Secular variation of geomagnetic field in Finland

The Earth's magnetic field is slowly changing on time scales that range from years to millennia. Such changes are referred to as secular variation. Secular variation, like the magnetic field itself, originates in the outer core of the Earth, and is an integral part of the process by which the field is generated. Several different mechanisms are probably involved, resulting in changes on different time scales.

In Finland absolute measurements of the geomagnetic field are regularly made at the Nurmijärvi Geophysical Observatory (lat. 60.50°, lon. 24.65°) operated by the Finnish Meteorological Institute and at the Sodankylä Geophysical Observatory (lat. 67.37°, lon. 26.63°) operated by the University of Oulu. This page displays the secular variation at these two observatories since year 2000.

The secular variation and its speed of change is displayed for the three orthogonal magnetic components (X, Y and Z) and for total field (F), horizontal field (H), declination (D) and inclination (I).

In the figures below a continuous black line marks the monthly average values of all days. Red line marks the monthly average of quietest 5 days. Filled black circles mark the annual averages of all days, and red circles mark the annual averages of quiet days. Black circle with inner white dot denotes a predicted value of the annual average of all days for the current year and red circle the same of quiet days. The predicted value is determined by assuming that the averages of the last months of the current year will follow the same trend as similar months in three previous years. Final values for the current year can be computed only when data for the whole year becomes available.

Nurmijärvi (lat. 60.50°, lon. 24.65°)

Latest data available: 2022 - 10

Magnetic field, since year 2000

X_secularX
Y_secularY
Z_secularZ
F_secularF
H_secularH
D_secularD
I_secularI

Annual change of magnetic field, since year 2000

dX_secularΔX/Δt
dY_secularΔY/Δt
dZ_secularΔZ/Δt
dF_secularΔF/Δt
dH_secularΔH/Δt
dD_secularΔD/Δt
dI_secularΔI/Δt

Click on the figures to get a larger view

NUR MONTHLY AVERAGES, ALL DAYS, LAST 12 MONTHS
YearMonthX (nT)Y (nT)Z (nT)H (nT)D (deg)F (nT)I (deg)
20211114708.22366.250439.214897.39.1452593.273.55
20211214705.52370.750447.914895.49.1652601.073.55
2022114702.52376.550453.014893.39.1852605.373.55
2022214703.32377.550458.714894.39.1952611.073.55
2022314704.22380.250461.014895.69.1952613.673.55
2022414702.52382.650463.314894.39.2052615.473.56
2022514709.62385.850464.214901.89.2152618.473.55
2022614711.62389.750470.714904.49.2352625.473.55
2022714708.82394.950477.814902.59.2552631.773.55
2022814702.52399.050481.514896.99.2752633.673.56
2022914694.92400.750488.114889.79.2852637.973.57
20221014690.12406.850497.114886.09.3052645.573.58
NUR MONTHLY AVERAGES, QUIET DAYS, LAST 12 MONTHS
YearMonthX (nT)Y (nT)Z (nT)H (nT)D (deg)F (nT)I (deg)
20211114712.12364.450441.214900.99.1352596.173.54
20211214710.02369.750445.714899.79.1552600.173.54
2022114710.42372.250451.314900.49.1652605.773.55
2022214707.32376.150459.114898.09.1852612.573.55
2022314708.42378.350458.614899.49.1952612.473.55
2022414706.22382.550463.114897.99.2052616.373.55
2022514712.02384.250464.814903.99.2152619.673.55
2022614710.12388.050469.014902.79.2252623.373.55
2022714710.92393.550478.314904.39.2452632.773.55
2022814705.02398.850480.714899.49.2652633.673.56
2022914698.62399.550488.714893.29.2752639.573.56
20221014695.02404.450494.814890.49.2952644.673.57
NUR ANNUAL AVERAGES, ALL DAYS
EpochX (nT)Y (nT)Z (nT)H (nT)D (deg)F (nT)I (deg)
2001.514895.11570.849550.314977.76.0251764.573.18
2002.514895.21600.649593.914980.96.1351807.273.19
2003.514886.31635.749642.914975.96.2751852.673.21
2004.514888.21663.149677.114980.86.3751886.873.22
2005.514885.21691.049712.914981.06.4851921.173.23
2006.514885.41719.349740.114984.36.5951948.173.23
2007.514884.41750.649774.414987.06.7151981.773.24
2008.514882.41784.449808.314989.06.8452014.873.25
2009.514879.31821.049838.814990.36.9852044.373.26
2010.514866.81862.949875.514983.07.1452077.573.28
2011.514853.01905.249915.714974.77.3152113.573.30
2012.514840.71950.049955.814968.27.4952150.073.32
2013.514833.11992.349989.914966.47.6552182.273.33
2014.514824.72031.850025.514963.37.8052215.473.35
2015.514807.42074.650074.314952.17.9852259.073.37
2016.514798.52118.750116.614949.48.1552298.773.39
2017.514782.92167.350170.414941.08.3452347.973.42
2018.514770.92215.850227.214936.28.5352401.073.44
2019.514755.12263.150289.514927.78.7252458.273.47
2020.514738.52306.650350.014917.98.8952513.573.50
2021.514719.72349.150413.314906.09.0752570.873.53
2022.5*14701.12393.150477.214894.69.2552628.973.56

