Contract #DACW 72-78-Q-0046 / US Army Coastal Engineering Research Center Requisition Purchase Request #IWR-B-78-119 / The objectives of this report are, first, to summarize the findings to date of the dendroclimatic work performed by our research team at the University of Arizona with respect to the broad patterns of climatic variations over North America since 1600 AD. A secondary objective, as stated in the contract, is to select set(s) of those past climatic patterns which most closely resemble or provide a perspective for conditions of climatic variability expressed as possessing a substantial degree of mobility of occurrence by the National Defense University (1978) study of climatic changes.

Trends in streamflow extremes at a regional scale linked to the possible influences of four major oceanic-atmospheric oscillations are analyzed in this study. Oscillations considered include: El Niño Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO), and North Atlantic Oscillation (NAO). The main emphasis is low flows in the South-Atlantic Gulf region of the United States. Several standard drought indices of low flow extremes during two different phases (warm/positive and cool/negative) of these oscillations are evaluated. Long-term streamflow data at 43 USGS sites in the region from the Hydro-Climatic Data Network that are least affected by anthropogenic influences are used for analysis. Results show that for ENSO, low flow indices were more likely to occur during La Niña phase; however, longer deficits were more likely during El Niño phase. Results also show that for PDO (AMO), all (most) low flow indices occur during the cool (warm) phase. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection