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32 results for “MARSIS”
MARSIS Transient Layer Detections during Comet Siding Spring Event 2014
<p><strong>This data is used in the publication, "Prolonged Lifetime of the Transient Ionized Layer in the Martian Atmosphere Caused by Comet Siding Spring" by Luppen et al. 2020.</strong></p> <p>MARSIS_transient_layer_detections.csv: The data contained in this file are measurements from the Mars Express spacecraft's MARSIS instrument, collected during the Comet Siding Spring flyby event in 2014. The comet is known to have deposited a large amount of material into Mars' ionosphere, producing a transient layer of plasma that was noticed by multiple spacecraft instruments immediately following the comet's closest approach to the planet. The layer was originally thought to have had a lifetime of 1-2 days. Follow-up analysis, represented in this data file, indicate that this layer could have lasted at least 7 days and as many as 32 days after closest approach, much longer than previously reported. Our results help to constrain models of metal ion chemistry in the Martian upper atmosphere.</p> <p>MARSIS_regular_ionospheric_measurements.csv: The data contained in this file are measurements of the regular ionosphere during the comet Siding Spring event. These data are plotted in Figures 3 and 4 of the manuscript.</p> <p>MAVEN_normalized_euv_irradiance.csv: The data contained in this file are measurements collected from the Extreme UltraViolet (EUV) monitor that is part of the Langmuir Probe and Waves (LPW) instrument on the MAVEN spacecraft collected during the comet Siding Spring event. These data are plotted in Figure 5 of the manuscript.</p> <p>FISM_normalized_euv_irradiance.csv: The data contained in this file are measurements collected from the Flare Irradiance Spectral Model (FISM) collected during the comet Siding Spring event. These data are plotted in Figure 5 of the manuscript.</p> <p>MARSIS_averaged_data_figure4.csv: The data contained in this file are derived products from the MARSIS_regular_ionospheric_measurements.csv data. A running mean was calculated with 2 degree SZA bins, the SZA centers of those bins were identified, and a standard deviation was calculated for each bin. These data are plotted in Figure 4 of the manuscript. Note that we make use of a shaded region signifying a 3 sigma standard deviation.</p>
MARSIS surface clutter simulations over Lucus Planun, Mars
<p>Mars Express MARSIS radargram simulations over Lucus Planum (Mars)</p> <p>This archive contains simulations of radar surface scattering for the MARSIS low-frequency radar over the area of Lucus Planum.</p> <p>Ground Penetrating Radar (GPR) is a well-established geophysical technique employed for more than five decades to investigate the terrestrial subsurface. It is based on the transmission of radar pulses at frequencies in the MF, HF and VHF portions of the electromagnetic spectrum into the surface, to detect reflected signals from subsurface structures (see e.g. Bogorodsky et al. 1985). Orbiting GPR have been successfully employed in planetary exploration (Phillips et al. 1973, Picardi et al. 2004, Seu et al. 2007, Ono et al. 2009), and are often called subsurface radar sounders. By detecting dielectric discontinuities associated with compositional and/or structural discontinuities, radar sounders are the only remote sensing instruments allowing the study of the subsurface of a planet from orbit.</p> <p>MARSIS is a synthetic-aperture, orbital sounding radar carried by the European Space Agency spacecraft Mars Express (Picardi et al. 2005). MARSIS is optimized for deep penetration, having detected echoes down to a depth of 3.7 km over the South Polar Layered Deposits (Plaut el al. 2007). MARSIS transmits through a dipole, which has negligible directivity, with the consequence that the radar pulse illuminates the entire surface beneath the spacecraft and not only the near-nadir portion from which subsurface echoes are expected. The electromagnetic wave can then be scattered by any roughness of the surface.