Holocene Hydrologic Variability - Providing a Baseline to Evaluate Current and Future Conditions
Abstract
We analyzed proxy-based hydrologic reconstructions from 22 terrestrial sediment records in North America and Central America to quantify hydrologic variability on decadal to centennial timescales over the last 7,000 years, with particular focus on the last 2,000 years. Analyses are based on records of stable isotopes, physical properties, and multivariate analysis of pollen assemblages that record different aspects of regional hydrology, including mean annual precipitation, wetland hydroperiod, and changes in water availability. Specific regions showing large-scale centennial variability include the North Pacific (precipitation related to intensity and position of the Aleutian Low), the southeastern United States (wetland hydroperiod related to position of the Bermuda High and Intertropical Convergence Zone [ITCZ]), mid-Atlantic region (rainfall and river discharge related to ocean-atmosphere circulation patterns), and Central America (precipitation related to the Central American Monsoon and ITCZ). These records provide a long-term context to evaluate current and future hydrologic changes associated with climate and land use change and are being used to establish baseline levels of hydrologic variability during the Medieval Climate Anomaly and Little Ice Age for assessment of recent trends in rainfall.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFMPP21B1987W
- Keywords:
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- 0473 BIOGEOSCIENCES / Paleoclimatology and paleoceanography;
- 4901 PALEOCEANOGRAPHY / Abrupt/rapid climate change;
- 4952 PALEOCEANOGRAPHY / Palynology