Teleconnection Patterns and Seasonal Climate Prediction over South America The Final Chapter??? Tércio Ambrizzi and Rosmeri P. da Rocha University of São Paulo, São Paulo, Brazil EUROBRISA 2010 – Barcelona, Spain

OBJECTIVE To analyze in detail 21 years of ECWMF seasonal forecast simulations using basic statistical methods and particularly the linear wave theory, in order to evaluate the seasonal forecast skill and its useful value

(Dawson et al 2010 – CD) (1/3 º x 1/3 º and 0,83 º lat x 1,25 º lon) (1 º x 1 º and 1,25 º lat x 1,825 º lon)

DATA AND METHODOLOGY Climatological Data used : ECMWF/ERA40 – period 1982 – 2001 ECMWF Coupled GCM – Hindcast Period – 1982 – 2001 – 11 ensemble members – 6 months forecasting The seasons are: DJF (Summer), MAM (Fall), JJA (Winter), and SON (Spring) To create the seasonal datasets it was used the third month of each six months forecasting (PREV3) and three months seasonal forecasting (3MES) Pearson linear correlation was used in some of the analyzes The basic variables used in this presentation is Zonal (U) and Meridional Wind (V) Ray tracing analysis will be presented as well

PREV3 3MES Autum Winter Spring Summer

SimbolRegionsLatitudeLongitude RSSouth25º-35ºS60º-50ºW SDSoutheast15º-25ºS55º-65ºW COCentre West5º-15ºS60º-50ºW NDNortheast2.5º-12.5ºS45º-35ºW REGIONS WHERE THE MODEL WILL BE VALIDATED CONSIDERING THE 3MES AND PREV3

Zonal and Meridional Seasonal Wind at 200 hPa for ERA 40 and 3MES inside the previous four regions Model superstimate the zonal wind and understimate the meridional wind ND CO SD RS ND CO SD RS

U (850 hPa) V (850 hPa) U (200 hPa) V (200 hPa) TOTAL AMPLITUDE OF U AND V WIND FOR EACH ENSEMBLE MEMBER AND EACH FORECASTING MONTH (RS BOX)

ZONAL AND MERIDIONAL WIND ERRORS FOR THE SUMMER ZONAL WIND MERIDIONAL WIND ND CO SD RS ND CO SD RS

ZONAL AND MERIDIONAL WIND ERRORS FOR WINTER ZONAL WINDMERIDIONAL WIND ND CO SD RS CO SD RS

ZONAL WINDA COMPOSITES FOR DJF AND JJA (200 hPa – m/s) ERA40 PREV3 3MES DJF JJA

ZONAL WIND CROSS SECTION AT 30 o AND 50 o S FOR 3MES AND DJF - JJA (m/s) 30 o S DJFJJA 50 o S

LATITUDINAL MEAN SEASONAL ZONAL WIND at 200 hPa - (m/s) DJF JJA MAM SON

ZONAL WIND ERRORS PREV3/3MES – ERA40 DJF JJA PREV3 3MES

STATIONARY WAVENUMBER (K s ) - DJF ERA40 3MES K s Meridional cross section 120 o E 120 o W 65 o W

STATIONARY WAVENUMBER (K s ) - JJA ERA40 3MES K s Meridional cross section 120 o E 180 o 65 o W

SEASONAL RAY TRACING ANALYSIS FOR WAVE NUMBERS=2 and 3 (WN=2-3) (ERA40 AND ALL 11 MEMBERS) DJF MAM JJA SON WN2 WN3

PRECIPITATION MODEL’S BEHAVIOUR

SUMMER PRECIPITATION COMPARISON BETWEEN CMAP AND ERA40 ERA40 - CMAP ERA40 CMAP

WINTER PRECIPITATION COMPARISON BETWEEN CMAP AND ERA40 CMAP ERA40 ERA40 - CMAP

SEASONAL ZONAL MEAN PRECIPITATION (mm/day) DJF JJA MAM SON MODEL CMAP

SEASONAL PRECIPITATION COMPARISON BETWEEN CMAP AND MODEL FOR THE NORTHEAST BRAZIL“ND” DJF JJA MAM SON ModelCMAP El Niño years

SEASONAL PRECIPITATION ANOMALIES IN THE NORTHEAST BRAZIL BOX (ND) – ALL ENSEMBLE MEMBERS DJF JJA MAM SON

DJF JJA MAM SON SEASONAL PRECIPITATION COMPARISON BETWEEN CMAP AND MODEL AND SEASONAL PRECIPITATION ANOMALIES IN THE CENTER WEST BRAZILIAN BOX (CO) – ALL ENSEMBLE MEMBERS

SEASONAL PRECIPITATION COMPARISON BETWEEN CMAP AND MODEL AND SEASONAL PRECIPITATION ANOMALIES IN THE SOUTHEAST BOX (SD) – ALL ENSEMBLE MEMBERS DJF JJA MAM SON

SEASONAL PRECIPITATION COMPARISON BETWEEN CMAP AND MODEL AND SEASONAL PRECIPITATION ANOMALIES IN THE SOUTH BOX (RS) – ALL ENSEMBLE MEMBERS DJF JJA MAM SON El Niño

summary The GCM is not able to correctly represent the position of the maximum and minimum hemispheric zonal wind (large variability among the ensemble members) There are considerable errors in the amplitudes of the zonal and meridional wind over different regions of South America. The precipitation is overestimated in the hemispheric analysis but the model underestimate it in the different regions over South America. Ray tracing analyzes clearly suggest that the model is not able reproduce the expected wave trajectory because it does not represent the Southern Hemisphere zonal wind variability. Bigger wavenumber larger variability among the trajectories.

IS THIS THE END??

FUTURE WORK Repeat all previous analyzes for the Meteo Office and CPTEC hindcast data. Select some specific years to analyze the atmospheric circulation over South America in order to determine some dynamical aspects of the model ensemble members and their deviation. We have to look more careful at ENSO years A Scientific paper is underway containing the main results of the first part of this work One M.Sc. Dissertation was concluded and the work was presented in some international conferences.

GRUPO DE ESTUDOS CLIMÁTICOS THANK YOU FOR YOUR ATTENTION AND TO EUROBRISA FOR THE OPPORTUNITY TO WORK IN THIS PROJECT CLIMATE STUDIES GROUP