p recipitation extremes during 1895-2003 in the continental united states kenneth e. kunkel illinois...
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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
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