_ falian GEOMAGNETISM REPORT

Transcription

1 blications compactus w u t; n :0 o c r ir. iifc _ falian GEOMAGNETISM REPORT MAGNETIC OBSERVATORIES VOLUME 40 No.6 JUNE 1992 BUREAU OF MINERAL RESOURCES, GEOLOGY & GEOPHYSICS

2 DEPARTMENT OF PRIMARY INDUSTRIES AMD ENER6V Minister for Resources: The Hon. Alan Griffiths MP BUREAU OF MINERAL RESOURCES, OEOIiOGY AND QEOPHYSICS EXECUTIVE DIRECTOR: R.W.R. Rutland AO, FTS This report was prepared by: Geomagnetism Section Geophysical Observatories & Mapping Program Minerals & Environment Group CHIEF OF DIVISION : D. Denham AM For further Information write to: GEOMAGNETISM SECTION BUREAU OF MINERAL RESOURCES G.P.O. Box 378 CANBERRA, A.C.T., 2601 AUSTRALIA. BMR GEOLOGY AND GEOPHYSICS A U S T R A L I A Published for the B.M.R.G. & G. by the Australian Government Publishing Service ISSN Commonwealth of Australia 1992

3 CONTENTS Page Contributing Observatories & Instrumentation 4 New Magnetic Observatory at Alice Springs... 5 K-Indices 6 Principal Magnetic Storms 10 Preliminary Monthly Mean Values 11 International Quiet & Disturbed Days 11 Sudden Storm Commencements and Solar Flare Effects 12 The observers at Casey, Davis and Macquarie Island are officers of the Antarctic Division, of the Department of the Arts, Sport, the Environment & Territories. Their contributions are gratefully acknowledged. These observers and the Bureau of Mineral Resources' (BMR) geophysicist at Mawson are members of the Australian National Antarctic Research Expedition (ANARE). Data from the Port Moresby Geophysical Observatory are contributed by the Geological Survey of Papua New Guinea. The terminology used in this report is that accepted by the International Association of Geomagnetism and Aeronomy (laga). The unit of field intensity is the nanotesla (nt). All times are in Universal Time (UT).

4 CONTRIBOTING OBSERVATORIES OBSERVER GEOGRAPHIC GEOMAGMBTIC OBSERVATORY IM CHARGE LAT. LONG. LAT. LONG. PORT MORESBY I.D.Ripper 9 25'S 'E CHARTERS TOWERS J.M.Millican 20 05'S 'E LEARMONTH M.W.McMullan 22 13'S 'E ALICE SPRINGS W. Serone 23 45'S 'E GNANGARA P.J.Gregson 31 47'S 'E CANBERRA P.A.Hopgood 35 19'S 'E MACQUARIE IS. R.Jones 54 30'S 'E MAWSON J.L.Jamieson ev- 3e'S 62 53'E DAVIS D.Neudegg es" 35'S 77 58'E CASEY N.Mifsud ee 17'S 'E Geomagnetic co-ordinates based on the 1980 DGRF Geomagnetic North pole position of N, E. MAGMETOGRAPHS CODE ELEMEtre/SCaLB-VftLOB PORT MORESBY PMG La Cour (A) H/3 D/5 Z/4 CHARTERS TOWERS CTA EDA/Elsec (D/1) X Y Z LEARMONTH LRM EDA/Elsec (D/1) X Y Z GNANGARA GNA Elsec (D/. 1) D I F CANBERRA CNB Elsec (D/..1) D I F MACQUARIE IS. MCQ PEM (D/. 1) X Y Z MAWSON MAW PEM (D/, 1) X Y Z ALICE SPRINGS *ASP* NAROD 3F/G (D/,,025) X Y Z A = analogue, 20mm/hr, scale values in nt/mm D/1 = digital, 1 minute readings, 1 nt resolution D/.l = digital, 1 minute readings, 0.1 nt resolution PEM = BMR Photo-electronic magnetograph NAROD 3F/G = NAROD 3 component ring core fluxgate magnetometer MAGNETOMETERS Absolute data are based on observations made with QHM's, BMZ's, fluxgate-theodolites, declinometers, proton vector magnetometers, proton precession magnetometers and three component fluxgate magnetometers. Errors in preliminary values obtained from magnetograms are not likely to exceed 5 nt or 0.5 minutes of arc.

