The solar X-ray detector(SXD)onboard the Macao Science Satellite-1B was designed to monitor solar flare bursts and to study the solar activity in the 25th solar cycle.The SXD includes two parts:a soft X-ray detection ...The solar X-ray detector(SXD)onboard the Macao Science Satellite-1B was designed to monitor solar flare bursts and to study the solar activity in the 25th solar cycle.The SXD includes two parts:a soft X-ray detection unit and a hard X-ray detection unit.Both the soft X-ray detection unit and the hard X-ray detection unit include two collimators,two X-ray detectors(a silicon drift detector and a cadmium-zinc-telluride detector),and a processing circuit.Compared with similar instruments,the energy range of the SXD is wider(1–600 ke V)and the energy resolution is better(150 e V at 5.9 ke V,12%at 59.5 ke V,and 3%at 662 keV).展开更多
The Euler angle estimation is a calibration method for vector data measured by the magnetometer on a satellite.It is used to find the relative rotation between the coordinate system of the magnetometer and the satelli...The Euler angle estimation is a calibration method for vector data measured by the magnetometer on a satellite.It is used to find the relative rotation between the coordinate system of the magnetometer and the satellite(usually determined by Star Imagers).Before launch of the low-orbit,low-inclination Macao Science Satellite-1(known as MSS-1),we simulated the estimation of Euler angles by using the magnetic measurements of the in-orbit Swarm and China Seismo-Electromagnetic Satellite(noted as CSES),with various data combinations.In this study,11 data sets were designed to analyze the estimation results for the MSS-1 orbit by using a joint estimation method of the geomagnetic field model parameters and Euler angles.For the model results,we found that all the spatial power spectral lines showed behavior consistent with that of the CHAOS-7.8 model at low degrees(corresponding to large-scale magnetic signals).The spectra of models without global data coverage deviated much more(by a maximum of~10^(4) nT^(2))from those of the CHAOS-7.8 model at higher degrees.For models with global data coverage and with various data combinations,the spectral lines were distributed similarly.Moreover,the models with accordant power spectral distributions demonstrated different Euler angle estimations.As more vector data at higher latitudes were included,the estimated Euler angles varied monotonically in all three directions.The models with vector data in the same latitude range showed similar Euler angle results,regardless of whether the poleward scalar data were included.The largest value difference was found between the models using vector data within±40°latitudes and those using vector data within±60°latitudes,which reached to~28″.Therefore,we concluded that the inversion of the spherical harmonic Gauss coefficients in our tests was mainly affected by the spatial coverage range of the data,whereas the estimation of Euler angles largely depended on the latitude range where the vector data could be obtained.These results can be used for future in-flight data testing.We expect the estimation of Euler angles to improve as other methods are adopted.展开更多
Ground and space-based observations of the geomagnetic field are usually a superposition of different sources from the Earth’s core,lithosphere,ocean,ionosphere,and magnetosphere,and also from field-aligned currents ...Ground and space-based observations of the geomagnetic field are usually a superposition of different sources from the Earth’s core,lithosphere,ocean,ionosphere,and magnetosphere,and also from field-aligned currents coupling the ionosphere and magnetosphere—the meridional currents that connect the two hemispheres and the induced currents due to the variations of fields over time.The fluctuation of magnetic fields generated by these highly dynamic space currents greatly limits the accuracy of the geomagnetic models.In order to better accomplish the scientific objectives of Macao Science Satellite-1(MSS-1),and to improve existing geomagnetic field models,we present here for the first time a self-consistent coupling of solar wind,magnetosphere,and ionosphere,which represents the most developed numerical simulation method for space physics research so far,making it possible to quantify the contribution of different current systems to the total observed magnetic field(B).The results show that numerical simulation can capture main magnetic disturbance characteristics with significant precision.Partial ring current is a major contributor to the latitudinal magnetic perturbation near the equator.Magnetopause and magnetotail currents affect the radial magnetic perturbation around the mid-latitudes.Field-aligned and Pedersen currents produce significant longitudinal and latitudinal magnetic perturbations at high latitudes.展开更多
