NOAA SEC Report of Solar-Geophysical Activity 24 Mar 2002

:Product: Report of Solar-Geophysical Activity

:Issued: 2002 Mar 24 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 083 Issued at 2200Z on 24 Mar 2002

IA.  Analysis of Solar Active Regions and Activity from  23/2100Z

to 24/2100Z:  Solar activity remained at low levels. Region 9876

(S15E18) produced a long-duration C5/Sf flare at 24/1754 UTC. This

region showed a minor spot increase near its leader spots, but

showed an overall decrease in area due to a decrease in penumbral

coverage in its trailer spots. It remained moderately complex with

mixed polarities within its trailer portion. Region 9881 (S03W34)

showed minor spot growth and produced a C4/Sf flare at 24/2036 UTC.

Spot growth was also observed in Region 9880 (N07W08), but it

produced no optical flares. Region 9878 (N09E28) retained moderate

magnetic complexity, but showed no significant changes.

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

low to moderate levels. There’s a fair chance for isolated,

low-level M-class activity during the period.

IIA.  Geophysical Activity Summary 23/2100Z to 24/2100Z:

Geomagnetic field activity increased to active to major storm levels

during 24/0200 – 1200 UTC. Field activity decreased to active to

minor storm levels during 24/1200 – 1800 UTC, then decreased to

mostly unsettled levels for the rest of the period. The increase in

activity coincided with a period of sustaes southward IMF Bz

(maximum southerly deflections to minus 12 nT (GSM), as measured by

NASA’s ACE spacecraft). The greater than 10 MeV proton event that

began at 22/2020 UTC ended at 23/2030 UTC. The peak flux for this

event was 16 pfu at 23/1320 UTC.

IIB.  Geophysical Activity Forecast:  Geomagnetic field activity is

expected to be at unsettled to active levels on 25 March. Quiet to

unsettled conditions are expected during the rest of the period.

III.  Event Probabilities 25 Mar-27 Mar

Class M    40/40/40

Class X    05/05/05

Proton     01/01/01

PCAF       green

IV.  Penticton 10.7 cm Flux

Observed           24 Mar 175

Predicted   25 Mar-27 Mar  170/165/165

90 Day Mean        24 Mar 210

V.  Geomagnetic A Indices

Observed Afr/Ap 23 Mar  008/009

Estimated Afr/Ap 24 Mar  035/050

Predicted Afr/Ap 25 Mar-27 Mar  015/020-010/010-010/010

VI.  Geomagnetic Activity Probabilities 25 Mar-27 Mar

A.  Middle Latitudes

Active                30/25/25

Minor storm           10/05/05

Major-severe storm    05/01/01

B.  High Latitudes

Active                35/30/30

Minor storm           15/10/10

Major-severe storm    10/01/01