2002 Annual

Thursday, 17 January 2002: 11:45 AM
Uncertainty analysis of California streamflow using multiple climate change scenarios
Norman L. Miller, Univ. of Calfornia, Berkeley National Lab., Berkeley, CA; and K. E. Bashford
Poster PDF (1.0 MB)
Recent reports based on climate change scenarios have suggested that California will be subjected to increased wintertime streamflow and decreased reservoir storage. Understanding the range of potential climatological mean-monthly streamflow response is investigated by using the Sacramento Soil Moisture Accounting Model with the Anderson Snow Model forced by precipitation and temperature input from a number of climate change scenarios. An evaluation of very wet, wet, normal, dry, and very dry year types derived from 100 years of historical watershed area-average annual precipitation is used to analyze projected scenario wet-dry distributions. Six GCM-simulated and six specified incremental climate scenarios are evaluated for a set of California river basins that extend from the coastal mountains and Sierra Nevada northern region to the southern Sierra Nevada region.

The six GCM-based scenarios are: (1) HadCM2 2010-2039; (2) HadCM2 2050-2079; (3) HadCM2 2080-2100; (4) NCAR PCM 2010-2039; (5) NCAR PCM 2030-2059; (6) NCAR PCM 2080-2100. The six incremental scenarios are: (1) 1.5oC temperature increase, 0.0 % precipitation change; (2) 1.5oC temperature increase, 9.0 % precipitation change; (3) 3.0oC temperature increase, 0.00 % precipitation change; (4) 3.0oC temperature increase, 18.0 % precipitation change; (5) 5.0oC temperature increase, 0.00 % precipitation change; (6) 5.0oC temperature increase, 30.0 % precipitation change.

Sets of mean-monthly climatological streamflow response as a function of climate change precipitation ratios and temperature differences are presented. Shifts in maximum streamflow amounts and the range of differences from the sets of calculations are discussed. Streamflow uncertainty and likelihood of extreme events (very wet, very dry) are also discussed.

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