SHINE 1997

Research to Operations Workshop

The Space Weather Research to Operations Workshop was jointly organized by NOAA SEC, NSF, and Phillips Laboratory Geophysics Directorate.

Topics discussed were:

• agency activities and expectations
• assessment of needs
• model transition to operations
• identifying areas where research can support user needs

Issues addressed in the Research to Operations Roadmap:

• What products are now in the pipeline?
• How will these be transitioned?
• What current needs are not being pursued?
• What models and/or data sources should be developed?
• What display/visualization tools need to be developed for data and model results?

Views of Customer’s Needs

Intended to identify the specific needs of the various users of space weather services.

This included: 1) forecasters who are the interface between those who provide models and data and those who use their forecasts; 2) third party vendors who add value to the products provided by space weather services; and 3) end users who make decisions based on the space weather information provided.

Model Transition to Operations

This session will address current efforts to transition research models to operational products, and provide the opportunity to discuss what is needed for future transition activities from the perspective of both the modelers and the end users.

Identifying Areas Where Research Supports Users

Reviewers will be asked to identify the research products that are available: (1) now, (2) near-term, and (3) far-term. The discussion was then directed toward identifying the areas where research can best support user needs. Questions posed to the panel members:

• What current needs can be met by available or near-term data and models?
• What level of accuracy and validation is required?
• What level of support and what data are needed by researchers to make their models available?
• What is the most efficient way to transition research advances to operations?
• What applications are best addressed by physics based vs. empirical models?

SHINE Splinter Workshop

Topics discussed:

• importance of Research to Operations Workshop to SHINE interests
• follow-through on workshop issues
• recommendations to NSF concerning SHINE in conjunction with Space Weather Implementation Plan
• recurrent magnetic storm forecasting
• transient magnetic storm forecasting
• filament eruptions in storm prediction
• magnetic cloud modeling and storm prediction
• using white light coronagraph data to predict storms

Report on the 1997 SHINE Workshop

The grass-roots SHINE group, concerned with sources of space weather in the Solar, Heliospheric and INterplanetary Environment, met on January 17-18 at the NOAA Space Environment Center (SEC) in Boulder, in conjunction with the Space Weather Workshop. The group compiled a list of research and modeling areas that need immediate support for advancing space weather predictions from the Sun to Earth (L1), and will forward the list to NSF to serve as a guideline for proposal selections.

The working group on recurrent storms reviewed Joe Kunches’ recipe for storm forecasting at SEC and discussed questions raised by Joe as well as comments received from SHINE members in response to e-mail circulation of the recipe. Most comments recommended focused efforts to transition models from researchers to forecasters. SHINE members agreed, as discussed at length at the Workshop itself, that the transition phase is a bottleneck because no agency funds efforts that are applied rather than basic space science. Models nearing the transition stage were presented, and enthusiasm was expressed for trying them out in SEC’s meagerly funded but developing rapid prototyping (transitioning) center.

The working group on transient events heard presentations on recent research concerned with predicting magnetic field orientations in CMEs and magnetic clouds and predicting CMEs from X-ray and white light observations. Several members then led discussions on specific events, including the now famous Jan. 6-10 CME/magnetic cloud/storm identified by the ISTP community, and made plans for further collaborative research.

(N. Crooker)

Research Support Recommendations

Attendees of the SHINE splinter session of the Space Weather Workshop spent several hours identifying research needs in the area of solar/interplanetary studies which appear to be most crucial to the development of space weather applications.

The recommendations fall into four broad categories:

1) Research aimed at providing reliable warning of incipient solar disturbances that are likely to be geoeffective

The first element in the forecast chain is to obtain useful estimates of the timing, location, extent, speed, and other gross properties of Earth-directed (on-disk) CMEs near the Sun.

Examples of relevant physical phenomena include (but are not limited to):

• White-light coronagraph observations (“halo” and other events far from the plane of the sky)
• Formation of extended X-ray arcades
• Filament disruptions
• Long-duration X-ray events and associated spectral patterns
• Transient X-ray regional dimming
• Large (“X”) flares
• Transient EUV phenomena
• Type II (and possibly IV) radio bursts

Many of these and other indicators have a long history, and the literature is indeed replete with association studies of one kind or another. However, recent advances in the global understanding of large scale structures in the solar atmosphere, coupled with new observations from SOHO, Yohkoh, and other sources, lead us to believe that significant advances can now be made by evaluating anew the relationships of select signatures to various classes of events.

Any advance warning of oncoming solar disturbances issuing from successful application of near-Sun indicators will need to be fine-tuned by observations taken just upstream from Earth. Hence the second element in the forecast chain is improved utilization of L1 monitor data.

