Recent climatic trends over the Mediterranean and future ... weizman_31May05_al… · Recent climatic trends over the Mediterranean and future projections Pinhas Alpert Dept. Geophysics

GLOWA GLOWA –– Jordan RiverJordan River

Recent climatic trends over the Mediterranean and future projections

Pinhas AlpertDept. Geophysics and Planetary Sciences,Tel-Aviv University, Israel

With: S.O. Krichak, I. Osetinsky, M. Dayan, L. Sever,H. Saaroni, B. Ziv, H. Shafir. K. Bassat,

P. Kishcha, T. Ben-Gai

In cooperation with: Israeli Ministryof Science and Technology

Financed by: German Federal Ministry of Education and Research

Principal Objectives for GLOWA JR I Principal Objectives for GLOWA JR I

• To determine the vulnerability of water resources in Israel in response to climate change

• To develop sustainable management practices in the watershed of the Jordan River

See Poster by J. Daniels next to Registration

Climatic TrendsClimatic Trends

Outline(Observations vs. Projections)

1. Temperatures 2. Rainfall3. Extreme Temperature4. Extreme Rainfall5. Synoptic systems6. Open questions


1. Temperatures

a. Observed trendsb. Predicted trends

Trend summer (JJA) temperature (°C/100y)- NNRP reanalysis

Warming trend of 1.5 – 4°C/100y,mostly over W- Med & Egypt, ~3-4 times that of the global trend

See Poster: Saaroni et al.H. Saaroni, B. Ziv, J. Edelson, and P. Alpert, 2003, Long-term variations in summer temperatures over the Eastern Mediterranean, Geophysical ResearchLetters, 30, 18, 1946, 2003 (DOI:10.1029/2003GLO17742)

Summer (JJA) MaximumTemperatures

2071-2100 compared to 1961-1990Regional Climate Modelling (ICTP & TAU)

IS92 a

IS92 a

IS92 a

IS92 a

The SRES marker emission scenarios and theresulting change in concentration

concentrationsemissions

Summer (JJA) MaximumDifferences-Temperatures

Raisinen (Personal Communication)

Some Paradoxes in Israel Climatic TrendsSome Paradoxes in Israel Climatic Trends

The Temperature Paradox in Israel

Summer Temperatures IncreaseWinter Temperatures Decrease

Total trend: None

Surface Temp. Trends in Israel (1965 Surface Temp. Trends in Israel (1965 –– 95) 95)

Summer

Winter

Ben-Gai, Bitan,Manes, Alpert, 1998: TAC

Winter Temperatures in Israel & NAO Winter Temperatures in Israel & NAO

a. Winter Tmax & NAO

b. Winter Tmin & NAO

Ben-Gai, Bitan, Manes, Alpert,Kushnir, BLM,2001

NAO 1950-1994

Winter NAO 1950 - 1994

Distribution of the shape of the1948-2000 curve trendsof the 850 hPa temperatures

(See Poster)

Like GlobalTrend

Ziv, H. Saaroni, A. Baharad, D. Yekutieli and P. Alpert, The indications for aggravationin summer heat conditions over the Mediterranean Basin. Geophysical Research Letters (in press)


2. Rainfall


Rainfall Trends (1958Rainfall Trends (1958--1998)1998)

Alpert, P., 2004: “The water crisis in the E. Med and relation to GlobalWarming?”, in Water in the Mid-east and N. Africa (Ed. Zereini & Jaeschke),Springer, p. 55-61.


Italy Rain1951-1995

N. Italy

Central Italy

S. Italy20% reduction

Sharp gradient in Trends over Israel

Steinberger & Gazit – Yaari, J. Climate, 1996

Precipitation

0

100

200

300

400

500

600

40s 50s 60s 70s 80s

mm

/ a Um Qeis

IrbidRamtha

Salameh

GCM prediction: further aridification and increasing variability

Winter (DJF) Rainfall DifferencesWinter (DJF) Rainfall Differences


The Rainfall Paradox in IsraelNorth Israel- Decreasing trendsSouth Israel- Increasing trends

Why increase in the south?(In 2003/4 – just the opposite; change of trends since 90s?)

Possible answers:•Land-use change•Tele-connections,•Synoptic changes•All the above; factor separation?

