The VAMOS Ocean-Cloud-Atmosphere-
Land Study
Robert Wood, University of Washington

Mesoscale ocean eddies
Improving understanding, model simulations, and prediction of the
Southeast Pacific Climate
System
Field Program and Modeling
Regional pollution
Stratocumulus clouds

• Cold SSTs, coastal upwelling, subsidence
• Cloud-topped MBLs
• Influenced by and influential on remote climates (ENSO)
• Unresolved issues in heat and nutrient budgets
• Important links between clouds and aerosol
• Poorly simulated by atmosphere-ocean GCMs

GFDL
change in low cloud amount for
2

CO
2 model number from Stephens (2005)
CCM

source: IPCC 2007

Surface mooring with 1-year turn-around starting October 2000
SW and LW, precipitation. Two systems. Sampling: 1 minute and PACS cruise explorations of SEP stratus above 250 m. Sampling: 7.5 to 60 minutes
Telemetry: Hourly surface met, not on GTS.
POCs
WHOI stratus buoy

Mesoscale variability in stratocumulus

VOLCANOES
• Locations and strengths of sources of natural and anthropogenic aerosols and precursors
• Regional distribution of aerosol. Relative contribution of anthropogenic and natural sources
• Effects of aerosol on micro and macrophysical cloud properties
DUST
SMELTERS
DMS

Global cloud droplet concentration
(MODIS, annual mean 2001-2004)

MODIS
Cloud Droplet
Concentration
(SON 2001-2004)
Smelter locations

Comparison of in-situ and satellite microphysical properties

D=0.05 m m
Tomlinson et al. (2007)
Sulfuric Acid
D=0.2 m m
Ammonium
Bisulfate
50 100 150 200 250
Temperature [C]
Results indicate that submicron aerosol is predominantly composed of a mixture of sulfuric acid and ammonium bisulfate

200 km

• Open cell coverage can be significant
• Strong synoptic and intraseasonal variability
• Association with drizzle

• Strong reductions in accumulation mode aerosol concentration
• New nucleation
• Links between aerosol microphysics and cloud macrophysics?

Field Program to address VOCALS science questions
Chiefly sponsored by NSF and NOAA, with contributions from ONR, DoE, and international agencies
When: Oct-Nov 2008
Scientific Program Overview NSF Proposal
Robert Wood , VOCALS-REx PI, University of Washington
Christopher Bretherton , GEWEX/GCSS Representative, University of Washington
Barry Huebert , SOLAS Representative, University of Hawaii
C. Roberto Mechoso , VOCALS Science Working Group Chair, UCLA
Robert Weller , Woods Hole Oceanographic Institution

VOCALS-Rex will collect datasets required to address a set of issues that are organized into two broad themes:
• Aerosol-cloud-drizzle interactions in the marine boundary layer (MBL) and the physicochemical and spatiotemporal properties of aerosols
• Chemical and physical couplings between the upper ocean, the land, and the atmosphere.

AEROSOL-CLOUD-DRIZZLE HYPOTHESES
•
Variability in the physicochemical properties of aerosols has a measurable impact upon the formation of drizzle in stratocumulus clouds over the SEP
• Precipitation is a necessary condition for the formation and maintenance of pockets of open cells (POCs) within stratocumulus clouds
• The small effective radii measured from space over the SEP are primarily controlled by anthropogenic, rather than natural, aerosol production, and entrainment of polluted air from the lower free-troposphere is an important source of cloud condensation nuclei (CCN)
• Depletion of aerosols by coalescence scavenging is necessary for the maintenance of POCs.

COUPLED-OCEAN-ATMOSPHERE-LAND
HYPOTHESES
•
Oceanic mesoscale eddies play a major role in the transport of heat and fresh water from coastally upwelled water to regions further offshore
• By changing the physical and chemical properties of the upper ocean, upwelling has a systematic and noticeable effect on aerosol precursor gases and the aerosol size distribution over the SEP
• The diurnal subsidence wave (“upsidence wave”) originating in northern Chile/southern Peru has an impact upon the diurnal cycle of clouds that is well-represented in numerical models
• The entrainment of cool fresh intermediate water from below the surface layer during mixing associated with energetic nearinertial oscillations generated by transients in the magnitude of the trade winds is an important process to maintain heat and salt balance of the surface layer of the ocean in the SEP.

NSF C-130 NOAA Ronald H Brown
DoE ASP G-1 CIRPAS Twin Otter

• Standard instruments : Microphysics, Turbulence,
Thermodynamics suite
• Remote sensing : Wyoming Cloud Radar
(zenith+nadir+slant), Cloud Lidar (zenith), Microwave radiometer (183 GHz, zenith), AIMR (nadir), MODIS
Airborne Simulator (MASTER, nadir), BBRs
• Chemistry/aerosols/clouds : LDMA, RDMA, ToF
Mass Spec, nephelometer, PSAP, CN counters
(+ultrafine), CCN, CVI, Cloud water collector,
Impactors
• Dropsondes

• Remote sensing : Cloud profiling radar (94 GHz, motion stabilized), C-band scanning radar, Microwave radiometer (21/32/90 GHz), Laser ceilometer, Wind profiler, BBRs
• Meteorology : Flux tower, Turbulence, Meteorology suite
• Oceanography : XBTs, ADCP, SeaSoar, Ocean microstructure profiles, SST sensors, thermistor chains
• Chemistry/Aerosols : DMS + fluxes, Aerosol composition (impactors, PILS), Ozone, Radon,
Nephelometers, PSAP, DMA/APS, CCN (5 channels)

