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

这个研究项目将研究来自干旱地区表面的矿物粉尘是如何通过强对流羽流，特别是那些被称为“尘卷风”的旋转羽流注入大气的。研究人员怀疑，尘卷风是大气尘埃的重要来源，因此在区域和全球范围内影响气候。这项建议的目标是测量沙尘的表面通量及其垂直输送，并利用这些测量结果对干旱地区的沙尘来源进行参数化表示。两个假设构成了这项工作的基础：(i)相干对流羽流和尘卷在尘埃的垂直输送中起重要作用；（ii）当地表受到耕作和其他农业活动的干扰时，这种输送的强度会增加，这也会导致对流运动强度的增加。测量将在亚利桑那州的一个现场进行，使用激光雷达、小型仪器飞机和地面仪器。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尘卷风和相关现象，并将它们在地球和火星上的发生方式进行对比。这项研究的预期结果将是测试和完善一种新的关于通过尘卷风和其他连贯对流羽流进入大气的尘埃数量和分布的表述。然后，这种参数化表示将可用于气候模式和其他运输模式，这反过来又可以提供对全球沙尘分布及其对气候系统影响的改进估计。

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.