GONG Newsletter #31, August - National Solar Observatory

Newsletter
Number 31 July 2001
GONG+ is Online!
Last October, GONG celebrated its fth birthday, and
turning ve brought with it celebration and reections
on past accomplishments, but it also presented
an opportunity to look ahead to new goals and new
directions for the future – foremost, completing the
camera upgrade that we are calling GONG+, and
Deployment Readiness Review, at the end of February,
with GONG alumni Jim Kennedy, Rob Hubbard,
Lonnie Cole, and Bret Goodrich, along with
SOLIS’s Jeremy Wagner, helped us review the situation
and commit to the transition to GONG+
and bringing down GONG Classic. Since then it’s
The rst Big Bear GONG+ data for 7 hours showing excellent sensitivity out to l ≈ 1000.
next on the horizon, implementing GONG++, the
high-performance computing capability needed to
process the high resolution GONG data. Readying
the new camera systems for deployment has kept
everyone extremely busy. We have continued to operate
and maintain the GONG Classic network, support
the GONG+ deployment effort, and prepare for the
transition to GONG+ network operations and data
processing.
The path to deployment has been challenging, but
all of the milestones were eventually passed. The
been an exciting time for the GONG team around
the world. We completed deployments at Big Bear
(March 23), CTIO (April 20), and Learmonth (May
11), and at that time, with three sites in operation,
we ofcially transitioned to GONG+. The deployment
nished up with installations at Udaipur (June
21), Mauna Loa (June 22), and El Teide (July 27).
The deployments have incorporated the transplant of
the GONG+ camera system and preventative maintenance
work, which has been delayed to coincide with
the deployments and is long overdue.

Hats off to our deployment
teams – they have done a lot
of traveling in the last ve
months and have done a great
job.
The Project has had some
comings and goings in the
GONG team here in Tucson.
Susan Davidson, who was
with GONG for over six
years, and NOAO for nearly
25 years, retired at the beginning
of February. She will be
missed throughout the GONG GONG+ Instrument Team members (from left to right):
community, and we wish her Jean Goodrich, Roberta Toussaint, Roy Tucker,
the very best in the future. Sang Nguyen, Guillermo Montijo, Lana Britanik,
Bert Villegas, Ron Kroll, and Jack Harvey
Roberta Toussaint, who has
been with GONG for nearly a decade, has moved
over to NSO’s SOLIS Project. We look forward to
her continued association with GONG, which has
included her participation in the GONG+ deployment.
We also saw Tatia Wing move on and wish her
the best in her new adventures. David Landy will
be leaving at the end of the summer and setting new
goals as a graduate student at Indiana University.
in the production and deployment
of GONG Classic, and
it is great to have him back
on the team. Katrina Gressett,
Simon Kras and Kerri Donaldson
Hanna joined the DMAC
group, and Jeffrey Sudol will
be working with the Instrument
Team.
Kiran Jain, from the Udaipur
Solar Observatory, visited
Tucson in February and March
of this year, and was one of the
rst GONG+ users, producing
ring diagrams in both velocity
and intensity.
On the positive side of the ledger, Caroline Barban
joined the Analysis Group and is working on improving
the mode parameter estimates by simultaneously
tting the spectrum obtained in velocity and intensity.
Guillermo Montijo was welcomed back into the
fold. As many of you remember, he was a key player
A cut through 3-dimensional power spectra at 3.5 mHz for the
velocity (left panel) and intensity (right panel). The spectra
were generated by tracking a 20° by 20° region for 2 days as it
crossed disk center. Each gure extends ± 2.2 Mm -1 k x
and k y
.
GONG-SOHO 2002
Big Bear Solar Observatory - October 2002
Final dates and meeting information to follow via email, snail mail, and the
GONG www server.
The GONG bibliography is being integrated into the Astrophysics Data System at
http://adsabs.harvard.edu/Groups/search/Helioseismology or on the main ADS search
form. Keep your pre/reprints coming.

