Currently, I am a JSPS postdoctoral researcher in Kyushu University of Japan. I am an Associate Professor of Geology Department of Dhaka University in Bangladesh. I am working in the field of Remote sensing in Geosciences field. Phone: +8801818240937 Address: Department of Geology, University of Dhaka, Dhaka, 1000, Bangladesh
ABSTRACT he Unzen geothermal field, our study area is active fumaroles, situated in Shimabara Pen... more ABSTRACT he 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/m2 in 2005 and minimum was about 27 W/m2 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. (auth)
The prime objective of our study was to monitor heat losses by using Landsat 7 thermal infrared d... more 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.
The Unzen geothermal field, our study area, is situated in the Shimabara Peninsula of Kyushu Isla... more 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/m2 in 2005 and minimum was about 27 W/m2 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.
To monitor heat losses using Landsat 7 thermal infrared data from 2002 to 2010 within the active ... more 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.
To evaluate the conventional methods for mapping hydrothermal altered deposits by using Landsat 7... more To evaluate the conventional methods for mapping hydrothermal altered deposits by using Landsat 7 ETM+ image in and around Kuju volcano is the prime target of our study. The Kuju volcano is a mountainous composite which consists of hornblende-andesite lava domes and associated lava flows. We used the colour composite, band ratio, principal component analysis, least square fitting and reference spectra analysis methods. The colour composite and band ratio methods showed very clearly the hydrothermal altered deposits of clay minerals, iron oxides and ferric oxides around the fumaroles. The principal component analysis using the Crosta technique also enabled us to represent undoubtedly the altered hydroxyl and iron-oxide mineral deposits of this region concentrating around the fumaroles. Least square fitting method illustrated the goethite, hematite and clay alteration region. Finally the target detection method for reference spectral analysis by using ENVI 4.3 detected the representative hydrothermal altered minerals around Kuju volcano fumaroles area. Therefore, all the methods showed high efficiency for mapping hydrothermal altered deposits especially iron-oxide minerals such as hematite, goethite and jarosite, which are alteration products of hydrothermal sulfides around the fumaroles.
Journal of Volcanology and Geothermal Research, 2012
Thermal infrared (TIR) data from available, daytime, Landsat-TM/ETM + satellite imagery, supporte... more 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 km2 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 (~ 98 °C at ~ 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.► Total radiative heat flux has reduced about 11 MW from 2000 to 2011. ► Net radiative heat flux showed a gradual decline of about 7 MW from 1990 to 2011. ► To increase vegetated area is a consequence of decreasing net radiative heat flux. ► Repeated ground-based total heat fluxes, at most sites, showed a declining trend. ► Levels of the boiling point depth in the soil were reduced between 2000 and 2010.
The lithologic composition and grain size distribution of sediments are primary determinants of t... more The lithologic composition and grain size distribution of sediments are primary determinants of their inherent reflectance properties. However, moisture content is also known to have a strong influence on reflectances of soils and sediments. If the effects of sediment composition, grain size and moisture content could be distinguished spectrally, it might be possible to map these properties at synoptic scales using hyperspectral, or perhaps even broadband, remote sensing. Mapping the spatiotemporal distribution of sediment composition and moisture content could provide unique constraints on both the processes by which the sediments are deposited as well as the constraints they may impose on subsequent water flow and sediment transport. The Ganges–Brahmaputra delta (GBD) is formed by the convergence of these two great rivers and is superlative in both size and geologic activity. Sediment redistribution and channel migration associated with the annual floods disrupt the lives of hundreds of thousands of people living on the GBD but is also critical for maintaining the delta area fertile and above sea level. The 30+ year archive of Landsat imagery could provide a basis for spatiotemporal analysis of these fluvial dynamics if sediment properties could be inferred or measured from reflectance spectra. However, before confronting the challenge of broadband detection we must understand the spectral properties of the sediments under more controlled laboratory conditions. Bidirectional reflectance spectroscopy of 109 sediment samples from the GBD yields a spectral mixing space that appears to be structured by variations in moisture content, grain size and possibly lithology. Although the individual Empirical Orthogonal Functions of the Principal Components do not correspond to unique absorption features, clustering within the mixing space is clearly influenced by moisture content and grain size. Laboratory spectra of sediment reflectance measured under varying moisture content yield distinct trajectories through the spectral mixing space for different grain size distributions of sieved sediments. These variations in moisture content account for > 98% of spectral variance observed in these samples. Drying trajectories of coarse, fine and mixed sediments are distinct and suggest that moisture and grain size might be spectrally distinguishable. These results are consistent with Angstrom's hypothesis of moisture-driven spectral absorption but more controlled experiments are necessary to test the hypothesis rigorously.
