Un nuevo modelo de transferencia radiativa en Marte : aplicaciones utilizando medidas in situ

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Físicas, Departamento de Física de la Tierra, Astronomía y Astrofísica II, leída el 19-07-2017El estudio del entorno radiativo en la superficie marciana es fundamental para la comprensión y para una mejor caracterización de los procesos físicos de la atmósfera y el clima del planeta, así como para determinar el impacto biológico de la radiación ultravioleta. Estos dos objetivos son prioritarios en las misiones actuales y futuras a Marte debido a sus implicaciones en la preparación para la exploración humana del planeta. Debido a la importancia de la radiación solar, es necesario poder contar con modelos de transferencia radiativa precisos. Esta precisión es especialmente importante en el cálculo de las radiancias y de los flujos solares en la superficie, los cuales son cantidades fundamentales para caracterizar el entorno radiativo en la superficie y para maximizar el retorno científico de las misiones a Marte. Las simulaciones precisas de la radiación solar en la superficie marciana no sólo requieren modelos de transferencia radiativa detallados y validados, sino también un conocimiento exacto de las propiedades radiativas de los componentes atmosféricos, entre los que el polvo en suspensión es particularmente importante. La combinación de los resultados de los modelos y de las medidas de radiación solar desde la superficie marciana permiten la obtención de las propiedades del polvo en suspensión. El sensor de radiación ultravioleta (UVS) de REMS (Rover Environmental Monitoring Station), a bordo de la misión MSL (Mars Science Laboratory) ha estado midiendo la radiación solar en superficie por primera vez en seis bandas entre 200 y 380 nm. Estas medidas pueden proporcionar información sobre las propiedades y la variabilidad temporal del polvo en suspensión. El rango espectral de este sensor se verá ampliado en misiones futuras, tales como MetNet, que contará con un Sensor de Irradiancia Solar (MetSIS). Otras misiones futuras, tales como ExoMars 2020 y Mars 2020, también contarán con un RDS (Radiation and Dust Sensor)...The study of the radiative environment at the Martian surface is paramount to understand and better characterize the physical processes of the atmosphere and the climate of the planet, as well as to determine the biological impact of ultraviolet radiation. These two objectives are a priority in current and future Mars missions due to their implications in the preparation for the human exploration of the planet. Due to the importance of solar radiation, accurate radiative transfer models are needed. Accuracy is particularly important for the calculation of the solar radiances and fluxes at the surface, which are key quantities to characterize the radiative environment at the surface and to maximize the scientific return of the missions to Mars. Accurate simulations of the solar radiation at the Martian surface require not only comprehensive and validated radiative transfer models, but also an accurate knowledge of the radiative properties of the atmospheric components, suspended dust being especially important. The combination of model results and solar radiation measurements from the Martian surface can allow the retrieval of the dust aerosol properties. The Ultraviolet Sensor (UVS) of the Rover Environmental Monitoring Station (REMS) on board the Mars Science Laboratory (MSL) mission has been measuring solar radiation at the surface of Mars for the first time in six bands between 200 and 380 nm. These measurements can provide information about the properties and temporal variability of the suspended dust. The spectral range of this sensor will be extended in future missions, such as MetNet, which will contain a Solar Irradiance Sensor (MetSIS). Other future missions, such as ExoMars 2020 and Mars 2020, will also carry a Radiation and Dust Sensor (RDS)...Depto. de Física de la Tierra y AstrofísicaFac. de Ciencias FísicasTRUEunpu

Determination of dust aerosol particle size at Gale Crater using REMS UVS and Mastcam measurements

We calculate the seasonal and interannual variation in dust aerosol particle size above Gale Crater during the first 1413 Martian solar days (sols = 24.6 h) of the Mars Science Laboratory mission. Measurements of UV radiation made by the Rover Environmental Monitoring Station in combination with atmospheric opacities retrieved from the Mastcam instrument are used for the calculations. Our results indicate that the dust effective radius varies significantly with season, ranging from ~0.6 μm during the low opacity season (Ls = 60°â 140°) to ~2 μm during the high opacity season (Ls = 180°â 360°). Our results suggest that Gale Crater is affected by dust events of high aerosol content originated at various distances from it. Our results improve the accuracy of estimations of ultraviolet radiation fluxes at the Martian surface. Moreover, our results have important implications because the lifetime of suspended dust and its ability to nucleate clouds are affected by particle size.Plain Language SummaryThe Martian atmosphere transports large amounts of dust, which interacts strongly with solar and infrared radiation. The large spatial and temporal variability in atmospheric dust load creates complex feedbacks connecting dust lifting with the evolving atmospheric circulations. The size of suspended aerosols affects the surface and atmospheric heating rates, influencing the Martian climate. In this work, we have calculated the dust aerosol particle size above Gale Crater during the first 1413 sols of the Mars Science Laboratory (MSL) mission using measurements of UV radiation made for the first time from the surface of Mars. Our results indicate that the dust effective radius varies significantly with season, ranging from ~0.6 μm during the clear season to ~2 μm during the dusty season. Our results suggest that Gale Crater is affected by dust events of high aerosol content originated at various distances from it. Our results are important because the lifetime of suspended dust and its ability to nucleate clouds are affected by the particle size.Key PointsWe have developed a novel methodology to retrieve dust aerosol particle size at Gale Crater using Mars Science Laboratory dataThe retrieved dust effective radii range from 0.6 μm during the clear aphelion season to 2 μm during the dusty perihelion seasonOur results improve the estimation of ultraviolet radiation fluxes at the Martian surfacePeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137189/1/grl55782-sup-0001-2017GL072589-SI.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137189/2/grl55782_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137189/3/grl55782.pd

