Determination of seasonal variations in the Martian neutral atmosphere   from observations of ionospheric peak height

doi:10.1029/2011JE003833

CORC > 北京大学 > 地球与空间科学学院

	Determination of seasonal variations in the Martian neutral atmosphere from observations of ionospheric peak height
	Zou, Hong ; Lillis, Robert J. ; Wang, Jin Song ; Nielsen, Erling
刊名	journal of geophysical research planets
	2011
关键词	MARS GLOBAL SURVEYOR ELECTRON-DENSITY PROFILES RADIO OCCULTATION MEASUREMENTS SOLAR-CYCLE VARIATION GENERAL-CIRCULATION MODEL CRUSTAL MAGNETIC-FIELDS INTERANNUAL VARIABILITY MIDDLE ATMOSPHERE GRAZING-INCIDENCE DUST STORMS
DOI	10.1029/2011JE003833
英文摘要	Radio occultation experiments allow us to measure electron and neutral densities in planetary atmospheres. Here we investigate such measurements from the Mars Global Surveyor Radio Science experiment in 2 consecutive Martian years (25 and 26). Using Chapman theory, we parameterize the ionospheric peak altitude in terms of the solar zenith angle, neutral scale height at the peak, neutral density at 20 km and the effective neutral scale height ((xi) over bar (n)) between 20 km and the peak, finding the latter to be the primary driver of peak altitude. From the occultation data, we observe that altitudes of peak electron density at high northern latitudes show a clear seasonal trend, increasing from northern summer (Ls = 90 degrees) to northern autumn (Ls = 180 degrees), driven by substantial increases in (xi) over bar (n), despite neutral densities at 20 km steadily decreasing as surface temperatures drop. We find these trends to be consistent with neutral density predictions from the LMD Mars Global Circulation Model at both 20 km and 130 km. The primary mechanism responsible for this increase in the 20-130 km effective neutral scale height (and hence temperature) is the southward drift in subsolar latitude as northern summer becomes autumn. This drives the seasonal evolution of the Martian interhemispheric Hadley circulation. The downward branch of this circulation leads to an increasing warming in the middle atmosphere at high north latitudes from the northern summer to the northern autumn, causing an increase in neutral scale height at and below the ionospheric peak and thus an increase in the ionospheric peak height.; Geochemistry & Geophysics; SCI(E); 0; ARTICLE; 116
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/155772]
专题	地球与空间科学学院
推荐引用方式 GB/T 7714	Zou, Hong,Lillis, Robert J.,Wang, Jin Song,et al. Determination of seasonal variations in the Martian neutral atmosphere from observations of ionospheric peak height[J]. journal of geophysical research planets,2011.
APA	Zou, Hong,Lillis, Robert J.,Wang, Jin Song,&Nielsen, Erling.(2011).Determination of seasonal variations in the Martian neutral atmosphere from observations of ionospheric peak height.journal of geophysical research planets.
MLA	Zou, Hong,et al."Determination of seasonal variations in the Martian neutral atmosphere from observations of ionospheric peak height".journal of geophysical research planets (2011).