The cryosphere component provides the most reliable and insightful indications of any planet’s climate dynamics.Using data from the Compact Reconnaissance Imaging Spectrometer for Mars(CRISM),we develop a novel appro...The cryosphere component provides the most reliable and insightful indications of any planet’s climate dynamics.Using data from the Compact Reconnaissance Imaging Spectrometer for Mars(CRISM),we develop a novel approach to determining the broadband Visible and Near Infrared(VNIR)albedo of the Martian surface.This study focuses on albedo changes in the McMurdo crater,part of Mars’s south polar layer deposits.We compare seasonal and interannual variations of the McMurdo surface albedo before,during,and after the Global Dust Storm(GDS)of Martian Year(MY)34.As the seasons progressed from spring to summer,the mean albedo in MY 32 and 34 plunged by over 40%,by about 35%in MY 33,and by slightly more than 30%in MY 35.Compared interannually,however,mean albedo values within both seasons(spring and summer)exhibited no significant differences in those same years.Notably,interannual albedo difference maps reveal albedo variation of more than±0.3 in certain regions of the crater.Considering only snow-covered pixels,interannual albedo differences suggest that Mars dust had a pervasive impact on Mars’s cryosphere.Variations in maximum and minimum albedo values as high as 0.5 were observed,depending upon differences in the dust levels in Martian snow/ice.The maximum and the minimum snow albedo values were lowest in MY 34,indicating the effect of the intense dust storm event that year.The average snow albedo decreased from 0.45 in MY 32 to 0.40 in MY 33 and to 0.33 in MY 34,and then rose back to 0.40 in MY 35.This trajectory suggests a temporary deposition of dust,partially reversed after the GDS by self-cleaning mechanisms(local aeolian process and CO_(2)sublimation/deposition cycle).展开更多
The InSight(Interior Exploration using Seismic Investigations,Geodesy,and Heat Transport)mission has recorded continuous ambient noise signals with many spectral peaks since its landing in 2018.The majority of these p...The InSight(Interior Exploration using Seismic Investigations,Geodesy,and Heat Transport)mission has recorded continuous ambient noise signals with many spectral peaks since its landing in 2018.The majority of these peaks are modes produced by instrumental vibrations and are associated with environmental factors,such as temperature and wind energy fluctuations.Understanding how these modes react under various conditions is crucial because it aids in identifying their origins.In this study,we analyzed the three-component spectra of InSight recordings from sols 184–738 and obtained the horizontal-to-vertical spectral ratio(HVSR,also known as H/V)curves for different time intervals.The primary modes,such as those at 3.3 and 4.1 Hz,exhibited different behaviors,suggesting diverse origins.Some modes were sensitive to low temperature and some were sensitive to high temperature.Additionally,we investigated the influence of wind and temperature on the H/V curve.The peak frequency was mainly affected by temperature,whereas the H/V value was not associated with the temperature or wind only.Characterizing these modes and elucidating their origins are significant for processing signals from InSight and can provide valuable guidance for designing future planetary seismometers.展开更多
In high mountainous areas, the development and distribution of alpine permafrost is greatly affected by macro- and mi- cro-topographic factors. The effects of latitude, altitude, slope, and aspect on the distribution ...In high mountainous areas, the development and distribution of alpine permafrost is greatly affected by macro- and mi- cro-topographic factors. The effects of latitude, altitude, slope, and aspect on the distribution of permafrost were studied to under- stand the dislribution patterns of permafrost in Wenquan on the Qinghai-Tibet Plateau. Cluster and correlation analysis were per- formed based on 30 m Global Digital Elevation Model （GDEM） data and field data obtained using geophysical exploration and borehole drilling methods. A Multivariate Adaptive Regression Spline model （MARS） was developed to simulate permafrost spa- tial distribution over the studied area. A validation was followed by comparing to 201 geophysical exploration sites, as well as by comparing to two other models, i.e., a binary logistic regression model and the Mean Annual Ground Temperature model （IVlAGT）. The MARS model provides a better simulation than the other two models. Besides the control effect of elevation on permafrost distribution, the MARS model also takes into account the impact of direct solar radiation on permafrost distribution.展开更多
