Dear Dr Hoeksema:
In response to the message concerning the WSO data just received as part of the AGU
SPA Newsletter, I am attaching for your reference a paper that acknowledges scientific
use of the WSO data, as emphasised in your message. The data were used to provide
background material that underpinned the interpretation of Cassini IMF data obtained
during the approach to Saturn, as is indicated in the paper. We would wish to make
similar use of the data in future as the Cassini mission unfolds into the rising phase of the
next solar cycle.
May I take the opportunity of thanking you once again for the help you gave in providing
these data to us.
Regards, Stan Cowley
Prof Stanley W H Cowley
Head, Radio & Space Plasma Physics Group
Department of Physics & Astronomy Tel: +44-116-223-1331
University of Leicester, Leicester LE1 7RH Fax: +44-116-252-3555
United Kingdom Sec: +44-116-252-3563
To Whom It May Concern:
I frequently use the data products of the Wilcox Solar Observatory in my research and
strongly urge that the program continue. The coronal magnetic field maps at the source
surface are particularly useful for relating solar wind features to the heliospheric current
sheet, and several have appeared in my publications, most recently in Crooker and Webb
(2006). This publication also features a section from one of the large-scale photospheric
Crooker, N. U., and D. F. Webb (2006), Remote sensing of the solar site of interchange
reconnection associated with the May 1997 magnetic cloud, J. Geophys. Res., in press.
The data from WSO are the "gold" standard
for the long-term assessment of the large-scale
solar magnetic field. The accurate determination of
the zero-level is unique to WSO. WSO polar fields
have been (and will be for cycle 24) important for
the prediction of solar cycle strength [e.g. Svalgaard
et al. (2004) Geophysical Research Letters, Volume 32,
Issue 1, CiteID L01104]. The mean field signal is
still not well understood, but its long-term behavior is
probably important for the understanding of the sources
of the IMF [e.g. Kotov et al. Solar Physics, v. 209, Issue 2,
p. 233-245 (2002)]. The "saturation" factor problem is
also unresolved: The magnetic fields measured at each
observatory are all different, but for each observatory
a factor (or function) exists to make all measurements
agree. The cause of this is unknown. It is important to
let WSO operate at least until the end of cycle 24. At
that time, we may have enough data overlapping with
SOLIS that we can properly interprete the legacy of
WSO data back to 1976. The value of long-term
data is often degraded by termination of the observations
without sufficient overlap with newer data. The Greenwich
sunspot areas come to mind. ACRIM solar irradiance is
Date: Tue, 30 May 2006 11:39:34 -0700 (PDT)
From: Janet Luhmann <firstname.lastname@example.org>
Reply-To: Janet Luhmann <email@example.com>
Subject: CISM use of WSO
Cc: firstname.lastname@example.org, email@example.com,
firstname.lastname@example.org, email@example.com, firstname.lastname@example.org,
Re: Response to SPA news item on uses of WSO
WSO is one of the primary solar magnetogram providers for
our solar/heliosphere modeling activities within CISM (the
Center for Integrated Space Weather Modeling)- an NSF Science
and Technology Center led by Jeff Hughes at Boston U.
MHD models of the solar corona, including those of CISM, are
just coming of age in terms of regular use and practical
applications. Simulations of the solar wind are coupled to
these coronal models, and depend on their accuracy. Full-disk
solar magnetograms from WSO have been one of the main sources
of the critical synoptic map boundary conditions used in CISM
models. In particular, they are an option in the CORHEL
community user-oriented version of the CISM corona and solar
wind model which is archived and provided for general users
at the CCMC (Community Coordinated Modeling Center) at
Goddard Space Flight Center. The NOAA SEC (Space Environment
Center) also uses CISM models for assessing upgrades to their
space weather prediction capabilities. STEREO mission, to launch
this year, will make heavy use of the magnetograph-based models
for its multipoint data interpretation.
While there are a few other sources of magnetograph-derived
synoptic maps, WSO is one of the longest-lived and most consistent
providers. These data can be used for a host of solar cycle studies
of the corona and solar wind, as well as providing the basis for
calibrating newer magnetographs, such as the SOLIS instruments at
NSO and the upgraded GONG instruments. The WSO staff does an
exceptional job of generating and providing, via website, useful
products relating to everything from the latest heliospheric
current sheet geometry to the ongoing solar cycle changes in
the solar polar fields. To lose this stable and reliable solar
magnetograph resource would be akin to losing something like the GOES
spacecraft series- it is something we have all grown to use and
depend on, and is irreplaceable in terms of its benefit to current
We hope that you will find a way to maintain the WSO magnetograph
facility and continue support for its operation and data provisions.
It would be a shame to lose its benefits at a time when it is becoming
more and more widely used and exploited given the high level of
in the solar and heliosphere modeling and space weather communities,
Janet Luhmann, on behalf of CISM solar modeling members
Yes, we do use WSO observations in our work. We use them to
compare with MWO and NSO observations. Over the years, one
of the observatories occasionally has a problem. We use them
for long-term consistency. Here, spatial resolution is not
a factor. The important quantity is consistency for comparing
the fields of one cycle with another. We also use the mean
field observations, again looking for the long-term variation.
