Reconstruction and Dynamics of Interhemispheric Hydroclimate Variability Between the Americas

Lead PI: Jason E Smerdon , Dr. Edward R. Cook , Dr. Richard Seager

Unit Affiliation: Ocean and Climate Physics, Lamont-Doherty Earth Observatory (LDEO)

June 2016 - May 2019
South America ; North America
Project Type: Research

DESCRIPTION: The general goal of this project is to develop a pan-Pacific drought atlas using tree-ring records. This research specifically aims to explore: 1) drought occurrences and dynamics across the Americas; 2) inter-hemispheric regimes of decadal-to-centennial hydroclimate variability; 3) large-scale footprints and temporal properties of extreme events (including responses to volcanism, solar forcing and internal variability); and 4) past hydroclimatic drought events in reference to their underlying dynamics thereby offering insight into some of the most disruptive climatic events of the last millennium.

Hydroclimate patterns will be analyzed for their associated dynamics and diagnosed for their connection to large-scale modes of variability and/or forced patterns of change. Multidecadal hydroclimate anomalies (e.g. megadroughts or pluvials) will be evaluated to determine if they arise from inter-hemispheric-scale climate regimes with coherence across continents or as more local continental-scale phenomena. Similarly, extremes in individual years will be assessed for their dynamic origins and probability of occurrence.

Why this research? Characterizing and understanding large-scale hydroclimate variability during the last millennium is a critical means of evaluating and improving projections of future hydroclimate change.

Why this research now? Two recent developments make the time ripe for significant advances in this area of research. First, fully pan-Pacific reconstructions of last-millennium hydroclimate variability are now within reach. Second, the large and growing ensemble of last-millennium simulations with fully-coupled climate models make dynamic investigations of past hydroclimate change possible thereby providing potentially improved assessments of projected future risks and impacts.

The project will help improve the understanding of extreme climatic events climate and includes a substantive leveraging of international collaboration with South American colleagues in Argentina and Chile, creation of a user-friendly drought atlas, and public outreach on science and education.


National Science Foundation (NSF)




Biology & Paleo Environment (B&PE)



Hydro2k Consortium: Smerdon, J.E., J. Luterbacher, S. Phipps, K.J. Anchukaitis, T.R. Ault, S. Coats, K.M. Cobb, B.I. Cook, C. Colose, T. Felis, A. Gallant, J.H. Jungclaus, B. Konecky, A. LeGrande, S. Lewis, A.S. Lopatka, W. Man, J.S. Mankin, J.T. Maxwell,. "Comparing proxy and model estimates of hydroclimate variability and change over the Common Era," Climate of the Past, v.13, 2017, p. 1851-1900. doi:10.5194/cp-2017-37


pluvials drought extreme events tree rings climate models multidecadal hydroclimate anomalies hydroclimate


Modeling and Adapting to Future Climate