“poc’s are the norm” hypothses - flow chart for sep

“ “ POC’s are the Norm” Hypothses - Flow Chart POC’s are the Norm” Hypothses - Flow Chart for SEP for SEP Clean marine aerosol advected into south of SEP that is in quasi equilibrium with low CO air and small 30 nm mode entrained from FT & grown via DMS Warmer surface waters heat and raise MR as air advects North under stronger subsidence inversion leads to clean turbulent St deck and increased entrainment “Clean layer” develops under strong inversion near cloud top via sedimentation of larger droplets leading to stabilization. Layer suppresses entrainment but may be eroded by more active night time convection. Meanwhile drizzle gradually reduces CCN throughout MBL Entrained CCN insufficient to compensate for drizzle, drizzle enhanced, Reff larger and transition to POC occurs. Clean layer no loonger eroded by clouds and entrainment suppressed. Clean FT aerosol above cloud CCN<15/cc @ %S-0.3 Polluted aerosol above cloud CCN>40/cc @ %s=0.3 Entrained CCN sufficient to partially or fully compensate for drizzle loss and transition to POC delayed or suppressed, Reff smaller - depending on pollution concentration Persistent above cloud flow probably coupled to upslope- downslope flow will spread out with easterly flow above clouds embeded in a southerly boundary layer flow at probably 200-500km/day. Clouds responding to entrinement from this upper layer will take on archlike shape anchored to the land sources. Long range FT transport can also add aerosol to the clouds elsewhere. WITHOUT THIS COMBUSTION SOURCE OF CCN – POCS WOULD BE THE NORMAL DEMISE OF THE St CLOUDS Nov 13, 2008 ~18:40 RF13 20S 30S Clean Polluted

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Nov 13, 2008 ~18:40. RF13. 20S. 30S. “POC’s are the Norm” Hypothses - Flow Chart for SEP. Clean marine aerosol advected into south of SEP that is in quasi equilibrium with low CO air and small 30 nm mode entrained from FT & grown via DMS. - PowerPoint PPT Presentation

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Page 1: “POC’s are the Norm” Hypothses - Flow Chart for SEP

““POC’s are the Norm” Hypothses - Flow Chart POC’s are the Norm” Hypothses - Flow Chart for SEPfor SEP

Clean marine aerosol advected into south of SEP that is in quasi equilibrium with low CO air and small 30 nm mode entrained from FT & grown via DMS

Warmer surface waters heat and raise MR as air advects North under stronger subsidence inversion leads to clean turbulent St deck and increased entrainment

“Clean layer” develops under strong inversion near cloud top via sedimentation of larger droplets leading to stabilization. Layer suppresses entrainment but may be eroded by more active night time convection. Meanwhile drizzle gradually reduces CCN throughout MBL

Entrained CCN insufficient to compensate for drizzle, drizzle enhanced, Reff larger and transition to POC occurs. Clean layer no loonger eroded by clouds and entrainment suppressed.

Clean FT aerosol above cloud CCN<15/cc @ %S-0.3 Polluted aerosol above cloud CCN>40/cc @ %s=0.3

Entrained CCN sufficient to partially or fully compensate for drizzle loss and transition to POC delayed or suppressed, Reff smaller - depending on pollution concentration

Persistent above cloud flow probably coupled to upslope-downslope flow will spread out with easterly flow above clouds embeded in a southerly boundary layer flow at probably 200-500km/day. Clouds responding to entrinement from this upper layer will take on archlike shape anchored to the land sources. Long range FT transport can also add aerosol to the clouds elsewhere.

WITHOUT THIS COMBUSTION SOURCE OF CCN – POCS WOULD BE THE NORMAL DEMISE OF THE St CLOUDS

Nov 13, 2008~18:40RF13RF13

20S

30S

CleanPolluted