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                  UNDERSTANDING SOLAR TERRESTRIAL REPORTS
                     PART II - INTERPRETING THE REPORTS
                                REVISION 1.2



                                  _A_B_S_T_R_A_C_T

              Part I of this document discussed the morphology of
         solar and geophysical phenomena.  With this background now
         in hand, a discussion of the solar terrestrial reports
         themselves can begin.  The purpose of this document is to
         explain the meaning of the various sections of the Solar
         Terrestrial Forecast and Review which are posted over the
         networks on a weekly basis.  In addition, the purpose and
         application of the other reports, alerts and warnings will
         be discussed.  After having digested the material in parts
         I and II of this document, the interested reader should
         have enough background and knowledge to begin actively
         applying the information in the reports.  The reader is
         encouraged to digest part I of this document first (Part I
         - Morphological Analysis of Phenomena).  It may be
         obtained upon request from "[e-mail]".



   July 14, 1991







































                  UNDERSTANDING SOLAR TERRESTRIAL REPORTS
                     PART II - INTERPRETING THE REPORTS
                                REVISION 1.2



   _1.  _I_n_t_r_o_d_u_c_t_i_o_n

        The solar terrestrial reports posted over the networks  presently
   consist  of  several  reports, alerts and warnings.  The Solar Terres-
   trial Forecast and Review is the only regular weekly publication.   It
   contains  a  summary  of  conditions which occurred over the preceding
   week and includes forecasts for the next 10 to 20 days.   This  report
   is  the  one  which will be concentrated on most heavily in part II of
   this document.  It contains most of the  data,  forecasts  and  charts
   required and used in practical applications.

        The Major Solar Flare Warning is a brief message which is  posted
   over  the  nets when a major flare (or flares) may be possible.  These
   messages are only sent when regions on the solar surface  are  complex
   and   threatening   enough  to  produce  potentially  major  energetic
   activity.  They are therefore only intended to  alert  people  to  the
   increased potential for major flare activity.

        A Major Flare Alert is posted whenever a  major  energetic  flare
   erupts on the sun (of class M5.0 or greater).  Such an alert include a
   description of the event and any  outstanding  accompanying  phenomena
   (ex.  sweep frequency events, abnormally high radio bursts, etc.).  If
   the flare could have a terrestrial impact,  an  impact  assessment  is
   given within the body of the alert message.

        The Major Geomagnetic Storm Alert is posted whenever  geomagnetic
   conditions reach storm levels over middle latitudes.  These alerts are
   not posted when storm conditions may exist for high latitudes, because
   high  latitudes  experience a significantly greater number of magnetic
   storms than do the lower latitudes and fewer  numbers  of  people  are
   affected  by  the  high  latitude  storm  periods than middle latitude
   storms.

        We begin our discussion of the solar terrestrial reports with  an
   analysis  of  the solar terrestrial review section of the reports.  We
   will attempt to cover the language used and discuss the format of this
   section  of the reports.  Following this, we will continue with a dis-
   cussion of the Monthly Solar Terrestrial Review followed by a  discus-
   sion  of  the  Geomagnetic Storm Alerts.  The Major Solar Flare alerts
   and warnings should be more easily understood after this document  has
   been digested.

        The interested reader may need to re-read parts I and II of  this
   document  before aquiring a clearer understanding of these reports and
   their applications.  A great deal  of  material  is  covered  in  this



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                                   - 2 -


   document  and  may  not  be  fully  understood the first time through.
   Application of these reports to the various inter-related  fields  may
   require practice and persistence in order to understand the impacts of
   certain events on specific terrestrial systems (such as radio communi-
   cations).  The interested reader is encouraged to do personal research
   on the subjects of solar activity, ionospheric properties, radio  pro-
   pagation  and geophysical activity.  Research in these areas will sig-
   nificantly enhance ones understanding and  ability  to  interpret  and
   apply  the information contained in the publicized reports, alerts and
   warnings.



   _2.  _T_h_e _S_o_l_a_r _T_e_r_r_e_s_t_r_i_a_l _F_o_r_e_c_a_s_t _a_n_d _R_e_v_i_e_w

        This report is  the  primary  report  of  solar  and  geophysical
   activity.   It  includes  enough  information and data to be of use to
   many people involved in radio communications, solar physics  and  geo-
   physics.   It  is  issued once a week and contains summaries and fore-
   casts for the next 10 to 20 days.

        The report itself is compiled from raw data obtained from several
   sources.   One  of the major sources is the Space Environment Services
   Center (SESC), which serves as a major global  data-collection  center
   for space-related environmental data.  The SESC is responsible for the
   solar terrestrial information which is posted on  radio  stations  WWV
   and WWVH at 18 minutes past each hour.

        The data obtained from the various sources are all collected  and
   analyzed  by  before  being compiled into the reports which are publi-
   cally posted.  Computer models, coronal maps  and  recurrent  patterns
   are  all examined and analyzed.  The results are incorporated into the
   various forecasts in the reports.  The actual prediction  methods  are
   beyond the scope of this paper.

        In this section, we will begin a systematic analysis of the vari-
   ous  sections  of  the Solar Terrestrial Forecast and Review.  Some of
   the terms contained herein may not  be  clearly  defined.   For  those
   terms  which  are unclear, the interested reader is encouraged to con-
   sult the "Glossary of Solar Terrestrial Terms", available upon request
   from "[e-mail]".

   _2._1.  _S_u_m_m_a_r_y _o_f _S_o_l_a_r _T_e_r_r_e_s_t_r_i_a_l _A_c_t_i_v_i_t_y

        This section of the report summarizes the highlights of solar and
   geomagnetic activity which took place over the preceeding week.  Solar
   activity is given first, followed by  a  summary  of  geomagnetic  and
   auroral  activity.  Following this, a summary of the HF and VHF propa-
   gation conditions for the preceeding week are given.  Any particularly
   severe  solar  or terrestrial activity will be given special treatment
   in this section.

        Basically, the summary of solar activity includes a discussion of
   those  regions  on the sun which exhibited abnormal signs of activity.



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                                   - 3 -


   This may include a description of major solar flares, noteworthy fila-
   ment  disappearances,  or  unusually large coronal holes.  It may also
   include a description of various unusual or impressive forms of  limb-
   activity  such  as  prominences,  plage  or  faculae activity, or limb
   surges or flares.

        In all of  the  solar  summaries,  references  will  be  made  to
   specific  regions  postfixed  with specific numbers (ie. Region 6354).
   These "region numbers"  are  simply  sequential  numbers  assigned  to
   active  regions  as  they  appear or are identified.  The numbering of
   these regions was started by the  SESC  many  years  ago.   The  first
   region  to  be assigned was given a region number of 1.  Consecutively
   identified regions were given numbers of 2, 3, 4 and so on.  Each  new
   region is given the next consecutive region number.

