Director National Climatic Data Center A Perspective on Understanding Changes in Weather and Climate Extremes Plant Sector Workshop March 21 2012 Outline Motivation Billiondollar Disasters ID: 504760
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Slide1
Thomas R. KarlDirector, National Climatic Data Center
A Perspective on Understanding Changes in Weather and Climate Extremes
Plant Sector WorkshopMarch 21, 2012Slide2
OutlineMotivationBillion-dollar DisastersState of the ScienceHeat and Cold WavesPrecipitation/flooding and droughtSnowstormsTornadoesSummary2Slide3
Billion-Dollar Weather and Climate Disasters 20113Three more in 2011 approaching $1BLate-October Northeast winter storm
April 19-20 Midwest and Southeast tornadoesAugust 18-21 Midwest and East high wind & hail
NOAA/NCDCSlide4
Billion-Dollar Weather and Climate DisastersSince 1980, 114 billion-dollar weather and climate disasters in U.S.Total losses since 1980 of billion-dollar disasters exceed $800 billion.Is the U.S. becoming more exposed and/or sensitive to severe events?A Record 14 Disasters in the U.S. in 2011
Three more approaching $1B4
NOAA Billion-Dollar Disasters http://www.ncdc.noaa.gov/oa/reports/billionz.htmlSlide5
5Status of Present Knowledge Monitoring and Understanding Changes in Extreme Storm Statistics: State of Knowledge - Kunkel, K.E. et al. (23 others). In Review (BAMS
).Monitoring and Understanding Changes in Heat Waves, Cold Waves, Floods and Droughts in the United States: State of Knowledge - Peterson, T.C. et al. (27 others). In Review (BAMS).
Monitoring and Understanding Changes in Extreme Winds, Waves, and Extratropical Storms along the Coasts: State of Knowledge - Vose, R.S. et al. (25 others) To be submitted (BAMS).Slide6
6Status of Present Knowledge Slide7
Heat Waves/Cold Waves in the U.S.(Observations)7
Extremes in Maximum TemperatureExtremes in
Minimum Temperature
Percent of the U.S. with much above
or
below
normal temperature
NOAA U.S. Climate Extremes Index
http
://www.ncdc.noaa.gov/extremes/cei/Slide8
U.S. Annual Maximum & Minimum Temperatures8Minimum Temperature: statistically significant increase (0.05; 0.01 nearly)
Minimum Temperature: statistically significant decrease (0.001)
Percent of the U.S. much above normal
Percent of the U.S. much below normal
Maximum Temperature: not statistically significant
Maximum Temperature: statistically significant
decrease (0.05) (0.01 nearly)
Katz, R. W., Unpublished results, 2012.Slide9
Heat and Cold Waves(Mean Daily Temperature)Coldest air masses in North American source regions are warming on multi-decadal timescales (Kalkstein et al. 1990; Hankes and Walsh 2011)Depending on the index used, differing conclusions about sub-continental statistical significance of change in heat/cold extremes
9Decadal average values of heat waves (red bars)
and cold waves (blue bars) indices for spells of 4-day duration exceeding the threshold for a 1-in-5-year recurrence.
Adapted from
Peterson, T.C.
et al
., 2012 (In Review).
Monitoring and Understanding Changes
in Heat Waves, Cold Waves, Floods and Droughts in the United States:
State of Knowledge.
BAMS
.Slide10
“Normalized” Temperature DistributionNorthern Hemisphere Land - Jun-Jul-Aug (1951-1980 Base Period)10Hansen, J. et al., 2012 (submitted). Public Perception of Climate Change and the New Climate Dice. Proceedings of the National Academy of Science.
