hydrology and water management applications of gcip research
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Hydrology and Water Management Applications of GCIP Research
Dennis P. LettenmaierDepartment of Civil and Environmental Engineering
University of Washington
for presentation at
Stakeholder SessionMississippi River Climate and Hydrology Conference
New OrleansMay 14, 2002
GEWEX and GCIP Goals
Scientific goal: “To observe and model the hydrologic cycle and energy fluxes in the atmosphere, and at the land and ocean surface”
Applications goal: “Demonstrate skill in predicting changes in water resources on time scales up to seasonal, annual and interannual”
GCIP Contributions for Water Management
• Data sets
• Macroscale land surface model development and improvements
• Land Data Assimilation System (LDAS)
• Forecast method and product development
Data Sets
Many, key examples include:• WSR-88d retrospective archive (1996-
2000)• GOES solar radiation• LDAS retrospective (model forcing, e.g.,
precipitation, and model-derived, e.g., soil moisture)
• LDAS real time
LDAS Modeling Domain
Domain is North America between 25º and 53º N
Resolution 1/8º
77,000 grid cells through domain (56,000 in Continental U.S.)
Model developed for 15 sub-regions
Model forcing data (1949-2000) derived from observations
Run at a 3-hour time step
LDAS Derived Soil Moisture - Active Range
50-Year Soil Moisture Range Scaled by Annual Precipitation
•Long term spatial data set allows characterization of variability
•Dynamic range of the soil column
•Degree to which source of variability (P) is buffered by soil column
•Level of hydrologic interaction of soil column
Macroscale land surface model development and improvements
VIC Hydrologic Model
Land Data Assimilation System (LDAS)
LDAS land surface model (LSM) and coupled model interaction
LDAS real-time soil moisture
Forecast method and product development
Coupled GCM
Embedded Regional
CMSST
Forecast
Macro-Scale Hydrology
Model (VIC)
How NCEP makes experimental ensemble climate forecasts
Initial and PredictedSST for next6 months
We use the raw model output at this point.
…but, we must recognize the scale mismatch
20 differentInitial statesof the atmosphere
20 unique forecasts of the climate over the next six months
2x2 degree AGCM
Coupled Ocean-AGCM
PROB PROB
GSM PCP OBS PCP
RAW FORECAST PCP BIAS-CORR PCP
East Coast
Apr ’00 forecast for May-Jun-Jul
forecast median shown as percentile of climatology ensemble
CRB May forecasthindcast “observed”forecast
forecastmedians
CRBMay Forecast
cumulative flow averages
forecastmedians
Information Xfer to Stakeholders: How well did GCIP succeed in
“demonstrating skill”?
Conclusion: Quite well, if the goal is taken literally
but
Demonstrated use of GCIP “products” by water managers is minimal
why?
• Scientists are not particularly skilled, or even interested in, “technology transfer”
• Practitioners are stuck in “paradigm lock”; institutional inertia on algorithms and methods
• GCIP/GAPP has provided science, not applications funding -- focus on many small projects of limited duration discourages long-term view
• Possible solution: better liaison with RISAs as mechanism for breaking “paradigm lock”
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