Variations in temperature induced by forced convection on the surface of a LiNbO3 melt during crystal growth have been studied. Temperature measurements on the melt surface of single crystals growing (circle divide 50mm) at rotation rates of 15-40 rpm on an RF-heated Czochralski puller has revealed that the melt surface continuously alternates between a steady and unsteady state of flow. This was attributed to the intermittently turbulent flow mode at intermediate rotation rates. The fluctuation period is thought to depend on the thickness of its boundary layer. The boundary layer varies in thickness due to the melt flow, which stops as the interface moves toward the crystal and resumes once the interface reverts to its former position. By contrast, at above 60 rpm, the melt surface temperature drops without fluctuation, indicating that turbulent flow is dominant at faster rotation rates. (C) 2004 Elsevier B.V. All rights reserved.