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Now showing items 1 - 16 of 23

  • Exploration and monitoring geothermal activity using Landsat ETM+images

    Mia, Md. Bodruddoza   Nishijima, Jun   Fujimitsu, Yasuhiro  

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  • Monitoring Heat Losses Using Landsat ETM

    Mia, Md. Bodruddoza   Bromley, Chris J.   Fujimitsu, Yasuhiro  

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  • Impact Assessment of a Major River Basin in Bangladesh on Storm Surge Simulation

    Al Mohit, Md. Abdul   Yamashiro, Masaru   Hashimoto, Noriaki   Mia, Md. Bodruddoza   Ide, Yoshihiko   Kodama, Mitsuyoshi  

    A two-dimensional bay and river coupled numerical model in Cartesian coordinates was developed to find the impact of the river on the simulated water levels associated with a storm along the coast of Bangladesh. The shallow water models developed for both the bay and river were discretized by the finite difference method with forward in time and central in space. The boundaries for the coast and islands were approximated through proper stair steps representation and solved by a conditionally stable semi-implicit manner on a staggered Arakawa C-grid. A one-way nested scheme technique was used in the bay model to include coastal complexities as well as to save computational costs. A stable tidal condition was made by forcing the sea levels with the most energetic tidal constituent, M-2, along with the southern open boundary of the bay model omitting wind stress. The developed model was then applied to foresee the sea-surface elevation associated with the catastrophic cyclone of 1991 and cyclone MORA. A comparative study of the water levels associated with a storm was made through model simulations with and without the inclusion of the river system. We found that the surge height in the bay-river junction area decreased by 20% and the surge height reduced by about 3-8% outside the junction area from this study. The obtained results were found to have a satisfactory similarity with some of the observed data.
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  • Landsat Thermal Infrared based Monitoring of Heat Losses from Kuju Fumaroles Area in Japan

    Mia, Md. Bodruddoza   Fujimitsu, Yasuhiro  

    The prime objective of our study was to monitor heat losses by using Landsat 7 thermal infrared data from the active fumarolic region of Kuju volcano in Japan. We estimated the radiative heat flux (RHF) of the Kuju fumaroles from 2002 to 2010, used the Stefan -Boltzmann equation. Then, heat discharge rate (HDR) was calculated by using the relationship coefficient of RHF and HDR, obtained from two previous studies. The highest total RHF was found about 57.7 MW in 2002 and lowest about 21.1 MW in 2010. The total RHF decreased from 2002 to 2007 about 33 MW; then, it slight increased about 5 MW in 2008 from 2007, and finally declined about 9MW from 2008 to 2010 in Kuju fumaroles. We found highest HDR about 384.5 MW in 2002 and lowest about 140.8 MW in 2010.The relationship between land surface temperature above ambient and RHF was an expected strong correlation for each result during our study period. RHF anomalous area showed a declining trend in overall during our study period. Overall, our study was able to delineate the decline trend of heat losses that was supported by the previous study of similar declining trend of HDR using steam maximum diameter method from active fumarolic region of Kuju volcano.
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  • Monitoring heat flow before and after eruption of Kuju fumaroles in 1995 using Landsat TIR images

    Mia, Md. Bodruddoza   Nishijima, Jun   Fujimitsu, Yasuhiro  

    The Kuju fumaroles in central Kyushu, Japan began to erupt as phreatic in nature on 11 October 1995. To infer the thermal activity, main objectives were to monitor the radiative heat flux (RHF) before and after eruption of Kuju fumaroles in 1995 using 4 sets of Landsat TM thermal infrared data from 1990 to 1996; and to calculate and monitor the heat discharge rate (HDR) after multiplying RHF using a relationship coefficient between RHF and HDR, derived from two previous studies. The RHF was estimated by using the Stefan–Boltzmann equation for heat flow where we applied satellite image-derived spectral emissivity and land surface temperature. An increasing trend of total radiant heat flux was obtained of about 22–39 MW before the Kuju fumaroles eruption from 1990 to 1994 and a declining trend total RHF of about 37–11 MW after eruption from 1995 to 1996. RHF was strongly correlated with land surface temperature (LST) above ambient in our study. Spatial distribution of RHF also showed a similar trend of total RHF. After using this relationship coefficient, we obtained the HDR from our study area about 144.64, 249.74, 239.67 and 68.54 MW in 1990, 1994, 1995 and 1996, respectively. The HDR was much higher before eruption in October 11, 1995 than that of after the eruption in our study. Fumaroles area also showed an abrupt increase of bared land and no vegetation just after eruption within the thematic map in 1995. Statistics of LST and RHF also showed evidences of heat loss activity before and after eruption in 1995. In conclusion, we infer from this study that Landsat TM thermal infrared images are fully competent to monitor thermal activity from any active volcano fumaroles for future eruption.
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  • Monitoring Thermal Activity of the Beppu Geothermal Area in Japan Using Multisource Satellite Thermal Infrared Data

