Whoah! That's awesome! He must really want to kill you!
But alas, it is not Alduin. I looked at that statue of Alduin from the CE. Alduin has a different head, wings, and is much spikier. His spikes are on his stomach, neck and shoulders. They are also tipped white and jagged. He is also much bigger. Alduin is also the last dragon to enter the world. People would know about dragons if Alduin was flying around.
The dragon we see is black though, and the largest dragon we have had footage of yet. He is probably a jill, or one of those special named dragon like Miralmur the one that preys on Whiterun. My guess is that dragon will reappear somewhere.