        In order for a region to be assigned a  region  number,  it  must
   qualify  according to one of the following criteria: (1) If the region
   has a sunspot group which has a first-postion  type-classification  of
   C,  D,  E, F or H, it will be given a region number (see the "Glossary
   of Solar Terrestrial Terms for a description of the sunspot  classifi-
   cation  scheme).   (2)  If two or more reports confirm the presence of
   class A or B spots (again, see the above-referenced document), it will
   be  given  a region number.  (3) If the region produces a solar flare,
   it will be given a region number.  (4) If the region  is  "bright"  in
   H-alpha light and exceeds 5 heliographic degrees in either latitude or
   longitude, it will be given a region number.  These four criteria  are
   used  in  determining  what areas are assigned solar region numbers by
   the SESC and which areas are not.

        The vast majority of solar summaries include statements regarding
   the  intensity  (or  class)  of  specific  flare  events.   Flares are
   categorized using two types  of  classifications.   The  first  method
   categorizes  a  flare  with  regards  to  its  output  energy at X-ray
   wavelengths  measured  by  orbiting  satellites.   The  second  method
   categorizes  flares  according to their size and brightness at optical
   wavelengths (observed  using  monochromatic  H-alpha  light  filters).
   Both  of these flare classifications are described fully in the "Glos-
   sary of Solar Terrestrial Terms."  Refer to it for more information.

        The positions of all solar regions and events are given according
   to  the  format:  AxxByy, where xx represents a latitude (in degrees),
   "A" represents either the "N" (North) or "S" (South) solar hemisphere,
   "yy"  represents  the solar longitude given in degrees east or west of
   the central solar meridian, and "B" represents either  "E"  (East)  or
   "W" (West) of this central meridian (ex. N26E72).  The exact center of
   the visible sun represents the origin where the longitude is  measured
   from.   The extreme limbs of the solar disk represent longitudes of 90
   degrees (either East or West, depending on which limb  you  look  at),
   while  the  extreme  poles  of  the  sun represent 90 degrees latitude
   (either North  or  South,  again  depending  on  which  hemisphere  is
   observed).

        It should be noted  that  the  orbit  of  the  earth  carries  us
   slightly  above  and  below  the  suns rotational equator.  During six



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                                   - 4 -


   months of the year, we are above the northern  portion  of  the  solar
   equator,  while during the next six months, we fall below the southern
   portion of the solar equator.  Near the  equinoctial  periods  (spring
   and  fall), our orbit places us at our maximum distance above or below
   the solar equator.  If, at these times of the  year,  the  earth  were
   moved in a straight line toward the center of the sun, the earth would
   make contact with the suns surface at a latitude of about 7.3  degrees
   with  respect  to  the  solar  equator.  Although these periods do not
   exactly coincide with the each equinox (ie. maximum  southerly  extent
   is  achieved on 07 March, while maximum northerly extent is reached on
   09 September), they do coincide within a month of the equinox.

        These latitudinal changes are important, since it alters the  way
   we  must  observe  the sun.  During the equinox periods, the center of
   the sun as we see it is actually about 7 degrees to the north or south
   of the actual solar equator.  If this were not taken into account, the
   measured positions of sunspots and other  surface  features  would  be
   grossly in error.

        The important point to remember when studying  the  positions  of
   sunspot groups is that the coordinates given represent the position of
   the sunspots relative to the rotation axis of the sun as  viewed  from
   earth.   For  example, a sunspot group located at a position of N21E62
   represents a position 21 degrees north of the solar  equator,  and  62
   degrees  east  of  the solar central meridian (or 28 degrees away from
   the eastern limb [ 90 - 62 = 28 ]).

        Since the sun rotates from east to west, all sunspot  groups  and
   other  observed  features rotate in the same direction.  More specifi-
   cally, the sunspots rotate at an average speed of about 13 degrees per
   day.   So  the  sunspot  group  located  at N21E62 would be located at
   N21E49 the following day, and N21E36 the day  after  that.   They  may
   also occasionally drift in latitude, although the drift in latitude is
   negligable most of the time.

        Following the solar summary,  the  summary  for  geophysical  and
   auroral  activity  is  presented.   These  summaries  should be mostly
   self-explanatory with the exception of possible notes  regarding  mag-
   netic fluctuations.

        In summaries of particularly intense  magnetic  activity,  state-
   ments  may be made regarding the maximum intensity of some of the mag-
   netic fluctuations observed during the period being  reviewed.   These
   summaries  will  generally  involve  the terms _n_a_n_o_t_e_s_l_a and/or _g_a_m_m_a,
   which are synonymous.  The  intensity  of  magnetic  fluctuations  are
   latitude-dependent.    Higher   latitudes  naturally  experience  more
   intense magnetic fluctuations than  the  lower  latitudes.   Southerly
   middle   latitude   regions  consider  magnetic  fluctuations  of  500
   nanotesla (_n_T) to be very severe, while high  latitudes  may  consider
   fluctuations  of  2500  nT  to  be  very severe.  The magnetic A and K
   indices have been developed to aid in equating the intensity  of  mag-
   netic fluctuations over wide latitudes.  For example, a magnetic fluc-
   tuation at Anchorage Alaska  may  be  considered  to  be  as  "equally
   intense"  as a similar fluctuation in California if the A or K-indices



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   for both locations are equal, even though the actual magnitude of  the
   fluctuations at Anchorage are much higher than the corresponding fluc-
   tuations in California.  A K-index of 4  at  Yellowknife  in  northern
   Canada  may correspond to a magnetic fluctuation of 160 nT, while a K-
   index value of 4 at Boulder Colorado may correspond to an actual  mag-
   netic  fluctuation of only 50 nT.  Both fluctuations may be considered
   _e_q_u_a_l_l_y _s_e_v_e_r_e based on how often fluctuations of that  magnitude  are
   usually  encountered  for  that  latitude.   Yellowknife may encounter
   fluctuations of 50 nT  on  a  daily  basis  whereas  Boulder  may  not
   encounter  magnetic  fluctuations  of that magnitude for weeks.  Hence
   the need for indices which can equalize the latitudinal dependencies.

        Notes of auroral activity in the review section of the report are
   generally  limited  to  descriptions  as  described in the Glossary of
   Solar Terrestrial Terms.  However, for extraordinary  events  such  as
   occur  during  auroral  storms, a more detailed examination of auroral
   activity may be given.  Such descriptions may include  auroral  types,
   color  fluctuations, pulsations or movement patterns of auroral forms.
   All of these descriptions are  contained  in  the  Glossary  mentioned
   above and part I of this document.

