Email: cpy@pop.jaring.my
Fax: +(603) 293 4084
1. Introduction
The Department of Survey and Mapping Malaysia (DSMM) is the main government agency in Malaysia responsible for the acquisition, processing, archiving, and dissemination of sea-level data. To date, there are 12 tidal stations along the coast of Peninsular Malaysia (West Malaysia) and 9 tidal stations along the coast of Sabah and Sarawak (East Malaysia).
Before DSMM took over the responsibility for the tide stations from the State Land and Survey of Sabah in 1984 and from the State Land and Survey of Sarawak in 1990, all the tide stations in the states were held under the responsibility of each State Land and Survey respectively.
This article will describe briefly the history of the tidal observations prior to the establishment of the present sea level network in Malaysia; stipulate the objectives of the network; the description of the model of the tide gauges and their date of establishment; the types of tides available in Malaysia and also the policy of the Department regarding the dissemination of tidal data.
2. Background
Since colonial times, way back from the nation's independence in 1957, there were quite a number of sites selected for tide measurements by various government agencies such as in Kuantan (1908), Port Dickson (1930), Pulau Pinang (1955 and 1958), Pulau Lakei (1950-1951 & 1955-1956) and Tawau (1918). The observation periods ranged from a month to a year. However, the records and the methods of observation were not available in the Department. There was no long term planning for sea level measurements and monitoring of sea level changes at that time. The measurements were merely used to define local vertical reference datums for selected places to provide height essential to the development of the nation's infrastructure. Because of these measurements, a few datums had been established, namely Land Survey Datum 1912 (LSD 1912) in Peninsular Malaysia, Pulau Lakei Datum in Sarawak 1960, Kota Kinabalu Datum 1975 and Befry Datum 1918 in Sabah. These datums are currently still in use.
In 1963-1964, there were attempts to establish a tide station network along the coast of Peninsular Malaysia. The attempts did not materialise due to the lack of expertise and experience. The urge to set up a tidal observation network finally came to light again after the tidal observation project was initiated in 1981. The technical aids were provided by the Hydrographic Department, Maritime Safety Agency, Japan and funded by the Japan International Cooperation Agency (JICA) under the Colombo Plan. In a span of 6 years (1981-1986), 12 tide stations were established.
When DSMM took over the maintenance and custody of Sabah tide gauges at Kota Kinabalu, Tawau and Sandakan in 1984, the stations were not in good condition and eventually the stations were not functioning due to either break-down or other reasons (Takanori Imanishi, October 1991). The stations were later revived in 1987 for Kota Kinabalu and Tawau stations while the Sandakan station was only revived in 1993.
Same problems were encountered in Sarawak when DSMM took over the responsibility of maintaining the tide gauges from the State Land and Survey, Sarawak in 1990. Two stations, namely Bintulu and Miri, were restored in 1991.
3. Objectives Of The Tidal Observation Network
The objectives of the network are:
a) To carry out continuous tide observations at these locations for at least 19 years to complete a cycle of the regression of the moon's nodes.
b) To process the observed tidal data and to obtain the mean sea level values at the selected tide stations.
c) To analyse the observed tidal data and obtain the Harmonic Constants for tidal prediction.
d) To publish records of Tidal Observation and Tide Prediction Tables annually.
e) To study the tidal characteristics along the coast of West and East Malaysia.
4. Malaysian Tidal Network
There are 21 tidal stations in Malaysia. 12 are in West Malaysia and 9 are in East Malaysia. Table 1 below shows the location, date of establishment and type of tide gauge used at all the tidal stations.
Table 1: Locations of Tide Stations and Dates of Establishment.
