Статті в журналах: "Satellite spots"

1

Hanley, Kipp. "Satellite Technology Spots Distribution System Leaks." Opflow 46, no. 4 (April 2020): 24–25. http://dx.doi.org/10.1002/opfl.1353.

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2

Pilyugin, L. S., B. Cedrés, I. A. Zinchenko, A. M. Pérez Garcia, M. A. Lara-López, J. Nadolny, Y. A. Nefedyev, et al. "MaNGA galaxies with off-centered spots of enhanced gas velocity dispersion." Astronomy & Astrophysics 653 (September 2021): A11. http://dx.doi.org/10.1051/0004-6361/202141012.

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Off-centered spots of the enhanced gas velocity dispersion, σ, are revealed in some galaxies from the Mapping Nearby Galaxies at Apache Point Observatory survey (MaNGA). Aiming to clarify the origin of the spots of enhanced σ, we examine the distributions of the surface brightness, the line-of-sight velocity, the oxygen abundance, the gas velocity dispersion, and the Baldwin-Phillips-Terlevich spaxel classification in seven galaxies. We find that the enhanced σ spots in six galaxies can be attributed to a (minor) interaction with a satellite. Three galaxies in our sample have a very close satellite (the separation in the sky plane is comparable to the optical radius of the galaxy). The spots of enhanced σ in those galaxies are located at the edge of the galaxy close to the satellite. The spots of enhanced σ in three other galaxies are related to bright spots in the photometric B band within the galaxy, which can be due to the projection of a satellite in the line of sight of the galaxy. The oxygen abundances in the spots in these three galaxies are reduced. This suggests that the low-metallicity gas from the satellite is mixed with the interstellar medium of the disk, that is, the gas exchange between the galaxy and its satellite takes place. The spectra of the spaxels within a spot are usually H II-region-like, suggesting that the interaction (gas infall) in those galaxies does not result in appreciable shocks. In contrast, the spot of the enhanced σ in the galaxy M-8716-12703 is associated with an off-centered active galactic nucleus-like radiation distribution. One can suggest that the spot of the enhanced σ in the M-8716-12703 galaxy is different in origin, or that the characteristics of gas infall in this case differs from that in other galaxies.

3

Zhang, Jia Hua, and Feng Mei Yao. "Advance in Monitoring Forest Fire in China Based on Multi-Satellite Data." Advanced Materials Research 518-523 (May 2012): 5668–72. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.5668.

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The advance in monitoring forest fire in China based on multi-Satellite data were discussed in the paper. Since the 1980s in China, the satellite remotely-sensed data have been acquired, such as NOAA/AVHRR, FY-series, MODIS, CBERS, and ENVISAT, have been widely utilized for monitoring forest fire hot spots and burned areas in China. Some developed algorithms have been utilized for detecting the forest fire hot spots.

4

Goguen, J. D., W. M. Sinton, D. L. Matson, R. R. Howell, H. M. Dyck, T. V. Johnson, R. H. Brown, et al. "Io hot spots: Infrared photometry of satellite occultations." Icarus 76, no. 3 (December 1988): 465–84. http://dx.doi.org/10.1016/0019-1035(88)90015-2.

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5

Stokel-Walker, Chris. "AI spots possible archaeological sites in satellite images." New Scientist 257, no. 3427 (February 2023): 9. http://dx.doi.org/10.1016/s0262-4079(23)00323-8.

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6

Zhang, Hongbo, Ke Wang, and Xiaoyu Shang. "High time effective detection strategy for geosynchronous orbital space debris." Journal of Physics: Conference Series 2764, no. 1 (May 1, 2024): 012087. http://dx.doi.org/10.1088/1742-6596/2764/1/012087.

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Abstract After the formation of a multi-satellite network in a hypersynchronous orbit, it has the ability to continuously and in real-time observe the GEO band, which is an ideal way to solve blind spots and semi-backlight observations and improve the system’s high time-effective coverage ability. In response to the application limitations of high-orbit real-time monitoring constellations in hypersynchronous orbits, such as the large number of satellites in the network, high requirements for satellite detection capability, large field of view, and high launch and orbit cost, this paper proposes a constellation system efficiency analysis method that comprehensively covers both time and space dimensions. Based on this, optimization analysis of satellite detection capability, detection field of view, number of satellites, and orbit height is carried out. Finally, three constellation optimization schemes are provided, which are a semi-major axis of 60000 km with seven satellites, a semi-major axis of 55000 km with eight satellites, and a semi-major axis of 50000 km with ten satellites. The three constellation optimization schemes can provide a reference for the development of space-based high-orbit situational awareness in the future.

7

Mupfiga, Upenyu Naume, Onisimo Mutanga, Timothy Dube, and Pedzisai Kowe. "Spatial Clustering of Vegetation Fire Intensity Using MODIS Satellite Data." Atmosphere 13, no. 12 (November 25, 2022): 1972. http://dx.doi.org/10.3390/atmos13121972.

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This work analyses the spatial clustering of fire intensity in Zimbabwe, using remotely sensed Moderate Resolution Imaging Spectroradiometer (MODIS) active fire occurrence data. In order to investigate the spatial pattern of fire intensity, MODIS-derived fire radiative power (FRP) was utilized. A local indicator of spatial autocorrelation method, the Getis-Ord (Gi*) spatial statistic, was applied to show the spatial distribution of high and low fire intensity clusters. Analysis of the relationship between topographic variables, vegetation type, agroecological zones and fire intensity was done. According to the study’s findings, the majority (44%) of active fires detected in the study area in 2019 were of low-intensity (cold spots), and the majority (49.3%) of them occurred in shrubland. High-intensity fires (22%) primarily occurred in the study area’s eastern and western regions. The study findings demonstrate the utility of spatial statistics methods in conjunction with satellite fire data in detecting clusters of high and low-intensity fires (hot spots and cold spots).

8

Wang, N., and R. Yang. "THE APPLICATION OF CHINESE HIGH-SPATIAL-RESOLUTION REMOTE SENSING SATELLITE IMAGE IN LAND LAW ENFORCEMENT INFORMATION EXTRACTION." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3 (April 30, 2018): 1751–55. http://dx.doi.org/10.5194/isprs-archives-xlii-3-1751-2018.

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Chinese high -resolution (HR) remote sensing satellites have made huge leap in the past decade. Commercial satellite datasets, such as GF-1, GF-2 and ZY-3 images, the panchromatic images (PAN) resolution of them are 2&thinsp;m, 1&thinsp;m and 2.1&thinsp;m and the multispectral images (MS) resolution are 8&thinsp;m, 4&thinsp;m, 5.8&thinsp;m respectively have been emerged in recent years. Chinese HR satellite imagery has been free downloaded for public welfare purposes using. Local government began to employ more professional technician to improve traditional land management technology. This paper focused on analysing the actual requirements of the applications in government land law enforcement in Guangxi Autonomous Region. 66 counties in Guangxi Autonomous Region were selected for illegal land utilization spot extraction with fusion Chinese HR images. The procedure contains: A. Defines illegal land utilization spot type. B. Data collection, GF-1, GF-2, and ZY-3 datasets were acquired in the first half year of 2016 and other auxiliary data were collected in 2015. C. Batch process, HR images were collected for batch preprocessing through ENVI/IDL tool. D. Illegal land utilization spot extraction by visual interpretation. E. Obtaining attribute data with ArcGIS Geoprocessor (GP) model. F. Thematic mapping and surveying. Through analysing 42 counties results, law enforcement officials found 1092 illegal land using spots and 16 suspicious illegal mining spots. The results show that Chinese HR satellite images have great potential for feature information extraction and the processing procedure appears robust.

