Activities of NICT space weather and ionospheric research

Takuya Tsugawatsugawa@nict.go.jp

Senior ResearcherSpace Weather and Environment Informatics Laboratory

Applied Electromagnetic Research InstituteNational Institute of Information and Communications Technology (NICT)

4-2-1 Nukui-kita, Koganei 184-8795 JAPAN

• The “ONLY National Institute” of Information and Communications technology in Japan

• Staff: permanent researchers: 300, temporal researchers: 400, administrative: 200 (approximately).

• Yearly budget: about 30 billion JPY

• Headquarter: Koganei, Tokyo

• Main Blanches: Keihanna, Kobe, Kashima, Okinawa

• Observatories: Wakkanai, Hiraiso, Yamagawa, Okinawa

About NICT

• Target– Forecasting technology of radio

propagation in the ionosphere– Forecasting technology of

electromagnetic environments on geostationary orbit

Communication troubles

Satellite troubles

NICT space weather activities

• Moreover…– Grasp and mitigation of electromagnetic disaster from NATURAL

source– Especially, suggests appropriate and precise information about

rare and severe events (once in 1000 years) such as ultra-huge frares to decision makers.

– Contribute to Safe and secure use of radio wave

< Time range of forecast >

[X-ray, EUV, light, radio wave]• Approximately 8 min. (light speed)

[ solar energetic particles ]• tens minutes to several hours

[Interplanetary shocks]• approximately 1 hour (from ACE)• two or three days (from the sun)• twenty-seven day (solar rotation)

[solar cycle]• approximately 11 years

Space weather: cause and effect

Ionospheric effects on radio applications

Ionosonde-domestic-SEALION-Antarctica

GPS-TEC DB

Obs.

Open data

Construct of model/simulation code

Experimental: Neural Net for EPB

Numerical：GAIA model

Prior service

4D assimilation

Numerical forecasts

Provide data for contributing to global model(International Reference Ionosphere)

development（automatic scaling/ passive radars）

Provide input data

verification

Meteorological data

Connection of magnetospheric model

Nowcasts and forecasts of ionosphere

Nowcasts and forecasts of ionosphere

Forecast of Ionospheric condition and disturbances

Ne

Tn

Rainfall

Two-dimensional TEC observation using a dense GPS receiver network

TEC perturbations detrended with 10-min window after the 2011 Tohoku EQ. Star mark represents the epicenter. [Tsugawa et al., EPS, 2011]

• A dense GPS receiver network makes it possible to observe two-dimensional TEC variations.

GEONET consisting of more than 1,200 GPS stations

Absolute TEC ROTI (~10km scale irregularity)

Loss-of-Lock (~100m scale irregularity)

12:20 UT(21:20 JST)

12:40 UT(21:40 JST)

13:00 UT(22:00 JST)

GPS loss of lock caused by plasma bubble

Realtime GPS-TEC observation in Japan

• NICT started realtime (now 10-30 min delay) two-dimensional TEC observation using realtime GEONET data in the collaboration with ENRI, Kyoto-U., and Nagoya-U.

• The database of TEC maps from 1997 are available on the website.

http://seg-web.nict.go.jp/GPS

Global GNSS receiver networks

� As of 2012, we are collecting all the available GNSS receiver data (more than 6,000 receivers) which belong to GEONET, UNAVCO, SOPAC, IGS, CORS, EPN, etc (more than 20 providers).

� We have developed regional/global high-resolution maps of absolute TEC, detrended TEC, ROTI, loss-of-lock on GPS signals.

Present

Southeast Asian GNSS NetworksAvailable for Ionospheric Researches

Near Future Image

• Dense and wide-coverage GPS receiver network can reveal their spatial structures, propagation directions, and temporal evolutions.

• The GPS-TEC maps greatly contribute to the ionospheric researches and the nowcast/forecast of space weather.

• However, it is difficult to collect or share the GNSS data in some countries due to government or institute data policy.

EIA?

TID?

EIA?

TID?

Plasma Bubble?

EAI

TID

EAI

TID

Plasma Bubble

GPS Observation Data（（（（RINEX format））））

Header Part

1 epoch

year, month, day, hour, min, sec, flag, # of PRNs, PRNs

Filename: ssssdddh.yyossss: marker nameddd: day of the yearh: file sequence numberyy: 2-digit year

General GNSS-TEC data (ex. IONEX)

Multiple GPS Receivers

RINEX Observation Data

Absolute VTEC Map Data

Input

Output

RINEX Navigation

Data

Satellite Biases

Satellite/receiver biases, absolute slant TEC estimation

Slant-to-vertical TEC conversion

Receiver Biases

• Vertical absolute TEC (VTEC) map data and instrumental biases ofsatellite and receiver are simultaneously derived from the data of multiple GPS receivers and satellite orbit.

• Temporal and spatial resolution of VTEC Map data are too low to observe small-scale ionospheric disturbances such as plasma bubble and ionospheric waves.

An example of IGS TEC map with spatial resolution of 5° in longitude, 2.5° in latitude and temporal resolution of 2 hours (Hernández-Pajares, 2009).Share

IONEX format (v1.0)

Header Part

VTEC values for longitude bins at a latitude bin

epoch start

Filename: cccedddh.yyIccc: Analysis Center designatore: extension or region codeddd: day of the yearh: file sequence numberyy: 2-digit yearI: file type

Proposed GNSS-TEC data for data sharing

Single GPS Receiver

RINEX Observation Data

Input Output

Slant TEC with Biases

Slant-to-vertical TEC conversion

Multiple receiver data processing

Slant TEC derivation

Combined satellite and receiver biases estimation

Combined Biases

Biases subtraction

IGS Orbit Data

Absolute Slant TEC

High-pass filterSlant-to-vertical TEC

conversionMultiple receiver

data processing

VTEC perturbation Map Data

IGS Orbit Data

Absolute VTEC Map Data

• Slant TEC data including satellite and receiver biases are derived from GPS data of one receiver.

