In drylands around the world, ephemeral lakes (playas) are common. Dry, wind-erodible playa sediments are potent local and regional sources of dust and PM10 (airborne particles with diameters less than 10 μm). Dust clouds often cause sudden and/or prolonged loss of visibility to travelers on downwind roadways. Lordsburg Playa, in southwestern New Mexico, USA is bisected by Interstate Highway 10. Dust storms emanating from the playa have been responsible for numerous visibility-related road closures (including 39 road closures between 2012 and 2019) causing major economic losses, in addition to well over a hundred dust-related vehicle crashes causing at least 41 lost lives in the last 53 years. In order to improve understanding of the surfaces responsible for the dust emissions, we investigated the critical wind friction velocity thresholds and the dust emissivities of surfaces representing areas typical of Lordsburg Playa’s stream deltas, shorelines, and ephemerally flooded lakebed using a Portable In-Situ Wind ERosion Laboratory (PI-SWERL). Mean threshold friction velocities for PM10 entrainment ranged from less than 0.30 m s− 1 for areas in the delta and shoreline to greater than 0.55 m s− 1 for ephemerally flooded areas of the lakebed. Similarly, we quantified mean PM10 vertical flux rates ranging from less than 500 μg m− 2 s− 1 for ephemerally flooded areas of lakebed to nearly 25,000 μg m− 2 s− 1 for disturbed delta surfaces. The unlimited PM10 supply of the relatively coarse sediments along the western shoreline is problematic and indicates that this may be the source area for longer-term visibility reducing dust events and should be a focus area for dust mitigation efforts.

中文翻译：

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美国新墨西哥州西南部洛德斯堡海滩的能见度危害评估中的粉尘排放源表征

在世界各地的干旱地区，短暂的湖泊（Playas）很常见。干燥的，易风蚀的普拉亚沉积物是粉尘和PM10（直径小于10μm的空气传播颗粒）的重要局部和区域来源。尘云经常导致顺风道路上的旅行者突然和/或长时间失去能见度。美国新墨西哥州西南部的洛德斯堡海滩（Lordsburg Playa）被10号州际公路一分为二。从海滩散发出的沙尘暴造成了许多与能见度相关的道路封闭（包括2012年至2019年之间的39条道路封闭），除了造成了重大经济损失外，在过去的53年中，发生了一百多起与灰尘有关的车祸，至少造成41人丧生。为了更好地了解造成粉尘排放的表面，我们使用便携式现场风蚀实验室（PI-SWERL）研究了代表劳德斯堡普拉亚河三角洲，海岸线和短暂被湖水淹没的典型区域的临界风摩擦速度阈值和表面的尘埃发射率。PM10夹带的平均阈值摩擦速度在三角洲和海岸线区域小于0.30 m s-1到湖床短暂泛滥的区域大于0.55 m s-1。同样，我们量化了PM10的平均垂直通量率，范围从湖床短暂淹没区域的小于500μgm-2 s-1到受干扰三角洲表面的近25,000μgm-2 s-1。