Higher Reflectance Values Research Articles

An inverse method to retrieve 3D radar reflectivity composites

Summary Dense radar networks offer the possibility of getting better Quantitative Precipitation Estimates (QPE) than those obtained with individual radars, as they allow increasing the coverage and improving quality of rainfall estimates in overlapping areas. Well-known sources of error such as attenuation by intense rainfall or errors associated with range can be mitigated through radar composites. Many compositing techniques are devoted to operational uses and do not exploit all the information that the network is providing. In this work an inverse method to obtain high-resolution radar reflectivity composites is presented. The method uses a model of radar sampling of the atmosphere that accounts for path attenuation and radar measurement geometry. Two significantly different rainfall situations are used to show detailed results of the proposed inverse method in comparison to other existing methodologies. A quantitative evaluation is carried out in a 12 h-event using two independent sources of information: a radar not involved in the composition process and a raingauge network. The proposed inverse method shows better performance in retrieving high reflectivity values and reproducing variability at convective scales than existing methods.

Production of HfO2 thin films using different methods: chemical bath deposition, SILAR and sol-gel process

Hafnium oxide thin films (HOTFs) were successfully deposited onto amorphous glasses using chemical bath deposition, succes- sive ionic layer absorption and reaction (SILAR), and sol-gel methods. The same reactive precursors were used for all of the methods, and all of the films were annealed at 300°C in an oven (ambient conditions). After this step, the optical and structural properties of the films pro- duced by using the three different methods were compared. The structures of the films were analyzed by X-ray diffraction (XRD). The opti- cal properties are investigated using the ultraviolet-visible (UV-VIS) spectroscopic technique. The film thickness was measured via atomic force microscopy (AFM) in the tapping mode. The surface properties and elemental ratios of the films were investigated and measured by scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDX). The lowest transmittance and the highest reflectance values were observed for the films produced using the SILAR method. In addition, the most intense characteristic XRD peak was observed in the diffraction pattern of the film produced using the SILAR method, and the greatest thickness and average grain size were calculated for the film produced using the SILAR method. The films produced using SILAR method contained fewer cracks than those produced using the other methods. In conclusion, the SILAR method was observed to be the best method for the production of HOTFs.

Characterizing background heterogeneity in visual communication

How is a visual signal effectively transmitted through an environment triggering a response by a perceiver? Experimental and theoretical works in disparate fields, such as sexual selection and plant–animal interactions, have demonstrated selection based on signal conspicuousness. However, to properly describe the conspicuousness of a signal, it is necessary to quantify the spatial and temporal heterogeneity of background coloration of a signaler. We intend to compare the effectiveness of four methods developed to characterize background heterogeneity. To describe the background in a seasonal vegetation, we collected reflectance data in dry and wet seasons of (i) target leaves (those leaves against which a signal is predominantly displayed); (ii) overall leaves (leaves from the most common plant species in the community); (iii) frames in a limited area in space, by measuring the reflectance of all material found in the background; and (iv) background items from the most common species, based on their abundance along transects. We analyzed seasonal color changes in terms of hue, chroma and brightness and described the conspicuousness of fruit coloration according to avian vision. All methods found significant differences in the background coloration between seasons, with higher reflectance values in the dry season. Hue values were higher in the dry season, and chroma values were higher in the wet season. Only the methods most restricted in space (target leaves and frames) recorded seasonal differences in fruit conspicuousness. The transects and frames methods are useful for describing the backgrounds of non-stationary signals (i.e., those of most animals). For plant signals, which are displayed against a fixed background in space, we recommend specific sampling of target leaves. Our results support the importance of measuring the seasonal heterogeneity of the background but also indicate that a monthly sampling design is not necessary to evaluate the conspicuousness of fruit signals.