*Predicted values

NUR ANNUAL AVERAGES, QUIET DAYS
EpochX (nT)Y (nT)Z (nT)H (nT)D (deg)F (nT)I (deg)
2001.514900.41569.249548.614982.86.0151764.373.18
2002.514900.71598.649592.914986.26.1251807.773.19
2003.514895.21632.449644.114984.46.2551856.273.20
2004.514894.01660.349677.414986.26.3651888.773.21
2005.514889.51689.249713.514985.16.4751922.873.23
2006.514888.41718.249740.314987.36.5851949.273.23
2007.514886.31749.349774.914988.86.7051982.873.24
2008.514884.91783.249808.314991.36.8352015.573.25
2009.514880.41820.449838.414991.46.9752044.373.26
2010.514869.41861.849876.414985.57.1452079.073.28
2011.514855.91904.649915.914977.57.3152114.673.30
2012.514844.01949.149955.614971.47.4852150.873.32
2013.514836.81991.449989.414969.87.6452182.773.33
2014.514827.42030.750024.614965.87.8052215.273.34
2015.514813.22072.350073.514957.57.9652259.773.37
2016.514802.62117.350116.714953.38.1452299.973.39
2017.514786.72165.850171.214944.58.3352349.773.41
2018.514773.82214.550227.414938.98.5252401.973.44
2019.514757.42262.350289.814929.88.7252459.173.47
2020.514741.12305.450349.714920.38.8952513.873.49
2021.514722.42348.350413.714908.59.0652571.973.53
2022.5*14704.62391.450476.414897.89.2452629.073.56

*Predicted values

NUR SECULAR CHANGE, ALL DAYS
EpochdX/dt
(nT/year)
dY/dt
(nT/year)
dZ/dt
(nT/year)
dH/dt
(nT/year)
dD/dt
(deg/year)
dF/dt
(nT/year)
dI/dt
(deg/year)
2001.01.728.538.44.60.1138.10.01
2002.00.129.843.63.30.1142.70.01
2003.0-8.935.149.0-5.10.1445.50.02
2004.02.027.434.25.00.1034.20.01
2005.0-3.027.935.80.20.1134.40.01
2006.00.128.227.23.30.1127.00.01
2007.0-1.031.334.32.60.1233.60.01
2008.0-2.033.833.92.00.1333.10.01
2009.0-3.136.630.41.30.1429.50.01
2010.0-12.541.936.8-7.30.1733.10.02
2011.0-13.742.340.1-8.30.1736.00.02
2012.0-12.444.840.1-6.50.1836.50.02
2013.0-7.542.334.1-1.90.1632.20.01
2014.0-8.539.535.6-3.10.1533.20.01
2015.0-17.242.848.8-11.20.1743.60.03
2016.0-8.944.042.3-2.60.1739.80.02
2017.0-15.648.653.9-8.50.1949.20.03
2018.0-12.048.556.8-4.80.1953.10.02
2019.0-15.847.462.2-8.50.1957.20.03
2020.0-16.643.560.5-9.70.1755.30.03
2021.0-18.842.463.2-11.90.1757.30.03
2022.0*-18.644.164.0-11.30.1858.10.03

