Differential rotation of a stably stratified rotating fluid in a sphere when the spin-down forcing C_sd is strengthened. From left to right and top to bottom C_sd = 0, − 10^-6, − 10^-5, − 10^-4, − 10^-3, − 10^-2. Ekman and Prandtl numbers are E = 10^-7, Pr = 10^-4. All calculations have assumed β ≫ 1. Solid lines are for positive values, dotted for negative values. Numerical resolution used Nr = 200 Chebyshev polynomials radially and spherical harmonics up to order L = 250.