New River Information Systemand

Radar Rain Gauge Network in Japan

11 May 2005 at Hanoi

Dr. NAKAO, TadahikoFRICS, Japan

Information indispensable for Flood Fighting and Evacuation

© MLIT

Inundation of ToyookaCity, 21 October 2004

New Integrated River Information System

Regional Dev. Bureaus

Regional Bureaus

Prefectures

Municipalities Private EnterprisesMass Media PrefecturesRegional Bureaus

Radar Rain Gauges

Telemeter Stations

Japan Water Agency

JWA

Sharing of Information

PublicJMA

Meteorological Agency

Sources of Data

28,550 128 267 7,513 1,321 976 18,345 Total

12,809 12,809 Average Rainfall (Radar)

967 6 156 805 Average Rainfall (Telemeter)

14,774 128 261 7,357 1,321 976 4,731 Subtotal

1,270 46 100 190 934 Others

5,088 13 67 3,248 1,760 Water Stage

8,390 69 94 3,919 1,321 976 2,011 TM Rain Gauges

26 26 Radar Rain Gauges

TotalOthersJWALocal Gov’tJMAHighway

BureauRiver Bureau

As of 01 March 2005

5 Points of the New System

• National system integrating local systems• Single system integrating telemeter & radar• Single display viewing data from variety of

sources• Single user terminal for both flood and non-flood

tasks in an ordinary office environment• Coherent information to be shared among river

administrators, related organizations, municipalities, and the public

Integration of Telemeter & Radar

Radar Terminal Telemeter Terminal

On-line Calibration&

Real time Validation

Unified Terminal

Single Display for different SourcesRiver Dept. Local Governments

JMA, etc.

River Data Terminal

Data from Local Governments

JMA, etc.Unified Terminal

Integration Procedure• River Information Systems in Japan have been

developed for individual river basins. Minor difference in the application of general rules poses difficulty for integration.

• Integration of data obtained from other agencies than river administration also demands careful handling.

• Establishment and maintenance of a “metadata”database should be paid special attention.

• In solving above problems, eXtensible Markup Language (XML) has shown its effectiveness.

Binary transmission currently used

0 0 0 10 0 1 40 4 f 2e 8 2 00 0 0 05 3 0 b0 0 0 10 0 0 0 0 0 0 00 0 0 00 0 0 0 0 0 0 1

バイナリ形式

0 0 0 10 0 1 40 4 f 2e 8 2 00 0 0 05 3 0 b0 0 0 10 0 0 0 0 0 0 00 0 0 00 0 0 0 0 0 0 1

バイナリ形式

• Kind of data• Calculated/Observed• RiverAreaNumber• (Reserved)• ControlOfficeNumber• StationNumber• (Reserved)• Flag1, Flag2• Flag3, Flag4• Data

Transmission of Data using XML

• More number of bits than binary transmission, but

• More readable therefore more convenient for system maintenance

• Taking advantage of high speed transmission network and computer power

* Data indicated by arrows are provided from (meta)database(s).

*

*

*

Some Views of the New System (1)

View of the New System (2)

Radar Rain Gage

Takasuzuyama Radar, August 1998

雨量強度(mm/h)

Masked AreaMasked AreaDifference between RadarsDifference between Radars

Synthesizing without Calibration

Opposition to the Radar Rain Gauge System

• Seams between radars show that radars will give us a false information.

• A Good moving picture is available, but it is not suitable for further usages.

• A ground rainfall gauge gives the real and reliable data.

• Against these prejudices, FRICS developed an online synthesis system incorporating real-time calibration.

Radar Image Synthesizing Map

MLIT’s 26 radars are synthsized based on accuracy of each radar.

美土里奥津

倉床

郡家

徳島

古高松大崎町役場

久比

東之川

寺川

御三戸

佐敷

Accuracy of the Radar Rainfall System (1)

Evaluation through comparison with ground raingages

雨量時系列(高知工事：佐敷)

0

10

20

30

40

50

60

70

13 14 15 16 17 18 19 20 21 22 23 0 1 2 3 4 5 6 7 8 9 10 11 12

2000年11月1日～2日

雨量(mm/h)

地上雨量 レーダ雨量 レーダ(DWのみ) レーダ(均質化補正・DW)

雨量時系列(気象庁：徳島)

0

5

10

15

20

25

30

7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0 1 2 3 4 5 6

2000年9月11日～12日

雨量(mm/h)

地上雨量 レーダ雨量 レーダ(DWのみ) レーダ(均質化補正・DW)

Ground

Radar (raw)

Radar (processed)

Sashiki Station

Tokushima Station

ComparisonGround & Radar

◎高蔵寺(国)

◎名古屋北(国)◎瀬戸(国)

◎三国山(国)

◎妻木(国)

◎瑞浪(国)

◎山岡(国)

◎論栃(国)

◎日吉(国)

◎恵那(気)

◎春日井(国)

◎多治見(気)

◎名古屋(気)

◎多治見(国)

八田川流域春日井地点

△

雨域の移動方向

ＹStream(20Km2)

Main River

For a Small Tributary without Raingage

Accuracy of Radar evaluated through Runoff (2)

Runoff Calculated from neighboring Ground Gages: Poor Result

0

100

200

300

400

500

600

0 3 6 9 12 15 18 21 0 3 6 9 12 15 18 21 0

(m3/s)0

10

20

30

40

50

60

(mm/10min)

計算流量

実測流量

11日 12日 時

雨　　量

流　　量

Calculated Discharge

Observed Discharge

0

100

200

300

400

500

600

0 3 6 9 12 15 18 21 0 3 6 9 12 15 18 21 0

(m3/s)0

10

20

30

40

50

60

(mm/10min)

計算流量

実測流量

時12日11日

Runoff Calculated from Radar Rain Gauge:Peaks were Simulated Well.

雨

量

流

量

Calculated Discharge

Observed Discharge

Radar Information is Reliable!

• Since the first installation of a radar raingage on the Mt. Akagi, doubts have been raised: Does it give quantitative information, and is it reliable?

• FRICS answers positively to this question.Yes, radar system will prvide quatitative and reliable information vital for river administration.

• However, due consideration should be paid to get optimum results. Thorough tuning and calibration is essential to make best use of the system.

Thank you for listening.

mailto: nakao@river.or.jp

http://www.river.go.jp/http://i.river.go.jp/

Radar Images: