16 research outputs found

    A review of geothermal mapping techniques using remotely sensed data

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    Exploiting geothermal (GT) resources requires first and foremost locating suitable areas for its development. Remote sensing offers a synoptic capability of covering large areas in real time and can cost effectively explore prospective geothermal sites not easily detectable using conventional survey methods, thus can aid in the prefeasibility stages of geothermal exploration. In this paper, we evaluate the techniques and approaches used in literature for the detection of prospective geothermal sites. Observations have indicated that, while thermal temperature anomalies detection have been applicable in areas of magmatic episodes and volcanic activity, poor resolution especially from space borne data is still a challenge. Consequently, thermal anomalies have been detected with some degree of success using airborne data, however, this is mostly in locations of known surface manifestations such as hot springs and fumaroles. The indirect identification of indicator minerals related to geothermal systems have been applied using multispectral and hyperspectral data in many studies. However, the effectiveness of the techniques relies on the sophistication and innovative digital image processing methods employed to sieve out relevant spectral information. The use of algorithms to estimate land surface temperature and heat fluxes are also applied to aid thermal anomaly detection, nevertheless, remote sensing techniques are still complementary to geologic, geophysical and geochemical survey methods. While not the first of its kind, this review is aimed at identifying new developments, with a focus on the trends and limitations intrinsic to the techniques and a look at current gaps and prospects for the future.Keywords: Geothermal, remote sensing, thermal anomalies, indicator minerals, multispectral, hyperspectra

    Penggunaan Citra Landsat untuk Pendeteksian Anomali Suhu Permukaan Sebagai Indikasi Keberadaan Manifestasi Panas Bumi. Studi Kasus: Sipoholon, Indonesia

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    Sipoholon merupakan sebuah kecamatan yang terletak di Kabupaten Tapanuli Utara, Sumatera Utara yang dilewati oleh Sistem Sesar Sumatera. Berdasarkan peta Geologi Lembar Sidikalang, ditemukan adanya manifestasi panas bumi berupa mata air panas (hot spring) di daerah tersebut. Keberadaan manifestasi ini menunjukkan adanya sistem panas bumi yang bekerja di bawahnya. Keberadaan manifestasi panas bumi di suatu daerah akan berpengaruh terhadap suhu permukaan tanah di daerah tersebut. Pendeteksian anomali suhu permukaan tanah dapat dilakukan dengan berbagai cara. Salah satu metode yang mudah untuk dilakukan yaitu menggunakan Citra Penginderaan Jauh. Citra Landsat merupakan salah satu citra penginderaan jauh yang dapat digunakan untuk mendeteksi anomali suhu permukaan. Penelitian ini bertujuan untuk mendeteksi anomali suhu permukaan sebagai indikasi adanya manifestasi panas bumi di Sipoholon, Sumatera Utara menggunakan Citra Landsat. Band 10 dan band 11 yang merupakan thermal infrared (TIR) diolah untuk mendapatkan suhu kecerahan (brightness temperature). Band 4 dan 5 digunakan untuk menghitung kerapatan vegetasi (NDVI) dan emisivitas suhu permukaan. Gabungan dari band 10, band 11 dan NDVI digunakan untuk menghitung nilai suhu permukaan tanah (Land Surface Temperature). Data lapangan berupa suhu mata air panas dan suhu permukaan tanah  diambil untuk melakukan verifikasi terhadap analisis citra yang telah dilakukan. Hasil analisis citra menunjukkan bahwa suhu permukaan di lokasi penelitian berkisar antara 16,7°C sampai dengan 28,4°C. Anomali suhu tinggi berada di daerah yang dilewati oleh sesar sumatera. Hasil verifikasi di lapangan menunjukkan hasil yang selaras, terdapat mata air panas di daerah yang dilewati oleh sesar sumatera dengan suhu 35,7 °C – 64,4°C. Sedangkan suhu permukaan tanah berkisar antara 31,3°C – 48,7°C. Hal ini menunjukkan bahwa citra landsat berupa suhu permukaan tanah (LST) dapat digunakan untuk mendeteksi anomali suhu permukaan sebagai indikasi adanya sistem panas bumi di suatu daerah untuk memudahkan pengerucutan lokasi pada tahap eksplorasi

    Assessment of Landsat 8 TIRS data capability for the preliminary study of geothermal energy resources in West Sumatra

