Solar irradiance variability on hourly to decadal scale from SCIAMACHY and its impact on middle atmospheric ozone and

ozone-climate interaction

M. Weber, H. Bovensmann, J.P. Burrows, C. von Savigny, and J. Skupin Institute of Environmental Physics, University Bremen, Bremen

Proposal submitted to DFG for funding within CAWSES (Climate and Waether of the Sun-Earth System)

Schwerpunktsprogramm

Mark.Weber@uni-bremen.de

www.iup.physik.uni-bremen.de

DFG CAWSES SPP Workshop, Bornheim, 25-27 Jan 2005

SOLOZON

Overview

climate change

SCIAMACHY, GOME ...

solar irradiance

solar proxies

ozone and other trace gases

chemistry &

transport

temperature&

dynamics

solaractivity

New scientific questions

What can we learn about vis/nir spectral solar variability on short-term time scales from hours to solar rotation period?

What are suitable VIS/IR proxies for solar VIS/IR and TSI variability?

How do the solar proxies for UV and vis/NIR on hourly to monthly time scales correlate with corresponding changes in mesospheric and stratospheric ozone?

Can we detect a first sign of ozone recovery due to the turn around in the stratospheric halogen loading or is it related to changes in tropospheric forcings, dynamics, and solar forcing?

New scientific questions

What can we learn about vis/nir spectral solar variability on short-term time scales from hours to solar rotation period?

WP1: SCIAMACHY solar irradiance variability

What are suitable VIS/IR proxies for solar VIS/IR and TSI variability?

WP2: Solar activity proxy indicator from SCIAMACHY

How do the solar proxies for UV and vis/NIR on hourly to monthly time scales correlate with corresponding changes in mesospheric and stratospheric ozone?

WP3: Solar variability in ozone up to the mesopause

Can we detect a first sign of ozone recovery due to the turn around in the stratospheric halogen loading or is it related to changes in tropospheric forcings, dynamics, and solar forcing?

WP4: Ozone-climate-sun interaction

I SCIAMACHY solar irradiance variability

Sciamachy spectral range 220-2380 nm

About fifteen spectra per day (~1.5 hrs)

First routine space observation (along with SIM/SORCE) of VIS to NIR that contributes 70% to the total solar irradiance (TSI, „solar constant“) variability

Continuation of UV irradiance montoring (SBUV, SUSIM, GOME,SBUV2, SCIAMACHY,...)

Proposed work:

Investigate UV/vis/NIR irradiance variability from hourly to solar rotation period (27d)

Comparison with solar irradiance reconstruction models (SOLIVAR, PI Solanki)

Skupin et al. 2004

II Solar activity proxy indicator from SCIAMACHY

Mg II index is an excellent solar activity proxy for UV irradiance variation down to 30 nm (Viereck et al. 2001)

longterm time series starting in 1979 (SBUV/ SUSIM/ GOME)

SCIAMACHY has high senstivity (order of 10-3) for irradiance variation at visible wavelengths

Proposed work:

Search for suitable vis/NIR and TSI solar proxy

Extend and continue SCIAMACHY Mg II/Ca II index time series

Homogenisation of longterm composite Mg II index

500nm

280 nm

Skupin et al. 2004%

Update from Weber 1999

III Solar variability in ozone up to the mesopause

SCIAMACHY data source

retrieval of upper atmospheric ozone (30-65 km) using Hartley band UV wavelengths (Rohen et al. 2004)

ozone information are derived for higher altitudes (50-90 km) using the O2(

1)

dayglow emission at 1.27µm (SICMA, PI Sinnhuber)

lower stratospheric ozone, NO2,… (v. Savigny et al. 2004) and total ozone (Weber et al., 2004)

Proposed work

Study short-term variability of upper stratospheric and mesospheric ozone linked to solar proxies (up to 27d periods)

SCIAMACHY

SCIAMACHY-MIPAS V4.6.1comparison (434 profiles)

Rohen et al. 2004

IV Ozone-climate-sun interaction

What are the causes of the rapid increase in NH ozone since mid nineties?

Are recent increase in eddy heat flux (HTF, tropospheric wave forcing) part of natural variability or related to climate change?

ozone recovery due to starting decline in effective stratospheric halogen loading still premature

Proposed Work:

Extend analysis to height-resolved ozone (SBUV/

SAGE/SCIAMACHY/GOME2)

Add more years (towards solar minimum) to better disentangle solar

activity-dynamics-climate coupling in total ozone and ozonn profiles

Dhomse et al. 2005

Outlook for future work

Work in Phase 2 (Years 3 and 4):

Solar irradiance variability investigation and continuation of ozone trend

evaluation during solar minimum condition

Solar variability in high altitude backscattered limb spectra using single

scattering radiative transfer calculation for atmospheric corrections (very

short time solar variability)

implementation of UV/vis irradiance variability in our 2D and 3D chemical

transport models and scientific case studies

Combined interpretation of upper atmospheric temperatures and ozone

variability to changes in the spectral solar irradiance.

Relation to themes in CAWSES

Characterisation of variable solar forcing thru electromagnetic radiation

Solar influence on atmospheric temperature, dynamics and chemical composition

Solar activity – climate interaction

Collaborations

CAWSES Projects:

U. Langematz, Freie Universität Berlin, ProSECCO

J. Notholt, University of Bremen, SACOSAT

K. Pfeilsticker, University of Heidelberg, ABSOLAR

C. von Savigny, University of Bremen, SCIA-STOVE

S. Solanki, MPI für Sonnensystemforschung, SOLIVAR

M. Sinnhuber, University of Bremen, SICMA

Provision of updated solar proxies and írradiance variabilities

Mesospheric ozone from SCIAMACHY

Comparison to solar irradiance variability reconstruction

solar irradiance calibration

External:

NRL (Floyd), NOAA (Viereck, Puga, Weatherhead), NASA (Hilsenrath, Janz), AWI Potsdam (Rex)

Requested resources

Personnel: Two scientists (2 X BATIIa)

solar variability (1 scientist, WPs 1 and 2)

ozone-sun-climate interaction (1 scientist, WPs 3 and 4)

Duration and start of project:

Start: July 2005

Phase 1: 2005-2007 (2 years)

Phase 2: 2007-2009 (2 years)