</p> <p>If the surface of the body being sounded is not smooth at the wavelength scale, i.e. if the r.m.s. of topographic heights is greater than a fraction of the wavelength, then part of the incident radiation will be scattered in directions different from the specular one. This means that areas of the surface that are not directly beneath the radar can scatter part of the incident radiation back towards it, and thus produce surface echoes that will reach the radar after the echo coming from nadir, which can mask, or be mistaken for, subsurface echoes. This surface backscattering from off-nadir directions is called "clutter".</p> <p>To validate the detection of subsurface interfaces, numerical electromagnetic models of surface scattering, such as those by Nouvel et al. (2004), Russo et al. (2008) or Spagnuolo et al. (2011), have been used to produce simulations of surface echoes, which are then compared to real echoes detected by the radar. A code for the simulation of radar wave surface scattering has been developed, based on the work of Nouvel et al. (2004), using the MOLA topographic dataset (Smith et al. 2001) to represent the Martian surface as a collection of flat plates called facets. The radar echo is computed as the coherent sum of reflections from all facets illuminated by the radar. The computational burden of every simulation is very high but, thanks to a collaboration with CINECA, the code has been parallelized and ported for use in a Blue Gene/Q system. The code has been tested and its performance evaluated on the Fermi machine at CINECA.</p> <p>The data included in this archive simulate MARSIS observations over the area of Lucus Planum, in the equatorial region of Mars, and have been used in the paper "Radar sounding of Lucus Planum, Mars, by MARSIS" by Orosei, Rossi, Cantini, Caprarelli, Carter, Papiano, Cartacci, Cicchetti and Noschese, accepted for pubblication on Journal of Geophysical Research - Planets. A direct comparison of simulations with actual observations allows to unambiguously identify subsurface echoes in MARSIS radargrams. Echoes reaching the radar after nadir surface echoes will be identified as coming from the subsurface if they are not present in simulations. Conversely, any secondary echo that is present in both real and simulated data must be interpreted as coming from the surface.</p> <p>The numerical code for the simulation of surface scattering was developed at the Consorzio Interuniversitario per il Calcolo Automatico dell'Italia Nord-Orientale (CINECA) in Bologna, Italy. Simulations were produced thanks to the Partnership for Advanced Computing in Europe (PRACE), awarding us access to the SuperMUC computer at the Leibniz-Rechenzentrum, Garching, Germany through project 2013091832. Test simulations were run Jacobs University CLAMV HPC cluster, and we are grateful to Achim Gelessus for his support.</p> <p><br> REFERENCES</p> <p>Bogorodsky, V., Bentley, C., Gudmandsen, P. 1985. Radioglaciology. Reidel, Dordrecht. ISBN 90-277-1893-8</p> <p>Nouvel, J.-F., Herique, A., Kofman, W., Safaeinili, A. 2004. Radar signal simulation: Surface modeling with the Facet Method. Radio Science 39, 1013.</p> <p>Ono, T., Kumamoto, A., Nakagawa, H., Yamaguchi, Y., Oshigami, S., Yamaji, A., Kobayashi, T., Kasahara, Y., Oya, H. 2009. Lunar Radar Sounder Observations of Subsurface Layers Under the Nearside Maria of the Moon. Science 323, 909.</p> <p>Phillips, R.J., and 14 colleagues 1973. Apollo Lunar Sounder Experiment. NASA Spec. Pub. 330, (22) 1-26.</p> <p>Picardi, G., and 12 colleagues 2004. MARSIS: Mars Advanced Radar for Subsurface and Ionosphere Sounding, In: Mars Express: the scientific payload. ESA Publications Division, 51-69.</p> <p>Picardi, G., and 33 colleagues 2005. Radar Soundings of the Subsurface of Mars. Science 310, 1925-1928.</p> <p>Plaut, J. J., and 23 colleagues 2007. Subsurface Radar Sounding of the South Polar Layered Deposits of Mars. Science 316, 92.</p> <p>Russo, F., Cutigni, M., Orosei, R., Taddei, C., Seu, R., Biccari, D., Giacomoni, E., Fuga, O., Flamini, E. 2008. An incoherent simulator for the SHARAD experiment. Radar Conference, 2008. RADAR '08. IEEE 26-30 May 2008, 1.</p> <p>Seu, R., and 11 colleagues 2007. SHARAD sounding radar on the Mars Reconnaissance Orbiter. Journal of Geophysical Research (Planets) 112, 5.</p> <p>Smith, D. E., and 23 colleagues 2001. Mars Orbiter Laser Altimeter (MOLA): Experiment summary after the first year of global mapping of Mars. J. Geophys. Res. 106, 23,689-23,722.</p> <p>Spagnuolo, M. G., Grings, F., Perna, P., Franco, M., Karszenbaum, H., Ramos, V. A. 2011. Multilayer simulations for accurate geological interpretations of SHARAD radargrams. Planetary and Space Science 59, 1222.</p>