• Standard instruments : Microphysics (PDPA,
FSSP, CIP), Turbulence, Thermodynamics suite
• Remote sensing : 94 GHz FMCW radar, chaff dispenser
• Chemistry/aerosols/clouds : PCASP, 2 CPCs,
DMA/TDMA, CCN, SP2 (black carbon)
• Towed platform (optional)

• Standard instruments : Microphysics,
Turbulence, Thermodynamics suite
• Chemistry/aerosols/clouds : Aerosol size distribution/conc (PCASP, FIMS, CPC), composition (PILS, ToF aerosol mass spectrometer), CCN, nephelometer, aethelometer, O
3
, CO, SO
2
, DMS/organics

• Standard instruments : Microphysics, Turbulence,
Thermodynamics suite
• Remote sensing : Microwave Radiometer
(MARSS), Shortwave Spectrometer (SWS), Spectral
Hemispheric Irradiance Measurement (SHIM), BBRs,
Heiman, Airborne Research Interferometer Evaluation
System (ARIES)
• Chemistry/aerosols/clouds : CCN, CPC, Aerosol mass spectrometer, SP2 (black carbon), filters, CVI, nephelometer (dry/wet), PSAP

• Improved simulation of the large-scale circulation in the atmosphere and mesoscale ocean eddy transports of heat and biogenic species offshore over the SEP
• Detailed process modeling (LES, chemistry, eddy resolving ocean models…)
• Multiscale simulation and prediction system
• Improved representation of the aerosol indirect effects over the SEP by regional and/or global models

GOAL: To critically assess the ability of the models (atmospheric, chemical transport….) to simulate the salient characteristics of the
VOCALS region
WHY?: Learn more about model biases, current ability of CTMs to forecast for REx etc.
A means for leveraging REx data
- successful endeavor during previous VAMOS projects (e.g. NAME)

• 3-hourly data for October 2006 gridded to 1x1 o resolution over the VOCALS Region (0-40 o S, 60-
110 o W)
• Fields:
– meteorology
– clouds (LWC, fractional coverage, microphysics)
– major aerosol and precursor species
• Not all fields can be grounded with observations, but many can:
– GOES (diurnal clouds)
– MODIS (clouds, microphysics)
– Quikscat (surface winds)
– AMSR (WVP, cloud LWC)
– CloudSat/CALIPSO (drizzle, MBL depth,…)

• NCAR CAM (Rasch/Breth)
• WRF-Chem (Fast)
• NASA GMAO (Bacmeister)
• GFDL (Ramaswamy)
• ECMWF (Koehler)
• NCEP GFS (Pan)
• iROAM (Y. Wang)
• U. Chile WRF (Garreaud)
• COAMPS (S. Wang)
• MMF (Khairoutdinov)
• Other modeling groups are welcome.

• Improved large scale coupled ocean-atmosphere model simulations and predictions of the SEP climate system through a coordinated modeling and observational program
• Integrated datasets (IDs) , and complete data archive
• Development of a multi-scale simulation and prediction system
• Education and training for both US and regional climate scientists.

0 50 100 150 200 250 300
0 g m 5 10 15 20 25 30 m m
1000 cm -3
Liquid water path Effective radius Cloud drop conc.
open cells closed cells
250 km
MODIS 10/19/2001; 10:00 Local (16:00 UTC)

Planning
Phase
REx and
Modeling
Workshops
IUGG Perugia
Field site surveys
VOCALS
REx
VOCALS
Conference
2003
- 2006
2007
PI
Proposal submission
2008 2009 2010
Field and modeling synthesis/analysis

IGBP’s Surface Ocean Lower
Atmosphere Study (SOLAS) has formally agreed to collaborate with
CLIVAR on VOCALS. http://www.uea.ac.uk/env/solas/
In the remote marine atmosphere the supply of DMS and its oxidation mechanisms limit the rates of new particle nucleation and growth.
These processes probably control the re-filling of POCs with clouds. Iodine, ammonia, and organics may also play a role.
SOLAS proposes to study this chemistry from both ships and aircraft.

CFS
Errors
• The CFS model has significant errors in the SEP
Pre c
• There is a meridional shift in ITCZ (top), a warm SST bias (middle) and insufficient stratocumulus cloud cover,
(bottom)
• These errors adversely affect the skill of CFS climate forecasts (ENSO).
SS
T
What model developments are required to alleviate these errors?
CLD

Roberto Mechoso , UCLA, USA (chair)
Chris Bretherton , Univ of Washington, Seattle,
USA
Chris Fairall , NOAA/ESRL, Boulder, USA
Barry Huebert , Univ of Hawai`i at Manoa, USA
Jim McWilliams , UCLA, USA
Oscar Pizarro , U Concepción, Chile
José Rutllant , U Chile, Santiago, Chile
Bob Weller , WHOI. Woods Hole USA
Hemantha Wijesekera , Oregon State Univ., USA
Robert Wood , Univ of Washington, Seattle, USA
Shang-Ping Xie , IPRC, Univ of Hawai`i, USA
Carlos Ereño , Int'l CLIVAR
José Meitín (ex officio), NCAR EOL/VAMOS
Office

• SST Biases in NCAR CCSM (Collins et al. 2006)

SST Stratus Cloud Amount (Warren)
Net CRF