Fennec - The Saharan Climate System

撒哈拉中部是地球上气候最极端的地区之一。在北部夏季的几个月里，一个由强烈阳光造成的大型低气压系统在马里北部、阿尔及利亚南部和毛里塔尼亚东部的一大片基本上无人居住的地区发展起来。40多度的高温是正常的，在被认为是地球上最深的大气层中，干燥空气通过6000米以上的大气层上升是司空见惯的。这一大片区域也是地球大气层中尘埃层最厚的地方。虽然撒哈拉中部非常偏远，但事实证明，它对世界的天气和气候至关重要。大型低压系统驱动西非季风，干燥、尘土飞扬的空气层与大西洋上空形成的热带气旋密切相关。同样，多尘的空气对大气层的加热方式也有很大的影响，这一过程人们知之甚少。不足为奇的是，我们用来预测天气和气候的模式，以及理解大气如何运行的关键工具，在处理撒哈拉中部地区时都存在问题。在撒哈拉沙漠，由于缺乏对大气和造成沙尘和极端天气的过程的测量，对气候系统如何工作的洞察、改进模型和因此的预测都受到了阻碍。在一个团队前往撒哈拉中部并进行这些测量之前，这种情况将一直存在。这项提案的一个关键部分就是做到这一点。我们想在撒哈拉中部精心挑选的两个地点的地表上安装一系列特殊仪器，这些仪器将监测一整年的风、温度、尘埃等。我们将在6月份的核心夏季月份为更短的时间段甚至更强烈的测量增加这一集合。我们还计划将一架安装在飞机上的仪器飞越地面阵列，飞越沙漠，这样我们就可以了解大气的结构以及它在一天中是如何变化的。为了了解沙尘暴是如何发生的，我们将在我们认为沙尘暴频繁发生的地方设立10个气象站。卫星在测量天气和气候方面发挥着至关重要的作用，在偏远地区尤其有用。来自卫星的最佳可用信息将有助于量化撒哈拉地区的天气和气候如何起作用。我们还希望改进卫星进行测量的方式。由于模型对于理解和预报天气是如此重要，我们将在这项工作中大量使用它们。我们想知道这些模型在撒哈拉沙漠地区的效果如何，以及可以做些什么来改进它们。我们尤其感兴趣的是，如果我们允许这些模型处理气候系统的一小部分，是否会更好地发挥作用，或者我们是否仍然可以通过忽略模型中的这些细节来代表撒哈拉沙漠的极端地区。

The central Sahara has one of the most extreme climates on Earth. During the northern summer months, a large low pressure system caused by intense sunshine develops over a huge, largely uninhabited expanse of northern Mali, southern Algeria and eastern Mauritania. Temperatures in the high 40s are normal and uplift of dry air through more than 6000m of the atmosphere is routine in what is thought to be the deepest such layer on the planet. This large zone is also where the thickest layer of dust anywhere in the Earth's atmosphere is to be found. Although the central Sahara is extremely remote, it turns out to be vitally important to the world's weather and climate. The large low pressure system drives the West African Monsoon and the dry, dusty air layers are closely related to the tropical cyclones which form over the Atlantic Ocean. Likewise, the dusty air has a strong influence on the way the atmosphere is heated, a process which is poorly understood. It is not surprising that the models we use to predict weather and climate and which are a crucial tool for understanding how the atmosphere works, all have problems in dealing with the central Sahara. Insights into how the climate system works, improving the models and therefore the predictions have all been held back in the case of the Sahara by a lack of measurements of the atmosphere and the processes that make dust and extreme weather. This will always be the case until a team goes to the central Sahara and makes these measurements. A key part of this proposal aims to do just that. We want to set up an array of special instruments, at the surface in two carefully chosen places in the central Sahara, which will monitor the winds, temperatures, dust and so on for an entire year. We will add to this collection for a shorter period of even more intense measurements during the core summer month of June. We plan also to fly a instruments attached to an aeroplane overhead the surface array and across the desert so that we can get an idea of the structure of the atmosphere and how it changes through the day. To find out how dust storms work, we will leave 10 weather stations at places where we think dust storms happen frequently. Satellites play an essential role in measuring weather and climate and are especially useful in remote places. The best available information from satellites will help to quantify how weather and climate works in the Sahara. We also expect to improve the way the satellites are able to make their measurements too. Because models are so important to understanding and predicting weather, we will make heavy use of them in this work. We want to know how well the models work over the Sahara and what can be done to improve them. We are especially interested in seeing whether the models work better if we allow them to deal with small parts of the climate system or whether we can still represent extreme places in the Sahara by ignoring these details in the models.