The Logistic Requirements for Wave Field Measurement Prof. Dr.-Ing. Chia Chuen Kao Director, Coastal Ocean Monitoring Center, National Cheng Kung University

The Logistic RequirementsThe Logistic Requirementsforfor

Wave Field MeasurementWave Field Measurement

Prof. Dr.-Ing. Prof. Dr.-Ing. Chia Chuen KaoChia Chuen KaoDirector, Coastal Ocean Monitoring Center, National Cheng Kung UniversityDirector, Coastal Ocean Monitoring Center, National Cheng Kung University

Dr. Dr. Laurence Zsu-Hsin ChuangLaurence Zsu-Hsin ChuangDeputy Director, Coastal Ocean Monitoring Center, National Cheng Kung UniversityDeputy Director, Coastal Ocean Monitoring Center, National Cheng Kung University

Dr. Dr. Beng-Chun LeeBeng-Chun LeeDirector, Marine Meteorology Center, Central Weather BureauDirector, Marine Meteorology Center, Central Weather Bureau

Coastal Ocean Monitoring Center / NCKU

Purposes of Wave Observation

for the calibration and validation of wave models

for the determination of local wave climate

for the scientific research of marine phenomena

provide "real time" data for the port operations, engineering

constructions and disaster prevention, etc.

provide “Ground Truth” for the calibration of satellite data


Wave Measurements in the Field

In-situ methods– pressure sensor– resistance gauge– two-axis current meter– acoustic gauge– data buoy

Remote sensing techniques– nautical radar– altimeter– Synthetic Aperture Radar (SAR)– scatterometer

provide an extensive set of ocean surface data and will be the trend of wave measurement in the future.


The selection of tools depends on the

– Purposes

real-time / archives data

– Budget affordability

– Observation duration

research / operational

– Environment adjustability

water depth / wave / wind / current


In-Situ Methods

Features of Data Buoy Features of Pile station

- Applied to various water depth (site selection more flexible)

- Robust and Reliable against ship collision- Valid for shallow water region

- Flexible for payload arrangement

- Powered by solar energy (suitable for long-term operation)

- Data transmission via radio telemetry or satellite (provide real time data)


Operational Ocean Monitoring System

Coastal Hydrological Monitoring Network around Taiwan includes

– pile stations

– data buoys

– tidal stations

– coastal meteorological stations

The systems applied to the Network are fully designed, developed, and constructed by COMC.

Data Buoy is the main equipment for offshore measurement


Data Transmission System

Data are transmitted real-time by :

— UHF radio telemetry

— Satellite telecommunication


Data Quality Control (QC) System

" It is more risky to utilize erroneous data than none".

COMC data QC system consists of automatic and manual procedures,

– automated data quality methods according to NDBC/NOAA criteria are adopted and revised their local validity.

– Experienced data analysts are responsible for the manual check of data quality.

The Data Quality Control System has been developing, modifying, and operating as a routine work at COMC for some years.


Maintenance System

Experienced team is essential to carry out the maintenance works.

Maintenance and inspection are necessary in regular base due to harsh marine environment.

– In-site inspection – every three months

– Buoy retrieval for buoy hull refurbishment and sensor calibration – each year

Quick response to system malfunction to guarantee the minimum data loss.

– Permitted recover time

shore station - 1 week

offshore station - 2 weeks (depends on sea state)


Oceanographic Database System

COMC database includes : – wind

– wave

– barometric pressure

– air and water temperature

– tide

COMC offers archives data as well as real-time data

COMC is willing to provide technical support for the

international data exchange and associated services

providing the mutual agreement between countries has been

achieved


Concluding Remarks

To provide long-term and high-quality data, an in-situ operational ocean monitoring system should adequately integrate – structures– mooring– sensors– data acquisition and control – data processing and analysis– data transmission– power– auxiliary sub-systems

The most important logistic requirement for wave measurement is an experienced and disciplinary team

COMC is willing to offer technical services for meteorological and oceanographic measurement in the Far East region


Data Buoy and Pile Station

Measuring items

– Wave

– Wind

– Barometric pressure

– Air temperature

– Water temperature

– Tide

– Current

– Water quality (if needed)

For long-term operational measurement - data buoy, pile station


Location of Data Buoys (by 2003)

105 110 115 120 125 130 135Longitud e

5

10

15

20

25

30

35

Latit

ude

105 110 115 120 125 130 135

15

20

25

30

35

C H IN A

TAIW AN

J AP AN

P hi lipp ineSouth China Sea

(Spratly Is.)

Vietnam

Malaysia


Sketch of COMC Data Buoy

COMC buoy has proven its reliability and survival ability in the harsh environment especially in typhoons.


Significant Wave Height During Typhoon AMBER

24-Aug 25-Aug 26-Aug 27-Aug 28-Aug 29-Aug 30-Aug 31-Aug

D ate

0

2 0 0

4 0 0

6 0 0

8 0 0

sign

ifica

nt w

ave

high

t (cm

)

Hw alien Buoy

Hsinchu Buoy

Taichung p ile station

Kuokwang platform

AMBER, 24~31 Aug, 1997

Hs=1194 cm


Data Flow of Monitoring System


Nan-Sha Wave Observation

Location (10o21’00” N,14o22’05” E)

at the offshore area of the T'ai-

P'ing Tao (Itu-Aba Island) in the

NAN-SHA CH'ÜN-TAO (Spratly Isla

nds), South China Sea

Deployed in April 1999

Operated by COMC

Data transmission

through Inmarsat


Significant wave height Observed by Nan-Sha Buoy

D ate (in 1999)

0

400

sign

ifica

nt w

ave

heig

ht (

cm)

15 , April 1 , Ju ly

Hs = 382 cm

Typhoon KATE

Nan-Sha Buoyin South China Sea

Tropica l C yclonenear the location of buoy

Documents

The Logistic Requirements for Wave Field Measurement Prof. Dr.-Ing. Chia Chuen Kao Director, Coastal Ocean Monitoring Center, National Cheng Kung University