The principal moments of inertia(PMIs)with the principal axes are usually taken as the dynamic figure parameters of Mars;they can be deduced from satellite-observed degree-two gravitational potentials in recent global...The principal moments of inertia(PMIs)with the principal axes are usually taken as the dynamic figure parameters of Mars;they can be deduced from satellite-observed degree-two gravitational potentials in recent global gravity models and from the dynamic ellipticities resulting from precession observations.These PMIs are natural and significant for the geodetic,geophysical,and geodynamic problems of Mars,which are functions of internal density distributions.In this study,a closed and concise formula for determining the PMIs of the entire planet and its core was developed based on the second invariants of gravity and a multipole expansion.We deduced the polar oblateness J^(2)and the equatorial ellipticity J_(22)of Mars to be 1.9566×10^(−3)and 6.3106×10^(−5),respectively.The preferred principal moments of inertia of Mars are A=2.66589×1036 kg·m^(2),B=2.66775×10^(36)kg·m^(2),and C=2.68125×10^(36)kg·m^(2).These values indicate that Mar is slightly triaxial.The equatorial principal moment of inertia of the Martian core is 1.46008×10^(35)kg·m^(2),accounting for~5.47%of the planet’s PMI;this result is critical for investigating the density and size of the core of Mars,and the planet’s free core nutation.展开更多
The Mars Orbiter MAGnetometer(MOMAG)is a scientific instrument onboard the orbiter of China’s first mission for Mars—Tianwen-1.Since November 13,2021,it has been recording magnetic field data from the solar wind to ...The Mars Orbiter MAGnetometer(MOMAG)is a scientific instrument onboard the orbiter of China’s first mission for Mars—Tianwen-1.Since November 13,2021,it has been recording magnetic field data from the solar wind to the magnetic pile-up region surrounding Mars.Here we present its in-flight performance and first science results,based on its first one and one-half months’data.Comparing these early MOMAG observations to the magnetic field data in the solar wind from NASA’s Mars Atmosphere and Volatile EvolutioN(MAVEN)mission,we report that the MOMAG magnetic field data are at the same level in magnitude,and describe the same magnetic structures with similar variations in three components.We recognize 158 clear bow shock(BS)crossings in these MOMAG data;their locations match well statistically with the modeled average BS.We also identify and compare five pairs of datasets collected when Tianwen-1’s orbiter and the MAVEN probe made simultaneous BS crossings.These BS crossings confirm the global shape of modeled BS,as well as the south-north asymmetry of the Martian BS.Two cases presented in this paper suggest that the BS is probably more dynamic at flank than near the nose.So far,MOMAG performs well,and provides accurate magnetic field vectors.MOMAG is continuously scanning the magnetic field surrounding Mars.Data from MOMAG’s measurements complement data from MAVEN and will undoubt edly advance our understanding of the plasma environment of Mars.展开更多
The pitch angle distributions of ions and electrons can be affected by various processes;thus,they can serve as an important indicator of the physical mechanisms driving the dynamics of space plasmas.From observations...The pitch angle distributions of ions and electrons can be affected by various processes;thus,they can serve as an important indicator of the physical mechanisms driving the dynamics of space plasmas.From observations from the Mars Ion and Neutral Particle Analyzer onboard the Tianwen-1 orbiter,we calculated the pitch angle distributions of protons in the Martian induced magnetosphere by using information from the magnetohydrodynamically simulated magnetic field,and we statistically analyzed the spatial occurrence pattern of different types of pitch angle distributions.Even though no symmetrical features were seen in the dataset,we found the dominance of the field-aligned distribution type over the energy range from 188 to 6232 eV.Maps of the occurrence rate showed the preferential presence of a trapped-like distribution at the lower altitudes of the surveyed nightside region.Although our results are more or less restricted by the adopted magnetic field,they indicate the complexity of the near-Mars proton pitch angle distributions and infer the possibility of wave–particle interactions in the Martian induced magnetosphere.展开更多
This review article aims to gather differences and similarities between planet Mars and planet Earth to determine the necessities for the proper growth and development of the neonatal brain. Factors such as Environmen...This review article aims to gather differences and similarities between planet Mars and planet Earth to determine the necessities for the proper growth and development of the neonatal brain. Factors such as Environmental, Nutritional, Social, Stress, and Education are juxtaposed to understand the difference between pediatric neurodevelopment on both planets. The variation between each factor was analyzed to determine how significant the impact is on neurodevelopment for children. The factors to be discussed were generated based on extensive research on what is most important for proper early neurodevelopment. The five factors are the main categories branched out into subcategories to delve into more detail regarding neurodevelopment. Factors may vary based on the location on each planet, but the best average was cultivated to create a fair evaluation of the differences. Although each factor influences a different part of the brain, each factor (Environmental, Nutritional, Social, Stress, and Education) is equally vital for development anatomy and physiology of the brain.展开更多