9

Shiohara, Amane, Sergey M. Novikov, Diego M. Solís, José M. Taboada, Fernando Obelleiro, and Luis M. Liz-Marzán. "Plasmon Modes and Hot Spots in Gold Nanostar–Satellite Clusters." Journal of Physical Chemistry C 119, no. 20 (December 10, 2014): 10836–43. http://dx.doi.org/10.1021/jp509953f.

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10

Bonfond, B., D. Grodent, S. V. Badman, J. Saur, J. C. Gérard, and A. Radioti. "Similarity of the Jovian satellite footprints: Spots multiplicity and dynamics." Icarus 292 (August 2017): 208–17. http://dx.doi.org/10.1016/j.icarus.2017.01.009.

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11

Stopic, Renato, Eduardo Dias, Maurice de Kleijn, and Eric Koomen. "Satellite parking: a new method for measuring parking occupancy." AGILE: GIScience Series 4 (June 6, 2023): 1–5. http://dx.doi.org/10.5194/agile-giss-4-44-2023.

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Abstract. Parking management plays a critical role in keeping urban spaces accessible and urban managers strive for an optimal balance between not enough and too much parking. Deciding which parking space can be liberated or needs to be extended requires detailed data on parking occupancy trends. In person inspection and in-situ sensors can provide such data but are too costly for city wide deployment. High-resolution satellite imagery is becoming more affordable, has the advantage of instantaneously collecting information from the whole city, is continuously being updated, and available for several years now to allow building a time series. Yet, identifying cars in satellite imagery is not a trivial task. We propose a method for classifying parking spot occupancy based on thresholding the reflectance range. The method requires individual parking spot data to be available and analyses each parking zone individually. We tested the method on a 0.5 metre resolution image (Pleiades satellite) that was specifically ordered for this purpose during a clear spring day in a medium-size city. The method has the advantage of not requiring extensive training data and is non-parametric. To assess accuracy, we collected ground truth data for the exact same moment as the image was ordered. The colour bands (blue, green, and red) performed equally well, while NIR seriously underperformed. We achieved a F1 score of 0.82 for all parking spots in the ground truth. The method is sensitive to tree canopy. When removing the tree obscured spots, the F1 score increased to 0.85. Tree canopy spots were automatically determined and filtered using NDVI.

12

Grankov, A. G., E. P. Novichikhin, and N. K. Shelobanova. "On the Problems of Monitoring Atmospheric Humidity Fields Using Satellite Microwave Radiometry Methods When Studying Cyclogenesis in the Tropical Atlantic." Радиотехника и электроника 68, no. 11 (November 1, 2023): 1072–78. http://dx.doi.org/10.31857/s0033849423110049.

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Some problems of microwave radiometric methods for monitoring fields of total atmospheric moisture content from satellites in areas of hurricane formation in the tropical regions of the Atlantic are considered. The possibilities of using polar-orbiting satellites (DMSP, EOS Aqua, GCOM-W1) for these tasks are analyzed a feature of which is the presence of gaps in satellite data (blind spots) resulting from divergence of scanning bands at lower latitudes. It is shown through a number of examples that the joint use of various satellites makes it possible to reduce the influence of this effect and obtain a clear picture of the evolution of atmospheric humidity fields in the tropical Atlantic and their connection with the evolution of tropical waves that initiate the formation of hurricanes.

13

Palkin, M. V. "Satellite Formation Flying Control Using Image Processing." Mekhatronika, Avtomatizatsiya, Upravlenie 20, no. 1 (January 15, 2019): 52–58. http://dx.doi.org/10.17587/mau.20.52-58.

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A problem of a formation flying control is observed. As an example a concept of a multysatellite configuration ("space commercial") is described. Space advertisement is realized by groups of specialized free flying and cable-connected satellites, and their combinations. Construction of a space commercial satellite and a set of a control system equipment is presented. Several methods for group configuration are presented: periodic impulse correction of each flying satellite position formation; method of a satellite positioning on nocoplanar orbits. Other methods include combinations of methods mentioned above. Configuration control using onboard video camera with a wide-angle image detector is presented. Characteristics of an optical system are shown. Navigation parameters of a using a received observed videoimage are estimated. A method of a relative position measurement is described. The method detects a video track of a moving ahead satellite on the matrix detector. According to the method lines of the matrix detector are positioned transversely and columns are positioned in parallel with vertical axis of the orbital coordinate system. Course of the slave satellite is proportional to the travel of the centre of the lider satellite mark on the matrix detector columns. Pitch of the slave satellite is proportional to the travel of the centre of the leader satellite mark on the matrix detector lines. A video-display processing algorithm is developed and researched. The algorithm contains procedures of a forming, localization of the leader satellite mark, deviation angle calculation. The algorithm uses structural method, detecting bright spots (image syntactic characteristics). Efficiency of the algorithm depends on the leader satellite mark brightness, size, light-striking, distance.

14

Nazari, Rouzbeh, Husam Alfergani, Francis Haas, Maryam E. Karimi, Md Golam Rabbani Fahad, Samain Sabrin, Jess Everett, Nidhal Bouaynaya, and Robert W. Peters. "Application of Satellite Remote Sensing in Monitoring Elevated Internal Temperatures of Landfills." Applied Sciences 10, no. 19 (September 28, 2020): 6801. http://dx.doi.org/10.3390/app10196801.

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Subsurface fires and smoldering events at landfills can present serious health hazards and threats to the environment. These fires are much more costly and difficult to extinguish than open fires at the landfill surface. The initiation of a subsurface fire may go unnoticed for a long period of time and undetected fires may spread over a large area. Unfortunately, not all landfill operators keep or publish heat elevation data and many landfills are not equipped with a landfill gas extraction system to control subsurface temperatures generated from the chemical reactions within. The timely and cost-effective identification of subsurface fires is an important and pressing issue. In this work, we describe a method for using satellite thermal infrared imagery at a moderate spatial resolution to identify the locations of subsurface fires and monitor their migration within landfills. The focus of this study was the Bridgeton Sanitary Landfill in Bridgeton, MO, USA where a subsurface fire was first identified in 2010 and continues to burn today. Observations from Landsat satellites over the last seventeen years were examined for surface temperature anomalies (or hot spots) that may be associated with subsurface fires. The results showed that the locations of hot spots identified in satellite imagery match the known locations of the subsurface fires. Changes in the hot-spot locations with time, as determined by in situ measurements, correspond to the spreading routes of the subsurface fires. These results indicate that the proposed approach based on satellite observations can be used as a tool for the identification of landfill subsurface fires by landfill owners/operators to monitor landfills and minimize the expenses associated with extinguishing landfill fires.

15

Zhao, Chun Lei, and Xia Hou. "Design & Application of Forest Fire Monitoring System by Remote Sensing for Beijing, Tianjin & Hebei." Advanced Materials Research 760-762 (September 2013): 1043–47. http://dx.doi.org/10.4028/www.scientific.net/amr.760-762.1043.

