The observational absence of giant convection cells near the Sun’s outer surface is a long-standing conundrum for solar modelers. We herein propose an explanation. Rotation strongly influences the internal dynamics, leading to suppressed convective velocities, enhanced thermal-transport efficiency, and (most significantly) relatively smaller dominant length scales. We specifically predict a characteristic convection length scale of roughly 30-Mm throughout much of the convection zone, implying weak flow amplitudes at 100- to 200-Mm giant cells scales, representative of the total envelope depth. Our reasoning is such that Coriolis forces primarily balance pressure gradients (geostrophy). Background vortex stretching balances baroclinic torques. Both together balance nonlinear advection. Turbulent fluxes convey the excess part of the solar luminosity that radiative diffusion cannot. We show that these four relations determine estimates for the dominant length scales and dynamical amplitudes strictly in terms of known physical quantities. We predict that the dynamical Rossby number for convection is less than unity below the near-surface shear layer, indicating rotational constraint.

太阳外表面附近观测到的巨型对流单元的缺失对于太阳建模者来说是一个长期存在的难题。我们在此提出一个解释。旋转强烈影响内部动力学，导致对流速度受到抑制，热传输效率提高，以及（最显着的）相对较小的主导长度尺度。我们特别预测整个对流区的特征对流长度尺度约为 30 毫米，这意味着 100 至 200 毫米巨细胞尺度的弱流动幅度，代表总包络深度。我们的推理是，科里奥利力主要平衡压力梯度（地转）。背景涡旋拉伸平衡斜压扭矩。两者一起平衡非线性平流。湍流通量传递了辐射扩散无法传递的多余部分的太阳光度。我们表明，这四种关系严格地根据已知物理量确定了主要长度尺度和动态振幅的估计。我们预测对流的动力学罗斯贝数小于近地表剪切层下方的统一数，表明旋转约束。