Consequences of DESERTification for the radiaTive Impact of atmospheric dust over the Middle East (DESERT-TIME)

沙漠化对中东地区大气尘埃辐射影响的后果（沙漠时间）

• 批准号: 414044717
• 负责人: Dr. Jamie Banks
• 金额: --
• 依托单位: Abteilung Modellierung atmosphärischer Prozesse
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/414044717?language=en
• 关键词: Consequences; DESERTification; radiaTive; Impact; atmospheric

Droughts in the Middle East over recent decades have had serious consequences for water and food security, threatening the health and livelihoods of millions of people in the region. As croplands and other vegetated areas become drier, desertification causes crop failure and leaves land exposed to the spread of neighbouring deserts. Dry, exposed soil is vulnerable to being blown off the surface by strong winds, and so dust storms are a common feature of desert environments. If deserts spread, then it is to be expected that so too would dust storms become more frequent and more intense, which can degrade the quality of the air and be harmful to human health.Atmospheric dust also affects the Earth’s thermostat, by influencing the warming or cooling of the environment. When a dust storm passes over a region, it will reflect light from the Sun, and so it will tend to cool the Earth’s surface. On the other hand, the dust will also absorb some of this incoming light from the Sun, and so dust may warm the Earth’s atmosphere. However, this warming will occur mostly in the vicinity of the dust layer, so the altitude of the dust influences the warming or cooling of the Earth’s atmosphere.Various questions therefore emerge as to the impact of desertification on the Middle Eastern environment:1) To what extent have recent droughts increased the spread of dust storms in the region? Dust storms have been observed to have increased in frequency, but what has been the increase in their quantity? Dust transport models can provide precise answers to these questions by simulating the differences in dust activity between various scenarios: in this case, simulations will be performed using ‘non-drought’ and drier ‘drought’ scenarios, representing the differences in the vegetation and soil between the two cases. The hypothesis is that the latter scenario will produce more frequent and more intense dust events, and the simulations will calculate the extent to which this is the case.2) How has this change in dust activity affected the influence of dust on the warming or cooling of the Earth’s surface and atmosphere? These effects will be calculated under both conditions of non-drought and drought, so that the differences can be analysed. Measurements made at the surface and from satellites will also be used, in order to enhance our understanding of the environmental influences on these effects.3) To what extent is this change in dust activity measurable from regional satellite data? Satellite measurements will be compared with the simulations in order to show which drought scenario more accurately represents the observed behaviour of dust in the atmosphere. This will also provide further insights as to the ability to infer from the satellite measurements the warming or cooling of the atmosphere due to dust.Asking and answering these questions will provide further insights into the effects of Middle Eastern desertification and dust on the atmospheric environment.

近几十年来，中东的干旱对水和粮食安全造成了严重后果，威胁到该地区数百万人的健康和生计。随着农田和其他植被地区变得更加干燥，荒漠化导致作物歉收，使土地暴露在邻近沙漠蔓延的威胁之下。干燥、裸露的土壤很容易被强风从表面吹走，因此沙尘暴是沙漠环境的常见特征。如果沙漠蔓延，那么可以预料，沙尘暴也会变得更加频繁和强烈，这会降低空气质量，对人类健康有害。大气灰尘也会影响地球的恒温器，影响环境的升温或降温。当沙尘暴经过一个地区时，它会反射来自太阳的光线，因此它会使地球表面变冷。另一方面，尘埃也会吸收一些来自太阳的光线，因此尘埃可能会使地球的大气层变暖。然而，这种变暖主要发生在沙尘层附近，因此沙尘的高度影响着地球大气的变暖或变冷。因此，关于沙漠化对中东环境的影响，出现了各种各样的问题：1）最近的干旱在多大程度上增加了该地区沙尘暴的传播？据观察，沙尘暴的频率有所增加，但其数量的增加是什么？沙尘传输模型可以通过模拟各种情景之间沙尘活动的差异来精确回答这些问题：在这种情况下，将使用“非干旱”和较干燥的“干旱”情景进行模拟，代表两种情景之间植被和土壤的差异。假设后一种情况将产生更频繁和更强烈的尘埃事件，模拟将计算这种情况的程度。2）尘埃活动的这种变化如何影响尘埃对地球表面和大气的变暖或变冷的影响？将在非干旱和干旱两种情况下计算这些影响，以便分析差异。还将使用在地面和从卫星上进行的测量，以加强我们对环境对这些效应的影响的理解。3）在多大程度上可以从区域卫星数据中测量尘埃活动的这种变化？将把卫星测量结果与模拟结果进行比较，以表明哪种干旱情景更准确地反映了观测到的大气中尘埃的行为。这也将使人们更深入地了解从卫星测量数据推断沙尘造成的大气变暖或变冷的能力，提出和回答这些问题将使人们更深入地了解中东荒漠化和沙尘对大气环境的影响。