No. Location Date of Type of Tide Gauge
Establishment Used
1 Pelabuhan KelangDec. 1983 Kyowa Shoko LTT-3AD
Oct. 1993 Kyowa Shoko DFT-1
2 Johor Bahru Dec. 1983 Kyowa Shoko LTT-3AD
3 Tanjung Gelang Dec. 1983 Kyowa Shoko LTT-3AD
4 Pulau Pinang Nov. 1984 Kyowa Shoko LTT-3AD
5 Lumut Nov. 1984 Kyowa Shoko LTT-3AD
6 Tanjung Keling Nov. 1984 Kyowa Shoko LTT-3AD
7 Cendering Oct. 1984 Kyowa Shoko LTT-3AD
8 Pulau Langkawi Nov. 1985 Kyowa Shoko LTT-3AD
9 Kukup Nov. 1985 Kyowa Shoko LTT-3AD
10 Pulau Tioman Nov. 1985 Kyowa Shoko LTT-3AD
11 Tanjung Sedili Oct. 1986 Kyowa Shoko LTT-3AD
12 Geting Oct. 1986 Kyowa Shoko LTT-3AD
13 Kota Kinabalu Jun. 1987 LTT-3AD
14 Tawau Jun. 1987 LFT-V
Aug. 1994 Kyowa Shoko DFT-1
15 Miri Feb. 1991 Kyowa Shoko LTT-3AD
Jan. 1994 Kyowa Shoko DFT-1
16 Bintulu Jul. 1991 Kyowa Shoko LTT-3AD
Sep. 1993 Kyowa Shoko DFT-1
17 Sandakan Aug. 1993 Kyowa Shoko DFT-1
18 Kudat Oct. 1995 Kyowa Shoko DFT-1
19 Lahat Datu Oct 1995 Kyowa Shoko DFT-1
20 Labuan Dec. 1995 Kyowa Shoko DFT-1
21 Kuching Jan. 1996 Kyowa Shoko LTT-3AD
Figure 1 shows the locations of all the tidal stations in Malaysia.
5. Types of Tides
The classifications of tides are based on the value of the ratio (F) of the sum of the amplitudes of the two main diurnal components (K1 and O1) to the sum of the amplitudes of the two main semi-diurnal components (M2 and S2).
a) Semi-diurnal type .....Ratio(F) < 0.25
b) Mixed (Dominant semi-diurnal) ..... 0.25 < Ratio (F) < 1.5
c) Mixed (Dominant diurnal) ..... 1.5 < Ratio (F) < 3.00
d) Diurnal type ..... Ratio (F) > 3.00
Figure 2 shows the ratio (F) of the tide found in Malaysia.
In Peninsular Malaysia, it is dominated by semi-diurnal and mixed (Dominant semi-diurnal) tide except Cendering station which has a mixed (Dominant Diurnal) tide. On the other hand, the tide in East Malaysia is either dominated by mixed (Dominant semi diurnal) tide or mixed (Dominant diurnal) tide. There is no diurnal tide available in Malaysia.
6. Dissemination of Tidal Information
The Department of Survey and Mapping Malaysia produces two publications annually. They are
(a) Record of Tidal Observation and
(b) Tide Prediction Tables
The tidal predictions of all the stations are based on a set of 60 harmonic constituents, analysed from the yearly observation. The final predicted tide values that would be adopted for Tide Prediction Tables are the mean of the past 5 years of good observations.
The DSMM entertains requisition for tidal data from various agencies both within the country and also those overseas. Agencies and institutions both within or overseas alike can request in advance a copy of the publications to be delivered annually. Requests must be directed to
The Director-General of Survey and Mapping Malaysia 1 Floor, Bangunan Ukur Jalan Semarak 50578 Kuala Lumpur West Malaysia.7. Conclusions
With the newly installed tide gauges at Kudat, Lahat Datu, Pulau Labuan and Kuching in the late 1995 and early 1996, the tidal observation network in Malaysia can be considered as adequate and evenly distributed along the Malaysian coast. However the department may consider from time to time to increase the number of tide stations when the need arises.
Until the end of 1995, almost all the tide stations in the West Malaysia have collected at least 9 years of tidal data. On the other hand, only Kota Kinabalu and Tawau in Sabah have collected 8 years of tidal data, the rest of the stations in the East Malaysia are still very new.
So far, there is still no comprehensive and long term investigation into the tidal phenomena and mean sea variation for the whole of Malaysia. However, the tidal phenomena and mean sea level variation around Peninsular Malaysia had been carried out by Mr. Shigeru Toyoshima based on 6-9 years of tidal data from all the 12 tidal stations. A paper entitled Tidal Phenomena and mean sea level variations around Peninsular Malaysia was presented in a seminar Tide and Tidal Phenomena in 1994 in Kuala Lumpur.