“Normalized” DeparturesSlide11
1-Day Heavy Precipitation Events11Percent of the U.S. with much above normal 1-day heavy precipitation (>50.8mm)
Annual (Jan-Dec) 1910-2011
A statistically significant increase in extremes
NOAA U.S. Climate Extremes Index
http
://www.ncdc.noaa.gov/extremes/cei/Slide12
Extreme Precipitation12Differences between two periods (1990-2009 minus 1971-1989) for daily, 1-in-5yr extreme events and coincident (spatial and temporal) precipitable water values
Extreme Precipitation Frequency Index Difference
(Percent)
Precipitable Water Difference
(Percent)
Adapted from Kunkel
, K.E. et al
., 2012 (In Review). Monitoring
and Understanding Changes in Extreme Storm Statistics: State of
Knowledge.
BAMS
.
All changes positiveSlide13
Flooding and Precipitation13
Regional similarities between trends of annual precipitation, droughts, and extremes of river flooding
Regional similarities between extremes of river flooding and extremes of precipitation is not as congruent
River-Flow Trends in Annual Maximum
Trends in Total Annual Precipitation: 1909-2008
Difference in Number of Months with
Moderate to Extreme Drought
85-127
years
ending 2008
85-127
years
ending 2008
Peterson, T. C. et
al
., 2012 (In Review). Monitoring
and Understanding Changes in
Heat Waves, Cold Waves, Floods and Drought in the United States:
State of
Knowledge.
BAMS
.Slide14
DroughtWidespread persistent drought 1930s (Central and Northern Great Plains, Northwest, Great Lakes)1950s (Southern Plains, Southwest), 1980s (West, Southeast)First decade of the 21st century (West, Southeast)14
Trends (% per century)
1900 to 2011: -0.1%
1930 to 2011: -10.0%
1971 to 2011: +31.6%
Peterson, T. C. et al., 2012 (In Review). Ibid.Slide15
Projected Change (A2 Scenarios – “Higher Emissions”) in North American Precipitation (Late 21st Century)15
15 Climate Models
Global Climate Change Impacts in the United States, Thomas R. Karl, Jerry M. Melillo, and Thomas C. Peterson, (eds.). Cambridge University Press, 2009
.Slide16
Combined Drought Severity and Water Surplus16
NOAA U.S. Climate Extremes Index
http
://www.ncdc.noaa.gov/extremes/cei/Slide17
Extreme Snowstorms17Number of extreme snowstorms (upper 10 percentile) occurring each decade within the six U.S. climate regions in the eastern two-thirds of the contiguous U.S.
Most severe storms for each of the six climate regions from 1900 to 2010
Temperature Anomalies During Season of Extreme Events
Precipitation Anomalies During Season of Extreme Events
-1%
-9%
19%
5
%
-6%
8%
For the storms of record, the average temperature was below normal for each region
Every region had two of the five storms of record occurring during seasons with above average temperatures
Frequency
Precipitation
(Average Anomalies)
Kunkel, K.E
.,
et al
., 2012 (In Review).
BAMS
.Slide18
Tornadoes & Convective Storms18Although some ingredients that are favorable for severe thunderstorms have increased over the years, others have notOverall, changes in the frequency of environments favorable for severe convective storms have not been statistically significant
U.S. Annual Tornadoes
Kunkel, K.E
.,
et al
., 2012 (In Review).
BAMS
.Slide19
Tornadoes & Convective Storms19For continental U.S. severe tornadoes (L≥10 km), (top) total path length per year, and (bottom) the number per year
r² = 0.1269
r² = 0.27
Malamud, B. D.
and D. L.
Turcotte
,
2012
. Statistics of severe tornadoes and severe tornado
outbreaks.
Atmos
. Chem. Phys. Discuss
.
Length per year
(km/
yr
)
Number per year Slide20
Tornadoes & Convective Storms20Wind Shear vs. Vertical Velocity–6km proximity values
Each cell is best viewed as a conditional probabilityKunkel, K.E.,
et al., 2012 (In Review). BAMS.Slide21
SummaryWidely varying suitability of our data and physical understanding of various extreme events21Adapted from Lubchenco, J., and T. Karl, 2012. Predicting and managing extreme weather events.
Physics Today.Slide22
Questions?22