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火星电离层探测 总被引:1,自引:1,他引:1
火星已经成为深空探测的重要目标之一, 登陆火星并在火星生存是人类探测火星的终极目标, 因此电离层是必须了解的火星电磁环境. 火星电离层探测包括直接探测和间接探测. 直接探测精度高, 有较高的空间分辨率, 但是观测时间短, 无法提供长期稳定的探测结果. 对火星电离层的间接探测结果主要来自无线电掩星探测和顶部雷达探测. 无线电掩星探测可实现对火星电离层整个电子密度剖面的长期稳定探测, 但其空间水平分辨率较低, 且可探测的电离层太阳天顶角范围受到地球与火星轨道的限制. 顶部雷达探测对火星电离层的探测具有很高的时间分辨率和空间分辨率, 且同样可进行长期稳定探测, 为火星电离层研究提供了最新的支持. 通过对火星电离层探测的基本方法及典型观测结果的分析, 提出通过几种探测方法适当结合的方式, 同时对火星电离层进行观测, 能够大大推进对火星电离层的研究. 相似文献
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Sebastian E. Schroeder Andreas Kullmann Peter Preusse Fred Stroh Katja Weigel Manfred Ern Peter Knieling Friedhelm Olschewski Reinhold Spang Martin Riese 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009,43(12):1910-1917
The CRISTA-NF instrument is the airborne version of the CRISTA satellite infrared limb sounder. It has been successfully flown on the Geophysica research airplane during a test campaign in July 2005, during the SCOUT-O3 Tropical Aircraft Campaign in November/December 2005 and during the AMMA campaign in August 2006. Radiance calibrations of the airborne instrument are more complex compared to the satellite instrument because the vacuum shell of CRISTA-NF is confined by a ZnSe (zinc–selenide) window and the detectors can thermally drift during measurement flights. By comprehensive radiance calibrations with a blackbody source the window’s emissivity and transmissivity are determined and the dependence of the instrument sensitivity on the detector temperature is characterized. Taking these effects into account, the remaining radiance error of the calibration is smaller than 3%. 相似文献
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E. Nielsen H. Zou D. A. Gurnett D. L. Kirchner D. D. Morgan R. Huff R. Orosei A. Safaeinili J. J. Plaut G. Picardi 《Space Science Reviews》2006,126(1-4):373-388
The Martian ionosphere has for the first time been probed by a low frequency topside radio wave sounder experiment (MARSIS)
(Gurnett et al., 2005). The density profiles in the Martian ionosphere have for the first time been observed for solar zenith angles less
than 48 degrees. The sounder spectrograms typically have a single trace of echoes, which are controlled by reflections from
the ionosphere in the direction of nadir. With the local density at the spacecraft derived from the sounder measurements and
using the lamination technique the spectrograms are inverted to electron density profiles. The measurements yield electron
density profiles from the sub-solar region to past the terminator. The maximum density varies in time with the solar rotation
period, indicating control of the densities by solar ionizing radiation. Electron density increases associated with solar
flares were observed. The maximum electron density varies with solar zenith angle as predicted by theory. The altitude profile
of electron densities between the maximum density and about 170m altitude is well approximated by a classic Chapman layer.
The neutral scale height is close to 10 to 13 km. At altitudes above 180 km the densities deviate from and are larger than
inferred by the Chapman layer. At altitudes above the exobase the density decrease was approximated by an exponential function
with scale heights between 24 and 65 km. The densities in the top side ionosphere above the exobase tends to be larger than
the densities extrapolated from the Chapman layer fitted to the measurements at lower altitudes, implying more efficient upward
diffusion above the collision dominated photo equilibrium region. 相似文献
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D. Bilitza 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
The International Reference Ionosphere (IRI) 2007 provides two new options for the topside electron density profile: (a) a correction of the IRI-2001 model, and (b) the NeQuick topside formula. We use the large volume of Alouette 1, 2 and ISIS 1, 2 topside sounder data to evaluate these two new options with special emphasis on the uppermost topside where IRI-2001 showed the largest discrepancies. We will also study the accurate representation of profiles in the equatorial anomaly region where the profile function has to accommodate two latitudinal maxima (crests) at lower altitudes but only a single maximum (at the equator) higher up. In addition to IRI-2001 and the two new IRI-2007 options we also include the Intercosmos-based topside model of Triskova, Truhlik, and Smilauer [Triskova, L., Truhlik, V., Smilauer, J. An empirical topside electron density model for calculation of absolute ion densities in IRI. Adv. Space Res. 37 (5), 928–934, 2006] (TTS model) in our analysis. We find that overall IRI-2007-NeQ gives the best results but IRI-2007-corrected provides a more realistic representation of the altitudinal–latitudinal structure in the equatorial anomaly region. The applicability of the TTS model is limited by the fact that it is not normalized to the F2 peak density and height. 相似文献
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