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In order to monitor the forest fire effectively and to reduce the loss caused by forest fire in North China areas, a forest fire monitoring system was designed. Based on satellite remote sensing data, GIS data and meteorological information, the system has functions such as processing of data, adjusting of forest fire index for judging hot spots, intelligent judging of hot spots, and analyzing of geographical information and weather condition of hot spots. Also fire information is issued on web and by short message service. The system makes the remote sensing monitoring of forest fire automatically.

16

Li, Qi, Wei Xu, Zhi Hai Xu, and Hua Jun Feng. "Accuracy Analysis of Centroid Detection Method Used to Star Sensor." Advanced Materials Research 468-471 (February 2012): 401–4. http://dx.doi.org/10.4028/www.scientific.net/amr.468-471.401.

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Star sensor is important equipment for measuring satellite attitude and motion, and star centroid detection accuracy is the basis of the overall accuracy of star sensor. In star sensors, slightly- defocus method is often adopted to acquire dispersive light spots so as to facilitate centroid detection, and certain motion blur can also be introduced because of the motion of satellites. In this paper, we analyzed several commonly-used centroid detection algorithms by using simulation experiment to study the influence of defocus and motion parameters on the accuracy of centroid detection algorithm and provided acceptable parameter value ranges.

17

Wu, Lianghai, Zhanchuan Cai, Xiu He, Yuyun Chen, and Zhiguo Meng. "Comparative Analysis of Diurnal Thermal Radiation Variation among Lunar Craters of Different Ages Using CE-2 MRM Data." Remote Sensing 15, no. 15 (August 3, 2023): 3857. http://dx.doi.org/10.3390/rs15153857.

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Microwave radiometer (MRM) is one of the important payloads on the Chang’e-2 (CE-2) Lunar satellite. In the Chang’e satellite’s observation of the microwave radiation brightness temperature (TB) on the lunar surface, there are some “cold spots” of microwave thermal radiation at night containing the Jackson crater. In order to compare the diurnal radiation TB differences of “cold spots” on the lunar surface, two typical craters at similar latitudes on the northern hemisphere on the lunar farside were selected: Jackson, which represents the new craters with a large number of discrete rocks on their surfaces; and Morse, which no longer has a large number of rocks after long-term meteorite impact and lunar evolution. In this paper, the diurnal variation of CE-2 MRM data in the two craters is presented, and a comparative analysis is made with the (FeO + TiO2) abundance (FTA) obtained by Clementine UV-VIS data and the rock abundance (RA) data of LRO Diviner. We find that the variation of the "cold spots" of lunar surface thermal radiation is closely related to the RA distribution in the newly formed craters on the lunar surface, and also has a certain correlation with the FTA.

18

Sultana, Urmi, Mashrun Hoque, Popy Akter, Maruful Islam, Md Abdullah Al Mahmud, Muhammad Towhidur Rahman, and A. H. M. Zadidul Karim. "Determination of Green Spots (Trees) For Google Satellite Images Using MATLAB." Procedia Computer Science 171 (2020): 1634–41. http://dx.doi.org/10.1016/j.procs.2020.04.175.

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19

Sukirman, Sukirman, Muhammad Ridwan, Muhammad Zainal, Rika Afriani, and Sri Hartati. "EFEKTIVITAS PEMANFAATAN SATELITE ASIASAT-9 UNTUK MENGATASI BLANK-SPOT (Studi Kasus pada TVRI Stasiun Sumatera Selatan)." Jurnal Ilmu Administrasi dan Studi Kebijakan (JIASK) 4, no. 2 (March 29, 2022): 143–58. http://dx.doi.org/10.48093/jiask.v4i2.86.

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This study carefully examines the effectiveness of using the Asiasat-9 Satellite to overcome the Blank Spot in the South Sumatra Province. This study is intended to analyze and formulate how the effectiveness of the use of the Asiasat-9 Satellite to overcome the Blank Spot in the Province of South Sumatra. Research through a qualitative approach is carried out based on the problem to be studied with an explanation with the aim of exploring or building a proposition or explaining the meaning behind reality. Careful measurement of certain social phenomena is a characteristic of the descriptive level of explanation, therefore this accuracy is the basis why this study uses the descriptive level. The results of the study explained that the organization of TVRI South Sumatra has tried to be a regulator in the region in carrying out and implementing the use of the Asiasat-9 Satellite to overcome the Blank Spot in the province of South Sumatra. In an effort to support the implementation of its duties, it is necessary to support the effectiveness of the organization. Therefore, the South Sumatra Station TVRI has made efforts to increase the effectiveness of the use of the Asiasat-9 Satellite to overcome Blank Spots in the South Sumatra Province. The effectiveness level of using the Asiasat-9 Satellite to overcome Blank Spots in the South Sumatra Province for the city of Palembang is quite good, but for the Muaraenim, Lahat, Pagaralam, Ranau areas sometimes the audio and video are lost, for the TVRI program it is good, but in receiving broadcasts via Satellite Asiasat-9 if it rains Blank broadcast

20

Wu, X. J., and S. Horiuchi. "TEM study on the diffraction streaks caused by initial phase disorder in a displacive modulation structure." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 4 (August 1990): 158–59. http://dx.doi.org/10.1017/s0424820100173923.

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Recently it was found in some electron diffraction patterns from one-dimensional displacive modulation structure that some streaks pass through the satellite spots. Fig.1 taken from a mineral Ankangite shows that the streaks always appear when the crystal was tilted along b*. This means than in this crystal there must be some reflection planes parallel to (a*, b*) plane in the reciprocal space. The similar EDPs are also observed in a crystal (Sr, Ca)3Cu5Ox. The streaks always pass through the satellite spots, which is quite different from the case where streaks are caused by conventional lattice defects like a stacking fault. It implies that in this kind of crystal the streaks must be produced by a new diffraction mechanism.An initial phase disorder model has been proposed to explain this diffraction phenomenon. So-called initial phase disorder means that the modulation wave is not a plane wave.

21

Kumalawati, R., A. Yuliarti, J. T. Raharjo, Rijanta, A. Susanti, E. Saputra, P. W. Budiman, et al. "Early Detection of Forest and Land Fires Using Hotspots Data from S-NPP VIIRS Satellite Imagery Recording in the New Capital City Location." IOP Conference Series: Earth and Environmental Science 1276, no. 1 (December 1, 2023): 012031. http://dx.doi.org/10.1088/1755-1315/1276/1/012031.

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Abstract Forest and land fires are a natural disaster whose frequency is increasing annually, especially during dry season, forest and land fires also impact the new capital city in East Kalimantan as well. Early detection is very critical to prevent increasing impact of forest and land fires. Early detection can be done using hotspot data from satellite image recording. Based on this, it is very necessary to conduct research entitled Early Detection of Forest and Land Fires Using Hot Spots from “S-NPP VIIRS Image Records in the New Capital City Location”. The research was conducted in the new capital city location in East Kalimantan Province which consists of several sub-districts and 10 districts / cities. Descriptive quantitative method is used to analysed secondary data consist of hotspot data in each sub-district from satellite imagery data record namely S-NPP VIIRS from 2012-2022. Population number is same as the number of samples, namely hotspots number in each sub-district. Descriptive geostatistical analysis technique in ArcGIS software is used to process hotspot data. It is known that from 2012-2022, Kutai Kartanegara has the highest hotspots number with 38,694 spots, it followed by East Kutai with 36,915 spots, both are viewed from district/city scope. When viewed on the district scope, the highest was in Bengalon district from East Kutai District with 9,027 spots, it followed by Muarakaman District from Kutai Kartanagara District with 7,713 spots. The number of hotspots varies quite a lot amongst sub-district in the new capital city location, whose each have a numerous number that needs serious attention in order to minimize the loss of life and property. From analysis above, early detection is very important as a form of early warning system.

