Jovian auroral conductance from Juno-UVS: hemispheric asymmetry?

2020 ◽  
Author(s):  
Jean-Claude Gérard ◽  
Leonardos Gkouvelis ◽  
Bertrand Bonfond ◽  
Randy Gladstone ◽  
Michel Blanc ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Electrical Coupling ◽  
Auroral Oval ◽  
Space Science ◽  
Geophysical Research ◽  
Characteristic Energy ◽  
Density Maps ◽  
State Densities ◽  
Ion Species ◽  
Juno Mission

<p>Ionospheric conductance is important in controlling the electrical coupling between the Jovian planetary magnetosphere and its ionosphere. To some extent, it regulates the characteristics of the ionospheric current from above and the closure of the magnetosphere-ionosphere circuit in the ionosphere (Cowley&Bunce, 2001). Multi-spectral images collected with the UltraViolet Spectrograph (UVS) (Gladstone et al., 2017) on board Juno (Bagenal et al.,2017) have been analyzed to derive the spatial distribution of the auroral precipitation reaching the atmosphere (Bonfond et al., 2017). Electron energy flux and their characteristic energy have been used as inputs to an ionospheric model providing the production and loss rates of the main ion species, H<sub>3</sub><sup>+</sup>, hydrocarbon ions and electrons (Gérard et al., 2020). Their steady state densities are calculated and used to determine the local distribution of the Pedersen electrical conductivity and its altitude integrated value for each UVS pixel. These values are displayed as H<sub>3</sub><sup>+</sup> density and Pedersen conductivity maps. We find that the main contribution to the Pedersen conductance corresponds to collisions of H<sub>3</sub><sup>+</sup> and hydrocarbon ions with H<sub>2</sub>.</p><p>Analysis of the Birkeland current intensities based on the Juno magnetometers measurements (Kotsiaros et al. 2019) indicated that the observed current intensities are statistically larger in the south. They suggested that these differences are possibly due to a higher Pedersen conductance in this hemisphere. In order to verify this hypothesis, we calculate the conductance and H<sub>3</sub><sup>+</sup> density maps for perijoves 1 to 15 based on Juno-UVS spectral images. We compare the spatially integrated auroral conductance values of the two hemispheres for each orbit.  The objective is to identify possible hemispheric asymmetries.   </p><p>REFERENCES</p><p>Bagenal, F., et al. (2017). Magnetospheric science objectives of the Juno mission. Space Science Reviews, 213(1-4), 219-287.</p><p>Bonfond, B., et al. (2017). Morphology of the UV aurorae Jupiter during Juno's first perijove observations. Geophysical Research Letters, 44(10), 4463-4471.</p><p>Cowley, S.W.H. & Bunce, E.J. (2001). Origin of the main auroral oval in Jupiter’s coupled magnetosphere–ionosphere system. Planet. Space Sci. 49, 1067–1088.</p><p>Gérard et al., Spatial distribution of the Pedersen conductance in the Jovian aurora from Juno-UVS spectral images, J. Geophys. Res., in press.</p><p>Gladstone et al. (2017). The ultraviolet spectrograph on NASA’s Juno mission. Space Science Reviews, 213(1-4), 447-473.</p><p>Kotsiaros, S. et al. (2019). Birkeland currents in Jupiter’s magnetosphere observed by the polar-orbiting Juno spacecraft. Nature Astronomy, 3(10), 904-909.</p>

scholarly journals Spatial distribution of schistosomiasis and geohelminthiasis cases in the rural areas of Pernambuco, Brazil

2012 ◽  
Vol 45 (5) ◽  
pp. 633-638 ◽  
Author(s):  
Verônica Santos Barbosa ◽  
Karina Conceição Araújo ◽  
Onicio Batista Leal Neto ◽  
Constança Simões Barbosa
Keyword(s):  
Spatial Distribution ◽  
Rural Areas ◽  
Public Health Problem ◽  
Secondary Data ◽  
Kernel Estimator ◽  
Distribution Patterns ◽  
Number Of Children ◽  
Density Maps ◽  
Significant Public Health Problem ◽  
Significant Public Health