Seasonal and interannual variability of solar radiation at Spirit, Opportunity and Curiosity landing sites

In this article we characterize the radiative environment at the landing sites of NASA's Mars Exploration Rover (MER) and Mars Science Laboratory (MSL) missions. We use opacity values obtained at the surface from direct imaging of the Sun and our radiative transfer model COMIMART to analyze the seasonal and interannual variability of the daily irradiation at the MER and MSL landing sites. In addition, we analyze the behavior of the direct and diffuse components of the solar radiation at these landing sites

Detection and Degradation of Adenosine Monophosphate in Perchlorate-Spiked Martian Regolith Analogue, by Deep-Ultraviolet Spectroscopy

The search for organic biosignatures on Mars will depend on finding material protected from the destructive ambient radiation. Solar ultraviolet can induce photochemical degradation of organic compounds, but certain clays have been shown to preserve organic material. We examine how the SHERLOC instrument on the upcoming Mars 2020 mission will use deep-ultraviolet (UV) (248.6 nm) Raman and fluorescence spectroscopy to detect a plausible biosignature of adenosine 5′-monophosphate (AMP) adsorbed onto Ca-montmorillonite clay. We found that the spectral signature of AMP is not altered by adsorption in the clay matrix but does change with prolonged exposure to the UV laser over dosages equivalent to 0.2–6 sols of ambient martian UV. For pure AMP, UV exposure leads to breaking of the aromatic adenine unit, but in the presence of clay the degradation is limited to minor alteration with new Raman peaks and increased fluorescence consistent with formation of 2-hydroxyadenosine, while 1 wt % Mg perchlorate increases the rate of degradation. Our results confirm that clays are effective preservers of organic material and should be considered high-value targets, but that pristine biosignatures may be altered within 1 sol of martian UV exposure, with implications for Mars 2020 science operations and sample caching

Predicciones probabilistas de velocidad de viento mediante un sistema multifísica y multianálisis de predicción por conjuntos

Ponencia presentada en: IX Congreso de la Asociación Española de Climatología celebrado en Almería entre el 28 y el 30 de octubre de 2014.[ES]El desarrollo de la energía eólica y su importancia en la producción eléctrica ha conllevado la mejora de los métodos de predicción de velocidad del viento y los sistemas de predicción por conjunto a corto plazo (SPC) pueden jugar un papel importante en ello. Este estudio presenta resultados de velocidad del viento a 10 m en la Península Ibérica obtenidos de un SPC multifísica. El modelo está basado en el Weather Research and Forecasting (WRF) model version 3.3. El SPC consta de 10 miembros compuestos de dos conjuntos diferentes de condiciones iniciales y de contorno, y 5 conjuntos diferentes de parametrizaciones subrejilla físicas. Se muestran diversos resultados de verificación tanto deterministas como probabilistas que permiten extraer conclusiones del diseño del SPC. En cuanto a los deterministas, resultados de sesgo, correlaciones espaciales y errores cuadráticos medios se exponen espacialmente, evaluando la habilidad del modelo en la predicción de la velocidad del viento a 10m en la Península Ibérica. Los resultados probabilistas se muestran en términos de histogramas de rango del sistema en la predicción de la velocidad del viento en diferentes áreas de la Península Ibérica. Se pone de manifiesto cómo las diferentes condiciones climáticas peninsulares producen gran variabilidad en los estadísticos de validación, lo cual habría de tenerse en cuenta a la hora de validar un modelo sobre un área con gran diversidad climática como es la Península Ibérica.[EN]The rapid expansion of wind energy and its increasing importance in power production have necessitated improved methods for forecasting wind speeds and the short-range Ensemble Prediction Systems (EPS) could potentially play a major role. This study presents results of 10m wind speed over the Iberian Peninsula obtained from a multi-physic EPS. The EPS is based on the Weather Research and Forecasting (WRF) model version 3.3. The EPS have 10 members, which are composed of two different sets of initial and boundary conditions, and 5 different sets of subgrid scale physics parameterizations. Several deterministic and probabilistic verification results are shown. These results allow to establish the EPS design quality. Results of bias, spatial correlations and root mean squared errors are displayed, evaluating the models skillful for predicting 10m wind speed over the Iberian Peninsula. The probabilistic results are shown by means of rank histograms. The results show the model skilful in forecasting wind speed in different areas of Iberia, emphasizing how diverse peninsular climatic conditions promote high variability in validation skill scores. This fact must be considered when a model is validated over areas with high climatic diversity such as the Iberian Peninsula

