“Extremes constitute the major stress factor on a number of environmental and socio-economic systems.” (Heino et al., 1999)

WORLDWIDE INTEGRATED STUDY OF EXTREMES (WISE)

Objective: To better understand the occurrence, evolution and role of extremes within the climate system (and to contribute to their better prediction)

• It is expected that the exact nature of the objective will evolve somewhat as the effort proceeds.

• The effort is initially focusing on droughts and extended

wet periods

• Extremes are an important aspect of GEWEX Phase II Roadmap

A FOCUS ON EXTREMES …

1995 First considered

2003 Ad hoc group to consider a working group

2004 Go-ahead for working group

2005 (July) I agreed to initially lead working group

2005 (now) Developing pragmatic plan

Outline of Presentation

• Objectives and Background• Initial Focal Points• Specific Examples of Extremes

CEOP period Canadian Drought Initiative

• Trends• Data Base for Extremes• Summary and Next Steps

AN OVERALL PERSPECTIVE

• What extremes have occurred?• How do extremes develop, evolve and end within the

climate system?• Have extremes changed in occurrence and

character?• Why did (or did not) the occurrence and

characteristics of extremes change?• Given our progress, how can we contribute to

assessing whether extremes may change in the future?

Issue: How wide should our scope be?

FOCAL POINTS

It is critical to develop a small number of specific, unique and do-able actions

Although complementary, two initial ones:

• GHP builds on WEBS ‘products’ and other activities

• CEOP one scientific component of a larger effort

1. WISE and WEBS …

Extremes have always been a critical part of the GHP strategy

Since:• WEBS has focused on longer-term averages• Numerous CSE-related studies have included extremes

Then capitalize on these experiences:• Synthesis effort to collectively address water and energy

budgets, flows and feedbacks during extremeslonger period than CEOP (say 1995-2004)many relevant studies completed

SPECIFIC ISSUES

• What are the ‘water and energy cycling’ characteristics of extremes?

• What processes and feedbacks were responsible for these evolving features in different regions?

Summary of MRB Annual Water and Energy Budgets

ARTICLE OUTLINE

Objective of Article: Synthesize our understanding of how droughts/extended wet periods develop, evolve, and end with emphasis on factors over land areas

Contents: Current information as a basis additional analyses to be determined

Authorship: Multi-authors

Mode of operation: Iterate …

2. WISE and CEOPObjective• Advance our understanding of extremes including their occurrence,

characteristics and inter-connections.

Approach:• Examine extremes individually over the CEOP period• Relate these individual events to each other as well as to the overall climate

system

Questions specifically associated with this approach include: • What extremes occurred during CEOP over the world? • What are the characteristics of these extremes? • How did the cycling of water and energy occur within these extremes? • To what degree were the extremes inter-connected?

Outcome:• “Synthesis’ article on addressing such issues

CONTRIBUTORS OF EXTREMES INFORMATION DURING CEOP

and counting … Drought over Australia Alan Seed and …Heat wave over Europe Christoph Schaer plus …Flooding in NZ Warren Gray/David WrattExtremes- South America Hugo Berbery Drought over Canada Ron Stewart and …

Drought over US Rick Lawford and …Drought/floods in Asia Bill Lau/Ben BurfordBrazil extremes Jose MarengoGPCC/GPCP Bruno Rudolf

…

2001 2002

2003 2004Nov/03 – Nov/04

Impact of the summer 2003 in Europe

Agricultural losses:12.3 Billion US$ (SwissRe estimate)

Serious problems with- freshwater resources (Italy)- forest fires (Portugal)- freshwater fish (Switzerland)

Shortage of electricity, peak prices on spot market (EEX, Leipzig)

Estimated 22,000 to 35,000 heat deaths (excess mortality)

August 2003 temperatures relative to 2000-2002, 2004(Reto Stöckli, ETH/NASA, MODIS)

Estimation of Return Periods

10 y10 y

1000 y1000 y

100 y100 y

mean

Average of 4 Stations: Zürich, Basel, Berne, Geneva

1864-2003

(Gra

zzin

i et

al.

200

4)

Anomaly 500 hPa Circulation(August 2003)

L H LH

L

Atmospheric Circulation

Sequence of blocking high-pressure systems• Summer Northern Hemisphere Annular Mode, wave-number 3 (Ogi et al. 2005)• Rossby wave train (Grazzini et al. 2004, Black et al. 2005, Orsolini and Nikulin 2005)

Anomaly 500 hPa Circulation(17. Juli – 6. August 2003)

(Og

i et

al.

200

5)

’=40m

H

H

H

L

L

LL

NEW ZEALAND FLOODS

Manawatu: 21 Feb Manawatu: 21 Feb

Masterton: 17 Feb Masterton: 17 Feb

February 2004

NEW ZEALAND FLOODING

• Damage estimated at $300M …probably worst flood damage on record (inflation adjusted)

• Rainfall analysis suggests an over 1:150 year event on time scales up to 72 h

Intense precipitation events

The role of the Low-level jet east of the

Andes

South American Extremes

A CANADIAN NATURAL DISASTER

The The 1999-2004 drought1999-2004 drought

was one of the worst was one of the worst natural disasters that natural disasters that Canada has ever suffered!Canada has ever suffered!

