9631538 Anderson A high-resolution record of climate changes, reconstructed from lake sediments and shoreline features in Estancia Basin, central New Mexico, has documented a land-based record of large and abrupt shifts in climate during the latest Pleistocene. Nine major fluctuations in lake level between ~24 and ~12 kyr correspond, within errors of dating, to major isotopic shifts between stadial and interstadial conditions in Greenland ice cores. Four of the lowstands coincide with changes in ocean circulation and zones of anoxic sediment in Santa Barbara Basin, at the same latitude. Estancia Basin also contains a record of changes in hydrologic balance for conditions of extreme, dry climate in the mid-Holocene. Previously funded research is providing the temporal, spatial, compositional, and hydrochemical data and framework needed for coupling hydrologic responses to Estancia Basin to changes in atmospheric parameters through the application of physically based, landscape-scale hydrologic models. This project will obtain the temporal, spatial, and geomorphic data needed to define the mid-Holocene hydrologic response and subsequent changes in hydrologic meteorological system will be employed in order to modify and apply existing hydrologic models. We propose to use the highly responsive hydrologic setting and a tested physically based model to link the extreme changes in climate recorded in Estancia Basin with changes in atmospheric conditions and climatic variables. Output from high-resolution atmospheric models will be used as input to the hydrologic models in simulations of key climate events. Hydrologic simulations for key climatic events, including stadials, interstadials, and mid- to late Holocene climate changes will be reconciled with output from atmospheric models, with the long-term objective of testing hypotheses for explaining abrupt, decade- to millenium-scale changes in climate. ??
