Geomagnetic Charts of Southern Part of Korean Peninsula

as of 2010.0

1

LIM, Mutaek*1, MOON, Jiyoung2, PARK, Youngsue1, SHIN, Younghong1 , RIM, Hyoungrae1

1 : Korea Institute of Geoscience and Mineral Resources (KIGAM)http://www.kigam.re.kr

2 : National Geography Information Institute (NGII)http://www.ngii.go.kr

22th Sep. 2010

Presented at 14th IAGA Workshop at Changchun, China

Contents

Present status of geomag. meas. in south. part of Korea

NGII is to make geomag. charts from measured data

Geomag. charts as of 1990.0 from data meas. 1976 - 1996

Geomag. charts as of 2010.0 from data meas. 1998 - 2008

Geomag. charts as of 2010.0 from data newly meas. 2010

Concluding Remarks

Beijing

Changchun

Location of Geomag. Obs.

Present status of geomag. meas. in south. part of Korea - 1

Present status of geomag. meas. in south. part of Korea - 2

Location of Geomag. Obs.

Name Instru.Dur. of Meas.

Instit. remarks

ZIN (Zinsen = Incheon)

3-axis & scalar

1918 ~ 1944

yearly averaged data exist

ICN(Icheon, not yet applied to IAGA)

3-axis & scalar

1996 ~ continual

RRL RF521B, geom. noise

YON(Yongin, not yet applied to IAGA)

3-axis & scalar

1997 ~ continual RRL RF521B, geom. noise

JEJ(Jeju, not yet applied to IAGA)

3-axis & scalar

1997 ~ continual

RRLRF521B, geom. noise

DZN(Daejeon, not yet applied to IAGA)

3-axis & scalar

1998 ~ continual

KIGAM Flare+, geom. noise

GZU(Gyeongju, not yet applied to IAGA)

3-axis & scalar

2000 ~ continual

KIGAM Flare+, geom. noise

HOS(Hongseong, not yet applied to IAGA)

3-axis & scalar

2002 ~ continual

KIGAM Flare+, geom. noise

CYN(Cheongyang, applied to IAGA ?)

3-axis & scalar

2008 ~ continual

KMAMagRec1B, most free from geom. noise

Summary of Geom. Obs. in Korea

Main & visible purpose for NGII to make geomagnetic charts is the necessity to put the declination on

the geographical maps provided to the people.

NGII has done absolute geomagnetic measurements on repeat stations and/or on random points:

1976 ~ 1996 : on more than 500 random points including repeat stations, total 902 meas.-pt.

1998 ~ 2008 : on only 30 repeat stations, total 74 meas.-pt.

NGII committed to KIGAM to make geomagnetic charts of total magnetic intensity, declination and

inclination as of 1990.0 and as of 2010.0 with the data measured by NGII. This can be

considered to be an additional work to the main work below.

And NGII committed to KIGAM to do absolute geomagnetic measurements on the whole of 30 repeat

stations in the year of 2010, to make geomagnetic charts with the newly measured data, and to

compare the two sets of charts of the year 2010. 0.

The absolute geomagnetic measurements are under doing now. 5

NGII is to make geomag. charts from measured data

Assuming that local distribution of geomagnetic features(tot. mag. intens., dec., inc.) vary very smoothly, and therefore

Considering IGRF as exemplary, many outlying data from the IGRF were eliminated.

The greatest deficiency of the data set being the non-existence of the measurement date and time records, we have imagined that each measurement has been done in the middle of the year. So, there would be considerable errors on geomagnetic features(tot. mag. intens., dec., inc.), especially more on declination than on inclination.

6

Geomag. charts as of 1990.0 from data meas. 1976 – 1996 - 1

7

Geomag. charts as of 1990.0 from data meas. 1976 – 1996 - 2

Original data distribution : 902 meas.-pt.

Reduced data distribution : 773 meas.-pt.

Reduced data distribution : 677 meas.-pt.

Finally reduced data distribution : 593meas.-pt.

Final constraints applied to eliminate the meas.-pt. thought to have considerable deficiency :if abs(tot. mag. intens. – IGRF11) > 500 nT orif abs(dec. – IGRF11) > 0.5 deg orif abs(inc. – IGRF11) > 0.5 deg

Geomag. charts as of 1990.0 from data meas. 1976 – 1996 - 3

Original data distribution of difference of each feature – IGRF11

Finally reduced data distribution of difference of each feature – IGRF11

Constraints applied

Geomag. charts as of 1990.0 from data meas. 1976 – 1996 - 4

Final geomagnetic charts as of 1990.0 in comparison with the IGRF11

Also assuming that local distribution of geomagnetic features(tot. mag. intens., dec., inc.) vary very smoothly, and therefore

Considering IGRF as exemplary, several outlying data from the IGRF were eliminated.

The considerable deficiency of the data set being the non-existence of the measurement time records, we have imagined that each measurement has been done in the middle of the day. So, there would be some errors on geomagnetic features(tot. mag. intens., dec., inc.), especially more on declination than on inclination.

10

Geomag. charts as of 2010.0 from data meas. 1998 – 2008 - 1

11

Geomag. charts as of 2010.0 from data meas. 1998 – 2008 - 2

: measured values for rep. stn. No. 1,

- : values calculated from IGRF11

12

Geomag. charts as of 2010.0 from data meas. 1998 – 2008 - 3

Original data distribution : 74 meas.-pt.

Finally reduced data distribution : 72 meas.-pt.