        Notes regarding HF and VHF propagation are  usually  confined  to
   brief  accounts  of  overall  global conditions.  These conditions are
   generally rated as either above normal, normal, below normal  or  very
   poor.   Above  normal  propagation  indicates strong signals which are
   abnormally stable.  Above normal propagation is most often  associated
   with good to very good DX potentials.  Normal propagation denotes nor-
   mal conditions after considering the season and  the  position  within
   the sunspot cycle.  It is compared with the average conditions experi-
   enced over previous seasons and solar cycles.  Below  normal  propaga-
   tion  is usually associated with increased geomagnetic activity and is
   more consistent with signals of lower  quality,  less  stability,  and
   weaker  strengths.   Chances  for  DX drop noticably during periods of
   below normal propagation, except for the VHF bands where  an  increase
   in DX may actually occur.  Very poor propagation is most often associ-
   ated with magnetic storms or PCA events where signal absorption,  fad-
   ing  and instability dramatically affect the quality of signals.  Dur-
   ing intense storms, localized _b_l_a_c_k_o_u_t  conditions  may  occur.   This
   term  may be used in these instances to denote exceedingly high signal
   absorption levels.  Again, the exception  is  VHF  frequencies,  where
   long-distance  communications often improves during periods of high HF
   absorption or blackout periods.  However, the quality of the VHF  sig-
   nals may be quite poor despite the enhanced communication range.

   _2._2.  _S_h_o_r_t _T_e_r_m _S_o_l_a_r _T_e_r_r_e_s_t_r_i_a_l _F_o_r_e_c_a_s_t

        This section of the report follows the same  basic  structure  as
   the  review described in the last section, except that predictions are
   given instead of reviews.  The predictions are  made  using  the  same
   methods  described  in the preceding sections, but are translated from
   tables and charts into sentence form.

        This short-term prediction section is intended to point  out  the
   highlights which can be expected over the coming week.  Overall global



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   conditions are given in this section of the  report.   Therefore,  the
   person  interested  in radio communications or auroral activity should
   keep in mind the nature of this section.  It is not intended  to  list
   the  possible localized phenomena which might occur.  Just the general
   overall global conditions are stated.

        The short term forecasts should be used as a guide only.  The art
   of  predicting  geomagnetic  storms and major flares is by no means an
   easy  process.   There  are  many  variables  which  are  unknown  and
   processes  which  are not fully understood yet.  Although we have made
   great advancements in the fields of solar physics and  geophysics,  we
   have  a  long  way  to  go  in the area of predictions.  The forecasts
   presented in these reports may therefore be in error at  times.   They
   are,  however,  based  on  the most current models and the most recent
   data.

   _2._3.  _S_o_l_a_r _R_e_g_i_o_n _S_u_m_m_a_r_y

        The summary of solar regions is the section of the  report  which
   is  in  tabular  form  and includes the region numbers, sunspot sizes,
   sunspot classes, angular extents, magnetic configuration,  etc.   This
   section  is of great value to those who are tracking sunspot groups or
   watching for signs of growth or increased magnetic  complexity  and/or
   flaring.

        Although each of the aspects of this table are described  in  the
   Glossary  of Solar Terrestrial Terms, we will elaborate on some of the
   more vague terms of in this section.

        Each solar region is given a number and its position on the solar
   disk  is  measured  (as  was  described  above).   This identifies and
   defines the exact position of a solar region on the  sun.   The  posi-
   tional  description  (ie. the latitude/longitude description) is rela-
   tive to the hemisphere of the sun which is  in  view.   That  is,  the
   longitude  of  a solar region is relative to the center of rotation as
   seen from the earth.  This places the 00  degree  longitude  (ie.  the
   central  meridian)  continuously  at  the center of the sun (in a line
   stretching from the north solar pole through the center of the disk as
   observed  from  the earth, to the south solar pole).  All of the solar
   regions rotate while the longitudinal lines remain  stationary.   This
   method  of  marking  positions of sunspots and other phenomena is very
   adequate, but fails to describe the position of sunspots  on  a  solar
   global  basis  with  respect to a fixed 360 degree longitudinal system
   (as is employed for the Earth).

        In order to solve this problem, a system was developed  to  begin
   mapping  active  regions  on  a  fixed  solar geographical basis.  The
   actual longitudinal position of sunspots are therefore recorded in two
   different  ways.   The first way (described in the preceding sections)
   enables us to determine how far away a solar region is from  the  cen-
   tral  meridian.   It  effectively  separates the observable solar disk
   into an east and a west hemisphere with the dividing  line  coinciding
   with  the  central  solar meridian.  The second method is analagous to
   the way we have mapped  the  Earth,  with  fixed  lines  of  longitude



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   dividing up the entire sphere.

        The  figures  in  the  region  summary  under  the  heading  "_L_O"
   represent this second mapping method.  This second method is useful in
   determining the movement of a sunspot region compared to the  flow  of
   gases  around  the  sunspot  region.   Sometimes,  sunspots  will move
   slightly slower than the gases around the spot, which  will  gradually
   cause  the longitudinal location of the sunspot to change.  Sometimes,
   they move faster than the gases normally do at that location.   So  by
   observing  these longitudinal values, you can determine whether a sun-
   spot is moving faster or slower than usual.

        This method of referencing sunspots is also useful in identifying
   regions  of  the sun which are abnormally active.  During the years of
   maximum solar activity, the sun often  exhibits  longitudinal  regions
   which  are  more  active  than other longitudes.  During solar maximum
   years, there are often two areas of  abnormal  activity  separated  by
   about  180 degrees.  By observing the positions of sunspots using this
   method of mapping, the active  solar  longitudes  can  be  discovered.
   This is valuable for those who want to forecast solar activity.  Like-
   wise, some solar longitudes are often regions of enhanced  corpuscular
   emissions  (ie.  regions  where matter is ejected from the sun), which
   can  significantly  affect  radio   communications   and   geomagnetic
   activity.   Plotting the positions of these active longitudes can also
   be of tremendous aid in predicting  recurrent  storms  or  periods  of
   increased geophysical activity.

        The column in the table labelled "_Z" represents an optical  clas-
   sification  scheme  for  sunspots  and sunspot groups.  The details of
   this classification method are given in the Glossary of Solar  Terres-
   trial  Terms.  The interested reader is directed to consult this docu-
   ment for more information.  It categorizes the optical shape and  com-
   plexity of sunspot groups.

        The column labelled "_L_L" represents the  angular  extent  of  the
   sunspot  group.   Angular extent is given in solar degrees.  Comparing
   this value with the number of spots within the region (denoted by  the
   "_N_N"  column  of the table) yields the density of the group.  The den-
   sity is important because it is an indirect measure of  the  gradients
   of  magnetic  fields  within  the region.  High gradients produce more
   frequent and more severe solar flares, while weak gradients  are  usu-
   ally  associated  with  less-compact  spot  groups  which produce less
   severe and less frequent flares.

