Paleoclimatic significance of insoluble microparticle records from Canadian Arctic and Greenland ice cores
The past and present variability of climate in the Arctic region is investigated using ice core records of atmospheric dust (microparticles) and volcanic aerosols developed from the Canadian Arctic and Greenland. A high-resolution, 10 4-year long proxy record of atmospheric dust deposition is develo...
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University of New Hampshire Scholars' Repository
1999
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| Online Access: | https://scholars.unh.edu/dissertation/2088 https://scholars.unh.edu/cgi/viewcontent.cgi?article=3087&context=dissertation |
| Summary: | The past and present variability of climate in the Arctic region is investigated using ice core records of atmospheric dust (microparticles) and volcanic aerosols developed from the Canadian Arctic and Greenland. A high-resolution, 10 4-year long proxy record of atmospheric dust deposition is developed from an ice core (P95) drilled through the Penny Ice Cap, Baffin Island. Snowpit studies indicate that dust deposited on the Penny Ice Cap are representative of background mineral aerosol, and demonstrate that the variability of dust fallout is preserved in the P95 core at multi-annual to longer time scales. The P95 dust record reveals a significant increase in dust deposition on the Penny Ice Cap between ca 7500--5000 yr ago. This increase was driven by early to mid-/late Holocene transformations in the Northern Hemisphere landscape (ice cover retreat, postglacial land emergence) and climate (transition to colder, drier conditions) that led to an expansion of sources and enhanced eolian activity. Comparison between dust records in the P95 and GISP2 (Greenland) ice cores shows an increasing divergence between the two records beginning ca 7500 years ago. The effects of Northern Hemisphere atmospheric circulation and snow cover extent on atmospheric dust deposition in the Arctic are evaluated by comparing the P95 dust record with observational data. Changes in dust deposition are strongly linked to modes of the Northern Hemisphere winter circulation. Most prominently, an inverse relationship between the P95 dust record and the intensity of the winter Siberian High accounts for over 50% of the interannual variance of these two parameters over the period 1899--1995. On inter- to multi-annual time scales, the P95 dust record is significantly anticorrelated with variations in spring, and to a lesser extent fall, snow cover extent in the mid-latitude interior regions of Eurasia and North America. These relationships account for an estimated 10 to 20% of variance in the P95 dust record. An empirical orthogonal function ... |
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