CPTEC’s Climate Simulations

over South America: A Preliminary Comparison A Preliminary Comparison

between the regional model between the regional model ETA and RegCMETA and RegCM

Julio Pablo Reyes Fernandez

Centro de Previsao do Tempo e Estudos Climaticos CPTEC

Divisao de Modelagem e Desenvolvimento DMD

Introduction:Introduction:

South America: tropical and South America: tropical and extratropical interaction, topographyextratropical interaction, topography

Last papers (Table 1)Last papers (Table 1)

PapersPapers

Objective:Objective:

Compare perfomance for January of Compare perfomance for January of 1998 for the regional climate models 1998 for the regional climate models in use at CPTECin use at CPTEC

ETA: operational and research, using ETA: operational and research, using GCM CPTEC/COLAGCM CPTEC/COLA

RegCM2.9: researchRegCM2.9: research

Main Differences: parameterizations, Main Differences: parameterizations, vertical coordinate, etcvertical coordinate, etc

Models

Design of ExperimentsDesign of Experiments

Austral summer (January), from 00Z16DEC of Austral summer (January), from 00Z16DEC of 1997 to 00Z1FEB of 1998 (spin-up)1997 to 00Z1FEB of 1998 (spin-up)

Area: Tropical South America (resolution 80km)Area: Tropical South America (resolution 80km)

Initial and boundary conditions: reanalysis Initial and boundary conditions: reanalysis NCEP/NCAR, every 6 hours and SST Reynolds et NCEP/NCAR, every 6 hours and SST Reynolds et al. 1995al. 1995

Model validation: for precipitation GPCP data, and Model validation: for precipitation GPCP data, and reanalysis for others fieldsreanalysis for others fields

ValidationValidation

Areas: Amazon, NE, SE, ANDES, Areas: Amazon, NE, SE, ANDES, South and allSouth and all

Precipitation: BIAS, THREAT SCOREPrecipitation: BIAS, THREAT SCORE

Wind of lower and upper levels (850 Wind of lower and upper levels (850 and 200hPa) and geopotentialand 200hPa) and geopotential

South AmericaSouth America

Analysis dataAnalysis dataGPCP

NCEP/NCAR

ETA BM

Preliminary resultsPreliminary results

ETA KF

Ctrl

Pbcmax

AS

FC

Impl

Preliminary resultsPreliminary results

The results showed a better The results showed a better perfomance of the RegCM vs ETAperfomance of the RegCM vs ETA

Tuning of the subgrid Tuning of the subgrid parameterizations are necessary in parameterizations are necessary in both modelsboth models

Change the radiation Change the radiation parameterization of the ETA modelparameterization of the ETA model

RegCM3RegCM3Simulations with new version and slightly modified parameters

El Niño Case

La Niña Case

Next FutureNext FuturePerform long integrations with both models Perform long integrations with both models

for validation with the present climate. for validation with the present climate.

1.- Use NCEP and ECMWF reanalysis1.- Use NCEP and ECMWF reanalysis

2.- Use GCM CPTEC/COLA2.- Use GCM CPTEC/COLA

The ultimate goal is their use in The ultimate goal is their use in experiments of paleoclimate and climate experiments of paleoclimate and climate changechange

Acknowledgements: Acknowledgements: PWCPWC’’s group at ICTPs group at ICTP

Thank you very muchThank you very much

Please, send questions, doubts and Please, send questions, doubts and comments to e-mail:comments to e-mail:

jpablo@cptec.inpe.brjpablo@cptec.inpe.br