INTRODUCTION: The prevalence and intensity of geohelminth infections and schistosomiasis remain high in the rural areas of Zona da Mata, Pernambuco (ZMP), Brazil, where these parasites still represent a significant public health problem. The present study aimed to spatially assess the occurrences of schistosomiasis and geohelminthiasis in the ZMP. METHODS: The ZMP has a population of 1,132,544 inhabitants, formed by 43 municipalities. An ecological study was conducted, using secondary data relating to positive human cases and parasite loads of schistosomiasis and positive human cases of geohelminthiasis that were worked up in Excel 2007. We used the coordinates of the municipal headquarters to represent the cities which served as the unit of analysis of this study. The Kernel estimator was used to spatially analyze the data and identify distribution patterns and case densities, with analysis done in ArcGIS software. RESULTS: Spatial analysis from the Kernel intensity estimator made it possible to construct density maps showing that the northern ZMP was the region with the greatest number of children infected with parasites and the populations most intensely infected by Schistosoma mansoni. In relation to geohelminths, there was higher spatial distribution of cases of Ascaris lumbricoides and Trichuris trichiura in the southern ZMP, and greater occurrence of hookworms in the northern/central ZMP. CONCLUSIONS: Despite several surveys and studies showing occurrences of schistosomiasis and geohelminthiasis in the ZMP, no preventive measures that are known to have been effective in decreasing these health hazards have yet been implemented in the endemic area.

scholarly journals Correspondence between the ULF wave power spatial distribution and auroral oval boundaries

2016 ◽  
Vol 2 (2) ◽  
pp. 46-65 ◽  
Author(s):  
Ольга Козырева ◽  
Olga Kozyreva ◽  
Вячеслав Пилипенко ◽  
Vyacheslav Pilipenko ◽  
Марк Энгебретсон ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Spectral Power ◽  
Recovery Phase ◽  
Temporal Variations ◽  
Auroral Oval ◽  
Wave Power ◽  
Observational Result ◽  
Equatorward Boundary ◽  
Image Satellite ◽  
Magnetospheric Field

The world-wide spatial distribution of the wave power in the Pc5 band during magnetic storms has been compared with auroral oval boundaries. The poleward and equatorward auroral oval boundaries are estimated using either the British Antarctic Survey database containing IMAGE satellite UV observations of the aurora or the OVATION model based on the DMSP particle data. The “epicenter” of the spectral power of broadband Pc5 fluctuations during the storm growth phase is mapped inside the auroral oval. During the storm recovery phase, the spectral power of narrowband Pc5 waves, both in the dawn and dusk sectors, is mapped inside the auroral oval or around its equatorward boundary. This observational result confirms previously reported effects: the spatial/temporal variations of the Pc5 wave power in the morning/pre-noon sector are closely related to the dynamics of the auroral electrojet and magnetospheric field-aligned currents. At the same time, narrowband Pc5 waves demonstrate typical resonant features in the amplitude-phase latitudinal structure. Thus, the location of the auroral oval or its equatorward boundary is the preferred latitude for magnetospheric field-line Alfven resonator excitation. This effect is not taken into account by modern theories of ULF Pc5 waves, but it could be significant for the development of more adequate models.

Compositional Indicators for a Dynamical Barrier within Saturn’s E-ring

2021 ◽  
Author(s):  
Lenz Nölle ◽  
Frank Postberg ◽  
Sascha Kempf ◽  
Jon Hillier ◽  
Nozair Khawaja ◽  
...  
Keyword(s):  
Salt Concentration ◽  
Mass Spectra ◽  
Space Science ◽  
Cosmic Dust ◽  
Dust Particles ◽  
Equilibrium Potential ◽  
Surface Charges ◽  
Geophysical Research ◽  
Water Ice ◽  
Plasma Sputtering

