HR: 0800h
AN: H21A-1312    [Abstracts]
TI: Coupled Oceanic / Atmospheric Variability and United States Streamflow
AU: * Tootle, G
EM: tootleg@uwyo.edu
AF: University of Wyoming Dept. of Civil and Arch. Eng., 1000 E. University Ave. Department 3295 , Laramie, WY 82070 United States
AU: Piechota, T
EM: piechota@unlv.nevada.edu
AF: University of Nevada, Las Vegas Dept. of Civil and Env. Eng., 4505 Maryland Parkway Box 454015 , Las Vegas, NV 89154 United States
AB: A study of the influence of interdecadal, decadal and interannual oceanic / atmospheric influences on streamflow in the U.S. is presented. Unimpaired streamflow was identified for 639 stations in the U.S. for the period 1951 - 2002. The phase (cold / negative or warm / positive) of Pacific Ocean [El Ni¤o-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO)] and Atlantic Ocean [Atlantic Multidecadal Oscillation (AMO) and North Atlantic Oscillation (NAO)] oceanic / atmospheric influences were identified for the year prior to the streamflow year (i.e., long lead-time). Statistical significance testing of streamflow, based on the interdecadal, decadal and interannual oceanic / atmospheric phase (warm / positive or cold / negative), was performed applying the nonparametric rank-sum test. The results show that, in addition to the well-established ENSO signal, the PDO, AMO and NAO influence streamflow variability in the United States. The warm phase of the PDO is associated with increased streamflow in the central and southwest U.S. while the warm phase of the AMO is associated with reduced streamflow in these regions. The positive phase of the NAO and the cold phase of the AMO are associated with increased streamflow in the central United States. Additionally, the coupled effects of the oceanic / atmospheric influences were evaluated, based on the long-term phase (cold / negative or warm / positive) of the interdecadal (PDO and AMO) and decadal (NAO) influences and ENSO. Streamflow regions in the U.S. were identified that respond to these climatic couplings. The results show that the AMO may influence La Ni¤a impacts in the Southeast while the NAO may influence La Ni¤a impacts in the Midwest. By utilizing the streamflow water year and the long lead-time for the oceanic / atmospheric variables, useful information can be provided to streamflow forecasters and water managers.
DE: 1807 Climate impacts
DE: 1833 Hydroclimatology
DE: 1840 Hydrometeorology
DE: 1860 Streamflow
SC: Hydrology [H]
MN: Fall Meeting 2005