I will be petitioning my wife for divorce. I have had varied income over the past 3 years: $240k in 2010, $280k in 2011, $150k in 2012, and likely $400k in 2013. Will the courts utilize my reduced income in 2012 during alimony calculations?

They usually use your last W2 and all sources of income combined. If for some reason you don't feel that is an actual reflection of your financial picture you can present your case as to why it should waiver from the standard formula.