        The "_M_A_G _T_Y_P_E" or magnetic-type of sunspot groups as noted in the
   last  column  of  the table can also be used to determine the magnetic
   complexity and magnetic gradients within active regions.  Consult  the
   Glossary mentioned above for more information regarding these classif-
   ications.

        In addition to details on spot groups, this region of the  report
   also  enumerates  those  areas which are _n_o_t associated with sunspots,
   but contain areas of  enhanced  H-alpha  plages.   These  regions  are
   assigned  region  numbers  according  to the rules noted above.  These



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   regions are often the sites for sunspot formation.  They may  also  be
   associated with old regions which are decaying.

   _2._4.  _G_e_o_m_a_g_n_e_t_i_c _A_c_t_i_v_i_t_y _S_u_m_m_a_r_y

        Following the solar  region  summary,  a  graphical  analysis  of
   recent geomagnetic activity is presented.  This graphical table charts
   planetary geomagnetic activity as it is  recorded  for  many  magnetic
   observatories  around  the world. It includes recent data for the last
   96 hours up to the time the report was compiled.  The use of planetary
   geomagnetic  activity  gives a good indication of global activity from
   the high latitudes to the low latitudes.

        This chart has been constructed from each of the 3-hourly K-index
   values  reported  by  all of the participating magnetic observatories.
   Each graph line, therefore, represents a 3-hour period of  time.   The
   time  on  this  graph  is in Universal Time (relative from Greenwhich,
   England).  Therefore, the first graph line of  this  chart  represents
   the  activity  occurring  from 00 UT to 03 UT (actually, from 00 UT to
   02:59:59 UT).  The second line represents activity occurring  from  03
   UT to 06 UT, and so on.

        The left-hand side of the chart relates the levels of geomagnetic
   activity  to the approximate corresponding severity of activity.  This
   activity is defined from "Very Quiet"  levels,  which  corresponds  to
   magnetic  K-indices  of  zero,  to  "Extremely  Severe"  levels  which
   corresponds to magnetic K-indices of about nine.

        The right-hand side of this chart serves as a _v_e_r_y _r_o_u_g_h _g_u_i_d_e to
   the potential severity of magnetic-induction that _m_i_g_h_t be experienced
   during corresponding levels of magnetic activity.  By "magnetic induc-
   tion,"  we  mean  the  severity  of magnetic fluctuations necessary to
   begin influencing ground-based systems such  as  electrical  powerline
   systems, telecommunications systems, pipeline networks, etc.  This end
   of the chart is not intended to be a  definitive  classification,  but
   rather  is  only  meant  to serve as a _p_o_t_e_n_t_i_a_l indicator to possible
   magnetic-induction.  There are a great many  variables  that  must  be
   taken  into  account before magnetic fluctuations can be qualitatively
   classified as capable of inducing  electrical  currents  into  ground-
   based  systems.   These  variables  are  not considered in this chart.
   Only the general level of magnetic fluctuations are considered and are
   related  to possible magnetic induction.  Such localized parameters as
   air-earth conductivity, ionospheric current system parameters, electr-
   ical  field configuration, ground resistivity, and ground-based system
   network configurations must be considered (among other things)  before
   true  hazards  regarding magnetic induction can be determined.  There-
   fore, this area of the chart should be  used  only  as  a  very  rough
   guide.   Nothing  more and nothing less.  It should be noted, however,
   that magnetic fluctuations rated as K-indices greater than 6 generally
   become  capable  of  wide-spread  electrical current induction. Storms
   with  fluctuations  this  high  are  usually  capable  of  influencing
   ground-based systems over wide areas.

        The geomagnetic activity graphed in  this  chart  represents  the



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                                   - 9 -


   _p_e_a_k  global magnetic activity observed during the respective periods.
   It does _n_o_t represent average magnetic activity.  This is important to
   realize.   These  K-index  values  are not the same values reported on
   radio stations WWV and WWVH.  The values reported  by  these  stations
   represent the magnetic activity occurring at Boulder, Colorado.  Since
   this chart is derived from measurements of geomagnetic activity around
   the  world  (not  at  one specific location), the planetary values are
   more valuable and applicable on a global scale.

   _2._5.  _1_0-_D_a_y _G_e_o_m_a_g_n_e_t_i_c _A_c_t_i_v_i_t_y _F_o_r_e_c_a_s_t

        This chart graphs the expected levels  of  planetary  geomagnetic
   activity  over  a  10-day period.  Each day is separated into three 8-
   hour segments.  Each line of the chart therefore represents one  eight
   hour interval of time.  This chart graphs expected conditions relative
   to _U_n_i_v_e_r_s_a_l _T_i_m_e.  That is, the first line after each  date  dividing
   line  represents  expected conditions between 00 UT and 08 UT for that
   day.  The middle graph line represents conditions expected between  08
   UT  and  16  UT.   The  last  graph  line  for  each  day in the chart
   represents the magnetic activity that is expected from 16 UT to 24 UT.
   This chart should be more easily interpreted than the previous geomag-
   netic activity summary chart.  It is certainly more valuable.

        The predictions are based primarily  on  data  regarding  coronal
   holes,  potential  recurrent  activity,  diurnal  trends and potential
   solar activity influences.  The transient solar component  (ex.  major
   flares)  are not included as part of this prediction, since flaring is
   extremely unpredictable and forecasts of potential  major  flaring  in
   excess of a day or two is very unreliable.

   _2._6.  _G_r_a_p_h_i_c_a_l _A_n_a_l_y_s_i_s _o_f _S_o_l_a_r _A_c_t_i_v_i_t_y

        The graphical chart summarizing solar activity is  produced  each
   week for a 60-day period.  This period covers two complete solar rota-
   tions and is sufficient to show the cyclic behavior of solar  activity
   from one cycle to another.

        The solar flux (the intensity of solar radio  noise  observed  at
   10.7  cm  wavelengths)  is  plotted  in this graphical analysis.   The
   solar flux represents the slowly varying component  of  the  sun  (see
   part  I)  and  is strongly correlated with the number and intensity of
   sunspot groups on the solar surface.  The higher the  number  of  sun-
   spots  visible,  the  higher  the  solar  flux.  As sunspots disappear
   behind the western solar limb, the solar flux decreases.  The 10.7  cm
   solar radio flux is therefore a good indicator of the overall state of
   the observed solar environment.