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Moquin, Julie, Jordan Ealy, Joshua E. Schlieder, and Christopher Johns-Krull. "Localizing Stellar Activity on Low-mass Stars with the Transiting Exoplanet Survey Satellite." Research Notes of the AAS 8, no. 5 (May 22, 2024): 138. http://dx.doi.org/10.3847/2515-5172/ad4da0.

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Abstract Magnetic reconnection is the underlying cause of stellar flares which are linked to regions of high magnetic activity, like star spots. To understand trends in stellar activity, we need to study how it is heightened by rapid rotation and deep convection in young low-mass stars. We analyze light curves of such stars observed by the Transiting Exoplanet Survey Satellite to investigate trends in flare timing with starspot modulation signals. Trends in flare properties and spot modulation can provide a means to “localize” which face of a star flares more frequently and better understand their association with active regions. We present an analysis of light curves from M and K dwarfs with no companions from five nearby and young moving groups spanning ages ∼20–150 Myr. We discuss a technique to analyze the distribution of flares and star spots and describe our results, which reveal a tentative correlation.

23

Yang, Xiaomeng, Junfeng Xie, Ren Liu, Fan Mo, and Junze Zeng. "Centroid Extraction of Laser Spots Captured by Infrared Detectors Combining Laser Footprint Images and Detector Observation Data." Remote Sensing 15, no. 8 (April 18, 2023): 2129. http://dx.doi.org/10.3390/rs15082129.

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On-orbit geometric calibration of satellite-borne laser based on infrared detectors is the key tool to ensure the elevation measurement accuracy, and the accuracy of on-orbit geometric calibration is directly determined by laser spots captured by detectors. Mathematical methods, such as gray-scale barycenter, are widely applied for centroid extraction of spots captured by infrared detectors and completely depend on the energy values at points measured by detectors, which have low precision and are greatly affected by the consistency of the detectors and other factors at present. Based on the above question, considering the consistency between the real laser footprint shape and spot captured by detectors, a centroid extraction method of laser spots captured by infrared detectors combining laser footprint images and detector observation data is proposed for making up this defect to some extent. First, the self-adaptive “two-step method” is used to denoise footprint images hierarchically to obtain the real shape of footprints for constraining the spots captured by detectors, and then the centroids of spots are extracted by using the energy-weighted barycenter method based on regional blocks. In the experiment, Gaofen-7 (GF-7) satellite is taken as the research object, and the proposed method, as well as the other six methods, are used for the centroid extraction of laser spots captured by detectors, the calculation of calibration parameters based on the single-beam and dual-beam laser calibration models, the positioning of laser footprints, and cross verification. According to the results, the plane accuracy of centroid extraction using the proposed method is as follows: 0.34 grids for Beam 1 and 0.33 grids for Beam 2. In addition, on flat terrain, the elevation accuracy of Beam 1 and Beam 2 in 2021 is 5.2 cm and 5.0 cm, respectively, 0.6 cm and 4.2 cm higher than those in the most accurate one among other methods; the elevation accuracy in 2020 is 23.3 cm and 7.1 cm, respectively, 7.7 cm and 2.7 cm higher than those in the most accurate one among other methods. On slopes and gentle slopes, the method proposed is also superior to other methods. Since the change of pointing angle caused by satellite jitter, atmosphere, etc., between different years, the accuracy drops when laser footprints of 2020 are located using the parameters of 2021. In summary, under different terrains and years, the results fully demonstrate the effectiveness and accuracy of the proposed method, which has more significant advantages than other traditional methods.

24

Válio, Adriana, and Eduardo Spagiari. "Starspots Magnetic field by transit mapping." Proceedings of the International Astronomical Union 9, S302 (August 2013): 220–21. http://dx.doi.org/10.1017/s1743921314002129.

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AbstractSunspots are important signatures of the global solar magnetic field cycle. It is believed that other stars also present these same phenomena. However, today it is not possible to observe directly star spots due to their very small sizes. The method applied here studies star spots by detecting small variations in the stellar light curve during a planetary transit. When the planet passes in front of its host star, there is a chance of it occulting, at least partially, a spot. This allows the determination of the spots physical characteristics, such as size, temperature, and location on the stellar surface. In the case of the Sun, there exists a relation between the magnetic field and the spot temperature. We estimate the magnetic field component along the line-of-sight and the intensity of sunspots using data from the MDI instrument on board of the SOHO satellite. Assuming that the same relation applies to other stars, we estimate spots magnetic fields of CoRoT-2 and Kepler-17 stars.

25

Abraham, L., and M. Sasikumar. "Vehicle Detection and Classification from High Resolution Satellite Images." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences II-1 (November 7, 2014): 1–8. http://dx.doi.org/10.5194/isprsannals-ii-1-1-2014.

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In the past decades satellite imagery has been used successfully for weather forecasting, geographical and geological applications. Low resolution satellite images are sufficient for these sorts of applications. But the technological developments in the field of satellite imaging provide high resolution sensors which expands its field of application. Thus the High Resolution Satellite Imagery (HRSI) proved to be a suitable alternative to aerial photogrammetric data to provide a new data source for object detection. Since the traffic rates in developing countries are enormously increasing, vehicle detection from satellite data will be a better choice for automating such systems. In this work, a novel technique for vehicle detection from the images obtained from high resolution sensors is proposed. Though we are using high resolution images, vehicles are seen only as tiny spots, difficult to distinguish from the background. But we are able to obtain a detection rate not less than 0.9. Thereafter we classify the detected vehicles into cars and trucks and find the count of them.

26

Ginzburg, A. I., E. V. Krek, A. G. Kostianoy, and D. M. Soloviev. "ON THE ROLE OF MESOSCALE VORTICES IN THE OIL SPILL TRANSPORT IN THE SOUTH-EASTERN BALTIC SEA (SATELLITE INFORMATION)." DEDICATED TO THE 90TH ANNIVERSARY OF PROF. K.N. FEDOROV OCEAN PHYSICS 47, no. 3 (November 6, 2019): 8–19. http://dx.doi.org/10.29006/1564-2291.jor-2019.47(3).2.

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In this paper, on the basis of an analysis of the successive satellite optical images (MODISAqua, TIRS Landsat-8, AVHRR NOAA-18) and radar images (SAR-C Sentinel-1A, SAR-C Radarsat-2) on June 8–11, 2015, the effect of the mesoscale vortex movement (anticyclone with diameter of 35 km and associated cyclone) on the transport of oil spots in the northern part of the Gdansk Bay was demonstrated for the first time. The velocities of this transport are estimated; the observed picture of the movement of the spots is compared with their transfer according to the Seatrack Web model. The largest (about 20 cm/s) drift velocity corresponded to the spot that appeared near the periphery of the anticyclonic vortex (the region of maximum velocities), the smallest one was at the spot near the center of the vortex. At a wind speed of not more than 5 m/s on June 10 and an assumed orbital velocity of the anticyclone of the order of 20 cm/s, the contribution of the vortex motion to the total transport of the spots under the influence of wind and vortex should be decisive. The observed drift of the spots did not correspond to the forecast of their movement by the Seatrack Web numerical model, which did not take into account the vortex dynamics of the waters.

