回归年与恒星年是不同的两个概念。

Tropical year, and sidereal year are two different concepts.

在即回归年与恒星年是不同的两个概念。

Tropical year , and sidereal year are two different concepts .

尽管这样，实际上在天文上一回归年中有365.24219天——一回归年指的是由地球上观察，太阳在天空运行一整个圆周所用的时长。

It turns out, however, that there are 365.24219 days in an astronomical "tropical" year-defined as the time it takes the sun, as seen from Earth, to make one complete circuit of the sky.

以回归年和朔望月为基础，推导出阴、阳历日期换算公式。

Applying tropical year and lunation, the exchange formula of calendar and solar calendar could be derived.

然而，在更北的气候地带，由于实行季节性农耕，回归年变得更加关键。

In more northern climes, however, where seasonal agriculture was practised, the solar year became more crucial.