Application of Spectral Angle Mapper Classification to Discriminate Hydrothermal Alteration in Southwest Birjand, Iran, Using Advanced Spaceborne Thermal Emission and Reflection Radiometer Image Processing

The purpose of this study is to evaluate the Spectral Angle Mapper （SAM） classification method for determining the optimum threshold （maximum spectral angle） to unveil the hydrothermal mineral assemblages related to mineral deposits. The study area indicates good potential for Cu-Au porphyry, epithermal gold deposits and hydrothermal alteration well developed in arid and semiarid climates, which makes this region significant for Advanced Spaceborne Thermal Emission and Reflection Radiometer （ASTER） image processing analysis. Given that achieving an acceptable mineral mapping requires knowing the alteration patterns, petrochemistry and petrogenesis of the igneous rocks while considering the effect of weathering, overprinting of supergene alteration, overprinting of hypogene alteration and host rock spectral mixing, SAM classification was implemented for argillic, sericitic, propylitic, alunitization, silicification and iron oxide zones of six previously known mineral deposits： Maherabad, a Cu-Au porphyry system; Sheikhabad, an upper part of Cu-Au porphyry system; Khoonik, an Intrusion related Au system; Barmazid, a low sulfidation epithermal system; Khopik, a Cu-Au porphyry system; and Hanish, an epithermal Au system. Thus, the investigation showed that although the whole alteration zones are affected by mixing, it is also possible to produce a favorable hydrothermal mineral map by such complementary data as petrology, petrochemistry and alteration patterns.

Three-Component Model for Bidirectional Reflection Distribution Function of Thermal Coating Surfaces

We present a bidirectional reflection distribution function （BRDF） model for thermal coating surfaces based on a three-component reflection assumption, in which the specular reflection is given according to the microfacet theory and Snell＇s law, the multiple reflection is considered Nth cosine distributed, and the volume scattering is uniformly distributed in reflection angles according to the experimental results. This model describes the reflection characteristics of thermal coating surfaces more completely and reasonably. Simulation and measurement results of two thermal coating samples SR107 and S781 are given to validate that this three-component model significantly improves the modeling accuracy for thermal coating surfaces compared with the existing BRDF models.

Quantitative Assessment of Remotely Sensed Global Surface Models Using Various Land Classes Produced from Landsat Data in Istanbul

Digital elevation model （DEM） is the most popular product for three-dimensional （3D） digital representation of bare Earth surface and can be produced by many techniques with different characteristics and ground sampling distances （GSD）. Space-borne opti- cal and synthetic aperture radar （SAR） imaging are two of the most preferred and modern techniques for DEM generation. Using them, global DEMs that cover almost entire Earth are produced with low cost and time saving processing. In this study, we aimed to assess the Satellite pour robservation de la Terre-5 （SPOT-5）, High Resolution Stereoscopic （HRS）, the Advanced Space-borne Thermal Emission and Reflection Radiometer （ASTER）, and the Shuttle Radar Topography Mission （SRTM） C-band global DEMs, produced with space-borne optical and SAR imaging. For the assessment, a reference DEM derived from 1 ： 1000 scaled digital photogrammetric maps was used. The study is performed in 100 km2 study area in Istanbul including various land classes such as open land, forest, built-up land, scrub and rough terrain obtained from Landsat data. The analyses were realized considering three vertical accuracy types as fundamental, supplemental, and consolidated, defined by national digital elevation program （NDEP） of USA. The results showed that, vertical accuracy of SRTM C-band DEM is better than optical models in all three accuracy types despite having the largest grid spacing. The result of SPOT-5 HRS DEM is very close by SRTM and superior in comparison with ASTER models.

Enhanced Destriping of Satellite Data of Ice Surface in Antarctica

This paper briefly reviews the cause of the striping and then develops a tapered (Chebwin & Kaiser) window finite impulse response (FIR) filter and a constrained least squares FIR filter by reason of the striping of ASTER satellite data . Both filters minimize the stripes in the visible data and simultaneously minimize any distortion in the filtered data. Finally, the results obtained by using these new filtering methods are quantitatively compared with those produced by other destriping methods.

Mo/Si multilayers used for the EUV normal incidence solar telescope

This paper first reviews an EUV normal incidence solar telescope that we have developed in our lab. The telescope is composed of four EUV telescopes and the operation wavelengths are 13.0 nm, 17.1 nm, 19.5 nm, and 30.4 nm. These four wavelengths, fundamental to the research of the solar activity and the atmosphere dynamics, are always chosen by the EUV normal incidence solar telescope. In the EUV region, almost all materials have strong absorption, so optics used in this region must be coated by the multilayer. The Mo/Si multilayers used for the EUV normal incidence solar telescope are designed and fabricated by the magnetron sputtering coating machine. The characteristics of these multilayers, such as reflectivity and thermal stability at wavelengths of 13.0 nm, 17.1 nm, 19.5 nm and 30.4 nm, are also described. All the multilayers were measured by a hard X-ray diffractometer (XRD) and an EUV/soft X-ray reflectometer (EXRR) before and after heating (in a vacuum chamber) at 100℃ for 24 hours and at 200℃ for 1 hour and 4 hours. The results show that Mo/Si multilayers have high reflectivity at 13.0 nm, 17.1 nm, and 19.5 nm but low at 30.4 nm. We found no change in the reflectivity and center wavelength of these multilayers by comparing the reflectivity curves before and after heating. This suggests the thermal stability of Mo/Si multilayers may meet our requirement in future solar observation missions.