BRITISH GEOLOGICAL SURVEY King Edward Point Observatory Monthly Magnetic Bulletin
December 2020 20/12/KE
King Edward Point (UK)
Maps © British Antarctic Survey KING EDWARD POINT OBSERVATORY MAGNETIC DATA
1. Introduction http://www.geomag.bgs.ac.uk/data_service/models _compass/home King Edward Point observatory was installed by the British Geological Survey (BGS), with the 3. The Observatory Operation permission of the Government of South Georgia and the South Sandwich Islands (GSGSSI), in 3.1 GDAS collaboration with British Antarctic Survey (BAS), The observatory operates under the control of the and became operational in February 2011. Geomagnetic Data Acquisition System (GDAS), which was developed by BGS staff, installed and This bulletin is published to provide rapid access to became operational in February 2011. The data the provisional geomagnetic observatory results. acquisition software, running on QNX operated The information is freely available for personal, computers, controls the data logging and the academic, educational and non-commercial communications. research or use. Magnetic observatory data are presented as a series of plots of one-minute, hourly There are two sets of sensors used for making and daily values, followed by tabulations of monthly magnetic measurements. A tri-axial linear-core values. The operation of the observatory and fluxgate magnetometer, manufactured by the presentation of data are described in the rest of this Danish Meteorological Institute, is used to measure section. the variations in the horizontal (H) and vertical (Z) components of the field. The third sensor is oriented Enquiries about the data should be addressed to: perpendicular to these, and measures variations, which are proportional to the changes in declination Geomagnetism Team (D). Measurements are made at a rate of 1 Hz. British Geological Survey Lyell Centre, Heriot Watt University Research Avenue South In addition to the fluxgate sensors there is a proton Edinburgh EH9 3LA precession magnetometer (PPM) making Scotland, UK measurements of the absolute total field intensity (F) at a rate of 0.1Hz. Tel: +44 (0) 131 667 1000 E-mail: [email protected] Internet: www.geomag.bgs.ac.uk The raw unfiltered data are retrieved automatically via Internet connections to the BGS office in 2. Position Edinburgh in near real-time. The fluxgate data are filtered to produce one-minute values using a 61- King Edward Point Observatory, one of the point cosine filter and the total field intensity geomagnetic observatories maintained and operated samples are filtered using a 7-point cosine filter. The by the British Geological Survey (BGS), is situated one-minute values provide input for various data on a site adjacent to the Government of South products, available on-line at Georgia and the South Sandwich Islands (GSGSSI) www.geomag.bgs.ac.uk/data_service/home research station at King Edward Point, Cumberland East Bay, South Georgia. The observatory co- 3.2 Absolute Observations ordinates are: The GDAS fluxgate magnetometers accurately measure variations in the components of the Geographic: 54 ’”S 323 ’”E geomagnetic field, but not the absolute magnitudes. Geomagnetic: 46 24’04”S 029 ’”E One set of absolute measurements of the field are Height above mean sea level: 7 m made manually once per month. A fluxgate sensor mounted on a theodolite is used to determine D and The geographical coordinates are measured by a inclination (I); the GDAS PPM measurements, with handheld GPS device, which uses WGS84 as the a site difference correction applied, are used for F. reference coordinate system. The height above MSL The absolute observations are used in conjunction is determined from the best available contour maps. with the GDAS variometer measurements to The geomagnetic co-ordinates are approximations, produce a continuous record of the absolute values calculated using the 13th generation International of the geomagnetic field elements as if they had Geomagnetic Reference Field (IGRF) at epoch been measured at the observatory reference pillar. 2020.5. On-line access to models (including IGRF), charts and navigational data are available at 4. Observatory Results quiet intervals. Plotting the data in this way highlights this recurrence. Diurnal variations are The data presented in the bulletin are in the form of also clear in these plots and the amplitude changes plots and tabulations described in the following throughout the year highlight the seasonal changes. sections. Longer term secular variation is also illustrated.
