34 (10) ◽

pp. 3839-3852

Author(s):

Stacy E. Porter ◽

Ellen Mosley-Thompson ◽

Lonnie G. Thompson ◽

Aaron B. Wilson

Keyword(s):

Ice Core ◽

Ice Cores ◽

Tropical Pacific ◽

Ice Age ◽

Pacific Basin ◽

Interdecadal Pacific Oscillation ◽

The Pacific ◽

Instrumental Period ◽

The Tropical Pacific ◽

Ice Core Records

AbstractUsing an assemblage of four ice cores collected around the Pacific basin, one of the first basinwide histories of Pacific climate variability has been created. This ice core–derived index of the interdecadal Pacific oscillation (IPO) incorporates ice core records from South America, the Himalayas, the Antarctic Peninsula, and northwestern North America. The reconstructed IPO is annually resolved and dates to 1450 CE. The IPO index compares well with observations during the instrumental period and with paleo-proxy assimilated datasets throughout the entire record, which indicates a robust and temporally stationary IPO signal for the last ~550 years. Paleoclimate reconstructions from the tropical Pacific region vary greatly during the Little Ice Age (LIA), although the reconstructed IPO index in this study suggests that the LIA was primarily defined by a weak, negative IPO phase and hence more La Niña–like conditions. Although the mean state of the tropical Pacific Ocean during the LIA remains uncertain, the reconstructed IPO reveals some interesting dynamical relationships with the intertropical convergence zone (ITCZ). In the current warm period, a positive (negative) IPO coincides with an expansion (contraction) of the seasonal latitudinal range of the ITCZ. This relationship is not stationary, however, and is virtually absent throughout the LIA, suggesting that external forcing, such as that from volcanoes and/or reduced solar irradiance, could be driving either the ITCZ shifts or the climate dominating the ice core sites used in the IPO reconstruction.

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