Theoretical Model for the Latitude Dependence of the Thermospheric Annual and Semiannual Variations H. G. M¾a Thermosp, here and Exosphere Branch, NASA Goddard Space Flight Center Greenbelt, Maryland 20771
Theoretical Model for the Latitude Dependence of the Thermospheric Annual and Semiannual Variations H. G. M¾a Thermosp, here and Exosphere Branch, NASA Goddard Space Flight Center Greenbelt, Maryland 20771
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DOI：
10.1029/ja077i034p06774
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发表时间：
1972-12
期刊：
影响因子：
--
通讯作者：
I. Volland
中科院分区：
文献类型：
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作者：
I. Volland
提出了热层年度和半年度变化的三维模型，其中以自洽形式考虑与全球环流相关的能量和扩散质量传输。结果表明，这些过程在热层动力学中发挥着重要作用，因此解释了许多温度和成分现象，例如（1）冬季半球低海拔地区的氦气和氧气膨胀，（2）年度成分中相对较大的温度变化（~26%），超过了从卫星阻力数据推断出的温度的3倍，对于处于扩散平衡的热层来说太大了，（3）7%的温度变化与纬度相关的半年成分中两极的外层温度与春分期间氧气和氦气的显着消耗有关，以及（4）与纬度相关的成分的总质量密度几乎与高度无关且相对较小的幅度，这是造成半年效应的纬度变化迄今为止未能从卫星阻力数据中观测到的事实的原因，并且与年度变化相比，半年效应的全球均匀成分似乎相对较强。
A three-dimensional model for the annual and semiannual variations of the thermosphere is presented in which the energy and diffusive mass transport associated with global circulation are considered in a self-consistent form. It is shown that these processes play a major role in thermosphere dynamics and thus account for a number of temperature and composition phenomena such as (1) the helium and oxygen bulges in the winter hemispheres at lower altitudes, (2) the relatively large temperature variations (∼26%) in the annual component, which exceed by a factor of 3 those temperatures inferred from the satellite drag data and would be much too large for a thermosphere in diffusive equilibrium, (3) the 7% variation of the exospheric temperature at the poles in the latitude dependent semiannual component associated there with a significant depletion of oxygen and helium during the equinox, and (4) the nearly height independent and relatively small amplitudes in the total mass density of the latitude dependent components that are responsible for the fact that the latitude variations of the semiannual effect have so far eluded observations from satellite drag data and that the globally uniform component of the semiannual effect appears to be relatively strong in comparison with the annual variations.