• Relevant research topics include (but are not limited to):
• Analyses of solar wind data; L1-Earth correlation studies
• Multi-spacecraft evaluation of effects of disturbance geometry
• Real-time algorithms for projected flow state at Earth
• Magnetic cloud detection and evaluation of prospective geomagnetic effectiveness
• Patterns in energetic particle fluxes, relation to interplanetary structures

To establish a useful space weather forecast capability, information gleaned from near-Sun sources as well as upstream monitors must be organized and integrated into a structured, well-conceived, semi-automated prediction scheme. Hence the final forecasting element is research which promotes development of optimized, “expert” systems for space weather applications.

These would include:

• Linear-filter and multi-variate correlation schemes
• “Fuzzy” expert systems
• Neural nets, genetic algorithms, etc.

2) Research dealing with longer-term forecast topics

SHINE attendees regard this research area as being on equal footing with the CME-signatures work, in terms of advancing the overall goals of the space weather initiative. (“Longer-term forecast” is here intended to mean those affording more advance warning than the typical 3-day transit time of CMEs.)

Examples of studies to be encouraged include:

• Patterns of coronal evolution (systematic structural changes, differential rotation profiles, “coronal trumpets”, etc.)
• Influence of emerging flux and evolving shear patterns on active region and streamer belt structures
• Filament structure and evolution
• Models of background (quasi-steady) coronal and solar wind flow structure

3) Research providing general support to space weather applications in general and to the above two efforts, in particular

Theoretical and empirical models of the large scale distribution of charged particle populations and their acceleration, relative to CME structure

Insights into the coronal acceleration mechanism, to be gleaned from SOHO observations out to 30Rs

Mapping of spiral magnetic field lines and distortions induced by travelling disturbances, using triangulation on type II and III radio emissions observed by interplanetary spacecraft

4) Support for new observations relevant to space weather applications

Continued advocacy for ongoing and new spacecraft missions and ground-based observations is key to resolving many of the challenges posed in space weather forecasting. While adroit analysis and numerical simulations with existing data sources will yield many advances in the next few years, large improvements in performance are most realistically anticipated from new observations.

SHINE recommends support for:

The ISTP program. This is essential for SHINE goals in the space weather initiative. Every effort should be made to encourage collaborative participation by SOHO and WIND researchers.

Developing programs for better in situ and imaging observations, such as the Solar Mass Ejection Imager (SMEI) and the Solar Terrestrial Observatory (STEREO) concepts.

Pre-launch analysis support for ground-breaking efforts like STEREO. Implementation of techniques for taking full advantage of unconventional observations is not trivial and must be worked out in advance to assure successful missions.

Developing a mechanism for taking advantage of unanticipated opportunities for spacecraft missions and ground-based observations relevant to space weather applications. Free rides for small packages can sometimes become available on short notice, and even partial support for experiments can be crucial.

Occasional ventures entailing more than the usual risks, such as active radar sounding of the corona. In such cases, where the costs are quite modest and the potential gains quite high, funding for well-considered proof-of-concept studies should be made available from time to time.

Reading List

A Reading List for the History of Numerical Weather Prediction in Meteorology

(Reference material courtesy of G. Siscoe)

A number of people at the SHINE meeting asked me about the history of numerical weather prediction in meteorology, which I keep referring to. Here is a short reading list on the subject.

Cressman, G. P., The origin and rise of numerical weather prediction, in Historical Essays on Meteorology 1919-1995, J. R. Fleming, ed., American Meteorological Society, 1996.

McPherson, R. D., The National Centers for Environmental Prediction: Operational climate, ocean, and weather prediction for the 21st century, Bull. Am. Met. Soc., 75, 363, 1994.

Nebeker, F., Calculating the Weather: Meteorology in the 20th Century, Academic Press, 1995.

Shuman, F. G., History of numerical weather prediction at the National Meteorological Center, Weather and Forecasting, 4, 286, 1989.

Nebeker is a great overview of the whole subject. Shuman and Cressman were directors of the NMC and advocate getting started as soon as possible. The McPherson article has the famous skill curve that shows slow steady improvement, emphasizing again the need to get started so that the process of improvement can begin.

Transient Events Study Group

Preliminary Analysis of the Solar Source of the Jan. 6-10 Event

1. Introduction

The LASCO partial-halo CME occurring late on Jan. 6 was used to forecast the arrival at Earth on Jan. 10 of the magnetic cloud which produced a geomagnetic storm. This association was made because the CME was halo-like, there were reports of activity near sun center on the Earthward-facing side, and the travel time to Earth was about right for a CME with a typical speed of 450 km/s. However, until now no one has tried to understand the nature of this activity and the likelihood of its connection to the CME. The importance of this event is that it is the first time that such a halo-type CME has been associated with a significant geomagnetic storm during solar minimum, and never have we had available such an impressive array of instruments with which to study it.

