Solar Forcing on Climate Through Stratospheric Ozone Change

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Solar Forcing on ClimateThrough Stratospheric
Ozone Change

• Le Kuai

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Objectives

• Quantify the solar influence on the climate
  change.
• - UV radiation changes 3.4
• - through ozone in stratosphere
• Explore the effect of the solar variability
• -on ozone, radiative heating rates
• -influences on climate dynamics and
• stratosphere-troposphere coupling

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The Statement of Problem
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Stratosphere

• Dynamical interannual variability
• 1) the annular modes (NAM, SAM)
• 2) QBO in the tropics
• 3) Solar cycle

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Solar Cycle vs Annular Modes

• Solar UV variations
• temperature and ozone changes in stratosphere
• Propagate downwards to troposphere

• NAM tends to its negative phase at solar min
• SAM
• - extend to upper stratosphere at solar max
• - confined in tropo-sphere at solar min

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Quasi-biennial Oscillation (QBO)

• Driven by small scale wave and tropical
  circulation.
• An alternation of anomalous eastward and westward
  equatorial stratospheric winds

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QBO and solar cycle

• Mayr et al. (2006)
• the QBO serves as an amplifier of the solar
  
• influence in the lower stratosphere.
• Hines(1974)
• solar variability could influence the
• interaction between planetary waves and
• zonal mean flow.
• This interaction is affected by solar variability
  and dependent on the QBO phase.
• 50-hpa geopotential height
• solar minima low during the w QBO phase
• high during the e
  QBO phase
• solar maxima opposite relationship

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Ozone in stratosphere

• EOF First mode 45, PC 28 months
• EOF Second mode 34, PC 11-yr
• - 10 DU about 4 of mean column ozone

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Previous achievement

• Ruzmaikin and Feynman (2002)
• relation between NAM and QBO
• Ruzmaikin et al. (2004)
• patterns of climate change at the
  Maunder Minimum
• Limpasuvan et al. (2005)
• PVI and SSW
• Camp et al. (2003)
• QBO and solar cycles as leading
  modes in ozone.
• Ruzmaikin et al. (2005)
• QBO signature in the Brewer-Dobson
  circulation.
• Jiang et al. (2005)
• modeling of QBO in column O3 in the
  tropics

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• Winter stratoshperic polar vortex weaken
• Sudden Stratospheric Warming (SSW)
• temperature
• westerly zonal mean wind
• Planetary waves propagating from the troposphere
  (Andrew et al., 1987, )

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• Polar vortex intensification (PVI)
• The circumpolar wind and polar cooling
• Induced by the gradual radiative cooling under
  reduced wave activity

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Proposal
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Approach

• Observation
• Idealized models
• 1-D photochemical model (Allen et al.
  1981)
• 2-D model with simplified chemistry but
  more
• realistic transport (Yung and Miller
  1997 Morgan
• et al. 2004)
• interactive 2-D model THIN AIR (K. K.
  Tung)
• Whole Atmospheric Community Climate
  Model
• (WACCM)
• Coupled models

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Task 1 Solar variability in UV, O3 and radiative
heating

• Ozone layer is the link of sun and climate
• Ozone concentration depends on temperature
• Temperature varies according to the UV changes
  and dynamical processes (27-day range)
• Ozone connects the solar UV changes to heating
  rates and dynamics.

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Problem and Solution
1. Ozone

• Observed Ozone Variation 4 at 1-3 hPa
• Modeled Ozone Variation 2 at 5 hPa
• Model/observation comparison
• - using the SORCE solar UV flux data
• - the MLS O3 over 27-day solar
• rotation cycle.

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2. Heating Rate

• 3 DU increase in the ozone column
• - 0.3 C warming in the stratosphere
• - 10 m increase in geopotential height.
• (Camp, et al. 2003)
• - will be confirmed by MODTRAN (Moderate
  resolution Transmittance) code
• (Berk et al. 1998)
• To improve the heating rate algorithms used in
  the interactive codes.

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Task 2 Impact of Ozone changes in GCM

• Without resolved gravity waves, most models
  (WACCM) do not exhibit an accurate QBO.
• Ozone variability underestimate.
• Large difference between model and observations.
• New physical parameterizations are included.
  (travaling gravity waves, a longwave radiation
  and merged shortwave radiation parameterization)

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Extended Investigation and Perceived Impact

• To investigate the role of QBO on vortex
  intensification and breakdown
• To exam possible influences of the ENSO and
  Pacific-North American (PNA) patterns on
  evolution of the polar vortex forced by solar UV
• The simple dynamical model (SDM) could be used to
  study QBO effects and solar variability.
• The EMD method will be applied to analysis of
  data on the 11-year time scale

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Plan for proposal study and paper review

• R-L Shia introduce 2-D model, especially the
  THIN AIR.
• Xun talk about the ozone (QBO, interannual
  variability, N/SAM, )
• Fai the paper about solar cycle
• Le Kuai the paper about QBO, interaction of QBO
  and solar cycle

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Thank you!Questions