        Under normal conditions, the plot lines for the  solar  flux  are
   plotted  using  asterisks  (*).   However,  on  days when major flares
   erupt, these plot lines are changed from  asterisks  to  "F"'s.   This
   enables readers to determine the period during the rotational cycle of
   the sun when major  flares  occurred.   In  most  cases,  it  will  be
   observed that most of the major flare activity occurs during the rota-
   tional peak of each cycle.  There are, however, exceptions to this, as



                               July 14, 1991





                                   - 10 -


   will occasionally be noted.

        Plot lines are only changed from  asterisks  to  F's  when  major
   flares erupt which meet or exceed an X-ray intensity of class M5.0.  A
   flare of class M4.9 may be a fairly major event, but is not considered
   a  major  class  flare  since it never reached M5.0 class intensities.
   Most flares, however, are either above or notably  below  this  limit.
   There  are  many  more  flares  of class M3.0 intensity than there are
   flares of class M4.0 intensity.  Most  major  flares,  therefore,  are
   observed  to  occur  above  this  M5.0 transition level.  Very few are
   borderline cases.

   _2._7.  _2_0-_D_a_y _S_o_l_a_r _A_c_t_i_v_i_t_y _F_o_r_e_c_a_s_t

        The 20-day solar activity forecast chart is constructed based  on
   the  activity  which  was  observed  over previous solar rotations, in
   addition to the status of the regions which are currently  visible  on
   the  sun.   The  intensity, size and number of sunspots in each region
   are all analyzed (among other things) before this prediction chart  is
   produced.

        The plot lines of this chart  represent  the  solar  flux  levels
   which  are  expected  to occur throughout the 20-day period covered by
   the chart.  The actual flux values will  frequently  differ  from  the
   actual  flux  values  observed, since predicting the activity of solar
   regions is still very difficult to do beyond approximately  one  week.
   Regions  behind  the  sun  may be developing which could significantly
   alter the shape of the prediction charts.   These  regions  cannot  be
   seen  or  detected  in any way until they approach the eastern limb of
   the sun.  Hence, these solar activity predictions should be used  only
   as  a  guide.   The  predictions are generally good at forecasting the
   times when the solar flux will peak or  reach  its  minimum  during  a
   rotational  cycle,  and  this  can  be  of  tremendous value to people
   interested in the level of ionospheric  ionization  which  is  propor-
   tional to the solar flux.

        Flares are not included in this  prediction  of  solar  activity.
   Flares  are  extremely  difficult  to predict, even in the short-term.
   Our knowledge of flares has grown rapidly since the early part of this
   century.   However,  our knowledge is still not sufficient to reliably
   predict the occurrence of major  flares  over  periods  in  excess  of
   several  days.  Therefore,  this  graphical solar activity forecast is
   limited to a treatment of the solar flux _o_n_l_y.  As far as  flares  go,
   an  increasing  solar  flux  generally  increases  the  risk for major
   flares.  The higher the solar flux values, the greater  the  risk  for
   major  flares,  since the solar flux is directly related to the number
   and intensity of active regions on the sun.

   _2._8.  _H_F _R_a_d_i_o _S_i_g_n_a_l _P_r_o_p_a_g_a_t_i_o_n _P_r_e_d_i_c_t_i_o_n_s

        This  section  of  the  Solar  Terrestrial  Forecast  and  Review
   involves  the  propagation  of  high-frequency  (HF)  radio waves over
   long-distances.  It is a forecast of the expected quality of HF  radio
   signals travelling over long-distances.



                               July 14, 1991





                                   - 11 -


        The quality of radio  signals  is  divided  into  several  areas.
   Radio  signals  which  have  outstanding  strength  and stability over
   long-distances are categorized as  _e_x_c_e_l_l_e_n_t.   These  conditions  are
   rarely  observed  and  occur  more frequently over the lower latitudes
   than the high latitudes.  Signals  which  are  abnormally  strong  and
   stable  over  long-distances  are  classified as _v_e_r_y _g_o_o_d.  These are
   above-normal conditions when considering the  time  of  year  and  the
   state  of  the  solar cycle.  Signals which are normal for the current
   season and state of the solar cycle are given a  _g_o_o_d  classification.
   These  signals  are generally stable and relatively strong considering
   the time of year, but may suffer  some  minor  fading  or  distortion.
   Noise  may  also  be somewhat of a factor, but is generally tolerable.
   When signals fall below the normal quality, they may be categorized as
   _p_o_o_r.   Poor radio signals over long distances are those which experi-
   ence moderate to strong fading or flutter, abnormally high  levels  of
   absorption,  or  increased  levels of noise (or any combination of the
   above).  Long-distance propagation is still usually possible in  these
   cases,  but  suffer significantly increased levels of distortion which
   may hamper attempts at long-distance voice contacts.  _V_e_r_y _p_o_o_r  radio
   signal  propagation  occurs  when signals experience severe fading and
   flutter, high levels of absorption, high levels of noise and high lev-
   els  of  distortion  (or any combination of the above).  Long-distance
   communication usually becomes very difficult during these periods  and
   may  not be possible at all over some regions.  When radio signals are
   unable to be propagated at all over long distances, or are  very  poor
   over  short  to  moderate  distances,  communication is rated as being
   _e_x_t_r_e_m_e_l_y _p_o_o_r.  This category will only  usually  be  encountered  at
   higher latitudes and during periods of intense geomagnetic storming.

        In these forecasts, each day is composed of three  8-hour  inter-
   vals.   These  forecasts  are  also correlated with _l_o_c_a_l _t_i_m_e, not UT
   time as are the geomagnetic forecasts.  The first plot  line  of  each
   day  represents  the  interval  between 00 (midnight) and 08 am, local
   time.  The second plot line represents the period between 08 am and 04
   pm (or 08:00 to 16:00) local time and so on.

        There is one _v_e_r_y _i_m_p_o_r_t_a_n_t note which should  be  understood  by
   all  those  who  use  these  forecasts  as  guides.  The local time of
   attempted communications is a very important factor  in  long-distance
   communications  due  to the diurnal component.  This diurnal component
   is _n_o_t considered in these forecasts, nor could it  be  easily  incor-
   porated  into  these  charts.   The charts are intended to be _g_l_o_b_a_l_l_y
   valid. Hence, the obvious diurnal enhancements which occur in  differ-
   ing ways for different regions cannot be included in this global fore-
   cast.  The  person  interested  in  radio  communications  is  already
   expected  to  have  a knowledge of the diurnal enhancements for his or
   her region.  These charts, therefore, are only  intended  to  aid  the
   interested  communications operator in determining the potential times
   when enhanced  radio  communications  may  be  possible.   It  is  not
   intended  to  reflect the diurnal enhancements which occur, unless the
   enhancements are significant.

