This paper computed the newest impact solutions of the potentially dangerous asteroid (99942) Apophis based on 4,138 optical observations from March 15.10789 UTC (Universal Time Coordinated), 2004 to February 28.0...This paper computed the newest impact solutions of the potentially dangerous asteroid (99942) Apophis based on 4,138 optical observations from March 15.10789 UTC (Universal Time Coordinated), 2004 to February 28.089569 UTC, 2014 and 20 radar observations from January 27, 2005 through March 15, 2013, as of June 20, 2014. Using the freely available the OrbFit software Package, this paper followed its orbit forward in the searching for close approaches with the Earth and possible impacts up to year 2116. With the different A2 non-gravitational parameter in the motion of the asteroid (99942) Apophis, this paper computed possible impact solutions using the JPL DE405 (Jet Propulsion Laboratory Development Ephemeris) and 25 additional massive perturbed asteroids. Additionally, this paper used weighing and selection methods adopted in the OrbFit software as prepared by the NEODyS (Near Earth Objects--Dynamical Side) Team. Moreover, this paper used method of computing the orbit of Apophis taking into account star catalog debiasing and an error model with assumed astrometric errors RMS (root mean square), deduced from the observational material of the given observatories. JPL's Sentry and NEODyS's CLOMMON2, two automatic monitoring systems routinely scanning for possible impacts in the next hundred years. Only for several dangerous asteroids presented results are computed with the non-gravitational parameters. This paper detected possible impacts of the asteroid (99942) Apophis only with the non-gravitational parameter, A2 〉 0. It was appeared that impacts in 2068, 2087, 2105 and in 2111 were possible only when Apophis rotated in prograde direction.展开更多
The United Nations 2030 Agenda for Sustainable Development provides an important framework for economic,social,and environmental action.A comprehensive indicator system to aid in the systematic implementation and moni...The United Nations 2030 Agenda for Sustainable Development provides an important framework for economic,social,and environmental action.A comprehensive indicator system to aid in the systematic implementation and monitoring of progress toward the Sustainable Development Goals(SDGs)is unfortunately limited in many countries due to lack of data.The availability of a growing amount of multi-source data and rapid advancements in big data methods and infrastructure provide unique opportunities to mitigate these data shortages and develop innovative methodologies for comparatively monitoring SDGs.Big Earth Data,a special class of big data with spatial attributes,holds tremendous potential to facilitate science,technology,and innovation toward implementing SDGs around the world.Several programs and initiatives in China have invested in Big Earth Data infrastructure and capabilities,and have successfully carried out case studies to demonstrate their utility in sustainability science.This paper presents implementations of Big Earth Data in evaluating SDG indicators,including the development of new algorithms,indicator expansion(for SDG 11.4.1)and indicator extension(for SDG 11.3.1),introduction of a biodiversity risk index as a more effective analysis method for SDG 15.5.1,and several new high-quality data products,such as global net ecosystem productivity,high-resolution global mountain green cover index,and endangered species richness.These innovations are used to present a comprehensive analysis of SDGs 2,6,11,13,14,and 15 from 2010 to 2020 in China utilizing Big Earth Data,concluding that all six SDGs are on schedule to be achieved by 2030.展开更多
文摘This paper computed the newest impact solutions of the potentially dangerous asteroid (99942) Apophis based on 4,138 optical observations from March 15.10789 UTC (Universal Time Coordinated), 2004 to February 28.089569 UTC, 2014 and 20 radar observations from January 27, 2005 through March 15, 2013, as of June 20, 2014. Using the freely available the OrbFit software Package, this paper followed its orbit forward in the searching for close approaches with the Earth and possible impacts up to year 2116. With the different A2 non-gravitational parameter in the motion of the asteroid (99942) Apophis, this paper computed possible impact solutions using the JPL DE405 (Jet Propulsion Laboratory Development Ephemeris) and 25 additional massive perturbed asteroids. Additionally, this paper used weighing and selection methods adopted in the OrbFit software as prepared by the NEODyS (Near Earth Objects--Dynamical Side) Team. Moreover, this paper used method of computing the orbit of Apophis taking into account star catalog debiasing and an error model with assumed astrometric errors RMS (root mean square), deduced from the observational material of the given observatories. JPL's Sentry and NEODyS's CLOMMON2, two automatic monitoring systems routinely scanning for possible impacts in the next hundred years. Only for several dangerous asteroids presented results are computed with the non-gravitational parameters. This paper detected possible impacts of the asteroid (99942) Apophis only with the non-gravitational parameter, A2 〉 0. It was appeared that impacts in 2068, 2087, 2105 and in 2111 were possible only when Apophis rotated in prograde direction.
基金supported by the Big Earth Data Science Engineering Program of the Chinese Academy of Sciences Strategic Priority Research Program(XDA19090000 and XDA19030000)。
文摘The United Nations 2030 Agenda for Sustainable Development provides an important framework for economic,social,and environmental action.A comprehensive indicator system to aid in the systematic implementation and monitoring of progress toward the Sustainable Development Goals(SDGs)is unfortunately limited in many countries due to lack of data.The availability of a growing amount of multi-source data and rapid advancements in big data methods and infrastructure provide unique opportunities to mitigate these data shortages and develop innovative methodologies for comparatively monitoring SDGs.Big Earth Data,a special class of big data with spatial attributes,holds tremendous potential to facilitate science,technology,and innovation toward implementing SDGs around the world.Several programs and initiatives in China have invested in Big Earth Data infrastructure and capabilities,and have successfully carried out case studies to demonstrate their utility in sustainability science.This paper presents implementations of Big Earth Data in evaluating SDG indicators,including the development of new algorithms,indicator expansion(for SDG 11.4.1)and indicator extension(for SDG 11.3.1),introduction of a biodiversity risk index as a more effective analysis method for SDG 15.5.1,and several new high-quality data products,such as global net ecosystem productivity,high-resolution global mountain green cover index,and endangered species richness.These innovations are used to present a comprehensive analysis of SDGs 2,6,11,13,14,and 15 from 2010 to 2020 in China utilizing Big Earth Data,concluding that all six SDGs are on schedule to be achieved by 2030.