*Predicted values

NUR SECULAR CHANGE, QUIET DAYS
EpochdX/dt
(nT/year)
dY/dt
(nT/year)
dZ/dt
(nT/year)
dH/dt
(nT/year)
dD/dt
(deg/year)
dF/dt
(nT/year)
dI/dt
(deg/year)
2001.00.529.139.03.50.1138.40.01
2002.00.329.444.33.40.1143.40.01
2003.0-5.433.851.2-1.80.1348.50.02
2004.0-1.327.933.31.80.1132.40.01
2005.0-4.428.836.0-1.20.1134.20.01
2006.0-1.129.026.92.20.1126.40.01
2007.0-2.131.134.61.50.1233.50.01
2008.0-1.533.933.42.50.1332.70.01
2009.0-4.437.130.10.10.1428.80.01
2010.0-11.041.537.9-5.80.1634.60.02
2011.0-13.542.739.6-8.00.1735.60.02
2012.0-11.944.539.6-6.10.1736.20.02
2013.0-7.242.333.9-1.60.1632.00.01
2014.0-9.439.335.1-4.00.1532.50.02
2015.0-14.141.748.9-8.30.1744.50.02
2016.0-10.644.943.2-4.20.1840.20.02
2017.0-15.948.654.6-8.80.1949.80.03
2018.0-12.948.756.2-5.60.1952.20.02
2019.0-16.547.862.4-9.10.1957.20.03
2020.0-16.243.159.9-9.50.1754.70.03
2021.0-18.742.964.1-11.80.1758.10.03
2022.0*-17.843.162.7-10.80.1757.00.03

*Predicted values

Sodankylä (lat. 67.37°, lon. 26.63°)

Latest data available: 2022 - 10

Magnetic field, since year 2000

X_secularX
Y_secularY
Z_secularZ
F_secularF
H_secularH
D_secularD
I_secularI

Annual change of magnetic field, since year 2000

dX_secularΔX/Δt
dY_secularΔY/Δt
dZ_secularΔZ/Δt
dF_secularΔF/Δt
dH_secularΔH/Δt
dD_secularΔD/Δt
dI_secularΔI/Δt

