Burning fat is an all-body process, and you can't target where you lose weight from. Energy is delivered to the muscles via the bloodstream, NOT from being absorbed from surrounding fat stores. All the abdominal exercises in the world will not reduce fat stored there.
What you can do is to continue to reduce your overall body fat through a combination of cardio, all-body strength training and watching your intake, and some of it will naturally come off the belly.
Oh, and the abs are just one big muscle. Take a look at en.wikipedia.org/wiki/Rectus_abdominis_mus
. There's no such thing as "lower abs".