Aerosols-Climate Interactions: The Relationship between Desert Dust and Atmospheric Convection

这项研究项目将研究干旱土地表面的矿物粉尘是如何被强对流羽流注入大气中的，特别是那些被称为“尘暴”的旋转羽流。研究人员怀疑，沙尘暴是大气尘埃的重要来源，因此会影响区域和全球范围的气候。这项提议的目标是测量尘埃表面通量及其垂直运移，并利用这些测量结果建立干旱地区尘埃来源的参数表示法。这项工作的基础是两个假设：(1)相干对流羽流和沙尘暴在尘埃的垂直输送中发挥重要作用；(2)当地表受到耕作和其他农业做法的干扰时，这种输送的强度会增加，这也会导致对流运动的强度增加。测量将在亚利桑那州的一个现场使用激光雷达、小型仪表式飞机和地面仪器进行。这项研究还将包括测试一种可以测量气溶胶表面通量的新仪器。一个基于网络的教育部分将描述沙尘暴和相关现象，并将对比它们在地球和火星上的发生方式。这项研究的预期结果将是测试和改进拟议的通过尘暴和其他相干对流羽流进入大气层的尘埃数量和分布的新表示法。然后，这一参数表示将可用于气候模型和其他运输模型，这反过来又可以改进对全球沙尘分布及其对气候系统影响的估计。

This research project will examine how mineral dust from the surface of arid land is injected into the atmosphere by strong convective plumes, especially those whirling ones called "dust devils." The investigators suspect that dust devils are a significant source of atmospheric dust and therefore affect climate on regional and global scales. The objectives of this proposal are to measure the surface flux of dust and its vertical transport and to use those measurements to develop parameterized representations of this source of dust from arid regions. Two hypotheses form the basis for this work: (i) coherent convective plumes and dust devils play a significant role in the vertical transport of dust; and (ii) the magnitude of that transport is increased when the surface is disturbed by plowing and other agricultural practices, which also cause an increase in the intensity of the convective motions. Measurements will be made at a field site in Arizona using a lidar, a small instrumented aircraft, and surface instruments. The research will also include testing of a new instrument that can measure the surface flux of aerosols. A web-based educational component will describe dust devils and related phenomena and will contrast how they occur on Earth and on Mars. The expected outcome of the research will be to test and refine a proposed new representation of the amount and distribution of dust that enters the atmosphere through dust devils and other coherent convective plumes. This parameterized representation will then be available for inclusion in climate models and other transport models, which in turn can provide improved estimates of the global distribution of dust and its effect on the climate system.