        The forecasts are based  heavily  on  recurrent  geomagnetic  and
   auroral activity, which are primary factors in determining the quality



                               July 14, 1991





                                   - 12 -


   of radio signal propagation conditions.  The intensity  of  ionization
   of the appropriate ionospheric layers are also examined when preparing
   these charts.

        This section is separated into three charts for the high latitude
   regions,  middle  latitudes  and  the  low  latitude  regions.  Global
   separation of areas into  latitudinal  zones  is  required  since  the
   characteristics  and  quality of radio propagation differ from zone to
   zone.

        To make the best use of these charts, the  interested  reader  is
   encouraged  to  follow this procedure.  Determine the path endpoint of
   your signal.  That is, determine the  location  where  you  want  your
   transmitted  signal to be received.  This is the _p_a_t_h _e_n_d_p_o_i_n_t or _d_e_s_-
   _t_i_n_a_t_i_o_n.  Your transmitter location is the _s_t_a_r_t_p_o_i_n_t or _s_o_u_r_c_e.  Now
   draw  a  great-circle  between the startpoint and the endpoint.  Next,
   determine the most _n_o_r_t_h_e_r_l_y geographical coordinates  of  the  great-
   circle  connecting  the startpoint and the endpoint (we will call this
   point the _n_o_r_t_h_p_o_i_n_t) and note the _c_u_r_r_e_n_t _l_o_c_a_l time  at  the  north-
   point.  After calculating this information, determine what latitudinal
   zone the path northpoint lies in. Finally, consult the HF  propagation
   prediction   charts   and  select  the  latitudinal  zone  chart  that
   corresponds to the _l_a_t_i_t_u_d_e _o_f _t_h_e _p_a_t_h _n_o_r_t_h_p_o_i_n_t.  Using  the  local
   time  at  the path northpoint, select the appropriate day in the chart
   and examine the plot line which corresponds to that local time.   This
   is  the propagation quality that can be expected for that path at that
   time. Note, however, that you must also  consider  the  local  diurnal
   signal  behavior  of  your  transmission, and the local diurnal signal
   behavior at the path  endpoint  in  order  to  determine  the  diurnal
   characteristics  that  should  be  expected.   This information is not
   given in these charts, but should already be known by the radio opera-
   tor  who is familiar with the diurnal conditions which occur at his or
   her site.  In order to be most accurate, this diurnal  component  must
   be considered together with the propagation predictions. Therefore, if
   your transmission were conducted during a period of time when you know
   both  the  startpoint  and  endpoint  signals  are  enhanced,  a truer
   representation of the propagation quality may be obtained by examining
   the  prediction  charts  (using  the  method above) and increasing the
   quality of propagation up by _n_o _m_o_r_e than one level (ie.  from  "fair"
   to "good").

        For example, suppose you wanted to  communicate  between  Florida
   and  Great  Britain.  Florida is a low latitude zone and Great Britain
   is a middle-latitude zone.  Next,  we  draw  a  great  circle  between
   Florida  and  Great Britain.  If you have no numerical method of doing
   this, you can approximate the great circle path by stretching a narrow
   piece of paper on a globe of the world such that the ends of the piece
   of paper intersect the path startpoint and endpoint (the paper  should
   be  bent  so  that  one  of  its edges lays flat on the surface of the
   globe).  The path that this paper makes on the globe  will  be  curved
   and  represents  the  great-circle path between Florida and Great Bri-
   tain.  By examining the great circle path, we are able to see that the
   most  northerly geographical position on the path is at Great Britain.
   Since Great Britain is a middle-latitude region, we consult the middle



                               July 14, 1991





                                   - 13 -


   latitude  prediction chart.  If you transmitted to Great Britain at 11
   am local time on Thursday, the time at the northpoint (which is  Great
   Britain)  would  be 3 or 4 pm (depending on the season).  Since 3 or 4
   pm translates to 15:00 or 16:00 in 24-hour  clock  format,  you  would
   examine the middle plot line of the chart for Thursday. Note, however,
   that the northpoint local time of 15:00 or 16:00 falls  close  to  the
   boundary  between  the  middle  plot  line  and the last plot line for
   Thursday.  Since this is the case, a more accurate  representation  of
   conditions  may  be  obtained  by considering a mix of the middle plot
   line with the last plot line (possibly averaging the two plot lines).

        An important consideration to note when attempting to  use  these
   charts  is the time of sunrise and sunset between the startpoint, end-
   point and northpoint.  Since dramatic changes in  ionospheric  charac-
   teristics  occur  during these periods, any transmission which crosses
   the sunrise or sunset boundaries on  its  way  to  the  endpoint  will
   experience  correspondinly  dramatic  changes in behavior and quality.
   These charts do not (and could not) account for  these  variations  in
   signal quality.  The sunrise and sunset ionospheric anomalies are con-
   sidered diurnal components in this discussion.

        In many cases, the great-circle path of  the  signal  may  travel
   over  more  northerly latitudes than the startpoint and endpoint.  For
   example, a transmission between central Canada and Great  Britain  may
   result  in  a  great-circle path that passes through the high-latitude
   regions before reaching Great Britain, even though both the startpoint
   and  endpoint  are middle-latitude stations.  In these cases, the most
   northerly position of the great-circle path should be used.

        If the signal path (or the two path endpoints) are near the boun-
   daries  of two latitudinal zones, a mix of the propagation predictions
   for the two latitudinal zones may be required to yield a more accurate
   representation of propagation conditions.  For example, if a transmis-
   sion were conducted between  Denver  and  Atlantic  City,  which  both
   border  as  low  and middle latitude locations, both of the charts for
   the low and middle latitude zones should  be  analyzed  and  mixed  in
   order  to  determine  the conditions which might be expected over that
   path.  Since the distances in this latter example are relatively small
   (compared  to  the latter examples), the northpoint of the signal path
   will not significantly affect propagation conditions.  This is why  we
   only  examined  the  latitude  of  the  startpoint  and endpoint.  For
   greater distances, the northpoint must be considered.

   _2._9.  _V_H_F _P_r_o_p_a_g_a_t_i_o_n _P_r_e_d_i_c_t_i_o_n _C_h_a_r_t_s

        The prediction of potential VHF DX is not as simple as it is  for
   HF.  VHF signals have properties which are not usually affected by the
   ionospheric layers.  In our context, "VHF" will  be  considered  those
   frequencies  ranging  from  about  50 MHz to 300 MHz.  For information
   regarding the major types of VHF propagation which are possible,  con-
   sult part I of this document.

        A great deal of information can be extracted from the VHF predic-
   tion  charts.   Information  pertaining  to  HF communications is also



                               July 14, 1991





                                   - 14 -


   imbedded in these charts.  As was done for the HF  prediction  charts,
   the  VHF  predictions are separated into three charts; one for each of
   the major latitude zones.

