Precipitation Intensity Climate Impacts Group & Department of Atmospheric Sciences University of...

Precipitation IntensityPrecipitation Intensity

Climate Impacts Group&

Department of Atmospheric SciencesUniversity of Washington

Eric Salathé

Climate Change: North America

Annual SummerWinter

Climate Change: Pacific Northwest Precipitation

-25.00

-20.00

-15.00

-10.00

-5.00

0.00

5.00

10.00

15.00

J F M A M J J A S O N D

SRES A1B 2020s

SRES A1B 2040s

SRES A1B 2080s

Pre

cip

itatio

n C

ha

ng

e (

%)

Change in U.S. PNW precipitation by monthfrom 1990s to futuresimulated by 20 climate models

Consensus of current Global Climate Models: Intensification of Mid-latitude storms Less frequent storms Northward shift in storm track

Changes in Pacific Storm Track

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

Shift in Pacific Storm Track J Yin, Geophys Res Lett, 2005

S Pole S PoleN Pole N PoleEQ EQ

Temperature Change 1980-2000 to 2080-2100

Change in Storm Growth

Shift in Pacific Storm Track

Salathé, Geophys Res Lett, 2006

Observed (NCEP-NCAR Reanalysis)

20th Century Model Composite

21st Century Model Composite

1950-2000 to 2050-2100 Nov-Dec-Jan

Shift in Aleutian Low


Observed

20th Century Model Composite

1950-2000 to 2050-2100 Nov-Dec-Jan

Movement of Jetstream

1950s


1960s


1970s


1980s


1990s


1950s

Are extreme rain events becoming more frequent?

Valérie Dulière, Philip Mote, Eric Salathé, Josiah Mault and Marketa McGuire Elsner

(Climate Impacts Group, University of Washington)

2008 Pacific Northwest Weather Workshop

Source : THE OREGONIAN/Bruce Ely


The Chehalis River flooding

The Centralia station


Distribution function of daily precipitationsfrom 1948 to 2006

10 cm5 cm


Distribution function of daily precipitationsfrom 1948 to 2006 (Zoom)

10 cm5 cm

19901990

2001

2006

1996

1986

1951, 1981

1986

1994, 1986



10 cm5 cm

19901990

2001

2006

1996

1986

1951, 1981

1986

1994, 1986

Since 1948, 80% of the 20 greatest extreme daily rain events occurred after 1985!



10 cm5 cm

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

1.00 10.00 100.00

Return Period, Tr (1/p)

Annual Peak Precip (in)

Return period of annual maximum daily precipitation

--1948-1976--1977-2006


2.5 yr

3.3 in


The Past 50 Years

The Cooperative Observer Program network

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

1.00 10.00 100.00

Return Period, Tr (1/p)

Annual Peak Precip (in)

Return period of annual maximum daily precipitation

--1948-1976--1977-2006


10-year Return

} Percent Change

(P2-P1)/P1*100Return period = 10 years

-40

-30

-20

-10

0

10

20

30

40

50

60

1

Climate Division

Percentage of change

Stations

Average

1 2 3 4 5 6 7 8 9 10

Percentages of change in the annual maximum daily precipitation with a 10 years return period for each station

1 2 3 4 5 6 7 8 9 10

What Do Climate Models Project for the Future?


Projected Future Changes from Climate Models(2046-2065 versus 1981-2000)

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

-20

-10

0

10

20

30

40

50

60

70

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Grid cell


-30

-20

-10

0

10

20

30

40

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Grid cell


IPSL

SRES A1B SRES B1

Percentages of change in the annual maximum daily precipitation with a 10 years return period for each grid cell between 1981-2000 and 2046-

2065.

ECHAM5

CCSM3


-20

-10

0

10

20

30

40

50

60

70

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Grid cell


-30

-20

-10

0

10

20

30

40

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Grid cell


IPSL

SRES A1B SRES B1


2065.

+18.8% +11.8%

ECHAM5

CCSM3


-20

-10

0

10

20

30

40

50

60

70

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Grid cell


-30

-20

-10

0

10

20

30

40

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Grid cell


IPSL

-20

-10

0

10

20

30

40

50

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47

Grid cell


-5

0

5

10

15

20

25

30

35

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47

Grid cell


ECHAM5

SRES A1B SRES B1


2065.