Spatial, Seasonal, and Solar Cycle Variations of the Martian Total Electron Content (TEC): Is the TEC a Good Tracer for Atmospheric Cycles?

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.We analyze 10 years of Mars Express total electron content (TEC) data from the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instrument. We describe the spatial, seasonal, and solar cycle behavior of the Martian TEC. Due to orbit evolution, data come mainly from the evening, dusk terminator and postdusk nightside. The annual TEC profile shows a peak at Ls = 25–75° which is not related to the solar irradiance variation but instead coincides with an increase in the thermospheric density, possibly linked with variations in the surface pressure produced by atmospheric cycles such as the CO or water cycles. With the help of numerical modeling, we explore the contribution of the ion species to the TEC and the coupling between the thermosphere and ionosphere. These are the first observations which show that the TEC is a useful parameter, routinely measured by Mars Express, of the dynamics of the lower-upper atmospheric coupling and can be used as tracer for the behavior of the thermosphere.©2018. The Authors.B. S. -C. and M. L. acknowledge support through STFC grant ST/N000749/1. ESA-ESTEC Faculty and Europlanet funding are also gratefully acknowledged. MEX MARSIS RDR and EDR data can be downloaded from the ESA-PSA archive, TIMED-SEE data at the University of Colorado's website (http://lasp.colorado.edu/lisird/index.html), REMS data at the NASA Planetary Data System (http://atmos.nmsu.edu/PDS/data/mslrem_1001/DATA/), the MCD model at the Mars Climate Database web interface (http://www-mars.lmd.jussieu.fr/mars/access.html), and the IPIM model at the IRAP CDPP web interface (http://transplanet.irap.omp.eu/)

Seasonal Variations in Atmospheric Composition as Measured in Gale Crater, Mars

All MSL data used in this manuscript (REMS and SAM) are freely available on NASA's Planetary Data System (PDS) Geosciences Node, from within 6 months after receipt on Earth (http://pds‐geosciences.wustl.edu/missions/msl/). The mixing ratios developed and presented in this paper are available at a publicly available archive (dataverse.org: doi.org/10.7910/DVN/CVUOWW) as cited within the manuscript. The successful operation of the Curiosity rover and the SAM instrument on Mars is due to the hard work and dedication of hundreds of scientists, engineers, and managers over more than a decade. Essential contributions to the successful operation of SAM on Mars and the acquisition of SAM data were provided by the SAM development, operations, and test bed teams. The authors gratefully thank the SAM and MSL teams that have contributed in numerous ways to obtain the data that enabled this scientific work. We also thank NASA for the support of the development of SAM, SAM data analysis, and the continued support of the Mars Science Laboratory mission. The contribution of F. Lefèvre was supported by the Programme National de Planétologie (PNP). R. Navarro‐Gonzalez acknowledges support from the Universidad Nacional Autónoma de México (PAPIIT IN111619). LPI is operated by USRA under a cooperative agreement with the Science Mission Directorate of the National Aeronautics and Space Administration. We thank members of the SAM and larger MSL team for insightful discussions and support. In particular, we thank R. Becker and R. O. Pepin for careful review of data analysis and interpretation. We thank M. D. Smith for discussion of CRISM CO measurements. We thank A. Brunner, M. Johnson, and M. Lefavor for their development of customized data analysis tools used here and in other SAM publications.Peer reviewedPublisher PD

Twilight Mesospheric Clouds in Jezero as Observed by MEDA Radiation and Dust Sensor (RDS)

