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Geomagnetic observatory data from
Huancayo, Peru, to investigate long-term trends in the equatorial electrojet region
Jürgen Matzka1, Claudia Stolle1,2, Tarique Adnan Siddiqui1, Lea Geibel1,3, Oscar Veliz4
1GFZ German Research Centre for Geosciences 2University Potsdam
3Inst. Of Geophysics. And Meteorology, Univ. of Cologne 4Instituto Geofísico del Perú
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Quan%fying solar flux and geomagne%c main field influence on the equatorial thermosphere-‐ionosphere system for %mescales
complementary to satellite missions
A Project funded by the German Research Council through the Priority Programme “DynamicEarth”
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• originates in the Earth’s core, strong dipole plus mul%pole -‐> structured • overall decrease over last centuries-‐> influence on ionospheric conduc%vity • ver%cal at the magne%c poles, horizontal at the magne%c (dip) equator • organises the external magnetospheric and ionospheric current systems
The geomagne?c field
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The geomagne?c field: long term evolu?on of the South Atlan?c Anomaly
• significant change over 70 years (%me scale of geomagne%c observatories) • important for long term inves%ga%ons of the ionospheric current systems
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The geomagne?c field: magne?c field strength (leE) and 10-‐year change (right)
• 10-‐year change can be significant (%me scale of satellite mission)
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Geomagne?c observatories (INTERMAGNET consor?um)
• INTERMAGNET observatories have high quality, only two are directly at the dip equator: Addis Ababa and Huancayo
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Geomagne?c Field changes over 100 years: field strength and loca?on of the dip equator
Figure modified aRer Cnossen and Richmond, 2013
Geomagne%c Observatory Huancayo (code: HUA, ins%tute: IGP, Peru) • Decreasing geomagne%c field strength at HUA and the American sector • Dip equator posi%on stable at HUA and in the Asian and Pacific sector
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Hourly mean values of H at HUA from World Data Centre
• There are significant gaps in the 1960ies, 70ies, 80ies and 90ies.
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1920 1930 1940 1950 1960 1970 1980 1990 2000 2010−5
0
5
10
D [d
egre
e]
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
1
2
3
I [de
gree
]1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
2.4
2.6
2.8
3x 104
H [n
T]
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
100
200
300
F10.
7
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
100
200
300
suns
potn
umbe
rs
black: HMV availalbe, red: current data gaps, green: newly discovered HMV
Data availability for HUA since 1922 and ‘newly found data’ (and F10.7)
• Handwri^en tables fill in the longest gap and cover a solar cycle with low F10.7 max
Digital hourly mean values available from World Data Centre Gap in digital hourly mean values Handwri^en tables of hourly mean values: (World Data Centre Bolder and IGP, Peru)
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What we see:
What we learn:
1920 1930 1940 1950 1960 1970 1980 1990 2000 20102.4
2.6
2.8
3x 104
H [n
T]
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
1
2
3
I [de
gree
]
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
100
200
300
F10.
7
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
100
200
300
suns
potn
umbe
rs
black: HMV availalbe, red: current data gaps, green: newly discovered HMV
b)
c)
d)
a)
20 24
20 24
!
16
Geomagne?c and solar parameters for Huancayo ?me series
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What we see:
Horizontal field strength
What we learn:
Decrease by 19% -‐> conduc%vity
1920 1930 1940 1950 1960 1970 1980 1990 2000 20102.4
2.6
2.8
3x 104
H [n
T]
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
1
2
3
I [de
gree
]
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
100
200
300
F10.
7
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
100
200
300
suns
potn
umbe
rs
black: HMV availalbe, red: current data gaps, green: newly discovered HMV
b)
c)
d)
a)
20 24
20 24
!
16
Geomagne?c and solar parameters for Huancayo ?me series
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What we see:
Inclina%on: 2.26° is 125 km, that gives
What we learn:
< 10% change in the magne%c signal of the EEJ
1920 1930 1940 1950 1960 1970 1980 1990 2000 20102.4
2.6
2.8
3x 104
H [n
T]
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
1
2
3
I [de
gree
]
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
100
200
300
F10.
7
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
100
200
300
suns
potn
umbe
rs
black: HMV availalbe, red: current data gaps, green: newly discovered HMV
b)
c)
d)
a)
20 24
20 24
!
16
Geomagne?c and solar parameters for Huancayo ?me series
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What we see:
F10.7 -‐> conduc%vity
What we learn:
Low solar max cycles 20 and 24
1920 1930 1940 1950 1960 1970 1980 1990 2000 20102.4
2.6
2.8
3x 104
H [n
T]
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
1
2
3
I [de
gree
]
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
100
200
300
F10.
7
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
100
200
300
suns
potn
umbe
rs
black: HMV availalbe, red: current data gaps, green: newly discovered HMV
b)
c)
d)
a)
20 24
20 24
!
16
Geomagne?c and solar parameters for Huancayo ?me series
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What we see:
Sunspot nr. further back than F10.7
What we learn:
Solar cycle 16 also very low
1920 1930 1940 1950 1960 1970 1980 1990 2000 20102.4
2.6
2.8
3x 104
H [n
T]
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
1
2
3
I [de
gree
]
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
100
200
300
F10.
