The Bintan MOS development: contribution of ideas to realize Nusantara marine observation network

1 Department of Marine Science, Marine Science and Fisheries Faculty, Raja Ali Haji Maritime University, Tanjungpinang 29111, Indonesia. 2 Department of Marine Science and Technology, Fisheries and Marine Science Faculty, IPB University, Bogor 16680, Indoenesia. 3 Laboratory of Marine Instrumentation and Robotics, Department of Marine Science and Technology, IPB University, Bogor 16680, Indoenesia. 4 Magister Program of Environment Science, Raja Ali Haji Maritime University, Tanjungpinang 29124, Indonesia. 5 Marine and Coastal Resources Research Center, Raja Ali Haji Maritime University, Tanjungpinang 29124, Indonesia.


Introduction
Marine and weather dynamics usually affect the various human activities in coastal areas (Halpern et al., 2008). This potentially increase the risk of coastal communities to climate change (Mafi-Gholami et al., 2020). To predict the impact of this changes, one of the important steps is to monitor weather and sea water dynamics. Previous studies recommended that continuous observations need to be carried out over a long period before the information is considered reliable. Such technique has to be carried out in realtime before being considered as a tool in decision making at local, regional, and global scales (Dexter and Summerhayes, 2010).
Data collection on the field, especially in marine waters, has its own challenges as the samples obtained are usually few, expensive, require a lot of time and high level of difficulty (Glenn et al., 2000). Therefore, an extended real-time monitoring is the best solution to fully understand the dynamics of these changes and the resultant impacts on coastal and marine resources (Moersdorf and Meindl, 2003;Ruberg et al., 2007;Lynch et al., 2014).
Networks of marine observation stations have been developed in several developed countries (Isemer, 1995;Glenn et al., 2000;Van-Den-Broeke et al., 2004;Conlee and Moersdorf, 2005;Novellino et al., 2014). However, for Indonesia, this system has not been fully Incorporated with the Internet of Things (IoT) hence, data collection is still short-term and temporal.
When these monitoring and observations are carried out in a continuous and real-time manner, it promotes the complete understanding of the global Depik Jurnal Ilmu-Ilmu Perairan, Pesisir dan Perikanan Volume 10, Number 1, Page 53-59 Apdillah et al. (2021) climate dynamics and impacts on human life. Meanwhile, this is only achievable through long-term time analysis of the key parameters obtained at permanent observation station.
Therefore, the development of a Marine Observation System (MOS) located in Bintan aims to provide data and information in relation to coastal weather conditions and sea-level dynamics as a pioneering form of national maritime technology independence.

Materials and Methods Location and times
The marine stations were located on Bintan Island, Riau Islands Province, Indonesia ( Figure 1). Meanwhile, the MOS were installed in 2 places namely, Berakit Station (on the beach) and Bakau Bay Station (at the sea). The detailed position of MOS on Bintan Island is presented in Table 1 meanwhile, the initiation for the Bintan MOS development commenced from May 2018 to January 2020.

Tools and materials
This study was performed using Automatic Weather Station (AWS) and Mobile Tide and Water Level Instrument (MOTIWALI) based on acoustic sensor.

Automatic weather station design
AWS is automatically designed to measure weather data such as wind speed and direction, temperature, as well as humidity. The current AWS was developed by (Kusumah et al., 2016;Syafi'i, 2018). This study was conducted using AWS with an automatic transmission system utilizing GSM (Global System for Mobile) as a medium for delivering information. This instrument is useful for obtaining data quickly, economically, and practically.
The instrument material was designed to be waterproof in order to preserve the sensor performance. Besides, the cup counting on the wind speed gauge is half of a plastic ball (Figure 2). wind sensor.
The electronic box was made with glass and plastic, to prevent contact with rain, dust, and direct sunlight. Furthermore, the electronic system was divided into several circuits including main, sensor, transceiver, and data logger. The main circuit used Arduino as the brain hence, it gives instructions to other components. The Arduino Promini and Uno receiver were connected to the sensor together with the data sending module and ethernet shield respectively. In addition, the Arduino Promini was also connected to RTC (Real Time Clock), micro SD (Secure Digital) and indicator led while three sensors were connected to the transmitter. Opto rotary was connected to pin D2 (Digital Pin), Magnetor HMC5883L series to pins A4 and A5 (I2C), and the DHT-11 series temperature and humidity sensor to pin D3 (Digital Pin).
The transceiver circuit was made with the KYL200 series modules and functions for sending and receiving signal. It is connected to the MAX3232 series IC converter. The logger series was used to store data (sensors & time). In addition, the RTC DS1307 series was connected to pins A4 and A5 (I2C), while the micro SD Adapter was connected to pins D11 (miso), D13 (Serial Clock), D12 (mosi), and D10 (cs) Serial Peripheral Interface (SPI) led indicators, connected to pin D9.
The main energy source for the transmitter circuit was a 12 Volt battery, connected to a solar panel whereas, a 5V 1A adapter was used for the receiver circuit to convert the ac to dc, needed for energy in the data logger circuit.
Depik Jurnal Ilmu-Ilmu Perairan, Pesisir dan Perikanan Volume 10, Number 1, Page 53-59 Apdillah et al. (2021) The AWS software was designed to perform functions such as: reading, sending, receiving, writing (sensors and timing), and data storage. The flow of the software is shown in Figures 3 and 4.

