Examinando por Autor "Lorenz, Ralph"

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Acceso Abierto
Convective Vortices and Dust Devils Detected and Characterized by Mars 2020
(AGU Advancing Earth and Space Science, 2023-02-10) Hueso, R.; Newman, C. E.; Del Río Gaztelurrutia, T.; Munguira, A.; Sánchez Lavega, Agustín; Toledo, D.; Apéstigue, Víctor; Arruego, Ignacio; Vicente Retortillo, Álvaro; Martínez, Germán M.; Lemmon, M. T.; Lorenz, Ralph; Richardson, M. I.; Viúdez Moreiras, Daniel; De la Torre Juárez, M.; Rodríguez Manfredi, J. A.; Tamppari, L. K.; Murdoch, N.; Navarro López, Sara; Gómez Elvira, J.; Baker, M.; Pla García, J.; Harri, Ari-Matti; Hieta, M.; Genzer, María; Polkko, J.; Jaakonaho, I.; Makinen, Terhi; Stott, Alexander; Mimoun, D.; Chide, B.; Sebastián Martínez, Eduardo; Banfield, D.; Lepinette Malvitte, A.; Gobierno Vasco; Ministerio de Ciencia e Innovación (MICINN); Agencia Estatal de Investigación (AEI); Ministerio de Economía y Competitividad (MINECO); Los Alamos National Laboratory (LANL); Arizona State University (ASU); Universities Space Research Association (USRA); NASA Jet Propulsion Laboratory (JPL); Comunidad de Madrid; Academy of Finland (AKA); Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
We characterize vortex and dust devils (DDs) at Jezero from pressure and winds obtained with the Mars Environmental Dynamics Analyzer (MEDA) instrument on Mars 2020 over 415 Martian days (sols) (Ls = 6°–213°). Vortices are abundant (4.9 per sol with pressure drops >0.5 Pa correcting from gaps in coverage) and they peak at noon. At least one in every five vortices carries dust, and 75% of all vortices with Δp > 2.0 Pa are dusty. Seasonal variability was small but DDs were abundant during a dust storm (Ls = 152°–156°). Vortices are more frequent and intense over terrains with lower thermal inertia favoring high daytime surface-to-air temperature gradients. We fit measurements of winds and pressure during DD encounters to models of vortices. We obtain vortex diameters that range from 5 to 135 m with a mean of 20 m, and from the frequency of close encounters we estimate a DD activity of 2.0–3.0 DDs km−2 sol−1. A comparison of MEDA observations with a Large Eddy Simulation of Jezero at Ls = 45° produces a similar result. Three 100-m size DDs passed within 30 m of the rover from what we estimate that the activity of DDs with diameters >100 m is 0.1 DDs km−2sol−1, implying that dust lifting is dominated by the largest vortices in Jezero. At least one vortex had a central pressure drop of 9.0 Pa and internal winds of 25 ms−1. The MEDA wind sensors were partially damaged during two DD encounters whose characteristics we elaborate in detail.
Acceso Abierto
Decline in Water Ice Abundance in the Martian Mesosphere during Aphelion
(Europlanet, 2024-07-03) Toledo, D.; Rannou, P.; Apéstigue, Víctor; Rodríguez Veloso, Raúl; Arruego, I.; Martínez, Germán M.; Tamppari, L. K.; Munguira, A.; Lorenz, Ralph; Stcherbinine, Aurélien; Montmessin, F.; Sánchez Lavega, Agustín; Patel, P.; Viúdez Moreiras, Daniel; Hueso, R.; Bertrand, T.; Pla García, J.; Yela González, Margarita; De la Torre Juárez, M.; Rodríguez Manfredi, J. A.