Red-Sea Trough

Alpert, P. et al, 2004: Semi-objective classification for daily synoptic systems,Application to the E. Mediterranean climate change, Intern. J. of Climato. Vol 24 (in press)

Droughtperiod

RedRed--Sea Trough Days per YearSea Trough Days per Year(1948(1948--2000)2000)

Cyprus Low days per year Cyprus Low days per year (1948(1948--2000) 2000)

Alpert, P. et al, 2004: Semi-objective classification for daily synoptic systems,Application to the E. Mediterranean climate change, Intern. J. of Climato. Vol 24 (in press)

Reconstructed Albedo

Ben-Gai et al (1998)

Ben-Gai et al (1993)


3. Extreme Temperatures


Distribution of 850 mb daily summer temperatures

•Shift in the mode •Increase in extreme events

Saaroni, Ziv, Alpert, 2003: Long-term Variations in Summer Temperatures, over the Eastern Mediterranean (GRL, Vol 30, p. 1946)

850 hPa(32.5ºN, 35ºE)

Histogram forDuration (d) of hot/cool spells(850 mb NNRP reanalysis)

0

5

10

15

20

25

30

35

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Length (No. of days)

No.

of s

pells

Cold Hot

1975-1948

0

5

10

15

20

25

30

35

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Length (No. of days)

No

Cold Hot

2002-1976Ziv, H. Saaroni, A. Baharad,D. Yekutieli and P. Alpert,2005,The indications for aggravationin summer heat conditions overthe Mediterranean Basin. GRL (in press)

Effects of extreme temperatures

• Fruit loss (fall-out) particularly in Citrus

• Longer periods of hot spells cause1. increase in water consumption 2. damage to young fruit

Thanks to Jiftah Ben-Asher

Tmax, summer, Har-Knaan

15

20

25

30

35

40

45

50

0 10 20 30 40 50 60 70 80 90 100

percent (%)

Tmax

(C)

observed control B2 A2Following Deque

Downscaling Daily Temperatures (1961-1990)

Tmax, Har-Knaan, corrected

15

20

25

30

35

40

45

50

0 10 20 30 40 50 60 70 80 90 100

percent (%)

Tmax

(C)

observed control B2 A2

Har-Knaan, TMAX, distribution

0123456789

10

15 20 25 30 35 40 45 50

TMAX (C)

Perc

ent (

%)

observed control control correctedB2 B2 corrected A2A2 corrected

Har-Knaan, TMAX, distribution

0

1

2

3

4

5

6

7

8

9

10

15 20 25 30 35 40 45 50

TMAX (C)

Perc

ent (

%)

observed control corrected B2 corrected A2 corrected


4. Extreme Rainfall


SpainSpain-- Trend in daily Rainfall CategoriesTrend in daily Rainfall Categories(~400 (~400 raingaugesraingauges))

Natural separation of categories

Alpert et al, GRL,2002

Trend

IsraelIsrael-- Trend in Rainfall CategoriesTrend in Rainfall Categories(~ 40 (~ 40 raingaugesraingauges))

Heavy categories (C1,C2) UPLight categories (A,B) DOWN

Alpert et al, GRL,2002

precipitation, Har-Knaan, log

0.1

1

10

100

1000

0 10 20 30 40 50 60 70 80 90 100

percent (%)

prec

ipita

tion

(mm

/d)


Downscaling Daily Rainfall (1961-1990)

precipitation, Har-Knaan, corrected, log, centiles

0.1

1

10

100

1000

0 10 20 30 40 50 60 70 80 90 100

percent (%)

prec

ipita

tion

(mm

/d)


precipitation, Har-Knaan, corrected, zoom, centiles

2030405060708090

100110120130140

95 95.5 96 96.5 97 97.5 98 98.5 99 99.5 100

percent (%)

prec

ipita

tion

(mm

/d)


precipitation, Har-Knaan, corrected, zoom2, centiles

50

60

70

80

90

100

110

120

130

140

99.5 99.6 99.7 99.8 99.9 100

percent (%)

prec

ipita

tion

(mm

/d)



The Extreme Rainfall Paradox in the Mediterranean

Total Rain decreasesExtreme rainfall increases

Answer:

Change of rainfall distribution

Change in Temp. Distributions under Change in Temp. Distributions under Global Warming (3 Options)Global Warming (3 Options)

IPCC, 2001

The 4th optionThe 4th option

Decrease in mean & increase in variance

Is this paradoxical behavior really occurring in the Mediterranean?

Yes, P. Alpert, T. Ben-Gai, A. Baharad, Y. Benjamini, D. Yekutieli, M. Colacino,

L. Diodato, C. Ramis, V. Homar, R. Romero, S. Michaelides and A. Manes,The paradoxical increase of Mediterranean extreme daily rainfall in spite ofof decrease in total values” Geophys. Res. Lett., 29, 11, 31-1 – 31-4, (June issue),2002.

Trends (%) in total versus Heavy Precipitation

Ben-Gai et al,TAC, 1999


5. Synoptic systems


B2 – dynamics of technological change continue along the historical trends Observed CO2 and other GHG

ECHAM- Winter lows

ECHAM-Persian Trough

1950-2099

ECHAM-Black & RedHadCM3- Green & Blue

B2 – dynamics of technological change continue along the historical trends Observed CO2 and other GHG

ECHAM4

HadCM3-


Do global models “see” the recent synoptic

trends?

