application of realtime geomagnetic field data at world data center for geomagnetism, kyoto nosé,...

Application of realtime geomagnetic field data at World Data Center for Geomagnetism, Kyoto

Nosé, M., T. Iyemori, H. Toh, and M. Takeda

能勢正仁

World Data Center for Geomagnetism, Kyoto

Graduate School of Science, Kyoto University

京都大学理学研究科・地磁気世界資料センター

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WDC for Geomagnetism, Kyoto

During the 1957-1958 International Geophysical Year (IGY), ICSU created several World Data Centers (WDCs) that were designed to collect, catalog, archive and distribute geophysical and solar data sets.

WDC-C2 for Geomagnetism, the former of WDC for Geomagnetism, Kyoto was established at Kyoto University in 1957.

Type of geomagnetic field data Data Book Magnetogram (normal-run, rapid-run) Digital data (1-hour, 1-minute, 1-second)

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Analog data

From Analog Data to Digital Data

In 1957-1958, the number of observations was drastically increased. Data were in analog format.

After IGY, number of observations decreased temporarily. Until the end of 1970s, analog data is the only available data format. From 1980s, digital data delivery becomes popular gradually. In 1992, number of digital data providers dominates that of analog data

providers. Recently, almost all of observatories deliver data in digital format.

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Number of observatory sending data to WDC-KyotoNumber of observatory sending data to WDC-Kyoto

Collection of Digital Data in Realtime

1993: 1-minute realtime data collection started. 1995: WWW page was opened. 1996: Quicklook magnetograms became available from WWW page. 2004: 1-second realtime data became available from WWW.

1-minute realtime data from ~30 observatories ∙∙∙ ¼ of all observatories 1-second realtime data from 6 observatories

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1-minute realtime 1-minute realtime data collectiondata collection

WWW page WWW page openedopened

Number of observatory sending digital data to WDC-KyotoNumber of observatory sending digital data to WDC-Kyoto

Realtime Realtime magnetogrammagnetogram

Application of Realtime Data in WDC-Kyoto

Collected realtime data are mainly used in the following 3 products.

1. Display of geomagnetic field variations in realtime (i.e., Display of realtime magnetograms),

2. Derivation of the realtime Dst and AE indices, and

3. Realtime detection of a specific phenomenon related to substorms.

4. Future perspective of realtime data

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(1) Realtime Magnetograms

Collection of Realtime 1-minute Data

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Collection of Realtime 1-minute Data over Internet (e-mail, sftp)

E-mail ··∙ over 20 observatories No authentication is needed from a point of view of observatories.

(Access table for SMTP client should be prepared.) In case of undelivery, SMTP client retries to send data. “[email protected]” gives a direct/quick data transfer.

sftp/ftp ··∙ 5 observatories

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Collection of Realtime 1-minute Data by GMS Satellite

Realtime data are collected via the GMS (Geosynchronous Meteorological Satellite) satellite from a few stations. In the past 10 years, ~10 stations were using the GMS satellite. Difficulty in maintainance

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Collection of Realtime 1-second Data

Recent advances in computing and networking have made it possible to collect 1-second data in realtime. Internet (sftp) ISDN Commercial

satellite link

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Tbilisi

Alibag

Phimai

Aso

Shigaraki

Iznik

Urumqi

InchuanKashi

●: RT transfer Operating

●: RT transfer Planned

●: RT transfer Operating

●: RT transfer Planned

Mineyama

ISDN at Mineyama Observatory

100 km north of Kyoto University Located in isolated place and mountains. No optical fiber is available.

By using ISDN, 1-second data are transferred to Kyoto. 64 kbps, ~$30/month Data transfer every 10 min

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Mineyama

Kyoto University

50 km

Commercial Satellite Link at Phimai Observatory

~250 km northeast of Bangkok Located in isolated place and wide fields.

By using iPStar (commercial satellite link), 1-second data are transferred to Kyoto. Upload 1Mbps, Download 0.5Mbps, ~$100/month Data transfer every 20 min

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Number of Accesses

The number of accesses to the 1-min realtime magnetogram becomes ~200,000/month (~7,000/day).

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Realtime MagnetogramRealtime Magnetogram

Service at new Service at new WWW server WWW server started.started.

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(2) Realtime Dst and AE Indices

Derivation of Realtime Dst Index

Dst index was proposed by Sugiura [1964]. A measure of the magnitude of the current which produces the symmetric

disturbance field. Realtime derivation started in 1996.

