Examinando por Autor "Lemmon, M. T."

Mostrando 1 - 5 de 5

Acceso Abierto
A Study of Daytime Convective Vortices and Turbulence in the Martian Planetary Boundary Layer Based on Half-a-Year of InSight Atmospheric Measurements and Large-Eddy Simulations
(American Geophysical Union: Advancing Earth and Space Science, 2021-01-12) Spiga, A.; Murdoch, N.; Lorenz, R.; Forget, F.; Newman, C. E.; Rodríguez, Sébastien; Pla García, J.; Viúdez Moreiras, Daniel; Banfield, D.; Perrin, C.; Mueller, N. T.; Lemmon, M. T.; Millour, E.; Banerdt, W. B.; Agencia Estatal de Investigación (AEI); Spiga, A. [0000-0002-6776-6268]; Murdoch, N. [0000-0002-9701-4075]; Lorenz, R. [0000-0001-8528-4644]; Forget, F. [0000-0002-3262-4366]; Newman, C. [0000-0001-9990-8817]; Rodríguez, S. [0000-0003-1219-0641]; Pla García, J. [0000-0002-8047-3937]; Viúdez Moreiras, D. [0000-0001-8442-3788]; Perrin, C. [0000-0002-7200-5682]; Mueller, N. T. [0000-0001-9229-8921]; Lemmon, M. [0000-0002-4504-5136]; Millour, E. [0000-0003-4808-9203]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Studying the atmospheric planetary boundary layer (PBL) is crucial to understand the climate of a planet. The meteorological measurements by the instruments onboard InSight at a latitude of 4.5°N make a unique rich data set to study the active turbulent dynamics of the daytime PBL on Mars. Here we use the high-sensitivity continuous pressure, wind, and temperature measurements in the first 400 sols of InSight operations (from northern late winter to midsummer) to analyze wind gusts, convective cells, and vortices in Mars’ daytime PBL. We compare InSight measurements to turbulence-resolving large-eddy simulations (LES). The daytime PBL turbulence at the InSight landing site is very active, with clearly identified signatures of convective cells and a vast population of 6,000 recorded vortex encounters, adequately represented by a power law with a 3.4 exponent. While the daily variability of vortex encounters at InSight can be explained by the statistical nature of turbulence, the seasonal variability is positively correlated with ambient wind speed, which is supported by LES. However, wind gustiness is positively correlated to surface temperature rather than ambient wind speed and sensible heat flux, confirming the radiative control of the daytime Martian PBL; and fewer convective vortices are forming in LES when the background wind is doubled. Thus, the long-term seasonal variability of vortex encounters at the InSight landing site is mainly controlled by the advection of convective vortices by ambient wind speed. Typical tracks followed by vortices forming in the LES show a similar distribution in direction and length as orbital imagery.