Seismometers of the InSight probe(Interior Exploration using Seismic Investigation,Geodesy and Heat Transport)currently operating on Mars have recorded not only seismic events but also high-frequency non-seismic perio...Seismometers of the InSight probe(Interior Exploration using Seismic Investigation,Geodesy and Heat Transport)currently operating on Mars have recorded not only seismic events but also high-frequency non-seismic periodic signals that appear to have been induced by variations in the Martian environment and the hardware.Here,we report an observation of a long-period signal with a dominant period of~20 s from Martian solar days(Sol)800 to Sol 1,000.This 20-s signal is detected mostly at quiet nighttime—from22:00 to 04:00 LMST(Local Mean Solar Time)—at the InSight landing site.The measurement of the particle motion suggests that this linearly polarized signal focuses on the horizontal plane with an angle of~30°from the north.By examining the temporal variation of the signal’s amplitude and polarization angle and its times of occurrence in relation to the planet’s atmospheric data,we suggest that this20-s signal may be relevant to wind and temperature variations on Mars.Furthermore,we study the possible influence of this 20-s signal on the noise autocorrelation and find that the stacked autocorrelograms can be quite different when the 20-s signal is present.展开更多
High-speed rotor rotation under the low-density condition creates a special low-Reynolds compressible flow around the rotor blade airfoil where the compressibility effect on the laminar separated shear layer occurs. H...High-speed rotor rotation under the low-density condition creates a special low-Reynolds compressible flow around the rotor blade airfoil where the compressibility effect on the laminar separated shear layer occurs. However, the compressibility effect and shock wave generation associated with the increase in the Mach number (M) and the trend change due to their interference have not been clarified. The purpose is to clear the compressibility effect and its impact of shock wave generation on the flow field and aerodynamics. Therefore, we perform a two-dimensional unsteady calculation by Computational fluid dynamics (CFD) analysis using the CLF5605 airfoil used in the Mars helicopter Ingenuity, which succeeded in its first flight on Mars. The calculation conditions are set to the Reynolds number (Re) at 75% rotor span in hovering (Re = 15,400), and the Mach number was varied from incompressible (M = 0.2) to transonic (M = 1.2). The compressible fluid dynamics solver FaSTAR developed by the Japan aerospace exploration agency (JAXA) is used, and calculations are performed under multiple conditions in which the Mach number and angle of attack (α) are swept. The results show that a flow field is similar to that in the Earth’s atmosphere above M = 1.0, such as bow shock at the leading edge, whereas multiple λ-type shock waves are observed over the separated shear layer above α = 3° at M = 0.80. However, no significant difference is found in the C<sub>p</sub> distribution around the airfoil between M = 0.6 and M = 0.8. From the results, it is found that multiple λ-type shock waves have no significant effect on the airfoil surface pressure distribution, the separated shear layer effect is dominant in the surface pressure change and aerodynamic characteristics.展开更多
基金support from the Indian Institute of Technology Bombay (IITB) for providing the necessary facility and IITB seed grant.
文摘The cryosphere component provides the most reliable and insightful indications of any planet’s climate dynamics.Using data from the Compact Reconnaissance Imaging Spectrometer for Mars(CRISM),we develop a novel approach to determining the broadband Visible and Near Infrared(VNIR)albedo of the Martian surface.This study focuses on albedo changes in the McMurdo crater,part of Mars’s south polar layer deposits.We compare seasonal and interannual variations of the McMurdo surface albedo before,during,and after the Global Dust Storm(GDS)of Martian Year(MY)34.As the seasons progressed from spring to summer,the mean albedo in MY 32 and 34 plunged by over 40%,by about 35%in MY 33,and by slightly more than 30%in MY 35.Compared interannually,however,mean albedo values within both seasons(spring and summer)exhibited no significant differences in those same years.Notably,interannual albedo difference maps reveal albedo variation of more than±0.3 in certain regions of the crater.Considering only snow-covered pixels,interannual albedo differences suggest that Mars dust had a pervasive impact on Mars’s cryosphere.Variations in maximum and minimum albedo values as high as 0.5 were observed,depending upon differences in the dust levels in Martian snow/ice.The maximum and the minimum snow albedo values were lowest in MY 34,indicating the effect of the intense dust storm event that year.The average snow albedo decreased from 0.45 in MY 32 to 0.40 in MY 33 and to 0.33 in MY 34,and then rose back to 0.40 in MY 35.This trajectory suggests a temporary deposition of dust,partially reversed after the GDS by self-cleaning mechanisms(local aeolian process and CO_(2)sublimation/deposition cycle).
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB 41000000).