Final constraints applied to eliminate the meas.-pt. thought to have considerable deficiency :if abs(tot. mag. intens. – IGRF11) > 500 nT orif abs(dec. – IGRF11) > 0.5 deg orif abs(inc. – IGRF11) > 0.5 deg

Geomag. charts as of 2010.0 from data meas. 1998 – 2008 - 4

Original data distribution of difference of each feature – IGRF11

Finally reduced data distribution of difference of each feature – IGRF11

Constraints applied

Geomag. charts as of 2010.0 from data meas. 1998 – 2008 - 5

Final geomagnetic charts as of 2010.0 in comparison with the IGRF11

To ameliorate the quality of geomagnetic charts to be made from newly measured data in 2010, we will add 3 works as follows;

1. to get site difference between each rep. stn. and geomagnetic observatories

2. to do magnetic survey to certify that each rep. stn. is at a place without any magnetic anomaly

3. to do at least 5 sessions of absolute geomagnetic measurements to get a believable baselines

15

Geomag. charts as of 2010.0 from data newly meas. 2010 - 1

16

Geomag. charts as of 2010.0 from data newly meas. 2010 - 2

Set up of a magnetometer

Derived difference -754.5 nT fromBlue : CYN Geomagnetic Obs. Red : GZU Geomagnetic Obs.

to get site difference between each rep. stn. and geomagnetic observatories

17

Geomag. charts as of 2010.0 from data newly meas. 2010 - 3

Magnetic survey Magnetic survey result on rep. stn. no. 22Left : total mag. Intens. (nT)Right : gradient (nT/m)

to do magnetic survey to certify that each rep. stn. is at a place without any magnetic anomaly

18

Geomag. charts as of 2010.0 from data newly meas. 2010 - 4

excel file of 1 measurement

to do at least 5 sessions of absolute geomagnetic measurements to get a believable baselines

Date 2010-09-08-1 　 Observer 임무택 　 Code 1-22-3- 경주 　

　 　 　 　 　 　 　 　 　

　 　 　 　 　 　 　 　 　

Mark Up 209 23 22 209.3894　 F site Diff 0.0 　

Mark Down 29 23 30 29.3917　 　 　 　

Mark Up 209 23 24 209.3900　 　 　 　

Mark Down 29 23 25 29.3903　 　 　 　

Mean 119 23 25 119.3903　 　 　 　

　 　 　 　 　 　 　 　 　

FM True 116 2 35 116.0431　 　 　 　

TN Circle 3 20 50 3.3473　 　 　 　

　 　 　 　 　 　 　 　 　

　 Time 　 　 　 　 Flare D 　 　

ED 16:38:12 355 38 59 355.6497 -388.9　 　

WD 16:40:47 175 33 44 175.5622 -388.5　 　

EU 16:45:11 175 38 31 175.6419 -387.8　 　

WU 16:49:23 355 37 40 355.6278 -387.1　 　

Mean 16:43:23 265 37 13 265.6204 -388.1　 　

Declination (Absolute) -7 43 37 -7.7269　 　 　

　 　 　 　 　 　 　 　 　

　 Time 　 　 　 　 Flare H Flare Z Flare F

SU 17:14:50 128 27 47 51.5369 25.5 1295.7 50173.8

ND 17:17:09 308 29 54 51.5017 25.3 1295.6 50173.7

SD 17:05:11 231 32 45 51.5458 25.9 1295.4 50174.0

NU 17:07:38 51 30 41 51.5114 25.6 1295.5 50173.7

Mean 17:11:12 51 31 26 51.5240 25.6 1295.6 50173.8

Inclination (Absolute) 51 31 26　 　 Corrected 50173.8

　 　 　 　 　 　 　 　 　

　 Flare Absolute Baseline Baseline 　 　 　 　

H 25.6 31217.5 31192.0　 　 　 　 　

D -0.7122 -7.7269 -7.0146 -3809.2557 -7 0 52

Z 1295.6 39279.5 37983.9　 ^ Dec. of Baseline 　

　 　 　 　 　 　 　 　 　

Collimation 시준 ( 오차 ?) 　 　 　 　 　 　 　

Dec. δ -0.014　 　 　 　 　 　 　

Dec. ε -0.015　 　 　 　 　 　 　

Dec. Zo 13.8　 　 　 　 　 　 　

Inc. ε -0.005　 　 　 　 　 　 　

Inc. Zo 15.3　 　 　 　 　 　 　

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Geomag. charts as of 2010.0 from data newly meas. 2010 - 4

Summary of 6 measurements with baselines calculatedQuality?

to do at least 5 sessions of absolute geomagnetic measurements to get a believable baselines

ListDeclinatio

n InclinationCorrected

Total Hbase Dbase Zbase

2010-09-08-1 -7.7269 51.5240 50173.8333 31191.97 -3809.2557 37983.93

2010-09-09-2 -7.7745 51.5855 50141.2000 31155.99 -3827.3676 38004.86

2010-09-09-3 -7.8178 51.5445 50141.1000 31183.58 -3827.9098 37982.78

2010-09-09-4 -7.4476 51.6649 50148.4333 31101.57 -3613.8290 38049.50

2010-09-09-5 -7.8110 51.5753 50156.0333 31160.57 -3817.6686 38004.58

2010-09-09-6 -7.7967 51.5349 50159.1667 31187.10 -3815.8676 37984.32

Concluding remarks

Geomag. charts as of 1990.0 were made from data meas. 1976 – 1996 by eliminating considerable no. of original meas.-pt.

Geomag. charts as of 2010.0 were also made from data meas. 1998 – 2008 by eliminating a little of original meas.-pt.

Geomag. charts as of 2010.0 with an ameliorated quality will be made from data newly meas. 2010 by applying all generally used methods. We will do everything to get a more reasonable result than the olders.

Thank you for your attention!