Datatset associated to Journal of Marine Systems submission : Ms. No. MARSYS-D-21-00246R1
<p>Individual growth increment measurements (µm) of the 21 live collected <em>A. islandica</em> used in the publication entitled : "The 18.6-year lunar nodal cycle may affect ecosystems on the Northwest Atlantic continental shelves". All information regarding data acquisition are presented in the section "2. Construction of <em>Arctica islandica </em>master chronology" of the article submitted to Journal of Marine Systems.</p> <p>Data are presented as a "Tucson File" which is a standard format for tree-ring dataset (see : <a href="http://www.cybis.se/wiki/index.php?title=Tucson_format">http://www.cybis.se/wiki/index.php?title=Tucson_format</a> for a precise description).</p> <p> </p>
MARSIS Electron Cyclotron Echo Data Set
<p>This data set contains the electron cyclotron period, T_ce, manually extracted from electron cyclotron echoes recorded in MARSIS ionograms. The local magnetic field magnitude can be derived as B = 2 pi m_e / (e * T_ce).</p>
Data files used in the paper "First Radar Evidence of Large-Scale Englacial Folding in the South Polar Layered Deposits (Ultimi Scopuli, Mars) and Possible Ice Sheet Flow Unveiled by MARSIS" By Guallini et al.
<p>This archive contains radargrams, geometric information and visualizations of a subset of MARSIS radar observations over Planum Australe, Mars. This archive contains everything needed to reproduce the results presented in the paper "Large-scale folds detected by MARSIS in the Southern ice sheet of Ultimi Scopuli (Mars)" by Guallini et al.</p> <p>Three types of MARSIS data files are contained in this archive:</p> <p>* orbit_XXXXX_frequency_Y_MHz_radargram.csv, where XXXXX is the orbit number, and Y the frequency at which the radar was operating, in MHz. The file contains an ASCII table of real numbers separated by commas. The table has as many columns as the number of radar echoes acquired during the orbit (usually 3200), and 980 lines, one for each echo sample. Values are samples of the uncalibrated echo voltage, without phase information (i.e. positive real numbers instead of complex echo samples). Echo samples are acquired every 0.3571 microseconds (2.8 MHz sampling rate). The first sample of an echo is located at a round-trip time corresponding to an altitude of 25 km above the Martian IAU ellipsoid.</p> <p>* orbit_XXXXX_frequency_Y_MHz_geometry.csv, where XXXXX is the orbit number, and Y the frequency at which the radar was operating, in MHz. The file contains an ASCII table of real numbers separated by commas. The table has as many rows as the number of radar echoes acquired during the orbit (usually 3200), and contains the following auxiliary parameters:</p> <p> - EPHEMERIS TIME - Number of seconds elapsed since Jan 1, 2000, 12:00 UTC corresponding to the time at which data collection for the current echo started.</p> <p> - MARS SOLAR LONGITUDE - Angle between the Mars-Sun line at the time corresponding to EPHEMERIS TIME and the Mars-Sun line at the vernal equinox, in degrees.</p> <p> - MARS SUN DISTANCE - Distance from the centre of Mars to centre of the Sun at the time corresponding to EPHEMERIS TIME, in Km.</p> <p> - SPACECRAFT ALTITUDE - Distance from the Mars Express spacecraft to the reference surface of the target body measured normal to the surface at the time corresponding to EPHEMERIS TIME, expressed in Km.</p> <p> - SUB-SPACECRAFT LONGITUDE - East longitude of the point on the target body that lies closest to the Mars Express spacecraft at the time corresponding to EPHEMERIS TIME, expressed in degrees and in the [ 0 -360 ] range.</p> <p> - SUB-SPACECRAFT LATITUDE - Planetocentric latitude of the point on the target body that lies directly beneath the Mars Express spacecraft at the time corresponding to EPHEMERIS TIME, expressed in degrees.</p> <p> - RADIAL VELOCITY - Radial component of the Mars Express spacecraft velocity vector in the reference frame of the target body at the time corresponding to EPHEMERIS TIME, expressed in Km/s.