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    West Sumatra is one of has big geothermal energy resources potential. Remote sensing technology can have a role in geothermal exploration activity to measure the distribution of land surface temperatures (LST) and predict the geothermal potential area. Main study to obtain the assessment of Landsat 8 TIRS (Landsat`s Thermal Infrared Sensor) data capability for geothermal energy resources estimation. Mono-window algorithms were used to generate the LST maps. Data set was combined with a digital elevation model (DEM) to identify the potential geothermal energy based on the variation in surface temperature. The result that were derived from LST map of West Sumatra shows that ranged from -8.6 C0 to 32.59 C0 and the different temperatures are represented by a graduated pink to brown shading. A calculated result clearly identifies the hot areas in the dataset, which are brown in colour images. Lima Puluh Kota, Tanah Datar, Solok, and South Solok areas showed the high-temperature value (Brown) in the range of 28.1 C0 to 32.59 C0 color in images which means that they possess high potential for generating thermal energy. In contrast, the temperatures were lower (Pink) in the north-eastern areas and the range distribution was from-8.5 C0 to 5 C0

    IDENTIFIKASI STRUKTUR GEOLOGI DAN PENGARUHNYA TERHADAP SUHU PERMUKAAN TANAH BERDASARKAN DATA LANDSAT 8 DI LAPANGAN PANASBUMI BLAWAN

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    This paper presented used remote sensing method for identification geological structure on Blawan-Ijengeothermal field and its system. Remote sensing data, specifically Landsat 8 and DEM SRTM, provide lineaments from the 753 multispectral band and the land surface temperature (LST) from single thermal infra red band using a retrieval method. Surface emissivity was determined based on Normalized Difference Vegetation Index (NDVI) of study area. Remote sensing analysis is good approach to identification of geological structure from surface that control thermal manifestation in Blawan geothermal field. It shows Blawan fault is the main structure in geothermal field which associated with high LST and hot springs. Interpretation indicated reservoir of Blawan-Ijen geothermal system spread from Plalangan to southwest area. ABSTRAK Penelitian ini bertujuan untuk mengidentifikasi struktur geologi dan gambaran sistem panasbumi Blawan-Ijen dengan aplikasi penginderaan jauh. Data penginderaan jauh khususnya citra multispektral komposit 753 Landsat 8 dan DEM SRTM digunakan sebagai data untuk mendelineasi struktur patahan di permukaan. Suhu permukaan tanah diperoleh dari pengolahan citra thermal inframerah Landsat 8 dengan bantuan metode semi empiris. Emisivitas permukaan diperoleh berdasarkan klasifikasi indeks vegetasi NDVI daerah penelitian. Analisis data penginderaan jauh merupakan pendekatan yang cukup baik dalam mengidentifikasi struktur geologi yang mengontrol manifestasi panasbumi Blawan. Hasil interpretasi menunjukkan patahan Blawan adalah struktur utama di daerah geothermal Blawan yang berasosiasi dengan suhu permukaan tanah yang tinggi dan deretan mata air panas. Interpretasi mengindikasikan reservoir sistem panasbumi Blawan berada di bawah permukaan Plalangan dan menerus dari Plalangan menuju arah barat daya daerah penelitian

    Exploring Renewable Energy Resources Using Remote Sensing and GIS—A Review

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    Renewable energy has received noteworthy attention during the last few decades. This is partly due to the fact that fossil fuels are depleting and the need for energy is soaring because of the growing population of the world. This paper attempts to provide an idea of what is being done by researchers in remote sensing and geographical information system (GIS) field for exploring the renewable energy resources in order to get to a more sustainable future. Several studies related to renewable energy resources viz. geothermal energy, wind energy, hydropower, biomass, and solar energy, have been considered in this paper. The focus of this review paper is on exploring how remote sensing and GIS-based techniques have been beneficial in exploring optimal locations for renewable energy resources. Several case studies from different parts of the world which use such techniques in exploring renewable energy resource sites of different kinds have also been included in this paper. Though each of the remote sensing and GIS techniques used for exploration of renewable energy resources seems to efficiently sell itself in being the most effective among others, it is important to keep in mind that in actuality, a combination of different techniques is more efficient for the task. Throughout the paper, many issues relating to the use of remote sensing and GIS for renewable energy are examined from both current and future perspectives and potential solutions are suggested. The authors believe that the conclusions and recommendations drawn from the case studies and the literature reviewed in the present study will be valuable to renewable energy scientists and policymakers

    Seasonality of MODIS LST over Southern Italy and correlation with land cover, topography and solar radiation

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    AbstractLand Surface Temperature (LST) is a key variable in the interactions and energy fluxes between the Earth surface and the atmosphere. Satellite data provide consistent, continuous and spatially distributed information on the Earth's surface conditions among which LST. Ten years of NASA-MODIS day-time and night-time 1 km LST data over Southern Italy have been analyzed to quantify the influence of factors such as topography and the land cover on LST spatio-temporal variations. Results show that topography significantly influence LST variability as a function of the land cover and to a different extent for day-time and night-time data. Moreover, the relation between LST and the influential factors varies with the season during the year. This study contributes to a further understanding of the complex relationship between the spatio-temporal variability of the surface thermal conditions and its driving factors highlighting how these relationships might change within the year

