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Fennec - The Saharan Climate System

耳廓狐 - 撒哈拉气候系统

基本信息

批准号：
NE/G015929/1
负责人：
Helen Brindley
金额：
$ 36.55万
依托单位：
Imperial College London
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2010
资助国家：
英国
起止时间：
2010 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FG015929%2F1
关键词：
Fennec Saharan Climate System

项目摘要

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 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.

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，在马里北部、阿尔及利亚南部和毛里塔尼亚东部大片无人居住的地区，由强烈的阳光引起的大型低压系统形成。华氏40度以上的温度是正常的，干燥空气在6000米以上的大气层中上升是常规的，这被认为是地球上最深的大气层。这个大区域也是地球大气中最厚的尘埃层所在的地方。尽管撒哈拉中部非常偏远，但它对世界的天气和气候至关重要。大型低压系统驱动着西非季风，而干燥多尘的空气层与大西洋上空形成的热带气旋密切相关。同样，多尘的空气对大气加热的方式也有很大的影响，而人们对这一过程知之甚少。我们用来预测天气和气候的模型是了解大气如何运作的关键工具，在处理撒哈拉中部时都存在问题，这并不奇怪。对气候系统如何运作的深入了解、对模型的改进以及因此对撒哈拉沙漠的预测都受到了阻碍，因为缺乏对大气以及产生沙尘和极端天气的过程的测量。这种情况将一直持续下去，直到有一个团队前往撒哈拉中部进行这些测量。这项提议的一个关键部分就是要做到这一点。我们想在撒哈拉沙漠中部精心挑选的两个地方的地表设置一系列特殊的仪器，在一整年的时间里监测风、温度、尘埃等。我们将在夏季的核心月份6月期间，在更短的时间内增加更密集的测量。我们还计划在地面阵列上方的飞机上安装仪器，穿越沙漠，这样我们就可以了解大气的结构以及它在一天中的变化情况。为了了解沙尘暴是如何形成的，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运作。我们还希望改进卫星进行测量的方式。因为模型对于理解和预测天气非常重要，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上的效果如何，以及可以做些什么来改进它们。我们特别感兴趣的是，如果我们允许模型处理气候系统的一小部分，我们是否能更好地工作，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。