On the simulation of regional climate in South America

with emphasis on extremes and surface processes

Claudio Menéndez, Andrea Carril, Anna Sörensson,

Romina Ruscica, Pablo Zaninelli

CIMA

25 April 2011, 2nd UMI-IFAECI Meeting

Recent and ongoing activities

1. Analysis of large scale variability influencing the regional climate

2. Evaluation and intercomparison of climate simulations at the regional scale

3. Study of land surface–atmosphere interactions

25 April 2011, 2nd UMI-IFAECI Meeting

1. Analysis of large scale variability influencing the regional climate

To what degree can we relate the regional changes in variability/extremes to changes in the large scale atmospheric circulation?

How does anthropogenic climate change influence the likelihood of occurrence of extreme weather/climate phenomena?

Recent and ongoing work:

• IPCC AR4/CMIP3 models Influence of the SAM on extreme indices (Menéndez & Carril, 2010, Climatic Change)

• Data sets from different reanalyzes (e.g. 20CR, ERA40) + AGCM experiments + other available “long” simulations (e.g.) Influence of tropical SST anomalies on the regional variability (including extremes)

25 April 2011, 2nd UMI-IFAECI Meeting

“ENSO flavor” experiment

• 7 x 30 yr simulations with ECHAM4 (carried out by A. Cherchi at CMCC, Italy)

• Control: climatological SST

• 3 El Niño-like runs: climatological SST +idealized positive anomalies over the tropical Pacific

• 3 La Niña-like runs: climatological SST +idealized negative anomalies over the tropical Pacific

Ongoing collaboration with Italy (CLARIS LPB)25 April 2011, 2nd UMI-IFAECI Meeting

Exploring temperature extremes in different data sets

Cold nights (25th perc Tmin) Warm days (75th perc Tmax)

e.g. 20CR reanalysis

Dec

emb

er

Dec

emb

er

Mar

ch

Mar

ch

(P. Zaninelli)

Fraction of days in

1980-2000 exceeding the

75th percentile of Tmax in 1960-1980

Fraction of days in 1980-2000 not exceeding the 25th percentile of Tmin in 1960-1980

25 April 2011, 2nd UMI-IFAECI Meeting

25 April 2011, 2nd UMI-IFAECI Meeting

2. Evaluation and intercomparison of climate simulations at the regional scale

How do we assess models performance in a region with (high) uncertainty in the observations?

How the models reproduce the climate of the region and its variability in a climate change context?

What skills do models need to be considered useful for different applications?

Recent and ongoing work:

• Assessment of 6 RCMs for simulating different month-long “extreme” periods (Menéndez et al., 2010, Climatic Change)

• Assessment of regional climate change simulations (RCA3 driven by ECHAM5-OM, Sörensson et al., 2010, Meteorol. Z.)

• CLARIS-1 multi-model ensemble 1991-2000 (Carril et al., submitted)

• Participation in CLARIS LPB

CLARIS-1 multi-model ensemble 1991-2000

maximum temperature DJF

75th PERCENTILE

Region: SESA

(Carril et al., submitted)25 April 2011, 2nd UMI-IFAECI Meeting

CLARIS-1 multi-model ensemble 1991-2000

maximum temperature DJF

75th PERCENTILE

LMDZ

OBS

ENS

Region: SESA

(Carril et al., submitted)25 April 2011, 2nd UMI-IFAECI Meeting

CLARIS-1 multi-model ensemble 1991-2000

precipitation DJF

DJF MEAN, all South America

(Carril et al., submitted)

CRU

CMAP

“OBSERVATION UNCERTAINTY”

ENSEMBLE BIAS

ENS - CRU

But verification with different datasets leads

to different results…

25 April 2011, 2nd UMI-IFAECI Meeting

17 April 2011, 2nd UMI-IFAECI Meeting

3. Study of land surface–atmosphere interactions

Are there particular regions of strong interaction soil moisture-atmosphere in southern South America?

Recent and ongoing work:

• We identified parts of LPB as a region of potentially strong coupling between soil moisture, evapotranspiration and precipitation through experiments with RCA (e.g. Sörensson & Menéndez, 2011, Tellus A).

• To explore the influence of these interactions on the variability of precipitation (including occurrence of heavy precipitation)

• Incorporation of dynamic vegetation into RCA for South America is planned

25 April 2011, 2nd UMI-IFAECI Meeting

Summer soil–evapotranspiration-precipitation coupling in South America

Evaluating the degree of soil moisture - atmosphere interaction, using ensembles of simulations performed with a regional climate model (RCA3)

Sörensson & Menéndez, 2011, Tellus A

Koster et al., 2003, Exchanges:

25 April 2011, 2nd UMI-IFAECI Meeting

Exploring soil moisture-precipitation coupling

R. Ruscica

CS pp * std pp

65 W 60

W 55

W 50

W 45

W

40 S

35 S

30 S

25 S

20 S

-0.05

0

0.05

0.1

0.15

0.2

25 April 2011, 2nd UMI-IFAECI Meeting

Anomalies of top soil moisture

horizontal gradient, “day -2”

std pp S - std pp W

65 W 60

W 55

W 50

W 45

W

40 S

35 S

30 S

25 S

20 S

-0.1

-0.05

0

0.05

0.1

0.15

std pp S - std pp W

65 W 60

W 55

W 50

W 45

W

40 S

35 S

30 S

25 S

20 S

-0.1

-0.05

0

0.05

0.1

0.15

Standard Deviation of precipitation (ensemble S – ensemble W)

in two different time-scales: daily and 6-day mean precipitation

Rainfall variance forced by soil moisture

R. Ruscica25 April 2011, 2nd UMI-IFAECI Meeting

RCA3 coupled to the dynamic vegetation model LPJ-GUESS RCA-GUESS

A. Sörensson & P. Samuelsson25 April 2011, 2nd UMI-IFAECI Meeting

17 April 2011, 2nd UMI-IFAECI Meeting

Exploring synergies with scientists from other disciplines…

Sörensson & Menéndez, 2011, Tellus A

Examples during the last year:

Exchange of ideas and information of common interest with colleagues from Biological Sciences and Ecology (Pedro Flombaum)

Sea temperature affects fishing Cold conditions negatively affect the fishing industry in Argentine waters. Is there any relation with the dominant modes of variability in the climate system (ENSO, SAM) ? (collaboration with INIDEP, CONICET)

Project on adaptation to climate change with social scientists and different partners (including Red Cross and government entities) (International Research Initiative on Adaptation to Climate Change, Canada)

17 April 2011, 2nd UMI-IFAECI Meeting

“ENSO flavor” experiment

Ongoing collaboration with Italy (CLARIS LPB)