7
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
100
200
300
suns
potn
umbe
rs
black: HMV availalbe, red: current data gaps, green: newly discovered HMV
b)
c)
d)
a)
20 24
20 24
!
16
Geomagne?c and solar parameters for Huancayo ?me series
-
1920 1930 1940 1950 1960 1970 1980 1990 2000 20102.4
2.6
2.8
3x 104
H [n
T]
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
1
2
3
I [de
gree
]
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
100
200
300
F10.
7
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
100
200
300
suns
potn
umbe
rs
black: HMV availalbe, red: current data gaps, green: newly discovered HMV
b)
c)
d)
a)
20 24
20 24
!
16
Comparison with Addis ?me series
Addis Ababa geomagne%c observatory • long term longitudinal comparison
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Newly found microfilm from World Data Centre Boulder
• arriving for digital scanning
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Newly found microfilm from World Data Centre Boulder
• one month: daily rows, columns by the hour, sums, quiet days mean varia%on
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A first test: quiet day mean daily varia?on at HUA for previously missing data
1962J F M A M J J A S O N D
0 to 24 UT for January to December
HUA
mea
n da
ily v
aria
tion
for q
uiet
day
s of
H
1963
J F M A M J J A S O N D
1967
J F M A M J J A S O N D
1968
J F M A M J J A S O N D
1969
J F M A M J J A S O N D
1970
J F M A M J J A S O N D
1971
J F M A M J J A S O N D
1972
J F M A M J J A S O N D
1973
J F M A M J J A S O N D
1974
J F M A M J J A S O N D
1975
J F M A M J J A S O N D
1976
J F M A M J J A S O N D
1977
J F M A M J J A S O N D
1978
J F M A M J J A S O N D
1979
J F M A M J J A S O N D
1980
J F M A M J J A S O N D
For January to December: 0 to 24 UT
1980 1979 1978 1977 1976 1975 1974 1973 1972 1971 1970 1969 1968 1967 1963 1962
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SoEware to retype handwri[en values
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Hourly mean values of H at HUA
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Hourly mean values of H at HUA
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Hourly mean values of H at HUA 1961 to 1985
• 1961 to 1985: Almost completely, last data gaps are currently filled in
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Hourly mean values of H at HUA in October 1963
• Example for day2day-‐variability and Dst-‐effects(?)
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Hourly mean values of H at HUA in October 1963
• The night %me HUA H records follow nicely the Dst-‐index (Kyoto)
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Hourly mean values of H at HUA
• Difference in the World Data Centre (i.e. Winch, 1981) and our data set from May 1st, 1965
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Hourly mean values of H at HUA
• Difference in the World Data Centre (i.e. Winch, 1981) and our data set from August 1966
• such differences can likely be resolved by -‐ analysis of data (seasonal means vs. F10.7, …) -‐ going back to historic opera%onal records
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• We have (almost) digi%sed the ‘newly found’ H-‐component
• Next step: inves%gate homogeneity of the %me series • Next step: inves%ga%ng long term trends due to
changing magne?c main field strength under defined (or corrected for) solar flux condi%ons
• Further opportuni?es: -‐ Long term %dal signal -‐ Lunar %dal signal and Sudden Stratospheric Warming -‐ Day2day-‐variability -‐ … Data will be available at the World Data Centres for Geomagne?sm once also the ver%cal component Z and declina%on D are digi%sed and quality-‐checked.
Conclusion
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Annual Mean Data Viewer: HUANCAYOAs recorded in 2014, mean calculated from all days
Dashed lines show annual means adjusted by jump values
1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010Years from 1922 to 2014
-175.0-150.0-125.0-100.0
-75 .0-50 .0-25 .0
.025.050.075.0
100.0125.0150.0175.0200.0225.0250.0275.0300.0325.0350.0375.0400.0425.0450.0475.0500.0
D, range 638min., mid-point 168min.
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The ionospheric current systems
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What we see:
Horizontal field strength
Inclina%on: 2.26° is 125 km, that gives F10.7 -‐> conduc%vity Sunspot nr. further back than F10.7
What we learn:
Decrease by 19% -‐> conduc%vity
< 10% change in the magne%c signal of the EEJ Low solar max cycles 20 and 24
Solar cycle 16 also very low
1920 1930 1940 1950 1960 1970 1980 1990 2000 20102.4
2.6
2.8
3x 104
H [n
T]
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
1
2
3
I [de
gree
]
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
100
200
300
F10.
7
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
100
200
300
suns
potn
umbe
rs
black: HMV availalbe, red: current data gaps, green: newly discovered HMV
b)
c)
d)
a)
20 24
20 24
!
16
Geomagne?c and solar parameters for Huancayo ?me series
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1
2 3
April 01 to 20, 1976
200300400500600
HM
V [n
T]
-300-200-1000
Dst
[nT]
Observatory: HUA Componenent: H Base: 27.000 nT Year: 1976 Month: April 13h - 14h 14h - 15h 15h - 16h17 (quiet) 482 536 57018 quiet 457 504
typical table ofHuancayo hourlymeanvalues (HMVs):handwritten,microfilmed,scanned image
masks displaying relevantparts of scanned image
mask for manual typing of HMVs
display of HMVs and Dst-index
data
bas
is
con
cept
of m
anua
l dig
itiza
tion
prog
ram
Title
Can check internal consitncy Of typing process