As we get into more sunspot cycle studies and studies of the
dynamo, the WSO observations will be increasingly important.
I could go on, but I will let my colleague Yi-Ming continue...
Hi -- I am writing in support of continuing the Wilcox Solar Observatory synoptic program. WSO
observations were integral to my thesis work, and the citations listed below directly or indirectly
depended on these data. Despite the fact that there are current and pending magnetic field
observations available which have higher spatial resolution and better time coverage, there
remains a set of important scientific questions regarding the large-scale, slowly-changing Sun for
which WSO data are ideal. WSO provides a continuity of data which is essential to understanding
solar changes on time scales on the order of solar cycles. Having used WSO data while just
starting out as a graduate student, I can also testify to the ease of use of the data: the spherical
harmonic coefficients were particularly useful data products for me.
So, please don't turn it off!
S. E. Gibson, Global solar wind structure from solar minimum to solar maximum: Sources and
evolution , invited review paper for Proc. of the 34th ESLAB symposium, ESA publications
S. E. Gibson, D. Biesecker, M. Guhathakurta, J. T. Hoeksema, A. J. Lazarus, J. Linker, Z. Mikic,
Y. Pisanko, P. Riley, J. Steinberg, L. Strachan, A. Szabo, and B. J. Thompson, The Three-
Dimensional Coronal Magnetic Field During Whole Sun Month, ApJ, 520, 871, 1999.
S. E. Gibson and P. Charbonneau, Empirical modeling of the solar corona using genetic
algorithms, JGR, 103, 14511, 1998.
S. Gibson and P. Scherrer, Supergranule power leakage through an observing mask, in IAU
Symp. 181: Sounding solar and stellar interiors (Poster volume, eds. J. Provost & F.-X. Schmider,
S. E. Gibson , F. Bagenal, D. Biesecker, M. Guhathakurta, J. T. Hoeksema, and B. J. Thompson,
Modeling a simple coronal streamer during Whole Sun Month, Proc. of the Fifth SOHO
WORKSHOP, ESA SP-404, 319, 1997.
S. E. Gibson, F. Bagenal, and B. C. Low, Current sheets in the solar minimum corona, JGR, 101,
S. E. Gibson and F. Bagenal, Large-scale magnetic field and density distribution in the solar
minimum corona, JGR, 100, 198651, 1995.
F. Bagenal and S. Gibson, Modeling the large-scale structure of the solar corona, JGR, 96, 17663,
1991. Dear Todd et al.:
The WSO data continue to be of great use in my research. A recent example
is the use in the paper by Bemporad et al. (2003). However, this does not
reflect our continuous use of the data on a regular basis as an aid to
interpretation of the state of the large scale corona. There is no similar
data set for us.
Our use of the data includes the source surface models and, more recently,
use of the source surface coefficients in a developing study. The utility of the
(1) Its continuity over a very long interval.
(2) Its coverage of the entire Sun, in a synoptic data set.
(3) The ease of access, with no additional manipulation being required.
I expect to utilize the WSO data in the coming several years as an important
piece of information for developing a 'reference heliosphere' at the time of
the Voyagers' encounter with the heliosheath.
Related data sets from SOHO, the upcoming Solar-B mission, and SDO to be
launched in 2008 do not meet the same requirements. Those data are focused on
high resolution and fine scale structure studies. They do not easily address the
large-scale corona and the state of the heliosphere over multi-solar cycle
The WSO data thus continues to be of value to a large community.
- Steve Suess
Bemporad, A., G. Poletto, S. T. Suess, Y. K. Ko, S, Parenti, P. Riley,
M. Romoli, and T. Z. Zurbuchen, Temporal evolution of a streamer complex:
coronal and in situ plasma parameters, Astrophys. J., v593, 1146-1163, 2003.
Steven T. Suess (Steven.T.Suess@nasa.gov)
NASA Marshall Space Flight Center
National Space Science & Technology Center / Solar Physics
Mail Code XD12
Huntsville, Alabama 35812-9999 USA
ph. 256-961-7611, fax 256-961-7216
I found the Wilcox solar data very useful in compiling an analysis of the
effects of differential rotation on the solar magnetic field -- reference:
author = "Berger, M. A. and Ruzmaikin, A.",
title = " Magnetic helicity production by differential rotation",
journal = jgr,
year = 2000,
volume = 105,
pages = "10481--10490",
annote = " "
I would hope sometime in the future to extend the analysis to the most recent
Very best Wishes
Professor Mitchell Berger email@example.com
Mathematics, University College London +44 (0) 20 7679 2835
Gower Street London WC1E 6BT
+44 (0) 20 7679 2839
I don't know the cost of continuing the Stanford Wilcox observations, but I and many
others regard the PFSS synoptic maps as a highly valuable asset, with the long-term
continuity being an important factor here. In some ways this is like the valuable archival
data base compiled by IMP-8, which was enough to find ways to keep it operating in a
limited capacity long after its nominal lifetime. As you know, Nancy Crooker and I have
found the Stanford SS maps very valuable in our work where we look for changes in the
1 AU inward/outward field polarities to compare with the solar-wind heat flux signatures
for magnetic topologies. We hope to do more work with Nariaka Nitta to trace SS fields
down to their photospheric origins for long-lived and transient structures. Then of course
there are the important solar wind predictions using the nonradial expansion of open field
models from the SS maps, of great value to the space weather community. I am not
knowledgeable about the big question of inter-observatory field calibrations, but maybe
the Wilcox observations play an important role there, as well.