<p><strong>Abstract</strong></p> <p>Mass spectra from the Cosmic Dust Analyzer (CDA) [1] onboard the Cassini spacecraft revealed the existence of different compositional types of icy dust particles in Saturn’s E-ring. Most of these µm to sub-µm water ice grains were ejected from the cryo-volcanoes at the southern polar region of Enceladus and carry different constituents, for example organic compounds or salts [2-5]. These particles are subject to ongoing plasma sputtering during their lifetime in the E-ring [6,7].</p> <p>Recent modelling of the dynamics of E-ring particles has shown that, in the region between the orbital distances of Dione and Rhea, the outwards migration of a proportion of the E-ring dust slows down and almost comes to a halt [8]. Due to the minimum of the V-shaped electrostatic grain equilibrium potential [9] and a polarity reversal of the dust surface charges [10], the semi-major axes of the dust particles’ orbits actually stop growing, forcing the particles to spend a significant part of their lifetime at this distance from Saturn. Therefore, this phenomenon should allow plasma sputtering to operate much longer on the dust particles residing in this region, potentially resulting in detectable alterations to the dust particle properties, e.g. particle composition and size, in this region.</p> <p>Here we present the discovery of a new population of grains within the E ring, which show signs of compositional alteration, best explained by plasma sputtering. The radial frequency distribution of these grains shows a distinct accumulation in the region between the orbits of Dione and Rhea, and may provide evidence of prolonged residence there. Analyses of CDA mass spectra of the grains, interpreted via comparison with laboratory Laser‐Induced Liquid Beam Ion Desorption (LILBID) [11] analogue experiments, indicate the particles to be very salt-rich water ice. In comparison to the previously reported salt-rich particle types, generated from Enceladus’ subsurface ocean [3,4] this new population must possess a far higher salt concentration to explain its observed spectral appearance. We propose that the increase in salt concentration arises from sputtering-induced removal of water from less salty oceanic grains (Type 3) [3,4], during their extended time in the region between Dione and Rhea. This population may therefore represent the first confirmation of the proposed dynamical barrier within Saturn’s E-ring.</p> <p><strong>References</strong></p> <p>[1] Srama, R. et al., The Cassini Cosmic Dust Analyzer, Space Science Reviews, 114, 465-518, 2004.</p> <p>[2] Hillier, J. et al., The composition of Saturn’s E ring, Mon. Not. R. Astron. Soc., 377, 1588–1596, 2007</p> <p>[3] Postberg, F. et al., The E-ring in the vicinity of Enceladus II. Probing the moon’s interior-The composition of E-ring particles, Icarus, 193, 438-454, 2008.</p> <p>[4] Postberg, F. et al., Sodium salts in E-ring ice grains from an ocean below the surface of Enceladus, Nature, 459, 1098-1101, 2009.</p> <p>[5] Postberg, F. et al., A salt-water reservoir as the source of a compositionally stratified plume on Enceladus, Nature, 474, 620–622, 2011</p> <p>[6] Jurac, S. et al., Saturn’s E Ring and Production of the Neutral Torus, Icarus, 149, 384–396, 2001</p> <p>[7] Johnson, R. E. et al., Sputtering of ice grains and icy satellites in Saturn’s inner magnetosphere, Planetary and Space Science, 56, 1238–1243, 2008</p> <p>[8] Kempf & Beckmann, Dynamics and long-term evolution of Saturn's E ring particles (in prep.)</p> <p>[9] Mitchell, C. J. et al., Tenuous ring formation by the capture of interplanetary dust at Saturn, JOURNAL OF GEOPHYSICAL RESEARCH, 110, 2005</p> <p>[10] Kempf, S. et al., The electrostatic potential of E ring particles, Planetary and Space Science, 54, 999-1006, 2006</p> <p>[11] Klenner, F. et al., Analogue spectra for impact ionization mass spectra of water ice grains obtained at different impact speeds in space, Rapid Commun Mass Spectrom., 33, 1751–1760, 2019</p>

scholarly journals Tracking ground state Ba+ions in an expanding laser–plasma plume using time-resolved vacuum ultraviolet photoionization imaging

2004 ◽  
Vol 22 (3) ◽  
pp. 207-213 ◽  
Author(s):  
J.S. HIRSCH ◽  
K.D. KAVANAGH ◽  
E.T. KENNEDY ◽  
J.T. COSTELLO ◽  
P. NICOLOSI ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Laser Plasma ◽  
Ground State ◽  
Column Density ◽  
Vacuum Ultraviolet ◽  
Plasma Plume ◽  
Experimental System ◽  
Time Resolved ◽  
Density Maps ◽  
Ccd Array

We report results from a study of the integrated column density and expansion dynamics of ground-state-selected Ba+ions in a laser–plasma plume using a new experimental system—VPIF (vacuum-ultraviolet photoabsorption imaging facility). The ions are tracked by recording the attenuation of a pulsed and collimated vacuum ultraviolet beam, tuned to the 5p–6dinner-shell resonance of singly ionized barium, as the expanding plasma plume moves across it. The attenuated beam is allowed to fall on a CCD array where the spatial distribution of the absorption is recorded. Time-resolved ion velocity and integrated column density maps are readily extracted from the photoionization images.

