Tree-Ring View of “Nameless Oscillation” in California Streamflow

Category: Time:
Wednesday, November 26, 2014 - 12:00 to 13:00
Access:
public
Room: Speaker:
Dave Meko
Affiliation:
LTRR, University of Arizona
Contact:
Margaret Evans
Calendar Status:
tentative

An ongoing severe drought in California highlights the importance of understanding and predicting multi-year swings in moisture availability on the scale of large watersheds.  The 20th and early 21st centuries have seen large oscillations with an average period of about 15 years in annual flows of the Sacramento and San Joaquin Rivers, two major sources of water supply for the state of California.  A meeting sponsored by the California Department of Water Resources (CADWR) was held in La Jolla, California, this past May specifically to address hydrologic and climatological aspects of the rhythm – referred to for lack of a better alternative as the “Nameless Oscillation”.  The wet epochs have been linked to atmospheric rivers, in which a large fraction of the annual precipitation falls in a few major storms. CADWR recently sponsored a tree-ring study of streamflow variability for a network of rivers in California and Oregon.  Streamflow reconstructions from that study and others in the western USA are applied in this talk for a temporal and spatial perspective on cycles in California runoff.