BRITISH GEOLOGICAL SURVEY Port Stanley Observatory Monthly Magnetic Bulletin September 2019 19/09/PS
d Jason Islands Caracass Island West Falkland SaundersKeppel Island Islan King George Bay Mount Port Salavador Adam Queen Charlotte Bay Mount Osborne Berkley 700m Sapper Hill Sound 705m Weddell Darwin Stanley Goose Island Choiseul Falkland SoundGreen Sound
Port Stephens
Bay of East Falkland Harbours Eagle Passage Falkland Islands
©Crown copyright; Ordnance Survey PORT STANLEY OBSERVATORY MAGNETIC DATA
1. Introduction The geographical coordinates are measured by a handheld GPS device, which uses WGS84 as the the Port Stanley observatory was installed by the British reference coordinate system. The height above Geological Survey (BGS) with financial support MSL is determined from the best available contour from a consortium of oil companies and became maps. The geomagnetic co-ordinates are operational in February 1994. approximations, calculated using the 12th generation International Geomagnetic Reference This bulletin is published to provide rapid access to Field (IGRF) at epoch 2019.5. On-line access to the provisional geomagnetic observatory results. models (including IGRF), charts and navigational The information is freely available for personal, data are available at academic, educational and non-commercial http://www.geomag.bgs.ac.uk/data_service/models research or use. Magnetic observatory data are _compass/home presented as a series of plots of one-minute, hourly and daily values, followed by tabulations of monthly 3. The Observatory Operation values. The operation of the observatory and presentation of data are described in the rest of this 3.1 GDAS section. The observatory operates under the control of the Geomagnetic Data Acquisition System (GDAS), Enquiries about the data should be addressed to: which was developed by BGS staff, installed and became operational in August 2002. The data Geomagnetism Team acquisition software, running on QNX operated British Geological Survey computers, controls the data logging and the Lyell Centre, Heriot Watt University Research Avenue South communications. Edinburgh EH9 3LA Scotland, UK There are two sets of sensors used for making magnetic measurements. A tri-axial linear-core Tel: +44 (0) 131 667 1000 E-mail: [email protected] fluxgate magnetometer, manufactured by the Internet: www.geomag.bgs.ac.uk Danish Meteorological Institute, is used to measure the variations in the horizontal (H) and vertical (Z) 2. Position components of the field. The third sensor is oriented perpendicular to these, and measures variations, Port Stanley Observatory, one of the geomagnetic which are proportional to the changes in declination observatories maintained and operated by the (D). Measurements are made at a rate of 1 Hz. British Geological Survey (BGS), is situated on a site at Sapper Hill near Port Stanley in the Falkland In addition to the fluxgate sensors there is a proton Islands. In 2013 it was necessary to establish a new precession magnetometer (PPM) making position for the observatory absolute pillar due to measurements of the absolute total field intensity degradation in the quality of absolute observations (F) at a rate of 0.1Hz. caused by anthropogenic noise. Following an overlap period of at least six months, the The raw unfiltered data are retrieved automatically observatory results relate to the new position from 1 via Internet connections to the BGS office in January 2014. Edinburgh in near real-time. The fluxgate data are filtered to produce one-minute values using a 61- Old observatory co-ordinates are (Feb 1994 to Dec point cosine filter and the total field intensity 2013: samples are filtered using a 7-point cosine filter. The Geographic: 51°42’15”S 302°06’24”E one-minute values provide input for various data Height above mean sea level: 135 m products, available on-line at www.geomag.bgs.ac.uk/data_service/home New observatory co-ordinates are (Jan 2014 to present): 3.2 Absolute Observations Geographic: 51°42’18.0”S 302°06’25.2”E The GDAS fluxgate magnetometers accurately Geomagnetic: 