Maybe the Wilcox 3-arc min data are not really needed for the SS maps, but if not, then
we would want to know what new magnetograph data are replacing them and how that
impacts the SS maps. The Wilcox observations will be terminated at some future time,
we suppose, but it would be good to know just what data sets will replace them and what
the implications are for continuing the SS maps. I am concerned, but the uncertainty of
the consequences leaves me somewhat ambivalent here.
I hope this is useful for you in making the case (or not) for continued Wilcox
This e-mail is in support of the continuation of WSO observing program.
About a month ago, or so, I began to use WSO data, more specifically,
the coronal maps (WSO-R250*gif) computed from the WSO magnetic field
maps. There is no publication yet since this is a new study in progress
and about 26 WSO magnetograms-coronal images pairs (all are gifs) are
used so far to study orientations of the magnetic fields in the CME
source region, coronal and interplanetary ejecta.
I did not yet notify you about the data usage as the WSO Data Policy
requires, mainly because, again, this is a work in progress. I'll most
certainly send you a copy of a study report and include a proper credit
in a publication.
If you would like to know more details on what I do, please, let me
I'd be happy to show you preliminary results and figures.
On June 23 I'll be visiting HEPL for one day to attend the calibration
review meeting and if it is convenient for you, I'd be happy to talk to
you about this during this visit.
Big Bear Solar Observatory
40386 North Shore Lane
Big Bear City, CA 92314-9672
909.866.5791 x 35
Hi Todd et al,
I would like to add a little weight to the argument for keeping WSO running if possible.
We have found it very valuable for comparing with interplanetary scintillation
because it gives a reliable indication of the location of the neutral sheet a the source
This has become more important to us as we try to compensate for the line of sight
in the IPS observations by modeling the full line of sight. The model requires the electron
density, not the magnetic field, but the WSO neutral sheet defines the average location of
the highest density slow wind as well as does a WLC. So we find it very valuable to have
both. The Lasco coronagraphs have greatly improved the density measurements but there
has not been a corresponding improvement in the magnetic neutral line estimate.
Although I have not been doing as much IPS recently, this work has been continued by
group at Aberystwyth in Wales, involving Andy Breen, Richard Fallows and others. They
continue to use the modeling techniques that we developed and they find WSO data very
Coles, Grall, Klinglesmith and Bourgois, JGR 100, 17069, 1995
Coles, Sp.Sc.Rev. 72, 211, 1995
Grall, Coles, Klinglesmith, Breen, Williams, Markkanen, and Esser, Nature 379, 429,
Coles, Astrophys and Space Sc. 243, 87, 1996
Response to the question on continuation of WSO synoptic program.
As a user (see for example the paper Ruzmaikin, J. Feynman, M. Neugebauer and E.
Smith, Preferred solar longitudes with signatures in the solar wind, J. Geophys. Res, vol
106, 8363, 2001) I vote for continuation of the WSO Program.
The availability of higher resolution solar magnetic observations, does not jeopardize the
usefulness of continuing the Wilcox Solar Observatory synoptic program. First, there are
applications, which do not require fine resolution but rather global averaged maps,
similar to the fact that many engineering applications do well with Newton laws and do
not need relativity. Second, in addition to the direct data, the WSO provides a valuable
amount of processes data, such as harmonic coefficients and coronal filed extensions,
which are extremely useful in doing research.
Principal Scientist at Jet Propulsion Laboratory
California Institute of Technology.
Dear Todd and Colleagues,
I am sorry to hear that Wilcox is in danger of being shut down.
There may indeed be reduced need for low spatial resolution
magnetograms with new instruments coming online. However, in at
least one respect Wilcox data are invaluable, namely to help
determine long-term trends and to constrain models of the evolution
of the magnetic field, e.g., the total magnetic flux determined at
low resolution (in particular its secular evolution, which is
central for producing secular trends in irradiance and other
quantities that may affect our climate). Unfortunately, neither Kitt
Peak nor Mt Wilson data appear to have the stability to give
reliable results on their own and Wilcox data are quite
indispensable. Now, the Kitt Peak SPM may be more stable than the
old 512-channel magnetograph, but the large gap between the end of
data taking by this instrument and the time at which SOLIS data
started being regularly recorded has once again demonstrated the
importance of Wilcox data. I would strongly urge you to continue
gathering data at WSO until it is clear that SOLIS is providing
stable results for the total magnetic flux. Maybe the maximum of the
next cycle may be a better time to reconsider the future of WSO (HMI
will be running and SOLIS should have provided enough data to get an
idea if there are any drifts), although I would urge you to run WSO
for an even longer time. There have been too many examples of long-
term solar records being stopped at highly inopportune times
(Greenwich observatory's end of the sunspot program in 1976 being a
particularly sad example). Unfortunately, space missions cannot
replace the ground-based instruments due to the limited lifetime of
We have recently submitted a paper (Wentzler, T., Solanki, S.K.,
Krivova, N.A., Froehlich, C., 2006, Astron. Astrophys. submitted) in
which Wilcox data play an important role (for exactly the reason
Similarly, Wilcox data are also used to constrain models of the
total and open magnetic flux and irradiance in a paper that we are
currently writing and hope to submit within the next month or two
(Balmaceda, L., Krivova, N.A., Solanki, S.K., Schuessler, M., 2006,
Astron. Astrophys. to be submitted).
