ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    The influence of seasonal precipitation and temperature regimes on lake levels in the northeastern United States during the Holocene (2006)
    Cambridge University Press
    Details
    Publication Date: 2006-01-01
    Description: AMS–dated sediment cores combined with ground–penetrating radar profiles from two lakes in southeastern Massachusetts demonstrate that regional water levels rose and fell multiple times during the Holocene when the known climatic controls (i.e., ice extent and insolation) underwent unidirectional changes. The lakes were lowest between 10,000 and 9000 and between 5500 and 3000 cal yr B.P. Using a heuristic moisture-budget model, we explore the hypothesis that changes in seasonal precipitation regimes, driven by monotonic trends in ice extent and insolation, plausibly explain the multiple lake-level changes. Simulated lake levels resulting from low summer precipitation rates match observed low lake levels of 10,000–9000 cal yr B.P., whereas a model experiment that simply shifts the seasonality of the modern Massachusetts precipitation regime (i.e., moving the peak monthly precipitation from winter to summer) produces levels that are ∼2 m lower than today as observed for 5500–3000 cal yr B.P. The influence of the Laurentide ice sheet could explain dry summers before ca. 8000 cal yr B.P. A later shift from a summer-wet to a winter-wet moisture-balance regime could have resulted from insolation-driven changes in the influence of the Bermuda subtropical high. Temperature changes probably further modified lake levels by affecting snowmelt and transpiration.
    Print ISSN: 0033-5894
    Electronic ISSN: 1096-0287
    Topics: Geography , Geosciences
    Published by Cambridge University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 2
    facet.materialart.
    Unknown
    New evidence for high discharge to the Chukchi shelf since the Last Glacial Maximum (2007)
    Cambridge University Press
    Details
    Publication Date: 2007-09-01
    Description: Using CHIRP subbottom profiling across the Chukchi shelf, offshore NW Alaska, we observed a large incised valley that measures tens of kilometers in width. The valley appears to have been repeatedly excavated during sea level lowering; however, the two most recent incisions appear to have been downcut during the last sea level rise, suggesting an increase in the volume of discharge. Modern drainage from the northwestern Alaskan margin is dominated by small, low-discharge rivers that do not appear to be large enough to have carved the offshore drainage. The renewed downcutting and incision during the deglaciation and consequent base level rise implies there must have been an additional source of discharge. Paleoprecipitation during deglaciation is predicted to be at least 10% less than modern precipitation and thus cannot account for the higher discharge to the shelf. Glacial meltwater is the most likely source for the increased discharge.
    Print ISSN: 0033-5894
    Electronic ISSN: 1096-0287
    Topics: Geography , Geosciences
    Published by Cambridge University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 3
    facet.materialart.
    Unknown
    Repeated century-scale droughts over the past 13,000 yr near the Hudson River watershed, USA (2011)
    Cambridge University Press
    Details
    Publication Date: 2011-05-01
    Description: Long-term sediment and ground-penetrating radar data from Davis Pond, a small lake near the Hudson River valley, reveal past droughts in a historically humid region that presently supplies water to millions of people in and around New York City. A minimum of eleven sandy paleoshoreline deposits in the lake date from 13.4 to 0.6 cal ka BP. The deposits span 1500 to 200 yr between bracketing radiocarbon ages, and intrude into lacustrine silts up to 9.0 m below the modern lake surface in a transect of six sediment cores. Three low stands, ca. 13.4–10.9, 9.2 and 8.2 cal ka BP indicate low regional moisture balance when low temperatures affected the North Atlantic region. Consistent with insolation trends, water levels rose from ca. 8.0 cal ka BP to present, but five low stands interrupted the rise and are likely associated with ocean–atmosphere interactions. Similar to evidence from other studies, the data from Davis Pond indicate repeated multi-century periods of prolonged or frequent droughts super-imposed on long-term regional trends toward high water levels. The patterns indicate that water supplies in this heavily populated region have continuously varied at multiple time scales and confirm that humid regions such as the northeastern United States are more prone to severe drought than historically expected.
    Print ISSN: 0033-5894
    Electronic ISSN: 1096-0287
    Topics: Geography , Geosciences
    Published by Cambridge University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...