Clouds play a crucial role in the past and current climate of Mars. Cloud particles impact the planet's energy balance and atmospheric dynamics, as well as influence the vertical distribution of dust particles through dust scavenging. This process of dust scavenging by clouds has significant consequences for the planet's water cycle. For example, regions in the atmosphere with insufficient quantities of dust particles, or condensation nuclei, can inhibit the formation of H2O clouds, leading to the presence of water vapor in excess of saturation [1]. Recent observations made by the MEDA Radiation and Dust Sensor (RDS) [2,3] have shown a marked decline in mesospheric cloud activity (above 35-40 km) when Mars is near its aphelion (within the Aphelion Cloud Belt-ACB season), notably occurring during solar longitudes (Ls) between Ls 70° and 80° [4] (see Figure 1). In order to investigate the possible factors leading to this decrease in water ice abundance, we used a one-dimensional cloud microphysical model [5,6], which includes the processes of nucleation, condensation, coagulation, evaporation, precipitation, and coalescence, and where the vertical mixing is parameterized using an eddy diffusion profile (Keddy). Combining cloud microphysics modeling with ground-based (Mars 2020 and InSight) and orbital observations (TGO and MRO) of clouds, water vapor, and temperature, we will discuss in this presentation the main factors controlling the water abundance in the Martian mesosphere during the ACB season.
Acceso Abierto
Drying of the Martian mesosphere during aphelion induced by lower temperatures
(Springer Nature, 2024-11-20) Toledo, D.; Rannou, P.; Apéstigue, Víctor; Rodríguez Veloso, Raúl; Rodríguez Manfredi, J. A.; Arruego, Ignacio; Martínez, Germán M.; Tamppari, L. K.; Munguira, A.; Lorenz, Ralph; Stcherbinine, Aurélien; Montmessin, F.; Sánchez Lavega, Agustín; Patel, P.; Smith, Michael D.; Lemmon, M. T.; Vicente Retortillo, Álvaro; Newman, C. E.; Viúdez Moreiras, Daniel; Hueso, R.; Bertrand, T.; Pla García, J.; Yela González, Margarita; De la Torre Juárez, M.; Ministerio de Ciencia e Innovación (MICINN); Jet Propulsion Laboratory (JPL); National Aeronautics and Space Administration (NASA); Gobierno Vasco; Agencia Estatal de Investigación (AEI); Unidad de Excelencia Científica María de Maeztu Instituto de Astrofísica de Cantabria, MDM-2017-0765
The formation of water ice clouds or hazes on Mars imposes substantial limitations on the vertical transport of water into the middle-upper atmosphere, impacting the planet’s hydrogen loss. Recent observations made by the Mars Environmental Dynamics Analyzer instrument onboard Mars 2020 Perseverance rover have shown a marked decline in water ice abundance within the mesosphere (above 35-40 km) when Mars is near its aphelion (near the northern summer solstice), notably occurring during solar longitudes (Ls) between Ls 70∘ and 80∘. Orbital observations around the same latitudes indicate that temperatures between ~ 30-40 km reach a minimum during the same period. Using cloud microphysics simulations, we demonstrate that this decrease in temperature effectively increases the amount of water cold-trapped at those altitudes, confining water ice condensation to lower altitudes. Similarly, the reinforcement of the cold trap induced by the lower temperatures results in significant reductions in the water vapor mixing ratio above 35–40 km, explaining the confinement of water vapor observed around aphelion from orbiters.
