Transcript Long Range Ensemble Streamflow Prediction

Western Water Supply
Kevin Werner, Andrew Murray, WR/SSD
Jay Breidenbach, WFO Boise
Cass Goodman, Steve Shumate, CBRFC
Alan Takamoto, Scott Staggs, CNRFC
Don Laurine, NWRFC
Chad Kahler, WFO Tucson
Outline
 Western Water Supply
 History
 Project overview
 Westwide map
 Forecast evolution
 Verification
 Ensemble services
 Future enhancements
 Climate variability and change
 Short range ensembles services
Western Water Supply Forecasts
 Forecasts for spring runoff
amounts from snow melt
dominated basins in western
US
 Routinely produced at 6 RFCs
and coordinated with other
agencies (NRCS and
California DWR)
 NWS forecast program began
in 1940s
 Primary forecast tools:
 Ensemble Streamflow
Prediction
 Multivariate Linear
Regression
Legacy Water Supply Forecast
Product (Credit: NRCS / NOAA)
Project in a Nutshell

Goals:
 A “one stop shop” for NWS water information at the seasonal timescale
 Consistent presentation of products between RFCs
 Harness collective innovation from multiple offices

Users:
 Existing Water Supply forecast users
 Strong support from USBR and state water resources agencies for
examples
 Groups with cross basin interests (e.g. media, power companies)
 NWS internal users

Major Components:
 Map: Single map for all western WS forecasts from 6 RFCs
 Forecast evolution: Plotting capability to show evolution of current year
forecast and observed river flow
 Verification: Forecast evaluation from past forecasts and forecast tools
 Ensemble services: Interaction capability with ensemble streamflow
predication
Project in a Nutshell (con’t)
 Milestones (past):
 April 2005: Working group formed, planning meeting held
 January 2006: Initial website launched
 September 2006: Included AB, WG, and MB RFCs in development
 January 2007: Common database developed
 March 2007: Launched outreach effort and included SHs
 Milestones (future):
 August 2007: Launch verification 1.0 capabilities
 September 2007: Move software to NWRFC web farm
 October 2007: Launch forecast evolution 2.0
 October 2007: Launch ensemble services 1.0
 January 2008: Integrate WGRFC data
 2008?: Integrate climate change capabilities
Map

www.cbrfc.noaa.gov/westernwater

“One Stop Shop” for NWS water
supply forecasts

Flexible and consistent map
presence across western USA

Zoomable to basin scale

Mouse over capability for forecast
values
Forecast Evolution

Evolution of current year forecast
and observed streamflow

Options to include:
 Normal streamflow volume
 Forecast window
 Forecast accumulation
 Accumulated Observed, etc…

Originally developed at NWRFC

Version 2.0 contract development
work proceeding
 Add ESP forecasts
 Add interactive features
Forecast Verification
 Goal: Provide users of all types with forecast verification information
 Easy to understand
 Meaningful
 Accessible from forecasts
 Dynamically generated plots from database
Data Visualization
Error
 MAE, RMSE, etc
 Conditional on
Lead time, year
Skill
Categorical
 Skill relative to
Climatology
Traditional (NWS) verification including FAR
and POD
 Conditional
 Category definitions tied to climatology
values (e.g. mean flow, terciles, etc.) or user
definable
Plot credit: Chad Kahler
Ensemble Services
 Goals:
 Intuitive user interface for current ensemble forecast
 Access to archived streamflow data for perspective
 Dynamic, flexible plots
 Access to underlying data and database
 Climate change scenarios
Climate Change
 Latest IPCC report confirms
“temperatures averaged over
all habitable continents … will
very likely rise at greater than
the global average rate in the
next 50 years and by an
amount substantially in excess
of natural variability.” (IPCC
WR1, 2007)
Source: IPCC, 2007
Trends in 1 Apr SWE over the 1960–2002 (left) and 1950-1997
(right) periods of record directly from snow course observations
from Mote (2006) and Mote et al. (2005) respectively.
Extend NWS Product Suite?
Years
Climate Change
based run off
scenarios?
 Current product suite covers hours to seasons;
 Should we consider climate change scenarios and build
multi-year products for run-off, temperature, precipitation?
 User requirements from power companies, USBR, etc for
climate change scenarios
Water Supply with
Climate Change
 Many in water community are asking for it
 Idea: Provide scenario based water supply outlooks in the context of
historical data and current season forecasts
 Include uncertainty
 Temperature, precipitation, and/or lead time based scenarios
 Ultimately link scenarios to atmospheric carbon based scenarios
 Leverage historical simulation capabilities in ESP
Leveraging ESP for long range scenarios
 Multiple “historical simulation” runs:
 Use historical basin temperature and precipitation time series
 Build ensemble by repeatedly shifting year order by one
 Incorporate scenarios through additive (temperature) or
multiplicative (precipitation) year-wise adjustments
ENSEMBLE FORECAST SERVICES
Forecast Point: Columbia River at the Dalles Dam
Archive
Current Forecast
Climate Change
Options
O Normal Runoff
O Ensemble Streamflow
Prediction O Ensemble
members by forcing
year(s)
O Year (slider bar 20102050)
O Accumulate over
period
O Temperature (slider
bar -5 F - +5 F)
O Plot Type (box and
whisker, bar, lines, etc.)
O Carbon Scenario
O Data
O Model Normal
O Historical Year(s)
O Ensemble members
by ENSO
O Plot interval (set axes
limits)
Summary
 Western Water Supply
 History
 Current capabilities
 Coming enhancements
 Verification
 Water Supply ensemble services
 Climate Change
Thank You
[email protected]