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Slysh, Vyacheslav I., Maxim A. Voronkov, Irina E. Val'tts, Victor Migenes, K. M. Shibata, Tomofumi Umemoto, and Makoto Inoue. "Space-VLBI observations of OH masers." Symposium - International Astronomical Union 206 (2002): 105–11. http://dx.doi.org/10.1017/s0074180900222171.

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We report on the first space-VLBI observations of the OH masers in two main-line OH transitions at 1665 and 1667 MHz. The observations involved the space radio telescope on board the Japanese satellite HALCA and an array of ground radio telescopes. The maps of the maser region and images of individual maser spots were produced with an angular resolution of 1 mas, which is several times higher than the angular resolution available on the ground. The maser spots were only partly resolved and a lower limit to the brightness temperature 6 × 1012 K was obtained. The masers seem to be located in the direction of low interstellar scattering.

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Hufford, Gary L., Herbert L. Kelley, Raymond K. Moore, and Jeffrey S. Cotterman. "Detection and growth of an Alaskan forest fire using GOES-9 3.9 µm imagery." International Journal of Wildland Fire 9, no. 2 (1999): 129. http://dx.doi.org/10.1071/wf00017.

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The utility of the new GOES-9 satellite 3.9 µm channel to monitor wildfires and their subsequent changes in growth and intensity in Alaska is examined. The June, 1996 Miller’s Reach forest fire is presented as a case study. Eighteen hours of sequential imagery coincident to the initiation and early stages of the fire are analyzed for hot spots. The dramatic response of the 3.9 µm channel to sub-pixel hot spots and the ability to access the data every 15 minutes makes the channel an effective tool to support forest fire management on wildfires in high latitudes to at least 61°N. In the case of Miller’s Reach, the fire was detected when it was less than 200 hectares in size. Changes in fire growth and intensity were also observed. An automated technique for decision makers which classifies hot spots without requiring image interpretation is proposed.

29

Belova, Yulia, Irina Razveeva, and Elena Rakhimbaeva. "Intelligent analysis of Earth remote sensing data on the distribution of phytoplankton and pollutants in coastal systems." E3S Web of Conferences 363 (2022): 02026. http://dx.doi.org/10.1051/e3sconf/202236302026.

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Currently, one of the topical areas of application of artificial intelligence methods in ensuring environmental monitoring of water resources is the analysis of Earth remote sensing images in order to control and prevent potentially dangerous changes in the environment. In the future, algorithms with elements of artificial intelligence form the basis of forecasting and decision-making systems. Systems for ensuring high-quality environmental monitoring can be improved using artificial intelligence methods, in particular, the development and application of special algorithms to prevent emergencies. The aim of the study is to develop an algorithm using artificial intelligence to detect spots of substances of various origins on the water surface. It has been established that the YOLOv4 convolutional neural network is applicable for high-quality detection of oil spots and bloom spots of phytoplankton populations. The developed algorithm was tested on real satellite images and showed an accuracy of 84-94%.

30

Pacheco, Carlos Eduardo, María Inmaculada Aguado, and Danilo Mollicone. "Identification and characterization of deforestation hot spots in Venezuela using MODIS satellite images." Acta Amazonica 44, no. 2 (June 2014): 185–96. http://dx.doi.org/10.1590/s0044-59672014000200004.

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Land cover changes over time as a result of human activity. Nowadays deforestation may be considered one of the main environmental problems. The objective of this study was to identify and characterize changes to forest cover in Venezuela between 2005-2010. Two maps of deforestation hot spots were generated on the basis of MODIS data, one using digital techniques and the other by means of direct visual interpretation by experts. These maps were validated against Landsat ETM+ images. The accuracy of the map obtained digitally was estimated by means of a confusion matrix. The overall accuracy of the maps obtained digitally was 92.5%. Expert opinions regarding the hot spots permitted the causes of deforestation to be identified. The main processes of deforestation were concentrated to the north of the Orinoco River, where 8.63% of the country's forests are located. In this region, some places registered an average annual forest change rate of between 0.72% and 2.95%, above the forest change rate for the country as a whole (0.61%). The main causes of deforestation for the period evaluated were agricultural and livestock activities (47.9%), particularly family subsistence farming and extensive farming which were carried out in 94% of the identified areas.

31

Steffke, Andrea M., and Andrew J. L. Harris. "A review of algorithms for detecting volcanic hot spots in satellite infrared data." Bulletin of Volcanology 73, no. 9 (May 6, 2011): 1109–37. http://dx.doi.org/10.1007/s00445-011-0487-7.

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32

Gürsoy, Ö., A. C. Birdal, F. Özyonar, and E. Kasaka. "Determining and Monitoring the Water Quality of Kizilirmak River of Turkey: First Results." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-7/W3 (April 30, 2015): 1469–74. http://dx.doi.org/10.5194/isprsarchives-xl-7-w3-1469-2015.

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Water resources are getting more and more important with each passing day in case of survival of humanity. For this reason, assessing water resources’ quality and also monitoring them have attracted lots of attention in the recent years. Remote sensing has been growing widely in the last decade and its resources are very usable when it comes to water resources management. In this study, by using remote sensing technology, satellite images that have 350 to 1050 nanometres wavelength band sensors (e.g. CHRIS Proba) are used to determine the quality of the Kizilirmak River’s water. Kizilirmak River is born and also pours out to sea in country limits of Turkey. It is the longest river of the country by the length of 1355 kilometres. Through the river’s resources, ground based spectral measurements are made to identify the quality differences of the water at the test spots that have been determined before. In this context at Imranli, where the river contacts civilization for the first time, which is located in Sivas city of Turkey, samples are gathered in order to do ground based spectroradiometer measurements. These samples are gathered simultaneously with the image acquiring time of CHRIS Proba satellite. Spectral signatures that are obtained from ground measurements are used as reference data in order to classify CHRIS Proba satellite’s hyperspectral images over the study area. Satellite images are classified based on Chemical Oxygen Demand (COD), Turbidity and Electrical Conductivity (EC) attributes. As a result, interpretations obtained from classified CHRIS Proba satellite hyperspectral images of the study area are presented.

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Ren, Chaofeng, Junfeng Xie, Xiaodong Zhi, Yun Yang, and Shuai Yang. "Laser Spot Center Location Method for Chinese Spaceborne GF-7 Footprint Camera." Sensors 20, no. 8 (April 18, 2020): 2319. http://dx.doi.org/10.3390/s20082319.

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The Gaofen-7 (GF-7) satellite is equipped with two area array sensor footprint cameras to capture the laser altimeter spot. In order to establish a direct correspondence between the laser data and the stereo image data, a new method is proposed to fit the center of the spot using the brightness difference between the spot image and the footprint image. First, the geometric registration between the spot image and the footprint image is completed based on feature matching or template matching. Then, the brightness values between the two images are extracted from the corresponding image position to form a measurement, and the least squares adjustment method is used to calculate the parameters of the brightness conversion model between the spot image and the footprint image. Finally, according to the registration relationship, the center of the identified spots is respectively positioned in the footprint images, so that the laser spots are accurately identified in the along-track stereo footprint images. The experimental results show that the spot error of this method is less than 0.7 pixel, which has higher reliability and stability, and can be used for a GF-7 satellite footprint camera.

