scholarly journals Application of ASTER Data for Differentiating Carbonate Minerals and Evaluating MgO Content of Magnesite in the Jiao-Liao-Ji Belt, North China Craton

2022 ◽  
Vol 14 (1) ◽  
pp. 181
Author(s):  
Young-Sun Son ◽  
Gilljae Lee ◽  
Bum Han Lee ◽  
Namhoon Kim ◽  
Sang-Mo Koh ◽  
...  
Keyword(s):  
North China ◽  
Thermal Emission ◽  
Regional Scale ◽  
Oxide Content ◽  
Carbonate Minerals ◽  
Band Ratio ◽  
Band Ratios ◽  
Relative Absorption ◽  
Grade Assessment ◽  
Shortwave Infrared

Numerous reports have successfully detected or differentiated carbonate minerals such as calcite and dolomite by using the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). However, there is a need to determine whether existing methods can differentiate magnesite from other carbonate minerals. This study proposes optimal band ratio combinations and new thresholds to distinguish magnesite, dolomite, and calcite using ASTER shortwave-infrared (SWIR) data. These were determined based on the spectral and chemical analysis of rock samples collected from Liaoning, China and Danchon, North Korea and the reflectance values from ASTER images. The results demonstrated that the simultaneous use of thresholds 2.13 and 2.015 for relative absorption band depths (RBDs) of (6 + 8)/7 and (7 + 9)/8, respectively, was the most effective for magnesite differentiation. The use of RBDs and band ratios to discriminate between dolomite and calcite was sufficiently effective. However, talc, tremolite, clay, and their mixtures with dolomite and calcite, which are commonly found in the study area, hampered the classification. The assessment of the ASTER band ratios for magnesite grade according to magnesium oxide content indicated that a band ratio of 5/6 was the most effective for this purpose. Therefore, this study proved that ASTER SWIR data can be effectively utilized for the identification and grade assessment of magnesite on a regional scale.

scholarly journals Assessment of multispectral glacier mapping methods and derivation of glacier area changes, 1978–2002, in the central Southern Alps, New Zealand, from ASTER satellite data, field survey and existing inventory data

2011 ◽  
Vol 57 (204) ◽  
pp. 667-683 ◽  
Author(s):  
E.F. Gjermundsen ◽  
R. Mathieu ◽  
A. Kääb ◽  
T. Chinn ◽  
B. Fitzharris ◽  
...  
Keyword(s):  
New Zealand ◽  
Thermal Emission ◽  
Southern Alps ◽  
Aerial Photographs ◽  
Glacier Area ◽  
Automated Classification ◽  
Classification Methods ◽  
Band Ratio ◽  
Glacier Inventory ◽  
Normalized Difference Snow Index

AbstractWe have measured the glacier area changes in the central Southern Alps, New Zealand, between 1978 and 2002 and have compiled the 2002 glacier outlines using an image scene from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). Three automated classification methods were tested: (1) band ratio, (2) normalized-difference snow index and (3) supervised classification. The results were compared with the glacier outlines photo-interpreted from the ASTER data, and were further validated using GPS-aided field mapping of selected test glaciers. The ASTER 3/4 band ratio provided the best results. However, all the classification methods failed to extract extensive debris-covered parts of the glaciers. Therefore, the photo-interpreted 2002 outlines were used when comparing with the existing 1978 glacier inventory derived from aerial photographs. Our results show a ∼17% reduction of glacier area, mainly driven by the retreat of the large valley glaciers. Despite the large climatic gradient from west to east, glaciers on both sides of the Main Divide lost similar percentages of area, except Franz Josef and Fox Glaciers which advanced. Smaller glaciers were found to have changed very little in the study period.

scholarly journals Simulated Multispectral Temperature and Atmospheric Composition Retrievals for the JPL GEO-IR Sounder

2021 ◽  
Author(s):  
Vijay Natraj ◽  
Ming Luo ◽  
Jean-Francois Blavier ◽  
Vivienne H. Payne ◽  
Derek J. Posselt ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Thermal Emission ◽  
Weather Forecasting ◽  
Lower Troposphere ◽  
Atmospheric Temperature ◽  
Atmospheric Composition ◽  
Near Surface ◽  
Infrared Measurements ◽  
Infrared Spectral ◽  
Shortwave Infrared