Click on the figures to get a larger view

SOD MONTHLY AVERAGES, ALL DAYS, LAST 12 MONTHS
YearMonthX (nT)Y (nT)Z (nT)H (nT)D (deg)F (nT)I (deg)
20211111140.32553.251930.511429.112.9153173.377.59
20211211148.82554.851939.911437.812.9153184.477.58
2022111138.92559.651943.511429.212.9453186.077.59
2022211136.42561.351948.711427.112.9553190.777.59
2022311133.32564.951955.111424.912.9753196.477.60
2022411126.92566.651957.911419.112.9953197.977.60
2022511134.82570.551958.411427.713.0053200.277.60
2022611136.22573.651961.211429.713.0153203.477.59
2022711135.42576.551970.611429.613.0353212.677.60
2022811124.92579.951978.311420.113.0653218.177.61
2022911113.62586.251985.211410.513.1053222.877.62
20221011112.12590.151986.511410.013.1253223.977.62
SOD MONTHLY AVERAGES, QUIET DAYS, LAST 12 MONTHS
YearMonthX (nT)Y (nT)Z (nT)H (nT)D (deg)F (nT)I (deg)
20211111150.72550.351938.111438.612.8853182.877.58
20211211152.32553.751939.611440.912.9053184.777.58
2022111151.02555.251946.111440.012.9153190.977.58
2022211145.52560.651956.611435.912.9453200.377.59
2022311140.92563.051953.411431.912.9653196.377.59
2022411140.12567.551960.611432.112.9853203.477.59
2022511143.42568.351961.211435.512.9853204.777.59
2022611140.92572.151961.611434.013.0053204.777.59
2022711145.02575.551974.211438.713.0153218.177.59
2022811133.72580.151976.711428.713.0553218.477.60
2022911125.82584.251983.711422.013.0853223.777.61
20221011127.02587.251988.011423.813.0953228.377.61
SOD ANNUAL AVERAGES, ALL DAYS
EpochX (nT)Y (nT)Z (nT)H (nT)D (deg)F (nT)I (deg)
2001.511462.81790.051066.011601.78.8852367.377.20
2002.511454.91822.351113.211599.09.0452412.777.21
2003.511431.31858.051162.911581.49.2352457.377.25
2004.511433.41883.751195.011587.69.3652490.077.25
2005.511426.21911.051230.611584.99.4952524.277.26
2006.511425.81936.951260.911588.89.6252554.577.26
2007.511419.51967.051295.611587.79.7752588.177.27
2008.511410.81999.051329.111584.69.9452620.277.28
2009.511403.62032.851362.011583.310.1152652.077.29
2010.511380.92072.651399.011568.110.3252684.777.32
2011.511360.42112.351438.611555.210.5352720.577.34
2012.511338.92155.751477.911542.010.7652756.077.36
2013.511325.52196.451511.711536.510.9852787.777.38
2014.511311.42233.351545.211529.811.1752819.077.39
2015.511285.42273.451592.011512.111.3952860.877.42
2016.511266.32315.051629.811501.711.6152895.477.44
2017.511242.92361.051680.111488.111.8652941.677.47
2018.511226.52405.951734.911481.412.1052993.677.49
2019.511205.22451.151792.711470.212.3453047.677.51
2020.511181.42493.451848.411456.112.5753098.977.54
2021.511154.82534.751907.911439.212.8053153.477.57
2022.5*11127.62576.751969.911422.013.0453210.377.60

*Predicted values

SOD ANNUAL AVERAGES, QUIET DAYS
EpochX (nT)Y (nT)Z (nT)H (nT)D (deg)F (nT)I (deg)
2001.511472.51788.451065.211611.08.8652368.677.19
2002.511466.31820.051112.311609.99.0252414.277.20
2003.511454.31852.951164.311603.39.1952463.577.22
2004.511449.01880.051199.011602.49.3352497.277.23
2005.511440.61908.151236.211598.69.4752532.677.24
2006.511434.81934.851264.311597.39.6052559.777.25
2007.511426.41964.951299.211594.19.7652593.177.26
2008.511417.11997.651332.411590.59.9252624.777.28
2009.511405.02032.551363.511584.710.1052653.777.29
2010.511386.52071.351401.211573.410.3152688.077.31
2011.511367.92111.251440.411562.310.5252723.877.33
2012.511348.72153.851479.511551.210.7552759.577.35
2013.511334.52194.851512.311545.010.9652790.277.37
2014.511318.22231.851546.111536.111.1552821.277.38
2015.511298.32271.151591.911524.311.3752863.377.41
2016.511280.42312.651632.111515.011.5952900.677.43
2017.511256.32358.951685.011500.811.8452949.177.46
2018.511234.42404.951737.111488.912.0852997.477.48
2019.511211.02449.951795.211475.612.3353051.377.51
2020.511186.52492.151850.711460.812.5653102.277.54
2021.511162.62533.951910.811446.512.7953157.877.57
2022.5*11137.22575.051971.411431.013.0253213.677.60

