Global sea surface temperature October 25 th 2007

Transcription

1 The VOCALS Regional Experiment Aerosols, clouds, and precipitation in southeast Pacific stratocumulus Robert Wood Atmospheric Sciences University of Washington

2 Global sea surface temperature October 25 th

3 ISCCP inferred St/Sc amount

4 Twomey Albrecht

5 Rich marine habitats, few continental ones SeaWIFS Ocean Color Tarapacá, Atacama Desert Net primary productivity of Humboldt current 3 tc ha 1 yr 1 Net primary productivity of boreal forests 2 8 tc ha 1 yr 1 Iquique annual precipitation nfall [mm] rain

6 20 o S

7 Longitudinal cross section at 20 o S 85 o W 65 o W

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9 SST anomaly from zonal mean ERBE net cloud ERBE net cloud forcing

10 A coupled problem Correct prediction of stratus properties is important for the correct prediction of the climate over the tropical warm pool connections with ITCZ through both ocean and atmosphere Yu and Mechoso 2001 Precip [mm day 1 ]

11 SST Biases in Coupled Models SST Biases in NCAR CCSM (Collins et al. 2006)

12 Ocean surface heat budget Net heat input into ocean at center of stratus sheet > 50 W m 2 2 Must be corresponding cold water transport from somewhere Annual Heat Fluxes 20 o S, 85 o W 250 Net SW W W/m Net LW Latent Sensible Net Heat Bob Weller, WHOI

13 Mesoscale ocean eddies Mesoscale ocean eddies form in coastal upwelling regions and propagate westward Their impact on the heat, nutrient, and freshwater budgets is poorly known They are not resolved in coupled GCMS Simulation from Penven et al. (2005)

14 Mesoscale ocean eddies Height SST Eddies impact SST and can be observed using altimetry courtesy Shang Ping Xie, University of Hawaii

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16 14 year animation of eddies identified using satellite altimetry (courtesy Dudley Chelton, OSU)

17 Clouds and cloud processes

18 ERBE SWCF (W m 2 ) NCAR GFDL Clouds in Global l Models GMAO Annual mean Control run Atmospheric models

19 Why this Uncertainty? resolution of ~5m required to resolve inversion! ~12K! Free tropospheric T set by ITCZ θ e 2,000km ~1km BL T set by local SST

20 Drizzle is important over the SEP

21 Mesoscale variability in stratocumulus

22 200 km Pockets of Open Cells (POCs)

23 Mesoscale stratocumulus structure Cloud albedo strongly gy dependent upon open/closed cells Open Cells Low albedo Satellite Closed Cells 100 km Strong precipitation associated with open cell structure High albedo Open cells form in clear marine environment potential anthropogenic impacts Strong drizzle Ship Radar Weak drizzle

24 Drizzle and cloud droplet concentration EPIC data, Bretherton et al. (2004)

25 POCs and Aerosols Strong reductions in accumulation mode aerosol concentration New nucleation Links between aerosol microphysics i and cloud macrophysics?

26 Global cloud droplet concentration (MODIS, annual mean ) 2004)

27 Cloud Microphysical i Variability Smelter locations MODIS Cloud Droplet Concentration (SON ) Cloud droplet concentration [cm 3 ]

28 The VAMOS Ocean-Cloud-Atmosphere- Land Study Ai t t ti iti l di t i d d t di d d l Aim: to promote activities leading to improved understanding and model predictions of the SEP coupled system on diurnal to interannual timescales

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30 THE VOCALS STRATEGY

31 VOCALS Regional Experiment (REx) 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.

32 VOCALS REx Platforms NSF C 130 NOAA Ronald ldh Brown DoE ASP G 1 CIRPAS Twin Otter

33 The aircraft DoEASP G 1 CIRPAS Twin Otter Chemistry and aerosols, cloud microphysics, turbulence Remote sensing and cloud imaging NERC Dornier 228 NSF C 130 Chemistry and aerosols, cloud microphysics, turbulence, radar/lidar remote sensing Radar remote sensing, microphysics, turbulence Aerosols, cloud microphysics, i radiative measurements UK FAAM BAe 146

34 The Ships IMARPE José Olaya NOAA Ronald H Brown

35 VOCALS REx Platforms and Sampling Aircraft: NSF C 130 CIRPAS Twin Otter DoE G 1 UK BAe 146 NERC Do 228 Ships: NOAA Ronald H Brown José Olaya Land sites: Iquique Paposo

36 VOCALS-REx Cross-Section Sampling Combined NOAA Ronald H Brown and NSF C 130 Missionsi direct evaluation of GCM lower direct evaluation of GCM lower tropospheric structure

37 Flight plan for C 130 POC Drift missions

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39 Operations Bases Arica (Operations Center) C 130, G 1, UK 146, Do228 Iquique CIRPAS Twin Otter, Sounding station Paposo Ground station for aerosol characterization

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