|Date||Nov 03, 2022|
We prove the global regularity of smooth solutions for a dissipative surface quasi-geostrophic equation with both velocity and dissipation logarithmically supercritical compared to the critical equation. By this, we mean that a symbol defined as a power of logarithm is added to both velocity and dissipation terms to penalize the equation's criticality. Our primary tool is the nonlinear maximum principle which provides transparent proofs of global regularity for nonlinear dissipative equations. In addition, we prove an exponential gradient estimate for the critical surface quasi-geostrophic equation which improves the previous double exponential bound "Kiselev et al. 2007".