CGRG Bibliography of Canadian Geomorphology
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Author : Frechette, B.; de Vernal, A.; Miller, G.H.; and Wolfe, A.P.
Date : 2007.
Title : Cloud cover changes in the eastern Baffin Island and southern Greenland regions since 7000 cal. years BP: pollen evidence.
Publication : CMOS, CGU, AMS Congress 2007. "Air, Ocean, Earth and Ice on the Rock". May 28 - June 1, 2007. St. John's Congress Centre, Newfoundland and Labrador, Canada.
Issue :
Page(s) : C02-2B5 .3.
Abstract
Canonical correspondence analysis of 831 modern pollen spectra from middle to high latitudes of Canada and Greenland illustrate close relationships with both July air temperature and cloud cover. The amount of sunshine (inversely proportional to cloud cover) seems to be one of the most important climate parameter that controls vegetation growth in Arctic areas and pollen production. On this basis we have used the modern analogue technique (MAT) to simultaneously reconstruct the percentage of July cloud cover and July air temperature. The validation exercises show that MAT permits estimation of July cloud cover and temperature with an accuracy of ±2.3% and and ±1.4°C, respectively. This approach has been applied to Holocene pollen sequences of eastern Baffin Island (Akvaqiak Lake, 66°47’N, 63°57’W, 45 m asl) and southwestern Greenland (Qipisarqo Lake, 61°00’N, 47°45’W, 7 m asl). For the interval spanning 7000 cal. years BP to present, the reconstructions indicate limited changes on eastern Baffin Island with a slight decrease of July cloud cover and air temperature between 7000 to 5000 cal years BP, followed by stable conditions for the remainder of the Holocene. In contrast, the southwest Greenland record reveals that July cloud cover increased of 9% and that July air temperature has progressively decreased of from 12.0 to 8.5°C since 7000 years. The results suggest spatial diffence in Holocene climate trends. The contrasting cloud cover and temperature estimates from both sides of Labrador Sea and Davis Strait points to the determinant influence of North Atlantic waters as moisture and heat source over southern Greenland, whereas Baffin Island apparently remained under relatively uniform Arctic influence, notably through the Baffin Land and Labrador currents.
Bibliography of Canadian Geomorphology