“Science exists to serve human welfare. It’s wonderful to have the opportunity given us by society to do basic research, but in return, we have a very important moral responsibility to apply that research to benefiting humanity.”

Dr. Walter Orr Roberts (NCAR founder)

David Yates, National Center for Atmospheric Research Boulder, Colorado

David Yates, National Center for Atmospheric Research Boulder, Colorado

American Rivers, 28 Jan 2010

From Climate Models to Water Decision Making in the Hydrologic Sciences

NCAR Scientific facilities

2. Supercomputers, data and networks

3. International Collaborative Research Environment

National Science Foundation Research & Development Center- 900 Staff, 500 Scientists/Engineers- Basic Research & Societal Applications- Atmospheric and related sciences

1. Advanced Observational Facilities

NCAR

The World Has Warmed‐

Observations

Globally averaged, the planet is about 0.75°C warmer than 

it was in 1860.

NCAR

2005 was the hottest year on record;   the 13 

hottest all occurred since 1990, 23 out of the 

24 hottest since 1980.

J. Hansen et al., PNAS 103: 14288‐293 (26 Sept 2006)

Green bars show 95% 

confidence intervals

Global surface temperature since 1880

°C

Global Climate Models

The Hadley cells are the main way the atmosphere transports energy polewards in low latitudes

UCAR Confidential and Proprietary © 2008 University Corporation for Atmospheric

A grid of points over EarthLayers

Typical global climate model has 1-2 million calculation points

Timeline of Climate Model Development

Climate of the last Millennium

Caspar AmmannNCAR/CGD

Abrupt Transitions in the Summer Sea Ice

ObservationsSimulated5-year running mean

• Gradual forcing results in abrupt Sept ice decrease

•

Extent decreases from 80 to 20% coverage in 10 years.

“Abrupt”transition

Simulation of Future Climate

The Precip The Precip ChallengeChallenge

80 yr. Temp. Rise

CMIP80 yr.

Precipitation Trend ?

Covey et al. 2003

Diurnal Cycle of Convective Precipitation for JJA

Observed Frequency 1976-97Time of maximum

CCSM Frequency 1983-88Time of maximum

Modeled frequency occurs about 2 hours earlier than observedDai and Trenberth 2003

2 km 4 km 10 km 20 km

Why Do We Care about Precip. Characteristics?

Dry Soils

Surfa

ce F

lux (

mm

/hr)

6 12 18 240

P

R

E

P

R

E

Great Plains Colorado

Wet SoilsHour

Importance of Diurnal Timing

Daily Precipitation at 2 stationsDaily Precipitation at 2 stations

0

20

40

1 6 11 16 21 26

0

20

40

1 6 11 16 21 26

Frequency 6.7%Intensity 37.5 mm

Frequency 67%Intensity 3.75 mm

MonthlyAmount 75 mm

Amount 75 mm

drought wild fires localwilting plants floods

soil moisture replenishedvirtually no runoff

A

B

NCAR

Global models in 5-10 yrs?

Climate Models circa early 1990s Global coupled climate models in 2006

Regional models

NCAR

Water Res Fnd-NCAR

AwwaRF-NCAR Climate Change Primer

Develop structured process to explicitly consider CC into decision making

Work with partnering utilities from the very start

ÑÑÑ

Ñ

Ñ

CABY CoSpgs MWRA

Durham

PalmBeach

• Inland Empire of Southern California• Regional Utility Alliance in California, CABY• Colorado Springs, CO• Boston, MA• Durham, NC• Palm Beach County, FL• New York City, NY• Portland, OR

NYC

IEUA

NCAR

Partnership Design and Decision Tools

Industry Research – AwwaRF

Climate Research – NCAR; Universities; Federal Agencies

Project Team

NCAR, consultants

Utility Partners

Structured Process & Decision Tools

NCAR

Decision Analysis Approach

UncertaintyAnalysis

Evaluation of Alternatives

Represent keyvariables withprobabilities;Determine bestplan under uncertainty

iterations

We Really want to Support Decision Making

ProblemStructuring

DeterministicAnalysis

Goals, alternatives,information, values

Modelof the decision;Sensitivity analysis toidentify keyvariables

NCAR

The Regional CABY Model in WEAP

NCAR

2020-2024

1996-2000Upper Rubicon Streamflow

NCAR

Water Temperature

0

5

10

15

20

Wk 4

0W

k 43

Wk 4

6W

k 49

Wk 5

2W

k 3W

k 6W

k 9W

k 12

Wk 1

5W

k 18

Wk 2

1W

k 24

Wk 2

7W

k 30

Wk 3

3W

k 36

Wk 3

9

C

Historic DT2

Reservoir Storage

2000025000300003500040000450005000055000600006500070000

Wk

40

Wk

43

Wk

46

Wk

49

Wk

52

Wk

3

Wk

6

Wk

9

Wk

12

Wk

15

Wk

18

Wk

21

Wk

24

Wk

27

Wk

30

Wk

33

Wk

36

Wk

39

Acr

e-Fe

et

HistStorage DT2

Reservoir Storage

Water Temperature

NCAR

Thanks

http://www.isse.ucar.edu/awwarf/http://www.awwarf.org

http://sei-us.orghttp://weap21.org

David Yates yates@ucar.edu