I am pretty sure there is an atmospheric explanation for this strange phenomenon. I assume its construction site noise or the highway that gets distorted by different temperature layers in the air . Still it is a very eerie sound that occasionally occurs. It is also not the first time i heard it, however this time i had my phone with me and was able to record.
OF THE
TIMES
Comment: He might not be far off in his conclusion that these strange sounds may be atmospheric in nature. See: