410 likes | 552 Views
Seasonal outlooks for hydrology and water resources in the Pacific Northwest. Andy Wood Alan Hamlet Dennis P. Lettenmaier Department of Civil and Environmental Engineering for Climate and Water Resource Forecasts for the 2006 Water Year UW Climate Impacts Group October 26, 2005, Seattle.
E N D
Seasonal outlooks for hydrology and water resources in the Pacific Northwest Andy Wood Alan Hamlet Dennis P. Lettenmaier Department of Civil and Environmental Engineering for Climate and Water Resource Forecasts for the 2006 Water Year UW Climate Impacts Group October 26, 2005, Seattle
Presentation Outline 1. Introduction: UW Experimental Hydrologic Forecasting System 2. Water Year 2005 Assessment 3. Water Year 2006 Outlook
PNW Introduction: A review of the PNW hydrologic cycle • soil moisture near annual low • runoff near low • nearly all water year precipitation yet to come • snow season not really underway • evaporation not a factor Average annual water cycle Where we are now on average
Experimental W. US Hydrologic Forecast System Snowpack Initial Condition Soil Moisture Initial Condition
Experimental W. US Hydrologic Forecast System Multiple Seasonal Climate Forecast Data Sources CCA NOAA CAS OCN CPC Official Outlooks SMLR CA Coupled Forecast System VIC Hydrology Model NASA NSIPP/GMAO dynamical model ESP ENSO UW ENSO/PDO
recently observed meteorological data ensemble of met. data to generate forecast ESP forecast Spin-up ICs Forecast obs hydrologic state Hydrologic prediction using ESP • NWS River Forecast Center (RFC) approach: • rainfall-runoff modeling • (i.e., NWS River Forecast System, • Anderson, 1973 • offspring of Stanford Watershed Model, Crawford & Linsley, 1966) • Ensemble Streamflow Prediction(ESP) • used for shorter lead predictions; • increasingly used for longer lead predictions
monthly hydrographs targeted statistics e.g., runoff volumes spatial forecast maps
Presentation Outline 1. Introduction: UW Experimental Hydrologic Forecasting System 2. Water Year 2005 Assessment 3. Water Year 2006 Outlook
LAST YEAR Oct. 1 Soil Moisture Comparison THIS YEAR
Winter 2004-05:seasonal volume forecast for APR-SEP flow ESP median, 10th & 90th %-iles ESP-ENSO (warm) median OBS Forecasts made on 1st of Month
Winter 2004-05:seasonal volume forecast for APR-SEP flow ESP median, 10th & 90th %-iles ESP-ENSO (warm) median OBS Forecasts made on 1st of Month
Winter 2004-05:seasonal volume forecast for APR-SEP flow ESP median, 10th & 90th %-iles ESP-ENSO (warm) median OBS Forecasts made on 1st of Month
Winter 2004-05:seasonal volume forecast for APR-SEP flow ESP median, 10th & 90th %-iles ESP-ENSO (warm) median OBS Forecasts made on 1st of Month
Winter 2004-05:seasonal volume forecast for APR-SEP flow ESP median, 10th & 90th %-iles ESP-ENSO (warm) median OBS Forecasts made on 1st of Month
Presentation Outline 1. Introduction: UW Experimental Hydrologic Forecasting System 2. Water Year 2005 Assessment 3. Water Year 2006 Outlook
Basin Average Water Balance Perspective Averaging water balance variables over a region can help characterize the evolution of the water year forecast distribution max 0.75 median 0.25 min spinup
Oct 1 ESP fcst: WY2006 Precip, Temp Temp Precip 2005 2006 2005 2006 Columbia R. basin upstream of The Dalles, OR
hangover from last year’s soil moisture deficit Oct 1 ESP fcst: WY2006 SM, SWE, RO Soil Moist Runoff Apr-Sep % of avg ESP: 98% ENSO: 95% 2005 2006 SWE
Oct 1 ESP fcst: WY2006 Precip, Temp Temp Precip 2005 2006 2005 2006 Puget Sound Drainage Basin
Oct 1 ESP fcst: WY2006 SM, SWE, RO Runoff Soil Moist 2005 2006 SWE Apr-Sep % of avg ESP: 98% ENSO: 96%
Oct 1 ESP fcst: WY2006 Precip, Temp Precip Temp 2005 2006 2005 2006 Yakima R. Basin near Parker, WA
Oct 1 ESP fcst: WY2006 SM, SWE, RO Soil Moist Runoff 2005 2006 SWE Apr-Sep % of avg ESP: 93% ENSO: 90%
Oct 1 ESP fcst: WY2006 Precip, Temp Temp Precip 2005 2006 2005 2006 BC portion of Columbia R. Basin
Oct 1 ESP fcst: WY2006 SM, SWE, RO Soil Moist Runoff 2005 2006 SWE Apr-Sep % of avg ESP: 101% ENSO: 99%
Conclusions • It’s still early in year for hydrologic forecasts, especially in an ENSO neutral year • Most PNW basins have land surface tendency for being on dry side by 3-10 percent: • exceptions: south edge of Snake R. basin, also BC • The parts of the region that receive higher rainfall (west of the Cascades) are more likely to recover from moisture deficits from last year.
Questions? website: www.hydro.washington.edu / forecast / westwide /
Seasonal Climate Prediction e.g., precipitation
3/15 ESP fcst: WY2006 vs. WY1977 Precip, Temp Snake River basin