摘要
在考虑由扩散与中性风引起的动力学输运与有原子离子O+(4S)、O+(2D)与O+(2P)以及分子离子Q2、NO+和N2参加光化学反应的电离层-热层体系中,提出一个一维时变的电离层剖面数值模型.通过数值计算着重讨论了武昌地区F2层峰以下,尤其是E/F与F1/F2谷区的电离层形态与有关过程,得到如下结论:(1)对于原子离子,单一成份O+(4S)的光化学反应与输运过程,可以解释F1/F2浅谷的形成;有O+(2D)参与的光化学反应.最有利于形成F1/F2深谷;O+(2P)不利于谷的形成.对于分子离子,由中性风引起的输运,也有助于深谷的形成.(2)原子离子和分子离子的过渡高度,大约在180-190km,早晚略高.在传统的电子连续性方程中,线性复合系数的假设只适用于此界之上.(3)最宽的F1/F2谷大约出现于地方时11h,最深谷则在正午.E/F谷宽约为20-30km(低年)和25-45km(高年),早晚比中午约宽10-20km.(4)O2是形成E层与F1层的主要成分,其高度剖面呈双峰状;下部峰形成E层,上部峰与NO+一起构成P1层.
Taking account of the photo-chemical reactions and the transport processes induced by diffusion and neutral wind, a one-dimensional and time-dependent numerical model for the ionospheric profile is established, in which stable and metastable atomic ions [O+(4S), O+(2D) and O+(2P)]and molecular ions (O2, NO+ and N2) are involved. Based on the model, the ionospheric morphology and related processes at WUCHANG (30.5°N, 114.4°E) in the region below the F2 peak, especially. within the E/F and F1/F2 valleys, are discussed, and the main results are summarized as follows:(1) With respect to atomic ions, the chemical reactions and the transport process for O+(4S) only are responsible for a shallow F1/F2 valley; the O+(2D)Patticipated reactions are more favourable to form a deep one conversely, O+(2P), when present, is an unfavourable factor for ie valley formation. As for molecular ions, the transport induced by neutral wind is also beneficial for a deep valley. (2) The atomic-molecular ions transit level is located at about 180-190 km with a larger value for morning and evening hours only above which the linear assumption of the loss rate is valid in the traditional continuity epuation with respect to electrons.(3) The widest F1/F2 valley occurs at 11h (LT), and the deepest Due at local noon. The E/F valley width is generally about 20-30km for low solar activity and 25-45km for high one, and the morning and evening values are 10-20km larger. (4) O2 with a double-peak profile is the most important composition in for ining E and F, ledges. Its low peak forms E-layer, while the upper one, in combination with NO+ contribution, makes up F1-Layer.Good agreements are found between the simulated and the observational results as a whole. The present model exhibits great potentiality for the study of ionospheric profiles, such as its mathematical description, the ionogram inversion techniques. and also the morphological and related mechanical research for a particular geophysical event.
出处
《空间科学学报》
CAS
CSCD
北大核心
1994年第2期116-124,共9页
Chinese Journal of Space Science
基金
国家自然科学基金
关键词
电离层
谷区
动力输运过程
Ionospheric numerical simulation, E/F and F1/F2 valley, Dynamical transport, Photo-chemical process