MONSOON EXPERIMENT IN SOUTH AMERICA (MESA)

1. MONSOON EXPERIMENT IN SOUTH AMERICA (MESA) An internationally coordinated, joint CLIVAR – GEWEX program aimed at providing: a better understanding of the South American monsoon system and its variability, a better understanding of the role of that system in the global water cycle improved observational data sets, and improved simulation and prediction of the monsoon and regional water resources. Carolina Vera Univ. of Buenos Aires MESA SWG Chair Presented by Jose Marengo Member MESA SSC

2. MESA IMPLEMENTATION HYPOTHESIS: The SAMS provides a physical basis for determining the degree of predictability on short- and long timescales over the region. • MESA PRIORITY RESEARCH • AREAS (PRA): • Better understanding and • simulation of: • diurnal and mesoscale processes • (PRA-I); • intraseasonal variability • (PRA-II) • interannual and longer time • variability (including ACC issues) • (PRA-III); • monsoon evolution and • variability (PRAs-I, II, III).

3. MESA SWG VAMOS Project Office MESA ORGANIZATION LPB

4. MESA Scientific Working Group

5. MESA scientific issues discussed in VPM7, 8 & CLIVAR Baltimore meeting A better undestanding and improved simulation is expected on: • Diurnal cycle and seasonal evolution of the SAMS • 3-dimensional description of the low-circulation east of the Andes. • Mesoscale convective processes • Role of aerosols from biomass burning in SAMS • Dynamics of the SA see-saw pattern • ITCZ-SACZ interaction • Influence of MJO on SAMS • Relative roles of internal vs forced low-frequency variability • Land surface forcing – Impacts of land use change • Role of remote and local SST – South Atlantic • Global response to SAMS forcing • Sources and limits of predictability on SAMS region Model simulation improvements are needed in reproducing: • the seasonal cycle of SAMS • Diurnal Cycle of circulation and precipitation • Monsoon onset • Mean and variability of the SACZ

6. Additional MESA modeling issues • To what extent do model systematic errors affect seasonal predictability in the region? • Why do models have deficiencies in reproducing the SACZ? Missing coupled A-O mechanisms in the AGCMs? • Will seasonal predictability change as a function of land cover changes? • Can soil moisture memory help for seasonal predictions for South America? Need to improve soil moisture obs. • Dealing with the complexities of orography. Higher resolution models and/or dowscaling with regional models? • Atlantic SST forcing: (i) understanding tropical versus extratropical contributions. • How can intraseasonal variability in the SAMS can be improved in the models?Can instraseasonal oscillations be a source of short term climatic predictability? • At the end, can we expect that model improvements and observational techniques will improve predictability in regions such the highly populated and economically important one in SE South America? • - Better seasonal climate predictions, more accurate projections of climate change scenarios for the future?

7. LBA Time table 1999 2000 2001 2002 2003 2004 2005 2006 Planning Planning, Data collection, Principal Research, Data development Planning, Data collection, Research Activities, Data system development Development Model development (regional, global, coupled) simulations, sensitivity, validations and assessment of predictability Synthesis Workshops 3* Field Campaigns Beginning of operat. CLAIRE MJJ Field experiment TRMM-WET AMC LBA Pase II DJF DRY-TO-WET AMC SO SALLJEX ND JF Synthesis and Integration CLAIRE 2001 MJ SANTAREM-AMC J SMOCC LBA-BARCA O Monitoring INPE-PCDs SIVAM O FLUX TOWERS

8. MESA Time table • Meeting outcomes: • MESA implementation Plan • MESA milestones • MESA Timeline • MESA SWG TORS YEAR (2001+) 01 02 03 04 05 06 07 08 … SALLJEX Planning …-------| SALLJEX Preparations -----------| SALLJEX Data Collection -----------| SALLJEX Post-field activities -------------| PLATEX Planning --------------| PLATEX Preparation ---------| PLATEX Data Collection ------------… MESA Principal Research … ---------------------------------------------… MESA Data Management --------------------------------------…

9. SALLJ Science goal To understand the role of the South American low-level jet in moisture and energy exchange between the tropics and extratropics and related aspects of regional hydrology, climate and climate variability • SALLJEX Objectives • Diurnal variations of the SALLJ • Detailed description of the 3-dimensional structure of the SALLJ • The relationship between MCCs and the SALLJ • Description of the heat low over the Chaco and NW Argentina

10. Learning from SALLJEX: LLJs and MCS Observations and Modeling simulations confirm that LLJ actually feeds the moisture for the MCSs 66% of MCS occur during CJE and NCJE In 93% of CJE events convection occurs south of 20S Large synergism between MCS and LLJs. MCS exert a large impact on low and upper circulation Ageostrophic wind (left) and geostropic wind (right) at 850 hPa on 06Z19DEC2002 (Difference between control and NLH runs)

11. PRECIPITATION FORECAST WITH THE REGIONAL ETA MODEL WITH SALLJEX DATA -CPTEC (24h) OBSERVED PSAS WITH SALLJEX NCEP INITIAL DATA 2 centers 2 centers Rozante and Cavalcanti, 2004

12. MESA IMPLEMENTATION PLAN-OUTLINE (DRAFT) Part 1: MESA Scientific Objectives Part 2: Scientific Rationale Part 3: The MESA Program 3.1 PRAs Framework 3.1.1 SAMS Life cycle 3.1.2 Diurnal and mesoscale variability 3.1.3 Intraseasonal variability 3.1.4 Interannual and interdecadal variability 3.1.5 Climate Change 3.1.6 Paleoclimate 3.2 MESA Modeling and Data Assimilation 3.3 MESA and the South Atlantic 3.4 The MESA hydroclimatic component over La Plata Basin 3.5 Project structure and Timeline Part 3: MESA Field Component Part 4: Dataset development and Data management Part 5: Programmatic Context 5.1 Project infrastructure 5.2 Education and Training 5.3 Link with other programs

13. MESA MILESTONES • FY04: • Quantitative information of the model errors in SALLJEX • Evaluation of impact of SALLJEX data on analysis and forecasts • Confirmation about the ability of the models to reproduce some of the elements of the low-level circulation of the SAMS • Preparation of GEF-PLATIN survey reports • FY05: • SALLJEX Data Assimilation. • Planning of LPB CSE monitoring activities. • Assessment of the IPCC-AR4 simulations in the SAM region. • FY06: • Assessment of Seasonal prediction simulations in the SAMS region. • Development of MESA climate indexes • Seasonal simulation of SALLJEX season. • LPB CSE monitoring implementation. • Predictability of the SAM associated with Atlantic SST simulations. • Regional downscaling of IPCC-AR4 simulations. • FY07: • LPB CSE experiment implementation, data collection, and integration. • Assessment of extreme event frequency changes in the regional climate change scenarios for South America and their impact on agricultural activities. • FY08: • Evaluate the impact of soil moisture in simulations and predictions. • Hydrological studies of PLATEX data • …Ultimate goal: Integrated view of the American Monsoon Systems, related interhemispheric connection, monsoon predictability and prediction