In the script for Thor, it's clear that the Bifröst 'landing sites' are branded with Asgardian "runes from the bifrost".
I've edited for brevity;
33 EXT. BIFROST LANDING SITE (JOTUNHEIM) - DAY 33
Snow flurries up when the Bifrost hits, as Thor and his band touch
down. RUNES from the Bifrost are imprinted on the ice around them.
111 EXT. BIFROST LANDING SITE (EARTH) - DAY 111
The Bifrost runes cover the desert sand around them.
The patterns appear to serve no specific purpose other than to make the landing site look more interesting.
As Visual Effects Supervisor Jake Morrison says;
They have nano-technology and anti-gravity but instead of making
futuristic spaceships they chose to make flying boats, because they
like boats; they’re Vikings!
The same principle (of covering their stuff with Norse and Celtic runes) clearly applies to all of their other technology. In the absence of any canon description, we can assume that they're simply decorative.
Out of universe, similar runes are found on the side of Mjolnir as well as in the designs for the forcefield, boats and other props seen in Thor and Thor 2. These are described by the Director of Thor 2 (Alan Taylor) as simply being
embedded or drawn from Norse sources and Celtic sources
and are intended to create an obvious visual link between Asgardian culture and ancient Earth culture. Again, there is no special meaning to the runes and designs which were evidently selected for their artistic appeal.