34

Krestenitis, Marios, Georgios Orfanidis, Konstantinos Ioannidis, Konstantinos Avgerinakis, Stefanos Vrochidis, and Ioannis Kompatsiaris. "Oil Spill Identification from Satellite Images Using Deep Neural Networks." Remote Sensing 11, no. 15 (July 26, 2019): 1762. http://dx.doi.org/10.3390/rs11151762.

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Oil spill is considered one of the main threats to marine and coastal environments. Efficient monitoring and early identification of oil slicks are vital for the corresponding authorities to react expediently, confine the environmental pollution and avoid further damage. Synthetic aperture radar (SAR) sensors are commonly used for this objective due to their capability for operating efficiently regardless of the weather and illumination conditions. Black spots probably related to oil spills can be clearly captured by SAR sensors, yet their discrimination from look-alikes poses a challenging objective. A variety of different methods have been proposed to automatically detect and classify these dark spots. Most of them employ custom-made datasets posing results as non-comparable. Moreover, in most cases, a single label is assigned to the entire SAR image resulting in a difficulties when manipulating complex scenarios or extracting further information from the depicted content. To overcome these limitations, semantic segmentation with deep convolutional neural networks (DCNNs) is proposed as an efficient approach. Moreover, a publicly available SAR image dataset is introduced, aiming to consist a benchmark for future oil spill detection methods. The presented dataset is employed to review the performance of well-known DCNN segmentation models in the specific task. DeepLabv3+ presented the best performance, in terms of test set accuracy and related inference time. Furthermore, the complex nature of the specific problem, especially due to the challenging task of discriminating oil spills and look-alikes is discussed and illustrated, utilizing the introduced dataset. Results imply that DCNN segmentation models, trained and evaluated on the provided dataset, can be utilized to implement efficient oil spill detectors. Current work is expected to contribute significantly to the future research activity regarding oil spill identification and SAR image processing.

35

Bird, David, and John Barnard. "Magnetic Scattering in High-Energy Electron Diffraction." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 2 (August 12, 1990): 534–35. http://dx.doi.org/10.1017/s0424820100136271.

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Over the past 25 years or so, neutron diffraction has become the standard method of probing the internal magnetic structure of crystals. More recently, however, it has been found that x-ray magnetic scattering, although weak, can be observed using bright x-ray sources. The success of x-ray techniques leads one to wonder whether magnetic scattering might also be observed using electrons, and it is this question that is addressed here. Clearly, electrons are influenced by the internal magnetic fields of specimens_this is the basis of Lorentz microscopy of ferromagnetic domains. Here we examine scattering from more exotic forms of magnetic order, such as anti-ferromagnetism. The interesting point is that antiferromagnets have magnetic Bragg spots which appear between the basic lattice spots as the magnetic order sets in. Analysis of these spots forms the basis of neutron, and now x-ray, studies of magnetic structures. The extra ingredient that electrons might offer is that imaging in such spots could reveal the local magnetic structure including domains, dynamic effects etc., in just the same way that satellite dark-field imaging has contributed to studies of structural phase transitions.

36

Davies, Ashley Gerard, and Sylvain Douté. "Galileo NIMS Observations of Io." Highlights of Astronomy 12 (2002): 614–17. http://dx.doi.org/10.1017/s1539299600014398.

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AbstractThe Near Infrared Mapping Spectometer (NIMS) on the Galileo spacecraft has been observing the volcanic Jovian satellite Io at regular intervals since June 1996. These infrared observations have allowed detailed mapping of the distribution and grain size of sulfur dioxide on Io’s surface, identification of volcanic centers, mapping of the distribution of hot spots, and investigations into the style and evolution of individual volcanic eruptions.

37

Molchanov, O., A. Rozhnoi, M. Solovieva, O. Akentieva, J. J. Berthelier, M. Parrot, F. Lefeuvre, P. F. Biagi, L. Castellana, and M. Hayakawa. "Global diagnostics of the ionospheric perturbations related to the seismic activity using the VLF radio signals collected on the DEMETER satellite." Natural Hazards and Earth System Sciences 6, no. 5 (August 23, 2006): 745–53. http://dx.doi.org/10.5194/nhess-6-745-2006.

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Abstract. The analysis of the VLF signals radiated by ground transmitters and received on board of the French DEMETER satellite, reveals a drop of the signals (scattering spot) connected with the occurrence of large earthquakes. The extension of the "scattering spots" zone is large enough (1000–5000 km) and, probably, it increases with the magnitude of the "relative" earthquake. A possible model to explain the phenomenology, based on the acoustic gravity waves and the ionosphere turbulence, is proposed. The method of diagnostics applied to this study has the advantage to be a global one due to the world wide location of the powerful VLF transmitters and of the satellite reception. However, a specific disadvantage exists because the method requires rather a long time period of analysis due to the large longitudinal displacements among the successive satellite orbits. At the moment, at least, one month seems to be necessary.

38

Jiang, Shun Yao, Qin Xue Xiong, and Jian Qiang Zhu. "Evaluation of Lake Eutrophication Based on the HJ-1 Satellite Multispectral Data." Applied Mechanics and Materials 519-520 (February 2014): 1184–87. http://dx.doi.org/10.4028/www.scientific.net/amm.519-520.1184.

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Chinese domestic satellite HJ-1 was launched in 2008, now it has become a significant resource for environment monitoring because its Multispectral data are characterized by 2-day temporal resolution, 30 m spatial resolution and 700 km breadth. A study case was made that HJ-1 multispectral data were used for retrieving aggregative trophic level index (TLI()) of water body of lakes in Wuhan, China. The aim of this study is to evaluate the probability of HJ-1 Multispectral data on estimating the eutrophic level of inland water. At first, the TLI() of sampling spots of some lakes in Wuhan were calculated using the monitoring water quality data. In the mean time, the NDVI of corresponding spots were calculated from the HJ-1 multispectral data which had been taken radiometric calibration and geometric correction beforehand. After that, a remote sensing inversion model for TLI() had been built through linear regression using the NDVI as independent variables. Finally, the TLI() of all water bodies of Wuhan lakes were inversed with this model and a map for its spatial distribution was drawn up. Results demonstrated that there were good linear correlation relationships between the TLI() and NDVI of HJ-1 Multispectral data, and the distribution of inversed TLI() of the lakes accorded with the reality quite well. According to the above, an inference can be made that the methods to evaluate lakes eutrofication based on the HJ-1 satellite multispectral data may provide a cheap and rapid way for real-time monitoring and evaluation of lakes eutrophication.

39

Shakhvorostova, N. N., J. M. Moran, A. V. Alakoz, H. Imai, C. R. Gwinn, and A. M. Sobolev. "Fine structure and refractive scattering of the H₂O maser in star-forming region W49N." Proceedings of the International Astronomical Union 18, S380 (December 2022): 238–39. http://dx.doi.org/10.1017/s1743921323003460.