Fs Laser surface nano-structuring of high refractory ceramics to enhance solar radiation absorbance

High refractory pressure-less sintered ternary composite ceramics of AlN-SiC-MoSi2 (ASMY), polished by mechanical grinding to a surface roughness R a ~40 nm, have been treated in vacuum by fs Ti:sapphire laser, operating at 800 nm wavelength, 100 fs pulse duration, and increasing fluence, to generate a “black ceramic material”, able to minimize solar radiation reflectance, in such a way that they could be used as the absorber material in an innovative conversion module of solar radiation into electrical energy. Disk specimens of approximately 3 cm in diameter and 3 mm thick have been treated by normal incident laser beam, generating a scanning pattern of parallel lines, at a lateral distance of about 80 μm, using a stage in motion, in the x, y, z directions, driven by a computer. The experimental conditions of laser treatment (energy fluence, speed of transition and lateral distance of steps) have been optimized to maximize the absorption properties of the patterned surface. In some samples this value was increased by about 15 %, compared to untreated surface, up to a value of final absorbance of about 95 %, all over the range of solar radiation spectrum (from UV to NIR). The morphological and chemical effects have been evaluated by SEM–EDS analysis. At higher fluence, we obtained the characteristic ablation craters and corresponding local material decomposition, while at lower fluence (over the ablation threshold) an ordered periodic nano-structure has been obtained, exploitable for its high capacity of entrapment of visible light. The laser treated ceramic specimen, characterized by very high absorption properties and reflectivity values lower than 4 %, has been used as active absorber material in a conversion module, installed in a solar test platform.

Uso de imagens MODIS no monitoramento do fluxo de sedimentos no reservatório de Três Marias

Objetivou-se, neste trabalho, monitorar o fluxo de entrada de sedimentos no braço do Rio Indaiá no reservatório de Três Marias, MG, com base em dados das imagens de satélites. Foram adquiridas séries temporais de 12 anos das imagens MODIS (Terra e Aqua), compostas de 8 dias. Estimativas de reflectância da superfície foram calculadas usando-se o algoritmo MOD3R. Dados hidrossedimentométricos da estação de monitoramento do Rio Indaiá foram integrados às análises para se entender a relação entre as respostas das imagens de satélites e as medições de campo. Os resultados apontaram uma forte relação entre os dados de reflectância e a descarga sólida calculada no Rio Indaiá; há, também, uma forte variação da reflectância ao longo do braço do reservatório no sentido da montante à jusante, com altos valores de reflectância à montante e valores baixos à jusante. O percentual de registros válidos estimados nas imagens MODIS atendeu aos requisitos de monitoramento do fluxo de sedimentos enquanto as estimativas de reflectância da água mostraram grande potencial em relacionar as respostas espectrais das imagens de satélites com a variação da descarga sólida de sedimento no braço do Rio Indaiá.

Time efficient texturization of multicrystalline silicon in the HF/HNO3 solutions and its effect on optoelectronic parameters of solar cells

In this paper the improving photovoltaic conversion efficiency of multicrystalline silicon solar cells obtained by acid texturization is presented. Different solutions from two various composition ranges of HF:HNO3:CH3COOH/H2O system were examined. The influence of the HF/HNO3 content, type of diluents and texturization process time on the basic optoelectronic parameters of multicrystalline solar cells was also studied. This research brings new experimental receipt which allows to obtain the proper surface morphology after the texturization in a very short time of 60s. The optimal acid volume etching ratio was found to be HF:HNO3:H2O=7:1:2. For the first time, etching lasting 1min causes the lowering the reflectivity value below 12% and also improves the conversion efficiency by 22% in relation to the reference sample without acid texture. The inverse HF/HNO3 ratio resulted in two times higher diameter of obtained rounded pits which allowed better coverage of the front metal grid patterning over the flat surface. Moreover, the higher reflectance value was accompanied by relatively high efficiency up to 13.9%.

Global inventory and characterization of pyroclastic deposits on Mercury: New insights into pyroclastic activity from MESSENGER orbital data

AbstractWe present new observations of pyroclastic deposits on the surface of Mercury from data acquired during the orbital phase of the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission. The global analysis of pyroclastic deposits brings the total number of such identified features from 40 to 51. Some 90% of pyroclastic deposits are found within impact craters. The locations of most pyroclastic deposits appear to be unrelated to regional smooth plains deposits, except some deposits cluster around the margins of smooth plains, similar to the relation between many lunar pyroclastic deposits and lunar maria. A survey of the degradation state of the impact craters that host pyroclastic deposits suggests that pyroclastic activity occurred on Mercury over a prolonged interval. Measurements of surface reflectance by MESSENGER indicate that the pyroclastic deposits are spectrally distinct from their surrounding terrain, with higher reflectance values, redder (i.e., steeper) spectral slopes, and a downturn at wavelengths shorter than ~400 nm (i.e., in the near‐ultraviolet region of the spectrum). Three possible causes for these distinctive characteristics include differences in transition metal content, physical properties (e.g., grain size), or degree of space weathering from average surface material on Mercury. The strength of the near‐ultraviolet downturn varies among spectra of pyroclastic deposits and is correlated with reflectance at visible wavelengths. We suggest that this interdeposit variability in reflectance spectra is the result of either variable amounts of mixing of the pyroclastic deposits with underlying material or inherent differences in chemical and physical properties among pyroclastic deposits.

