HR: 1340h
AN: H33D-1409    [Abstracts]
TI: Effects of Incorporating a Climate Index into the Upper Klamath Operational Water Supply Forecast: Trans-Nino Index
AU: * Kennedy, A M
EM: kenna@pdx.edu
AF: Environmental Sciences and Resources Program, Portland State University, PO Box 751, Portland, OR 97207 United States
AU: Garen, D C
EM: david.garen@por.usda.gov
AF: USDA, Natural Resource Conservation Service, National Water and Climate Service, 1201 Lloyd Blvd., Portland, OR 97232 United States
AU: Koch, R W
EM: kochr@pdx.edu
AF: Environmental Sciences and Resources Program, Portland State University, PO Box 751, Portland, OR 97207 United States
AB: This research investigates large-scale climate variables affecting inter-annual hydrologic variability of streams flowing into Upper Klamath Lake, Oregon. Six indexes - the Pacific North American Pattern, Southern Oscillation Index, Pacific Decadal Oscillation (PDO), Multivariate ENSO Index, Nino 3.4, and a revised Trans-Nino Index (TNI) - were evaluated independently for their ability to explain inter-annual variation of the Upper Williamson River, Sprague River, Upper Klamath Lake net inflow, and Crater Lake snow water equivalent (SWE). The TNI, which measures the sea surface temperature gradient between region Nino 1+2 and region Nino 4, was the only index to show significant correlations during the current warm phase of the PDO. During the warm PDO phase (1978-present), the averaged October through December TNI was strongly correlated (  = 0.05) with the following April through September Upper Williamson River discharge (r = 0.73), Sprague River discharge (r = 0.65), net inflow to Upper Klamath Lake (r = 0.68), and moderately correlated with observed Crater Lake April 1st SWE (r = 0.52). These results suggest that warm PDO phase equatorial sea surface temperature gradients, as opposed to mean sea surface temperature or sea-level pressure patterns, explain a large portion of hydrologic variability observed in the Upper Klamath basin. Furthermore, additional analysis indicated regional-scale correlations, which may extend the usefulness of the TNI outside of the Upper Klamath basin. Thus, the TNI may prove useful for long lead stream flow forecast operations, ecosystem scale modeling, and a variety of other environmental science applications.
UR: http://www.web.pdx.edu/~kenna/klamath_public/klamath_home.php
DE: 1807 Climate impacts
DE: 1816 Estimation and forecasting
DE: 1833 Hydroclimatology
DE: 1860 Streamflow
DE: 4215 Climate and interannual variability (1616, 1635, 3305, 3309, 4513)
SC: Hydrology [H]
MN: Fall Meeting 2005