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AbstractWe used the unprecedented resolution of ∼25 μas of the VLBI array formed with the RadioAstron satellite to study the structures of H2O maser spots in the star forming region W49N. We found that anisotropic diffractive scattering of the ISM dominates the images of the maser spot, but does not completely blur them. The refractive scattering floor is about 0.001 in visibility at a baseline of 8 Gλ.

40

Lacava, Teodosio, Matthieu Kervyn, Mariangela Liuzzi, Francesco Marchese, Nicola Pergola, and Valerio Tramutoli. "Assessing Performance of the RSTVOLC Multi-Temporal Algorithm in Detecting Subtle Hot Spots at Oldoinyo Lengai (Tanzania, Africa) for Comparison with MODLEN." Remote Sensing 10, no. 8 (July 25, 2018): 1177. http://dx.doi.org/10.3390/rs10081177.

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The identification of subtle thermal anomalies (i.e., of low-temperature and/or spatial extent) at volcanoes by satellite is of great interest for scientists, especially because minor changes in surface temperature might reveal an unrest phase or impending activity. A good test case for assessing the sensitivity level of satellite-based methods is to study the thermal activity of Oldoinyo Lengai (OL) (Africa, Tanzania), which is the only volcano on Earth emitting natrocarbonatite lavas at a lower temperature (i.e., in the range 500–600 °C) than usual magmatic surfaces. In this work, we assess the potential of the RSTVOLC multi-temporal algorithm in detecting subtle hot spots at OL for comparison with MODLEN: A thermal anomaly detection method tailored to OL local conditions, by using Moderate Resolution Imaging Spectroradiometer (MODIS) data. Our results investigating the eruptive events of 2000–2008 using RSTVOLC reveal the occurrence of several undocumented thermal activities of OL, and may successfully integrate MODLEN observations. In spite of some known limitations strongly affecting the identification of volcanic thermal anomalies from space (e.g., cloud cover; occurrence of short-lived events), this work demonstrates that RSTVOLC may provide a very important contribution for monitoring the OL, identifying subtle hot spots showing values of the radiant flux even around 1 MW.

41

Brieβ, K., H. Jahn, and H. P. Röser. "A DLR small satellite mission for the investigation of hot spots, vegetation and clouds." Acta Astronautica 39, no. 9-12 (November 1996): 899–908. http://dx.doi.org/10.1016/s0094-5765(97)00074-x.

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42

Costa, Bibiana Salvador Cabral da, and Eliana Lima da Fonseca. "The Use of Fire Radiative Power to Estimate the Biomass Consumption Coefficient for Temperate Grasslands in the Atlantic Forest Biome." Revista Brasileira de Meteorologia 32, no. 2 (June 2017): 255–60. http://dx.doi.org/10.1590/0102-77863220004.

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Abstract Every year, many active fire spots are identified in the satellite images of the southern Brazilian grasslands in the Atlantic Forest biome and Pampa biome. Fire Radiative Power (FRP) is a technique that uses remotely sensed data to quantify burned biomass. FRP measures the radiant energy released per time unit by burning vegetation. This study aims to use satellite and field data to estimate the biomass consumption rate and the biomass consumption coefficient for the southern Brazilian grasslands. Three fire points were identified in satellite FRP products. These data were combined with field data, collected through literature review, to calculate the biomass consumption coefficient. The type of vegetation is an important variable in the estimation of the biomass consumption coefficient. The biomass consumption rate was estimated to be 2.237 kg s-1 for the southern Brazilian grasslands in Atlantic Forest biome, and the biomass consumption coefficient was estimated to be 0.242 kg MJ-1.

43

Grigoraș, Georgiana, and Bogdan Urițescu. "Spatial Hotspot Analysis of Bucharest’s Urban Heat Island (UHI) Using Modis Data." Annals of Valahia University of Targoviste, Geographical Series 18, no. 1 (April 1, 2018): 14–22. http://dx.doi.org/10.2478/avutgs-2018-0002.

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Abstract The aim of the study is to find the relationship between the land surface temperature and air temperature and to determine the hot spots in the urban area of Bucharest, the capital of Romania. The analysis was based on images from both moderate-resolution imaging spectroradiometer (MODIS), located on both Terra and Aqua platforms, as well as on data recorded by the four automatic weather stations existing in the endowment of The National Air Quality Monitoring Network, from the summer of 2017. Correlation coefficients between land surface temperature and air temperature were higher at night (0.8-0.87) and slightly lower during the day (0.71-0.77). After the validation of satellite data with in-situ temperature measurements, the hot spots in the metropolitan area of Bucharest were identified using Getis-Ord spatial statistics analysis. It has been achieved that the “very hot” areas are grouped in the center of the city and along the main traffic streets and dense residential areas. During the day the "very hot spots” represent 33.2% of the city's surface, and during the night 31.6%. The area where the mentioned spots persist, falls into the "very hot spot" category both day and night, it represents 27.1% of the city’s surface and it is mainly represented by the city center.

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Somolinos, Florencio, González, and Cátedra. "Multi-Beam Circular Polarized Reflectarray on Parabolic Reflector by Variable Rotation Technique." Applied Sciences 9, no. 13 (June 29, 2019): 2659. http://dx.doi.org/10.3390/app9132659.

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Multi-beams antennas are currently being used for direct broadcast satellite, personal communication satellite, military communication satellite, and high-speed internet applications. In this work, a circularly polarized (CP) multi-spot beam satellite parabolic reflectarray antenna is designed to provide six spot beams at 19.7 GHz. For this purpose, an easy technique to compute the required phase shifts to produce two focused beams in specular directions for a CP parabolic reflectarray is proposed. These required phase shifts are added to the reflected fields by the variable rotation of the reflectarray elements printed on the surface of a parabolic antenna which are fed by a dual-CP feed-horn. For this purpose, a reflectarray cell made of a conductive cross embedded in a grounded multilayered substrate is optimized to produce very linear phase-shift and low cross-polarization level. To demonstrate the multibeam capacity, a 1.8-meter offset parabolic reflectarray made of the optimized reflectarray element was designed to generate six focused beams in dual-CP with three dual-CP feed-horns. The six main spots fulfill the typical multi spot satellite requirement with angular separation less than 0.56°, 0.4 dB loss in the gain, and cross-polarization level below 35 dB with respect to the maximum of radiation.

45

Corradino, Claudia, Eleonora Amato, Federica Torrisi, and Ciro Del Negro. "Data-Driven Random Forest Models for Detecting Volcanic Hot Spots in Sentinel-2 MSI Images." Remote Sensing 14, no. 17 (September 2, 2022): 4370. http://dx.doi.org/10.3390/rs14174370.

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Volcanic thermal anomalies are monitored with an increased application of optical satellite sensors to improve the ability to identify renewed volcanic activity. Hotspot detection algorithms adopting a fixed threshold are widely used to detect thermal anomalies with a minimal occurrence of false alerts. However, when used on a global scale, these algorithms miss some subtle thermal anomalies that occur. Analyzing satellite data sources with machine learning (ML) algorithms has been shown to be efficient in extracting volcanic thermal features. Here, a data-driven algorithm is developed in Google Earth Engine (GEE) to map thermal anomalies associated with lava flows that erupted recently at different volcanoes around the world (e.g., Etna, Cumbre Vieja, Geldingadalir, Pacaya, and Stromboli). We used high spatial resolution images acquired by a Sentinel-2 MultiSpectral Instrument (MSI) and a random forest model, which avoids the setting of fixed a priori thresholds. The results indicate that the model achieves better performance than traditional approaches with good generalization capabilities and high sensitivity to less intense volcanic thermal anomalies. We found that this model is sufficiently robust to be successfully used with new eruptive scenes never seen before on a global scale.