Abstract. Satellite measurements enable quantification of atmospheric temperature, humidity, and trace gas vertical profiles. The majority of current instruments operate on polar orbiting satellites and either in the thermal/mid-wave or in the shortwave infrared spectral regions. We present a new multispectral instrument concept for improved measurements from geostationary orbit (GEO) with sensitivity to the boundary layer. The JPL GEO-IR sounder, which is an imaging Fourier Transform Spectrometer, uses a wide spectral range (1–15.4 μm), encompassing both reflected solar and thermal emission bands to improve sensitivity to the lower troposphere and boundary layer. We perform retrieval simulations for both clean and polluted scenarios that also encompass different temperature and humidity profiles. The results illustrate the benefits of combining shortwave and thermal infrared measurements. In particular, the former adds information in the boundary layer, while the latter helps to separate near-surface and mid-tropospheric variability. The performance of the JPL GEO-IR sounder is similar to or better than currently operational instruments. The proposed concept is expected to improve weather forecasting, severe storm tracking and forecasting, and also benefit local and global air quality and climate research.

scholarly journals CHROMITITE PROSPECTING USING LANDSAT TM AND ASTER REMOTE SENSING DATA

2015 ◽  
Vol II-2/W2 ◽  
pp. 99-103 ◽  
Author(s):  
A. Beiranvand Pour ◽  
M. Hashim ◽  
M. Pournamdari
Keyword(s):  
Remote Sensing ◽  
Satellite Data ◽  
Host Rock ◽  
Regional Scale ◽  
High Potential ◽  
Landsat Tm ◽  
Band Ratio ◽  
Spectral Angle Mapper ◽  
Spectral Transform ◽  
Ophiolitic Rock

Studying the ophiolite complexes using multispectral remote sensing satellite data are interesting because of high diversity of minerals and the source of podiform chromitites. This research developed an approach to discriminate lithological units and detecting host rock of chromitite bodies within ophiolitic complexes using the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Landsat Thematic Mapper (TM) satellite data. Three main ophiolite complexes located in south of Iran have been selected for the study. Spectral transform techniques, including minimum noise fraction (MNF) and specialized band ratio were employed to detect different rock units and the identification of high-potential areas of chromite ore deposits within ophiolitic complexes. A specialized band ratio (4/1, 4/5, 4/7) of ASTER, MNF components and Spectral Angle Mapper (SAM) on ASTER and Landsat TM data were used to distinguish ophiolitic rock units. Results show that the specialized band ratio was able to identify different rock units and serpentinized dunite as host rock of chromitites within ophiolitic complexes, appropriately. MNF components of ASTER and Landsat TM data were suitable to distinguish ophiolitic rock complexes at a regional scale. The integration of SAM and Feature Level Fusion (FLF) used in this investigation discriminated the ophiolitic rock units and prepared detailed geological map for the study area. Accordingly, high potential areas (serpentinite dunite) were identified in the study area for chromite exploration targets.The approach used in this research offers the image processing techniques as a robust, reliable, fast and cost-effective method for detecting serpentinized dunite as host rock of chromitite bodies within vast ophiolite complexes using ASTER and Landsat TM satellite data.

scholarly journals Extreme droughts/floods and their impacts on harvest derived from historical documents in Eastern China during 801–1910

2019 ◽  
Author(s):  
Zhixin Hao ◽  
Maowei Wu ◽  
Jingyun Zheng ◽  
Jiewei Chen ◽  
Xuezhen Zhang ◽  
...  
Keyword(s):  
North China ◽  
Eastern China ◽  
Regional Scale ◽  
Extreme Drought ◽  
Historical Documents ◽  
Warm Climate ◽  
Extreme Flood ◽  
Historical Times ◽  
The Impact

Abstract. Chinese historical documents recorded plenty of information related with climate change and grain harvest, which are helpful to explore the impacts of extreme drought/flood on crops and the implications on adaptation for agriculture to more extreme climate probability in the context of global warming. Here, we used the reconstructed extreme drought/flood chronologies and reconstructed grain harvest series derived from historical documents to investigate the connection between the occurrences of extreme drought/flood in eastern China and poor harvest during 801–1910. The results showed that more extreme droughts occurred in 801–870, 1031–1230, 1481–1530 and 1581–1650 over whole eastern China. On regional scale, more extreme droughts occurred in 1031–1100, 1441–1490, 1601–1650 and 1831–1880 in North China, 801–870, 1031–1120, 1161–1220 and 1471–1530 in Jianghuai, 991–1040, 1091–1150, 1171–1230, 1411–1470 and 1481–1530 in Jiangnan. The grain harvest was poor in periods of 801–940, 1251–1650 and 1841 to 1910, but bumper in periods of 951–1250 and 1651–1840 approximately. For entire period of 801–1910, more occurrence of extreme drought in any sub–region of eastern China could significantly reduce harvest in the long term average, but the connection between harvest and extreme flood seemed to be much weaker. The co–occurrence of extreme drought and extreme flood in different sub–regions in the same year had a greater impact on harvest yield. However, the connection between the occurrence of poor harvest and regional extreme drought was weak in the warm epoch of 920–1300 but strong in the cold epoch of 1310–1880, which implicated warm climate might weaken the impact of extreme drought on poor harvest during historical times.