Acceso Abierto
Effects of a Large Dust Storm in the Near‐Surface Atmosphere as Measured by InSight in Elysium Planitia, Mars. Comparison With Contemporaneous Measurements by Mars Science Laboratory
(American Geophysical Union: Advancing Earth and Space Science, 2020-08-11) Viúdez Moreiras, Daniel; Newman, C. E.; Forget, F.; Lemmon, M. T.; Banfield, D.; Spiga, A.; Lepinette, A.; Rodríguez Manfredi, J. A.; Gómez Elvira, J.; Pla García, J.; Muller, N.; Grott, M.; TWINS/InSight team; Agencia Estatal de Investigación (AEI); Centre National D'Etudes Spatiales (CNES); Spiga, A. [0000-0002-6776-6268]; Lemmon, M. [0000-0002-4504-5136]; Newman, C. [0000-0001-9990-8817]; Pla garcía, J. [0000-0002-8047-3937]; Mueller, N. [0000-0001-9229-8921]
NASA's InSight landed in Elysium Planitia (~4.5°N,136°E) at Ls ~ 296° (November 2018), right after the decay of the 2018 Global Dust Storm (GDS) and before the onset of the 2019 Large Dust Storm (LDS) at Ls ~ 320° (January 2019). InSight's cameras observed a rise in the atmospheric opacities during the storm from ~0.7 to ~1.9, similarly to contemporaneous measurements by Curiosity in Gale crater. Pressure tides were strongly affected at the locations of InSight and Curiosity. In particular, the diurnal pressure mode experienced an abrupt increase during the onset of the LDS, similar to that measured by Curiosity, most likely due to longitudinally asymmetric dust loading. Later, the dust was redistributed around the planet and the semidiurnal mode evolved according to dust opacity in both missions. Before and after the onset of the storm, the observed wind patterns resulted from the interaction between regional and local slope flows induced by topography, which all produced a diurnal perturbation superimposed on a mean flow, dominated by the Hadley cell but with modifications due to channeling effects from the regional topography. However, the onset of the LDS modified this to a scenario consistent with enhanced tidal flows. The local air temperatures are strongly perturbed by the lander's thermal effects, and their retrieval significantly depends on wind patterns, which changed during the course of the dust storm. Observations suggest a decrease in convective vortices during the dust storm; however, vortex activity remained strong during the storm's onset due to the increase in wind speeds.
Acceso Abierto
In Situ UV Measurements by MSL/REMS: Dust Deposition and Angular Response Corrections
(Springer Link, 2020-07-21) Retortillo, A. V.; Martínez, G. M.; Rennó, N. O.; Lemmon, M. T.; De la Torre Juárez, M.; Gómez Elvira, J.; NASA Jet Propulsion Laboratory (JPL); Retortillo, A. V. [0000-0002-4553-7624]; Gómez Elvira, J. [0000-0002-9068-9846]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Measurements by the REMS/UV sensor onboard the MSL Curiosity rover constitute the first in situ dataset of UV radiation flux at the surface of Mars. Due to its position on the Curiosity deck, the UV sensor has been directly exposed to dust deposition. Inaccuracies in the original angular response calibration functions have led to discrepancies between measured and physically-expected UV fluxes when the solar zenith angle (theta) relative to the rover frame is between 20 degrees and 55 degrees. Here we present a methodology to correct UV fluxes when theta < 55 degrees for both effects, and show results of the corrected data set for the first 2003 sols (similar to 3 Martian Years, MY) of the MSL mission, from L-s similar to 151 degrees in MY 31 to L-s similar to 149 degrees in MY 34. Close to noon, when. values are typically < 30 degrees, relative differences between corrected and original UV fluxes are similar to 35 - 40% on average. Outside hours close to noon, when theta is typically > 30 degrees, relative differences are greater than 100%. Measurements acquired when 20 degrees < theta < 55 degrees represent similar to 45% of the whole dataset with theta < 90 degrees. UV fluxes generated in this study are available in the NASA Planetary Data System (https://atmos.nmsu.edu/PDS/data/mslrem_1001/DATA_UV_CORRECTED/), and are important to study the effect of UV radiation on the variability of atmospheric constituents, to recreate accurate UV doses for biological laboratory experiments, to perform combined analyses of satellite and ground-based measurements, and to allow comparisons of the UV radiation environment at different locations with the upcoming ExoMars 2020 and Mars 2020 missions.