Acoustic tide gauge/MOTIWALI
Sea-level dynamics were measured using tide gauges with MOTIWALI (Mobile Tide and Water Level Instrument). The principle of this instrument is based on acoustics (ultrasonic sound waves). It works by simply calculating the time taken for one acoustic pulse to hit the sea level and then return to the sensor, the travel time is then converted to distance. Furthermore, MOTIWALI ( Figure

Marine observation system Sensor and data acquisition system
A sensor is a device which convert physical quantities into electrical hence, conditioning it to be processed electronically. The quantities measured in this system include temperature, humidity, wave direction, speed and sea level.
The sensor output is characterized with few changes and tends to be unstable, therefore, it requires a buffer circuit that stabilize the output changes while amplifying the sensor signals. This output was then relayed to the ADC (Analog to Digital Converter) system to convert the analog sensor into digital signals which were further processed by the microcontroller. The ADC used in the Bintan MOS system has a built-in feature of the microcontroller ( Figure 6). This feature included, 10bit precision (1024 possible outputs), working voltage 0-5 volts, frequency of 12,500 kHz, and successive approximation type.
The Arduino Nano type microcontroller was used and performed three main functions which include (1) as an ADC which is a built-in feature of the instrument, (2) signal processor that has been read by the ADC, and arrange data into a format and Depik Jurnal Ilmu-Ilmu Perairan, Pesisir dan Perikanan Volume 10, Number 1, Page 53-59 Apdillah et al. (2021) regulates the timing and synchronization of data transmission to the sending system (transmitter), (3) transmit and receives responses from/to the sending system via the RS232 line (a circuit that converts parallel paths to serial).

Transmiter system
The data transmission system used the GSM frequency (900 MHz or 1800 MHz). Data transmission was carried out in the form of SMS (Short Message Service). Meanwhile, the GSM module used was Wavecom which receive data and commands from the microcontroller and then send data using the SMS service on GSM.

Power supply
The power supply used for operating the tools or sensors include solar power, battery / 12 Volt Accu batteries. Figure 6. Bintan MOS prototype.

Results
Instrument installation and data collection were carried out from July 2018 to May 2020. The data from each sensor ranged from 15,132 to 212. 722. Moreover, several temperature and humidity data were later sent in December 2019, as the sensors were scheduled for repair (maintenance). The results of Bintan MOS development at Berakit and Bakau Bay Stations are presented in Figure 7, and detailed data characteristics are presented in Table 2.

Wind speed
The wind speed data were collected per 5 minutes for ± 20.25 months. During this period, there were data gaps at certain times ( Figure 8) due to several disturbances in communication and transmissions, sensors, repair of equipment, and also from power supply system (batteries and solar panels) due to rainy season conditions. Wind speed ranged from 0.1 -16.61 m / sec, with an average of 3.73 (± 0.02) m /sec.

Air temperature and humidity
Temperature and humidity data were recorded every 5 minutes for ± 17.75 months with a total of 107,387 and 15,132 data units at the Bakau Bay and Berakit station respectively. In addition, the temperature ranged from 23 to 34 0 C, with an average of 29 (± 1.2) 0 C on Bintan Island while the air humidity ranged from 40 -92%, with an average of 78 (±2.0) %. Detailed information on temperature and humidity data are presented in Figure 9.

Tidal
The tidal data were collected every 3 minutes for ± 20.25 and 23.75 months at Bakau Bay and Berakit Depik Jurnal Ilmu-Ilmu Perairan, Pesisir dan Perikanan Volume 10, Number 1, Page 53-59 Apdillah et al. (2021) stations respectively. Data recording was carried in real-time via a cellular operator however, at the Berakit station, there are data gaps which lasted for approximately six months, as a result of disruption to the GSM-based sending system. The tidal height result in Bintan waters shows that there are high and low tide occurs two times in a day while the mixed tide tend to double daily. Moreover, the tide height ranged from 134 -282 cm, with an average of 227 cm (Figure 10).

