Interactions between trade wind shallow cumuli and their environment

浅层积云是地球上最常见的云类型；它们在热带信风中无处不在，它们的行为对我们了解大气至关重要，但我们对它们的了解仍然很少。这些低空的小而浅的对流云在调节其环境的热力学和动力学方面起着重要作用；通过凝结使云层变暖，将水汽输送到上面的逆温层，并通过云滴的蒸发和降水使逆温层和亚云层降温（Zhu and Bretherton 2004, Neggers et al. 2007）。此外，这些云发挥冷却辐射效应，反射短波辐射。浅积云行为的一个特别不确定的方面是它们与气候变化和气溶胶扰动的关系和反应。浅层对流与对流层的相互作用对气候敏感性有很大影响，它们的反馈是模式间气候敏感性差异的主要原因（Sherwood et al. 2014）。以前的研究表明，云丰度和降水等量对气溶胶增加的响应存在争议（Xue et al. 2008, Lonitz et al. 2015）。这些云的另一个有趣的特点是，尽管它们的个体尺寸很小，而且取决于当地的条件，它们能够产生中尺度的环流，从而形成有组织的大型云团。该组织的变化会对云量产生很大的影响（Vogel等人，2016），鉴于这些云的无处不在的性质及其对环境的影响，这一点非常重要。

The shallow cumulus cloud is the most prevalent cloud type on Earth; ubiquitous in the trade winds of the Tropics, their behaviour is critical to our understanding of the atmosphere, and yet is still poorly understood. These small, shallow convective clouds low in the atmosphere play an important role in regulating the thermodynamics and dynamics of their environment; warming the cloud layer through condensation, transporting moisture to the inversion layer above, and cooling of both the inversion, and the sub-cloud layer, through the evaporation of cloud droplets and precipitation (Zhu and Bretherton 2004, Neggers et al. 2007). Additionally, these clouds exert a cooling radiative effect, reflecting shortwave radiation. One particularly uncertain aspect of the behaviour of shallow cumuli is their relationship and response to a changing climate, and aerosol perturbations. The interactions of shallow convection with the troposphere have large implications for climate sensitivity, and their feedbacks are responsible for much of the spread in climate sensitivity between models (Sherwood et al. 2014). Previous works have shown contesting responses of quantities such as cloud abundance and precipitation to increases in aerosol (Xue et al. 2008, Lonitz et al. 2015). Another interesting feature of these clouds is that, despite their small individual size, and depending on local conditions, they are capable of producing mesoscale circulations which result in large organised patterns and clusters of clouds. Changes in this organisation can have large impacts on cloud amount (Vogel et al., 2016), which, given the ubiquitous nature of these clouds and their effects on their environment, is highly significant.