    Mia, Md. Bodruddoza   Fujimitsu, Yasuhiro   Nishijima, Jun  

    The Beppu geothermal area, one of the largest spa resorts on the northeast Kyushu Island of Japan, is fed by hydrothermal fluids beneath the volcanic center of Mt. Garan and Mt. Tsurumi in the west. We explored the thermal status of the Beppu geothermal area using nighttime multisource satellite thermal infrared data (TIR) from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Landsat 8 thermal infrared scanner (TIRS) to monitor heat loss from 2009 to 2017. We also assessed heat loss from Mt. Garan fumaroles to investigate a relationship between them. The normalized differential vegetation index (NDVI) threshold method of spectral emissivity, the split-window algorithm for land surface temperature (LST), and the Stefan-Boltzmann equation for radiative heat flux (RHF) were used to estimate heat loss in this study. Total heat loss increased by about a 35% trend overall from 2009 to 2015 and then declined about 33-42% in 2017 in both the Beppu geothermal area and Mt. Garan fumaroles overall. The higher thermal anomalies were found in 2015 mostly in the southeastern coastal area of the Beppu geothermal region. The highest thermal anomaly was obtained in 2011 and the lowest in 2017 within the Mt. Garan fumaroles. The areas with a higher range of RHF values were recorded in 2015 in both study areas. Finally, the results show similar patterns of heat loss and thermal anomalies in both the Beppu geothermal area and Mt. Garan fumaroles, indicating a closely connected geothermal system overall. This suggests that nighttime TIR data are effective for monitoring the thermal status of the Beppu geothermal area.
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  • Monitoring heat losses using Landsat ETM plus thermal infrared data - a case study at Kuju fumarolic area in Japan

    Mia, Md. Bodruddoza   Fujimitsu, Yasuhiro  

    To monitor heat losses using Landsat 7 thermal infrared data from 2002 to 2010 within the active fumarolic region of Kuju volcano in Japan, we used the Stefan-Boltzmann equation for radiative heat flux (RHF) estimation. Heat discharge rate (HDR) was calculated by using the relationship coefficient of RHF and HDR, obtained from two previous studies. The highest total RHF was found to be about 57.7 MW in 2002 and the lowest was about 21.1 MW in 2010. We found the highest HDR, of about 384.5 MW, in 2002 and the lowest, of about 140.8 MW, in 2010. The RHF anomalous areas were showing a declining trend during our study period. The relationship between the land surface temperature (LST) above ambient and RHF was, as expected, in a strong correlation for each result during our study period. Overall, our study was able to delineate the declining trend of heat losses that supports a previous study of similar declining trend of HDR using steam maximum diameter method from the active fumarolic region of Kuju volcano.
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  • Monitoring Heat Losses Using Landsat ETM plus Thermal Infrared Data: a Case Study in Unzen Geothermal Field, Kyushu, Japan

    Mia, Md. Bodruddoza   Bromley, Chris J.   Fujimitsu, Yasuhiro  

    The Unzen geothermal field, our study area, is situated in the Shimabara Peninsula of Kyushu Island in Japan and is an area of active fumaroles.. Our prime objectives were (1) to estimate radiative heat flux (RHF), (2) to calculate approximately the heat discharge rate (HDR) using the relationship of RHF with the total heat loss derived from two geothermal field studies, and (3) finally, to monitor RHF as well as HDR in our study area using seven sets of Landsat 7 ETM + images from 2000 to 2009. We used the normalized differential vegetation index (NDVI) method for spectral emissivity estimation, the mono-window algorithm for land surface temperature (LST), and the Stefan-Boltzmann equation analyzing those satellite TIR images for RHF. We estimated that the maximum RHF was about 251 W/m(2) in 2005 and minimum was about 27 W/m(2) in 2001. The highest total RHF was about 39.1 MW in 2005 and lowest was about 12 MW in 2001 in our study region. We discovered that the estimated RHF was about 15.7 % of HDR from our studies. We applied this percentage to estimate HDR in Unzen geothermal area. The monitoring results showed a single fold trend of HDR from 2000 to 2009 with highest about 252 MW in 2005 and lowest about 78 MW in 2001. In conclusion, TIR remote sensing is thought as the best option for monitoring heat losses from fumaroles with high efficiency and low cost.
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  • Estimation and monitoring heat discharge rates using Landsat ETM+ thermal infrared data: a case study in Unzen geothermal field, Kyushu, Japan

    Mia, Md. Bodruddoza   Fujimitsu, Yasuhiro   Bromley, Chris J.  

