On the analytic integrability of the 5-dimensional lorenz system for the gravity-wave activity

For the 5-dimensional Lorenz system dU/dT = -VW + bV Z, dV/dT = UW - bUZ, dW/dT = -UV, dX/dT = -Z, dZ/dT = bUV + X (with b ∈ ℝ a parameter), describing coupled Rosby and gravity waves, we prove that it has at most three functionally independent global analytic first integrals and exactly three functionally independent global analytic first integrals when b = 0. In this last case the system is completely integrable with an additional functionally independent first integral which is not globally analytic. © 2013 American Mathematical Society.