On the Connection between Solar Spectral Irradiance (SSI), Planetary Wave Drag and the Zonal-Mean Circulation

Transcription

1 On the Connection between Solar Spectral Irradiance SSI, Planetary Wave Drag and the Zonal-Mean Circulation erry Nathan Atmospheric Science Program University of California, Davis John Albers Atmospheric Science Program University of California, Davis Eugene Cordero Department of Meteorology San Jose State University OULINE Goal A New Pathway Model and Equations SSI and Oone Heating Conceptual Framework Connection between SSI and PWD SSI-Modified Wave-Mean Flow Interactions Conclusions SORCE Meeting 8, Santa Fe

2 GOAL o understand how variations in solar spectral irradiance SSI are communicated to the onal-mean circulation via the planetary wave drag PWD induced by longitudinal variations in oone. his study builds on: Nathan,. R., and E. C. Cordero, 7: An oone-modified refractive index for vertically propagating planetary waves. J. Geophysical Research - Atmospheres,, D5, doi:.9/6jd7357. Cordero, E., and. R. Nathan, 5: A new pathway for communicating the -year solar cycle signal to the QBO. Geophys. Res. Lett., 3, No. 8, L885,.9/5GL3696.

3 A New Pathway for Communicating Changes in SSI to the Climate System Variations in Solar Spectral Irradiance NEW PAHWAY MORE COMPLEE VIEW Wave-Oone Pathway plus Zonal-Mean Pathway O3, u, v, w, WAVE FIELDS Longitudinal Variation in O 3 PWD O3 RADIIONAL PAHWAY INCOMPLEE VIEW Zonal-Mean Pathway U, MEAN FIELDS PWD CIRCULAION AND CLIMAE 3

4 Model Nathan and Li 99, JAS; Cordero and Nathan 7, JGR A Mechanistic Coupled Chemistry-Dynamical Model Dynamics Quasigeostrophic Forcing at lower boundary Linear mechanistic Analytical WKB Wave-Mean Flow Interaction Mechanistic: Holton-Mass 976 with oone transport and photochemistry Radiative-Photochemical Newtonian Cooling Oone transport Oone photochemistry Solar spectral irradiance accounted for in temperature dependent oone production / destruction Catalytic loss processes involving hydrogen, nitrogen and chlorine compounds are parameteried by adjusting pure oxygen reaction rate Hartman 978 Oone shielding effect 4

5 SSI and Oone Heating 8 Variations in SSI over the Solar Cycle 4.5 Adapted from From Lean 997 Ann. Rev. Astron. Astrophys. Oone Heating Rates Adapted from Strobel 978 JGR 5

6 6 Model - Governing Equations = Q c x q x u t e, -. / = 6 F y y Q c u u c t u R v L = R R d Q Wave Equations Zonal-Mean Equations R H f d S = H f d Q = S w v y w y v t = = S w y x x u t = R R R d S HEAING/COOLING Wave and mean PRODUCION/ DESRUCION Wave and Mean OZONE Wave and mean QGPVE ZONAL MEAN FLOW Plus Mean-Meridional Circulation Equation

7 Conceptual Framework he planetary wave-induced oone heating wave-oone feedback process pivots on longitudinal variations in the wind and temperature fields producing longitudinal variations in the oone field. u, O 3 Wave Perturbation in Oone v, w, Vertically Propagating Wave 7

8 he phasing and structure of the wind, temperature and oone fields -- which are coupled to each other as well as to the background distributions of wind, temperature and oone -- directly affect the planetary wave drag PWD, processes vital to the driving of the onal-mean circulation. O PHASE DIFFERENCE Any perturbation to the wave-oone feedbacks, natural or human-caused, will be imparted to the onal-mean field. 8

9 Variations in Solar Spectral Irradiance Connection between SSI and PWD Zonal-Mean Variations in Oone Heating RADIIONAL PWD Planetary Wave Drag Longitudinal Variations in Oone Heating NEW Why is PWD so important? PWD F EP-Flux Divergence Zonal-Mean Flow Residual Mean Meridional Circulation, Vertically Propagating Wave F = F y j F k momentum flux heat flux 9

10 Propagation, Attenuation and PWD d A d m A = EVANESCEN m < m ; u,, O3,... = Complex Refractive Index REFLECING SURFACE PROPAGAING REGION m = m > Re m ~ propagation Im m ~ attenuation How are propagation and attenuation related to PWD? Nathan,. R., and E. C. Cordero, 7: An oone-modified refractive index for vertically propagating planetary waves. J. Geophysical Research - Atmospheres,, D5, doi:.9/6jd7357. Cordero, E., and. R. Nathan, 5: A new pathway for communicating the -year solar cycle signal to the QBO. Geophys. Res. Lett., 3, No. 8, L885,.9/5GL3696.

11 WKB Solution for EP-Flux Divergence, Z A B [/ ˆ,. ˆ ] = [, ]exp i m dz - exp ikx sin ly cc SSI-Modified Vertical Wavenumber Refractive Index m = m 3 r i m 3 i Propagation Attenuation SSI-Modified Planetary Wave Drag F m imr A exp mid Zonal-Mean Flow Equation u fv = F = FSSI t Nonlinear function of SSI

12 Oone-Modified Downward Control Residual Vertical Velocity Downward Control w =, f, F y X d F o what extent is the divergence of Eliassen-Palm flux i.e., PWD affected by the planetary wave induced oone heating? Downward influence from a radiative perturbation can only arise through changes in reflection and meridional propagation of planetary waves. Adapted from Holton 4 Shepard and Shaw 4; JAS

13 3 Oone-Modified Propagation and Attenuation { advection oone Meridional r advection oone Vertical NC r y k u fh M H f uk H m Z m, -, Ã CLASSIC REFRACIVE INDEX LOWER SRAOSPHERE DYNAMICAL CONROL { Advection Oone Meridional advection oone Vertical NC i i y k m u H f H f uk M m Z m, -, UPPER SRAOSPHERE PHOOCHEMICAL CONROL { 443 Cooling cal Photochemi NC r r R uk M m Z m { 443 Cooling Photochemical NC i i H f uk M m Z m

14 Mean Zonal Mean Wind versus ime 6 km 3 km CONROL RUN [Holton and Mass 976] NO OZONE WIH OZONE WIH OZONE and SSI change over -year Solar Cycle WIH OZONE and SSI change over -year Solar Cycle NO PWD 4

15 Conclusions A more complete pathway for communicating solar cycleinduced changes in stratospheric oone to the climate system has been identified. Changes in SSI he more complete pathway incorporates the effects of SSI-induced changes in stratospheric oone on planetary wave drag PWD. he SSI-induced variations in PWD associated with longitudinal variations in oone have a significant effect on stratospheric wavemean flow interaction period and amplitude; this has implications for stratospheric sudden warmings. 5

16 Sun-Climate Focused Science eam Sponsored by NASA s s Living with a Star Program SENSIIVIY of REGIONAL and GLOBAL CLIMAE to SOLAR FORCING EAM MEMBERS erry Nathan Eugene Cordero Linton Floyd Rolando Garcia Lon Hood Charles Jackman Judith Lean John McCormack Jeff Morrill Cora Randall David Rind 6