Restringido
The DREAMS experiment flown on the ExoMars 2016 mission for the study of Martian environment during the dust storm season
(Elsevier, 2018-02-01) Bettanini, C.; Esposito, F.; Debei, S.; Molfese, C.; Colombatti, G.; Aboudan, A.; Brucato, J. R.; Cortecchia, F.; Di Achille, G.; Guizzo, G. P.; Friso, Enrico; Ferri, F.; Marty, Laurent; Mennella, V.; Molinaro, R.; Schipani, P.; Silvestro, S.; Mugnuolo, R.; Pirrotta, S.; Marchetti, Edoardo; Ari-Matti, H.; Montmessin, F.; Wilson, Colin; Arruego, I.; Abbaki. S.; Apéstigue, V.; Bellucci, G.; Berthelier, J. J.; Calcutt, S.; Forget, F.; Genzer, María; Gilbert, Pierre; Haukka, H.; Jiménez Martín, Juan José; Jiménez, Salvador; Josset, J. L.; Karatekin, Özgür; Landis, G.; Lorenz, Ralph; Martínez Oter, J.; Möhlmann, D.; Moirin, D.; Palomba, E.; Patel, M.; Pommereau, J. P.; Popa, C. I.; Rafkin, Scot C. R.; Rannou, P.; Rennó, N. O.; Schmidt, Walter; Simoes, F.; Spiga, A.; Valero, F.; Vázquez, L.; Apéstigue, Víctor; Agenzia Spaziale Italiana (ASI); Istituto Nazionale di Astrofisica (INAF)
"The DREAMS (Dust characterization, Risk assessment and Environment Analyser on the Martian Surface) instrument on Schiaparelli lander of ExoMars 2016 mission was an autonomous meteorological station designed to completely characterize the Martian atmosphere on surface, acquiring data not only on temperature, pressure, humidity, wind speed and its direction, but also on solar irradiance, dust opacity and atmospheric electrification; this comprehensive set of parameters would assist the quantification of risks and hazards for future manned exploration missions mainly related to the presence of airborne dust. Schiaparelli landing on Mars was in fact scheduled during the foreseen dust storm season (October 2016 in Meridiani Planum) allowing DREAMS to directly measure the characteristics of such extremely harsh environment. DREAMS instrument’s architecture was based on a modular design developing custom boards for analog and digital channel conditioning, power distribution, on board data handling and communication with the lander. The boards, connected through a common backbone, were hosted in a central electronic unit assembly and connected to the external sensors with dedicated harness. Designed with very limited mass and an optimized energy consumption, DREAMS was successfully tested to operate autonomously, relying on its own power supply, for at least two Martian days (sols) after landing on the planet. A total of three flight models were fully qualified before launch through an extensive test campaign comprising electrical and functional testing, EMC verification and mechanical and thermal vacuum cycling; furthermore following the requirements for planetary protection, contamination control activities and assay sampling were conducted before model delivery for final integration on spacecraft. During the six months cruise to Mars following the successful launch of ExoMars on 14th March 2016, periodic check outs were conducted to verify instrument health check and update mission timelines for operation. Elaboration of housekeeping data showed that the behaviour of the whole instrument was nominal during the whole cruise. Unfortunately DREAMS was not able to operate on the surface of Mars, due to the known guidance anomaly during the descent that caused Schiaparelli to crash at landing. The adverse sequence of events at 4 km altitude anyway triggered the transition of the lander in surface operative mode, commanding switch on the DREAMS instrument, which was therefore able to correctly power on and send back housekeeping data. This proved the nominal performance of all DREAMS hardware before touchdown demonstrating the highest TRL of the unit for future missions. The spare models of DREAMS are currently in use at university premises for the development of autonomous units to be used in cubesat mission and in probes for stratospheric balloons launches in collaboration with Italian Space Agency."
Acceso Abierto
Vortices and Dust Devils on Jezero Crater, Mars: inner thermal structure and dependence on surface properties
(EGU General Assembly, 2024-05-16) Hueso, R.; Munguira, A.; Newman, C. E.; Martínez, Germán M.; Sánchez Lavega, Agustín; Del Río Gaztelurrutia, T.; Toledo, D.; Apéstigue, Víctor; Arruego, Ignacio; Pla García, J.; Lemmon, M. T.; Lorenz, Ralph; Vicente Retortillo, Álvaro; Navarro López, Sara; Stott, Alexander; Murdoch, N.; Gillier, M.; De la Torre Juárez, M.; Rodríguez Manfredi, J. A.