PRECIPITATION VARIABILITY IN THE NORTHEAST UNITED STATES DURING THE LATE HOLOCENE AND ITS RELATIONSHIP TO TELECONNECTION PATTERNS

Changing hydrologic conditions of populated regions are a concern in light of current global climate change. As regions become dryer or wetter, problems such as water shortages or flooding may occur with higher frequency. Often, regional climate conditions can be correlated to other areas through teleconnection patterns. Therefore, a more thorough understanding of teleconnection patterns' variability and their relationships to precipitation may shed light on interplays of droughts and wet periods over large geographic areas. Unfortunately the behavior of many teleconnection patterns and their relationship to hydroclimate is limited due to the relatively short length of instrumental records. Sediment deposits preserved in lakes can extend climate records to more completely observe the behavior of these patterns over time. We will present precipitation proxy data from the Northeast United States as reconstructed from varved (annually-laminated) lake sediments over the last millennium. In each case, lamination thicknesses are correlated to precipitation in the region, either through surface runoff and enhanced sediment transport, or through geochemical controls on carbonate precipitation. These records have significant relationships to major teleconnection patterns, most notably the Pacific/North American Pattern (PNA). Spectral analyses are utilized to better understand the cyclic components involved in hyrologic variability over the last millennium. Coherence in the PNA spectral band suggests this as a dominant control on hydroclimate in the Northeast during the late Holocene.