scholarly journals Hierarchical star formation in nearby galaxies

2020 ◽  
Vol 644 ◽  
pp. A101
Author(s):  
M. J. Rodríguez ◽  
G. Baume ◽  
C. Feinstein
Keyword(s):  
Spatial Distribution ◽  
Star Formation ◽  
Luminosity Function ◽  
Young Stars ◽  
Young Population ◽  
Star Forming ◽  
Density Maps ◽  
The Galaxy ◽  
Nearby Galaxies ◽  
Internal Distribution

Aims. The purpose of this work is to study the properties of the spatial distribution of the young population in three nearby galaxies in order to better understand the first stages of star formation. Methods. We used ACS/HST photometry and the “path-linkage criterion” in order to obtain a catalog of young stellar groups (YSGs) in the galaxy NGC 2403. We studied the internal distribution of stars in these YSGs using the Q parameter. We extended these analyses to the YSGs detected in in NGC 300 and NGC 253 our previous works. We built the young stars’ density maps for these three galaxies. Through these maps, we were able to identify and study young stellar structures on larger scales. Results. We found 573 YSGs in the galaxy NGC 2403, for which we derived their individual sizes, densities, luminosity function, and other fundamental characteristics. We find that the vast majority of the YSGs in NGC 2403, NGC 300 and NGC 253 present inner clumpings, following the same hierarchical behavior that we observed in the young stellar structures on larger scales in these galaxies. We derived values of the fractal dimension for these structures between ∼1.5 and 1.6. These values are very similar to those obtained in other star forming galaxies and in the interstellar medium, suggesting that the star formation process is regulated by supersonic turbulence.

The Application of GPS Visitor Tracking Implications for Interpretation at Heritage Sites

2019 ◽  
Vol 24 (1) ◽  
pp. 93-98
Author(s):  
Ryan L. Sharp ◽  
Ted T. Cable ◽  
Aubrey Burns
Keyword(s):  
Spatial Distribution ◽  
Temporal And Spatial Distribution ◽  
Heritage Sites ◽  
Rate Analysis ◽  
Point Of Interest ◽  
Points Of Interest ◽  
Heritage Site ◽  
Density Maps ◽  
Temporal And Spatial ◽  
Visitor Center

This paper presents the results of the application of GPS Visitor Tracking (GVT) to evaluate visitor movements through a heritage site. This method provides temporal and spatial distribution and “heat maps” that depict visitor movements through the site. Documenting these visitor movements indicates to interpreters where to concentrate interpretive efforts and identifies opportunities to strategically encourage visitation to less visited areas of the site. The research team approached 117 travel parties and 106 elected to participate in the study, yielding a 90.6% response rate. Analysis revealed that visitors typically travel in a clockwise direction once they entered the park, stopping at a point of interest then proceeding to the visitor center. However, the density maps revealed that other points of interest were less visited. This information about temporal and spatial distribution of visitors can provide information for creating interpretive programs that people may engage with at the park.

The seismicity of Mars, as catalogued by InSight’s Marsquake Service

2021 ◽  
Author(s):  
Nikolaj Dahmen ◽  
Keyword(s):  
Seismic Data ◽  
Low Frequency ◽  
Signal Amplitude ◽  
Space Science ◽  
Atmospheric Conditions ◽  
Geophysical Research ◽  
Moment Tensors ◽  
Event Location ◽  
Strong Winds ◽  
Core Mission

