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Multi-proxy Data (multi-proxy + data)
Selected AbstractsSpring,summer temperature reconstruction in western Norway 1734,2003: a data-synthesis approachINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 15 2003P. Ø. Nordli Abstract A series of spring,summer (April,August) temperatures was reconstructed for the period 1734,1923 for western Norway based on multi-proxy data. For the period 1734,1842 the long-term variations were based on terminal moraines in front of two southern Norwegian glaciers, whereas the annual variations were based on grain-harvest data extracted from farmers' diaries. For the period 1843,1867 the spring,summer temperatures were reconstructed solely from diaries overlapping instrumental observations. All the results were incorporated into one series for the period 1734,2003 to form the Vestlandet composite series. The reconstruction method using terminal-moraine sequences was tested against the modern instrumental Bergen series for the periods of moraine formations in front of the glaciers. The agreement with the instrumental series was good, with the mean difference for all periods being only 0.2 °C. Analyses of decadal variations in western Norway revealed three periods of low spring,summer temperatures: around 1740, in the first decade of the 19th century, and in the 1830s. These periods are well known from historic records as periods of starvation, during which the use of bark bread became common. Copyright © 2003 Royal Meteorological Society [source] Did the Indo-Asian summer monsoon decrease during the Holocene following insolation?,JOURNAL OF QUATERNARY SCIENCE, Issue 7 2010Manish Tiwari Abstract A few studies from the western Arabian Sea indicate that the Indian summer (or southwest) monsoon (ISM), after attaining its maximum intensity at ca. 9,ka, declined during the Holocene, as did insolation. In contrast, earlier and later observations from both the eastern and the western Arabian Sea do not support this inference. Analysis of multiple proxies of productivity in a new sediment core from the western Arabian Sea fails to confirm the earlier, single-proxy (e.g. abundance of Globigerina bulloides) based, inference of the Holocene weakening of ISM, following insolation. The reason for the observed decreasing trend in foraminiferal abundance , the basis for the earlier inference , could be the favouring of silicate rather than carbonate productivity by the increased ISM wind strength. Although ISM exhibits several multi-millennial scale fluctuations, there is no evidence from several multi-proxy data to conclude that it declined during the Holocene; this is consistent with the phase lag analysis of longer time series of monsoon proxies. Thus, on sub-Milankovitch timescales, ISM did not follow insolation, highlighting the importance of internal feedbacks. A comparison with East Asian summer monsoon (EASM) records suggests that both ISM and EASM varied in unison, implying common forcing factors on such longer timescales. Copyright © 2010 John Wiley & Sons, Ltd. [source] Peat multi-proxy data from Männikjärve bog as indicators of late Holocene climate changes in EstoniaBOREAS, Issue 1 2007UULLE SILLASOO Sillasoo, Ü., Mauquoy, D., Blundell, A., Charman, D., Blaauw, M., Daniell, J. R. G., Toms, P., Newberry, J., Chambers, F M. & Karofeld, E. 2007 (January): Peat multi-proxy data from Männikjärve bog as indicators of late Holocene climate changes in Estonia. Boreas, Vol. 36, pp. 20,37. Oslo. ISSN 0300,9483. As part of a wider project on European climate change over the past 4500 years, a 4.5-m peat core was taken from a lawn microform on Männikjärve bog, Estonia. Several methods were used to yield proxy-climate data: (i) a quadrat and leaf-count method for plant macrofossil data, (ii) testate amoebae analysis, and (iii) colorimetric determination of peat humification. These data are provided with an exceptionally high resolution and precise chronology. Changes in bog surface wetness were inferred using Detrended Correspondence Analysis (DCA) and zonation of macrofossil data, particularly concerning the occurrence of Sphagnum balticum, and a transfer function for water-table depth for testate amoebae data. Based on the results, periods of high bog surface wetness appear to have occurred at c. 3100,3010,2990,2300, 1750,1610, 1510, 1410, 1110, 540 and 310 cal. yr BP, during four longer periods between c. 3170 and 2850 cal. yr BP, 2450 and 2000 cal. yr BP, 1770 and 1530 cal. yr BP and in the period from 880 cal. yr BP until the present. In the period between 1770 and 1530 cal. yr BP, the extension or initiation of a hollow microtope occurred, which corresponds with other research results from Mannikjarve bog. This and other changes towards increasing bog surface wetness may be the responses to colder temperatures and the predominance of a more continental climate in the region, which favoured the development of bog micro-depressions and a complex bog microtopography. Located in the border zone of oceanic and continental climatic sectors, in an area almost without land uplift, this study site may provide valuable information about changes in palaeohydrological and palaeoclimatological conditions in the northern parts of the eastern Baltic Sea region. [source] | ||||||||||