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)
(1/3º x 1/3º and 0,83º lat x 1,25º lon)
(1º x 1º and 1,25º lat x 1,825º 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
3MESAutum
Winter
Spring
Summer
Simbol Regions Latitude Longitude
RS South 25º-35ºS 60º-50ºW
SD Southeast 15º-25ºS 55º-65ºW
CO Centre West 5º-15ºS 60º-50ºW
ND Northeast 2.5º-12.5ºS 45º-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 superstimatethe 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 WINTERZONAL WIND MERIDIONAL WIND
ND 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 30o AND 50oS FOR 3MES AND DJF - JJA (m/s)
30oS
DJF JJA
50oS
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 (Ks) - DJF ERA40
3MES
Ks Meridional cross section
120oE
120oW
65oW
STATIONARY WAVENUMBER (Ks) - JJA ERA40
3MES
Ks Meridional cross section
120oE
180o
65oW
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
MODELCMAP
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 THANK YOU FOR YOUR ATTENTION AND TO EUROBRISA FOR THE OPPORTUNITYAND TO EUROBRISA FOR THE OPPORTUNITY
TO WORK IN THIS PROJECTTO WORK IN THIS PROJECT
CLIMATE STUDIES GROUP