Huge impacts on:societyeconomyecosystems

Southern Saskatchewan, April 2002

IMPACTS OF THE 1999-2004 DROUGHT

• GDP (01/02) - $5.8B• Employment (01/02) - 41,000• Natural pond depth lowest on record• Largest die-back of aspen in recorded history• Negative net farm income in some provinces (1st

time in 25 years)• Huge increase in forest fires• Curtailed hydroelectric power – increase in electric

rates• 32 massive Saskatchewan dust storms• Thriving grasshopper populations• Farm and business bankruptcies• Failed water wells due to reduced groundwater• Surface water supplies depleted

OBJECTIVE OF THE STUDY

To better understand the physical characteristics of and processes influencing Canadian Prairie droughts, and to contribute to their better prediction, through a focus on the recent severe drought that began in 1999

The Team: John Pomeroy and I (co-leads) plus ~ 25 investigators

OUR STRATEGYPhysical-Dynamic Approach

• Improve understanding and model representation of processes

• Improve understanding and simulation of the whole system

• Contribute to better prediction

Focus

• Given limited resources, important to focus on a particular period to reach ‘critical mass’

• Natural focal point is the recent catastrophic drought that can be examined with unparalleled information

• Given our detailed understanding of this event, can compare it against others over the region and elsewhere at different times

QUANTIFY THE DROUGHT

Saskatoon

Swift Current

Calgary

Red Deer

Lethbridge

Drumheller

Medicine Hat

Gem

Olds

Verlo

Tyner

Orton

Hague

Cluny

Bruno

Warner

Warman

Ponoka

Instow

Elnora

Barons

Vanscoy

Swanson

Sibbald

Pakowki

Okotoks

Enchant

Duchess

Cypress

Blucher

Stettler

Mud Lake

Irricana

Elkwater

Conquest

Cessford

Shaunavon

Saskatoon

Pine LakeInnisfail

Gull LakeDuck Lake

Cavendish

Carseland

Big Stone

Oldman Dam

High River

Hand Hills

Del Bonita

Sylvan Lake

Dickson Dam

Smith Coulee

Many Springs

Buffalo LakeBuffalo Lake

Buffalo North

Sounding Creek

Crestomere Lake

Kirkpatrick Lake

Forty Mile Coulee

Legend

Observation Well Locations

0 30 60 90 12015Kilometers

Observational Networks

GRACEsatellite

MODIS and aerosols

Wells in SouthSaskatchewan

CRITICAL FACTORS

Individual storm events

“Hot spots”(Koster et al.2004)

Varying vegetation between droughtand non-drought

Snow WaterEquivalentAnomaly (mm)

PRAIRIE HYDROLOGY DROUGHT FACTORS

Non-contributing areas

Localized hydrology affected by poor drainage,storage in small depressions

UNDERSTAND THE DROUGHTV

ertic

al S

cale

S to ra ge o f W a te r

D r o u g h t

N o n - d r o u g h t

H o rizo nta l F lu x o f W a te r

N o n - d r o u g h t

D r o u g h t

3. TRENDS AND EXTREMESIt is not clear whether there needs to be a separate initiative on trends in

extremes

• Has the frequency and/or character of extremes changed over the last few decades? Why or why not?

And possibly …

• Will the frequency and/or character of extremes change over the next few decades? Why or why not?

Considerations:

pro: critical issue in many regions strong existing GHP community activities already underway (several examples here)con: being covered elsewhere?

within the scope of GEWEX?

Hans-Jörg Isemer, IBS, isemer@gkss.de GHP#11, September 2005, Melbourne, Australia

BACC (7): Selected example material from chapter 2

www.gkss.de/BACC

Variation of annual precipitation amount over Denmark, 1874-2004 (Cappelen and Christensen 2005).

4. DATA BASE FOR EXTREMES

How can we document the occurrence of extremes of interest to GHP?

• many web sites now on hazards (check our web site!)• individual inputs from CSEs and others

Suggestion:• Data base for extremes of interest to GHP

One possible step:• Using the CEOP period as a initial focus

Note: This is linked with the establishment of development of robust definition(s) of extremes

WISE “Guys”

• BK Basu• Hugo Berbery• Ben Burford• Ole Chrstensen• Hans-Joerg Isemer• John Roads• Alan Seed• Ron Stewart• Kiyatishu Takahashi• Steve Williams• Eric Wood• and others to be added

SUMMARYWe are just starting our focused activity on extremes

Natural initial focal point are:• building on WEBS and other studies (article ~ 3 y)• in combination with CEOP (article ~ 3-4 y)• trends

A challenging issue• data base for extremes

BREAK OUT• Is our present objective still appropriate?

• Are our initial issues and components OK?

• Should we include trends?

• How do we best address ‘defining’ extremes?

• To what extent should we produce an extremes data base?

• What specific actions do we have (with what outcomes)?

• Who leads these?

• What are our timelines

MEETING PLANS

Potential special sessions at international conferences

• Extremes session at 2006 CEOP workshop• Proposed WISE session at 2006 autumn AGU • Hydrological Cycle Symposium at IUGG 2007

(Italy)• …