Couple of possible variants. Since the model is in deep blue, a reddish brown or brownish gray base would look quite well. Key with bases is always to provide a complementary scene - you want the miniature to "pop" on that terrain, even if you're going with camouflage type pattern. A yellow base would provide contrast, but it would draw the eye to the base first. Since your model is quite dark, you'd also want to keep the base rather dark to not overwhelm it, so with either a Mars type terrain or a gray cliff-like terrain, you'd do well to wash them down with a darker brown wash.
I suggest a simple technique - if possible, gently separate that model from the base, then make two bases or so, each with their different terrain type, then go with the one that works the best for you. It is very important that you like that base enough to do your whole army that way.