Nocturnal spatial variation of temperature, wind, and turbulence over microtopography is generally poorly understood. Low amplitude microtopography covers much of the Earth’s surface and, with very stable conditions, can produce significant spatial variations of temperature and turbulence. We examine such variations over gentle terrain that include two shallow gullies that feed into a small valley. The gullies are covered by a sub-network of seven flux stations that is embedded within a larger network that covers the valley. The measurements indicate that gullies of only 2–5-m depth and 100-m width can often lead to spatial variations of temperature of several kelvin or more. Such variations depend on ambient wind speed and direction and the near-surface stratification. We investigate the surprising importance of microscale lee turbulence occurring over the gentle microtopography with slopes of only 5%. Near-surface stratification unexpectedly tends to increase with surface elevation on the slopes. We examine the potential causes of this puzzling behaviour of the near-surface stratification.

微地形上温度、风和湍流的夜间空间变化通常知之甚少。低振幅微地形覆盖了地球表面的大部分，在非常稳定的条件下，可以产生显着的温度和湍流空间变化。我们检查了平缓地形上的这种变化，其中包括两个流入小山谷的浅沟。沟壑被一个由七个通量站组成的子网络覆盖，该子网络嵌入一个覆盖山谷的更大网络中。测量表明，只有 2-5 米深和 100 米宽的沟壑往往会导致几开尔文或更高温度的空间变化。这种变化取决于环境风速和风向以及近地表分层。我们调查了在坡度仅为 5% 的平缓微地形上发生的微尺度背风湍流的惊人重要性。近地表分层出乎意料地倾向于随着斜坡上的地表海拔而增加。我们研究了近地表分层的这种令人费解的行为的潜在原因。