A series of high‐resolution three‐dimensional simulations of the diurnal cycle of deep convection over land are performed using the new Met Office NERC cloud‐resolving model. This study features scattered convection. A memory function is defined to identify the effects of previous convection in modifying current convection. It is based on the probability of finding rain at time t₀ and at an earlier time t₀−Δt compared to the expected probability given no memory. The memory is examined as a function of the lag time Δt. It is strongest at gray‐zone scales of 4–10 km, there is a change of behavior for spatial scales between 10 and 15 km, and it is reduced substantially for spatial scales larger than 25 km. At gray‐zone scales, there is a first phase of the memory function which represents the persistence of convection and it is maintained for about an hour. There is a second phase which represents the suppression of convection in regions which were raining 1 to 3 hr previously, and subsequently a third phase which represents a secondary enhancement of precipitation. The second and third phases of the memory function develop earlier for weaker forcing. When thermodynamic fluctuations resulting from the previous day are allowed to influence the development of convection on the next day, there are fewer rainfall events with relatively large sizes, which are more intense, and thus decay and recover more slowly, in comparison to the simulations where feedback from previous days is removed. Further sensitivity experiments reveal that convective memory attributed to these thermodynamic fluctuations resides in the lower troposphere.

中文翻译：

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对流昼夜周期云解析模拟中的记忆性质

使用新的Met Office NERC云解析模型对陆地深对流的昼夜周期进行了一系列高分辨率的三维模拟。这项研究的特点是分散的对流。定义了记忆功能以识别先前对流在修改当前对流中的作用。它的时间是基于发现下雨的概率牛逼₀，并在一个较早的时间牛逼₀ -Δ牛逼相比没有给出内存预期的概率。存储器检查作为滞后时间的函数Δ吨。它在4-10 km的灰阶上最强，在10到15 km之间的空间尺度上会发生行为变化，而在大于25 km的空间尺度上会大大减小。在灰阶范围内，记忆功能的第一阶段代表对流的持续性，并维持约一个小时。有一个第二阶段表示对流，该区域在先前下雨1至3小时的区域中抑制了对流，随后出现了一个第三阶段，该阶段代表了降水的二次增强。记忆功能的第二阶段和第三阶段发展得较早，其强迫性较弱。如果允许前一天产生的热力学波动影响第二天对流的发展，那么相对较大的降雨事件就更少了，与移除前几天的反馈的模拟相比，它们的强度更高，因此衰减和恢复速度更慢。进一步的敏感性实验表明，归因于这些热力学波动的对流记忆存在于对流层下部。