动态中的晨昏线  

Cirdcle of culmination in motion

作　　者：郑晓娟[1] 

机构地区：[1]华北油田第一中学

出　　处：《陕西师范大学学报（自然科学版）》1995年第S1期175-176,共2页Journal of Shaanxi Normal University：Natural Science Edition

摘　　要：在多年教学实践基础上，发现掌握晨昏线的关键是明白晨昏线的位置，它随地球公转和太阳直射点的南北移动呈现有规律的变化，这种变化造成了地球上因时因地昼夜不等长现象．Through many years of teaching, found the most important thing to master the circle of culmination is to know that the position of the circle of culmination is changing regularly with the earth's revolution and the direct sunshine's moving between the northern hemisphere and southern hemisphere. The changes result in the different lengths of day and night on every part of the earth except the spring equinox and the autumnal equinox. On the basis and the method of counting the tengths of day and night is discussed.

关 键 词：晨昏线 地球公转 回归运动 昼夜长短 

分 类 号：I253.4[文学—中国文学]