Urgent Measure of Geospatial Parameters for Flood Modeling in Indonesia

Indonesia is prone to flood. Many areas including cities have a suffering flood in history until these recent days.  Jakarta city, for example, had suffering flood since Dutch colonial time a few hundred years ago and even earlier until this recent year 2018. Besides Jakarta, Indonesia has other big cities like Bandung, Semarang, Surabaya and Medan which frequently suffered from the flood. Growing cities like Langsa, Pekanbaru, Palembang, Pamanukan, Garut, Cirebon, Pekalongan, Demak, Bojonegoro, Banjarmasin, Gorontalo, Bima are also suffering flood in almost regularly. The flood condition is different from time to time due to rain intensity and rivers capacity are leading to disaster.  Low land areas such as coastal areas and peatland areas in many regions of Indonesia are experiencing the same disaster. Adaptation and mitigation should be taken against this flood disaster. In order to find the best adaptation and mitigation, first, we must understand the characteristic of the flood by creating flood models. Essential parameters of flood modeling would include geospatial parameters (e.g., Digital Elevation Model, Land use, and rivers geometry).  Unfortunately for Indonesia's case, these geospatial parameters of the flood are still relatively weak.  We can see that several flood models of Indonesia are in low accuracy spatially and temporarily. So, the measure of geospatial parameters is urgent. This paper will highlight this urgency

Adaptation of ‘Early Climate Change Disaster’ to the Northern Coast of Java Island Indonesia

In the last few decades, the tidal inundation and abrasion along northern coast of Java Indonesia have been grown very rapidly. These situations are far beyond the geological scale. These are way too fast. Time series of high resolution satellite image data shows very clearly the tidal inundation and abrasion existence. In the recent years in fact the tidal inundation is obviously going further deeper inland. Many of urban and other areas like farming area, fishpond, etc. have been suffered tidal inundation and becoming worse in times. First it was only few centimetres of inundation and come only at a high tide, but now it can be more than a half of meter and coming at regular tide, and even has comes permanently in certain places. Many of the area along northern coast of Java are also suffering abrasion due to frequently of bad weather with storm surge strike the coastal area. What is happening to the northern coast of Java Island Indonesia is one most clear pictures of ‘early climate change disaster’. Adaptation has been created against this ‘early climate change disaster’ such as build dykes, elevate the land, houses, infrastructures, etc. This paper will tell in details and comprehensively regarding adaptation of ‘early climate change disaster’ to the northern coast of Java Island Indonesia. This is one way to remain on what would happen in the future world wide as the global climate change consequences are finally coming. We have seen the news of the projection model of sinking of coastal cities in the world, vanishing Islands around the Pacific, etc. in the future

The Use of GNSS GPS Technology for Offshore Oil and Gas Platform Subsidence Monitoring

Due to oil and gas exploitation, offshore oil and gas platform may experience subsidence. Continuing subsidence may deform the platform infrastructures, adding the risk for any failure on the platform objects. The failure means disaster. Therefore the subsidence information is mandatory for risk assessment and safety requirement. Repeatedly or continuous monitoring of accurate positions on the platform by using global navigation satellite system global positioning system (GNSS GPS) technology may reveal the changing of even small positions which are representing subsidence on the platform. This chapter will be deeply discussed on the use of GNSS GPS technology for offshore oil and gas platform subsidence monitoring, especially in Indonesia, the archipelago country where long baseline between reference station in the land and monitoring station at the sea slightly exists. The capability and especially the high performance of this technology on deriving subsidence information along with data sample of long baseline will be highlighted

The Potency of the Modernized GNSS Signals for Real-Time Kinematic Positioning

GNSS positioning has become popular in the past decade as an efficient method of precise and real-time positioning. It is relatively low cost and ease-of-use. Up to now, several parameters were defined to characterize the performance of real-time positioning: availability, precision, accuracy. This article evaluates the performance of signal linear combinations for real-time positioning, both for static as well as the kinematic positioning. This article starts with the investigation of linear combinations (LC) rising from the carrier frequencies of the GNSS systems. Some Linear Combination shows potential benefits in carrier phase integer ambiguity resolution, particularly utilizing the Galileo and Beidou signal phase carrier. For each system, a set of combinations was studied, analyzed, and then selected during the development of GNSS positioning method utilizing the Least-squares Ambiguity Decorrelation Adjustment (LAMBDA). Special signal selection can affect the estimated position and its standard deviation. To further analyze, the results obtained from data processing are compared with respect to baselines and signals. The ambiguity fixing rate is correlated with the baseline length and the method as well as the signals that were used. The analysis of the measurement noise level was first conducted to set a baseline for the real-time GNSS positioning application. According to the results and to assess the data quality and positioning performance of GNSS in respect with GPS (Global Positioning System), an experimental test has established using MGEX data. This research investigates the satellite visibilities, multipath, Signal to Noise Ratio (SNR), and positioning performance. It is shown that in every epoch, at least 8 satellites are visible. The SNR’s are up to 60 dBHz, the code multipath residuals varies within ~1 m, while the phase residuals varies by about ~2 cm. hence the modernized GNSS signals have potencies to improves the RTK positioning