SHINE researchers seek to develop solar-interplanetary inputs to space weather studies. This event provides an ideal example of how SHINE can help improve understanding of the physics of geoeffective events through study of their sources at the Sun and the propagation of disturbances through the interplanetary medium to the Earth. This report is a preliminary step in such a study for the Jan. 6-10 event, which has already been well described at the Earthward end of the chain by the ISTP group.

2. Finding the Solar Source of the CME

Details of the CME are described in the LASCO press releaseand on the ISTP Web page. It was observed first in the C2 coronagraph on Jan. 6 at 17:34 and later in the C3 coronagraph before 19:50. Measurements of the expansion speed of the front on a height/time diagram yield 4 estimates of the onset time of the CME, two times for each coronagraph, at the solar limb and at disk center.

Onset at sun center Onset at limb

C2 14:02 15:48
C3 15:08 16:24

The expansion speeds are as projected in the plane of the sky and, therefore, are lower limits for the actual CME speed along the sun-Earth line.

We also note that the CME was observed as a partial arc over the SSW part of the sun moving in a southwesterly direction. A similarly positioned partial halo CME on Sept. 27, 1996 was associated with an erupting filament/active region and X-ray arcade south of sun center. Thus, we might expect a similar source location on the disk for this event.

3. Analysis of Solar Activity

However, at first glance the solar surface appeared relatively quiet on Jan. 6. The GOES whole-sun plotshowed little activity above the A1-level background, and Ha and Yohkoh X-ray images early and late in the day showed little change. The only enhanced regions were NOAA Reg. 8009, a small but bright emerging flux region with a few sunspots west of sun center, and Reg. SN84, a large, weak plage area with no sunspots near central meridian at S30. This region was bifurcated by a NW to SE trending polarity inversion line over which filament fragments had come and gone during the disk passage. This region is where the southern polar crown of filaments bends sharply to the north; there is evidence that such locations favor the production of mass ejections.

The Air Force observers at Ramey AFB in Puerto Rico, one of the stations in the AF SOON network acquiring daily optical image of the sun, provided a report of their observations on the 5th and 6th. At this time of year solar observations at Ramey extend from about 11:00 to 21:00 UT. During the overnight gap observers note whether significant activity, especially disappearing filaments (DSFs), may have occurred. Ramey reported no DSFs overnight on either Jan. 4-5 or Jan. 6-7. They also saw no DSFs on the disk on Jan. 5 during the observing day: 11:17-21:19 UT. However, a small filament did disappear in SN84 between Jan. 5 and 6 as confirmed by the SOON station at San Vito, Italy (see next table).

This filament was gone by the start of the observations at Ramey on the 6th at 11:13. Another filament centered at S24W01 disappeared between 13:01 and 14:53. This filament was not visible on an Ha image at 08:50 from Meudon Observatory in France, so that it may have formed on the 6th between 08:50 and the 11:13 start time at Ramey. Here is a summary of the Ramey report (at 18:00) on this DSF:

A 5-deg. long, normal density filament lying over the northern fringe of reg. SN84 “disappeared in a slightly eruptive fashion” [between the times above]. The filament had been very stable beforehand. It suddenly began dissipating with motion over a curving path. Some material began reappearing within 30 min., but then again dissipated along the reverse direction. Simultaneously with the DSF, an 8-deg. long filament lying over the southern part of the region suddenly displayed strong structural changes. This filament had also been very stable before. In addition, numerous small-scale plage flucuations occurred in the region center (between the filaments) during this period. Two small sunspots appeared at ~S35E05 during and after this period. The northern filament did not reform before the end of the observing day at 20:43.

DSFs ON JAN. 5-6, 1997

Station Disp. Time Location Length

Jan. 5: None reported

Ramey >5, 2119 <6, 1113 S17E05 5 deg.
San Vito >5, 1939 <6, 2300 S19E06
S20E10 (9 deg.)

Ramey 6, 1301 – 1453 S23W03 ~5 deg.
S24W01
S27W00

Jan. 7: None reported

A closer look at radio and X-ray data on Jan. 6 shows that there was at least weak coronal activity associated with this DSF. N. Gopalswamy reports that a “radio filament” consistent the location of the Ha filament, disappeared between 17 GHz imagesat 06:45 and 23:45 from the Japanese Nobeyama Radio Observatory. Gopalswamy and H. Hudson of ISAS in Japan also examined the Yohkoh SXT imagesduring Jan. 6. They found that a faint large loop over the filament position north of the bright active region loops had disappeared between images at 08:30 and 15:11. There were changes in other loops in this region, including the appearance of faint large loops to the south during the time of the estimated onset time of the CME. However, theer were no apparent motions in any of these structures. Finally, an extended plotof one of the GOES X-ray channels on Jan. 6 shows evidence of a weak long-duration event (LDE) from 14:30 – 16:30 UT. Such events have been associated with filament eruptions and CMEs, and the timing is consistent with the later phase of the DSF.