What Data Can I Get from GONG
GONG provides data freely to its members. Becoming
a member is simple — go to the GONG web page
and select the “Scientic Enterprise” link and then the
“GONG Membership Application” link and then the
“GONG Research Program Application” link. You can ll
out the forms electronically, or by using a text le. After
the forms are submitted and processed, you will be able to
search and order our data.
Some of the currently available products for the helioseismologist
are:
Power spectra of solar oscillations covering the range of
0 ≤ l ≤ 200, -l ≤ m ≤ +l, and 0 ≤ ν ≤ 8.33 mHz.
Time series of complex spherical harmonic coefcients as
a function of l and m in the range 0 ≤ l ≤ 200 and 0 ≤ |m|
≤ l.
Estimated frequencies, amplitudes, and linewidths of solar
oscillation modes, as a function of l, m, and ν covering
the range 0 ≤ l ≤ 150, -l ≤ m ≤ +l, and 1.2 ≤ ν ≤ 4.0
mHz.
Both the time series and power spectra are available for temporal
intervals of GONG months (GM), with 1 GM ≡ 36
days. Note, however, that the mode parameters are computed
from overlapping three-GM (108 day) temporal
intervals, with a one-GM spacing. Time series and power
spectra are also available for 0 ≤ l ≤ 45 for intervals of 1
GONG Year (10 GM or 360 days) and 35 GM. All data
from 7 May 1995 to 6 October 2000 have been processed
to time series and power spectra, and the mode parameters
have been computed on all possible 53 intervals of 3 GM.
For the non-helioseismologist, we have:
• Minute-by-minute images of the solar surface Doppler
velocity eld from 7 May 1995 to the present.
• Magnetograms every 20 minutes, plus derived synoptic
maps for Carrington rotation cycles 1896 through
1942; and
• Low-pass, temporally ltered, and geometrically registered
images of the surface Doppler velocity with a
cadence of 4 minutes and a lter width of 17 minutes,
useful for studies of slowly evolving ows from 7 May
1995 to 17 October 1998.
Finally, we have implemented a new data service that provides
near-real-time magnetograms with rough calibration
and a cadence of about one every two hours around the
clock. They can now be obtained at:
ftp://www.gong.noao.edu/pub/gong/magnetograms
Sasha Kosovichev called attention to changes in GONG+ observations of the X20 are of April 2, 2001 in NOAA 9393, and
Jack Harvey prepared this gure to show the temporal evolution. The left panel is the line-of-sight component of the magnetic
eld near the northeast limb averaged over 30 minutes prior to the are (2100-2129 UT). The next six panels show the difference
between the absolute value of the signal averaged over subsequent ten minute periods and the 30 minute pre-are average. White
(black) represents increasing (decreasing) line-of-sight signal strength. The panels are averaged from left to right over 2130-39
(preare), 2140-49 (rising phase), 2150-59 (maximum), 2200-09 and 2210-2219 (declining phase), and 2250-59 (post are). The
changes shown are a combination of seeing effects, change in perspective as the Sun rotates, line prole changes associated with
the maximum phase of the are, normal evolution of the active region eld, and real eld changes associated with the are. The
later panels are coincident with a strongly sheared sunspot. It is not clear if the are eld changes are in strength, direction or
position or some combination.

Site Focus ... Mauna Loa Solar Observatory
Mauna Loa Solar Observatory (MLSO) is operated by the High Altitude
Observatory (HAO), a division of the National Center for Atmospheric
Research and funded by the National Science Foundation. The observatory is
located at an elevation of 3,400 meters (11,000 feet) on the north slope of
Mauna Loa which is an active shield volcano rising 4,200 meters (13,800
feet) above sea level on the Island of Hawaii. The Mauna Loa site was
chosen for its unique properties that include a mountain thousands of kilometers
away from any continental land mass, young lava, and lack of
nearby vegetation. These factors keep local particulate contamination to a
minimum and provide the clean, dry air and dark skies necessary for exceptional
coronal measurements. MLSO operates an assortment of instruments
built by HAO and the NSO that observe the solar corona, chromosphere, photosphere,
and solar interior. HAO is dedicated to the study of the Sun and of the
response of the Earth’s upper atmosphere to the Sun’s output. As a nationally
sponsored laboratory, HAO is committed to the dissemination of its data to the
community at large.
Data collected include: solar oscillations by GONG and ECHO, used to determine solar interior rotation rates and structure; photometry
of the chromosphere and photosphere by PSPT (NSO) to study solar variability; chromospheric observations in Hα by PICS and Helium
1083 nm by CHIP; MK4 electron density images of the corona. PICS, CHIP and MK4 are used to study solar activity including coronal
mass ejections and long-term solar cycle variability. Movies and images of present and past data are available via the internet at:
http://mlso.hao.ucar.edu.
MLSO and GONG are guests on the National Oceanic and Atmospheric Administration’s (NOAA) Mauna Loa Observatory (MLO) site.
(http://stratus.mlo.hawaii.gov.) MLO is a baseline station for NOAA’s Climate Monitoring and Diagnostics Laboratory (CMDL). CMDL
conducts research related to atmospheric constituents such as gases, aerosols, solar radiation, meteorology, and precipitation chemistry that
are capable of forcing change in the climate of the Earth’s environment. MLO also hosts cooperative programs with the Network for the
Detection of Stratospheric Change and many other research institutions.
GONG’s web site http://www.gong.noao.edu is up-to-date with
Project status, scientific investigations and publications, access to
data products, and links to other activities within the field of helioseismology.
The FTP archives for GONG can be found at the anonymous FTP
address: ftp://www.gong.noao.edu/pub/gong.
The GONG Newsletter is also available on GONG’s web site as a
WWW document and an easily printable PDF document. We encourage
you to avail yourself of this service.
You can be removed from the hardcopy mailing list, and added to
the e-mail notification list, by simply sending an e-mail message to
gong@noao.edu.
The GONG Project is funded by the National Science Foundation (NSF) through the National Solar Observatory (NSO),
which is operated under a cooperative agreement between the Association of Universities for Research in Astronomy (AURA), Inc. and NSF.
The GLOBAL OSCILLATION NETWORK GROUP
P.O. Box 26732
Tucson, Arizona 85726-6732
USA