ABSTRACT he Unzen geothermal field, our study area is active fumaroles, situated in Shimabara Pen... more ABSTRACT he 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/m2 in 2005 and minimum was about 27 W/m2 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. (auth)
The prime objective of our study was to monitor heat losses by using Landsat 7 thermal infrared d... more 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.
The Unzen geothermal field, our study area, is situated in the Shimabara Peninsula of Kyushu Isla... more 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/m2 in 2005 and minimum was about 27 W/m2 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.
To monitor heat losses using Landsat 7 thermal infrared data from 2002 to 2010 within the active ... more 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.
To evaluate the conventional methods for mapping hydrothermal altered deposits by using Landsat 7... more To evaluate the conventional methods for mapping hydrothermal altered deposits by using Landsat 7 ETM+ image in and around Kuju volcano is the prime target of our study. The Kuju volcano is a mountainous composite which consists of hornblende-andesite lava domes and associated lava flows. We used the colour composite, band ratio, principal component analysis, least square fitting and reference spectra analysis methods. The colour composite and band ratio methods showed very clearly the hydrothermal altered deposits of clay minerals, iron oxides and ferric oxides around the fumaroles. The principal component analysis using the Crosta technique also enabled us to represent undoubtedly the altered hydroxyl and iron-oxide mineral deposits of this region concentrating around the fumaroles. Least square fitting method illustrated the goethite, hematite and clay alteration region. Finally the target detection method for reference spectral analysis by using ENVI 4.3 detected the representative hydrothermal altered minerals around Kuju volcano fumaroles area. Therefore, all the methods showed high efficiency for mapping hydrothermal altered deposits especially iron-oxide minerals such as hematite, goethite and jarosite, which are alteration products of hydrothermal sulfides around the fumaroles.
Journal of Volcanology and Geothermal Research, 2012
Thermal infrared (TIR) data from available, daytime, Landsat-TM/ETM + satellite imagery, supporte... more 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 km2 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 (~ 98 °C at ~ 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.► Total radiative heat flux has reduced about 11 MW from 2000 to 2011. ► Net radiative heat flux showed a gradual decline of about 7 MW from 1990 to 2011. ► To increase vegetated area is a consequence of decreasing net radiative heat flux. ► Repeated ground-based total heat fluxes, at most sites, showed a declining trend. ► Levels of the boiling point depth in the soil were reduced between 2000 and 2010.
The lithologic composition and grain size distribution of sediments are primary determinants of t... more The lithologic composition and grain size distribution of sediments are primary determinants of their inherent reflectance properties. However, moisture content is also known to have a strong influence on reflectances of soils and sediments. If the effects of sediment composition, grain size and moisture content could be distinguished spectrally, it might be possible to map these properties at synoptic scales using hyperspectral, or perhaps even broadband, remote sensing. Mapping the spatiotemporal distribution of sediment composition and moisture content could provide unique constraints on both the processes by which the sediments are deposited as well as the constraints they may impose on subsequent water flow and sediment transport. The Ganges–Brahmaputra delta (GBD) is formed by the convergence of these two great rivers and is superlative in both size and geologic activity. Sediment redistribution and channel migration associated with the annual floods disrupt the lives of hundreds of thousands of people living on the GBD but is also critical for maintaining the delta area fertile and above sea level. The 30+ year archive of Landsat imagery could provide a basis for spatiotemporal analysis of these fluvial dynamics if sediment properties could be inferred or measured from reflectance spectra. However, before confronting the challenge of broadband detection we must understand the spectral properties of the sediments under more controlled laboratory conditions. Bidirectional reflectance spectroscopy of 109 sediment samples from the GBD yields a spectral mixing space that appears to be structured by variations in moisture content, grain size and possibly lithology. Although the individual Empirical Orthogonal Functions of the Principal Components do not correspond to unique absorption features, clustering within the mixing space is clearly influenced by moisture content and grain size. Laboratory spectra of sediment reflectance measured under varying moisture content yield distinct trajectories through the spectral mixing space for different grain size distributions of sieved sediments. These variations in moisture content account for > 98% of spectral variance observed in these samples. Drying trajectories of coarse, fine and mixed sediments are distinct and suggest that moisture and grain size might be spectrally distinguishable. These results are consistent with Angstrom's hypothesis of moisture-driven spectral absorption but more controlled experiments are necessary to test the hypothesis rigorously.
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Papers by Md. Bodruddoza Mia