We plan to use WSO data for further such analyses in the near
Reply on the question: Continuation of Wilcox Solar Observatory Program ?
(SolarNews, Volume 2006 Number 12)/ Dr. Mikhaylutsa V.P.
Dear Dr. Todd Hoeksema!
I should like to state my point of view on such old and important question as: Are the
solar large-scale observational data important today for investigation of solar behavior?
My 30-year experience as solar researcher has given me the understanding of
importance of such kind of solar observations. Really, from common physical point of
view, the formation and evolution of large-scale characteristics of nonlinear dynamical
system are determined by small-scale ones if the energy of system is transported strongly
from the small-scales to the large-scales. I believe that for the Sun it is the open question
Not concerning unconditional importance of these observations for tracking the
evolution of the Sun's polar and large-scale photospheric field, routinely and reliably
modeling the coronal magnetic field at the source surface, forecasting solar wind
conditions etc., I specify the following example: Who knows, what is the origin of the
sectoral-hemispherical asymmetry in solar behavior?
This surprising phenomenon appears only in large-scale distributions of facular points
on the quiet solar photosphere...(Solar Phys. 2001, Vol.199, pp.13-21).
Thank you for attention,
Dr. Mikhaylutsa V.P.
This email is in response to the question about WSO continuation.
I may not have fully acknowledged the usefulness of WSO and staff, although I hope I have, in a
number of papers (which are really helpful to NASA), in making long term predictions of the solar
cycle (and updates I supply to NASA at Goddard), based primarily upon WSO observations. I
shall put some of the references below, but I know the list is not complete as I have not updated
my vita recently, etc... I know though that I, and recently Svalgaard, used WSO observations to
help predict the next cycle's activity levels. WSO may not have the smallest observing window,
however, I find that the stability of the observations is vastly superior to other observatories where
there is more noise in the data, through numerous "upgrades", (which really represent changes to
their system, and make their data less reliable for long-term studies.. .such as solar activity
prediction than the WSO data.) The WSO staff are excellent researchers and their instrument is
world class, so I think it should be continued for the next few years, certainly until the next solar
I cannot think of a more valuable resource to the community than WSO ($ for $), not only with the
raw observatory data, but also the fine Work that Hoeksema, Scherrer, and others do in studies
of coronal fields, and the interaction of the Sun with the Earth, which is what the Living with a Star
program should be about. At Stanford, they also help train future generations of students on the
value of solar research, as students often operate the telescope, etc., so there are many side
benefits that do not come out in "publication lists." Below are a small sample of papers where i
have used WSO data. I know I used them for each cycle, back to '78 when we started making
forecasts of solar activity (from WSO, where the methods originated). The WSO has a long
record of drawing together excellent solar researchers who wish to work with their staff.
a.i. solutions, Inc
10001 Derekwood Lane, suite 215
Lanham, MD 20706 USA
main phone 301 949-7855 *2
cell phone: 301 221-8107
123. "Panel Achieves Consensus Prediction of Solar Cycle 23" by Jo Ann
Joselyn, et al. , EOS Transactions, AGU, Vol. 78, no. 20, pgs. 205,
124. "Forecast Update for Activity Cycle 23 from a Dynamo-Based Method”, S. Sofia, P. Fox, K.
Schatten , Geophys. Res. Lett. , VOL. 25, NO. 22, PAGES 4149-4152, 1998.
125. “Coronal and Interplanetary Magnetic Field Models: A Critical Commentary,” Schatten, K. H.,
AGU Monograph of Yosemite conference proceedings, 1999.
126. “Coronal and Interplanetary Magnetic Field Models”, Schatten, K. H, Solar Wind 9 conference
proceedings, Nantucket, MA., 1999.
127. “Coronal and Interplanetary Magnetic Fields: Streak lines ”, Schatten, K. H., J. Geophys. Res. , Vol.
106 , No. A8 , p. 15,833 (2000JA000102).
128. “Solar activity prediction: Timing predictors and cycle 24”, Schatten, Kenneth JGR – Space Physics,
129. “Solar Activity and the Solar Cycle” presented at COSPAR, session D - D1.1-0001, accepted for
publication in “Advances in Space Research” ASR, 2003.
130. Schatten, K., Correction to “Solar activity prediction: Timing predictors and cycle 24” JGR – Space
Phys., 2003JA009843, 2003.