4.1 Absolute Observations 4.5 Daily and Monthly Mean Values The absolute observation measurements made Daily mean values of D, H, Z and F are plotted during the month are tabulated. Also included are throughout the year. In addition, a table of monthly the corresponding baseline values, which are the mean values of all the geomagnetic elements is differences between the absolute measurements and provided. These values depend on accurate the variometer measurements of D, H and Z (in the specification of the fluxgate sensor baselines. It is sense absolute−variometer). These are also plotted anticipated that these provisional values will not be (markers) along with the derived preliminary daily altered by more than a few nT or tenths of baseline values (line) throughout the year. Daily arcminutes before being made definitive at the end mean differences between the measured absolute F of the year. and the F computed from the baseline corrected H and Z values are plotted in the fourth panel (in the 5. Conditions of Use sense measured−derived). The bottom panel shows the daily mean temperature in the fluxgate The data presented in this bulletin are provided for chamber. personal, academic, educational, non-commercial research or other non-commercial use and are not for 4.2 Summary magnetograms sale or distribution to third parties without written Small-scale magnetograms are plotted which allow permission from BGS. the month's data to be viewed at a glance. They are plotted 16 days to a page and show the one-minute Reproduction of any part of this bulletin should be variations in D, H and Z. The scales are shown on accompanied by the statement: 'Reproduced with the right-hand side of the page. On disturbed days the permission of the British Geological Survey the scales are multiplied by a factor, which is ©NERC. All rights Reserved'. Publications making indicated above the panel for that day. The use of the data should include an acknowledgment variations are centred on the monthly mean value, statement of the form: ‘The results presented in this shown on the left side of the page. paper rely on the data collected at King Edward Point magnetic observatory, South Georgia operated 4.3 Magnetograms by the British Geological Survey in co-operation The daily magnetograms are plotted using one- with the British Antarctic Survey and the minute values of D, H and Z from the fluxgate Government of South Georgia and the South sensors, with any gaps filled using back-up data. The Sandwich Islands (GSGSSI).’ magnetograms are plotted to a variable scale; scale bars are shown to the right of each plot. The absolute Commercial users can contact the geomagnetism level (the monthly mean value) is indicated on the team for information on the range of applications left side of the plots. and services offered. Full contact details are available at www.geomag.bgs.ac.uk/contactus/staff 4.4 Hourly Mean Value Plots Hourly mean values of D, H and Z for the past 12 months are plotted in 27-day segments corresponding to the Bartels solar rotation number. Magnetic disturbances associated with active regions and/or coronal holes on the Sun may recur after 27 days: the same is true for geomagnetically
© NERC 2020. All rights reserved Edinburgh British Geological Survey 2020
KING EDWARD POINT OBSERVATORY
ABSOLUTE OBSERVATIONS
Declination Inclination Total Field Horizontal Intensity Vertical Intensity Site Absolute Day Time Absolute Baseline Time Absolute Absolute Baseline Absolute Baseline Date difference corrected Observer Number (UT) (º) (º) (UT) (º) (nT) (nT) (nT) (nT) (nT) (nT) 06-Dec-20 341 14:27 -7.0586 -7.0450 14:34 -56.0262 12.4 27597.7 15422.0 15997.6 -22886.6 -23199.5 MG 06-Dec-20 341 14:40 -7.0552 -7.0517 14:47 -56.0229 12.4 27598.0 15423.4 15996.9 -22885.9 -23199.9 MG 28-Dec-20 363 13:51 -7.0911 -7.0500 13:58 -56.0504 12.4 27598.1 15412.5 15998.4 -22893.4 -23199.7 MG 28-Dec-20 363 14:04 -7.0490 -7.0533 14:11 -56.0475 12.4 27599.9 15414.7 15999.3 -22894.1 -23199.3 MG
King Edward Point 2020 Declination : Absolute - Variometer (markers) and Baseline Applied (line)
-7.04 5min
Horizontal Intensity : Absolute - Variometer (markers) and Baseline Applied (line)
15998 20nT
Vertical Intensity : Absolute - Variometer (markers) and Baseline Applied (line)
-23199 20nT
Total Intensity : Absolute (Proton F) - Baseline Adjusted Variometer (derived F)
-12.4 20nT
Temperature Inside Variometer Hut
9.1 10 C
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec King Edward Point December 2020 1 2 3 4
o D -7.05 0.50
H 15407
Z -22903
5 6 7 8
D -7.05
H 15407 150 nT
Z -22903
9 10 11 12
D -7.05
H 15407
Z -22903 150 nT
13 14 15 16
D -7.05
H 15407
Z -22903
6 12 18 24 6 12 18 24 6 12 18 24 6 12 18 24 17 18 19 20
o D -7.05 0.50
H 15407
Z -22903
21 22 23 24
D -7.05
H 15407 150 nT
Z -22903
25 26 27 28
D -7.05
H 15407
Z -22903 150 nT
29 30 31 6 12 18 24 UT D -7.05
H 15407
Z -22903
6 12 18 24 6 12 18 24 6 12 18 24 King Edward Point December 2020 Date: 01-12-2020King Edward Point Day number: 336 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24
Date: 02-12-2020 Day number: 337 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 03-12-2020King Edward Point Day number: 338 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 30nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24
Date: 04-12-2020 Day number: 339 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 20nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 05-12-2020King Edward Point Day number: 340 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 20nT
