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IAGA 2010, China Changchun Geomagnetic field measurement and data analysis of the Cheongyang observatory in Korea. Po Gyu Park, Wan-Seop Kim. Korea Research Institute of Standards and Science (KRISS). Sung-Dae Hong, Myeong-Son Yu, Se-Jong Lee.
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IAGA 2010, China Changchun Geomagnetic field measurement and data analysis of the Cheongyang observatory in Korea Po Gyu Park, Wan-Seop Kim Korea Research Institute of Standards and Science (KRISS) Sung-Dae Hong, Myeong-Son Yu, Se-Jong Lee Korea Meteorological Administration Juwan Kim Chonbuk National University
I. Location and purposes • Geomagnetic Observatory in Cheongyang(CYN) : operating by KMA (CYN, 126º 51′ 28″, 36º21′ 56″, 150 m) • To measure geomagnetic field precisely • To study the possibility of forecasting of earthquake activity. • To join INTERMAGNET • CYN consisted of 4 huts is located in a mountainous area
Korea 동해 Cheongyang Cheongyang (CYN)
Cheongyang (CYN) CYN old temple
II. Instrumentsand noise measurements • INTERMAGNET recommendations • 3-axis fluxgate magnetometer(DMI), proton magnetometer (GEM), D/I magnetometer (MinGeo) • Nonmagnetic material used for huts, measurement of magnetic properties for rocks and soil • AC magnetic field noise ( ~1 nT in 60 Hz) • DC magnetic stray field of car effect are measured (Excel car, 0.05 nT in 70 m). • Comparison between Cs-He and proton magnetometer • Absolute measurements (10 months, D=-8º, I=58º)
Rock Magn. Properties Paramagnetic !
Soil Magn. Properties Soft ferromagnetic !
Magnetic effect (car) • Axcell: 0.05 nT ( 70 m ) • Tico: 0.05 nT ( 50 m ) * Iron(1 T) : 1 nT (100 m )
III. D/I measurement -Trained by KIGAM(Dr. Lim) and KAKIOKA(Mr. Minamoto)
IV. Difference of vector and scalar data Vector : orthogonal (3-axis) Scalar : Dead zone
V. Uncertainty (Error?) Parameter associated with the result of a measurement, that characterizes the dispersion of the values that could reasonably be attributed to the measurand (VIM2 :International Vocabulary of Basic and General Terms in Metrology) • ISO Guide, Guide to the Expression of Uncertainty in Measurements(GUM), ISO, 1995. • Guidelines for Evaluating and Expressing the Uncertainty of NIST Measurement Results, NIST Technical Note 1297, NIST, 1993. -Quantifying Uncertainty in Analytical Measurements, EURACHEM, 1995. -DIN 1319-4, Gundlagen der Messtechnik
5 steps in Meas. Uncer. evaluation • Modeling the measurement • Identifying uncertainty components • for each input quantity • Evaluating standard uncertainty • Type A, Type B • Sensitivity coefficient • Combining standard uncertainties • of input quantities • Coverage factor • Expanded uncertainty
Uncertainty budgets table(ex.) Extended Uncertainty : coverage factor(k) x Uc * ( Confidence level 95%, k=2 ) ex) Total intensity : (49598.2 ± 0.1) nT ((Reading-0.5)±0.1) nT
VI. Future work(CYN) - D/I measurement continually • Comparison (Proton and Cs-He Magn.) • Evaluation of uncertainties(MFD, D/I?) • Join in INTERMAGNET in 2011 • Time sync. for 1 s data • Contribution to Geomagnetic society
Purpose of magnetic compass? A propitious site for a grave KRISS
References • V. Ya. Shifrin, Po Gyu Park et al., “Experimental estimation of the accuracy of medern scalar quantum magnetometer…”, Phys. Ear. Plan. Inter. 166(2), pp.147-152(2008). • P. G. park, Y. G. Kim, V. Ya. Shifrin, "Maintenance of Magnetic Flux Density Standards on the Basis of Proton Gyromagnetic Ratio at KRISS" IEEE Trans. Instrum. Meas. 54(2), pp.734-737(2005). • V. Ya. Shifrin, V.N.Khorev, A.Ye.Shilov and P.G.Park, “The long-term stability of an atomic magnetic resonance standard system…’, IEEE Trans. Instrum. Meas. 52(2), pp.433-435(2003). • P. G. Park, Y. G. Kim, V. Ya. Shifrin, and V. N. Khorev, "Precise standard system for low dc magnetic field reproduction", Rev. Sci. Instrum., 73(8), pp.3107-3111(2002). • V. Ya. Shifrin, E. B. Alexandrov, T. I. Chikvadze, V. N. Khorev, Po Gyu Park, “Magnetic flux density standard for geomagnetometer”, Metrologia, 37(3), pp.219-227 (2000). • V. Ya. Shifrin, Po Gyu Park, V. N. Khorev, Chang Ho Choi, C. S. Kim, “A New Low-Field Determination of the Proton Gyromagnetic Ratio in Water”, IEEE Trans. Instrum. Meas. 47(3), pp.638-643(1998). • V. Ya. Shifrin, Po Gyu Park, Cheol Gi Kim, V.N. Khorev, Chang Ho Choi, “Experimental Determination of the Gyromagnetic Ratio of the He-4 Atom in Terms of that of the He-3 Nucleus”, IEEE. Trans. Meas. Instrum IEEE Trans. Instrum. Meas. 46(2), pp. 97-100 (1997).