Daily Report

(last updated 21 Sep 2019 23:34 UT)

SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT ISSUED AT 2330UT/21 SEPTEMBER 2019 BY Space Weather Services FROM THE AUSTRALIAN SPACE FORECAST CENTRE SUMMARY FOR 21 SEPTEMBER AND FORECAST FOR 22 SEPTEMBER - 24 SEPTEMBER STATUS INDICATORS SOL:GREEN MAG:GREEN ION: GREEN ----------------------------------------------------------- 1A. SOLAR SUMMARY Activity 21 Sep: Very low Flares: none. Observed 10.7 cm flux/Equivalent Sunspot Number for 21 Sep: 68/2 1B. SOLAR FORECAST 22 Sep 23 Sep 24 Sep Activity Very low Very low Very low Fadeouts None expected None expected None expected 10.7cm/SSN 68/2 68/2 68/2 COMMENT: Solar activity remained very low on UT day 21 September with no active regions on the visible disc. No active regions are expected to rotate onto the visible disc and very low solar activity is expected for the next three UT days, 22-24 September. During UT day 21 September, the solar wind speed showed a quick rise from 300 km/s to 364 km/s between 03.56 and 06.21 UT and then stayed between 340 km/s and 360 km/s during the rest of the day. The total IMF (Bt) increased from 3 nT to 7 nT by 06.03 UT and then varied between 2 and 6 nT during the remaining day, Bz turned south to -6.2 around 05.47 UT and the particle density increased from 4 to 12 ppcc around 06.00 UT. These observations seem to support the arrival of a slow and weak CME that was observed on 16 September. Solar wind stream is expected to stay at nominal levels on UT day 22 September and then show some strengthening on UT days 23 and 24 September due to the effect of a coronal hole. ----------------------------------------------------------- 2A. MAGNETIC SUMMARY Geomagnetic field for Australian Region 21 Sep: Quiet Estimated Indices 21 Sep : A K Australian Region 4 11222201 Cocos Island 2 11111200 Townsville 5 11222211 Learmonth 5 22222201 Alice Springs 4 11222200 Gingin 5 21222201 Canberra 3 01222200 Launceston 6 12223201 Hobart 4 12222200 Estimated Antarctic Regional K Indices 21 Sep : Macquarie Island 8 02244100 Casey 8 23321212 Mawson 20 32332255 Observed Regional daily pc3 Indices 21 Sep : Darwin 0 (Quiet) Townsville 0 (Quiet) Learmonth 0 (Quiet) Alice Springs 0 (Quiet) Gingin 0 (Quiet) Canberra 0 (Quiet) Melbourne NA Pc3 pulsations are high frequency (10-45 second period) variations of the Earths magnetic field. Daily pc3-indices are the daily sum of 20 minute pc3-indices for that station and have been shown to be well correlated with rejection of high resolution aeromagnetic survey flight-line data. NOTE: Indices may have been generated from data obtained in cooperation with the following organisations: Geoscience Australia, University of Newcastle Space Physics Group, Australian Government Antarctic Division and International Center for Space Weather Science and Education, Japan. Estimated AFr/Ap Indices 21 Sep : A Fredericksburg 7 Planetary 8 Observed AFr/Ap Indices 20 Sep : A K Fredericksburg 3 Planetary 4 2010 1121 2B. MAGNETIC FORECAST Date Ap Conditions 22 Sep 5 Quiet 23 Sep 10 Quiet to unsettled, some active periods possible 24 Sep 12 Unsettled to Active COMMENT: Quiet levels of geomagnetic activity were recorded in the Australian region on UT day 21 September. Mostly quiet to unsettled conditions were observed in the Antarctic region with isolated active and minor storm periods. Global geomagnetic activity is expected to be mostly at quiet levels on UT day 22 September and then rise to unsettled and active levels on 23 and 24 September due to the effect of a coronal hole. ----------------------------------------------------------- 3A. GLOBAL HF PROPAGATION SUMMARY Latitude Band Date Low Middle High 21 Sep Normal Normal Normal-fair PCA Event : No event. 3B. GLOBAL HF PROPAGATION FORECAST Latitude Band Date Low Middle High 22 Sep Normal Normal Normal 23 Sep Normal Normal-fair Normal-fair 24 Sep Normal Normal-fair Normal-fair COMMENT: Maximum usable frequencies (MUFs) were mostly near predicted monthly values during UT day 21 September. Some periods of minor to moderate MUF enhancements as well as MUF depressions were also observed in some low- and mid-latitude regions. Sporadic-E and Spread-F occurrences were observed over some sites. For the next three UT days, 22-24 September, MUFs are expected to be mostly near predicted monthly values with the possibility of minor to moderate MUF depressions on UT days 23 and 24 September. ----------------------------------------------------------- 4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY Date T index 21 Sep -4 Observed Australian Regional MUFs Niue Island Region: Mostly near predicted monthly values. Depressed by 25% after local dawn. Northern Australian Region: Near predicted monthly values during local day. Depressed by 25% during local night. Southern Australian Region: Near predicted monthly values during local day. Enhanced by 15% during local night. Enhanced by 25% after local dawn. Antarctic Region (Casey/Scott Base/Davis/Mawson): Enhanced by 20% over the UT day. Monthly T index: Month T index Aug -3 Sep -14 Oct -16 4B. AUSTRALIAN REGION IONOSPHERIC FORECAST Date T index MUFs 22 Sep -2 Near predicted monthly values 23 Sep -4 Near predicted monthly values/depressed 10 to 20% 24 Sep -5 Near predicted monthly values/depressed 10 to 20% COMMENT: Maximum usable frequencies (MUFs) in the Australian region were mostly near predicted monthly values during UT day 21 September. Some periods of minor to moderate MUF enhancements as well as MUF depressions were also observed. Sporadic-E and Spread-F occurrences were observed over some sites. For the next three UT days, 22-24 September, MUFs are expected to be near predicted monthly values with the possibility of minor to moderate MUF depressions on UT days 23 and 24 September. ----------------------------------------------------------- 5. SPACE ENVIRONMENT SUMMARY GOES satellite data for 20 Sep Daily Proton Fluence >1 MeV: 4.2E+05 Daily Proton Fluence >10 MeV: 2.2E+04 Daily Electron Fluence >2 MeV: 4.90E+07 (normal fluence) Electron Fluence Daily Deep Dielectric Discharge Probability: 7% Fluence (flux accumulation over 24hrs)/ cm2-ster-day. X-ray background: A3.4 DSCOVR Satellite Solar Wind Day Averaged Data for 20 Sep Speed: 312 km/sec Density: 3.5 p/cc Temp: 32800 K Bz: -1 nT (Courtesy Space Weather Prediction Center, Boulder USA) -----------------------------------------------------------