scholarly journals APPLICATION OF WORLDVIEW-3 DATA IN ALTERATION MINERAL MAPPING IN CHADORMALU AREA, CENTRAL IRAN

2019 ◽  
Vol XLII-4/W18 ◽  
pp. 589-596
Author(s):  
Z. Karimzadeh ◽  
M. H. Tangestani
Keyword(s):  
Large Scale ◽  
Iron Ore ◽  
Central Iran ◽  
Iron Deposit ◽  
Absorption Feature ◽  
Spectral Absorption ◽  
Band Ratio ◽  
Band Ratios ◽  
Alteration Minerals ◽  
Absorption Features

Abstract. WorldView-3 (WV-3), launched in August 2014, is a commercial imaging satellite with high spatial resolution that measures reflected radiation in VNIR-SWIR regions in 16 bands. The main objective of this study was to discriminate the alteration minerals in Chadormalu iron deposit area, central Iran, using band ratio techniques on the selected bands of this satellite. To identify the appropriate band ratios the spectral bands of WV-3 were investigated and assessed. Regarding to Fe3+, Fe2+, Al-OH, Fe-OH, Mg-OH and CO32− spectral absorption features, band ratios B5/B2, B13/B9, B13/B14 and B14/B16 were proposed for enhancement of ferrous and ferric iron bearing minerals, sericite, epidote, chlorite, and dolomite. Combination of field observations, geological map and high resolution spectra of rock samples were used to verify the results. Band ratio B5/B2, B13/B9, B13/B14 gray scale images respectively illustrated that Fe3+-rich minerals are occurring in granite, the Fe2+-rich minerals are enhanced in iron ore, green schist, and diorite units, and sericite is occurring in hydrothermally altered granite and iron ore. Since the Fe/Mg-OH vibrational mode in chlorite-epidote and spectral absorption feature of CO32− in dolomite occur in B16, the B14/B16 ratio highlighted chlorite-epidote-rich green schist, diorite and dolomitic marble. The false color composite image of B13/B14, B13/B9, and B14/B16 as RGB produced a large scale map which successfully discriminated the rock types and accompanying alteration minerals. This study demonstrated that WV-3 data have efficient spectral resolution to discriminate alteration minerals with Fe3+, Fe2+, Al-OH and Fe/Mg-OH or CO32− spectral absorption features.

scholarly journals A new satellite-derived glacier inventory for western Alaska

2011 ◽  
Vol 52 (59) ◽  
pp. 135-143 ◽  
Author(s):  
R. Le Bris ◽  
F. Paul ◽  
H. Frey ◽  
T. Bolch
Keyword(s):  
Line Graph ◽  
Strong Dependence ◽  
Regional Scale ◽  
Band Ratio ◽  
Kenai Peninsula ◽  
Glacier Inventory ◽  
The Us ◽  
Change Impact ◽  
Mapping Techniques ◽  
Global Sea Level

AbstractGlacier inventories provide the baseline data to perform climate-change impact assessment on a regional scale in a consistent and spatially representative manner. In particular, a more accurate calculation of the current and future contribution to global sea-level rise from heavily glacierized regions such as Alaska is much needed. We present a new glacier inventory for a large part of western Alaska (including Kenai Peninsula and the Tordrillo, Chigmit and Chugach mountains), derived from nine Landsat Thematic Mapper scenes acquired between 2005 and 2009 using well-established automated glacier-mapping techniques (band ratio). Because many glaciers are covered by optically thick debris or volcanic ash and partly calve intowater, outlineswere manually edited in these wrongly classified regions during post-processing. In total we mapped ~8830 glaciers (>0.02 km2) with a total area of ~16 250 km2. Large parts of the area (47%) are covered by a few (31) large (>100 km2) glaciers, while glaciers less than 1 km2 constitute only 7.5% of the total area but 86% of the total number. We found a strong dependence of mean glacier elevation on distance from the ocean and only a weak one on aspect. Glacier area changes were calculated for a subset of 347 selected glaciers by comparison with the Digital Line Graph outlines from the US Geological Survey. The overall shrinkage was ~23% between 1948–57 and 2005–09.

