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From: oler@rho.uleth.ca (Cary Oler)
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Subject: Monthly Review of Solar & Geophysical Activity for July 1993
To: solar-monthly@lut.fi
Date: Mon, 16 Aug 93 17:34:27 MDT
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           --  MONTHLY REVIEW OF SOLAR AND GEOPHYSICAL ACTIVITY  --
                            Summary for July 1993

                            Report compiled by the
                          Solar Terrestrial Dispatch
                                 P.O. Box 357
                              Stirling, Alberta
                               T0K 2E0, Canada
 
                    Data Provided In-Part Courtesy of the
                   Space Environment Services Center, NOAA
                                   and the
                NRC / Dominion Radio Astrophysical Observatory
                     Penticton, British Columbia, Canada


MONTHLY ACTIVITY SUMMARY FOR JULY 1993

     We are now in month 83 of solar cycle 22 (as of July 1993).  There
were 202 flares (optical and x-ray) in July.  This is a decrease of 38% over
the number of events observed in June.  No major flares were recorded and
only 4 reached M-class levels.  All of the observed M-class flares erupted
from Region 7530 between 02 and 04 July.

     A breakdown of the energetic events for the last four months follows
below.
         ____________________________________________________________
        |                    | JUL '93 | JUN '93 | MAY '93 | APR '93 |
        |                    | --------|---------|---------|---------|
        |              Major |      0  |     3   |     0   |     1   |
        |      Minor M-class |      4  |    10   |     5   |     2   |
        | Class C or smaller |    198  |   315   |   280   |   328   |
        |--------------------|---------|---------|---------|---------|
        |              Total |    202  |   328   |   285   |   331   |
         ------------------------------------------------------------

     The monthly sunspot number for July was 81.6 as computed by the
SESC.  The preliminary RI international sunspot number for July was 57.3.
This is an increase over June's values of 68.5 and 49.1 respectively and is
the only monthly increase that has been recorded since February of this year.
The preliminary smoothed international sunspot number centered on January of
this year was 71.3.

     The monthly 10.7 cm solar radio flux for July was 99.0 which
results in a preliminary smoothed mean flux value of 125.6 centered on
January 1993.  The monthly mean solar flux adjusted to 1 AU was 102.2.  The
best absolute value of the estimated 10.7 cm solar radio flux for the month
was 92.0 (Series D).

     The largest flare of July occurred on 02 July from Region 7530.  The
event reached a maximum M4.3/2B flare class at 13:21 UTC and was associated
with a 400 sfu tenflare at 13:14 UTC.  There were no spectral radio sweeps
reported with this event.

     The most eruptive region during July was Region 7530 (also numbered as
Region 7518 early in June during its first rotation).  This region departed
the west limb on 07 July in a weakened and decaying state.  During its active
lifetime, Region 7530/7518 was responsible for 140 optically correlated
flares, or a significant 26 percent of all of the events observed during June
and July combined.  On 23 July, new Region 7553 was numbered as a small
single sunspot imbedded within the returning fields of Region 7530.  The
region had decayed significantly, but slowly, as it traversed the far side of
the Sun.  Significant renewed growth was observed in this region on 27 July
from a simple AXX type spot on 26 July to a DSI-type group encompassing 15
new spots on 27 July.  The region became a DAO-type group as growth slowed on
28 July.  The region remained relatively stable until 31 July when the fields
within this region showed moderate decay.  At the time of this writing, the
group decayed to spotless plage on 03 August approximately one day before
departing the west limb.  The fields associated with this region are due back
around 17 or 18 August.  Yohkoh x-ray observations on 16 August show an area
of modest activity near S12 on the east limb that may be related to this area
of regenerative flux that has been known as Regions 7518, 7530, and 7553.

     There were no proton enhancements at greater than 10 MeV during July.

