1. MONSOON EXPERIMENT IN SOUTH AMERICA (MESA) An internationally coordinated, joint CLIVAR – GEWEX program aimed at providing: 1.a better understanding of the South American monsoon system and its variability, 2.a better understanding of the role of that system in the global water cycle 3. improved observational data sets, and 4.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 ORGANIZATION MESA SWG VAMOS Project Office LPB

4. MESA Scientific Working Group Carolina Vera, Univ of Buenos Aires, Argentina (Chair) Tercio Ambrizzi, Univ. de São Paulo, Brazil E. Hugo Berbery, Univ of Maryland, USA Leila Vespoli de Carvalho, Univ. de São Paulo, Brazil Alice Grimm, Univ Federal de Paraná, Brazil Vern Kousky, NCEP/NOAA, USA Brant Liebmann, Climate Diagnostics Center, NOAA, USA Julia Nogues-Paegle, Univ of Utah, USA José Marengo, CPTEC, Brazil Ricardo Matano, Oregon State Univ. USA Carlos Nobre, CPTEC, Brazil Celeste Saulo, Univ of Buenos Aires, Argentina Anji Seth, IRI, USA Rafael Terra, Univ de la República, Uruguay Ed Zipser, Univ of Utah, USA

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. 19992000200120022003200420052006 CLAIRE DRY-TO-WET AMC CLAIRE 2001 SIVAM Planning, Data collection, Principal Research, Data development SALLJEX FLUX TOWERS Field experiment NDJF TRMM-WET AMC DJF MJJ Planning MJ SANTAREM-AMC J Model development (regional, global, coupled) simulations, sensitivity, validations and assessment of predictability SO Planning, Data collection, Research Activities, Data system development O Beginning of operat. SMOCC Development Synthesis Workshops 3* INPE-PCDs LBA-BARCA O Field Campaigns Monitoring Synthesis and Integration LBA Pase II LBA Time table

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. 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 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

10. Learning from SALLJEX: LLJs and MCS Observations and Modeling simulations confirm that LLJ actually feeds the moisture for the MCSs Large synergism between MCS and LLJs. MCS exert a large impact on low and upper circulation 66% of MCS occur during CJE and NCJE In 93% of CJE events convection occurs south of 20S 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 NCEP INITIAL DATA PSAS WITH SALLJEX 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