在“距地面60—800km高度范围的大气……处于电离状态,所以叫作电离层”(1993年高中《地理》上册,以下同)。对电离层范围的这一认识.就使其与“从中间层顶到500km高度的范围”的热层,完全区分开来。这是人们对“电离层”深入研究的新成果。 “电离层”与人们的生产和生活关系十分密切,广大的中学生对于“电离层能反射无线电波”已有初步了解,所以往往会提出与其相关的问题,为此,现将无线 In the “atmosphere from the ground 60-800km altitude ... ionized state, so called ionosphere” (1993 high school “geography”, the same below). This understanding of the extent of the ionosphere makes it completely distinguishable from the thermal layer “from the top of the middle layer to the 500 km height.” This is a new achievement of people's in-depth study of the “ionosphere.” The “ionosphere” has very close relations with people's production and life. The majority of middle school students have already got an initial understanding of the “ionospheric radio waves” and therefore often ask questions related to them. For this reason,