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”