Thermal-maturity limit for primary thermogenic-gas generation from humic coals as determined by hydrous pyrolysis

Hydrous-pyrolysis experiments at 360°C (680°F) for 72 h were conducted on 53 humic coals representing ranks from lignite through anthracite to determine the upper maturity limit for hydrocarbon-gas generation from their kerogen and associated bitumen (i.e., primary gas generation). These experimental conditions are below those needed for oil cracking to ensure that generated gas was not derived from the decomposition of expelled oil generated from some of the coals (i.e., secondary gas generation). Experimental results showed that generation of hydrocarbon gas ends before a vitrinite reflectance of 2.0%. This reflectance is equivalent to Rock-Eval maximum-yield temperature and hydrogen indices (HIs) of 555°C (1031°F) and 35 mg/g total organic carbon (TOC), respectively. At these maturity levels, essentially no soluble bitumen is present in the coals before or after hydrous pyrolysis. The equivalent kerogen atomic H/C ratio is 0.50 at the primary gas-generation limit and indicates that no alkyl moieties are remaining to source hydrocarbon gases. The convergence of atomic H/C ratios of type-II and -I kerogen to this same value at a reflectance of indicates that the primary gas-generation limits for humic coal and type-III kerogen also apply to oil-prone kerogen. Although gas generation from source rocks does not exceed vitrinite reflectance values greater than , trapped hydrocarbon gases can remain stable at higher reflectance values. Distinguishing trapped gas from generated gas in hydrous-pyrolysis experiments is readily determined by of the hydrocarbon gases when a -depleted water is used in the experiments. Water serves as a source of hydrogen in hydrous pyrolysis and, as a result, the use of -depleted water is reflected in the generated gases but not pre-existing trapped gases.

Application of remote sensing in exploration for uranium mineralization in Gabal El Sela area, South Eastern Desert, Egypt

This research aims at integrating remote sensing data and field studies to prospect for radioactive materials at Gabal El Sela area, South Eastern Desert of Egypt. This area is a part of the Arabo-Nubian shield, which is constituted by Late Precambrian basement rocks and developed during the Pan African tectono-thermal event. Geological interpretation of Landsat ETM+ image and field studies revealed that the study area is mainly covered by ophiolitic ultramafic rocks, intermediate metavolocanics, granodiorites, biotite granites and garnetiferous muscovite granites. These rocks are injected by pegmatitic and quartz veins and cut by acidic and basic dykes. The processed Landsat ETM+ data enable also to identify uraniferous alteration zones hosted in the granitic rocks (using band ratio 5/7, 4/5, 3/1 in RGB, density slicing and supervised classification techniques). The measured reflectance values (DNs) of six spectral bands of Landsat ETM+ for all exposed rock types in the study area show that the alteration zones have the highest reflectance values. The study recorded the presence of uranium mineralizations in alteration zones associating with the granitic rocks occurring along ENE–WSW trending shear zones. Three uranium-bearing alteration zones hosted in granitic rocks were detected. These zones are characterized by ferrugination, silicification, grizenization and kaolinitization. The most promising alteration zones (Site 1) occurs at the northeastern part of Gabal El Sela and is characterized by very high radioactive anomalies (up to 5000ppm eU). Microprobe analyses of samples collected from these alteration zones reveal the presence of uraninite crystals. It seems that the high fractures density of the granitic rocks acted as good channels for the ascending hydrothermal fluids and the percolating meteoric water, that leached the uranium minerals disseminated all over the rocks and redeposited them along the fractures of the shear zones. This study demonstrates the utility of orbital remote sensing data for finding unknown mineralized zones in the Eastern Desert of Egypt and similar arid regions.