        The upper part of the chart forecasts the  quality  of  potential
   _d_i_s_t_a_n_t  _V_H_F  _s_i_g_n_a_l_s.   It  does  _n_o_t  depict  the quality of locally
   transmitted VHF signals.  This is  an  important  point  to  remember.
   Locally  transmitted  "line  of sight" signals can not be affected and
   are not affected by geomagnetic activity, auroral activity,  or  SIDs.
   Therefore,  only  the  distant  signals which can be affected by these
   phenomena are considered in these charts.

        As was the case with the other propagation prediction charts, the
   VHF  prediction charts are separated into groups of three 8-hour daily
   intervals.  The reference of time used in these charts is _L_O_C_A_L  _t_i_m_e,
   _n_o_t  UT  time.   That  is,  the first line of each day in these charts
   represents the period between _l_o_c_a_l midnight and 8 am _l_o_c_a_l time.

        To use these charts, simply determine what time it is locally and
   examine  the  appropriate  day  in the charts and the appropriate plot
   line within that day.  The top portion of the prediction charts define
   the  quality  of  VHF  signals  which can be expected over larger dis-
   tances.  The bottom chart describes the  probability  of  experiencing
   conditions  capable  of  supporting  VHF DX.  Both charts use the same
   reference of time (local time).

        The  _S_I_D  _E_N_H_A_N_C_E_M_E_N_T  chart  at  the  upper  right-hand   corner
   describes  the  probability  of a SID (sudden ionospheric disturbance)
   temporarily enhancing VHF  communications.   The  probability  of  SID
   enhancements   increases  with  solar  activity,  but  decreases  with
   increasing latitude.  This data is also  of  value  to  the  HF  radio
   operator,  since  SIDs  almost  always produce short-wave fades (SWFs)
   which can disrupt HF communications.  Since SIDs are sporadic and very
   unpredictable  (due to the unpredictable nature of solar flares), they
   are  predicted  as  percentages  in  these  charts.   SID-related  VHF
   enhancements  _d_o  _n_o_t occur on the dark-side of the earth.  Neither do
   SWFs.  Therefore, these SID prediction  charts  _o_n_l_y  apply  to  those
   locations which are still well illuminated by the sun.

        The _A_U_R_O_R_A_L _B_A_C_K_S_C_A_T_T_E_R prediction charts are of value to the VHF
   radio operator.  Auroral backscattering (as was described in part I of
   this  document)  is  possible  at  VHF  frequencies  during  times  of
   increased  geomagnetic  and auroral activity.  These prediction charts
   define the approximate probabilities of VHF  propagation  via  auroral
   backscatter  over  the  various latitudes.  VHF signals which are pro-
   pagated via aurorae can travel fairly  large  distances.   Propagation
   via  aurorae  is  therefore considered a potential method of DX on VHF
   frequencies.  It is, however, a fairly local  and  sporadic  phenomena
   and  is  usually  not  a  widely-encountered form of propagation until
   auroral and geomagnetic activity reaches significant storm levels.

        To make use of these VHF charts, simply consult  the  appropriate
   plot  lines  according  to  what day it is and the local time.  The HF
   operator may be able to determine what days will prove  less  reliable



                               July 14, 1991





                                   - 15 -


   as  far  as day-time propagation goes by examining the probability for
   SID related SWFs.  Most SWFs, however, are only temporary and  do  not
   pose  a  significant  threat  to  most HF operators, unless the flares
   which produce them are particularly intense.

   _2._1_0.  _A_u_r_o_r_a_l _A_c_t_i_v_i_t_y _P_r_e_d_i_c_t_i_o_n_s

        Auroral activity is predicted for the three major latitude  zones
   identified  earlier.  Since the auroral oval itself is situated within
   the high-latitude zone, the high latitudes will  naturally  experience
   significantly more auroral activity than the middle and low latitudes.

        The prediction charts for auroral activity  are  most  useful  to
   those  people  interested  in  either observing auroral activity, pro-
   pagating radio signals using aurorae,  or  for  people  interested  in
   determining  the  extent of magnetic fluctuations occurring near areas
   of auroral activity.

        Since auroral activity migrates  equatorward  during  geomagnetic
   storms,  locations  which  may  usually be outside of the auroral zone
   itself may occasionally find themselves _i_n_s_i_d_e the auroral zone during
   periods  of  increased  geomagnetic  activity.   Likewise,  as auroral
   activity shifts equatorward, low latitudes may be able to begin  spot-
   ting the activity.

        These prediction charts can be used to determine whether  or  not
   potential  auroral  activity  may  be intense enough to be seen at low
   latitudes, or whether auroral activity will be dull  and  inactive  or
   bright and very active.

        To use the charts, simply examine the appropriate chart  (ex.  if
   you're  a middle latitude location, examine the middle-latitude chart)
   and select the column on the day you are most interested.   The  first
   plot line of each day represents the evening twilight period.  This is
   the period between when the sun sets and  before  the  sky  gets  com-
   pletely  dark.   The  second  plot line represents the midnight sector
   where the sky remains completely  dark  (excluding  effects  of  lunar
   phase).   The  last  plot  line  is  the  morning  twilight period and
   represents the time when the sky just barely begins to brighten  until
   the sun rises.

        The phase of the moon is not taken into  consideration  in  these
   charts.   The  moon  can  have  a profound effect on the visibility of
   auroral activity, but does not affect auroral activity  itself.   That
   is,  just  because  the  moon  may  be  blocking  out light of auroral
   activity does not mean that  auroral  activity  is  not  in  progress.
   Indeed,  intense auroral storms can occur during a full moon as easily
   as they can during new moons.  Therefore, these charts  represent  the
   occurrence of auroral activity regardless of lunar phase.

        The intensity  of  auroral  activity  is  measured  according  to
   several  parameters.   Each  of  these parameters are discussed in the
   Glossary of Solar Terrestrial Terms.  In their most  basic  form,  the
   parameters   (low,   moderate,  high,  etc.)  may  be  considered  the



                               July 14, 1991





                                   - 16 -


   brightness of auroral activity during dark-sky conditions (ie. periods
   of  new  moon).   However,  actual visual movements, color changes and
   aerial extent are also considered when classifying auroral activity in
   these prediction charts.



   _3.  _M_o_n_t_h_l_y _S_o_l_a_r _T_e_r_r_e_s_t_r_i_a_l _R_e_v_i_e_w

        Every month, statistics and information regarding solar and  ter-
   restrial  activity  for  the preceding month are gathered and compiled
   into a document called the _M_o_n_t_h_l_y  _S_o_l_a_r  _T_e_r_r_e_s_t_r_i_a_l  _R_e_v_i_e_w.   This
   document  contains  not  only  information  regarding  the  nature  of
   activity of solar  and  geophysical  phenomena  during  the  preceding
   month, but also includes a six month solar cycle outlook.  This can be
   of great value to the radio operator who is interested in  determining
   what  conditions  might be like six months down the road.  It can also
   be of interest to the astronomer who may enjoy searching  for  auroral
   activity or solar flares.

