This is the 2590th most frequent Chinese word.
蓝天
Blue sky.
The word "蓝天" here refers to the general idea of a blue, clear sky in a descriptive context.
蓝天上飘着几朵白云。
A few white clouds float in the blue sky.
Here, "蓝天" is portrayed as part of a visual scene contributing to the pleasantness of the environment.
今天的天气真好,蓝天白云让人心情愉快。
The weather today is really nice; the blue sky and white clouds uplift one's mood.
In this sentence, "蓝天" is used to describe the sky in the photograph, emphasizing its aesthetic appeal and clarity.