Precipitation extremes during 1895-2003 in the continental

United StatesKenneth E. Kunkel

Illinois State Water SurveyCollaborators: Dave Easterling, Kelly

Redmond, Ken Hubbard, Connie Woodhouse, Ed Cook

Questions

• Are the frequency and intensity of extremes changing?

• What is the magnitude of natural variability in the frequency and intensity of extremes

• What are the implications for the global change debate?

• Trends in extreme precipitation• Characteristics of early 20th Century pluvial• Causes of observed trends

U.S. Climate Data

• U.S. Cooperative Observer Network in operation since late 1880s

• Daily Observations – Max and Min Temp, Precip, Snowfall, Snow Depth

• Digitizing of Observations began in 1948• Miscellaneous projects resulted in the

digitizing of selected data prior to 1948

Until recently, digital availability of pre-1948 daily

climate data has been deficient

Climate Database Modernization Project

• U.S. Congress has appropriated funds to NOAA NESDIS to digitize data records

• One of the first data sets chosen for digitization was the daily cooperative records. Digitization of these records finished for the most part in 2001.

Daily Precipitaiton in TD3200, TD3205, and TD3206

TD3206 TD3200+TD3205

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

1890 1910 1930 1950 1970 1990

Year

Num

ber

of S

tatio

ns

Long-term Stations: 1895-2003

Red – new; Blue - old

Data Set Quality Control

• Basic QC of data performed by National Climatic Data Center

• A collaborative project, partially funded by NOAA OGP CCDD, to more completely QC these data has been completed

• Illinois State Water Survey, National Climatic Data Center (Dave Easterling), U. of Nebraska-Lincoln (Ken Hubbard), Desert Research Institute (Kelly Redmond)

Extremes Definition

• Event Duration – days• Recurrence (threshold exceedance) –years• 1,5,10,30-day duration• 1,5,20-year recurrence• National index

-60

-40

-20

0

20

40

60

1895 1910 1925 1940 1955 1970 1985 2000

Year

EPI A

nom

aly

(%)

1-yr 5-yr 20-yr

1-day duration

-60

-40

-20

0

20

40

60

1895 1910 1925 1940 1955 1970 1985 2000

Year

EPI A

nom

aly

(%)

1d1y1d5y1d20y5d1y5d5y5d20y10d1y10d5y10d20y30d5y30d20y

1-dy,1-yr Extreme Precipitation: 1895-1905

Blue = positive anomaly Red = negative anomaly

1-dy, 1-yr Extreme Precipitation: 1990-2000

Blue = positive anomaly Red = negative anomaly

Winter

-30

-20

-10

0

10

20

30

1895 1910 1925 1940 1955 1970 1985 2000

Year

EPI A

nom

aly

(%)

1d1y1d5y1d20y5d1y5d5y5d20y10d1y10d5y10d20y30d5y30d20y

Spring

-30

-20

-10

0

10

20

30

1895 1910 1925 1940 1955 1970 1985 2000

Year

EPI A

nom

aly

(%)

1d1y1d5y1d20y5d1y5d5y5d20y10d1y10d5y10d20y30d5y30d20y

Summer

-30

-20

-10

0

10

20

30

1895 1910 1925 1940 1955 1970 1985 2000

Year

EPI A

nom

aly

(%)

1d1y1d5y1d20y5d1y5d5y5d20y10d1y10d5y10d20y30d5y30d20y

Fall

-30

-20

-10

0

10

20

30

1895 1910 1925 1940 1955 1970 1985 2000

Year

EPI A

nom

aly

(%)

1d1y1d5y1d20y5d1y5d5y5d20y10d1y10d5y10d20y30d5y30d20y

Current Drought in West

• High frequencies in western U.S. occurred shortly before 1922 Colorado River compact

• Analysis of this period reveals role of extreme seasons

• Compact based on 16.5 maf annual flow; 1906-2001 average was 15.1 maf; paleoclimatic reconstructions indicate 400-year average of only 13.5 maf

West

340

360

380

400

420

440

460

1895 1910 1925 1940 1955 1970 1985 2000

Year

Prec

ipita

tion

(mm

)

Total

Tree ring reconstruction

• Tree-ring reconstruction of western US climate recently extended back to more than 1000 years before present (Cook et al, Science, in press)

• Comparative analysis tree-ring reconstruction for early 20th Century pluvial (consecutive years of positive PDSI, cumulative PDSI sum) – Connie Woodhouse, Dave Easterling, Ed Cook

# of years period cumulative sum average annual value

99877

1076-10841112-11201424-14311615-16211911-1917

12.86 8.99 6.4611.5112.22

1.1291.0000.8071.6451.750

Western United States Tree-Ring Climate Reconstruction

Consecutive Years of Positive Palmer Drought Severity Index

West (5-day periods)

-60

-40

-20

0

20

40

60

1895 1910 1925 1940 1955 1970 1985 2000

Year

Prec

ipita

tion

Dep

artu

re fr

om N

orm

al (m

m)

Total0-1212-2525-50>50

West

-30

-20

-10

0

10

20

30

1895 1910 1925 1940 1955 1970 1985 2000

Year

Prec

ipita

tion

Dep

artu

re fr

om N

orm

al (m

m)

Winter Spring Summer Fall

West

0

25

50

75

100

125

150

175

200

225

250

1880 1900 1920 1940 1960 1980 2000 2020

Year

Prec

ipita

tion

(mm

)

Winter Spring Summer Fall

season precipitation (mm)

*winter 1908-09winter 1968-69winter 1939-40spring 1995*winter 1915-16*winter 1913-14*winter 1914-15winter 1997-98winter 1995-96*spring 1906winter 1940-41winter 1979-80*winter 1910-11*winter 1905-06winter 1935-36

209201196189182182182181180178178177176176175

Wettest Seasons in Western U.S.

Causes

• Studies with GISS GCM• North Pacific Index• Cyclone tracksKlein, W. H., 1957: Principal tracks and mean frequencies of cyclones and

anticyclones in the Northern Hemisphere. U.S. Weather Bureau Research Paper 40, 60 pp.

U.S. Weather Bureau, Daily Synoptic Series, Historical Weather Maps, Northern Hemisphere Sea Level, January 1899 to June 1939, Cooperative project of U.S. Army Air Force and U.S. Weather Bureau, Washington DC 1944.

November-March North Pacific Index

-6

-4

-2

0

2

4

6

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

Year

NPI

0

2

4

6

8

10

12

14

16

18

1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

Year

Cycl

one

Freq

uenc

y

CONCLUSIONS

• Heavy Precipitation Frequencies were highest during the late 20th Century but also rather high during the late 19th and early 20th Century

• The late 20th Century peak may be caused by Tropical Pacific SST anomalies. The early 20th Century peak occurs at a time of large positive values of the NPI and above normal frequency of cyclones coming ashore in the Pacific Northwest.

Atlantic Multi-decadal Oscillation

-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990

Year

AM

O

THE END