ECHAM vs. NCEP reanalysis (1950ECHAM vs. NCEP reanalysis (1950--2000)2000)Annual frequencies of Synoptic SystemsAnnual frequencies of Synoptic Systems

The good news

RedRed--Sea Trough days per year Sea Trough days per year (1948(1948--2000)2000)

The Bad news

ECHAM

NCEP reanalysis

Cyprus Low days per year Cyprus Low days per year (1948(1948--2000)2000)

The Bad news

NCEP reanalysis

ECHAM


Some unanswered questions?


Question No. 1:

Are seasons changingIn the E. Mediterranean?

Alpert,P., Osetinsky, I.,Ziv, B. and Shafir, H., 2004:"A New Definition to the Seasons Based on Synoptic Systems and Example for Israel", Intern. J. Climatology,(in press)

Months

Synoptic systems’ frequencies averaged over 1948Synoptic systems’ frequencies averaged over 1948--20002000

Definitions of the SeasonsDefinitions of the Seasons

synoptic

31 1 13 22 25 1 1 1 7 12 22 23

--|----JUNE --|- -JULY- -|-AUGUST-|--SEPTEMBER

high season

temperature

meteorological

astronomical

summersummer

Definitions of the SeasonsDefinitions of the Seasons

synoptic

1 7 12 22 1 17 1 1 2 14 21 30

|--DECEMBER--|-JANUARY--|FEBRUARY-|---MARCH-----

high season

temperature

meteorological

astronomical

winterwinter


Question No. 2:How large are the errors in

the global climate models caused by‘ignoring’ land-

use changes?

Regions of major LUCLUC over 40 years (1950 – 1990), HYDE database

desertificationdesertification deforestationdeforestationcultivationcultivation

CultivationCultivation-- N. AustraliaN. Australia

1. agriculture

2. pasture

5 18

Natural vegetation classificationnorthnorth southsouth

CultivationCultivation-- Saudi ArabiaSaudi Arabia


Question No. 3:Do we really know the rainfall distribution over the E. Mediterranean?

For instance, where is the maximum?

NNRP

1998/9

1999/00

2000/01

E. Mediterranean RainfallE. Mediterranean Rainfall-- 5 winters5 wintersTRMM satellite vs. NNRP15 reanalysisTRMM satellite vs. NNRP15 reanalysis

TRMM

Total-5 winters

2002/3

2001/2

E. Mediterranean Rainfall E. Mediterranean Rainfall TRMM satellite vs. NNRP15 reanalysisTRMM satellite vs. NNRP15 reanalysis

NNRPTRMM

E. Mediterranean Rainfall 2003/4(DecE. Mediterranean Rainfall 2003/4(Dec--Feb)Feb)TRMM VS. TRMM VS. MesoscaleMesoscale modelmodel

TRMM MM5- fine20 km

MM5-coarse60 km

SUMMARY• Large-scale IPCC predictions over the Mediterranean

suggest: 3-35% rainfall reductions; 3-5 Deg warming by 2071-2100.

• Nearly all the Mediterranean shows significant rainfall decreasing trends.

• In Israel, there are mixed rainfall trends with increases over the south.

• Rainfall increases over the south are partly due to land-use changes and partly due to synoptic increase of Red-Sea Trough frequency.

• Winter temperatures in Israel are dropping due to NAO increase and hence due to global warming!

Past 420,000 y

CO 2concentration

Temperature-anomalies

Tropical effects on Mediterranean Weather & Climate

HurricaneOlga

IndiannMonsoonAfrican

Monsoon

DUST

El-Nino


Thank you!



Question No. 3:

Why increase in the south?

This year 2003/4 – just the opposite; change of trends since 90s?

850 hPa absolute maximum & minimum temperatures for July/August at (32.5ºN, 35ºE)

Min. Temp. Trend = +0.06 K/10y

14

17

20

23

26

29

32

1948 1958 1968 1978 1988 1998

Years

Max

/Min

Tem

pera

ture

s (K

)

Max. Temp. Trend = +0.195 K/10y

H. Saaroni, B. Ziv, J. Edelson, and P. Alpert, 2003, Long-term variations in summer temperatures over the Eastern Mediterranean, Geophysical ResearchLetters, 30, 18, 1946, 2003 (DOI:10.1029/2003GLO17742)

Past 420,000 y

CO 2concentration

Temperature-anomalies

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Recent climatic trends over the Mediterranean and future ... weizman_31May05_al… · Recent climatic trends over the Mediterranean and future projections Pinhas Alpert Dept. Geophysics