KAK Japan Meteorological Agency sftp, ~5 min delay

HON, SJG US Geological Survey e-mail, ~12 min delay

HER Hermanus Magnetic Observatory sftp, ~60 min delay

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Realtime Dst Index for July-September 2010

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Derivation of Realtime AE Index

AE index was proposed by Davis and Sugiura [1966]. A measure of global electrojet activity in the auroral zone. Realtime derivation started in 1996.

BRW, CMO US Geological Survey e-mail, ~12 min delay

YKC, FCC, PBQ(SNK) Geological Survey of Canada e-mail, ~5 min delay

NAQ Danish Meteorological Institute e-mail, ~10 min delay

LRV University of Iceland sftp, ~60 min delay

ABK Geological Survey of Sweden e-mail, ~60 min delay

DIK, CCS, TIK, PBK Arctic and Antarctic Research Institute e-mail, GMS, ~12 min delay 17

Realtime AE Index for September 2010

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Number of Accesses

The number of accesses AE index:

~50,000/month. Dst index:

~250,000/month

Realtime magnetogram: ~200,000/month

Realtime data are highly required by users.

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AE indexAE index

Dst indexDst index

New WWW server New WWW server becomes becomes available.available.

User Requirements for Realtime Data and Realtime Dst/AE Indices

Realtime data are required from the following 3 reasons.

1. To compare with realtime data from recent satellite missions or ground observations. THEMIS satellite mission, TWINS satellite mission Ionospheric observations

2. To input to numerical simulation and to compare with calculation results. Fok et al. [2007, JGR] ・・・ Input to radiation belt model (AE index, Dst

index) Kitamura et al. [2008, JGR] ・・・ Comparison with results by realtime

global MHD simulation (AE index)

3. To input to empirical model. K. Tobiska ・・・ Input to Jacchia-Bowman thermospheric density model

(JB2008) (Dst index) J. Lee ・・・ Aviation System, Input to ionospheric model (Dst index)

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Data from THEMIS and TWINS Missions

Data from recent satellite missions become open to public.

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THEMIS data for 2010/09/19 TWINS data for 2010/09/12









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Input to Numerical Simulation

Numerical simulation of radiation belt by M.-C. Fok Input ∙·· Dst index, Solar wind data Realtime calculation results can be seen at http://mcf.gsfc.nasa.gov.

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Fok et al. [2007]

Inpu

tO

utpu

t +

Obs

erva

tion

Simulation Results

Dst Index

Dst Index

Realtime calculation Result

Compare with MHD Simulation Results

MHD global simulation of mangetosphere by K. Kitamura Input ∙·· Solar wind data From calculation results, the

AE index can be estimated, which is compared with the realtime AE index.

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Kitamura et al. [2007]

AE index (from simulation)

AE index (from observation)









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Summary for Realtime Data Collection

Realtime data at WDC-Kyoto 1-minute realtime data from ~30 observatories 1-second realtime data from 6 observatories

Number of accesses Realtime 1-minute magnetogram: ~200,000/month AE index: ~50,000/month. Dst index: ~250,000/month

Realtime data are highly demanded by users

• To compare with realtime satellite/ground data,

• To input to numerical simulation and to compare with calculation results,

• To input to empirical model.

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(3) Realtime Detection of A Specific Phenomenon Related to Substorms

Realtime Detection of Pi2 Pulsation

Pi2 pulsation is defined as geomagnetic field variations with a period range of 40-150 s and an irregular waveform.

Pi2 pulsations are observed clearly on the nightside. Pi2 pulsations appear in a close connection with substorm onsets.

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Dusk

Dawn

Mid-night

Sun

Around 21MLT

Why We Intend to Detect Pi2 Pulsation?

Pi2 pulsations can provide the following information. Substorm occurrence (Longitude of auroral breakups, Magnitude of substorms, …)

If we monitor geomagnetic field variations and detect Pi2 pulsations, we can obtain information about substorms.

Realtime detection of Pi2 pulsations will be useful for the space weather.

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Wavelet Analysis (1)

We have developed a software to detect Pi2 pulsations automatically by wavelet analysis.

Wavelet analysis is similar to Fourier analysis in that a time series data are decomposed into a set of basis functions, which are mutually orthonormal.

Fourier analysis

Wavelet analysis

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Wavelet Analysis (2)

Examples of the Meyer wavelets . We can discuss phenomena in terms of both frequency ( ) and time ( ).

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Different cases of Different cases of

Automated Detection of Pi2 Pulsations (1)

Left panel is the H component of the geomagnetic field at Kakioka. Right panels show wavelet coefficients for =4-6, which cover Pi2 frequency

range (6.7-25 mHz).

