Air-Sea Interactions in the SAMS Region

Paulo NobreCPTEC/INPE

III Reunião de Análise e Previsão Climática do PMTCRH para o Nordeste do Brasil em 2005.

Recife, 17 de março de 2005.

SAMS CLIMATE VARIABILITY & CONVERGENCE ZONES

From: Grodsky and Carton (2002)

ITCZITCZ

SACZSACZ

SITCZSITCZ

Seasonal Precipitation Anomaly CorrelationCPTEC AGCM simulation and CAMS precip.

DJF MAM

From: Marengo et al. (2002)

Nordeste’s Rainfall PredictabilityNordeste’s Rainfall Predictability

personal com.L. MarxCOLA

800W 600W 400W 200W 00 200E

200N

00

200S

200N

00

200S

(B)

(A)

WET

ACOOLER SST

WARMER SST

ITCZ

A

The Atlantic ITCZThe Atlantic ITCZThe Atlantic ITCZThe Atlantic ITCZ

ITCZ

A

A

COOLER SST

WARMER SST

DRY

Adapted from: C. A. Nobre and L. C. B. Molion (1988)

MeridionalGradientSSTA

ATLANTIC ITCZ POSITION AND OLRANOMALY CORRELATION

MAM CPTEC AGCM T062L28ANOMALY CORRELATION

TAUY

RAINFALL

South Atlantic Convergence Zone & SSTA

Prescribed SST anomaly fields

COLD WARM

Nobre et al. (2002)

Nobre et al. (2002)

Nobre et al. (2002)

Chaves and Nobre (2004)

SST DIFFERENCES: OGCM EXPERIMENTS

Warm-Ctrl: Wind + SW

Cold-Ctrl: Wind + SW

CPTEC CGCM SISTEMATIC ERRORS

DFJ Precip Anomaly Correlation

AGCM SIMULATIONS

CGCM PREDICTIONS (October IC)

CPTEC CGCM – AGCM DFJ PRECIP ACOR

Observations: The PIRATA Array

R/V ANTARES

The PIRATA BACKBONE The PIRATA BACKBONE and the SW EXTENSIONand the SW EXTENSION

Background map: Mean No. of SST observations/month COADS 1961-90

(LAMEPE-2002)

(INMET-2004)

To be moored by July 2005.

PIRATA SWE & JASON/T-P ground tracks

ITCZ Sounding Experiment-2006

CTD Stations

SPSP

F. NoronhaFortaleza

Natal

Final Remarks

• Convergence zones represent important mechanisms modulating precipitation variability over South America.

• ITCZ: planetary scale, strongly modulated by SST: – Prediction of SSTA over the tropical (South) Atlantic.

• SACZ: Regional scale, coupled phenomena: – 1-Tear approach is a need.

• Needs: – Coupled model development (eastern basin St. deck),– Coupled data assimilation,– Ensemble prediction techniques, – Sustained ocean observation strategies (e.g. PIRATA)…