0 3 6 9 12 15 18 21 24
Date: 06-12-2020 Day number: 341 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 20nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 07-12-2020King Edward Point Day number: 342 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 20nT
0 3 6 9 12 15 18 21 24
Date: 08-12-2020 Day number: 343 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 09-12-2020King Edward Point Day number: 344 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 30nT
Vertical Intensity in nT
-22903 20nT
0 3 6 9 12 15 18 21 24
Date: 10-12-2020 Day number: 345 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 50nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 11-12-2020King Edward Point Day number: 346 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24
Date: 12-12-2020 Day number: 347 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 13-12-2020King Edward Point Day number: 348 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 30nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24
Date: 14-12-2020 Day number: 349 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 15-12-2020King Edward Point Day number: 350 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24
Date: 16-12-2020 Day number: 351 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 20nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 17-12-2020King Edward Point Day number: 352 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24
Date: 18-12-2020 Day number: 353 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 19-12-2020King Edward Point Day number: 354 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 30nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24
Date: 20-12-2020 Day number: 355 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 21-12-2020King Edward Point Day number: 356 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 30nT
Vertical Intensity in nT
-22903 20nT
0 3 6 9 12 15 18 21 24
Date: 22-12-2020 Day number: 357 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 30nT
Vertical Intensity in nT
-22903 20nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 23-12-2020King Edward Point Day number: 358 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 30nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24
Date: 24-12-2020 Day number: 359 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 30nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 25-12-2020King Edward Point Day number: 360 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24
Date: 26-12-2020 Day number: 361 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 27-12-2020King Edward Point Day number: 362 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24
Date: 28-12-2020 Day number: 363 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 29-12-2020King Edward Point Day number: 364 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24
Date: 30-12-2020 Day number: 365 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 31-12-2020King Edward Point Day number: 366 Declination in degrees east
-7.05 15min
Horizontal Intensity in nT
15407 20nT
Vertical Intensity in nT
-22903 10nT
0 3 6 9 12 15 18 21 24 King Edward Point Observatory: Declination (degrees)
-6.95 Rotn
-7.18 2542 Jan20
2543 Feb
2544
2545 Mar
2546 Apr
2547 May
2548 Jun
2549 Jul
2550 Aug
2551 Sep
2552 Oct
2553
2554 Nov
2555 Dec
2556
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 Hourly Mean Values Plotted By Bartels Solar Rotation Number King Edward Point Observatory: Horizontal Intensity (nT
15509 Rotn
15337 2542 Jan20
2543 Feb
2544
2545 Mar
2546 Apr
2547 May
2548 Jun
2549 Jul
2550 Aug
2551 Sep
2552 Oct
2553
2554 Nov
2555 Dec
2556
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 Hourly Mean Values Plotted By Bartels Solar Rotation Number King Edward Point Observatory: Vertical Intensity (nT)
-22873 Rotn
-22966 2542 Jan20
2543 Feb
2544
2545 Mar
2546 Apr
2547 May
2548 Jun
2549 Jul
2550 Aug
2551 Sep
2552 Oct
2553
2554 Nov
2555 Dec
2556
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 Hourly Mean Values Plotted By Bartels Solar Rotation Number King Edward Point Observatory 2020 Daily Mean Declination (deg)
-7.07 10min
Daily Mean Horizontal Intensity (nT)
15423 50nT
Daily Mean Vertical Intensity (nT)
-22920 50nT
Daily Mean Total Intensity (nT)
27626 50nT
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Monthly Mean Values for King Edward Point Observatory 2020
Month D H I X Y Z F
January -7° 04.0´ 15454 nT -56° 01.5´ 15337 nT -1901 nT -22933 nT 27654 nT February -7° 04.6´ 15443 nT -56° 02.6´ 15325 nT -1903 nT -22931 nT 27646 nT March -7° 04.4´ 15437 nT -56° 03.1´ 15319 nT -1901 nT -22930 nT 27642 nT April -7° 04.4´ 15427 nT -56° 04.1´ 15310 nT -1900 nT -22930 nT 27636 nT May -7° 04.2´ 15430 nT -56° 03.3´ 15313 nT -1899 nT -22924 nT 27633 nT June -7° 04.2´ 15427 nT -56° 03.4´ 15309 nT -1899 nT -22920 nT 27628 nT July -7° 04.2´ 15420 nT -56° 04.0´ 15303 nT -1898 nT -22918 nT 27623 nT August -7° 04.1´ 15415 nT -56° 04.3´ 15298 nT -1897 nT -22916 nT 27618 nT September -7° 03.0´ 15407 nT -56° 05.0´ 15291 nT -1891 nT -22914 nT 27612 nT October -7° 03.2´ 15405 nT -56° 05.0´ 15289 nT -1892 nT -22912 nT 27609 nT November -7° 03.3´ 15405 nT -56° 04.7´ 15288 nT -1892 nT -22907 nT 27605 nT December -7° 03.2´ 15407 nT -56° 04.2´ 15291 nT -1892 nT -22903 nT 27603 nT
Note i. The values shown here are provisional.