Climatic fluctuations and the timing of west coast streamflow
- San Diego State Univ., CA (United States)
- Scripps Inst. of Oceanography, La Jolla, CA (United States)
- State of California Dept. of Water Resources, Sacramento, CA (United States)
Since about 1950 there has been a trend in the California Sierra Nevada toward a decreasing portion of the total annual streamflow occurring during April through July, while the streamflow during autumn and winter has increased. This trend not only has important ramifications with regard to water mangement, it also brings up the question of whether this represents a shift toward earlier release of the snowpack resulting from greenhouse warming. Therefore, the observed record has been examined in terms of relative influences of temperature and precipitation anomalies on the timing of streamflow in this region. To carry out this study, the fraction of annual streamflow (called the fractional streamflow) occurring in November-January (NDJ), February-April (FMA), and May-July (MJJ) at low, medium and high elevation basins in California and Oregon was examined. Linear regression models were used to relate precipitation and temperature to the fractional streamflow at the three elevations for each season. Composites of monthly temperature and precipitation were employed to further examine the fractional streamflow in its high and low tercile extremes. Long time series of climatic and hydrologic data were also looked at to infer the causes in the trend toward earlier runoff. 14 refs., 13 figs., 4 tabs.
- OSTI ID:
- 6884286
- Journal Information:
- Journal of Climate; (United States), Vol. 5:12; ISSN 0894-8755
- Country of Publication:
- United States
- Language:
- English
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