    The Unzen geothermal field, our study area is active fumaroles, situated in Shimabara Peninsula of Kyushu Island in Japan. Our prime objectives were (1) to estimate radiative heat flux (RHF), (2) to calculate approximately heat discharge rate (HDR) using the relationship of radiative heat flux with the total heat loss derived from two geothermal field studies and (3) finally, to monitor RHF as well as HDR in our study area using seven sets of Landsat 7 ETM+ images from 2000 to 2009. We used the NDVI (Normalized differential vegetation index) method for spectral emissivity estimation, the mono-window algorithm for land surface temperature (LST) and the Stefan-Boltzmann equation analyzing those satellite TIR images for RHF. We obtained a desired strong correlation of LST above ambient with RHF using random samples. We estimated that the maximum RHF was about 251 W/m(2) in 2005 and minimum was about 27 W/m(2) in 2001. The highest total RHF was about 39.1 MW in 2005 and lowest was about 12 MW in 2001 in our study region. We discovered that the estimated RHF was about 15.7 % of HDR from our studies. We applied this percentage to estimate heat discharge rate in Unzen geothermal area. The monitoring results showed a single fold trend of HDR from 2000 to 2009 with highest about 252 MW in 2005 and lowest about 78 MW in 2001. In conclusion, TIR remote sensing is thought as the best option for monitoring heat losses from fumaroles with high efficiency and low cost.
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  • Thermal Activity Monitoring of an Active Volcano Using Landsat 8/OLI-TIRS Sensor Images:A Case Study at the Aso Volcanic Area in Southwest Japan

    Mia, Md. Bodruddoza   Fujimitsu, Yasuhiro   Nishijima, Jun  

    Thermal remote sensing is currently an emerging technique for monitoring active volcanoes around the world. The study area, the Aso volcano, is currently the most active and has erupted almost every year since 2012. For the first time, Landsat 8 TIRS thermal data were used in this study area to evaluate and monitor the recent thermal status of this volcano, situated in Southwest Japan, from 2013 to 2016 using four sets of images. The total heat discharged rate (HDR), radiative heat flux (RHF), land surface temperature (LST), and land cover (LC) were evaluated, and the relationship between them was determined, to understand the thermal status of the study area. We used the NDVI (normalized difference vegetation index) for land cover, the NDVI-threshold method for emissivity, the split-window algorithm for LST, and the Stefan-Boltzmann equation for radiative heat flux estimation in this study. The total heat discharge rate was computed using a relationship coefficient of RHF and HDR here. The highest HDR was obtained in 2013, at about 4715 MW, and was the lowest in 2016, at about 3819 MW. The total heat loss showed a declining trend, overall, from 2013 to 2016. The highest pixel RHF was in 2013 and the lowest was in 2014; after that, it increased gradually until 2016, coinciding with the LST of this study area. LC showed that, with decreasing heat loss, the vegetated coverage increased and bare land or mixed land decreased, and vice versa. From the spatial distribution of RHF, we saw that, within the Nakadake craters of the Aso volcano, Crater 1 was the most active part of this volcano throughout the study period, and Crater 3 was the most active after 2014. We inferred that the applied methods using the continuous Landsat 8 TIRS data showed an effective and efficient method of monitoring the thermal status of this active volcano.
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  • Monitoring heat flux using Landsat TM/ETM plus thermal infrared data - A case study at Karapiti ('Crater's of the Moon') thermal area, New Zealand