Impacts of microphysical scheme on convective and stratiform characteristics in two high precipitation squall line events

AbstractThis study investigates the impact of snow, graupel, and hail processes on simulated squall lines over the Southern Great Plains in the United States. The Weather Research and Forecasting (WRF) model is used to simulate two squall line events in Oklahoma during May 2007, and the simulations are validated against radar and surface observations. Several microphysics schemes are tested in this study, including the WRF 5‐Class Microphysics (WSM5), WRF 6‐Class Microphysics (WSM6), Goddard Cumulus Ensemble (GCE) Three Ice (3‐ice) with graupel, Goddard Two Ice (2‐ice), and Goddard 3‐ice hail schemes. Simulated surface precipitation is sensitive to the microphysics scheme when the graupel or hail categories are included. All of the 3‐ice schemes overestimate the total precipitation with WSM6 having the largest bias. The 2‐ice schemes, without a graupel/hail category, produce less total precipitation than the 3‐ice schemes. By applying a radar‐based convective/stratiform partitioning algorithm, we find that including graupel/hail processes increases the convective areal coverage, precipitation intensity, updraft, and downdraft intensities, and reduces the stratiform areal coverage and precipitation intensity. For vertical structures, simulations have higher reflectivity values distributed aloft than the observed values in both the convective and stratiform regions. Three‐ice schemes produce more high reflectivity values in convective regions, while 2‐ice schemes produce more high reflectivity values in stratiform regions. In addition, this study has demonstrated that the radar‐based convective/stratiform partitioning algorithm can reasonably identify WRF‐simulated precipitation, wind, and microphysical fields in both convective and stratiform regions.

Design and fabrication of amorphous germanium thin film-based single-material distributed Bragg reflectors operating near 22 μm for long wavelength applications

We report the design and fabrication of single-material distributed Bragg reflectors (DBRs) composed of amorphous germanium (a-Ge) thin films by a glancing angle deposition and their optical reflectance characteristics in the long wavelength region of 1.7–3.1 μm, together with the aid of theoretical analysis using a rigorous coupled-wave analysis method. The refractive index of the a-Ge films is estimated from the measured transmittance spectra. The high and low refractive indices a-Ge films (i.e., Δn∼2.18), which compose the alternative layers of DBRs, were fabricated at two incident vapor flux angles (θα) of 0° and 80°, respectively, by determining the quarter wavelength thicknesses of 135 nm at θα=0° and 291 nm at θα=80° for a center wavelength (λc) of ∼2.2 μm. For the fabricated a-Ge/a-Ge DBR with only 5 pairs, the normalized stop bandwidth (Δλ/λc) of ∼22.3% was measured while maintaining high reflectance values of >99% over a wide wavelength range of 2.06–2.55 μm, which indicates a reasonable consistency with the calculated reflectance results.

Study the Spectral reflectance and factor affecting they for the dominate land cover by using remote sensing technique in Abu-Gharib projection.

Image of landsate-7 taken by thematic mapper was used and classified using supervised method. Results of supervised classification indicated presence of nine land cover classes. Salt-soils class shows the highest reflectance value while water bodies' class shows the lowest values. Also the results indicated that soil properties show different effects on reflectance. There was a high significant positive relation of carbonate, gypsum, electric conductivity and silt content, while there was a week positive relation with sand and negative relation with organic matter, water content, bulk density and cataion exchange capacity.

Comparing the Convective Structure and Microphysics in Two Sahelian Mesoscale Convective Systems: Radar Observations and CRM Simulations

Abstract Two mesoscale convective systems (MCSs) observed during the African Monsoon Multidisciplinary Analyses (AMMA) experiment are simulated using the three-dimensional (3D) Goddard Cumulus Ensemble model. This study was undertaken to determine the performance of the cloud-resolving model in representing distinct convective and microphysical differences between the two MCSs over a tropical continental location. Simulations are performed using 1-km horizontal grid spacing, a lower limit on current embedded cloud-resolving models within a global multiscale modeling framework. Simulated system convective structure and microphysics are compared to radar observations using contoured frequency-by-altitude diagrams (CFADs), calculated ice and water mass, and identified hydrometeor variables. Vertical distributions of ice hydrometeors indicate underestimation at the mid- and upper levels, partially due to the inability of the model to produce adequate system heights. The abundance of high-reflectivity values below and near the melting level in the simulation led to a broadening of the CFAD distributions. Observed vertical reflectivity profiles show that high reflectivity is present at greater heights than the simulations produced, thought to be a result of using a single-moment microphysics scheme. Relative trends in the population of simulated hydrometeors are in agreement with observations, though a secondary convective burst is not well represented. Despite these biases, the radar-observed differences between the two cases are noticeable in the simulations as well, suggesting that the model has some skill in capturing observed differences between the two MCSs.

