Chapman函数在实际模式大气中的数值积分计算

本文对Chapman阳光掠射函数[Ch(z_p,χ)]进行了数值积分,求得了其在实际模式大气中随观测高度z_p及天顶角χ的变化.计算并讨论了低热层高温度梯度、分子与湍流扩散、重力场及太阳活动对 Ch(z_p,χ)的影响.结果表明,在150 km以下,Ch(z_p,χ)与前人用等标高模式及等标高梯度模式的计算结果差别较大.其中高温度梯度的影响起主导作用.特别是太阳活动对Chapman函数影响较显著,高年与低年之间可变化10—40％(在大天顶角时),这有可能推动热层大气中辐射-光化学-动力学耦合关系的变化.

NUMERICAL CALCULATIONS OF CHAPMAN''''S FUNCTION IN A REALISTIC MODEL ATMOSPHERE

In present paper, the Chapman's grazing incidence function varing with heights of observational point and solar zenith angle is numerically calculated. The variation of Chapman's function in a realistic model atmosphere due to high temperature gradient, molecular and eddy diffusion transport, gravity field as well as solar activity is computed and discussed for the lower thermosphere. The results obtained indicate, in a realistic model atmosphere of the earth, especially at the thermospheric heights up to 150 km, the Chapman's function differs sufficiently from those calculated by previous authors using the constant scale height and constant scale height gradient models, and the influence of the high temperature gradient in the lower thermosphere plays a leading role among the other effects. The influences of solar activity on Chapman's function appear to be efficient at large solar zenith angles (in a range of 10-40% between high and low solar conditions). These results are of obvious benefit for the studies of solar radiation-photochemistry-dynamics processes in the thermosphere.