131. Schatten, K., “Fair Space Weather for solar cycle 24”, GRL vol 32, L21106, 2005.
My group at SAIC uses WSO synoptic maps as boundary conditions for modeling the
large-scale corona. I strongly believe that WSO observations should continue through
the coming cycle, because they represent a continuous, WELL-CALIBRATED data set
over the greatest # solar cycles of any observatory. The emphasis on calibration is
important. For example, in trying to model the time-period 1980-2000, we found
changes in the properties of our solutions that corresponded with instrument changes at
other observatories, and did not appear when we used Wilcox data. While we certainly
take advantage of higher resolution maps from other observatories in studying
individual time periods, at the present time WSO maps are the best resource for studies
over a number of cycles. I might add that the Stanford staff is always very helpful for
working with WSO data (or MDI, for that matter).
I regularly use the data from WSO in my research. I have cited and
acknowledged the WSO data in my papers. Most of these papers were sent
to you (see the list below). I would like to comment on the usefulness
of the WSO data.
The Wilcox Solar Observatory provides for scientific community data
which represent large-scale properties of solar magnetism. Large-scale
patterns in solar magnetic fields appear clearly in the WSO
magnetograms at moderate resolution. The procedure of extrapolation of
solar magnetic field at the source surface reveals the heliospheric
current sheet, its sector structure.
The time-series of the Sun-as-a-star magnetic field measurements
quantify the global magnetic field of the Sun. This dataset is useful
to compare its changes with the Total Solar Irradiance to study the
relation between magnetic and radiative indices of the Sun. This is
also of interest to compare the cyclic behavior of the Sun with sun-
The synoptic maps of the photospheric magnetic fields as well as the
synoptic maps of the computed coronal magnetic field characterize
large-scale patterns in magnetic activity of the Sun and the temporal
behavior of the opened magnetic field. The fast rearrangements of
large-scale magnetic field sometimes result in dramatic changes in
The data from WSO complement high resolution magnetograms in a
non-redundant way. The high-precision WSO measurements provide an
independent scale to estimate long-term changes in solar and
heliospheric magnetic field which possibly affect the Earth
A. V. Mordvinov and L. A. Plyusnina, Cyclic Changes in Solar Rotation
Inferred from Temporal Changes in the Mean Magnetic Field, Solar Phys.
V. 197, 1, 2000.
A. V. Mordvinov et al. The Topology of Background Magnetic Fields and
Solar Flare Activity, Solar Phys. V. 211, 241, 2002.
A. V. Mordvinov and R.C. Willson, Effect of Large-Scale Magnetic Fields
on Total Solar Irradiance, Solar Phys. V. 215, 5, 2003.
A. V. Mordvinov and L. A. Plyusnina, Coherent Structures in the
Dynamics of the Large-Scale Solar Magnetic Field, Astron. Reports, V.
45, 652, 2001.
A. V. Mordvinov and L. L. Kitchatinov, Active Longitudes and
North-South Asymmetry of the Activity the Sun as Manifestations of Its
Relic Magnetic Field, Astron. Reports, V. 48, 254, 2004.
Thank you very much and hope for your successful future work!
Institute of Solar-Terrestrial Physics
PO Box 4026
126 Lermontov str., Irkutsk,
Dear Drs Hoeksema and Kosovichev,
On the request of Dr Kosovichev I am sending you a file
of my recent paper on the kinetic models of the solar wind
with magnetic field. This (very short because of the page limit)
paper is submitted for publication in the Proc. of the IAU
Symp. 233. In this work, I used data from the Wilcox
Solar Observatory. If you are interested in kinetic solar
wind models I'll be very glad to collaborate.
With very best wishes,
Tomsk State University, FTF
Lenin Ave., 36
Response to the request for opinions about continuing the collection of synoptic
magnetic field data by the Wilcox Observatory:
I would strongly recommend continuing the synoptic magnetic field measurements
by the Wilcox Solar Observatory. I would also recommend that an additional program
be initiated for which those data of 1 arcmin (44 Mm) resolution may be exceptionally
Consider the following possibility. Put a latitude and longitude grid over a computer
model of the sun such that the grid partitions the surface of the sun into equal area
boxes. Let each segment of the grid (e.g. a latitude segment between adjacent meridians,
or a meridian segment between adjacent parallels of latitude) be considered an
electrically conducting line element. Assume that all surface electric currents occur only
on line segments of the grid and nowhere else. The problem is to use the magnetograph
data to solve for the electric currents of the solar surface grid. This is an inverse problem
that can be tried for different grid resolutions. The goal is to plot and predict the growth
of mid-scale active regions. Line-of_sight magnetic data should be re-scaled to eliminate
the fictitious magnetic monopole contribution from the data
before the inverse calculation to solve for the currents is attempted. This is a simple
procedure. Also each node of the surface grid should have as much current leaving as
The usefulness of the grid-current calculation should be as follows:
It should allow early correlation of harmonic components of the solar magnetic field with
specific surface locations of active regions (photospheric electric currents).
Whereas the complexity of the photospheric field and its gradients might delay detection
of a new active region pattern until it is highly developed, the grid-current model
provides another visual pattern to supplement that of the photospheric magnetic field.