5 NEW MAGNETIC OBSERVATORY AT ALICE SPRINGS A new magnetic observatory came into operation in June 1992 at Alice Springs in the Northern Territory, Australia. Coordinates of the Alice Springs observatory are: Geodetic latitude : 23' 45.7' S longitude : ' E elevation: 557 metres. Geomagnetic latitude : 33.7 S longitude : E. The geodetic coordinates are based on the Australian National Spheroid. The geomagnetic coordinates are computed for DGRF 1980 north geomagnetic pole (at N, E). The approved laga code for the observatory is ASP. The new observatory is operated by the Bureau of Mineral Resources, Geology and Geophysics (BMR), and is located on the CSIRO's Division of Wildlife and Rangelands Research Station just south of Alice Springs. The observatory is located on an alluvial plain over Tertiary sediments overlying late Proterozoic carbonates and quarzites. Equipment installed at the observatory include a three-component ring-core fluxgate to measure X, Y and Z, and an Overhauser-effect magnetometer to measure F. Calibration of the variometer is carried out weekly using a Declination Inclination fluxgate theodolite to measure D and I, and a proton precession magnetometer to measure F. The ring-core variometer is sampled every second, and the Overhauser every ten seconds. Data are averaged and recorded on an IBM compatible computer as minute values. The data are telemetered daily to BMR, Canberra and will be published in the Australian Geomagnetism Report starting from this month.

6 MAGNETIC K-INDICES - JDKE 1992 Range for lower limit of K=9 is 300nT DAY K-INDICES K-SDH _ Mean of K-Sum Is 18.0 Frequency of K-Indices K S O f!

7 QMAMGARa MAGNETIC K-INDICE8 - JUNE 1992 Range for lower limit of K=9 is 450nT DAY K-INDICES K-8UH Mean of K-Sum is 14.7 Frequency of K-Indices K! f!

8 CaMBERRR MRGNETIC K-INDICES - JUNE 1992 Range for lower limit of K=9 is 450nT DAY K-mOICES K-80M Mean of K-Stm is 14.2 Frequency of K-Indlces Ks f!

9 MAWSON MAGNETIC K-INDICES - JUNE 1992 Range for lower limit of K=9 is ISOOnT DAY K-INDICES K-SUH Mean of K-Sum is 26.2 Frequency of K-Indices KS f!

10 PRIMCIPRL MAGNETIC STORMS - JDME 1992 OBSSRVaTORX ComMencem< mt ssc -amplitude Max. 3hr K-lnd< Ranges UT End Day Hr Min Type DC) H(nT) Z(nT) Day (3hr-period) K D(-) H(nT) z{nt) Day Hr Port Moresby ssc* +0. B* (2,3,4) > «24(2) (3) Gnangara (5) (7,8) Canberra (1,3,6) (5,6)

11 JDME 1992 PRELIMIMARY MONTHLY MEAN VALUES OBSERVATORY H D z F nt deg min nt nt PORT MORESBY ,.7 ' E CHARTERS TOWERS ' E T.EARMONTH ' W ALICE SRINGS ' E GNANGARA ' W CANBERRA ' E MACQUARIE IS ' E MAWSON ' W DAVIS ' W CASEY ' W The values are derived from magnetograms over the Quietest 5 International Days, except at Mawson, Davis and Casey, where the locally quietest days are used. INTERNATIONAL ODIET AND DISTURBED DAYS Quietest days (1-5): Quietest days (6-10) : Most Disturbed days :

12 SUDDEN STORM COMMENCEMENTS (SSC)S JUNE 1992 Type Sense and Amplitude Observatory Day and U.T. of Chief Movement Quality H(nT) D(nT) 2(nT) PORT MORESBY 10 SSC*A * SSC B GNANGARA Nil ssc's observed CANBERRA 10 ssc*b * SOLAR FLARE EFFECTS (Sfe): JUNE 1992 Observatory of Sfe Con- Sense & Amplitude fir- Day Began Max. Ended med. H(nT) D(nT) Z(nT) PORT MORESBY Nil sfe's reported GNANGARA Nil sfe's reported CANBERRA Nil sfe's reported 12

13 AUSTRALIAN GEOMAGNETISM REPORT VOLUME 40 No.6 JUNE 1992 INt. J