In this work we show that horizontal gradients of temperature and salinity with compensating effects on density can drive thermohaline intrusion in the fluid layer below. Specifically, different types of double diffusive convection generate differential vertical fluxes from the top boundary, which then sustain horizontal temperature and salinity gradients within the bulk. Interleaving layers develop in the bulk and slope downward towards the cold fresh side, which are of the diffusive type. New layers emerge near the bottom boundary and shift the existing layers upward due to the density difference induced by the divergence of the vertical fluxes through the top surface. Detailed analyses reveal that the present intrusion is consistent with those in the narrow fronts, and both layer thickness and current velocity follow the corresponding scaling laws. Such intrusion process provides an extra path to transfer heat and salinity horizontally towards the cold and fresh side, but transfer the density anomaly towards the warm and salty side. These findings extend the circumstances where thermohaline intrusions may be observed.

中文翻译：

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由上方的水平温度和盐度梯度引起的温盐交错

在这项工作中，我们表明温度和盐度的水平梯度以及对密度的补偿作用可以驱动温盐侵入下面的流体层。具体来说，不同类型的双扩散对流从顶部边界产生不同的垂直通量，然后维持体内的水平温度和盐度梯度。交错层大体发育，向冷鲜侧向下倾斜，属于扩散型。由于通过顶面的垂直通量的发散引起的密度差异，新层出现在底部边界附近并将现有层向上移动。详细分析表明，目前的入侵与狭窄前沿的入侵一致，并且层厚和电流速度都遵循相应的比例定律。这种侵入过程提供了一条额外的路径，将热量和盐分水平地转移到寒冷和新鲜的一侧，但将密度异常转移到温暖和咸的一侧。这些发现扩展了可能观察到温盐侵入的情况。