Insight into the Correlation between Land Subsidence and the Floods in Regions of Indonesia

Land subsidence by definition is the lowering of ground level from certain elevation references. The rates of subsidence can commonly vary between 1 and 20 centimeters per year and even more in certain places. Subsidence produces impacts such as infrastructure damage, problems with drainage, wider expansion of flood water, as well as tidal inundation (flooding by sea water at coastal areas experiencing land subsidence). These impacts are quite costly. All this is disastrous. In a number of regions of Indonesia, land subsidence and negative impacts in the shape of flooding and tidal inundation clearly exist. In Jakarta and Bandung we can see that the subsiding areas close to rivers frequently suffer from flooding. Tidal inundation is a regular feature at subsiding coastal areas such as Jakarta, Blanakan, Semarang, and Demak. Since these negative impacts are clearly formed a disaster while mitigation and or adaptation is still a big homework, in this case for better adaptation and mitigation in the future, understanding deeply the correlation of land subsidence and flooding is necessary as discused in this chapter. We conclude that the correlation is quite tremendous and indeed producing a disaster

Deformation Study of Papandayan Volcano using GPS Survey Method and Its Correlation with Seismic Data Observation

Papandayan volcano located in the southern part of Garut regency, around 70 km away from Bandung city, West Java. Many methods carried out to monitoring the activities of volcano, both continuously or periodically, one of the monitoring method is periodically GPS survey. Basically those surveys are carried out to understand the pattern and velocity of displacement which occurred in the volcano body, both horizontally and vertically, and also others deformation elements such as; translation, rotation and dilatation. The Mogi modeling was also used to determine the location and volume of the pressure source which caused deformation of volcano body. By comparing seismic activity and the deformation reveal from GPS measurement, before, during and after eruption, it could be understood there is a correlation between the seismicity and its deformation. These studies is hoping that GPS measurement in Papandayan volcano could be one of supported method to determine the volcano activities, at least in Papandayan volcano

The Effect of TLS Radome on GNSS Precise Positioning

This article presents the results of a test carried out to check the usability of spherical TLS targets as GNSS antenna radomes (herein called TLS radomes). On different days, the survey was conducted using two GNSS antennas, one of them with a TLS radome. Measurements were made using 2 roof pillars on the rooftop as base-rover pillars with little obstruction. The measurements were carried out for approximately 1 hour in every scenario. The software used for data processing is MATLAB-based software and the raw data were processed using the double difference (DD) strategy to obtain optimal results. The results of the data processing indicated that the TLS radome has no significant influence on availability and accuracy of estimated position. The signals are slightly attenuated by the radome (1-2 dBHz) and the noise level is slightly increased but both effects are negligible for practical purposes. However, we found that the antenna should be calibrated with the TLS radome to clarify apparent minor phase center eccentricities (1-2 mm) and to reduce systematic effects with long periods (few minutes) and amplitudes up to about 5 mm which are likely due to phase center variations

The Effect of Highway Vibration to The Hills Slope Stability by an Integrated GPS-Vibration Data Processing

Bandung-Jakarta, Indonesia highway have high density vehicles pass even often jammed. High activity of vehicles cause repeated vibrations and occur continuously. In case, the highway that divides the hills. The passing vehicles give rise repeatedly vibration and indicated disturbance of hillside slope stability. Vehicles vibration depend on speed, weight, number of vehicles and road construction materials. A method in question is counting a vehicle volume and determine the volume pattern of the vehicle. The magnitude of vibration is function of the object distance from the sources. The magnitude of the vibration effect is very dependent on the geological structure of hills formation. Hilly slope stability indicates experiencing interference if the object or material slope changes position or displacement. GPS observation give position changes and its displacement. The effect of Toll road vibration to slope stability is known by GPS and Vibration simultaneous measurement. Data acquisition used six unit GPS receivers and six unit vibration sensor which is installed on the hillside beside the highway. Integrated data processing techniques using Empirical Mode Decomposition (EMD). Integrated GPS-Vibration data are implemented to find actual displacement which are caused by highway vibration