*Predicted values

SOD SECULAR CHANGE, ALL DAYS
EpochdX/dt
(nT/year)
dY/dt
(nT/year)
dZ/dt
(nT/year)
dH/dt
(nT/year)
dD/dt
(deg/year)
dF/dt
(nT/year)
dI/dt
(deg/year)
2001.0-4.529.440.30.10.1539.30.01
2002.0-7.932.347.2-2.70.1645.40.01
2003.0-23.635.749.7-17.60.1944.60.03
2004.02.125.732.16.20.1232.60.00
2005.0-7.327.335.7-2.70.1434.20.01
2006.0-0.426.030.23.90.1330.40.00
2007.0-6.230.134.7-1.00.1533.60.01
2008.0-8.732.033.5-3.10.1632.00.01
2009.0-7.333.832.9-1.30.1731.80.01
2010.0-22.739.837.0-15.20.2132.80.03
2011.0-20.539.739.6-12.90.2135.80.02
2012.0-21.643.439.3-13.20.2335.50.02
2013.0-13.340.833.8-5.40.2131.80.01
2014.0-14.136.933.5-6.70.1931.30.02
2015.0-26.140.146.8-17.70.2241.80.03
2016.0-19.141.637.8-10.40.2234.60.02
2017.0-23.446.050.3-13.60.2546.20.03
2018.0-16.444.954.7-6.70.2452.00.02
2019.0-21.345.257.8-11.20.2454.00.03
2020.0-23.842.355.7-14.10.2351.30.03
2021.0-26.641.259.5-16.90.2354.50.03
2022.0*-27.242.062.1-17.20.2456.90.03

*Predicted values

SOD SECULAR CHANGE, QUIET DAYS
EpochdX/dt
(nT/year)
dY/dt
(nT/year)
dZ/dt
(nT/year)
dH/dt
(nT/year)
dD/dt
(deg/year)
dF/dt
(nT/year)
dI/dt
(deg/year)
2001.0-5.330.341.3-0.60.1540.10.01
2002.0-6.131.647.1-1.10.1645.70.01
2003.0-12.032.952.0-6.60.1749.30.02
2004.0-5.327.134.7-0.90.1433.70.01
2005.0-8.528.137.2-3.80.1435.40.01
2006.0-5.826.728.0-1.30.1327.10.01
2007.0-8.430.135.0-3.20.1533.40.01
2008.0-9.332.733.2-3.60.1731.60.01
2009.0-12.134.931.1-5.80.1829.00.01
2010.0-18.538.837.7-11.30.2134.30.02
2011.0-18.739.939.2-11.10.2135.80.02
2012.0-19.242.639.1-11.00.2335.70.02
2013.0-14.241.032.9-6.20.2130.70.01
2014.0-16.337.033.7-8.90.2031.00.02
2015.0-19.939.345.8-11.80.2142.10.02
2016.0-17.941.640.2-9.30.2237.20.02
2017.0-24.146.252.9-14.20.2548.50.03
2018.0-21.946.052.2-11.90.2548.40.02
2019.0-23.445.158.1-13.30.2453.80.03
2020.0-24.542.255.5-14.80.2351.00.03
2021.0-24.041.760.0-14.20.2355.60.03
2022.0*-25.341.160.6-15.50.2355.80.03

*Predicted values

The speed of secular change for all magnetic components varies approximately linearly with latitude in Finland. For latitude φ the speed of change can be computed from the formula:

Change/year = A + B·(φ - 63°)

The coefficients A and B for each magnetic component are listed in the tables below. (For D and I the unit of A is arcmin/year, for other components it is nT/year. For B the unit is arcmin/year/degree for D and I and nt/year/degree for all other components).

Secular change coefficients for the epoch 2022.0
ALL days
 A   B   
X-21.73-1.25
Y43.34-0.31
Z63.31-0.28
H-13.45-0.86
D12.11 0.52
F57.66-0.17
I 1.80 0.00
Secular change coefficients for the epoch 2022.0
QUIET days
 A   B   
X-20.53-1.09
Y42.37-0.29
Z61.94-0.31
H-12.51-0.68
D11.51 0.52
F56.56-0.17
I 1.80 0.00

You may compute the coefficients for given latitude by entering the latitude here (valid for 59° ≤ φ ≤ 71°):

Secular change for latitude °, epoch 2022.0
 dX/dt
(nT/year)
dY/dt
(nT/year)
dZ/dt
(nT/year)
dH/dt
(nT/year)
dD/dt
(deg/year)
dF/dt
(nT/year)
dI/dt
(deg/year)
ALL DAYS-------
QUIET DAYS-------