ARCUS | Witness the Arctic

Witness the Arctic | Spring 1996

PALE Pools Data to Describe Regional Climate Histories

Paleoclimates of Arctic Lakes and Estuaries (PALE) researchers have recently focused on describing the temporal and spatial patterns of paleoclimatic proxies for Beringia (the area between the Indigirka and Mackenzie Rivers) and the north-western Atlantic (Iceland to Hudson Bay).
Two regional workshops convened in October 1995. Workshop results formed the basis of a February 1996 PALE principal investigators (PI) meeting in Boulder; the goals were to:

Compare inferred patterns of climate change for the two regions, and
explore mechanisms that could account for the observed paleoclimatic patterns.

Recognizing the need to incorporate more than lacustrine and estuarine deposits, principal investigators invited scientists working with other key data sets to participate in all three meetings. Regional workshop findings are published in Paleotimes (1996); PI meeting results are being prepared for publication. Categories of ongoing research projects are listed here.

Annual to decadal resolution records

Composite high-resolution records, recovered principally from coastal sites across the Canadian archipelago, have been compiled and compared with other paleo-climatic proxies from the eastern Canadian Arctic. These sediment records are calibrated using the nearest meteorological observations (dating back approximately 50 years) and compared with ice-core chronologies and northern high-latitude tree-ring records.

Century to millennial resolution records

Paleobotanical, sedimentological, and geochemical data from deposits that span up to the last 21,000 calendar years are being examined to describe vegetation and lake-level histories, soil carbon accumulation, and ocean/ice-sheet interactions. These data form the basis of current qualitative interpretations of past climates. Calibration efforts involving modern hydrology/limnology, pollen, diatoms, and stable isotopes will aid future quantitative reconstructions. Research on improved dating methods continues.

Climate modeling

Quantitative modeling efforts have concentrated on ice-sheet mass balance and global climate simulations beginning at 6,000 and 10,000 calendar years using the NCAR GENESIS 2.0 model. The ARCSyM mesoscale model, a revised version of RegCM2, is being used for higher spatial resolution simulations for the two PALE focus regions. Researchers are also developing conceptual models of climate change on the basis of modern synoptic climatology and Atmospheric General Circulation Model (AGCM) results.

For more information, contact Patricia Anderson, co-chair of the PALE Steering Committee (206/543-0569; fax 206/543-3836; pata@u.washington.edu