42°33’00”S 012°46’12”E measure variations in the components of the Height above mean sea level: 130 m geomagnetic field, but not the absolute magnitudes. Two sets of absolute measurements of the field are made manually twice per month. A fluxgate sensor mounted on a theodolite is used to determine D and 4.4 Hourly Mean Value Plots inclination (I); the GDAS PPM measurements, with Hourly mean values of D, H and Z for the past 12 a site difference correction applied, are used for F. months are plotted in 27-day segments The absolute observations are used in conjunction corresponding to the Bartels solar rotation number. with the GDAS variometer measurements to Magnetic disturbances associated with active produce a continuous record of the absolute values regions and/or coronal holes on the Sun may recur of the geomagnetic field elements as if they had after 27 days: the same is true for been measured at the observatory reference pillar. geomagneticallyuiet intervals. Plotting the data in this way highlights this recurrence. Diurnal 4. Observatory Results variations are also clear in these plots and the amplitude changes throughout the year highlight the The data presented in the bulletin are in the form of seasonal changes. Longer term secular variation is plots and tabulations described in the following also illustrated. sections. 4.5 Daily and Monthly Mean Values 4.1 Absolute Observations Daily mean values of D, H, Z and F are plotted The absolute observation measurements made throughout the year. In addition, a table of monthly during the month are tabulated. Also included are mean values of all the geomagnetic elements is the corresponding baseline values, which are the provided. These values depend on accurate differences between the absolute measurements and specification of the fluxgate sensor baselines. It is the variometer measurements of D, H and Z (in the anticipated that these provisional values will not be sense absolute−variometer). These are also plotted altered by more than a few nT or tenths of (markers) along with the derived preliminary daily arcminutes before being made definitive at the end baseline values (line) throughout the year. Daily of the year. mean differences between the measured absolute F and the F computed from the baseline corrected H 5. Conditions of Use and Z values are plotted in the fourth panel (in the sense measured−derived). The bottom panel shows The data presented in this bulletin are provided for the daily mean temperature in the fluxgate personal, academic, educational, non-commercial chamber. research or other non-commercial use and are not for sale or distribution to third parties without written 4.2 Summary magnetograms permission from BGS. Small-scale magnetograms are plotted which allow the month's data to be viewed at a glance. They are Reproduction of any part of this bulletin should be plotted 16 days to a page and show the one-minute accompanied by the statement: 'Reproduced with variations in D, H and Z. The scales are shown on the permission of the British Geological Survey the right-hand side of the page. On disturbed days ©NERC. All rights Reserved'. Publications making the scales are multiplied by a factor, which is use of the data should include an acknowledgment indicated above the panel for that day. The statement of the form: ‘The results presented in this variations are centred on the monthly mean value, paper rely on the data collected at Port Stanley shown on the left side of the page. magnetic observatory, operated by the British Geological Survey.’ 4.3 Magnetograms The daily magnetograms are plotted using one- Commercial users can contact the geomagnetism minute values of D, H and Z from the fluxgate team for information on the range of applications sensors, with any gaps filled using back-up data. The and services offered. Full contact details are magnetograms are plotted to a variable scale; scale available at www.geomag.bgs.ac.uk/contactus/staff bars are shown to the right of each plot. The absolute level (the monthly mean value) is indicated on the left side of the plots.