• VTEC maps can be derived using the slant TEC data from multi GPS receivers.

• The VTEC data can have high temporal and spatial resolution.

• The Slant TEC data would be suitable for data sharing in the Southeast Asia.

Share

GNSS-TEC exchange (GTEX) format (v0.1)

Header Part

1 epoch

year, month, day, hour, min, sec, flag, # of PRNs, PRNs

Filename: ssssdddh.yy_TECssss: marker nameddd: day of the yearh: file sequence numberyy: 2-digit year

sTEC from PRN 21, TEC flagsTEC from PRN 9, TEC flagsTEC from PRN 18, TEC flagsTEC from PRN 15, TEC flagsTEC from PRN 28, TEC flagsTEC from PRN 5, TEC flagsTEC from PRN 27, TEC flagsTEC from PRN 8, TEC flagsTEC from PRN 26, TEC flag

RINEX files used to derive sTEC

Rec. Position in Lat, Lon, Alt

GNSS-TEC exchange (GTEX) format (v0.2)

Header Part

1 epoch

year, month, day, hour, min, sec, flag, # of PRNs, PRNs

Filename: ssssdddh.yy_TECssss: marker nameddd: day of the yearh: file sequence numberyy: 2-digit year

sTEC from PRN 21, TEC flagsTEC from PRN 9, TEC flagsTEC from PRN 18, TEC flagsTEC from PRN 15, TEC flagsTEC from PRN 28, TEC flagsTEC from PRN 5, TEC flagsTEC from PRN 27, TEC flagsTEC from PRN 8, TEC flagsTEC from PRN 26, TEC flag

• This version is presented in the ISTF/2.

RINEX files used to derive sTEC

Rec. Position in Lat, Lon, AltTypes of obs. in RINEX

Interval according to RINEX

GNSS-TEC data sharing based on GTEX• NICT have developed the database of

“GTEX” data for more than 6,000 GNSS receivers in the world. These data are available via the NICT science cloud, OneSpaceNet (OSN).

• Since the 1st AOSWA workshop held in Chiang Mai, Thailand in February 2012, we are now developing the GTEX data of Thailand, Indonesia, South Korea, and China collaborated with KMITL, LAPAN, KMA, and CMA, respectively.

• We can provide software products to convert RINEX data to GTEX data (Fortran 77) , and to make high-resolution TEC grid data (Fortran 77) and map images (IDL).

• NICT recently released a Windows software “RNX2GTEX” which are available via the NICT website.

Detrended TEC over Thailand. [Courtesy of K. Watthanasangmechai (KMITL)]

Detrended TEC over Indonesia by SUGAR network.

http://seg-web.nict.go.jp/e-sw/download/index_e.html

• Objective: make a regional linkage of information of space weather for operations and researches

• GTEX data sharing is one of important items.

Asia-Oceania Space Weather Alliance: AOSWA

The 1st AOSWA workshop at Chiang Mai, Thailand during 22-24 February 2012. - 10 countries, 30 organizations, 76 participants- 41 oral presentations, 21 poster presentations, 1 tutorial lecture- an excursion- business meeting

http://aoswa.nict.go.jp

IPS Radio and Space Services

(Sydney, Australia)

NOAA/SWPC

(Boulder , U.S.A.)

Natural Resource Canada

(Ottawa, Canada)

NICT (Tokyo, Japan)

Beijing Astronomical Observatory (Beijing China)

National Physical Laboratory

(New Deli, India)

Hydrometeorological Service

(Moscow, Russia)

Space Research Center

(Warsaw, Poland)

Institute of Atmospheric Physics

(Plague, Czech)

Royal Observatory of Belgium

(Brussels, Belgium)

Lund Space Weather Center

(Lund , Sweden)

Space Weather Regional Warning Centers ofInternational Space Environment Service (ISES)

Hermanus Geomagnetic Observatory

(Herumanus, South Africa)

INPE (Sao Jose dos Campos, Brazil)

RRA (Korea)

Space Weather Workshop @USA

Space Weather Week @Europe

AOSWA @Asia-Oceania region

AOSWA meetings

22

Associates (so far)http://aoswa.nict.go.jp/associates.html

AOSWA mailing list <AOSWA@ml.nict.go.jp>

Join Us!Join Us!

Summary• Activities of NICT space weather and ionospheric researches were briefly

introduced.

• High-resolution two-dimensional TEC observations with dense GNSS receiver networks have been used for monitoring and researching severe ionospheric disturbances which can degrade GNSS navigations and cause loss-of-lock on GNSS signals.

• The dense GNSS receiver networks in the Asia-Oceania region would be a powerful tool for the nowcast/forecast of ionospheric disturbances such as plasma bubbles.

• We have developed GNSS-TEC data sharing system based on “GTEX”format under AOSWA (and hopefully under ICAO/ISTF). The GTEX database are available via NICT science cloud “OneSpaceNet”

AcknowledgementGNSS receiver data are provided by GSI, UNAVCO, IGS, SOPAC, CORS, WCDA, CHAIN, PANGA, KASI, KMA, EPN, BKGE, OLG, IGNE, DUT, ASI, ITACyL, ESEAS, SWEPOS, SATREF, BIGF, TrigNet, Geoscience Australia, IPS, RBMC, SUGAR, DPT, LAPAN, and KMITL.