Specifically, it should distinguish between latitudinal currents (that create the dipole
component of the quiet years) with the longitudinal currents (that signal
large active regions).
It should provide information as to whether active regions correlate temporally over
distant regions of the sun, and if so, exactly how.
There is much that can be done with synoptic data of the quality obtained by the Wilcox
Solar Observatory. It should be used aggressively for prediction not only of the near-
earth domain but also for the detection and prediction of large-scale solar magnetic
Martin D. Altschuler
June, 7, 2006
Dr. Todd Hoeksema
Hansen Experimental Physics Laboratory
As you probably know, I am currently the P.I. of the COSPIN Consortium experiment
on Ulysses, which provides measurements of cosmic rays and other high energy charged
particles in the inner heliosphere between the orbits of Earth and Jupiter and up to
heliographic latitudes of 80° in both the northern and southern hemispheres. I constantly
use the global magnetic field measurements from the WSO to provide context for Ulysses
and IMP-8 measurements of the modulation and spatial gradients of cosmic rays as they
vary through the solar cycle. In probably the majority of the papers I have published on
these subjects in recent years, at least one figure has included a plot of the solar polar
magnetic fields and/or the tilt of the current sheet as computed by the WSO. I attach a
list of recent papers and talks in which I have made use of data provided on the WSO
While I clearly recognize and celebrate the marvelous new capabilities for high
resolution solar magnetic field studies, there remains the old problem of the forest and the
trees. With ever increasing resolution, the tendency is to focus on the detail, the trees and
even perhaps the branches and leaves, while for cosmic ray studies, and I would venture
for heliospheric studies in general, it is the global structure of the Sun's magnetic field,
the forest, that is most significant. WSO has been doing a first-rate job for many years in
providing a global overview of solar magnetic structure, and I have come to depend on it
for this information. I strongly endorse continuing support of WSO to provide these
measurements. The value of a long-running, continuous, and consistently produced data
set for studies of heliospheric variations on multi-decadal time scales cannot be
With best regards,
R. Bruce McKibben
Dept. of Physics and SSC/EOS
University of New HampshireR.B. McKibben
Recent Papers and Talks Based on Ulysses Cosmic Ray Measurements
That Incorporate WSO Observations
Ulysses COSPIN high energy telescope observations of cosmic ray and solar energetic particle
intensities since its distant Jupiter flyby in 2004
R.B. McKibben, J.J. Connell, and C. Lopate
Geophys. Res. Abs., 8, Abst. EGU06-A-05301, 2006.
Cosmic-ray diffusion in the inner heliosphere,
Adv. Sp. Research, 35, 518-531, 2005.
The modulated intensities of cosmic rays during Ulysses' return to the ecliptic: Ulysses HET and
IMP-8 CRNC observations
R.B. McKibben, C. Lopate, and M. Zhang
Geophys. Res. Abst., 6, Abstract EGU04-A-05176, 2004.
Ulysses COSPIN Observations of Cosmic Rays and Solar Energetic Particles from the
South Pole to the North Pole of the Sun during Solar Maximum
R.B. McKibben, J.J. Connell, C. Lopate, M. Zhang, J.D. Anglin, A. Balogh, S. Dalla,
T.R. Sanderson, R.G. Marsden, M.Y. Hofer, H. Kunow, A. Posner, and B. Heber
Ann. Geophys., 21, 1217-1228, 2003
Cosmic Ray and Solar Energetic Particle Observations in the 3-D Heliosphere near Solar
R.B. McKibben, J.J. Connell, and R.B. McKibben
Geophys. Res. Abs., 4, Abst. EGS02-A-01043, 2002
Modulation Near Solar Maximum and High Solar Latitudes: Observations from the Ulysses
COSPIN High Energy Telescope
R.B. McKibben, C. Lopate, and M. Zhang
Sp. Sci. Rev., 97, 367-371, 2001
Cosmic Rays at All Latitudes in the Inner Heliosphere
in “The Heliosphere Near Solar Minimum: The Ulysses Perspectives, (R.G. Marsden, A. Balogh,
and E.J. Smith, editors), Wiley-Praxis, pp. 327-371, 2001
These maps are extremely useful to our solar wind studies. They enable us to relate solar
wind speed studies to coronal holes and active regions. See Neugebauer et al. for many
references. JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 103, NO. A7, PAGES
Sorry, I know this is important, but I have run out of time. The WSO maps are a
fundamental building block for understanding the fields on the sun. It would be criminal
to shut it down, in my opinion.
Room 37-687, MIT, 77 Mass. Ave., Cambridge, MA 02139
Phone: 617-253-4284; fax: 617-253-0861; Email: firstname.lastname@example.org
08 June, 2006
Research & Scientific Support Dept. of ESA
Solar System Missions Division
Dr. J. T. Hoeksema
H.E.P.L. Annex B213
Stanford CA 94305-4085
Dear Dr. Hoeksema,
I am writing in my capacity as Ulysses Mission Manager in response to the item that
appeared recently in AGU’s SPA Newsletter concerning the future of the Wilcox Solar
Observatory synoptic program.
