1. Solar Forcing on Climate Through Stratospheric Ozone Change Le Kuai

2. 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

3. The Statement of Problem

4. Stratosphere  Dynamical interannual variability 1) the annular modes (NAM, SAM) 2) QBO in the tropics 3) Solar cycle

5. 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

6. Quasi-biennial Oscillation (QBO)  Driven by small scale wave and tropical circulation.  An alternation of anomalous eastward and westward equatorial stratospheric winds

7. 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

8. 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 QBO 11-yr

9. 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

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

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

12. Proposal

13. 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

14. 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.

15. Problem and Solution  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. 1. Ozone

16.  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. 2. Heating Rate

17.  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) Task 2: Impact of Ozone changes in GCM

18.  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 Extended Investigation and Perceived Impact

19. 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

20. Thank you! Questions