    Mia, Md. Bodruddoza   Bromley, Chris J.   Fujimitsu, Yasuhiro  

    Thermal infrared (TIR) data from available, daytime, Landsat-TM/ETM + satellite imagery, supported by ground measurements, were used in this study to investigate changes between 1990 and 2011 in the radiative component of the anomalous surface heat flux emitted from the 0.5 km(2) Karapiti thermal area, at Wairakei Geothermal Field, Taupo, New Zealand. The geothermal radiative heat flux (net RHF), of subsurface origin, was then assessed by subtracting the re-radiated heat flux that is of solar origin, as determined using coincident satellite imagery at two external sites. The total net RHF decreased by about 7 MW from 1990 to 2011. Results of a vegetation index study, using ratios of two (visible) spectral bands, implied that the area of healthy vegetation at Karapiti has progressively increased during this period. This supports the evidence for a decrease in geothermal heat flux, because the health of thermally-stressed vegetation is inversely related to shallow ground temperature. Although images of apparent land-surface temperature (LST) show large variations with time, this is attributable to ambient temperature change. Spot ground estimates of heat flux using a calorimeter also showed, on average, a decreasing trend of heat fluxes between 2000 and 2009, although several sites showed stable heat fluxes. Further supporting evidence came from repeated ground-based temperature-depth profiles, which showed that the near-surface boiling point depth lowered in levels at most sites between 2000 and 2011, although several sites located in actively-steaming bare-ground (similar to 98 degrees C at similar to 0.1 m depth) remained relatively stable. In conclusion, satellite imagery and supporting ground-based evidence suggest a pattern of gradual decline (despite some time and spatial variations) in overall heat fluxes over the past decade from the Karapiti thermal area. An analysis of satellite infrared data provides a useful and cost-effective option for monitoring of the total radiative component of surface heat-loss from relatively large areas of steaming ground, such as at Karapiti. (C) 2012 Elsevier B.V. All rights reserved.
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  • Closure to "Design method of time-dependent local scour at circular bridge pier" by Md. Faruque Mia and Hiroshi Nago

    Mia, MF   Nago, H  

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  • Closure to “Design Method of Time-Dependent Local Scour at Circular Bridge Pier” by Md. Faruque Mia and Hiroshi Nago

    Mia, Md. Faruque; Nago, Hiroshi  

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  • Closure to “Design Method of Time-Dependent Local Scour at Circular Bridge Pier” by Md. Faruque Mia and Hiroshi Nago

    Mia, Md. Faruque   Nago, Hiroshi  

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  • Discussion of “Design Method of Time-Dependent Local Scour at Circular Bridge Pier” by Md. Faruque Mia and Hiroshi Nago

    Oliveto, Giuseppe   Unger, Jens   Hager, Willi H.  

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  • Exploration of hydrothermal alteration and monitoring of thermal activity using multi-source satellite images:A case study of the recently active Kirishima volcano complex on Kyushu Island,Japan

    Mia, Md. Bodruddoza   Fujimitsu, Yasuhiro   Nishijima, Jun  

    Three major successive plinian or subplinian eruptions, following a long dormant period, occurred in January 2011, September 2017, and March 2018 within the Kirishima volcano complex on Kyushu Island, Japan. Herein, we applied a Landsat 8 image to explore the most active hydrothermal altered area of the Kirishima volcano complex, and nine sets of nighttime ASTER thermal infrared data to explore changes of heat loss to the thermally active area of the Shinmoedake and Ohnamiike craters within this volcanic complex from 2009 to 2018. Color composite, band ratio, principal component analysis, and Crosta techniques were used to map hydrothermal alteration. Meanwhile, the normalized difference vegetation index threshold method for emissivity retrieval, the split-window algorithm for land surface temperature (LST), and the Stefan-Boltzmann equation were used to derive the radiative heat flux (RHF) for the study area. Total radiative heat loss (RHL) in megawatts was calculated by adding pixels positive RHF (W/m(2)) values after multiplying with the pixel area. Using these data, the spatial distribution of altered mineral zones was mapped for the Kirishima volcano complex. We estimated that the maximum LSTs above ambient values were about 24 degrees C, 12 degrees C, and 12 degrees C, immediately following the 2011, 2017 and 2018 eruptions. Highest pixel RHFs of 136 W/m(2), 75 W/m(2), and 61 W/m(2) were also measured just after these eruptions, on 15 November 2011, 30 October 2017, and 8 April 2018, producing peaks in the total RHL of 233 MW, 198 MW and 101 MW, respectively. The Shinmoedake crater had more intense thermal activity than the Ohnamiike crater after both the 2011 and 2018 eruptions but had less intense activity after the 2017 eruption. The intensity of thermal unrest decreased during the study period from both craters. This study illustrates how Landsat TIRS/OLI data can be used for hydrothermal alteration as well as nighttime ASTER thermal infrared data to monitor effectively the thermal activity of active areas of the Kirishima volcano complex.
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