© NERC 2019. All rights reserved Edinburgh British Geological Survey 2019
PORT STANLEY 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) 07-Sep-19 250 15:23 2.6292 2.9517 15:30 -50.1400 -9.7 28136.5 18033.1 18112.6 -21598.0 -21673.4 NB 07-Sep-19 250 15:36 2.6417 2.9533 15:43 -50.1350 -9.7 28137.5 18035.6 18113.3 -21597.1 -21672.7 NB 21-Sep-19 264 18:15 2.6842 2.9333 18:22 -50.1750 -9.7 28133.4 18017.9 18111.3 -21606.6 -21674.1 NB 21-Sep-19 264 18:28 2.6884 2.9433 18:35 -50.1692 -9.7 28134.4 18020.8 18112.7 -21605.5 -21673.0 NB
Port Stanley 2019 Declination : Absolute - Variometer (markers) and Baseline Applied (line)
2.95 5min
Horizontal Intensity : Absolute - Variometer (markers) and Baseline Applied (line)
18112 20nT
Vertical Intensity : Absolute - Variometer (markers) and Baseline Applied (line)
-21674 20nT
Total Intensity : Absolute (Proton F) - Baseline Adjusted Variometer (derived F)
9.7 20nT
Temperature Inside Variometer Hut
23.8 20 C
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Falkland Islands September 2019 1 2 3 4
o D 2.65 0.50
H 18032
Z -21606
5 6 7 8
D 2.65
H 18032 150 nT
Z -21606
9 10 11 12
D 2.65
H 18032
Z -21606 150 nT
13 14 15 16
D 2.65
H 18032
Z -21606
6 12 18 24 6 12 18 24 6 12 18 24 6 12 18 24 17 18 19 20
o D 2.65 0.50
H 18032
Z -21606
21 22 23 24
D 2.65
H 18032 150 nT
Z -21606
25 26 27 Scale x 2 28
D 2.65
H 18032
Z -21606 150 nT
29 30 6 12 18 24 6 12 18 24 UT UT D 2.65
H 18032
Z -21606
6 12 18 24 6 12 18 24 Falkland Islands September 2019 Date: 01-09-2019Falkland Islands Day number: 244 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 40nT
Vertical Intensity in nT
-21606 20nT
0 3 6 9 12 15 18 21 24
Date: 02-09-2019 Day number: 245 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 30nT
Vertical Intensity in nT
-21606 30nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 03-09-2019Falkland Islands Day number: 246 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 20nT
Vertical Intensity in nT
-21606 20nT
0 3 6 9 12 15 18 21 24
Date: 04-09-2019 Day number: 247 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 20nT
Vertical Intensity in nT
-21606 10nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 05-09-2019Falkland Islands Day number: 248 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 20nT
Vertical Intensity in nT
-21606 20nT
0 3 6 9 12 15 18 21 24
Date: 06-09-2019 Day number: 249 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 20nT
Vertical Intensity in nT
-21606 10nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 07-09-2019Falkland Islands Day number: 250 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 10nT
Vertical Intensity in nT
-21606 10nT
0 3 6 9 12 15 18 21 24
Date: 08-09-2019 Day number: 251 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 30nT
Vertical Intensity in nT
-21606 10nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 09-09-2019Falkland Islands Day number: 252 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 30nT
Vertical Intensity in nT
-21606 20nT
0 3 6 9 12 15 18 21 24
Date: 10-09-2019 Day number: 253 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 20nT
Vertical Intensity in nT
-21606 20nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 11-09-2019Falkland Islands Day number: 254 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 10nT
Vertical Intensity in nT
-21606 10nT
0 3 6 9 12 15 18 21 24
Date: 12-09-2019 Day number: 255 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 20nT
Vertical Intensity in nT
-21606 10nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 13-09-2019Falkland Islands Day number: 256 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 20nT
Vertical Intensity in nT
-21606 10nT
0 3 6 9 12 15 18 21 24
Date: 14-09-2019 Day number: 257 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 20nT
Vertical Intensity in nT
-21606 10nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 15-09-2019Falkland Islands Day number: 258 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 20nT
Vertical Intensity in nT
-21606 20nT
0 3 6 9 12 15 18 21 24
Date: 16-09-2019 Day number: 259 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 30nT
Vertical Intensity in nT