Why does radar reflectivity tend to increase downward toward the ocean surface, but decrease downward toward the land surface?

Both ground and space borne radars have shown that radar reflectivity profiles below the freezing level have different slopes over land and ocean in general. This is critical in correctly estimating the surface precipitation rate in the usual situation in which the radar reflectivity cannot be measured as close to the surface as one would like. Using 14 years of Tropical Rainfall Measuring Mission precipitation radar observations, the variations of slopes of the radar reflectivity in the low troposphere are examined over the stratiform and convective precipitation regions. Radar reflectivity below the freezing level usually decreases toward the surface over land, but increases toward the surface over the ocean. Increasing reflectivity toward the surface is hypothesized to occur mainly when raindrops grow while falling through low clouds, which is favored by high humidity at low levels, and by updraft speeds lower than the fall speed of raindrops, both more likely over oceans. Other things being equal, proxy evidence is presented that the more intense the convection, the more likely reflectivity is to decrease toward the surface, and that this is at least as important as low‐level relative humidity. Over monsoon regions with more moderate convection but higher humidity, such as southeast China and the Amazon, there are more profiles with reflectivity increasing toward the surface than over other continental regions such as Africa. Radar reflectivity tends to increase toward the surface in shallow warm rain systems in trade cumulus regions, but tends to decrease toward the surface when high reflectivity values are present at or above the freezing level.

Comparative analysis of morphological, mineralogical and spectral properties of cryoconite in Jakobshavn Isbræ, Greenland, and Canada Glacier, Antarctica

AbstractWe report the results of a comparative analysis focusing on grain size, mineralogical composition and spectral reflectance values (400-2500 nm) of cryoconite samples collected from Jakobshavn Isbræ, West Greenland, and Canada Glacier, McMurdo Dry Valleys, Antarctica. The samples from the Greenland site were composed of small particles clumped into larger rounded agglomerates, while those from the site in Antarctica contained fragments of different sizes and shapes. Mineralogical analysis indicates that the samples from Jakobshavn Isbræ contained a higher percentage of quartz and albite, whereas those from Canada Glacier contained a higher percentage of amphibole, augite and biotite. Spectral measurements confirmed the primary role of organic material in reducing the reflectance over the measured spectrum. The reflectance of the samples from the Antarctic site remained low after the removal of organic matter because of the higher concentration of minerals with low reflectance. The reflectance of dried cryoconite samples in the visible region was relatively low (e.g. between ∼0.1 and ∼0.4) favouring increased absorbed solar radiation. Despite high reflectance values in the shortwave infrared region, the effect of the presence of cryoconite is negligible at infrared wavelengths where ice reflectance is low.

Doppler weather radar observations of the 2009 eruption of Redoubt Volcano, Alaska

The U.S. Geological Survey (USGS) deployed a transportable Doppler C-band radar during the precursory stage of the 2009 eruption of Redoubt Volcano, Alaska that provided valuable information during subsequent explosive events. We describe the capabilities of this new monitoring tool and present data captured during the Redoubt eruption. The MiniMax 250-C (MM-250C) radar detected seventeen of the nineteen largest explosive events between March 23 and April 4, 2009. Sixteen of these events reached the stratosphere (above 10km) within 2–5min of explosion onset. High column and proximal cloud reflectivity values (50 to 60dBZ) were observed from many of these events, and were likely due to the formation of mm-sized accretionary tephra-ice pellets. Reflectivity data suggest that these pellets formed within the first few minutes of explosion onset. Rapid sedimentation of the mm-sized pellets was observed as a decrease in maximum detection cloud height. The volcanic cloud from the April 4 explosive event showed lower reflectivity values, due to finer particle sizes (related to dome collapse and related pyroclastic flows) and lack of significant pellet formation. Eruption durations determined by the radar were within a factor of two compared to seismic and pressure-sensor derived estimates, and were not well correlated. Ash dispersion observed by the radar was primarily in the upper troposphere below 10km, but satellite observations indicate the presence of volcanogenic clouds in the stratosphere. This study suggests that radar is a valuable complement to traditional seismic and satellite monitoring of explosive eruptions.

