Lagrangian dust model simulations for a case of moist convective dust emission and transport in the western Sahara region during Fennec/LADUNEX
Lagrangian dust model simulations for a case of moist convective dust emission and transport in the western Sahara region during Fennec/LADUNEX
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DOI：
10.1002/2015jd023283
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发表时间：
2015-06
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影响因子：
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通讯作者：
H. Sodemann;T. Lai;F. Marenco;C. Ryder;C. Flamant;P. Knippertz;P. Rosenberg;M. Bart;J. McQuaid
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文献类型：
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作者：
H. Sodemann;T. Lai;F. Marenco;C. Ryder;C. Flamant;P. Knippertz;P. Rosenberg;M. Bart;J. McQuaid
由于沙漠地区的严酷和难以进入，在表面，空中运输和沉积的灰尘动员过程的不确定性仍然是相当大的，限制了进行模型模拟的能力。2011年6月，在西撒哈拉地区的芬尼克/拉格朗日尘源反演实验实地活动中获得了一套全面的地面和空中原位测量和遥感观测数据。在这里，我们评估了最先进的拉格朗日粒子扩散模型FLEXPART的能力，新配备了灰尘动员能力，以模拟该地区的灰尘输送。我们调查的情况下，一个大的中尺度对流系统（MCS）引发的灰尘排放在马里中部，随后移动到毛里塔尼亚北部北方作为一个大的冷池灰尘前。在这种情况下，沙尘动员被证明是模拟沙尘输送的一个重要障碍，因为MCS和相关的冷池引起的沙尘排放都没有在气象分析中表现出来。因此，获得一个现实的尘埃运输模拟这种情况下，需要一个反演方法，使用人工规格的尘埃源支持卫星图像。与两架飞机的现场和遥感数据相比，拉格朗日尘埃输送模拟很好地代表了尘埃羽流的整体形状和演变。虽然在模拟中很好地代表了积累和粗模式尘埃，巨模式粒子被大大低估。我们的研究结果再次强调，与深层湿对流相关的沙尘排放仍然是北方非洲可靠的沙尘模式模拟的关键问题。
Due to the harshness and inaccessibility of desert regions, the uncertainties concerning the processes of dust mobilization at the surface, airborne transport, and sedimentation are still considerable, limiting the ability to perform model simulations. In June 2011, a comprehensive data set of ground‐based and airborne in situ measurements and remote sensing observations was acquired within the Fennec/Lagrangian Dust Source Inversion Experiment (LADUNEX) field campaign in the western Sahara region. Here we evaluate the ability of the state‐of‐the‐art Lagrangian particle dispersion model FLEXPART, newly fitted with a dust mobilization capability, to simulate dust transport in this region. We investigate a case where a large mesoscale convective system (MCS) triggered dust emissions in central Mali, which subsequently moved as a large cold pool dust front toward northern Mauritania. Specifying dust mobilization for this case is shown to be an important obstacle to simulating dust transport during this event, since neither the MCS nor the associated cold pool‐causing dust emission is represented in the meteorological analysis. Obtaining a realistic dust transport simulation for this case therefore requires an inversion approach using a manual specification of the dust sources supported by satellite imagery. When compared to in situ and remote sensing data from two aircraft, the Lagrangian dust transport simulations represent the overall shape and evolution of the dust plume well. While accumulation and coarse mode dust are well represented in the simulation, giant mode particles are considerably underestimated. Our results re‐emphasize that dust emission associated with deep moist convection remains a key issue for reliable dust model simulations in northern Africa.