I have this doubt. With all the crazyness about being booted from Adsense because a fly or whatever, I wonder if I would have to inform Adsense that my peaks in traffic and earnings are expected due a branding campaing I'm starting. I guess they can't complain about the traffic quality since I'm using, guess what? Adwords :) But I wonder if they would be suspicious about my site being "suddenly popular". What do you think, paranoid besides?
I'm sure that adsense look at all aspects of the stats available to them.
If you are starting a new campaign or your site is listed somewhere and you suddenly get a surge of traffic then adsense will see the number of page impressions rise. They will then see a rise in clicks (hopefully :) ). Provided there is nothing suspicious about the clicks themselves they would assume that you are promoting your website sucessfully. If you get a sudden ctr of 100% because of the new traffic that would ring alarm bells, but if all of the stats are within sensible proportions to each other, but with bigger numbers then nothing to worry about.
Adsense is aware that we all get peaks and troughs is visitor numbers.