     The list of minor M-class or greater flares and associated radio
emissions observed during July follows:


SUMMARY OF MAJOR ENERGETIC EVENTS
---------------------------------

 Date   Begin  Max   End  Xray  Op Region  Locn    2695 MHz  8800 MHz  15.4 GHz
------  ----  ----  ----  ----  -- ------ ------  --------- --------- ---------
NO MAJOR ENERGETIC EVENTS OBSERVED.


SUMMARY OF MINOR M-CLASS EVENTS
-------------------------------

 Date   Begin  Max   End  Xray  Op Region  Locn    2695 MHz  8800 MHz  15.4 GHz
------  ----  ----  ----  ----  -- ------ ------  --------- --------- ---------
02 Jul: 1311  1321  1326  M4.3  2B  7530  S11W14       400       730       600
03 Jul: 1036  1102  1110  M1.6  1N  7530  S13W26
04 Jul: 0740  0750  0756  M1.6  1B  7530  S16W38        25       100        89
        1102  1129  1242  M1.8  2B  7530  S11W37


REGION FLARE STATISTICS
-----------------------

                C   M   X     S   1   2   3   4   Total   (%)
               --  --  --    --  --  --  --  --    ---  ------
  Region 7530:  5   4   0    27   2   2   0   0    031  (15.3)
  Region 7531:  1   0   0     1   0   0   0   0    001  ( 0.5)
  Region 7534:  0   0   0     5   0   0   0   0    005  ( 2.5)
  Region 7537:  1   0   0     2   0   0   0   0    002  ( 1.0)
  Region 7538:  0   0   0     1   0   0   0   0    001  ( 0.5)
  Region 7540:  0   0   0     1   0   0   0   0    001  ( 0.5)
  Region 7542:  0   0   0     4   0   0   0   0    004  ( 2.0)
  Region 7543:  0   0   0     9   0   0   0   0    009  ( 4.5)
  Region 7544:  0   0   0     1   0   0   0   0    001  ( 0.5)
  Region 7545:  0   0   0     3   0   0   0   0    003  ( 1.5)
  Region 7546:  0   0   0     1   0   0   0   0    001  ( 0.5)
  Region 7547:  0   0   0     1   0   0   0   0    001  ( 0.5)
  Region 7548:  1   0   0     6   1   0   0   0    007  ( 3.5)
  Region 7549:  0   0   0     2   0   0   0   0    002  ( 1.0)
  Region 7550:  0   0   0     7   0   0   0   0    007  ( 3.5)
  Region 7551:  0   0   0     2   0   0   0   0    002  ( 1.0)
  Region 7552:  0   0   0     8   0   0   0   0    008  ( 4.0)
  Region 7553:  0   0   0     4   0   0   0   0    004  ( 2.0)
  Region 7555:  1   0   0     4   2   0   0   0    006  ( 3.0)
Uncorrellated: 14   0   0     1   0   0   0   0    106  (52.5)

     The geomagnetic field was less active in July than June. The estimated
planetary A-index for July was 10, compared with 13 for June. This gives an
estimated smoothed value of 16.1 centered on January 1993. The only recorded
sudden magnetic impulse of July was a 31 nT shock at 10:28 UTC on 06 July.
The geomagnetic field became briefly unsettled before quickly returning to
quiet levels.  This shock was preceded by a 9 hour period of very quiet
conditions (K-indices of zero at Boulder), and about 21 hours of quiet
conditions with K-indices at Boulder of 1 or less.  The source of the shock
is not clear, but may have been related to a suspected coronal mass ejection
associated with the long-duration (100 minutes) M1.8/2B flare from Region
7530 at 11:29 UTC on 04 July.

     The most active days of the month were 02 and 11 July.  The estimated
planetary A-indices for these days were 25.  The disturbance of 02 July was
associated with an isolated negative polarity coronal hole.  The disturbance
of 11 July appears to have been associated with a positive polarity coronal
hole.  Yohkoh x-ray imagery showed a narrow tran