-21606 20nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 17-09-2019Falkland Islands Day number: 260 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 20nT
Vertical Intensity in nT
-21606 10nT
0 3 6 9 12 15 18 21 24
Date: 18-09-2019 Day number: 261 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 10nT
Vertical Intensity in nT
-21606 10nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 19-09-2019Falkland Islands Day number: 262 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 20nT
Vertical Intensity in nT
-21606 10nT
0 3 6 9 12 15 18 21 24
Date: 20-09-2019 Day number: 263 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 20nT
Vertical Intensity in nT
-21606 10nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 21-09-2019Falkland Islands Day number: 264 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 30nT
Vertical Intensity in nT
-21606 10nT
0 3 6 9 12 15 18 21 24
Date: 22-09-2019 Day number: 265 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 20nT
Vertical Intensity in nT
-21606 10nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 23-09-2019Falkland Islands Day number: 266 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 20nT
Vertical Intensity in nT
-21606 10nT
0 3 6 9 12 15 18 21 24
Date: 24-09-2019 Day number: 267 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 20nT
Vertical Intensity in nT
-21606 20nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 25-09-2019Falkland Islands Day number: 268 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 20nT
Vertical Intensity in nT
-21606 10nT
0 3 6 9 12 15 18 21 24
Date: 26-09-2019 Day number: 269 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 20nT
Vertical Intensity in nT
-21606 10nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 27-09-2019Falkland Islands Day number: 270 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 60nT
Vertical Intensity in nT
-21606 30nT
0 3 6 9 12 15 18 21 24
Date: 28-09-2019 Day number: 271 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 30nT
Vertical Intensity in nT
-21606 30nT
0 3 6 9 12 15 18 21 24 Hour (UT) Date: 29-09-2019Falkland Islands Day number: 272 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 30nT
Vertical Intensity in nT
-21606 20nT
0 3 6 9 12 15 18 21 24
Date: 30-09-2019 Day number: 273 Declination in degrees east
2.65 15min
Horizontal Intensity in nT
18032 30nT
Vertical Intensity in nT
-21606 20nT
0 3 6 9 12 15 18 21 24 Hour (UT) Falkland Islands Observatory: Declination (degrees)
2.79 Rotn
2.57 2525 Oct18
2526
2527 Nov
2528 Dec
2529 Jan19
2530 Feb
2531 Mar
2532 Apr
2533 May
2534 Jun
2535 Jul
2536
2537 Aug
2538 Sep
2539
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 Falkland Islands Observatory: Horizontal Intensity (nT)
18134 Rotn
18006 2525 Oct18
2526
2527 Nov
2528 Dec
2529 Jan19
2530 Feb
2531 Mar
2532 Apr
2533 May
2534 Jun
2535 Jul
2536
2537 Aug
2538 Sep
2539
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 Falkland Islands Observatory: Vertical Intensity (nT)
-21596 Rotn
-21630 2525 Oct18
2526
2527 Nov
2528 Dec
2529 Jan19
2530 Feb
2531 Mar
2532 Apr
2533 May
2534 Jun
2535 Jul
2536
2537 Aug
2538 Sep
2539
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 Falklands Is Observatory 2019 Daily Mean Declination (deg)
2.68 10min
Daily Mean Horizontal Intensity (nT)
18059 100nT
Daily Mean Vertical Intensity (nT)
-21611 50nT
Daily Mean Total Intensity (nT)
28164 75nT
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Monthly Mean Values for Port Stanley Observatory 2019
Month D H I X Y Z F
January 2° 42.5´ 18091 nT -50° 04.3´ 18070 nT 855 nT -21615 nT 28186 nT February 2° 41.9´ 18079 nT -50° 05.4´ 18059 nT 851 nT -21614 nT 28179 nT March 2° 41.2´ 18071 nT -50° 06.1´ 18051 nT 847 nT -21613 nT 28172 nT April 2° 40.9´ 18062 nT -50° 06.9´ 18042 nT 845 nT -21613 nT 28167 nT May 2° 40.5´ 18056 nT -50° 07.4´ 18036 nT 843 nT -21612 nT 28162 nT June 2° 39.9´ 18055 nT -50° 07.4´ 18035 nT 840 nT -21611 nT 28160 nT July 2° 39.6´ 18049 nT -50° 07.7´ 18030 nT 838 nT -21609 nT 28155 nT August 2° 39.4´ 18042 nT -50° 08.3´ 18022 nT 836 nT -21607 nT 28149 nT September 2° 38.8´ 18032 nT -50° 09.1´ 18013 nT 833 nT -21606 nT 28142 nT
Note i. The values shown here are provisional.