    Monitoring temporal variations in the geothermal activity of Miocene Lesvos volcanic field using remote sensing techniques and MODIS - LST imagery

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    Abstract Many islands of the Aegean Sea show strong geothermal activity due to volcanism in the area. In this paper, Robust Satellite Techniques (RST) are used to isolate, from other known possible sources, those thermal anomalies possibly related to geothermal activity in the Miocene volcanic field of Lesvos Island (Northern Aegean). For this purpose, 12 years (2003–2014) of daily Night-time Land Surface Temperature (LST) products, from Moderate Resolution Imaging Spectroradiometer (MODIS) acquisitions were analyzed. The final dataset contained 770 thermal anomalies whose spatial correlation with geological and structural data of Lesvos - such as caldera rims, ring faults, major tectonic lineaments and hydrothermal alterations mapped by processing SENTINEL-2 MSI satellite images – has been particularly investigated. In the approximately 20 ma geothermal field of Lesvos, geothermal activity seems to be also associated with the extensional regime of the broader area that leads to lithosphere thinning and consequent heat transfer in the multi-fractured terrain of Lesvos through volcanic and tectonic faults. Achieved results seem to confirm the possibility to use RST-based thermal anomalies to identify temporal variations in the geothermal activity probably due to the uplifting and circulation of the hydrothermal waters

    Detection of Geothermal Potential Zones Using Remote Sensing Techniques

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    21 p.The transition towards a new sustainable energy model—replacing fossil fuels with renewable sources—presents a multidisciplinary challenge. One of the major decarbonization issues is the question of to optimize energy transport networks for renewable energy sources. Within the range of renewable energies, the location and evaluation of geothermal energy is associated with costly processes, such as drilling, which limit its use. Therefore, the present research is aimed at applying different geomatic techniques for the detection of geothermal resources. The workflow is based on free/open access geospatial data. More specifically, remote sensing information (Sentinel-2A and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER)), geological information, distribution of gravimetric anomalies, and geographic information systems have been used to detect areas of shallow geothermal potential in the northwest of the province of Orense, Spain. Due to the variety of parameters involved, and the complexity of the classification, a random forest classifier was employed, since this algorithm works well with large sets of data and can be used with categorical and numerical data. The results obtained allowed identifying a susceptible area to be operated on with a geothermal potential of 80 W·m−1 or higherS

    Satellite remote sensing for hydrothermal alteration minerals mapping of subtle geothermal system in unexplored aseismic environment

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    Mapping prospective geothermal (GT) resources and monitoring associated surface manifestations can be challenging and prohibitively expensive in subtle systems especially when using conventional survey methods. Remote sensing offers a synoptic and costeffective capability for identification of GT systems. The objective of this research is to refine and develop methods of identifying unconventional GT systems by evaluating the applicability of the ASTER, Landsat 8 and Hyperion satellite data for mapping hydrothermal alteration indicator minerals as proxy for detecting subtle GT targets in unexplored aseismic settings. The study area is Yankari Park in North Eastern Nigeria, characterized by the thermal springs; Wikki, Mawulgo, Gwana and Dimmil. Spectral Angle Mapper (SAM), Linear spectral Unmixing (LSU) and Mixture Tuned Matched Filtering (MTMF) were comparatively evaluated by using image derived spectra and corresponding library spectra for mapping pixel abundance of GT indicator minerals in a novel and efficient manner. The results indicated that employing image derived spectra from field validated and laboratory verified regions of interest as reference, gives more accurate results than using library spectra around known alteration zones remotely detectable on the imagery. The MTMF provided high performance subpixel target detection with an accuracy of 50-100% and 70-100% subpixel abundance for argillicphyllic- silicic and propylitic alteration mineral assemblages respectively, as compared to less than 10% for the same endmembers when using library spectra. The MTMF is thus best suited for mapping alterations associated with subtle GT systems than the less selective LSU. The per-pixel SAM was unsuitable for target detection of alteration indicators of interest with poor overall accuracy of 33.81% and 0.24 Kappa coefficient at 0.02 radian angle. Results of mapping thermally anomalous pixels do not conform to known locations of the thermal springs signifying the limitations of the current thermal sensors in mapping low temperature GT systems even at 60m spatial resolution. However, examining the spatial correlation of the anomaly areas with the major geologic structure systems from geological map of the study area indicates a close affinity between them and with previously reported thermal gradients within heat insulating sedimentary formations. This study establishes the integrative applicability of Multispectral and Hyperspectral data for mapping subtle GT targets in unexplored regions using in-situ validated alteration mineral mapping and thermal anomaly detection. This has significant implication for the GT green energy industry as the developed methods and GT prospect map could aid the prefeasibility stage narrowing of targets for in-depth geophysical, geochemical, geothermometric and related surveys
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