<p>NASA’s InSight lander continues to record high-quality seismic data from the surface of Mars two and a half years after landing [1,7,9]. The data collected by the SEIS seismometer package [8] are routinely monitored by the Marsquake Service (MQS) [4,5], a core mission service that is tasked with curating the Martian seismicity catalogue. To date, more than 500 distant marsquakes have been identified, which can be classified by their frequency content into high- and low- frequency event families [4,7,10]. In addition, the catalogue includes over 800 short-duration events potentially associated with local thermal cracking [6]. The local atmospheric conditions have a strong influence on the seismic noise level, which varies from levels below pre-mission expectation during the evening, to high-noise levels during the day owing to strong winds and atmospheric turbulence. Due to the low signal amplitude of the marsquakes, their detection is mainly restricted to evenings and nights with low to moderate winds. Following the marsquake detection and discrimination from atmospherically-induced energy, MQS identifies crustal and body phase arrivals and proposes a distance based on the travel time differences. Only a handful of low-frequency marsquakes have a clear polarized arrival that allows MQS to determine the backazimuth and hence provide an event location. Deep into the second Martian season of continuous seismic observation, we provide an update on the recent seismicity and the seasonally repeating features of the dataset. This includes an overview of MQS’ procedures of monitoring the seismic dataset and the different marsquake types observed, as well as a review of event location, magnitude [2], moment tensors [3] and possible seismic sources.</p> <p>References:</p> <p>[1] Banerdt, W. Bruce, et al. "Initial results from the InSight mission on Mars." <em>Nature Geoscience</em> 13.3 (2020): 183-189.</p> <p>[2] Böse, Maren, et al. "Magnitude Scales for Marsquakes Calibrated from InSight Data." <em>Bulletin of the Seismological Society of America</em> (2021).</p> <p>[3] Brinkman, Nienke, et al. "First focal mechanisms of marsquakes." <em>Journal of Geophysical Research: Planets</em> 126.4 (2021): e2020JE006546</p> <p>[4] Clinton, John, et al. "The Marsquake catalogue from InSight, sols 0–478." <em>Physics of the Earth and Planetary Interiors</em> 310 (2021): 106595.</p> <p>[5] Clinton, John, et al. "The Marsquake service: Securing daily analysis of SEIS data and building the Martian seismicity catalogue for InSight." <em>Space Science Reviews</em> 214.8 (2018): 1-33.</p> <p>[6] Dahmen, Nikolaj, et al. "Super high frequency events: a new class of events recorded by the InSight seismometers on Mars." <em>Journal of Geophysical Research: Planets</em> 126.2 (2021): e2020JE006599.</p> <p>[7] Giardini, Domenico, et al. "The seismicity of Mars." <em>Nature Geoscience</em> 13.3 (2020): 205-212.</p> <p>[8] Lognonné, Philippe, et al. "SEIS: Insight’s seismic experiment for internal structure of Mars." <em>Space Science Reviews</em> 215.1 (2019).</p> <p>[9] Lognonné, Philippe, et al. "Constraints on the shallow elastic and anelastic structure of Mars from InSight seismic data." <em>Nature Geoscience</em> 13.3 (2020): 213-220.</p> <p>[10] van Driel, Martin, et al. "High‐Frequency Seismic Events on Mars Observed by InSight." <em>Journal of Geophysical Research: Planets</em> 126.2 (2021): e2020JE006670.</p>

Inclusion of scientific algorithms in MATISSE

2020 ◽  
Author(s):  
Edoardo Rognini ◽  
Angelo Zinzi ◽  
Davide Grassi ◽  
Alberto Adriani ◽  
Alessandro Mura ◽  
...  
Keyword(s):  
Hyperspectral Image ◽  
Three Dimensional ◽  
Space Science ◽  
Physical Parameters ◽  
Temperature Dependent ◽  
Geophysical Research ◽  
Heterogeneous Architectures ◽  
Thermophysical Modeling ◽  
Solar System Exploration ◽  
Advanced Tool

<p>MATISSE (Multi-purpose Advanced Tool for the Solar System Exploration) [1] is a tool that allows the visualization of observations from space missions and datasets derived from these observations on  a  three-dimensional  model  of  the  selected  target  body.  The  second  version  of  the  tool  (named MATISSE  2.0 –https://tools.ssdc.asi.it/Matisse)  will,  among  other  things,  include  algorithms developed  by  partner  research  teams;  in  this  work  we  focalize  our  attention  on  the  MATISSE inclusion of two codes developed for atmospheric retrieval and thermophysical modeling. The retrieval code is used for the analysis of the spectra provided by the JIRAM instrument (Jovian Infrared Auroral Mapper [2]) onboard the NASA’s Juno mission, whose main purpose is the study of the upper regions of Jupiter’s atmosphere in the 2-5 μm wavelength range and pressure up to 5-7 bar. The spectra provided by the instrument are processed with the retrieval code that calculates, for each pixel of a hyperspectral image, the chemical and physical parameters in the corresponding points of the  atmosphere  [3].  The  code  processes  all  pixels  of  a  hyperspectral  image,  so  parallelization  is convenient  in  order  to  reduce  the  computation  time;  this  is  possible  by  using  the  Python  language tools, which allow the execution of a code written in its own language (FORTRAN in this case) by providing  the  required  parallelization. As a further optimization step,  the  code has been converted into a Docker image to make it portable and easy to run on heterogeneous architectures. The second  code  included  in  MATISSE  is  a  thermophysical  model  that  calculates  the  surface temperature of airless bodies as function of thermal conductivity [4,5] and other physical properties; the calculated temperature can be compared with the measured ones, if any, in order to retrieve the thermal properties of the soil, or can be used to compute other temperature-dependent quantities. At the present time this code is going to be used for Mercury and Ceres and is almost ready to be included in MATISSE 2.0.</p> <p>[1] Zinzi, A., et al. (2016), Astronomy & Computing, 15, 16-28<br />[2] Adriani, A., et al. (2017), Space Science Reviews, 213, 393-446<br />[3] Grassi et al. (2010), Planetary and Space Science, 58, 1265-1278<br />[4] Capria, M. T. et al (2014), Geophysical Research Letters, 41, 1438-1443<br />[5] Rognini et al. (2019), Journal of Geophysical Research, https://doi.org/10.1029/2018JE005733</p>