The Mars Environmental Dynamics Analyzer instrument, on board NASA's Mars 2020 Perseverance rover, includes a number of sensors to characterize the Martian atmosphere. One of these sensors is the Radiation and Dust Sensor (RDS) that measures the solar irradiance at different wavelengths and geometries. We analyzed the RDS observations made during twilight for the period between sol 71 and 492 of the mission (Ls 39°–262°, Mars Year 36) to characterize the clouds over the Perseverance rover site. Using the ratio between the irradiance at zenith at 450 and 750 nm, we inferred that the main constituent of the detected high-altitude aerosol layers was ice from Ls = 39°–150° (cloudy period), and dust from Ls 150°–262°. A total of 161 twilights were analyzed in the cloudy period using a radiative transfer code and we found: (a) signatures of clouds/hazes in the signals in 58% of the twilights; (b) most of the clouds had altitudes between 40 and 50 km, suggesting water ice composition, and had particle sizes between 0.6 and 2 µm; (c) the cloud activity at sunrise is slightly higher that at sunset, likely due to the differences in temperature; (d) the time period with more cloud detections and with the greatest cloud opacities is during Ls 120°–150°; and (e) a notable decrease in the cloud activity around aphelion, along with lower cloud altitudes and opacities. This decrease in cloud activity indicates lower concentrations of water vapor or cloud condensation nuclei (dust) around this period in the Martian mesosphere.This work has been funded by the Spanish Ministry of Economy and Competitiveness, through the projects no. ESP2014-54256-C4-1-R (also ESP2014-54256-C4-2-R, ESP2014-54256-C4-3-R, and ESP2014-54256-C4-4-R), Spanish Ministry of Science, Innovation and Universities, projects no. ESP2016-79612-C3-1-R (also ESP2016-79612-C3-2-R and ESP2016-79612-C3-3-R), Spanish Ministry of Science and Innovation/State Agency of Research (10.13039/501100011033), projects no. PID2021-126719OB-C41, ESP2016-80320-C2-1-R, RTI2018-098728-B-C31 (also RTI2018-098728-B-C32 and RTI2018-098728-B-C33), RTI2018-099825-B-C31. RH and ASL were supported by the Spanish project PID2019-109467GB-I00 funded by MCIN/AEI/10.13039/50110001103 and by Grupos Gobierno Vasco IT1742-22. The US co-authors performed their work under sponsorship from NASA’s Mars 2020 project, from the Game Changing Development programme within the Space Technology Mission Directorate and from the Human Exploration and Operations Directorate. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). G.M. acknowledges JPL funding from USRA Contract Number 1638782. ML is supported by contract 15-712 from Arizona State University and 1607215 from Caltech-JPL. A. V-R. is supported by the Comunidad de Madrid Project S2018/NMT-4291 (TEC2SPACE-CM)

Dust Lifting Through Surface Albedo Changes at Jezero Crater, Mars

We identify temporal variations in surface albedo at Jezero crater using first-of-their-kind high-cadence in-situ measurements of reflected shortwave radiation during the first 350 sols of the Mars 2020 mission. Simultaneous Mars Environmental Dynamics Analyzer (MEDA) measurements of pressure, radiative fluxes, winds, and sky brightness indicate that these albedo changes are caused by dust devils under typical conditions and by a dust storm at Ls ∼ 155°. The 17% decrease in albedo caused by the dust storm is one order of magnitude larger than the most apparent changes caused during quiescent periods by dust devils. Spectral reflectance measurements from Mastcam-Z images before and after the storm indicate that the decrease in albedo is mainly caused by dust removal. The occurrence of albedo changes is affected by the intensity and proximity of the convective vortex, and the availability and mobility of small particles at the surface. The probability of observing an albedo change increases with the magnitude of the pressure drop (ΔP): changes were detected in 3.5%, 43%, and 100% of the dust devils with ΔP 2.5 Pa and ΔP > 4.5 Pa, respectively. Albedo changes were associated with peak wind speeds above 15 m·s−1. We discuss dust removal estimates, the observed surface temperature changes coincident with albedo changes, and implications for solar-powered missions. These results show synergies between multiple instruments (MEDA, Mastcam-Z, Navcam, and the Supercam microphone) that improve our understanding of aeolian processes on Mars.This research has been funded by the Comunidad de Madrid Project S2018/NMT-4291 (TEC2SPACE-CM), by the Spanish State Research Agency (AEI) Project MDM-2017-0737 Unidad de Excelencia “María de Maeztu”- Centro de Astrobiología (CSIC/INTA), by the Spanish Ministry of Science and Innovation (MCIN)/State Agency of Research (10.13039/501100011033) project RTI2018-098728-B-C31, and by the project PID2021-126719OB-C41, funded by MCIN/AEI/10.13039/501100011033/FEDER, UE. RH, ASL and AM were supported by Grant PID2019-109467GB-I00 funded by MCIN/AEI/10.13039/501100011033/. Part of the research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). We want to thank J. Bell for processing Mastcam-Z projections showing the entire TIRS FOV and to S. Navarro and the entire team for generating the processed wind sensor data