NOAA SEC Report of Solar-Geophysical Activity 23 Mar 2002

:Product: Report of Solar-Geophysical Activity

:Issued: 2002 Mar 23 2210 UTC

# Prepared jointly by the U.S. Dept. of Commerce, NOAA,

#Space Environment Center and the U.S. Air Force.

#

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 082 Issued at 2200Z on 23 Mar 2002

IA.  Analysis of Solar Active Regions and Activity from  22/2100Z

to 23/2100Z:  Solar activity decreased to low levels. Frequent

C-class flares occurred. Region 9876 (S16E30) was the most active

area on the disk and produced occasional C-class subflares. It grew

during the period with increased area and magnetic complexity,

particularly in its trailer spots. Region 9878 (N10E43) produced a

long-duration C2/Sf flare at 23/0330 UTC with no significant radio

emission. This region grew at a gradual pace with a minor increase

in area and spot count. Region 9871 (S18W60) produced an isolated

subflare as it continued to gradually decay. New Region 9883

(N06E67) was numbered.

IB.  Solar Activity Forecast:  Solar activity is expected to be low

to moderate. There is a fair chance for an M-class flare from Region

9876. Major flare potential may increase in this region if its

current rate of growth continues.

IIA.  Geophysical Activity Summary 22/2100Z to 23/2100Z:

Geomagnetic field activity was at quiet to active levels. Field

activity increased to unsettled to active levels following a sudden

impulse at 23/1137 UTC (16 nT, as measured by the Boulder USGS

magnetometer). The greater than 10 MeV proton event that began at

22/2020 UTC continued. The preliminary maximum for this event was

16.2 pfu at 23/1320 UT.

IIB.  Geophysical Activity Forecast:  Geomagnetic field activity is

expected to be at quiet to unsettled levels during most of the

period. However, brief active conditions may occur during 25 – 26

March. The greater than 10 MeV proton event is expected to end early

in the period.

III.  Event Probabilities 24 Mar-26 Mar

Class M    40/40/40

Class X    05/05/05

Proton     50/01/01

PCAF       Yellow

IV.  Penticton 10.7 cm Flux

Observed           23 Mar 170

Predicted   24 Mar-26 Mar  170/165/165

90 Day Mean        23 Mar 211

V.  Geomagnetic A Indices

Observed Afr/Ap 22 Mar  007/008

Estimated Afr/Ap 23 Mar  010/010

Predicted Afr/Ap 24 Mar-26 Mar  010/012-010/015-010/012

VI.  Geomagnetic Activity Probabilities 24 Mar-26 Mar

A.  Middle Latitudes

Active                25/25/25

Minor storm           10/10/05

Major-severe storm    05/05/01

B.  High Latitudes

Active                30/30/25

Minor storm           15/15/10

Major-severe storm    05/05/01