+18.8%

+11.4%

+11.8%

+10.6%

CCSM3


-20

-10

0

10

20

30

40

50

60

70

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Grid cell


-30

-20

-10

0

10

20

30

40

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Grid cell


IPSL

-20

-10

0

10

20

30

40

50

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47

Grid cell


-5

0

5

10

15

20

25

30

35

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47

Grid cell


ECHAM5

SRES A1B SRES B1

-20

-10

0

10

20

30

40

50

60

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76 79 82 85 88

Grid cell


CCSM3

-20

-10

0

10

20

30

40

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76 79 82 85 88

Grid cell



2065.

+12.2%

+18.8%

+11.4%

+10.8%

+11.8%

+10.6%


0

5

10

15

20

25

30

35

40

IPSL ECHAM5 CCSM3

20c

sresa1b

sresb1

Num

ber

of

days

per

ye

ar

Number of days per year with

P > 0.4 inches


0

5

10

15

20

25

30

35

40

IPSL ECHAM5 CCSM3

20c

sresa1b

sresb1

0

0.01

0.02

0.03

0.04

0.05

0.06

IPSL ECHAM5 CCSM3

20c

sresa1b

sresb1

Num

ber

of

days

per

ye

ar


P > 0.4 inches P > 1.6 inches


P > 0.4 inches P > 1.6 inches P > 2.8 inches

0

5

10

15

20

25

30

35

40

IPSL ECHAM5 CCSM3

20c

sresa1b

sresb1

0

0.01

0.02

0.03

0.04

0.05

0.06

IPSL ECHAM5 CCSM3

sresa1b

sresb1

20c

0.0000

0.0005

0.0010

0.0015

0.0020

0.0025

0.0030

0.0035

IPSL ECHAM5 CCSM3

20c

sresa1b

sresb1

Num

ber

of

days

per

ye

arProjected Future Changes from Climate Models

(2046-2065 versus 1981-2000)

GOING TO THE EXTREMES

GOING TO THE EXTREMES AN INTERCOMPARISON OF MODEL-SIMULATED

HISTORICAL AND FUTURE CHANGES IN EXTREME EVENTS CLAUDIA TEBALDI ,

KATHARINE HAYHOE, JULIE M. ARBLASTER and GERALD A. MEEHL, Climatic

Change (2006) 79: 185-211

9 Global Model Simulations for IPCC

1. Number of days with precipitation greater than 10 mm (precip > 10).

2. Maximum number of consecutive dry days (dry days).

3. Maximum 5-day precipitation total (5 day precip).

4. Simple daily intensity index, defined as the annual total precipitation divided by the number of

wet days (precip intensity).

5. Fraction of total precipitation due to events exceeding the 95th percentile of the climatological

distribution for wet day amounts ( precip > 95th).

Going to Extremes

Mesoscale Effects

Global models do not resolve fine-scale processessuch as topographic precipitation

Downscaling methods are used to account forregional effects

Statistical downscaling uses observed relationshipbetween large-scale and fine-scale patternsto extrapolate to climate model results

Regional climate model simulates fine-scale physical processes

Change in Orographic Enhancement


Downscaling without wind effect

1990-2000 to 2045-2055 Sept-Oct-Nov

Downscaling with wind effect

Mesoscale Climate Model Based on Regional Weather Model (MM5, WRF)

Nested grids 135-45-15 km

Advanced land-surface model (NOAH) with interactive deep soil

temperature

Global Climate Model used as Input (boundary conditions)

Autumn Precipitation Changes

mm per day

Change in Autumn precipitation rate from 1990s to 2050sas simulated in regional climate model

WindsShift toOnshore

Rain increases along mountain ridge

Change in Orographic Enhancement

MM5 vs Statistical Downscaling

Statistical DownscalingP only P & Wind MM5

Change in November Precip (mm/day) 1990s to 2050s

Conclusions :

-This is the beginning of our work.

- According to the observations from the COOP network, extreme rain events have globally increased in frequency and intensity between 1948-1976 and 1977-2006 over the Washington state.

- According to global climate models (IPSL, ECHAM5 and CCSM3), extreme rain events will in average be more intense and more frequent in 2046-2065 than now, over the PNW region.

Coming next :

Analysis of output from regional climate models.

Source : http://www.earthcam.com/

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