文摘The InSight(Interior Exploration using Seismic Investigations,Geodesy,and Heat Transport)mission has recorded continuous ambient noise signals with many spectral peaks since its landing in 2018.The majority of these peaks are modes produced by instrumental vibrations and are associated with environmental factors,such as temperature and wind energy fluctuations.Understanding how these modes react under various conditions is crucial because it aids in identifying their origins.In this study,we analyzed the three-component spectra of InSight recordings from sols 184–738 and obtained the horizontal-to-vertical spectral ratio(HVSR,also known as H/V)curves for different time intervals.The primary modes,such as those at 3.3 and 4.1 Hz,exhibited different behaviors,suggesting diverse origins.Some modes were sensitive to low temperature and some were sensitive to high temperature.Additionally,we investigated the influence of wind and temperature on the H/V curve.The peak frequency was mainly affected by temperature,whereas the H/V value was not associated with the temperature or wind only.Characterizing these modes and elucidating their origins are significant for processing signals from InSight and can provide valuable guidance for designing future planetary seismometers.
基金supported financially by the Special Basic Research Program of China(Grant No.2008FY110200)partially by Open Programme of State Key Laboratory(No.SKLFSE201009)
文摘In high mountainous areas, the development and distribution of alpine permafrost is greatly affected by macro- and mi- cro-topographic factors. The effects of latitude, altitude, slope, and aspect on the distribution of permafrost were studied to under- stand the dislribution patterns of permafrost in Wenquan on the Qinghai-Tibet Plateau. Cluster and correlation analysis were per- formed based on 30 m Global Digital Elevation Model （GDEM） data and field data obtained using geophysical exploration and borehole drilling methods. A Multivariate Adaptive Regression Spline model （MARS） was developed to simulate permafrost spa- tial distribution over the studied area. A validation was followed by comparing to 201 geophysical exploration sites, as well as by comparing to two other models, i.e., a binary logistic regression model and the Mean Annual Ground Temperature model （IVlAGT）. The MARS model provides a better simulation than the other two models. Besides the control effect of elevation on permafrost distribution, the MARS model also takes into account the impact of direct solar radiation on permafrost distribution.
基金supported by the National Key Research and Development Program (2022YFF0503200)the National Natural Science Foundation of China (42274114)the Key Program of the Institute of Geology and Geophysics, Chinese Academy of Sciences (IGGCAS-202102)
文摘The principal moments of inertia(PMIs)with the principal axes are usually taken as the dynamic figure parameters of Mars;they can be deduced from satellite-observed degree-two gravitational potentials in recent global gravity models and from the dynamic ellipticities resulting from precession observations.These PMIs are natural and significant for the geodetic,geophysical,and geodynamic problems of Mars,which are functions of internal density distributions.In this study,a closed and concise formula for determining the PMIs of the entire planet and its core was developed based on the second invariants of gravity and a multipole expansion.We deduced the polar oblateness J^(2)and the equatorial ellipticity J_(22)of Mars to be 1.9566×10^(−3)and 6.3106×10^(−5),respectively.The preferred principal moments of inertia of Mars are A=2.66589×1036 kg·m^(2),B=2.66775×10^(36)kg·m^(2),and C=2.68125×10^(36)kg·m^(2).These values indicate that Mar is slightly triaxial.The equatorial principal moment of inertia of the Martian core is 1.46008×10^(35)kg·m^(2),accounting for~5.47%of the planet’s PMI;this result is critical for investigating the density and size of the core of Mars,and the planet’s free core nutation.
基金supported by the NSFC(Grant Nos 42130204 and 42188101)the Strategic Priority Program of the Chinese Academy of Sciences(Grant No.XDB41000000)the support of the Tencent Foundation.
文摘The Mars Orbiter MAGnetometer(MOMAG)is a scientific instrument onboard the orbiter of China’s first mission for Mars—Tianwen-1.Since November 13,2021,it has been recording magnetic field data from the solar wind to the magnetic pile-up region surrounding Mars.Here we present its in-flight performance and first science results,based on its first one and one-half months’data.Comparing these early MOMAG observations to the magnetic field data in the solar wind from NASA’s Mars Atmosphere and Volatile EvolutioN(MAVEN)mission,we report that the MOMAG magnetic field data are at the same level in magnitude,and describe the same magnetic structures with similar variations in three components.We recognize 158 clear bow shock(BS)crossings in these MOMAG data;their locations match well statistically with the modeled average BS.We also identify and compare five pairs of datasets collected when Tianwen-1’s orbiter and the MAVEN probe made simultaneous BS crossings.These BS crossings confirm the global shape of modeled BS,as well as the south-north asymmetry of the Martian BS.Two cases presented in this paper suggest that the BS is probably more dynamic at flank than near the nose.So far,MOMAG performs well,and provides accurate magnetic field vectors.MOMAG is continuously scanning the magnetic field surrounding Mars.Data from MOMAG’s measurements complement data from MAVEN and will undoubt edly advance our understanding of the plasma environment of Mars.