Restringido
Initial results from the InSight mission on Mars
(Nature Research Journals, 2020-02-24) Banerdt, W. B.; Smrekar, S.; Banfield, D.; Giardini, D.; Golombek, M.; Johnson, C. L.; Lognonné, P.; Spiga, A.; Spohn, T.; Perrin, C.; Stähler, S.; Antonangeli, D.; Asmar, S.; Beghein, C.; Bowles, N.; Bozdag, E.; Chi, P.; Christensesn, U.; Clinton, J.; Collins, G. S.; Daubar, I.; Dehant, V.; Drilleau, M.; Fillingim, M.; Folkner, W.; García, R. F.; Garvin, J. B.; Grant, J.; Grott, M.; Grygorczuk, J.; Hudson, T.; Irving, J. C. E.; Kargl, G.; Kawamura, T.; Kedar, S.; King, S.; Knapmeyer Endrun, B.; Knapmeyer, M.; Lemmon, M. T.; Lorenz, R.; Maki, Justin N.; Margerin, L.; McLennan, S. M.; Michaut, C.; Mimoun, D.; Mittelholz, A.; Mocquet, A.; Morgan, P.; Mueller, N. T.; Murdoch, N.; Nagihara, S.; Newman, C. E.; Nimmo, F.; Panning, M.; Thomas Pike, W.; Plesa, A. C.; Rodríguez, Sébastien; Rodríguez Manfredi, J. A.; Russell, C. T.; Chmerr, N.; Siegler, M.; Stanley, S.; Stutzmann, E.; Teanby, N.; Tromp, J.; Van Driel, M.; Warner, N.; Weber, R.; Wieczorek, Mark A.; Agence Nationale de la Recherche (ANR); Swiss National Science Foundation (SNSF); Tromp, J. [0000-0002-2742-8299]; Rodríguez, S. [0000-0003-1219-0641]; Lognonné, P. [0000-0002-1014-920X]; Perrin, C. [0000-0002-7200-5682]; Murdoch, N. [0000-0002-9701-4075]; Knapmeyer, M. [0000-0003-0319-2514]; Rodríguez Manfredi, J. A. [0000-0003-0461-9815]; Spiga, A. [0000-0002-6776-6268]; Panning, M. P. [0000-0002-2041-3190]; García, R. [0000-0003-1460-6663]; Johnson, C. [0000-0001-6084-0149]; Stutzmann, E. [0000-0002-4348-7475]; Knapmeyer-Endrun, B. [0000-0003-3309-6785]; Schmerr, N. [0000-0002-3256-1262]; Irving, J. C. E. [0000-0002-0866-8246]; Morgan, P. [0000-0001-8714-4178]; Mueller, N. [0000-0001-9229-8921]; Pike, W. [0000-0002-7660-6231]; Kawamura, T. [0000-0001-5246-5561]; Clinton, J. [0000-0001-8626-2703]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
NASA’s InSight (Interior exploration using Seismic Investigations, Geodesy and Heat Transport) mission landed in Elysium Planitia on Mars on 26 November 2018. It aims to determine the interior structure, composition and thermal state of Mars, as well as constrain present-day seismicity and impact cratering rates. Such information is key to understanding the differentiation and subsequent thermal evolution of Mars, and thus the forces that shape the planet’s surface geology and volatile processes. Here we report an overview of the first ten months of geophysical observations by InSight. As of 30 September 2019, 174 seismic events have been recorded by the lander’s seismometer, including over 20 events of moment magnitude Mw = 3–4. The detections thus far are consistent with tectonic origins, with no impact-induced seismicity yet observed, and indicate a seismically active planet. An assessment of these detections suggests that the frequency of global seismic events below approximately Mw = 3 is similar to that of terrestrial intraplate seismic activity, but there are fewer larger quakes; no quakes exceeding Mw = 4 have been observed. The lander’s other instruments—two cameras, atmospheric pressure, temperature and wind sensors, a magnetometer and a radiometer—have yielded much more than the intended supporting data for seismometer noise characterization: magnetic field measurements indicate a local magnetic field that is ten-times stronger than orbital estimates and meteorological measurements reveal a more dynamic atmosphere than expected, hosting baroclinic and gravity waves and convective vortices. With the mission due to last for an entire Martian year or longer, these results will be built on by further measurements by the InSight lander.
Restringido
The atmosphere of Mars as observed by InSight.
