SSI and proxy data

IUP Bremen contribution tothe SOLID project

Mark.Weber@Uni-Bremen.de

EU SOLID Project Kick-Off Meeting, Davos, Switzerland, 12-14 Feb. 2013

Content

• our institute• solar research at IUP Bremen• recent work on Mg II index• outlook on future work• SOLID SSI & proxy database

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University of Bremen/Institute of Environmental Physics

Aim: Studying the Earth system using physical methods

Institute of Environmental Physics (IUP) is part of the Physics/Electrical Engineering Department (FB1) of University of Bremen :

• Physics and Chemistry of the Atmosphere (Prof. John Burrows)o UV Satellite Data and Science Group (UVSAT, Mark Weber)

• Remote Sensing (Prof. Justus Notholt)• Physical Oceanography (Prof. Monika Rhein)• Terrestrial Physics (Dr. Helmut Fischer)

Total: 120 members

UVSAT research

• Main research area:– satellite remote sensing

(trace gas retrievals in particular ozone)

– atmospheric chemistry and dynamics

– ozone-climate interaction– solar physics

• Satellite data:– GOME, SCIAMACHY, GOME-2 – atmospheric chemistry

experiments that provide daily SSI in the UV to VIS (SCIA: NIR) spectral range

27 day signature in SCIAMACHY stratospheric ozone– different frequency analyses of

ozone

• CWT, FFT, cross-correlation

– max. cross-correlation during SC is 0.38, weaker than in prior solar cycles (see also Fioletov, 2009)

– 27d signal in ozone

• is varying and vanishes for selected 3-month periods (max correlation r=0.7)

• about a factor 2 smaller than observed in other studies and earlier solar cycles (e.g. Gruzdev et al., 2009)

blue: ozoneblack: Mg II indexDikty et al. 2010b

SCIAMACHY/GOME/GOME-2 SSI

GOME: 1995-2011SCIAMACHY: 2002-2012GOME-2: 2007-present

– Daily full solar disc measurements using diffuser

– Radiometrically calibrated before launch

– Challenges:

• instrument and platform anomalies

• UV radiation damage (deposits of comtaminants on optical surfaces)

Pagaran et al., 2011a

SCIAMACHY

GOME/GOME-2

SCIA Proxy ModelSCIAMACHY proxy model

– allows reconstruction of solar cycle change in SSI

– assume that magnetic surface activity are responsible for irradiance variations (Fligge et al., 2000)

– assume that solar rotation changes scale up to solar cycle scale

– Parameterization of SCIAMACHY SSI changes in terms of scaled solar proxies, here Mg II index (faculae brightening) and photometric sunspot index PSI (sunspot darlening)

– similar approach: Lean et al., 1997, 2000

SCIAMACHY SSI at a reference date

Mg II index PSI index

piecewise polynomials (degradation, anomaly corrections)Scaling parameters derived

from several solar rotations

Mg II index

PSI index

Pagaran et al., 2009

SSI solar cycle changes – Comparisons of SSI changes during descending phases

of SC 21-23• SCIA proxy model (Pagaran et al., 2009,2011b)• NRLSSI model (Lean 2000)• SATIRE model (Krivova et al. 2009)• Deland & Cebula UV composite• SIM/SORCE and SUSIM observations

– SIM changes during SC 23 four times larger than the models and doubled the changes of SUSIM and UV composite during SC 22• challenges the validity of models assuming solar

surface magnetic activity as a primary source of SSI changes

• large impact on atmospheric heating rates (Calahan et al. 2010, Haigh et al. 2010) and mesospheric ozone (Merkel et al., 2011)

Pagaran et al., 2011b

2004/01 minus 2007/01 (not a full solar cycle)

Ermolli et al., 2012

Mg II index from SCIAMACHY/GOME/GOME-2

• Mg II core-to-wing ratio near 280 nm– Correlates well with UV and

EUV SSI changes (Deland and Cebula 1993, Viereck et al., 2001)

– insensitive to instrumental degradation (to first order) (Heath & Schlesinger 1986)

– composites available from multiple sensors

– used for UV SSI reconstruction and degradation corrections

Updated composite Mg II index

• Unusually low activity in SC 24

• Also seen in F10.7 cm flux

www.iup.ui-bremen.de/gome >> Solar Activity

Future plans on solar research (beyond SOLID)

Project SCIASOL as part of the BMBF Priority Programme ROMIC (‘Role of the Middle Atmosphere in Climate’)

• Degradation correction to SCIAMACHY SSI

• Recalibrated SSI datasets from GOME/SCIAMACHY/GOME-2 (240-800nm)

Updated datasets for SOLID

New degradation correction for SCIAMACHY

• From measurements using various solar light and WLS paths in SCIAMACHY and an optical throughput model layer thicknesses of decontaminants on mirror/diffuser surfaces are fitted– ASM mirror– ESM mirror– ESM diffuser– WLS internal mirror

White Light Source

IUP contribution to SOLID

• main contribution to WP2 (irradiance data exploitation) – Collecting/updating SSI and proxy data database (Task 2.1)

• Mg II index• Ca II index• Recalibrated GOME/SCIAMACHY/GOME-2A/GOME-2B

– Assessment of SSI & proxy data error analysis incl. long-term stability (Task 2.2)

– Composite SSI data (mainly UV) merging, gap filling, and error analyis (Task 2.5)

– Recommendations on 1) exisiting SSI data and 2) future SSI missions (Task 2.6)

Mg II and Ca II emission

• x

–Ca II emission core not spectrally resolved –Does Ca II provide additionally

information (not already contained in MgII)?

SSI database (discussion)Structure of database

– data storage• which data to store– ‚reference‘ SSI data (‚single spectra‘, e.g. Hall & Anderson, Kurucz, Nickel &

Labs, Shuttle-Atlas‘, rocket data, Wehrli composite)– SSI timeseries (SBUVs, UARS, ENVISAT, SOHO,…)– proxy timeseries (F10.7, Lya, MgII, CaII, PSI, sunpsots,….)– New datasets from/during this project– primary literature to the data (pdf‘s)

• Wavelength range of SSI, e.g. > 115 nm, EUV: 10-100 nm– Split responsibility: EUV: ROB, UV/VIS/NIR: UBre

• common file format• web interface to data/visualisation?• digitalisation of data?– Web page (how to present the database/documentation/quality assessmesnt)– Links to other databases (e.g. LASP LISIRD)– Property rights? restricted to the consortium initially– Updates (‚living database‘)– public outreach

SSI timeseries from space

Request for SOLID partners: • Provide a list of SSI and/or proxy data he/she has access to by contacting

chehade@iup.physik.uni-bremen.de • useful information: link to data or size of data file(s), data format, primary

reference to data (PDF)• Will send out questionnaire for data and provide ftp server for data

dumping

Ermolli et al., 2012

List of SSI missions (>115 nm)

European missions