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2801.赤道电离层不规则对传播/导航系统的影响评估研究
[信息传输、软件和信息技术服务业,科学研究和技术服务业] [2014-09-02]
The main purpose of the study is to carry out a correlated study of global and seasonal scintillation morphology in the equatorial region using a coincident observation that occurred on 24 Mar 2000 between the irregularity structure observed by ROCSAT-1 and the scintillation experiment carried out at the Ascension Island. The two sets of data were studied separately first, and then compared correlatively for their causal relationship. The results show the reasonable scintillation level at coincident time to indicate a direct relationship between the irregularity structure and the scintillation in both temporal and amplitude variations. Second, since the ionospheric density irregularities are the source of ionospheric radiowave scintillation that affects space communication and navigation, in-depth investigation for the cause of ionospheric irregularities has been carried out. In conclusion, our analysis indicates that the seeding of deep atmospheric convection represented by OLR for the ionospheric irregularity occurrences has not happened as frequently as it was thought.
关键词:电离层闪烁;大气化学;大气科学;通信和广播系统;
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2802.远物由各向异性和非柯尔莫哥洛夫震荡产生的闪光
[科学研究和技术服务业] [2014-09-02]
Observations at AMOS and elsewhere suggest that turbulence is sometimes non-isotropic and non-Kolmogorov in nature. Such turbulence can produce different jitter, wavefront error, and scintillation than expected from isotropic Kolmogorov turbulence. These differences can impact the design of sensor systems that must see through this atypical turbulence. Quantitative definitions are provided for anisotropic turbulence and non-Kolmogorov turbulence. Using previously developed analyses and with extensive simulations for a plane wave, corresponding to light from a satellite or star, results are presented that parametrically show how scintillation differs from that of standard Kolmogorov turbulence, under a variety of conditions. Also included are conditions appropriate for observations of sources on Mauna Loa as seen at AMOS.
关键词:大气运动;闪烁;空间物体;各向异性;远距离(距离)
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2803.微重力下船员暴露在轻度低压缺氧环境中的运作数据
[科学研究和技术服务业] [2014-08-31]
No abstract available.
关键词:减压病;缺氧;微重力;大气压力;飞行后分析;脱氮
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2804.卫星遥感SST反演整幅的改进
[科学研究和技术服务业,信息传输、软件和信息技术服务业] [2014-08-31]
关键词:科学卫星;算法;红外图像;纬度;线性度;海洋表面
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2805.火星科学实验室的下降、着陆轨迹和大气重建
[科学研究和技术服务业] [2014-08-31]
On August 5th 2012, The Mars Science Laboratory entry vehicle successfully entered Mars atmosphere and landed the Curiosity rover on its surface. A Kalman filter approach has been implemented to reconstruct the entry, descent, and landing trajectory based on all available data. The data sources considered in the Kalman filtering approach include the inertial measurement unit accelerations and angular rates, the terrain descent sensor, the measured landing site, orbit determination solutions for the initial conditions, and a new set of instrumentation for planetary entry reconstruction consisting of forebody pressure sensors, known as the Mars Entry Atmospheric Data System. These pressure measurements are unique for planetary entry, descent, and landing reconstruction as they enable a reconstruction of the freestream atmospheric conditions without any prior assumptions being made on the vehicle aerodynamics. Moreover, the processing of these pressure measurements in the Kalman filter approach enables the identification of atmospheric winds, which has not been accomplished in past planetary entry reconstructions. This separation of atmosphere and aerodynamics allows for aerodynamic model reconciliation and uncertainty quantification, which directly impacts future missions. This paper describes the mathematical formulation of the Kalman filtering approach, a summary of data sources and preprocessing activities, and results of the reconstruction.
关键词:大气层;降落轨迹;着陆地点;火星大气层;空气动力特性
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2806.冷进化行星粉尘的产生和质量损失
[科学研究和技术服务业] [2014-08-31]
Following the red giant branch phase and the subsequent core He-burning phase, the low- to intermediate-mass stars (0.8<M/M solar mass <8) begin to ascend the asymptotic giant branch (AGB). Pulsations levitate material from the stellar surface and provide density enhancements and shocks, which can encourage dust formation and re-processing. The dust composition depends on the atmospheric chemistry (abundance of carbon relative to oxygen), which is altered by dredging up newly formed carbon to the surface of the star. I will briefly review the current status of models that include AGB mass loss and relate them to recent observations of AGB stars from the Surveying the Agents of Galaxy Evolution (SAGE) Spitzer surveys of the Small and Large Magellanic Clouds, including measures of the total dust input to the interstellar medium from AGB
关键词:星际物质;恒星质量;大气化学
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2807.最终报告:开发采用ARM的数据改进技术云的卫星遥感和辐射.1997年3月1日-2006年2月28日
[科学研究和技术服务业,铁路、船舶、航空航天和其他运输设备制造业] [2014-08-31]
During the period, March 1997 February 2006, the Principal Investigator and his research team co-authored 47 peer-reviewed papers and presented, at least, 138 papers at conferences, meetings, and workshops that were supported either in whole or in part by this agreement. We developed a state-of-the-art satellite cloud processing system that generates cloud properties over the Atmospheric Radiation (ARM) surface sites and surrounding domains in near-real time and outputs the results on the world wide web in image and digital formats. The algorithms used in this system to generate cloud properties were validated and improved by the research conducted under this agreement. The team supported, at least, 11 ARM-related or supported field experiments by providing near-real time satellite imagery, cloud products, model results, and interactive analyses for mission planning, execution, and post-experiment scientific analyses. Comparisons of cloud properties derived from satellite, aircraft, and surface measurements were used to evaluate uncertainties in the cloud properties. Multiple-angle satellite retrievals were used to determine the influence of cloud structural and microphysical properties on the exiting radiation field.