</p> <p> - TANGENTIAL VELOCITY - Tangential component of the Mars Express spacecraft velocity vector in the reference frame of the target body at the time corresponding to EPHEMERIS TIME, expressed in Km/s.</p> <p> - LOCAL TRUE SOLAR TIME - Angle between the extension of the vector from the Sun to Mars and the projection on Mars' ecliptic plane of a vector from the center of the target body and the point on the target body surface that lies directly beneath the Mars Express spacecraft at the time corresponding to EPHEMERIS TIME, expressed on a 24-hour clock with decimal fractions of the hour.</p> <p>* orbit_XXXXX_frequency_Y_MHz.png, where XXXXX is the orbit number, and Y the frequency at which the radar was operating, in MHz. The file is a visualization of the corresponding radargram, of the spacecraft ground track during the observation, and of surface and subsurface echo power.</p>
Data files used in the paper " Multiple subglacial water bodies below the south pole of Mars unveiled by new MARSIS data "
<pre>Each file corresponds to a MARSIS radar acquisition on the Ultima Scopuli on Mars. The Data are in ASCII format and they organized as a follow: first row: operating frequency in MHz second row: longitude in degree third row: latitude in degree forth row: spacecraft height from fifth row to the end row: amplitude radar signal The name of the file corresponds to name of the MARSIS orbit</pre>
MARS EXPRESS MARS MARSIS EXPERIMENT DATA RECORD EXT 4 V1.0
This dataset contains the scientific telemetry produced by the MARSIS instrument after editing for duplicated and corrupted packets, together with geometric information computed on ground to locate observations in space and time. Both subsurface and ionosphere sounding data are included in the dataset.
MEX: MARSIS ELECTRON PLASMA DENSITY AND MAGNETIC FIELD DATA
This data set tabulates local electron densities and local magnetic field strengths magnetic field strengths obtained from Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) Active Ionospheric Sounding (AIS) mode ionograms. The electron density is obtained by measuring the increment in frequency between the plasma frequency harmonics, visible as bright vertical lines at low frequency and delay time in many MARSIS ionograms. Similarly, the local magnetic field strength is found by measuring the difference in delay time between electron cyclotron echoes, visible as bright horizontal lines at low frequency on many ionograms. Both the measured quantity and the derived result are included in the archive product. We also include a data quality flag giving the impression of the archivist as to how reliable each result is. This archive product includes only data from the nominal mission, which starts about orbit 1850 and ends on orbit 2539.
MARS EXPRESS MARSIS RDR ACTIVE IONOSPHERE SOUNDING EXT6 V1.0
The Mars Express MARSIS Active Ionospheric Sounder (AIS) full resolution data set includes all spectral information calibrated in units of spectral density for the Mars Express sixth extended mission. The data set consists of a transmit frequency followed by a time series of spectral density measurements of the received power. Browse products contain a spectrogram overview plot and individual ionograms for each sounding activity.
MEX: MARSIS ELECTRON PLASMA DENSITY AND MAGNETIC FIELD DATA
This data set tabulates local electron densities and local magnetic field strengths magnetic field strengths obtained from Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) Active Ionospheric Sounding (AIS) mode ionograms. The electron density is obtained by measuring the increment in frequency between the plasma frequency harmonics, visible as bright vertical lines at low frequency and delay time in many MARSIS ionograms. Similarly, the local magnetic field strength is found by measuring the difference in delay time between electron cyclotron echoes, visible as bright horizontal lines at low frequency on many ionograms. Both the measured quantity and the derived result are included in the archive product. We also include a data quality flag giving the impression of the archivist as to how reliable each result is. This archive product includes only data from the nominal mission, which starts about orbit 1850 and ends on orbit 2539.