The GOES data do show that a distinct solar LDE occurred on Jan. 5 from 13:31 – 16:10 with a peak flux of A6. The Yohkoh SXT images indicate that this event came from the same south-central region as the above later DSFs; they show some brightening and changes in the S-shaped structure of the region. Initially, we thought that this event was the source of the CME on Jan. 6 and the cloud on the 10th. However, it occurred too early to match the extrapolated onset time of the CME, and also it is not consistent with the timing of the interplanetary disturbance (see below). In addition, we have not found any reports of DSFs on Jan. 5, although Ha images from Culgoora Solar Observatory in Australia show that a moderate-size dark filament just north of Region SN84 gradually dissipated during that day. Finally, C. St. Cyr confirms that there was no CME detected by LASCO on Jan. 5 that would be consistent with being associated with the LDE.

4. Interplanetary Propogation of Disturbance

Another consistency check on the solar source of the CME and cloud is provided by an assesssment of its transit speed between the source and the Earth in comparison to the solar wind speed observed at 1 AU. On Jan. 10 the WIND spacecraft was located between L1 and the magnetosphere. The front of the magnetic cloud was detected at WIND on Jan. 10 at 04:45 UT, the interplanetary shock arriving at 01:00. If the cloud traveled at a typical speed of 450 km/s from the sun to the Earth, its onset time at the sun would be Jan. 6 at 0900. This is consistent with the extrapolated onset times of the CME and the DSF near sun center after midday on Jan. 6, given the uncertainities of the measurements and of how the material was accelerated.

We can invert this procedure by assuming we know the source time and calculating the transit time to the shock (or cloud) at 1 AU. Assuming that the Jan. 5 LDE event is the solar source of the shock/cloud gives an average transit speed of 385 km/s. If the DSF is the source on Jan. 6, the transit speed is ~500 km/s (assuming a launch of the CME at 14:00, consistent with the C2 onset time.) Cliver, Feynman and Garrett (JGR, 95, 17103, 1990) found a generally linear relationship between the maximum in-situ solar wind speed of disturbances with confidently identified solar sources and the associated shock transit speed. On Jan. 10 the peak hourly-averaged wind speed in the WIND data following the shock was 465 km/s. Although the data points for both of the Jan. 5 and 6 candidate sources for the shock lie above the best-fit line in the Cliver et al. study, this analysis indicates that the Jan. 6 event is the preferred candidate source.

There were two other unusual aspects of the shock/cloud event. First, there were no enhanced fluxes of energetic protons or ions associated with it seen at WIND. This was confirmed by measurements from the Low Energy Telescope of the EPACT experiment, which measures particle fluxes above ~2 MeV/nuc with unprecendented sensitivity (D. Reames, priv. comm.). This lack of energetic particles is unusual for a fairly strong driver gas/shock event. Second, the Jan. 6-10 interval is the first time that a traveling type II kilometric radio burst has been detected by the WIND WAVES experiment. The burst can best be seen on the WAVES frequency vs time plot of Jan. 8as a persistent bright band of emission which peak intensity moves to lower frequencies with time. This pattern suggests an interplanetary shock was moving outward from the sun. In past data such kilometric bursts have usually been associated with energetic solar flares and strong shocks (e,g, Cane, JGR, 90, 191, 1985).

5. Conclusions

Our preliminary conclusion is that the cloud and storm at Earth on Jan. 10-11 were both associated with the CME near the sun on Jan. 6, which in turn had its source in a DSF and weak coronal activity just south of solar disk center around midday on Jan. 6. Newly formed sunspots were a signature of some emerging flux in this area. Although the solar activity was fairly weak, such weak correlations between classic solar observables and CMEs and interplanetary disturbances are not uncommon. Indeed this is a key reason why the forecasting of geoeffective disturbances is so difficult. A fundamental problem is our lack of near-sun observables of the ejected coronal material itself.

This report is preliminary. Corrections, new information or comments are solicited and should be sent D. Webb at the address below.

I would like to thank the following people who provided data and/or analysis efforts for this study: N. Gopalswamy of the Univ. of Maryland for Nobeyama and Yohkoh SXT data, H. Hudson of ISAS and L. Acton of Montana State Univ. for SXT analysis, E. Cliver of PL/GP for wind speed analysis, D. Reames of GSFC and S. Kahler of PL/GP for WIND type II and particle data, J. Steinberg of MIT for WIND plasma and IMF data, Sgt. D. Rose and S. Dahl of Ramey AFB for Ha data, C. St. Cyr of NRL for LASCO CME data, P. McIntosh of Heliosynoptics for Ha data, and S. Keil of PL/GP for Ha data.

Report produced 4 Feb 97 by David F. Webb (webb@plh.af.mil) of Boston College and Phillips Lab Geophysics Dir.