On the stability
of SSI records
Matthieu Kretzschmar
Thierry Dudok de Wit, Micha Schoell
LPC2E, CNRS & University of Orléans, France
On SSI record stabilities, M. Kretzschmar, Sun-Climate Symposium, Savannah, Nov. 2015
Content
Surface magnetic field
NRLSSI2
SORCE/
Sim
UARS/
Susim
ISN
NLTE below 300nm
faculae, sunspot
Mg II
UARS/
Solstice
NOAA/
SBUV
f10.7
SORCE/
Solstice
Ca K
1D model atmosphere
network, ER
SATIRE
What about modeling the Mg II profile?
On SSI record stabilities, M. Kretzschmar, Sun-Climate Symposium, Savannah, Nov. 2015
Outline
❖What Solar rotational variability can tell us
about longer trend variations in SSI records ?
❖Can we provide a common measure of the
stability of SSI records ?
I( , t) = I0 ( ) + Ist ( , t) + Ilt ( , t) >
court. T. Woods
On SSI record stabilities, M. Kretzschmar, Sun-Climate Symposium, Savannah, Nov. 2015
Solar rotational variability
✓ Well measured !!
I( , t) = I0 ( ) + Ist ( , t) + Ilt ( , t) >
I( , t) = a0 +
X
ai (Pi (t)
< Pi (t) >⌧ ) +
i
➡ I( , t)
< I( , t) >⌧ =
X
bi < Pi (t) >⌧
i
X
ai (Pi (t)
< Pi (t) >⌧ )
i
NB:IF scaling does not change between rotational and
« slow » change, then
X
I( , t) = a0 +
ai Pi (t)
i
On SSI record stabilities, M. Kretzschmar, Sun-Climate Symposium, Savannah, Nov. 2015
Ex: UARS/Solstice @ 180nm
data
model HF
fitted with DSA & MgII
On SSI record stabilities, M. Kretzschmar, Sun-Climate Symposium, Savannah, Nov. 2015
Ex: UARS/Solstice @ 180nm
data
model HF
data - model HF
fitted with DSA & MgII
On SSI record stabilities, M. Kretzschmar, Sun-Climate Symposium, Savannah, Nov. 2015
data - model HF
[W/m2]
Ex: SORCE/Solstice @ 245nm
SORCE/SOSLTICE @ 245nm
Strong decrease
annual variations
Time [day]
fitted with DSA & MgII
On SSI record stabilities, M. Kretzschmar, Sun-Climate Symposium, Savannah, Nov. 2015
Solar rotation viewed by different instrument
data
model HF
fitted with DSA & MgII
On SSI record stabilities, M. Kretzschmar, Sun-Climate Symposium, Savannah, Nov. 2015
Solar rotation viewed by different instrument
data
model HF U/SOSLSTICE
model HF U/SUSIM
model HF SORCE/SOLSTICE
fitted with DSA & MgII
On SSI record stabilities, M. Kretzschmar, Sun-Climate Symposium, Savannah, Nov. 2015
125nm-150nm
125nm-150nm
150nm-180nm
241nm-260nm
1st part conclusion
✓
What is the reason when observed/model SSIs
variations differ significantly from their solar rotation
prediction ?
✓
Solar rotational signals are consistent between
instruments and give the same SC variability.
✓
SATIRES larger cycle variability (in particular, SC 22
min and max and SC 24 min) wrt others looks partly
caused by larger rotation modulation. Depends on
wavelengths.
On SSI record stabilities, M. Kretzschmar, Sun-Climate Symposium, Savannah, Nov. 2015
ok.
Model 1: Trend Differences
Other effects might exist.
Each spectral me series of each datasets is ed
Gowith
for
a me
3 components
model
a two
scale linear component
model
SSI time series
LF (>108 days) proxies
HF (<108 days) proxies
+ε
Model 1: Trend Differences
best model coefficients (lsq sense) determined for each λ
Each spectral me series of each datasets is ed
with a two me scale linear component model
On
SSItime
record
stabilities,LF
M. (>108
Kretzschmar,
Sun-Climate
Savannah,
days) proxies
HFSymposium,
(<108 days)
proxies Nov. 2015
SSI
series
Estimating stability
Residuals
Irradiance [W/m2]
UARS/SOLSTICE @ 180nm
On SSI record stabilities, M. Kretzschmar, Sun-Climate Symposium, Savannah, Nov. 2015
Estimating stability
UARS/SOLSTICE @ 180nm
On SSI record stabilities, M. Kretzschmar, Sun-Climate Symposium, Savannah, Nov. 2015
Estimating stability
UARS/SOLSTICE @ 180nm
On SSI record stabilities, M. Kretzschmar, Sun-Climate Symposium, Savannah, Nov. 2015
Estimating stability
UARS/SOLSTICE @ 180nm
The stability is defined as s( , t) =| aobs ( , t)
abestf it ( , t) |
On SSI record stabilities, M. Kretzschmar, Sun-Climate Symposium, Savannah, Nov. 2015
Estimating stability
UARS/SOLSTICE @ 180nm
Proxy ?
DSA, Mg II
The stability is defined as s( , t) =| aobs ( , t)
abestf it ( , t) |
On SSI record stabilities, M. Kretzschmar, Sun-Climate Symposium, Savannah, Nov. 2015
Estimating stability
UARS/SOLSTICE @ 180nm
Proxy ?
DSA, Mg II, radio flux at 3.2cm, 10.7cm, 15cm, and 30cm
On SSI record stabilities, M. Kretzschmar, Sun-Climate Symposium, Savannah, Nov. 2015
Hypothesis behind
What can not be reproduced by a two time scales and six
proxies model is more uncertain !
Cons: this multi parameters model can reproduce trends and
non solar behavior to a certain degree. It is permissive.
On SSI record stabilities, M. Kretzschmar, Sun-Climate Symposium, Savannah, Nov. 2015
Results
On SSI stability, M. Kretzschmar, 3
UARS/
SOLSTICE
• In
% / yr
• In
% of solar cycle
variation / yr
On SSI stability, M. Kretzschmar, 3
UARS Overview
Stability [%/yr]
Irradiance [W/m2/nm]
•
Stabilities are averaged over the mission lifetime
On SSI stability, M. Kretzschmar, 3
SME & SBUV 9
SBUV9
SME
On SSI stability, M. Kretzschmar, 3
SME & SBUV 9
SBUV9
SME
On SSI stability, M. Kretzschmar, 3
SSI datasets Overview
SME
SBUVs
UARS
TIMED
SORCE
SDO
➡
Best range is in the UV below 220nm: no surprise !
On SSI stability, M. Kretzschmar, 3
CONCLUSION
✓
Strength of stability as computed here:
✓ Determine the SSI/proxy relationships for each time series, in a
permissive way
✓ Allows to quantify (weight) in the same way most of the doubts on all
instrument time series
✓
Weakness of stability as computed here:
✓ depending on number of proxies used, can reproduce instrumental
features)
✓
Stability can be used as weights for composite.
✓
SSI variations trustable up to about 220-240nm
✓
SORCE trend in the visible canNOT be reproduced by combination of
proxies
Used in this work: SSI datasets corrected for outliers and gaps, see Scholl et al.,
On SSI record stabilities, M. Kretzschmar,2015
Sun-Climate Symposium, Savannah, Nov. 2015