Broadband and wide-angle distributed Bragg reflectors based on amorphous germanium films by glancing angle deposition

We fabricated the distributed Bragg reflectors (DBRs) with amorphous germanium (a-Ge) films consisted of the same materials at a center wavelength (λc) of 1.33 μm by the glancing angle deposition. Their optical reflectance properties were investigated in the infrared wavelength region of 1-1.9 μm at incident light angles (θ inc) of 8-70°, together with the theoretical analysis using a rigorous coupled-wave analysis simulation. The two alternating a-Ge films at the incident vapor flux angles of 0 and 75° were formed as the high and low refractive index materials, respectively. The a-Ge DBR with only 5 periods exhibited a normalized stop bandwidth (∆λ/λ c) of ~24.1%, maintaining high reflectance (R) values of > 99%. Even at a high θ inc of 70°, the ∆λ/λ c was ~21.9%, maintaining R values of > 85%. The a-Ge DBR with good uniformity was obtained over the area of a 2 inch Si wafer. The calculated reflectance results showed a similar tendency to the measured data.

Nanosized MEL zeolite and GeSe2 chalcogenide layers as functional building blocks of tunable Bragg stacks

The utilization of chalcogenide and zeolite layers resulted in omni-directional tunable Bragg stacks with high optical contrast and high reflectance value making them usable as selective chemical sensors with optical read-out.

Spectroscopy of the mineralized tonalite–diorite intrusions, Bulghah gold mine area, Saudi Arabia: Effects of opaques and alteration products on Fieldspec data

This paper aims to reveal the spectral characteristics of the mineralized tonalite–diorite intrusions exposed at Bulghah gold mine area, Saudi Arabia, using FieldSpec spectroradiometer and Landsat ETM + data. Gold mineralization at Bulghah gold mine is hosted mainly by Syn- to Late-orogenic tonalite–diorite intrusions aligned in N–S direction and is associated mainly with cataclastic zones and quartz veins. Based on field, petrography and FieldSpec data two main tonalite–diorite groups namely A and B are recognized. Group “A”, recorded at the mine area, is characterized by low flat spectral profiles with overall low reflectance values (~ 10%). These low values are attributed to the presence of high content of trans-opaque phases (hematite and goethite) as indicated by petrographic study. Spectral profiles of group “B”, recorded at Bulghah North area, show high reflectance values (~ 40%) with three main absorption features around the 1.45 μm, 2.20 μm and 2.35 μm wavelength regions. These absorption features are attributed mainly to the presence of clay minerals, sericite, chlorite and carbonate alteration products. To discriminate the above mentioned tonalite–diorite groups, band ratios and Minimum Noise Fraction (MNF) techniques are conducted. Landsat false color composite band ratio image (7/4:R, 4/1:G and 4/5:B) discriminates easily the bluish brick red tonalite–diorite intrusions from the surrounding rock units but failed to distinguish the above mentioned two tonalite–diorite groups. On MNF3 image, the two tonalite–diorite groups can be distinguished easily in which group “A” has white color whereas group “B” has gray color. The present study proved the usefulness of FieldSpec spectral profiles and the processed Landsat ETM + data for discriminating and delineating the mineralized tonalite–diorite intrusions exposed at the study area.

Micro-Raman spectroscopy of carbonized semifusinite and fusinite

Abstract The purpose of the study was to present application of micro-Raman spectroscopy for examination of coal macerals and to characterize the internal structure of semifusinite and fusinite heated at 400–1200 °C, in an argon atmosphere. Examination was performed on inertinite concentrates prepared from three samples of steam and coking bituminous coals ( R r = 0.98–1.42%) from the Upper Silesian Coal Basin of Poland. Fusinite and semifusinite, as well as reactive and non-reactive forms of the latter maceral differ in terms of structural properties, as inferred from the Raman-derived parameters. Behavior of both macerals under heat-treatment is determined by their structural and chemical properties. Carbonization causes rebuilding of macromolecular network of semifusinite and fusinite resulting in the growth of polyaromatic units and, in case of the former maceral, also increases in structural organization. This is followed by significant reflectance increase. Semifusinite carbonized at 1200 °C has larger coherent domains and they are more ordered than in fusinite, which results in higher reflectance value. The A D3 + D4 /A ALL ratio may be used as a measure of inertinite reactivity. Significant relationships between random reflectance ( R r ) of semifusinite and fusinite and the I D1 /I G ratio and position of most Raman bands (G, D1, D2 and D3) for the studied temperature range were found.