关键词:环境科学;大气辐射;遥感;卫星;表面温度
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2808.先进航天飞机上阶段的概念中大型液态氢罐的快速降温和填充测试
[科学研究和技术服务业] [2014-08-31]
Cryogenic upper stages in the Space Shuttle program were prohibited primarily due to a safety risk of a 'return to launch site' abort. An upper stage concept addressed this concern by proposing that the stage be launched empty and filled using shuttle external tank residuals after the atmospheric pressure could no longer sustain an explosion. However, only about 5 minutes was allowed for tank fill. Liquid hydrogen testing was conducted within a near-ambient environment using the multipurpose hydrogen test bed 638.5 ft3 (18m3) cylindrical tank with a spray bar mounted longitudinally inside. Although the tank was filled within 5 minutes, chilldown of the tank structure was incomplete, and excessive tank pressures occurred upon vent valve closure. Elevated tank wall temperatures below the liquid level were clearly characteristic of film boiling. The test results have substantial implications for on-orbit cryogen transfer since the formation of a vapor film would be much less inhibited due to the reduced gravity. However, the heavy tank walls could become an asset in normal gravity testing for on-orbit transfer, i.e., if film boiling in a nonflight weight tank can be inhibited in normal gravity, then analytical modeling anchored with the data could be applied to reduced gravity environments with increased confidence.
关键词:低温液体;流体管;液态氢;膜态沸腾;传热
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2809.大型火焰传播环境特性测试
[科学研究和技术服务业] [2014-08-31]
Under the Advanced Exploration Systems (AES) Spacecraft Fire Safety Demonstration Project (SFSDP), as a risk mitigation activity in support of the development of a large-scale fire demonstration experiment in microgravity, flame-spread tests were conducted in normal gravity on thin, cellulose-based fuels in a sealed chamber. The primary objective of the tests was to measure pressure rise in a chamber as sample material, burning direction (upward/downward), total heat release, heat release rate, and heat loss mechanisms were varied between tests. A Design of Experiments (DOE) method was imposed to produce an array of tests from a fixed set of constraints and a coupled response model was developed. Supplementary tests were run without experimental design to additionally vary select parameters such as initial chamber pressure. The starting chamber pressure for each test was set below atmospheric to prevent chamber overpressure. Bottom ignition, or upward propagating burns, produced rapid acceleratory turbulent flame spread. Pressure rise in the chamber increases as the amount of fuel burned increases mainly because of the larger amount of heat generation and, to a much smaller extent, due to the increase in gaseous number of moles. Top ignition, or downward propagating burns, produced a steady flame spread with a very small flat flame across the burning edge. Steady-state pressure is achieved during downward flame spread as the pressure rises and plateaus. This indicates that the heat generation by the flame matches the heat loss to surroundings during the longer, slower downward burns. One heat loss mechanism included mounting a heat exchanger directly above the burning sample in the path of the plume to act as a heat sink and more efficiently dissipate the heat due to the combustion event. This proved an effective means for chamber overpressure mitigation for those tests producing the most total heat release and thusly was determined to be a feasible mitigation strategy to incorporate into the microgravity experiment.
关键词:火焰传播;引力效应;燃烧;航空安全;燃烧速率
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2810.宇宙生成的放射性核素(~(10)Be)的大气输送和沉积:回顾与展望
[科学研究和技术服务业] [2014-08-31]
Cosmogenic radionuclides, such as ~(10)Be, are commonly used for reconstructing solar activity in the past. The interpretation of ~(10)Be records, most commonly obtained from polar ice cores, is complicated by the mixing of ~(10)Be in the atmosphere, its transport to polar regions and its deposition. Throughout the generations of ~(10)Be studies these complications have been mentioned but never investigated on a physical basis. This manuscript aims to summarize the recent efforts to study the atmospheric transport of ~(10)Be from its production to its deposition into the polar ice using three-dimensional physically based general circulation models (GCMs) of the atmosphere. These models represent our best understanding of the atmospheric processes up to date. The model studies indicate that the most important factor controlling the deposition response of ~(10)Be to production changes is the fact that a major part of it (~65) is produced in the stratosphere where its residence time is long and it undergoes strong mixing. Therefore, in an ideal archive the ~(10)Be concentrations will reflect the global mean production rate and hence changes in the solar activity. An explanation is offered for the partly different deposition responses of ~(10)Be snow concentrations to production changes obtained with two different GCMs.
关键词:大气传输;沉积;气候影响;铍-10