As you are aware, WSO data products are widely used by the Ulysses community, in
particular the source surface synoptic charts and heliospheric current sheet (HCS) tilt
data. These data will be especially important as a reference now that Ulysses is starting
its third set of polar passes. For example, one of the key scientific objectives of the
mission during 2007/2008 will be to look for N-S asymmetries of the kind found during
the so-called "fast latitude scan" in 1994/95. At that time, the Ulysses cosmic ray
observations showed that the HCS was offset by ~10º to the south. The synoptic data
from WSO, together with in-situ magnetic field observations from the Ulysses and Wind
spacecraft, were crucial in confirming this effect. A similar comparison in 2007 will
reveal whether or not this offset is once again present.
Another obvious area where WSO data will make an important contribution to the
interpretation of Ulysses measurements in 2007/2008 is the study of cosmic ray
latitudinal gradients. In contrast to the situation at the previous solar minimum in
1994/95, and as a result of the polarity reversal of the Sun’s magnetic field in 2000/2001,
Ulysses is expected to find negative latitudinal gradients for positively charged particles.
In all such studies, the HCS tilt angle is a much-used input parameter in modeling the
transport of galactic and anomalous cosmic rays in the heliospheric magnetic fields.
Indeed, the availability of a self-consistent synoptic data set covering multiple solar
cycles is of great value in the study of cosmic ray modulation, and will continue to be
important in the future.
I have forwarded your request for input to the Ulysses co-investigators, and am confident
that they will provide even more examples of the usefulness of the WSO synoptic
observations in the interpretation of their data. In summary, then, I fully support the
continuation of the WSO synoptic program and consider it to play an important role in
providing context data for the Ulysses mission.
Richard G. Marsden
Ulysses Mission Manager, ESA \
I was shocked to learn that regular observations of the solar magnetic
field at WSO might be stopped. It sounds as if someone would suggest
stopping Wolf number determinations and measurements of the solar
integral radio flux. For many years, I have been using your data both
in my research work and in daily forecasts. The corresponding
references are given in my publications. A few other research teams at
our Institute are conducting similar work.
As Vice-Chairman of the Russian Scientific Council on Solar-Terrestrial
Physics, I can contend that the WSO data are also widely used at the
Institute of space research and Institute of Applied Geophysics
(Moscow), Institute of Solar-Terrestrial Physics (Irkutsk),
Astronomical Observatories and Institutes at Ussuriisk, Yakutsk,
Odessa, Kiev, Tashkent, and Alma-Ata. Moreover I know that your data
are used many groups in USA, France, Germany, Japan and China. I
suppose that this problem is a topic for discussion in International
Counsel of Scientific Unions, especially IAU and SCOSTEP. So I am
sending the copy of the message to S.T. Wu and Dave Webb.
The appearance of new, higher-resolution observations cannot be an
excuse for ceasing the classical WSO observations. Firstly, their task
is quite different (analysis of the inner structure of the particular
active features) and secondly, reducing data from different
observatories to a single format would present a significant
I very much hope that the decision of closing these observations will
not be taken.
synoptic WSO data have an advantage that the
new, higher resolution data do not, namely, continuity over
three solar cycles. Four cycles would be especially
desirable, and more for future generations.
My collaborators and I have used these, especially the
different synoptic map sets for a number of purposes. The
main one has been principal components analysis and
independent components analysis. These involve finding
recurrent modes in the magnetic field distributions and the
ways they come and go with the solar cycle. The relatively
low resolution form of the WSO data actually is a plus in
I strongly urge that the WSO program be continued.
John K Lawrence
3380 Country Club Dr
Glendale, CA 91208
Physics & Astronomy, CSUN,
Northridge, CA 91330-8268
To whom it may concern
We are carrying out wavelet analysis and neural network modeling of solar magnetic
field time series. For that it is totally crucial to have continuous data of highest accuracy.
WSO at Stanford has produced such data since May 1975.
We are therefore very much appreciating the availability of that data. We have published
several articles using that data and have several new articles in progress.
We have taught neural networks to predict solar wind velocity from the photospheric and
computed coronal magnetic field, observed at WSO (Wintoft and Lundstedt, 1999).
With the availability of high resolution magnetic field data from MDI onboard we have
compared that data with WSO data. Since WSO has produced data over three solar cycles
we may even make predictions using MDI data that has only been available during one
cycle. In Boberg et al., (2002) we were capable to find in mean field data, observed with
WSO, the very important 1.3 year periodicity at tachocline (Howe et al., 2001). Since
WSO has produced data for over three cycles we could study that periodicity over three
Most recent we have studied synoptic solar magnetic fields, both using WSO and MDI
data. The first results of wavelet studies have been presented by Lundstedt at (AGU,
2005, SCOSTEP, 2006 and EGU 2006). The goal is to develop a neural network dynamo
model. This model is expected not only to improve our understanding of solar magnetic
activity but also to offer predictions of next solar cycle (24). We have already used WSO
polar magnetic field data to predict next solar cycle.
Again, without continuous WSO data these results should not have possible to obtain.
However, WSO has not only produced data over several cycles but also very accurate
data. Actually the best in the world. We therefore really hope that there will be
possibilities to continue the observations.