The Earth’s“lithosphere”is its outer shell,made up of the Earth’s crust and outermost mantle.The part of the Earth’s magnetic field that originates in the lithosphere consists of a superposition of magnetic anoma...The Earth’s“lithosphere”is its outer shell,made up of the Earth’s crust and outermost mantle.The part of the Earth’s magnetic field that originates in the lithosphere consists of a superposition of magnetic anomalies with a broad spectrum of sizes and intensities,which arise from geological and tectonic features.The lithospheric magnetic field is known from surface observations,and on larger scales from above-surface measurements.The increase in recent decades of satellites dedicated to measuring the Earth’s magnetic field has improved significantly our models of the Earth’s magnetic environment.Based on these increasing observations,a number of comprehensive field models have been constructed,some of which focus solely on the lithosphere,such as the MF model series.We present a map of lithospheric magnetic anomalies at 400 km altitude,based on a vertically integrated magnetization model.This height was chosen because it is the expected orbital altitude of the Macao Science Satellite-1(MSS-1)mission.The model presented herein indicates that the amplitude of the lithospheric anomalies at 400 km altitude is between-14.8 n T and 18.2 n T.This information is useful because it provides a reference for the lithospheric source of the Earth’s magnetic field that contributes to the magnetic measurements made from satellite instruments.The low inclination orbit of the MSS-1 mission will provide information that is sensitive to lateral variation within the lithosphere;these variations arise from plate tectonic features with longitudinal extent.In conclusion,the new MSS-1mission will provide valuable information in detecting compositional variations in the lithosphere,and in delineating large-scale geological structures.展开更多
An experiment is made to detect the land-cover change in the area located to the south of Aksu in the northern Taklimakan desert through analyses of satellite data pixel by pixel basis. The analyzed data are those obs...An experiment is made to detect the land-cover change in the area located to the south of Aksu in the northern Taklimakan desert through analyses of satellite data pixel by pixel basis. The analyzed data are those observed in the late summer and early autumn of 1973, 1977, 1993 and 1995. As a parameter of land-cover, SAVI (Soil Adjusted Vegetation Index) derived from the data of Landsat MSS and JERS-1 OPS (Optical Sensor) is used. The result indicates the increase of vegetation in the oasis areas, confluent area of the Yarkant and Kashgar Rivers and around reservoirs while little change occurs in the desert area. The 1973 satellite image shows the abundant flow in the Yarkant River while the river is almost dried up in the satellite images of later years. The trend of the decrease in the Hotan River flow is recognized although not so dramatic as that of the Yarkant River.展开更多
基金the China National Space Administration(CNSA)the Macao University of Science and Technology Foundation for their support of this paper。
文摘The solar X-ray detector(SXD)onboard the Macao Science Satellite-1B was designed to monitor solar flare bursts and to study the solar activity in the 25th solar cycle.The SXD includes two parts:a soft X-ray detection unit and a hard X-ray detection unit.Both the soft X-ray detection unit and the hard X-ray detection unit include two collimators,two X-ray detectors(a silicon drift detector and a cadmium-zinc-telluride detector),and a processing circuit.Compared with similar instruments,the energy range of the SXD is wider(1–600 ke V)and the energy resolution is better(150 e V at 5.9 ke V,12%at 59.5 ke V,and 3%at 662 keV).
基金funded by the Macao Foundation,the pre-research project of Civil Aerospace Technologies(Nos.D020308 and D020303)funded by the China National Space Administration,Macao Science and Technology Development Fund(FDCT+1 种基金No.0001/2019/A1)the opening fund of the State Key Laboratory of Lunar and Planetary Sciences(Macao University of Science and Technology,Macao FDCT No.119/2017/A3)。
文摘The Euler angle estimation is a calibration method for vector data measured by the magnetometer on a satellite.It is used to find the relative rotation between the coordinate system of the magnetometer and the satellite(usually determined by Star Imagers).Before launch of the low-orbit,low-inclination Macao Science Satellite-1(known as MSS-1),we simulated the estimation of Euler angles by using the magnetic measurements of the in-orbit Swarm and China Seismo-Electromagnetic Satellite(noted as CSES),with various data combinations.In this study,11 data sets were designed to analyze the estimation results for the MSS-1 orbit by using a joint estimation method of the geomagnetic field model parameters and Euler angles.For the model results,we found that all the spatial power spectral lines showed behavior consistent with that of the CHAOS-7.8 model at low degrees(corresponding to large-scale magnetic signals).The spectra of models without global data coverage deviated much more(by a maximum of~10^(4) nT^(2))from those of the CHAOS-7.8 model at higher degrees.For models with global data coverage and with various data combinations,the spectral lines were distributed similarly.Moreover,the models with accordant power spectral distributions demonstrated different Euler angle estimations.As more vector data at higher latitudes were included,the estimated Euler angles varied monotonically in all three directions.The models with vector data in the same latitude range showed similar Euler angle results,regardless of whether the poleward scalar data were included.The largest value difference was found between the models using vector data within±40°latitudes and those using vector data within±60°latitudes,which reached to~28″.Therefore,we concluded that the inversion of the spherical harmonic Gauss coefficients in our tests was mainly affected by the spatial coverage range of the data,whereas the estimation of Euler angles largely depended on the latitude range where the vector data could be obtained.These results can be used for future in-flight data testing.We expect the estimation of Euler angles to improve as other methods are adopted.
