Variabilidad estacional e interanual de la radiación solar en las coordenadas de aterrizaje de Spirit, Opportunity y Curiosity

Abstract

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. Key words: Solar radiation; Mars Exploration Rovers; Mars Science Laboratory; opacity, dust; radiative transfer model; Mars exploration.Variabilidad estacional e interanual de la radiación solar en las coordenadas de aterrizaje de Spirit, Opportunity y Curiosity ResumenEl presente artículo está dedicado a la caracterización del entorno radiativo en los lugares de aterrizaje de las misiones de la NASA de Mars Exploration Rover (MER) y de Mars Science Laboratory (MSL). Se hace uso de las opacidades obtenidas a partir de imágenes directas del Sol y de nuestro modelo de transferencia radiativa COMIMART con el fin de analizar la variabilidad estacional e interanual de la irradiación diaria en las coordenadas de aterrizaje de los MER y de MSL. Asimismo, se analiza el comportamiento de las componentes directa y difusa de la radiación solar en estos lugares de aterrizaje. IntroductionThe study of the radiation environment at the Martian surface is important because of the role that solar radiation plays in constraining the habitability of Mars and in driving its atmospheric dynamics. Ultraviolet radiation has the potential to damage the DNA (Córdoba-Jabonero et al.,, 2003) while solar radiation feeds atmospheric thermodynamic processes occurring in the first meters of the Martian atmosphere, the so-called planetary boundary layer.In this article we study the variability of the daily irradiation at the surface (also called insolation and defined as the total amount of solar energy received during one sol) at the landing sites of MER Spirit (14.57ºS, 175.48ºE) and Opportunity (1.95°S, 354.47°E) and MSL Curiosity (4.59ºS, 137.44ºE) rovers on seasonal and interannual time scales. We also discuss the variability of the diffuse and direct components of the insolation at these three locations.In section 1 we review several efforts to retrieve dust opacity both from satellites and ground measurements, and we show the opacities at the Spirit, Opportunity and Curiosity landing sites. In section 2 we describe our COmplutense and MIchigan MArs Radiative Transfer model (COMIMART) and perform sensitivity studies to validate the assumption of using atmospheric optical depths as dust opacities. In section 3 we analyze the behavior of the total radiation at the top of the atmosphere. In section 4 we characterize the radiative environment at the three selected landing sites. Finally, we highlight our main conclusions in section 5.

Catalytic/Protective Properties of Martian Minerals and Implications for Possible Origin of Life on Mars

“…The current very thin (~6 mbar) atmosphere of Mars, dominated by carbon dioxide (CO 2 ), is capable of absorbing photons of wavelengths shorter than 190 nm [47,159], with the absorption cross section for carbon dioxide of the order of 10 −23 cm 2 at 195 nm, 10 −18 cm 2 in the range 130–150 nm, and 10 −17 cm 2 in the range 98–120 nm [159,160], and also does not allow efficient penetration of X-rays [11,161,162]. Thus, only mid- and near UV may cause degradation of organic compounds at the surface, and the respective fluxes have been both modelled and measured in situ (for more detail, see references [46,47,48,49,50,163]).…”

“…Beyond the transformation that occurred inside the SAM instrument, the original material might have been subjected to previous processing acting over geological time throughout Mars’ history, caused by several factors that may include: (i) Deposition and subsequent diagenesis in lake sediments from water, heat, and pressure; (ii) physical weathering by dissolution, water, and wind agitation and fragmentation, particle collisions, abrasion, glacial processes, volcanism, and impact shocks; and (iii) chemical weathering through irradiation and oxidation degradation [43]. The most dramatic degradation should have occurred during the most recent Amazonian period, due to the shutting down of the planet geodynamo and the erosion of the atmosphere by the solar wind, which resulted in high irradiation at the surface by galactic cosmic rays, energetic solar protons, and ultraviolet (UV) photons [44,45,46,47,48,49,50,51], along with the formation of strong oxidants in the soil driven by photochemical processes [52,53,54]. Currently, Mars is not very geologically active, so the primary mechanism of physical weathering is aeolian erosion caused by the collision of particles moved by the wind.…”

DEM Based Study on Shielded Astronomical Solar Radiation and Possible Sunshine Duration under Terrain Influences on Mars by Using Spectral Methods

“…Based on the calculation model of SASR on the sloped surface, we can reconsider the corresponding Equations and build the distributed model (or subparagraph integral mathematical model) to calculate PSD and SASR under terrain relief on Mars. Based on the existing theoretical model of solar radiation on Mars [1,2,9,10,26,27,30,32,[37][38][39] and the Astronomical theory on Mars, combining with the theoretical model of solar radiation on Earth [6,8,11,12,14,15,17,63,64,91,[94][95][96][97][98][99][100][101], the SASR model which is suitable for Mars is proposed. It can be given by the following steps:…”

Overview of the main radiation transport codes

“…The COMIMART-MC, COmplutense and Michigan Mars Radiative Transfer model -Monte Carlo, is a Monte Carlo code to calculate solar irradiance that reaches the surface of Mars in the spectral range from the ultraviolet (UV) to the near infrared (NIR), and it has been developed and validated under different scenarios (Retortillo et al, 2015(Retortillo et al, , 2016(Retortillo et al, , 2017. The model includes up-to-date wavelength-dependent radiative properties of dust, water, ice clouds and gas molecules.…”

“…It is worth exploring the role of dust in the Martian atmosphere (Retortillo et al, 2017), as it is quite a relevant aspect to consider when trying to reach the goal of improving these radiation transport codes. This element may play a very important role under certain circumstances, particularly because a dust storm may be so intense that it affects the whole planet.…”