Fennec - The Saharan Climate System

耳廓狐 - 撒哈拉气候系统

• 批准号: NE/G017166/1
• 负责人: Douglas Parker
• 金额: $ 115.81万
• 依托单位: University of Leeds
• 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%2FG017166%2F1
• 关键词: Fennec; Saharan; Climate; System

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.

撒哈拉中部地区是地球上气候最极端的地区之一。在北部夏季，强烈的阳光造成的大型低压系统在马里北部、阿尔及利亚南部和毛里塔尼亚东部大片无人居住的地区形成。气温在 40 多度左右是正常现象，而干燥的空气上升到大气层 6000 多米以上的情况在被认为是地球上最深的大气层中是很常见的。这个大区域也是地球大气层中最厚的尘埃层所在。尽管撒哈拉中部极其偏远，但事实证明它对世界天气和气候至关重要。大型低压系统驱动西非季风，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，含尘的空气对大气的加热方式也有很大影响，但人们对这一过程知之甚少。毫不奇怪，我们用来预测天气和气候的模型以及了解大气如何运作的重要工具，在处理撒哈拉中部地区时都存在问题。就撒哈拉沙漠而言，由于缺乏对大气以及产生沙尘和极端天气的过程的测量，对气候系统如何运作的深入了解、模型的改进以及预测都受到了阻碍。在一个团队前往撒哈拉中部进行这些测量之前，情况将一直如此。该提案的一个关键部分旨在做到这一点。我们希望在撒哈拉中部精心挑选的两个地点安装一系列特殊仪器，用于监测一整年的风、温度、灰尘等。我们将在六月的核心夏季月份期间向此集合添加更短时间、更强烈的测量。我们还计划将连接在飞机上的仪器飞过地面阵列并穿越沙漠，以便我们能够了解大气的结构及其在一天中的变化。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重要作用，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的测量方式。由于模型对于理解和预测天气非常重要，因此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，以及可以采取哪些措施来改进它们。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，这些模型是否会工作得更好，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。

项目成果

Dust emission and transport mechanisms in the central Sahara: Fennec ground-based observations from Bordj Badji Mokhtar, June 2011

撒哈拉中部的粉尘排放和输送机制：Bordj Badji Mokhtar 的 Fennec 地面观测，2011 年 6 月

• DOI: http://dx.10.1002/jgrd.50534
• 发表时间: 2013
• 期刊: Atmospheres
• 作者: Allen C

The effect of orography and surface albedo on stratification in the summertime Saharan boundary layer: Dynamics and implications for dust transport

地形和地表反照率对夏季撒哈拉边界层分层的影响：粉尘输送的动力学和影响

• DOI: http://dx.10.1029/2011jd015965
• 发表时间: 2012
• 期刊: Atmospheres
• 作者: Birch C

The low-level jet dust emission mechanism in the central Sahara: Observations from Bordj-Badji Mokhtar during the June 2011 Fennec Intensive Observation Period Central Saharan LLJ dust emission

撒哈拉中部低空急流沙尘排放机制：2011 年 6 月 Fennec 密集观测期中撒哈拉低空急流沙尘排放期间 Bordj-Badji Mokhtar 的观测

• DOI: http://dx.10.1002/2013jd020594
• 发表时间: 2014
• 期刊: Atmospheres
• 作者: Allen C

An automated dust detection using SEVIRI: A multiyear climatology of summertime dustiness in the central and western Sahara

使用 SEVIRI 进行自动灰尘检测：撒哈拉中部和西部夏季灰尘的多年气候学

• DOI: http://dx.10.1029/2011jd016845
• 发表时间: 2012
• 期刊: Atmospheres
• 作者: Ashpole I

The Harmattan over West Africa: nocturnal structure and frontogenesis

西非上空的哈马坦：夜间结构和锋生

• DOI: http://dx.10.1002/qj.2036
• 发表时间: 2012
• 期刊: Quarterly Journal of the Royal Meteorological Society
• 影响因子: 8.9
• 作者: Burton R