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

2. MESA ORGANIZATION BY 2004 VAMOS Project Office

3. 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

4. PLATIN 2004 Activities The CLIVAR-GEWEX PLATIN SSG: La Plata Basin is a climate-hydrology system with components that are potentially predictable with useful skill from seasons in advance, and whose variability has important impacts on human activities. PLATIN is intended to advance in the understanding of those components. *GEF PROJECT *LPB CSE

5. MESA NEW ORGANIZATION MESA Scientific Working Group VAMOS Project Office … LPB Implementation Steering Group

6. 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

7. 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).

8. MESA scientific issues discussed in VPM7 & 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

9. Additional MESA modeling issues discussed in VPM7 & Baltimore meeting 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.

10. 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?

11. MESA modeling activities defined in VPM7 2004: –Impact of improved soil moisture initializations on precipitation simulation –Impact of improved initial conditions enhanced by SALLJEX data –Data Assimilation including SALLJEX data 2005: –Intraseasonal variability during SALLJEX period. –Seasonal mean representation of the SALLJEX period. –SALLJEX data assimilation in the CDAS analysis (and GDAS?) –…–… 2006: –…–…

12. 1 st MESA SWG Meeting Wednesday 9 th afternoon: Session 1: Review of the scientific basis for MESA Session 1a:PRA-1: Diurnal and Mesoscale Variability in the SAMS region Thursday 10 th, morning: Session 1b:PRA-2: Intraseasonal variability in the SAMS region Thursday 10th, afternoon: Session 1c:PRA-3: Interannual and longer-time variability in the SAMS region. Friday 11 th, morning: Session 2:Additional MESA Modeling Session 3:MESA Applications. PLATIN Friday 11th, afternoon: Session 4:Enhanced observation activities & Field campaigns in MESA MESA SWG Executive Session

13. 1 st MESA SWG Meeting Moderators and rapporteurs of the plenary sessions: Session 1a: PRA-1: Diurnal and Mesoscale Variability in the SAMS region Moderator: Ed Zipser, Rapporteur: Rafael Terra Session 1b: PRA-2: Intraseasonal variability in the SAMS region Moderator: Julia Nogues-Paegle, rapporteur: Leila Carvalho Session 1c: PRA-3: Interannual and longer-time variability (including ACC) in the SAMS region. Moderator: P. Silva Dias, Rapporteur: A. Grimm Session 2: Additional MESA modeling issues Moderator: I. Cavalcanti, Rapporteur: Anji Seth Session 4: Enhanced observation activities & Field campaigns in MESA Moderator: H. Berbery, Rapporteur: C. Vera

14. 1 st MESA SWG Meeting Plenary sessions: Brief summary of the session by the moderator Discussion of the main scientific questions to be addressed in each of the PRAs Discussion of the diagnostic, modeling, and field campaign activities needed to address them

15. VAMOS A TRABAJAR! LET’S START TO WORK!