To inform the reader that they are specifically talking about something else, another thing that could be informative
The connective here is "in the same way".
This connective can be rephrased in the following ways, and it would keep its meaning then:
Similarly,
Similar to this,
Not unlike this
etc.
We see here that the connective shows a comparison (this is the correct answer) - the two things are similar!
If you mean figurative language then
"air of night"