Broadly corrosion and oxidisation are the same thing...

What you will be seeing are probably copper oxides (can be red or black)

http://en.wikipedia.org/wiki/Copper%28I%29_oxide (copper 1 oxide)
http://en.wikipedia.org/wiki/Copper%28II%29_oxide (copper 2 oxide)

and copper hydroxides (which are white to green)

http://en.wikipedia.org/wiki/Copper_hydroxide

Equation:

2Cu(s) + H2O(g) + CO2(g) ---> Cu(OH)2(s) + CuCO3(s)