MARS EXPRESS MARSIS REDUCED DATA SUBSURFACE EXT 1 V1.0
This dataset contains subsurface sounding data from the MARS EXPRESS MARS MARSIS EXPERIMENT DATA RECORD V2.0 Data Set that have been uncompressed, corrected for Automated Gain Control, aligned to a reference altitude and, except for data acquired using the SS2 mode, range processed after correcting for the distortion of the transmitted signal caused by the ionosphere.
MARS EXPRESS MARSIS REDUCED DATA SUBSURFACE EXT 6 V1.0
This dataset contains subsurface sounding data from the MARS EXPRESS MARS MARSIS EXPERIMENT DATA RECORD EXTENSION 6 V1.0 Data Set that have been uncompressed, corrected for Automated Gain Control, aligned to a reference altitude and, except for data acquired using the SS2 mode, range processed after correcting for the distortion of the transmitted signal caused by the ionosphere.
MARS EXPRESS MARSIS DERIVED SUBSURFACE TEC DATA EXT 1 V1.0
This dataset contains the Level 5 data that have been processed to produce Total Electron Count data from the MARSIS subsurface sounder on Mars Express. Details of the calibration and processing reports are found in the documntation associated with this data set.
MARS EXPRESS MARS MARSIS DERIVED SUBSURFACE TEC DATA V1.0
This dataset contains the Level 5 data that have been processed to produce Total Electron Count data from the MARSIS subsurface sounder on Mars Express. Details of the calibration and processing reports are found in the documntation associated with this data set.
MARS EXPRESS MARSIS REDUCED DATA SUBSURFACE EXT 3 V1.0
This dataset contains subsurface sounding data from the MARS EXPRESS MARS MARSIS EXPERIMENT DATA RECORD V2.0 Data Set that have been uncompressed, corrected for Automated Gain Control, aligned to a reference altitude and, except for data acquired using the SS2 mode, range processed after correcting for the distortion of the transmitted signal caused by the ionosphere.
MARS EXPRESS MARS MARSIS EXPERIMENT DATA RECORD EXT 3 V1.0
This dataset contains the scientific telemetry produced by the MARSIS instrument after editing for duplicated and corrupted packets, together with geometric information computed on ground to locate observations in space and time. Both subsurface and ionosphere sounding data are included in the dataset.
MARS EXPRESS MARS MARSIS EXPERIMENT DATA RECORD EXT 1 V2.0
This dataset contains the scientific telemetry produced by the MARSIS instrument after editing for duplicated and corrupted packets, together with geometric information computed on ground to locate observations in space and time. Both subsurface and ionosphere sounding data are included in the dataset.
MARS EXPRESS MARS MARSIS EXPERIMENT DATA RECORD EXT 5 V1.0
This dataset contains the scientific telemetry produced by the MARSIS instrument after editing for duplicated and corrupted packets, together with geometric information computed on ground to locate observations in space and time. Both subsurface and ionosphere sounding data are included in the dataset.
MARS EXPRESS MARSIS RDR ACTIVE IONOSPHERE SOUNDING EXT5 V1.0
The Mars Express MARSIS Active Ionospheric Sounder (AIS) full resolution data set includes all spectral information calibrated in units of spectral density for the Mars Express fifth extended mission. The data set consists of a transmit frequency followed by a time series of spectral density measurements of the received power. Browse products contain a spectrogram overview plot and individual ionograms for each sounding activity.
MARS EXPRESS MARSIS RDR ACTIVE IONOSPHERE SOUNDING EXT3 V1.0
The Mars Express MARSIS Active Ionospheric Sounder (AIS) full resolution data set includes all spectral information calibrated in units of spectral density for the Mars Express third extended mission, EXT3. The data set consists of a transmit frequency followed by a time series of spectral density measurements of the received power. Browse products contain a spectrogram overview plot and individual ionograms for each sounding activity.
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