When a Pi2 pulsation appear, wavelet coefficient for =5 becomes large. With adequate thresholds for wavelet coefficients, we can find Pi2

pulsations.

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Automated Detection of Pi2 Pulsations (2)

See the movie to know how Pi2 pulsations are detected by wavelet analysis from real-time geomagnetic field data.

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Real-Time Pi2 Detection System (1)

Pi2 detection program is applied to the realtime geomagnetic field data. Program was installed at Mineyama (Japan), Kakioka (Japan), York (U.K.),

Fürstenfeldbruck (Germany), APL (USA), and Teoloyucan (Mexico) geomagnetic observatories.

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Observatory GMLAT GMLON

Mineyama (MYA) 26.31˚ 204.14˚

Kakioka (KAK) 27.37˚ 208.71˚

York (YOR) 56.12˚ 85.09˚

Fürstenfeldbruck (FUR) 48.39˚ 94.56˚

APL (APL) 49.37˚ 353.87˚

Teoloyucan (TEO) 28.76˚ 330.34˚

Fürstenfeldbruck

Mineyama

Kakioka

York Teoloyucan

APL

Real-Time Pi2 Detection System (2)

Detection results are transferred to Kyoto University, Japan in real-time. Onset time and waveforms of Pi2 pulsation are displayed in realtime on our

WWW site.

http://swdcli40.kugi.kyoto-u.ac.jp/pi2/

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Importance of Realtime 1-second Data

Phenomena studied in space physics have a rather shorter time scale about 1 minute. Pi2 pulsations High-latitude negative bays Storm sudden commencements

Realtime 1-second data are useful to monitor these phenomena.

We developed a system to detect Pi2 pulsations in realtime and to provide result for public viewing. http://swdcli40.kugi.kyoto-u.ac.jp/pi2

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Data Logger

Magnetometer

Workstation Workstation6 Observatories Kyoto University

Pi2 Detection by Wavelet Analysis

Processing Pi2 Information

WWW server

E-mail

Public ViewingWWW

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(4) Future Perspective

Method of Realtime Data Transfer

Transfer from a isolated place No service for xDSL,

FTTx No phone line

Transfer from a isolated place No service for xDSL,

FTTx No phone line

Sometimes, link is unstable.

Sometimes, link is unstable.

It was expensive generally, but becomes affordable.

It was expensive generally, but becomes affordable.

In future, realtime data transfer via satellite will become more popular.

In future, realtime data transfer via satellite will become more popular.

Silkroad Magnetometer Project

Realtime 1-second data will be obtained from the longitudinal network of geomagnetic stations.

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WMQ

YCBKNY

KAK

MMB

TFSIZN

EBR

● Planned■ Magnetometer installed■ Magnetometer installed & Realtime data transfer operating

Maintenance of Observatory

Realtime data transfer = Realtime monitor of observatory

Remote maintenance of observatory (?)

Test of remote control by using VPN (Virtual Private Network) and VNC (Virtual Network Computing).

Data are flowing into the monitor PC automatically.

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ISDN modem

Kyoto UniversityMineyama Observatory

Data Logger PCVPN ClientVNC Server

VPN Server

Monitor PCVPN ClientVNC Client

Internet

VPN

Display of Monitor PCDisplay of Monitor PC

Display of Data Logger PCDisplay of Data Logger PC

Data Transfer from Ocean Bottom Measurement

Geomagnetic field is measured at bottom of the northern Pacific ocean. DART (Deep-ocean Assessment and Reporting of Tsunamis) at NOAA may

give a solution for realtime transfer of ocean bottom geomagnetic field data.

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NWP(41o06’08”N, 159o57’47”E, -5580 m)

More than 1,800 km away from KAK.

The seafloor is as old as 129 Ma.

Summary

WDC for Geomagnetism, Kyoto receives 1-minute realtime data from ~30 observatories and1-second realtime data from 6 observatories.

Collected realtime data are mainly used in the following 3 products.

1. Display of realtime magnetograms,

2. Derivation of the realtime Dst and AE indices, and

3. Automatical detection of Pi2 pulsations.

Realtime data are highly demanded by users

• To compare with realtime satellite/ground data,

• To input to numerical simulation and to compare with calculation results,

• To input to empirical model.

Realtime data are also useful for observers

• To collect data,

• To monitor geomagnetic condition,

• To check observatory condition and to maintain the observatory.42

application of realtime geomagnetic field data at world data center for geomagnetism, kyoto nosé,...

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