Crustal heat generation rates in the North China Khondalite Belt high to ultra-high-temperature metamorphic rock system

2020 ◽  
Author(s):  
Xiaofang He ◽  
Martin Hand ◽  
Derrick Hasterok
Keyword(s):  
High Temperature ◽  
Heat Generation ◽  
North China ◽  
Regional Scale ◽  
Rock System ◽  
The North ◽  
Uht Metamorphism ◽  
Thermal Sources ◽  
Khondalite Belt

<p>The widespread occurrence of high to ultra-high temperature (HT-UHT) metamorphism in continental crust has been widely documented worldwide. However, there has been ongoing debate on the heat sources responsible for generating these HT-UHT conditions.</p><p> </p><p>Generating HT-UHT temperatures is thought to require either singularly, or in combination, long-lived crustal thickening (e.g. orogenic systems) with high radioactive heat production and low erosion rates, or large supplies of heat from the mantle either through conduction within thinned lithosphere (e.g. back-arc) or by advective heating linked to large-scale mantle-derived  magma’s. Distinction between these two major thermal sources can made on the crustal heat generation rates and timescales of the HT-UHT metamorphism and the volumes of externally derived high-temperatures magmas. Therefore, a detailed understanding of the terrain-scale heat generation rates, and the metamorphic P-T-­t path inferred from the integration of petrochronology and phase equilibria modelling can provide important information.</p><p> </p><p>The Paleoproterozoic Khondalite (metasedimentary) rock system in the North China Craton is thought to represent a typical Paleoproterozoic HT metamorphic belt with local areas reaching UHT conditions and it has been extensively studied. In terms of the thermal drivers, most workers suggest advective heating from the emplacement of mantle related mafic magma, although the apparent volume of clearly-mantle derived magma appears generally insufficient to account for the regional extent of HT-UHT conditions.</p><p> </p><p>To better understand the mechanisms leading the HT-UHT conditions, we need (1) regional-scale measurements of in-situ heat producing elements and (2) a better understanding of the duration of HT-UHT conditions on a regional scale. To better characterise in-situ thermal sources we have determined heat generation rates using quantitative in-field gamma ray spectrometer (GRS) analysis. Volume averaging of rock types indicates terrain-scale U-Th concentrations would have generated around 3mWm<sup>-3</sup> at the time of metamorphism.  Given that U-Th would have been lost from the metamorphic system during extraction of high-temperature crustal melts, simple modelling shows the crustal U-Th concentrations would have contributed substantially to the generation of the high-temperature thermal regime. Furthermore, a preliminary compilation of concordant zircon and monazite metamorphic ages from published literature shows a range of ca. 1950-1850 Ma in both western and eastern Khondalite Belt, suggesting possible long-lived metamorphism. Therefore, we argue that the role of the mantle derived advective heat in generating the UHT regime in the North China Khondalite Belt may have been overestimated.</p><p> </p><p><strong>Key words: </strong>heat generation, HT-UHT metamorphism, Khondalite Belt, North China Craton</p>

scholarly journals HDO/H<sub>2</sub>O ratio retrievals from GOSAT

2013 ◽  
Vol 6 (3) ◽  
pp. 599-612 ◽  
Author(s):  
H. Boesch ◽  
N. M. Deutscher ◽  
T. Warneke ◽  
K. Byckling ◽  
A. J. Cogan ◽  
...  
Keyword(s):  
Zenith Angle ◽  
Solar Zenith Angle ◽  
A Priori ◽  
Regional Scale ◽  
Atmospheric Temperature ◽  
Total Carbon ◽  
Latitudinal Gradients ◽  
Random Errors ◽  
Synthetic Simulation ◽  
Shortwave Infrared

Abstract. We report a new shortwave infrared (SWIR) retrieval of the column-averaged HDO/H2O ratio from the Japanese Greenhouse Gases Observing Satellite (GOSAT). From synthetic simulation studies, we have estimated that the inferred δD values will typically have random errors between 20‰ (desert surface and 30° solar zenith angle) and 120‰ (conifer surface and 60° solar zenith angle). We find that the retrieval will have a small but significant sensitivity to the presence of cirrus clouds, the HDO a priori profile shape and atmospheric temperature, which has the potential of introducing some regional-scale biases in the retrieval. From comparisons to ground-based column observations from the Total Carbon Column Observing Network (TCCON), we find differences between δD from GOSAT and TCCON of around −30‰ for northern hemispheric sites which increase up to −70‰ for Australian sites. The bias for the Australian sites significantly reduces when decreasing the spatial co-location criteria, which shows that spatial averaging contributes to the observed differences over Australia. The GOSAT retrievals allow mapping the global distribution of δD and its variations with season, and we find in our global GOSAT retrievals the expected strong latitudinal gradients with significant enhancements over the tropics. The comparisons to the ground-based TCCON network and the results of the global retrieval are very encouraging, and they show that δD retrieved from GOSAT should be a useful product that can be used to complement datasets from thermal-infrared sounder and ground-based networks and to extend the δD dataset from SWIR retrievals established from the recently ended SCIAMACHY mission.

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