Change in Spatial Distribution of State Densities of Carbon Nanotubes Under Anisotropic Strain Field

2014 ◽  
Author(s):  
Masato Ohnishi ◽  
Yang Meng ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Carbon Nanotubes ◽  
Spatial Distribution ◽  
High Performance ◽  
Thermal Deformation ◽  
State Energy ◽  
Lattice Mismatch ◽  
Electronic Devices ◽  
Radial Strain ◽  
First Principles Calculation ◽  
State Densities

In any electronic devices and sensors, unexpected changes in their function occur due to internal strain caused by contact of different materials which leads to thermal deformation or lattice mismatch. Thus, understanding of the effect of strain on electronic properties of carbon nanotubes (CNTs) is indispensable for assuring the reliability of CNTs-based electronic devices and for developing new electronic devices and sensors. In this study, the change in spatial distribution of state densities of zigzag CNTs under radial strain is analyzed by using first-principles calculation. The analysis shows that when a radial strain is applied to a CNT, its state densities are localized at high curvature regions. Such localization of state densities decrease their energies, and then decrease the band gap. In addition, since the behavior of the state energy under the radial strain is dominated by its spatial distribution, the strain sensitivity of CNTs depends on their chirality. The founding gives a guideline on how to fabricate high-performance novel CNTs devices, sensors, for example, biaxial strain sensor.

scholarly journals Sources of ice block falls at the Martian north polar scarps: detection from multi-temporal HiRISE image sets

2021 ◽  
Author(s):  
Shu Su ◽  
Lida Fanara ◽  
Xin Zhang ◽  
Klaus Gwinner ◽  
Ernst Hauber ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Digital Terrain Model ◽  
Time Of Day ◽  
Mass Wasting ◽  
Geophysical Research ◽  
Temporal And Spatial Distribution ◽  
Detection Techniques ◽  
Multi Temporal ◽  
Imaging Science ◽  
North Polar

<p>The North Polar Layered Deposits (NPLD), which consist of dusty water ice layers, have recorded the climatic variations of Mars. We use High Resolution Imaging Science Experiment (HiRISE) data (ground pixel size of up to ~0.25m/pixel) to study the morphology and current erosional processes at the NPLD scarps. Fanara et al. (1,2) have performed automated detection of the fallen ice blocks at the foot of scarps. Our aim is to search for their possible source areas.</p><p>We apply change detection techniques to multi-temporal images. The images are ortho-rectified using HiRISE Digital Terrain Model (DTM) and then co-registered to ensure subpixel alignment accuracy. Due to the low-sun conditions in Martian polar areas, the surface morphology can be revealed from cast shadows. In addition, HiRISE operates on a nearly sun-synchronous orbit, which means the images are taken at the same local time of day, providing good conditions for automatically detecting changes in shadow patterns of the ice-fragments.</p><p>The areas with changed shadows illustrate the spatial distribution of mass wasting activities. Our results show that most of the detached ice-fragments originate from the lower parts of the scarp, which are heavily affected by fracturing. Based on the detected changes, we will further investigate the characteristics of mass wasting and estimate the volume of the detached ice-fragments. The temporal and spatial distribution of detached ice fragments at different NPLD scarps can provide insights into the ice behavior and thus support modelling studies of viscous flow velocities (3), thermoelastic stresses (4) and climate variations of Mars. Ultimately, we intend to explore the evolution of the NPLD scarps by correlating long-term mass wasting characteristics with seasonal and morphological parameters.</p><p> </p><p>References</p><p>[1] Fanara et al.,2020. Planetary and Space Science. 180, p.104733.</p><p>[2] Fanara et al.,2020. Icarus. 342, p.113434.</p><p>[3] Sori et al., 2016. Geophysical Research Letters, 43(2), pp.541-549.</p><p>[4] Byrne et al., 2017. EPSC, Vol. 11.</p>

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