基金supported by the B-type Strategic Priority Program of the Chinese Academy of Sciences(Grant No.XDB41000000)Natural Science Foundation of Shanghai’s Science and Technology Innovation Action Plan(General Program:No.22ZR1472900)+4 种基金Study on the Environment and Dynamics of Earth’s Inner Magnetospheric Particles and the Needs of Space-based Exploration(Grant No.D-2022-09-13-001)Hong Kong-Macao-Taiwan Cooperation Funding of Shanghai Committee of Science and Technology(Grant No.19590761300)Shanghai 2022“Science and Technology Innovation Action Plan”Hong Kong,Macao and Taiwan Science and Technology Cooperation Project(Grant No.22590760900)Shanghai Postdoctoral Daily Funding(Grant No.K-2021-12-16001)。
文摘Ground and space-based observations of the geomagnetic field are usually a superposition of different sources from the Earth’s core,lithosphere,ocean,ionosphere,and magnetosphere,and also from field-aligned currents coupling the ionosphere and magnetosphere—the meridional currents that connect the two hemispheres and the induced currents due to the variations of fields over time.The fluctuation of magnetic fields generated by these highly dynamic space currents greatly limits the accuracy of the geomagnetic models.In order to better accomplish the scientific objectives of Macao Science Satellite-1(MSS-1),and to improve existing geomagnetic field models,we present here for the first time a self-consistent coupling of solar wind,magnetosphere,and ionosphere,which represents the most developed numerical simulation method for space physics research so far,making it possible to quantify the contribution of different current systems to the total observed magnetic field(B).The results show that numerical simulation can capture main magnetic disturbance characteristics with significant precision.Partial ring current is a major contributor to the latitudinal magnetic perturbation near the equator.Magnetopause and magnetotail currents affect the radial magnetic perturbation around the mid-latitudes.Field-aligned and Pedersen currents produce significant longitudinal and latitudinal magnetic perturbations at high latitudes.
基金supported by the Macao Foundationby the Preresearch Project on Civil Aerospace Technologies No.D020308/D020303 funded by China National Space Administration+1 种基金by the Macao Science and Technology Development Fund,grant No.0001/2019/A1PF Liu is funded by the Science and Technology Development Fund,Macao SAR(File No.0002/2019/APD)。
文摘The Earth’s“lithosphere”is its outer shell,made up of the Earth’s crust and outermost mantle.The part of the Earth’s magnetic field that originates in the lithosphere consists of a superposition of magnetic anomalies with a broad spectrum of sizes and intensities,which arise from geological and tectonic features.The lithospheric magnetic field is known from surface observations,and on larger scales from above-surface measurements.The increase in recent decades of satellites dedicated to measuring the Earth’s magnetic field has improved significantly our models of the Earth’s magnetic environment.Based on these increasing observations,a number of comprehensive field models have been constructed,some of which focus solely on the lithosphere,such as the MF model series.We present a map of lithospheric magnetic anomalies at 400 km altitude,based on a vertically integrated magnetization model.This height was chosen because it is the expected orbital altitude of the Macao Science Satellite-1(MSS-1)mission.The model presented herein indicates that the amplitude of the lithospheric anomalies at 400 km altitude is between-14.8 n T and 18.2 n T.This information is useful because it provides a reference for the lithospheric source of the Earth’s magnetic field that contributes to the magnetic measurements made from satellite instruments.The low inclination orbit of the MSS-1 mission will provide information that is sensitive to lateral variation within the lithosphere;these variations arise from plate tectonic features with longitudinal extent.In conclusion,the new MSS-1mission will provide valuable information in detecting compositional variations in the lithosphere,and in delineating large-scale geological structures.
文摘An experiment is made to detect the land-cover change in the area located to the south of Aksu in the northern Taklimakan desert through analyses of satellite data pixel by pixel basis. The analyzed data are those observed in the late summer and early autumn of 1973, 1977, 1993 and 1995. As a parameter of land-cover, SAVI (Soil Adjusted Vegetation Index) derived from the data of Landsat MSS and JERS-1 OPS (Optical Sensor) is used. The result indicates the increase of vegetation in the oasis areas, confluent area of the Yarkant and Kashgar Rivers and around reservoirs while little change occurs in the desert area. The 1973 satellite image shows the abundant flow in the Yarkant River while the river is almost dried up in the satellite images of later years. The trend of the decrease in the Hotan River flow is recognized although not so dramatic as that of the Yarkant River.
