GMI Stratospheric Hindcasts

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GMI Stratospheric Hindcasts

• Use FVGCM winds
• Include chlorine/bromine, solar cycle UV,
  volcanic aerosols
• Two runs
• One with "cold" NH winter
• One with "warm" NH winter

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Some Results from GSFC 50-Year Simulation

• Used 50-year FVGCM simulation with variable SST
  (1949-1999)
• Included chlorine/bromine, solar cycle UV,
  volcanic aerosols
• Simulation begun in 1973 now in early 1995
• Second simulation with no volcanic aerosols begun
  in 1979 now in 1983

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Total Ozone zonal means from model simulation
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RedFVDAS BlueFVGCM
HCl columns over NDSC stations for GMI runs
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RedFVDAS BlueFVGCM
Nitric acid columns over NDSC stations for GMI
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Stratospheric vs Tropospheric Ozone

• Parameterized tropospheric ozone calculated from
  GEOS-CHEM production and loss
• Stratospheric ozone transported into troposphere
  with just losss from GEOS-CHEM
• Ratio gives estimate of stratospheric
  contribution to tropospheric ozone

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Fraction of ozone that is "stratospheric" upper
trop
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Fraction of ozone that is "stratospheric" near
surface
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Control Run with No Volcanic Aerosol

• 50-year run includes volcanic aerosol variation
  taken from SAGE-based climatology
• We started a rerun from 1979 in which we repeat
  the 1979 seasonal cycle of aerosol surface areas

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FVGCM Experiments

• We have completed a second 50-year FVGCM run with
  repeating mean SST
• We are about to begin a delta ozone
  experiment-changing ozone in the radiation code
  of the GCM
• We are running a set of on-line radon tracers
  from different regions