中文摘要：

中国北方沙漠和沙地是亚洲粉尘释放的重要源区,定量估算这一地区的粉尘释放量有助于评估区域大气环境质量及其气候效应.目前,对中国北方粉尘释放量的估算主要是基于模拟结果,野外直接观测数据很少.利用一种新型的粉尘释放观测仪器——便携式粉尘观测仪（PI-SWERL）,测量腾格里沙漠和毛乌素沙地若干典型地表（沙丘、干湖、灌丛沙丘、河流冲积物等）的粉尘释放通量,获得了不同地表潜在粉尘释放量的直接观测数据.结果表明,不同地表的PM10释放通量存在较大差异,但均随摩阻风速的增加而增加.在相同的摩阻风速U＊=0.55 m/s条件下,灌丛沙丘的PM10通量最高（0.70~10.23 mg/（m2 s））,河流冲积物次之（0.12~4.97 mg/（m2 s））,干湖湖底、沙丘等地表的通量较小（〈0.5 mg/（m2 s））.对比试验表明,破碎结壳地表释放的PM10通量是未破碎结壳的几倍甚至几十倍;披覆松散沙粒结壳地面的PM10释放通量高出未披覆的1~2个数量级.对比前人研究结果,PI-SWERL可以较好地反映不同源区粉尘释放的差异,对定量评估区域乃至全球的粉尘释放量等具有重要意义.

英文摘要：

The deserts and sand fields of northern China are important sources of dust in Asia. Quantitative estimations of dust emission flux in this region will contribute to the assessment of regional environmental air quality and its climatic impact. Previous evaluations of dust emission have largely been based on numerical simulations with few direct field measurements. In this study, we used the new portable in situ wind erosion laboratory（PI-SWERL） to measure the dust emission fluxes of several typical surface sediments（i.e., dunes, dry lakes, coppice dunes, and fluvial deposits） in the Tengger Desert and Mu Us sand field, from which the potential emission fluxes of the different soil/sediment types were derived. Our results showed that dust emissions could be characterized into four basic types, indicating the comprehensive effect of aerodynamic entrainment and sand saltation on dust emission. Furthermore, irrespective of whether the particles are clay or silt, supply should be considered when evaluating dust emission. It was found that PM10 emission flux varies with landform surface and increases with friction velocity（U＊）. When U＊ = 0.55 m/s, the PM10 emission flux of coppice dunes is greatest（0.70–10.23 mg/（m2 s））, followed by fluvial deposits（0.12–4.97 mg/（m2 s））; the fluxes of dry lakes and sand dunes are both low（〈0.5 mg/（m2 s））. To understand the influence of surface crust on dust emission, we designed an experiment to investigate its effects. It was revealed that the PM10 emission flux of a crusted surface is several times or even dozens of times greater than without a crust; sand particles on a crusted surface also increase the PM10 emission flux by 1–2 orders of magnitude. The reliability and accuracy of our data were verified against the results of previous studies; some differences could be attributed to the effects of climate, soil, and topography. We demonstrate that PI-SWERL can be used to reflect differences in the emissions of different dust sources, w