Discussion
The result indicates that data obtained from Bintan MOS are reliable. Furthermore, the performance test and calibration of the Automatic Weather Station instrument for wind speed had a RMSE (Root Mean Squared Error) value of 0.51 m/s with an R2 of 0.87 (p <0.05) (Kusumah et al., 2018). Meanwhile, the MOTIWALI instrument produced distinctive result in measuring sea level distance using a transducer, as reported by Bemba et al. (2019) with an RMSE value of 1.86 cm amplitude (Khatimah et al., 2016).
The tidal height measurement using Bintan MOS have also been compared with the results from BIG (Geospatial Information Agency) data, available on http://tides.big.go.id/pasut/index.html with a R 2 correlation coefficient of 0.83 (p<0.05). Comparisons were made between a 9-day tidal data sample from 26 December, 2019 to 3 January, 2020. It showed that the instrument's performance is scientifically justified. The linear regression graph for the water level of the Bintan MOS data with the tide height of BIG (Geospatial Information Agency) data are presented in Figure 11.
Several reasons for selecting GSM cellular telephone include, availability of the infrastructure network therefore, it provides convenience by not creating a new network that requires high costs. It also allows fast data transfer, hence, data are received in relatively large capacity. In addition, the operational costs are relatively cheap compared to the existing system where data access seldom require permission from the satellite owner but carried out directly.
The observation system developed consist of several parts including sensor and data acquisition system supported by the microcontroller as well as sending and receiving system (transceiver). Furthermore, the sensor system is supported by a microcontroller, power supply, and data sending system using the GSM frequency (900 MHz or 1800 MHz) with SMS (Short Message Service). Due to the affordability of this service, its development is important for campuses and environmental stakeholders which have limited funding.
There are still few limitations in the Bintan MOS development, such as the type and number of sensors providing real-time data which consist of five main sensors, including wind, temperature, humidity, and sea level. Besides, the Bintan MOS also provide information on other environmental parameters such as, current speed, waves, and aquatic biota monitoring (Underwater Television System), however, this information are not yet available online.
The urgency to incorporate marine observation station (MOS) to current conditions are as follows: (1) Practically, no maritime institution in Indonesia Depik Jurnal Ilmu-Ilmu Perairan, Pesisir dan Perikanan Volume 10, Number 1, Page 53-59 Apdillah et al. (2021) implements operational oceanography, involving (MOS) which routinely generate and transmit day to day, directly (real-time) data to be processed and further used for the benefit of marine development; (2) The temporal and spatial variations of Indonesian sea are very high and difficult to understand with one or two observation points. It takes many connected locations or observation networks to obtain a more complete description of the country's ocean dynamics. Therefore, it is necessary to develop a marine observation network in this archipelago (Nusantara); (3) Each marine institution has the ability and resources to establish a marine observation station in its respective location. The formation of MOS network with other marine organizations provides greater and wider benefits.  Furthermore, the development of Bintan MOS implies that this system is also applicable in forecasting marine conditions and existing biological resources, monitoring water quality (Kusuma et al., 2020;Xu et al., 2019), marine mammals (Peng et al., 2020), mitigation and management of ecosystems as well as coastal environmental resources (Durante et al., 2020). Meanwhile, a major impact on the marine community is the availability of scientific research facilities. In addition, the adoption and development of this system elsewhere is useful for marine researchers as access to data exchange to fully understand or compare coastal weather fluctuations in western and eastern Indonesia or tropical and subtropical marine weather.
When every state and private university with fisheries and marine department in Indonesia develops and manages a customized MOS, data from a wide range of marine phenomena becomes comprehensively accessible (Figure 12). Hence, it is possible to establish a marine observation forum for state and private universities in Indonesia to openly share data. In addition, forum members are to be granted access to baseline data, for collaboration in scientific publication.
This network system is more effective and efficient, as each manager is only responsible for respective MOS, both in development and in maintenance. MOS sustainability requires simple strategy which include, developing the existing instruments and network activities, forming strategic partnerships, giving priority to the development of human resource capacity and web-based communication infrastructure. With consistent implementation, the MOS Nusantara is achieved as a form of self-sufficiency in marine technology in Indonesia.

Development opportunities
Due to past experience of receiving partially miss (blank data), it is necessary to optimize the power supply system (battery and solar panels) to ensure proper running of data reception and transmission. The five sensors in Bintan MOS are integrated with one central power supply system. This technique effectively reduces materials consumption and efficient in material shopping. However, the challenge is that when the power supply system is faulty, then all sensors are unable to receive or send the ordered data. Hence, optimizing the power supply system performance includes the capacity to provide energy when needed. Furthermore, lack of power potentially weakens the battery, while excess power deteriorates the battery's ability as a risk of using a directly connected solar panel.
To maximize the implementation of Bintan MOS, the output data are to be presented on android devise as coastal communities and fishermen are more familiar with this system hence, data become easily accessible. In addition, data presentation potentially becomes more effective, especially with the use of simple features such as water icons for tidal information, wind icons for wind speed, and others.