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Palaeotemperature Records (palaeotemperature + record)
Selected AbstractsTEMPERATURE PROXY RECORDS COVERING THE LAST TWO MILLENNIA: A TABULAR AND VISUAL OVERVIEWGEOGRAFISKA ANNALER SERIES A: PHYSICAL GEOGRAPHY, Issue 1 2009FREDRIK CHARPENTIER LJUNGQVIST ABSTRACT. Proxy data are our only source of knowledge of temperature variability in the period prior to instrumental temperature measurements. Until recently, very few quantitative palaeotemperature records extended back a millennium or more, but the number is now increasing. Here, the first systematic survey is presented, with graphic representations, of most quantitative temperature proxy data records covering the last two millennia that have been published in the peer-reviewed literature. In total, 71 series are presented together with basic essential information on each record. This overview will hopefully assist future palaeoclimatic research by facilitating an orientation among available palaeotemperature records and thus reduce the risk of missing less well-known proxy series. The records show an amplitude between maximum and minimum temperatures during the past two millennia on centennial timescales ranging from c. 0.5 to 4°C and averaging c. 1.5,2°C for both high and low latitudes, although these variations are not always occurring synchronous. Both the Medieval Warm Period, the Little Ice Age and the 20th century warming are clearly visible in most records, whereas the Roman Warm Period and the Dark Age Cold Period are less clearly discernible. [source] Response of mid-latitude North Pacific surface temperatures to orbital forcing and linkage to the East Asian summer monsoon and tropical ocean,atmosphere interactions,JOURNAL OF QUATERNARY SCIENCE, Issue 8 2009Masanobu Yamamoto Abstract We present a palaeoceanographic perspective of the North Pacific during the last two glacial cycles based on U -derived palaeotemperature records of IMAGES Core MD01-2421 off the coast of central Japan and cores from the Ocean Drilling Program (ODP) Sites 1014 and 1016 off the coast of California. The sea surface temperature (SST) differences between ODP Sites 1014 and 1016 (,SSTnortheastern Pacific (NEP),=,SSTODP1014 , SSTODP1016) indicate the intensity of the California Current. Comparison of ,SSTNEP and the SST from Core MD01-2421 revealed anti-phase variation; high ,SSTNEP (indicating weakening of the California Current) corresponded to low SST at the Japan margin (indicating the southward displacement of the north-western Pacific subarctic boundary and weakening of the Kuroshio Extension), and vice versa. This finding suggests that the intensity of the North Pacific subtropical gyre circulation has varied in response to precessional forcing and that this response has been linked with changes in tropical ocean,atmosphere interactions. In the precessional cycle, the SST variation derived from Core MD01-2421 lags ca. 2.5,4,ka behind the variations shown by Hulu and Sanbao stalagmite ,18O records and by the pollen temperature index from Core MD01-2421, suggesting out-of-phase variations of the North Pacific subtropical gyre circulation and the East Asian summer monsoon. These findings indicate that the behaviour of interactions between tropical ocean,atmosphere dynamics and the East Asian summer monsoon may have varied in response to the precessional cycle. Copyright © 2009 John Wiley & Sons, Ltd. [source] Quantitative palaeotemperature records inferred from fossil pollen and chironomid assemblages from Lake Gilltjärnen, northern central Sweden,JOURNAL OF QUATERNARY SCIENCE, Issue 8 2006Karin Antonsson Abstract Palaeotemperature reconstructions based on radiocarbon-dated fossil pollen and chironomid stratigraphies obtained from Lake Gilltjärnen provide evidence of climate changes during the last 11,000 years in the boreal zone of northern central Sweden. The records show consistent trends during the early and mid-Holocene, indicating low temperatures at 11,000,10,000,cal.,yr,BP, followed by a rising trend and a period of maximum values from about 7000 to 4000,cal.,yr,BP. At 3000,cal.,yr,BP the chironomid-inferred temperature values rise abruptly, deviating from the late-Holocene cooling trend indicated by the pollen-based reconstruction and most of the other palaeotemperature records from central Scandinavia, probably as a result of local limnological changes in Lake Gilltjärnen and its catchment. Comparison of the present results with a lake-level reconstruction from Lake Ljustjärnen, ca. 100,km southwest of Lake Gilltjärnen, shows that the low early-Holocene temperatures were associated with high lake-levels at 10,500,8500,cal.,yr,BP, whereas low lake-levels and dry conditions prevailed during the period of high temperatures at between 7500 and 5000,cal.,yr,BP, probably due to high summer evapotranspiration and lower precipitation. Copyright © 2006 John Wiley & Sons, Ltd. [source] Oxygen isotope and palaeotemperature records from six Greenland ice-core stations: Camp Century, Dye-3, GRIP, GISP2, Renland and NorthGRIPJOURNAL OF QUATERNARY SCIENCE, Issue 4 2001Sigfus J. Johnsen Abstract Oxygen isotope variations spanning the last glacial cycle and the Holocene derived from ice-core records for six sites in Greenland (Camp Century, Dye-3, GRIP, GISP2, Renland and NorthGRIP) show strong similarities. This suggests that the dominant influence on oxygen isotope variations reflected in the ice-sheet records was regional climatic change. Differences in detail between the records probably reflect the effects of basal deformation in the ice as well as geographical gradients in atmospheric isotope ratios. Palaeotemperature estimates have been obtained from the records using three approaches: (i) inferences based on the measured relationship between mean annual ,18O of snow and of mean annual surface temperature over Greenland; (ii) modelled inversion of the borehole temperature profile constrained either by the dated isotopic profile, or (iii) by using Monte Carlo simulation techniques. The third of these approaches was adopted to reconstruct Holocene temperature variations for the Dye 3 and GRIP temperature profiles, which yields remarkably compatible results. A new record of Holocene isotope variations obtained from the NorthGRIP ice-core matches the GRIP short-term isotope record, and also shows similar long-term trends to the Dye-3 and GRIP inverted temperature data. The NorthGRIP isotope record reflects: (i) a generally stronger isotopic signal than is found in the GRIP record; (ii) several short-lived temperature fluctuations during the first 1500 yr of the Holocene; (iii) a marked cold event at ca. 8.2 ka (the ,8.2 ka event'); (iv) optimum temperatures for the Holocene between ca. 8.6 and 4.3 ka, a signal that is 0.6, stronger than for the GRIP profile; (v) a clear signal for the Little Ice Age; and (vi) a clear signal of climate warming during the last century. These data suggest that the NorthGRIP stable isotope record responded in a sensitive manner to temperature fluctuations during the Holocene. Copyright © 2001 John Wiley & Sons, Ltd. [source] | ||||||||||