基金supported by the National Natural Science Foundation of China(Grant No.42241143)the pre-research projects on Civil Aerospace Technologies(No.D020104)funded by the China National Space Administration.
文摘The pitch angle distributions of ions and electrons can be affected by various processes;thus,they can serve as an important indicator of the physical mechanisms driving the dynamics of space plasmas.From observations from the Mars Ion and Neutral Particle Analyzer onboard the Tianwen-1 orbiter,we calculated the pitch angle distributions of protons in the Martian induced magnetosphere by using information from the magnetohydrodynamically simulated magnetic field,and we statistically analyzed the spatial occurrence pattern of different types of pitch angle distributions.Even though no symmetrical features were seen in the dataset,we found the dominance of the field-aligned distribution type over the energy range from 188 to 6232 eV.Maps of the occurrence rate showed the preferential presence of a trapped-like distribution at the lower altitudes of the surveyed nightside region.Although our results are more or less restricted by the adopted magnetic field,they indicate the complexity of the near-Mars proton pitch angle distributions and infer the possibility of wave–particle interactions in the Martian induced magnetosphere.
文摘This review article aims to gather differences and similarities between planet Mars and planet Earth to determine the necessities for the proper growth and development of the neonatal brain. Factors such as Environmental, Nutritional, Social, Stress, and Education are juxtaposed to understand the difference between pediatric neurodevelopment on both planets. The variation between each factor was analyzed to determine how significant the impact is on neurodevelopment for children. The factors to be discussed were generated based on extensive research on what is most important for proper early neurodevelopment. The five factors are the main categories branched out into subcategories to delve into more detail regarding neurodevelopment. Factors may vary based on the location on each planet, but the best average was cultivated to create a fair evaluation of the differences. Although each factor influences a different part of the brain, each factor (Environmental, Nutritional, Social, Stress, and Education) is equally vital for development anatomy and physiology of the brain.
基金supported by B-type Strategic Priority Program of the Chinese Academy of Sciences,Grant XDB41000000National Natural Science Foundation of China 42241117.
文摘Seismometers of the InSight probe(Interior Exploration using Seismic Investigation,Geodesy and Heat Transport)currently operating on Mars have recorded not only seismic events but also high-frequency non-seismic periodic signals that appear to have been induced by variations in the Martian environment and the hardware.Here,we report an observation of a long-period signal with a dominant period of~20 s from Martian solar days(Sol)800 to Sol 1,000.This 20-s signal is detected mostly at quiet nighttime—from22:00 to 04:00 LMST(Local Mean Solar Time)—at the InSight landing site.The measurement of the particle motion suggests that this linearly polarized signal focuses on the horizontal plane with an angle of~30°from the north.By examining the temporal variation of the signal’s amplitude and polarization angle and its times of occurrence in relation to the planet’s atmospheric data,we suggest that this20-s signal may be relevant to wind and temperature variations on Mars.Furthermore,we study the possible influence of this 20-s signal on the noise autocorrelation and find that the stacked autocorrelograms can be quite different when the 20-s signal is present.
文摘High-speed rotor rotation under the low-density condition creates a special low-Reynolds compressible flow around the rotor blade airfoil where the compressibility effect on the laminar separated shear layer occurs. However, the compressibility effect and shock wave generation associated with the increase in the Mach number (M) and the trend change due to their interference have not been clarified. The purpose is to clear the compressibility effect and its impact of shock wave generation on the flow field and aerodynamics. Therefore, we perform a two-dimensional unsteady calculation by Computational fluid dynamics (CFD) analysis using the CLF5605 airfoil used in the Mars helicopter Ingenuity, which succeeded in its first flight on Mars. The calculation conditions are set to the Reynolds number (Re) at 75% rotor span in hovering (Re = 15,400), and the Mach number was varied from incompressible (M = 0.2) to transonic (M = 1.2). The compressible fluid dynamics solver FaSTAR developed by the Japan aerospace exploration agency (JAXA) is used, and calculations are performed under multiple conditions in which the Mach number and angle of attack (α) are swept. The results show that a flow field is similar to that in the Earth’s atmosphere above M = 1.0, such as bow shock at the leading edge, whereas multiple λ-type shock waves are observed over the separated shear layer above α = 3° at M = 0.80. However, no significant difference is found in the C<sub>p</sub> distribution around the airfoil between M = 0.6 and M = 0.8. From the results, it is found that multiple λ-type shock waves have no significant effect on the airfoil surface pressure distribution, the separated shear layer effect is dominant in the surface pressure change and aerodynamic characteristics.