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Jacobson, Abram R., Robert H. Holzworth, Michael P. McCarthy, and Robert F. Pfaff. "Initial Studies with the Lightning Detector on the C/NOFS Satellite, and Cross Validation with WWLLN." Journal of Atmospheric and Oceanic Technology 28, no. 11 (November 1, 2011): 1423–35. http://dx.doi.org/10.1175/jtech-d-11-00047.1.

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Abstract The lightning detector (LD) on the Communications/Navigation Outage Forecast System (C/NOFS) satellite uses a pair of silicon photodiodes, viewing each flank at right angles to the satellite track over an extended field of view. The data product is a report every ½ s of the number of digitizer cycles (125 μs each) for which the detected power was in predefined ranges. The performance of this system over the first 2.5 years of the C/NOFS mission is discussed, statistics of its lightning observations are presented, and a statistical cross validation using the World-Wide Lightning Location Network (WWLLN) as a ground truth is provided. It is found that the LD reports of lightning, despite their blunt timing (½ s), show correlation with strokes detected and located by WWLLN. The irradiance of these strokes lies on the high-power flank of the irradiance distribution seen earlier by the FORTE satellite. Thus, the LD thresholds favor high-power lightning; it is shown that the closest portion of the field of view is more likely to provide WWLLN coincidences than is the furthest portion of the field of view. Statistics of lightning incidence are examined at low latitudes, versus longitude, and distributions that are consistent with those established earlier by the OTD and LIS instruments are retrieved. Finally, the longitude dependence of the irradiance per stroke is examined and the ways in which it differs between the three major lightning “hot spots” is explored. It is observed that the radiance per stroke over the Congo Basin is lower than that over the other two hot spots (Maritime Continent/South Asia and the Americas), consistent with earlier observations by the OTD imager.

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Fricker, Helen Amanda, Ted Scambos, Sasha Carter, Curt Davis, Terry Haran, and Ian Joughin. "Synthesizing multiple remote-sensing techniques for subglacial hydrologic mapping: application to a lake system beneath MacAyeal Ice Stream, West Antarctica." Journal of Glaciology 56, no. 196 (2010): 187–99. http://dx.doi.org/10.3189/002214310791968557.

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AbstractWe present an analysis of the active hydrologic system of MacAyeal Ice Stream (MacIS), West Antarctica, from a synthesis of multiple remote-sensing techniques: satellite laser altimetry; satellite image differencing; and hydrologic potential mapping (using a satellite-derived DEM and a bedrock DEM from airborne radio-echo sounding). Combining these techniques augments the information provided by each one individually, and allows us to develop a protocol for studying subglacial hydrologic systems in a holistic manner. Our study reveals five large active subglacial lakes under MacIS, the largest of which undergoes volume changes of at least 1.0 km3. We discuss the hydrologic properties of this system and present evidence for links between the lakes. At least three of the lakes are co-located with sticky spots, i.e. regions of high local basal shear stress. We also find evidence for surface elevation changes due to ice-dynamic effects (not just water movement) caused by changes in basal resistance. Lastly, we show that satellite radar altimetry is of limited use for monitoring lake activity on fast-flowing ice streams with surfaces that undulate on ∼10 km length scales.

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Koen, C. "Can complex T Tauri star light curves be modelled with star-spots?" Monthly Notices of the Royal Astronomical Society 500, no. 1 (October 29, 2020): 1366–79. http://dx.doi.org/10.1093/mnras/staa3347.

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ABSTRACT ‘Transiting Exoplanet Survey Satellite’ photometry of 10 young stars with very complex periodic light curves is considered. Previous findings that these cannot be due to dark surface spots are re-evaluated by allowing arbitrarily shaped areas on the stellar surface to have sub-photospheric fluxes. This is done by approximating flux integrals by sums over surface elements. The unknown ratios of spot to photospheric fluxes are determined by lasso or ridge regression procedures. It is found that almost all light curves can be modelled very accurately in this way. The usual, if rarely stated, caveat applies – star-spot models presented in the paper are not unique.

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Seeberg, Gereon, Antonia Hostlowsky, Julia Huber, Julia Kamm, Lucia Lincke, and Clemens Schwingshackl. "Evaluating the Potential of Landsat Satellite Data to Monitor the Effectiveness of Measures to Mitigate Urban Heat Islands: A Case Study for Stuttgart (Germany)." Urban Science 6, no. 4 (November 9, 2022): 82. http://dx.doi.org/10.3390/urbansci6040082.

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The urban heat island (UHI) effect is a serious health risk for people living in cities and thus calls for effective mitigation strategies in urban areas. Satellite data enable monitoring of the surface urban heat island (SUHI) over large areas at high spatial resolution. Here we analysed SUHI in the city of Stuttgart (Germany) based on land surface temperature (LST) data from Landsat at 30 m resolution. The overall SUHI in Stuttgart decreased by 1.4 °C between the investigated time periods 2004–2008 and 2016–2020, while the absolute LST increased by 2.5 °C. We identified local hotspots of strong warming and cooling in Stuttgart through the change in SUHI and categorised them based on the predominant land cover change occurring at the hotspot using the Normalised Difference Vegetation Index (NDVI) from Landsat as well as visual information on land cover changes from Google Earth Pro. The establishment of green roofs, as well as albedo changes, are predominantly responsible for cooling spots, while warming spots are mostly associated with the sealing of surfaces. This highlights that vegetation has a dominant influence on SUHI development in Stuttgart. Combining satellite-based LST data with visual information thus provides an effective method to identify local warming and cooling hotspots, which allows monitoring of the success of city policies against heat stress and guides future policy.

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Asiedu, Ebenezer, John Manyimadin Kusimi, Emmanuel Nartey Pinto, Clifford Semabiah, and Emmanuel Morgan Attua. "Studying Bankline Migration of the Lower Pra Basin using Remote Sensing and GIS." Ghana Journal of Geography 15, no. 2 (July 26, 2023): 88–109. http://dx.doi.org/10.4314/gjg.v15i2.4.

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The study investigated bank erosion and accretion of the lower section of the Pra River of Ghana using a topographical map of 1974 and satellite imagery of 2007, 2015, and 2018 which was augmented by field observation and key informant interviews. Bankline changes due to erosion and accretion and the total volumetric change in river channel were measured using Remote Sensing and Geographic Information System approaches. The study showed that erosion was more pronounced in both the right and left bank as compared to accretion. The study revealed that bank width area of the lower basin of Pra River increased by 50.7 m² from 16.2 m² in 1974 to 66.9 m² in 2018 eroding large portions of land along the right and left banks of the river. In general, the number of erosional spots in selected cross sections exceeded that of deposition. Erosion took place in 13 spots out of 20 spots constituting 65% with a rate ranging between 0.2 and 3.4 m/year. This research showed the value of channel morphological analysis as it brought to the fore, a quantitative perspective to bank erosion and accretion processes of fluvial systems.

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