        In addition to the written summary, a statistical summary of  the
   previous  month is given in tabular form, summarizing all of the major
   solar parameters (ie.  solar  flux,  sunspot  numbers,  active  region
   sizes, numbers and types of flares, etc.).

        This report is intended to serve as a general  summary  regarding
   activity  and phenomena encountered during the previous month.  It can
   provide some interesting results if data from the report is charted or
   graphed or statistically analyzed.



   _4.  _G_e_o_m_a_g_n_e_t_i_c _S_t_o_r_m _A_l_e_r_t

        This alert is posted over the nets whenever magnetic storm condi-
   tions  reach or exceed minor storm levels over middle latitudes.  This
   alert may be preceded by a warning if a magnetic storm is expected  to
   occur but hasn't yet begun.

        These alerts always summarize the current level of  activity  and
   may  also  include  descriptions  of  outstanding geomagnetic activity
   occurring prior to the time the alert was issued.

        A brief textual forecast of the expected geomagnetic activity  is
   also  included  with  these  reports.   This  effectively serves as an
   intermediate forecast which can be of value during  geomagnetic  storm
   periods when conditions change rapidly.

        Full HF and VHF summaries are included with the storm alerts  and
   all following storm information updates.  This information is of value
   to those who rely on  ionospheric  and/or  auroral-related  communica-
   tions.





                               July 14, 1991





                                   - 17 -


   _5.  _A_v_a_i_l_a_b_i_l_i_t_y _o_f _A_d_d_i_t_i_o_n_a_l _S_e_r_v_i_c_e_s

        Solar Terrestrial Dispatch also supplies other services not  men-
   tioned  in this document, which may be of interest or value to certain
   individuals or organizations.  One of the additional services provided
   are GIC forecast and warning services for individuals or organizations
   requiring predictions of  possible  Geomagnetically  Induced  Currents
   caused  by  magnetic  storming  over the high and/or middle latitudes.
   Forecasts are produced on a weekly  basis,  and  warnings  are  issued
   whenever conditions (or expected conditions) warrant.

        For more information on this or other services not  mentioned  in
   this  document,  feel  free  to  contact Solar Terrestrial Dispatch by
   writing to: Solar Terrestrial Dispatch,  Box  357,  Stirling,  Alberta
   Canada,  T0K  2E0.  Alternatively, for those of you with access to one
   of the large electronic networks, you  may  contact:  [e-mail]
   for more information (this is an Internet address).

        Significant enhanced services will soon be available  from  Solar
   Terrestrial  Dispatch  for  individuals  and researchers interested in
   obtaining up-to-the-minute solar terrestrial  data  (ex.  x-ray  data,
   proton  data,  geomagnetic data, flare-related data, ionospheric data,
   etc).  For more information or questions regarding the availability of
   these  or  other services, consult Solar Terrestrial Dispatch as given
   above.

        A recent addition to the services provided by the  Solar  Terres-
   trial  Dispatch  is the Solar Terrestrial Dispatch computer BBS.  This
   is a public-access BBS system which regularly obtains fresh  forecasts
   and  data  sets.   A  great  deal  of  additional data is available to
   registered users of this BBS, including ionospheric data (total  elec-
   tron  content  data, MUF forecasts, short-wave fade forecasts and much
   more), geomagnetic  data  (real-time  geomagnetic  data  less  than  2
   minutes  old,  indices  and  forecasts, etc) and access to other solar
   forecasts and data sets (such as real-time x-ray plots, proton  plots,
   polar  cap  absorption  plots,  etc).   These  are  all  available  to
   registered users of the BBS.  Registration information may be found by
   calling  the BBS.  The phone number is: [phone].  Baud rates of
   300, 1200 or 2400 baud are accepted.  The communications protocol is 8
   bit  words,  1 stop bit and no parity.  Unregistered users are able to
   access all of the information which is available  over  the  Internet,
   Bitnet and Usenet networks.



   _6.  _C_o_n_c_l_u_d_i_n_g _R_e_m_a_r_k_s

        The solar terrestrial reports which are posted over the  networks
   contain a great deal of information.  Understanding them may take some
   time.  Applying the  information  contained  in  them  may  take  even
   longer.   This  document (part I and II) was developed to help explain
   the nature and format of these reports.  It was also developed to help
   those  who are interested in interpreting and applying the information
   contained in the reports.



                               July 14, 1991





                                   - 18 -


        It is hoped that this document will help those who are interested
   in  better  understanding  the  solar  terrestrial reports.  Questions
   and/or comments are welcome.  If any further explanations are required
   which  have not been adequately covered in this document, feel free to
   send an inquiry to  "[e-mail]"  or  leave  a  message  to  the
   "Sysop" on our BBS.

        We have learned a great deal over the years regarding the impacts
   of  solar  activity  on  our terrestrial sphere.  But there is still a
   great deal more we need to learn before we can expect  to  master  the
   art  of  predicting  the  impacts of solar activity on the earth.  Our
   curiosity drives us further and our lust for  knowledge  quickens  our
   pace of learning.  With developements of new devices and technologies,
   we are steadily edging closer to understanding  both  our  terrestrial
   environment and the vast environment of space.  The educational insti-
   tutions and research organizations are the backbones of our  knowledge
   and  growth.   We  must  therefore respect these institutions, support
   them, and encourage them so that our body of knowledge is able to con-
   tinue expanding into the limitless realm of science.






































                               July 14, 1991





                                   - 19 -





                             Table of Contents




   Introduction ....................................................    1

   The Solar Terrestrial Forecast and Review .......................    2

   Summary of Solar Terrestrial Activity ...........................    2

   Short Term Solar Terrestrial Forecast ...........................    5

   Solar Region Summary ............................................    6

   Geomagnetic Activity Summary ....................................    8

   10-Day Geomagnetic Activity Forecast ............................    9

   Graphical Analysis of Solar Activity ............................    9

   20-Day Solar Activity Forecast ..................................   10

   HF Radio Signal Propagation Predictions .........................   10

   VHF Propagation Prediction Charts ...............................   13

   Auroral Activity Predictions ....................................   15

   Monthly Solar Terrestrial Review ................................   16

   Geomagnetic Storm Alert .........................................   16

   Availability of Additional Services .............................   17

   Concluding Remarks ..............................................   17


















                               July 14, 1991