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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

extreme extremes 2012 climate extremes extreme climate 2012 waves temperature precipitation noaa review bams storms cold knowledge understanding severe

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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