大气模式动态测定的研究

利用12万组大气阻力资料，对DTM－1994模式进行改造，获得了一个新的大气模式，该模式的特点是：1．利用2阶周日峰效应，代替了原来模式中的复杂的周日效应表达式，减少了模式参数（少于50个），并使模式参数均具有明确的物理意义，2．分清了模式的主要参数和次要参数，在主要参数中，又分清了利用了阻力资料可以改进的参数和可能改不好的参数．3．与MSIS－1990和DTM－1994模式相比，其互差可以被接受，说明使用卫星阻力资料可以进行大气模式动态改正，不仅能测定大气总密度，并且能测定大气的分密度，4．与卫星轨道相比较，改进有显优于MSIS－1990模式，在120km轨道附近，改进模式密度比MSIS－1990模式大10％，同时我们在卫星陨落期预报中发现，MSIS－1990模式密度比实际大气密度小9％，这说明改进模式的密度与实际大气的密度基本接近。

On the Dynamic Determination of the Atmosphere Model

Based on the 120000 sets of drag data, we have obtained a new atmospheric model by improving the DTM-1994 model. The new model has the following characteristics: 1. The second order diurnal peak effect was used to replace the original complicated formula for the diurnal effect, which greatly reduces the mumbers of model paramenters(less than 50). Each new parameter has its definite physical meaning. 2. The primary and secondary model parameters were distinguished. Within.primary parameters, we forther clarigy which one is able to be improved by using drag data and which one may be not. 3. When the new model is compared with MSIS-1990 and DTM-1994 models, the systematic error is acceptable, indicsting that drag data from satellites can be used to carry out dynamic adjustment of the atmosphere model. It can determine not only the total atmosphere density, but also the densities of the atmospheric components. 4. When compared with the satellite orbits, there exists significant difference between improved model and current MSIS-1990 and DTM-1994. Around 120 km orbit, improved model density is greater than MSIS-1990 by 10%. Meanwhile, it was found that the MSIS-1990 model density was less than that of the observed atmosphere by 9% when predicton of the satellite orbit during its re-entry is done. This indicates that improved model density is close to the observed atmosphere.