Department of Geosciences, The University of Tulsa, Tulsa, OK 74104, USA.
Department of Geosciences, Texas Tech University, Lubbock, TX 79409, USA.
Sci Total Environ. 2018 Apr 15;621:1023-1032. doi: 10.1016/j.scitotenv.2017.10.124. Epub 2017 Nov 6.
Despite the widespread media attention of chain-reaction traffic incidents and property damage caused by windblown dust in the U.S. and elsewhere in the world, very few studies have provided in-depth analysis on this issue. Remote sensing and field observations reveal that wind erosion in the southwestern U.S. typically occurs in localized source areas, characterized as "hotspots", while most of the landscape is not eroding. In this study, we identified the spatial and temporal distribution patterns of hotspots that may contribute dust blowing onto highways in the southwestern U.S. We further classified the hotspots for the potential of blowing dust production based upon field observations and wind erosion modeling. Results of land use and land cover show that shrubland, grassland, and cropland accounted for 42%, 31%, and 21% of the overall study area, respectively. However, of the 620 total hotspots identified, 164 (26%), 141 (22%), and 234 (38%) are located on shrubland, grassland, and cropland, respectively. Barren land represented 0.9% of the land area but 8% of the dust hotspots. While a majority of these hotspots are located close to highways, we focused on 55 of them, which are located <1km to adjacent highways and accessible via non-private roads. Field investigations and laboratory analysis showed that soils at these hotspot sites are dominated by sand and silt particles with threshold shear velocities ranging from 0.17-0.78m s, largely depending on the land use of the hotspot sites. Dust emission modeling showed that 13 hotspot sites could produce annual emissions >3.79kg m, yielding highly hazardous dust emissions to ground transportation with visibility <200m. Results of location, timing, and magnitude of the dust production at the hotspots are critical information for highway authorities to make informed and timely management decisions when wind events strike.
尽管美国和世界其他地区的媒体广泛关注连锁反应交通事故和扬尘造成的财产损失，但很少有研究对此问题进行深入分析。遥感和实地观测表明，美国西南部的风蚀通常发生在局部源区，这些源区被称为“热点”，而大部分景观并没有发生侵蚀。在本研究中，我们确定了可能导致美国西南部高速公路扬尘的热点的时空分布模式。我们进一步根据实地观测和风力侵蚀模型对潜在扬尘产生的热点进行了分类。土地利用和土地覆盖的结果表明，灌木林、草地和耕地分别占研究区总面积的 42%、31%和 21%。然而，在所确定的 620 个总热点中，有 164 个（26%）、141 个（22%）和 234 个（38%）分别位于灌木林、草地和耕地，荒地占土地面积的 0.9%，但占尘源热点的 8%。虽然这些热点中的大多数都位于高速公路附近，但我们关注的是其中的 55 个热点，这些热点距离相邻的高速公路<1km，可通过非私人道路到达。实地调查和实验室分析表明，这些热点土壤以砂和粉砂颗粒为主，其起动剪切速度范围从 0.17-0.78m/s，这主要取决于热点的土地利用情况。粉尘排放模型表明，13 个热点每年的排放量>3.79kg m，对能见度<200m 的地面交通产生极高危害的粉尘排放。热点处粉尘产生的位置、时间和规模的结果为公路管理部门在风力事件发生时提供了关键信息，以便做出明智和及时的管理决策。