Dr. Henrik Lundstedt
Head of the Solar and Space weather group in Lund
Deputy Director, ISES
Swedish Institute of Space Physics
Scheelev. 17, SE-223 70 Lund, Sweden
Boberg, F., Lundstedt, H., Hoeksema, J.T., Scherrer, P.H., and W. Lui, Solar mean
magnetic field variability: A wavelet approach to WSO and SOHO/MDI observations, J.
Geophys. Res., 107, 15-1--17-7, 2002.
Howe, R., Christensen-Dalsgaard, J., Hill. F., Komm, R.W., Larsen, R.M., Schou, J.,
Thompson,M.J., and Tomre, J., in Helio- and Ateroseismology at the Dawn of the
Millennium: Proc. SOHO 10/GONG 2000 Workshop, ed A. Wilson, ESA SP-464 (ESA
Publication Division, Noordwijk, The Netherlands), 19, 2001.
Wintoft, P. and H. Lundstedt, A Neural Network Study of the Mapping from Solar
Magnetic Fields to the Daily Average Solar Wind Velocity, J. Geophys. Res., Vol. 104,
No A4, 6729-6736, April, 1999.
Lundstedt, H., Multiresolution Analysis of Solar Synoptic Magnetic Fields, presented at
AGU meeting, San Francisco, California, USA, 5 December 2005.
Lundstedt, H., Wavelet reconstruction of solar magnetic activity, presented at 11th
Quadrennial Solar Terrestrial Physics Symposium Sun, Space Physics and Climate, Rio
de Janerio, Brazil 6-10 March 2006.
Lundstedt, H., Reconstruction of solar magnetic activity using wavelets, presented at
EGU General Assembly meeting, Vienna 2-7 April 2006.
WSO is internationally famous for its magnetic field measurements. They
are literally used worldwide. No other instrument in the world performs this
type of measurement and provides analysis methods for producing three-
dimensional models of the magnetic field from the photosphere into the high
corona. I just finished refereeing an excellent paper submitted to Solar
Physics comparing Fe XIV emission in the corona with magnetic field
measurements from WSO. Exciting new work is taking place inferring how
and under what conditions the magnetic field in the corona controls the
properties of the corona. Only the WSO measurements could have provided
this opportunity. To discontinue these observations now would be a great
blow to our ability to understand the physics of the sun and make use of such
understanding to predict the increasingly-important effects of the sun on the
DR. RICHARD C. ALTROCK, DR-IV (GS-15), Principal Astrophysicist
Air Force Research Laboratory, Space Weather Center of Excellence
AFRL/VSBXS, National Solar Observatory at Sacramento Peak
3004 Solar Physics Dr., P. O. Box 62, Sunspot, NM 88349-0062
(505)434-7016; DSN 572-7542, ext. 7016; fax (505)434-7029 or 7079
Air Force email: Richard.Altrock@hanscom.af.mil
Internet email: email@example.com June 16, 2006
I would like to express my strong support in favor of the observations
of photospheric magnetic field performed by Wilcox Solar Observatory
since 1976. I should stress that the WSO data are the longest sets of
high quality data which permit to perform the study of the topology and
dynamics of the magnetic field and the origin of variability of the Sun
through cycles of activity. The use of the WSO data permits to get lots
of the important results.
To prove my statement I include the drafts of two new papers 100% based
on the WSO data related to the study of the latitudinal, longitudinal
structures and rotation rate of the photospheric field and their
variability during last 30 years and to the study of the relationship
between the basic topology of the photospheric magnetic field with the
heliospheric characteristics such as interplanetary field, solar wind
and geomagnetic perturbations.
Additionally I got very important results related to the longitudinal
structure reconstructed in the system rotating with such a velocity
which corresponds to the real rotational rate (found without any a
priory assumptions) of the level where the longitudinal structure is
originated from. This important result I plan to publish in the nearest
time, and to present in IAU Assembly in August 2006. These studies were
possible only due to the opportunity to use long data sets of such good
quality as the WSO observations.
Please find enclosed the titles of my recent presentations (7
contributions) in the IAU 233 Meeting in Cairo, in March 2006, and in
SOHO 17 Congress in Sicily, in May, 2006, 5 contributions submitted to
the IAU General Assembly, in Prague, 2006, two recent publications and
drafts of two new papers prepared for publication.
One more extremely important point is an open character of the data
usage policy of the WSO team, very friendly and intelligent way to
access the data which permits to proceed quickly to the analysis and
helps to reveal scientifically significant results.
I am sure that solar community should be deeply grateful to the WSO
team, and particularly to Prof. Ph.Scherrer and T. Hoeksema for their
great contribution to the one of the most important goals of the
research in solar physics related to the study of the origin of solar
dynamics and activity.
It should be clearly realized that these observations of the
photospheric magnetic field have great importance for the
understanding of the dynamics of the Sun, heliospheric structure and
geomagnetic perturbations which play a key role for the predictions of
the space weather.
Which best wishes,
Dr. Elena Gavryuseva,
Arcetri Astrophysical Observatory,
Largo Enrico Fermi, 5,
Tel. 39 055 2752 225
FAX: 39 055 2752 292