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VOCALS GOAL

VOCALS GOAL. Better understand, simulate, and predict the Southeast Pacific cool-ocean climate regime and its interactions with the larger-scale coupled ocean-atmosphere-land system on diurnal to interannual timescales. Central cool-ocean concerns. Regulation of SST

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VOCALS GOAL

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  1. VOCALS GOAL Better understand, simulate, and predict the Southeast Pacific cool-ocean climate regime and its interactions with the larger-scale coupled ocean-atmosphere-land system on diurnal to interannual timescales.

  2. Central cool-ocean concerns • Regulation of SST • Cloud-topped boundary layers

  3. The setting in the SEP • SEP cool region extends to equator, interacts with ENSO, has most persistent low clouds. • SEP has research-grade buoys and strategic islands. • Exploit SEP/NEP geographical/aerosol contrasts. • Strong international partners, particularly in Chile. • Productive upwelling, eddies, Peru and Chile basin

  4. VOCALS in CLIVAR • VOCALS is a process study developed within VAMOS. • VOCALS conceived in EPIC planning as follow-on to EPIC 2001 stratus pilot cruise, then refined in WG meetings at VPM3-7 (2000-2004) and Corvallis (2004). • Presented formally to U.S. CLIVAR in January, 2005 • VOCALS research elements informally began in 2003, to continue until 2010. • VOCALS has strong US and international participation: US (Albrecht, Bretherton, Cronin, Fairall, Huebert, Mechoso, McWilliams, Samelson, B. Stevens, S.-P. Xie, Weller, Wood) Chile (Garreaud, Ruttlant, Pizarro, Nunez) Uruguay (Terra) Ecuador (Cornejo) • SOLAS plans coordinated activities • Draft science and implementation plans: www.atmos.washington.edu/~breth UCAR/JOSS site: www.joss.ucar.edu/vocals/

  5. VOCALS Science Issues …based on what we have learned from EPIC, other SEP observations and modeling studies: • Atmospheric, oceanic, and coupled model biases and model improvement in the SEP and other subtropical cool-ocean regimes. • SEP aerosol-cloud interaction; implications for aerosol indirect effect and regional climate. • SST distribution and the ocean heat/tracer budgets in the SEP. • Role of South America and remote forcing from tropics and midlatitudes, on diurnal to interannual (ENSO) timescales.

  6. Cloud-aerosol feedbacks and indirect effect Manifest in POCs (pockets of open cells)? POCs Bretherton et al (2004)

  7. 00LT 06LT 12LT 18LT 06LT Garreaud and Munoz (2004) – 21 day regional MM5 simulation A daily gravity wave initiated by Andean slope heating enhances the diurnal cycle of cloud out to 1500 km offshore.

  8. Oceanic heat divergence (20S 85W) 2003 Weller 2002 2001 • Annual-mean heat flux into ocean ~ 30 W m-2 at 1500 km offshore under persistent low cloud! Why? …not Ekman fluxes. Upwelling also inadequate.

  9. VOCALSIMPLEMENTATION • Global and mesoscale model evaluation and improvement (e.g parameterization development) using multiscale data sets, sensitivity studies, and refined understanding of relevant physical processes. • Observational synthesis of existing data sets (e.g. buoy, satellite, reanalysis) and targeted measurement enhancements. • ‘Radiator Fin’ IOP in October 2007: detailed observations of SEP aerosol, clouds, ocean processes. • Co-ordination with oceanographic, aerosol, cloud process communities, including CLIVAR cloud CPT (NCAR/GFDL), IGBP/SOLAS, NOAA Climate Testbed (NCEP), ARM, Cloudsat, GCSS, etc.

  10. VOCALS Radiator Fin Experiment Goal: In-situ measurements of aerosols, cloud microphysics, and ocean mixing processes/heat fluxes 0-1200 km offshore. • October 2007 – month long field campaign • Aircraft: C-130 (endurance,payload) aerosonde (daily surveys, POC tracking) • Ship: Ronald H Brown (C-band radar, clouds) Wecoma (mesoscale SeaSoar survey) • San Felix Island: ARM Mobile Facility • Satellites: Coordinate with overpasses as feasible. • Chilean coast: surface measurements/soundings • S American-led coastal-zone IOP. • Near-real time atmospheric mesoscale modeling.

  11. VOCALS-RF motivating questions (distilled) 1. What factors influence drizzle formation and POCs? Is aerosol the critical factor? 2. What are the aerosol characteristics, sources and sinks in both the coastal and remote SEP? 3. What is the mesocale covariability of the atmosphere and the ocean? (SST, fluxes, aerosols, clouds) 4. What is the vertical structure of SEP mesoscale ocean eddies/waves. Do their lateral heat fluxes dominate ocean heat divergence in non-coastal SEP? Ditto for tracers. Can ROMs reproduce eddy/SST/tracer structure? 5. Do the phase speed and vertical structure of the Andean diurnal subsidence wave match model predictions? 6. Do satellite and ship-based retrievals of aerosol, cloud drop radius and drizzle agree with in-situ observations?

  12. VOCALS-RF Study Region

  13. West-East cross-section

  14. Flight pattern 1: Cross-section

  15. Flight pattern 2: POC drift

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