VOCALS

VOCALS THEME To better understand and simulate how marine boundary layer cloud systems surrounding the Americas interact with the coupled ocean-atmosphere-land system on diurnal to interannual timescales.

VOCALS in CLIVAR VOCALS is a developing process study within VAMOS, informally led by C. Bretherton. WG meetings at VPM3-6. Active participants: US (Albrecht, Bretherton, Fairall, Mechoso, Miller, Stevens, Weller) Chile (Garreaud, Ruttland) Uruguay (Terra) Peru (Lagos) Ecuador (Cornejo) Science Plan on my web page.

VOCALS Scientific Issues Time and space scales of CTBL-continent interaction. Regional S/I feedbacks between Sc clouds, surface winds, upwelling, coastal currents and SST in E Pacific. Feedbacks of Eastern Pacific cloud topped boundary layer properties on overall tropical circulation and ENSO. Climatic importance of aerosol-cloud interactions.

VOCALS STRATEGIES Global and mesoscale model evaluation and improvement (e.g parameterization development) using multiscale data sets. Model sensitivity studies to refine hypotheses and target observations. Science by synthesis/use of existing data sets, enhancement through targeted instrument procurement, algorithm evaluation and development, and enhanced observation periods. Co-ordination with oceanographic, aerosol, cloud process communities, including CLIVAR CPTs, CLOUDSAT, etc.

Arica Lima San Felix I. WHOI buoy Galapagos I. Scientific Highlights from EPIC & DYCOMS DYCOMS-II TAO-EPIC EPIC2001-Sc RICO

TAO-EPIC has gathered a nice multiyear dataset Yearly Feb-Apr precip in SE Pacific ‘ITCZ’ …and freshening Cronin

2.5 years of data from the WHOI stratus buoy (20S 85W) Weller

Buoy shows large net heat flux into ocean balancing eddy cooling Weller

Ocean altimetry shows energetic eddy field Weller

EPIC 2001 Sc cruise x GOES-10 Visible Image October UTC 10 ° S 20 ° S 90 ° W80 ° W70 ° W Peru x

Inhomogeneous clouds 60 km Latitude (ºS) GOES VIS 0545 LT C-band 0200 LT km Longitude (ºW) Height (km) October 19 (Local Time) MMCR 00 06

[cm s -1 ] ECMWF VERTICAL VELOCITY [dBZ] EPIC2001-Sc Diurnal Cycle (20S, 85 W) Bretherton et al. (2004) Daytime subsidence max

AM subsidence max PM subsidence max Diurnal variation of horizontal surface wind divergence (Quikscat) Hypothesis: Subsidence wave driven by diurnal heating cycle over Andes reaches buoy at noon. seabreeze ? Wood

18LT 06LT MM5 simulation also shows late afternoon convergence at coast, midnight ascent at buoy! Garreaud et al. (2004)

Remotely-sensed cloud microphysics from EPIC2001-Sc Bretherton et al. (2004) Significant drizzle in clean periods, but mainly evaporates

MODIS visible reflectance, 15Z 20 Oct POC (patch of cells)

MODIS effective cloud droplet radius – large (clean) in POC small in coastal pollution

DYCOMS-II RF02 POC – drizzle feedback? Stevens

DYCOMS-II Sc entrainment estimates from RF01 Stevens

Comparison of 6-day mean 20S 85W profiles with models All models have adequate Sc, but too shallow a PBL. CAM2 LWC all in lowest 3 levels ( m). Observed LWC mainly at m. (Peter Caldwell, UW)

U. Chile has installed ceilometer and surface met at San Felix Is. LCL (surface met) Cloud base (ceilometer) Shows daytime rise of LCL, cld. base, with synoptic variations Well-mixed Decoupled Mostly clear Garreaud

Other active issues Role of Andes and Amazonia (flow blocking, deep convection) in influencing Sc. Comparison of WHOI buoy and TAO-EPIC ocean energy budgets with GCMs. Interest in coastal oceanography of region, including O-A interactions thru trapped coastal (e.g. Kelvin) waves. ENSO feedbacks with SE and NE Pacific clouds Shallow cumulus dynamics/microphysics – Sc to Cu transition (McCaa and Bretherton 2004; Wang et al. 2004)

VOCALS Thrusts Continuing diagnostic, model sensitivity, parameterization studies of SE/NE Pac stratocumulus and variability based on past field studies, satellite/model products, and in-situ observational enhancements. Contribution to RICO (Jan 2005, shallow Cu) Add ocean diagnostic study component based on ARGO/ODA, cruises, WHOI buoy aimed at better understanding of ocean upwelling/lateral heat transport processes and their reln. to atmospheric variability. Global atm./coupled, mesoscale atm., and regional ocean modeling. ‘Radiator fin’ coupled O-A-L expt. (Oct 2006)

Augment San Felix Island instrumentation with wind profiler, radiation, microwave LWP, and aerosol sampler. NOAA/ETL sfc/remote sensing instrumentation on Pacific and Atlantic buoy maintenance cruises, and at RICO (funded). Develop VOCALS data set through distributed satellite/model/in situ data archive at JOSS. Archive ECMWF and NCEP hi-res column data at WHOI buoy, SFI in co-ordination with CEOP (some funding). Work with cloud-climate sensitivity CPT to feed into coupled model development. VOCALS short-term implementation

VEPIC Timeline Modeling, empirical, and satellite studies diagnostic/modeling work 2003 ETL-enhanced cruises SFI profiler VEPIC data archive 2004/11 Cloudsat 2005/01 RICO 2006/10 Radiator expt.

RICO (Rain In Cumulus over the Oceans)

Requested (Fairall) Pan Am Panel Endorsement?

Diurnal subsidence wave Cld microphys. gradient Ocn heat transport Coastal jet

What VOCALS would like from you A letter from the panel to Mike Patterson endorsing the use of the Ron Brown in RICO to provide critical time-continuous open-ocean radar, radiometric, turbulence, and other in-situ measurements that will greatly enhance RICO’s potential to contribute to shallow cumulus and cloud microphysical parameterizations in climate models. Panel approval of VOCALS as a US CLIVAR sanctioned activity as part of PACS funding AOs. Also, panel must consider equatorial EPIC’s heritage.