(Nature Research Journals, 2020-02-24) Banfield, D.; Spiga, A.; Newman, C. E.; Forget, F.; Lemmon, M. T.; Lorenz, R.; Murdoch, N.; Viúdez Moreiras, Daniel; Pla García, J.; García, R. F.; Lognonné, P.; Karatekin, Özgür; Perrin, C.; Martire, L.; Teanby, N.; Van Hove, B.; Maki, Justin N.; Kenda, B.; Mueller, N. T.; Rodriguez, Sébastien; Kawamura, T.; McClean, J. B.; Stott, A. E.; Charalambous, C.; Millour, E.; Johnson, C. L.; Mittelholz, A.; Määttänen, A.; Lewis, S. R.; Clinton, J.; Stähler, S. C.; Ceylan, S.; Giardini, D.; Warren, T.; Pike, W. T.; Daubar, I.; Golombek, M.; Rolland, L.; Widmer Schnidrig, R.; Mimoun, D.; Beucler, E.; Jacob, A.; Lucas, A.; Baker, M.; Ansan, V.; Hurst, K.; Mora Sotomayor, L.; Navarro, Sara; Torres, J.; Lepinette, A.; Molina, A.; Marín Jiménez, M.; Gómez Elvira, J.; Peinado, V.; Rodríguez Manfredi, J. A.; Carchic, B. T.; Sackett, S.; Russell, C. T.; Spohn, T.; Smrekar, S. E.; Banerdt, W. B.; Agence Nationale de la Recherche (ANR); Määttänen, A. [0000-0002-7326-8492]; Martire, L. [0000-0002-9402-6150]; Rodríguez Manfredi, J. A. [0000-0003-0461-9815]; Lognonné, P. [0000-0002-1014-920X]; Rodríguez, S. [0000-0003-1219-0641]; Spiga, A. [0000-0002-6776-6268]; Perrin, C. [0000-0002-7200-5682]; Molina, A. [0000-0002-5038-2022]; Rodríguez Manfredi, J. A. [0000-0003-0461-9815]; García, R. [0000-0003-1460-6663]; Murdoch, N. [0000-0002-9701-4075]; Lorenz, R. [0000-0001-8528-4644]; Mittelholz, A. [0000-0002-5603-7334]; Kawamura, T. [0000-0001-5246-5561]; Widmer Schnidrig, R. [0000-0001-9698-2739]; McClean, J. [0000-0002-7863-0120]; Mueller, N. [0000-0001-9229-8921]; Lewis, S. [0000-0001-7237-6494]; Teanby, N. [0000-0003-3108-5775]; Warren, T. [0000-0003-3877-0046]; Milliour, E. [0000-0003-4808-9203]; Lemmon, M. [0000-0002-4504-5136]; Clinton, J. [0000-0001-8626-2703]; Ceylan, S. [0000-0002-6552-6850]; Banfield, D. [0000-0003-2664-0164]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
The atmosphere of Mars is thin, although rich in dust aerosols, and covers a dry surface. As such, Mars provides an opportunity to expand our knowledge of atmospheres beyond that attainable from the atmosphere of the Earth. The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) lander is measuring Mars’s atmosphere with unprecedented continuity, accuracy and sampling frequency. Here we show that InSight unveils new atmospheric phenomena at Mars, especially in the higher-frequency range, and extends our understanding of Mars’s meteorology at all scales. InSight is uniquely sensitive to large-scale and regional weather and obtained detailed in situ coverage of a regional dust storm on Mars. Images have enabled high-altitude wind speeds to be measured and revealed airglow—faint emissions produced by photochemical reactions—in the middle atmosphere. InSight observations show a paradox of aeolian science on Mars: despite having the largest recorded Martian vortex activity and dust-devil tracks close to the lander, no visible dust devils have been seen. Meteorological measurements have produced a catalogue of atmospheric gravity waves, which included bores (soliton-like waves). From these measurements, we have discovered Martian infrasound and unexpected similarities between atmospheric turbulence on Earth and Mars. We suggest that the observations of Mars’s atmosphere by InSight will be key for prediction capabilities and future exploration.