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Results are presented from a set of experiments designed to investigate factors that may influence proxy-based reconstructions of large-scale temperature patterns in past centuries. The factors investigated include (1) the method used to assimilate proxy data into a climate reconstruction, (2) the proxy data network used, (3) the target season, and (4) the(More)
Periods of widespread warmth or cold are identified by positive or negative deviations that are synchronous across a number of temperature-sensitive proxy records drawn from the Northern Hemisphere. The most significant and longest duration feature during the last 1200 years is the geographical extent of warmth in the middle to late 20th century. Positive(More)
* After completion of the lesson, please take a moment to fill out the feedback form on our web site Question: How has global temperature changed over time? How does the type or amount of data affect the outcome or trends experienced by a member of the public? Time: Two 45 minute class periods plus additional time for instruction on Excel if necessary.(More)
There has been considerable recent interest in paleoclimate reconstructions of the temperature history of the last millennium. A wide variety of techniques have been used. The interrelation between the techniques is sometimes unclear, as different studies often use distinct data sources as well as distinct methodologies. Recent work 5 is reviewed with an(More)
An annually resolved and absolutely dated ring-width chronology spanning 4,500 y has been constructed using subfossil, archaeological, and living-tree juniper samples from the northeastern Tibetan Plateau. The chronology represents changing mean annual precipitation and is most reliable after 1500 B.C. Reconstructed precipitation for this period displays a(More)
We combine satellite and ground observations during 1950-2011 to study the long-term links between multiple climate (air temperature and cryospheric dynamics) and vegetation (greenness and atmospheric CO(2) concentrations) indicators of the growing season of northern ecosystems (>45°N) and their connection with the carbon cycle. During the last three(More)
sufficient to generate the cranial changes found in mouse models of Down syndrome with larger numbers of triplicated genes. Furthermore, reducing trisomy of these 33 genes to disomy in the Ts65Dn mouse did not eliminate the phenotype. Breeding mice with the deleted chromosome segment with trisomy mouse models is a particularly elegant approach to testing(More)